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Component Engineering Training Course. This Training Course has been compiled and is presented by Spur Electron Ltd. WHAT IS COMPONENT ENGINEERING?. It is an individual or group which provides the project team with a broad knowledge and experience of EEE components, including:

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Component engineering training course

Component Engineering Training Course

This Training Course has been compiled and is presented by Spur Electron Ltd.


What is component engineering
WHAT IS COMPONENT ENGINEERING?

  • It is an individual or group which provides the project team with a broad knowledge and experience of EEE components, including:

  • Electronic and semiconductor theory and principals

  • Materials, construction and manufacture

  • Space component procurement systems

  • Quality and screening requirements


High reliability components
HIGH RELIABILITY COMPONENTS

  • DEFINITION : A component is defined as :-

  • The smallest sub-division of a system which cannot be further sub- divided without destroying its function.

  • EEE stands for :-

  • E Electrical, e.g. Resistors, Capacitors, Connectors

  • E Electromechanical, e.g. Relays, Switches, Actuators

  • E Electronic, e.g. Integrated Circuits, Transistors, Diodes


High reliability components cont
HIGH RELIABILITY COMPONENTS (CONT.)

  • Europeans tend to use the word “Component”, whereas the Americans use the term “Part”. Both terms will be found within this presentation, and should be considered as synonymous.

  • Europeans use the term “High Reliability Components, Americans often use the term “Hi-Rel Part”. Again the terms are synonymous.

  • High Reliability components are those in which a very high degree of confidence can be placed that they have stable characteristics and a working life in excess of the mission requirements.

  • This definition is flawed, in that the components are manufactured to a standard set of requirements, whilst mission duration's vary considerably.


High reliability components cont1
HIGH RELIABILITY COMPONENTS (CONT.)

  • A decade ago mission duration's were typically 3 to 5 years. Today mission duration's of up to 15 to 20 years are required.

  • The US Military market has led the field in specifying reliability standards.

  • In the mid 1960’s, various government agencies identified that defects, able to be screened out, were resulting in an equipment failure rate of about 1% per thousand hours.

  • In-depth failure analysis identified the predominant failure mechanisms.


High reliability components cont2
HIGH RELIABILITY COMPONENTS (CONT.)

  • The Solid State Applications Branch of the RADC was assigned the task of developing a screening procedure to remove the infant mortality failures, which led to the high failure rates previously encountered.

  • In 1968 the RADC staff developed MIL-STD-883.



Operating environment for space components
OPERATING ENVIRONMENT FOR SPACE COMPONENTS

  • Environmental Extremes:

  • Temperature

  • Radiation

  • Mechanical Stresses

  • Vacuum



Origins of the esa scc system
ORIGINS OF THE ESA/SCC SYSTEM

  • Need for Pan-European Specification System for EEE Components realized by ESRO, prior to the formation of ESA.

  • Until this need was recognized and acted upon a range of differing specification systems were being used


Origins of the esa scc system cont
ORIGINS OF THE ESA/SCC SYSTEM (CONT.)

  • This resulted in:

  • - No standardization.

  • - Wide variations in test and inspection philosophies.

  • - Huge variances in manufacturers quoted price and delivery.

  • - Extreme difficulty in assessing comparative quality and reliability of delivered components.


Origins of the esa scc system cont1
ORIGINS OF THE ESA/SCC SYSTEM (CONT.)

  • In 1971 ESRO through its Joint Programmes and Policy Committee (JPPC) set up the Space Components Coordination Group (SCCG) on an interim basis as an advisory group.

  • Over 30 years later, this interim group is still operating.

  • In 1973 the JPPC approved the SCCG Terms of Reference.

  • The SCCG now set about the generation of a series of basic policy documents.


Origins of the esa scc system cont2
ORIGINS OF THE ESA/SCC SYSTEM (CONT.)

  • These documents were approved by the SCCG at its plenary meeting in November 1973 and submitted to the JPPC for its approval.

  • Before approval by the JPPC, ESRO and ELDO were merged into the present day ESA.

  • ESA then abolished the JPPC, and the SCCG was placed under the direct authority of the Director General.


Origins of the esa scc system cont3
ORIGINS OF THE ESA/SCC SYSTEM (CONT.)

  • This new status entailed new terms of reference and redefinition of responsibilities for both the SCCG and the Director General.

  • The placement of the SCCG under the Director General's control was finally approved in 1976.

  • This ESA policy has been superseded by ESCC and SCAHC


Objectives of the esa scc system
OBJECTIVES OF THE ESA/SCC SYSTEM

  • The basic objectives of the ESA/SCC System as defined by ESA/SCC Document No. 00000 “Object and Basic Rules of the ESA/SCC System” are:

  • - Political. The promotion of a European System of

  • Specifications for Space Components.

  • - Technical. The System capable of being integrated

  • with other international systems.

  • - Commercial. Promotion of the production in Europe of Components suitable for Space Application.


Objectives of the esa scc system1
OBJECTIVES OF THE ESA/SCC SYSTEM

  • Standardisation

  • Interchangability

  • Improvement cost/schedule planning


Sccg achievements
SCCG ACHIEVEMENTS

  • By the early 1980s the SCCG had achieved a very complete ESA/SCC System comprising over 1000 specifications and had assisted in the qualification of some 350 components manufactured by a total of 40 European manufacturers.

  • In spite of this success the European user community were very concerned that ESA/SCC components were significantly more expensive than space qualified components from the US.

  • There was also a major concern that the SCCG was overly bureaucratic and the ESA/SCC System over specified technical requirements.

  • In 1993 ESA published a technical paper recommending some major areas of review and modification.

  • This lead to the formation of SCAHC.


Scahc
SCAHC

  • What was SCAHC?

  • The Space Components Ad Hoc Committee (SCAHC) was established by ESA in October 1994

  • It comprised of experts from all the main space sectors within Europe. i.e. ESA, National Space Agencies, Commercial Space Organisations, Space Industry and Space Component Manufacturers. In addition the European Commission was also represented.

  • The SCAHC task was to formulate a long term programme for space components that would enhance European competitiveness in the world market.


Scahc recommendations
SCAHC RECOMMENDATIONS

  • In a final report released in 1995 the SCAHC made ten recommendations:

  • R1 – Maintain the ESA/SCC System of specifications including related qualification programmes and quality assurance approach in order to meet users needs and market trends.

  • R2 – Standards and specifications for components shall reflect a higher degree of delegation from suppliers with reduced customers controls.

  • R3 – Wherever possible, European component specifications and standards should be based on international standards and should be promoted to obtain international recognition.


Scahc recommendations cont
SCAHC RECOMMENDATIONS (CONT.)

  • R4 – Implement a stringent system for the reduction of diversity of components for use in space, based on the usage of a European Preferred Parts List, giving preference to European components.

  • R5 – Establish a reliability system for European space Components

  • R6 – Establish an information Exchange system on component data with access for all European users.

  • R7 – Enable the mutual recognition of industrial performance in the various component disciplines, including component engineering, radiation hardness assurance, auditing and inspection (with formal certification of the latter), through provision of the relevant and regular training opportunities.


Scahc recommendations cont1
SCAHC RECOMMENDATIONS (CONT.)

  • R8 – Improve the availability of strategically important components, giving preference to European sources (Microprocessors, MMICs etc).

  • R9 – Implement, in full partnership with the users, manufacturers, commercial customers and agencies, a European Space Component Research and Technology Programme assuring coherence with other market sectors, and cost effectiveness.

  • R10 – Establish a permanent Component Steering Board (CSB) representing the interests of all the European space partners, to monitor market trends, to provide financing and to overview the technology programmes and its synergies, and advise on necessary policy changes.


Scsb acheivements to date
SCSB ACHEIVEMENTS TO DATE

  • In the 7 years since the SCAHC recommendations were made progress has been slow but reasonably successful.

  • Using the recommendations as a guide we can demonstrate the following achievements.

  • R1 Maintain but improve the ESA/SCC system.

  • Two major contracts awarded. One to review the structure and organisation, relatively successful, the SCSB now responsible for the policy and the Executive responsible for the day to day operation.

  • Second contract to carry out in depth review. Results very controversial. However general agreement appears to have been reached, some changes already incorporated, some still to be made.


Acheivements to date cont
ACHEIVEMENTS TO DATE (CONT.)

  • R2 Reduce Customer Controls.

  • Partially achieved by the reduction of deliverable documentation, now incorporated into the system.

  • R3 Gain international recognition for the system

  • NASA now accept ESA/SCC Level B as equivalent to US MIL Level S

  • R4 Establish a European PPL

  • Now available on ESCIES (see later)

  • R5 Establish a European reliability system

  • Problem found to be an international concern. NASA and NASDA are currently involved in seeking solutions.

  • R6 Establish Information Exchange Database

  • Now Established (see ESCIES).


Acheivements to date cont1
ACHEIVEMENTS TO DATE (CONT.)

  • R7 Enable mutual recognition.

  • Set of training programmes envisioned. Still not fully initiated.

  • R8 Improve availability of strategically important components.

  • Incorporate into CTB activities, see R9 below.

  • R9 Establish a Component Technology Board.

  • The CTB is well established and has developed it’s own five year plan. However funding availability is a major concern.

  • R10 Establish a Space Components Steering Board (SCSB).

  • SCSB Charter was formally signed on 8th October 2002


Mr rodot signs the charter
MR. RODOTẦ SIGNS THE CHARTER


Esa scc still the standard
ESA/SCC STILL THE STANDARD

  • Even though the ESCC is intended to replace the ESA/SCC System, it hasn’t yet happened and is unlikely to be complete for a number of years. In the meantime the ESA/SCC System continues to be the preferred standard.


Relationship to the ecss system
RELATIONSHIP TO THE ECSS SYSTEM

  • The ESA/SCC specification system is a self contained subset of the ECSS System in that ECSS-Q-00 identifies that components shall be procured by means of the ESA/SCC specification system, thus making it a part of the ECSS system.

  • ECSS-Q-60 is the Level II document applicable for EEE components. This document clearly identifies the requirement for maximum use and preference towards the ESA/SCC Specification System.


Esa scc document ref 001
ESA/SCC DOCUMENT REF/001

  • This identifies the existence and status of all documents and specifications issued on behalf of the Director General of ESA.

  • It is regularly updated and issued to all registered users of the ESA/SCC System.

  • At this time, this document comprises a total of >1000 documents and specifications, including:-

  • Percentage of Total Documents

  • Level 0 Series - Object and Basic Rules 0.5%

  • Level 1 Series - Organization, Procedures and Implementation 1.0%

  • Level 2 Series - Basic Specifications 10.5%

  • Level 3 Series - Generic Specifications 3.0%

  • Level 4 Series - Detail Specifications 86%



Level 2 documents basic specifications
LEVEL 2 DOCUMENTS BASIC SPECIFICATIONS

  • These specifications define the basic requirements for a process, document or test method.

  • There is no standard table of contents owing to the wide range of topics addressed.

  • Employs either a 5 or 7 digit code,

  • i.e. either

  • 20400 Internal Visual Inspection

  • 2049000 Internal Visual Inspection of Integrated Circuits


Basic specifications examples
BASIC SPECIFICATIONS (EXAMPLES)

  • TEST METHODS

  • 22900 Total Dose Steady-State Irradiation Test Method

  • 23800 Electrostatic Discharge Sensitivity Test Method

  • 24800 Resistance to Solvents of Marking Materials and Finishes


Basic specifications examples cont
BASIC SPECIFICATIONS (EXAMPLES) (CONT.)

  • INSPECTION METHODS

  • 2049000 Internal Visual Inspection of Integrated Circuits

  • 20500 External Visual Inspection

  • 21400 Scanning Electron Microscope Inspection


Basic specifications examples cont1
BASIC SPECIFICATIONS (EXAMPLES) (CONT.)

  • SYSTEM REQUIREMENTS

  • 20100 Requirements for Qualification of Standard Electronic Components for Space Application

  • 21500 Calibration System Requirements

  • 2263502 Evaluation Test Programme for Surface Acoustic Wave (SAW) Devices

  • 22800 ESA/SCC Non-Conformance System

  • 24600 Minimum Quality System Requirements


Level 3 documents generic specifications
LEVEL 3 DOCUMENTS GENERIC SPECIFICATIONS

  • GENERIC SPECIFICATIONS:

  • - Generic meaning “CLOSELY RELATING TO ANY GROUP OR CLASS”.

  • - It defines the general Inspection, Test and Documentation requirements for a group of components.

  • - Employs a Four Digit Code, and may refer to a Family of components or a Sub-Family of components.

  • An example to illustrate its use:-

  • EXAMPLE

  • 4001

  • 40 = Family Code (Resistor Family)

  • 01 = Sub-Family Code (Metal Film)


Generic specification contents
GENERIC SPECIFICATION CONTENTS

  • Defines the general requirements for a component family, including:

  • Qualification Approval

  • Capability Approval

  • Procurement

  • Lot Acceptance Testing

  • Delivery

  • Inspection & Test Schedules

  • Data Documentation


Generic specification
GENERIC SPECIFICATION

  • TABLE OF CONTENTS

  • 1. Introduction

  • 2. Applicable Documents

  • 3. Terms, Definitions, Abbreviations, Symbols and Units

  • 4. Requirements

  • 5. Production Control for Qualification and Capability Approval

  • 6. Final Production Tests

  • 7. Burn-in and Electrical Measurements

  • 8. Qualification Approval, Capability Approval and Lot Acceptance

  • Tests

  • 9. Test Methods and Procedures

  • 10. Data Documentation

  • 11. Delivery

  • 12. Packaging and Despatch

  • -- Test Flows --

  • -- Sampling Plans --


Generic specifications examples cont
GENERIC SPECIFICATIONS (EXAMPLES) (CONT.)

  • 3009 Capacitors, fixed, chips, ceramic dielectric types I and II

  • 4001 Resistors, fixed film

  • 5000 Discrete Semiconductor Components

  • 9000 Integrated Circuits, Monolithics.


Level 4 documents detail specifications
LEVEL 4 DOCUMENTS DETAIL SPECIFICATIONS

  • Defines the detail requirements for a component type, including:-

  • Ratings

  • Physical and Electrical Characteristics

  • Test and Inspection Data

  • TABLE OF CONTENTS

  • 1. General

  • 2. Applicable Documents

  • 3. Terms, Definitions, Abbreviations, Symbols and Units

  • 4. Requirements

  • 5. Tables

  • 6. Figures

  • 7. Appendices


Detailed specification examples
DETAILED SPECIFICATION EXAMPLES

  • 3009/004 Capacitors, fixed, chips, ceramic dielectric type I.

  • 4001/011 Resistors, fixed film, Non hermetically sealed.

  • 5000/005 Diodes, silicon, fast recovery, avalanche rectifiers, 400W.

  • 9000/001 Monolithic microwave integrated circuits (MMIC), GaAs, Travelling wave amplifier.




Other procurement systems
OTHER PROCUREMENT SYSTEMS

  • CECC

  • NASA

  • US MILITARY


CECC

  • The Cenelec Electronic Components Committee (CECC) System for electronic components of assessed quality became operational in 1973.

  • Its object is to facilitate trade by the harmonization of specifications and quality assessment procedures for electronic components.

  • Components produced under CECC requirements carry a special mark and are accepted by all member states.

  • 15 countries participate in the CECC System:-

  • Austria, Denmark, France, Belgium, Finland, Germany, Ireland, Italy, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom.



Cecc cont
CECC (Cont.)

  • There are a number of different types of approval available within CECC.

  • Manufacturers, specialist contractors, distributors and independent test houses, can each be approved for their particular capability.

  • Each approval carries its own award of a certificate.


CECC

  • Qualification Approval, CECC 00 114:part II

  • Enhanced Assessment of Quality, CECC 00 114:part IV

  • Capability Approval, CECC 00 114:part III

  • Technology Approval, CECC 00 114:part VI

  • Process Approval, CECC 00 114:part V

  • Distributor Approval, CECC 00 114:part 1

  • Test Laboratory Approval, CECC 00 114:part 1


NASA

  • The National Aeronautics and Space Administration, NASA, was formerly established in 1958, to plan and execute the US civil space programme. It comprises about a dozen major facilities, employing around 25,000 civil servants.


Main nasa sites
MAIN NASA SITES

  • Goddard Space Flight Centre (GSFC)

  • Jet Propulsion Laboratory (JPL)

  • Kennedy Space Centre (KSC)

  • Marshall Space Flight Centre (MSFC)


Nhb 5300 4
NHB 5300.4

  • NASA programmes are controlled through a top level handbook, NHB 5300.4

  • This document is imposed on all contractors.

  • It details the requirements for the control, selection, procurement, testing and application of all flight and mission essential EEE components.

  • The hand book is divided into two major sections, Programme Management and Component Requirements.


Nhb 5300 4 cont
NHB 5300.4 (Cont.)

  • The Programme Management Section also identifies the requirements to provide data to NASA in electronic form.

  • The Component Requirements Section addresses the detailed topics directly related to components including, selection and specification, screening, parts lists, critical parts, derating, GIDEP, traceability, handling, packaging and storage, qualification and quality conformance tests, receiving inspection and manufacturer surveillance.


Gsfc preferred parts list
GSFC PREFERRED PARTS LIST

  • There are numerous PPLs used within the US space industry, however the GSFC PPL is considered as one of the best.

  • It contains a list of preferred parts in two quality levels: Grade 1 for higher quality/critical applications and Grade 2 for less demanding applications.


Us military standards
US MILITARY STANDARDS

  • In the 1950s the US government, in conjunction with the American armed forces, introduced a series of documents to standardize the screening flows for electrical and electromechanical components. The system has continued to evolve, and now includes electronic components. The objectives being:

  • Total product Interchangeability

  • Configuration control

  • Efficiency of volume production

  • Maximum number of approved sources

  • These aims have in the most part been achieved


Mil std 883
MIL-STD-883

  • In the early 1960s the rapidly growing Integrated Circuit industry was coming of age. It was recognised that the level of defects attributable to Infant Mortality could be significantly reduced if a standardized screening flow were introduced. The Solid State Applications Branch of the Air Forces, Rome Air Defence Center (RADC) was given the task.


Mil std 883 objective
MIL-STD-883 OBJECTIVE

  • To create an economically feasible, standardized IC screening flow, to achieve equipment failure rates of :-

  • 0.085% per 1000hrs., class B (Military)

  • 0.004% per 1000hrs., class S (Space)


883 original screening flows
883 ORIGINAL SCREENING FLOWS

  • Originally there were three screening flow classes, A,B and C:-

  • Class A, critical non-repairable applications

  • Class B, high reliability, maintainable

  • Class C, non-critical ground applications

  • Class A, was superseded by Class S in 1977

  • Class C, was dropped in 1984, lack of use.


883 detailed specifications
883 DETAILED SPECIFICATIONS

  • MIL-STD-883 is a collection of test methods designed to look at specific reliability and quality concerns affecting semiconductor products.

  • The specification covers Environmental, Mechanical and Electrical test methods.

  • In addition 883 also covers a range of procedures.




38510 qualification and quality conformance testing
38510 - QUALIFICATION AND QUALITY CONFORMANCE TESTING

  • Each of the flows requires qualification and quality conformance testing.

  • The quality conformance testing frequency is defined in MIL-M-38510

  • (JAN product) and paragraph 1.2 of 883 (non-JAN product).

  • Quality conformance testing is divided into 5 groups, A, B, C, D

  • and E.

  • Group A : Sample electrical testing

  • Group B : Sample constructional tests

  • Group C : performed only on class B product. Sample reliability testing

  • Group D : Sample package related testing

  • Group E : Only required where a radiation hardness requirement identified.


Mil std 883 summary
MIL-STD-883 SUMMARY

  • 883 provides a valuable tool for the Military and Space semiconductor user.

  • However it does not provide the specific device electrical requirements necessary to achieve standardization.

  • This is established by MIL-M-38510


Mil m 38510
MIL-M-38510

  • Concurrent with the development of MIL-STD-883, RADC developed MIL-M-38510

  • MIL-M-38510, establishes the procedures which a manufacturer must follow to have his products listed in the Qualified Parts List

  • Also published a set of performance and electrical parameters, (slash sheets)


Obtaining qpl listing
OBTAINING QPL LISTING

  • A manufacturer must meet the following requirements before obtaining QPL listing

  • Line Certification as defined within MIL-STD 976

  • Device Qualification. There are two levels of QPL listing. Part II requirements are significantly less than Part I.

  • Part II listing was established to expedite manufacturers into the QPL.


Obtaining qpl listing cont
OBTAINING QPL LISTING (Cont.)

  • To obtain Part II listing, all line certifications must be complete and significant electrical, design and constructional test data submitted, and approved.

  • Part I listing requires significant additional testing and therefore takes much longer to complete.


Qualification by extension
QUALIFICATION BY EXTENSION

  • There are three ways to extend device or package qualification.

  • Die related testing

  • Die extension

  • Package extension

  • In addition it is possible to extend qualification to differing lead finishes.


Part numbering and marking
PART NUMBERING AND MARKING

  • MIL-M-38510 devices have a unique part numbering system.

  • e.g. JM38510/AAABBCDE:

  • J = JAN prefix

  • M38510 = MIL-M-38510

  • / = Replaced by hardness assurance letter, when

  • applicable


Part numbering and marking cont
PART NUMBERING AND MARKING (Cont)

  • AAA = Slash sheet no.

  • BB = Component no. on the slash sheet

  • C = Screening level S or B

  • D = Component package type.

  • E = Lead finish

  • e.g. JM38510/10107SGC = Slash sheet 101 device 07(LM118)

  • Class S, in 8 pin, TO-99 package with gold finish.


Mil i 38535
MIL-I-38535

  • Over the past decade, standards have not been able to keep pace with the rapidly changing technologies.

  • MIL-M-38510, which is very successful for simpler components was not suited to complex technologies such as ASICs, gate arrays and VLSI components.

  • As a result the Qualified Manufacturers List (QML) approach was implemented through MIL-I-38535

  • The QML approach is to qualify the manufacturer, rather than his specific products.


Mil i 38535 cont
MIL-I-38535 (Cont.)

  • The manufacturer adopts a Total Quality Management (TQM) approach to his business.

  • This applies from the initial design phase through to customer feedback.

  • The objective is to demonstrate, through Statistical Process Control (SPC), continuous improvement.


Mil s 19500
MIL-S-19500

  • To date the information related to the US-MIL System has related to ICs.

  • Similar reliability concerns are held with respect to other EEE components.

  • This section deals with discrete semiconductor devices, incl. FETs, bipolar transistors, diodes, rectifiers and thyristors.

  • In 1959 the United States Navy Bureau of Ships, created MIL-S-19500, which performs the same function for discrete semiconductor products, that MIL-M-38510 provides for ICs.

  • MIL-S-19500 was tailored to work with the JEDEC numbering system.


Mil s 19500 cont
MIL-S-19500 (Cont.)

  • The JEDEC numbering system is simple in that a three or four digit number was preceded by an XN, where X is one less than the number of active element terminations on the device.

  • Thus a diode has two terminations, X = 1.

  • Transistors generally have three terminations, thus X = 2

  • Dual transistors were also given a 2N number, even though their 6 pins would suggest a 5N number.

  • Suffixes were added to provide additional information e.g. M for matched pair.


Mil s 19500 cont1
MIL-S-19500 (Cont.)

  • In 1963 the Navy decided that it would be better to have a separate specification for detailed test methods.

  • In 1964 MIL-STD-750 was published as a “how to” of test methods for MIL-S-19500.

  • MIL-S-19500 establishes general requirements

  • Detailed requirements are specified in detail specifications.

  • 4 levels of PA requirements are specified.

  • JAN,JANTX,JANTXV and JANS.


Mil s 19500 qualification
MIL-S-19500 QUALIFICATION

  • Before any supplier can deliver any level of JAN semiconductor products, he must undergo a formal qualification cycle.

  • This qualification cycle is much like that already identified for MIL-M-38510.

  • Once qualified the manufacturer is listed in QPL-19500.

  • To retain QPL listing the manufacturer has to submit, each year, a summary of all of the quality conformance testing that has been completed.

  • If any changes are made to the QPL listed components that affect performance, quality, appearance, reliability or Interchangeability, re-qualification may be required.




Mil std 202
MIL-STD-202

  • MIL-STD-202 establishes uniform methods of testing for component parts including: Capacitors, resistors, switches, relays and transformers. The standard is only intended to apply to small parts.

  • The test methods have been prepared to serve several purposes:-

  • To give test results equivalent to those existing in actual service

  • To provide a standardized, uniform approach to testing

  • To provide a range of test methods, that can be applied to

  • components not covered by an approved military drawing


Mil std 202 cont
MIL-STD-202 (Cont.)

  • Classes of tests. The tests are divided into three classes:-

  • 101 to 199, Environmental

  • 201 to 299, Physical characteristics

  • 301 to 399, Electrical Characteristics


Mil std 202 cont1
MIL-STD-202 (Cont.)

  • Revision of test methods are indicated by a letter following the method number

  • Thus the first revision to test 101 is 101A, the second 101B etc.

  • Test sequences are not mandatory, but are provided to give guidance.



Component manufacturers specifications
COMPONENT MANUFACTURERS SPECIFICATIONS

  • Nearly all component manufacturers have their own internal standards which form the basis for any other customer specification placed upon them.

  • These standards cover basic electrical, mechanical and environmental characteristics.

  • Increasingly manufacturers are also setting standard screening and test requirements, from which they are not prepared to deviate.




Esa scc test and inspection requirements
ESA/SCC TEST AND INSPECTION REQUIREMENTS

  • This section covers the various tests and inspections which form part of the ESA/SCC Specification System for high reliability components.

  • In the ESA/SCC System the inspections are divided up into:

  • - Special In-process Controls

  • - Final Production Tests

  • - Burn-in

  • - Qualification Tests

  • - Lot Acceptance Tests



Special in process controls
SPECIAL IN-PROCESS CONTROLS

  • Special tests and inspections which are carried out during manufacturing with the intention of checking specific processing steps or sub-components of the final device.

  • These processing steps or sub-components are ones which have:

  • - Been shown to be critical in producing high reliability components and

  • - which cannot be tested or inspected at the end of production.


WLA

  • A wafer lot is a set of wafers that been manufactured together and therefore are from the same diffusion, oxidation and metallisation lot.

  • Wafer lot acceptance (WLA) is a series of inspections carried out on samples of die from a wafer lot. The samples must be taken from particular locations within the wafer. These positions are described in ESA/SCC Basic Specification No. 21400 or

  • MIL-STD-883 Method 5007.6


Sample selection
SAMPLE SELECTION

  • 1. Proper sample selection is an important part of the examination method.

  • 2. Statistical techniques using random selection are not practical, because of the large sample needed.

  • 3. Sample selection criteria are based on minimizing test sample size yet maintaining confidence in the examination.

  • 4. The selection of wafers is based on their position in the wafer holder. Dice at specific locations on those wafers are selected to show worst case metallisation processing defects.



Die sample examination
DIE SAMPLE EXAMINATION

  • 1. All four edge directions shall be examined for each type of contact window or metallisation step.

  • 2. Viewing angles & direction shall be chosen so as to accurately assess the quality of metallisation.

  • 3. For multi-layered-metal systems, it will be necessary to remove the layers one at a time to expose the next underlying layer for examination.





Acceptance rejection criteria
ACCEPTANCE/REJECTION CRITERIA

  • 1. Rejection of dice shall be based on lot process orientated defects.

  • 2. Rejection shall not be based on workmanship and other type defects such as scratches, smeared metallisation, tooling marks, etc. Such defects will be rejected at Pre-cap inspection.


Wla documentation
WLA DOCUMENTATION

  • 1. Photographic

  • - minimum of 3 SEM, 1 each for worst case metallisation, oxide step & contact window.

  • 2. Information traceable to each Photograph

  • - Manufacturer’s name & address

  • - name & address of test house or laboratory

  • - SEM operators/inspectors identification no.

  • - Date of SEM inspection & photograph

  • - component part, type or reference number

  • - SEM inspection lot number or code

  • - area forming subject of photograph

  • - magnification

  • - accelerating voltage

  • - viewing angle


Final production tests
FINAL PRODUCTION TESTS

  • The final step in the manufacture of most types of components is the final sealing of the component package. The Final Production Tests are a series of tests and inspections carried out just before and just after the components are sealed.

  • Purpose is to look for:

  • Anomalies in the production lot


Internal visual
INTERNAL VISUAL

  • Before sealing the component it should be examined optically to verify that internal materials, design and construction are in accordance with the applicable acquisition document.

  • In the case of integrated circuits the inspection should be performed at both high and low magnification.




Bond strength test
BOND STRENGTH TEST

  • This test measures bond strengths,evaluates bond strength distributions or determines compliance with specified bond strengths required of applied acquisition documents.

  • The specifications include table and graphs giving the different bond strengths required for the diameter and material of the bond wires.

  • A record should be made of the force at which the bond wire breaks and the applicable code for the site of break.







Die shear strength
DIE SHEAR STRENGTH

  • This test is used to determine the integrity of materials and procedures used to attach semiconductor die or surface mounted passive elements to package headers or other substrates.

  • Failure criteria is based on:

  • 1. Measure of force applied to die.

  • 2. Type of failure (if failure occurs)

  • 3. Visual appearance of residual die attach.



High temperature stabilisation bake
HIGH TEMPERATURE STABILISATION BAKE

  • Many components initially display variations in some of their electrical parameters, but these parameters become stable after a short time at high temperature.

  • The ESA/SCC Generic Specification No. 9000 requires devices to be stored for 48 hours at the maximum storage temperature.







Radiography
RADIOGRAPHY

  • The purpose of Radiography is, to confirm the following:-

  • Absence of foreign material within the package.

  • Correct location/mounting of internal elements.

  • Correctly made internal/external connections.

  • Proper sealing of the device.

  • Radiography has the following drawbacks:-

  • Aluminium bond wires and silicon are almost transparent to X-Rays

  • Additional tests are required to determine whether foreign material within the package is loose.

  • Due to unfavourable positioning of the device, a defect maybe undetectable


Fine leak testing
FINE LEAK TESTING

  • 1. The most widely used fine leak tests are radioactive tracer and helium leak detection methods

  • 2. The radioactive tracer test is most sensitive but test is complex and hazardous and the equipment is very expensive

  • 3. For the helium test the components are placed in a bombing chamber and pressurized in helium gas. The pressure and time are dependant on the volume of the package.

  • 4. The components are then transferred to a detector which detects the outgassing helium.





Gross leak testing
GROSS LEAK TESTING

  • 1. If the component needs to be preconditioned then it is placed in D80 perfluorinated fluid and placed in the bombing chamber under pressure for a specified amount of time.

  • 2. The component is then immersed in D02 perfluorinated fluid at 125°C. A stream of bubbles is looked for.

  • 3. Another gross leak test that is used in some circumstances i.e. for glass diodes is the dye penetrant test.

  • Here the component is placed in a dye penetrant fluid in the bombing chamber. After removal and cleaning it is inspected with ultraviolet light. Areas where the dye has entered inside cavities are easily located.




External visual inspection
EXTERNAL VISUAL INSPECTION

  • A low magnification inspection of the external surfaces of parts.

  • PURPOSE: “To check the external component materials, construction and workmanship for compliance to ESA/SCC”.

  • Requirements taken from ESA/SCC Basic Specification series 20500.

  • Performed after stress tests and as a final inspection prior to delivery. Generally the final inspection activity.

  • Can be performed on an AQL basis of 1% in final production tests. At other times, e.g. screening, it is performed on 100% basis. Although dimensional check is generally applied on AQL of 1%.



External visual inspection shall include the following examinations
EXTERNAL VISUAL INSPECTION SHALL INCLUDE THE FOLLOWING EXAMINATIONS

  • 1. Marking

  • 2. Metal Surface

  • 3. Case

  • 4. Feed-throughs

  • 5. Brazed joints

  • 6. Leads


External visual inspection requirements
EXTERNAL VISUAL INSPECTION REQUIREMENTS EXAMINATIONS

  • Ensure Material and External construction are in accordance with detail specification.

  • External surfaces should be clean.

  • No corrosion.

  • No peeling of finishes.

  • No holes or cracks.

  • No colour change.

  • Except for :Tinned surfaces which may show some discolouration after endurance or high temperature storage.

  • :Even discolouration of body after high temperature storage.


External visual inspection requirements cont
EXTERNAL VISUAL INSPECTION REQUIREMENTS (CONT.) EXAMINATIONS

  • Dimensional check - In accordance with the detail specification.

  • Marking - Legibility and permanence.

  • Soldered/Braised Joints - Reject if:

  • Solder surface not clean and smooth.

  • Evidence of cracks or voids.

  • Incomplete solder flow or coverage.

  • Balling of solder.

  • Foreign matter in solder.


Dimension check
DIMENSION CHECK EXAMINATIONS



Electrical screening tests
ELECTRICAL SCREENING TESTS EXAMINATIONS

  • Electrical measurements carried out to confirm that the components do meet the electrical requirements specified for them and to remove from the lot any which do not.

  • It is a check for any electrical degradation which has occurred in components as a result of any stress tests. The tests can be a full set of parameter measurements at room temperature, or at high and low temperature or just a measurement of certain critical parameters to look for changes.

  • The details of which measurements must be carried out at any point and what results are acceptable are given in the detail specification for each component type.


Burn in
BURN-IN EXAMINATIONS

  • The purposes of Burn-in are two fold:

  • - Removal of infant mortalities

  • - To check the PDA


High temperature reverse bias
HIGH TEMPERATURE REVERSE BIAS EXAMINATIONS

  • HTRB is designed to check the ability of a device to continuously block a voltage under conditions accelerated by both elevated temperatures and high voltages.

  • The HTRB is particularly useful when screening defective MOS devices. The primary failure modes for this stress are the leakage currents Idss and Igss.



Lot acceptance tests
LOT ACCEPTANCE TESTS EXAMINATIONS

  • Full ESA qualified parts undergo Lot Acceptance Testing (LAT) on samples from the production lot. This yields greater reliability assurance with respect to environmental, mechanical assembly and endurance of the devices. Within the ESA/SCC system the Lot Acceptance Tests are specified in Chart V of the appropriate Generic Specification and indicate which tests are performed, how many parts are required for each test and how many failures are permitted for each of the tests.


Constant acceleration
CONSTANT ACCELERATION EXAMINATIONS


High temperature storage
HIGH TEMPERATURE STORAGE EXAMINATIONS

  • The test is performed by placing the components in a high temperature chamber for the specified time at a specified temperature.

  • Its purpose is to determine whether the components are degraded by a period of time at their maximum rated storage temperature.

  • After completion of the storage test, any degradation of the components is detected by using appropriate end point measurements such as leak testing, electrical testing and visual inspection.


Mechanical shock test
MECHANICAL SHOCK TEST EXAMINATIONS

  • The components are mounted on a shock machine and subjected to a series of mechanical shocks.

  • The purpose of this test is to check the mechanical integrity of the package, particularly the die mounting, wire bonding and package sealing.


Vibration test
VIBRATION TEST EXAMINATIONS


Vibration test1
VIBRATION TEST EXAMINATIONS


Thermal shock
THERMAL SHOCK EXAMINATIONS

  • Components are alternately immersed in liquids at high temperature and at low temperature.

  • The number of cycles, the immersion and transfer times, the liquids to be used and the temperatures to be used are given in the appropriate specifications.

  • The purpose of the test is to subject the components to severe thermal stressing to reveal any mechanical weaknesses.

  • Any degradation caused by this test is usually detected by subsequent end point measurements such as leak testing, electrical measurements or external visual inspection.


Moisture resistance
MOISTURE RESISTANCE EXAMINATIONS

  • Components are subjected to a number of cycles of combined high temperature and humidity.

  • Purpose of the test:

  • Corrosion

  • - Moisture ingress.


Operating life
OPERATING LIFE EXAMINATIONS

  • The components are electrically stressed while simultaneously subjected to a high temperature.

  • → accelerated ageing

  • → simulating the normal operating life in a matter of weeks.

  • Arrhenius Equation: R=Ae -Eα/kT

  • Electrical measurements, leak testing, visual inspection performed at the end of the test to establish whether there is any degradation.





Solderability
SOLDERABILITY EXAMINATIONS

  • This test method is to evaluate the The ability of the terminations to be:

  • 1. Wetted by a coating of solder.

  • 2. To produce a suitable solder fillet.

  • The termination is dipped in flux and allowed to dry for a few seconds, then dipped in a solder pot which is at the specified temperature for 7 - 10 secs. The termination is then cleaned in IPA and examined at a magnification of 10-15x.


Solderability1
SOLDERABILITY EXAMINATIONS

  • Acceptance criteria:

  • 1. At least 95% covered with a continuous new solder coating.

  • 2. Pinholes, voids, porosity, nonwetting, or dewetting must not exceed 5% of the total area.


Solderability2
SOLDERABILITY EXAMINATIONS


Solderability3
SOLDERABILITY EXAMINATIONS


Lead integrity
LEAD INTEGRITY EXAMINATIONS

  • There are various tests for determining the integrity of device leads, welds and seals.

  • 1. Straight tensile loading.

  • 2. Application of bending stresses.

  • 3. Application of torque or twisting stresses.

  • 4.Application of peel and tensile stresses

  • The individual test conditions need to be specified.


Lead integrity1
LEAD INTEGRITY EXAMINATIONS

  • Failure criteria:

  • The components should be examined at a magnification of 10 – 20x after the removal of stress any evidence of:

  • 1. Breakage

  • 2. Loosening

  • 3. Relative motion between lead and body

  • 4. Adhesion failure of solder pads

  • shall be considered a failure.


Lead integrity2
LEAD INTEGRITY EXAMINATIONS


Microsection
MICROSECTION EXAMINATIONS

  • Components are microsectioned after potting in a suitable epoxy resin so that a microscopic examination can be undertaken for the purpose of accurately locating, identifying and characterising all the internal structural features of the samples in order to judge any defects against the criteria of the specification.

  • Typical components that require microsection are:

  • Diodes

  • Capacitors

  • Relays

  • Isolators

  • Fuses



Esa scc escc
ESA/SCC EXAMINATIONS→ ESCC

  • Following a SCAHC recommendation produced after consultation with the space industry, ESCC Specifications are being phased in to replace the ESA/SCC specifications.

  • The ESA/SCC Generic Specifications contain five charts which are:-

  • Chart I Testing Levels

  • Chart II Final Production Tests

  • Chart III Burn-in and Electrical Measurements

  • Chart IV Qualification Tests

  • Chart V Lot Acceptance Tests

  • In ESCC Generic specifications, these will be replaced by:-

  • Chart F1 General Flow Chart

  • Chart F2 Screening Tests Chart

  • Chart F3 Qualification and Periodic Tests



Procurement system selection
PROCUREMENT SYSTEM SELECTION EXAMINATIONS

  • Generally, on Larger programmes, the prime contractor selects the method by which the EEE components will be procured. The basis for the selection will depend upon the programme cost, meeting the agreed schedule, and compliance to the technical requirements.

  • Procurement possibilities are usually assessed under three separate headings:

  • - Self Procurement

  • Co-ordinated Procurement

  • Centralised Procurement


Self procurement
SELF PROCUREMENT EXAMINATIONS

  • Overall higher costs:

  • No cost sharing between contractors

  • MOQs

  • More man power required


Coordinated procurement
COORDINATED PROCUREMENT EXAMINATIONS

  • Minimum:

  • Loose association of users combining procurements

  • Maximum:

  • Almost Centralised were all parts are procured through the same system to the same specifications.

  • Control is in theory maintained by the prime contractor who would receive schedules, specifications, non-conformances evaluation reports and other technical input from users.


Centralised procurement
CENTRALISED PROCUREMENT EXAMINATIONS

  • All EEE component requirements are delivered to the Prime contractors managements team who then consolidate the requirements into a project procurement allocation list, which once reviewed and approved by the Procurement Management is passed to the Procurement agent to carry out the actual procurement.

  • If properly managed Centralised procurement offers:

  • - All the advantages of minimal cost

  • - Maximised control and uniform quality





Procurement phases
PROCUREMENT PHASES EXAMINATIONS

  • PRE-PROCUREMENT: Those activities necessary to be completed before purchase orders can be placed upon the component manufacturers.

  • PROCUREMENT: The actual manufacture, test and inspections necessary to meet the purchase order requirements.

  • POST PROCUREMENT: Those activities required to provide confidence that the requirements have been met and to prepare the components for installation.



Pre procurement phase
PRE-PROCUREMENT PHASE EXAMINATIONS

  • The objective of this phase is to complete those activities necessary to confidently place purchase orders for EEE components.

  • Often this phase is not properly carried out, leading to severe problems and project delays later in the programme.

  • Those areas most commonly neglected are:-

  • Risk Management

  • Component Selection

  • Component Type Reduction.

  • Evaluation.

  • Obsolescence Management

  • Specification preparation, integration and modification.



Component selection
COMPONENT SELECTION EXAMINATIONS

  • The equipment design engineers are responsible for the selection of EEE components. However it is the task of the component engineers to provide support and assistance in the activity, particularly with respect to standardization, quality and reliability issues.

  • The main tool provided to assist in the selection process is the Preferred Parts List (PPL).


The european preferred parts list
THE EUROPEAN PREFERRED PARTS LIST EXAMINATIONS

  • ECSS-Q-60-01 provides the rules for establishing the list of preferred and suitable components to be used by European manufacturers of spacecraft hardware and associated equipment.

  • A copy of the ECSS-Q-60-01 can be down loaded from the ECSS home page (http://www.ecss.nl/)

  • The EPPL can be found on the ESCIES website.


Eppl cont
EPPL (CONT.) EXAMINATIONS


Eppl cont1
EPPL (CONT.) EXAMINATIONS


Eppl cont2
EPPL (CONT.) EXAMINATIONS


Eppl cont3
EPPL (CONT.) EXAMINATIONS


Eppl cont4
EPPL (CONT.) EXAMINATIONS


Ppl cont
PPL (CONT.) EXAMINATIONS

  • Contractual enforcement of the PPL has sometimes been achieved, however this places a major responsibility upon the PPL developer to ensure that the components in the PPL are:-

  • Capable of satisfying a wide range of design applications

  • Mature in the chosen technologies to be suitable for flight

  • applications

  • Considered to have a significant utilization

  • Have an acceptable test or usage history

  • Available from approved manufacturers


Ppl cont1
PPL (CONT.) EXAMINATIONS

  • In addition to the above it is also essential that the PPL also:-

  • Takes into account known single user applications

  • Identifies new technologies for evaluation (Part 2)

  • Is maintained and regularly updated


QML EXAMINATIONS


Qml cont
QML (CONT.) EXAMINATIONS


Qml cont1
QML (CONT.) EXAMINATIONS


Parts list review
PARTS LIST REVIEW EXAMINATIONS

  • Parts list should be reviewed to check:

  • Availability of qualified parts.

  • Lead times to component delivery.

  • Part costs and minimum order quantities (MOQ)

  • Part type reductions (with implicit per part cost reductions for buying greater quantities of a given type)

  • Number of DPAs necessary - Does the EEE parts plan allow limited DPA on similar part types / date codes

  • Radiation test requirements

  • LAT levels necessary

  • The need for any constructional analyses

  • Evaluation plans (life test etc.)



PEMs EXAMINATIONS

  • Space projects are increasingly interested in using PEMs.

  • There are a number of reliability related issues with using COTS PEMs for space including:

  • Traceability

  • Lot Conformance

  • Screening

  • Change Control

  • Radiation Hardness

  • Obsolescence


Screening tests
SCREENING TESTS EXAMINATIONS

  • There are a number of tests that can be performed to increase confidence in device reliability.

  • Some procurement agents believe that minimal screening is necessary and that over and above the usual screening requirements it is necessary to perform little more than:

  • Radiographic Inspection

  • Scanning Acoustic Microscopy (CSAM)







PEMs EXAMINATIONS

  • But…

  • There are other failure mechanisms and potential concerns.


Tg of pem plastics
Tg of PEM PLASTICS EXAMINATIONS


Screening
Screening EXAMINATIONS

  • If you need confidence approaching that which you might have from space qualified parts you’ll need to look at performing…

  • DPA including Tg (Sample)

  • 1st Electrical Test (100%)

  • Temperature Cycling (Sample)

  • Radiographic (100%)

  • CSAM (100%)

  • Electrical Test (100%)

  • Dynamic Burn-In (100%)

  • Electrical Test (100%)

  • Dynamic Life Test (Sample)

  • End Point Electrical Test(100%)

  • HAST (Sample)

  • Post HAST electrical Test (Sample)

  • Vibration (Sample)


Cost impact of upscreening
COST IMPACT OF UPSCREENING EXAMINATIONS

  • NEPAG have produced a cost model to assess the relative costs of buying space grade parts with the cost of upscreening COTS.

  • The model does not include non-recurring engineering (NRE) charges so the model is very conservative. NRE can run to hundreds of thousands of dollars for complex microcircuits.



Reliability assurance levels
RELIABILITY ASSURANCE LEVELS EXAMINATIONS

  • NASA has traditionally categorized space level EEE parts by reliability assurance level:

  • Level 1 = Most reliable, intended for use in mission critical and life support applications (US MIL Class S, V or K or ESA Level B LAT2)

  • Level 2 = Moderate reliability for general applications (US MIL Class B,Q or H or ESA Level C)

  • Level 3 = Non-mission essential, higher risk applications (MIL-STD-883 Compliant)



Radiation assurance
RADIATION ASSURANCE EXAMINATIONS

  • COTS parts are not designed or manufactured to meet any particular level of radiation hardness for TID or SEE.

  • Radiation is a very real issue with plastic devices because plastic is an insulator and may allow charge to build up.

  • Radiation Hardness Assurance a must be performed on every lot further adding to the overall cost.

  • The lack of lot homogeneity for COTS may require testing of larger samples also driving up costs.


Conclusion
CONCLUSION EXAMINATIONS

  • COTS microcircuits are not a low cost alternative to inherently space level parts.


To find out more
To find out more… EXAMINATIONS

  • NEPAG Website:

  • http://eee.larc.nasa.gov/forum/default_2.htm

  • Mike Sampson’s paper to ESCCON 2002:

  • https://escies.org/private/esccon2002/coasscopro.html


Plastic decapsulation
PLASTIC DECAPSULATION EXAMINATIONS


Plastic decapsulation1
PLASTIC DECAPSULATION EXAMINATIONS


Type reduction
TYPE REDUCTION EXAMINATIONS

  • Type reduction is carried out to minimize the number of component types with similar functions.

  • Failure to carry out this activity reduces the possibility to standardize.

  • This, in turn, results in significant cost increases and increased delivery times.

  • It is the component engineers responsibility to ensure that this task is carried out thoroughly.


Component evaluation
COMPONENT EVALUATION EXAMINATIONS

  • ECSS-Q-60A states. If valid and acceptable qualification of a component type cannot be demonstrated, a component evaluation and approval testing programme shall be implemented.

  • This programme is required to cover the following elements:-

  • - Design and Application Assessment

  • - Constructional Analysis

  • - Manufacturer Assessment

  • - Evaluation Testing

  • Reduction or omission of any of the above steps may be approved if sufficient evidence is provided to justify the omission.


Design and application assessment
DESIGN AND APPLICATION ASSESSMENT EXAMINATIONS

  • The objective of the Design and Application assessment is to:-

  • Identify those electrical parameters essential for the intended

  • application

  • Justify why a fully qualified component cannot be used


Constructional analysis
CONSTRUCTIONAL ANALYSIS EXAMINATIONS

  • Typically carried out on a sample of three representative components, the Constructional Analysis is intended to demonstrate that:-

  • The standard of fabrication and assembly has been fully assessed.

  • All potential failure modes are identified.

  • No materials or processes have been employed which might result

  • in premature failure of the component.


Typical constructional analysis flow
TYPICAL CONSTRUCTIONAL ANALYSIS FLOW EXAMINATIONS

6 OF, SAMPLES

PHYSICAL DIMENSIONS

ELECTRICAL MEASUREMENTS

EXTERNAL VISUAL INSPECTION

HERMETICITY

MARKING AND SERIALISATION

X - RAY

DE - CAPPING

INTERNAL VISUAL INSPECTION

MICROSECTIONING

BOND STRENGTH TEST

DIE SHEAR TEST


Manufacturer assessment
MANUFACTURER ASSESSMENT EXAMINATIONS

  • This assessment, carried out against the appropriate ESA/SCC checklist, includes, but is not necessarily limited to, an audit of:-

  • The overall manufacturing facility, and its organization and

  • management.

  • The manufacturers system for inspection and manufacturing

  • control.

  • The production line used for the component.


Specification writing
SPECIFICATION WRITING EXAMINATIONS

  • Maximum use should always be made of existing specifications

  • But, projects sometimes require devices which:

  • There is no existing hi-rel specification

  • Require additional testing

  • Testing is excessive


Specification writing1
SPECIFICATION WRITING EXAMINATIONS

  • If the required parts fall outside of existing qualification limits they can be covered by extension and a cover sheet is all that is required.

  • Specifications are prepared around the manufacturers datasheet and sent to the manufacturer see whether the requirements are possible and to the customer for agreement on the details. This cycle of negotiation continues until full agreement is reached.

  • Specifications are usually written in the same format as some existing specification such as those from MIL or ESA. It is necessary to establish which type of format is most desirable to the customer.


Obtaining specifications
OBTAINING SPECIFICATIONS EXAMINATIONS

  • Most space specifications are available free of charge through the internet.

  • The following sites may prove useful:

  • ESA Specifications:

  • http//www.escies.org

  • US Military Specifications:

  • http://www.dscc.dla.mil/programs/milspec/default.asp

  • Military and others (J-STD, IEC etc.)

  • http://astimage.daps.dla.mil/online/new/


Evaluation testing
EVALUATION TESTING EXAMINATIONS

  • Carried out after completion of the previously identified assessments, evaluation testing is intended to determine which inspection and tests are the most appropriate to provide confidence that the component when fully meeting the procurement specification requirements, will also meet the intended mission requirements.

  • The types of testing to be considered include:-

  • Electrical stress

  • Mechanical stress

  • Environmental stress

  • Assembly capability testing

  • Radiation testing


Evaluation report
EVALUATION REPORT EXAMINATIONS

  • The Evaluation Report comprises:-

  • Design Assessment

  • Constructional Analysis

  • Manufacturer Audit

  • Evaluation test report


Part approval documents pad
PART APPROVAL DOCUMENTS (PAD) EXAMINATIONS

  • Once the Pre-procurement technical activities are complete, it is of great value, and mandatory for ESA programmes to summarize the technical baseline.

  • The Part Approval Document (PAD), provides an excellent base for this summary.



Attrition and spares
ATTRITION AND SPARES EXAMINATIONS

  • Allowance must be made for the provision of attrition and spares, the following excerpt from a procurement plan is an example of such a policy:-


Obsolescence management
OBSOLESCENCE MANAGEMENT EXAMINATIONS

  • How can we minimise the affects of obsolescence?

  • At the design phase the selection of the components must have the maximum predictable life span.

  • Procure sufficient components for the intended programme and any envisaged ‘follow on’ programmes

  • Monitor the availability of components used in the design and allow the implementation of ‘last time buy’

  • Joining obsolescence groups can yield opportunities to discuss ‘work around solutions’ with other engineers


Obsolescence management cont
OBSOLESCENCE MANAGEMENT (CONT.) EXAMINATIONS

  • There are manufacturers who specialise in buying die stock from manufacturers who are phasing out product types.

  • Assembly and Test Houses can package and screen product if die is available.



Risk management concept
RISK MANAGEMENT CONCEPT EXAMINATIONS

  • Risk management is a four step systematic and iterative process for optimising resources in accordance with the project’s risk management policy.

  • Four Steps:

  • Step1 - Define risk management implementation requirements

  • Step2 - Identify and assess the risks

  • Step 3 - Decide and act

  • Step 4 - Monitor, communicate and accept risks


Step 1 define risk management implementation requirements severity consequence scoring scheme
STEP 1 – DEFINE RISK MANAGEMENT IMPLEMENTATION REQUIREMENTSSEVERITY CONSEQUENCE SCORING SCHEME


Step 1 define risk management implementation requirements likelihood scoring scheme
STEP 1 – DEFINE RISK MANAGEMENT IMPLEMENTATION REQUIREMENTSLIKELIHOOD SCORING SCHEME



Step 2 identify and assess risks
STEP 2: IDENTIFY AND ASSESS RISKS REQUIREMENTS

  • Purpose:

  • To identify each of the risk scenarios, to determine based on the output of step 1, the magnitude of the individual risks and finally, to rank them. Data from all project domains are used (managerial, programmatic, technical)


Step 3 decide and act
STEP 3: DECIDE AND ACT REQUIREMENTS

  • Purpose:

  • To analyse the acceptability of risks and risk reduction options according to the risk management policy, and to determine the appropriate risk reduction strategy.

  • Determine measures for reducing the risk

  • Determine the risk reduction success/failure criteria.

  • Select the best risk reduction measure


Step 4 monitor communicate and accecpt
STEP 4:MONITOR, COMMUNICATE AND ACCECPT REQUIREMENTS

  • Purpose:

  • To track, monitor, update, iterate and communicate risks and finally to accept the risks.

  • Periodic assessment of risks

  • Illustration of risk trend over project evolution

  • Implementation of new risks as they arise or become evident




The purchase order
THE PURCHASE ORDER REQUIREMENTS



Planning of inspections
PLANNING OF INSPECTIONS REQUIREMENTS

  • Ensure that the manufacturer knows that you are coming and that he is aware of the exact purpose of the of the inspection

  • Check that all essential documents are available.

  • If previous history files are available, check for previous problems found and how they were dealt with. It is important to be as knowledgeable as possible.


Documentary order of precedance
DOCUMENTARY ORDER OF PRECEDANCE REQUIREMENTS

  • To undertake an inspection the procurers inspector should use the following documentation. Whilst undertaking an inspection it is possible that conflicts between documents could occur. In such circumstances the procurer’s inspector shall take the documentary order of precedence as indicated below:-

  • Purchase order or contract

  • Detail Specification

  • Generic Specification

  • Basic Specification

  • Other reference documents


Sample inspection
SAMPLE INSPECTION REQUIREMENTS

  • Within the ESA/SCC System sampling inspection is performed for certain tests.

  • Three approaches may be found within the system:-

  • Fixed sample size

  • Sample size dependent upon lot size, and used to assess the lot on an AQL

  • Sample size dependent on lot size and used to assess the lot based upon an LTPD

  • Use of sampling methods is of limited statistical significance due to discontinuous nature of space component production.


Sample inspection cont
SAMPLE INSPECTION (CONT.) REQUIREMENTS

  • Acceptable Quality Level (AQL), example

  • ESA/SCC Detail specification 5101/011

  • Electrical measurements at high temperature

  • Tests to be performed on a sample basis, Inspection Level II, Table II-a, AQL = 1.0 of MIL-STD-105, minimum 10% parts to be measured.

  • Using MIL-STD-105 , lot size 450, inspection level II requires sample size letter H, Now, using the ‘Single Sampling Plan for Normal Inspection’

  • code H and AQL 1.0%, gives sample 50 accept on 1, fail on 2.


Sample inspection cont1
SAMPLE INSPECTION (CONT.) REQUIREMENTS

  • Lot Tolerant Percentage Defects. (LTPD) Example.

  • Electrical measurements at room temp. on 450 2N6033 Transistors

  • ESA/SCC 5203/026 a.c. parameters sample basis LTPD 7 or less.

  • Using LTPD sampling plan, lot sizes greater than 200, LTPD 7 or less,

  • The sample size is to be a reasonable size for the lot under inspection. e.g. Sample size 32 accept on 0 defects.

  • Sample size 55 accept on 1 defect

  • Summary LTPD = 7

  • Sample size = 32

  • Acceptance no. = 0

  • Rejection no. = 1


Inspections summary
INSPECTIONS SUMMARY REQUIREMENTS

  • Inspect strictly in accordance with the requirements

  • Do not allow personal feelings, lack of time or previous history affect your judgement.

  • Report your findings in reasonable detail .

  • Never try to correct a discrepancy, raise a non-conformance.

  • Always report the sampling plan used.

  • Obtain the manufacturers representatives signature to your report.

  • Never lose your temper.

  • If you cause any damage, of any sort, report it immediately.


Qualification testing
QUALIFICATION TESTING REQUIREMENTS

  • Qualification Testing of a component must be in accordance with Chart IV of the relevant ESA/SCC Generic Specification.

  • The Qualifying Space Agency may accept relevant and recent valid test data as replacing part, or all, of the Chart IV test requirements.

  • Components subjected to the qualification testing phase are considered as having undergone destructive testing.

  • The disposition of the qualification test lot is the responsibility of the Qualifying Space Agency.


Typical final production and burn in tests

FINAL PRODUCTION TESTS REQUIREMENTS

(Ref. ESA / SCC 9000 Chart II) (For Integrated Circuits)

BURN-IN AND ELECTRICAL MEASUREMENTS

(Ref. ESA / SCC 9000 Chart II) (For Integrated Circuits)

TYPICAL FINAL PRODUCTION AND BURN-IN TESTS

Productions and Controls in accordance with Section 5 of the Generic Specification

Parameter Drift Values (Initial Measurements)

Internal Visual Inspection

Power Burn-in

Special In-Process Tests

Parameter Drift Values (Final Measurements)

Final Assembly, Encapsulation

Stabilisation Bake

Electrical Measurement at High and Low Temperature

Mechanical + Environmental Tests

Electrical Measurement at Room Temperature

Seal Test (optional)

Radiographic Inspection

Electrical Measurement at Room Temperature

Seal Test (Fine and Gross Leak)

Electrical Measurement at High and Low Temperature (optional)

External Visual Inspection

Marking (plus serialisation for Level B)

Check for Lot Failure (P.D.A.)

External Visual Inspection Sampling Level II - A.Q.L. 1%)

To Figure 9

Dimension Check


Typical generic specification qualification test
TYPICAL GENERIC SPECIFICATION QUALIFICATION TEST REQUIREMENTS

100 Components

Environmental / Mechanical Subgroups nnn

Assembly / Capability Subgroups

Endurance Subgroup nnnnnnnnnnninnn

15 Components

15 Components

15 Components

15 Components

15 Components

Shock Test

Temperature Cycling

Solderabilty

Operating Life

High Temperature Storage

Vibration nnnnnnnnnnn

Thermal Shocknnnnn

Permanence of Marking

Electrical Measurements during Endurance Testing

Electrical Measurements during Endurance Testing

Seal Test nnn

Constant Acceleration

Moisture Resistance

Terminal Strength

Seal Test

Seal Test

Seal Test

External Visual Inspection

Electrical Measurements at Room Temperature

Electrical Measurements at Room Temperature

Internal Visual Inspection

External Visual Inspection

External Visual Inspection

Bond Strength(1)

External Visual Inspection

External Visual Inspection

Die Shear(1)

2

2

1

1

1

2

1

3


Incoming inspection
INCOMING INSPECTION REQUIREMENTS

  • Once the devices arrives at the procurement agent. A Receiving Inspection Record (RIR) is produced which details of the purchase order, manufacturer, the procurement specification , lot numbers, date codes etc.

  • The RIR also records:

  • Package inspection

  • Parts Inspection

  • Data Review

  • DPA Allocation

  • Comments, observations, NCRs etc are recorded on the RIR


Data review
DATA REVIEW REQUIREMENTS


DPA REQUIREMENTS

  • The objective of DPA is to provide an engineering evaluation of a device lot to determine compliance with specified constructional requirements, evaluate processes, workmanship and the material consistency of the product.

  • The sample size is not statistically relevant but is intended to be a snapshot of the quality of the lot.

  • A typical sample size is 3 randomly selected pieces but it can be dependant on factors such as cost, quantity of lot and customer requirements.


Dpa data records
DPA DATA RECORDS REQUIREMENTS

  • Each DPA should be assigned a unique number for identification purposes and each component serialized if it has not been already.

  • DPA data records should include:

  • 1. Outline of the DPA procedure.

  • 2. DPA summary sheet.

  • 3. DPA check list.

  • 4. DPA data sheets.

  • 5. Original X-rays and photographs

  • 6. Other data or analysis results which support findings


Component types for dpa
COMPONENT TYPES FOR DPA REQUIREMENTS

DPA is required to be performed on samples from each delivered date code of the types listed below:

Discrete semiconductors

Integrated circuits

Filters

Variable capacitors/resistors

Ceramic capacitors

Tantalum capacitors

Relays and switches

Crystals

Hybrids

High voltage components

High frequency components

Opto-electronic components


Example dpa flow for an integrated circuit
EXAMPLE DPA FLOW FOR AN INTEGRATED CIRCUIT REQUIREMENTS

  • External visual MIL-STD-883 method 2009.7

  • Mechanical parameters Manufacturers data sheet

  • Fine leak MIL-STD-883 method 1014.7 cond A1

  • Gross leak MIL-STD-883 method 1014.7 cond C

  • Radiographic MIL-STD-883 method 2012

  • PIND MIL-STD-883 method 2020

  • Marking permanence ESA/SCC 24800

  • Lead integrity MIL-STD-883 method 2004.5 cond B2

  • Solderability MIL-STD-883 method 2003.4

  • Internal visual MIL-STD- 883 method 2010.8 cond A

  • SEM inspection MIL-STD-883 method 2018.3

  • Wire bond strength MIL-STD-883 method 2011.5 cond D

  • Die shear strength MIL-STD-883 method 2019.5


Example dpa flow for a diode
EXAMPLE DPA FLOW FOR A DIODE REQUIREMENTS

External visual MIL-STD-750 method 2071.4

Mechanical parameters MIL-PRF-19500/***

Marking permanency ESA/SCC 24800

Solderability MIL-STD-750 method 2026

Internal visual MIL-STD-750 method 2074.3

Microsection MIL-STD-750 method 2074.3


Non conformance control
NON CONFORMANCE CONTROL REQUIREMENTS

  • The European Space Agency has a very precise way of dealing with non conforming product and if it is an ESA project that is being worked upon then it is a requirement that the ESA/SCC approach to NCRs is followed. This is defined in ESA/SCC 22800

  • Many companies consider this to be too rigid and adopt a more relaxed approach.


Initiation of the esa scc non conformance system
INITIATION OF THE ESA/SCC NON-CONFORMANCE SYSTEM REQUIREMENTS

  • There are two distinct ways of initiating the ESA/SCC Non-Conformance System:-

  • • The Chief Inspector of the ESA/SCC qualified manufacturers,

  • • The user of the ESA/SCC Specification System,

  • The former is not only required to initiate the Non-Conformance System but also to take responsibility for the initiation of the system for any non-conformance brought to their attention from any source.

  • The latter also have a major responsibility toward the system, in that they are users of the ESA/SCC System.


The manufacturer s chief inspector
THE MANUFACTURER'S CHIEF INSPECTOR REQUIREMENTS

  • There are clearly defined occasions when the Manufacturer's Chief Inspector must initiate the non-conformance procedure, i.e.:-

  • • During final production tests.

  • • As a result of a PDA failure

  • • As a result of Qualification failure

  • • As a result of LAT failure.


The esa scc system users
THE ESA/SCC SYSTEM USERS REQUIREMENTS

  • Any person in attendance at an ESA/SCC Qualified Manufacturer's premises to conduct or witness a test or inspection on ESA/SCC qualified component lots will raise a NCCS on finding the following:

  • • Any serious breach of quality or safety procedures.

  • • Clear evidence that the Process Identification Document (PID) has been modified without ESA/SCC approval.

  • • Evidence that the lot submitted for inspection does not originate from the master lot identified.

  • • Should the manufacturer refuse to accept the rejection of any defects found.


The esa scc system users continued
THE ESA/SCC SYSTEM USERS (Continued) REQUIREMENTS

  • • If any data to be reviewed is incomplete, inaccurate, or results in rejection of the data.

  • • Once components have been delivered by the component manufacturer to the orderer, the ESA/SCC Non-Conformance System, as defined within ESA/SCC 22800, shall continue to be applied.


Flow diagram of non conformance procedure
FLOW DIAGRAM OF NON-CONFORMANCE PROCEDURE REQUIREMENTS

NON-CONFORMANCE

1

2

LEVEL DETERMINATION

Telex Notification to ESA / SCC

Lot Rejection

LOCAL MRB Decision

ESA / SCC MRB Decision:

• Reject from Lot • Rework • Use”as is” (waiver)

ESA / SCC Documentation Affected

Initiate D.C.R. nn

Corrective Action

D.C.R. decision by SCCG

NO

Distribution

Distribution

YES

Corrective Actions

Reject

NC Closed

NCR Closed

Review of Qualification Status by SCCG

File in Qualification Report

ESA / SCC QPL


Non conformance procedures

NON-CONFORMANCE PROCEDURES REQUIREMENTS

All non-conformances are notified to a Materials Review Board, by means of a Non-Conformance Control Sheet.

The Non-Conformance Control Sheet initially details the details of the non-conformance and, later, analysis of the failure, the MRB decision and confirmation that all necessary actions have been carried to their conclusion.


Non conformance levels
NON-CONFORMANCE LEVELS REQUIREMENTS

  • There are two levels of Non-Conformance:

  • LEVEL 1: MINOR - Any departure from the requirements which can be corrected and will not contravene ESA/SCC documentation.

  • MINOR Non-Conformances result in Local Material Review Boards (MRB).

  • LEVEL 2: MAJOR - All other Non-Conformances.

  • MAJOR Non-Conformances result in ESA/SCC Material Review Boards (MRB).


Local mrb
LOCAL MRB REQUIREMENTS

  • Local MRB shall be composed, as a minimum, of the following persons:-

  • • Chief Inspector of the manufacturer (Chairman)

  • • National Space Agency representative

  • • Responsible engineer of the manufacturer

  • • Representative of the Orderer (in the case of procurement)

  • Members of the MRB may call in specialists as required, but they shall not have voting rights.


Local mrb cont
LOCAL MRB (CONT.) REQUIREMENTS

  • In determining the disposition and corrective action to be taken, the

  • board shall:

  • • Take all necessary action to investigate the causes of the

  • non-conformance.

  • • Review the records of previous actions applicable to similar or identical cases.

  • • Consider the recommendations of specialists acting in an advisory capacity.

  • • Initiate failure analysis of failed items, if appropriate.

  • • Consider and record the effects of the non- conformance on contractual requirements.


Esa scc mrb
ESA/SCC MRB REQUIREMENTS

  • The ESA/SCC MRB shall be composed, as a minimum, of the following persons:-

  • • National Space Agency representative (Chairman)

  • • Chief Inspector of the manufacturer

  • • Qualification Manager of the manufacturer

  • • ESA/SCC Representative having acceptance authority

  • • Representative of the Orderer (if applicable)

  • Members of the ESA/SCC MRB may call in specialists as required, but these shall have no voting rights.


Nccs resolution cont
NCCS RESOLUTION (CONT.) REQUIREMENTS

  • ACTIONS

  • • Disposition for corrective action,

  • • Disposition of the actual product that is the subject of the non-conformance (e.g. whether or not it can be of further use),

  • • Any preventive measures taken.

  • Decisions of the MRB must be unanimous.


Nccs close out
NCCS CLOSE-OUT REQUIREMENTS

  • The last two lines on the NCCS allow for the confirmation and verification of the implementation of the MRB disposition.

  • The NSA Inspector and the Chief Inspector shall ensure, through actual inspection, that all actions are completed. Close-out requires that, as a minimum:-

  • • Corrective actions have been accomplished.

  • • The effectiveness of preventive actions has been proven.

  • • The necessary design or documentation changes have been accomplished and verified by tests if so decided by the MRB.

  • • Preventive actions have been taken also in respect of identical material.

  • • The NCCS is signed off by the Chief Inspector and the NSA Inspector to evidence the technical review and completion of all actions decided upon by the MRB.


Non conformance control sheet distribution
NON-CONFORMANCE CONTROL SHEET DISTRIBUTION REQUIREMENTS

  • Copies are to be sent members of the relevant MRB immediately the “Identification” and “Description” sections have been completed by the Chief Inspector.

  • In urgent cases, a fax or e-mail is recommended.

  • After close-out by the MRB the NSA Inspector is responsible for defining the distribution list and for its distribution.


Distribution of non conformance control sheet cont
DISTRIBUTION OF NON-CONFORMANCE CONTROL SHEET (CONT.) REQUIREMENTS

  • For both non-conformance levels, the standard distribution list shall include as a minimum:-

  • • The Chief Inspector of the Manufacturer.

  • • The Qualification Manager of the manufacturer.

  • • The National Space Agency representative concerned.

  • • ESA/SCC (level 1, for information only).

  • • The National Space Agency concerned for incorporation in the qualification report (but only after “close-out”).

  • • the Orderer (in case of procurement).

  • • other persons concerned.



Ncr spur s approach
NCR – SPUR’S APPROACH REQUIREMENTS

  • 1) The NCR is raised as soon as the non conformance is discovered with all the necessary details including which part of the procurement specification the non conformity applies to.

  • 2) The report is then sent to the customer and negotiation between customer and supplier is entered into. An MRB is called if it is considered necessary.

  • 3)The NCR is closed out once a decision is reached to whether they are to accept the components.

  • For the component supplier it is important that all NCRs are assigned unique numbers and kept in a log along with any written agreements between the supplier and the customer.

  • Copies of the NCRs must then accompany the components to the customer.


Esa alert system
ESA ALERT SYSTEM REQUIREMENTS

  • The ESA Alert system was launched in December 1995.

  • This system is aimed at providing awareness of failures and problems experienced in space projects, in order to eliminate or minimise their impacts and prevent their recurrence in current and future projects..

  • The ESA Alert System and its implementation procedure is fully described within Q/EAS/PROC/1

  • Details of how to receive ESA Alerts can also be found via the ESCIES website (www.escies.org) or go directly to: http://www.estec.esa.nl/qq/alerts


Esa alert system1
ESA ALERT SYSTEM REQUIREMENTS


Esa alert system2
ESA ALERT SYSTEM REQUIREMENTS


Esa alert system3
ESA ALERT SYSTEM REQUIREMENTS


Esa alert system4
ESA ALERT SYSTEM REQUIREMENTS



Component relifing
COMPONENT RELIFING REQUIREMENTS

If a EEE component has exceeded its shelf life a relifing procedure can be used validate an extension to life.

Relifeing Procedure:

A set of tests performed in order to verify that the initial quality and reliability levels have not been affected by time.

Relifing is not usually systematically applied to shelf life components when they reach expiry date. It is initiated whenever an intended supply arises from a batch in question at a post expiry date.


Relifing cont
RELIFING (Cont.) REQUIREMENTS

  • The shelf life and the time that a EEE component can be used after relifing is detailed in a number of ‘Relifing Rules’ published by a number of organisations in the space industry such as:

  • ESA – PSS 01 60

  • Astrium – CDSP-FD012-PRE

  • CNES – QFT-IN-0110MM-5210-02

  • None of these documents are backed up their figures and rules with consistent approach and physics.

  • Astrium under contract from CNES and ESA have updated the ESA rules taking into account field-return and failure mechanism analysis and have established a new storage and de-storage procedure that is to be included in ECSS format.


Relifing cont1
RELIFING (Cont.) REQUIREMENTS

  • The number of samples required for relifing is usually defined in the specification and in is usually 100% or by AQL sample according to test and component type.

  • Specifications and methods used during relifing should be the same as those implemented at the initial procurement, except the most recent update issues should be applied.

  • Required test vary from between specifications and component type but typically they might be:

  • Electrical Parameters

  • External Visual Inspection

  • Solderability

  • Hermeticity



Astrium study i
ASTRIUM STUDY I REQUIREMENTS

  • The CNES study consisted of two elements:

  • Analysing >4000 batches of relifing data from Astrium.

  • 96% of the lots exhibited no problems.

  • Vast majority of failures were visual discrepancies such as corrosion on leads.

  • No defects resulted from a clear failure mechanism induced by storage.

  • A small percentage of defects remained due to random defects implying that it is still necessary to screen at the relife of parts.


Astrium study ii
ASTRIUM STUDY II REQUIREMENTS

  • Batches of stored devices were subjected to life 3000hr life test in order to understand some potential effects of long term storage (10 years) on reliability.

  • Part types tested:

  • Resistors: Metal Film and Power Wire-wound

  • Capacitors: Ceramic and Solid Tantalum

  • Transistors: Signal and Power Bipolar

  • Diodes: Zener

  • IC: IREG and OP AMP

  • Relays: Non-Latching

  • Inductors

  • None of these parts exhibited any clear reliability concern.


Results of the astrium study
RESULTS OF THE ASTRIUM STUDY REQUIREMENTS

  • Astrium findings are summarised as follows:

  • 1) No reliability issue is to be feared on relifed parts when proper storage conditions are in place.

  • No clear effect of storage duration was found on a relifed test yield.

  • 2) Recommendation to allow a longer period of time before it becomes necessary to relife. This period of time is a function of the device type and storage class.

  • 3) Relifeing tests are considered necessary to sort out the low percentage of potentially weak parts.


Astrium conclusion
ASTRIUM CONCLUSION REQUIREMENTS

  • An extended period of storage is now allowed. This will give users a better economical output keeping all reliability guarantees for these parts.


New specification
NEW SPECIFICATION REQUIREMENTS

  • Two classes of storage defined: Class A and Class B

  • Class B: Based on a controlled atmosphere

  • Class A: Based on neutral ambience or dry air



New specification time parameters definition and values
NEW SPECIFICATION:TIME PARAMETERS-DEFINITION AND VALUES REQUIREMENTS

  • T0: Original date code

  • T1: Maximum allowed period with no relifing control

  • ΔT: Maximum allowed storage period after relifing control

  • N: Maximum number of relifing authorised

  • T2: Absolute maximum storage duration

  • N=1 N=2 N=…

  • T0→→→→T1→→ΔT→→ ΔT…→

  • T0→→→→→→→→→→→→→→T2

  • Not all relife steps are necessary.

  • A user can decide to only relife his parts just before they are used i.e. before T2 is elapsed.


Time parameters vs categories
TIME PARAMETERS vs. CATEGORIES. REQUIREMENTS

  • CAT1: Generally for class A storage

  • CAT2: Generally for class B storage

  • CAT3: Case by Case




Electrostatic discharge esd
ELECTROSTATIC DISCHARGE (ESD) REQUIREMENTS

  • ESD is a major cause of premature failure in electronic components

  • Together with Electrical Overstress (EOS) it can account for over 50% of all field failures

  • ESD is totally preventable if proper precautions are taken


What is esd
WHAT IS ESD ? REQUIREMENTS

  • Charge is stored in insulators and is dissipated upon contact with a conductor.

  • Static charge build up in a typical working environment can generate potentials ranging from 100V to 20 kV build up . If this is then discharged through a semiconductor the burst of charge can cause serious damage and cause the device to fail.

  • Components can be damaged by contact with a charged body of by exposure to a high electric field



Esd protective measures
ESD PROTECTIVE MEASURES REQUIREMENTS

  • Handling and storage at RH between 45% and 55%

  • Grounding of devices, equipment and tools

  • Avoid of insulating materials that are subject to charge accumulation (particularly plastics)

  • Conducting work surfaces, floors and storage cabinets

  • Use of containers and packing materials with ESD protection

  • Grounding of personnel by wrist and/or heal straps

  • Nylon coats must not be worn. Untreated cotton is preferred.




The effects of esd
THE EFFECTS OF ESD REQUIREMENTS



Failure analysis
FAILURE ANALYSIS REQUIREMENTS

  • Background research

  • Avoid additional stresses when removing the component

  • Observe proper handling

  • Never de-lid a component until all external tests are completed.

  • De-lid with extreme care and with the most appropriate method.

  • Do not jump to conclusions

  • Report findings as soon as the analysis is complete

  • Give serious consideration to the conclusions and recommendations








Conclusion1
CONCLUSION REQUIREMENTS

  • The internal close-up inspection of the failing devices showed that the metallisation near the termination has become thin to the point of electrical open circuit. The most likely cause of this would appear to be Electrical Over Stress.

  • The point of break down occurs in the weakest area of the network of tracks, which is where current density would be at a maximum during operating conditions.

  • A similar inspection of the good parts shows no visible signs of defect in this (or any other) area.


Intermetallics
INTERMETALLICS REQUIREMENTS



Warning
WARNING! REQUIREMENTS

  • Due to legislative pressures in recent years, the electronics industry is being pushed into eliminating lead from their products and manufacturing processes. This has resulted in many manufacturers moving towards pure tin electroplates.

  • But…

  • PURE TIN ELECTROPLATES CAN CAUSE POTENTIALLY DAMAGING GROWTHS KNOWN AS TIN WHISKERS.


What are tin whiskers
WHAT ARE TIN WHISKERS? REQUIREMENTS

  • ‘Hair-like’ single crystal structures that may grow from tin finished surfaces.

  • Length: Up to 10mm (typically <1mm)

  • Diameter: from 6nm to 10μm (typically ~ 1μm)

  • Growth from the base not the tip

  • Whisker extrusion is driven by mechanical stress relief and diffusion processes in the tin finish.




Tin whiskers
TIN WHISKERS REQUIREMENTS


A possible mechanism for whisker growth
A POSSIBLE MECHANISM FOR WHISKER GROWTH REQUIREMENTS

  • 1. Substrate elements (Cu, Zn, etc.) diffuse into tin along grain boundaries

  • 2. Intermetallic compounds (IMC) may form preferentially in the grain boundaries

  • 3. As a result stress builds up in the tin layer.

  • 4. To relieve stress, whiskers extrude through ruptures in the tin oxide.


Why should you be concerned about whiskers
WHY SHOULD YOU BE CONCERNED ABOUT WHISKERS? REQUIREMENTS

  • Electrical Short Circuits

  • - Permanent (if current < 10s of mA)

  • - Intermittent (if current > 10s of mA)

  • Metal Vapour Arc in Vacuum

  • - Atmospheric pressure < ~150 torr, V> ~18V and I>10s of Amps, then whisker can vapourize into highly conductive plasma of tin ions.

  • - Plasma can form arcs capable of carrying HUNDREDS OF AMPS

  • - Arc is sustained by tin evaporated from the surrounding area

  • Debris/Contamination

  • - Interfere with sensitive optics

  • - Cause shorts in areas remote from whisker origins


What can be done
WHAT CAN BE DONE? REQUIREMENTS

  • Reduction of Stress

  • Hot oil reflow / hot solder dip (preferably Sn/Pb solder)

  • High temperature anneal substrate and tin finish

  • Underplate with diffusion resistant barrier may delay onset.

  • Use of Physical Barriers to Insulate against Potential Shorts

  • Conformal coat or other insulating barriers

  • Increased spacing of surfaces of opposite polarity > 0.5 inches

  • AVOID PURE TIN IF POSSIBLE


Some limitations hot solder dip
SOME LIMITATIONS – HOT SOLDER DIP REQUIREMENTS

  • Hot Solder Dip does not always allow complete coverage of terminals to the component body.

  • There is a risk of heat damage to the component package and the seals.


Some limitations conformal coating
SOME LIMITATIONS - CONFORMAL COATING REQUIREMENTS

  • Conformal coating reduces (but does not eliminate) rate of whisker growth compared to an uncoated specimen.

  • Whiskers have grown through 0.25 mil (6μm) Uralane 5750 coating.


For further information
For Further Information… REQUIREMENTS

  • NASA’s Goddard Space Flight Centre runs the

  • ‘Tin Whisker Home Page’:

  • http://nepp.nasa.gov/whisker/


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