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CMS Module Testing Issues

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  1. CMS Module Testing Issues Perspective from a large scale production project Anthony Affolder (for the UCSB module testing group) CMS Module Testing Issues-Anthony Affolder

  2. Talk Overview • Review current CMS testing procedures • Assorted observations from limited testing experience on CMS components • Outline UCSB module testing program • Personnel, equipment, and infrastructure CMS Module Testing Issues-Anthony Affolder

  3. CMS Testing Overview • Review current CMS testing procedures • Ensure understanding of testing prior to arrival at FNAL/UCSB • Reproduction of hybrid tests on arrival • Make sure any systematic failures in production techniques/materials found as early as possible • M800 pre-production first chance to produce large quantities (>20) of single type of modules • Need to be able to track time development of faults • Answer open questions before full scale production • Need of burn-in of hybrid/optical systems components • Finalization of production procedure • Finalization of testing procedure • Both fault finding and module qualification CMS Module Testing Issues-Anthony Affolder

  4. APV Chip Testing (1 minute) Voltage stressing (6 sec) Basic Functionality Pedestal Calibration Injection (2 MIP) Pipeline FHIT-Industrial Testing (1 minute) Connectivity Basic Functionality Pedestal Calibration Injection (2 MIP) Noise Strasbourg ????? CERN-Pitch adaptor bonding (20 minutes) Basic functionality Pedestal Noise Calibration Injection (2 MIP) Capacitive pulsing pitch adaptor Thermal cycle to –20 C Repeat test Warm to room temperature Repeat test Tests Prior to Arrival at FNAL/UCSB CMS Module Testing Issues-Anthony Affolder

  5. Testing Concerns • Hybrids tested only ~1-20 minutes • Concern about infant mortality problems • Hybrids not completely characterized • Calibration circuit only tested at one injection point • Pipeline pedestal/noise not thoroughly measured • Requirements not consistent between sites • Pedestal cuts changes between test stands • On-chip common mode subtraction “feature” makes noise characteristics of open/saturated channels unpredictable • We are attending CMS tracking week to address issues • Motivate requirements on fault finding/performance issues • Continuation of bringing CDF/D0 production experience to CMS CMS Module Testing Issues-Anthony Affolder

  6. Test System Grounding Issues • PC, DAQ/ARC, LV supplies, and HV supply share common ground • Leads to less than predictable results • Suggest that a common-mode noise standard made • With on-chip common mode subtraction removed (inverter off) • Allows for more uniform testing results CMS Module Testing Issues-Anthony Affolder

  7. Lower Noise Requirements • Improving grounding until common mode noise less than ~0.5 ADC in peak mode/ inverter off allows the use of raw noise as a powerful tool for finding opens, including the location • Sensor-Sensor • Pitch Adaptor-Sensor • APV-Pitch Adaptor (???) • Seen by Charge Injection TOB Module 83 Sensor-Sensor Open Visible CMS Module Testing Issues-Anthony Affolder

  8. Upper Noise Requirements • High noise only affects signal efficiency (clustering) • Use physics (radioactive sources/collision data) to determine cut value • Expect values to be different for different systems SVX CMS Module Testing Issues-Anthony Affolder

  9. Multi-point gain measurements have many advantages More stable More uniformity between chips Tighter Cuts Shows non-linearities Shows non-uniformities within chip Gain Measurement TOB Module 83 Gain Scan (0.5-3.0 MIP) (2 MIP injected)/2 TOB Hybrid CMS Module Testing Issues-Anthony Affolder

  10. Noise Chip Edge Wings Increase in noise at chip edges • But only in a few pipeline cells • pipeline scan=latency scan Deadtimeless effect!! • Fairly easy to reduce/avoid CMS Module Testing Issues-Anthony Affolder

  11. UCSB Short-term Testing Plan • Characterize hybrid (+PA) on arrival • Basic functionality, gain scan, and deep test (ARC) • Re-characterize module on completion of construction • Basic functionality, gain scan, deep test, and IV curves (ARC) • Vienna cold box test fraction of modules (DAQ) • Acts as ~24 hour module burn-in • Identifies mechanical/bond/electrical weaknesses prior to production of large number of modules • Reduces reworking of rod/retrofitting of modules • Rod assembly/characterization/burn-in (when parts and test setups available) CMS Module Testing Issues-Anthony Affolder

  12. Professors Joe Incandela Claudio Campagnari David Stuart Post-docs Anthony Affolder Patrick Gartung (UC-Riverside) Graduate Students Steve Levy Shawn Stromburg +1-2 starting this summer Electrical Engineering Support Sam Burke ESE Master Student Anuroop Gupta (Database/programming) + Assorted Undergraduates and Techs (during full production) Testing personnel at UCSB CMS Module Testing Issues-Anthony Affolder

  13. Clamshell(UCSB) Plastic stand-offs 2 Locating Pins Kapton Extension Cables(UCSB) Easy connection/disconnection Solid mounting of DAQ equipment 1 ARC Controller + 1 ARC FE LV & HV Power Supplies Dry Air Clamshell Current UCSB Testing Setup CMS Module Testing Issues-Anthony Affolder

  14. High Bay (Ground floor) Rod assembly/burn-in Convenient access to loading dock Clean Room (5th floor Physics) Adjacent to production area Module tests Fault finding and deep tests Module burn-in station Visual inspection table Testing Facilities CMS Module Testing Issues-Anthony Affolder

  15. Safety Protocols • LV • OVP,OCP • HV • Crowbar Protection • Electrostatic Protection • Ground mats on tables and floors • Heel straps • Combo tester at clean room entrance • Touch tester at each station (Artist Rendition) CMS Module Testing Issues-Anthony Affolder

  16. Testing Conclusions • Slight modification of testing program would lead to more uniform and consistent fault finding between different sites/systems • Reduce rework performed on completed rods • Location of opens can be identified by combination of noise and internal calibration measurements • Useful for rod burn-in fault finding • Increase in noise at chip edges likely deadtimeless effect • We are willing to study more thoroughly • We have the manpower and the experience necessary to aid in development of the testing program while performing module quality assurance measurements CMS Module Testing Issues-Anthony Affolder

  17. Backup Slides • EVERYTHING AFTER THIS IS BACKUP SLIDES CMS Module Testing Issues-Anthony Affolder

  18. Possible Rod Burn-in Issues • LED systems may be necessary for discovery of “high current” pinholes and location of opens • In current rod burn-in plan, no LED systems available • Would necessitate new techniques to locate “high current” pinholes and opens • New sensor qualification tests, backplane pulsing, lower common mode noise, etc. • Burn-in at module stage provides important information on this issue • LED tests still available • Until rod components arrive this is not an issue CMS Module Testing Issues-Anthony Affolder

  19. Example of DAQ/ARC Differences CMS Module Testing Issues-Anthony Affolder

  20. On-chip common mode subtraction • Inverters share common point • Current flows between channels • Regular channel noise: • s2sraw2-scm2 • Opens/saturated channel noise: • s2sraw2+scm2 • Depending on scm, open channel have higher/lower noise CMS Module Testing Issues-Anthony Affolder

  21. Deadtimeless Scan (ISL) • Issue two triggers with varying time separation • Pattern of commands should include complete set of commands, measurements, resets, etc. • Measure pedestal and noise at each unit of trigger separation • With ISL, every command, chip change of state, and data readout caused pedestal shifts • Would guess similar effect causing wing • May also be related to PC controller • Removed with DPS at CDF (Time Between Triggers) CMS Module Testing Issues-Anthony Affolder

  22. Calibration Injection Test • Enhance pulse shape information with gain measurement • Measure pulse heights at 6-13 calibration injection setting between 0-3 MIPs using internal calibration and fit • Require gain between Glow and Ghigh • Gain uniformity specification??? • Require c2<c2cut (c2 based on noise measurement and knowledge of calibration circuit) • Finds non-linear charge response and gain non-uniformities within chip • Relatively simple to include in ARC software • Only moderately increases testing time • Calibration is fairly sensitive to environment/grounding CMS Module Testing Issues-Anthony Affolder

  23. Test System Grounding Issues (1) Module Testing Final PS System Sensor Sensor Hybrid Hybrid HV HV ARC FE +HV +HV HVGND 2.5V 1.25V GROUND LOOPS!!! Patch Panel/ Interconnect Bus LV ARC Controller LV -5V GND +1.25V -5V +2.5V GROUND LOOPS!!! AOH PC Optical Cables DOH Command And Data Cable CMS Module Testing Issues-Anthony Affolder

  24. CDF Module Burn-in Experience • Significant number of pinholes created during burn-in (even after 5 hours running) • L1- 0.166% of strips • L3- 0.052% of strips • L4- 0.033% of strips • ISL-0.0071% of strips • 7 additional pinholes created during data-taken • L7 burnt-in at depletion voltage • All others burnt-in with over-voltage • Early module burn-in in CMS will indicate pinhole creation rate and effect on rod rework rate CMS Module Testing Issues-Anthony Affolder

  25. Noise Measurements • Lower noise requirements optimized to detect faults in production • Very loose low noise requirement at hybrid level • Noise only changes from ~0.6~0.4 for completely dead pre-amplifier • 20% requirement will fail good channels • Hybrid at UCSB tests better with shaper current set to zero • Tighter low noise requirements at module/rod level • Can identify open types/location • Sensor-Sensor:~1.2 ADC • PA-Sensor: ~0.7 ADC • Chip-PA:~0.5 ADC • Upper Noise requirement set by effect on signal efficiency • Noise sets channel’s thresholds in clustering • Effect is module type dependent • Larger signal and wide pitch minimizes effect on noise on TOB • Determine by source/cosmic testing CMS Module Testing Issues-Anthony Affolder

  26. Wafer Probing Average Pedestal: 67.1 50 <P < 90 ADC Cut FHIT (Industrial Tester) Average Pedestal:~90 ±20% Cut:~72<P<108 ARC Average Pedestal:~110 ±20% Cut:~88<P<132 DAQ Average Pedestal:~170 ±20% Cut:~146<P<194 Pedestal Tests (Current) Pedestal Requirement vary by as much as 70% • Try to develop common test based on detector performance • Different requirements for different sub-detectors CMS Module Testing Issues-Anthony Affolder

  27. Hybrid Gain Measurement(1) 0-3 MIPs 0.5-3 MIPs • Hybrid Tests on steel plate • Large pickup effects cause large c2 when 0 MIP point included • c2 fairly good when excluding zero • Noise of calibration circuit not yet included CMS Module Testing Issues-Anthony Affolder

  28. LED Pinhole Tests Voltage conversion assumes old resistor values in bias return circuit (22KW,100W) New Leakage Current (mA) Necessary With New Resistor Values Bias Ring Voltage (Torsten Franke) m With new resistor values (2.2KW, 681W): need ~120 mA for regular pinholes need >300 mA for “high current” pinholes May cause damage to sensors!!! CMS Module Testing Issues-Anthony Affolder

  29. Gain Measurements (2) Zero point offset Low gain High gain CMS Module Testing Issues-Anthony Affolder

  30. R(22 kO) LED Pinhole Test • LED pinhole test characteristics will change with bias return line modification • Resistance on hybrid (22kW,100W)(2.2kW,683W) CMS Module Testing Issues-Anthony Affolder

  31. Test model(1) • Add hybrid qualification prior to pitch adaptor bonding • Thorough understanding of hybrids by adding more pipeline and gain measurements • Make requirements/calculation algorithms consistent through testing process • Wafer Probing FHITStrasburg Pitch Adaptor Bonding Module Construction Rod Construction/burn-in • Allows for the reproduction of bad channel lists • Eases tracking of fault creation • Motivate requirements for fault finding and on silicon tracker performance • Noise Occupancy • Signal Efficiency • Signal Resolution CMS Module Testing Issues-Anthony Affolder

  32. Test model(2) • Improve system’s noise in order to use as powerful tool • Identification of location of opens • Modify deep tests • Suggest different bad channel cuts specific to component type tested • Remove all percentage requirements (relative to average) • Replace with fixed requirements • Use cooling box as module burn-in until shown unnecessary • Reduces reworking during rod assembly • Adds important information about necessity of LED tests for the finding of some pinholes and opens locations • Demonstrates if hybrid burn-in necessary CMS Module Testing Issues-Anthony Affolder