"AlSiC-Based Hybrid Composite Tool Kit"

1. "AlSiC-Based Hybrid Composite Tool Kit" By Richard W. Adams and Mark A. Occhionero Ceramics Process Systems 111 South Worcester St Chartley MA 02712-0338 www.alsic.com New England IMAPS 31 Annual Symposium Thursday May 6, 2004

2. "AlSiC-Based Hybrid Composite Tool Kit" • Abstract: AlSiC and multi-component structures provide unique thermal management electronic packaging solutions for microwave, microelectronics, power electronics, and optoelectronics that result in improved product reliability. This paper reviews volume AlSiC manufacturing applications today, and then describes examples of a wide range of possibilities for multi-component, multi-functional thermal management structures.

3. AlSiC Packaging for Electronics Thermal Management- Basic Parameters • Controlled Thermal Expansion • Engineered CTE values - for component and assembly compatibility = reliability • Engineered solutions can create typical CTE values 7-12 ppm/°C • Thermal Dissipation • High isotropic thermal conductivity, typical = 200 W/mK • Lightweight • 3 g/cm3 • Cost Effective Manufacturing Capability - net shape cast

4. SiC preform injection molded AlSiC product infiltration casting CPS AlSiC Fabrication - Defines Properties and Design • SiC to Al-metal ratio defines thermal expansion • 1st - SiC preform with controlled and variable volume content • 2nd - Infiltrate with Al-metal to form the AlSiC composite • Thermal conductivity determined by components • Electronic Grade SiC 230 - 260 W/mK • A356.2 Casting Alloy 160 W/mK • Little influence of ratio of 2 components • net shape forming • preform is ~ smaller than final part • infiltration tool = final dimensions • eliminates costly machining

5. ~37 vol% SiC ~55 vol% SiC SiC ~63 vol% SiC SiC particles uniformly distributed in continuous Al-matrix See www.alsic.com AlSiC - Metal Matrix Composite Material

6. AlSiC Tools • Marry Properties to Product Design • Design Functionality • Basic AlSiC • lids • baseplates • package system structures • AlSiC + Concurrent IntegrationTM • Cooling Tubes - active fluid • HOPG / Diamond - passive transfer • Dielectric Ceramic Inserts - Ω isolation

7. Basic AlSiC Design See www.alsic.com • Pick compatible AlSiC CTE • Seal rings • Substrates • Devices • Design rules for AlSiC casting • Draft Angles • Thicknesses • Radii • Al-Rich Areas for conventional machining

8. Basic AlSiC - lids • Applications: • Microprocessor Lids • DSP • Flip Chip Lids • Optical Lids • Volumes • 100 pcs - 40K/week • Price (Volume/Complexity) • $ 2 - $ 5 in volumes of ~100K/yr • Simple to Complex Geometries

9. Basic AlSiC - lids • Product is net-shape fabricated - no machining • multiple pedestals • angled features • radial alignment features • septums and walls • lower cost than machined Aluminum alternative • Complex Geometries

10. Basic AlSiC - Baseplates • Compatible CTE = unlimited thermal cycling of package • AlN soldered to AlSiC • Design • Dome Shape - Side 1 • Compressing a dome shape against flat cold plate maximizes heat transfer • Flat - Side 2 • Attachment of “flat” substrates Thomas Schuetze, Herman Berg, Oliver Schilling “The new 6.5kV IGBT module: a reliable device for medium voltage applications”, PCIM September 2001 flat dielectric substrate surface convex bow cooler plate surface

11. Concurrent IntegrationTM -High Density Interconnect (HDI) for GaAs Microwave Transmit/Receive Packages • Dielectric Feedthrus First, dense dielectric ceramic ferrules are inserted into the QuickCastTM infiltration tooling along with the SiC preform. Then, the Al-metal, that infiltrates the SiC preform to form the AlSiC composite, hermetically bonds and fills the ferrules to form coaxial feedthrus.This process is termed Concurrent IntegrationTM.

12. Concurrent IntegrationTM - AlSiC LED Submount • Product Features: • multiple pedestals • angled features • partially machined to expose Alloy 49 pads for assembly • Alloy 49 bonded direct to Al phase of AlSiC • Alloy Metal Inserts Alloy 49 pad

13. AlSiC HOPG 1300 W/mK AlSiC AlSiC laser diode TEC substrate system showing TEC mount area (top) and the cross section showing the HOPG insert in the AlSiC composite (bottom). Concurrent IntegrationTM - Optoelectronic AlSiC TE Cooler Substrate with HOPG Heat source surface • High Thermal Conductivity Insert • Product Features: • Pyrolytic Graphite (PG) compressively encapsulated within AlSiC • Thermal conductivity 1300 W/mK • PG located near heat source/TE cooler position. • Selective use of costly material 1350 W/mK 1350 W/mK

14. Concurrent IntegrationTM - Liquid Flow Thru Cooling • Cooling Tube or Heat Exchanger Product Features: • Tube intimate within AlSiC casting • SiC overmolded onto tube • Direct bond AlSiC to tube • Maximize heat transfer AlSiC to tube • Low cost one step assembly • CPS Patented process

15. TOP BASE Metallurgical Bonding AlSiC to AlSiC • Friction Stir Welding • Bonding of Engineered Al-Rich Areas within AlSiC casting • Al Solder Bonding Processes • Various commercially available • Desired Al Skin Present on AlSiC Heat sink and housing are joined by Friction Stir Welding.

16. QuickCastTM High Pressure Precision Aluminum Casting • Aluminum-only precision casting • Tolerances in the +/-0.003” Range • Low cost tooling • Rapid product introduction and moderate production rate • Option for Concurrent IntegrationTM • Diamond, PG, etc inserts • High Output LED light housing • RV, Boats, Theater, Safety Lighting

17. Summary "AlSiC-Based Hybrid Composite Tool Kit" • Basic AlSiC Properties coupled with Concurrent IntegrationTM • AlSiC = Engineered CTE, Thermal Conductivity, Lightweight • CPS AlSiC = • Shape Complexity and Tight Tolerance - net shape • Attractive Value Proposition for many (growing number) of Applications • Concurrent IntegrationTM Presents Thermal Package Design Options - limited only to your imagination • AlN, ZTA, Al2O3, Si3N4 Substrates/Ferrules, etc. • Stainless steel, alloy 49, Titanium inserts • Tubes, Heat exchangers, welded pin fin coolers • High Thermal Conductivity Diamond, PG

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