AlSiC-Based Hybrid Composite Tool Kit

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"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

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"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.

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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

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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

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AlSiC - Metal Matrix Composite Material
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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 - O isolation

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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

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Basic AlSiC - lids

• Simple to Complex Geometries

• Applications
• Microprocessor Lids
• DSP
• Flip Chip Lids
• Optical Lids
• Volumes
• 100 pcs - 40K/week
• Price (Volume/Complexity)
• 2 - 5 in volumes of 100K/yr

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Basic AlSiC - lids

• Complex Geometries

• Product is net-shape fabricated - no machining
• multiple pedestals
• angled features
• radial alignment features
• septums and walls
• lower cost than machined Aluminum alternative

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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
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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.
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Concurrent IntegrationTM - AlSiC LED Submount

• Alloy Metal Inserts

• 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 49 pad
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Concurrent IntegrationTM - Optoelectronic AlSiC
TE Cooler Substrate with HOPG

• 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

Heat source surface
1350 W/mK
1350 W/mK
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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

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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.
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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

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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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