Metal Thermal Materials Types Applications Testing

Transcription

1 Metal Thermal Materials Types Applications Testing R.N. Jarrett, C.K. Merritt, J. P. Ross Indium Corporation MEPTEC 2008

2 Metal TIMs Reflowed NOT Reflowed

3 Physical Types Solder Lead or Lead Free High Temp Compliant and high conductivity Compressible Metals Flat Indium Heat-Spring Aluminum Indium Clad Liquid at Room Temp Phase Change Metals

4 Applications Solder TIM, IC s Power Amplifiers IGBT modules LED s Lasers

5 Applications Solder TIM, IC s Generally Indium or Indium contained Good compliancy Excellent conductivity Able to withstand multiple reflow

6 Applications Power Amplifiers IGBT modules LED s Lasers High Temp Step Soldering Paste, Preforms, Ribbon Engineered for Vacuum or air reflow High volume in tape and reel Chosen alloys like AuSn, SnAg, SAC Research on using indium containing alloys for high CTE stress applications and CTE mismatch applications.

7 Test Methods for TIMs

8 Baseline Material Data Thermal resistance as a function of: Temperature Thickness Pressure Thermal conductivity Viscosity Adhesiveness Chemical reactivity Other physical properties 8

9 Thermal Resistance Test Methods Steady State ASTM D5470 conduction profile Thermal test vehicles Electronic device instrumentation Transient Laser flash method Electrical analog method 9

10 ASTM D5470 Test Configuration RTD Probes Heat Source TIM Heat sink (Th-Tc)xA/Q

11 D5470 Test Stand Load Cylinder Heater Block Chill Plate 11

12 TIM properties; Conductivity and compliance Material Indium Thermal Conductivity (W/mK) 86 Flow Stress (psi) 280 or 1.93MPa Copper Lead LMA 20 - Grease 2 -

13 Reflowed vs. Solid vs. SMA

14 Materials Continued Thermal Resistance (cm 2 - o C/W) Thermal Resistance (ASTM D5470) Graphite foil 5 mil 100IN 38 mil 0 Al Foil 4 mil 0 100IN 4 mil D Grease IN-Al-Foil 12 mil 0 100IN 13 mil 0 Power (100IN 13 mil 0) Pressure (psi)

15 Burn-in or insertion data Thermal Resistance During psi Cycling 12 mil 90In-10Ag R-Thermal (cm2 C/W) Time 0 Cycles Cycles Cycles :00 14:00 16:00 18:00 20:00 22:00 0:00 2:00 4:00 6:00 8:00

16 Thermal Test Vehicle 1 cm square die No Back Side Metalization Bare die application 75psi RTD sensors in chip

17 Test Vehicle Configuration Thermocouple Probe Heat sink TIM Substrate Die RTD Sensors 17

18 TTV Temperature Profile TTV Thermal Profile Development (50 Watt Uniform Heating)

19 TTV Thermal Profile Development (50 Watt Uniform Heating) Seconds

20 TTV Thermal Profile Development (50 Watt Uniform Heating) Seconds

21 TTV Thermal Profile Development (50 Watt Uniform Heating) Seconds

22 TTV Thermal Profile Development (50 Watt Uniform Heating) Seconds

23 TTV Thermal Profile Development (50 Watt Uniform Heating) Seconds

24 TTV Thermal Profile Development (50 Watt Uniform Heating) Seconds

25 TTV Thermal Profile Development (50 Watt Uniform Heating) Seconds

26 TTV Thermal Profile Development (50 Watt Uniform Heating) Seconds

27 TTV Thermal Profile Development (50 Watt Uniform Heating) Seconds

28 TTV Thermal Profile Development (50 Watt Uniform Heating) Seconds

29 TTV Thermal Profile Development (50 Watt Uniform Heating) Seconds

30 TTV Thermal Profile Development (50 Watt Uniform Heating) Seconds

31 TTV Thermal Profile Development (50 Watt Uniform Heating) Seconds

32 TTV Thermal Profile Development (50 Watt Uniform Heating) Seconds

33 Material Comparison in TTV (As Installed) Time 0 Time 0 33

34 Material Comparison in TTV (After power cycling) Power-On Cycles Power-On Cycles 34

35 Material Comparison in TTV (After 90 C Exposure)

36 Summary Statements Solders may not be considered TIMs, but they are part of the thermal stack up. There are now many forms of metal that can be used to transfer heat, including compressible metals and liquid metals There are various ways to test TIMs such as the ASTM method and using Thermal Test Vehicles to determine if the application is right for a metal TIM. There are still many applications where polymers can be used and are preferred, however in the right applications metal can out perform Polymer Solders, Die attach and compressible applications