JEDEC standards for the semiconductor industry include practical test methods for accelerated life testing of indium thermal interface materials
Accelerated life testing is a necessary part of material evaluation to understand the reliability of a material before implementation in a product.
In previous posts, I have discussed the impact of accelerated life testing on low melt alloys. For the lowest temperature metal or indium thermal interface materials, the procedure may need to be altered to prevent melting of the alloy during accelerated life testing such as temperature cycling. For most alloys, standard procedures can be followed.
Standard accelerated life tests for indium thermal interface materials (and most other thermal interface materials as well) rely on the basic Arrhenius principles to determine acceleration factors for failure rate calculations and equivalent stress testing protocols. The Arrhenius equation demonstrates an empirical relationship between the rate of various reactions that occur with the TIM as factors such as temperature change.
R = A exp (-EJkT)
where
R = rate of the process
A = a proportional multiplier
E. = activation energy
k = Boltzmann's constant, 8.617 343(15)×10−5 eV·K-1
T = Absolute temperature in Kelvin
While this equation provides the theory behind many iterations of accelerated life testing, the JEDEC test standards provide practical accelerated life test procedures for thermal interface materials and are appropriate for use in testing indium thermal interface materials.