A Burn-In-Test Based on a Modified JEDEC Thermal Cycling Standard for Carbon Nanotube Based Thermal Interface Material

Three (3) thermal interface materials (TIMs) consisting of carbon nanotubes (CNTs) bonded to silicon or graphene-silicon compared to an indium TIM for amplifier life cycle performance. CNT-graphene sample was chosen with a dense border of tall CNTs and shorter less dense CNTs as the bulk device. A densely powered printed circuit board assembly (PCBA) consisting of evenly hundredth of a meter spaced amplifiers, passive components, and their associated TIMs are constructed. The fully assembled PCBA completes a life cycle test and examined for condition assessment. The infrared radiation (IR) thermal image identifies the hottest point on the PCBA. A limited lifecycle series of fifty (50) thermal cycles are performed. Preliminary results show that different TIM quality give different results. On the first trial, Indium is the best TIM, but CNTs with graphene show promise as a high performance TIM. On the second trial CNT TIMs outperformed the leading Indium TIM. Post processing of the CNT TIMs are analyzed. After the completion of the life cycle test the CNT based TIMs are examined via various imaging techniques. SEM shows there was a small amount of delamination of the CNTs from the graphene and silicon substrate. The CNT only sample developed dead zones where there were was exposed clean silicon. Thermal cycling and mechanical stress of the devices lead to more counts of reaching the maximum surface temperature.