Novel Metal Based Thermal Interface Materials for Flip Chip Ball Grid Array Packages

Flip chip ball grid array (FC-BGA) packages are preferred in high-performance computing and advanced packages because of their superior signal integrity, high input/output density, good thermal performance and small footprint. Due to a high thermal design power (TDP), these packages demand effective thermal interface materials (TIM) for heat dissipation. Added challenges are inherited due to multiple reflows after the integrated heat spreader attach, namely in the ball attach reflow and surface mount reflow steps. This paper will discuss the challenges posed by large die area packages for polymer TIM (PTIM) technology. After this, two novel metal-based TIM technologies developed and tested for FC-BGA packages will be addressed. Finally, the paper will highlight some of the advantages and disadvantages between these TIM technologies in terms of key upstream and downstream process impacts. The data shows that metallic-based TIM materials allow for peak product performance under the strict requirements of a networking and server environments, whereas PTIM is hard-pressed to meet the strict use conditions set with every passing generation.