Electronic package method and structure with cure-melt hierarchy

Abstract

Disclosed herein are embodiments of electronic package incorporating a thermal interface material (e.g., a metal TIM) that is positioned between a lid and a chip on a substrate. The TIM has a predetermined (i.e., repeatable) minimum thickness and is further registered to the top surface of the chip (i.e., the TIM has an essentially symmetric shape and does not extend vertically along the sidewalls of the chip). Also, disclosed herein are embodiments of a method of forming such an electronic package that uses a hierarchical heating process that cures a lid sealant, thereby securing the lid to the substrate, and then reflows (i.e., melts and cools) the TIM, thereby adhering the TIM to both the chip and lid. This hierarchical heating process ensures that the TIM has the above-mentioned characteristics (i.e., a predetermined minimum thickness and registration to the top surface of the chip) and further provides robust process windows for high-yield, low-cost electronic package manufacturing.