New and Unique CMP Material Solution for the Enablement of High Removal Rate Polymer CMP and other Advanced Packaging Applications

Abstract

Polymer materials like epoxy mold compounds (EMC), polyimides (PI) are used in the advanced packaging applications. Chemical mechanical planarization (CMP) is a process useful in removing undesired surface topography and surface defects and in forming features on a substrate by removing excess deposited material. However, removal rates (RR) of polymers are too low by conventional CMP to be useful in advanced packaging technology. A novel slurry system has been developed. A two-step sequence combining both high-speed mechanical abrasion with novel slurries for coarse polishing and conventional polymer CMP technology for final fine polishing has been evaluated. A removal rate of more than $10\ \mu \mathrm{m}/\min$ has been observed for EMC which is roughly one order of magnitude higher than that obtained with conventional CMP process. A final fine polish step with a regular CMP slurry has almost restored the initial roughness in case of PI. The novel slurry has shown high RR for multiple substrates and has shown about 7:1 selectivity for PI removal against copper. This solution can bring grinding and CMP under one platform with more process control compared to grinding alone.