Mold Compound Adhesion Reliability with SiN and SiON Passivation

摘要

Delamination of mold compounds under thermal stress conditions such as Air-to-Air Temperature Cycling (AATC)(～55°C ～125°C) was studied for two passivation surfaces; SiN and SiON using C-Mode Scanning AcousticMicroscope (CSAM) and electrical testing for different intervals up to 2000 cycles. Both passivation surfaces weretreated with oxygen-argon plasma prior to the molding process. It is found that SiN surface performed better thanSiON electrically and without showing any delamination for the mold compound studied. Both passivation surfaceswere analyzed for various surface groups by TOF-SIMS analysis immediately before and after the pre-mold plasmatreatment process. Different surface groups such as CH, NH etc. were identified, but the major difference was foundin the OH intensity. Fraction of OH is significantly increased after plasma treatment for SiN surface while it isdecreased for SiON surface. It is inferred that OH group can play a role in enhancing the mold compoundpassivationadhesion and hence provide better delamiantion resistance.