Shigeru Nobe

Development of low temperature curable positive tone photosensitive dielectric material

Recently, low temperature curable photosensitive dielectric materials are attracting much attention in semiconductor package application to avoid thermal damages of the semiconductor devices. AH-1000 is a low temperature curable positive tone photo- definable material. In this paper, we report the mechanical, thermal, and adhesion property of AH-1000 together with its chemical resistance. A wafer level package (WLP) using AH-1000 as redistribution layers indicates that AH-1000 has enough mechanical toughness. It also suggests that higher elongation and lower Youngs modulus are effective to eliminate mechanical stress to solder balls for dielectrics.

Nano size cerium hydroxide slurry for scratch-free CMP process

We report recent progress in a novel cerium hydroxide polishing slurry with particle size of about 5 nm nano size cerium hydroxide (NSC) abrasive. NSC has succeeded in omitting particles over 1 μm, and in reducing scratches to 1/30 of those with calcined ceria slurry. Even though, NSC maintains oxide removal rate similar to conventional ceria. Mixing NSC with the specific additives brought out tunable polishing of SiO2, SiN, and poly-Si.