Takahiro Hidaka

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.

Development of low CHE, negative-tone, photo-definable polyimide for HDD suspension

A negative-tone photo-definable polyimide with a low CHE has been developed for coating suspension heads in HDD applications. In order to select the low CHE polyimide, the stabilization energy of hydration calculated from the polyimide and water by Gaussian 03 was used as an indicator. A good correlation between the stabilization energy and CHE value of the polyimide was obtained and which resulted in the development of a low CHE, negative-tone, photo-definable polyimide. The developed material has a low CHE of 9 ppm/%RH, a CTE of 17 ppm/°C (matching that of stainless steel) and good lithographic properties.