Metal adsorbent for alkaline etching aqua solutions of Si wafer

Tamada, Masao; Ueki, Yuji; Seko, Noriaki; Takeda, Toshihide*; Kawano, Shinichi*

Radiation Physics and Chemistry, 81(8), p.971 - 974, 2012/08

https://doi.org/10.1016/j.radphyschem.2011.10.008

In the fabrication process of semiconductor, Si wafer surface is etched by strong-alkaline aqua solutions such as 48 % NaOH and KOH. If the etchant is contaminated by Ni and Cu, smalls pits which appeared on Si surface in the process of surface polishing caused poor production yield of the Si wafers. Available commodity adsorbent resins shrink in the high concentration of alkaline aqua solutions and bias flow occurred in the case of their column packing. Hence, novel fibrous adsorbent was synthesized by radiation-induce graft polymerization on nonwoven materials composed of pure polyethylene fibers. The obtained fibrous adsorbent module (TM: Metolate) had practical cost and performance that flow rate is ten times and effective capacity is some tens times higher than commercialized adsorbent resins and fibers.

Preparation of metal adsorbent from poly(methyl acrylate)-grafted-cassava starch via irradiation

Suwanmala, P.*; Hemvichian, K.*; Hoshina, Hiroyuki; Srinuttrakul, W.*; Seko, Noriaki

Radiation Physics and Chemistry, 81(8), p.982 - 985, 2012/08

https://doi.org/10.1016/j.radphyschem.2011.10.011