・ The UBM layer etching process of copper used in wafer-level packaging, and has a high selection ratio for other metals and substrates, such as: Au, Sn, SnAg, Ni, Al, Polyimide, Glass, SiO2. ・ After the etching, the side etching amount and undercut of the electroplated copper circuit are small, which is suitable for the fine pitch process. ・ Stable etch rate and long bath life.
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