TIN ALLOY ELECTROPLATING SOLUTION FOR SOLDER BUMPS INCLUDING PERFLUOROALKYL SURFACTANT

摘要

Disclosed is a tin-based electroplating solution for forming solder bumps of a flip chip package. The tin-based electroplating solution includes tin methanesulfonate, silver methanesulfonate, methanesulfonic acid, a fluorinated surfactant, an aromatic polyoxyalkylene ether, and water. Also disclosed is a method for forming solder bumps by using the electroplating solution. The method includes (1) electroplating a silicon wafer having a protective layer through which an electrode pad is exposed and an under bump metallurgy (UBM) layer with a copper or copper/nickel plating solution to form copper or copper/nickel pillars on the under bump metallurgy layer and (2) electroplating the pillars with the tin-based electroplating solution to form solder bumps.

主权项

1. A tin-based electroplating solution, comprising:
tin methanesulfonate in such an amount that the tin content of the plating solution is from 40 to 105 g/L; silver methanesulfonate, as an optional component, in such an amount that the silver content of the plating solution is from 0.40 to 3.0 g/L; 70 to 210 g/L of methanesulfonic acid; 0.01 to 100 mg/L of a fluorinated surfactant; 0.5 to 60 g/L of an aromatic polyoxyalkylene ether; and water.