Si through-hole interconnections filled with Au-Sn solder by molten metal suction method

Abstract

This paper deals with a fabrication method of conductive through-holes in a silicon substrate, which can be applied for micro electro-mechanical system (MEMS) devices or high-density packaging. The through-holes are formed by deep reactive ion etching (DRIE) and filled with Au-Sn solder by molten metal suction method (MMSM). The MMSM we have proposed is capable of filling high aspect ratio thorough-holes with conductive metal. We could make more than 18,000 conductive through-holes, 30 /spl mu/m in diameter and 300 /spl mu/m in depth, in a 4 inches sized silicon (Si) wafer. We report the principle of the filling, the fabrication processes and the structure of the through-hole interconnections.