Metal wiring method for an undercut

摘要

A metal wiring method for an undercut in a MEMS packaging process includes disposing a MEMS element on a silicon substrate, welding a glass wafer to an upper portion of the silicon substrate having the MEMS element disposed thereon, the glass wafer having a hole formed therein for connecting a metal wiring, depositing a thin metal film for the metal wiring in the hole, and ion-milling the deposited thin metal film. By the ion-milling, the method is capable of connecting a metal wiring to a via hole having an undercut.