Fine Line Etching of Tungsten Using a Thin Film Aluminum Mask
Original Publication Date: 1988-Jul-01
Included in the Prior Art Database: 2005-Feb-15
A method for etching tungsten to produce fine lines is provided and comprises: depositing a tungsten film on an oxidized silicon substrate; depositing a thin aluminum film atop the tungsten film; depositing a photoresist in a desired pattern atop the aluminum film; chlorine-based reactive ion etching the aluminum film to produce a desired aluminum film pattern; and further reactive-ion etching the exposed tungsten film portions to transfer the pattern to the tungsten film. If desired, the aluminum mask may then be removed by another reactive ion etching step. The resulting fine line pattern will show no undercut and negligible etch bias. The provided etching method can be carried out in a single process chamber as both the aluminum and the tungsten are reactive ion etched.