Jan:
Have you tried covering the pads with photoresist to protect the gold? Also
there are some good tapes that can be applied that will hold up to HF etching. I
assume you are etching the backside. Is this true? Also Brewer Science makes a
spin on polymer that holds up to long etches in KOH maybe it would work for you.
Bob Henderson
-----Original Message-----
From: Grahmann Jan (external)
Subject: [mems-talk] Sputtered Cr-Au layer resistance against HF
I have a pad metallization consisting of 100nm Chromium and 300nm Gold. Both are
sputtered right after each other in vacuum. The problem is, that I need to etch
with 49%HF for a few minutes and the Cr-Au layer is practically lifted off the
siliconsubstrate. The Wafers were cleaned befor sputtering but have a native
oxide layer. Does anyone know a possibility to work with Cr-Au or another
metallization which withstands the HF? I need gold on top.