Hi, Jan!

49% HF is very strong, so you can dilute it 1:10 in deionized water, or use
BOE (buffered oxide etch);
in both cases, however, few seconds are sufficient to etch the native oxide
on silicon.

Paolo Tassini

-----Messaggio Originale-----
Da: "Grahmann Jan (external)" 
Oggetto: [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.