Cr has a problem of developing oxide layer and its one of the main cause of
poor adhesion. I encountered this problem about couple of year back when I was
using Cr with Au. Oxide layer on Cr creates bad adhesion and my Au layer used to
peeled off. Try to deposit both metals in one vacuum environment to avoid this
problem of bad adhesion.

Kind Regards
Dr Hamood Ur Rahman,
College of Electrical and Mechanical Engineering
National University of Sciences and Technology (NUST)
Islamabad, Pakistan


________________________________
From: Xiaohui Lin 
To: General MEMS discussion 
Sent: Mon, May 23, 2011 5:19:51 AM
Subject: [mems-talk] Electroplating Ni on Cr thin film

I am trying to electroplate Ni (1um thick) bars on Cr thin film (50nm) which
serves as a seed layer.

But after electroplating, I found the adhesion is very weak. Using tweezers
can easily scratch the Ni bar off the Cr surface without any damage to the
Cr surface, which indicates very weak adhesion.

I know that Cr may oxidized in air. Does the oxidation count for the weak
adhesion?

Did anyone has similar experiences? I am crazy now:P

Thanks ahead.