Over 150 deg, the Cr and Au interdiffuse and can't be etched away by KI I2.
Aqua Regia does it reluctantly.
Shay

-----Original Message-----
From: [email protected] [mailto:[email protected]]
On Behalf Of Zhang Peng
Sent: Thursday, December 01, 2005 5:03 AM
To: [email protected]
Subject: [mems-talk] Gold etching

Dear all,

I met a problem on gold etching.
A 1500A Cr + 500A Au layer was sputtered and then annealed at 400C for 5min.
The IK+I2+H2O=40g:5g:400ml solution was used to etch Gold. But the Gold can
not be etched away. The solution with more I2 was also tried, but still the
same result. Could the annealing process cause the diffusion of the Gold
into the Chrome and cause this etching problem? Should you have any
experience or ideas on dealing with this problem, pls give me suggestions.
Thanks a lot!