Hi Chris,

Preparing the aluminum for E-less nickel - Clean, etch, de-ox and zincate
removes a significant amount of aluminum.

If you are using an alkaline zincate, this is definitely your problem.

I recommend minimizing pre-etch and definitely use an acid zincate process.

Regards,
Dave

David Roberts (Wafer Plating Specialist)
Prodigy Surface Tech (408) 469-3203 cell
807 Aldo Ave., Suite 103
Santa Clara, CA 95054
Phone (408) 492-9390
FAX (408) 492-9391

-----Original Message-----
From: Christian Engel [mailto:engel.christian@gmx.de]
Sent: Tuesday, March 15, 2011 12:27 PM
To: mems-talk@memsnet.org
Subject: [mems-talk] Electric problem after electroless plating

Hello @all,

currently I am working on a planar coil fabricated on a glass substrate. The
structure starts with an Al-layer, 1µm thickness. Since its resistance is
much too high because of the poor aspect ratio, I want to use electroless
plating for decreasing it. For this I used an UBM-process , consisting of
Zn, Ni and finally Au. Final thickness is about 5µm. But I wonder about the
resistance which gets doubled after electroless plating. Any suggestions
what could have gone wrong?

Best regards, Chris