HOME FAQs BOOKS JOBS: Help Wanted Suggestions you are here: Hotline/Forum => Letter 34022

Plating Aluminum pads on an IC

+++++

I am looking for a solution to mounting solder balls (SnPb or InPb) onto Aluminum pads on a silicon IC. The IC pads are Aluminum. As I understand it, the Aluminum pads will not bond well directly to a solder ball, and thus some form of pad treatment must precede the solder balling procedure.

Mechanically, the IC can be dipped in a bath, as the IC has a passivation layer (glass) over the necessary circuitry, and recesses in this passivation layer where the Al pads exist. The pads are 150um square and about 3um thick.

Would electroless nickel work for this? If so, what is the procedure? Can this be done on-site for low volumes, or does it need to be subcontracted to a shop?

Any other ideas for this problem?

Thank you for any responses.

Steve Chacko
Furaxa, Inc. - Orinda, California, USA

+++++

Your problem could be solved by electroless nickel as you suggest, and then plated with copper and autocatalytic electroless silver.

Best regards,

Karl Lundahl
- Mölndal, Sweden

ANSWER or FOLLOW UP POST an unrelated QUESTION HOT Topics

Disclaimer: It is not possible to diagnose a finishing problem or the hazards of an operation via these pages. All information
presented is for general reference and does not represent a professional opinion nor the policy of an author's employer. The
internet is largely anonymous; some names may be fictitious and some recommendations may be deliberately harmful.

If you are seeking a product or service related to metal finishing, please check these Directories: