We manufacture W/Cu & Mo/Cu materials for the electronics packaging market. These materials are typically plated with Soft gold over nickel for solderability. One of our customers is attaching die to our substrate using a 0.001" thick 80/20 Au/Sn preform. The gold plating on our sub-mount is 100 micro-inches thick. The Au/Sn is leaving excessive voids after reflow. Any ideas of what may be causing the poor solderability? Is the gold plating too thick?
Bob Cronk Spectra-Mat, Inc. - Watsonville, CA , USA ^
Is your customer using a plasma preclean process shortly before soldering? This could be important. Ask them to do a surface tension or wetting-angle test.
Mandar Sunthankar - Fort Collins, Colorado ^
finishing.com is made possible by ... this text gets replaced with bannerText
Disclaimer: It's not possible to fully 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 & unvetted; some names may be fictitious and some recommendations might be harmful.
If you are seeking a product or service related to metal finishing, please check these Directories: