Hi,

Does anyone have experience from flux free soldering of Sn60/Pb40 on thickfilm. I have tried, but I just can't get the solder to adhere (it peels right off when I'm using a scalpel). I'm using solder preforms and Du Pont's thickfilm paste 4596 (Pt/Pd/Au) in a convection oven with nitrogen atmosphere. I have burnished the thickfilm with an eraser and tried to plasma etch the preforms in argon.

What am I doing wrong? My guess is that there is a thin oxide layer on the preform. Should I use any other method of removing it or should I plasma etch more (I used Ar, 80mTorr, 500W, 13.56 MHz for 5, 10 and 20min).

I'd be very grateful for any tips!

Hakan Tornqvist
Ericsson Microwave Systems

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