Hi everyone,

I have done some tests recently by measuring impedance (on traces from the
coupons) before and after soldermask.  I found that there are quite a large
drop in impedance after soldermask: 4 to 6 ohms for single ended and 8 to 10
ohms for differential impedance.  Has anyone experienced this?  Could anyone
offer me an explanation of what happened?  We use the same Taiyo product for
a long while.

Your help is greatly appreciated.

Tuan Le
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