Doug Sober's note on this subject (Sat, Dec 16) suggests that single sided
laminate can absorb plasticizers from release films.  The obvious (albeit
more costly) solution is to use a double sided laminate and etch off the
excess copper.  The replicate surface thus produced also makes an excellent
bonding surface for the relam.

While foil lam is a cost-effective way to build a multilayer, which results
in reduction in registration issues and minimizes layer feature distortion,
there may be occasions when a cap construction is desirable due to design
requirements.  In such cases the use of a double clad with one side etched
off, as mentioned above, will be the best way to go.

The issue of matte surface and moisture pickup are valid, but drying details
prior to lamination, especially with some of the higher performance
materials, is already standard practice and it shouldn't be especially
problematic to include the cap layer along with others being baked (i.e.
after oxiding).

I've discussed this with our tech service experts, all of whom made
essentially the same comments.

Chet Guiles
Arlon MED