Toni:

You perhaps do not understand, that in the US, some wedge voids, are
acceptable, and thus if they exist, but do not show, the PCBs are accepted,
and function well, and at the end of the day, this is the important point.

In the US, most people are not using Peroxy Sulfuric etches where you are,
and thus the use of DMAB hides the existance of the wedge void, which makes
the PCB acceptable to the customer.

You are right, that it is possible, althought there is much argument about
whether it  is true, that the use of DMAB may make the PCB less robust, and
therefore less fit for use.  What you have to understand is that truth and
reality have never had a real strong position in our industry, and appearance
is almost everything.  Since DMAB makes the finished PCB appear more robust,
its use is almost univeral in the US.  The reality may be completely
different, but so far, given the incredible number of PCBs in service that
have been treated with DMAB, it is unlikely that there will be a change in
the industry in the near future.

What you have to realize further, that your use of Peroxy Sulfuric etch, at
the stage that you use it, makes your process is unique, and since DMAB
cannot protect against attack by peroxy sulfuric, the DMAB may not even be
able to offer you even cosmetic protection.

Hope this helps your understanding.

Best

Rudy Sedlak
RD Chemical Company
Mountain View CA
415-962-8004
Fax 415-962-0370