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Trouble in Your Tank: Negative Etchback: Is it Really OK?
Introduction
There are always questions and concerns with respect to the plating integrity at the interconnect of a multilayer circuit board. Several different opinions exist as to what degree of etchback is acceptable. And as the reader will discover later, negative etchback is acceptable to some degree, depending on the class of product for which the circuit board is intended. It is a good idea to understand positive and negative etchback.
Positive vs. Negative Etchback
Fabricators and their customers often debate whether or not the desmear operation prior to metallization should attempt to remove sufficient resin, not only to ensure a clean interconnect, but also to impart the “three-point connection” (Figure 1).Read the full article here.
Editor's Note: This article originally appeared in the April 2013 issue of The PCB Magazine.
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