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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.
More Columns from Trouble in Your Tank
Trouble in Your Tank: Interconnect Defect—The Three Degrees of SeparationTrouble in Your Tank: Things You Can Do for Better Wet Process Control
Trouble in Your Tank: Processes to Support IC Substrates and Advanced Packaging, Part 5
Trouble in Your Tank: Materials for PWB Fabrication—Drillability and Metallization
Trouble in Your Tank: Supporting IC Substrates and Advanced Packaging, Part 5
Trouble in Your Tank: Electrodeposition of Copper, Part 6
Trouble in Your Tank: Electrolytic Copper Plating, Part 5
Trouble in Your Tank: Processes to Support IC Substrates and Advanced Packaging, Part 4