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Process and Material Adaptations for HDI Requirements【View details】

As mass production of fine line MLC is becoming a reality, etched line uniformity on one ounce copper with 2 mil lines and spaces has been a hotpoint. Etch uniformity can be measured by tedious microscope readings or electrical resistance1. It has also been studied by partially etching a copper foil and measuring thickness distribution before and after etching by an eddy current2. Etch uniformity is visualized three dimensionally with a special AOI machine3. A distinction is made between the control of etch rate, etch uniformity, and etch factor. The distinction between etch rate and et【View details】