Fine Line Etching Revisited - Part A

摘要

Previous Tech Talk articles looked at the limitation of forming fine line circuits due to undesirable lateral etching (undercut), not just in the print and etch process but also in pattern plating, panel plate/tent and etch, and even in semi-additive processing. It appears that neither photoresist resolution nor plating capabilities but rather etching presents the ultimate limit for these traditional circuitizing techniques. This column looks at ways to extend the subtractive technology to achieve finer features. Some technical advances described here have found commercial acceptance whereas others don't appear to have gained traction. There are several problem areas associated with etching, some interrelated, some independent (see Figure 1). Benefits from process remedies may be seen in one or more of these problem areas. The first problem area, shown in Figure 1, is addressed here in Part A, and the latter three will be dealt with in Part B.