| 摘要 |
High density primary wiring patterns are formed on printed wiring boards with far less than 0.005 inch spacings and wiring conductor widths, which surprisingly permit wider conductors of at least three times the wiring spacing thus less likely to have open circuit or substrate adherance defects. This is achieved by depositing on an irregular surface of a conventional "flat" panel insulator a thick liquid photopolymer layer of paste-like consistency, such as 0.006 inch thickness, flattening it with the image bearing side of a glass plate phototransparency to produce high resolution wiring patterns comprising ridge tops defining insulating spacing between channel conductor areas therebetween by means of uncollimated actinic radiation, forming thin conductive layers 0.0014 inch thick on the channel bottoms and sidewalls to produce wider conductors, and sanding off the flat ridge tops to assure that there are no short circuits between adjacent conductors.
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