Photochemical Image Formation Process for High Density PrintedCircuit Patterns

摘要

A new method for fabricating high density printed circuit boards has been investigated. The procedure used forphotoselective metal deposition on the substrate consists of five steps: adhesion treatment, sensitization, nucleation,fog inhibition and electroless metal deposition. An adhesive coated substrate was sensitized by introducing an aqueoussolution containig anthraquinone sulfonic acid sodium salts, reducible noble metal salts and alcohol. The sensitizedsubstrate was then exposed through a mask to a u.v. light. The noble metal nuclei produced by exposure weredeveloped by electroless copper deposition after rinsing with aqueous solutions containing complex agents.Electrically-conductive patterns thus obtained can be further intensified by second electroless plate making.