METHOD OF FORMING ELECTRICALLY CONDUCTING LAYER

摘要

METHOD OF FORMING ELECTRICALLY CONDUCTING LAYER A conducting layer such as an additional wiring pattern or an electromagnetic insulation layer is formed on a conducting surface such as of a printed circuit board with an insulating layer being interposed therebetween, by a method which includes the steps of: (a) providing a liquid thermosetting composition containing an epoxy resin, a curing agent, a polymerizable compound having at least two acrylate or methacrylate groups and a photopolymerization initiator; (b) applying the composition to the conducting surface to form a coated layer; (c) irradiating actinic light on the coated layer to polymerize the polymerizable compound and to obtain a solid, thermosetting layer, (d) heating the thermosetting layer to cure the epoxy resin and to form the insulating layer; and (e) forming an electrically conducting layer on the cured resin layer. Steps (b) and (c) are repeated until the solid thermosetting layer has a desired thickness. Step (d) may be performed before or after step (e).