摘要 |
<p>Process for preparing multilayer printed circuits comprising laminating simultaneously or sequentially to a substrate bearing a circuit pattern two photopolymerizable layers, the lower layer formulated for bulk response as defined and the upper layer formulated for surface response as defined; exposing the laminate to actinic radiation through a circuit image related to the circuit pattern on the substrate; embedding finely divided metal, e.g., copper, to the tacky image areas; exposing the toned laminate to actinic radiation through an image of at least one overlying segment of the conductive circuit pattern; removing unexposed photopolymer from the two layers to form vias; embedding finely divided metal, e.g., copper, or catalyst to the side walls of the vias; optionally, curing the image by exposing to actinic radiation and/or by heating; plating to form an interconnected electrically conductive circuit. Additional circuit layers can be added by repeating the process using the newly plated circuit pattern as a substrate.</p> |