Cupric Formate/Poly(vinyl Alcohol) Film for Laser Deposition of Copper Metal
Original Publication Date: 1988-Nov-01
Included in the Prior Art Database: 2005-Feb-15
A novel chemical formulation is described for the laser-induced deposition of copper metal upon a wide variety of substrates. The process is a maskless process for the circuitization of printed wiring boards (PWBs) using direct laser writing of a desired conductive pattern, thus supplanting conventional photolithographic or photoresist techniques. The process results in a simplification of process steps over conventional electroless or electrolytic techniques of copper deposition. The combination of cupric formate and poly (vinyl alcohol) results in an aqueous system which enables laser writing speeds of at least 1 cm/s. The process provides for the deposition of copper lines which have a sheet resistance of 5 x 10-2 ohms/sq. and includes a spraying technique which simultaneously applies and cures the precursor film.