| abstract |
A method for selectively metallizing one or more through-holes, other openings (such as slots), or edges of an electronic circuit package comprising the steps of forming a layer of seeding solution on a drilled surface of a substrate of interest exposing this layer to light of appropriate wavelength, through a mask that does not completely cover the through-holes or openings and thereby results in the formation of metal seed on regions of the substrate surface corresponding to the regions of the layer of seeding solution exposed to light; removing the unexposed regions of the layer of seeding solution by subjecting the exposed and unexposed regions of the layer of seeding solution to an alkaline solution. Thereafter, additional metal is deposited, e.g., plated, onto the metal seed using conventional techniques. Significantly, this method does not involve the use of a photoresist, or of a corresponding chemical developer or photoresist stripper. Of additional significance, this method yields plated through-holes or other openings, each of which can accommodate multiple wires, rather then the traditional one wire per through-hole. |