| 摘要 |
<p>A process is disclosed for applying a photopolymerizable solder mask layer to a printed circuit substrate containing a plurality of holes which comprises the steps of: a) applying to the substrate surface a photopolymerizable liquid to substantially fill the holes, which is activated by actinic radiation in a first spectral region; b) laminating a preformed photopolymerizable film to the substrate through the applied liquid, which is activated by actinic radiation in a second spectral region, and which transmits actinic radiation in the first spectral region; c) imagewise exposing to actinic radiation which includes radiation of the first and second spectral regions to form photopolymerised areas of the liquid and the film, extending over and within at least a portion of the holes, wherein the exposed liquid in the holes is photopolymerised to a depth of at least 25 % of the hole depth; d) removing unexposed areas of the liquid and the film; e) contacting the printed circuit substrate with molten solder.</p> |
