| 摘要 |
In a first process step, a positive photo-etching base material is applied to the surface of a substrate. The photo-etching base material is exposed imagewise, through a mask, to actinic radiation, whereupon a carboxylic acid or other acid, soluble in a solution, forms on the exposed parts. Thereafter, the entire photo-etching base layer is subjected to a treatment with hot steam, which renders the acid formed insoluble in alkaline solvents and relatively insensitive to further radiation exposure. Thereafter, the entire surface of the etching base is exposed to radiation in order to solubilise the parts which were originally not irradiated through the mask. The etching base is then developed in an alkaline developer, during which the parts originally covered by the mask are removed. The remaining zones consist of the parts which were irradiated through the mask; they project in a relief-like manner from the substrate and represent a negative image of the original mask.
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