Technique for local copper thinning and precision circuit making of printed circuit boards

Abstract

The invention provides a technique for local copper thinning and precision circuit making of printed circuit boards. The technique includes the following steps: adhering a dry film to a coppering surface region, with on need for copper reduction, of one printed circuit board with holes and subjected to electroplating; by adopting a brownification mode, subjecting the position exposing the copper surface and needing precision circuit making to copper thinning to the thickness range of 20+ / -5um; removing the dry film; removing the protruding parts of the joints of the dry film and the holes. According to the technique, the method of dry film isolating copper thinning is adopted, the thickness after copper plating of the holes is guaranteed, and the problem of under etching of the made precision circuit due to too thick surface copper is avoided.

Description

technical field [0001] The invention belongs to the field of processing and manufacturing of printed circuit boards, and in particular relates to a process method for locally thinning copper and precision circuit production of printed circuit boards. Background technique [0002] In the production process of printed circuit boards, the normal product requires a minimum copper thickness of 18um, but after actual electroplating, the minimum copper thickness of the hole is 20um, plus the thickness of the bottom copper 8um, the copper thickness of the hole after normal electroplating reaches 30±5um , far exceeding the ideal hole copper thickness of 20±5um for making 2mil lines. When it is necessary to manufacture precision circuits on the product, if the copper thickness on the circuit board surface is reduced, the copper thickness of the holes will also be reduced accordingly, which cannot meet the requirements of the copper thickness of the holes; however, the copper thickness...

AI Technical Summary

Problems solved by technology

[0004] In order to solve the above-mentioned problems that the local copper thinning of the printed circuit board and the production of the precision circuit are complicated, the production efficiency is low, the requirements of the thickness of the copper on the hole and the thickness of the surface copper of the printed circuit board cannot be met at the same time, and it is not convenient for the manufacture of the precision circuit, the present invention Provides a process method for local copper thinning of printed circuit boards and precision circuit production, which has simple procedures, high production efficiency, can meet the thickness requirements of printed circuit board hole copper and surface copper, and is convenient for precision circuit manufacturing

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