Etching liquid and method for etching fine lines of flexible circuit board by using same

Abstract

The invention provides etching liquid and a method for etching fine lines of a flexible circuit board by using the same. The etching liquid takes water as a solvent, and comprises the following solutes by concentration: 130g/L-250g/L of copper chloride dehydrate, 100 mL/L-150 mL/L of 30% hydrochloric acid, 26.7g/L-128.4g/L of ammonium chloride, 0.5g/L-16g/L of banking agent and 2g/L-6g/L of secondary solvent, wherein the banking agent is a corrosion inhibitor; the secondary solvent is polyhydric alcohol. The etching liquid is an acid etching liquid which is high in dissolved copper and quick in etching velocity, does not contain hydrogen peroxide or sodium hypochlorite, is low in acid content, and is mixed with the secondary solvent and the banking agent to achieve a purpose of relieving lateral erosion while improving the etching velocity. The method for etching the fine lines of the flexible circuit board by utilizing the etching liquid disclosed by the invention is capable of completing etching more rapidly within short time, straight and flat in etched lines and high in etching factor, and therefore, the method can be used for processing the fine lines of the flexible circuit board.

Description

technical field [0001] The invention relates to the field of PCB production, in particular to an etching solution and a thin-line etching method for a flexible circuit board using the etching solution. Background technique [0002] The production process of printed circuit boards includes: pretreatment → dry film exposure, development → etching → film removal. The etching step includes placing the developed copper-clad laminate in an etching solution, and removing the copper surface of the non-circuit part by utilizing the oxidation-reduction reaction between the etching solution and copper to obtain a complete circuit. [0003] In the etching process, we hope that the etching is vertical, but the effect of the etchant is in all directions. In the actual operation process, the etching effect often attacks the edge of the pattern under the resist. With the agitation of the liquid, the copper It is gradually dissolved, the edge etching expands, and finally the conductor wall ...

AI Technical Summary

Problems solved by technology

[0004] In the etching operation of printed boards, it is desirable to have a higher etching factor, and because of the lightness, thinness, and softness of the flexible circuit board, in order to ensure a higher etching factor during etching, the etching spray pressure should not be too high. Therefore, the etching rate is not fast, and the length of the equipment needs to be designed relatively long, which leads to relatively low production efficiency; and this situation is especially serious when etching thin lines of flexible circuit boards (such as 2 / 2mil specification lines)

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