Etching solution for composite copper film structure

Abstract

The invention discloses an etchant for a composite copper film structure, including a solvent; a first etchant dissolved in the solvent, and the volume ratio of the first etchant to the solvent is 1:1-1:6; the first etchant is nitric acid and At least one of nitrous acid; the second etchant, dissolved in a solvent, the volume ratio of the second etchant to the solvent is 1:1-1:6; the second etchant is sulfuric acid, peroxysulfuric acid and nitrous acid at least one of; the third etchant, dissolved in a solvent, the volume ratio of the third etchant to the solvent is 1:2-1:21; the third etchant is at least hydrochloric acid, hypochlorous acid and perchloric acid One; the volume ratio of the second etchant, the third etchant and the first etchant is between 1:1:1 and 1:0.25:0.25. The etching solution can completely etch away the resistive layer area not protected by the photoresist, avoids black edges on the edge of the metal circuit on the copper film, does not etch the copper film, and effectively improves the processing accuracy.

Description

technical field [0001] The invention relates to the technical field of processing a composite copper film structure with embedded resistance / capacitance, in particular to an etching solution for a composite copper film structure. Background technique [0002] Engineers with a background in electronics, electrical or computer engineering should have purchased a printed circuit board (PCB) by themselves, and developed, etched and stripped the printed circuit board based on a pre-designed circuit layout (Developing / Etching / Stripping, DES) and other processes, a patterned copper film circuit is produced on the surface of the printed circuit board, which is called a metal circuit. After the fabrication of the metal circuit is completed, predetermined electronic chips and passive components are arranged on the metal circuit, such as amplifiers, processors, resistors, capacitors, inductors, etc., so that the metal circuit, electronic chip and passive components are used to form a ...

AI Technical Summary

Problems solved by technology

Unfortunately, in the process of using ferric chloride to etch the resistance layer, the conductive metal layer will be corroded (etched) and thinned, resulting in an increase in the line resistance of the metal circuit formed by the patterned conductive metal layer. In severe cases, the metal circuit will also appear disconnected, that is to say, the existing etching solution will affect the processing accuracy of the composite copper film structure

In addition, ferric chloride, as the main etchant of the resistance layer made of metal alloy or metal compound, will also make the edge of the patterned resistance layer form a bevel, that is, the cross section of the formed metal line will be trapezoidal and Irregular rectangle, so that when looking down on the metal circuit of the composite copper film structure, the edge of the metal circuit will appear black edge shown by the above-mentioned oblique angle, which seriously affects the processing accuracy

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