Etching solution for composite copper film structure

Abstract

The invention discloses an etching solution for a composite copper film structure. The etching solution comprises a solvent, a first etching agent and a second etching agent, wherein the first etchingagent is dissolved in the solvent, the mass volume ratio of the first etching agent to the solvent is 1:4-1:16, and the first etching agent is at least one of cerous nitrate, ammonium nitrate and cerous ammonium nitrate; the second etching agent is dissolved in the solvent, the volume ratio of the second etching agent to the solvent is 1:1-1:6, and the second etching agent is at least one of sulfuric acid, peroxysulfuric acid and nitrous acid; and the volume mass ratio of the second etching agent to the first etching agent ranges from 1:1 to 1:6. According to the etching solution for the composite copper film structure, a resistance layer area which is not protected by a photoresist can be completely etched by the etching solution, so that a residual resistance layer is avoided. A copperfilm layer cannot be etched by the etching solution, and the processing precision of the composite copper film structure is effectively improved. Meanwhile, the surface appearances and dielectric constants of the copper film and a base material layer are not influenced.

Description

technical field [0001] The invention relates to the technical field of processing composite copper film structures with embedded resistors / capacitors, in particular to an etching solution for composite copper film structures. 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 elec...

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 become thin due to corrosion (etching), 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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