Difference etching solution for semi-additive process preparation fine line

Abstract

The present invention provides a difference etching solution for a semi-additive process preparation fine line. The difference etching solution comprises two parts: basic solution and difference etching additive, wherein the basic solution is vitriol and hydrogen peroxide, and the difference etching additive includes a hydrogen peroxide stabilizer, a flat etchant protective agent, a gloss agent and a roughness control agent. Compared with the prior art, the difference etching solution for semi-additive process preparation fine line is able to effectively remove the base copper and effectively reduce the lateral erosion. The difference etching solution for a semi-additive process preparation fine line employs a lateral erosion protective agent so as to greatly reduce the generation of Undercut, improve the line yield rate, effectively protect the line corner angle and maintain the rectangular morphology of the line cross section; and the difference etching solution for the semi-additive process preparation fine line employs additives such as a microetching detergent, a roughness control agent and the like so as to perform further control of the line microscopic morphology of the line after difference etching, obtain visual sense shine and cleaning and facilitate subsequent process connection because of the roughness of 0.2-0.5[Mu]m in the microscopic scale.

Description

technical field [0001] The invention relates to a differential etching solution used in the preparation of high-precision circuits by a semi-additive (Semi-additive process, SAP) process. Background technique [0002] Etching is an important process for preparing circuits in the field of printed circuit boards and semiconductors. It is difficult to prepare fine circuits with a line width / space below 20μm / 20μm by ordinary etching processes. Usually, such circuits can only be prepared by semi-additive methods. The specific process is as figure 1 shown. [0003] However, the conventional differential etching solution uses a copper-reducing solution, which has a strong side erosion effect on the copper surface after pattern electroplating, and the solution is more likely to attack the side wall of the circuit, and because the selectivity of the copper-reducing solution is not strong enough, in real In the current SAP process, it is difficult to only etch the bottom copper, but...

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Problems solved by technology

[0003] However, the conventional differential etching solution uses a copper-reducing solution, which has a strong side erosion effect on the copper surface after pattern electroplating, and the solution is more likely to attack the side wall of the circuit, and because the selectivity of the copper-reducing solution is not strong enough, in real In the current SAP process, it is difficult to etch only the bottom copper, while having good protection for the circuit or a relatively slow etching effect

Therefore, the use of copper-reducing solution for differential etching process can easily lead to floating of a large number of lines, which is called Undercut in the industry, and it is difficult to improve the yield rate, especially for the preparation of fine lines with line width / line spacing below 20μm / 20μm. Ordinary copper-reducing solution The yield rate of this kind of fine lines is extremely low

In addition, during differential etching, the edges and corners of the line are bitten by the etching solution in two directions. If there is no protection mechanism, the rectangular shape of the line cross-section will not be maintained, making it difficult to control the impedance of high-frequency lines.

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