Etching solution and application thereof

Abstract

The invention relates to an etching solution and application thereof. The etching solution comprises water, chloride, inorganic acid, organic acid and an oxidizing agent; the chloride is selected from at least one of sodium chloride, potassium chloride, copper chloride, ammonium chloride and hydrogen chloride; the inorganic acid is selected from at least one of nitric acid, sulfuric acid, phosphoric acid and perchloric acid; the organic acid is selected from at least one of iminodiacetic acid, formic acid, acetic acid, butyric acid, citric acid, isocitric acid, oxalic acid and malonic acid; the oxidizing agent is selected from at least one of hydrogen peroxide, sodium persulfate, ammonium persulfate, potassium persulfate, ammonium ceric nitrate, sodium ceric nitrate, potassium ceric nitrate, sodium hypochlorite and potassium hypochlorite; and the molar ratio of the chloride to the inorganic acid to the oxidizing agent is (55-70): (30-50): 1. The etching solution can quickly etch nickel, chromium or nickel-chromium alloy, has a small etching effect on copper, meets the process requirements of manufacturing fine lines in flexible printed circuit boards and integrated circuits at present, and is safe and reliable.

Description

technical field [0001] The invention relates to the field of metal etching, in particular to an etching solution and its application. Background technique [0002] With the continuous development of electronic products, especially the rapid development of wearable and portable electronic products, higher requirements are put forward for the circuit boards used. The circuit boards need to be light, small and bendable. Flexible printed circuit (FPC, Flexible Printed Circuit) has the advantages of small size, light weight and bendability, making it quickly become an important development direction of circuit board technology, and its market share is also increasing. [0003] At present, polyimide (Polyimide) substrates are widely used in flexible circuit boards. In the process of making circuit boards, in order to enhance the adhesion between the metal circuit and the polyimide base film, and at the same time as the seed layer of the copper circuit, a layer is usually formed b...

AI Technical Summary

Problems solved by technology

However, in the circuit etching technology adopted today, copper etchant is usually used to etch the copper and nickel-chromium alloy layers at the same time, because the etching rate of copper etchant to nickel and chromium metal is relatively slow, and the copper etching solution on both sides of the bottom of the copper circuit , the replacement efficiency of the etchant is low, so it is difficult to etch the seed layer on both sides of the bottom of the copper line, causing the bottom of the line to expand

When making high-density circuits, the residual nickel and chromium metal seed layer on the edge of the circuit increases the risk of copper circuit short circuit and affects the yield of flexible circuit boards

If the seed layer exposed at the bottom of the line is removed by increasing the etching time, it will cause severe undercutting of the copper line

[0004] Existing nickel-chromium metal etching solution mainly contains the etching solution of cupric chloride system and ferric chloride system, wherein the nickel-chromium alloy etching solution of copper chloride system etch The coefficient is small and the efficiency is low; the nickel-chromium alloy etching solution of the ferric chloride system has a large etching coefficient, but the side corrosion of copper is relatively serious

[0005]In addition, the existing etching solution systems all have problems such as poor adjustment of etching rate, uncontrollable etching morphology quality, and poor etching repeatability; And the etchant of existing formula is relatively thick to some, or some nickel-chromium alloys (containing nickel or chromium of specific mass percentage range) etch poorly, and the residual of nickel-chromium alloy is too much

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