Printed circuit board alkaline etching solution suitable for electrolytic copper extraction

Abstract

The invention relates to the technical field of etching solutions, in particular to a printed circuit board alkaline etching solution suitable for electrolytic copper extraction. The alkaline etchingsolution comprises 110-150 g / L of copper chloride, 140-160 g / L of ammonium chloride, 50-150 g / L of ammonium carboxylate, 20-80 g / L of sulfamic acid and 20-30 liters of ammonia water per liter of etching solution, wherein the pH is 7.8-8.8. The printed circuit board alkaline etching solution suitable for electrolytic copper extraction contains the sulfamic acid, so that sulfamic acid chlorine can be formed during electrolysis and used as an oxidation regenerant to regenerate the etching solution on line, and the etching capacity of the etching solution is greatly improved.

Description

technical field [0001] The invention relates to the technical field of etching solutions, in particular to an alkaline etching solution for printed circuit boards suitable for electrolytic copper extraction. Background technique [0002] The etching process of the printed circuit board is to spray the etching solution on the developed copper-clad board, and use the oxidation-reduction reaction between the etching solution and copper to remove the unprotected non-conductor on the patterned printed circuit board made in the previous process. Part of the copper is etched away to form a circuit. [0003] At present, there are two kinds of etching solution systems widely used in industry: acidic copper chloride etching solution and alkaline copper chloride etching solution. Alkaline copper chloride etching solution uses the divalent copper ammonium complex Cu(NH 3 ) 4 Cl 2 As a copper etching agent, and with oxygen, NH 4+ and Cl - Reaction to regenerate the copper etchant. ...

AI Technical Summary

Problems solved by technology

[0026] 2. However, since the existing alkaline copper chloride etching solution contains a large amount of ammonia water, the pH value is relatively high (generally 8.3 to 10), and a large amount of hydroxide ions contained therein will corrode the photosensitive ink resist layer (at pH> Corroded at 7.5) and dry film resist (corroded at pH > 7.8), so only tin-plated circuit boards whose resist does not react with lye can be used for etching

Because the ammonia concentration of the alkaline copper chloride etching solution in the prior art is higher, so the amount of hydrochloric acid that needs to be added is also large, and the amount of ammonium chloride solution produced is relatively large, and it is difficult to completely recycle, and most of them can only be used as Wastewater discharge, resulting in a great waste of resources; therefore, the industry seldom uses acid neutralization method for copper recovery;

[0032] 3. The content of unreacted ammonia water in the alkaline copper chloride etching solution in the prior art is high, and it is easy to volatilize and produce a large amount of ammonia gas

Ammonia gas is an irritating gas. The symptoms of ammonia poisoning caused by mild inhalation include rhinitis, pharyngitis, sore throat, and hoarseness. The earth endangers the health of the staff and causes air pollution

[0033] In summary, the existing alkaline copper chloride etching solution has a corrosive effect on the photosensitive ink resist layer and dry film resist layer, and it is difficult to produce high-quality high-precision circuit boards

In the etching process, it will also cause a series of environmental problems

Especially the existing etching solution will discharge a large amount of copper-containing and ammonia-containing wastewater, seriously polluting the environment

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