Copper etching liquid

Abstract

The purpose of the present invention is to provide a copper etching liquid which is capable of reliably suppressing galvanic corrosion, while achieving easy bath control and excellent etching rate. Inorder to achieve the above-described purpose, the present invention provides a copper etching liquid which is composed of an alkaline aqueous solution, and which is characterized by containing 1-70 g / L of copper, 10-500 g / L of ammonia water in terms of 25% ammonia water and 5-500g / L of an ammonium salt. This copper etching liquid is also characterized in that the ammonium salt is composed of oneor more ammonium salts that are selected from the group consisting of an ammonium salt of an inorganic acid, an ammonium salt of a sulfonic acid, an ammonium salt of a saturated fatty acid, an ammonium salt of an aromatic carboxylic acid, an ammonium salt of a hydroxy acid and an ammonium salt of a dicarboxylic acid.

Description

technical field [0001] The invention relates to a copper etching solution. Background technique [0002] Conventionally, as a formation method of a circuit pattern, after forming a resist on the board|substrate which provided the copper foil of about 20 micrometers in the whole surface, the subtraction process of etching and removing the exposed copper foil is known. In addition, as a method for forming a finer circuit pattern, it is known to form a seed crystal layer on the surface of a resin substrate by electroless copper plating, provide a plating resist on the seed crystal layer, form a circuit by electrolytic copper plating, and then etch it. A semi-additive process (SemiAdditive Process, SAP) for removing the seed layer remaining on the substrate between the circuits, etc. [0003] In the semi-additive process, as a copper etching solution for etching and removing the seed layer, that is, electroless copper plating, for example, sulfuric acid / hydrogen peroxide type (...

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Problems solved by technology

[0005] However, when copper that conducts with a metal more expensive than copper is etched with the copper etchant described in Patent Documents 1 to 5, the copper that conducts with the metal that is more expensive than copper is compared with the copper that does not conduct with the expensive metal. Etching of copper is accelerated (galvanic corrosion)

As a result, as the circuit becomes thinner, the resistance of the circuit increases or the circuit is disconnected, and even the dissolution of the circuit is accelerated and disappears, and then the plating layer of the above-mentioned expensive metal provided on the surface of the circuit peels off (disappears).

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