Daiwa Fine Chemicals Co., Ltd.

Ebara-udylite Co., Ltd.

Hidenori Tsuji

Keigo Obata

Yoshiaki Okuhama

Masakazu Yoshimoto

Seiichiro Nakao

Shingo Kitamura

Hidemi Nawafune

Masaaki Kamitani

Osamu Masuyama

Toshiharu Naka

Midori Ito

Kim Dong Hyun

Norio Kawachi

A pretreatment solution for providing a catalyst for electroless plating and a pretreatment method using the solution are provided. The pretreatment solution comprises a silver colloidal solution containing, as essential components, at least the following components (I), (II) and (III): (I) silver colloidal particles, (II) one or more ions selected from an ion of a metal having an electric potential which can reduce a silver ion to metal silver in the solution and an ion oxidized at the time of reduction of the silver ion, and (III) one or more ions selected from a hydroxycarboxylate ion, a condensed phosphate ion and an amine carboxylate ion, the silver colloidal particles (I) being produced by the ion of the metal (II) having an electric potential which can reduce a silver ion to metal silver. When an object to be plated is pretreated by use of the pretreatment solution, provision of an effective catalyst for electroless plating is achieved.

Pretreatment solution for providing catalyst for electroless plating, pretreatment method using the solution, and electroless plated film and/or plated object produced by use of the method

A method for forming a circuit pattern includes at least a step (a) of subjecting a non-conductor to electroless copper plating to form a copper film and a step (b) of etching the copper film so as to form a circuit pattern. As a catalyst for the electroless copper plating, a silver colloidal solution is used containing as essential components at least the following: (I) silver colloidal particles; (II) one or more of ions of metal having an electric potential which can reduce silver ions to metal silver in the solution and/or ions which result from oxidation of the ion at the time of reduction of the silver ions; and (III) one or more of hydroxycarboxylate, condensed phosphate and/or amine carboxylate ions. The silver colloidal particles (I) are produced by the ion (II) of the metal having an electric potential which can reduce silver ions to metal silver. The circuit pattern may be formed on a printed wiring board.

Method for forming circuit pattern

An electroplating apparatus capable of forming a film of a uniform thickness on a substrate for printed wiring irrespective of a size of the substrate. Insoluble anode plates are arranged in a plurality of pairs in an electroplating tank in a manner to be juxtaposed to each other along a transfer passage along which the substrate is horizontally transferred and electrically independent from each other for every pair. The insoluble anode plates in each pair are arranged so as to be vertically spaced from each other with the transfer passage being interposed therebetween and are independently connected to an anode terminal of each of rectifiers. Cathode terminals of the rectifiers are electrically connected together to clips for holding the substrate. Electroplating on the substrate is carried out by feeding only the insoluble anode plates contained in a plane of projection of the substrate defined in a vertical direction of the substrate with electricity.

Electroplating apparatus

The present invention includes an aqueous acidic chromate solution, suitable for forming colored chromate coatings on zinc-nickel alloy electrodeposits containing up to about 15% by weight nickel, which solutions have a pH within the range of about 1.3 to about 2.7, a hexavalent chromium concentration of at least 0.5 grams per liter, and preferably about 0.5 to about 100 grams per liter, and which contain sulfate in a weight ratio of SO.sub.4 :Cr.sup.+6 of about 0.025-1.5:1. The zinc-nickel alloy electrodeposits are preferably immersed in the chromating solution for a period sufficient to form the desired colored chromate coating. In some instances, a flash electrodeposit of zinc may be applied to the zinc-nickel alloy electrodeposit before it is immersed in the chromating solution. Alternatively, the zinc-nickel alloy electrodeposit may be immersed in the chromating solution and the solution electrolyzed, with the zinc-nickel alloy surface as the anode, at low current densities for a short period of time, after which, the electrolysis is discontinued and the zinc-nickel alloy surface is maintained in the chromating solution until the desired colored chromate film is formed.

Chromate composition and process for treating zinc-nickel alloys

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Fujisawa, Japan

Hidenori Tsuji