Daiwa Fine Chemicals Co., Ltd.

Other

Harima Chemicals, Incorporated

Ishihara Chemical Co., Ltd.

Sumitomo Electric Industries, Limited

Takao Takeuchi

Keigo Obata

Hidemi Nawafune

Yoshiaki Okuhama

Kiyotaka Tsuji

Tetsuji Nishikawa

Masatoshi Majima

Shinji Inazawa

Kazuki Ikeda

Masakazu Yoshimoto

Ayao Kariya

Seiichiro Nakao

Shigeyoshi Nakayama

Yasuhito Kohashi

Naoya Inoue

Dong-Hyun Kim

Hiroshi Tanaka

Hisao Irie

Seishi Masaki

Shunsuke Ishikawa

Takaaki Anada

Emiko Tanaka

Shigeru Takatani

Masayuki Nishino

Yuji Kato

Tetsuya Kondo

Keiji Shiomi

Kyoko Kuba

Mitsuo Komatsu

Yoshiharu Matsuda

To develop stable, non-cyanide silver and silver alloy plating baths. The present invention is a silver and silver alloy plating bath, comprises: (A) a soluble salt, comprising a silver salt or a mixture of a silver salt and a salt of a metal selected from the group consisting of tin, bismuth, cobalt, antimony, iridium, indium, lead, copper, iron, zinc, nickel, palladium, platinum, and gold; and (B) at least one aliphatic sulfide compound comprising a functionality selected from the group consisting of an ether oxygen atom, a 3-hydroxypropyl group, and a hydroxypropylene group, with the proviso that the aliphatic sulfide compound does not comprise a basic nitrogen atom.

Silver and silver alloy plating bath

A flux contains resin having film forming ability, activator, solvent and at least one complex selected from silver complex and copper complex. The flux is used when soldering is performed onto a circuit having electroless nickel plating or further having gold plating on the electroless nickel plating. Allowing a barrier layer of silver or copper to deposit on the surfaces of lands suppresses the diffusion of nickel into the melted solder alloy during soldering, and also prevents phosphorous concentration. This improves the bonding strength of soldering and suppresses the reduction deposition of silver and/or copper to portions other than circuit patterns.

Flux for soldering and circuit board

A silver and silver alloy plating bath, includes (A) a soluble salt, having a silver salt or a mixture of a silver salt and a salt of a metal such as tin, bismuth, indium, lead, and the like; and (B) a particular aliphatic sulfide compound, such as thiobis(diethyleneglycol), dithiobis(triglycerol), 3,3'-thiodipropanol, thiodiglycerin, 3,6-dithiooctane-1,8-diol, and the like, which contain at least one or more of an ether oxygen atom, a 1-hydroxypropyl group, a hydroxypropylene group, or two or more of a sulfide bond in the molecule, and not containing a basic nitrogen atom. Compared to baths containing aliphatic monosulfide compounds, such as thiodiglycol or beta-thiodiglycol, which do not contain an ether oxygen atom, 1-hydroxypropyl group, a hydroxypropylene group, or two or more of a sulfide bond in the molecule, by having these particular compounds, the plating bath of the present invention has excellent stability over extended time, excellent co-deposition of silver and various metals, and excellent appearance of the electrodeposition coating.

According to present invention, there is provided a lead-free solder precipitating composition comprising a tin powder, and a complex of silver ions and/or copper ions and aryl phosphines, alkyl phosphine, phosphines or azoles. The solder precipitating composition can form proper lead-free solder on lands of a circuit board, without forming silver and/or copper film on the circuit board.

Solder precipitating composition

To provide a plating method, which enables wide industrial use of the redox system electroless plating method having excellent characteristics, and a plating bath precursor which is preferable for the plating method. The plating method comprises a process oxidizing first metal ions of a redox system of a plating bath from a lower oxidation state to a high oxidation state, and second metal ions of said redox system are reduced and deposited onto the surface of an object to be plated, wherein a process is provided in which by supplying the electrical current to the plating bath, the first metal ions are reduced from said lower oxidation state to thereby activate the plating bath. The plating bath precursor is formed stabilizing the plating bath so that reduction and deposition of the second metal ions substantially do not occur in order to improve its storing performance.

Plating method and plating bath precursor used therefor

The present invention provides a tin-copper alloy plating bath, tin-copper-bismuth alloy plating bath or tin-copper-silver alloy plating bath containing a soluble metal compound and a specific sulfur-containing compound. The plating bath of the present invention is an alloy plating bath containing tin and copper, the bath being capable of preventing deposition of copper on a tin anode by substitution, having low dependence of plated coating composition on current density, high bath stability and resistance to turbidness.

Plating bath and process for depositing alloy containing tin and copper

Redox system electroless plating method

An aqueous solution for obtaining a noble metal by chemical reduction containing at least one water-soluble compound or complex of a metal selected from the group consisting of gold, platinum, silver, and palladium as a source of the metal to be deposited, and at least one mercapto compound or sulfide compound or a salt thereof as a reducing agent. The reducing agent is typically mercaptoacetic acid, 2-mercaptopropionic acid, 2-aminoethanethiol, 2-mercaptoethanol, glucose cysteine, 1-thioglycerol, sodium mercaptopropanesulfonate, N-acetylmethionine, thiosalicylic acid, 2-thiazoline-2-thiol, 2,5-dimercapto-1,3,4-thiadiazole, 2-benzothiazolethiol, or 2-benzimidazolethiol. They may be used singly or in combination.

Aqueous solutions for obtaining noble metals by chemical reductive deposition

Aqueous solutions for obtaining metals by reductive deposition

An electrolytic process for producing lead and tin sulfonates which comprises applying a DC voltage to an anode and a plurality of cathodes in an electrolytic cell and thereby dissolving lead or tin in an electrolytic solution. The electrolytic cell is partitioned by cation- and anion-exchange membranes into anode and cathode chambers. The electrolytic solution is a solution of an organic sulfonic acid, and the anode is lead or tin. The process reduces contents of radioisotopes such as uranium and thorium to a level of less than 50 ppb, and therefore the coatings formed by solder plating using the lead and tin salts in accordance with the invention show radioactive .alpha. particle counts of less than 0.1 CPH/cm.sup.2.

Electrolytic process for producing lead sulfonate and tin sulfonate for

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Akashi, Japan

Takao Takeuchi