Nippondenso Co., Ltd.

Katuhiko Murakawa

Koji Kondo

Futoshi Ishikawa

Nobumasa Ishida

Junji Ishikawa

Kaoru Nomoto

Katsuaki Kojima

Seiji Amakusa

Junji Isikawa

Nobumasa Isida

Disclosed are an electroless copper plating solution comprising a copper ion, a copper ion-complexing agent, a reducing agent and a pH-adjusting agent, the plating solution comprising a trialkanolmonoamine or a salt thereof as a complexing agent and accelerator in an amount giving a higher copper deposition speed than the copper deposition speed obtained when the trialkanolmonoamine or salt thereof is present in an amount sufficient to complex the copper ion but not enough to function as the accelerator, and 1.2.times.10.sup.-4 to 1.2.times.10.sup.-3 mole/l of an iron ion compound as a reaction initiator and/or 1.92.times.10.sup.-4 to 1.92.times.10.sup.-3 mole/l of at least one compound selected from the group consisting of pyridazine, methylpiperidine, 1,2-di-(2-pyridyl)ethylene, 1,2-di-(pyridyl)ethylene, 2,2'-dipyridylamine, 2,2'-bipyridyl, 2,2'-bipyrimidine, 6,6'-dimethyl-2,2'-dipyridyl, di-2-pyridylketone, N,N,N',N'-tetraethylethylenediamine, napththalene, 1,8-naphthyridine, 1,6-naphthyridine, tetrathiafurvalene, .alpha.,.alpha.,.alpha.-terpyridine, phthalic acid, isophthalic acid and 2,2'-dibenzoic acid as an agent for improving the physical properties of a plating film, and a process for forming an electroless copper deposition film by using this electroless copper plating solution.

Electroless copper plating solution and process for formation of copper

Disclosed are an electroless copper plating solution comprising a copper ion, a copper ion-complexing agent, a reducing agent and a pH-adjusting agent, the plating solution comprising a trialkanolmonoamine or a salt thereof as a complexing agent and accelerator in an amount giving a higher copper deposition speed than the copper deposition speed obtained when the trialkanolmonoamine or salt thereof is present in an amount sufficient to complex the copper ion but not enough to function as the accelerator, and 1.2.times.10.sup.-4 to 1.2.times.10.sup.-3 mole/l of an iron ion compound as a reaction initiator and/or 1.92.times.10.sup.-4 to 1.92.times.10.sup.-3 mole/l of at least one compound selected from the group consisting of pyridazine, methylpiperidine, 1,2-di-(2-pyridyl)ethylene, 1,2-di-(pyridyl)ethylene, 2,2'-dipyridylamine, 2,2'-bipyridyl, 2,2'-bipyrimidine, 6,6'-dimethyl-2,2'-dipyridyl, di-2-pyridylketone, N,N,N',N'-tetraethylethylenediamine, naphthalene, 1,8-naphthyidine, 1,6-naphthyridine, tetrathiafurvalene, .alpha.,.alpha.,.alpha.-terpyridine, phthalic acid, isophthalic acid and 2,2'-dibenzoic acid as an agent for improving the physical properties of a plating film, and a process for forming an electroless copper deposition film by using this electroless copper plating solution.

A practically fast electroless copper plating solution is provided by adding a specific monoamine as an accelerator. The accelerator should be a tertiary monoamine and cannot be a diamine, does not have a complexing ability for copper ion, and does not contain a ketone or carboxyl group or an unsaturated group. Specific examples of such monoamines include triethylamine, tripropylamine, tribenzylamine, N-methylpiperidine, and diethylaminoethanol.

Electroless copper plating solution

By forming a first copper layer on a substrate by using a complexing agent for copper ion, which has a low copper complex stability constant, a uniform second layer can be stably formed by a second complexing agent for a copper ion, which has a high copper complex stability constant, even if the substrate is composed of a material having a low catalytic activity, such as tungsten, or even if the catalytic activity of the substrate is uneven. A similar effect can also be obtained by adding a small amount of a complexing agent for a copper ion, having a low stability constant, to an electroless copper plating bath containing a complexing agent for a copper ion, having a low stability constant. In this case, an effect of preventing stopping of the reaction of the complexing agent of a copper ion, having a high stability constant, is attained. Most preferably, after formation of a uniform first copper layer by an electroless copper plating solution containing a complexing agent for a copper ion, having a low stability constant, a second copper layer is formed by an electroless copper plating solution containing a complexing agent for a copper ion, having a high stability constant and also in this case, a small amount of a complexing agent for a copper ion, having a low stability constant, is added.

Process for electrolessly plating copper and plating solution therefor

A practically fast electroless copper deposition is obtained by using a trialkanolmonoamine as a complexing agent for copper ion and as an accelerator, by adding it in an excess amount of 1.2 to 30 times the mole concentration of the copper ion. An optimum increased deposition rate of 100 .mu.m/hr is obtained even if additives such as potassium ferrocyanide, 2,2'-bipyridyl, polyethylenegrycol and an anionic surfactant are added.

Electroless copper plating solution and process for electrolessly

A practically fast electroless copper plating solution is provided by adding a specific monoamine as an accelerator. The accelerator should be a tertiary monoamine and cannot be a diamine, does not have a complexing ability for copper ion, and does not contain a ketone or carboxyl group or an unsaturated group. Specific examples of such monoamines include triethylamine, tripropylamine, tribenzylamine, N-methyl-piperidine, and tris (4-bromophenyl) amine, N-methylmorpholine.

In a chemical copper-plating bath comprising a copper sulfate, a complexing agent, a reducing agent, and a pH-adjusting agent, borofluoride is added to enhance the deposition speed of Cu, thus eliminating the problems of a complicated control of the bath.

Growing community of inventors

Obu, Japan

Katuhiko Murakawa