Tin plating solution

Abstract

To provide a tin plating solution having uniformity of through-hole plating, uniformity of film thickness distribution and no burn deposits even. The tin plating solution include a tin ion source, at least one non-ionic surfactant, imidazoline dicarboxylate and 1,10-phenanthroline.

Description

FIELD OF THE INVENTION[0001]The present invention relates to a tin plating solution, specifically, a tin plating solution used for a matte tin plating of a metal resist for a printed board.BACKGROUND OF THE INVENTION[0002]Tin plating or tin-lead alloy plating has been used for soldering or etching resists. However, according to the recent technical development, wiring pattern of printed board becomes more complex, so that the form of goods to be plated also becomes more complex. As a result, it is required to form uniform plating films on both fine parts and broad parts at same time. Furthermore, when the printed board to be plated has through-holes, the formation of a uniform plated film even within the through-holes is desired.[0003]Since the conventional tin plating solution which can form a uniform plating film inside through-holes contains a strong suppressor, the precipitated particles becomes bigger, and burn deposits, dendritic precipitation or powder precipitation, readily ...

AI Technical Summary

Benefits of technology

[0007]The present invention was devised in light of aforementioned problems with conventional technology. The object of the present invention is to provide a tin plating solution having outstanding uniformity of through-hole plating, outstanding uniformity of film thickness distribution and no burn deposits even in plating for the recent printed boards having complexity of wiring patterns.

[0008]The inventors have researched tin plating solutions and perfected the current invention by discovering that a tin plating solution including the combination of some specific compounds known as a components of plating solution itself achieves uniform film thickness distribution, without burn deposits and with outstanding plating uniformity within through-holes, i.e. throwing power.

Problems solved by technology

However, according to the recent technical development, wiring pattern of printed board becomes more complex, so that the form of goods to be plated also becomes more complex.

Furthermore, lowering the current density reduces burn deposits, but it is not practical because the plating efficiency per time falls.

However, as discussed later, even if non-ionic surfactants are used as the surfactants, the thickness of plating film becomes thin in the section of low current density, so that the film thickness distribution of a plate becomes worse.

However, as discussed later, some compounds with at least two nitrogen atoms described in the patent would still cause the problem of forming a non-uniform plating appearance on a printed board having through-holes.

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