Process for electroless plating tin, lead or tin-lead alloy
AssigneeC. Uyemura & Co., Ltd.
InventorsHiroki Uchida, Motonobu Kubo, Masayuki Kiso, Teruyuki Hotta, Tohru Kamitamari
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Abstract
The invention provides a process for electroless plating tin, lead or tin-lead alloy on copper or copper alloy using an electroless plating bath containing a water soluble tin and/or lead salt, an acid capable of dissolving the salts, and a complexing agent. The tin and/or lead content in the bath is maintained high enough to chemically deposit thick films by replenishing the tin and/or lead salt in proportion to an increase in concentration of copper ion dissolving out in the bath. Also provided is an electroless tin, lead or tin-lead alloy plating process in which a water soluble copper salt is added to a fresh bath.
Claims13
A process for electroless plating tin, lead, or tin-lead alloy comprising the steps of:
- (a) electroless plating tin, lead, or tin-lead alloy on copper or copper alloy using an electroless plating bath comprising a water soluble tin salt, a water soluble lead salt, or a combination thereof, an acid capable of dissolving the salts, and complexing agent;
- (b) analyzing the concentration of copper ion dissolving out in the plating bath during said electroless plating;
- and
- (c) replenishing said water soluble tin salt, water soluble lead salt, or combination thereof in proportion to an increase in said concentration of copper ion dissolving out in the plating bath.
A process for electroless plating tin lead, or tin-lead alloy comprising the steps of:
- (a) adding a water soluble copper salt to a fresh electroless plating bath comprising a water soluble tin salt, a water soluble lead salt, or a combination thereof, an acid capable of dissolving the salts, and a complexing agent;
- (b) electroless plating tin, lead, or tin-lead alloy on copper alloy using said plating bath;
- (c) analyzing the concentration of copper ion dissolving out in the plating bath during said electroless plating;
- and
- (d) replenishing said water soluble tin salt, water soluble lead salt, or combination thereof in proportion to the increase in concentration of copper ion dissolving out in the plating bath.
Dependencies are inferred from the claim text.