Limiting tin sludge formation in tin or tin/lead electroplating solutions
AssigneeLeaRonal, Inc.
InventorsFred I. Nobel, Barnet D. Ostrow, David N. Schram
Life of this patent
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Abstract
Baths and methods for electroplating tin or tin-lead alloys wherein the formation of tetravalent tin and stannic oxide sludge is reduced or prevented. These baths contain a soluble divalent tin compound, a soluble alkyl or alkylol sulfonic acid at least one wetting agent, and a hydroxyl phenyl compound reducing agent. Other compounds may be added to the bath for improving its performance during electroplating.
Claims21
An electrolyte for limiting the formation of tetravalent tin oxide sludge when electroplating tin or tin-lead alloys therefrom, which electrolyte comprises a soluble divalent tin compound;
- a soluble alkyl sulfonic acid in an amount sufficient to provide a solution having a pH less than about 3;
- at least one wetting agent;
- and resorcinol in an amount sufficient to reduce or prevent the formation of tetravalent tin and stannic oxide sludge when electroplating.
A method for limiting the formation of tetravalent tin sludge in an electrolyte when electroplating tin or tin-lead alloys, which electrolyte comprises a soluble divalent tin compound, methane sulfonic acid in an amount sufficient to provide a solution having a pH less then about 3 and at least one wetting agent;
- which method comprises:
- adding a hydroxyphenyl compound comprising hydroquinone, resorcinol, phloroglucinol, pyrogallol, an amino phenol, hydroquinone sulfuric acid ester, or mixtures thereof, in an amount sufficient to reduce or prevent the formation of tetravalent tin and stannic oxide sludge;
- and
- electroplating a tin or tin-lead alloy upon a substrate at a temperature above about 95.degree. F.
Dependencies are inferred from the claim text.