Metal Finishing Guide Book

2013

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Table VIII. Standard Acid Copper Baths General formulation: Copper sulfate Sulfuric acid 26-33 oz/gal (195-248 g/L) 4-10 oz/gal (30-75 g/L) Chloride 50-120 ppma Current density 20-100 A/ft2 Semibright plating (Clifton-Phillips): Copper sulfate 33 oz/gal (248 g/L) Sulfuric acid 1.5 oz/gal (11 g/L) Chloride 50-120 ppma Thiourea 0.0001 oz/gal (0.00075 g/L) Wetting agent 0.027 oz/gal (0.2 g/L) Bright plating (Beaver): Copper sulfate Sulfuric acid 28 oz/gal (210 g/L) 8 oz/gal (60 g/L) Chloride 50-120 ppma Thiourea 0.0013 oz/gal (0.01 g/L) Dextrin 0.0013 oz/gal (0.01 g/L) Bright plating (Clifton-Phillips): Copper sulfate Sulfuric acid 26.5 oz/gal (199 g/L) 4 oz/gal (30 g/L) Chloride 50-120 ppma Thiourea 0.005 oz/gal (0.0375 g/L) Molasses 0.1 oz/gal (0.75 g/L) a 10 ml of reagent grade concentrated hydrochloric acid per 100 gallons is equivalent to 12 ppm. sively low current densities can cause copper sulfate buildup, which can cause a reduction in throwing power, and a thick anode film, which can reduce the anode's conductivity. Anode and cathode efficiencies are essentially 100%. Since copper sulfate plating has become of major importance to the industry, a troubleshooting guide is given in this section (see Table X). Standard Acid Copper Plating Table VIII lists the standard formulations for copper sulfate baths. Air agitation or solution sparging with or without mechanical agitation, is recommended. High-Throw Bath The formulation shown in Table IX is used in printed circuit, barrel plating, and other applications where high throwing power is required. For circuit board plating, copper is most commonly plated following an electroless copper metallization of the through holes. Recently, a number of technoloTable IX. High-Throw Acid Copper Bath Copper sulfate 8.0-10.0 oz/gal (60.0-75.0 g/L) Sulfuric acid 25.0-30.0 oz/gal (187-225 g/L) Chloride Proprietary additive(s) 50-100 ppma Per vendor recommendations a 10 ml of reagent grade concentrated hydrochloric acid per 100 gallons is equivalent to 12 ppm. 277

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