Reverse pulse plating composition and method

a technology of composition and method, applied in the direction of jewelry, etc., can solve the problems of circuit defects, board rejection, and uneven thickness of coating, and achieve the effects of reducing dog boning, reducing dendrite or whisker formation, and reducing intermittent surface roughness

a technology of composition and method, applied in the direction of jewelry, etc., can solve the problems of circuit defects, board rejection, and uneven thickness of coating, and achieve the effects of reducing dog boning, reducing dendrite or whisker formation, and reducing intermittent surface roughness

US20060081475A1Inactive Publication Date: 2006-04-20SHIPLEY CO LLC
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  • Reverse pulse plating composition and method

Examples

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example 1

Compositions to Reduce or Eliminate Whiskers

[0052] Eight copper metal electroplating baths were prepared to verify the ability of chloride to prevent or reduce whisker (dendrite) formation on copper metal surfaces during electroplating of copper on a substrate. Each electroplating composition or bath was an aqueous bath that contained 80 grams / liter of copper sulfate pentahydrate as the metal ion source, 225 grams / liter of sulfuric acid to maintain the pH of the baths at 4.0. Chloride ion concentration in each of the baths was 25 ppm. The chloride ion source was HCl. In addition to the foregoing components, each bath also contained a carrier component at a concentration of either 0.25 ppm or 1 ppm, and a brightener (BSDS) in an amount of either 0.1 ppm or 0.2 ppm to provide a chloride to brightener ratio of either 125:1 or 250:1. Carriers that were employed in each solution are disclosed in the table below. All of the carriers listed in the table below are block copolymers.

[0053] ...

example 2

Whisker Reduction

[0056] Four electroplating baths were prepared to verify the function of the pulse waveform with respect to the formation for whiskers (dendrites). All four baths contained the same concentration of chemical components, and all substrates were plated using the same anodes, and tank assembly. The anodes were freshly etched prior to each plating experiment. The concentration of inorganic components in each bath was 82 g / L CuSO4•5H2O, 216.5 g / L H2SO4, and the Cl- / brightener ratio was 44. The concentration of suppressor in each bath was 15 ml / l. In a 1.5 liter Haring plating cell, a 15 cm×6.3 cm copper clad panel was electroplated at 10.7 mA / cm2 in each plating bath using a different pulse waveform as shown in the Table. After plating, the boards were physically scanned for whiskers, see Table. As shown in the Table, as the forward wave was made longer, the number of whiskers was reduced significantly. This effect was particularly marked as the forward wave reaches 50 ...

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Abstract

A composition and method for electroplating a metal on a substrate. The composition has a chloride to brightener concentration ratio of from 20:1 to 125:1. The method of electroplating, which employs the composition, employs pulse patterns that improve physical properties of metal surfaces.

Description

BACKGROUND OF THE INVENTION [0001] The present invention is directed to a reverse pulse plating composition and method. More specifically, the present invention is directed to a reverse pulse plating composition and method that reduces brightener decomposition and reduces defects of an electroplated metal layer. [0002] Numerous compositions and methods for electroplating articles with metal layers or coatings are employed in many industries. Such methods may involve passing a current between two electrodes in a plating composition or solution where one of the electrodes is an article to be metal plated. Using an acid copper plating solution for purposes of illustration, a plating solution may contain (1) dissolved copper (cupric ions), usually copper sulfate, (2) an acid electrolyte such as sulfuric acid in an amount sufficient to impart conductivity to the solution, and (3) additives to improve efficiency of the plating reaction and the quality of the metal deposit. Such additives ...

Claims

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Application Information

Patent Timeline
20 Apr 2006
Publication
US20060081475A1
IPC
C25D5/18; C25D3/02; C25D3/38; C25D7/00
CPC
C25D3/02; C25D5/18; C25D3/38
Inventors
BARSTAD, LEON R.; BUCKLEY, THOMAS