US 11,746,433 B2
Single step electrolytic method of filling through holes in printed circuit boards and other substrates
Donald Desalvo, Suzhou (CN); Ron Blake, Oxford, CT (US); Carmichael Gugliotti, Bristol, CT (US); William J. Decesare, Wolcott, CT (US); and Richard Bellemare, Watertown, CT (US)
Assigned to MACDERMID ENTHONE INC., Waterbury, CT (US)
Filed by MacDermid Enthone Inc., Waterbury, CT (US)
Filed on Nov. 5, 2019, as Appl. No. 16/674,052.
Prior Publication US 2021/0130970 A1, May 6, 2021
Int. Cl. C25D 3/38 (2006.01); H05K 3/42 (2006.01); H05K 1/18 (2006.01); H05K 1/02 (2006.01); C25D 5/18 (2006.01); H05K 7/20 (2006.01); C25D 7/00 (2006.01); C25D 5/02 (2006.01)
CPC C25D 3/38 (2013.01) [C25D 5/02 (2013.01); C25D 5/18 (2013.01); C25D 7/00 (2013.01); H05K 1/0206 (2013.01); H05K 1/181 (2013.01); H05K 3/423 (2013.01); H05K 3/424 (2013.01); H05K 7/20154 (2013.01); H05K 2203/0789 (2013.01); H05K 2203/1492 (2013.01)] 23 Claims
OG exemplary drawing
 
1. A method of copper electroplating in the manufacture of printed circuit boards, the method comprising the steps of:
a) preparing an electronic substrate to receive copper electroplating thereon, wherein the electronic substrate comprises one or more features, wherein the one or more features comprise one of one or more through-holes in the electronic substrate; and
b) electroplating copper in the one or more features by contacting the electronic substrate with an acid copper electroplating solution comprising:
a. a source of copper ions;
b. sulfuric acid;
c. a source of chloride ions;
d. a brightener;
e. a wetter or suppressor; and
f. a leveler;
wherein the acid copper electroplating solution is configured for a single-step process, wherein the same acid copper electroplating solution plates the one or more through-holes using a plating cycle until metallization is complete;
wherein the plating cycle comprises the steps of:
i) pulse plating for a first time period using a pulse plating cycle to accelerate copper plating in the middle of the through-holes while minimizing an amount of surface copper plated and, thereafter
ii) direct current plating using uninterrupted forward current in the same copper electroplating solution for a second time period after the step of pulse plating for the first time period;
wherein the pulse plating for the first time period is performed until the middle of the through-holes begin to close and create a copper bridge in the middle of the through holes and then the step of direct current plating using uninterrupted forward current is performed for the second time period to plate the one or more through holes until the one or more through holes are completely metallized.