US 9,809,883 B2
Formaldehyde free electroless copper plating compositions and methods
Andy Lok-Fung Chow, Fanling (CN); Dennis Kwok-Wai Yee, Fanling (CN); and Crystal P. L. Li, Fanling (CN)
Assigned to Rohm and Haas Electronic Materials LLC, Marlborough, MA (US)
Filed by Rohm and Haas Electronic Materials LLC, Marlborough, MA (US)
Filed on Jul. 10, 2015, as Appl. No. 14/796,459.
Application 14/796,459 is a division of application No. 13/769,332, filed on Feb. 17, 2013, granted, now 9,611,550.
Claims priority of provisional application 61/746,112, filed on Dec. 26, 2012.
Prior Publication US 2015/0376795 A1, Dec. 31, 2015
Int. Cl. H01B 1/02 (2006.01); C23C 18/40 (2006.01); C09D 1/00 (2006.01); H05K 3/18 (2006.01)
CPC C23C 18/40 (2013.01) [C09D 1/00 (2013.01); H05K 3/187 (2013.01); H01B 1/02 (2013.01)] 1 Claim
 
1. A method comprising:
a) providing a printed wiring board comprising a plurality of through-holes;
b) desmearing the through-holes; and
c) depositing copper on walls of the through-holes using an electroless copper composition consisting of one or more sources of copper ions, one or more chelating agents selected from the group consisting of polycarboxylic acids, salts thereof, polyaminocarboxylic acids and salts thereof, water, optionally one or more stabilizers selected from the group consisting of amines, alkanolamines, thioamides, azoles and salts thereof, optionally one or more surfactants, and one or more reducing agents having formula:

OG Complex Work Unit Drawing
wherein Xy+ is a neutralizing counter cation of formula (I), where y+ is an integer of one or greater and Xy+ may be H+, ammonium cation, quaternary ammonium cation, sulfonium cation, phosphonium cation, pyradinium cation, monovalent metal cation, multivalent metal cation or divalent organometallic cation;
R and R′ are independently hydrogen, carboxyl, carboxyalkyl, sulfonate, sulfoxide, unsubstituted, linear or branched alkyl, sulfinate; substituted or unsubstituted aryl;
Z is chosen from unsubstituted, linear or branched (C1-C6)alkyl, acetyl or substituted or unsubstituted (C6-C10) aryl; m is an integer of 1 to 6; and n is 1; and the composition is free of formaldehyde.