Acid copper electroplating bath and method for electroplating low internal stress and good ductility copper deposits

Abstract

Acid copper electroplating baths provide improved low internal stress copper deposits with good ductility. The acid copper electroplating baths include one or more polyallylamines and certain sulfur containing accelerators. The acid copper electroplating baths may be used to electroplate thin films on relatively thin substrates to provide thin film copper deposits having low internal stress and high ductility.

What is claimed is: 
     
         1 . An acid copper electroplating bath comprising one or more sources of copper ions, one or more electrolytes, one or more polyallylamines, one or more of (O-ethyldithiocarbonato)-S-(3-sulfopropyl)-ester, acids thereof or its alkali metal salts and one or more suppressors. 
     
     
         2 . The acid copper electroplating bath of  claim 1 , wherein the one or more polyallylamines have weight average molecular weights of 1000 g/mole or greater. 
     
     
         3 . The acid copper electroplating bath of  claim 1 , wherein the one or more polyallylamines are in amounts of 1 to 10 ppm. 
     
     
         4 . The acid copper electroplating bath of  claim 1 , wherein the one or more (O-ethyldithiocarbonato)-S-(3-sulfopropyl)-ester, acids thereof or its alkali metal salts are in amounts of 100 ppm to 300 ppm. 
     
     
         5 . A method comprises:
 a) contacting a substrate with a copper electroplating bath comprising one or more sources of copper ions, one or more electrolytes, one or more branched polyallylamines, one or more of (O-ethyldithiocarbonato)-S-(3-sulfopropyl)-ester, acids thereof or its alkali metal salts and one or more suppressors; and   b) electroplating low internal stress high ductility copper on the substrate from the copper electroplating bath.   
     
     
         6 . The method of  claim 5 , wherein the low internal stress high ductility copper has a thickness of 1 μm to 5 mm. 
     
     
         7 . The method of  claim 5 , wherein the substrate a flexible circuit board, flexible circuit antenna, REID tag, electrolytic foil or semiconductor. 
     
     
         8 . A copper film having an initial internal stress from 0 psi to 950 psi and an internal stress after ageing from 300 psi to 900 psi and an elongation of 8% or greater at loads of maximum tensile stress of 50 lbf or greater.