Nickel-gold plateable thick film silver paste, and plating process for low temperature co fired ceramic devices and ltcc devices made therefrom

Abstract

Described are LTCC devices, with external silver containing electrical contacts, that are sequentially plated with a nickel containing metal and a gold containing metal.

1 . A process to plate metal onto an LTCC device comprising the sequential steps of:
 a. electrolessly plating at a pH between 4-12 preferably between 4-9 a nickel containing metal onto silver containing metal external electrical contacts of an LTCC device, wherein the plating thickness of the nickel containing metal is 100-300 micro-inches,   b. plating a gold containing metal onto the nickel containing metal wherein said plating is selected from the group consisting of electrolessly plating and immersion plating, wherein the plating thickness of the gold containing metal is 20-100 micro-inches.   
     
     
         2 . A process to plate metal onto an LTCC device of  claim 1 , wherein the metal external electrical contacts is formed from a silver paste composition consisting essentially of, based on weight percent, 75-90% silver powder of different sizes and shapes, optionally 0.5-4% glasses and the balance organic medium. 
     
     
         3 . A process to plate metal onto an LTCC device of  claim 2 , wherein the glass is an alumino-borosilicate glass as “network formers” with Zn, Ba, Mg, Sr, Sn, Ti, Na ions as “net-work modifying cations”. 
     
     
         4 . A process to plate metal onto an LTCC device of  claim 2 , wherein the glass comprises 20.2% SiO 2 , 2.8% Al 2 O 3 ; 20.4 B 2 O 3 ; 10.1 ZnO; 19.0% BaO; 3.1% MgO; 3.3% Na 2 O; 13.7% SrO; 5.5% TiO 2 ; and 1.9% SnO 2 . 
     
     
         5 . A process to plate metal onto an LTCC device of  claim 2 , wherein the plating thickness of the nickel containing metal is 100-150 micro-inches, and wherein the plating thickness of the gold containing metal is 20-60 micro-inches.