Method For Silver Plating

Abstract

The invention provides a method for silver plating using a non-cyanide acid silver plating bath to form a silver plating film exhibiting good adhesiveness while suppressing dissolution of resist in pattern plating. The method includes conducting strike plating using a non-cyanide acid strike plating bath prior to the silver plating.

1 . A method for silver plating onto a substrate, comprising conducting strike plating onto a substrate using a non-cyanide acid strike plating bath and subsequently conducting silver plating onto the substrate using a non-cyanide acid silver plating bath. 
   
   
       2 . The method according to  claim 1 , wherein both the non-cyanide acid silver plating bath and the non-cyanide acid strike plating bath have a pH of less than 3. 
   
   
       3 . The method according to  claim 1 , wherein the non-cyanide acid strike plating bath is an acid silver strike plating bath or an acid copper strike plating bath. 
   
   
       4 . The method according to  claim 1 , wherein either or both of the non-cyanide acid silver plating bath and the non-cyanide acid strike plating bath contain at least a sulfonate ion. 
   
   
       5 . The method according to  claim 1 , wherein either or both of the non-cyanide acid silver plating bath and the non-cyanide acid strike plating bath contain at least an aliphatic phosphine. 
   
   
       6 . The method according to  claim 3 , wherein the acid copper strike plating bath is used and contains at least a sulfate ion. 
   
   
       7 . The method according to  claim 4 , wherein either or both of the non-cyanide acid silver plating bath and the non-cyanide acid strike plating bath further contain an azole compound and/or a thiophene compound. 
   
   
       8 . The method according to  claim 5 , wherein either or both of the non-cyanide acid silver plating bath and the non-cyanide acid strike plating bath further contain an azole compound and/or a thiophene compound. 
   
   
       9 . The method according to  claim 6 , wherein either or both of the non-cyanide acid silver plating bath and the non-cyanide acid strike plating bath further contain an azole compound and/or a thiophene compound. 
   
   
       10 . The method according to  claim 4 , wherein either or both of the non-cyanide acid silver plating bath and the non-cyanide acid strike plating bath further contain a surfactant or a surface-active polymer compound. 
   
   
       11 . The method according to  claim 5 , wherein either or both of the non-cyanide acid silver plating bath and the non-cyanide acid strike plating bath further contain a surfactant or a surface-active polymer compound. 
   
   
       12 . The method according to  claim 6 , wherein either or both of the non-cyanide acid silver plating bath and the non-cyanide acid strike plating bath further contain a surfactant or a surface-active polymer compound. 
   
   
       13 . The method according to  claim 3 , wherein the method further comprises the step of conducting displacement deposition prevention treatment to the substrate between the strike plating and the silver plating and wherein the strike plating is conducted using the acid copper strike plating bath. 
   
   
       14 . The method according to  claim 1 , wherein the method further comprises the step of conducting pretreatment using an acid degreasing bath prior to the strike plating. 
   
   
       15 . The method according to  claim 1 , wherein either or both of the non-cyanide acid silver plating bath and the non-cyanide acid strike plating bath comprises an ion-exchange membrane therein to separate an anode and a cathode.