Immersion method

Abstract

A composition and method for inhibiting corrosion is disclosed. Metals and metal alloys are treated with compositions which contain inorganic and organic acids that prevent oxide formation on the metals and metal alloys.

1 - 9 . (canceled) 
     
     
         10 . A method comprising:
 a. electrolytically depositing one or more metals on a substrate, the metals are selected from the group consisting of tin and tin alloys, the tin alloys are selected from the group consisting of tin/lead, tin/copper, tin/silver, tin/silver/copper, tin/nickel, tin/bismuth and tin/gold;   b. contacting the one or more metals with a composition composed of one or more inorganic phosphoric acids or salts thereof in amounts of 0.1 gm/L to 1500 gm/L and one or more aminotris(alkylene-phosphoric) acids or salts thereof in amounts of 0.1 gm/L to 0.25 gm/L, and water; and   c. reflowing the one or more metals.   
     
     
         11 . The method of  claim 10 , wherein the composition is contacted with the metals for 5 seconds to 60 seconds. 
     
     
         12 . The method of  claim 11 , wherein the composition is contacted with the metals for 10 seconds to 30 seconds. 
     
     
         13 . The method of  claim 10 , wherein the substrate is a printed wiring board, lead frame, connector, passive component or wafer bump. 
     
     
         14 . A method comprising:
 a. electrolytically depositing a nickel layer on a substrate;   b. electrolytically depositing a tin or tin alloy layer on the nickel layer, the tin alloy is selected from the group consisting of tin/lead, tin/copper, tin/silver, tin/silver/copper, tin/nickel, tin/bismuth and tin/gold;   c. contacting the tin or tin alloy layer with a composition composed of one or more inorganic phosphoric acids or salts thereof in amounts of 0.1 gm/L to 1500 gm/L and one or more aminotris(alkylene-phosphoric) acids or salts thereof in amounts of 0.1 gm/L to 0.25 gm/L, for 5 seconds to 60 seconds and water;   d. reflowing the tin or tin alloy layer at a temperature profile having temperature zones of 125° C. to 180° C. to 240° C. to 260° C. to 240° C.; and   e. cooling the tin or tin alloy layer to room temperature.   
     
     
         15 . The method of  claim 14 , wherein the composition is in contact with the tin or tin alloy layer for 10 seconds to 30 seconds.