Methods to stop copper attach by alkaline etching agents such as ammonia and monoethanol amine (MEA)
A corrosive composition, such as an alkaline aqueous carbon dispersion, a cleaner, a cleaner conditioner, or a conditioner, comprises a corrosion inhibitor, e.g., benzotriazole. The corrosion inhibitor is present in an amount effective to reduce or stop the dissolution of metal from a metallic surface, such as a printed circuit board, in contact with the composition. A method to reduce or stop the dissolution of metal from a metallic surface in contact with a corrosive composition, and a method to stabilize or recover a corrosive composition containing metal contaminants by adding an effective amount of a corrosion inhibitor to the corrosive composition.
1 . A method to reduce the dissolution of metal from a metallic surface in a corrosive composition, comprising:
providing a corrosive composition;
adding an effective amount of a corrosion inhibitor to said corrosive composition to reduce its corrosiveness; and
applying said composition to said metallic surface.
2 . The method of claim 1 wherein said amount of said corrosion inhibitor is from about 1 ppm to about 1% by weight.
3 . The method of claim 1 wherein said amount of said corrosion inhibitor is from about 50 ppm to about 4000 ppm by weight.
4 . The method of claim 1 wherein said amount of said corrosion inhibitor is from about 200 ppm to about 600 ppm by weight.
5 . The method of claim 1 wherein said corrosion inhibitor is at least one of an imidazole, a triazole, an indole, an azole, a thiazole, or a tetrazole.
6 . The method of claim 1 wherein said corrosion inhibitor is selected from the group consisting of benzotriazole, sodium mercaptobenzothiazole, thiourea, tolyltriazole, 3-amino-1,2,4-triazole, and combinations thereof.
7 . The method of claim 1 wherein said metal is copper.
8 . A method to stabilize or recover a corrosive composition, comprising:
presenting a corrosive composition;
presenting a metallic surface to said corrosive composition under conditions effective to dissolve metal from said metallic surface;
dissolving metal from said metallic surface in said corrosive composition;
adding a corrosion inhibitor to said corrosive composition in an amount effective to stabilize or recover said corrosive composition.
9 . The method of claim 8 wherein said corrosion inhibitor is added to prevent gel formation in said corrosive composition.
10 . The method of claim 8 wherein said corrosion inhibitor is added after gel formation has occurred in said corrosive composition.
11 . The method of claim 10 wherein said corrosion inhibitor is added in an amount effective to at least partially reverse said gel formation.
12 . The method of claim 8 wherein said amount of said corrosion inhibitor is from about 1 ppm to about 1% by weight.
13 . The method of claim 8 wherein said amount of said corrosion inhibitor is from about 50 ppm to about 4000 ppm.
14 . The method of claim 8 wherein said amount of said corrosion inhibitor is from about 200 ppm to about 600 ppm
15 . The method of claim 8 wherein said corrosion inhibitor is at least one of an imidazole, a triazole, an indole, an azole, a thiazole, or a tetrazole.
16 . The method of claim 8 wherein said corrosion inhibitor is selected from the group consisting of benzotriazole, sodium mercaptobenzothiazole, thiourea, tolyltriazole, 3-amino-1,2,4-triazole, and combinations thereof.
17 . The method of claim 8 wherein said metal is copper.