Composition and method for enhancing pot life of hydrogen peroxide-containing CMP slurries
A method for providing CMP slurries for copper CMP that have improved pot life by ameliorating hydrogen peroxide degradation in slurries. The method comprises a composition that has a transition metal content of less than about 5 parts per million (ppm), preferably less than about 2 ppm. Preferably the method comprises a composition containing less than about 2 ppm of yttrium, zirconium, and/or iron.
1 . A method for enhancing the pot life of a chemical-mechanical polishing (CMP) slurry during semiconductor wafer planarization, which comprises maintaining the amount of transition metals in the slurry at a value of less than about 5 part per million (ppm) prior to initiating planarization.
2 . The method of claim 1 wherein the transition metal content is maintained at less that about 2 ppm.
3 . The method of claim 1 wherein the amount of any transition metal selected from Groups 3, 4, and 8 of the Periodic Table present in the slurry is maintained at less than about 1 ppm.
4 . The method of claim 3 wherein the transition metal is selected from the group consisting of yttrium, zirconium, and iron.
5 . The method of claim 1 wherein the total amount of transition metals selected from Groups 3, 4, and 8 of the Periodic Table present in the slurry is maintained at less than about 2 ppm.
6 . The method of claim 1 wherein the amount of any transition metal from Group 3 and Group 4 of the Periodic Table is maintained at an amount of less than about 1 ppm.
7 . The method of claim 1 wherein the amount of zirconium present in the slurry is maintained at a value of less than about 1 ppm.
8 . The method of claim 1 wherein the amount of zirconium in the slurry is maintained at an amount of less than about 0.1 ppm.
9 . The method of claim 1 wherein the amount of iron in the slurry is maintained at an amount of less than about 1 ppm.
10 . The method of claim 1 further comprising maintaining the pH of the slurry at a value of about 7 or less.