Method and composition for chemical mechanical planarization of a metal-containing substrate
View Patent ↗A composition and associated method for chemical mechanical planarization of a metal-containing substrate afford low dishing levels in the polished substrate while simultaneously affording high metal removal rates. Suitable metal-containing substrates include tungsten- and copper-containing substrates. Components in the composition include a silatrane compound, an abrasive, and, optionally, a strong oxidizing agent, such as a per-compound.
1. A method for chemical mechanical planarization of a surface having at least one feature thereon comprising a metal, said method comprising the steps of:
A) placing a substrate having the surface having the at least one feature thereon comprising the metal in contact with a polishing pad;
B) delivering a polishing composition comprising:
a) an abrasive;
b) a silatrane compound comprising a polycyclic compound and having at least one silicon atom present in a first bridgehead position and having at least one nitrogen atom present in a second bridgehead position; and
c) an oxidizing agent; and
C) polishing the substrate with the polishing composition.
2. The method of claim 1 wherein the silatrane compound has the structure:
where i, j, and m are each independently 1-4 and X is a substituent or group covalently bonded to the Si atom in the structure.
3. The method of claim 2 wherein the silatrane compound has the structure:
where n=1-6.
4. The method of claim 2 wherein X is selected from the group consisting of C 1 -C 4 -alkyl, C 1 -C 4 -alkoxy, C 1 -C 4 -amino, C 1 -C 4 -amino-alcohol, C 1 -C 4 -carboxylic acid, and C 1 -C 4 -glycol.
5. The method of claim 3 wherein the silatrane compound has the structure:
6. The method of claim 1 wherein the metal is selected from the group consisting of copper and tungsten.
7. The method of claim 6 wherein the metal is tungsten.
8. The method of claim 1 wherein the polishing composition has a pH from about 1 to about 5.
9. The method of claim 1 wherein the oxidizing agent is hydrogen peroxide.