Combination, method, and composition for chemical mechanical planarization of a tungsten-containing substrate
View Patent ↗A combination, composition and associated method for chemical mechanical planarization of a tungsten-containing substrate are described herein which afford tunability of tungsten/dielectric selectivity and low selectivity for tungsten removal in relation to dielectric material. Removal rates for both tungsten and dielectric are high and stability of the slurry (e.g., with respect to pH drift over time) is high.
1. A method for chemical mechanical polishing of a surface having at least one feature thereon comprising tungsten and at least one feature thereon comprising a dielectric material, said method comprising the steps of:
a. placing a substrate having the surface in contact with a polishing pad;
b. delivering a polishing composition comprising:
an abrasive;
periodic acid; and
an amino alcohol compound; and
c. polishing the substrate with the polishing composition
wherein
said periodic acid and said abrasive are present in a combined amount sufficient to render the substrate surface substantially planar and to maintain a removal rate of tungsten of at least 800 Angstroms per minute upon chemical-mechanical polishing thereof when polishing is done at 4 psi of down force ; and
a tunable tungsten/dielectric selectivity ranging from 0.5 to 1.5 is realized upon chemical-mechanical polishing the substrate using the composition.
2. The method of claim 1 , wherein the dielectric material is a silicon oxide.
3. The method of claim 1 , wherein the amino-alcohol compound is selected from the group consisting of 2-(2-aminoethoxy)ethanol, 2-(2-aminoethylamino)ethanol, diethanolamine, ethanolamine, triethanolamine and mixtures thereof.
4. The method of claim 3 , wherein the amino-alcohol compound is 2-(2-aminoethoxy)ethanol.
5. The method of claim 1 , further comprising a pH-adjusting agent, wherein the composition has a pH ranging from pH 1 to pH 4.
6. The method of claim 1 , wherein the periodic acid is present in an amount from 0.1 weight percent to 5 weight percent.
7. The method of claim 1 , wherein the abrasive is present in an amount from 0.1 to 15 weight percent.
8. The method of claim 1 , wherein the tunable tungsten/dielectric selectivity depends upon the amount of abrasive in relation to the amount of periodic acid.