CMP compositions selective for oxide and nitride with high removal rate and low defectivity
The invention provides a chemical-mechanical polishing composition containing a ceria abrasive, one or more nonionic polymers, optionally one or more phosphonic acids, optionally one or more nitrogen-containing zwitterionic compounds, optionally one or more sulfonic acid copolymers, optionally one or more anionic copolymers, optionally one or more polymers comprising quaternary amines, optionally one or more compounds that adjust the pH of the polishing compositions, water, and optionally one or more additives. The invention further provides a method of chemically-mechanically polishing a substrate with the inventive chemical-mechanical polishing composition. Typically, the substrate contains silicon oxide, silicon nitride, and/or polysilicon.
1. A method of chemical-mechanical polishing of a substrate comprising:
(i) contacting a substrate comprising silicon oxide and polysilicon with a polishing pad and a chemical-mechanical polishing composition consisting essentially of
(a) a ceria abrasive,
(b) one or more nonionic polymers selected from the group consisting of polyalkylene glycols, polyetheramines, polyethylene oxide/polypropylene oxide copolymers, polyacrylamide, polyvinylpyrrolidone, siloxane polyalkyleneoxide copolymers, hydrophobically modified polyacrylate copolymers, hydrophilic nonionic polymers, polysaccharides, and mixtures thereof,
(c) picolinic acid,
(d) optionally one or more phosphonic acids,
(e) optionally one or more sulfonic acid copolymers,
(f) one or more anionic copolymers,
(g) optionally one or more polymers comprising quaternary amines,
(h) optionally one or more compounds that adjust the pH of the polishing composition, and
(i) water;
(ii) moving the polishing pad relative to the substrate with the chemical-mechanical polishing composition therebetween; and
(iii) abrading at least a portion of the substrate to remove silicon oxide and polysilicon therefrom and to polish the substrate.
2. The method of claim 1 , wherein the removal of silicon oxide from the substrate is at a rate greater than the removal of polysilicon from the substrate.
3. The method of claim 1 , wherein the substrate further comprises silicon nitride, and the abrading of at least a portion of the substrate removes silicon nitride therefrom.
4. The method of claim 3 , wherein the removal of silicon oxide from the substrate is at a rate greater than the removal of silicon nitride from the substrate.
5. The method of claim 1 , wherein picolinic acid is present at the point-of-use in an amount of from about 1 ppm to about 1000 ppm.
6. The method of claim 1 , wherein one or more phosphonic acids are present in the chemical-mechanical polishing composition.
7. The method of claim 1 , wherein one or more sulfonic acid copolymers are present in the chemical-mechanical polishing composition.
8. The method of claim 1 , wherein one or more polymers comprising quaternary amines are present in the chemical-mechanical polishing composition.
9. The method of claim 1 , wherein one or more compounds that adjust the pH the polishing composition are present in the chemical-mechanical polishing composition.
10. The method of claim 1 , wherein one or more phosphonic acids, one or more sulfonic acid copolymers, one or more anionic copolymers, one or more polymers comprising quaternary amines, and one or more compounds that adjust the pH the polishing composition are present in the chemical-mechanical polishing composition.