COMPOSITION AND METHOD FOR SELECTIVE OXIDE CMP
A chemical mechanical polishing composition for polishing a substrate having a silicon oxygen material includes a liquid carrier, cubiform ceria abrasive particles dispersed in the liquid carrier, and at least one of an anionic compound and a nonionic compound.
1 . A chemical mechanical polishing composition comprising:
a liquid carrier;
cubiform ceria abrasive particles dispersed in the liquid carrier; and
at least one of an anionic compound and a nonionic compound.
2 . The composition of claim 1 , wherein the cubiform ceria abrasive particles comprise a mixture of cerium oxide and lanthanum oxide.
3 . The composition of claim 1 , wherein the cubiform ceria abrasive particles have a molar ratio of lanthanum to lanthanum plus cerium in a range from about 1 to about 15 percent.
4 . The composition of claim 1 , wherein the cubiform ceria abrasive particles have a BET surface area in a range from about 3 m 2 /g to about 14 m 2 /g.
5 . The composition of claim 1 , wherein the cubiform ceria abrasive particles have an average particle size in a range from about 50 to about 500 nm.
6 . The composition of claim 1 , comprising from about 0.01 to about 2 weight percent of the cubiform ceria abrasive particles at point of use.
7 . The composition of claim 1 , wherein the anionic compound comprises a water-soluble polyelectrolyte, polyanions, polyacids, polyacrylates, poly(vinyl acid), anionic detergents, alkyl or alkyl ether sulfonates and sulfates, alkyl or alkyl ether phosphonates and phosphates, and alkyl or alkyl ether carboxylates.
8 . The composition of claim 1 , wherein the anionic compound is an anionic homopolymer or copolymer and comprises at least one monomer unit selected from acrylic acid, methacrylic acid, maleic acid, vinyl sulfonic acid, sulfate, styrene sulfonic acid and phosphate.
9 . The composition of claim 1 , wherein the anionic compound comprises poly(acrylic acid), poly(methacrylic acid), poly(maleic acid), poly(vinyl sulfonic acid), poly(styrene sulfonic acid), poly(vinyl sulfate), poly(2-acrylamido-2-methyl-1-propanesulfonic acid), poly(vinyl phosphoric acid), poly(methyl methacrylate-co-methacrylic acid, poly(acrylic acid-co-maleic acid), poly(acrylamide-co-acrylic acid), poly(4-styrenesulfonic acid-co-maleic acid), or a combinations thereof.
10 . The composition of claim 1 , wherein the anionic compound is a non-polymeric compound and comprises an alkyl or alkyl aryl sulfate, an alkyl or alkyl aryl sulfonate, an alkyl or alkyl aryl phosphate, an alkyl or alkyl aryl carboxylate, or a combination thereof.
11 . The composition of claim 1 , wherein the anionic compound is dodecylbenzene sulfonic acid, ammonium lauryl sulfate, stearic acid, dihexaphosphate, dodecylphosphoric acid, 1-decanesulfonate, a derivative thereof, an ammonium or sodium salt thereof, or a combination thereof.
12 . The composition of claim 1 , wherein the nonionic compound is a nonionic polymer comprising water-soluble polyethers, polyether glycols, alcohol ethoxylates, polyoxyalkylene alkyl ethers, polyesters, vinyl acrylates, or a combination thereof.
13 . The composition of claim 12 , wherein the nonionic compound is an nonionic homopolymer or copolymer and comprises polyvinyl acetate, polyvinyl alcohol, polyvinyl acetal, polyvinyl formal, polyvinyl butyral, polyvinylpyrrolidone, poly(vinyl phenyl ketone), poly(vinylpyridine), poly(vinylimidazole), poly(acrylamide), polyacrolein, poly(methyl methacrylic acid), polyethylene, polyoxyethylene lauryl ether, polyhydroxyethylmethacrylate, poly(ethylene glycol) monolaurate, poly(ethylene glycol) monooleate, poly(ethylene glycol) distearate, poly(vinyl acetate-co-methyl methacrylate), poly(vinylpyrrolidone-co-vinyl acetate), poly(ethylene-co-vinyl acetate), and combinations thereof.
14 . The composition of claim 1 comprising from about 0.01 weight percent to about 2 weight percent of the anionic compound or the nonionic compound at point of use.
15 . The composition of claim 1 , having a pH in a range from about 4 to about 6 or from about 9 to about 11.
16 . The composition of claim 1 , comprising from about 0.01 to about 2 weight percent of the cubiform ceria abrasive particles at point of use, wherein:
the cubiform ceria abrasive particles comprise a mixture of cerium oxide and lanthanum oxide and have an average particle size in a range from about 50 to about 500 nm;
the anionic compound comprises poly(acrylic acid); and
the composition has a pH in a range from about 4 to about 6.
17 . The composition of claim 1 , comprising from about 0.01 to about 2 weight percent of the cubiform ceria abrasive particles at point of use, wherein:
the cubiform ceria abrasive particles comprise a mixture of cerium oxide and lanthanum oxide and have an average particle size in a range from about 50 to about 500 nm;
the nonionic compound comprises polyvinylpyrrolidone, poly(vinylpyrrolidone-co-vinyl acetate), or a mixture thereof; and
the composition has a pH in a range from about 9 to about 11.
18 . The composition of claim 1 , comprising from about 0.01 to about 2 weight percent of the cubiform ceria abrasive particles at point of use, wherein:
the cubiform ceria abrasive particles comprise a mixture of cerium oxide and lanthanum oxide and have an average particle size in a range from about 50 to about 500 nm;
the anionic compound comprises poly(methacrylic acid), poly(vinyl sulfonic acid), poly(styrene sulfonic acid), poly(2-acrylamido-2-methyl-1-propanesulfonic acid), poly(4-styrenesulfonic acid-co-maleic acid), dodecylbenzene sulfonic acid, or a mixture thereof; and
the composition has a pH in a range from about 9 to about 11.
19 . A method of chemical mechanical polishing a substrate including a silicon oxide dielectric material, the method comprising:
(a) providing a polishing composition comprising (i) a liquid carrier; (ii) cubiform ceria abrasive particles dispersed in the liquid carrier; and (iii) at least one of an anionic compound and a nonionic compound;
(b) contacting the substrate with said provided polishing composition;
(c) moving said polishing composition relative to the substrate; and
(d) abrading the substrate to remove a portion of the silicon oxide dielectric material from the substrate and thereby polish the substrate.
20 . The method of claim 19 , wherein:
the polishing composition comprises from about 0.01 to about 2 weight percent of the cubiform ceria abrasive particles at point of use, the cubiform ceria abrasive particles including a mixture of cerium oxide and lanthanum oxide and having an average particle size in a range from about 50 to about 500 nm;
the anionic compound comprises poly(acrylic acid);
the polishing composition has a pH in a range from about 4 to about 6; and
a removal rate of the silicon oxide dielectric material is at least 1000 Å/min while abrading in (d).
21 . The method of claim 20 , wherein:
the substrate further comprises at least one of a silicon nitride material and a polysilicon material; and
a removal rate selectivity of the silicon oxide dielectric material to the silicon nitride material or the silicon oxide dielectric material to the polysilicon material is greater than about 10:1 in (d).
22 . The method of claim 19 , wherein:
the polishing composition comprises from about 0.01 to about 2 weight percent of the cubiform ceria abrasive particles at point of use, the cubiform ceria abrasive particles including a mixture of cerium oxide and lanthanum oxide and having an average particle size in a range from about 50 to about 500 nm;
the nonionic compound comprises polyvinylpyrrolidone;
the polishing composition has a pH in a range from about 9 to about 11;
the substrate further comprises a silicon nitride material; and
a removal rate selectivity of the silicon oxide dielectric material to the silicon nitride material is less than about 1:1 in (d).
23 . The method of claim 19 , wherein:
the polishing composition comprises from about 0.01 to about 2 weight percent of the cubiform ceria abrasive particles at point of use, the cubiform ceria abrasive particles including a mixture of cerium oxide and lanthanum oxide and having an average particle size in a range from about 50 to about 500 nm;
the anionic compound comprises poly(methacrylic acid), poly(vinyl sulfonic acid), poly(styrene sulfonic acid), poly(2-acrylamido-2-methyl-1-propanesulfonic acid), poly(4-styrenesulfonic acid-co-maleic acid), dodecylbenzene sulfonic acid, or a mixture thereof;
the composition has a pH in a range from about 9 to about 11; and
a removal rate of the silicon oxide dielectric material is at least 3000 Å/min while abrading in (d).
24 . The method of claim 23 , wherein:
the substrate further comprises a silicon nitride material; and
a removal rate selectivity of the silicon oxide dielectric material to the silicon nitride material is less than about 10:1 in (d).
25 . The method of claim 19 , wherein said providing the polishing composition comprises (ai) providing a polishing concentrate and (aii) diluting the polishing concentrate with at least one part water to one part of the polishing concentrate.