CMP processing composition comprising alkylamine and cyclodextrin
Described are compositions useful in methods for chemical-mechanical processing a surface of a substrate, especially a substrate that contains dielectric material, wherein the composition contains cyclodextrin and an alkylamine.
1. A chemical-mechanical planarization composition useful for processing dielectric material, the composition comprising:
liquid carrier,
cationically-charged abrasive particles dispersed in the liquid carrier,
cyclodextrin selected from alpha-, beta-, gamma-cyclodextrin, or a combination thereof, and
alkylamine compound comprising an amine group attached to an alkyl group capable of forming a complex with the cyclodextrin in the slurry, wherein the composition has a pH below 7 and the amine group exhibits a cationic charge in the slurry.
2. The composition of claim 1 wherein the alkylamine compound has a molecular weight below 1,000 grams per mole.
3. The composition of claim 1 wherein the alkyl group has from 5 to 50 carbon atoms.
4. The composition of claim 1 wherein the amine group has a pKa of at least 5.
5. The composition of claim 1 wherein the alkylamine compound is monocationic.
6. The composition of claim 1 wherein the alkylamine has the structure:
wherein:
n is an integer,
X is N + ,
R 1 is an uncharged, straight or branched, saturated or unsaturated, alkyl group, containing from 5 to about 75 carbon atoms,
R 2 , R 3 , and R 4 can independently be selected from:
hydrogen,
an aryl or cycloalkyl group that may be substituted or unsubstituted, that may optionally include a heteroatom, and that contains fewer than 12 carbon atoms, and
a straight or branched, saturated or unsaturated alkyl group that may be substituted or unsubstituted, that may optionally include a heteroatom, and that contains fewer than 12 carbon atoms, and
wherein two or three of R 2 , R 3 , and R 4 , may form a saturated or unsaturated ring structure that may be substituted or unsubstituted, that may optionally include a heteroatom, the ring and optional substituent containing fewer than 12 carbon atoms.
7. The composition of claim 6 wherein
R 1 is an uncharged, straight or branched, saturated or unsaturated, alkyl group, containing from 5 to about 40 carbon atoms, and
each R 2 , R 3 , and R 4 is independently hydrogen or an alkyl having from 1 to 6 carbon atoms.
8. The composition of claim 6 wherein R 1 is an unbranched, saturated, uncharged alkyl group that contains from 5 to 40 carbon atoms.
9. The composition of claim 1 wherein the alkylamine is selected from: pentylamine, hexylamine, heptylamine, octylamine, nonylamine, decylamine, undecylamine, dodecylamine, N-lauroylsarcosine, and combinations thereof.
10. The composition of claim 1 comprising from about 0.001 to about 0.5 weight percent of the alkylamine based on total weight composition.
11. The composition of claim 1 comprising from about 0.01 to about 2 weight percent cyclodextrin based on total weight of the composition.
12. The composition of claim 1 comprising alkylamine-cyclodextrin complex of the cyclodextrin associated with the alkylamine compound.
13. The composition of claim 12 comprising from about 0.001 to about 2.5 weight percent of the alkylamine cyclodextrin complex.
14. The composition of claim 1 having a pH in a range from about 2 to about 5.
15. The composition of claim 1 wherein the abrasive particles are cationically charged ceria abrasive particles.
16. A method of polishing a dielectric-containing surface of a substrate, the method comprising:
providing a substrate comprising a surface that includes dielectric material,
providing a polishing pad,
providing a chemical-mechanical polishing composition comprising: aqueous medium, abrasive particles dispersed in the aqueous medium, alkylamine having an amine group and an alkyl group having at least 5 carbon atoms, and cyclodextrin, the composition having a pH below 7, and the amine group in the slurry having a cationic charge,
contacting the substrate with the polishing pad and the chemical-mechanical polishing composition; and
moving the polishing pad and the chemical-mechanical polishing composition relative to the substrate to abrade at least a portion of the dielectric layer on a surface of the substrate to polish the substrate.
17. The method of claim 16 wherein the alkylamine has the structure:
wherein:
n is an integer,
X is N + ,
R 1 is an uncharged, straight or branched, saturated or unsaturated, alkyl group, containing from 5 to about 75 carbon atoms,
R 2 , R 3 , and R 4 can independently be selected from:
hydrogen,
an aryl or cycloalkyl group that may be substituted or unsubstituted, that may optionally include a heteroatom, and that contains fewer than 12 carbon atoms, and
a straight or branched, saturated or unsaturated alkyl group that may be substituted or unsubstituted, that may optionally include a heteroatom, and that contains fewer than 12 carbon atoms, and
wherein two or three of R 2 , R 3 , and R 4 , may form a saturated or unsaturated ring structure that may be substituted or unsubstituted, that may optionally include a heteroatom, the ring and optional substituent containing fewer than 12 carbon atoms.