Particulate or particle-bound chelating agents
View Patent ↗The invention generally relates to compositions and methods for chemically mechanically polishing a substrate, including a polishing accelerator, which is normally one or more oxidizers, an abrasive material, and chelating particles and/or metal-absorbent clay material. In addition, the invention can also involve methods of forming chelator particles and methods of separating metal-containing ions from polishing and/or etching solutions after polishing and/or etching.
1. A chemical mechanical polishing slurry comprising:
an oxidizer;
a diluent;
optionally an abrasive material; and
a plurality of particles that are insoluble in water wherein on the surfaces of a portion of said particles, a plurality of chelator compounds are attached through spacers that are different from the particles and the chelator compounds,
wherein the spacers are covalently bound to the surfaces of said particles;
wherein the chelator compounds contain pendant functional groups selected from the group consisting of hydroxyls, carboxylic acids, amines, amides, imines, imides, mercaptans, sulfonic acids, hydroxamic acids, carbonyl groups, esters, ethers, ureas, cyano groups, nitro groups, carbonates, inorganic salts thereof, or a combination thereof, and
wherein at least a portion of the functional groups are no further than about 7 Å from another functional group.
2. The slurry of claim 1 , wherein the particles comprise a metal oxide abrasive, iron oxide, a doped metal oxide, a metal nitride particle, a metal oxynitride particle, a metallic particle, a metal alloy particle, an organometallic particle, a polymer particle, a buckeyball, a buckeybowl, a carbon nanotube, a carbon black particle, activated carbon, a charcoal particle, a diamond particle, montmorillonite, an inorganically- and/or organically-modified clay, or a combination thereof.
3. The slurry of claim 1 , wherein the particles to which spacers with chelator compounds are attached have a net negative zeta potential before attachment.
4. The slurry of claim 3 , wherein the net negative zeta potential remains negative even after attachment of the plurality of chelator compounds.
5. The slurry of claim 1 , wherein the chelating particles to which spacers with chelator compounds are attached have an average particle size from about 1 nm to about 4000 nm.
6. The slurry of claim 1 , wherein the plurality of chelator compounds attached to the particles possess functional groups selected from the group consisting of hydroxyls, carboxylic acids, amines, amides, imines, imides, mercaptans, sulfonic acids, hydroxamic acids, carbonyl groups, esters, ethers, ureas, cyano groups, nitro groups, carbonates, inorganic salts thereof, and a combination thereof, and wherein at least a portion of the functional groups are no further than about 7 Å from another functional group.
7. The slurry of claim 1 , wherein each chelator compound, before being attached to the particle, possesses at least three functional groups selected from the group consisting of hydroxyls, carboxylic acids, amines, amides, imines, imides, mercaptans, sulfonic acids, hydroxamic acids, carbonyl groups, esters, ethers, ureas, cyano groups, nitro groups, carbonates, inorganic salts thereof, and a combination thereof.
8. The slurry of claim 1 , wherein the plurality of chelator compounds are selected from the group consisting of poly(styrene sulfonic acid), poly(vinyl sulfonic acid), poly(acrylic acid), poly(methacrylic acid), a poly(acrylate), a poly(methacrylate), a poly(alkacrylate), poly(maleic acid), poly(vinyl acetate), poly(vinyl alcohol), poly(acrylamide), poly(cyanoacrylate), a cellulosic material, and a combination or copolymer thereof.
9. The slurry of claim 1 , wherein said spacer comprises at least about 10 carbon atom linkages.
10. The slurry of claim 9 , wherein the spacer is oligomeric or (co)polymeric and is selected from the group consisting of a polysiloxane; a polyolefin; a polyacrylate; a polyalkacrylate; a polycarbonate; a perfluorinated polymer; a halogenated polymer; a polyimide; a polyimine; a conjugated (co)polymer; a polyketone; a polyether; a polyurethane; a polylactide; and a copolymer or combination thereof.
11. The slurry of claim 1 , wherein the functional groups on the chelator compounds attached to the particle comprise at least three sulfonic acid groups.
12. The slurry of claim 1 , wherein the particles to which spacers with chelator compounds are attached have an average particle size between about 10 nanometers to about 450 nanometers.
13. The slurry of claim 12 , wherein the chelator compound comprises at least one of ethylenediaminetetraacetic acid, ethylenediamine, oxalic acid, lactic acid, citric acid, and gallic acid.
14. The slurry of claim 12 , wherein the slurry further comprises a plurality of abrasive particles.
15. The slurry of claim 14 , wherein average size of the particles to which spacers with chelator compounds are attached is from about 50% to about 200% of the average size of the abrasive particles.