Free radical-forming activator attached to solid and used to enhance CMP formulations
View Patent ↗A CMP composition having: a fluid comprising water and at least one oxidizing compound that produces free radicals when contacted with an activator; and a plurality of particles having a surface and comprising at least one activator selected from ions or compounds of Cu, Fe, Mn, Ti, or mixtures thereof disposed on said surface, wherein at least a portion of said surface comprises a stabilizer. Preferred activators are selected from inorganic oxygen-containing compounds of B, W, Al, and P, for example borate, tungstate, aluminate, and phosphate. The activators are preferably ions of Cu or Fe. Surprisingly, as little as 0.2 ppm and 12 ppm of activator is useful, if the activator-containing particles are suspended in the fluid as a slurry. Advantageously, certain organic acids, and especially dihydroxy enolic acids, are included in an amount less than about 4000 ppm. Advantageously, activator is coated onto abrasive particles after the particles have been coated with stabilizer.
1. A slurry composition for chemical-mechanical polishing a substrate, said slurry composition comprising:
a) a fluid comprising water and at least one oxidizing compound that produces free radicals when contacted with an activator, and wherein the fluid pH is between about 2 to about 8; and
b) a plurality of abrasive particles having a surface comprising:
i) a stabilizer selected from borate, tungstate, aluminate, phosphoric acid, pyrophosphoric acid. stannate, a silanol, and mixtures thereof, wherein if the particle is alumina then the stabilizer is not aluminate; wherein the stabilizer is bonded to said surface and
ii) at least one activator selected from ions or compounds of Ce, Cu, Fe, and mixtures thereof disposed on said surface, wherein said activator metal is present in an amount between about 0.2 ppm and 12 ppm based on the weight of the slurry.
2. The slurry composition of claim 1 wherein the activator is present in an amount between about 3 ppm and 8 ppm.
3. The slurry composition of claim 1 wherein said stabilizer forms a layer between at least a portion of said activator and said particle surface.
4. The slurry of claim 1 further comprising an α, β-dihydroxy enolic compound.
5. The slurry of claim 4 , wherein the pH of the fluid is between about 6 and about 7.
6. The slurry of claim 1 , wherein the activator is selected from Cu, Fe, and mixtures thereof.
7. The slurry of claim 6 , wherein a stabilizer is selected from borate, tungstate, aluminate, and mixtures thereof.