Polymeric microgels for chemical mechanical planarization (CMP) processing

摘要

Organic-inorganic composites were prepared as colloidal particles of a cross-linked, thermally responsive polymer. Hybrid PNIPAM-polysiloxane particles and composite polymeric particles with embedded nanoparticles of an inorganic metal-oxide (MOx) such as CeO2 and TiO2 were formed. To promote the incorporation of unaggregated nanoparticles, temperature responsive microspherical gels (microgels) of N-isopropylacrylamide (NIPAM) with interpenetrating (IP) linear chains of poly(acrylic acid) (PAA) were used. The organic-inorganic composition of the hybrid polymer network was controlled by changing the time for condensation and hydrolysis of the siloxane monomer during synthesis. Experimental results indicated that the planarization of silicon oxide wafers using these hybrid particles and composites exhibited lower topographical variations and surface roughness as compared to slurries consisting of only silica or ceria nanoparticles while achieving similar removal rates and better or similar frictional characteristics.

主权项

1. A CMP polishing slurry, comprising:
a thermally-responsive polymer comprising cross-linked microspherical particles, wherein the microspherical particles further comprise a monomer, wherein the monomer is N-isopropylacrylamide;
at least one co-monomer containing an inorganic oxide functional group, wherein the inorganic oxide further comprises —MO—, where M is a metal;wherein the monomer and co-monomer are polymerized such that the inorganic oxide is integrated in the polymer network; where the microspherical particles are synthesized by the steps comprising:
adding a divinyl polymer cross-linker to water to form a reaction solution;adding N-isopropylacrylamide to the reaction solution;bubbling nitrogen through the reaction solution to displace oxygen;adding a polymerizing initiator to the reaction solution;adding the at least one co-monomer containing an inorganic oxide functional group to the reaction solution; and a CMP slurry solution.