Composite pad for chemical mechanical polishing
View Patent ↗A chemical mechanical polishing pad comprising a substantially non-porous polishing layer, the polishing layer comprising a polymer matrix and agglomerates of polymer particles embedded in the polymer matrix wherein the polymer particles are present in amounts of 5 to 35 weight percent based on weight of the polishing layer, the agglomerates have a size of greater than 1 μm, the polymer particles have a tensile modulus higher than a tensile modulus of the polymer matrix. The polishing layer viscoelastic and has a GEL of greater than 1000 Pa −1 . Polishing a metal/insulator composite with such a pad can result in low amounts of dishing of the metal feature.
1. A chemical mechanical polishing pad comprising a substantially non-porous polishing layer, the polishing layer comprising a polymer matrix and agglomerates of polymer particles embedded in the polymer matrix wherein the polymer particles are present in amounts of 5 to 35 weight percent based on weight of the polishing layer, the agglomerates have a size of greater than 1 μm, the polymer particles have a tensile modulus higher than a tensile modulus of the polymer matrix, and the polishing layer is viscoelastic.
2. The chemical mechanical polishing pad of claim 1 wherein a minority portion of the agglomerates comprise an aggregate of more than one of the polymer particles and have a agglomerate size of 10 to 100 μm.
3. The chemical mechanical polishing pad of claim 1 wherein the polymer particles comprise polytetrafluoroethylene.
4. The chemical mechanical polishing pad of claim 1 wherein the polymer matrix comprises a thermoplastic polyurethane.
5. The chemical mechanical polishing pad of claim 1 wherein the energy loss factor, GEL is from 1000 to 3000 Pa −1 .
6. The chemical mechanical polishing pad of claim 1 wherein the polishing layer has a macrotexture of one or more of the following: grooves, projections.
7. The chemical mechanical polishing pad of claim 1 wherein the polishing layer has a flexural rigidity of 500 to 1500 Newtons-mm 2 , as measured by ASTM D7264/D7264M-21.
8. A method comprising polishing a composite structure of metal features surrounded by insulating material using the pad of claim 1 .
9. The method of claim 8 wherein a portion of the metal features have dimensions 5-100 μm and the polishing yields a structure having less than 100 Angstroms of dishing in the metal feature.
10. The method of claim 8 wherein polishing layer has a post-polish roughness of greater than 100 μm.