Customized polishing pads for CMP and methods of fabrication and use thereof
View Patent ↗The present application relates to polishing pads for chemical mechanical planarization (CMP) of substrates, and methods of fabrication and use thereof. The pads described in this invention are customized to polishing specifications where specifications include (but not limited to) to the material being polished, chip design and architecture, chip density and pattern density, equipment platform and type of slurry used. These pads can be designed with a specialized polymeric nano-structure with a long or short range order which allows for molecular level tuning achieving superior thermo-mechanical characteristics. More particularly, the pads can be designed and fabricated so that there is both uniform and nonuniform spatial distribution of chemical and physical properties within the pads. In addition, these pads can be designed to tune the coefficient of friction by surface engineering, through the addition of solid lubricants, and creating low shear integral pads having multiple layers of polymeric material which form an interface parallel to the polishing surface. The pads can also have controlled porosity, embedded abrasive, novel grooves on the polishing surface, for slurry transport, which are produced in situ, and a transparent region for endpoint detection.
1. A method of fabricating a polishing pad for polishing a substrate, the method comprising:
forming a first polymer matrix precursor in a first region of a formation mold;
forming a second polymer matrix precursor in a second region of the formation mold, the second region adjacent to the first region, wherein the first polymer matrix precursor and the second polymer matrix precursor differ by a relative amount of a curative included in the first and second polymer matrix precursors; and
co-curing the first polymer matrix precursor and the second polymer matrix precursor to form a polishing body having a first matrix region formed from the first polymer matrix precursor and having a second matrix region formed from the second polymer matrix precursor, wherein co-curing the first polymer matrix precursor and the second polymer matrix precursor comprises forming a first polyurethane material and a second polyurethane material, respectively, and wherein co-curing the first polymer matrix precursor and the second polymer matrix precursor comprises forming the first matrix region with a first compressibility and forming the second matrix region with a second compressibility different from the first compressibility, wherein co-curing the first polymer matrix precursor and the second polymer matrix precursor comprises forming a boundary between the first matrix region and the second matrix region, wherein forming the boundary comprises forming a region from a mixture of the first polymer matrix precursor and the second polymer matrix precursor, and wherein the pad is circular and an outer annulus of the circular pad is the first matrix region.
2. The method of claim 1 , wherein the curative is a polyamine.
3. The method of claim 1 , wherein the curative is a polyol.