Gradient polishing pad made from paper-making fibers for use in chemical/mechanical planarization of wafers
View Patent ↗A composite polishing pad for use in chemical-mechanical planarization (CMP) processes, which polishing pad of the invention is made of a paper-making-process produced fibrous-matrix of paper-making fibers bound with resin material, and consists of a top section with one or more lower sections, where each layer has unique material properties. Polishing performance can be substantially improved by modifying the individual characteristics of each layer. Typically, the top layer or working surface will be of a higher modulus material than the lower layers. Therefore, the sub-layers may consist of lower density regions or a modified surface structure, such as grooving, to effectively modify the bulk modulus.
1. A polishing pad having a polishing surface for use in a CMP process comprising:
a fibrous-matrix produced by a paper-making, wet laid process comprising paper-making fibers bound with resin material; said polishing surface having voids in which CMP polishing slurry flows during chemical mechanical polishing of substrates;
said fibrous-matrix comprising at least a first section defining said polishing surface, said first section having a first modulus-characteristic;
said fibrous-matrix comprising at least a second section defining a platen-attaching surface for attachment to a platen of a CMP apparatus, said second section having a second modulus-characteristic different from said first modulus-characteristic.
2. The polishing pad for use in a CMP process according to claim 1 , wherein said fibrous-matrix comprises a one-piece, single-layer, integral fibrous matrix;
said first section having said resin material therein of a first density;
said second section having said resin material therein of a second density different from said first density, whereby said first and second modulus-characteristics are provided.
3. The polishing pad for use in a CMP process according to claim 1 , wherein said first modulus-characteristic is greater than said second modulus-characteristic.
4. The polishing pad for use in a CMP process according to claim 1 , wherein said fibrous-matrix comprises a one-piece, single-layer, integral fibrous matrix;
said first section having said resin material therein of a first hardness;
said second section having said resin material therein of a second hardness different from said first hardness, whereby said first and second modulus-characteristics are provided.