Formulations for chemical mechanical polishing pads and CMP pads made therewith
View Patent ↗A two component composition for making chemical mechanical polishing pad for polishing a semiconductor substrate is provided comprising a liquid aromatic isocyanate component having an unreacted isocyanate (NCO) concentration of from 15 to 40 wt. %, based on the total solids weight of the aromatic isocyanate component, such as methylene di(phenylisocyanate) (MDI), a liquid polyol component of a polyol having a polyether backbone and having from 5 to 7 hydroxyl groups per molecule, and a curative of one or more polyamine or diamine, wherein the reaction mixture comprises 50 to 65 wt. % of hard segment materials, based on the total weight of the reaction mixture. The composition when mixed cured to form a polyurethane reaction product. Also provided are CMP polishing pads made from the polyurethane reaction product by spraying the composition into a mold.
1. A polishing pad for polishing a substrate chosen from at least one of a magnetic substrate, an optical substrate and a semiconductor substrate, the polishing pad being formed from spraying a one shot formulation, the one shot formulation being a two component solvent free and substantially water free formulation comprising a liquid aromatic isocyanate component having an unreacted isocyanate (NCO) concentration of from 15 to 40 wt. %, based on the total solids weight of the aromatic isocyanate component, the isocyanate being a linear isocyanate-terminated urethane prepolymer of methylene diphenyl diisocyanate or a methylene diphenyl diisocyanate dimer, 35 to 50 wt. % of a liquid polyol component of a polyol having a polyether backbone and having from 5 to 7 hydroxyl groups per molecule and the liquid polyol forming soft segments, an isocyanate extender and a curative of one or more polyamine or diamine, wherein the reaction mixture comprises 50 to 65 wt. % of hard segment materials, based on the total weight of the reaction mixture, and, further wherein, the stoichiometric ratio of the sum of the total moles of amine (NH 2 ) groups and the total moles of hydroxyl (OH) groups in the reaction mixture to the total moles of unreacted isocyanate (NCO) groups in the reaction mixture ranges from 0.8:1.0 to 1.1:1.0 and wherein the polishing pad has a matrix and the matrix has a tensile modulus of at least 240 MPa and an elongation at break of at least 130%.
2. The polishing pad as claimed in claim 1 , wherein the liquid aromatic isocyanate component has an unreacted isocyanate (NCO) concentration of from 17.5 to 35 wt. %, based on the total solids weight of the aromatic isocyanate component.
3. The polishing pad as claimed in claim 1 , wherein the liquid aromatic isocyanate component has a hard segment weight fraction of 84 to 100 wt. %.
4. The polishing pad as claimed in claim 1 , wherein the liquid polyol component comprises a polyol having a polyether backbone and having 6 hydroxyl groups per molecule.
5. The polishing pad as claimed in claim 1 , wherein the curative is one or more aromatic diamine.
6. The polishing pad as claimed in claim 1 , wherein the liquid aromatic isocyanate component has a hard segment weight fraction of from 90 to 100 wt. %.
7. The polishing pad as claimed in claim 1 , wherein the stoichiometric ratio of the sum of the total moles of amine (NH 2 ) groups and the total moles of hydroxyl (OH) groups in the reaction mixture to the total moles of unreacted isocyanate (NCO) groups in the reaction mixture ranges from 0.85:1.0 to 1.1:1.0.
8. The polishing pad of claim 1 wherein the curative is dimethylthiotoluenediamine.