Chemical mechanical polishing pad
View Patent ↗The polishing pad is suitable for planarizing at least one of semiconductor, optical and magnetic substrates. The polishing pad has an ultimate tensile strength of at least 3,000 psi (20.7 MPa) and polymeric matrix containing closed cell pores. The closed cell pores have an average diameter of 1 to 50 μm and represent 1 to 40 volume percent of the polishing pad. The pad texture has an exponential decay constant, τ, of 1 to 10 μm as a result of the natural porosity of the polymeric matrix and a surface texture developed by implementing periodic or continuous conditioning with an abrasive. The surface texture has a characteristic half height half width, W 1/2 that is less than or equal to the value of τ.
1. A conditioned polishing pad suitable for planarizing at least one of semiconductor, optical and magnetic substrates, the polishing pad having a bulk ultimate tensile strength of at least 4,000 psi (27.6 MPa), a polishing surface and a polymeric matrix, the polymeric matrix having closed cell pores, the polishing surface having opened pores, the closed cell pores having an average diameter of 1 to 50 μm, being 1 to 40 volume percent of the polishing pad at a location below the polishing surface and the polishing surface having a natural porosity distribution with an exponential decay constant, τ, of 1 to 5 μm, and a conditioner cutting characteristic texture having a half height half width, W 1/2 , less than or equal to the value of τ.
2. The polishing pad of claim 1 wherein the closed cell pores form 2 to 30 volume percent of the polymeric matrix at the location below the polishing surface.
3. The polishing pad of claim 1 wherein the polymeric matrix includes a polymer derived from difunctional or polyfunctional isocyanates and the polymeric polyurethane includes at least one selected from polyetherureas, polyisocyanurates, polyurethanes, polyureas, polyurethaneureas, copolymers thereof and mixtures thereof.
4. The polishing pad of claim 3 wherein the polymeric matrix is from the reaction product of a curative agent and an isocyanate-terminated polymer, the curative agent contains curative amines that cure the isocyanate-terminated reaction product and the isocyanate-terminated reaction product has an NH 2 to NCO stoichiometric ratio of 90 to 125 percent.
5. The polishing pad of claim 1 wherein the closed cell pores have an average diameter of 10 to 45 μm.
6. A conditioned polishing pad suitable for planarizing at least one of semiconductor, optical and magnetic substrates, the polishing pad having a bulk ultimate tensile strength of 4,000 to 14,000 psi (27.6 to 96.5 MPa), a polishing surface and a polymeric matrix, the polymeric matrix having closed cell pores, the polishing surface having opened pores, the closed cell pores having an average diameter of 1 to 50 μm, being 2 to 30 volume percent of the polishing pad at a location below the polishing surface and the polishing surface having a natural porosity distribution with an exponential decay constant, τ, of 1 to 5 μm, and a conditioner cutting characteristic texture having a half height half width, W 12 , less than or equal to the value of τ.
7. The polishing pad of claim 6 wherein the closed cell pores form 2 to 25 volume percent of the polymeric matrix at the location below the polishing surface.
8. The polishing pad of claim 6 wherein the polymeric matrix includes a polymer derived from difunctional or polyfunctional isocyanates and the polymeric polyurethane includes at least one selected from polyetherureas, polyisocyanurates, polyurethanes, polyureas, polyurethaneureas, copolymers thereof and mixtures thereof.
9. The polishing pad of claim 8 wherein the polymeric matrix is from the reaction product of a curative agent and an isocyanate-terminated polymer, the curative agent contains curative amines that cure the isocyanate-terminated reaction product and the isocyanate-terminated reaction product has an NH 2 to NCO stoichiometric ratio of 90 to 125 percent.
10. The polishing pad of claim 6 wherein the closed cell pores have an average diameter of 10 to 45 μm.