Polishing pad and method for manufacturing same
A polishing pad includes: a polishing layer having a polyurethane sheet containing substantially spherical cells, wherein E′(90%)/E′(30%) falls within a range of 0.4 to 0.7, where E′(90%) represents a storage modulus of the polyurethane sheet that has been exposed to an environment with a temperature of 23° C. and a relative humidity of 90%, as measured in a tension mode at 40° C. with an initial load of 148 g, a strain range of 0.1%, and a measurement frequency of 1.6 Hz, and E′(30%) represents a storage modulus of the polyurethane sheet that has been exposed to an environment with a temperature of 23° C. and a relative humidity of 30%, as measured in a tension mode at 40° C. with an initial load of 148 g, a strain range of 0.1%, and a measurement frequency of 1.6 Hz. Also provided is a method for manufacturing the polishing pad.
1. A polishing pad comprising:
a polishing layer having a polyurethane sheet containing substantially spherical cells, wherein
E′(90%)/E′(30%) falls within a range of 0.5 to 0.62,
where
E′(90%) represents a storage modulus of the polyurethane sheet that has been exposed to an environment with a temperature of 23° C. and a relative humidity of 90%, as measured in a tension mode at 40° C. with an initial load of 148 g, a strain range of 0.1%, and a measurement frequency of 1.6 Hz, and
E′(30%) represents a storage modulus of the polyurethane sheet that has been exposed to an environment with a temperature of 23° C. and a relative humidity of 30%, as measured in a tension mode at 40° C. with an initial load of 148 g, a strain range of 0.1%, and a measurement frequency of 1.6 Hz.
2. The polishing pad according to claim 1 , wherein
KEL(90%)/KEL(30%) falls within a range of 2 to 4,
Where
KEL means energy loss factor defined by the following equation:
KEL =tan δ×10 12 /( E ′×(1+tan δ 2 ),
wherein tan δ is E″/E′, E″ is a loss modulus and E′ is a storage modulus,
KEL(90%) represents KEL of the polyurethane sheet that has been exposed to an environment with a temperature of 23° C. and a relative humidity of 90%, as measured in a tension mode at 40° C. with an initial load of 148 g, a strain range of 0.1%, and a measurement frequency of 1.6 Hz, and
KEL(30%) represents KEL of the polyurethane sheet that has been exposed to an environment with a temperature of 23° C. and a relative humidity of 30%, as measured in a tension mode at 40° C. with an initial load of 148 g, a strain range of 0.1%, and a measurement frequency of 1.6 Hz.
3. The polishing pad according to claim 1 , wherein
E′(30%) of the polyurethane sheet is 280 to 600 MPa.
4. The polishing pad according to claim 1 , wherein
KEL(90%) of the polyurethane sheet is 450 to 1500 1/Pa,
KEL means energy loss factor defined by the following equation:
KEL =tan δ×10 12 /( E ′×(1+tan δ 2 ),
wherein tan δ is E″/E′, E″ is a loss modulus and E′ is a storage modulus,
KEL(90%) represents KEL of the polyurethane sheet that has been exposed to an environment with a temperature of 23° C. and a relative humidity of 90%, as measured in a tension mode at 40° C. with an initial load of 148 g, a strain range of 0.1%, and a measurement frequency of 1.6 Hz.
5. The polishing pad according to claim 1 , wherein
the polyurethane sheet contains hollow bodies having an average particle size 10 to 150 μm.