Polymer material, foam obtained from same, and polishing pad using those
The subject is to provide a polymer material which enables to improve planarity and planarization efficiency of a polished surface and is useful as a polishing pad which generates only a few scratches. The said subject is solved by a polymer material having a tensile modulus at 50° C. after saturation swelling with 50° C. water of 130 to 800 MPa, a loss tangent at 50° C. of not more than 0.2, and a contact angle with water of not more than 80°.
1. A polishing pad, consisting of:
a polymer material having a tensile modulus of 130 to 800 MPa at 50° C. after saturation swelling with 50° C. water, a loss tangent at 50° C. of not more than 0.2, and a contact angle with water of not more than 80°,
wherein the polymer material is a thermoplastic polyurethane obtained by reacting a polymer diol, an organic diisocyanate, and a chain extender,
wherein the thermoplastic polyurethane comprises at least 4.9 weight % but less than 6.0 weight % nitrogen atom derived from the isocyanate group, and
wherein the polymer material has substantially no foam structure.
2. The polishing pad of claim 1 , wherein the polymer material has a retention of tensile modulus of at least 55%,
wherein the retention of tensile modulus is a value obtained by dividing the tensile modulus at 50° C. after saturation swelling with 50° C. water by a tensile modulus at 50° C. after being allowed to stand at 20° C./65% RH, and then multiplying by 100.
3. The polishing pad of claim 1 , wherein a ratio, E′ 23 /E′ 50 , of a storage modulus at 23° C. (E′ 23 ) to a storage modulus at 50° C. (E′50) of the polymer material is not more than 1.8.
4. The polishing pad of claim 1 , wherein the polymer material consist essentially of the thermoplastic polyurethane having substantially no foam structure.
5. The polishing pad of claim 1 , wherein the polymer diol comprises a component having a number-average molecular weight of 1400 to 5000.
6. The polishing pad of claim 1 , wherein the polymer diol comprises at least one selected from the group consisting of a polyester diol and a polyether diol.
7. The polishing pad of claim 1 , wherein the polymer diol comprises a polyester diol comprising, in reacted form, a C 6-12 diol.
8. The polishing pad of claim 1 , wherein the polymer material is obtained by reacting:
at least one selected from the group consisting of poly(ethylene glycol), poly(tetramethylene glycol), poly(nonamethylene adipate), poly(2-methyl-1,8-octamethylene adipate), poly(2-methyl-1,8-octamethylene-co-nonamethylene adipate), and poly(methylpentane adipate) as the polymer diol;
at least one selected from the group consisting of 4,4′-diphenylmethane diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, and isophorone diisocyanate as the organic diisocyanate; and
at least one selected from the group consisting of 1,3-propanediol, 1,4-butanediol, neopentyl glycol, 1,5-pentanediol, 1,6-hexanediol, and cyclohexanedimethanol as the chain extender.
9. The polishing pad of claim 1 , wherein the polymer diol comprises a component having a number-average molecular weight of 2000 to 4000.
10. The polishing pad of claim 1 , wherein the polymer diol has a number-average molecular weight of 2000 to 4000.
11. A method of polishing a silicon wafer or semiconductor wafer, the method comprising
contacting the polishing pad of claim 1 with a surface of the silicon wafer or semiconductor wafer,
wherein the contacting is carried out by applying pressure at a prescribed velocity and for a prescribed period of time.
12. A method of producing a semiconductor device, the method comprising:
polishing a semiconductor wafer with the polishing pad of claim 1 .
13. A polishing pad, comprising:
(I) a polishing layer consisting of a polymer material having a tensile modulus of 130 to 800 MPa at 50° C. after saturation swelling with 50° C. water, a loss tangent at 50° C. of not more than 0.2, and a contact angle with water of not more than 80°; and
(II) an elastic layer having a hardness lower than that of the polishing layer,
wherein the polymer material is a thermoplastic polyurethane obtained by reacting a polymer diol, an organic diisocyanate, and a chain extender,
wherein the thermoplastic polyurethane comprises at least 4.9 weight % but less than 6.0 weight % nitrogen atom derived from the isocyanate group, and
wherein the polymer material has substantially no foam structure.
14. The polishing pad of claim 13 , wherein:
the polishing layer has a JIS-D hardness of at least 55; and
the elastic layer has a JIS-C hardness of 20 to 80.
15. The polishing pad of claim 13 , wherein:
the thickness of the polishing layer is 0.3 to 2 mm; and
the thickness of the elastic layer is 0.5 to 3 mm.
16. The polishing pad of claim 13 , wherein the elastic layer comprises a polyurethane.
17. The polishing pad of claim 13 , wherein the polymer diol comprises a component having a number-average molecular weight of 2000 to 4000.
18. The polishing pad of claim 13 , wherein the polymer diol has a number-average molecular weight of 2000 to 4000.
19. The polishing pad of claim 13 , wherein:
the polishing layer has a JIS-D hardness of 60 to 80; and
the elastic layer has a JIS-C hardness of 30 to 70.
20. The polishing pad of claim 13 , wherein:
the thickness of the polishing layer is 0.5 to 1.8 mm; and
the thickness of the elastic layer is 1.0 to 2.5 mm.