POLISHING PAD AND METHOD OF MANUFACTURING A SEMICONDUCTOR DEVICE USING THE SAME

1 . A polishing pad, which comprises a polishing layer, wherein the polishing layer comprises a urethane-based prepolymer, a foaming agent, and a curing agent, and the maximum sound absorption coefficient is 0.1 or more as measured at a frequency of 500 Hz to 4,000 Hz according to the following Equation 1:

Sound

⁢

absorption

⁢

coefficient

=

(

I

i

-

I

r

)

/

I

i

=

(

I

a

+

I

t

)

/

I

i

[

Equation

⁢

1

]

in Equation 1, when the polishing pad is cut (diameter: 45 mm) to measure sound pressure within an impedance tube according to KS F 2814-2, I i is the intensity of the incident sound, I r is the intensity of the reflected sound, I a is the intensity of the absorbed sound, and I t is the intensity of the transmitted sound.

2 . The polishing pad of claim 1 , wherein the maximum sound absorption coefficient is 0.05 or more as measured at a frequency of 1,000 Hz to 1,500 Hz, and the maximum sound absorption coefficient is 0.1 or more as measured at a frequency of 1,500 Hz to 3,000 Hz.

3 . The polishing pad of claim 1 , wherein the foaming agent comprises at least one selected from a solid phase foaming agent comprising particles having a hollow structure, a liquid phase foaming agent using a volatile liquid, and an inert gas.

4 . The polishing pad of claim 1 , wherein the foaming agent comprises a solid phase foaming agent, and the solid phase foaming agent comprises at least one selected from the group consisting of an acrylonitrile-based copolymer, a methyl methacrylate-based copolymer, a methacrylonitrile-based copolymer, and an acrylic-based copolymer.

5 . The polishing pad of claim 4 , wherein the solid phase foaming agent has an average particle size of 5 μm to 100 μm, and the content thereof is 0.1 part by weight to 5 parts by weight relative to 100 parts by weight of the urethane-based prepolymer.

6 . The polishing pad of claim 1 , wherein the curing agent comprises at least one selected from the group consisting of 4,4′-methylenebis(2-chloroaniline) (MOCA), diethyltoluenediamine (DETDA), 3,5-dimethylthio-2,6-diaminotoluene (DMTDA), 1,3-propanediol bis(4-aminobenzoate) (PDPAB), N,N′-bis(sec-butylamino)diphenylmethane, 2,6-bis(methylthio)-4-methyl-1,3-benzenediamine, 4-(4-aminobenzoyl)oxyphenyl 4-aminobenzoate, 4-(4-aminobenzoyl)oxybutyl 4-aminobenzoate, 4-[4-(4-aminobenzoyl)oxy-3-methylbutoxy]butyl 4-aminobenzoate, and methylene bis-methylanthranilate (MBNA).

7 . The polishing pad of claim 1 , wherein the content of the curing agent is 5 parts by weight to 50 parts by weight relative to 100 parts by weight of the urethane-based prepolymer.

8 . The polishing pad of claim 1 , wherein the equivalent ratio of the urethane-based prepolymer and the curing agent is 1:0.5 to 2.

9 . The polishing pad of claim 1 , wherein the urethane-based prepolymer is prepared by reacting an isocyanate compound and a polyol.

10 . The polishing pad of claim 9 , wherein the isocyanate compound comprises one selected from the group consisting of toluene 2,4-diisocyanate (2,4-TDI), toluene 2,6-diisocyanate (2,6-TDI), naphthalene 1,5-diisocyanate, para-phenylene diisocyanate, tolidine diisocyanate, 4,4′-diphenylmethane diisocyanate, hexamethylene diisocyanate, dicyclohexylmethane diisocyanate, isophorone diisocyanate, and combinations thereof.

11 . The polishing pad of claim 9 , wherein the polyol comprises one selected from the group consisting of polytetramethylene ether glycol, polypropylene ether glycol, ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,2-butanediol, 1,3-butanediol, 2-methyl-1,3-propanediol, 1,4-butanediol, neopentyl glycol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, 1,6-hexanediol, diethylene glycol, dipropylene glycol, tripropylene glycol, and combinations thereof.

12 . The polishing pad of claim 9 , wherein the polyol has a weight average molecular weight (Mw) of 100 g/mole to 3,000 g/mole.

13 . The polishing pad of claim 1 , wherein the urethane-based prepolymer has a weight average molecular weight (Mw) of 500 g/mole to 3,000 g/mole.

14 . The polishing pad of claim 1 , wherein the urethane-based prepolymer has an isocyanate end group content (NCO %) of 8% by weight to 11% by weight.

15 . The polishing pad of claim 1 , wherein the polishing layer has a hardness of 50 Shore D to 65 Shore D, a tensile strength of 15 N/mm 2 to 25 N/mm 2 , and an elongation of 90% to 130%.

16 . The polishing pad of claim 1 , wherein the polishing layer has a thickness of 0.8 mm to 5 mm and a specific gravity of 0.6 g/cm 3 to 0.9 g/cm 3 .

17 . The polishing pad of claim 1 , wherein the polishing layer comprises a plurality of pores formed from the foaming agent, the average diameter of the pores is 10 μm to 60 μm, and the total area of the pores is 30% to 60% based on the total area of the polishing layer.

18 . The polishing pad of claim 1 , wherein, when the silicon oxide layer of a silicon wafer is polished with a ceria slurry using the polishing pad, the polishing rate according to the following Mathematical Equation 1 is 2,150 Å/minute to 3,500 Å/minute:

Polishing rate (Å/minute)=difference in thickness before and after polishing (Å)/polishing time (minute).  [Mathematical Equation 1]

19 . The polishing pad of claim 1 , wherein, when the silicon oxide layer of a silicon wafer is polished with a silica slurry using the polishing pad, the average polishing rate according to the following Mathematical Equation 1 is 3,500 Å/minute to 4,500 Å/minute:

Polishing

⁢

rate

⁢

(

Å

/

minute

)

=

[

Mathematical

⁢

Equation

⁢

1

]

difference

⁢

in

⁢

thickness

⁢

before

⁢

and

⁢

after

⁢

polishing

⁢

(

Å

)

/

polishing

⁢

time

⁢

(

minute

)

.

20 . A process for preparing a semiconductor device, which comprises polishing the surface of a semiconductor substrate using the polishing pad of claim 1 .