POLISHING PAD, PREPARATION METHOD THEREOF, AND PREPARATION METHOD OF SEMICONDUCTOR DEVICE USING SAME
Embodiments relate to a polishing pad for use in a chemical mechanical planarization (CMP) process of semiconductors, a process for preparing the same, and a process for preparing a semiconductor device using the same. According to the embodiments, it is possible to provide a polishing pad in which the average diameter of the plurality of pores contained in the polishing pad, the sphericity of the plurality of pores, and the volume ratio thereof are adjusted, thereby enhancing the polishing speed and reducing surface such defects as scratches and chatter marks appearing on the surface of a semiconductor substrate.
1 . A polishing pad, which comprises a plurality of pores, wherein the average diameter (D a ) of the plurality of pores is 5 μm to 200 μm, and the volume of pores having a sphericity of 0.2 to 0.9 according to the following Equation 1 is 50% by volume to 100% by volume based on the total volume of the plurality of pores:
Sphericity
=
π
1
3
(
6
V
pore
)
2
3
A
pore
[
Equation
1
]
in Equation 1, A pore is the cross-sectional area of pores, and V pore is the volume of pores.
2 . The polishing pad of claim 1 , wherein the plurality of pores have a sphericity of 0.001 to less than 1.0, and the polishing pad comprises one or more pores selected from first pores having a sphericity of 0.001 to less than 0.2 and second pores having a sphericity of 0.2 to less than 1.0.
3 . The polishing pad of claim 2 , wherein the total volume of the second pores is greater than the total volume of the first pores.
4 . The polishing pad of claim 2 , which does not comprise the first pores.
5 . The polishing pad of claim 1 , wherein the D a is 7 μm to 100 μm, and the volume of pores having a sphericity of 0.2 to 0.9 is 60% by volume to 100% by volume based on the total volume of the plurality of pores.
6 . The polishing pad of claim 1 , wherein the plurality of pores are derived from a solid phase foaming agent.
7 . The polishing pad of claim 6 , wherein the solid phase foaming agent is purified by a purification system.
8 . A process for preparing a polishing pad, which comprises:
mixing a urethane-based prepolymer, a solid phase foaming agent, and a curing agent to prepare a raw material mixture; and
injecting the raw material mixture into a mold and molding the raw material mixture,
wherein the polishing pad comprises a plurality of pores,
the average diameter (D a ) of the plurality of pores is 5 μm to 200 μm, and
the volume of pores having a sphericity of 0.2 to 0.9 according to the following Equation 1 is 50% by volume to 100% by volume based on the total volume of the plurality of pores:
Sphericity
=
π
1
3
(
6
V
pore
)
2
3
A
pore
[
Equation
1
]
in Equation 1, A pore is the cross-sectional area of pores, and V pore is the volume of pores.
9 . The process for preparing a polishing pad of claim 8 , wherein the solid phase foaming agent is purified by a purification system.
10 . The process for preparing a polishing pad of claim 9 , wherein the average particle diameter (D50) of the purified solid phase foaming agent is 5 μm to 200 μm.
11 . The process for preparing a polishing pad of claim 8 , wherein the mixing is carried out by a mixing system at a rotational speed of 500 rpm to 10,000 rpm.
12 . A process for preparing a semiconductor device, which comprises:
mounting a polishing pad comprising a polishing layer comprising a plurality of pores on a platen; and
relatively rotating the polishing pad and a semiconductor substrate while a polishing surface of the polishing layer and a surface of the semiconductor substrate are in contact with each other to polish the surface of the semiconductor substrate,
wherein the polishing pad comprises a plurality of pores,
the average diameter (D a ) of the plurality of pores is 5 μm to 200 μm, and
the volume of pores having a sphericity of 0.2 to 0.9 according to the following Equation 1 is 50% by volume to 100% by volume based on the total volume of the plurality of pores:
Sphericity
=
π
1
3
(
6
V
pore
)
2
3
A
pore
[
Equation
1
]
in Equation 1, A pore is the cross-sectional area of pores, and V pore , is the volume of pores.