Polishing pad, process for preparing the same, and process for preparing a semiconductor device using the 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. In the polishing pad according to the embodiment, the size (or diameter) and distribution of a plurality of pores are adjusted, whereby the polishing performance such as polishing rate and within-wafer non-uniformity can be further enhanced.
1. A polishing pad, which comprises a polishing layer comprising a plurality of pores,
wherein the total area of the pores per unit area (mm 2 ) of the polishing surface is 40% to 60%,
the D q value represented by the following Equation 1 is 5 μm to 15 μm,
the D sk value represented by the following Equation 2 is greater than 0.3 to less than 1, and
the D ku value represented by the following Equation 3 is greater than 1 to less than 5:
D
q
=
∑
i
=
1
n
d
i
2
n
[
Equation
1
]
D
sk
=
1
nD
q
3
(
∑
i
=
1
n
d
i
3
)
[
Equation
2
]
D
ku
=
1
nD
q
4
(
∑
i
=
1
n
d
i
4
)
[
Equation
3
]
in Equations 1 to 3, d is a value obtained by subtracting the number average diameter of the plurality of pores from each pore diameter, and n is the total number of pores per unit area (mm 2 ).
2. The polishing pad of claim 1 , wherein the D q value is 7 μm to 14 μm, the D sk value is greater than 0.4 to less than 1, and the D ku value is greater than 2 to less than 5.
3. The polishing pad of claim 1 , wherein n is 700 to 2,500, and d is −30 to 60.
4. The polishing pad of claim 1 , wherein, in the diameter distribution of the plurality of pores based on the polishing surface, the number average diameter of the plurality of pores is 15 μm to 25 μm, and the pore diameter at the maximum peak is 10 μm to 150 μm.
5. The polishing pad of claim 4 , wherein the pore diameter at the maximum peak is greater than the number average diameter of the plurality of pores by 5 μm to 30 μm.
6. The polishing pad of claim 1 , which has a polishing rate of 720 Å/min to 860 Å/min for a tungsten layer and a polishing rate of 2,750 Å/min to 3,300 Å/min for an oxide layer.