Recycled polishing pad and preparation method thereof
According to embodiments of the present invention, there are provided a recycled polishing pad and a process for preparing a recycled polishing pad. The recycled polishing pad comprises a cushion layer, an adhesive layer, and a reused polishing layer having a plurality of grooves on one side, and the compressibility of the reused polishing layer calculated by a specific equation is controlled within a predetermined range; thus, the polishing layer can be reused while excellent polishing rate and polishing uniformity are maintained.
1 . A recycled polishing pad, which comprises a cushion layer; an adhesive layer formed on the cushion layer; and a reused polishing layer attached to the adhesive layer and comprising a groove on one side,
wherein the compressibility of the reused polishing layer calculated by Equation 1 is 0.9% or more,
Compressibility
of
the
reused
polishing
layer
(
%
)
=
T
1
-
T
2
T
1
×
1
0
0
[
Equation
1
]
in Equation 1, T 1 is the thickness (mm) of the reused polishing layer measured when the reused polishing layer is pressed with a load of 85 g for 30 seconds, and
T 2 is the thickness (mm) of the reused polishing layer measured when the reused polishing layer is further pressed with a load of 885 g for 3 minutes after T 1 is measured, and
wherein the recycled polishing pad has a structure in which the cushion layer, the adhesive layer, and the reused polishing layer are sequentially laminated while in contact with each other, and
wherein the ratio of the depth of the groove to the thickness of the reused polishing layer is 0.1 to 0.7.
2 . The recycled polishing pad of claim 1 , wherein the ratio of the depth of the groove to the total thickness of the recycled polishing pad is 0.2 or less.
3 . The recycled polishing pad of claim 1 , wherein the depth of the groove is 0.10 mm to 0.75 mm.
4 . The recycled polishing pad of claim 1 , wherein the compressibility of the reused polishing layer is 0.9% to 3.0%.
5 . The recycled polishing pad of claim 1 , wherein the thickness of the reused polishing layer is thinner than the thickness of the cushion layer.
6 . The recycled polishing pad of claim 1 , wherein the compressibility of the recycled polishing pad calculated by Equation 2 is 0.25% or more,
Compressibility
of
the
recycled
polishing
pad
(
%
)
=
T
3
-
T
4
T
3
×
1
0
0
[
Equation
2
]
in Equation 2, T 3 is the thickness (mm) of the recycled polishing pad measured when the recycled polishing pad is pressed with a load of 85 g for 30 seconds, and
T 4 is the thickness (mm) of the recycled polishing pad measured when the recycled polishing pad is further pressed with a load of 885 g for 3 minutes after T 3 is measured.
7 . The recycled polishing pad of claim 1 , wherein the reused polishing layer has a hardness of 40 Shore D to 70 Shore D.
8 . The recycled polishing pad of claim 1 , wherein the recycled polishing pad has a hardness of 35 Shore D to 55 Shore D.
9 . The recycled polishing pad of claim 1 , wherein another pad layer is not interposed between the reused polishing layer and the cushion layer.
10 . A process for preparing a recycled polishing pad, which comprises:
recovering a polishing layer from a polishing pad used in a CMP process;
planarizing one side of the polishing layer;
forming a groove on one side of the planarized polishing layer to prepare a reused polishing layer; and
attaching a cushion layer to the other side of the reused polishing layer using an adhesive,
wherein the compressibility of the reused polishing layer calculated by Equation 1 is 0.9% or more,
Compressibility
of
the
reused
polishing
layer
(
%
)
=
T
1
-
T
2
T
1
×
1
0
0
[
Equation
1
]
in Equation 1, T 1 is the thickness (mm) of the reused polishing layer measured when the reused polishing layer is pressed with a load of 85 g for 30 seconds, and
T 2 is the thickness (mm) of the reused polishing layer measured when the reused polishing layer is further pressed with a load of 885 g for 3 minutes after T 1 is measured, and
wherein the recycled polishing pad has a structure in which the cushion layer, an adhesive layer, and the reused polishing layer are sequentially laminated while in contact with each other, and
wherein the ratio of the depth of the groove to the thickness of the reused polishing layer is 0.1 to 0.7.
11 . The process for preparing a recycled polishing pad according to claim 10 , wherein in the step of planarizing one side of the polishing layer, the groove of the polishing layer is removed.
12 . The process for preparing a recycled polishing pad according to claim 10 , wherein in the step of forming the groove, the groove is formed such that it has a depth of 0.7 times or less relative to the thickness of the reused polishing layer.
13 . The process for preparing a recycled polishing pad according to claim 10 , wherein the step of recovering a polishing layer comprises selecting a polishing layer having a compressibility of 0.9% or more as calculated by Equation 3 among polishing layers obtained from polishing pads used in the CMP process,
Compressibility
of
the
polishing
layer
(
%
)
=
T
5
-
T
6
T
5
×
1
0
0
[
Equation
3
]
in Equation 3, T 5 is the thickness (mm) of the polishing layer measured when the polishing layer is pressed with a load of 85 g for 30 seconds, and
T 6 is the thickness (mm) of the polishing layer measured when the polishing layer is further pressed with a load of 885 g for 3 minutes after T 5 is measured.