POLISHING PAD AND METHOD OF FABRICATING SEMICONDUCTOR DEVICE USING THE SAME
Provided is a polishing pad including a polishing layer, wherein the nuclear magnetic resonance (NMR) 13 C spectrum of a processed composition prepared by adding 1 g of the polishing layer to a 0.3 M aqueous solution of potassium hydroxide (KOH) and allowing the mixture to react in a closed container at a temperature of 150° C. for 48 hours includes a first peak appearing at 15 ppm to 18 ppm, a second peak appearing at 9 ppm to 11 ppm, and a third peak appearing at 138 ppm to 143 ppm, and the area ratio of the third peak to the second peak is about 5:1 to about 10:1. The polishing pad may exhibit physical properties corresponding to the above-described peak characteristics, thereby achieving a removal rate and defect prevention performance within desired ranges in polishing of a polishing target.
1 . A polishing pad comprising a polishing layer,
wherein a nuclear magnetic resonance (NMR) 13 C spectrum of a processed composition prepared by adding 1 g of the polishing layer to a 0.3 M aqueous solution of potassium hydroxide (KOH) and allowing the mixture to react in a closed container at a temperature of 150° C. for 48 hours includes a first peak appearing at 15 ppm to 18 ppm, a second peak appearing at 9 ppm to 11 ppm, and a third peak appearing at 138 ppm to 143 ppm, and
an area ratio of the third peak to the second peak is 5:1 to 10:1.
2 . The polishing pad of claim 1 , wherein
an area ratio of the first peak to the second peak is 10:1 to 10:5, and
an area ratio of the first peak to the third peak is 10:5 to 10:10.
3 . The polishing pad of claim 1 , wherein
the polishing layer comprises a cured product of a preliminary composition containing a urethane-based prepolymer,
a nuclear magnetic resonance (NMR) 13 C spectrum of the preliminary composition shows a fourth peak and a fifth peak in descending order of peak position (ppm) at 16 ppm to 20 ppm, and
an area ratio of the fourth peak to the fifth peak is 1:1 to 10:1.
4 . The polishing pad of claim 3 , wherein
the preliminary composition contains a reaction product of an isocyanate compound and a polyol compound,
the isocyanate compound comprises an aromatic diisocyanate compound, and
the polyol compound comprises a low-molecular-weight polyol having a weight-average molecular weight (Mw) of about 100 g/mol to less than about 300 g/mol and a high-molecular-weight polyol having a weight-average molecular weight (Mw) of about 300 g/mol to about 1,800 g/mol.
5 . The polishing pad of claim 4 , wherein
the aromatic isocyanate compound comprises 2,4-toluene diisocyanate (2,4-TDI), and
the preliminary composition contains a urethane-based prepolymer comprising at least one of a first unit structure derived from 2,4-TDI subjected to urethane reaction at one end, and a second unit structure derived from 2,4-TDI subjected to urethane reaction at both ends.
6 . The polishing pad of claim 3 , wherein the preliminary composition has an isocyanate group content of 5 wt % to I1 wt %.
7 . The polishing pad of claim 1 , wherein the polishing layer has a value of 0.1 to 0.6 as calculated according to Equation 1 below:
Mp
-
Mn
Mw
-
Mn
[
Equation
1
]
wherein Mw, Mn and Mp are the molecular weights of the processed composition, measured by gel permeation chromatography (GPC),
Mw is the weight-average molecular weight of the depolymerized composition,
Mn is the number-average molecular weight of the depolymerized composition, and
Mp is the peak molecular weight of the depolymerized composition.
8 . The polishing pad of claim 1 , wherein the processed composition has a number-average molecular weight (Mn) of 1,800 g/mol to 2,800 g/mol, a weight-average molecular weight (Mw) of 2.000 g/mol to 3,000 g/mol, and a peak molecular weight (Mp) of 2,000 g/mol to 3,000 g/mol.
9 . The polishing pad of claim 1 , wherein the processed composition has a polydispersity index (PDI, Mw/Mn) of 1 to 1.2.
10 . The polishing pad of claim 1 , wherein the polishing layer has a tensile strength of 18 N/mm 2 to 22 N/mm 2 and a hardness (Shore D) of 35 to 55.
11 . A method for producing a polishing pad, the method comprising steps of:
i) preparing a preliminary composition containing a reaction product of an isocyanate compound and a polyol compound;
ii) preparing a composition for producing a polishing layer containing the preliminary composition, a foaming agent and a curing agent; and
iii) producing a polishing layer by curing the composition for producing a polishing layer,
wherein a nuclear magnetic resonance (NMR) 13 C spectrum of a processed composition prepared by adding 1 g of the polishing layer to a 0.3 M aqueous solution of potassium hydroxide (KOH) and allowing the mixture to react in a closed container at a temperature of 150° C. for 48 hours includes a first peak appearing at 15 ppm to 18 ppm, a second peak appearing at 9 ppm to 11 ppm, and a third peak appearing at 138 ppm to 143 ppm, and
an area ratio of the third peak to the second peak is 5:1 to 10:1.
12 . The method of claim 11 , wherein an area ratio of the first peak to the second peak is 10:1 to 10:5, and an area ratio of the first peak to the third peak is 10:5 to 10:10.
13 . The method of claim 11 , wherein
a nuclear magnetic resonance (NMR) 13 C spectrum of the preliminary composition shows a fourth peak and a fifth peak in descending order of peak position (ppm) at 16 ppm to 20 ppm, and
an area ratio of the fourth peak to the fifth peak is 1:1 to 10:1.
14 . The method of claim 11 , wherein the polishing layer has a value of 0.1 to 0.6 as calculated according to Equation 1 below:
Mp
-
Mn
Mw
-
Mn
[
Equation
1
]
wherein Mw, Mn and Mp are the molecular weights of the processed composition, measured by gel permeation chromatography (GPC)
Mw is the weight-average molecular weight of the depolymerized composition,
Mn is the number-average molecular weight of the depolymerized composition, and
Mp is the peak molecular weight of the depolymerized composition.
15 . The method of claim 11 , wherein
the prepolymer composition is a urethane-based prepolymer,
the urethane-based prepolymer has an isocyanate (NCO) group content of 5 wt % to 11 wt %, and
the molar ratio of the NH 2 group of the curing agent to the isocyanate (NCO) group of the urethane-based prepolymer in the composition for producing an polishing layer in step ii) is 0.6 to 0.99.
16 . A method for fabricating a semiconductor device, the method comprising steps of:
providing a polishing pad comprising a polishing layer; and
placing a polishing target surface of a polishing target so as to be in contact with a polishing surface of the polishing layer and then polishing the polishing target while rotating relative to each other,
wherein the polishing target comprises a semiconductor substrate,
a nuclear magnetic resonance (NMR) 13 C spectrum of a processed composition prepared by adding 1 g of the polishing layer to a 0.3 M aqueous solution of potassium hydroxide (KOH) and allowing the mixture to react in a closed container at a temperature of 150° C. for 48 hours includes a first peak appearing at 15 ppm to 18 ppm, a second peak appearing at 9 ppm to 11 ppm, and a third peak appearing at 138 ppm to 143 ppm, and an area ratio of the third peak to the second peak is 5:1 to 10:1.
17 . The method of claim 16 , wherein the polishing layer has a value of 0.1 to 0.6 as calculated according to Equation 1 below:
Mp
-
Mn
Mw
-
Mn
[
Equation
1
]
wherein Mw, Mn and Mp are the molecular weights of the processed composition, measured by gel permeation chromatography (GPC),
Mw is a weight-average molecular weight of the depolymerized composition,
Mn is a number-average molecular weight of the depolymerized composition, and
Mp is a peak molecular weight of the depolymerized composition.
18 . The method of claim 16 , wherein
the semiconductor substrate comprises a silicon dioxide (SiO 2 ) layer,
the polishing target surface is a surface of the silicon dioxide (SiO 2 ) layer,
an average removal rate of the silicon dioxide layer is 1,500 Å/min to 2,500 Å/min, and
the number of surface defects on the polishing target surface after completion of the polishing is 5 or less.
19 . The method of claim 16 , wherein a rotating speed of each of the polishing target and the polishing pad is 10 rpm to 500 rpm.
20 . The method of claim 16 , further comprising a step of supplying a polishing slurry onto the polishing surface of the polishing layer, wherein the polishing slurry is supplied at a flow rate of 10 ml/min to 1.000 ml/min.