Polishing pad and preparing method of semiconductor device using the same
The present disclosure is to provide a polishing pad which is capable of providing physical properties corresponding to various polishing purposes for various polishing objects through the subdivided structural design in a thickness direction, and of securing environmental friendliness by applying a recycled or recyclable material to at least some components, in relation to disposal after use, unlike the conventional polishing pad. Specifically, it includes a polishing layer, wherein the polishing layer includes a polishing variable layer having a polishing surface; and a polishing constant layer disposed on a rear surface side of the polishing variable layer opposite to the polishing surface.
1 . A polishing pad comprising:
a polishing layer,
wherein the polishing layer includes:
a polishing variable layer having a polishing surface; and
a polishing constant layer disposed on a rear surface side of the polishing variable layer opposite to the polishing surface,
wherein the polishing constant layer includes a cured product of a first composition including a first urethane-based prepolymer, and the polishing variable layer includes a cured product of a second composition including a second urethane-based prepolymer,
wherein the first urethane-based prepolymer is a reaction product of a first alcohol component including a first polyol having a hydroxyl value (Hydroxyl number, OH-Value) of about 200 mgKOH/g to about 900 mgKOH/g, a first curing agent, and a first isocyanate component,
wherein the second urethane-based prepolymer is a reaction product of a second alcohol component including a second polyol having a hydroxyl value (Hydroxyl number, OH-Value) of 50 mgKOH/g or more and less than 200 mgKOH/g, a second curing agent, and a second isocyanate component,
wherein the first curing agent includes a compound having a hydroxyl group (—OH) as a reactive group, and the second curing agent includes a compound having an amine group (—NH2) as a reactive group, and
wherein a content of isocyanate group (—NCO) in the first composition is greater than a content of isocyanate group (—NCO) in the second composition.
2 . The polishing pad of claim 1 , wherein an interface between the polishing variable layer and the polishing constant layer is a separable interface.
3 . The polishing pad of claim 1 , wherein each of the polishing variable layer and the polishing constant layer includes at least one layer.
4 . The polishing pad of claim 1 , wherein the first polyol has a weight average molecular weight (Mw) of 100 g/mol to 1200 g/mol.
5 . The polishing pad of claim 1 , wherein the first isocyanate component is selected from the group consisting of aromatic diisocyanate, aliphatic diisocyanate, cycloaliphatic diisocyanate, and combinations thereof.
6 . The polishing pad of claim 1 , wherein the isocyanate group (—NCO) content of the first composition is 8% to 20% by weight.
7 . The polishing pad of claim 1 , wherein the first isocyanate component has an isocyanate group content (NCO %) of 30% to 65% by weight.
8 . The polishing pad of claim 1 ,
wherein the hydroxyl value (Hydroxyl number, OH-Value) of the compound having the hydroxyl group (—OH) as the reactive group is more than 600 mgKOH/g and 900 mgKOH/g or less.
9 . The polishing pad of claim 8 , wherein a molar ratio (NCO:OH) of the isocyanate group (—NCO) present as a free reactive group of the first composition and the hydroxyl group (—OH) derived from the first curing agent is 1:2 to 2:1.
10 . The polishing pad of claim 1 , wherein a content of the first curing agent of the total first composition is 15% to 30% by weight.
11 . The polishing pad of claim 1 ,
wherein a molar ratio of isocyanate groups (—NCO) of the second composition to amine groups (—NH2) of the second curing agent is 1:0.80 to 1:1.20.
12 . The polishing pad of claim 1 , wherein the content of isocyanate groups (—NCO) of the second composition is 5% to 11% by weight.
13 . The polishing pad of claim 1 , wherein the second polyol has a weight average molecular weight (Mw) of 100 g/mol to 3,000 g/mol.
14 . The polishing pad of claim 1 , wherein the polishing variable layer is of a porous structure including a plurality of pores.
15 . The polishing pad of claim 1 , wherein a compressibility of the polishing pad is 0.3% to 1.8%.
16 . A method for preparing a semiconductor device, the method comprising:
providing the polishing pad of claim 1 on a surface plate; and
polishing a polishing object while rotating the polishing pad and the polishing object relative to each other under a pressure condition after arranging a polished surface of the polishing object to be in contact with the polishing surface.
17 . The method of claim 16 , wherein a load by which the polished surface of the polishing object is pressed against the polishing surface of the polishing layer is from 0.01 psi to 20 psi.