Polishing pad and method of manufacturing semiconductor device using the same

Abstract

To provide a polishing pad that can reduce noise and vibration in a specific frequency range.SOLUTION: A polishing pad comprises a foaming agent, the foaming agent comprising a solid-phase foaming agent, the solid-phase foaming agent comprising one or more selected from the group consisting of acrylonitrile-based copolymers, methyl methacrylate-based copolymers, methacrylonitrile-based copolymers, and acrylic-based copolymers. The polishing pad satisfies a maximum sound absorption coefficient of 0.1 or more as measured at a frequency of 500 Hz to 4,000 Hz. In addition, it can minimize energy loss caused by heat energy or vibration energy in a CMP polishing process.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present embodiment relates to a polishing pad used in a chemical mechanical polishing (CMP) process of a semiconductor element. Specifically, it relates to a polishing pad having excellent sound absorption rate characteristics and capable of minimizing energy loss due to thermal energy and vibration energy in the CMP polishing process, and a manufacturing method thereof.

Background Art

[0002] Among semiconductor manufacturing processes, chemical mechanical polishing (CMP) is a process of flattening uneven portions on the surface of a semiconductor substrate by relatively moving a platen and a head in a state where a semiconductor substrate such as a wafer is attached to a head and brought into contact with the surface of a polishing pad fixed on the platen.

[0003] In such a CMP process, since the polishing pad greatly affects the surface processing quality of the semiconductor substrate, it is required to have stable physical properties. In particular, since the polishing rate of the CMP process can vary sensitively depending on the components contained in the polishing pad and their physical properties, it is necessary to optimize the components contained in the polishing pad and their physical properties.

[0004] Also, in the CMP polishing process, polishing is performed by frictional energy, but in this case, energy loss may occur due to heat and vibration generated during the process, and performance may deteriorate, such as a decrease in the polishing rate due to such energy loss. Conventionally, in order to reduce energy loss, a method of manufacturing the polishing pad slightly softer to reduce the stiffness has been used, but there is a drawback that the flattening effect may be reduced when the stiffness is reduced. Therefore, research continues on a polishing pad and a manufacturing method thereof that can minimize energy loss and improve the polishing rate without degrading the physical properties and processability of the polishing pad.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] Therefore, the implementation example can provide a polishing pad having excellent polishing rate and a method for manufacturing a semiconductor device using the same, because the physical properties and processability of the polishing pad do not deteriorate, the sound absorption rate characteristics are excellent, and the energy loss due to thermal energy and vibration energy in the CMP polishing process can be minimized.

Means for Solving the Problems

[0007] The polishing pad according to one implementation example includes a polishing layer, and the polishing layer includes a urethane prepolymer, a foaming agent, and a curing agent, and the maximum sound absorption rate measured at a frequency of 500 Hz to 4000 Hz by the following formula 1 is 0.1 or more. [Formula 1] Sound absorption rate = (I i - I r ) / I i = (I a + I t ) / I i In the above formula 1, Based on KS F 2814-2, when the polishing pad is cut (diameter: 45 mm) and the sound pressure is measured in an impedance tube, I i is the intensity of the incident sound, I r is the intensity of the reflected sound, I a is the intensity of the absorbed sound, and I t is the intensity of the transmitted sound.

[0008] Moreover, the method for manufacturing a semiconductor device according to another implementation example includes a step of polishing the surface of a semiconductor substrate using the polishing pad.

Effects of the Invention

[0009] The polishing pad according to the implementation example can reduce noise and vibration in a specific frequency range. Specifically, since the polishing pad satisfies a maximum sound absorption rate of 0.1 or more measured at a frequency of 500 Hz to 4000 Hz according to Equation 1, it has excellent sound absorption rate characteristics and can minimize energy loss due to thermal energy and vibration energy in the CMP polishing process, so it has an excellent polishing rate.

[0010] More specifically, the polishing pad includes a urethane prepolymer, a foaming agent, and a curing agent. By controlling the types and contents of the foaming agent and the curing agent, noise and vibration in a specific frequency range can be reduced, and loss due to vibration energy can be minimized. Therefore, the efficiency with respect to frictional energy can be maximized to improve the polishing rate.

[0011] Also, the polishing pad according to the implementation example can minimize energy loss and improve the polishing rate without degrading the physical properties and processability of the polishing pad. Therefore, when manufacturing a semiconductor device using this, the CMP performance and yield can be improved.

Brief Description of the Drawings

[0012]

Figure 1

Figure 2

Modes for Carrying Out the Invention

[0013] Hereinafter, the invention will be described in detail with reference to implementation examples. The implementation examples are not limited to the content disclosed below, and can be deformed into various forms as long as the gist of the invention is not changed.

[0014] In this specification, the terms referring to each component are used to distinguish it from other components and are not intended to limit the implementation examples. Also, in this specification, singular expressions include plural expressions unless the context clearly indicates a different meaning.

[0015] In this specification, when a certain part "includes" a certain component, this means that, unless otherwise stated, it does not exclude other components but may further include other components.

[0016] In this specification, the description that one component is formed above / below another component, or is connected or coupled to each other, includes all cases where they are directly formed, connected, or coupled, or indirectly formed, connected, or coupled through other components. Also, it should be understood that the criteria regarding above / below each component can vary depending on the direction of observing the object.

[0017] All numerical ranges indicating physical property values, dimensions, etc. of the components described in this specification should be understood to be modified by the term "about" in all cases unless otherwise stated.

[0018] In the numerical ranges limiting the size, physical properties, etc. of the components described in this specification, when a numerical range limited only by the upper limit value and a numerical range limited only by the lower limit value are separately exemplified, it should be understood that the numerical range combined with these upper and lower limit values is also included in the exemplified ranges.

[0019] [Polishing Pad] The polishing pad according to one implementation example includes a polishing layer, and the polishing layer includes a urethane prepolymer, a foaming agent, and a curing agent, and has a maximum sound absorption rate of 0.1 or more when measured at a frequency of 500 Hz to 4000 Hz according to the following formula 1. [Formula 1] Sound absorption rate = (I i - I r ) / I i = (I a + I t) / I i In the above formula (1), When the polishing pad was cut (diameter: 45 mm) based on KS F 2814-2 and the sound pressure was measured in the impedance tube, I i is the intensity of the incident sound, I r is the intensity of the reflected sound, I a is the intensity of the absorbed sound, I t is the intensity of the transmitted sound.

[0020] According to one embodiment of the present invention, the highest sound absorption rate of the polishing pad measured at a frequency of 500 Hz to 4000 Hz by the above formula (1) is 0.1 or more.

[0021] Specifically, after cutting the polishing pad based on KS F 2814-2 and installing the test piece in the impedance tube, a plane sound source was generated in the tube to measure the sound pressure. At this time, the execution frequency range was 500 Hz to 4000 Hz. Using the measured sound pressure, the sound absorption rate was calculated by the above formula (1).

[0022] For example, the highest sound absorption rate of the polishing pad measured at 500 Hz to 4000 Hz, 750 Hz to 3500 Hz, 1000 Hz to 3200 Hz, 1500 Hz to 3000 Hz, 1500 Hz to 2500 Hz, 1600 Hz to 2500 Hz, or 1700 Hz to 2300 Hz based on KS F 2814-2 may be 0.11 or more, 0.12 or more, 0.15 or more, 0.16 or more, 0.18 or more, or 0.2 or more.

[0023] In addition, the polishing pad may have a maximum sound absorption rate measured at 500 Hz to 1500 Hz based on KS F 2814-2 of 0.05 or more. For example, the polishing pad may have a maximum sound absorption rate measured at 700 Hz to 1500 Hz, 800 Hz to 1500 Hz, 900 Hz to 1500 Hz, or 1000 Hz to 1500 Hz based on KS F 2814-2 of 0.06 or more, 0.07 or more, or 0.08 or more. According to one implementation example, the maximum sound absorption rate measured at a frequency of 1000 Hz to 1500 Hz is 0.05 or more, and the maximum sound absorption rate measured at a frequency of 1500 Hz to 3000 Hz is 0.1 or more.

[0024] According to one implementation example, when measuring the sound absorption rate of the polishing pad at 500 Hz to 4000 Hz based on KS F 2814-2, the polishing pad may have a sound absorption rate peak A of 0.05 or more at 500 Hz to 1500 Hz and a sound absorption rate peak B of 0.1 or more at 1600 Hz to 2500 Hz.

[0025] According to one implementation example, since the polishing pad with the maximum sound absorption rate satisfying the above range can reduce noise and vibration in a specific frequency range and minimize losses due to vibration energy, it can maximize the efficiency with respect to frictional energy and have an excellent polishing rate.

[0026] According to one implementation example, when polishing the silicon oxide layer of a silicon wafer with a ceria slurry using the polishing pad, the polishing rate according to the following Mathematical Formula 1 may be 2150 Å / min to 3500 Å / min, 2150 Å / min to 3400 Å / min, or 2200 Å / min to 3200 Å / min. [Equation 1] Polishing rate (Å / min) = Change in film thickness before and after polishing (Å) / Polishing time (min)

[0027] In addition, when polishing the silicon oxide film of a silicon wafer with a silica slurry using the polishing pad, the polishing rate according to the Mathematical Formula 1 may be 3500 Å / min to 4500 Å / min, 3600 Å / min to 4300 Å / min, or 3850 Å / min to 4200 Å / min.

[0028] <Abrasive layer> The polishing pad according to one embodiment includes an abrasive layer. Specifically, the polishing pad includes an abrasive layer containing a polyurethane resin.

[0029] The abrasive layer includes a urethane prepolymer, a foaming agent, and a curing agent. Specifically, the polyurethane resin is obtained from a composition containing a urethane prepolymer, a foaming agent, and a curing agent.

[0030] More specifically, the abrasive layer includes a polyurethane resin that is a reaction product of a urethane prepolymer, a foaming agent, and a curing agent, that is, a cured product of a composition in which the above components are mixed, thereby including a porous polyurethane resin. Further, the abrasive layer may include a large number of pores formed from the foaming agent.

[0031] The thickness of the abrasive layer is, for example, 0.8 mm or more, 1 mm or more, 1.2 mm or more, or 1.5 mm or more, and may be 5 mm or less, 3 mm or less, 2.5 mm or less, or 2 mm or less. As a specific example, the thickness of the abrasive layer may be 0.8 mm to 5 mm, or 1.5 mm to 3 mm.

[0032] The specific gravity of the abrasive layer is, for example, 0.6 g / cm 3 or more, 0.7 g / cm 3 or more, or 0.75 g / cm 3 or more, and may be 0.9 g / cm 3 or less, 0.85 g / cm 3 or less, or 0.8 g / cm 3 or less. As a specific example, the specific gravity of the abrasive layer is 0.6 g / cm 3 to 0.9 g / cm 3 or 0.7 g / cm 3 to 0.9 g / cm 3 and may be.

[0033] The hardness of the polishing layer is, for example, 30 Shore D or more, 40 Shore D or more, or 50 Shore D or more, and may be 80 Shore D or less, 70 Shore D or less, 65 Shore D or less, or 60 Shore D or less. As a specific example, the hardness of the polishing layer may be 30 Shore D to 80 Shore D or 50 Shore D to 65 Shore D.

[0034] The tensile strength of the polishing layer is, for example, 5 N / mm 2 or more, 10 N / mm 2 or more, or 15 N / mm 2 or more, and is 30 N / mm 2 or less, 25 N / mm 2 or less, or 20 N / mm 2 or less. As a specific example, the tensile strength of the polishing layer may be 5 N / mm 2 to 30 N / mm 2 or 15 N / mm 2 to 25 N / mm 2 and may be.

[0035] The elongation rate of the polishing layer is, for example, 50% or more, 70% or more, 90% or more, 106% or more, or 120% or more, and may be 300% or less, 250% or less, 200% or less, or 150% or less. As a specific example, the elongation rate of the polishing layer may be 50% to 300% or 90% to 130%. The elongation rate may be the elongation at break.

[0036] As a specific example, the polishing layer may have a hardness of 50 Shore D to 65 Shore D, a tensile strength of 15 N / mm 2 to 25 N / mm 2 and an elongation rate of 90% to 130%.

[0037] The pores are dispersed and present in the polishing layer. The average diameter of the pores is, for example, 10 μm to 60 μm, 10 μm to 50 μm, 20 μm to 50 μm, 20 μm to 40 μm, 10 μm to 30 μm, 20 μm to 25 μm, or 30 μm to 50 μm.

[0038] Further, the total area of the pores may be 30% - 60%, 35% - 50%, or 35% - 43% based on the total area of the polishing layer. Also, the total volume of the pores may be 30% - 70% or 40% - 60% based on the total volume of the polishing layer.

[0039] The polishing layer may have grooves on its surface for mechanical polishing. The grooves can have appropriate depths, widths, and intervals for mechanical polishing and are not particularly limited.

[0040] A polishing pad according to one embodiment includes a urethane prepolymer. A prepolymer generally refers to a polymer having a relatively low molecular weight in which the degree of polymerization is stopped at an intermediate stage for easy molding in manufacturing a certain final molded product. The prepolymer can be molded by itself or after reacting with other polymerizable compounds. For example, a prepolymer can be prepared by reacting an isocyanate compound and a polyol.

[0041] As the isocyanate compound used for preparing the urethane prepolymer, one selected from the group consisting of aromatic diisocyanates, aliphatic diisocyanates, alicyclic diisocyanates, and combinations thereof can be used.

[0042] The isocyanate compound may include, for example, one selected from the group consisting of toluene 2,4 - diisocyanate (2,4 - TDI), toluene 2,6 - diisocyanate (2,6 - TDI), naphthalene - 1,5 - diisocyanate, para - phenylene diisocyanate, tolidine diisocyanate, 4,4'-diphenylmethane diisocyanate, hexamethylene diisocyanate, dicyclohexylmethane diisocyanate, isophorone diisocyanate, and combinations thereof.

[0043] The polyol is a compound containing at least two or more hydroxy groups (-OH) per molecule, and may include, for example, one selected from the group consisting of polyether polyols, polyester polyols, polycarbonate polyols, polycaprolactone polyols, and combinations thereof.

[0044] The polyol may include, for example, one selected from the group consisting of polytetramethylene ether glycol, polypropylene ether glycol, ethylene glycol, 1,2 - propylene glycol, 1,3 - propylene glycol, 1,2 - butanediol, 1,3 - butanediol, 2 - methyl - 1,3 - propanediol, 1,4 - butanediol, neopentyl glycol, 1,5 - pentanediol, 3 - methyl - 1,5 - pentanediol, 1,6 - hexanediol, diethylene glycol, dipropylene glycol, tripropylene glycol, and combinations thereof.

[0045] The polyol may have a weight - average molecular weight (Mw) of 100 g / mol to 3000 g / mol. For example, the weight - average molecular weight of the polyol may be 100 g / mol to 3000 g / mol, 100 g / mol to 2000 g / mol, or 100 g / mol to 1800 g / mol.

[0046] According to one implementation example, the polyol may include a low - molecular - weight polyol with a weight - average molecular weight (Mw) of 100 g / mol to 300 g / mol and a high - molecular - weight polyol with a weight - average molecular weight (Mw) of 300 g / mol to 1800 g / mol.

[0047] Also, the urethane prepolymer may have a weight - average molecular weight of 500 g / mol to 3000 g / mol. For example, the weight - average molecular weight of the urethane prepolymer may be 500 g / mol to 2500 g / mol, 1000 g / mol to 2000 g / mol, or 1000 g / mol to 1500 g / mol.

[0048] According to one implementation example, the isocyanate compound for preparing the urethane prepolymer includes an aromatic diisocyanate compound, and the aromatic diisocyanate compound may include, for example, 2,4-toluene diisocyanate (2,4-TDI) and 2,6-toluene diisocyanate (2,6-TDI). The polyol compound for preparing the urethane prepolymer may include polytetramethylene ether glycol (PTMEG) and diethylene glycol (DEG).

[0049] According to another implementation example, the isocyanate compound for preparing the urethane prepolymer can include an aromatic diisocyanate compound and an alicyclic diisocyanate compound. For example, the aromatic diisocyanate compound includes 2,4-toluene diisocyanate (2,4-TDI) and 2,6-toluene diisocyanate (2,6-TDI), and the alicyclic diisocyanate compound may include dicyclohexylmethane diisocyanate (H12MDI). The polyol compound for preparing the urethane prepolymer may include polytetramethylene ether glycol (PTMEG) and diethylene glycol (DEG).

[0050] The isocyanate terminal group content (NCO%) of the urethane prepolymer is 5 wt% or more, 8 wt% or more, or 10 wt% or more, and may be 13 wt% or less, 12 wt% or less, or 11 wt% or less. As a specific example, the isocyanate terminal group content (NCO%) of the urethane prepolymer may be 8 wt% - 11 wt% or 9 wt% - 10 wt%.

[0051] The isocyanate terminal group content (NCO%) of the urethane prepolymer can be designed by comprehensively adjusting the types and contents of the isocyanate compound and the polyol compound for preparing the urethane prepolymer, process conditions such as the temperature, pressure, and time in the process of preparing the urethane prepolymer, and the types and contents of the additives used in the preparation of the urethane prepolymer.

[0052] When the isocyanate terminal group content (NCO%) of the urethane prepolymer satisfies the above range, the reaction rate, reaction time, final cured structure, etc. when subsequently reacting the urethane prepolymer with a curing agent can be adjusted in a direction advantageous to the polishing performance according to the use and purpose of the final polishing pad.

[0053] According to one implementation example, the isocyanate terminal group content (NCO%) of the urethane prepolymer can be 8 wt% - 11 wt% or 9 wt% - 10 wt%.

[0054] When the NCO% is less than the above range, as the electrical properties based on the chemical cured structure in the polishing pad, it may be realized that the target polishing performance cannot be achieved in terms of polishing rate and flatness, and there may be a problem that the life of the polishing pad is reduced due to an excessive increase in the cutting rate. On the other hand, when the NCO% exceeds the above range, surface defects such as scratches and chatter marks on the semiconductor substrate may increase.

[0055] The blowing agent may include one selected from the group consisting of a solid-phase blowing agent, a gas-phase blowing agent, a liquid-phase blowing agent, and combinations thereof as a component for forming the pore structure in the polishing layer.

[0056] According to one implementation example, the blowing agent is a non-chlorine-based blowing agent that does not contain a chlorine component. In particular, it does not contain a chlorine-based blowing agent component commonly used in the production of polishing pads, such as vinylidene chloride (VDC), or the use thereof can be minimized. For example, the content of the non-chlorine-based blowing agent based on the total weight of the blowing agent is 50% by weight or more, 80% by weight or more, 90% by weight or more, 95% by weight or more, 97% by weight or more, 99% by weight or more, or 99.5% by weight or more, and is also 100% by weight or less or 99.5% by weight or less. As specific examples, it can be 80% by weight to 100% by weight, 90% by weight to 100% by weight, or 80% by weight to 99.5% by weight. Also, the content of the chlorine-based blowing agent based on the total weight of the blowing agent is 20% by weight or less, 10% by weight or less, 5% by weight or less, 1% by weight or less, or 0.5% by weight or less, 0.3% by weight or less, and is also 0% by weight or more, 0.1% by weight or more, 0.5% by weight or more. As specific examples, it can be 0% by weight to 20% by weight, 0% by weight to 1% by weight, 0% by weight to 0.5% by weight, or 0.5% by weight to 20% by weight.

[0057] The blowing agent may include one or more selected from a solid-phase blowing agent containing particles with a hollow structure, a liquid-phase blowing agent using a volatile liquid, and an inert gas.

[0058] As an example, the solid-phase blowing agent may include particles with a hollow structure that expand due to heat and have their size adjusted. Such a solid-phase blowing agent has the advantage that it can be uniformly adjusted in the pore size by being put into the raw material in an already expanded form and having a uniform particle size.

[0059] Also, the solid-phase blowing agent may include expandable particles. The expandable particles are particles having the property of being expandable by heat or pressure, etc., and the size in the final polishing layer can be determined by the heat or pressure, etc., applied during the process of manufacturing the polishing layer. The expandable particles are put into the raw material in a non-pre-expanded particle state and are expanded by the heat or pressure applied during the manufacturing process of the polishing layer, and the final size can be determined.

[0060] The average particle size of the solid foaming agent is 5 μm to 100 μm, and can be, for example, 5 μm to 50 μm, 20 μm to 50 μm, 30 μm to 48 μm, or 35 μm to 45 μm. The average particle size of the solid foaming agent means, in the case of particles of the solid foaming agent being introduced into the raw material in an expanded state as described below, the average particle size of the expanded particles themselves, and in the case of particles of the solid foaming agent being introduced into the raw material in an unexpanded state as described below, can mean the average particle size of the particles after expansion by heat or pressure during the manufacturing process.

[0061] The solid foaming agent of the expandable particle type may include an outer skin of a resin material and an expansion-inducing component present inside the outer skin. Such expandable particles can be formed into a hollow structure by vaporization of the internal expansion-inducing component by heat during the manufacturing process.

[0062] For example, the outer skin may include a thermoplastic resin. The thermoplastic resin may be one or more selected from the group consisting of acrylonitrile copolymers, methacrylonitrile copolymers, and acrylic copolymers.

[0063] The thickness of the outer skin is, for example, 0.1 μm or more, 0.5 μm or more, 1 μm or more, 2 μm or more, or 3 μm or more, and is also 15 μm or less, 12 μm or less, or 10 μm or less, and can be, as a specific example, 2 μm to 15 μm.

[0064] The expansion-inducing component may include one selected from the group consisting of hydrocarbon compounds, tetraalkylsilane compounds, and combinations thereof. Specifically, the hydrocarbon compound may include one selected from the group consisting of ethane, ethylene, propane, propene, n-butane, isobutene, n-butene, isobutene, n-pentane, isopentane, neopentane, n-hexane, heptane, petroleum ether, and combinations thereof. The tetraalkylsilane compound may include one selected from the group consisting of tetramethylsilane, trimethylethylsilane, trimethylisopropylsilane, trimethyl-n-propylsilane, and combinations thereof.

[0065] The solid-phase foaming agent may include particles treated with an inorganic component. In one implementation example, the solid-phase foaming agent may be one whose surface is treated with silica (SiO 2 ) particles. The treatment of the solid-phase foaming agent with the inorganic component may prevent aggregation between multiple particles. The solid-phase foaming agent treated with the inorganic component may have different chemical, electrical, and / or physical properties on the surface of the foaming agent from those of the solid-phase foaming agent not treated with the inorganic component.

[0066] As a specific example, the foaming agent used in the polishing pad according to the implementation example includes a solid-phase foaming agent, and the solid-phase foaming agent may include one or more selected from the group consisting of acrylonitrile copolymers, methyl methacrylate copolymers, methacrylonitrile copolymers, and acrylic copolymers.

[0067] The content of the solid foaming agent is 0.1 part by weight or more, 0.5 part by weight or more, or 1 part by weight or more, based on 100 parts by weight of the urethane prepolymer, and can be 5 parts by weight or less, 3 parts by weight or less, or 2 parts by weight or less. As a specific example, the content of the solid foaming agent can be 0.1 to 5 parts by weight or 0.5 to 2 parts by weight, based on 100 parts by weight of the urethane prepolymer.

[0068] According to the intended pore structure and physical properties of the polishing layer, the type and content of the solid foaming agent can be designed.

[0069] On the other hand, the liquid foaming agent can be introduced during the process of mixing and reacting the prepolymer and the curing agent to form pores, and does not participate in the reaction between the prepolymer and the curing agent. Further, the liquid foaming agent physically vaporizes due to the heat generated during the process of mixing and reacting the prepolymer and the curing agent to form pores.

[0070] The volatile liquid foaming agent does not react with isocyanate groups, amide groups, and alcohol groups and can be in a liquid phase at 25°C. Specifically, the volatile liquid foaming agent can be selected from the group consisting of perfluorinated compounds such as cyclopentane, n-pentane, cyclohexane, n-butyl acetate, bis(nonafluorobutyl)(trifluoromethyl)amine, and perfluorotributylamine, perfluoro-N-methylmorpholine, perfluorotripentylamine, perfluorohexane. Commercially available products of the perfluorinated compounds include FC-40, FC-43, FC-70, FC-72, FC-770, FC-3283, FC-3284, etc. of 3M.

[0071] In addition, the blowing agent may include a gas-phase blowing agent. For example, the blowing agent may include a solid-phase blowing agent and a gas-phase blowing agent.

[0072] The gas-phase blowing agent may include an inert gas. The gas-phase blowing agent is introduced during the reaction process of the urethane prepolymer and the curing agent and can be used as a pore-forming element.

[0073] The type of the inert gas is not particularly limited as long as it is a gas that does not participate in the reaction between the urethane prepolymer and the curing agent. For example, the inert gas may include nitrogen gas (N 2 ), carbon dioxide gas (CO 2 ), argon gas (Ar), helium gas (He), or one selected from the group consisting of combinations thereof.

[0074] The type and content of the gas-phase blowing agent can be designed according to the target pore structure and physical properties of the polishing layer.

[0075] The inert gas can be introduced in a volume corresponding to 10% to 30% of the total volume of the composition. Specifically, the inert gas can be introduced in a volume corresponding to 15% to 30% of the total volume of the composition. Specifically, the gas-phase blowing agent can be injected through a predetermined injection line during the mixing process of the urethane prepolymer, the solid-phase blowing agent, and the curing agent. For example, the injection rate of the gas-phase blowing agent can be about 0.8 L / min to about 2.0 L / min, about 0.8 L / min to about 1.8 L / min, about 0.8 L / min to about 1.7 L / min, about 1.0 L / min to about 2.0 L / min, about 1.0 L / min to about 1.8 L / min, or about 1.0 L / min to about 1.7 L / min.

[0076] The curing agent is a compound that chemically reacts with the urethane prepolymer to form the final cured structure in the polishing layer and may include, for example, an amine compound or an alcohol compound. Specifically, the curing agent may include one selected from the group consisting of aromatic amines, aliphatic amines, aromatic alcohols, aliphatic alcohols, and combinations thereof.

[0077] According to one implementation example, the curing agent may include a non-chlorine-based curing agent that does not contain a chlorine component. For example, the content of the non-chlorine-based curing agent based on the total weight of the curing agent is 50% by weight or more, 80% by weight or more, 90% by weight or more, 95% by weight or more, 97% by weight or more, 99% by weight or more, or 99.5% by weight or more, and is also 100% by weight or less or 99.5% by weight or less. As specific examples, it may be 80% by weight to 100% by weight, 90% by weight to 100% by weight, or 80% by weight to 99.5% by weight. Also, the content of the chlorine-based curing agent based on the total weight of the curing agent is 20% by weight or less, 10% by weight or less, 5% by weight or less, 1% by weight or less, or 0.5% by weight or less, 0.3% by weight or less, and is also 0% by weight or more, 0.1% by weight or more, 0.5% by weight or more. As specific examples, it may be 0% by weight to 20% by weight, 0% by weight to 1% by weight, 0% by weight to 0.5% by weight, or 0.5% by weight to 20% by weight.

[0078] The curing agent may be at least one selected from a solid-phase curing agent and a liquid-phase curing agent.

[0079] The solid-phase curing agent may contain an active hydrogen group. The solid-phase curing agent may contain an amine group (-NH 2 ) as the active hydrogen group.

[0080] Also, the solid-phase curing agent may be an ester compound having two or more benzene rings. Specifically, the solid-phase curing agent may contain two or more of the ester groups in the molecule.

[0081] The solid-phase curing agent may have a weight average molecular weight of, for example, 150 g / mol to 400 g / mol, 150 g / mol to 350 g / mol, 200 g / mol to 350 g / mol, 250 g / mol to 350 g / mol, 300 g / mol to 350 g / mol. Also, the solid-phase curing agent may have a melting point (m.p) of 100°C to 150°C, 100°C to 140°C, 110°C to 130°C.

[0082] In one implementation example, the solid-phase curing agent may include one or more selected from the group consisting of 1,3-propanediol bis(4-aminobenzoate) (PDPAB), 4-(4-aminobenzoyl)oxyphenyl 4-aminobenzoate, 4-(4-aminobenzoyl)oxybutyl 4-aminobenzoate, 4-[4-(4-aminobenzoyl)oxy-3-methylbutoxy]butyl 4-aminobenzoate, and methylene bis-methyl anthranilate (MBNA).

[0083] The liquid-phase curing agent may contain an active hydrogen group. As the active hydrogen group, the liquid-phase curing agent includes one or more selected from the group consisting of an amine group (-NH 2 ), a hydroxyl group (-OH), a carboxylic acid group (-COOH), an epoxy group, and combinations thereof. Specifically, it may contain an amine group (-NH 2 ).

[0084] Also, the liquid-phase curing agent may contain sulfur in the molecule, specifically, it may contain two or more sulfur elements in the molecule.

[0085] The liquid-phase curing agent has a weight average molecular weight of 50 g / mol to 300 g / mol, for example, 100 g / mol to 250 g / mol, for example, 150 g / mol to 250 g / mol, for example, 200 g / mol to 250 g / mol.

[0086] Also, the liquid-phase curing agent may be in a liquid phase at room temperature. Or, the liquid-phase curing agent may have a boiling point (b.p) of 160°C to 240°C, specifically 170°C to 240°C, more specifically 170°C to 220°C.

[0087] Examples of the liquid-phase curing agent may include one or more selected from the group consisting of 3,5-dimethylthio-2,6-diaminotoluene (DMTDA), 2,6-bis(methylthio)-4-methyl-1,3-benzenediamine, and N,N'-bis(sec-butylamino)diphenylmethane.

[0088] In addition, the hardener may further include other hardeners in addition to the liquid-phase hardener and the solid-phase hardener. The other hardeners may be, for example, one or more of an amine compound and an alcohol compound. Specifically, the other hardeners may include one or more compounds selected from the group consisting of aromatic amines, aliphatic amines, aromatic alcohols, and aliphatic alcohols.

[0089] For example, the other hardeners may be one or more selected from the group consisting of diaminodiphenyl methane, diaminodiphenyl sulphone, m-xylylene diamine, isophoronediamine, ethylenediamine, diethylenetriamine, triethylenetetramine, polypropylenediamine, polypropylenetriamine, ethylene glycol, diethyleneglycol, dipropyleneglycol, butanediol, hexanediol, glycerine, and trimethylolpropane.

[0090] As a specific example, the curing agent may include one or more selected from the group consisting of 4,4'-methylenebis(2-chloroaniline) (MOCA), diethyltoluenediamine (DETDA), 3,5-dimethylthio-2,6-diaminotoluene (DMTDA), 1,3-propanediol bis(4-aminobenzoate) (PDPAB), N,N'-bis(sec-butylamino)diphenylmethane, 2,6-bis(methylthio)-4-methyl-1,3-benzenediamine, 4-(4-aminobenzoyl)oxyphenyl 4-aminobenzoate, 4-(4-aminobenzoyl)oxybutyl 4-aminobenzoate, 4-[4-(4-aminobenzoyl)oxy-3-methylbutoxy]butyl 4-aminobenzoate, and methylene bis-methyl anthranilate (MBNA).

[0091] The content of the curing agent is 5 parts by weight or more, 10 parts by weight or more, 15 parts by weight or more, or 20 parts by weight or more based on 100 parts by weight of the urethane prepolymer, and may be 50 parts by weight or less, 45 parts by weight or less, 40 parts by weight or less, 35 parts by weight or less, 30 parts by weight or less, or 25 parts by weight or less. Specifically, the content of the curing agent is 10 to 40 parts by weight based on 100 parts by weight of the urethane prepolymer, and more specifically, it may be 15 to 35 parts by weight or 15 to 25 parts by weight.

[0092] Also, the equivalent ratio of the urethane prepolymer to the curing agent may be 1:0.5 to 2. For example, the equivalent ratio of the urethane prepolymer to the curing agent may be 1:0.5 to 1.8, 1:0.5 to 1.5, 1:0.5 to 1.0, 1:0.6 to 1.2, 1:0.8 to 1.2, or 1:0.8 to 1.0.

[0093] By satisfying the above range for the equivalent ratio of the urethane prepolymer to the curing agent, noise and vibration in a specific frequency range can be reduced, and loss due to vibration energy can be minimized, so that the efficiency with respect to frictional energy can be maximized and the polishing rate can be improved.

[0094] The composition for manufacturing the polishing layer may further contain other additives such as surfactants and reaction rate regulators. The names such as "surfactant" and "reaction rate regulator" are arbitrarily named based on the main role of the substance, and each corresponding substance does not necessarily perform only the functions limited by the name.

[0095] The surfactant is not particularly limited as long as it plays a role in preventing phenomena such as aggregation or overlap of pores. For example, the surfactant may include a silicone-based surfactant.

[0096] The surfactant can be used in a content of 0.2 parts by weight to 2 parts by weight based on 100 parts by weight of the urethane prepolymer. Specifically, the surfactant can be included in a content of 0.2 parts by weight to 1.9 parts by weight, 0.2 parts by weight to 1.8 parts by weight, 0.2 parts by weight to 1.7 parts by weight, 0.2 parts by weight to 1.6 parts by weight, 0.2 parts by weight to 1.5 parts by weight, or 0.5 parts by weight to 1.5 parts by weight based on 100 parts by weight of the urethane prepolymer. When the surfactant is included in the content within the above range, pores derived from the gas-phase foaming agent can be stably formed and maintained in the mold.

[0097] The reaction rate regulator plays a role in promoting or delaying the reaction, and a reaction accelerator, a reaction retarder, or both can be used according to the purpose. The reaction rate regulator may include a reaction accelerator. For example, the reaction accelerator may be one or more reaction accelerators selected from the group consisting of tertiary amine-based compounds and organometallic-based compounds.

[0098] Specifically, the reaction rate regulator may include one or more selected from the group consisting of triethylenediamine, dimethylethanolamine, tetramethylbutanediamine, 2-methyl-triethylenediamine, dimethylcyclohexylamine, triethylamine, triisopropanolamine, 1,4-diazabicyclo(2,2,2)octane, bis(2-methylaminoethyl)ether, trimethylaminoethylethanolamine, N,N,N,N,N''-pentamethyldiethylenetriamine, dimethylaminoethylamine, dimethylaminopropylamine, benzyldimethylamine, N-ethylmorpholine, N,N-dimethylaminoethylmorpholine, N,N-dimethylcyclohexylamine, 2-methyl-2-azanorborene, dibutyltin dilaurate, stannous octoate, dibutyltin diacetate, dioctyltin diacetate, dibutyltin maleate, dibutyltin di-2-ethylhexanoate, and dibutyltin dimercaptide. Specifically, the reaction rate regulator may include one or more selected from the group consisting of benzyldimethylamine, N,N-dimethylcyclohexylamine, and triethylamine.

[0099] The reaction rate regulator may be used in an amount of 0.05 parts by weight to 2 parts by weight based on 100 parts by weight of the urethane prepolymer. Specifically, the reaction rate regulator may be used in an amount of 0.05 parts by weight to 1.8 parts by weight, 0.05 parts by weight to 1.7 parts by weight, 0.05 parts by weight to 1.6 parts by weight, 0.1 parts by weight to 1.5 parts by weight, 0.1 parts by weight to 0.3 parts by weight, 0.2 parts by weight to 1.8 parts by weight, 0.2 parts by weight to 1.7 parts by weight, 0.2 parts by weight to 1.6 parts by weight, 0.2 parts by weight to 1.5 parts by weight, or 0.5 parts by weight to 1 part by weight based on 100 parts by weight of the urethane prepolymer. When the reaction rate regulator is used within the above content range, the curing reaction rate of the prepolymer composition can be appropriately adjusted to form a polishing layer having pores and hardness of a desired size.

[0100] <Support layer> According to an embodiment of the present invention, the polishing pad may include a support layer.

[0101] The support layer forms a lower pad, and while supporting the polishing layer, it plays a role of absorbing and dispersing external impacts applied to the polishing layer, thereby minimizing the occurrence of damage and defects to the object to be polished during the polishing process using the polishing pad.

[0102] The support layer may include, but is not limited to, a non-woven fabric or suede. In one implementation example, the support layer may be a resin-impregnated non-woven fabric. The non-woven fabric may be a fiber non-woven fabric including one or more selected from the group consisting of polyester fibers, polyamide fibers, polypropylene fibers, and polyethylene fibers.

[0103] The resin impregnated in the non-woven fabric may include one or more selected from the group consisting of polyurethane resin, polybutadiene resin, styrene-butadiene copolymer resin, styrene-butadiene-styrene copolymer resin, acrylonitrile-butadiene copolymer resin, styrene-ethylene-butadiene-styrene copolymer resin, silicone rubber resin, polyester-based elastomer resin, and polyamide-based elastomer resin.

[0104] The thickness of the support layer is, for example, 0.3 mm or more or 0.5 mm or more, and may also be 3 mm or less, 2 mm or less, or 1 mm or less. As a specific example, the thickness of the support layer may be 0.3 mm to 3 mm or 0.5 mm to 1 mm.

[0105] The hardness of the support layer is, for example, 50 Asker C or more, 60 Asker C or more, or 70 Asker C or more, and may also be 100 Asker C or less, 90 Asker C or less, or 80 Asker C or less. As a specific example, the hardness of the support layer may be 50 Asker C to 100 Asker C or 60 Asker C to 90 Asker C.

[0106] Also, an adhesive layer may be inserted between the polishing layer (upper pad) and the support layer (lower pad).

[0107] The adhesive layer may contain a hot melt adhesive. The hot melt adhesive may contain one or more selected from the group consisting of polyurethane resins, polyester resins, ethylene-vinyl acetate resins, polyamide resins, and polyolefin resins. Specifically, the hot melt adhesive may be one or more selected from the group consisting of polyurethane resins and polyester resins.

[0108] Also, a double-sided tape is attached to the lower part of the support layer, and when applied to a CMP apparatus, the release paper of the double-sided tape can be removed and attached to the platen for use.

[0109] [Method for manufacturing a polishing pad] A method for manufacturing a polishing pad according to one implementation example includes a step of preparing a polishing pad composition containing a urethane prepolymer, a foaming agent, and a curing agent, a step of injecting the polishing pad composition into a mold and curing it to manufacture a polishing layer, and a step of bonding the polishing layer to a support layer.

[0110] The specific types and contents of the urethane prepolymer, curing agent, and foaming agent are as exemplified above.

[0111] As a specific example, the foaming agent includes a solid-phase foaming agent, and the solid-phase foaming agent includes one or more selected from the group consisting of acrylonitrile copolymers, methyl methacrylate copolymers, methacrylonitrile copolymers, and acrylic copolymers. The curing agent may include one or more selected from the group consisting of diethyltoluenediamine (DETDA), 3,5-dimethylthio-2,6-diaminotoluene (DMTDA), 1,3-propanediol bis(4-aminobenzoate) (PDPAB), N,N'-bis(sec-butylamino)diphenylmethane, 2,6-bis(methylthio)-4-methyl-1,3-benzenediamine, 4-(4-aminobenzoyl)oxy phenyl 4-aminobenzoate, 4-(4-aminobenzoyl)oxybutyl 4-aminobenzoate, 4-[4-(4-aminobenzoyl)oxy-3-methylbutoxy]butyl 4-aminobenzoate, and methylene bis-methyl anthranilate (MBNA).

[0112] The polishing pad composition can be prepared by sequentially or simultaneously mixing a urethane prepolymer, a foaming agent, and a curing agent.

[0113] As an example, the step of preparing the polishing pad composition can be performed by further mixing the foaming agent after mixing the urethane prepolymer with the curing agent, or by further mixing the curing agent after mixing the urethane prepolymer with the foaming agent.

[0114] As another example, the urethane prepolymer, the curing agent, and the foaming agent may be introduced into the mixing process substantially simultaneously. When a foaming agent, a surfactant, and an inert gas are further added, they may also be introduced into the mixing process substantially simultaneously.

[0115] As still another example, the urethane prepolymer, the foaming agent, and the surfactant may be premixed, and then the curing agent may be added, or the curing agent and the inert gas may be added together.

[0116] In the mixing, a urethane prepolymer and a curing agent are mixed to initiate a reaction, and a foaming agent and an inert gas can be uniformly dispersed in the raw materials. At this time, the reaction rate regulator can intervene in the reaction between the urethane prepolymer and the curing agent from the initial stage of the reaction to adjust the reaction rate. Specifically, the mixing can be performed at a speed of 1000 rpm to 10000 rpm or 4000 rpm to 7000 rpm. When within the above speed range, it may be more advantageous for the inert gas and the foaming agent to be uniformly dispersed in the raw materials.

[0117] Also, the step of preparing the polishing pad composition is carried out under the conditions of 50°C to 150°C and can be carried out under vacuum degassing conditions as required.

[0118] When the foaming agent contains a solid-phase foaming agent, the step of preparing the polishing pad composition may include a step of mixing the urethane prepolymer and the solid-phase foaming agent to prepare a first preliminary composition, and a step of mixing the first preliminary composition and a curing agent to prepare a second preliminary composition.

[0119] The viscosity of the first preliminary composition can be about 1000 cps to about 2000 cps, about 1000 cps to about 1800 cps, about 1000 cps to about 1600 cps, or about 1000 cps to about 1500 cps at about 80°C.

[0120] When the foaming agent contains a gas-phase foaming agent, the step of preparing the polishing pad composition may include a step of preparing a third preliminary composition containing the urethane prepolymer and the curing agent, and a step of injecting the gas-phase foaming agent into the third preliminary composition to prepare a fourth preliminary composition. In one implementation example, the third preliminary composition may further contain a solid-phase foaming agent.

[0121] According to one implementation example, the step of manufacturing the polishing layer may include a step of preparing a mold preheated to a first temperature, a step of injecting the polishing pad composition into the preheated mold and curing it, and a step of post-curing the cured polishing pad composition under a second temperature condition higher than the preheating temperature.

[0122] According to one implementation example, the temperature difference between the first temperature and the second temperature is from about 10°C to about 40°C, and can be, for example, from about 10°C to about 35°C or from about 15°C to about 35°C. As a specific example, the first temperature can be from about 60°C to about 100°C, from about 65°C to about 95°C, or from about 70°C to about 90°C. As a specific example, the second temperature is from about 100°C to about 130°C, and can be, for example, from about 100°C to about 125°C or from about 100°C to about 120°C.

[0123] The step of curing the polishing pad composition at the first temperature can be carried out for about 5 minutes to about 60 minutes, about 5 minutes to about 40 minutes, about 5 minutes to about 30 minutes, or about 5 minutes to about 25 minutes.

[0124] The step of post-curing the polishing pad composition cured at the first temperature at the second temperature can be carried out for about 5 hours to about 30 hours, about 5 hours to about 25 hours, about 10 hours to about 30 hours, about 10 hours to about 25 hours, about 12 hours to about 24 hours, or about 15 hours to about 24 hours.

[0125] Then, the step of injecting the polishing pad composition into the mold and then curing it can be carried out under temperature conditions of 60°C to 120°C and pressure conditions of 50 kg / m 2 ~200 kg / m 2 of pressure conditions.

[0126] In addition, the manufacturing method may further include a step of cutting the surface of the obtained polishing pad, a step of processing grooves on the surface, an adhesion step with the lower layer, an inspection step, a packaging step, etc. These steps can be carried out by a normal polishing pad manufacturing method.

[0127] As an example, the manufacturing method of the polishing pad may include a step of processing at least one surface of the polishing layer. The step of processing at least one surface of the polishing layer may include at least one of a step of forming grooves on at least one surface of the polishing layer, a step of turning at least one surface of the polishing layer, and a step of roughening at least one surface of the polishing layer.

[0128] The groove(s) may include at least one of a concentric groove formed at a predetermined interval from the center of the polishing layer and a radial groove continuously connected from the center of the polishing layer to the edge of the polishing layer. The turning may be performed by a method of shaving off a predetermined thickness of the polishing layer using a cutting tool. The roughening may be performed by a method of processing the surface of the polishing layer with a sanding roller.

[0129] [Method for manufacturing a semiconductor device] Moreover, a method for manufacturing a semiconductor device according to another embodiment includes a step of polishing the surface of a semiconductor substrate using the polishing pad.

[0130] Specifically, the method for manufacturing a semiconductor device may include a step of providing the polishing pad according to the embodiment, and a step of relatively rotating the polishing surface of the polishing layer and the surface of the semiconductor substrate so as to be in contact with each other, and polishing the surface of the semiconductor substrate.

[0131] FIG. 2 shows a semiconductor device manufacturing process using a polishing pad according to an embodiment. Referring to FIG. 2, after mounting a polishing pad 100 according to the embodiment on a platen 200, a semiconductor substrate 600 to be polished is disposed on the polishing pad 100. At this time, the surface to be polished of the semiconductor substrate 600 is in direct contact with the polishing surface of the polishing pad 100. For polishing, a polishing slurry 400 may be sprayed onto the polishing pad via a nozzle. The flow rate of the polishing slurry 400 supplied via the nozzle is selected according to the purpose within the range of about 10 cm 3 / min to about 1000 cm 3 / min, and for example, may be about 50 cm 3 / min to about 500 cm 3 / min, but is not limited thereto.

[0132] Thereafter, the semiconductor substrate 600 and the polishing pad 100 rotate relative to each other, and the surface of the semiconductor substrate 600 can be polished. At this time, the rotation direction of the semiconductor substrate 600 and the rotation direction of the polishing pad 100 may be the same direction or the opposite direction. The rotation speeds of the semiconductor substrate 600 and the polishing pad 100 are each selected according to the purpose within the range of about 10 rpm to about 500 rpm, and for example, may be about 30 rpm to about 200 rpm, but are not limited thereto.

[0133] The semiconductor substrate 600 can have its surface polished after being pressed and brought into contact with the polishing surface of the polishing pad 100 with a predetermined load while being mounted on the polishing head 510. The load applied to the surface of the semiconductor substrate 600 and the polishing surface of the polishing pad 100 by the polishing head 510 is about 1 gf / cm 2 to about 1000 gf / cm 2 and is selected according to the purpose within the range, and for example, may be about 10 gf / cm 2 to about 800 gf / cm 2 but is not limited thereto.

[0134] In one implementation example, the semiconductor substrate 600 to be polished may include an oxide film, a tungsten film, or a composite film thereof. Specifically, the semiconductor substrate 600 may include an oxide film, a tungsten film, or a composite film of an oxide film and a tungsten film. The composite film of the oxide film and the tungsten film may be a multilayer film in which the tungsten film is laminated on one surface of the oxide film, or may be a single-layer film in which an oxide region and a tungsten region are mixed within one layer. When the object to be polished has such film quality characteristics and at the same time the polishing pad has the characteristics according to the implementation example, the semiconductor element manufactured by the manufacturing method of the semiconductor element can minimize defects.

[0135] In one implementation example, the method for manufacturing the semiconductor device may further include, in the step of polishing the object to be polished, a step of supplying any one of the slurry for polishing the oxide film and the slurry for polishing the tungsten film, or a step of sequentially supplying the slurry for polishing the oxide film and the slurry for polishing the tungsten film to the polishing surface.

[0136] For example, when the semiconductor substrate as the object to be polished includes an oxide film, the method for manufacturing the semiconductor device may include a step of supplying the slurry for polishing the oxide film. When the semiconductor substrate includes a tungsten film, the method for manufacturing the semiconductor device may include a step of supplying the slurry for polishing the tungsten film. When the semiconductor substrate includes a composite film of an oxide film and a tungsten film, the method for manufacturing the semiconductor device may include a step of sequentially supplying the slurry for polishing the oxide film and the slurry for polishing the tungsten film to the polishing surface. At this time, depending on the process, the slurry for polishing the oxide film may be supplied first and then the slurry for polishing the tungsten film may be supplied later, or the slurry for polishing the tungsten film may be supplied first and then the slurry for polishing the oxide film may be supplied later.

[0137] In one implementation example, the method for manufacturing the semiconductor device may further include, in order to maintain the polishing surface of the polishing pad 100 in a state suitable for polishing, a step of processing the polishing surface of the polishing pad 100 by a conditioner 470 simultaneously with the polishing of the semiconductor substrate 600.

[0138] By adjusting the chlorine content of the polishing layer of the polishing pad according to the one implementation example within a specific range, while maintaining excellent physical properties and performance of the polishing pad, the size of debris can be reduced to minimize the occurrence of defects and scratches during the CMP process. Therefore, a semiconductor device of excellent quality can be efficiently manufactured using the polishing pad.

[0139] (Example) The above content will be further described in detail by the following examples. However, the following examples are only for illustrating the present invention, and the scope of the examples is not limited to these only.

[0140] [Manufacture of polishing pad] (Example 1) (1) Preparation of urethane prepolymer Toluene diisocyanate (TDI), dicyclohexylmethane diisocyanate (H12MDI), polytetramethylene ether glycol (PTMEG), and diethylene glycol (DEG) were charged into a four-necked flask and reacted at 80 °C for 3 hours to prepare a urethane prepolymer with a terminal NCO group content (NCO%) of 10% by weight.

[0141] (2) Manufacture of polishing pad A casting device equipped with tanks and input lines for supplying raw materials such as urethane prepolymer, curing agent, inert gas, and foaming agent was prepared. The urethane prepolymer prepared above, curing agent (4,4'-methylenebis(2-chloroaniline), MOCA), solid-phase foaming agent (acrylonitrile / dichloroethane, expanded cell type, average particle size: 40 μm to 42 μm), inert gas (N 2 )), and silicone surfactant (Evonik) were filled into their respective tanks. At this time, 1.5 parts by weight of the solid-phase foaming agent was added to 100 parts by weight of the urethane prepolymer, and the urethane prepolymer and the curing agent were added in an equivalent ratio of 1:1 and a total amount of 10 kg / min.

[0142] Thereafter, the raw materials were stirred while being fed into the mixing head at a constant speed through their respective input lines (rotation speed of the mixing head: about 5000 rpm). A mold (1000 mm × 1000 mm × 3 mm) was prepared and preheated at 80 °C, and the stirred mixture was discharged into the mold and reacted to obtain a solidified cake-shaped molded body. Thereafter, the upper and lower ends of the molded body were cut to obtain a polishing layer for the top pad.

[0143] Thereafter, through a surface milling process and a groove forming process on the polishing layer, a polishing pad was manufactured by bonding it to a support layer for a lower pad (sub pad) with a hot melt adhesive. At this time, a double-sided tape (model name: 442JS, 3M) was bonded to the lower part of the support layer so that it could adhere to the platen of the CMP apparatus.

[0144] (Example 2) A polishing pad was manufactured in the same manner as in Example 1, except that a solid-phase foaming agent (acrylonitrile / methacrylonitrile copolymer, expanded cell type, average particle size: 40 μm to 42 μm) was used in step (2).

[0145] (Example 3) A polishing pad was manufactured in the same manner as in Example 1, except that the equivalent ratio of the urethane prepolymer to the curing agent was 1:0.8 in step (2).

[0146] (Comparative Example 1) A commercially available polishing pad (model name: IK4140, DUPONT) was used as Comparative Example 1.

[0147] (Comparative Example 2) A commercially available polishing pad (model name: IC1010, DUPONT) was used as Comparative Example 2.

[0148] (Experimental Example 1: Sound absorption rate and attenuation ratio) For the polishing pads of Examples 1 to 3, Comparative Example 1, and Comparative Example 2, the sound absorption rate and attenuation ratio were measured based on KS F 2814-2.

[0149] Specifically, based on KS F 2814-2, after cutting the polishing pad and installing the test piece in an impedance tube, a plane sound wave source was generated in the tube to measure the sound pressure, and then the maximum sound absorption rate was calculated by the following formula 1. At this time, the execution frequency range was 500 Hz to 4000 Hz. [Formula 1] Sound absorption rate = (I i -Ir ) / I i =(I a +I t ) / I i In the above formula (1), when the polishing pad was cut (diameter: 45 mm) based on KS F 2814-2 and the sound pressure was measured in the impedance tube, I i is the intensity of the incident sound, I r is the intensity of the reflected sound, I a is the intensity of the absorbed sound, I t is the intensity of the transmitted sound.

[0150] (Experimental Example 2: Removal Rate) Regarding the polishing pads of the above Examples 1 to 3, Comparative Example 1, and Comparative Example 2, the polishing pad was fixed on the platen of the CMP apparatus, and the silicon oxide film of the silicon wafer (diameter: 300 mm) was set below, and the CMP process was performed to measure the removal rate.

[0151] Specifically, the polishing load was adjusted to 4.0 psi, and while the calcined ceria slurry / silica slurry was introduced onto the polishing pad at a rate of 250 mL / min, the platen was rotated at 150 rpm for 60 seconds to polish the silicon oxide film. After polishing, the silicon wafer was removed from the carrier, attached to a spin dryer, washed with purified water, and then dried with nitrogen for 15 seconds. The thickness difference of the silicon oxide film before and after polishing of the dried silicon wafer was measured using a spectroscopic interference thickness measuring instrument (SI-F80R, manufactured by Kyence), and the removal rate was calculated by the following mathematical formula (1). [Equation 1] Removal rate (Å / min) = Film thickness change before and after polishing (Å) / Polishing time (min)

[0152] (Experimental Example 3: Defects) Regarding the polishing pads of the above Examples 1 to 3, Comparative Example 1, and Comparative Example 2, the change in defects before and after polishing was measured.

[0153] Specifically, polishing was performed in the same manner as in Experimental Example 2 using a CMP polishing apparatus. After polishing, the silicon wafer was transferred to a cleaner and washed with 1% HF, deionized water (DIW), and 1% H 2 NO 3 NO for 10 seconds each. Then, it was transferred to a spin dryer, washed with deionized water (DIW), and dried with nitrogen for 15 seconds. The defect changes before and after polishing of the dried silicon wafer were measured using a defect measurement apparatus (model name: XP+, manufactured by KLA-TENCOR). Specifically, the total number of scratches, chatter marks, pits, and residues on the wafer was measured.

[0154]

Table 1

[0155] As can be seen from Table 1 above, the polishing pads of Examples 1 to 3 have excellent sound absorption rate characteristics, significantly fewer defects / scratches, and also excellent polishing rates. Specifically, the polishing pads of Examples 1 to 3 have a maximum sound absorption rate of 0.1 or more in the frequency range of 500 Hz to 4000 Hz, and are extremely excellent in sound absorption rate characteristics compared to Comparative Examples 1 and 2 which are conventional polishing pads (see Figure 1). Also, by satisfying that the maximum sound absorption rate of the polishing pads of Examples 1 to 3 is 0.1 or more in the frequency range of 500 Hz to 4000 Hz, in the CMP polishing process, energy loss due to thermal energy or vibration energy can be minimized, so the polishing rate is excellent compared to Comparative Examples 1 and 2, and the number of defects / scratches is also significantly less.

Explanation of Reference Signs

[0156] 100: Polishing Pad 200: Platen 300: Conditioner 400: Polishing Slurry 510: Polishing Head 520: Carrier 600: Semiconductor Substrate (Wafer)

Claims

1. Includes an abrasive layer, The polishing layer includes a urethane-based prepolymer, a foaming agent, and a curing agent, A polishing pad having a maximum sound absorption coefficient of 0.1 or more measured at frequencies of 500 Hz to 4000 Hz according to the following formula 1: [Formula 1] Sound absorption coefficient = (I ｉ -I ｒ ) / I ｉ = (I ａ +I ｔ ) / I ｉ In the above formula 1, Based on KS F 2814-2, when the polishing pad was cut (diameter: 45 mm) and the sound pressure was measured in an impedance tube, I ｉ is the incident sound intensity, I ｒ is the intensity of the reflected sound, and I ａ is the strength of absorbed sound, I ｔ is the transmitted sound intensity.

2. The polishing pad according to claim 1, wherein the maximum sound absorption coefficient measured at a frequency of 1000 Hz to 1500 Hz according to formula 1 is 0.05 or more, and the maximum sound absorption coefficient measured at a frequency of 1500 Hz to 3000 Hz is 0.1 or more.

3. The blowing agent comprises a solid phase blowing agent; The polishing pad according to claim 1, wherein the solid-phase foaming agent comprises at least one selected from the group consisting of acrylonitrile-based copolymers, methyl methacrylate-based copolymers, methacrylonitrile-based copolymers, and acrylic-based copolymers.

4. The solid phase blowing agent is The average particle size is 5 μm to 100 μm, 4. The polishing pad according to claim 3, wherein the content is 0.1 to 5 parts by weight based on 100 parts by weight of the urethane-based prepolymer.

5. The hardener is 4,4'-methylenebis(2-chloroaniline) (MOCA), diethyltoluenediamine (DETDA), 3,5-dimethylthio-2,6-diaminotoluene (DMTDA), 1,3-propanediol bis(4-aminobenzoate) (PDPAB), N,N'-bis(sec-butylamino)diphenylmethane, 2,6-bis(methylthio)-4-methyl-1,3-benzenediamine, 4-(4-aminobenzoyl)oxyphenyl 4-aminobenzoate, 4-(4-aminobenzoyl)oxybutyl 4-aminobenzoate, 4-[4-(4-aminobenzoyl)oxy-3-methylbutoxy]butyl 4-aminobenzoate, and methylene bis-methylanthranilate (MBNA). The polishing pad of claim 1, comprising one or more selected from the group consisting of these.

6. 2. The polishing pad according to claim 1, wherein the content of the curing agent is 5 parts by weight to 50 parts by weight based on 100 parts by weight of the urethane-based prepolymer.

7. 2. The polishing pad according to claim 1, wherein the equivalent ratio of said urethane-based prepolymer and said curing agent is 1:0.5-2.

8. The polishing layer is Hardness of 50 Shore D to 65 Shore D; 15N / mm ２ ~25N / mm ２ and a tensile strength of 2. The polishing pad of claim 1, having an elongation of 90% to 130%.

9. When the silicon oxide layer of the silicon wafer is polished with the ceria slurry using the polishing pad, the polishing rate is 2150 Å / min to 3500 Å / min according to the following mathematical formula 1:

2. The polishing pad according to claim 1, wherein when a silicon oxide layer of a silicon wafer is polished with a silica slurry using the polishing pad, the polishing rate is 3500 Å / min to 4500 Å / min according to the following mathematical formula 1: [Equation 1] Polishing rate (Å / min) = change in film thickness before and after polishing (Å) / polishing time (min).

10. 10. A method for manufacturing a semiconductor device, comprising the step of polishing a surface of a semiconductor substrate with the polishing pad of claim 1.

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