KR20220061708A - Polishing pad, manufacturing method thereof and preparing method of semiconductor device using the same - Google Patents

Abstract

The present invention provides a polishing pad and a manufacturing method thereof. According to the present invention, the polishing pad maintains the polishing performance required for the polishing process, such as the polishing rate and the polishing profile, minimizes defects that may occur on the wafer in the polishing process, and can polish films of different materials to have the same level of flatness even when simultaneously polished, and, when applying the polishing pad in the chemical mechanical polishing (CMP) process, can determine the polishing pad for controlling the optimal polishing selectivity along with the performance in the polishing process through the physical property values of the polishing pad without direct polishing tests.

Description

A polishing pad, a method of manufacturing a polishing pad, and a method of manufacturing a semiconductor device using the same

The present invention relates to a polishing pad used in a chemical mechanical planarization (CMP) process, a method of manufacturing the same, and a method of manufacturing a semiconductor device using the same.

In the chemical mechanical planarization (CMP) process of the semiconductor manufacturing process, in a state where a wafer is attached to a head and brought into contact with the surface of a polishing pad formed on a platen, a slurry is supplied to chemically prepare the wafer surface. It is a process of mechanically planarizing the uneven part of the wafer surface by moving the platen and the head relative to each other while reacting.

In general, when a CMP (Chemical Mechanical Polishing) process for forming a device isolation film of a semiconductor device is performed, in order to increase the polishing selectivity between the oxide film and the pad and the nitride film, the high selectivity of the ceria series has a large difference in the polishing rate between the oxide film and the pad and nitride film. Use a slurry. However, in the case of using a ceria-based abrasive, there is a problem that a sedimentation prevention device that can prevent sedimentation should be used instead of the existing equipment to prevent sedimentation due to agglomeration between particles.

In addition, when a ceria-based abrasive is used, a compound that increases the abrasive selectivity between the oxide film and the pad and nitride film is added. There is a problem of reducing the lifespan of

In order to solve this problem, it has been proposed to add a new device for mixing the ceria 　 abrasive and the added compound at the end of the slurry supply device. .

In the case of a ceria-based abrasive, the polishing speed for the oxide film is slower than that of the silica-based slurry, so the time required for the polishing process increases. Therefore, a silica-based slurry is used in the first process where only the oxide film is polished, and the oxide film and the pad and nitride film are used. A method of using a ceria-based abrasive has been proposed for the second process, which is simultaneously polished.

However, in this method, defects are highly likely to occur due to the difference in basic characteristics between the slurries, such as agglomeration due to the pH difference between the silica-based slurry and the ceria-based abrasive, and different heads are used on different platens. There is a problem in that the process is complicated and two equipments must be used.

As a result, there is a problem in that it is difficult to control the selectivity depending on the type of abrasive in the slurry. I need this.

It is an object of the present invention to provide a polishing pad and a method for manufacturing the same.

Another object of the present invention is to maintain the polishing performance required for the polishing process such as polishing rate and polishing profile, to minimize defects that may be generated on the wafer during the polishing process, and to ensure that the film quality of different materials is at the same level even when polishing at the same time. An object of the present invention is to provide a polishing pad capable of being polished to have a flatness of , and a method for manufacturing the same.

Another object of the present invention is to determine the polishing pad for controlling the optimum polishing selectivity as well as the performance on the polishing process through the physical property values of the polishing pad without a direct polishing test when the polishing pad is applied in the CMP process. and a manufacturing method thereof.

Another object of the present invention is to provide a method of manufacturing a semiconductor device to which a polishing pad is applied.

In order to achieve the above object, a polishing pad according to an embodiment of the present invention includes a polishing layer, and a value according to Equation 1 is 0.6 to 1:

[Equation 1]

Wherein H is the surface hardness of the polishing surface of the polishing layer (shore D),

The M is the elastic modulus of the polishing layer (N/mm ² ),

E is the elongation (%) of the polishing layer.

A method of manufacturing a polishing pad according to another embodiment of the present invention includes the steps of: i) preparing a prepolymer composition; ii) preparing a composition for preparing an abrasive layer comprising the prepolymer composition, a foaming agent and a curing agent; and iii) preparing an abrasive layer by curing the composition for preparing the abrasive layer, wherein the abrasive layer has a value of 0.6 to 1 according to Equation 1:

[Equation 1]

Wherein H is the surface hardness of the polishing surface of the polishing layer (shore D),

The M is the elastic modulus of the polishing layer (N/mm ² ),

E is the elongation (%) of the polishing layer.

A method of manufacturing a semiconductor device according to another embodiment of the present invention includes: 1) providing a polishing pad including a polishing layer; and 2) polishing the semiconductor substrate while relatively rotating so that the polished surface of the semiconductor substrate comes into contact with the polishing surface of the polishing layer, wherein the polishing layer has a value of 0.6 to 1 according to Equation 1 below:

[Equation 1]

Wherein H is the surface hardness of the polishing surface of the polishing layer (shore D),

The M is the elastic modulus of the polishing layer (N/mm ² ),

E is the elongation (%) of the polishing layer.

The polishing pad of the present invention maintains the polishing performance required for the polishing process such as the polishing rate and the polishing profile, minimizes defects that may occur on the wafer during the polishing process, and the film quality of different materials is at the same level even when polishing at the same time It can be polished to have a flatness of can

In addition, a method for manufacturing a semiconductor device to which a polishing pad is applied can be provided.

1 is a schematic process diagram of a semiconductor device manufacturing process according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail so that those of ordinary skill in the art can easily carry out the present invention. However, the present invention may be embodied in several different forms and is not limited to the embodiments described herein.

It should be understood that numbers expressing quantities of components, properties such as molecular weight, reaction conditions, etc. used in the present invention are modified by the term “about” in all instances.

In the present invention, unless otherwise stated, all percentages, parts, ratios, etc. are by weight.

In the present invention, when "included", it means that other components may be additionally included, rather than excluding other components, unless otherwise stated.

As used herein, “a plurality” refers to more than one.

A polishing pad according to an embodiment of the present invention includes a polishing layer, and a value according to Equation 1 is 0.6 to 1:

[Equation 1]

Wherein H is the surface hardness of the polishing surface of the polishing layer (shore D),

The M is the elastic modulus of the polishing layer (N/mm ² ),

E is the elongation (%) of the polishing layer.

In addition, the polishing layer of the present invention may have a value of 0.6 to 1 according to Equation 2:

[Equation 2]

here,

H, M and E are as defined in Formula 1 above.

The polishing layer includes a cured product obtained by curing a composition including a urethane-based prepolymer, a curing agent, and a foaming agent, and the urethane-based prepolymer may be prepared by reacting a polyol and an isocyanate.

The equivalents of curing reactors such as amine groups (-NH ₂ ) and alcohol groups (-OH) of the curing agent and isocyanate groups (-NCO) of the prepolymer are determined by the type and content of the curing agent that may be included in the preparation of the polishing layer, The molding temperature of the mold determines the curing rate and the sequential sequence of chemical reactions.

The final urethane-based cured structure of the polishing pad is determined by these factors. By the final urethane-based curing structure, the physical/mechanical properties of the abrasive layer may be expressed as properties such as hardness, elastic modulus, and elongation.

In particular, when the value according to Equation 1 by the hardness, elastic modulus, and elongation of the polishing layer of the present invention is 0.6 to 1, it is possible to control particularly the polishing selectivity among polishing performance of a polishing object containing an oxide film and a nitride film.

In general, the polishing selectivity of the nitride layer to the oxide layer should be controlled to prevent a dishing phenomenon and to minimize defects that may occur in the wafer.

When the polishing selectivity of the nitride layer to the oxide layer is small, a dishing phenomenon in which the oxide layer is excessively removed due to loss of an adjacent nitride layer pattern occurs, and thus a uniform surface planarization cannot be achieved.

In addition, when the polishing selectivity of the nitride layer to the oxide layer is large, the upper layer is excessively removed and a recess occurs, and the insulating layer or barrier layer collapses due to the physical action of the abrasive particles (erosion). ) can be exacerbated.

That is, the polishing pad of the present invention is characterized in that the surface planarization of the target film in the semiconductor substrate is achieved by controlling the polishing selectivity for the oxide film and the nitride film in a certain range.

Equations 1 and 2 define weights for hardness, elastic modulus, and elongation, and calculate values accordingly. Through the relationship between hardness, elastic modulus, and elongation according to the above formula, the oxide film of the polishing pad and It is possible to adjust the polishing selectivity (Ox RR/Nt RR) of the nitride film.

That is, the abrasive layer includes a urethane-based prepolymer, and the physical/mechanical characteristics of hardness, elastic modulus, and elongation are affected by the cured structure of the urethane-based prepolymer.

The physical/mechanical properties of the polishing layer correspond to factors that directly affect the polishing rate when the polishing pad is applied to the polishing process. Differences in the polishing rate for the target film due to differences in hardness, elastic modulus, and elongation will appear

Controlling the polishing rate is, as described above, when the target film quality is an oxide layer and a nitride layer, by finely adjusting the polishing rate for each target film quality, it will be possible to prevent the occurrence of defects.

Among the physical/mechanical properties of the abrasive layer, hardness, elastic modulus, and elongation are important factors affecting the polishing rate of the target film. will say it is possible to perform.

Therefore, in the present invention, weights are given to hardness, elastic modulus, and elongation as in Equation 1 and Equation 2, and by specifying the values, the polishing selectivity for the oxide film and the nitride film is adjusted to exhibit excellent polishing performance. can

In another embodiment, in the CMP polishing process, the application of the polishing pad requires a polishing test to confirm that the polishing selectivity is suitable for the process.

Specifically, in the CMP polishing process, it is necessary to check the polishing rate for the oxide film and the nitride film, and the confirmation of the polishing rate was only possible through a numerical value confirmed through a direct polishing test.

However, as with the polishing pad of the present invention, if the values of the physical properties for hardness, elastic modulus, and elongation of the polishing surface are checked, and the values are substituted in Equation 2 or 3 to derive the values, an oxide film and a nitride film An expected value of the polishing selectivity to (Nitride) can be derived, which will allow the use of the polishing pad without polishing testing.

The polishing pad of the present invention is characterized in that the polishing selectivity (Ox RR/Nt RR) of the oxide film and the nitride film is 25 to 40 or 30 to 35.

The polishing selectivity is calculated by measuring polishing rates for the oxide film and the nitride film.

Specifically, the polishing rate for the oxide film uses a silicon wafer having a diameter of 300 mm on which a silicon oxide (SiOx) film is deposited, the polishing load is 1.4 psi, and the ceria slurry is put into the polishing surface at a rate of 190 ml/min, A surface plate equipped with a polishing pad was rotated at a speed of 115 rpm, and the silicon oxide film was polished for 60 seconds, the thickness was measured, and the polishing rate was calculated using the difference in thickness from before polishing.

For the polishing rate for the nitride film, a silicon wafer having a diameter of 300 mm on which an SiN film is deposited is used, a polishing load is 1.4 psi, a ceria slurry is introduced into the polishing surface at a rate of 190 ml/min, and a surface plate equipped with a polishing pad was rotated at a speed of 115 rpm, the SiN film was polished for 60 seconds, the thickness was measured, and the polishing rate was calculated using the difference in thickness from before polishing.

In one embodiment, the polishing layer may include an abrasive layer including a cured product formed from a composition including a urethane-based prepolymer, a curing agent, and a foaming agent.

Each component included in the composition will be specifically described below.

The term 'prepolymer' refers to a polymer having a relatively low molecular weight in which the polymerization degree is stopped at an intermediate stage to facilitate molding in the production of a cured product. The prepolymer can be molded into a final cured product either on its own or after reacting with other polymerizable compounds.

In one embodiment, the urethane-based prepolymer may be prepared by reacting an isocyanate compound with a polyol.

As the isocyanate compound used in the preparation of the urethane-based prepolymer, one selected from the group consisting of aromatic diisocyanate, aliphatic diisocyanate, cycloaliphatic diisocyanate, and combinations thereof may be used.

The isocyanate compound is, for example, 2,4-toluenediisocyanate (2,4-TDI), 2,6-toluenediisocyanate (2,6-toluenediisocyanate, 2,6-TDI) Naphthalene-1,5-diisocyanate, para-phenylenediisocyanate, tolidinediisocyanate, 4,4'-diphenylmethane diisocyanate (4,4) It may include one selected from the group consisting of '-diphenylmethanediisocyanate), hexamethylenediisocyanate, dicyclohexylmethanediisocyanate, isophorone diisocyanate, and combinations thereof.

The 'polyol' refers to a compound including at least two hydroxyl groups (-OH) per molecule. The polyol is, for example, one selected from the group consisting of polyether polyol, polyester polyol, polycarbonate polyol, acrylic polyol, and combinations thereof. may include

The polyol is, for example, 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 , may include one selected from the group consisting of tripropylene glycol and combinations thereof.

The polyol may have a weight average molecular weight (Mw) of about 100 g/mol to about 3,000 g/mol. The polyol may have a weight average of, for example, from about 100 g/mol to about 3,000 g/mol, such as from about 100 g/mol to about 2,000 g/mol, such as from about 100 g/mol to about 1,800 g/mol. It may have a molecular weight (Mw).

In one embodiment, the polyol is a low molecular weight polyol having a weight average molecular weight (Mw) of about 100 g/mol or more and less than about 300 g/mol, and a high molecular weight having a weight average molecular weight (Mw) of about 300 g/mol or more and about 1800 g/mol or less polyols.

The urethane-based prepolymer may have a weight average molecular weight (Mw) of about 500 g/mol to about 3,000 g/mol. The urethane-based prepolymer may have a weight average molecular weight (Mw) of, for example, about 600 g/mol to about 2,000 g/mol, for example, about 800 g/mol to about 1,000 g/mol.

In one embodiment, the isocyanate compound for preparing the urethane-based prepolymer may include an aromatic diisocyanate compound, and the aromatic diisocyanate compound is, for example, 2,4-toluene diisocyanate (2,4-TDI) and 2,6-toluenediisocyanate (2,6-TDI). The polyol compound for preparing the urethane-based prepolymer may include polytetramethylene ether glycol (PTMEG) and diethylene glycol (DEG).

In another embodiment, the isocyanate compound for preparing the urethane-based prepolymer may include an aromatic diisocyanate compound and an alicyclic diisocyanate compound, for example, the aromatic diisocyanate compound is 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-based prepolymer may include polytetramethylene ether glycol (PTMEG) and diethylene glycol (DEG).

The urethane-based prepolymer has an isocyanate end group content (NCO%) of about 5 wt% to about 11 wt%, for example, about 5 wt% to about 10 wt%, for example, about 5 wt% to about 8 wt% , for example, from about 8% to about 10% by weight. When the NCO% is within the above range, the physical properties of the polishing layer in the appropriate polishing pad are maintained, the polishing performance required for the polishing process such as the polishing rate and the polishing profile is maintained, and defects that may be generated on the wafer during the polishing process are minimized. can

In addition, by controlling the polishing selectivity (Ox RR/Nt RR) of the oxide film and the nitride film, dishing, recess, and erosion are prevented, and the surface in the wafer is planarized. can be achieved

The isocyanate end group content (NCO%) of the urethane-based prepolymer is determined by the type and content of the isocyanate compound and polyol compound for preparing the urethane-based prepolymer, the process conditions such as temperature, pressure, and time of the process for preparing the urethane-based prepolymer, and the urethane-based prepolymer It can be designed by comprehensively controlling the type and content of additives used in the preparation of the prepolymer.

The curing agent is a compound for chemically reacting with the urethane-based prepolymer to form a 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.

For example, the curing agent is 4,4'-methylenebis(2-chloroaniline) (4,4'-methylenebis(2-chloroaniline); MOCA), diethyltoluenediamine (DETDA), diaminodiphenyl Methane (diaminodiphenylmethane), dimethyl thio-toluene diamine (DMTDA), propanediol bis p-aminobenzoate (propanediol bis p-aminobenzoate), Methylene bis-methylanthranilate, diaminodiphenylsulfone (diaminodiphenylsulfone), m -xylylenediamine, isophoronediamine, ethylenediamine, diethylenetriamine, triethylenetetramine, polypropylenediamine, polypropylenetriamine (polypropylenetriamine), bis (4-amino-3-chlorophenyl) methane (bis (4-amino-3-chlorophenyl) methane), and may include one selected from the group consisting of combinations thereof.

The amount of the curing agent is about 18 parts by weight to about 27 parts by weight, for example, about 19 parts by weight to about 26 parts by weight, for example, about 20 parts by weight to about 26 parts by weight based on 100 parts by weight of the urethane-based prepolymer. can When the content of the curing agent satisfies the above range, it may be more advantageous to realize the desired performance of the polishing pad.

The foaming agent may include one selected from the group consisting of a solid foaming agent, a gaseous foaming agent, a liquid foaming agent, and a combination thereof as a component for forming a pore structure in the polishing layer. In one embodiment, the foaming agent may include a solid foaming agent, a gas phase foaming agent, or a combination thereof.

The average particle diameter of the solid foaming agent is about 5 μm to about 200 μm, for example, about 20 μm to about 50 μm, for example, about 21 μm to about 50 μm, for example, about 25 μm to about 45 μm. can be The average particle diameter of the solid foaming agent means the average particle diameter of the thermally expanded particles themselves when the solid foaming agent is thermally expanded particles as described below, and the solid foaming agent is an unexpanded particle as described below. In this case, it may mean the average particle diameter of the particles after being expanded by heat or pressure.

The solid blowing agent may include expandable particles. The expandable particles are particles having a property of being expandable by heat or pressure, and the size in the final abrasive layer may be determined by heat or pressure applied during the manufacturing process of the abrasive layer. The expandable particles may include thermally expanded particles, unexpanded particles, or a combination thereof. The thermally expanded particles are particles pre-expanded by heat, and refer to particles having little or no size change due to heat or pressure applied during the manufacturing process of the abrasive layer. The unexpanded particles are non-expanded particles, and refer to particles whose final size is determined by being expanded by heat or pressure applied during the manufacturing process of the abrasive layer.

The expandable particles may include a resin material; And it may include an expansion-inducing component present in the interior enclosed by the shell.

For example, the outer shell may include a thermoplastic resin, and the thermoplastic resin is selected from the group consisting of a vinylidene chloride-based copolymer, an acrylonitrile-based copolymer, a methacrylonitrile-based copolymer, and an acrylic copolymer. may be more than one species.

The expansion-inducing component may include one selected from the group consisting of a hydrocarbon compound, a chlorofluoro compound, a tetraalkylsilane compound, and combinations thereof.

Specifically, the hydrocarbon compound is ethane, ethylene, propane, propene, n-butane, isobutene, n-butene, isobutene, n-pentane, isopentane, neopentane, n-hexane, heptane, petroleum ether, and their It may include one selected from the group consisting of combinations.

The chlorofluoro compound is trichlorofluoromethane (trichlorofluoromethane, CCl3F), dichlorodifluoromethane (CCl2F2), chlorotrifluoromethane (chlorotrifluoromethane, CClF3), tetrafluoroethylene (tetrafluoroethylene, CClF ₂ -CClF) ₂ ) and may include one selected from the group consisting of combinations thereof.

The tetraalkylsilane compound is selected from the group consisting of tetramethylsilane, trimethylethylsilane, trimethylisopropylsilane, trimethyl-n-propylsilane, and combinations thereof. may contain one.

The solid foaming agent may optionally include inorganic component-treated particles. For example, the solid blowing agent may include inorganic component-treated expandable particles. In one embodiment, the solid foaming agent may include silica (SiO ₂ ) particle-treated expandable particles. The inorganic component treatment of the solid foaming agent can prevent aggregation between a plurality of particles. The inorganic component-treated solid foaming agent may have different chemical, electrical and/or physical properties of the surface of the foaming agent surface than the inorganic component-treated solid foaming agent.

The amount of the solid foaming agent is about 0.5 parts by weight to about 10 parts by weight, for example, about 1 part by weight to about 3 parts by weight, for example, about 1.3 parts by weight to about 2.7 parts by weight based on 100 parts by weight of the urethane-based prepolymer. parts, for example from about 1.3 parts by weight to about 2.6 parts by weight.

The type and content of the solid foaming agent may be designed according to the desired pore structure and physical properties of the polishing layer.

The gas-phase foaming agent may include an inert gas. The gas-phase foaming agent may be used as a pore-forming element by being added during a reaction between the urethane-based prepolymer and the curing agent.

The type of the inert gas is not particularly limited as long as it does not participate in the reaction between the urethane-based prepolymer and the curing agent. For example, the inert gas may include one selected from the group consisting of nitrogen gas (N ₂ ), argon gas (Ar), helium gas (He), and combinations thereof. Specifically, the inert gas may include nitrogen gas (N2) or argon gas (Ar).

The type and content of the gas-phase foaming agent can be designed according to the desired pore structure and physical properties of the abrasive layer.

In one embodiment, the foaming agent may include a solid foaming agent. For example, the foaming agent may be formed of only a solid foaming agent.

The solid foaming agent may include expandable particles, and the expandable particles may include thermally expanded particles. For example, the solid foaming agent may consist only of thermally expanded particles. In the case of not including the unexpanded particles but only the thermally expanded particles, the variability of the pore structure is reduced, but the predictability is increased, so it may be advantageous to implement homogeneous pore properties over the entire area of the abrasive layer.

In one embodiment, the thermally expanded particles may be particles having an average particle diameter of about 5 μm to about 200 μm. The average particle diameter of the thermally expanded particles is about 5 μm to about 100 μm, for example, about 10 μm to about 80 μm, for example, about 20 μm to about 70 μm, for example, about 20 μm to about 50 μm. μm, for example from about 30 μm to about 70 μm, such as from about 25 μm to 45 μm, such as from about 40 μm to about 70 μm, such as from about 40 μm to about 60 μm there is. The average particle diameter is defined as the D50 of the thermally expanded particles.

In one embodiment, the density of the thermally expanded particles is from about 30 kg/m to about 80 kg/m, such as from about 35 kg/m to about 80 kg/m, such as from about 35 kg/m to about 75 kg/m, For example, it may be from about 38 kg/m to about 72 kg/m, such as from about 40 kg/m to about 75 kg/m, such as from about 40 kg/m to about 72 kg/m.

In one embodiment, the foaming agent may include a gas phase foaming agent. For example, the foaming agent may include a solid foaming agent and a gas phase foaming agent. Matters regarding the solid foaming agent are the same as described above.

The gas-phase foaming agent may include nitrogen gas.

The vapor-phase foaming agent may be injected through a predetermined injection line while the urethane-based prepolymer, the solid-state foaming agent, and the curing agent are mixed. The injection rate of the gas phase blowing agent is from about 0.8 L/min to about 2.0 L/min, such as from about 0.8 L/min to about 1.8 L/min, such as from about 0.8 L/min to about 1.7 L/min. , for example, from about 1.0 L/min to about 2.0 L/min, such as from about 1.0 L/min to about 1.8 L/min, such as from about 1.0 L/min to about 1.7 L/min there is.

The composition for preparing the polishing layer may further include other additives such as a surfactant and a reaction rate controlling agent. The names such as 'surfactant' and 'reaction rate regulator' are arbitrary names based on the main role of the corresponding substance, and each corresponding substance does not necessarily perform only a function limited to the role by the corresponding name.

The surfactant is not particularly limited as long as it is a material that serves to prevent aggregation or overlapping of pores. For example, the surfactant may include a silicone-based surfactant.

The surfactant may be used in an amount of about 0.2 parts by weight to about 2 parts by weight based on 100 parts by weight of the urethane-based prepolymer. Specifically, the surfactant is about 0.2 parts by weight to about 1.9 parts by weight, for example, about 0.2 parts by weight to about 1.8 parts by weight, for example, about 0.2 parts by weight to about 1.7 parts by weight based on 100 parts by weight of the urethane-based prepolymer. It may be included in an amount of, for example, about 0.2 parts by weight to about 1.6 parts by weight, for example, about 0.2 parts by weight to about 1.5 parts by weight, for example, about 0.5 parts by weight to 1.5 parts by weight. When the surfactant is included in an amount within the above range, pores derived from the gas-phase foaming agent may be stably formed and maintained in the mold.

The reaction rate controlling agent serves to promote or delay the reaction, and depending on the purpose, a reaction accelerator, a reaction retarder, or both may be used. The reaction rate controlling agent may include a reaction accelerator. For example, the reaction accelerator may be one or more reaction accelerators selected from the group consisting of a tertiary amine-based compound and an organometallic compound.

Specifically, the reaction rate controlling agent is 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, dimethylamino Propylamine, benzyldimethylamine, N-ethylmorpholine, N,N-dimethylaminoethylmorpholine, N,N-dimethylcyclohexylamine, 2-methyl-2-azanovonein, dibutyltin dilaurate, Contains at least one selected from the group consisting of stannous octoate, dibutyltin diacetate, dioctyltin diacetate, dibutyltin maleate, dibutyltin di-2-ethylhexanoate and dibutyltin dimercaptide can do. Specifically, the reaction rate controlling agent may include at least one selected from the group consisting of benzyldimethylamine, N,N-dimethylcyclohexylamine and triethylamine.

The reaction rate controlling agent may be used in an amount of about 0.05 parts by weight to about 2 parts by weight based on 100 parts by weight of the urethane-based prepolymer. Specifically, the reaction rate controlling agent is about 0.05 parts by weight to about 1.8 parts by weight, for example, about 0.05 parts by weight to about 1.7 parts by weight, for example, about 0.05 parts by weight to about 100 parts by weight of the urethane-based prepolymer. 1.6 parts by weight, such as about 0.1 parts by weight to about 1.5 parts by weight, such as about 0.1 parts by weight to about 0.3 parts by weight, such as about 0.2 parts by weight to about 1.8 parts by weight, for example, about 0.2 parts by weight to about 1.7 parts by weight, such as about 0.2 parts by weight to about 1.6 parts by weight, such as about 0.2 parts by weight to about 1.5 parts by weight, such as about 0.5 parts by weight to about 1 parts by weight. It can be used in negative amounts. When the reaction rate controlling agent is used in the above-described content range, the curing reaction rate of the prepolymer composition may be appropriately adjusted to form an abrasive layer having pores of a desired size and hardness.

When the polishing pad includes a cushion layer, the cushion layer serves to absorb and disperse an external impact applied to the polishing layer while supporting the polishing layer, thereby causing damage to the polishing object during the polishing process to which the polishing pad is applied. And it is possible to minimize the occurrence of defects.

The cushion layer may include, but is not limited to, nonwoven fabric or suede.

In one embodiment, the cushion layer may be a resin-impregnated nonwoven fabric. The nonwoven fabric may be a fiber nonwoven fabric including one selected from the group consisting of polyester fibers, polyamide fibers, polypropylene fibers, polyethylene fibers, and combinations thereof.

The resin impregnated into the nonwoven fabric is a 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 , it may include one selected from the group consisting of a polyester-based elastomer resin, a polyamide-based elastomer resin, and combinations thereof.

Hereinafter, a method of manufacturing the polishing pad will be described in detail.

In another embodiment according to the present invention, the method comprising the steps of preparing a prepolymer composition; preparing a composition for preparing an abrasive layer comprising the prepolymer composition, a foaming agent and a curing agent; and curing the composition for preparing the polishing layer to prepare a polishing layer.

The preparing of the prepolymer composition may be a process of preparing a urethane-based prepolymer by reacting a diisocyanate compound and a polyol compound. The diisocyanate compound and the polyol compound are the same as those described above with respect to the polishing pad.

The isocyanate group (NCO group) content of the prepolymer composition is from about 5% to about 15% by weight, for example, from about 5% to about 8% by weight, for example, from about 5% to about 7% by weight, For example, from about 8% to about 15% by weight, such as from about 8% to about 14% by weight, such as from about 8% to about 12% by weight, such as from 8% to about 12% by weight It may be about 10% by weight.

The isocyanate group content of the prepolymer composition may be derived from terminal isocyanate groups of the urethane-based prepolymer, unreacted unreacted isocyanate groups in the diisocyanate compound, and the like.

The viscosity of the prepolymer composition may be from about 100 cps to about 1,000 cps at about 80° C., for example, from about 200 cps to about 800 cps, for example, from about 200 cps to about 600 cps, for example, It may be from about 200 cps to about 550 cps, for example, from about 300 cps to about 500 cps.

The foaming agent may include a solid foaming agent or a gas phase foaming agent.

When the foaming agent includes a solid foaming agent, preparing the composition for preparing an abrasive layer may include preparing a first preliminary composition by mixing the prepolymer composition and the solid foaming agent; and mixing the first preliminary composition and a curing agent to prepare a second preliminary composition.

The viscosity of the first preliminary composition may be from about 1,000 cps to about 2,000 cps at about 80° C., for example, from about 1,000 cps to about 1,800 cps, for example, from about 1,000 cps to about 1,600 cps. may be, for example, about 1,000 cps to about 1,500 cps.

When the foaming agent includes a gas-phase foaming agent, preparing the composition for preparing the polishing layer may include preparing a third preliminary composition including the prepolymer composition and the curing agent; and injecting the gas-phase foaming agent into the third preliminary composition to prepare a fourth preliminary composition.

In one embodiment, the third preliminary composition may further include a solid foaming agent.

In one embodiment, the process of manufacturing the polishing layer comprises: preparing a mold preheated to a first temperature; and injecting and curing the composition for preparing the polishing layer into the preheated mold; and post-curing the cured composition for preparing the polishing layer under a second temperature condition higher than the preheating temperature.

In one embodiment, the first temperature may be about 60 °C to about 100 °C, for example, about 60 °C to about 95 °C, for example, about 60 °C to about 80 °C.

In one embodiment, the second temperature may be from about 100°C to about 130°C, for example, from about 100°C to 125°C, for example, from about 100°C to about 120°C.

The step of curing the composition for preparing an abrasive layer under the first temperature is about 5 minutes to about 60 minutes, for example, about 5 minutes to about 40 minutes, for example, about 5 minutes to about 30 minutes, for example , from about 5 minutes to about 25 minutes.

The step of post-curing the composition for preparing an abrasive layer cured under the first temperature under the second temperature is about 5 hours to about 30 hours, for example, about 5 hours to about 25 hours, for example, about 10 hours to about 10 hours. about 30 hours, such as about 10 hours to about 25 hours, such as about 12 hours to about 24 hours, such as about 15 hours to about 24 hours.

The method of manufacturing the polishing pad may include processing at least one surface of the polishing layer. The processing step may be to form a groove (groove).

In another embodiment, the machining of at least one surface of the polishing layer may include: (1) forming a groove on at least one surface of the polishing layer; line turning (2) at least one surface of the abrasive layer; and roughening at least one surface of the polishing layer (3).

In the step (1), the groove (groove) is a concentric circular groove formed spaced apart from the center of the polishing layer at a predetermined interval; and at least one of a radial groove continuously connected from the center of the polishing layer to an edge of the polishing layer.

In the step (2), the line turning may be performed by using a cutting tool to cut the abrasive layer by a predetermined thickness.

In step (3), the roughening may be performed by processing the surface of the abrasive layer with a sanding roller.

The method of manufacturing the polishing pad may further include laminating a cushion layer on the back surface of the polishing surface of the polishing layer.

The abrasive layer and the cushion layer may be laminated using a heat-sealing adhesive.

The heat sealing adhesive is applied on the back surface of the polishing surface of the polishing layer, the heat sealing adhesive is applied on the surface to be in contact with the polishing layer of the cushion layer, and the surfaces to which each heat sealing adhesive is applied are in contact After laminating the abrasive layer and the cushion layer to the surface, the two layers may be fusion-bonded using a pressure roller.

In yet another embodiment, the method comprising: providing a polishing pad including a polishing layer; and grinding the polishing object while relatively rotating the polishing surface of the polishing layer so that the polished surface of the polishing object is in contact with the polishing surface.

1 is a schematic flowchart of a semiconductor device manufacturing process according to an exemplary embodiment. Referring to FIG. 1 , after the polishing pad 110 according to the embodiment is mounted on the surface plate 120 , a semiconductor substrate 130 to be polished is disposed on the polishing pad 110 . At this time, the polished surface of the semiconductor substrate 130 is in direct contact with the polishing surface of the polishing pad 110 . For polishing, the polishing slurry 150 may be sprayed on the polishing pad through the nozzle 140 . The flow rate of the polishing slurry 150 supplied through the nozzle 140 may be selected according to the purpose within the range of about 10 cm 3 /min to about 1,000 cm 3 /min, for example, from about 50 cm 3 /min to about It may be 500 ㎤ / min, but is not limited thereto.

Thereafter, the semiconductor substrate 130 and the polishing pad 110 may be rotated relative to each other, so that the surface of the semiconductor substrate 130 may be polished. In this case, the rotation direction of the semiconductor substrate 130 and the rotation direction of the polishing pad 110 may be in the same direction or in opposite directions. The rotation speed of the semiconductor substrate 130 and the polishing pad 110 may be selected depending on the purpose in the range of about 10 rpm to about 500 rpm, respectively, for example, it may be about 30 rpm to about 200 rpm, However, the present invention is not limited thereto.

The semiconductor substrate 130 is mounted on the polishing head 160 and is pressed against the polishing surface of the polishing pad 110 by a predetermined load to abut the surface, and then the surface may be polished. The load applied to the polishing surface of the polishing pad 110 on the surface of the semiconductor substrate 130 by the polishing head 160 may be selected in the range of about 1 gf/cm 2 to about 1,000 gf/cm 2 depending on the purpose. and may be, for example, about 10 gf/cm 2 to about 800 gf/cm 2 , but is not limited thereto.

In one embodiment, in the method of manufacturing the semiconductor device, in order to maintain the polishing surface of the polishing pad 110 in a state suitable for polishing, the semiconductor substrate 130 is polished and the conditioner 170 is used simultaneously with the polishing. The method may further include processing the polishing surface of the pad 110 .

Hereinafter, specific embodiments of the present invention are presented. However, the examples described below are only for specifically illustrating or explaining the present invention, and the present invention is not limited thereto.

Example 1

Manufacture of polishing pad

In a casting equipment equipped with a mixture injection line of a urethane-based prepolymer, a curing agent, and a solid foaming agent, a prepolymer tank is filled with a urethane-based prepolymer having 9 wt% of unreacted NCO, and the curing agent tank is bis(4-amino-3-chlorophonyl) Methane (bis(4-amino-3-chlorophenyl)methane, manufactured by Ishihara) was charged. In addition, 3 parts by weight of a solid foaming agent was mixed in advance with respect to 100 parts by weight of the urethane-based prepolymer, and then injected into the prepolymer tank.

Through each input line, the urethane-based prepolymer and the curing agent were added to the mixing head at a constant speed while stirring. At this time, the molar equivalent of the NCO group of the urethane-based prepolymer and the molar equivalent of the reactive group of the curing agent were adjusted to 1:1, and the total input amount was maintained at a rate of 10 kg/min.

The stirred raw material was poured into a preheated mold, and a single porous polyurethane sheet was prepared. Thereafter, the surface of the prepared porous polyurethane sheet was ground using a grinding machine, and was manufactured to have an average thickness of 2 mm and an average diameter of 76.2 cm through a process of grooved using a tip.

The polyurethane sheet and suede (base layer, average thickness: 1.1 mm) were heat-sealed at 120° C. using a hot melt film (manufacturer: SKC, product name: TF-00) to prepare a polishing pad.

A urethane-based prepolymer having an NCO functional group at the terminal was prepared as follows. It was mixed with 90 parts by weight of toluene diisocyanate and 10 parts by weight of dicyclohexylmethane diisocyanate based on 100 parts by weight of the total diisocyanate component. Based on 100 parts by weight of the total weight of the polyol component, 90 parts by weight of PTMEG (molecular weight (MW) 1,000) and 10 parts by weight of DEG were mixed. Each mixed raw material was prepared in an amount of 152 parts by weight of the total amount of the polyol relative to 100 parts by weight of the total amount of the diisocyanate. Each of the mixed raw materials was put into a four-neck flask and reacted at 80° C. to prepare a preliminary composition having a urethane group. The content of isocyanate groups (NCO groups) in the always-prepared composition was prepared to be 8.8 to 9.4%.

Examples 2 to 4, Comparative Example 1 and Comparative Example 2

When the stirred raw material was injected into the mold, it was prepared in the same manner as in Example 1, except that the heating temperature was changed as shown in Table 1 below.

Example 1 Example 2 Example 3 Example 4 Comparative Example 1 Comparative Example 2 Prepolymer Terminal NCO content 8.8~9.4% hardener
(parts by weight) 25 25 25 25 25 25 Mold injection temperature (℃) 65 60 70 80 50 90

(The curing agent is based on 100 parts by weight of the urethane-based prepolymer)

test example

Measurement of physical properties of polishing pad

(1) hardness

1) Shore D hardness of the polishing pad prepared according to the above Examples and Comparative Examples was measured, and the polishing pad was cut to a size of 2 cm Х 2 cm (thickness: 2 mm), temperature 25 ℃ and humidity 50±5% It was left standing for 16 hours in an environment of Thereafter, the hardness of the polishing pad was measured using a durometer (D-type durometer).

(2) elastic modulus

For each of the polishing pads manufactured according to the above Examples and Comparative Examples, the highest strength value just before fracture was obtained while testing at a speed of 500 mm/min using a universal testing machine (UTM), and then, through the obtained value, strain-Stress The slope in the region of 20 to 70% of the curve was calculated.

(3) elongation

For each of the polishing pads manufactured according to the above Examples and Comparative Examples, the maximum amount of deformation immediately before fracture was measured while testing at a speed of 500 mm/min using a universal testing machine (UTM), and then the ratio of the maximum amount of deformation to the initial length was expressed as a percentage (%).

(4) Measurement of polishing rate

<Abrasion rate for oxide (O) film>

Using CMP polishing equipment, a silicon wafer having a diameter of 300 mm on which a silicon oxide (SiOx) film was formed by a TEOS-plasma CVD process was installed. Thereafter, the silicon oxide film of the silicon wafer was set downward on the surface plate to which the polishing pad was attached. Thereafter, the polishing load was adjusted to be 1.4 psi, and the polishing slurry (ceria slurry) was fed onto the polishing pad at a rate of 190 ml/min and the surface plate was rotated at 115 rpm for 60 seconds to polish the silicon oxide film. After polishing, the silicon wafer was removed from the carrier, mounted on a spin dryer, washed with purified water (DIW), and then dried with air for 15 seconds. The thickness difference between the dried silicon wafers before and after polishing was measured using an optical interference thickness measuring device (manufacturer: Kyence, model name: SI-F80R). Thereafter, the polishing rate was calculated using Equation 1 above.

<Removing rate for silicon nitride (SiN) film>

A silicon wafer having a diameter of 300 mm on which a SiN film was formed by a CVD process was installed using CMP polishing equipment. Thereafter, the SiN film of the silicon wafer was set down on the surface to which the polishing pad was attached. Thereafter, the polishing load was adjusted to 1.4 psi, and the polishing slurry (ceria slurry) was fed onto the polishing pad at a rate of 190 ml/min while rotating the platen at 115 rpm for 60 seconds to polish the SiN film. After polishing, the silicon wafer was removed from the carrier, mounted on a spin dryer, washed with purified water (DIW), and then dried with air for 15 seconds. The thickness difference between the dried silicon wafers before and after polishing was measured using an optical interference thickness measuring device (manufacturer: Kyence, model name: SI-F80R). Thereafter, the polishing rate was calculated using Equation 1 above.

<Equation 1>

Polishing rate (Å/min) = difference in thickness before and after polishing (Å)/polishing time (min)

The physical properties and the polishing rate of the polishing pads of Examples and Comparative Examples were measured by the method for measuring physical properties, and the results are shown in Table 2 below.

Example 1 Example 2 Example 3 Example 4 Comparative Example 1 Comparative Example 2 Hardness
(H, shore D) 57.7 56.2 56.9 57.5 55.5 58.5 modulus
(M, N/㎟) 110.3 123.1 135.2 121.1 60.6 111 Elongation (E, %) 80.3 80.1 81.1 81.9 58.6 142.9 TEOS(Oxide) RR
(Å/min) 2210 2195 2384 2135 1999 2088 Nitride RR(Å/min) 67.7 76.1 65.3 48.5 96 67.2 Ox RR/Nt RR 32.9 32.4 31.3 32.7 41.2 21.8 (0.1H + 0.3M + 0.6E)/100 0.870 0.906 0.949 0.912 0.589 1.249 (0.1H + 0.2M + 0.7E)/100 0.840 0.863 0.895 0.873 0.587 1.281

According to the values shown in Table 2, the polishing pads of Examples 1 to 4 showed some differences in hardness, modulus, and elongation compared to Comparative Examples. In particular, as a result of checking the value according to the formula according to the relationship between the physical properties of the polishing pad, it was confirmed that the value was within a specific range in the case of the present invention, and when the value is within the range, it is possible to control the polishing rate Confirmed.

Although preferred embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements by those skilled in the art using the basic concept of the present invention as defined in the following claims are also provided. is within the scope of the

110: polishing pad
120: surface plate
130: semiconductor substrate
140: nozzle
150: polishing slurry
160: abrasive head
170: conditioner

Claims (10)

comprising an abrasive layer;
A value of 0.6 to 1 according to Equation 1 below
Polishing Pad:
[Equation 1]

Wherein H is the surface hardness of the polishing surface of the polishing layer (shore D),
The M is the elastic modulus of the polishing layer (N/mm ² ),
E is the elongation (%) of the polishing layer. According to claim 1,
The polishing layer has a value of 0.6 to 1 according to Equation 2 below.
Polishing Pad:
[Equation 2]

here,
H, M and E are the same as in claim 1. According to claim 1,
The polishing layer has a polishing selectivity (Ox RR/Nt RR) of 25 to 40 of an oxide film and a nitride film.
polishing pad. According to claim 1,
The surface hardness of the abrasive layer at 25° C. with respect to the abrasive surface is 45 to 65 shore D.
polishing pad. According to claim 1,
The abrasive layer has an elastic modulus (Modulus) of 70 to 200 N/mm ²
polishing pad. According to claim 1,
The abrasive layer has an elongation of 60 to 140%.
polishing pad. i) preparing a prepolymer composition;
ii) preparing a composition for preparing an abrasive layer comprising the prepolymer composition, a foaming agent and a curing agent; and
iii) curing the composition for preparing an abrasive layer to prepare an abrasive layer;
The polishing layer has a value of 0.6 to 1 according to Equation 1 below.
A method of manufacturing a polishing pad:
[Equation 1]

Wherein H is the surface hardness of the polishing surface of the polishing layer (shore D),
The M is the elastic modulus of the polishing layer (N/mm ² ),
E is the elongation (%) of the polishing layer. 8. The method of claim 7,
Step iii) is to inject and harden the composition for preparing an abrasive layer into a preheated mold,
The preheating temperature of the mold is 60 to 80 ℃
A method for manufacturing a polishing pad. 1) providing a polishing pad including a polishing layer; and
2) polishing the semiconductor substrate while relatively rotating so that the polished surface of the semiconductor substrate is in contact with the polishing surface of the polishing layer;
The polishing layer has a value of 0.6 to 1 according to Equation 1 below.
A method of manufacturing a semiconductor device:
[Equation 1]

Wherein H is the surface hardness of the polishing surface of the polishing layer (shore D),
The M is the elastic modulus of the polishing layer (N/mm ² ),
E is the elongation (%) of the polishing layer. 10. The method of claim 9,
The polishing layer has a value of 0.6 to 1 according to Equation 2 below.
A method of manufacturing a semiconductor device:
[Equation 2]

here,
H, M and E are the same as in claim 9.

Images