KR102206485B1 - Polishing pad and preparation method of semiconductor device using same - Google Patents

Abstract

An embodiment relates to a polishing pad, used for a chemical and mechanical planarization process of a semiconductor device. The polishing pad comprises a laminate composed of a polishing layer, an adhesive layer, and a cushion layer. Initial load resistance (LR) defined by a formula 1 (LR(%)=T1-T2/T1-T3*100) of the laminate is at least 88%. The purpose of the present invention is to provide the polishing pad with excellent polishing characteristics.

Description

Polishing pad and manufacturing method of semiconductor device using the same {POLISHING PAD AND PREPARATION METHOD OF SEMICONDUCTOR DEVICE USING SAME}

Embodiments relate to a polishing pad used in a chemical mechanical planarization (CMP) process of a semiconductor device.

Recently, the semiconductor market is widening, and the use of chemical and mechanical polishing pads is also increasing. The chemical mechanical polishing pad is a polishing pad applied to a chemical mechanical polishing (CMP) process that chemically polishes the surface of a semiconductor substrate such as a wafer, and is one of the important process factors that determine the resulting surface properties of a semiconductor substrate.

In the semiconductor manufacturing process, in the chemical mechanical planarization (CMP) process, a semiconductor substrate is attached to the head and a slurry is supplied to the surface of the semiconductor substrate in contact with the surface of the polishing pad formed on the platen. This is a process of mechanically flattening the irregularities on the surface of the semiconductor substrate by chemically reacting the platen and the head.

During this CMP process, the semiconductor substrate is polished in a state pressed against the surface of the polishing pad at a predetermined pressure, and a polishing slurry is also applied and polished in a wet environment. Therefore, among the various factors that determine the surface characteristics of a semiconductor substrate, the compression characteristics and wetting characteristics of the polishing pad are one of very important factors.

Accordingly, research to improve the polishing characteristics of the CMP process by controlling physical properties related to the compression and wetting characteristics of the polishing layer, cushion layer, and laminate is continuously required.

Korean Patent Publication No. 1107842

An embodiment is to provide a polishing pad having excellent polishing properties such as polishing rate and polishing flatness for tungsten.

A polishing pad according to an embodiment includes a laminate comprising a polishing layer, an adhesive layer, and a cushion layer, and the initial load resistivity (LR) defined by Equation 1 below of the laminate is 88% or more.

X 100<Equation 1> LR (%) =

X 100

In Equation 1 above,

T1 is the thickness of the laminate under no load,

T2 is the thickness of the laminate when the stress load of 30 kPa is maintained for 60 seconds from the no-load state,

T3 means the thickness of the laminate when the stress load of 50 kPa is maintained for 60 seconds from the T2 state.

According to another embodiment, a method of manufacturing a semiconductor device includes preparing a polishing pad including a laminate comprising a polishing layer, an adhesive layer, and a cushion layer; Polishing the surface of the wafer while relatively rotating so that the surface of the wafer is in contact with the polishing layer surface of the polishing pad, and the initial load resistivity (LR) defined by Equation 1 of the laminate is 88% or more to be.

The polishing pad according to the embodiment may secure excellent polishing rate and polishing flatness by controlling physical properties such as resistance characteristics and compressive elastic characteristics of the cushion layer and the laminate.

Therefore, if the polishing pad according to the embodiment is used, the occurrence of defects such as scratches on the object to be polished can be reduced, polishing precision can be improved by suppressing non-uniform polishing, and a semiconductor material of high quality can be provided.

1 is a schematic flowchart of a semiconductor device manufacturing process according to an embodiment.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those of ordinary skill in the art can easily implement them. However, the implementation may be implemented in a variety of different forms and is not limited to the implementation described herein.

In the present specification, when a part "includes" a certain component, it means that other components may be further included rather than excluding other components unless otherwise stated.

In the present specification, the singular expression is interpreted as meaning including the singular or plural, interpreted in context, unless otherwise specified.

In addition, all numbers and expressions representing amounts of components, reaction conditions, and the like described in the present specification are to be understood as being modified by the term "about" in all cases unless otherwise specified.

< Polishing pad >

The embodiment provides a polishing pad having excellent polishing properties such as polishing rate and polishing flatness for tungsten.

A polishing pad according to an embodiment includes a laminate comprising a polishing layer, an adhesive layer, and a cushion layer, and the initial load resistivity (LR) defined by Equation 1 below of the laminate is 88% or more.

X 100<Equation 1> LR (%) =

X 100

In Equation 1 above,

T1 is the thickness of the laminate under no load,

T2 is the thickness of the laminate when the stress load of 30 kPa is maintained for 60 seconds from the no-load state,

T3 means the thickness of the laminate when the stress load of 50 kPa is maintained for 60 seconds from the T2 state.

Specifically, the initial load resistivity (LR) of the laminate is 88.5% or more, 89% or more, 89.5% or more, 90% or more, 90.5% or more, 91% or more, 88% to 98%, 88% to 97%, It may be 88% to 96%, 90% to 98%, or 91% to 97%, but is not limited thereto.

The initial load resistivity (LR) is a value representing the ratio of the degree of change in thickness of the laminate when a weak force and a strong force are applied as a parameter.

A polishing pad to which a laminate having an initial load resistivity (LR) satisfying the above-described range is applied may have a supporting force capable of securing excellent polishing performance while minimizing scratches occurring on the object to be polished.

If a polishing pad using a laminate having an initial load resistivity (LR) outside the above-described range may cause scratches on the object to be polished, the quality of the object to be polished may deteriorate, or polishing performance such as polishing rate or polishing flatness may deteriorate. have.

That is, since the initial load resistivity (LR) of the laminate satisfies the above-described range, in the case of the manufactured polishing pad, it is possible to minimize scratches generated on the object to be polished, as well as excellent polishing rate and polishing flatness, It is easy to planarize materials requiring high surface flatness, such as silicon wafers for semiconductor devices.

The laminate included in the polishing pad according to another embodiment has a compressive modulus (CE) of 50% or more, defined by Equation 2 below.

X 100<Equation 2> CE (%) =

X 100

In Equation 2 above,

T2 is the thickness of the laminate when the stress load of 30 kPa is maintained for 60 seconds from the no-load state,

T3 is the thickness of the laminate when the stress load of 50 kPa is maintained for 60 seconds from the T2 state,

T4 means the thickness of the laminate when the stress load is removed from the T3 state and left for 60 seconds, and then the stress load of 30 kPa is maintained for 60 seconds.

Specifically, the compressive modulus (CE) of the laminate is 55% or more, 58% or more, 60% or more, 63% or more, 65% or more, 68% or more, 70% or more, 50% to 98%, 60% to It may be 98%, 65% to 98%, 70% to 98%, 60% to 95%, 70% to 95%, or 70% to 92%, but is not limited thereto.

The compressive modulus (CE) is a parameter value related to a degree of recovery after applying a strong force to a laminate composed of a polishing layer, an adhesive layer, and a cushion layer for a predetermined time.

A polishing pad to which a laminate having a compressive elastic modulus (CE) satisfying the above-described range is applied can minimize scratches generated on the object to be polished, and can secure a polishing performance of a certain level or higher even after long use.

If a polishing pad using a cushion layer having a compressive modulus (CE) out of the above-described range is used for a long time, the polishing performance may be sharply deteriorated and the polishing performance may not be constant. Alternatively, scratches may occur on the object to be polished and the quality of the object to be polished may deteriorate.

That is, in the case of a polishing pad in which the compressive modulus (CE) of the laminate satisfies the above-described range, the occurrence of defects such as scratches on the object to be polished can be minimized, the polishing performance is kept constant, and excellent polishing rate and polishing flatness Can be secured.

The initial load resistivity (LR) and compressive modulus (CE) of the laminate are not only the material and composition of the laminate, but also the mechanical properties, physical structures, and manufacturing of the polishing layer, adhesive layer, and cushion layer included in the laminate. It can be designed by comprehensively controlling process conditions, post-processing conditions, and storage/aging conditions.

The polishing pad according to the embodiment includes a laminate, and the laminate includes a polishing layer, an adhesive layer, and a cushion layer.

The polishing layer is polished by facing the semiconductor substrate in the polishing process.

The polishing layer may include a urethane-based polymer. The urethane-based polymer may be formed by a curing reaction between a urethane-based prepolymer and a curing agent. Specifically, the polishing layer may include a cured product of a composition including a urethane-based prepolymer, a curing agent, and a foaming agent, but is not limited thereto.

The prepolymer generally refers to a polymer having a relatively low molecular weight in which the degree of polymerization is stopped in an intermediate step to facilitate molding of the final product. These prepolymers can be molded as such or after reaction with other polymerizable compounds.

Specifically, the urethane-based prepolymer includes a prepolymerization reaction product of at least one isocyanate compound and at least one polyol. In addition, the urethane-based prepolymer is prepared by reacting an isocyanate compound and a polyol, and may include an unreacted isocyanate group (NCO). The isocyanate compound and polyol compound are not particularly limited as long as they can be used in the production of urethane-based polymers.

Isocyanate compounds used in the preparation of the prepolymer are toluene diisocyanate (TDI), naphthalene-1,5-diisocyanate (naphthalene-1,5-diisocyanate), paraphenylene diisocyanate (p-phenylene diisocyanate), Toridine diisocyanate, 4,4'-diphenyl methane diisocyanate, hexamethylene diisocyanate (HDI), dicyclohexylmethane diisocyanate ), methylene diphenyl diisocyanate (MDI), 1-isocyanato-4-[(4-isocyanatocyclohexyl)methyl]cyclohexane (1-isocyanato-4-[(4- It may be one or more isocyanates selected from the group consisting of isocyanatocyclohexyl)methyl]cyclohexan, H12MDI) and isoporone diisocyanate, but is not limited thereto.

In addition, the polyol used in the preparation of the prepolymer refers to a compound having two or more hydroxyl groups, and may include a polymer polyol and a monomolecular polyol.

The high molecular weight polyol is, for example, selected from the group consisting of polyether polyol, polyester polyol, polycarbonate polyol, and polycaprolactone polyol. It may be one or more polyols. The high molecular weight polyol may have a weight average molecular weight (Mw) of 300 to 3,000 g/mol.

In addition, examples of the monomolecular polyol include one selected from the group consisting of ethylene glycol (EG), diethylene glycol (DEG), propylene glycol (PG), propanediol (PDO), and methylpropanediol (MP-diol). It may be above, but is not limited thereto.

The urethane-based prepolymer may have an isocyanate end group content (NCO%) of 6 wt% to 12 wt%, 6 wt% to 11 wt%, 6 wt% to 10 wt%, or 8 wt% to 10 wt%.

The urethane-based prepolymer may have a weight average molecular weight (Mw) in the range of 300 to 3,000 g/mol, 500 to 2,500 g/mol, or 700 to 2,000 g/mol.

The curing agent may be at least one selected from the group consisting of an amine compound and an alcohol compound. Specifically, the curing agent may include one or more compounds selected from the group consisting of aromatic amines, aliphatic amines, aromatic alcohols, and aliphatic alcohols.

For example, the curing agent is 4,4'-methylenebis (2-chloroaniline) (MOCA), diethyltoluenediamine (DETDA), bis (4-amino-3-chlorophenyl) methane (bis (4 -amino-3-chlorophenyl)methane, diaminodiphenyl methane, diaminodiphenyl sulphone, m-xylylene diamine, isophorone diamine, ethylene Diamine, diethylenetriamine, triethylenetetramine, polypropylenediamine, polypropylenetriamine, ethylene glycol, diethyleneglycol , Dipropyleneglycol, butanediol, hexanediol, glycerin, and trimethylolpropane. It may be at least one selected from the group consisting of.

The foaming agent is not particularly limited as long as it is commonly used to form pores of the polishing pad. For example, the foaming agent may be at least one selected from a solid foaming agent having a hollow structure, a liquid foaming agent using a volatile liquid, and a gaseous foaming agent such as an inert gas. Specifically, the foaming agent may be one or more selected from the group consisting of a solid foaming agent and a gaseous foaming agent, but is not limited thereto.

The solid foaming agent may be a microcapsule whose size is adjusted by thermal expansion (hereinafter, referred to as'thermal-expanded microcapsules'). The thermally expanded microcapsules may be obtained by heating and expanding the thermally expandable microcapsules. The thermally expanded microcapsules have an advantage of being able to uniformly adjust the particle size of pores by having a particle diameter of a uniform size as a structure of an already expanded microballoon. Specifically, the solid foaming agent may be a micro balloon structure having an average particle diameter of 5 μm to 200 μm.

The thermally expandable microcapsules include an outer shell comprising a thermoplastic resin; And it may include a foaming agent enclosed in the inner shell. The thermoplastic resin may be at least one selected from the group consisting of vinylidene chloride-based copolymers, acrylonitrile-based copolymers, methacrylonitrile-based copolymers, and acrylic copolymers. Furthermore, the blowing agent may be at least one selected from the group consisting of hydrocarbons having 1 to 7 carbon atoms.

The solid foaming agent may be used in an amount of 0.1 parts by weight to 3.0 parts by weight based on 100 parts by weight of the urethane-based prepolymer. Specifically, the solid foaming agent may be used in an amount of 0.5 parts by weight to 2.5 parts by weight, or 0.8 parts by weight to 2.2 parts by weight based on 100 parts by weight of the urethane-based prepolymer.

The gaseous blowing agent may contain an inert gas, and 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 epoxy curing agent. For example, the inert gas may be at least one selected from the group consisting of nitrogen gas (N ₂ ), carbon dioxide gas (CO ₂ ), argon gas (Ar), and helium (He). Specifically, the inert gas may be nitrogen gas (N ₂ ) or carbon dioxide gas (CO ₂ ).

The inert gas may be introduced in a volume corresponding to 10% to 30% of the total volume of the composition. Specifically, the inert gas may be introduced in a volume corresponding to 15% to 30% of the total volume of the composition.

The composition may optionally further include a surfactant.

The surfactant may serve to prevent overlapping and coalescence of formed pores. Specifically, a silicone-based nonionic surfactant is suitable as the surfactant, but may be variously selected according to physical properties required for the polishing pad.

As the silicone-based nonionic surfactant, a silicone-based nonionic surfactant having a hydroxyl group may be used alone or together with a silicone-based nonionic surfactant having no hydroxyl group.

The silicone-based nonionic surfactant having a hydroxyl group is not particularly limited as long as it has excellent compatibility with an isocyanate-containing compound and an active hydrogen compound and is widely used in the field of polyurethane technology. The commercially available material of the silicone-based nonionic surfactant having the hydroxyl group is, for example, DOW CORNING 193 (silicone glycol copolymer, liquid; specific gravity at 25°C: 1.07; viscosity at 20°C: 465 mm 2 /s) ; Flash point: 92°C) (hereinafter referred to as DC-193) and the like.

A commercially available material of the silicone-based nonionic surfactant having no hydroxyl group is, for example, DOW CORNING 190 (silicone glycol copolymer, Gardner color number: 2; specific gravity at 25°C: 1.037; viscosity at 25°C: Dow Corning Co., Ltd.) 2000 ㎟/s; Flash point: 63℃ or higher; Inverse solubility point (1.0% water solution): 36℃) (hereinafter referred to as DC-190).

The surfactant may be included in an amount of 0.1 parts by weight to 2.0 parts by weight based on 100 parts by weight of the urethane-based prepolymer. Specifically, the surfactant may be included in an amount of 0.2 parts by weight to 1.5 parts by weight based on 100 parts by weight of the urethane-based prepolymer. When the surfactant is included in an amount within the above range, pores derived from a gaseous blowing agent can be stably formed and maintained in the mold.

The thickness of the polishing layer is not particularly limited. Specifically, the average thickness of the polishing layer may be 0.5 mm to 4.0 mm, 1.0 mm to 4.0 mm, 1.0 mm to 3.0 mm, 1.5 mm to 3.0 mm, 1.7 mm to 2.7 mm, or 2.0 mm to 3.5 mm.

The hardness of the polishing layer may be 30 Shore D to 80 Shore D. Specifically, the hardness of the polishing layer is 40 Shore D to 80 Shore D, 50 Shore D to 80 Shore D, 40 Shore D to 70 Shore D, 50 Shore D to 70 Shore D, or 55 Shore D to 65 Shore D. However, it is not limited thereto.

The polishing layer may include a plurality of pores. At this time, the average pore size is 5 μm to 50 μm. Specifically, the average size of the pores may be 5 µm to 40 µm, 10 µm to 40 µm, or 10 µm to 30 µm, but is not limited thereto.

The cushioning layer serves to absorb and disperse the impact applied to the polishing layer while supporting the polishing layer.

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

In one embodiment, the cushion layer may be a resin-impregnated nonwoven fabric. The nonwoven fabric may be a fibrous 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. , Polyester-based elastomer resin, polyamide-based elastomer resin, and may include one selected from the group consisting of a combination thereof.

The thickness of the cushion layer is 0.5 to 2.5 mm. Specifically, the thickness of the cushion layer may be 0.8 to 2.5 mm, 1.0 to 2.5 mm, 1.0 to 2.0 mm, 1.2 to 1.8 mm, 1.2 to 1.5 mm, or 1.2 to 1.4 mm, but is not limited thereto.

The hardness of the cushion layer may be 68 to 74 Asker C, 69 to 74 Asker C, 70 to 74 Asker C, or 71 to 74 Asker C, but is not limited thereto.

The density of the cushioning layer may be from about 0.1 g/cm 3 to about 0.6 g/cm 3, for example, from about 0.1 g/cm 3 to about 0.5 g/cm 3, and for example, from about 0.1 g/cm 3 to It may be about 0.4 g/cm 3, and may be, for example, about 0.2 g/cm 3 to about 0.4 g/cm 3.

For the cushion layer, the initial thickness (D1) was measured, the thickness (D2) after pressing for 3 minutes with a weight of 800 g was measured, and the thickness (D3) after having a restoration time of 1 minute was measured. In this case, the compressibility of the cushion layer may be from about 5% to about 15%, and, for example, from about 8% to about 14%, and, for example, from about 10% to about 15%. May be 14%.

<Equation 3> Compression rate (%) = (D1-D2)/D1 X 100

For the cushion layer, the initial thickness (D1) was measured, the thickness (D4) after pressing for 1 minute with a weight of 800 g was measured, and the thickness (D5) after having a restoration time of 1 minute was measured. At this time, the elastic modulus of the cushion layer derived by Equation 4 below may be about 91% or less, for example, about 65% to about 91%, and for example, about 70% to about 91%. And, for example, may be about 80% to about 90%.

<Equation 4> Elastic modulus (%) = (D5-D4)/(D1-D4) X 100

While the laminate satisfies the initial load resistivity according to the <Equation 1> and the compressive elastic modulus according to the <Equation 2> within the above-described range, at the same time, the cushion layer is When the elastic modulus is satisfied within the above-described range, a desired polishing performance may be achieved by laminating the polishing layer together with it. The initial load resistivity, compressive modulus, compressive modulus and modulus of elasticity are designed by comprehensively controlling not only the material and composition of the cushion layer and the laminate, but also the manufacturing process conditions, post-processing conditions, and storage/aging conditions of the cushion layer. I can.

The laminate included in the polishing pad according to the embodiment may include a polishing layer, an adhesive layer, and a cushion layer, and the adhesive layer may be positioned between the polishing layer and the cushion layer.

In addition, the adhesive layer may include a hot melt adhesive.

The hot melt adhesive may be at least one selected from the group consisting of a polyurethane-based resin, a polyester-based resin, an ethylene-vinyl acetate-based resin, a polyamide-based resin, and a polyolefin-based resin. Specifically, the hot melt adhesive may be one or more selected from the group consisting of polyurethane-based resins and polyester-based resins.

The elastic modulus of the polishing pad according to the embodiment may be 100 to 160 kgf/cm ² . Specifically, the elastic modulus of the polishing pad may be 100 to 150 kgf/cm ² , 100 to 140 kgf/cm ² , or 100 to 130 kgf/cm ² , but is not limited thereto.

When the modulus is within the above range, it is possible to provide a polishing pad capable of implementing high polishing planarization characteristics and uniformity while having a high polishing rate.

In addition, the polishing pad according to the embodiment includes a laminate comprising a polishing layer, an adhesive layer, and a cushion layer, and the laminate satisfies the initial load resistivity (LR) and compressive modulus (CE) in the above-described ranges.

The polishing pad according to the embodiment may secure excellent polishing rate and polishing flatness by controlling the initial load resistivity (LR) and compressive elastic modulus (CE) of the laminate to the above-described range levels.

The thickness (T1) in the no-load state of the laminate is 2.0 to 4.5 mm. Specifically, the thickness (T1) of the laminate in the no-load state may be 2.0 to 4.2 mm, 2.5 to 4.2 mm, 2.8 to 4.2 mm, 3.0 to 4.0 mm, 3.2 to 3.8 mm, or 3.2 to 3.6 mm. It is not limited.

The polishing pad according to the embodiment may have a polishing rate of 3840 Å/min or less with respect to tungsten (W). The polishing rate (Å/min) can be obtained by dividing the polishing thickness (Å) of the silicon wafer by the polishing time (minute).

Specifically, the polishing rate of the polishing pad for tungsten (W) is 100 Å/min to 3840 Å/min, 200 Å/min to 3840 Å/min, 500 Å/min to 3840 Å/min, 700 Å/min. To 3840 Å/min, 1000 Å/min to 3840 Å/min, 1500 Å/min to 3840 Å/min, 2000 Å/min to 3840 Å/min, or 2500 Å/min to 3840 Å/min, It is not limited.

When the polishing rate of the polishing pad is out of the above range, defects such as scratches may occur in the object to be polished or polishing performance may be degraded.

Further, the polishing pad according to the embodiment may have a polishing flatness (WIWNU) of 4.3% or less with respect to tungsten (W). The polishing flatness can be obtained through the following equation.

Polishing flatness (%) = (standard deviation of polished thickness (Å)/average polishing thickness (Å)) X 100

Specifically, the polishing flatness (WIWNU) of the polishing pad with respect to tungsten (W) may be 5.5% or less, 4.2% or less, 4.1% or less, 4.0% or less, or 3.9% or less, but is not limited thereto.

When the polishing flatness of the polishing pad is within the above range, it is possible to provide a semiconductor material of excellent quality and easy to flatten the surface of the object to be polished requiring high surface flatness.

The characteristics of the components and properties of the polishing pad described above may be combined with each other.

< Polishing pad Manufacturing method>

A method of manufacturing a polishing pad according to an embodiment includes preparing a composition by sequentially or simultaneously mixing a urethane-based prepolymer, a curing agent, and a foaming agent; And injecting and curing the composition into a mold to form a polishing layer.

The urethane-based prepolymer may include a prepolymerization reaction product of at least one isocyanate compound and at least one polyol. The description of the isocyanate compound and the polyol is as described above.

In addition, if necessary, an additive including a surfactant may be further added to the composition. Description of the surfactant is as described above.

As an example, the urethane-based prepolymer, the curing agent, and the foaming agent may be introduced into the mixing process substantially at the same time, and when the foaming agent, surfactant, and inert gas are further added, these may also be introduced into the mixing process substantially at the same time. .

As another example, a urethane-based prepolymer, a foaming agent, and a surfactant may be premixed, and then a curing agent may be added, or a curing agent and an inert gas may be added together.

The mixing may be performed at a speed of 1,000 to 10,000 rpm, or 4,000 to 7,000 rpm. In the above speed range, it may be more advantageous that the inert gas and the blowing agent are evenly dispersed in the composition.

In addition, the step of preparing the composition may be performed under conditions of 50°C to 150°C, and if necessary, may be performed under vacuum defoaming conditions.

The step of forming the polishing layer by injecting the composition into a mold and curing may be performed under a temperature condition of 60°C to 150°C and a pressure condition of 50 kg/m ² to 260 kg/m ² .

In addition, the manufacturing method may further include a step of cutting the surface of the obtained polishing pad, a step of processing a groove on the surface, an adhesion step with a cushion layer, an inspection step, a packaging step, and the like. These processes can be performed in the manner of a conventional polishing pad manufacturing method.

The description of the polishing pad manufactured according to the above-described manufacturing method is as described above.

Since the polishing pad is manufactured according to the above-described manufacturing method, it may exhibit excellent performance in terms of polishing rate and polishing flatness. In addition, defects such as scratches on the object to be polished can be minimized, the polishing performance can be kept constant, and the life of the polishing pad can be increased. Accordingly, it is possible to provide a semiconductor material such as a semiconductor substrate of excellent quality which is easy to planarize a material requiring high surface flatness, such as a silicon wafer for semiconductor devices.

<Method of manufacturing semiconductor device>

A method of manufacturing a semiconductor device according to an embodiment includes polishing a surface of a semiconductor substrate using a polishing pad according to the embodiment.

Specifically, a method of manufacturing a semiconductor device according to an embodiment includes: preparing a polishing pad including a laminate consisting of a polishing layer, an adhesive layer, and a cushion layer; Polishing the surface of the wafer while relatively rotating so that the surface of the wafer is in contact with the polishing layer surface of the polishing pad, and the initial load resistivity (LR) defined by the following Equation 1 of the laminate is 88% or more to be:

X 100<Equation 1> LR (%) =

X 100

In Equation 1 above,

T1 is the thickness of the laminate under no load,

T2 is the thickness of the laminate when the stress load of 30 kPa is maintained for 60 seconds from the no-load state,

T3 means the thickness of the laminate when the stress load of 50 kPa is maintained for 60 seconds from the T2 state.

1 is a schematic flowchart of a semiconductor device manufacturing process according to an embodiment. Referring to FIG. 1, after mounting the polishing pad 110 according to the embodiment on the base 120, the semiconductor substrate 130 is disposed on the polishing pad 110. In this case, the 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, about 50 cm 3 /min to about It may be 500 cm 3 /min, but is not limited thereto.

Thereafter, the semiconductor substrate 130 and the polishing pad 110 may rotate 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 the same or opposite directions. The rotational speed of the semiconductor substrate 130 and the polishing pad 110 may be selected according to the purpose in the range of about 10 rpm to about 500 rpm, for example, it may be about 30 rpm to about 200 rpm. It is not limited.

The semiconductor substrate 130 may be pressed and brought into contact with the polishing surface of the polishing pad 110 while being mounted on the polishing head 160 with a predetermined load, and then the surface thereof 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 from about 1 gf/cm 2 to about 1,000 gf/cm 2 according to the purpose. And, for example, it may be 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 polishing through the conditioner 270 simultaneously with the polishing of the semiconductor substrate 130 It may further include processing the polishing surface of the pad 110.

The polishing pad according to the embodiment can improve the polishing rate and polishing flatness by controlling the initial load resistivity (LR) of the laminate, so that a semiconductor device of excellent quality is efficiently manufactured using the polishing pad. can do.

The above will be described in more detail by the following examples. However, the following examples are for illustrative purposes only, and the scope of the examples is not limited thereto.

< Example >

Example One

1-1: Device configuration

In a casting equipment equipped with a urethane-based prepolymer, a curing agent, an inert gas injection line, and a reaction rate control agent injection line, a prepolymer composition (SKC) having an unreacted NCO of 9.1% by weight was filled in the prepolymer tank, and bis(4) was added to the curing agent tank. -Amino-3-chlorophenyl) methane (bis (4-amino-3-chlorophenyl) methane, Ishihara company) was charged, and nitrogen (N ₂ ) was prepared as an inert gas. In addition, 1 part by weight of a solid foaming agent (manufactured by Akzonobel) and 1 part by weight of a silicone-based surfactant (Evonik) were mixed in advance with respect to 100 parts by weight of the urethane-based prepolymer, and then injected into the prepolymer tank.

1-2: Preparation of polishing pad

The raw materials were stirred while being added to the mixing head at a constant speed through each input line. At this time, the prepolymer and the curing agent were added in an equivalent ratio of 1:1. Nitrogen (N ₂ ), an inert gas, was added at a rate of 1 L/min. The stirred raw material was discharged to a mold (1,000 mm x 1,000 mm x 3 mm) preheated to 120°C, but was injected at a discharge rate of 10 kg/min and then cast at 120°C to obtain a molded body. Thereafter, the upper and lower ends of the molded body were cut each 0.5 mm thick to obtain a polishing layer having a thickness of 2 mm.

In addition, as a cushion layer impregnated with a polyurethane resin in a polyester fiber nonwoven fabric, among them, a cushion layer having the hardness shown in Table 1 is selected, and the polishing layer and the cushion layer are attached using a hot melt adhesive, and the following Table 1 A polishing pad comprising a laminate having the thickness, initial load resistivity and compressive modulus described in was prepared.

Example 2

In Example 1, the stirred raw material was discharged to a mold (1,000 mm x 1,000 mm x 3 mm) preheated at 80° C., but injected at a discharge rate of 10 kg/min, and then cast at 120° C. to form a molded article. The obtained and the cushion layer having the hardness shown in Table 1 below was selected and prepared, and the polishing layer and the cushion layer were adhered using a hot melt adhesive to obtain a laminate having the thickness, initial load resistivity and compressive elasticity shown in Table 1 below. A polishing pad was manufactured in the same manner, except that the polishing pad including was manufactured.

Example 3

In Example 1, a cushion layer having the hardness shown in Table 1 below was selected and prepared, and the polishing layer and the cushion layer were attached using a hot melt adhesive to have the thickness, initial load resistivity, and compressive modulus shown in Table 1 below. A polishing pad was manufactured in the same manner, except that a polishing pad including a laminate was manufactured.

Example 4

2-1: Device configuration

In the casting equipment of Example 1, the inert gas injection line was cut off. PUGL-600D having 9.1 NCO% (manufactured by SKC, weight average molecular weight: 1,500 g/mol) was filled in a prepolymer tank, and 4,4'-methylenebis(2-chloroaniline) (TCI (Tokyo Chemical Industry) company product) was filled. Further, 2 parts by weight of a solid foaming agent (Akzonobel) was premixed with respect to 100 parts by weight of the urethane-based prepolymer, and then injected into the prepolymer tank.

2-2: Preparation of polishing pad

The raw materials were stirred while being added to the mixing head at a constant speed through each input line. At this time, the prepolymer and the curing agent were added in an equivalent ratio of 1:1. The stirred raw material was discharged to a mold (1,000 mm x 1,000 mm x 3 mm) preheated to 120°C, but was injected at a discharge rate of 10 kg/min and then cast at 120°C to obtain a molded body. Thereafter, the upper and lower ends of the molded body were cut each 0.5 mm thick to obtain a polishing layer having a thickness of 2 mm.

In addition, as a cushion layer impregnated with a polyurethane resin in a polyester fiber nonwoven fabric, a cushion layer having a hardness as shown in Table 1 below is selected and prepared, and the polishing layer and the cushion layer are attached using a hot melt adhesive. A polishing pad including a laminate having the thickness, initial load resistivity, and compressive modulus shown in Table 1 was prepared.

Example 5

In Example 4, the stirred raw material was discharged to a mold (1,000 mm x 1,000 mm x 3 mm) preheated at 80°C, but injected at a discharge rate of 10 kg/min and then cast at 120°C to form a molded body. Including a laminate having the thickness, initial load resistivity and compressive elastic modulus as shown in Table 1 by selecting and preparing the obtained cushion layer and the cushion layer having the hardness shown in Table 1 below, and attaching the polishing layer and the cushion layer using a hot melt adhesive A polishing pad was manufactured in the same manner, except that the polishing pad was manufactured.

Example 6

In Example 4, a cushion layer having hardness as shown in Table 1 below was selected and prepared, and the polishing layer and the cushion layer were attached using a hot melt adhesive to have the thickness, initial load resistivity, and compressive modulus as shown in Table 1 below. A polishing pad was manufactured in the same manner, except that a polishing pad including a laminate was manufactured.

Comparative example One

In Example 1, a cushion layer having the hardness shown in Table 1 below was selected and prepared, and the polishing layer and the cushion layer were attached using a hot melt adhesive to have the thickness, initial load resistivity, and compressive modulus shown in Table 1 below. A polishing pad was manufactured in the same manner, except that a polishing pad including a laminate was manufactured.

Comparative example 2

In Example 4, a cushion layer having hardness as shown in Table 1 below was selected and prepared, and the polishing layer and the cushion layer were attached using a hot melt adhesive to have the thickness, initial load resistivity, and compressive modulus as shown in Table 1 below. A polishing pad was manufactured in the same manner, except that a polishing pad including a laminate was manufactured.

< Evaluation example >

The following physical properties were measured and evaluated for the polishing pads prepared in Examples 1 to 6 and Comparative Examples 1 and 2, and the results are shown in Table 1 below.

Evaluation example 1: hardness

The cushion layer sample was cut into 5 cm Х 5 cm (thickness: described in Table 1), and after storage at 25° C. for 12 hours, Asker C hardness was measured using a hardness tester.

Evaluation example 2: Initial load resistivity ( % )

The laminate sample was cut into 5 cm Х 5 cm (thickness: described in Table 1), and the thickness of the laminate in the no-load state was measured, and this was referred to as T1 (mm), and the stress load of 30 kPa from the no-load state was 60 The thickness of the laminate when held for a second is measured, and this is called T2 (mm), and the thickness of the laminate is measured when the stress load of 50 kPa is maintained for 60 seconds from the T2 state and this is T3 (mm). After d, the initial load resistivity was calculated according to Equation 1 below.

X 100<Equation 1> LR (%) =

X 100

Evaluation example 3: Compression modulus ( % )

The laminate sample was cut into 5 cm Х 5 cm (thickness: described in Table 1), and the thickness of the laminate was measured when the stress load of 30 kPa was maintained for 60 seconds from the no-load state, and this was T2 (mm). And, by measuring the thickness of the laminate when the stress load of 50 kPa is maintained for 60 seconds from the T2 state, this is referred to as T3 (mm), and after removing the stress load from the T3 state and leaving it for 60 seconds, The thickness of the laminate when the stress load of 30 kPa (300 g/cm ² ) was maintained for 60 seconds was measured and referred to as T4 (mm), and the compressive modulus was calculated according to Equation 2 below.

X 100<Equation 2> CE (%) =

X 100

Evaluation example 4: elastic Modulus

The polishing pad sample is cut into 4 cm x 1 cm (thickness: described in Table 1), and when the elongation is 70% and the elongation is 20% at a speed of 50 mm/min using a universal testing system (UTM). The modulus was measured by indicating the slope of which the lines of were connected.

Evaluation example 5: polishing rate

A silicon wafer having a diameter of 300 mm on which a tungsten (W) film was formed by a CVD process was installed using a CMP polishing equipment. Thereafter, a tungsten (W) film of a silicon wafer was set down on the surface plate to which the polishing pad was attached. Thereafter, the polishing load was adjusted to be 2.8 psi, and the calcined silica slurry was introduced onto the polishing pad at a rate of 190 ml/min, while the platen was rotated at 115 rpm for 30 seconds to polish the tungsten (W) film. After polishing, the silicon wafer was removed from the carrier, mounted on a spin dryer, washed with purified water (DIW), and dried with air for 15 seconds. The thickness difference before and after polishing was measured on the dried silicon wafer using a contact type sheet resistance measuring device (4 point probe). Then, the polishing rate was calculated using the above equation.

Polishing rate (Å/min) = polishing thickness of silicon wafer (Å) / polishing time (minute)

Evaluation example 6: polishing flatness

After 1 minute of polishing under the above-described polishing conditions using a 1 µm (10,000 Å) thermal oxide film of a silicon wafer on which a tungsten (W) film was formed obtained by the same method as the polishing rate measurement, the in-plane film of 98 wafers The thickness was measured and the polishing flatness (WIWNU: Within Wafer Non Uniformity) in the wafer plane was measured using the following equation.

Polishing flatness (%) = (standard deviation of polished thickness (Å)/average polishing thickness (Å)) X 100

division Cushion layer Laminate Elastic modulus Polishing rate Polishing flatness Hardness
(Asker C) thickness
(mm) Initial load resistivity (%) Compression modulus (%) (kgf/cm ² ) W
(Å/min) W
(%) Example 1 71.55 3.413 94.96 83.33 119.3 3724 3.2 Example 2 71.2 3.411 91.80 90.00 130 3324 3.8 Example 3 71.75 3.412 94.74 77.78 105 3806 3.1 Example 4 71.11 3.411 91.13 90.91 125.2 3357 3.4 Example 5 71.32 3.407 94.64 88.89 120.3 3345 3.9 Example 6 73.9 3.405 95.76 71.43 110.5 3797 3.5 Comparative Example 1 74.5 3.416 87.83 28.57 95.2 3842 4.5 Comparative Example 2 74.2 3.419 38.46 46.88 80.4 3905 4.7

As shown in Table 1, it was confirmed that the polishing pads of Examples 1 to 6 had superior polishing rates and flatness compared to the polishing pads of Comparative Examples 1 and 2.

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

Claims (10)

Including a laminate consisting of a polishing layer, an adhesive layer and a cushion layer,
The laminate has an initial load resistivity (LR) of 88% or more, defined by Equation 1 below,
The elastic modulus of the laminate is 100 to 160 kgf/cm ² ,
A polishing pad having a hardness of the cushion layer of 68 to 74 Asker C:
<Equation 1> LR (%) =

X 100
In Equation 1 above,
T1 is the thickness of the laminate under no load,
T2 is the thickness of the laminate when the stress load of 30 kPa is maintained for 60 seconds from the no-load state,
T3 means the thickness of the laminate when the stress load of 50 kPa is maintained for 60 seconds from the T2 state.
The method of claim 1,
A polishing pad having a compressive elastic modulus (CE) of 50% or more as defined by Equation 2 below:
<Equation 2> CE (%) =

X 100
In Equation 2 above,
T2 is the thickness of the laminate when the stress load of 30 kPa is maintained for 60 seconds from the no-load state,
T3 is the thickness of the laminate when the stress load of 50 kPa is maintained for 60 seconds from the T2 state,
T4 means the thickness of the laminate when the stress load is removed from the T3 state and left for 60 seconds, and then the stress load of 30 kPa is maintained for 60 seconds.
delete The method of claim 1,
A polishing pad having a thickness (T1) of 2.0 to 4.5 mm in the no-load state of the laminate.
delete The method of claim 1,
The polishing rate for tungsten (W) is 3840 Å/min or less,
Polishing pad with a polishing flatness (WIWNU) of 4.3% or less for tungsten (W).
The method of claim 1,
The polishing layer comprises a cured product of a composition comprising a urethane-based prepolymer, a curing agent and a foaming agent, and satisfying at least one of the following i), ii) and iii), a polishing pad:
i) the urethane-based prepolymer contains a prepolymerization reaction product of at least one isocyanate compound and at least one polyol;
ii) the curing agent is at least one selected from the group consisting of amine compounds and alcohol compounds;
iii) The foaming agent is at least one selected from the group consisting of a solid foaming agent and a gaseous foaming agent.
The method of claim 1,
The polishing pad, wherein the cushion layer comprises a nonwoven fabric or suede.
The method of claim 1,
The polishing pad, wherein the adhesive layer comprises a hot melt adhesive.
Preparing a polishing pad including a laminate comprising a polishing layer, an adhesive layer, and a cushion layer;
Polishing the surface of the wafer while relatively rotating so that the surface of the wafer contacts the surface of the polishing layer of the polishing pad,
The laminate has an initial load resistivity (LR) of 88% or more, defined by Equation 1 below,
The elastic modulus of the laminate is 100 to 160 kgf/cm ² ,
The method of manufacturing a semiconductor device, wherein the cushion layer has a hardness of 68 to 74 Asker C:
<Equation 1> LR (%) =

X 100
In Equation 1 above,
T1 is the thickness of the laminate under no load,
T2 is the thickness of the laminate when the stress load of 30 kPa is maintained for 60 seconds from the no-load state,
T3 means the thickness of the laminate when the stress load of 50 kPa is maintained for 60 seconds from the T2 state.

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