KR102488112B1 - Polishing pad, manufacturing method thereof and preparing method of semiconductor device using the same - Google Patents

Abstract

The present invention maintains the polishing performance required for the polishing process, such as polishing speed and polishing profile, minimizes defects that may occur on the wafer during the polishing process, and achieves the same level of flatness even when different film qualities are polished simultaneously. Polishing that can be polished to have, and when applying the polishing pad in the CMP process, the polishing pad can be determined to control the optimal polishing selectivity along with the performance in the polishing process through the physical property values of the polishing pad without a direct polishing test A pad and a method for manufacturing the same are provided.

Description

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

In the chemical mechanical planarization (CMP) process of the semiconductor manufacturing process, a wafer is attached to a head and brought into contact with the surface of a polishing pad formed on a platen, and slurry is supplied to chemically polish the wafer surface. It is a process of mechanically flattening the concavo-convex part of the wafer surface by relatively moving the platen and the head while reacting.

In general, in the case of performing the CMP (Chemical Mechanical Polishing) process for forming an element isolation film of a semiconductor device, in order to increase the 'polishing' selectivity of the oxide film and the 'pad' nitride film, the high selectivity of the ceria series with a large difference in 'polishing' speed between the oxide film and the 'pad' nitride film use a slurry However, when a ceria-based abrasive is used, precipitation occurs due to aggregation between particles, and in order to prevent this, there is a problem that a slurry precipitation prevention device capable of preventing precipitation should be used instead of existing equipment.

In addition, in the case of using a ceria-based abrasive, a compound that increases the 'polishing' selectivity between the oxide film and the 'pad' and nitride film is added. There is a problem of reducing the life of the.

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, but even if this device is added, it is difficult to accurately control or maintain the mixing ratio of the abrasive and the additional compound. .

In the case of ceria-based abrasives, 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 step in which only the oxide film is polished, and the oxide film and the “pad” nitride film are A method of using a ceria-based abrasive for the second process of polishing at the same time has been proposed.

However, this method is highly likely to cause defects due to differences in basic characteristics between the slurries, such as aggregation due to a pH difference between the silica-based slurry and the ceria-based abrasive. Since the process has to be performed, there is a problem in that the process is complicated and two pieces of equipment must be used.

As a result, there is a problem that it is not easy to adjust the selectivity depending on the type of abrasive in the slurry. In order to solve this problem, development of a polishing pad capable of exhibiting a high polishing selectivity without being affected by the abrasive contained in the slurry need this

An object of the present invention is to provide a polishing pad and a manufacturing method thereof.

Another object of the present invention is to maintain the polishing performance required for the polishing process, such as polishing speed and polishing profile, to minimize defects that may occur on the wafer during the polishing process, and to achieve an equal level even when film qualities of different materials are simultaneously polished. An object of the present invention is to provide a polishing pad that can be polished to have a flatness of , and a manufacturing method thereof.

Another object of the present invention is to 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 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 for manufacturing a semiconductor device using a polishing pad.

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

[Equation 1]

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

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

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

A method for 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 including the prepolymer composition, a foaming agent, and a curing agent; and iii) preparing an abrasive layer by curing the composition for preparing an abrasive layer, wherein the abrasive layer has a value of 0.6 to 1 according to Equation 1 below:

[Equation 1]

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

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

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

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

[Equation 1]

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

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

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 polishing speed and polishing profile, minimizes defects that may occur on the wafer during the polishing process, and has the same level even when film qualities of different materials are simultaneously polished. When the polishing pad is applied in the CMP process, it is possible to determine the polishing pad to control 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. can

In addition, a method of manufacturing a semiconductor device using the polishing pad 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 skilled in the art can easily implement the present invention. However, the present invention may be embodied in many 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 cases.

Unless otherwise stated herein, all percentages, parts, ratios, etc. are by weight.

In the present invention, when "comprising", this means that other components may be additionally included without excluding other components unless otherwise stated.

As used herein, "plurality" refers to more than one.

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

[Equation 1]

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

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

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 below:

[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 equivalent of curing reactive groups such as an amine group (-NH ₂ ) and an alcohol group (-OH) of the curing agent and an isocyanate group (-NCO) of the prepolymer are determined according to 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 cure rate and the sequential sequence of chemical reactions.

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

In particular, when the value according to Equation 1 according to the hardness, elastic modulus and elongation of the polishing layer of the present invention is 0.6 to 1, the polishing selectivity among the polishing performance of the polishing object containing the oxide film and the nitride film can be particularly controlled.

In general, the polishing selectivity of the nitride layer to the oxide layer should be adjusted to prevent dishing and to minimize defects that may occur on the wafer.

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

In addition, when the polishing selectivity of the nitride layer to the oxide layer is high, the upper layer is excessively removed and recesses occur, and the insulating layer or barrier layer collapses due to the physical action of the abrasive particles (erosion). ) can be intensified.

That is, the polishing pad of the present invention is characterized by achieving surface planarization of a target film quality in a semiconductor substrate by controlling the polishing selectivity with respect to an oxide film and a nitride film within 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 equation, oxide and The polishing selectivity (Ox RR/Nt RR) of the nitride film can be adjusted.

That is, the polishing layer includes a urethane-based prepolymer, and physical/mechanical characteristics of hardness, elastic modulus, and elongation are affected by the curing 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, and the polishing rate for the target film is different due to differences in hardness, elastic modulus, and elongation. will appear

Regarding the polishing rate, as described above, when the target film quality is an oxide layer or a nitride layer, the occurrence of defects can be prevented by finely adjusting the polishing rate for each target film quality.

Among the physical/mechanical properties of the abrasive layer, hardness, elastic modulus and elongation are important factors that affect the polishing rate of the target film. I would say it is feasible.

Therefore, in the present invention, as shown in Equations 1 and 2, weights are given to hardness, elastic modulus, and elongation, and values are specified to adjust the polishing selectivity for oxide and nitride films, thereby exhibiting excellent polishing performance. can

In another embodiment, in the CMP polishing process, application of the polishing pad requires confirmation of whether the polishing selectivity is suitable for the process through a polishing test.

Specifically, it is necessary to confirm the polishing rate for oxide and nitride in the CMP polishing process, and the confirmation of the corresponding polishing rate was possible only through numerical values confirmed through direct polishing tests.

However, like the polishing pad of the present invention, if the values of the hardness, elastic modulus and elongation of the polishing surface are checked, and the values are derived by substituting them into Equation 2 or 3, the oxide and nitride films An estimated value of the polishing selectivity to (Nitride) can be derived, which will allow use of the polishing pad without polishing tests.

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

The polishing selectivity is calculated by measuring the polishing rate of 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, a polishing load of 1.4 psi, and a ceria slurry at a rate of 190 ml / min. The surface plate equipped with the polishing pad was rotated at a speed of 115 rpm, and the silicon oxide film was polished for 60 seconds, and then the thickness was measured and the polishing rate was calculated using the thickness difference before polishing.

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

In one embodiment, the polishing layer may include a polishing 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 is specifically described below.

A 'prepolymer' refers to a polymer having a relatively low molecular weight in which the degree of polymerization is stopped at an intermediate stage so as to facilitate molding in the production of a cured product. The prepolymer may be molded into the final cured product either as such or after reacting with other polymeric 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 diisocyanates, aliphatic diisocyanates, alicyclic diisocyanates, and combinations thereof may be used.

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

'Polyol' refers to a compound containing 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, acryl polyol, and combinations thereof. can 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 , 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 polyol having a weight average molecular weight (Mw) of about 300 g/mol or more and about 1800 g/mol or less. may contain 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-toluene diisocyanate (2,6-TDI) may be included. 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% to about 11% by weight, for example, about 5% to about 10% by weight, for example, about 5% to about 8% by weight , for example, from about 8% to about 10% by weight. When the NCO% is in the above range, the physical properties of the polishing layer in the polishing pad are appropriately displayed, the polishing performance required for the polishing process such as the polishing rate and the polishing profile is maintained, and defects that may occur on the wafer during the polishing process are minimized. can

In addition, by adjusting the polishing selectivity (Ox RR / Nt RR) of oxide and nitride, dishing, recess and erosion are prevented, and surface planarization within the wafer can be achieved.

The isocyanate end group content (NCO%) of the urethane-based prepolymer is the type and content of the isocyanate compound and the 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 adjusting the type and content of additives used in the manufacture of the prepolymer.

The curing agent is a compound for forming a final cured structure in the polishing layer by chemically reacting with the urethane-based prepolymer, 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, fatty amines, aromatic alcohols, fatty 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, Methylene bis-methylanthranilate, diaminodiphenylsulfone, m -xylylenediamine, isophoronediamine, ethylenediamine, diethylenetriamine, triethylenetetramine, polypropylenediamine, polypropylenetriamine (polypropylenetriamine), bis (4-amino-3-chlorophenyl) methane (bis (4-amino-3-chlorophenyl) methane), and combinations thereof.

The content 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 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 combinations 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 gaseous foaming agent, or a combination thereof.

The solid foaming agent has an average particle diameter of about 5 μm to about 200 μm, such as about 20 μm to about 50 μm, such as about 21 μm to about 50 μm, such as 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 a thermally expanded particle 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 particles after being expanded by heat or pressure.

The solid foaming agent may include expandable particles. The expansible particles are particles having characteristics of being expandable by heat or pressure, and the size in the final polishing layer may be determined by heat or pressure applied in the process of manufacturing the polishing layer. The expandable particle may include a thermally expanded particle, an unexpanded particle, or a combination thereof. The thermally expanded particles are particles pre-expanded by heat, and mean 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 particles that are not previously expanded, and mean particles whose final size is determined by being expanded by heat or pressure applied during the manufacturing process of the abrasive layer.

The expandable particle has an outer shell of a resin material; and an expansion-inducing component present inside the envelope sealed.

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

The swelling-causing component may include one selected from the group consisting of hydrocarbon compounds, chlorofluoro compounds, tetraalkylsilane compounds, 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 compounds are trichlorofluoromethane (CCl3F), dichlorodifluoromethane (CCl2F2), chlorotrifluoromethane (CClF3), tetrafluoroethylene (CClF ₂ -CClF ₂ ) and 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 particles treated with an inorganic component. For example, the solid foaming agent may include expandable particles treated with an inorganic component. In one embodiment, the solid foaming agent may include silica (SiO ₂ ) particle-treated expandable particles. Treatment with an inorganic component of the solid foaming agent can prevent aggregation between a plurality of particles. The solid foaming agent treated with an inorganic component may have different chemical, electrical and/or physical properties of the surface of the foaming agent from that of the solid foaming agent not treated with the inorganic component.

The amount of the solid foaming agent is about 0.5 part 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 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 gaseous blowing agent may include an inert gas. The gaseous blowing agent may be added during a reaction between the urethane-based prepolymer and the curing agent and used as a pore-forming element.

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 may be designed according to the desired pore structure and physical properties of the abrasive layer.

In one embodiment, the blowing agent may include a solid blowing agent. For example, the foaming agent may consist only of 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 of only thermally expanded particles. In the case of including only the thermally expanded particles without including the unexpanded particles, the variability of the pore structure is reduced, but the predictability is increased, and it may be advantageous to implement homogeneous pore characteristics over the entire area of the polishing 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, such as about 10 μm to about 80 μm, such as about 20 μm to about 70 μm, such as about 20 μm to about 50 μm. μm, such as from about 30 μm to about 70 μm, such as from about 25 μm to about 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 about 30 kg / m 3 to about 80 kg / m 3, for example, about 35 kg / m 3 to about 80 kg / m 3, for example, about 35 kg / m 3 to about 75 kg / m 3, For example, it may be about 38 kg/m 3 to about 72 kg/m 3 , for example about 40 kg/m 3 to about 75 kg/m 3 , for example about 40 kg/m 3 to about 72 kg/m 3 .

In one embodiment, the blowing agent may include a gaseous blowing agent. For example, the foaming agent may include a solid foaming agent and a gaseous foaming agent. Details regarding the solid foaming agent are as described above.

The gaseous blowing agent may include nitrogen gas.

The gaseous foaming agent may be injected through a predetermined injection line while the urethane-based prepolymer, the solid foaming agent, and the curing agent are mixed. The injection rate of the gaseous blowing agent is about 0.8 L/min to about 2.0 L/min, such as about 0.8 L/min to about 1.8 L/min, such as about 0.8 L/min to about 1.7 L/min. , such as 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 surfactants and reaction rate regulators. The names such as 'surfactant' and 'reaction rate regulator' are arbitrary names based on the main role of the corresponding material, and each corresponding material does not necessarily perform only functions limited to the role with the corresponding name.

The surfactant is not particularly limited as long as it serves to prevent phenomena such as 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. parts by weight, 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 about 1.5 parts by weight. When the surfactant is included in an amount within the above range, pores derived from the gaseous foaming agent may be stably formed and maintained in the mold.

The reaction rate controller plays a role of accelerating or delaying the reaction, and depending on the purpose, a reaction accelerator, a reaction retardant, or both may be used. The reaction rate controller may include a reaction accelerator. For example, the reaction promoter may be at least one reaction promoter selected from the group consisting of tertiary amine-based compounds and organometallic compounds.

Specifically, the reaction rate controller 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-azanovoneine, 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 regulator may include at least one selected from the group consisting of benzyldimethylamine, N,N-dimethylcyclohexylamine, and triethylamine.

The reaction rate regulator 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 regulator 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 from about 0.1 parts by weight to about 1.5 parts by weight, such as from about 0.1 parts by weight to about 0.3 parts by weight, such as from about 0.2 parts by weight to about 1.8 parts by weight, such as 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 Can be used in negative amounts. When the reaction rate controller is used in the above-described content range, the curing reaction rate of the prepolymer composition can be appropriately controlled 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 damaging the polishing target during the polishing process using the polishing pad And the occurrence of defects can be minimized.

The cushion layer may include non-woven 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 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, a polybutadiene resin, a styrene-butadiene copolymer resin, a styrene-butadiene-styrene copolymer resin, an acrylonitrile-butadiene copolymer resin, a styrene-ethylene-butadiene-styrene copolymer resin, and a silicone rubber resin. , A polyester-based elastomer resin, a polyamide-based elastomer resin, and a combination thereof may include one selected from the group consisting of.

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

In another embodiment according to the present invention, preparing a prepolymer composition; preparing a composition for preparing an abrasive layer including the prepolymer composition, a foaming agent, and a curing agent; and preparing a polishing layer by curing the composition for preparing the polishing layer.

Preparing 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 about 5% to about 15% by weight, for example, about 5% to about 8% by weight, for example, about 5% to about 7% by weight, for example, from about 8% to about 15%, such as from about 8% to about 14%, such as from about 8% to about 12%, such as from 8% to It may be about 10% by weight.

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

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

The foaming agent may include a solid foaming agent or a gaseous foaming agent.

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

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

When the foaming agent includes a gaseous 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 preparing a fourth preliminary composition by injecting the gaseous foaming agent into the third 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 includes 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 a 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 about 100 °C to about 130 °C, for example, about 100 °C to about 125 °C, for example, about 100 °C to about 120 °C.

The step of curing the composition for preparing the polishing layer at 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 a polishing layer cured at the first temperature at 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 30 hours. About 30 hours, such as from about 10 hours to about 25 hours, such as from about 12 hours to about 24 hours, such as from about 15 hours to about 24 hours.

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

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

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 radial grooves continuously connected from the center of the polishing layer to the edge of the polishing layer.

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

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

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

The polishing 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, and the heat-sealing adhesive is applied on the surface of the cushion layer to be in contact with the polishing layer. After the polishing layer and the cushion layer are laminated to each other, the two layers may be fused using a pressure roller.

In another embodiment, providing a polishing pad including a polishing layer; and polishing the polishing target while relatively rotating the polishing surface of the polishing target so that the polishing surface of the polishing layer comes into contact with the polishing surface of the polishing layer.

1 illustrates a schematic process diagram of a semiconductor device manufacturing process according to an embodiment. Referring to FIG. 1 , after the polishing pad 110 according to the exemplary embodiment is mounted on a surface plate 120 , a semiconductor substrate 130 to be polished is disposed on the polishing pad 110 . At this time, the surface to be polished of the semiconductor substrate 130 directly contacts the polishing surface of the polishing pad 110 . For polishing, the polishing slurry 150 may be sprayed onto the polishing pad through the nozzle 140 . The flow rate of the abrasive 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 rotate relative to each other, so that the surface of the semiconductor substrate 130 can 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. 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, and may be, for example, about 30 rpm to about 200 rpm, It is not limited thereto.

The semiconductor substrate 130 may be pressed and brought into contact with the polishing surface of the polishing pad 110 with a predetermined load while being mounted on the polishing head 160, 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 from a range of about 1 gf/cm 2 to about 1,000 gf/cm 2 depending on 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 of the semiconductor substrate 130 and the polishing through the conditioner 170 simultaneously. A step of processing the polishing surface of the pad 110 may be further included.

Hereinafter, specific embodiments of the present invention are presented. However, the embodiments described below are only intended to specifically illustrate or explain the present invention, and the present invention should not be limited thereto.

Example 1

Manufacture of polishing pads

In a casting equipment equipped with a mixture injection line of a urethane-based prepolymer, a curing agent, and a solid foaming agent, the urethane-based prepolymer having 9% by weight of unreacted NCO is filled in the prepolymer tank, and bis(4-amino-3-chlorophonyl) is added to the curing agent tank. Methane (bis(4-amino-3-chlorophenyl)methane, manufactured by Ishihara) was filled. 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.

The urethane-based prepolymer and the curing agent were introduced into the mixing head at a constant rate through each input line 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 set to 1:1, and the total input amount was maintained at a rate of 10 kg/min.

The stirred raw material was injected into a preheated mold, and a porous polyurethane sheet was produced. Thereafter, the surface of the prepared porous polyurethane sheet was ground using a grinding machine and grooved using a tip to obtain an average thickness of 2 mm and an average diameter of 76.2 cm.

The polyurethane sheet and suede (substrate 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. 90 parts by weight of toluene diisocyanate and 10 parts by weight of dicyclohexylmethane diisocyanate were mixed with a total of 100 parts by weight of the diisocyanate component. 90 parts by weight of PTMEG (molecular weight (MW) 1,000) and 10 parts by weight of DEG were mixed with 100 parts by weight of the total weight of the polyol component. Each mixed raw material was prepared with 152 parts by weight of the total amount of the polyol compared to 100 parts by weight of the total amount of the diisocyanate. After adding each of the mixed raw materials to a four-necked flask, they were reacted at 80° C. to prepare a preliminary composition having a urethane group. The isocyanate group (NCO group) content in the regular preliminary composition was prepared to be 8.8 to 9.4%.

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

When injecting the stirred raw material 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% curing agent
(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 pads

(1) hardness

1) The Shore D hardness of the polishing pads prepared according to the above Examples and Comparative Examples was measured, and the polishing pads were cut to a size of 2 cm Х 2 cm (thickness: 2 mm) at a temperature of 25 ° C and a humidity of 50 ± 5% was allowed to stand for 16 hours in an environment of Then, the hardness of the polishing pad was measured using a durometer (D-type durometer).

(2) modulus of elasticity

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

(3) Elongation

For each of the polishing pads prepared according to the above Examples and Comparative Examples, the maximum deformation amount immediately before fracture was measured while testing at a speed of 500 mm/min using a universal test system (UTM), and then the ratio of the maximum deformation amount 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 placed. Thereafter, a silicon oxide film of a silicon wafer was set down on a platen to which the polishing pad was attached. Thereafter, the polishing load was adjusted to 1.4 psi, and the silicon oxide film was polished by rotating the platen at 115 rpm for 60 seconds while injecting the polishing slurry (ceria slurry) onto the polishing pad at a rate of 190 ml/min. 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 of the dried silicon wafer was measured using an optical coherence thickness measurement device (manufacturer: Kyence, model name: SI-F80R). Then, the polishing rate was calculated using Equation 1 above.

<Ablation rate for silicon nitride (SiN) film>

Using CMP polishing equipment, a silicon wafer having a diameter of 300 mm on which a SiN film was formed by a CVD process was placed. Thereafter, a SiN film of a silicon wafer was set down on a surface plate to which the polishing pad was attached. Thereafter, the polishing load was adjusted to 1.4 psi, and the SiN film was polished by rotating the platen at 115 rpm for 60 seconds while injecting the polishing slurry (ceria slurry) on the polishing pad at a rate of 190 ml/min. 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 of the dried silicon wafer was measured using an optical coherence type thickness measuring device (manufacturer: Kyence, model name: SI-F80R). Then, the polishing rate was calculated using Equation 1 above.

<Equation 1>

Polishing rate (Å/min) = Thickness difference before and after polishing (Å)/polishing time (minutes)

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, in the case of the polishing pads of Examples 1 to 4, there were some differences in hardness, modulus and elongation compared to the comparative example. In particular, as a result of checking the value according to the equation according to the relationship between the physical properties of the polishing pad, in the case of the embodiment of the present invention, it was confirmed that the value was within a specific range, and when the value was within the range, the polishing speed could be adjusted. Confirmed.

Although the 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 of those skilled in the art using the basic concept of the present invention defined in the following claims are also made according to the present invention. falls within the scope of the rights of

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

Claims (10)

Including an abrasive layer,
The value according to the following formula 1 is 0.6 to 1,
The value according to Equation 2 below is 0.6 to 1,
polishing pad:
[Equation 1]

[Equation 2]

The H is the surface hardness (shore D) of the polished surface of the polishing layer,
The M is the modulus of elasticity (N/mm ² ) of the polishing layer,
E is the elongation (%) of the polishing layer. delete According to claim 1,
The polishing layer has a polishing selectivity (Ox RR / Nt RR) of an oxide film and a nitride film of 25 to 40
polishing pad. According to claim 1,
The surface hardness of the abrasive layer at 25 ° C on the polished surface is 45 to 65 shore D
polishing pad. According to claim 1,
The polishing layer has an elastic modulus of 70 to 200 N/mm ² .
polishing pad. According to claim 1,
The elongation of the polishing layer is 60 to 140%
polishing pad. i) preparing a prepolymer composition;
ii) preparing a composition for preparing an abrasive layer including the prepolymer composition, a foaming agent, and a curing agent; and
iii) preparing an abrasive layer by curing the composition for preparing an abrasive layer;
The polishing layer has a value of 0.6 to 1 according to Equation 1 below,
The value according to Equation 2 below is 0.6 to 1,
Manufacturing method of polishing pad:
[Equation 1]

[Equation 2]

The H is the surface hardness (shore D) of the polished surface of the polishing layer,
The M is the modulus of elasticity (N/mm ² ) of the polishing layer,
E is the elongation (%) of the polishing layer. According to claim 7,
Step iii) is to inject and cure the composition for preparing an abrasive layer into a preheated mold,
The preheating temperature of the mold is 60 to 80 ° C.
Method for manufacturing an abrasive pad. 1) providing a polishing pad including a polishing layer; and
2) polishing the semiconductor substrate while relatively rotating it so that the polishing surface of the semiconductor substrate comes into 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,
The value according to Equation 2 below is 0.6 to 1,
Manufacturing method of semiconductor device:
[Equation 1]

[Equation 2]

The H is the surface hardness (shore D) of the polished surface of the polishing layer,
The M is the modulus of elasticity (N/mm ² ) of the polishing layer,
E is the elongation (%) of the polishing layer. delete

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