KR102415203B1 - Polishing pad and preparing method of semiconductor device using the same - Google Patents

Abstract

The embodiment provides a polishing pad, a method of manufacturing the same, and a method of manufacturing a semiconductor device using the same. The polishing pad can improve the surface defect characteristics such as scratches and chatter marks appearing on the surface of the semiconductor substrate by controlling the surface zeta potential of the polishing surface and the ratio thereof to a specific range according to the type of polishing slurry, and the polishing rate can be further improved.

Description

POLISHING PAD AND PREPARING METHOD OF SEMICONDUCTOR DEVICE USING THE SAME

It relates to a pad applied to a polishing process, and to a technique for applying such a pad to a method of manufacturing a semiconductor device.

A chemical mechanical planarization (CMP) or chemical mechanical polishing (CMP) process may be performed for various purposes in various technical fields. The CMP process is performed on a predetermined polished surface of an object to be polished, and may be performed for the purposes of planarization of the polished surface, removal of aggregated materials, resolution of crystal lattice damage, and removal of scratches and contamination sources.

The CMP process technology of the semiconductor process can be classified according to the quality of the film to be polished or the shape of the surface after polishing. For example, it can be divided into single silicon or polysilicon according to the film quality to be polished, and various oxide films or tungsten (W), copper (Cu), aluminum (Al) classified according to the type of impurities. ), ruthenium (Ru), tantalum (Ta), etc. can be classified into a metal film CMP process. And, according to the shape of the surface after polishing, it can be classified into a process of alleviating the roughness of the substrate surface, a process of flattening a step caused by multi-layer circuit wiring, and an element isolation process for selectively forming circuit wiring after polishing.

The CMP process may be applied in plurality in the manufacturing process of the semiconductor device. A semiconductor device includes a plurality of layers, and each layer includes a complex and fine circuit pattern. In addition, in recent semiconductor devices, individual chip sizes are reduced, and the patterns of each layer are evolving to become more complex and finer. Accordingly, in the process of manufacturing semiconductor devices, the purpose of the CMP process has been expanded to not only planarize circuit wiring, but also separate circuit wiring and improve wiring surface, and as a result, more sophisticated and reliable CMP performance is required. .

The polishing pad used in the CMP process is a process component that processes the polished surface to a required level through friction. can see.

Republic of Korea Patent No. 10-1608901

The present invention is devised to solve the problems of the prior art.

The technical problem to be solved by the present invention is to improve the surface defect characteristics such as scratches and chatter marks appearing on the surface of a semiconductor substrate by controlling the surface zeta potential of the polishing pad and the ratio thereof to a specific range depending on the type of polishing slurry To provide a polishing pad and a method for manufacturing the same that can be applied continuously and discontinuously in each process such as a bulk process and a fine process for an oxide film with one polishing pad, and can implement an appropriate polishing rate for all of them will be.

Another object of the present invention is to provide a method of manufacturing a semiconductor device that can implement an appropriate polishing rate using the polishing pad and is useful for a polishing target layer of an oxide film.

In one embodiment of the present invention, it includes a polishing layer, wherein the polishing surface of the polishing layer has a surface zeta potential derived by the following Equation 1 with respect to the first composition having a hydrogen ion concentration (pH) of greater than 9.5 and less than or equal to 12 It has a first surface zeta potential (PZ1), which is a value, and the polishing surface of the polishing layer has a surface zeta potential value derived by the following formula 1 for a third composition having a hydrogen ion concentration (pH) of 7.5 or more and 9.5 or less. There is provided a polishing pad having three surface zeta potentials PZ3, wherein at least one of the first surface zeta potentials PZ1 and at least one of the third surface zeta potentials PZ3 satisfy Equation 2 below.

[Equation 1]

Surface zeta potential = (-) zeta potential of the fixed layer + zeta potential of the composition

[Equation 2]

1 ≤ PZ1/PZ3 ≤ 5

In another embodiment of the present invention, providing a polishing pad comprising a polishing layer; and polishing the polishing object while relatively rotating so that the polishing surface of the polishing object is in contact with the polishing surface of the polishing layer, wherein the polishing object includes an oxide film, and the polishing surface of the polishing layer is the composition of The hydrogen ion concentration (pH) has a first surface zeta potential (PZ1) which is a surface zeta potential value derived by Equation 1 with respect to the first composition having a hydrogen ion concentration (pH) greater than 9.5 and 12 or less, and the polishing surface of the polishing layer is a hydrogen ion of the composition The third composition having a concentration (pH) of 7.5 or more and 9.5 or less has a third surface zeta potential (PZ3), which is a surface zeta potential value derived by Equation 1 above, and at least one of the first surface zeta potentials (PZ1) and At least one of the third surface zeta potential PZ3 satisfies Equation 2 above.

The polishing pad according to the embodiment can improve surface defect characteristics such as scratches and chatter marks appearing on the surface of the semiconductor substrate by controlling the surface zeta potential of the polishing pad according to the type of polishing slurry, and the ratio thereof to a specific range. and the polishing rate can be further improved.

In particular, the polishing pad according to the embodiment of the present invention controls the surface zeta potential of the polishing pad, so that the surface of scratches and chatter marks in various processes such as bulk processing and fine processing of an oxide film with one polishing pad. While minimizing defects, it is possible to implement an appropriate polishing rate, and, of course, has an advantage that can be applied continuously and discontinuously to each process in the above environments with one polishing pad.

1 is a view for explaining a surface zeta potential of a polishing pad according to an embodiment.
2 is a graph showing the apparent zeta potential according to the surface movement of the polishing pad of Example 1 and the surface zeta potential of the polishing pad derived therefrom.
3 is a schematic diagram illustrating a surface zeta potential cell in an apparatus for measuring a surface zeta potential of a polishing pad according to an exemplary embodiment.
4 is a schematic flowchart of a semiconductor device manufacturing process according to an exemplary embodiment.
5 is a photograph showing the shape of a scratch on a wafer according to an embodiment.
6 is a photograph illustrating a chatter mark shape on a wafer according to an exemplary embodiment.

Advantages and features of the present invention, and a method of achieving them will become clear with reference to the following examples. However, the present invention is not limited to the embodiments disclosed below, but will be implemented in various different forms, Only the present embodiments are provided to complete the disclosure of the present invention, and to fully inform those of ordinary skill in the art to which the present invention belongs, the scope of the invention, the present invention is defined by the scope of the claims will only be

In order to clearly express various layers and regions in the drawings, the thicknesses are enlarged. And in the drawings, for convenience of description, the thickness of some layers and regions are exaggerated. Like reference numerals refer to like elements throughout.

In addition, in the present specification, when a part of a layer, film, region, plate, etc. is said to be “on” or “on” another part, this is not only when it is “directly on” another part, but also when there is another part in the middle. also includes Conversely, when we say that a part is "just above" another part, we mean that there is no other part in the middle. In addition, when a part of a layer, film, region, plate, etc. is said to be "under" or "under" another part, it is not only when it is "under" another part, but also when there is another part in between. include Conversely, when a part is said to be "just below" another part, it means that there is no other part in the middle.

In one embodiment according to the present invention, it includes a polishing layer, and the polishing surface of the polishing layer has a surface zeta derived by Equation 1 below with respect to the first composition having a hydrogen ion concentration (pH) of greater than 9.5 and less than or equal to 12. It has a first surface zeta potential (PZ1), which is a potential value, and the polishing surface of the polishing layer is a surface zeta potential value derived by Equation 1 for a third composition having a hydrogen ion concentration (pH) of 7.5 or more and 9.5 or less. There is provided a polishing pad having a third surface zeta potential (PZ3), wherein at least one of the first surface zeta potential (PZ1) and at least one of the third surface zeta potential (PZ3) satisfy Equation 2 below:

[Equation 1]

Surface zeta potential = (-) zeta potential of the fixed layer + zeta potential of the composition

[Equation 2]

1 ≤ PZ1/PZ3 ≤ 5

A polishing process in a semiconductor manufacturing process is made by organically connecting a polishing pad, a polishing slurry, and a film quality to be polished, and is generally performed by supplying a polishing slurry to a contact interface between the polishing pad and the film quality to be polished. The polishing slurry is a composition including a component having electrical properties, the polishing target film quality may include a conductor or semiconductor film quality, and the polishing pad has a predetermined chemical composition. In addition, they are physically located closely to each other during the semiconductor manufacturing process. Therefore, they are mutually electrically influenced by each other due to their respective material properties and their relative positions during the process.

In the electrical characteristics of the polishing pad, polishing slurry, and film quality to be polished, mutual attraction and repulsion must be implemented at an appropriate level to prevent defects on the polishing target film, which appear as scratches and chatter marks. While being minimized, it is possible to realize desired polishing performance in terms of polishing rate and flatness. For example, if the electrical attraction between the polishing pad, the polishing slurry, and the film quality to be polished is too strong, aggregation of abrasive particles in the polishing slurry occurs on the polishing pad, and defects such as scratches or chatter marks on the surface of the film quality to be polished can cause For example, if the electrical repulsion force between the polishing pad, the polishing slurry, and the film quality to be polished is too strong, the polishing rate of the film quality to be polished is lowered, which may cause problems in terms of process efficiency and polishing flatness. Therefore, it is a very important factor to control the electrical characteristics between the polishing pad, the polishing slurry, and the film quality to be polished to an appropriate level.

Zeta potential generally refers to the physical properties exhibited by particles in suspension. There are two types of liquid layers that exist around particles. It is an outer region (Defuse) in which ions are relatively weakly coupled to an inner region (Stem layer: electron layer) that forms a strong boundary. Defuse is a region within the theoretical boundary where ions and particles are stably present. For example, when a particle moves, the ions in the inner region move within a predetermined boundary. On the other hand, ions existing outside the predetermined boundary move independently like a huge dispersant regardless of the particles. The potential at this boundary is the zeta potential. The abrasive slurry has its own zeta potential as a suspension in which the abrasive particles are dispersed.

Since the polishing pad is not a suspension state as a cured resin, it does not have a generally defined zeta potential. In one embodiment, the surface zeta potential is devised as an index for representing the polishing performance of the polishing pad, and the surface zeta potential of the polishing pad is expressed in Equation 1 above in relation to a standard composition in a suspension state having a predetermined zeta potential. can be defined as

Hereinafter, the surface zeta potential of the polishing pad will be described in more detail with reference to FIG. 1 .

1 is a schematic diagram for explaining a surface zeta potential of a polishing pad. Referring to FIG. 1 , the polishing pad 100 may include a polishing layer 10 . The polishing layer 10 may include a polishing surface 11 for polishing by directly or indirectly contacting the polishing target film quality. The polishing pad 100 may be formed of a single layer of the polishing layer 10 , or may have a multi-layer structure including the polishing layer 10 . Referring to FIG. 1 , the polishing pad 100 according to an exemplary embodiment may include an adhesive layer 30 and a cushion layer 20 on one surface of the polishing layer 10 , but is not limited thereto.

The polishing pad 100 has a fixed layer 110, an ion diffusion layer 120 and a slipping plane 130 when a predetermined standard composition having its own zeta potential is supplied on the polishing surface 11 thereof. do. The pinned layer 110 is a layer formed by stably presenting particles in the standard composition on the polishing surface 11, and is a region corresponding to an internal region (Stem layer: electron layer) in a general zeta potential defined in the suspension. to be. The ion diffusion layer 120 is a region in which particles in the standard composition are relatively weakly bonded to the polishing surface 11 compared to the fixed layer 110, and is spaced apart from the polishing surface 11 by a predetermined distance. is the area The ion diffusion layer 120 is a region corresponding to the outer region Defuse in a general zeta potential defined in the suspension. The slippery surface 130 exists at the interface between the ion diffusion layer 120 and the pinned layer 110 , and the pinned layer 110 and the ion diffusion layer 120 are separated by this boundary. The slippery surface 130 is a portion corresponding to a predetermined boundary in a general zeta potential defined in the suspension.

In one embodiment, the surface zeta potential of the polishing pad according to Equation 1 is defined as the sum of a negative (-) value added to the zeta potential value of the pinned layer 110 and the zeta potential value of the corresponding standard composition. For example, as shown in FIG. 1 , when the charge of the pinned layer 110 is positive (+), the surface of the polishing surface adjacent to the pinned layer 110 will have a negative (-) charge. it can be seen that Accordingly, in deriving the surface zeta potential of the polishing pad, a value obtained by adding (-) to the zeta potential value of the pinned layer 110 is applied. The zeta potential of the pinned layer 110 is defined as the value of the Y-intercept of the graph after deriving a change in the zeta potential according to the distance from the polishing surface for the particles in the standard composition as a graph. The zeta potential of the particle is measured by electrophoretic mobility.

When the polishing pad satisfies the predetermined condition related to the surface zeta potential according to Equation 1, that is, the condition according to Equation 2, the interaction between the polishing pad and the polishing slurry to be used in the process of applying the same and the film quality to be polished It is possible to implement reliable polishing performance for the oxide film, and in particular, in various processes such as a bulk process and a fine process for an oxide film, it is possible to implement an improved polishing rate while minimizing surface defects such as scratches and chatter marks.

In the polishing pad according to the embodiment, the zeta potential of the fixed layer of Equation 1 may vary depending on the chemical and physical properties of the polishing layer of the polishing pad and the type of the standard composition. Let IZ1 be the zeta potential of the first fixed layer measured with respect to the polishing surface of the polishing pad using the first composition, and the zeta of the third fixed layer measured with respect to the polishing surface of the polishing pad using the third composition When the potential is referred to as IZ3, the zeta potential value of IZ1 of the pinned layer for the first composition is about +5 mV to about +30 mV, and IZ3, which is the value of the zeta potential of the pinned layer for the third composition, is about -15 mV to about +10 mV can be

Specifically, the first pinned bed zeta potential IZ1 is about +5 mV to about +30 mV, for example, about +8 mV to about +28 mV, for example, about +10 mV to about +25 mV, for example about from +11 mV to about +23 mV, for example from about +15 mV to about +25 mV. The third pinned bed zeta potential IZ3 is about -15 mV to about +10 mV, for example about -10 mV to about +8 mV, for example about -10 mV to about +7 mV, for example about -9 mV. to about +6 mV, for example from about -8.8 mV to about +6 mV.

The first composition and the third composition have different hydrogen ion concentrations (pH) of their own compositions, and the surface zeta potential of the polishing surface for each composition is different from each other. The fact that the ratio of the first surface zeta potential (PZ1) derived from the first composition to the third surface zeta potential (PZ3) derived from the third composition satisfies a predetermined range means that the polishing pad is applied to an actual process. In various processes such as bulk process and fine process for an oxide film to be polished, polishing can be performed with excellent performance while minimizing surface defects such as scratches and chatter marks, and with one polishing pad, each of the environments It has technical significance that it can be applied continuously and discontinuously to the process.

In one embodiment, the hydrogen ion concentration (pH) of the first composition may be greater than 9.5, 12 or less, for example, 10 to 12, for example, 10 to 11.5, for example, 10.5 ( ±0.5).

In one embodiment, the hydrogen ion concentration (pH) of the third composition may be 7.5 or more and 9.5 or less, for example, 7.8 to 9.3, for example, 7.8 to 9, for example. , may be 8.5 (±0.5).

The first composition and the third composition may be a basic slurry. However, the first composition is a silica slurry, and the third composition is a ceria slurry, and they have a pH value of, for example, about 0.5 to 4.5, for example, about 0.5 to 4, for example, about 1 to about 1 to each other. 3.5, for example, about 1 to 3 may vary. In this case, the silica slurry may refer to a composition or slurry containing silica particles, and the ceria slurry may refer to a composition or slurry containing ceria particles.

In one embodiment, the first composition comprises silica particles having an average particle diameter of about 130 nm to about 160 nm, a zeta potential of -50 mV to -30 mV, and the third composition has an average particle diameter of about 130 nm to about 170 nm It contains ceria particles and may have a zeta potential of -55 mV to -35 mV.

In one embodiment, the first composition may include fumed silica particles, and the third composition may include ceria particles, for example, wet ceria particles. Each of the above-mentioned compositions has the zeta potential value, and at the same time, the surface zeta potential of the first composition including fumed silica particles and the third composition including ceria particles is a polished surface that satisfies the condition of Equation 2 above. A polishing pad having an oxide film has the advantage of ensuring excellent polishing performance for both, when bulk and fine polishing processes for a polishing object having an oxide film are performed continuously or discontinuously.

In one embodiment, the fumed silica particles may have an average particle diameter of 130 nm to 160 nm, for example, 140 nm to 160 nm, for example, 150 (±5) nm. In one embodiment, the ceria particles may be 130 nm to 170 nm, for example, 140 nm to 160 nm, for example, 150 (±5) nm. The surface zeta potential of the first composition including fumed silica particles having the aforementioned average particle diameter and the third composition including ceria particles having the aforementioned average particle diameter, each having the above-mentioned composition zeta potential value, at the same time, is A polishing pad having a polishing surface that satisfies the condition of Equation 2 has excellent polishing performance for both bulk and fine processing for an oxide film when the bulk process and the fine polishing process for the polishing object having the oxide film are continuously or discontinuously performed. has the advantage of ensuring

The first composition may be a composition having a zeta potential of -50 mV to -30 mV of its own composition. The zeta potential of the first composition is, for example, -50 mV to -35 mV, such as -48 mV to -35 mV, such as -47 mV to -35 mV, such as -46 mV to -38 mV, such as For example, -45mV to -38mV, such as -44mV to -38mV, such as -43mV to -38mV, such as -42mV to -38mV, such as -42mV to -40mV, such as For example, it may be -42mV to -41mV.

The zeta potential of the third composition may be a composition in which the zeta potential of the composition itself is -55mV to -35mV. The zeta potential of the third composition is, for example, -50mV to -35mV, for example -50mV to -40mV, for example -50mV to -43mV, for example -48mV to -43mV, for example For example, it may be -47mV to -43mV, for example, -46mV to -43mV, for example, -46mV to -44mV.

The zeta potentials of the first composition and the third composition each have a fixed value in one of the numerical ranges described above. Accordingly, the first surface zeta potential (PZ1) and the third surface zeta potential (PZ3) derived by the first composition and the third composition also have one fixed value, respectively.

The PZ1 is, for example, -70 mV to -45 mV, for example, -70 mV to -48 mV, for example, -69 mV to -50 mV, for example, -68 mV to -50 mV, for example -67 mV to -50 mV, for example, -66 mV to -51 mV, for example, -65 mV to -51 mV.

The PZ3 is, for example, -60mV to -30mV, for example, -58mV to -30mV, for example, -56mV to -32mV, for example, -55mV to -32mV, for example -55mV to -35 mV, for example, -54 mV to -35 mV, for example, -52 mV to -35 mV.

In the polishing pad according to an embodiment, as long as at least one PZ1 value and at least one PZ3 value satisfy the condition of Equation 2, another PZ1 value and another PZ3 value satisfy the condition of Equation 2 Even if it is not satisfied, the advantages aimed at the present invention can be realized. That is, the condition of Equation 2 is that the ratio (PZ1/PZ3) of at least one of the first surface zeta potential (PZ1) and the third surface zeta potential (PZ3) of the polished surface is 1 to 5 As falling within the range, said PZ1/PZ3 is, for example, greater than 1, less than or equal to 5, such as greater than 1, less than or equal to 3, such as greater than or equal to 1, less than or equal to 2, such as 1.05 to 1.8, such as For example, it may be 1.05 to 1.5.

The zeta potential of each of the first composition and the third composition may be determined by a component thereof and each content thereof. Any two compositions containing the same component in the same content have the same zeta potential value, but just because any two compositions have the same zeta potential value does not necessarily include the same component in the same content.

Each of the compositions has the above-described zeta potential value, and at the same time, the surface zeta potential for the first composition having the above-mentioned pH value and the third composition having the above-mentioned pH value is a polished surface satisfying the condition of Equation 2 The polishing pad having an excellent polishing performance for both the bulk process and the fine process for the oxide film and reduction of surface defects such as scratches and chatter marks when the bulk process and the fine polishing process for the oxide film are performed continuously or discontinuously. have an advantage

In one embodiment, the polishing pad may have a polishing rate (OR1) of 2750 Å/min or more and less than 2955 Å/min when the oxide film is polished using the first composition with respect to the polishing surface thereof. The OR1 is, for example, 2780 Å/min or more, less than 2955 Å/min, such as 2800 Å/min or more, less than 2955 Å/min, such as 2850 Å/min to 2952 Å/min, e.g. For example, 2890 Å/min to 2950 Å/min, eg, greater than 2900 Å/min, less than or equal to 2950 Å/min, eg, 2920 Å/min to 2950 Å/min.

The polishing pad may have a polishing rate (OR3) of 2200 Å/min to 2955 Å/min when the oxide film is polished using the third composition with respect to the polishing surface thereof. The OR3 is, for example, between 2200 Å/min and 2800 Å/min, eg between 2200 Å/min and 2700 Å/min, eg between 2200 Å/min and 2600 Å/min, eg 2300 It may be between Å/min and 2600 Å/min.

The polishing pad has a ratio of OR1 to OR3 (OR1/OR3) of 1.0 to 1.5, for example, 1.1 to 1.4, for example, 1.12 to 1.30, for example, 1.12 to 1.17, for example, It may be 1.24 to 1.30.

In the various processes of the bulk process and the fine process for the oxide film of the polishing pad using the silica polishing slurry and/or the ceria polishing slurry, the OR1 and OR3 determine whether the factor for the polishing rate is implemented at a desired level. It can be an indirect indicator that can be The polishing performance may be evaluated in consideration of not only the polishing rate, but also various performances such as polishing selectivity and the degree of occurrence of structural defects. The polishing pad according to an exemplary embodiment has a polishing surface that satisfies the conditions of Equation 2 and at the same time satisfies the items related to OR1 and OR3, and can implement an appropriate polishing rate, and at the same time can perform dishing, scratching ( It is possible to realize the advantage of minimizing structural defects such as scratches and chatter marks.

In one embodiment, the polishing layer may have a porous structure including a plurality of pores. Specifically, the number average diameter of the plurality of pores included in the polishing layer is about 10 μm to about 40 μm, for example, about 10 μm to about 35 μm, for example, about 12 μm to about 30 μm, for example For example, it may be about 14 μm to about 30 μm, for example, about 16 μm to about 30 μm, for example, about 14 μm to about 28 μm, for example, about 16 μm to about 28 μm. The number average diameter of the pores may be defined as an average value obtained by dividing the sum of the plurality of pore diameters by the number of the plurality of pores.

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

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

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

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

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

The isocyanate compound is, for example, 2,4-toluene diisocyanate (2,4-toluene diisocyanate, 2,4-TDI), 2,6-toluene diisocyanate (2,6-toluene diisocyanate, 2,6- TDI) naphthalene-1,5-diisocyanate, p-phenylene diisocyanate, tolidine diisocyanate, 4,4'-diphenyl methane selected from the group consisting of 4,4'-diphenyl methane diisocyanate, hexamethylene diisocyanate, dicyclohexylmethane diisocyanate, isophorone diisocyanate, and combinations thereof may contain one.

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

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

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

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

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

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

In another embodiment, the isocyanate compound for preparing the urethane-based prepolymer may include an aromatic diisocyanate compound and an alicyclic diisocyanate compound, for example, the aromatic diisocyanate compound is 2,4-toluene diisocyanate (2 ,4-TDI) and 2,6-toluene diisocyanate (2,6-TDI), and the alicyclic diisocyanate compound may include dicyclohexylmethane diisocyanate (H12MDI). The polyol compound for preparing the urethane-based prepolymer may include polytetramethylene ether glycol (PTMEG) and diethylene glycol (DEG).

The urethane-based prepolymer has an isocyanate end group content (NCO%) of about 5 wt% to about 11 wt%, for example, about 5 wt% to about 10 wt%, for example, about 5 wt% to about 8 wt% , for example, from about 8% to about 10% by weight.

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

When the isocyanate end group content (NCO%) of the urethane-based prepolymer satisfies the above-mentioned range, the reaction rate, reaction time, and final curing structure when the urethane-based prepolymer and the curing agent are subsequently reacted depend on the use of the final polishing pad and It can be adjusted in a direction favorable to the polishing performance according to the purpose of use.

In one embodiment, the isocyanate end group content (NCO%) of the urethane crab prepolymer may be about 8 wt% to about 10 wt%, for example, about 8 wt% to about 9.4 wt%. When the NCO% is less than the above range, the first surface zeta potential and the third surface zeta potential as electrical properties based on a chemically hardened structure in the polishing pad do not realize the desired polishing performance in terms of polishing rate and flatness. It can be implemented to prevent it, and there may be a problem in that the life of the polishing pad is reduced due to an excessive increase in the cutting rate. On the other hand, when the NCO% exceeds the above range, surface defects such as scratches and chatter marks of the semiconductor substrate may increase.

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

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

The curing agent may be in an amount of 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. . When the content of the curing agent satisfies the above range, it may be more advantageous to realize a desired surface zeta potential ratio of the polishing pad.

In one embodiment, the curing agent may include 4,4'-methylenebis(2-chloroaniline) or dimethylthiotoluenediamine, and the curing agent is used in an amount of about 21 parts by weight to about 26 parts by weight based on 100 parts by weight of the urethane-based prepolymer. may contain Through this, the urethane cured structure in the polishing layer can exhibit electrical characteristics based on chemical characteristics according to the reaction of the urethane-based prepolymer and the curing agent, and these electrical characteristics are the target range for polishing performance to be realized through the polishing pad. It may be advantageous to implement as

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

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

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

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

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

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

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

The chlorofluoro compound is trichlorofluoromethane (trichlorofluoromethane, CCl ₃ F), dichlorodifluoromethane (dichlorodifluoromethane, CCl ₂ F ₂ ), chlorotrifluoromethane (chlorotrifluoromethane, CClF ₃ ), tetrafluoroethylene ( tetrafluoroethylene, CClF ₂ -CClF ₂ ) and a combination thereof may include one selected from the group consisting of.

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

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

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

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

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

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

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

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

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

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

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

In one embodiment, the solid foaming agent may include expandable particles that are not treated with inorganic components. Specifically, the solid foaming agent may be formed of expandable particles that are not treated with inorganic components. By using expandable particles that are not treated with inorganic components as the solid foaming agent, chemical and electrical properties of the surface of the solid foaming agent may be advantageous in realizing a desired surface zeta potential characteristic.

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

The gas-phase foaming agent may include nitrogen gas.

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

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

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

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

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

Specifically, the reaction rate controlling agent is triethylenediamine, dimethylethanolamine, tetramethylbutanediamine, 2-methyl-triethylenediamine, dimethylcyclohexylamine, triethylamine, triisopropanolamine, 1,4-diazabicyclo( 2,2,2)octane, bis(2-methylaminoethyl)ether, trimethylaminoethylethanolamine, N,N,N,N,N''-pentamethyldiethylenetriamine, dimethylaminoethylamine, dimethylamino Propylamine, benzyldimethylamine, N-ethylmorpholine, N,N-dimethylaminoethylmorpholine, N,N-dimethylcyclohexylamine, 2-methyl-2-azanovonein, dibutyltin dilaurate, Contains at least one selected from the group consisting of stannous octoate, dibutyltin diacetate, dioctyltin diacetate, dibutyltin maleate, dibutyltin di-2-ethylhexanoate and dibutyltin dimercaptide can do. Specifically, the reaction rate controlling agent may include at least one selected from the group consisting of benzyldimethylamine, N,N-dimethylcyclohexylamine and triethylamine.

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

In one embodiment, the content of the inorganic material in the polishing layer may be about 5 ppm to about 500 ppm.

The inorganic material may include, for example, at least one element selected from the group consisting of a silicon (Si) element, a phosphorus (P) element, and a calcium (Ca) element.

The inorganic material may be derived from various sources. For example, the inorganic material may be derived from various additives used in the manufacturing process of the polishing layer, such as a foaming agent. In this case, the additive serving as the source of the inorganic material may include, for example, one selected from the group consisting of a foaming agent, a surfactant, a reaction rate regulator, and a combination thereof.

The content of inorganic substances in the abrasive layer may be designed in an appropriate range by using only one of the foaming agent or other additives and controlling the type and content, or by using the foaming agent and other additives simultaneously and controlling the type and content. It may be designed in an appropriate range.

The content of the inorganic material in the polishing layer is about 5 ppm to about 500 ppm, for example, about 5 ppm to about 400 ppm, for example, about 8 ppm to about 300 ppm, for example, about 220 ppm to about 400 ppm, for example, about 5 ppm to about 180 ppm. At this time, the content of the inorganic material in the polishing layer may be measured by inductively coupled plasma (ICP: Inductively Coupled Plasma Atomic Emission Spectrometer) analysis.

The content of the inorganic material in the polishing layer may have a significant effect on the surface zeta potential of the polishing pad. Accordingly, the surface zeta potential ratio of the polishing pad may be implemented within a predetermined range. If the content of the inorganic material exceeds about 500 ppm in the polishing layer, the composition of the polishing layer may be changed, so that the surface zeta potential of the polishing pad may vary. Electrical correlation may be modified in a direction to significantly increase surface defects such as scratches and chatter marks of the semiconductor substrate.

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

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

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

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

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

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

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

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

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

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

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

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

In one embodiment, the temperature difference between the first temperature and the second temperature may be about 10 °C to about 40 °C, for example, about 10 °C to about 35 °C, for example, about 15 °C to about 35°C.

In one embodiment, the first temperature may be about 60 °C to about 100 °C, for example, about 65 °C to about 95 °C, for example, about 70 °C to about 90 °C.

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

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

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

The method of manufacturing the polishing pad may include processing at least one surface of the polishing layer.

The step of machining at least one surface of the abrasive layer may include the steps of (1) forming a groove on at least one surface of the abrasive layer; line turning (2) at least one surface of the abrasive layer; and roughening at least one surface of the polishing layer (3).

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

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

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

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

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

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

The cushion layer serves to absorb and disperse an external shock applied to the polishing layer while supporting the polishing layer, thereby minimizing damage and defects to the polishing object during the polishing process to which the polishing pad is applied.

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

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

The resin impregnated into the nonwoven fabric is a polyurethane resin, polybutadiene resin, styrene-butadiene copolymer resin, styrene-butadiene-styrene copolymer resin, acrylonitrile-butadiene copolymer resin, styrene-ethylene-butadiene-styrene copolymer resin, silicone rubber resin , it may include one selected from the group consisting of a polyester-based elastomer resin, a polyamide-based elastomer resin, and combinations thereof.

In another embodiment according to the present invention, providing a polishing pad comprising a polishing layer; and polishing the polishing object while relatively rotating so that the polishing surface of the polishing object comes into contact with the polishing surface of the polishing layer, wherein the polishing object includes an oxide film, and the polishing surface of the polishing layer is a composition The hydrogen ion concentration (pH) has a first surface zeta potential (PZ1), which is a surface zeta potential value derived by Equation 1 for the first composition having a hydrogen ion concentration (pH) greater than 9.5 and 12 or less, and the polishing surface of the polishing layer is a hydrogen ion of the composition The third composition having a concentration (pH) of 7.5 or more and 9.5 or less has a third surface zeta potential (PZ3), which is a surface zeta potential value derived by Equation 1 below, and at least one of the first surface zeta potentials (PZ1) and At least one of the third surface zeta potential (PZ3) satisfies Equation 2 below, and provides a method of manufacturing a semiconductor device:

[Equation 1]

Surface zeta potential = (-) zeta potential of the fixed layer + zeta potential of the composition

[Equation 2]

1 ≤ PZ1/PZ3 ≤ 5

4 is a schematic flowchart of a semiconductor device manufacturing process according to an exemplary embodiment. Referring to FIG. 4 , after the polishing pad 410 according to the embodiment is mounted on the surface plate 420 , a semiconductor substrate 430 to be polished is disposed on the polishing pad 410 . In this case, the polished surface of the semiconductor substrate 430 is in direct contact with the polishing surface of the polishing pad 410 . For polishing, the polishing slurry 450 may be sprayed onto the polishing pad through the nozzle 440 . The flow rate of the polishing slurry 450 supplied through the nozzle 440 may be selected according to the purpose within the range of about 10 cm 3 /min to about 1,000 cm 3 /min, for example, from about 50 cm 3 /min to about It may be 500 ㎤ / min, but is not limited thereto.

Thereafter, the semiconductor substrate 430 and the polishing pad 410 may be rotated relative to each other, so that the surface of the semiconductor substrate 430 may be polished. In this case, the rotation direction of the semiconductor substrate 430 and the rotation direction of the polishing pad 410 may be in the same direction or in opposite directions. The rotation speed of the semiconductor substrate 430 and the polishing pad 410 may be selected depending on the purpose in the range of about 10 rpm to about 500 rpm, respectively, for example, it may be about 30 rpm to about 200 rpm, However, the present invention is not limited thereto.

The semiconductor substrate 430 may be polished while being mounted on the polishing head 460 by being pressed against the polishing surface of the polishing pad 410 with a predetermined load to make contact with the polishing head 460 . The load applied to the polishing surface of the polishing pad 410 on the surface of the semiconductor substrate 430 by the polishing head 460 may be selected from about 1 gf/cm 2 to about 1,000 gf/cm 2 depending on the purpose. and may be, for example, about 10 gf/cm 2 to about 800 gf/cm 2 , but is not limited thereto.

Specifically, the semiconductor substrate 430 may include an oxide layer. In addition, since the polishing pad has a predetermined electrical characteristic according to Equation 2, it can have excellent polishing performance in a multi-process such as a bulk process and a fine process for the oxide film. In addition, since the polishing pad has a predetermined electrical characteristic according to Equation 2, a semiconductor device manufactured according to the method of manufacturing the semiconductor device may have excellent flatness and circuit characteristics.

In an embodiment, the method of manufacturing the semiconductor device may further include supplying a slurry for polishing the oxide film in the polishing of the object to be polished. For example, in the method of manufacturing the semiconductor device, in the step of polishing the object to be polished, as a slurry for polishing an oxide film, any one of a slurry containing silica particles (silica slurry) and a slurry containing ceria particles (ceria slurry) supplying; Alternatively, the method may further include sequentially supplying the slurry containing the silica particles and the slurry containing the ceria particles to the polishing surface.

For example, the semiconductor substrate to be polished includes an oxide layer, and as a slurry for polishing the oxide layer, the method may include supplying a slurry including silica particles. Alternatively, as the oxide film polishing slurry, it may include supplying a slurry containing ceria particles. Alternatively, the oxide film polishing slurry may include sequentially supplying a slurry containing silica particles and a slurry containing ceria particles to the polishing surface. At this time, according to the process, the slurry containing the silica particles may be supplied first and then the slurry containing the ceria particles may be supplied later, or the slurry containing the ceria particles may be supplied first, and then the slurry containing the silica particles is later supplied. can also supply.

In one embodiment, in the method of manufacturing the semiconductor device, in order to maintain the polishing surface of the polishing pad 410 in a state suitable for polishing, the semiconductor substrate 430 is polished and simultaneously polished through the conditioner 470 . The method may further include processing the polishing surface of the pad 410 .

In the polishing pad according to the embodiment, since the polishing surface of the polishing layer has a predetermined surface zeta potential characteristic, polishing performance for the oxide film can be implemented at an excellent level, and in particular, the bulk process and the fine process for the oxide film Polishing performance for all can be realized at an excellent level. Accordingly, it is possible to efficiently manufacture a semiconductor device of excellent quality using the polishing pad.

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

<Examples and Comparative Examples>

Example 1

1-1: Preparation of urethane-based prepolymer

2,4-toluene diisocyanate (2,4-TDI), 2,6-toluene diisocyanate (2,6-TDI) dicyclohexylmethane diisocyanate (H12MDI), polytetramethylene ether glycol (PTMEG) and diethylene Glycol (DEG) was added to a four-neck flask and reacted at 80 °C for 3 hours to prepare a urethane-based prepolymer having an NCO group content of 9.1 wt%.

1-2: Configuration of the device

Equipment equipped with a urethane-based prepolymer tank, a curing agent tank, and an inert gas injection line directly or indirectly connected to the mold was prepared. The urethane-based prepolymer and the solid foaming agent (manufacturer: Akzonobel, product name: Expancel 551 DE 40 d42, average particle diameter: 40 μm) prepared before the urethane-based prepolymer tank were added and mixed. 2.2 parts by weight of the solid foaming agent was used based on 100 parts by weight of the urethane-based prepolymer. 4,4'-methylenebis(2-chloroaniline) (4,4'-methylenebis(2-chloroaniline); MOCA) was filled in the curing agent tank.

1-3. Preparation of the abrasive layer

The urethane-based prepolymer, the solid foaming agent, and the curing agent were mixed in a mixing head through each input line while inputting the curing agent at a predetermined speed. 25 parts by weight of the curing agent was added based on 100 parts by weight of the urethane-based prepolymer. The rotation speed of the mixing head was about 5,000 rpm. The mixed composition including the urethane-based prepolymer, the solid foaming agent and the curing agent was mixed in the mixing head and then injected into a mold having a width of 1,000 mm, a length of 1,000 mm, and a height of 3 mm. The temperature of the mold was adjusted to about 80 (±5) °C. The mixed composition was solidified in the mold to prepare a sheet for an abrasive layer. An abrasive layer was prepared by post-curing the sheet at about 110 (±5)° C. for about 18 hours.

1-4. Manufacture of polishing pad

One surface of the abrasive layer was turned by using a cutting tool and grooved using a tip to prepare an average thickness of 2 mm. A cushion layer impregnated with a polyurethane resin was prepared on a polyester fiber nonwoven fabric, and a heat-sealing adhesive was applied to one surface of the cushion layer and the back surface of the grooved surface of the polishing layer, respectively. The cushion layer and the abrasive layer are laminated so that the surfaces to which each heat-sealing adhesive is applied are in contact, and the abrasive pad is formed by pressure lamination at a temperature of about 140 (±5)° C. and a pressure of 2 kgf/cm 2 using a pressure roller. prepared.

Example 2

As shown in Table 1 below, as a foaming agent, a solid foaming agent (manufacturer: Akzonobel, product name: Expancel 461 DE 20 d70, average particle diameter: 20 μm) was used, except that the number average diameter of pores in the abrasive layer was adjusted through this. produced a polishing pad in the same manner as in Example 1.

Example 3

As shown in Table 1 below, a solid foaming agent (manufacturer: Akzonobel, product name: Expancel 551 DE 40 d42, average particle diameter: 40 μm) was used as a foaming agent, and a mixed composition comprising the urethane-based prepolymer, the solid foaming agent and the curing agent was When mixing in the mixing head, a gaseous foaming agent (nitrogen gas (N ₂ )) was mixed and used through a separate input line. 1,5 parts by weight of the solid foaming agent was used based on 100 parts by weight of the urethane-based prepolymer. Meanwhile, a silicone surfactant (manufacturer: Evonik, product name: B8462) as a surfactant was added during the preparation of the mixed composition. Through this, a polishing pad was manufactured in the same manner as in Example 1, except that the number average diameter and inorganic content of the pores in the polishing layer were adjusted.

Example 4

As shown in Table 1 below, only nitrogen gas (N ₂ ), which is a gas-phase foaming agent, was used without using a solid foaming agent as a foaming agent, and a surfactant was added during the preparation of a mixed composition including the urethane-based prepolymer and the curing agent. A polishing pad was prepared in the same manner as in Example 1, except that the content of the surfactant, the number average diameter of pores in the polishing layer, and the content of the inorganic material were adjusted as shown in Table 1 below.

Example 5

As shown in Table 1 below, dimethyl thio-toluene diamine (DMTDA) was used as a curing agent and the number average diameter of pores in the polishing layer and the content of inorganic material (Si) in the polishing layer were adjusted, except that, A polishing pad was prepared in the same manner as in Example 3.

Comparative Example 1

As shown in Table 1 below, the type of the solid foaming agent (manufacturer: Akzonobel, product name: Expancel 461 DET 40 d25, average particle diameter: 40 μm) was changed and the number average diameter of pores in the abrasive layer and the inorganic content were adjusted except for Then, a polishing pad was manufactured in the same manner as in Example 3.

Comparative Example 2

As shown in Table 1 below, in the same manner as in Comparative Example 1, except that dimethyl thio-toluene diamine (DMTDA) was used as a curing agent and the number average diameter and inorganic content of pores in the polishing layer were adjusted. A polishing pad was manufactured.

Specific components and properties of the polishing layer are summarized in Table 1 below.

Parts by weight in Table 1 below are values based on 100 parts by weight of the urethane-based prepolymer.

division Example 1 Example 2 Example 3 Example 4 Example 5 Comparative Example 1 comparative example
2 pad
Produce Hardener content
(parts by weight) MOCA
(25) MOCA
(25) MOCA
(25) MOCA
(25) DMTDA
(21.4) MOCA
(25) DMTDA
(21.4) blowing agent
(volume % based on total pore volume) elegance solid B
100% solid C
100% solid B
50% - Solid B 50% Solid A 50% solid A
50% weather - - N ₂ 50% N ₂ 100% N ₂ 50% N ₂ 50% N ₂ 50% Surfactants
Content (parts by weight) 0 0 0.5 0.5 0.5 0.5 0.5 pore number average
Diameter (㎛) 24.1 16.0 21.0 26.0 21.0 24.0 21.0 Mineral content (%) 300 223 103 0 165 9740 9536 Solid A Solid foaming agent-Manufacturer: Akzonobel, product name: Expancel 461 DET 40 d25, average particle diameter: 40 μm
Solid B: Solid foaming agent-Manufacturer: Akzonobel, product name: Expancel 551 DE 40 d42, average particle diameter: 40 μm
Solid C: Solid foaming agent-Manufacturer: Akzonobel, product name: Expancel 461 DE 20 d70, average particle diameter: 20 μm
The volume% of the solid foam and the gas-phase foaming agent may mean the volume% of the pores derived by each of the foaming agents.

<Evaluation>

Experimental Example 1: Preparation of abrasive slurry

As shown in Table 2 below, a first polishing slurry and a third polishing slurry were prepared.

first polishing slurry third abrasive slurry Slurry Type Fumed Silica Slurry ceria slurry composition ratio Fumed silica particles: 12 wt% wet ceria
Particles: 5% by weight pH adjuster (KOH): 0.2% Dispersant: Polyacrylic acid:
(poly acrylic acid)
0.2% remaining amount of deionized water Solid content (% by weight) 12 5 pH 10.5 8.5 Zeta potential of the slurry (mV) -41.3 mV -44.9 mV Average particle size (nm) 150 nm 150 nm dilution concentration 12% → 0.5% sol. 5% → 0.5% sol.

Test Example 2: Measurement of physical properties of polishing pad

2-1. Surface Zeta Potential Measurement of Polishing Pads

Examples and Comparative Examples The surface zeta potential of the polishing pad was measured using a zeta potential measuring device, ZETASIZER Nano-ZS90 (Malvern).

The zeta potential measuring device is a dip cell type, has an electrode at the end of the barrel (a specimen is attached therebetween), and includes an avalanche photo-iod detection system.

Specifically, FIG. 3 is a schematic diagram showing a surface zeta potential cell. 3, the polishing pad samples (4mm X 5mm, 20 mm ² ) obtained in Examples and Comparative Examples are attached to the sample holder 310 using double-sided tape, and the first to the cuvette 330. 2 ml of the polishing slurry or the third polishing slurry was diluted to the dilution concentration shown in Table 2, and electrophoretic mobility was measured using the Ag/AgCl reversible electrode 320 . The measured electrophoretic mobility was changed as a function of the distance from the sample surface, and the surface zeta potential of the polishing pad was calculated using Equation 1 below.

[Equation 1]

Surface zeta potential = (-) zeta potential of the fixed layer + zeta potential of the composition.

In Equation 1, the zeta potential of the pinned layer 110 is extrapolated by measuring the ion diffusion layer 120 of FIG. 1 .

FIG. 2 is a graph of measuring an apparent zeta potential with respect to a surface displacement of a polishing surface of the polishing pad of Example 1; FIG. Specifically, for the polishing surface of the polishing pad of Example 1, the apparent zeta potential for surface movement was measured using the first polishing slurry having a zeta potential of -41.3 mV of polishing slurry 1 as a tracer. Mean values and regression fit graphs are shown. With respect to the first polishing slurry having a zeta potential of -41.3 mV, the first surface zeta potential (PZ1), which is a surface zeta potential value derived by Equation 1, was measured to be -60.5 mV. At this time, the fixed bed zeta potential is 19.2 mV, the surface equivalent mobility value is -4.744 (㎛cm/Vs), the surface zeta potential uncertainty value is 4.31 (mV), and the surface equivalent mobility value is 4.31 (mV). The surface equivalent mobility uncertainty value was 0.3377 (㎛cm/Vs).

Table 3 below shows the surface zeta potentials of the polishing pads of Examples and Comparative Examples, respectively, measured according to the type of polishing slurry in this way.

2-2. Oxide film removal rate measurement

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

2-3. Measure the number of surface defects such as scratches and chatter marks

After performing the CMP process in the same manner as in Test Example (2-2) using the polishing pads of Examples and Comparative Examples, after polishing using a defect inspection equipment (AIT XP+, KLA Tencor), on the wafer surface The number of surface defects such as scratches and chatter marks that appear was measured (conditions: threshold 150, die filter threshold 280).

The scratch refers to a substantially continuous linear scratch, for example, a defect having a shape as shown in FIG. 5 .

On the other hand, the chatter mark refers to a substantially discontinuous linear scratch, for example, a shape defect as shown in FIG. 6 .

The results of the above test examples are summarized in Table 3 below.

division Example 1 Example 2 Example 3 Example 4 Example 5 Comparative Example 1 Comparative Example 2 slurry
zeta
electric potential
(mV) 1st grinding
slurry
(SZ1) -41.3 -41.3 -41.3 -41.3 -41.3 -41.3 -41.3 3rd grinding
slurry
(SZ3) -44.9 -44.9 -44.9 -44.9 -44.9 -44.9 -44.9 fixed bed
zeta potential
(mV) 1st grinding
slurry
(IZ1) 19.2 22.8 16.9 21.8 11.2 0.4 -2 3rd grinding
slurry
(IZ3) -2.8 -8.8 -5.4 5.6 3.5 17.1 16 pad
surface
zeta
electric potential
(mV) PZ1 -60.5 -64.1 -58.2 -63.1 -52.5 -41.7 -39.3 PZ3 -42.1 -36.1 -39.5 -50.5 -48.4 -62 -60.9 PZ1/PZ3 1.44 1.78 1.47 1.25 1.08 0.67 0.65 PZ1-SZ1 -19.2 -22.8 -16.9 -21.8 -11.2 -0.4 2 PZ3-SZ3 2.8 8.8 5.4 -5.6 -3.5 -17.1 -16 kite
mind
rate
(Å/
min) OR1 2931 2950 2932 2894 2948 2940 2938 OR3 2373 2256 2486 2583 2396 2495 2391 OR1/OR3 1.23 1.30 1.17 1.12 1.23 1.18 1.23 Scratch and Chatter
mark (dog) 1st grinding
slurry <5 <5 <5 <5 <5 30 30 3rd grinding
slurry <5 <5 <5 <5 <5 45 45 PZ1: The surface zeta potential of the polishing pad according to Equation 1 measured using the first polishing slurry
PZ3: The surface zeta potential of the polishing pad according to Equation 1 measured using the third polishing slurry
OR1: The polishing rate for the oxide film of the polishing pad using the first polishing slurry
OR3: the polishing rate for the oxide film of the polishing pad using the third polishing slurry

As can be seen from Table 3, when the surface zeta potential desired in the present invention is satisfied, the polishing rate and the effect of reducing surface defects such as scratches and chatter marks are higher than when the polishing pads of Comparative Examples 1 and 2 are used. It was confirmed that it was remarkably excellent.

Specifically, with respect to the polishing rate, in the case of the polishing pads of Examples 1 to 5, the polishing rate (OR1) for the oxide film of the polishing pad using the first polishing slurry is 2894 Å/min to 2950 Å/min, The polishing rate (OR3) for the oxide film of the polishing pad using the third polishing slurry ranged from 2256 Å/min to 2583 Å/min, and an appropriate polishing rate could be implemented depending on the type of slurry according to the film quality to be polished. .

In addition, with respect to surface defects such as scratches and chatter marks, when the polishing pads of Examples 1 to 5 were used, all surface defects such as scratches and chatter marks appeared on the wafer surface were less than 5, but Comparative Examples 1 and 2 It was confirmed that, when the polishing pad of

In consideration of the above, the polishing pad according to the above embodiment was able to achieve excellent polishing performance for the oxide film by controlling the surface zeta potential of the polishing surface and their ratio to a specific range depending on the type of polishing slurry. , it was found to have an excellent effect in reducing surface defects such as scratches and chatter marks appearing on the surface of the semiconductor substrate. In addition, the polishing pad can be applied to continuous and discontinuous processes in bulk and fine processes with respect to the oxide film, and by ensuring excellent polishing performance, it can have great advantages in terms of multi-processing.

100, 410: polishing pad
10: abrasive layer
11: Polishing surface
20: cushion layer
30: adhesive layer
110: fixed bed
120: diffusion layer of ions
130: slipping plane
310: sample holder
320: electrode
330: cuvette
420: surface plate
430: semiconductor substrate
440: nozzle
450: polishing slurry
460: abrasive head
470: conditioner

Claims (8)

comprising an abrasive layer;
The polishing layer includes a cured product of a composition including a urethane-based prepolymer, a curing agent and a foaming agent,
The content of inorganic substances in the polishing layer is 5 ppm to 500 ppm,
The polishing surface of the polishing layer has a first surface zeta potential (PZ1), which is a surface zeta potential value derived by the following Equation 1 with respect to a first composition having a hydrogen ion concentration (pH) of more than 9.5 and 12 or less,
The polishing surface of the polishing layer has a third surface zeta potential (PZ3), which is a surface zeta potential value derived by the following Equation 1 for a third composition having a hydrogen ion concentration (pH) of 7.5 or more and 9.5 or less,
At least one of the first surface zeta potential PZ1 and at least one of the third surface zeta potential PZ3 satisfy Equation 2 below:
[Equation 1]
Surface zeta potential = (-) zeta potential of the fixed layer + zeta potential of the composition
[Equation 2]
1 ≤ PZ1/PZ3 ≤ 5.
According to claim 1,
IZ1, which is a zeta potential value of the fixed layer with respect to the first composition, is +5mV to +30mV,
IZ3, which is a zeta potential value of the fixed layer with respect to the third composition, is -15mV to +10mV,
polishing pad.
According to claim 1,
The first composition includes silica particles having an average particle diameter of 130 nm to 160 nm, and a zeta potential of -50 mV to -30 mV,
The third composition includes ceria particles having an average particle diameter of 130 nm to 170 nm, and a zeta potential of -55 mV to -35 mV,
polishing pad.
delete According to claim 1,
The urethane-based prepolymer has an isocyanate end group content (NCO%) of 8 wt% to 10 wt%, or
The foaming agent includes a solid foaming agent having an average particle diameter of 5 μm to 200 μm, a gas phase foaming agent, or a combination thereof,
The content of the curing agent is 18 parts by weight to 27 parts by weight based on 100 parts by weight of the urethane-based prepolymer,
The abrasive layer has a porous structure including pores having a number average diameter of 10 μm to 40 μm,
polishing pad.
According to claim 1,
The polishing rate of the oxide film with respect to the polishing surface of the polishing layer using the first composition is OR1,
When the polishing rate of the oxide film with respect to the polishing surface of the polishing layer using the third composition is OR3,
wherein OR1 is greater than or equal to 2750 Å/min and less than 2955 Å/min,
wherein the OR3 is greater than or equal to 2200 Å/min and less than or equal to 2955 Å/min,
polishing pad.
providing a polishing pad comprising an abrasive layer; and
Grinding the polishing object while relatively rotating so that the polishing surface of the polishing object is in contact with the polishing surface of the polishing layer;
The polishing object includes an oxide film,
The polishing layer includes a cured product of a composition including a urethane-based prepolymer, a curing agent and a foaming agent,
The content of inorganic substances in the polishing layer is 5 ppm to 500 ppm,
The polishing surface of the polishing layer has a first surface zeta potential (PZ1), which is a surface zeta potential value derived by the following Equation 1 with respect to a first composition having a hydrogen ion concentration (pH) of more than 9.5 and 12 or less,
The polishing surface of the polishing layer has a third surface zeta potential (PZ3), which is a surface zeta potential value derived by the following Equation 1 for a third composition having a hydrogen ion concentration (pH) of 7.5 or more and 9.5 or less,
At least one of the first surface zeta potential (PZ1) and at least one of the third surface zeta potential (PZ3) satisfy Equation 2 below,
A method of manufacturing a semiconductor device:
[Equation 1]
Surface zeta potential = (-) zeta potential of the fixed layer + zeta potential of the composition
[Equation 2]
1 ≤ PZ1/PZ3 ≤ 5.
8. The method of claim 7,
In the step of polishing the polishing object,
supplying one of a slurry containing silica particles and a slurry containing ceria particles as the oxide film polishing slurry; or
Further comprising the step of sequentially supplying the slurry containing the silica particles and the slurry containing the ceria particles to the polishing surface,
A method of manufacturing a semiconductor device.

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