Polishing pad and method of manufacturing semiconductor device using the same

Abstract

The invention discloses a polishing pad and a method of manufacturing a semiconductor device using the same. Specifically, the present invention provides a polishing pad, a process for preparing the polishing pad, and a process for preparing a semiconductor device using the polishing pad. In the polishing pad, the surface zeta potential of the polishing surface and the ratio thereof are controlled within a specific range according to the type of the polishing slurry, whereby the characteristics of scratches and surface defects occurring on the surface of the semiconductor substrate can be improved, and the polishing rate can be further improved.

Description

[0001] This patent application is a divisional application of an invention patent application with an application date of August 24, 2021, an application number of 202110976626.6, a publication number of CN114083432A, and an invention name of "Polishing pad and method for preparing a semiconductor device using a polishing pad". Technical Field

[0002] The present invention relates to a pad used in a polishing process and a technique of using the pad in a process for manufacturing a semiconductor device. Background Art

[0003] In various technical fields, chemical mechanical planarization (CMP) or chemical mechanical polishing (CMP) processes may be performed for various purposes. The CMP process is performed on a specific side of the object to be polished. The process may be performed for the purpose of planarizing the side to be polished, removing accumulated material, addressing damage to the crystal lattice, and removing scratches and sources of contamination.

[0004] The CMP process technology in semiconductor processes can be classified according to the quality of the film material to be polished or the surface shape after polishing. For example, it can be classified into single crystal silicon or polycrystalline silicon according to the film material to be polished. According to the type of impurities or metal layers such as tungsten (W), copper (Cu), aluminum (Al), ruthenium (Ru) and tantalum (Ta), it can be classified into CMP processes for various oxide layers. In addition, according to the surface shape after polishing, it can be classified into a process for reducing the roughness of the substrate surface, a process for flattening the steps caused by multi-layer circuit wiring, and a device isolation process for selectively forming circuit wiring after polishing.

[0005] The CMP process may be performed several times in the process of preparing a semiconductor device. A semiconductor device includes a plurality of layers, and each layer includes a complex and fine circuit pattern. In addition, in recent years, the size of a single chip of a semiconductor device has been reduced, and the pattern of each layer has gradually developed to be more complex and fine. Therefore, in the process of preparing a semiconductor device, the purpose of the CMP process has been expanded, not only for the purpose of flattening circuit wiring, but also for the separation of circuit wiring and the application of wiring surface improvement, etc. As a result, more complex and reliable CMP performance is required.

[0006] The polishing pad used in the CMP process is a process component that processes the side to be polished to the desired level by friction. It may be one of the most important factors in terms of thickness uniformity of the object to be polished after polishing, flatness of the polished surface, and polishing quality.

[0007] Prior art document: Korean Patent No. 10-1608901 (Patent Document 1). Summary of the invention

[0008] Technical issues

[0009] An object of the present invention is to provide a polishing pad and a process for preparing the same, wherein the surface zeta potential of the polishing pad and the ratio thereof are controlled within a specific range depending on the type of polishing slurry, thereby making it possible to improve the characteristics of surface defects such as scratches and chatter marks appearing on the surface of a semiconductor substrate, and to apply a single polishing pad continuously and discontinuously to various process steps in various environments regardless of the type of silicon dioxide and the type of a target layer to be polished, while achieving an appropriate polishing rate for all of them.

[0010] Another object of the present invention is to provide a process for preparing a semiconductor device for preparing a layer to be polished of both an oxide layer and a tungsten layer using a polishing pad while achieving an appropriate polishing rate.

[0011] Solutions to the problem

[0012] The present invention provides a polishing pad, comprising a polishing layer, wherein when polishing is performed using a first composition having a hydrogen ion concentration (pH) of 8 to 12, the polishing surface of the polishing layer has a first surface zeta potential (PZ1), wherein the first surface zeta potential is a value of the surface zeta potential of the polishing surface obtained by the following equation 1 for the first composition; when polishing is performed using a second composition having a hydrogen ion concentration (pH) of 2 to 6, the polishing surface of the polishing layer has a second surface zeta potential (PZ2), wherein the second surface zeta potential (PZ2) is a value of the surface zeta potential of the polishing surface obtained by the following equation 1 for the second composition; and at least one of the first surface zeta potentials (PZ1) and at least one of the second surface zeta potentials (PZ3) satisfy the following equation 2:

[0013] [Equation 1]

[0014] Surface zeta potential = (-) zeta potential of fixed layer + zeta potential of composition

[0015] [Equation 2]

[0016]

[0017] In another embodiment of the present invention, a process for preparing a polishing pad is provided, which includes preparing a prepolymer composition; preparing a composition for preparing a polishing layer, the polishing layer including the prepolymer composition, a foaming agent and a curing agent; and curing the composition for preparing the polishing layer to prepare the polishing layer, wherein, when polishing is performed using a first composition having a hydrogen ion concentration (pH) of 8 to 12, the polishing surface of the polishing layer has a first surface zeta potential (PZ1), which is the value of the surface zeta potential of the polishing surface obtained by the above relationship 1 for the first composition; when polishing is performed using a second composition having a hydrogen ion concentration (pH) of 2 to 6, the polishing surface of the polishing layer has a second surface zeta potential (PZ2), which is the value of the surface zeta potential of the polishing surface obtained by the above relationship 1 for the second composition; and at least one of the first surface zeta potentials (PZ1) and at least one of the second surface zeta potentials (PZ2) satisfy the above relationship 2:

[0018] In another embodiment of the present invention, a process for preparing a semiconductor device is provided, the process comprising providing a polishing pad comprising a polishing layer; and relatively rotating the polishing surface of the polishing layer and the surface of an object to be polished while they are in contact with each other to polish the object to be polished, wherein the object to be polished comprises an oxide layer, a tungsten layer or a composite layer thereof, and when polishing is performed using a first composition having a hydrogen ion concentration (pH) of 8 to 12, the polishing surface of the polishing layer has a first surface zeta potential (PZ1), which is the value of the surface zeta potential of the polishing surface obtained by the above relationship 1 for the first composition; when polishing is performed using a second composition having a hydrogen ion concentration (pH) of 2 to 6, the polishing surface of the polishing layer has a second surface zeta potential (PZ2), which is the value of the surface zeta potential of the polishing surface obtained by the above relationship 1 for the second composition; and at least one of the first surface zeta potential (PZ1) and at least one of the second surface zeta potential (PZ2) satisfies the above relationship 2.

[0019] Beneficial effects of the present invention

[0020] In the polishing pad according to the embodiment, the surface zeta potential and the ratio thereof of the polishing pad are controlled within a specific range according to the type of polishing slurry, thereby improving the surface defect characteristics such as scratches and chatter marks occurring on the semiconductor substrate and further increasing the polishing rate.

[0021] In particular, in the polishing pad according to the embodiment, the surface zeta potential of the polishing pad is controlled so that an appropriate polishing rate can be achieved in a polishing environment in which an oxide layer and a tungsten layer are polished using a single polishing pad, and the single polishing pad is continuously or discontinuously applied to each process step in the above environment.

[0022] In addition, in the polishing pad according to the embodiment, the surface zeta potential of the polishing pad is controlled so that surface defects such as scratches and chatter marks can be minimized in various processes for batch and fine processing of an oxide layer using a single polishing pad while achieving an appropriate polishing rate, and the single polishing pad can be applied continuously or discontinuously to various process steps in the above environment.

[0023] In addition, in the polishing pad according to the embodiment, the surface zeta potential of the polishing pad is controlled so that a single polishing pad can be used to achieve an appropriate range of polishing performance for both silica and ceria slurries, and the single polishing pad is continuously or discontinuously applied to each process step in the above environment.

[0024] In addition, in the polishing pad according to the embodiment, the surface zeta potential of the polishing pad is controlled so that a single polishing pad can be used to achieve an appropriate range of polishing performance for acidic and alkaline slurry environments or for silica and ceria slurries, and the single polishing pad can be continuously or discontinuously applied to various process steps in the above environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 is a graph showing the surface zeta potential of the polishing pad according to the embodiment.

[0026] Figure 2 is a graph showing the apparent zeta potential of the surface displacement of the polishing pad according to Example 1 and the surface zeta potential of the polishing pad derived therefrom.

[0027] Figure 3 : is a schematic diagram showing a surface zeta potential unit in an apparatus for measuring the surface zeta potential of a polishing pad according to an embodiment.

[0028] Figure 4 A process for preparing a semiconductor device according to an embodiment is schematically illustrated.

[0029] Figure 5 is a photograph showing the shape of scratches on a wafer according to the embodiment.

[0030] Figure 6 is a photograph showing the shape of chatter marks on a wafer according to the embodiment. DETAILED DESCRIPTION

[0031] The advantages and features of the present invention and the methods for achieving the advantages and features will become apparent with reference to the following examples. However, the present invention is not limited to the embodiments disclosed below, and it can be implemented in a variety of different forms. These embodiments allow the disclosure of the present invention to be complete and enable those of ordinary skill in the art to which the present invention belongs to fully understand the scope of the present invention. The present invention is limited only by the scope of the claims.

[0032] In order to clearly show the various layers and regions in the figure, the thickness is exaggerated. For ease of explanation, the thickness of some layers and regions is exaggerated in the figure. Throughout the specification, the same reference numerals refer to the same elements.

[0033] In addition, as used herein, when a part such as a layer, film, region, plate, etc. is "on" or "over" another part, it includes not only the case where it is directly "on" another part, but also the case where another part exists therebetween. On the contrary, when a part is "directly on" another part, it means that there is no other part therebetween. In addition, as used herein, when a part such as a layer, film, region, plate, etc. is "under" or "under" another part, it includes not only the case where it is directly "under" another part, but also the case where another part exists therebetween. On the contrary, when a part is "directly under" another part, it means that there is no other part therebetween.

[0034] In an embodiment of the present invention, a polishing pad is provided, which includes a polishing layer, wherein when polishing is performed using a first composition having a hydrogen ion concentration (pH) of 8 to 12, the polishing surface of the polishing layer has a first surface zeta potential (PZ1), wherein the first surface zeta potential is a value of the surface zeta potential of the polishing surface obtained by the following equation 1 for the first composition; when polishing is performed using a second composition having a hydrogen ion concentration (pH) of 2 to 6, the polishing surface of the polishing layer has a second surface zeta potential (PZ2), wherein the second surface zeta potential (PZ2) is a value of the surface zeta potential of the polishing surface obtained by the following equation 1 for the second composition; and at least one of the first surface zeta potentials (PZ1) and at least one of the second surface zeta potentials (PZ3) satisfies the following equation 2:

[0035] [Equation 1]

[0036] Surface zeta potential = (-) zeta potential of fixed layer + zeta potential of composition

[0037] [Equation 2]

[0038]

[0039] The polishing process in the process for manufacturing semiconductors is performed in a manner in which the polishing pad, the polishing slurry, and the film material to be polished are closely associated. Generally, polishing is performed while the polishing slurry is supplied to the contact interface between the polishing pad and the film material to be polished. The polishing slurry is a composition containing components having electrical properties. The film material to be polished may include a conductor or a semiconductor film material. The polishing pad has a predetermined chemical composition. In addition, in the semiconductor manufacturing process, they are physically close to each other. Therefore, according to their respective material properties and their relative positions during the process, they have a mutual film effect.

[0040] Among the electrical properties of the polishing pad, the polishing slurry, and the film material to be polished, when the mutual attraction and repulsion reach an appropriate level, defects (such as scratches and chatter marks) on the film material to be polished can be minimized, and at the same time, the desired polishing performance in terms of polishing rate and flatness can be achieved. For example, if the electrical attraction between the polishing pad, the polishing slurry, and the film material to be polished is too strong, the polishing particles in the polishing slurry may gather on the polishing pad, thereby causing defects such as scratches or chatter marks on the surface of the film material to be polished. For example, if the electrical repulsion between the polishing pad, the polishing slurry, and the film material to be polished is too strong, the polishing rate of the film material to be polished may be reduced, thereby causing problems in terms of processing efficiency and polishing flatness. Therefore, it is a very important factor to control the electrical properties between the polishing pad, the polishing slurry, and the film material to be polished to an appropriate level.

[0041] Zeta potential generally refers to the physical property exhibited by particles in a suspension. There are two types of liquid layers around the particles: an inner region (dry layer: electronic layer) where ions form a strong boundary and an outer region (diffusion layer) where ions are weakly bound. The outer region (diffusion layer) is a region where ions and particles exist stably within a theoretical boundary. For example, if a particle moves, the ions in the inner region move within a specific boundary. On the other hand, ions present outside a specific boundary move independently of the particles, like a giant dispersant. The potential at this boundary is the zeta potential. Polishing slurry has its own zeta potential as a suspension in which polishing particles are dispersed.

[0042] Since the polishing pad is not in a suspended state as a cured resin, it does not have a generally defined zeta potential. In the embodiment, the surface zeta potential is designed as an index for representing the polishing performance of the polishing pad, and the surface zeta potential of the polishing pad can be defined by the above-mentioned relational formula 1 in association with a standard composition in a suspended state having a specific zeta potential.

[0043] In the following, reference will be made to Figure 1 The surface zeta potential of the polishing pad is described in more detail.

[0044] Figure 1 Schematic diagram showing the surface zeta potential of the polishing pad. Figure 1 The polishing pad (100) may include a polishing layer (10). The polishing layer (10) may include a polishing surface (11) for polishing a film material to be polished that is in direct or indirect contact with the polishing pad (100). The polishing pad (100) may be composed of a single-layer polishing layer (10), or may have a multi-layer structure including the polishing layer (10). Figure 1 The polishing pad (100) according to the embodiment may include an adhesive layer (30) and a buffer layer (20) on one side of the polishing layer (10), but is not limited thereto.

[0045] When a predetermined standard composition having its own zeta potential is provided on the polishing surface (11) of the polishing pad (100), the polishing pad (100) has a fixed layer (110), an ion diffusion layer (120) and a sliding surface (130). The fixed layer (110) is a layer formed by particles in the standard composition being stably present on the polishing surface (11). It is a region corresponding to an inner region (dry layer: electron layer) in the zeta potential generally defined for a suspension. Compared to the fixed layer (110), the ion diffusion layer (120) is a region where particles in the standard composition are relatively weakly bonded to the polishing surface (11). It is the gap between the polished surface (11) The ion diffusion layer (120) corresponds to a region which is usually a suspension. The sliding plane (130) is a region corresponding to a specific boundary in the zeta potential generally defined for a suspension.

[0046] In an embodiment, the surface zeta potential of the polishing pad according to Relation 1 is defined as the sum of the negative (-) value of the zeta potential value of the fixed layer (110) and the zeta potential value of the corresponding standard composition. Figure 1 As shown, if the charge of the fixed layer (110) is positive (+), the polishing surface adjacent to the fixed layer (110) will have a negative (-) charge. Therefore, when deriving the surface zeta potential of the polishing pad, the value obtained by applying (-) to the zeta potential value of the fixed layer (110) is used. When the change in the zeta potential of the particles in the standard composition with respect to the distance from the polishing surface is plotted as a graph, the zeta potential of the fixed layer (110) is defined as the value of the Y intercept of the graph. The zeta potential of the particles is measured by electrophoretic mobility.

[0047] If the polishing pad satisfies specific conditions related to the surface zeta potential according to Relationship 1, that is, the conditions according to Relationship 2, reliable polishing performance can be achieved in terms of the interaction between the polishing pad, the polishing slurry to be used in the process using the polishing pad, and the film material to be polished.

[0048] The first composition and the second composition are compositions having different hydrogen ion concentrations (pH). The surface zeta potential of the polished surface of each composition is different. The ratio of the first surface zeta potential (PZ1) obtained from the first composition to the second surface zeta potential (PZ2) obtained from the second composition satisfies a predetermined range, which has a technical significance in that when the polishing pad is applied to an actual process, it is possible to simultaneously perform polishing of film materials of different materials with excellent performance.

[0049] Meanwhile, in another embodiment of the present invention, the polishing pad includes a polishing layer, wherein when polishing is performed using a first composition having a hydrogen ion concentration (pH) of 8 to 12, the polishing surface of the polishing layer has a first surface zeta potential (PZ1), and the first surface zeta potential is the value of the surface zeta potential of the polishing surface obtained by the above-mentioned equation 1 for the first composition; when polishing is performed using a third composition having a hydrogen ion concentration (pH) of 7.5 to 9.5, the polishing surface of the polishing layer has a third surface zeta potential (PZ3), and the third surface zeta potential (PZ3) is the value of the surface zeta potential of the polishing surface obtained by the above-mentioned equation 1 for the third composition; and at least one of the first surface zeta potentials (PZ1) and at least one of the third surface zeta potentials (PZ3) satisfy the following equation 3:

[0050] [Equation 3]

[0051]

[0052] The first composition and the third composition are compositions having different hydrogen ion concentrations (pH) from each other. The surface zeta potential of the polished surface of each composition is different from each other. The ratio of the first surface zeta potential (PZ1) obtained from the first composition to the third surface zeta potential (PZ3) obtained from the third composition satisfying a predetermined range means that surface defects such as scratches and chatter marks can be minimized while achieving excellent polishing performance in various processes, such as batch and fine processing of oxide layers with a single polishing pad, and when the polishing pad is applied to an actual process, a single polishing pad is applied continuously or discontinuously to each process step in the above environment.

[0053] In another embodiment of the present invention, the polishing pad includes a polishing layer, wherein when polishing is performed using a first composition having a hydrogen ion concentration (pH) of 8 to 12, specifically not greater than 9.5 to 12, the polishing surface of the polishing layer has a first surface zeta potential (PZ1), which is the value of the surface zeta potential of the polishing surface obtained by the above relationship 1 for the first composition; when polishing is performed using a second composition having a hydrogen ion concentration (pH) of 2 to 6, the polishing surface of the polishing layer has a second surface zeta potential (PZ2), which is the value of the surface zeta potential of the polishing surface obtained by the above relationship 1 for the second composition. The polishing layer has a third surface zeta potential (PZ3) when polishing is performed using a third composition having a hydrogen ion concentration (pH) of 7.5 to 9.5, and the third surface zeta potential (PZ3) is the value of the surface zeta potential of the polishing surface obtained by the above relationship 1 for the third composition; and at least one of the first surface zeta potentials (PZ1), at least one of the second surface zeta potentials (PZ2), and at least one of the third surface zeta potentials (PZ3) satisfies the following relationship 4:

[0054] [Equation 4]

[0055]

[0056] The first composition, the second composition and the third composition are compositions having different hydrogen ion concentrations (pH). The surface zeta potential of the polishing surface of each composition is different. The product (PZ1×PZ2) of the first surface zeta potential (PZ1) derived from the first composition and the second surface zeta potential (PZ2) derived from the second composition and the ratio (PZ1×PZ2 / PZ3, Relationship 4) of the third surface zeta potential (PZ3) derived from the third composition satisfying the predetermined range means that when the polishing pad is applied to an actual process, polishing using different types of polishing slurries can be performed simultaneously with excellent performance.

[0057] Specifically, the advantage of a polishing pad that satisfies Relationship 4 is that it is able to achieve a range of excellent polishing performances in polishing environments using different types of polishing slurries (particularly silica and ceria slurries) to minimize surface defects such as scratches and chatter marks, and to continuously or discontinuously apply a single polishing pad to various process steps using silica and ceria slurries.

[0058] In another embodiment of the present invention, the polishing pad includes a polishing layer, wherein when polishing is performed using a first composition having a hydrogen ion concentration (pH) of 8 to 12, specifically greater than 9.5 to 12, the polishing surface of the polishing layer has a first surface zeta potential (PZ1), which is the value of the surface zeta potential of the polishing surface obtained by the above relationship 1 for the first composition; when polishing is performed using a second composition having a hydrogen ion concentration (pH) of 2 to 6, the polishing surface of the polishing layer has a second surface zeta potential (PZ2), which is the value of the surface zeta potential of the polishing surface obtained by the above relationship 1 for the second composition. When polishing is performed using a third composition having a hydrogen ion concentration (pH) of 7.5 to 9.5, the polished surface of the polishing layer has a third surface zeta potential (PZ3), the third surface zeta potential (PZ3) being the value of the surface zeta potential of the polished surface obtained by the above-mentioned relational expression 1 for the third composition; and at least one of the first surface zeta potentials (PZ1), at least one of the second surface zeta potentials (PZ2), and at least one of the third surface zeta potentials (PZ3) satisfy the following relational expression 5:

[0059] [Equation 5]

[0060]

[0061] The ratio of the difference (PZ2-PZ1) between the second surface zeta potential (PZ2) obtained from the second composition and the first surface zeta potential (PZ1) obtained from the first composition to the difference (PZ2-PZ3) between the second surface zeta potential (PZ2) obtained from the second composition and the third surface zeta potential (PZ3) obtained from the third composition ((PZ2-PZ1) / (PZ2-PZ3)) satisfies the predetermined range, which means that when the polishing pad is applied to an actual process, it is capable of simultaneously polishing with excellent performance in an environment of different polishing slurries or using different types of polishing slurries.

[0062] Specifically, the advantage of a polishing pad satisfying equation 5 is that it is able to achieve excellent polishing performance in different polishing environments, especially in acidic and alkaline polishing environments, or using silica and ceria slurries to minimize surface defects such as scratches and chatter marks, and to apply a single polishing pad continuously or discontinuously to various process steps in the above-mentioned environments.

[0063] If the polishing pad satisfies predetermined conditions related to the surface zeta potential according to equation 1, that is, conditions according to one or more of equations 2 to 5, reliable polishing performance can be achieved in terms of the interaction between the polishing pad, the polishing slurry to be used in the process using the polishing pad, and the film material to be polished.

[0064] In an embodiment, the first composition may have a hydrogen ion concentration (pH) of 8 to 12, such as 9 to 12, such as greater than 9.5 to 12, such as 9 to 11, such as 10 to 12, such as 10 to 11.5, such as 10.5 (±0.5).

[0065] In embodiments, the second composition may have a pH of 2 to 6, such as 2 to 5, such as 3 to 6, such as 3 to 5, such as 4 (± 0.5).

[0066] In an embodiment, the third composition can have a hydrogen ion concentration (pH) of 7.5 to 9.5, such as 7.8 to 9.3, such as 7.8 to 9, such as 8.5 (±0.5).

[0067] The first composition and the third composition may be alkaline slurries, and the second composition may be an acidic slurry. Although the first composition and the third composition are alkaline slurries, the first composition includes silicon dioxide particles, and the third composition includes cerium dioxide particles. They may differ from each other in pH value, for example, about 0.5 to 4.5, for example, about 0.5 to 4, for example, about 1 to 3.5, for example, about 1 to 3.

[0068] In the polishing pad according to the embodiment, the zeta potential of the fixed layer of Relationship 1 may vary according to the chemical and physical properties of the polishing layer of the polishing pad and the type of the standard composition. When the first zeta potential of the fixed layer measured for the polishing surface of the polishing pad using the first composition is IZ1, when the second zeta potential of the fixed layer measured for the polishing surface of the polishing pad using the second composition is IZ2, and when the third zeta potential of the fixed layer measured for the polishing surface of the polishing pad using the third composition is IZ3, the zeta potential IZ1 of the fixed layer of the first composition may be about +5 mV to about +30 mV, the zeta potential IZ2 of the fixed layer of the second composition may be about -5 mV to about +15 mV, and the zeta potential of the fixed layer of the third composition IZ3 may be about -15 mV to about +10 mV.

[0069] Specifically, the first zeta potential (IZ1) of the fixed layer may be about +5mV to about +30mV, for example, about +8mV to about +28mV, for example, about +10mV to about +25mV, for example, about +11mV to about +23mV, for example, about +15mV to about +25mV.

[0070] The second zeta potential (IZ2) of the fixed layer may be about -5 mV to about +15 mV, such as about -2 mV to about +12 mV, such as about -1 mV to about +8 mV, such as about -0.7 mV to about +6 mV, such as about -0.7 mV to about +4 mV.

[0071] The third zeta potential (IZ3) of the fixed layer may be 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 about -8.8 mV to about +6 mV.

[0072] In an embodiment, the first composition may include silica particles having an average particle size of about 130 nm to about 160 nm and having a zeta potential of -50 mV to -30 mV, the second composition may include silica particles having an average particle size of about 30 nm to about 50 nm and having a zeta potential of +10 mV to +30 mV, and the third composition may include cerium dioxide particles having an average particle size of about 130 nm to about 170 nm, specifically, about 130 nm to about 160 nm, and having a zeta potential of -55 mV to -35 mV.

[0073] The zeta potential of each of the first composition, the second composition, and the third composition can be determined by its components and their contents. Any three compositions containing the same components in the same contents will have the same zeta potential value. However, any three compositions having the same zeta potential value do not necessarily contain the same components in the same contents.

[0074] In an embodiment, the first composition may include fumed silica particles, the second composition may include colloidal silica particles, and the third composition may include ceria particles, such as wet ceria particles.

[0075] In a polishing pad having a polishing surface, the surface zeta potential of the polishing surface satisfies at least one of the above-mentioned relationships 2 to 5 for a first composition comprising fumed silica particles, a second composition comprising colloidal silica particles, and a third composition comprising cerium dioxide particles, and each composition has a zeta potential as described above, with the advantage that a series of excellent polishing performances can be achieved in a polishing environment using different types of polishing slurries, surface defects such as scratches and chatter marks can be minimized, a single polishing pad can be continuously or discontinuously applied to various process steps in the above-mentioned environment, and excellent polishing performance of all film materials can be ensured.

[0076] In an embodiment, the fumed silica particles may have an average particle size of 130 nm to 160 nm, such as 140 nm to 160 nm, such as 150 (± 5) nm. In an embodiment, the colloidal silica particles may have an average particle size of 30 nm to 50 nm, such as 30 nm to 45 nm, such as 40 nm (± 5) nm. In an embodiment, the cerium oxide particles may have an average particle size of 130 nm to 170 nm, such as 130 nm to 160 nm, such as 140 nm to 160 nm, such as 150 (± 5) nm. The average particle size is nm.

[0077] According to an embodiment of the present invention, the first composition may be a composition having a zeta potential of -50 mV to -30 mV. The zeta potential of the first composition can be, for example, -50mV to -35mV, for example -50mV to -40mV, for example -48mV to -35mV, for example -48mV to -40mV, for example -47mV to -35mV, for example -47mV to -40mV, for example -46mV to -38mV, for example -46mV to -40mV, for example -45mV to -38mV, for example -45mV to -40mV, for example -44mV to -38mV, for example -44mV to -40mV, for example -43mV to -38mV, for example -43mV to -40mV, for example -42mV to -38mV, for example -42mV to -40mV, for example -42mV to -41mV.

[0078] The second composition may be a composition having a zeta potential of +10 mV to +30 mV. The zeta potential of the second composition may be, for example, +15 mV to +30 mV, for example, +20 mV to +30 mV, for example, +20 mV to +28 mV, for example, +20 mV to +27 mV, for example, +20 mV to +26 mV, for example, +20 mV to +25 mV, for example, +20 mV to +24 mV, for example, +20 mV to +23 mV, for example, +21 mV to +23 mV.

[0079] The third composition may be a composition having a zeta potential of -55 mV to -35 mV. The zeta potential of the third composition may be, for example, -50 mV to -35 mV, for example, -50 mV to -40 mV, for example, -50 mV to -43 mV, for example, -48 mV to -43 mV, for example, -47 mV to -43 mV, for example, -46 mV to -43 mV, for example, -46 mV to -44 mV.

[0080] In a polishing pad having a polishing surface, the surface zeta potential of the polishing surface satisfies the condition of Relationship 2 for a first composition including fumed silica particles having the above-mentioned average particle size and a second composition including colloidal silica particles having the above-mentioned average particle size, and each composition has the above-mentioned zeta potential, which has an advantage in that when a polishing process is continuously or discontinuously performed on an object to be polished having film substances of different materials, especially an object to be polished having an oxide layer and an object to be polished having a tungsten (W) layer, excellent polishing performance for all film substances can be ensured.

[0081] In addition, in a polishing pad having a polishing surface, the surface zeta potential of the polishing surface satisfies the condition of Relationship 3 for a first composition including fumed silica particles having the above-mentioned average particle size and a third composition including cerium dioxide particles having the above-mentioned average particle size, and each composition has the above-mentioned zeta potential, there is an advantage in that when bulk processing and fine processing are continuously or discontinuously performed on an object to be polished having an oxide layer, excellent polishing performance can be ensured in both batch and fine processing of the oxide layer.

[0082] In addition, in a polishing pad having a polishing surface, the surface zeta potential of the polishing surface satisfies the condition of Relationship 4 for a first composition including gas-phase silica particles having the above-mentioned average particle size, a second composition including colloidal silica particles having the above-mentioned average particle size, and a third composition including cerium dioxide particles having the above-mentioned average particle size, and each composition has the zeta potential as described above, with the advantage that when respective polishing processes using silica slurry and cerium dioxide slurry are performed continuously or discontinuously, excellent polishing performance of the oxide layer, the tungsten layer or both can be ensured without surface defects.

[0083] In addition, in a polishing pad having a polishing surface, the surface zeta potential of the polishing surface is A first composition comprising silica particles, a second composition comprising colloidal silica particles, and a second composition comprising cerium oxide particles The third composition satisfies the condition of Relationship 5, and each composition has a zeta potential as described above, with the advantage that excellent polishing performance can be achieved in different polishing environments, specifically, when the slurry environment is acidic and alkaline, or when silica slurry and cerium dioxide slurry are used to minimize surface defects such as scratches and chatter marks, and a single polishing pad can be applied continuously or discontinuously to various process steps in the above environment.

[0084] The zeta potentials of the first composition, the second composition, and the third composition each have a fixed value in one of the above numerical ranges. As a result, the first surface zeta potential (PZ1), the second surface zeta potential (PZ2), and the third surface zeta potential (PZ3) derived from the first composition, the second composition, and the third composition also each have a fixed value.

[0085] PZ1 may be, 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.

[0086] PZ2 may be, for example, +10 mV to +30 mV, such as +12 mV to +28 mV, +14 mV to +26 mV, +15 mV to +26 mV, +16 mV to +26 mV, +16 mV to +25 mV, or +16 mV to +23 mV.

[0087] PZ3 may be, for example, -60 mV to -30 mV, for example, -58 mV to -30 mV, for example, -56 mV to -32 mV, for example, -55 mV to -32 mV, for example, -55 mV to -35 mV, for example, -54 mV to -35 mV, for example, -52 mV to -35 mV.

[0088] In the polishing pad according to the embodiment, as long as at least one PZ1 value and at least one PZ2 value satisfy the condition of Relational Formula 2, the advantages of the present invention can be achieved even if another PZ1 value and another PZ2 value do not satisfy the condition of Relational Formula 2. That is, the condition of Relational Formula 2 is that the ratio (PZ1 / PZ2) of at least one of the first surface zeta potentials (PZ1) of the polishing surface to at least one of the second surface zeta potentials (PZ2) is in the range of -20 to 0. PZ1 / PZ2 may be, for example, -10 to 0, for example, -5 to 0, for example, -4 to 0, for example, -3 to 0.

[0089] In a polishing pad according to another embodiment, as long as at least one PZ1 value and at least one PZ3 value satisfy the condition of Relationship 3, the advantages of the present invention can be achieved even if another PZ1 value and another PZ3 value do not satisfy the condition of Relationship 3. That is, the condition of Relationship 3 is that the ratio (PZ1 / PZ3) of at least one of the first surface zeta potentials (PZ1) of the polishing surface to at least one of the third surface zeta potentials (PZ3) is in the range of 1 to 5. PZ1 / PZ3 can be, for example, greater than 1 to 5, for example, greater than 1 to 3, for example, greater than 1 to 2, for example, 1.05 to 1.8, for example, 1.05 to 1.5.

[0090] In a polishing pad according to yet another embodiment, as long as at least one of the first surface zeta potentials (PZ1), at least one of the second surface zeta potentials (PZ2), and at least one of the third surface zeta potentials (PZ3) satisfy the condition of Relationship 4, the advantages of the present invention can be achieved even if another PZ1 value, another PZ2 value, and another PZ3 value do not satisfy the condition of Relationship 4. That is, the condition of Relationship 4 is that the product of at least one first surface zeta potential (PZ1) and at least one second surface zeta potential (PZ2) of the polishing surface is equal to or less than the product of at least one third surface zeta potential (PZ3). The ratio of potential (PZ3) (PZ1× PZ2 / PZ3) ratio (PZ1×PZ2) is in the range of 1.1 to 50. 3 can be, for example, 5 to 50, for example, 10 to 50, for example, 15 to 40, for example, 17 to 35.

[0091] In PZ1×PZ2 / PZ3, since PZ1 and PZ2 refer to surface zeta potential values ​​derived from a composition (first composition or second composition) containing the same type of silica particles (fumed silica particles or colloidal silica particles), and PZ3 refers to a surface zeta potential value derived from a composition containing ceria particles, PZ1×PZ2 / PZ3 may represent a ratio of a surface zeta potential value derived from a composition containing silica particles to a surface zeta potential value derived from a composition containing ceria particles. The advantage of a polishing pad having a polishing surface satisfying Relationship 4 is that a range of excellent polishing performances can be achieved in a polishing environment using different types of polishing slurries (particularly silica and ceria slurries) to minimize surface defects such as scratches and chatter marks, and a single polishing pad can be applied continuously or discontinuously to various process steps using silica and ceria slurries.

[0092] In the polishing pad according to still another embodiment, as long as at least one of the first surface zeta potentials (PZ1), at least one of the second surface zeta potentials (PZ2), and at least one of the third surface zeta potentials (PZ3) satisfies the condition of Relational Expression 5, the advantages of the present invention can be achieved even if another PZ1 value, another PZ2 value, and another PZ3 value do not satisfy the condition of Relational Expression 5. That is, the condition of Relational Expression 5 is that the ratio ((PZ2-PZ1) / (PZ2-PZ3)) of the difference (PZ2-PZ1) between at least one of the second surface zeta potentials (PZ2) and at least one of the first surface zeta potentials (PZ1) of the polishing surface and the difference (PZ2-PZ3) between at least one of the second surface zeta potentials (PZ2) and at least one of the third surface zeta potentials (PZ3) is in the range of 1 to 5. (PZ2-PZ1) / (PZ2-PZ3) can be, for example, greater than 1 to 5, for example, 1.02 to 4, for example, 1.02 to 3, for example, 1.02 to 2.

[0093] At the same time, the difference (PZ2-PZ1) between at least one of the second surface zeta potentials (PZ2) and at least one of the first surface zeta potentials (PZ1) can be 50mV to 100mV. PZ2-PZ1 can be, for example, 60mV to 100mV, for example, 65mV to 100mV, for example, 65mV to 95mV, or for example, 65mV to 90mV.

[0094] The difference (PZ2-PZ3) between at least one of the second surface zeta potentials (PZ2) and at least one of the third surface zeta potentials (PZ3) may be 40 mV to 80 mV. PZ2-PZ3 may be, for example, 45 mV to 75 mV, for example, 50 mV to 75 mV, for example, 55 mV to 75 mV, or for example, 64 mV to 75 mV.

[0095] Since PZ2-PZ1 and PZ2-PZ3 satisfy the above range, when the polishing pad is applied to the actual process, it is possible to simultaneously perform polishing in an environment with different compositions (polishing slurries) or using different types of polishing slurries with excellent performance, and it is possible to improve surface defects such as scratches and chatter marks that appear on the oxide layer or tungsten layer.

[0096] In an embodiment, when the oxide layer is polished using the first composition, the polishing rate (OR1) of the polishing surface of the polishing pad may be to less than For example, OR1 can be to less than For example to less than For example to For example to For example, greater than to For example to

[0097] When the second composition is used to polish the tungsten layer, the polishing rate (WR2) of the polishing surface of the polishing pad may be to For example, WR2 can be to For example to For example to For example to

[0098] When the third composition is used to polish the oxide layer, the polishing rate (OR3) of the polishing surface of the polishing pad may be to OR3 may be, for example arrive For example arrive For example arrive For example arrive

[0099] In an embodiment, the polishing pad can have a ratio of OR1 to WR2 (OR1 / WR2) of 3.0 to 4.5, eg, 3.2 to 4.2, eg, 3.5 to 4.0, eg, 3.6 to 3.8, eg, 3.65 to 3.78.

[0100] OR1 and WR2 may be factors for determining polishing performance, in particular, indirect indicators of whether the polishing rate of the polishing pad for the oxide layer and the tungsten (W) layer reaches a desired level. The polishing performance may be evaluated by comprehensively considering various factors such as polishing selectivity and structural defects and polishing rate. Since the polishing pad according to the embodiment has a polishing surface that meets the requirements for OR1 and WR2, an appropriate polishing rate may be achieved while achieving the advantage of minimizing structural defects such as recesses, scratches, and chatter marks.

[0101] In another embodiment, the polishing pad can have a ratio of OR1 to OR3 (OR1 / OR3) of 1.0 to 1.5, such as 1.1 to 1.4, such as 1.12 to 1.30, such as 1.12 to 1.17, such as 1.24 to 1.30.

[0102] OR1 and OR3 can be indirect indicators for determining whether the factors of the polishing rate of the polishing pad reach the desired level in various processes (e.g., batch and fine processing of oxide layers using a polishing pad using a silicon dioxide polishing slurry and / or a ceria polishing slurry). The polishing performance can be evaluated by comprehensively considering various factors such as polishing selectivity and structural defects and polishing rate. Since the polishing pad according to the embodiment has a polishing surface that meets the requirements for OR1 and OR3, an appropriate polishing rate can be achieved, and at the same time, the advantage of minimizing structural defects such as recesses, scratches, and chatter marks can be achieved.

[0103] In yet another embodiment, the ratio of the product of OR1 and WR2 to OR3 (OR1×WR2 / OR3) may be 800 to 1300, such as 850 to 1250, such as 890 to 1200, such as 890 to 1020, or such as 930 to 1020.

[0104] OR1, WR2, and OR3 may be factors for determining polishing performance, particularly indirect indicators of whether the polishing rate of the polishing pad for the oxide layer and the tungsten (W) layer reaches a desired level. The polishing performance may be evaluated by comprehensively considering various factors such as polishing selectivity and structural defects as well as the polishing rate. Since the polishing pad according to the embodiment has a polishing surface that meets the requirements for OR1, WR2, and OR3, an appropriate polishing rate may be achieved while achieving the advantage of minimizing structural defects such as recesses, scratches, and chatter marks.

[0105] In yet another embodiment, the difference between WR2 and OR1 (WR2-OR1) and the difference between WR2 and OR3 (WR2-OR3) The ratio (WR2-OR1) / (WR2-OR3) may be 1 to 2, such as 1 to 1.8, such as 1 to 1.6, such as 1 to 1.5, or such as 1.1 to 1.5.

[0106] OR1, WR2, and OR3 may be factors for determining polishing performance, particularly indirect indicators of whether the polishing rate of the polishing pad for the oxide layer and the tungsten (W) layer reaches a desired level. The polishing performance may be evaluated by comprehensively considering various factors such as polishing selectivity and structural defects as well as the polishing rate. Since the polishing pad according to the embodiment has a polishing surface that meets the requirements for OR1, WR2, and OR3, an appropriate polishing rate may be achieved while achieving the advantage of minimizing structural defects such as recesses, scratches, and chatter marks.

[0107] In an 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 may be 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, about 14 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 diameters of the plurality of pores by the number of pores.

[0108] In an embodiment, a polishing pad may include a polishing layer including a cured product formed of a composition including a polyurethane-based prepolymer, a curing agent, and a foaming agent.

[0109] Each component included in the composition will be described in detail below.

[0110] "Prepolymer" generally refers to a polymer with a relatively low molecular weight in which the degree of polymerization is adjusted to an intermediate level so as to facilitate molding in the process of producing a cured product. The prepolymer can be formed into a final cured product alone or after reacting with another polymerizable compound.

[0111] In an embodiment, the polyurethane-based prepolymer may be prepared by reacting an isocyanate compound with a polyol.

[0112] The isocyanate compound used for preparing the polyurethane-based prepolymer may be one selected from the group consisting of aromatic diisocyanate, aliphatic diisocyanate, alicyclic diisocyanate, or a combination thereof.

[0113] For example, the isocyanate compound may include one selected from the group consisting of 2,4-toluene diisocyanate (2,4-TDI), 2,6-toluene diisocyanate (2,6-TDI), naphthalene-1,5-diisocyanate, p-phenylene diisocyanate, toluene diisocyanate, 4,4"-diphenylmethane diisocyanate, hexamethylene diisocyanate, dicyclohexylmethane diisocyanate, isophorone diisocyanate, and combinations thereof.

[0114] The polyol is a compound containing at least two or more hydroxyl groups (-OH) per molecule. For example, it may include one selected from the group consisting of polyether polyol, polyester polyol, polycarbonate polyol, acrylic polyol, and combinations thereof.

[0115] For example, the polyol may include one selected from the group consisting of polytetramethylene ether glycol, polypropylene glycol ether, ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,2-butylene glycol, 1,3-butylene glycol, 2-methyl-1,3-propylene glycol, 1,4-butylene glycol, neopentyl glycol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, 1,6-hexanediol, diethylene glycol, dipropylene glycol, tripropylene glycol, and combinations thereof.

[0116] The polyol may have a weight average molecular weight (Mw) of 100 g / mol to 3000 g / mol. For example, the polyol may have A weight average molecular weight (Mw) of about 100 g / mol to about 3000 g / mol, for example, about 100 g / mol to about 2000 g / mol , for example, from about 100 g / mol to about 1800 g / mol.

[0117] In an embodiment, the polyol may include a low molecular weight polyol having a weight average molecular weight (Mw) of about 100 g / mol to less than about 300 g / mol and a high molecular weight polyol having a weight average molecular weight (Mw) of about 300 g / mol to about 1800 g / mol.

[0118] The polyurethane-based prepolymer may have a weight average molecular weight (Mw) of 500 to 3000 g / mol. The polyurethane-based prepolymer may have a weight average molecular weight (Mw) of, for example, about 1000 to about 2000 g / mol, for example, about 1000 to about 1500 g / mol.

[0119] In an embodiment, the isocyanate compound for preparing the polyurethane-based prepolymer may include an aromatic diisocyanate compound, and the aromatic diisocyanate compound may include, for example, 2,4-toluene diisocyanate (2,4-TDI) and 2,6-toluene diisocyanate (2,6-TDI). The polyol compound for preparing the polyurethane-based prepolymer may include polytetramethylene ether glycol (PTMEG) and diethylene glycol (DEG).

[0120] In another embodiment, the isocyanate compound for preparing the polyurethane-based prepolymer may include an aromatic diisocyanate compound and an alicyclic diisocyanate compound. For example, the aromatic diisocyanate compound may include 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 polyurethane-based prepolymer may include polytetramethylene ether glycol (PTMEG) and diethylene glycol (DEG).

[0121] The polyurethane-based prepolymer may have an isocyanate end group content (NCO %) of about 5 wt % to about 11 wt %, such as about 5 wt % to about 10 wt %, such as about 5 wt % to about 8 wt %, such as about 8 wt % to about 10 wt %.

[0122] The isocyanate terminal group content (NCO%) of the polyurethane-based prepolymer can be designed by comprehensively adjusting the types and contents of the isocyanate compounds and polyol compounds used to prepare the polyurethane-based prepolymer, the process conditions such as temperature, pressure and time in the process for preparing the polyurethane-based prepolymer, and the types and contents of additives used in the preparation of the polyurethane-based prepolymer.

[0123] If the NCO% of the polyurethane-based prepolymer satisfies the above range, the reaction rate, reaction time and final cured structure in the subsequent reaction between the polyurethane-based prepolymer and the curing agent can be adjusted in a manner favorable to polishing performance from the viewpoint of the use and purpose of the final polishing pad.

[0124] In an embodiment, the polyurethane-based prepolymer may have an isocyanate terminal group content (NCO%) of about 8 wt % to about 10 wt %, for example, about 8 wt % to about 9.4 wt %. If the NCO% of the polyurethane-based prepolymer is less than the above range, the first surface zeta potential, the second surface zeta potential, and the third surface zeta potential, which are electrical properties based on the chemical hardening structure in the polishing pad, may be achieved, so that the desired polishing performance in terms of polishing rate and flatness cannot be achieved, and there may be a problem in that the life of the polishing pad is reduced due to an excessive increase in the cutting pad rate. On the other hand, If If NCO% exceeds the above range, surface defects such as scratches and chatter marks on the semiconductor substrate May increase.

[0125] The curing agent is a compound for chemically reacting with the polyurethane-based prepolymer to form a final cured structure in the polishing layer. For example, it may include 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.

[0126] For example, the curing agent may include one selected from the group consisting of 4,4′-methylenebis(2-chloroaniline) (MOCA), diethyltoluenediamine (DETDA), diaminodiphenylmethane, dimethylthiotoluenediamine (DMTDA), propylene glycol bis-p-aminobenzoate, methylenebismethylanthracene, diaminodiphenyl sulfone, m-phenylenediamine, isophoronediamine, ethylenediamine, diethylenetriamine, triethylenetetramine, polypropylenediamine, polypropylenetriamine, bis(4-amino-3-chlorophenyl)methane, and combinations thereof.

[0127] Based on 100 parts by weight of the polyurethane-based prepolymer, the curing agent may be included in an amount of about 18 parts by weight to about 27 parts by weight, such as about 19 parts by weight to about 26 parts by weight, such as about 20 parts by weight to about 26 parts by weight. If the curing agent content satisfies the above range, it may be more advantageous for achieving a desired surface zeta potential ratio of the polishing pad.

[0128] In an embodiment, the curing agent may include 4,4"-methylenebis(2-chloroaniline) or dimethylthiotoluenediamine. The content of the curing agent may be about 21 parts by weight to about 26 parts by weight based on 100 parts by weight of the polyurethane-based prepolymer. Thus, according to the reaction between the polyurethane-based prepolymer and the curing agent, the cured structure of the polyurethane in the polishing layer may generate electrical properties based on chemical characteristics. Such electrical properties are beneficial for achieving the polishing performance of the polishing pad within a desired range.

[0129] The foaming agent is a component for forming a pore structure in the polishing layer. It may include one selected from the group consisting of a solid-phase foaming agent, a gas-phase foaming agent, a liquid-phase foaming agent, and a combination thereof. In an embodiment, the foaming agent may include a solid-phase foaming agent, a gas-phase foaming agent, and a combination thereof.

[0130] The solid-phase foaming agent may have an average particle size of 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. The average particle size of the solid foaming agent may refer to the average particle size of the heat-expandable particles when the solid-phase foaming agent is the heat-expandable particles described below, and the average particle size of the particles after expansion by heat or pressure when the solid-phase foaming agent is the unexpanded particles described below.

[0131] The solid phase foaming agent may include expandable particles. Expandable particles are particles having the property of being expandable by heat or pressure. The size of the final polishing layer may be determined by the heat or pressure applied in the process of preparing the polishing layer. Expandable particles may include heat-expandable particles, unexpanded particles, or a combination thereof. Heat-expandable particles are particles pre-expanded by heat. They refer to particles that have little or no size change due to heat or pressure applied in the process of preparing the polishing layer. Unexpanded particles are particles that have not been pre-expanded by heat. They refer to particles whose final size is determined when expanded by heat or pressure applied in the process of preparing the polishing layer.

[0132] The expandable particles may include a resin shell; and an expansion inducing component encapsulated within the shell.

[0133] For example, the shell may comprise a thermoplastic resin. The thermoplastic resin may be selected from the group consisting of ethylidene chloride copolymers, acrylic At least one of the group consisting of acrylonitrile-based copolymers, methacrylonitrile-based copolymers and acrylic acid-based copolymers.

[0134] The expansion inducing component may include one selected from the group consisting of hydrocarbon compounds, fluorochloro compounds, tetraalkylsilane compounds, and combinations thereof.

[0135] Specifically, the hydrocarbon may include one selected from the group consisting of ethane, ethylene, propane, propylene, n-butane, isobutane, n-butene, isobutylene, isobutylene, n-pentane, isopentane, neopentane, n-hexane, heptane, petroleum ether, and combinations thereof.

[0136] The fluorochloro compound may include one selected from the group consisting of trichlorofluoromethane (CCl3F), dichlorodifluoromethane (CCL2F2), chlorotrifluoromethane (trichloromethane, CClF3), tetrafluoroethylene (tetrafluoroethylene, CClF2-CClF2) and combinations thereof.

[0137] The tetraalkylsilane compound may include one selected from the group consisting of tetramethylsilane, trimethylethylsilane, trimethylisopropylsilane, trimethyl-N-propylsilane, and combinations thereof.

[0138] The solid phase foaming agent may optionally include particles treated with an inorganic component. For example, the solid phase foaming agent may include expandable particles treated with an inorganic component. In an embodiment, the solid phase foaming agent may include expandable particles treated with silicon dioxide (SiO2) particles. Treating the solid phase foaming agent with an inorganic component can prevent aggregation between multiple particles. In terms of the chemical, electrical and / or physical properties of the foaming agent surface, the solid phase foaming agent treated with an inorganic component may be different from a solid phase foaming agent that has not been treated with an inorganic component.

[0139] The solid phase foaming agent may be included in an amount of about 0.5 to about 10 parts by weight, such as about 1 to about 3 parts by weight, such as about 1.3 to about 2.7 parts by weight, such as about 1.3 to about 2.6 parts by weight, based on 100 parts by weight of the polyurethane-based prepolymer.

[0140] The type and content of the solid phase foaming agent can be designed according to the desired pore structure and physical properties of the polishing layer.

[0141] The gas phase foaming agent may include an inert gas. The gas phase foaming agent is added while the polyurethane-based prepolymer is reacted with the curing agent to serve as a component for forming cells.

[0142] The type of inert gas is not particularly limited as long as it is a gas that does not participate in the reaction between the polyurethane-based prepolymer and the curing agent. For example, the inert gas may include one selected from the group consisting of nitrogen (N2), argon (Ar), helium (He) and combinations thereof. Specifically, the inert gas may include nitrogen (N2) or argon (Ar).

[0143] The type and content of the gas-phase foaming agent can be designed according to the desired pore structure and physical properties of the polishing layer.

[0144] In an embodiment, the foaming agent may include a solid-phase foaming agent. For example, the foaming agent may be composed of a solid-phase foaming agent alone.

[0145] The solid phase foaming agent may include expandable particles, and the expandable particles may include thermal expansion particles. For example, the solid phase foaming agent may consist of thermal expansion particles alone. If it consists of thermal expansion particles alone without unexpanded particles, the variability of the pore structure is reduced and the predictability is improved, thereby facilitating the achievement of uniform pore characteristics over the entire area of ​​the polishing layer.

[0146] In an embodiment, the thermal expansion particles may be particles having an average particle size of about 5 μm to about 200 μm. The average particle size of the thermally expandable particles can be 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, such as about 30 μm to about 70 μm, such as about 25 μm to 45 μm, such as about 40 μm to about 70 μm, such as about 40 μm to about 60 μm. The average particle size is defined as the D50 of the thermally expandable particles.

[0147] In one embodiment, the thermally expandable particles may have a particle size of about 30 kg / m 3 About 80kg / m 3 Density, for example, about 35 kg / m 3 About 80kg / m 3 , for example about 35kg / m 3 About 75kg / m 3 , for example about 38kg / m 3 About 72kg / m 3 , for example about 40kg / m 3 About 75kg / m 3 , for example about 40kg / m 3 About 72kg / m 3 .

[0148] In an embodiment, the solid phase foaming agent may include expandable particles that have not been treated with an inorganic component. For example, the solid phase foaming agent may be composed of expandable particles that have not been treated with an inorganic component. Since expandable particles that have not been treated with an inorganic component are used as a solid phase foaming agent, the chemical and electrical properties of the surface of the solid phase foaming agent may be advantageous for obtaining the desired surface zeta potential characteristics.

[0149] In an embodiment, the foaming agent may include a gas phase foaming agent. For example, the foaming agent may include a solid phase foaming agent and a gas phase foaming agent. The details of the solid phase foaming agent are as described above.

[0150] The gas phase blowing agent may include nitrogen.

[0151] The gas phase blowing agent can be fed through a predetermined feeding line while the polyurethane-based prepolymer, the solid phase blowing agent and the curing agent are mixed. The feeding rate of the gas phase blowing agent is about 0.8 liters / minute to about 2.0 liters / minute, such as about 0.8 liters / minute to about 1.8 liters / minute, such as about 0.8 liters / minute to about 1.7 liters / minute, such as about 1.0 liters / minute to about 2.0 liters / minute, such as about 1.0 liters / minute to about 1.8 liters / minute, such as about 1.0 liters / minute to about 1.7 liters / minute.

[0152] The composition for preparing the polishing layer may also include other additives such as surfactants and reaction rate controllers. Names such as "surfactant" and "reaction rate controller" are arbitrary names based on the main role of the substance. Each substance does not necessarily perform only the function limited to the role defined by the name.

[0153] The surfactant is not particularly limited as long as it plays a role in preventing pores from agglomerating and overlapping each other. For example, the surfactant may include a silicone-based surfactant.

[0154] Based on the polyurethane-based prepolymer of 100 weight parts, the consumption of surfactant can be about 0.2 weight part to about 2 weight parts.Specifically, based on the polyurethane-based prepolymer of 100 weight parts, the consumption of surfactant can be about 0.2 weight part to about 1.9 weight parts, for example, about 0.2 weight part to about 1.8 weight parts, for example, about 0.2 weight part to about 1.7 weight parts, for example, about 0.2 weight part to about 1.6 weight parts, for example, about 0.2 weight part to about 1.5 weight parts, for example, 0.5 weight part to 1.5 weight parts.If the amount of surfactant is in the above range, the hole derived from gas-phase foaming agent can be stably formed and maintained in mold.

[0155] The reaction rate controller is used to promote or retard the reaction. Depending on the purpose, a reaction promoter, a reaction retarder or both can be used. The reaction rate controller can include a reaction promoter. For example, the reaction rate controller can be at least one reaction promoter selected from the group including a tertiary amine compound and an organometallic compound.

[0156] Specifically, the reaction rate control agent may include a compound selected from the group consisting of triethylenediamine, dimethylethanolamine, tetramethylAt least one of the group consisting of butanediamine, 2-methyl-triethylenediamine, dimethylcyclohexylamine, triethylamine, triisopropanolamine, 1,4-diazabicyclo (2,2,2) octane bis (2-methylaminoethyl) ether, trimethylaminoethylethanolamine, N,N,N,N,N "-pentamethyldiethylenetriamine, dimethylaminoethylamine, dimethylaminopropylamine, benzyldimethylamine, N-ethylmorpholine, N,N-dimethylaminoethylmorpholine, N,N-dimethylcyclohexylamine, 2-methyl-2-azanorbornane, dibutyltin dilaurate, stannous octoate, dibutyltin diacetate, dioctyltin diacetate, dibutyltin maleate, dibutyltin di-2-ethylhexanoate and dibutyltin dithiol. Specifically, the reaction rate controller may include at least one selected from the group consisting of benzyldimethylamine, N,N-dimethylcyclohexylamine and triethylamine.

[0157] Based on 100 parts by weight of the polyurethane-based prepolymer, the amount of the reaction rate controller can be about 0.05 parts by weight to about 2 parts by weight. Specifically, based on 100 parts by weight of the polyurethane-based prepolymer, the amount of the reaction rate controller can be about 0.05 parts by weight to about 1.8 parts by weight, such as about 0.05 parts by weight to about 1.7 parts by weight, such as about 0.05 parts by weight to about 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, 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 part by weight. If the reaction rate controller is used within the above content range, the curing reaction rate of the prepolymer composition can be appropriately controlled to form a polishing layer with a hole of a desired size and hardness.

[0158] In one embodiment, the content of the inorganic substance in the polishing layer may be about 5 ppm to about 500 ppm.

[0159] The inorganic substance 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.

[0160] The inorganic material can be derived from various sources. For example, the inorganic material can be derived from various additives, such as a foaming agent for preparing the polishing layer. Here, the additive used as the inorganic source can, for example, include one selected from the group consisting of a foaming agent, a surfactant, a reaction rate control agent, and a combination thereof.

[0161] The content of inorganic substances in the polishing layer can be designed within an appropriate range by using only one of the foaming agent and the additional additives and adjusting their type and content, or the content of inorganic substances in the polishing layer can be designed within an appropriate range by using both the foaming agent and the additional additives and adjusting their type and content.

[0162] The content of inorganic substances in the polishing layer may be about 5 ppm to about 500 ppm, such as about 5 ppm to about 400 ppm, such as about 8 ppm to about 300 ppm, such as about 220 ppm to about 400 ppm, such as about 5 ppm to about 180 ppm. In this case, the content of inorganic substances in the polishing layer can be measured by inductively coupled plasma atomic emission spectrometer (ICP) analysis.

[0163] The content of inorganic substances in the polishing layer may have a significant effect on the surface zeta potential of the polishing pad. If the content of inorganic substances satisfies the above range, the desired surface zeta potential of the polishing pad may be achieved within a predetermined range, specifically, the ratio of the surface zeta potential of the polishing pad according to the type of polishing slurry. If the content of inorganic substances in the polishing layer exceeds Pass If the concentration of zeta potential of the polishing pad is about 500 ppm, the composition of the polishing layer can be changed, so that the surface zeta potential of the polishing pad can be changed. In this case, the electrical correlation between the polishing layer and the polishing slurry in the process of manufacturing a semiconductor device may be changed in a direction that significantly increases surface defects (such as scratches and chatter marks) on the semiconductor substrate.

[0164] Hereinafter, a process for preparing the polishing pad will be described in detail.

[0165] In another embodiment according to the present invention, a process for preparing a polishing pad is provided, the process comprising preparing a prepolymer composition; preparing a composition for preparing a polishing layer, the composition comprising a prepolymer composition, a foaming agent and a curing agent; and curing the composition for preparing a polishing layer to prepare a polishing layer.

[0166] The step of preparing the prepolymer composition may be a step of reacting a diisocyanate compound with a polyol compound to prepare a polyurethane-based prepolymer. The details of the diisocyanate compound and the polyol compound are described above with respect to the polishing pad.

[0167] The prepolymer composition can have an isocyanate group (NCO group) content of about 5 wt % to about 15 wt %, for example about 5 wt % to about 8 wt %, for example about 5 wt % to about 7 wt %, for example about 8 wt % to about 15 wt %, for example about 8 wt % to about 14 wt %, for example about 8 wt % to about 12 wt %, for example about 8 wt % to about 10 wt %.

[0168] The content of the isocyanate group in the prepolymer composition may be derived from the terminal isocyanate groups of the urethane-based prepolymer, the unreacted isocyanate groups in the diisocyanate compound, and the like.

[0169] At about 80° C., the prepolymer composition may have a viscosity of about 100 cps to about 1000 cps, such as about 200 cps to about 800 cps, such as about 200 cps to about 600 cps, such as about 200 cps to about 550 cps, such as about 300 cps to about 500 cps.

[0170] The blowing agent may include a solid-phase blowing agent or a gas-phase blowing agent.

[0171] If the foaming agent includes a solid-phase foaming agent, the step of preparing a composition for preparing a polishing layer may include mixing a prepolymer composition and a solid-phase foaming agent to prepare a first preliminary composition; and mixing the first preliminary composition and a curing agent to prepare a second preliminary composition.

[0172] The first preliminary composition may have a viscosity of about 1000 cps to about 2000 cps, for example about 1000 cps to about 1800 cps, for example about 1000 cps to about 1600 cps, for example about 1000 cps to about 1500 cps at about 80°C.

[0173] If the foaming agent includes a gas-phase foaming agent, the step of preparing a composition for preparing a polishing layer may include preparing a third preliminary composition including a prepolymer composition and a curing agent; and feeding the gas-phase foaming agent into the third preliminary composition to prepare a fourth preliminary composition.

[0174] In an embodiment, the third preliminary composition may further include a solid-phase foaming agent.

[0175] In an embodiment, the step of preparing the polishing layer includes preparing a mold preheated to a first temperature; injecting a composition for preparing the polishing layer into the preheated mold and curing it; and post-curing the cured composition for preparing the polishing layer under a second temperature condition higher than the preheating temperature.

[0176] In an 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, such as from about 15°C to about 35°C.

[0177] In one embodiment, the first temperature may be about 60°C to about 100°C, such as about 65°C to about 95°C, such as about 70°C to about 90°C.

[0178] In one embodiment, the second temperature may be about 100°C to about 130°C, such as about 100°C to about 125°C, such as about 100°C to about 120°C.

[0179] The step of curing the composition for preparing a polishing layer at the first temperature can be performed for about 5 minutes to about 60 minutes, such as about 5 minutes to about 40 minutes, such as about 5 minutes to about 30 minutes, such as about 5 minutes to about 25 minutes.

[0180] The step of post-curing the composition for preparing a polishing layer cured at the first temperature and the second temperature can be performed for about 5 hours to about 30 hours, such as about 5 hours to about 25 hours, such as about 10 hours to 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.

[0181] The method for preparing a polishing pad may further include processing at least one side of the polishing layer.

[0182] The step of machining at least one side of the polishing layer may include: (1) forming grooves on at least one side of the polishing layer; (2) wire turning at least one side of the polishing layer; and (3) roughening at least one side of the polishing layer.

[0183] In step (1), the grooves may include at least one of concentric circular grooves spaced apart from the center of the polishing layer at a certain interval and radial grooves continuously connected from the center of the polishing layer to the edge of the polishing layer.

[0184] In step (2), wire turning may be performed by cutting a certain thickness of the polishing layer using a cutting tool.

[0185] In step (3), the roughening may be performed by mechanically processing the surface of the polishing layer with a sanding roller.

[0186] The method for preparing the polishing pad may further include laminating a buffer layer on a side of the polishing layer opposite to the polishing surface.

[0187] The polishing layer and the buffer layer may be laminated using a heat seal adhesive.

[0188] A heat seal adhesive is applied to the side of the polishing layer opposite to the polishing surface, a heat seal adhesive is applied to the surface of the buffer layer in contact with the polishing layer, the polishing layer and the buffer layer are laminated so that the sides to which the heat seal adhesive has been applied are in contact, and the two layers can be fused using a pressure roller.

[0189] The buffer layer serves to support the polishing layer and to absorb and disperse impact applied to the polishing layer. Therefore, damage and defects to the object to be polished during a polishing process using the polishing pad can be minimized.

[0190] The cushioning layer may include nonwoven fabric or suede, but is not limited thereto.

[0191] In an embodiment, the buffer layer may be a resin impregnated nonwoven fabric.The nonwoven fabric may be a fiber nonwoven fabric comprising one selected from the group consisting of polyester fiber, polyamide fiber, polypropylene fiber, polyethylene fiber and a combination thereof.

[0192] The resin impregnated in the nonwoven fabric may include polyurethane resin, polybutadiene resin, styrene-butadiene copolymer resin, styrene-butadiene-styrene copolymer resin, acrylonitrile-butadiene copolymer resin, styrene-ethylene-butadiene-styrene copolymer resin, silicone rubber resin, polyester-based elastomer resin, polyamide-based elastomer resin and combinations thereof.

[0193] In another embodiment according to the present invention, a process for preparing a semiconductor device is provided. The method comprises providing a polishing pad including a polishing layer; and contacting a polishing surface of the polishing layer with a surface of an object to be polished. while rotating them relative to each other to polish an object to be polished, wherein the object to be polished comprises an oxide layer, a tungsten layer or a composite layer thereof, and when polishing is performed using a first composition having a hydrogen ion concentration (pH) of 8 to 12, the polishing surface of the polishing layer has a first surface zeta potential (PZ1), which is the value of the surface zeta potential of the polishing surface obtained by the following equation 1 for the first composition; when polishing is performed using a second composition having a hydrogen ion concentration (pH) of 2 to 6, the polishing surface of the polishing layer has a second surface zeta potential (PZ2), which is the value of the surface zeta potential of the polishing surface obtained by the following equation 1 for the second composition; and at least one of the first surface zeta potentials (PZ1) and at least one of the second surface zeta potentials (PZ2) satisfies the following equation 2.

[0194] [Equation 1]

[0195] Surface zeta potential = (-) zeta potential of fixed layer + zeta potential of composition

[0196] [Equation 2]

[0197]

[0198] Figure 4 The process for preparing a semiconductor device according to an embodiment is schematically shown. Figure 4Once the polishing pad (410) according to the embodiment is attached to the platen (420), the semiconductor substrate (430) as the object to be polished is placed on the polishing pad (410). In this case, the surface to be polished of the semiconductor substrate (430) is in direct contact with the polishing surface of the polishing pad (410). The polishing slurry (450) can be sprayed on the polishing pad through the nozzle (440) for polishing. The flow rate of the polishing slurry (450) supplied through the nozzle (440) can be about 10 cm / s depending on the purpose. 3 / min to about 1000cm 3 / min. For example, it can be about 50cm 3 / min to about 500cm 3 / min, but it is not limited thereto.

[0199] Thereafter, the semiconductor substrate (430) and the polishing pad (410) are rotated relative to each other so that the surface of the semiconductor substrate (430) is polished. In this case, the rotation direction of the semiconductor substrate (430) and the rotation direction of the polishing pad (410) may be the same direction or opposite directions. The rotation speeds of the semiconductor substrate (430) and the polishing pad (410) may each be selected in the range of about 10 rpm to about 500 rpm according to the purpose. For example, it may be about 30 rpm to about 200 rpm, but it is not limited thereto.

[0200] The semiconductor substrate (430) mounted on the polishing head (460) is pressed against the polishing surface of the polishing pad (410) with a predetermined load to contact therewith, and then the surface thereof can be polished. The load applied to the polishing surface of the polishing pad (410) through the surface of the semiconductor substrate (430) by the polishing head (460) can be between about 1 gf / cm2 and about 1 gf / cm3 according to the purpose. 2 To about 1000gf / cm 2 For example, it can be about 10 gf / cm 2 To about 800gf / cm 2 , but it is not limited thereto.

[0201] In an embodiment, the semiconductor substrate (430) as the object to be polished may include an oxide layer, a tungsten layer, or a composite layer thereof. Specifically, the semiconductor substrate (430) may include an oxide layer, a tungsten layer, or a composite layer of an oxide layer and a tungsten layer. The composite layer of the oxide layer and the tungsten layer may be a multilayer film in which a tungsten layer is stacked on one side of the oxide layer, or may be a single-layer film in which an oxide region and a tungsten region are mixed in a single layer. Since the object to be polished has such a film substance, and at the same time, the polishing pad has a predetermined electrical characteristic according to Relational Equation 2, a semiconductor device manufactured according to a process for preparing a semiconductor device may have excellent flatness and circuit characteristics.

[0202] In an embodiment, the method for preparing a semiconductor device may further include, in the step of polishing the object to be polished, supplying any one of a slurry for polishing an oxide layer and a slurry for polishing a tungsten layer; or sequentially supplying a slurry for polishing an oxide layer and a slurry for polishing a tungsten layer to a polishing surface.

[0203] For example, if the semiconductor substrate as the object to be polished includes an oxide layer, the process for preparing the semiconductor device may include supplying a slurry for polishing the oxide layer. If the semiconductor substrate includes a tungsten layer, the process for preparing the semiconductor device may include supplying a slurry for polishing the tungsten layer. If the semiconductor substrate includes a composite layer of an oxide layer and a tungsten layer, the process for preparing the semiconductor device may include sequentially supplying a slurry for polishing the oxide layer and a slurry for polishing the tungsten layer to the polishing surface. Here, depending on the process, the slurry for polishing the oxide layer may be supplied first, and then the slurry for polishing the tungsten layer may be supplied later, or the slurry for polishing the tungsten layer may be supplied first, and then the slurry for polishing the oxide layer may be supplied later.

[0204] In an embodiment, the method for preparing a semiconductor device may further include, in the step of polishing the object to be polished, providing a slurry for polishing the oxide layer. For example, the method for preparing a semiconductor device may further include, in the step of polishing the object to be polished, supplying any one of a slurry containing silica particles (silicon dioxide slurry) and a slurry containing cerium dioxide particles (cerium dioxide slurry) as the slurry for polishing the oxide layer; or sequentially supplying a slurry containing silica particles and a slurry containing cerium dioxide particles to the polishing surface.

[0205] For example, a semiconductor substrate as an object to be polished may include an oxide layer, and the process may further include supplying a slurry including silica particles as a slurry for polishing the oxide layer. Alternatively, the process may further include supplying a slurry including cerium oxide particles as a slurry for polishing the oxide layer. Alternatively, the process may also include sequentially supplying a slurry including silica particles and a slurry including cerium oxide particles to the polishing surface. Here, depending on the process, a slurry including silica particles may be supplied first, and then a slurry including cerium oxide particles may be supplied later, or a slurry including cerium oxide particles may be supplied first, and then a slurry including silica particles may be supplied later.

[0206] In one embodiment, in order to maintain the polishing surface of the polishing pad (410) in a state suitable for polishing, the process for preparing a semiconductor device may further include treating the polishing surface of the polishing pad (410) with a dresser (470) while polishing the semiconductor substrate (430).

[0207] In the polishing pad according to the embodiment, the polishing surface of the polishing layer has a predetermined surface zeta potential characteristic, thereby achieving an appropriate range of polishing rates in a polishing environment using both silicon dioxide slurry and ceria slurry to minimize surface defects such as scratches and chatter marks, and applying a single polishing pad continuously or discontinuously to various process steps in the above environment. As a result, high-quality semiconductor devices can be efficiently manufactured using the polishing pad. DETAILED DESCRIPTION

[0209] Hereinafter, the present invention will be described in detail with reference to examples. These examples are set forth to illustrate the present invention, and the scope of the present invention is not limited thereto.

[0210] Example 1

[0211] 1-1: Preparation of polyurethane-based prepolymer

[0212] 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) were added to a four-necked flask, followed by reaction at 80° C. for 3 hours to prepare a polyurethane-based prepolymer having an NCO group content of 9.1% by weight.

[0213] 1-2: Equipment structure

[0214] An apparatus equipped with a polyurethane-based prepolymer tank, a curing agent tank, and an inert gas feed line directly or indirectly connected to a mold was prepared. A pre-prepared polyurethane-based prepolymer and a solid-phase foaming agent (manufacturer: Akzonobel, product name: Expancel 551DE 40d42, average particle size: 40 μm) were added to the polyurethane-based prepolymer tank, and then they were mixed. The amount of the solid-phase foaming agent was 2.2 parts by weight based on 100 parts by weight of the polyurethane-based prepolymer. 4,4"-methylenebis(2-chloroaniline) (MOCA) was added to the curing agent tank.

[0215] 1-3: Preparation of polishing layer

[0216] The polyurethane-based prepolymer, solid-phase foaming agent and curing agent are stirred while they are fed to the mixing head at a specific rate through their respective feed lines. Based on 100 parts by weight of the polyurethane-based prepolymer, the amount of curing agent is 25 parts by weight. The rotation speed of the mixing head is about 5000rpm. Then the mixture composition containing the polyurethane-based prepolymer, solid-phase foaming agent and curing agent mixed in the mixing head is injected into a mold with a width of 1000mm, a length of 1000mm and a height of 3mm. The temperature of the mold is adjusted to about 80 (± 5) ° C. The mixture composition is cured in the mold to prepare a sheet for a polishing layer. Post-curing for about 18 hours is carried out at about 110 (± 5) ° C to prepare a polishing layer.

[0217] 1-4: Preparation of polishing pad

[0218] One side of the polishing layer was wire turned using a cutting tool and grooved using a tip to have an average thickness of 2 mm. A polyester fiber nonwoven fabric was impregnated with a polyurethane resin to prepare a buffer layer. A heat seal adhesive was applied to one side of the buffer layer and the side of the polishing layer opposite to the polishing surface, respectively. The buffer layer and the polishing layer were laminated so that the sides to which the heat seal adhesive had been applied were in contact, and then a pressure roller was used at a temperature of about 140 (± 5) ° C and 2 kgf / cm 2 The polishing pad is prepared by pressing the polishing pad under a pressure of .

[0219] Example 2

[0220] A polishing pad was prepared in the same manner as in Example 1 except that a solid phase foaming agent (manufacturer: Akzonobel, product name: Expancel 461DE 20d70, average particle size: 20 μm) was used as a foaming agent to adjust the number average diameter of pores in the polishing layer as shown in Table 1 below.

[0221] Example 3

[0222] As shown in Table 1 below, a solid phase foaming agent (manufacturer: Akzonobel, product name: Expancel55 1DE 40d42, average particle size: 40 μm) as a foaming agent. When a mixture composition including a polyurethane-based prepolymer, a solid-phase foaming agent and a curing agent is mixed in a mixing head, a gas-phase foaming agent (nitrogen (N2)) is mixed through a separate feed line. The amount of the solid-phase foaming agent is 1.5 parts by weight based on 100 parts by weight of the polyurethane-based prepolymer. At the same time, during the preparation of the mixture composition, a silicone surfactant (manufacturer: Evonik, product name: B8462) is added as a surfactant. A polishing pad is prepared in the same manner as in Example 1, except that the number average diameter of the pores in the polishing layer and the content of inorganic substances are thereby adjusted.

[0223] Example 4

[0224] As shown in Table 1 below, only nitrogen (N2), which is a gas phase foaming agent, was used as a foaming agent without using a solid phase foaming agent, and a surfactant was added during the preparation of a mixture composition including a polyurethane-based prepolymer and a curing agent. A polishing pad was prepared in the same manner as in Example 1, except that the content of the curing agent, the number average diameter of pores in the polishing layer, and the content of the inorganic substance were adjusted, as shown in Table 1 below.

[0225] Example 5

[0226] A polishing pad was prepared in the same manner as in Example 3, except that dimethylthiotoluenediamine (DMTDA) was used as a curing agent, and the number average diameter of pores in the polishing layer and the content of inorganic substances (Si) were adjusted as shown in Table 1 below.

[0227] Comparative Example 1

[0228] A polishing pad was prepared in the same manner as in Example 3, except that the type of solid phase foaming agent (manufacturer: Akzonobel, product name: Expancel 461DET 40d25, average particle size: 40 μm) was changed, and the number average diameter of pores in the polishing layer and the content of inorganic substances were adjusted, as shown in Table 1 below.

[0229] Comparative Example 2

[0230] A polishing pad was prepared in the same manner as in Comparative Example 1, except that dimethylthiotoluenediamine (DMTDA) was used as a curing agent, and the number average diameter of pores in the polishing layer and the content of inorganic substances were adjusted as shown in Table 1 below.

[0231] The specific composition and properties of the polishing layer are summarized in Table 1 below.

[0232] The parts by weight in the following Table 1 are values ​​based on 100 parts by weight of the polyurethane-based prepolymer.

[0233] [Form 1]

[0234]

[0235]

[0236] <Evaluation>

[0237] Test Example 1: Preparation of polishing slurry

[0238] As shown in Table 2 below, a first polishing slurry, a second polishing slurry, and a third polishing slurry were prepared.

[0239] [Form 2]

[0240]

[0241]

[0242] Test Example 2: Measurement of Physical Properties of Polishing Pad

[0243] 2-1: Measurement of the surface zeta potential of the polishing pad

[0244] The surface zeta potential of the polishing pads of Examples and Comparative Examples was measured using a zeta potential measuring apparatus, ZETASIZER Nano-ZS90 (Malvern).

[0245] The zeta potential measurement device is an immersion cell type with electrodes at the ends of the cartridge (with the sample attached between them) and includes an avalanche photodiode detection system.

[0246] Specifically, Figure 3 Schematic diagram showing a surface zeta potential unit. Figure 3 The polishing pad samples (4 mm × 5 mm, 20 mm 2 ) is attached to the sample holder (310). 2 ml of the first polishing slurry, the second polishing slurry or the third polishing slurry diluted to the dilution concentration shown in Table 2 is added to the cuvette (330). The electrophoretic mobility is measured using the Ag / AgCl reversible electrode (320). The measured electrophoretic mobility is converted into a function of the distance from the sample surface. The surface zeta potential of the polishing pad is calculated using the following relationship 1.

[0247] [Equation 1]

[0248] Surface zeta potential = (-) zeta potential of fixed layer + zeta potential of composition

[0249] In equation 1, by measuring Figure 1 The zeta potential of the fixed layer (110) is extrapolated based on the ion diffusion layer (120).

[0250] Figure 2is a graph showing the apparent zeta potential measured for the surface displacement of the polishing pad of Example 1. Specifically, the apparent zeta potential of the surface displacement of the polishing surface of the polishing pad of Example 1 was measured using a first polishing slurry having a zeta potential of -41.3 mV as a tracer. Average values ​​and regression fit curve graphs are plotted. For the first polishing slurry having a zeta potential of -41.3 mV, the first surface zeta potential (PZ1) as the surface zeta potential value derived from Relation 1 was measured to be -60.5 mV. At this time, the zeta potential of the fixed layer was 19.2 mV, the surface equivalent mobility value was -4.744 (μm·cm / Vs), the surface zeta potential uncertainty value was 4.31 (mV), and the surface equivalent mobility uncertainty value was 0.3377 (μm·cm / Vs).

[0251] The surface zeta potential of each polishing pad of the example and the comparative example measured in this manner according to the type of polishing slurry is shown in Table 3 below.

[0252] 2-2: Measurement of polishing rates of tungsten and oxide

[0253] <Polishing Rate of Tungsten (W) Layer>

[0254] A silicon wafer of 300 mm in size with a tungsten (W) layer formed by a CVD process is set in a CMP polisher. The silicon wafer is set on a polishing pad mounted on a platen, with the tungsten layer of the silicon wafer facing downward. Afterwards, the tungsten layer is polished under a polishing load of 2.8 psi while the platen is rotated at a speed of 115 rpm for 30 seconds, and a second polishing slurry (colloidal silica slurry) is supplied to the polishing pad at a rate of 190 ml / min. After polishing is completed, the silicon wafer is separated from the carrier, mounted in a spin dryer, washed with deionized water (DIW), and then air dried for 15 seconds. The film thickness difference of the dry silicon wafer before and after polishing is measured using a contact type sheet resistance meter (with a 4-point probe). The polishing rate is calculated using equation 1 below.

[0255] [Equation 1]

[0256]

[0257] <Polishing rate of oxide layer>

[0258] In addition, in the same device, a silicon wafer with a silicon oxide (SiOx) layer formed by a TEOS plasma CVD process and having a size of 300 mm was used instead of a silicon wafer with a tungsten layer. The silicon wafer was placed on a polishing pad mounted on a platen, with the silicon oxide layer of the silicon wafer facing downward. Thereafter, the silicon oxide layer was polished under a polishing load of 1.4 psi while the platen was rotated at a speed of 115 rpm for 60 seconds, and the first polishing slurry (gas phase silica slurry) or the third polishing slurry (cerium dioxide slurry) was supplied to the polishing pad at a speed of 190 ml / min. After polishing was completed, the silicon wafer was separated from the carrier, mounted in a rotary dryer, washed with deionized water (DIW), and then air dried for 15 seconds. The film thickness difference of the dried silicon wafer before and after polishing was measured using a spectral reflectometer type thickness measuring instrument (manufacturer: Keyence, model: SI-F80R). Then, the polishing rate was calculated using the above equation 1.

[0259] 2-3: Measurement of the number of surface defects such as scratches and chatter marks

[0260] After performing the same CMP process as in Test Example (2-2) using the polishing pads of the example and comparative examples, the surface of the wafer was observed using wafer inspection equipment (ait xp+, KLA Tencor) to measure the number of surface defects such as scratches and chatter marks that appeared on the wafer surface during polishing (threshold: 150, mold filter threshold: 280).

[0261] Scratches are essentially continuous linear scratches. For example, it means Figure 5 Defects in the shape shown.

[0262] Meanwhile, chatter marks mean substantially discontinuous linear scratches. For example, it means Figure 6 Defects in the shape shown.

[0263] The results are shown in Table 3 below.

[0264] [Form 3]

[0265]

[0266]

[0267]

[0268] As can be seen from Table 3, when the desired surface zeta potential in the present invention is satisfied, the polishing rate and the effect of reducing surface defects such as scratches and chatter marks are significantly superior compared to the case where the polishing pads of Comparative Examples 1 and 2 are used.

[0269] Specifically, regarding the polishing rates of the polishing pads of Examples 1 to 5, the polishing rate (OR1) of the polishing pad using the first polishing slurry on the oxide layer is to The polishing rate (WR2) of the tungsten layer by the polishing pad using the second polishing slurry is to And the polishing rate (OR3) of the oxide layer by the polishing pad using the third polishing slurry is to An appropriate polishing rate is achieved with the corresponding type of slurry for the film material to be polished.

[0270] In addition, with respect to surface defects such as scratches and chatter marks of the polishing pads of Examples 1 to 5, the number of surface defects such as scratches and chatter marks on the chip surface was less than 5, whereas when the polishing pads of Comparative Examples 1 and 2 were used, the number of surface defects such as scratches and chatter marks on the chip surface increased significantly by 9 times or more compared to the case of using the polishing pads of the examples.

[0271] As confirmed from the above, in the polishing pad according to the example, the surface zeta potential and the ratio thereof are controlled within a specific range according to the type of polishing slurry, thereby producing an excellent effect of achieving excellent polishing performance for both the oxide film substance and the tungsten film substance and improving surface defects such as scratches and chatter marks appearing on the surface of the semiconductor substrate. That is, the polishing pad achieves appropriate polishing performance for both the oxide film substance and the tungsten film substance with a single polishing pad, thereby producing an advantage that the polishing pad can be applied to various polishing environments continuously and discontinuously for objects to be polished of different materials.

[0272] In addition, in the polishing pad according to the example, excellent polishing performance for oxide layers can be achieved. Specifically, continuous and discontinuous processes can be applied in both batch and fine processing of oxide layers while ensuring excellent polishing performance for both, thereby having advantages from the perspective of multiple processes.

[0273] Furthermore, the polishing pad according to the example achieves excellent polishing performance in a polishing environment using a silica and ceria slurry, thereby producing an advantage of being able to be continuously and discontinuously applied to various polishing environments by using different types of slurries.

[0274] Furthermore, in the polishing pad according to the example, when the slurry environment is acidic and alkaline, or when silica and ceria slurry is used, excellent polishing performance can be achieved with a single pad in the polishing environment.

[0275] [Drawing Reference Numbers]

[0276] 100, 410: polishing pad

[0277] 10: Polishing pad

[0278] 11: Polished surface

[0279] 20: Buffer layer

[0280] 30: Adhesive layer

[0281] 110: Fixed layer

[0282] 120: Ion diffusion layer

[0283] 130: Sliding surface

[0284] 310: Sample rack

[0285] 320: Electrode

[0286] 330: Cuvette

[0287] 420: platen

[0288] 430: Semiconductor substrate

[0289] 440: Nozzle

[0290] 450: Polishing slurry

[0291] 460: Polishing head

[0292] 470: Dresser.

Claims

1. A polishing pad comprising a polishing layer, in, When polishing is performed using a first composition having a hydrogen ion concentration (pH) of 8 to 12, the polishing surface of the polishing layer has a first surface zeta potential (PZ1), the first surface zeta potential being a value of the surface zeta potential of the polishing surface obtained by the following relational formula 1 for the first composition; When polishing is performed using a second composition having a hydrogen ion concentration (pH) of 2 to 6, the polishing surface of the polishing layer has a second surface zeta potential (PZ2), the second surface zeta potential being a value of the surface zeta potential of the polishing surface obtained by the following Relationship 1 for the second composition; and At least one of the first surface zeta potentials (PZ1) and at least one of the second surface zeta potentials (PZ2) satisfy the following relation 2: [Equation 1] Surface zeta potential = (-) zeta potential of fixed layer + zeta potential of composition [Equation 2] 2. The polishing pad according to claim 1, wherein When polishing is performed using a third composition having a hydrogen ion concentration (pH) of 7.5 to 9.5, the polishing surface of the polishing layer has a third surface zeta potential (PZ3), the third surface zeta potential being a value of the surface zeta potential of the polishing surface obtained by the above Relationship 1 for the third composition; and At least one of the first surface zeta potentials (PZ1) and at least one of the third surface zeta potentials (PZ3) satisfy the following relation 3: [Equation 3] 3. The polishing pad according to claim 2, wherein: At least one of the first surface zeta potentials (PZ1), at least one of the second surface zeta potentials (PZ2), and at least one of the third surface zeta potentials (PZ3) satisfy the following relation 4: [Equation 4] 4. The polishing pad according to claim 2, wherein: At least one of the first surface zeta potentials (PZ1), at least one of the second surface zeta potentials (PZ2), and at least one of the third surface zeta potentials (PZ3) satisfy the following relation 5: [Equation 5] 5. The polishing pad according to claim 2, wherein: The zeta potential IZ1 of the fixed layer of the first composition is between +5 mV and about +30 mV, The fixed layer of the second composition has a zeta potential IZ2 of -5 mV to about +15 mV, and The fixed layer of the third composition has a zeta potential IZ3 of -15 mV to about +10 mV.

6. The polishing pad according to claim 2, wherein: The first composition includes silicon dioxide particles having an average particle size of 130 nm to 160 nm and a zeta potential of -50 mV to -30 mV, The second composition comprises silica particles having an average particle size of 30 nm to 50 nm and a zeta potential of +10 mV to +30 mV, and The third composition includes cerium oxide particles having an average particle size of 130 nm to 170 nm, and has a zeta potential of -55 mV to -35 mV.

7. The polishing pad according to claim 1, wherein: The polishing layer includes a cured product including a polyurethane-based prepolymer, a curing agent, and a foaming agent, and the content of inorganic substances in the polishing layer is 5 ppm to 500 ppm.

8. The polishing pad according to claim 7, wherein: The polyurethane-based prepolymer has an isocyanate terminal group content (NCO%) of 5 to 11 wt %, or The foaming agent includes a solid-phase foaming agent, a gas-phase foaming agent or a combination thereof having an average particle size of 5 μm to 200 μm, or Based on 100 parts by weight of the polyurethane-based prepolymer, the curing agent is present in an amount of 18 parts by weight to 27 parts by weight, or The polishing layer has a porous structure including pores having an average diameter of 10 μm to 40 μm.

9. The polishing pad according to claim 2, wherein: When the polishing rate of the polishing surface of the polishing layer using the oxide layer of the first composition is OR1, When the polishing rate of the polishing surface of the polishing layer of the tungsten layer using the second composition is WR2, and When the polishing rate of the polishing surface of the polishing layer of the oxide layer using the third composition is OR3, OR1 is to less than or WR2 is to or OR3 is to 10. A process for preparing a semiconductor device, comprising: providing a polishing pad including a polishing layer; and while a polishing surface of the polishing layer and a surface of an object to be polished are relatively rotated while they are in contact with each other to polish the object to be polished, Wherein, the object to be polished comprises an oxide layer, a tungsten layer or a composite layer thereof, When polishing is performed using a first composition having a hydrogen ion concentration (pH) of 8 to 12, the polishing surface of the polishing layer has a first surface zeta potential (PZ1), the first surface zeta potential being a value of the surface zeta potential of the polishing surface obtained by the following relational formula 1 for the first composition; When polishing is performed using a second composition having a hydrogen ion concentration (pH) of 2 to 6, the polishing surface of the polishing layer has a second surface zeta potential (PZ2), the second surface zeta potential being a value of the surface zeta potential of the polishing surface obtained by the following Relationship 1 for the second composition; and At least one of the first surface zeta potentials (PZ1) and at least one of the second surface zeta potentials (PZ2) satisfy the following relation 2: [Equation 1] Surface zeta potential = (-) zeta potential of fixed layer + zeta potential of composition [Equation 2]

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