Polishing Pad and Method for Manufacturing Semiconductor Element Using the Same

Abstract

To provide a polishing pad, a process for preparing the same, and a process for preparing a semiconductor device using the same.SOLUTION: In the polishing pad, the surface zeta potential and its ratio of a polishing surface are controlled to specific ranges according to the type of polishing slurry, so that it is possible to improve characteristics of scratches and surface defects appearing on a surface of a semiconductor substrate and to further enhance the polishing rate.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a pad applied to a polishing process, and more particularly to a technique for applying such a pad to a method for manufacturing a semiconductor device.

Background Art

[0002] Chemical Mechanical Planarization (CMP) or Chemical Mechanical Polishing (CMP) processes can be performed for various purposes in various technical fields. The CMP process is performed on a predetermined polishing surface of an object to be polished, and can be performed for purposes such as planarization of the polishing surface, removal of aggregated substances, elimination of crystal lattice damage, and removal of scratches and contamination sources.

[0003] The classification of CMP process technologies in semiconductor processes can be divided according to the film quality of the object to be polished or the surface shape after polishing. For example, depending on the film quality of the object to be polished, it can be divided into single silicon or poly silicon, and various oxide films or metal film CMP processes such as tungsten (W), copper (Cu), aluminum (Al), ruthenium (Ru), tantalum (Ta), etc., which are classified according to the type of impurities. Then, according to the surface shape after polishing, it can be classified into a process for relaxing the roughness of the substrate surface, a process for planarizing steps caused by multilayer circuit wiring, and an element isolation process for selectively forming circuit wiring after polishing.

[0004] The CMP process can be applied multiple times in the manufacturing process of semiconductor devices. In the case of semiconductor devices, they include multiple layers, and each layer contains complex and fine circuit patterns. Also, in recent semiconductor devices, while the size of individual chips is decreasing, the patterns of each layer are evolving in the direction of becoming more complex and finer. As a result, in the process of manufacturing semiconductor devices, the purposes of the CMP process have expanded not only for the flattening of circuit wiring but also for applications such as the separation of circuit wiring and the improvement of the wiring surface. Consequently, more sophisticated and reliable CMP performance is required.

[0005] The polishing pad used in such a CMP process can be regarded as one of the most important elements in terms of the thickness uniformity of the object to be polished after polishing, the flatness of the polishing surface, and the polishing quality, etc., as a process component for processing the polishing surface to the level required by friction.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0007] An object of the present invention is to improve the characteristics of surface defects such as scratches and chatter marks that appear on the surface of a semiconductor substrate by controlling the surface zeta potential of the polishing pad and its ratio according to the type of polishing slurry within a specific range, and to be able to continuously and discontinuously apply to each process in various environments with one polishing pad without depending on the type of silica and the type of layer to be polished, and to achieve an appropriate polishing rate for all of these. It is to provide a polishing pad and a method for manufacturing the same.

[0008] Another object of the present invention is to provide a method for manufacturing a semiconductor device that can achieve an appropriate polishing rate using the above-mentioned polishing pad and is useful for both oxide film and tungsten film layers to be polished.

Means for Solving the Problem

[0009] The present invention includes a polishing layer, and when the polishing surface of the polishing layer is polished using a first composition having a hydrogen ion concentration (pH) of 8 or more and 12 or less, it has a first surface zeta potential (PZ1) which is the surface zeta potential value of the polishing surface derived by the following formula 1 with respect to the first composition. When the polishing surface of the polishing layer is polished using a second composition having a hydrogen ion concentration (pH) of 2 or more and 6 or less, it has a second surface zeta potential (PZ2) which is the surface zeta potential value of the polishing surface derived by the following formula 1 with respect to the second composition. Provided is a polishing pad in which at least one of the first surface zeta potentials (PZ1) and at least one of the second surface zeta potentials (PZ2) satisfy the following formula 2. [Formula 1] Surface zeta potential = (-) Zeta potential of the fixed layer + Zeta potential of the composition [Formula 2] -20 ≦ PZ1 / PZ2 ≦ 0

[0010] In another embodiment of the present invention, it includes a step of preparing a prepolymer composition, a step of preparing a composition for manufacturing a polishing layer containing the prepolymer composition, a foaming agent, and a curing agent, and a step of curing the composition for manufacturing the polishing layer to manufacture a polishing layer. When the polishing surface of the polishing layer is polished using a first composition having a hydrogen ion concentration (pH) of 8 or more and 12 or less, it has a first surface zeta potential (PZ1) which is the surface zeta potential value of the polishing surface derived by the formula 1 with respect to the first composition. When the polishing surface of the polishing layer is polished using a second composition having a hydrogen ion concentration (pH) of 2 or more and 6 or less, it has a second surface zeta potential (PZ2) which is the surface zeta potential value of the polishing surface derived by the formula 1 with respect to the second composition. Provided is a method for manufacturing a polishing pad in which at least one of the first surface zeta potentials (PZ1) and at least one of the second surface zeta potentials (PZ2) satisfy the formula 2.

[0011] In still another embodiment of the present invention, there are provided steps of providing a polishing pad including a polishing layer, and polishing a polishing target while relatively rotating the polishing target so that a surface to be polished of the polishing target abuts against a polishing surface of the polishing layer. The polishing target includes an oxide film, a tungsten film, or a composite film thereof. The polishing surface of the polishing layer has a first surface zeta potential (PZ1) which is a surface zeta potential value of the polishing surface derived by Formula 1 with respect to a first composition having a hydrogen ion concentration (pH) of 8 or more and 12 or less. The polishing surface of the polishing layer has a second surface zeta potential (PZ2) which is a surface zeta potential value of the polishing surface derived by Formula 1 with respect to a second composition having a hydrogen ion concentration (pH) of 2 or more and 6 or less. A method for manufacturing a semiconductor device is provided, in which at least one of the first surface zeta potential (PZ1) and at least one of the second surface zeta potential (PZ2) satisfy Formula 2.

Advantages of the Invention

[0012] The polishing pad according to the above embodiment can improve the characteristics of surface defects such as scratches and chatter marks appearing on the surface of a semiconductor substrate by controlling the surface zeta potential of the polishing pad and its ratio according to the type of polishing slurry within a specific range, and can further improve the polishing rate.

[0013] In particular, the polishing pad according to the embodiment of the present invention can realize an appropriate polishing rate in a polishing environment for polishing an oxide film and a tungsten film with one polishing pad by adjusting the surface zeta potential of the polishing pad, and has an advantage that continuous and discontinuous application is possible for each process of the environment with one polishing pad.

[0014] In addition, the polishing pad according to an embodiment of the present invention adjusts the surface zeta potential of the polishing pad, and can achieve an appropriate polishing rate while minimizing surface defects such as scratches and chatter marks in various processes such as the bulk process and the fine process for the oxide film with one polishing pad, and has the advantage that continuous and discontinuous application to each process of the environment is possible with one polishing pad.

[0015] In addition, the polishing pad according to an embodiment of the present invention adjusts the surface zeta potential of the polishing pad, and can achieve appropriate polishing performance within an appropriate range for both silica slurry and ceria slurry with one polishing pad, and has the advantage that continuous and discontinuous application to each process of the environment is possible with one polishing pad.

[0016] Furthermore, the polishing pad according to an embodiment of the present invention adjusts the surface zeta potential of the polishing pad, and can achieve appropriate polishing performance within an appropriate range even when the slurry environment is acidic or basic, or in the case of silica slurry and ceria slurry, with one polishing pad, and has the advantage that continuous and discontinuous application to each process of the environment is possible with one polishing pad.

Brief Description of the Drawings

[0017]

Figure 1

Figure 2

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DETAILED DESCRIPTION OF THE INVENTION

[0018] The advantages and features of the present invention, and the method for achieving them, will become clear by referring to the embodiments described below. However, the present invention is not limited to the embodiments disclosed below, but can be implemented in various different forms. These embodiments are provided only to make the disclosure of the present invention complete and to fully inform those with ordinary knowledge in the technical field to which the present invention belongs of the scope of the invention. The present invention is defined only by the scope of the claims.

[0019] In the drawings, the thickness is enlarged to clearly show a plurality of layers and regions. And in the drawings, for convenience of explanation, the thickness of some layers and regions is exaggerated. Also, the same reference numerals throughout the specification refer to the same components.

[0020] Also, in this specification, when a part such as a layer, film, region, or plate is said to be "on" or "above" another part, this includes not only the case where it is directly above the other part, but also the case where there are other parts in between. Conversely, when a part is said to be "directly above" another part, it means that there are no other parts in between. Further, when a part such as a layer, film, region, or plate is said to be "under" or "below" another part, this includes not only the case where it is directly below the other part, but also the case where there are other parts in between. Conversely, when a part is said to be "directly below" another part, it means that there are no other parts in between.

[0021] In one implementation example according to the present invention, a polishing layer is included, and when the polishing surface of the polishing layer is polished using a first composition in which the hydrogen ion concentration (pH) of the composition is 8 or more and 12 or less, the polishing surface has a first surface zeta potential (PZ1) which is the surface zeta potential value of the polishing surface derived by the following formula 1 with respect to the first composition. When the polishing surface of the polishing layer is polished using a second composition in which the hydrogen ion concentration (pH) of the composition is 2 or more and 6 or less, the polishing surface has a second surface zeta potential (PZ2) which is the surface zeta potential value of the polishing surface derived by the following formula 1 with respect to the second composition. A polishing pad is provided in which at least one of the first surface zeta potential (PZ1) and at least one of the second surface zeta potential (PZ2) satisfy the following formula 2. [Formula 1] Surface zeta potential = (-) Zeta potential of the fixed layer + Zeta potential of the composition [Formula 2] -20 ≦ PZ1 / PZ2 ≦ 0

[0022] The polishing process during the semiconductor manufacturing process is one in which a polishing pad, a polishing slurry, and a film quality to be polished are organically coordinated. Usually, it is performed by supplying a polishing slurry to the contact interface between the polishing pad and the film quality to be polished. The polishing slurry is a composition containing components having electrical characteristics. The film quality to be polished may include a conductor or a semiconductor film quality, and the polishing pad has a predetermined chemical composition. Also, these are physically closely located to each other in the semiconductor manufacturing process. Therefore, due to their respective material characteristics and relative positions during the process, they come to mutually electrically influence each other.

[0023] In the electrical properties of the polishing pad, polishing slurry, and the film quality to be polished, only when the mutual attractive force and repulsive force are realized at an appropriate level can defects on the film quality to be polished, such as scratches and chatter marks, be minimized, and the target polishing performance can be achieved in terms of polishing rate and flatness. For example, if the electrical attractive force among the polishing pad, polishing slurry, and the film quality to be polished is too strong, aggregation of polishing particles in the polishing slurry on the polishing pad will occur, and defects such as scratches or chatter marks may be generated on the surface of the film quality to be polished. For example, if the electrical repulsive force among the polishing pad, polishing slurry, and the film quality to be polished is too strong, the polishing rate of the film quality to be polished will decrease, and problems may occur in terms of process efficiency and polishing flatness. Therefore, adjusting the electrical properties among the polishing pad, polishing slurry, and the film quality to be polished to an appropriate level is a very important factor.

[0024] Zeta Potential generally refers to the physical property that appears from particles contained in a suspension. There are two types of liquid phase layers existing around the particles. An internal region (Stem layer: electron layer) where ions form a strong boundary, and an external region (Defuse) that is relatively weakly bonded. The external region is the region within the theoretical boundary where ions and particles exist stably. For example, when the particles move, the ions in the internal region move within a predetermined boundary. On the other hand, the ions existing outside the predetermined boundary become independent and move like a huge dispersant regardless of the particles. The potential of such a boundary is the zeta potential. The polishing slurry has a self-zeta potential in the state of a suspension in which polishing particles are dispersed.

[0025] Since the polishing pad is a cured resin and not in the state of a suspension, it generally does not have a defined zeta potential. In one implementation example, a surface zeta potential has been devised 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 Equation 1 in relation to a standard composition in the state of a suspension having a predetermined zeta potential.

[0026] Hereinafter, with reference to FIG. 1, the surface zeta potential of the polishing pad will be described in more detail.

[0027] FIG. 1 is a schematic diagram for explaining the surface zeta potential of the polishing pad. Referring to FIG. 1, the polishing pad 100 may include a polishing layer 10. The polishing layer 10 may include a polishing surface 11 for polishing by directly or indirectly contacting the film quality to be polished. The polishing pad 100 may be composed of a single layer of the polishing layer 10 or may be composed of a multilayer structure including the polishing layer 10. Referring to FIG. 1, the polishing pad 100 according to one embodiment may include, but is not limited to, an adhesive layer 30 and a cushion layer 20 on one surface of the polishing layer 10.

[0028] When a predetermined standard composition having a self-zeta potential is supplied onto the polishing surface 11 of the polishing pad 100, it will have a fixed layer 110, an ion diffusion layer 120, and a slipping plane (130). The fixed layer 110 is a layer formed by the particles in the standard composition stably existing on the polishing surface 11, and in the general zeta potential defined from the suspension, it is the region corresponding to the internal region (Stem layer: electron layer). The ion diffusion layer 120 is a region where the particles in the standard composition are relatively weakly bonded to the polishing surface 11 compared to the fixed layer 110 and are separated from the polishing surface 11 by a predetermined distance. The ion diffusion layer 120 is the region corresponding to the external region (Defuse) in the general zeta potential defined from the suspension. The slipping plane 130 exists at the interface between the ion diffusion layer 120 and the fixed layer 110, and the fixed layer 110 and the ion diffusion layer 120 are separated with this as the boundary. The slipping plane 130 is the portion corresponding to a predetermined boundary in the general zeta potential defined from the suspension.

[0029] In one implementation example, the surface zeta potential of the polishing pad according to Formula 1 is defined as the sum of the value obtained by adding a minus (-) sign to the zeta potential value of the fixed layer 110 and the self-zeta potential value of the corresponding standard composition. For example, as shown in FIG. 1, when the charge of the fixed layer 110 has a positive (+) charge, it can be seen that the surface of the polishing surface adjacent to the fixed layer 110 has a negative (-) charge. Therefore, when deriving the surface zeta potential of the polishing pad, a value obtained by adding a (-) sign to the zeta potential value of the fixed layer 110 is applied. The zeta potential of the fixed layer 110 is defined as the value of the Y-intercept of the graph after deriving the change in zeta potential with respect to the distance from the polishing surface for the particles in the standard composition in a graph. The zeta potential of the particles is measured by electrophoretic mobility.

[0030] When the polishing pad satisfies a predetermined condition related to the surface zeta potential according to Formula 1, that is, the condition according to Formula 2, reliable polishing performance can be realized for the interaction between the polishing pad, the polishing slurry used in the process of applying it, and the film quality to be polished.

[0031] The first composition and the second composition are compositions having different hydrogen ion concentrations (pH) of their respective compositions themselves, and the surface zeta potentials of the polishing surfaces for the respective compositions appear as different values. The fact that the ratio of the first surface zeta potential (PZ1) derived from the first composition and the second surface zeta potential (PZ2) derived from the second composition satisfies a predetermined range means that when applying the polishing pad to an actual process, polishing of film qualities of different materials can be performed with excellent performance simultaneously, which has technical significance.

[0032] On the other hand, in another implementation example of the present invention, the polishing pad includes a polishing layer, and when the polishing surface of the polishing layer is polished using a first composition with a hydrogen ion concentration (pH) of the composition being 8 or more and 12 or less, it has a first surface zeta potential (PZ1) which is the surface zeta potential value of the polishing surface derived by the following formula 1 with respect to the first composition. When the polishing surface of the polishing layer is polished using a third composition with a hydrogen ion concentration (pH) of the composition being 7.5 or more and 9.5 or less, it has a third surface zeta potential (PZ3) which is the surface zeta potential value of the polishing surface derived by the following formula 1 with respect to the third composition. At least one of the first surface zeta potential (PZ1) and at least one of the third surface zeta potential (PZ3) may satisfy the following formula 3. [Formula 3] 1 ≦ PZ1 / PZ3 ≦ 5

[0033] The first composition and the third composition are compositions with different hydrogen ion concentrations (pH) of their respective compositions themselves, and the surface zeta potential of the polishing surface with respect to each composition will appear as different values. That the ratio of the first surface zeta potential (PZ1) derived from the first composition and the third surface zeta potential (PZ3) derived from the third composition satisfies a predetermined range means that when applying the polishing pad to an actual process, in various processes such as the bulk process and the fine process for the oxide film to be polished, polishing can be performed with excellent performance while minimizing surface defects such as scratches and chatter marks, and continuous and discontinuous application to each process of the environment is possible with one polishing pad.

[0034] In another embodiment of the present invention, the polishing pad includes a polishing layer. When the polishing surface of the polishing layer is polished using a first composition having a hydrogen ion concentration (pH) of the composition of 8 or more and 12 or less, specifically more than 9.5 and 12 or less, it has a first surface zeta potential (PZ1) which is the surface zeta potential value of the polishing surface derived by the formula 1 with respect to the first composition. When the polishing surface of the polishing layer is polished using a second composition having a hydrogen ion concentration (pH) of the composition of 2 or more and 6 or less, it has a second surface zeta potential (PZ2) which is the surface zeta potential value of the polishing surface derived by the formula 1 with respect to the second composition. When the polishing surface of the polishing layer is polished using a third composition having a hydrogen ion concentration (pH) of the composition of 7.5 or more and 9.5 or less, it has a third surface zeta potential (PZ3) which is the surface zeta potential value of the polishing surface derived by the formula 1 with respect to the third composition. At least one of the first surface zeta potential (PZ1), at least one of the second surface zeta potential (PZ2), and at least one of the third surface zeta potential (PZ3) may satisfy the following formula 4. [Formula 4] 1.1 ≦ PZ1 × PZ2 / PZ3 ≦ 50

[0035] The first composition, the second composition, and the third composition are compositions having different hydrogen ion concentrations (pH) of their respective compositions, and the surface zeta potentials of the polishing surface with respect to each composition will appear as different values. The fact that 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, formula 4) of the third surface zeta potential (PZ3) derived from the third composition satisfy a 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.

[0036] Specifically, the polishing pad that satisfies the formula 4 can be realized in a range with excellent polishing performance in a polishing environment using different types of polishing slurries, more specifically, silica slurry and ceria slurry, and can minimize surface defects such as scratches and chatter marks, and has the advantage that it can be applied continuously or discontinuously to the processes of silica slurry and ceria slurry respectively with one polishing pad.

[0037] In another embodiment of the present invention, the polishing pad includes a polishing layer. When the polishing surface of the polishing layer is polished using a first composition with a hydrogen ion concentration (pH) of the composition being 8 or more and 12 or less, specifically more than 9.5 and 12 or less, it has a first surface zeta potential (PZ1) which is the surface zeta potential value of the polishing surface derived by the formula 1 with respect to the first composition. When the polishing surface of the polishing layer is polished using a second composition with a hydrogen ion concentration (pH) of the composition being 2 or more and 6 or less, it has a second surface zeta potential (PZ2) which is the surface zeta potential value of the polishing surface derived by the formula 1 with respect to the second composition. When the polishing surface of the polishing layer is polished using a third composition with a hydrogen ion concentration (pH) of the composition being 7.5 or more and 9.5 or less, it has a third surface zeta potential (PZ3) which is the surface zeta potential value of the polishing surface derived by the formula 1 with respect to the third composition. At least one of the first surface zeta potential (PZ1), at least one of the second surface zeta potential (PZ2), and at least one of the third surface zeta potential (PZ3) may satisfy the following formula 5. [Formula 5] 1 ≦ (PZ2 - PZ1) / (PZ2 - PZ3) ≦ 5

[0038] The difference (PZ2 - PZ1) between the second surface zeta potential (PZ2) derived from the second composition and the first surface zeta potential (PZ1) derived from the first composition, and the ratio ((PZ2 - PZ1) / (PZ2 - PZ3)) of the difference (PZ2 - PZ3) between the second surface zeta potential (PZ2) derived from the second composition and the third surface zeta potential (PZ3) derived from the third composition satisfying a predetermined range means that when applying the polishing pad to an actual process, polishing with different polishing slurry environments or different types of polishing slurries can be performed simultaneously with excellent performance.

[0039] Specifically, a polishing pad having a polishing surface that satisfies the conditions of Formula 5 can achieve excellent polishing performance even in different polishing environments, more specifically, when the slurry environment is acidic and basic, or when it is silica slurry and ceria slurry, and can minimize surface defects such as scratches and chatter marks, and has the advantage that continuous and discontinuous application to each process of the environment is possible with one polishing pad.

[0040] When the polishing pad satisfies a predetermined condition regarding the surface zeta potential according to Formula 1, that is, a condition according to one or more of Formulas 2 to 5, reliable polishing performance can be achieved for the interaction between the polishing pad, the polishing slurry used in the process to which it is applied, and the film quality to be polished.

[0041] In one implementation example, the hydrogen ion concentration (pH) of the first composition is 8 to 12, for example, 9 to 12, for example, greater than 9.5 and less than or equal to 12, for example, 9 to 11, for example, 10 to 12, for example, 10 to 11.5, for example, 10.5 (±0.5).

[0042] In one implementation example, the pH of the second composition is 2 to 6, for example, 2 to 5, for example, 3 to 6, for example, 3 to 5, for example, 4 (±0.5).

[0043] In one implementation example, the hydrogen ion concentration (pH) of the third composition is 7.5 or more and 9.5 or less, for example, 7.8 to 9.3, for example, 7.8 to 9, for example, 8.5 (±0.5).

[0044] The first composition and the third composition may be basic slurries, and the second composition may be an acidic slurry. The first composition and the third composition are basic slurries, but the first composition contains silica particles and the third composition contains ceria particles, and their pH values may differ from each other by, 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.

[0045] In the polishing pad according to one implementation example, the zeta potential of the fixed layer of Formula 1 may vary depending on the chemical and physical properties of the polishing layer of the polishing pad and the type of the standard composition. Let the zeta potential of the first fixed layer measured with respect to the polishing surface of the polishing pad using the first composition be IZ1, the zeta potential of the second fixed layer measured with respect to the polishing surface of the polishing pad using the second composition be IZ2, and the zeta potential of the third fixed layer measured with respect to the polishing surface of the polishing pad using the third composition be IZ3. Then, IZ1, which is the zeta potential value of the fixed layer with respect to the first composition, is about +5 mV to about +30 mV, IZ2, which is the zeta potential value of the fixed layer with respect to the second composition, is about -5 mV to about +15 mV, and IZ3, which is the zeta potential value of the fixed layer with respect to the third composition, may be -15 mV to +10 mV.

[0046] Specifically, the zeta potential (IZ1) of the first fixed layer may be about +5 mV to about +30 mV, for example, about +8 mV to about +28 mV, for example, about +10 mV to about +25 mV, for example, about +11 mV to about +23 mV, for example, about +15 mV to about +25 mV.

[0047] The zeta potential (IZ2) of the second fixed layer may be about -5 mV to about +15 mV, for example, about -2 mV to about +12 mV, for example, about -1 mV to about 8 mV, for example, about -0.7 mV to about +6 mV, for example, about -0.7 mV to about +4 mV.

[0048] The zeta potential (IZ3) of the third fixing layer can be from about -15 mV to about +10 mV, for example, from about -10 mV to about +8 mV, for example, from about -10 mV to about +7 mV, for example, from about -9 mV to about +6 mV, for example, from about -8.8 mV to about +6 mV.

[0049] In one implementation example, the first composition contains silica particles with an average particle size of about 130 nm to about 160 nm and a zeta potential of -50 mV to -30 mV, the second composition contains silica particles with an average particle size of about 30 nm to about 50 nm and a zeta potential of +10 mV to +30 mV, and the third composition may contain ceria particles with an average particle size of about 130 nm to about 170 nm, specifically about 130 nm to about 160 nm, and a zeta potential of -55 mV to -35 mV.

[0050] The zeta potential of each of the first composition, the second composition, and the third composition can be determined by its components and respective contents. Any three compositions containing the same components in the same contents have the same zeta potential value, but if any three compositions have the same zeta potential value, they do not necessarily contain the same components in the same contents.

[0051] In one implementation example, the first composition contains fumed silica particles, the second composition contains colloidal silica particles, and the third composition may contain ceria particles, such as wet ceria particles.

[0052] A polishing pad having a polishing surface that satisfies at least one of the conditions of the above formulas 2 to 5 while each has the zeta potential value of the aforementioned composition, and at the same time contains fumed silica particles, a second composition containing colloidal silica particles, and a third composition containing ceria particles can be realized in a range with excellent polishing performance in a polishing environment using different types of polishing slurries, can minimize surface defects such as scratches and chatter marks, can be applied continuously or discontinuously to each process of the aforementioned environment with one polishing pad, and has the advantage of ensuring excellent polishing performance for any film quality.

[0053] In one implementation example, the fumed silica particles have an average particle size of 130 nm to 160 nm, for example, 140 nm to 160 nm, and for example, can be 150 (±5) nm. In one implementation example, the colloidal silica particles have an average particle size of 30 nm to 50 nm, for example, 30 nm to 45 nm, and for example, can be 40 (±5) nm. In one implementation example, the ceria particles have an average particle size of 130 nm to 170 nm, for example, 130 nm to 160 nm, for example, 140 nm to 160 nm, and for example, can be 150 (±5) nm.

[0054] According to an implementation example of the present invention, the first composition can be a composition having a zeta potential of the composition itself of -50 mV to -30 mV. The zeta potential of the first composition can be, for example, -50 mV to -35 mV, for example, -50 mV to -40 mV, for example, -48 mV to -35 mV, for example, -48 mV to -40 mV, for example, -47 mV to -35 mV, for example, -47 mV to -40 mV, for example, -46 mV to -38 mV, for example, -46 mV to -40 mV, for example, -45 mV to -38 mV, for example, -45 mV to -40 mV, for example, -44 mV to -38 mV, for example, -44 mV to -40 mV, for example, -43 mV to -38 mV, for example, -43 mV to -40 mV, for example, -42 mV to -38 mV, for example, -42 mV to -40 mV, for example, -42 mV to -41 mV.

[0055] The zeta potential of the second composition can be a composition in which the zeta potential of the composition itself is +10 mV to +30 mV. The zeta potential of the second composition can 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.

[0056] The zeta potential of the third composition can be a composition in which the zeta potential of the composition itself is -55 mV to -35 mV. The zeta potential of the third composition can 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.

[0057] A polishing pad having a polishing surface whose surface zeta potential with respect to a first composition containing fumed silica particles having the above-mentioned average particle size while each having the above-mentioned composition zeta potential value and a second composition containing colloidal silica particles having the above-mentioned average particle size satisfies the conditions of Formula 2 has the advantage of ensuring excellent polishing performance for any film quality when the polishing processes for polishing targets having film qualities of different materials, more specifically, a polishing target having an oxide film and a polishing target having a tungsten (W) film, are performed continuously or discontinuously.

[0058] In addition, a polishing pad having a polishing surface whose surface zeta potential with respect to a first composition containing fumed silica particles having the above-mentioned average particle size while each having the above-mentioned composition zeta potential value and a third composition containing ceria particles having the above-mentioned average particle size satisfies the conditions of Formula 3 has the advantage of ensuring excellent polishing performance for both the bulk process and the fine polishing process for a polishing target having an oxide film when the bulk process and the fine polishing process for the polishing target having an oxide film are performed continuously or discontinuously.

[0059] Also, a polishing pad having a polishing surface with a surface zeta potential satisfying the conditions of the above formula 4 for a first composition containing fumed silica particles each having the above-described zeta potential value of the composition and simultaneously having the above-described average particle diameter, a second composition containing colloidal silica particles having the above-described average particle diameter, and a third composition containing ceria particles having the above-described average particle diameter has the advantage of ensuring excellent polishing performance without surface defects when each polishing step using a silica slurry and a ceria slurry is performed continuously or discontinuously for an oxide film, a tungsten film, or both of them.

[0060] Also, a polishing pad having a polishing surface with a surface zeta potential satisfying the conditions of the above formula 5 for a first composition containing fumed silica particles while each having the zeta potential value of the above-described composition, a second composition containing colloidal silica particles, and a third composition containing ceria particles can achieve excellent polishing performance even in mutually different polishing environments, more specifically, when the slurry environment is acidic and basic, or when it is a silica slurry and a ceria slurry, and can minimize surface defects such as scratches and chatter marks, and has the advantage of being applicable continuously and discontinuously to each process of the above environments with one polishing pad.

[0061] The zeta potentials of the first composition, the second composition, and the third composition each have any one fixed value within the above-described numerical range for each. Thereby, 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 one fixed value.

[0062] The PZ1 can 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.

[0063] The PZ2 can 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.

[0064] The PZ3 can be, for example, -60 mV to -30 mV, such as -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.

[0065] For a polishing pad according to one implementation example, as long as at least one PZ1 value and at least one PZ2 value satisfy the conditions of Formula 2, even if another PZ1 value and another PZ2 value do not satisfy the conditions of Formula 2, the advantages intended in the present invention can be realized. That is, the condition of Formula 2 is that the ratio (PZ1 / PZ2) of at least one value among the first surface zeta potentials (PZ1) of the polishing surface and at least one value among the second surface zeta potentials (PZ2) falls within the range of -20 to 0, and the PZ1 / PZ2 can be, for example, -10 to 0, such as -5 to 0, for example, -4 to 0, for example, -3 to 0.

[0066] For a polishing pad according to another implementation example, as long as at least one PZ1 value and at least one PZ3 value satisfy the conditions of Formula 3, even if another PZ1 value and another PZ3 value do not satisfy the conditions of Formula 3, the advantages intended in the present invention can be realized. That is, the condition of Formula 3 is that the ratio (PZ1 / PZ3) of at least one value among the first surface zeta potentials (PZ1) of the polishing surface and at least one value among the third surface zeta potentials (PZ3) falls within the range of 1 to 5, and the PZ1 / PZ3 can be, for example, greater than 1 and less than or equal to 5, such as greater than 1 and less than or equal to 3, for example, greater than 1 and less than or equal to 2, for example, 1.05 to 1.8, for example, 1.05 to 1.5.

[0067] According to another embodiment, for the polishing pad, 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 conditions of Formula 4, even if any one of another PZ1 value, another PZ2 value, and another PZ3 value does not satisfy the conditions of Formula 4, the advantages targeted in the present invention can be realized. That is, the condition of Formula 4 means that the product (PZ1×PZ2) of at least one value of the first surface zeta potential (PZ1) and at least one value of the second surface zeta potential (PZ2) of the polishing surface, and the ratio (PZ1×PZ2 / PZ3) of at least one value of the third surface zeta potential (PZ3) fall within the range of 1.1 to 50. The PZ1×PZ2 / PZ3 can be, for example, 5 to 50, for example, 10 to 50, for example, 15 to 40, for example, 17 to 35.

[0068] In the PZ1×PZ2 / PZ3, PZ1 and PZ2 correspond 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 corresponds to a surface zeta potential value derived from a composition containing ceria particles. Therefore, the PZ1×PZ2 / PZ3 can mean the ratio of the surface zeta potential value derived from the composition containing silica particles to the surface zeta potential value derived from the composition containing ceria particles. The polishing pad having a polishing surface that satisfies Formula 4 can be realized in a range excellent in polishing performance in a polishing environment using different types of polishing slurries, more specifically, silica slurry and ceria slurry. Surface defects such as scratches and chatter marks can be minimized, and it has the advantage that it can be applied continuously or discontinuously to the processes of silica slurry and ceria slurry respectively with one polishing pad.

[0069] According to another embodiment, for the polishing pad, 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 Formula 5, even if any one of another PZ1 value, another PZ2 value, and another PZ3 value does not satisfy the condition of Formula 5, the advantages targeted in the present invention can be realized. That is, the condition of Formula 5 means that the ratio ((PZ2 - PZ1) / (PZ2 - PZ3)) of the difference (PZ2 - PZ1) between at least one value of the second surface zeta potential (PZ2) and at least one value of the first surface zeta potential (PZ1) of the polishing surface, and the difference (PZ2 - PZ3) between at least one value of the second surface zeta potential (PZ2) and at least one value of the third surface zeta potential (PZ3) of the polishing surface falls within the range of 1 to 5. The (PZ2 - PZ1) / (PZ2 - PZ3) can be, for example, greater than 1 and less than or equal to 5, for example, 1.02 to 4, for example, 1.02 to 3, for example, 1.02 to 2.

[0070] On the other hand, the difference (PZ2 - PZ1) between at least one value of the second surface zeta potential (PZ2) and at least one value of the first surface zeta potential (PZ1) of the polishing surface can be 50 mV to 100 mV. The PZ2 - PZ1 can be, for example, 60 mV to 100 mV, for example, 65 mV to 100 mV, for example, 65 mV to 95 mV, or for example, 65 mV to 90 mV.

[0071] The difference (PZ2 - PZ3) between at least one value of the second surface zeta potential (PZ2) and at least one value of the third surface zeta potential (PZ3) of the polishing surface can be 40 mV to 80 mV. The PZ2 - PZ3 can 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.

[0072] By satisfying the above PZ2 - PZ1 and PZ2 - PZ3 within the above range, when applying the polishing pad to an actual process, polishing in environments of different compositions (polishing slurries) or polishing using different types of compositions can be achieved simultaneously with excellent performance, and the characteristics of surface defects such as scratches and chatter marks that appear on the oxide film or tungsten film can be improved.

[0073] In one implementation example, for the polishing pad with respect to its polishing surface, the polishing rate (OR1) when polishing the oxide film using the first composition may be 2750 Å / min or more and less than 2955 Å / min. The OR1 may be, for example, 2780 Å / min or more and less than 2955 Å / min, for example, 2800 Å / min or more and less than 2955 Å / min, for example, 2850 Å / min to 2952 Å / min, for example, 2890 Å / min to 2950 Å / min, for example, more than 2900 Å / min and 2950 Å / min or less, for example, 2920 Å / min to 2950 Å / min.

[0074] For the polishing pad with respect to its polishing surface, the polishing rate (WR2) when polishing the tungsten (W) film using the second composition may be 730 Å / min or more and 850 Å / min or less. The WR2 may be, for example, 730 Å / min to 830 Å / min, for example, 770 Å / min to 820 Å / min, for example, 780 Å / min to 800 Å / min, for example, 783 Å / min to 800 Å / min.

[0075] For the polishing pad with respect to its polishing surface, the polishing rate (OR3) when polishing the oxide film using the third composition may be 2200 Å / min or more and 2955 Å / min or less. The OR3 may be, for example, 2200 Å / min to 2800 Å / min, for example, 2200 Å / min to 2700 Å / min, for example, 2200 Å / min to 2600 Å / min, for example, 2300 Å / min to 2600 Å / min.

[0076] In one implementation example, the ratio of the OR1 to the WR2 (OR1 / WR2) for the polishing pad can be 3.0 to 4.5, for example, 3.2 to 4.2, for example, 3.5 to 4.0, for example, 3.6 to 3.8, for example, 3.65 to 3.78.

[0077] The OR1 and WR2 can be indirect indicators for determining whether the factors for the polishing rate are realized at the target level among the polishing performances of the oxide film and the tungsten (W) film of the polishing pad. The polishing performance can be evaluated by comprehensively considering various performances such as not only the polishing rate but also the polishing selectivity and the degree of generation of structural defects. The polishing pad according to one implementation example has a polishing surface that satisfies the matters related to the OR1 and WR2, thereby realizing an appropriate polishing rate and at the same time realizing the advantage of minimizing structural defects such as dishing, scratch, and chatter mark.

[0078] In another implementation example, the ratio of the OR1 to the OR3 (OR1 / OR3) for the polishing pad can be 1.0 to 1.5, for example, 1.1 to 1.4, for example, 1.12 to 1.30, for example, 1.12 to 1.17, for example, 1.24 to 1.30.

[0079] The OR1 and OR3 can be indirect indicators for determining whether the factors for the polishing rate are realized at the target level in various processes of the bulk process and the fine process for the oxide film of the polishing pad using silica polishing slurry and / or ceria polishing slurry. The polishing performance can be evaluated by comprehensively considering various performances such as not only the polishing rate but also the polishing selectivity and the degree of generation of structural defects. The polishing pad according to one implementation example has a polishing surface that satisfies the matters related to the OR1 and OR3, can realize an appropriate polishing rate, and at the same time realizes the advantage of minimizing structural defects such as dishing, scratch, and chatter mark.

[0080] In another implementation example, the ratio of the product of OR1 and WR2 to OR3 (OR1×WR2 / OR3) for OR3 can be 800 to 1300, for example, 850 to 1250, for example, 890 to 1200, for example, 890 to 1020, or, for example, 930 to 1020.

[0081] OR1, WR2, and OR3 can be indirect indicators for determining whether the elements for the polishing rate are realized at the target level among the polishing performances of the oxide film and tungsten film of the polishing pad. The polishing performance can be evaluated by comprehensively considering various performances such as not only the polishing rate but also the polishing selectivity and the degree of generation of structural defects. The polishing pad according to one implementation example can realize an appropriate polishing rate and at the same time minimize structural defects such as dishing, scratches, and chatter marks by having a polishing surface that satisfies the matters related to OR1, WR2, and OR3.

[0082] In another implementation example, further, the ratio of the difference between WR2 and OR1 (WR2 - OR1) to the difference between WR2 and OR3 (WR2 - OR3) (WR2 - OR1 / WR2 - OR3) can be 1 to 2, for example, 1 to 1.8, for example, 1 to 1.6, for example, 1 to 1.5, or, for example, 1.1 to 1.5.

[0083] OR1, WR2, and OR3 can be indirect indicators for determining whether the elements for the polishing rate are realized at the target level among the polishing performances of the oxide film and tungsten film of the polishing pad. The polishing performance can be evaluated by comprehensively considering various performances such as not only the polishing rate but also the polishing selectivity and the degree of generation of structural defects. The polishing pad according to one implementation example can realize an appropriate polishing rate and at the same time minimize structural defects such as dishing, scratches, and chatter marks by having a polishing surface that satisfies the matters related to OR1, WR2, and OR3.

[0084] In one implementation example, 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 from about 10 μm to about 40 μm, for example, from about 10 μm to about 35 μm, for example, from about 12 μm to about 30 μm, for example, from about 14 μm to about 30 μm, for example, from about 16 μm to about 30 μm, for example, from about 14 μm to about 28 μm, for example, from about 16 μm to about 28 μm. The number average diameter of the pores may be defined as the average value obtained by dividing the sum of the plurality of pore diameters by the number of the plurality of pores.

[0085] In one implementation example, the polishing layer may include a polishing layer including a cured product formed from a composition including a urethane prepolymer, a curing agent, and a foaming agent. Each component included in the composition will be specifically described below.

[0086] "Prepolymer" means a polymer having a relatively low molecular weight in which the degree of polymerization is terminated at an intermediate stage so as to be easily molded in the production of a cured product. The prepolymer can be molded as a final cured product by itself or after reacting with other polymerizable compounds.

[0087] In one implementation example, the urethane prepolymer can be prepared by reacting an isocyanate compound and a polyol.

[0088] As the isocyanate compound used for preparing the urethane prepolymer, one selected from the group consisting of aromatic diisocyanates, aliphatic diisocyanates, alicyclic diisocyanates, and combinations thereof can be used.

[0089] The isocyanate compound may include, for example, 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, tolidine diisocyanate, 4,4'-diphenyl methane diisocyanate, hexamethylene diisocyanate, dicyclohexylmethane diisocyanate, isophorone diisocyanate, and combinations thereof.

[0090] The polyol may include, for example, one selected from the group consisting of polyether polyol, polyester polyol, polycarbonate polyol, acrylic polyol, and combinations thereof, as a compound containing at least two or more hydroxy groups (-OH) per molecule.

[0091] The polyol may include, for example, one selected from the group consisting of polytetramethylene ether glycol, polypropylene ether glycol, ethylene glycol, 1,2 - propylene glycol, 1,3 - propylene glycol, 1,2 - butanediol, 1,3 - butanediol, 2 - methyl - 1,3 - propanediol, 1,4 - butanediol, neopentyl glycol, 1,5 - pentanediol, 3 - methyl - 1,5 - pentanediol, 1,6 - hexanediol, diethylene glycol, dipropylene glycol, tripropylene glycol, and combinations thereof.

[0092] The polyol may have a weight - average molecular weight (Mw) of about 100 g / mol to about 3000 g / mol. The polyol may have a weight - average molecular weight (Mw) of, for example, about 100 g / mol to about 3000 g / mol, for example, about 100 g / mol to about 2000 g / mol, for example, about 100 g / mol to about 1800 g / mol.

[0093] In one embodiment, the polyol may include a low - molecular - weight polyol having a weight - average molecular weight (Mw) of about 100 g / mol or more and less than about 300 g / mol, and a high - molecular - weight polyol having a weight - average molecular weight (Mw) of about 300 g / mol or more and about 1800 g / mol or less.

[0094] The urethane prepolymer may have a weight - average molecular weight (Mw) of about 500 g / mol to about 3000 g / mol. The urethane prepolymer may have a weight - average molecular weight (Mw) of, for example, about 1000 g / mol to about 2000 g / mol, for example, about 1000 g / mol to about 1500 g / mol.

[0095] In one implementation example, the isocyanate compound for preparing the urethane prepolymer includes 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 urethane prepolymer may include polytetramethylene ether glycol (PTMEG) and diethylene glycol (DEG).

[0096] In other implementation examples, the isocyanate compound for preparing the urethane prepolymer includes an aromatic diisocyanate compound and an alicyclic diisocyanate compound. For example, the aromatic diisocyanate compound includes 2,4-toluene diisocyanate (2,4-TDI) and 2,6-toluene diisocyanate (2,6-TDI), and the alicyclic diisocyanate compound may include dicyclohexylmethane diisocyanate (H12MDI). The polyol compound for preparing the urethane prepolymer may include polytetramethylene ether glycol (PTMEG) and diethylene glycol (DEG).

[0097] The urethane prepolymer may have an isocyanate terminal group content (NCO%) of about 5 wt% to about 11 wt%, for example, about 5 wt% to about 10 wt%, for example, about 5 wt% to about 8 wt%, for example, about 8 wt% to about 10 wt%.

[0098] The isocyanate terminal group content (NCO%) of the urethane prepolymer can be designed by comprehensively adjusting the types and contents of the isocyanate compound and the polyol compound for preparing the urethane prepolymer, process conditions such as temperature, pressure, and time in the process of preparing the urethane prepolymer, and the types and contents of additives used in the preparation of the urethane prepolymer.

[0099] When the content (NCO%) of the isocyanate terminal groups of the urethane prepolymer satisfies the above-mentioned range, the reaction rate, reaction time, and final cured structure when the urethane prepolymer and the curing agent react subsequently can be adjusted in a direction advantageous to the polishing performance according to the use and purpose of the final polishing pad.

[0100] In one implementation example, the content (NCO%) of the isocyanate terminal groups of the urethane prepolymer can be about 8 wt% to about 10 wt%, for example, about 8 wt% to about 9.4 wt%. When the NCO% is less than the above range, as the electrical properties based on the chemical cured structure in the polishing pad, the first surface zeta potential, the second surface zeta potential, and the third surface zeta potential may not be able to achieve the desired polishing performance in terms of polishing rate and flatness, and there may be a problem that the life of the polishing pad is reduced due to an excessive increase in the cutting rate or the like. On the other hand, when the NCO% exceeds the above range, surface defects such as scratches and chatter marks on the semiconductor substrate may increase.

[0101] The curing agent may include, for example, an amine compound or an alcohol compound as a compound for chemically reacting with the urethane prepolymer to form a final cured structure in the polishing layer. Specifically, the curing agent may include one selected from the group consisting of aromatic amines, aliphatic amines, aromatic alcohols, aliphatic alcohols, and combinations thereof.

[0102] For example, the curing agent may include one selected from the group consisting of 4,4'-methylenebis(2-chloroaniline) (4,4'-methylenebis(2-chloroaniline); MOCA), diethyltoluenediamine (diethyltoluenediamine; DETDA), diaminodiphenylmethane, dimethyl thio-toluene diamine (dimethyl thio-toluene diamine; DMTDA), propanediol bis p-aminobenzoate, Methylene bis-methylanthranilate, diaminodiphenylsulfone, m-xylylenediamine, isophoronediamine, ethylenediamine, diethylenetriamine, triethylenetetramine, polypropylenediamine, polypropylenetriamine, bis(4-amino-3-chlorophenyl)methane, and combinations thereof.

[0103] The curing agent may be about 18 parts by weight to about 27 parts by weight, for example, about 19 parts by weight to about 26 parts by weight, for example, about 20 parts by weight to about 26 parts by weight, based on 100 parts by weight of the urethane prepolymer. When the content of the curing agent satisfies the above range, it may be further advantageous for realizing the ratio of the surface zeta potential of the target polishing pad.

[0104] In one implementation example, the curing agent may include 4,4'-methylenebis(2-chloroaniline) or dimethylthiotoluenediamine, and the curing agent may be included in an amount of about 21 parts by weight to about 26 parts by weight based on 100 parts by weight of the urethane prepolymer. Thereby, the urethane cured structure in the polishing layer can exhibit electrical properties based on the chemical characteristics resulting from the reaction between the urethane prepolymer and the curing agent, and such electrical properties may be advantageous for realizing the polishing performance to be achieved by the polishing pad within a target range.

[0105] The foaming agent 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 combinations thereof as a component for forming a pore structure within the polishing layer. In one implementation example, the foaming agent may include a solid-phase foaming agent, a gas-phase foaming agent, or a combination thereof.

[0106] The average particle size of the solid-phase foaming agent may be 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-phase foaming agent means the average particle size of the thermally expanded particles as described hereinafter in the case where the solid-phase foaming agent is thermally expanded particles, and may mean the average particle size of the particles after being expanded by heat or pressure in the case where the solid-phase foaming agent is unexpanded particles as described hereinafter.

[0107] The solid foaming agent may include expandable particles. The expandable particles are particles having the property of being expandable by heat, pressure, etc., and the size in the final polishing layer can be determined by heat, pressure, etc. applied during the process of manufacturing the polishing layer. The expandable particles may include heat-expanded particles, unexpanded particles, or a combination thereof. The heat-expanded particles are particles that have been pre-expanded by heat, meaning particles with little or no size change due to the heat or pressure applied during the manufacturing process of the polishing layer. The unexpanded particles are particles that have not been pre-expanded, meaning particles that expand due to the heat or pressure applied during the manufacturing process of the polishing layer to determine the final size.

[0108] The expandable particles may include an outer skin of resin material and an expansion-inducing component present inside and encapsulated by the outer skin.

[0109] For example, the outer skin may include a thermoplastic resin, and the thermoplastic resin may be one or more selected from the group consisting of vinylidene chloride copolymers, acrylonitrile copolymers, methacrylonitrile copolymers, and acrylic copolymers.

[0110] The expansion-inducing component may include one selected from the group consisting of hydrocarbon compounds, chlorofluorocompounds, tetraalkylsilane compounds, and combinations thereof.

[0111] Specifically, the hydrocarbon compound may include one selected from the group consisting of ethane, ethylene, propane, propene, n-butane, isobutene, n-butene, isobutene, n-pentane, isopentane, neopentane, n-hexane, heptane, petroleum ether, and combinations thereof.

[0112] The chlorofluorinated compound may include one selected from the group consisting of trichlorofluoromethane (CCl3F), dichlorodifluoromethane (CCl2F2), chlorotrifluoromethane (CClF3), tetrafluoroethylene (CClF2-CClF2), and combinations thereof.

[0113] The tetraalkylsilane compound may include one selected from the group consisting of tetramethylsilane, trimethylethylsilane, trimethylisopropylsilane, trimethyl-n-propylsilane, and combinations thereof.

[0114] The solid-phase foaming agent may contain inorganic component-treated particles as required. For example, the solid-phase foaming agent may contain expandable particles treated with inorganic components. In one implementation example, the solid-phase foaming agent may contain expandable particles treated with silica (SiO2) particles. The treatment of the inorganic components of the solid-phase foaming agent can prevent aggregation between multiple particles. The solid-phase foaming agent treated with inorganic components may have different chemical, electrical, and / or physical properties on the surface of the foaming agent compared to the solid-phase foaming agent not treated with inorganic components.

[0115] The content of the solid-phase foaming agent may be about 0.5 parts by weight to about 10 parts by weight, for example, about 1 part by weight to about 3 parts by weight, for example, about 1.3 parts by weight to about 2.7 parts by weight, for example, about 1.3 parts by weight to about 2.6 parts by weight, based on 100 parts by weight of the urethane prepolymer.

[0116] The type and content of the solid-phase foaming agent can be designed according to the intended pore structure and physical properties of the polishing layer.

[0117] The gas-phase foaming agent may contain an inert gas. The gas-phase foaming agent is introduced during the reaction process of the urethane prepolymer and the curing agent and can be used as a pore-forming element.

[0118] The type of the inert gas is not particularly limited as long as it is a gas that does not participate in the reaction between the urethane prepolymer and the curing agent. For example, the inert gas may contain one selected from the group consisting of nitrogen gas (N2), argon gas (Ar), helium gas (He), and combinations thereof. Specifically, the inert gas may contain nitrogen gas (N2) or argon gas (Ar).

[0119] The type and content of the gas-phase foaming agent can be designed according to the intended pore structure and physical properties of the polishing layer. In one implementation example, the foaming agent may contain a solid-phase foaming agent. For example, the foaming agent may consist only of a solid-phase foaming agent.

[0120] The solid-phase foaming agent contains expandable particles, and the expandable particles may include thermally expanded particles. For example, the solid-phase foaming agent may consist only of thermally expanded particles. If it does not contain the unexpanded particles and consists only of thermally expanded particles, the variability of the pore structure decreases, but the possibility of prior prediction increases, which may be advantageous for realizing uniform pore characteristics over the entire region of the polishing layer.

[0121] In one implementation example, the thermally expanded particles may be particles having an average particle size of about 5 μm to about 200 μm. The average particle size of the thermally expanded particles is about 5 μm to about 100 μm, for example, about 10 μm to about 80 μm, for example, about 20 μm to about 70 μm, for example, about 20 μm to about 50 μm, for example, about 30 μm to about 70 μm, for example, about 25 μm to 45 μm, for example, about 40 μm to about 70 μm, for example, about 40 μm to about 60 μm. The average particle size is defined as D50 of the thermally expanded particles.

[0122] In one implementation example, the density of the thermally expanded particles is about 30 kg / m 3 ~ about 80 kg / m 3 、 for example, about 35 kg / m 3 ~ about 80 kg / m 3 、 for example, about 35 kg / m 3 ~ about 75 kg / m 3 、 for example, about 38 kg / m 3 ~ about 72 kg / m 3 、 for example, about 40 kg / m 3 ~ about 75 kg / m 3 、 for example, about 40 kg / m 3 ~ about 72 kg / m 3 and may be.

[0123] In one implementation example, the solid-phase foaming agent may contain expandable particles that have not been treated with an inorganic component. Specifically, the solid-phase foaming agent may consist of expandable particles that have not been treated with an inorganic component. By using expandable particles that have not been treated with an inorganic component as the solid-phase foaming agent, the chemical and electrical properties of the surface of the solid-phase foaming agent may be advantageous for realizing the desired surface zeta potential characteristics.

[0124] In one implementation example, 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. Matters regarding the solid-phase foaming agent are as described above.

[0125] The gas-phase foaming agent may include nitrogen gas.

[0126] The gas-phase foaming agent may be injected through a predetermined injection line during the process of mixing the urethane prepolymer, the solid-phase foaming agent, and the curing agent. The injection rate of the gas-phase foaming agent may be about 0.8 L / min to about 2.0 L / min, for example, about 0.8 L / min to about 1.8 L / min, for example, about 0.8 L / min to about 1.7 L / min, for example, about 1.0 L / min to about 2.0 L / min, for example, about 1.0 L / min to about 1.8 L / min, for example, about 1.0 L / min to about 1.7 L / min.

[0127] The composition for manufacturing the polishing layer may further include other additives such as a surfactant and a reaction rate regulator. Names such as the "surfactant" and the "reaction rate regulator" are arbitrarily designated names based on the main roles of the substances, and each of the substances does not necessarily perform only the functions according to the roles by those names.

[0128] The surfactant is not particularly limited as long as it serves to prevent phenomena such as aggregation or overlap of pores. For example, the surfactant may include a silicone-based surfactant.

[0129] The surfactant can be used in a content of about 0.2 parts by weight to about 2 parts by weight based on 100 parts by weight of the urethane prepolymer. Specifically, the surfactant can be contained in a content of about 0.2 parts by weight to about 1.9 parts by weight, for example, about 0.2 parts by weight to about 1.8 parts by weight, for example, about 0.2 parts by weight to about 1.7 parts by weight, for example, about 0.2 parts by weight to about 1.6 parts by weight, for example, about 0.2 parts by weight to about 1.5 parts by weight, for example, about 0.5 parts by weight to 1.5 parts by weight based on 100 parts by weight of the urethane prepolymer. When the surfactant is included in the content within the above range, pores derived from the gas-phase foaming agent can be stably formed and maintained in the mold.

[0130] The reaction rate regulator serves to promote or delay the reaction, and a reaction accelerator, a reaction inhibitor, or any of them can be used according to the purpose. The reaction rate regulator may include a reaction accelerator. For example, the reaction accelerator can be one or more reaction accelerators selected from the group consisting of tertiary amine-based compounds and organometallic-based compounds.

[0131] Specifically, the reaction rate regulator may include one or more selected from the group consisting of triethylenediamine, dimethylethanolamine, tetramethylbutanediamine, 2-methyl-triethylenediamine, dimethylcyclohexylamine, triethylamine, triisopropanolamine, 1,4-diazabicyclo(2,2,2)octane, bis(2-methylaminoethyl)ether, trimethylaminoethylethanolamine, N,N,N,N,N''-pentamethyldiethylenetriamine, dimethylaminoethylamine, dimethylaminopropylamine, benzyldimethylamine, N-ethylmorpholine, N,N-dimethylaminoethylmorpholine, N,N-dimethylcyclohexylamine, 2-methyl-2-azanorborane, dibutyltin dilaurate, stannous octoate, dibutyltin diacetate, dioctyltin diacetate, dibutyltin maleate, dibutyltin di-2-ethylhexanoate, and dibutyltin dimercaptide. Specifically, the reaction rate regulator may include one or more selected from the group consisting of benzyldimethylamine, N,N-dimethylcyclohexylamine, and triethylamine.

[0132] The reaction rate regulator may be used in an amount of about 0.05 parts by weight to about 2 parts by weight based on 100 parts by weight of the urethane prepolymer. Specifically, the reaction rate regulator may be used in an amount of about 0.05 parts by weight to about 1.8 parts by weight, for example, about 0.05 parts by weight to about 1.7 parts by weight, for example, about 0.05 parts by weight to about 1.6 parts by weight, for example, about 0.1 parts by weight to about 1.5 parts by weight, for example, about 0.1 parts by weight to about 0.3 parts by weight, for example, about 0.2 parts by weight to about 1.8 parts by weight, for example, about 0.2 parts by weight to about 1.7 parts by weight, for example, about 0.2 parts by weight to about 1.6 parts by weight, for example, about 0.2 parts by weight to about 1.5 parts by weight, for example, about 0.5 parts by weight to about 1 part by weight based on 100 parts by weight of the urethane prepolymer. When the reaction rate regulator is used within the above-mentioned content range, the curing reaction rate of the prepolymer composition can be appropriately adjusted to form a polishing layer having pores and hardness of a desired size.

[0133] In one implementation example, the content of the inorganic substance in the polishing layer can be from about 5 ppm to about 500 ppm.

[0134] The inorganic substance may include one or more elements selected from the group consisting of, for example, silicon (Si) element, phosphorus (P) element, and calcium (Ca) element.

[0135] The inorganic substance can be derived from various sources. For example, the inorganic substance may be derived from various additives used in the manufacturing process of the polishing layer such as a foaming agent. At this time, the additive serving as the source of the inorganic substance may include, for example, one selected from the group consisting of a foaming agent, a surfactant, a reaction rate regulator, and combinations thereof.

[0136] The content of the inorganic substance in the polishing layer may be designed within an appropriate range by using only one of the foaming agent or other additives alone and adjusting its type and content, or by using the foaming agent and other additives simultaneously and adjusting their types and contents.

[0137] The content of the inorganic substance in the polishing layer can be from about 5 ppm to about 500 ppm, for example, from about 5 ppm to about 400 ppm, for example, from about 8 ppm to about 300 ppm, for example, from about 220 ppm to about 400 ppm, for example, from about 5 ppm to about 180 ppm. At this time, the content of the inorganic substance in the polishing layer may be measured by inductively coupled plasma (ICP) analysis.

[0138] The content of the inorganic substance in the polishing layer can significantly affect the surface zeta potential of the polishing pad. When the content of the inorganic substance satisfies the above range, the surface zeta potential of the target polishing pad, specifically, the ratio of the surface zeta potential of the polishing pad depending on the type of polishing slurry, can be realized within a predetermined range. If the content of the inorganic substance exceeds about 500 ppm in the polishing layer, the composition of the polishing layer may change, and the surface zeta potential of the polishing pad may change. Then, in the process of manufacturing a semiconductor element, the electrical correlation between the polishing layer and the polishing slurry may change in a direction that significantly increases surface defects such as scratches and chatter marks on the semiconductor substrate.

[0139] Hereinafter, a method for manufacturing the polishing pad will be described in detail.

[0140] In another embodiment according to the present invention, a method for manufacturing a polishing pad may be provided, which includes a step of preparing a prepolymer composition, a step of preparing a composition for manufacturing a polishing layer including the prepolymer composition, a foaming agent, and a curing agent, and a step of curing the composition for manufacturing the polishing layer to manufacture a polishing layer.

[0141] The step of preparing the prepolymer composition may be a step of reacting a diisocyanate compound and a polyol compound to prepare a urethane prepolymer. Matters regarding the diisocyanate compound and the polyol compound are as described above for the polishing pad.

[0142] The content of the isocyanate group (NCO group) in the prepolymer composition may be 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, 8 wt% to about 10 wt%.

[0143] The isocyanate group content of the prepolymer composition may be derived from the terminal isocyanate groups of the urethane prepolymer, unreacted isocyanate groups that have not reacted among the diisocyanate compounds, and the like.

[0144] The viscosity of the prepolymer composition is about 100 cps to about 1000 cps at about 80°C, for example, about 200 cps to about 800 cps, for example, about 200 cps to about 600 cps, for example, about 200 cps to about 550 cps, for example, about 300 cps to about 500 cps.

[0145] The blowing agent may include a solid-phase blowing agent or a gas-phase blowing agent.

[0146] When the blowing agent includes a solid-phase blowing agent, the step of preparing the composition for manufacturing the abrasive layer may include a step of mixing the prepolymer composition and the solid-phase blowing agent to prepare a first preliminary composition, and a step of mixing the first preliminary composition and a curing agent to prepare a second preliminary composition.

[0147] The viscosity of the first preliminary composition is about 1000 cps to about 2000 cps at about 80°C, 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.

[0148] When the blowing agent includes a gas-phase blowing agent, the step of preparing the composition for manufacturing the abrasive layer may include a step of preparing a third preliminary composition including the prepolymer composition and the curing agent, and a step of injecting the gas-phase blowing agent into the third preliminary composition to prepare a fourth preliminary composition.

[0149] In one implementation example, the third preliminary composition may further include a solid-phase blowing agent.

[0150] In one implementation example, the step of manufacturing the abrasive layer may include a step of preparing a mold preheated at a first temperature, a step of injecting the composition for manufacturing the abrasive layer into the preheated mold and curing it, and a step of post-curing the cured composition for manufacturing the abrasive layer under a second temperature condition higher than the preheating temperature.

[0151] In one implementation example, the temperature difference between the first temperature and the second temperature is from about 10°C to about 40°C, for example, from about 10°C to about 35°C, for example, it may be from about 15°C to about 35°C.

[0152] In one implementation example, the first temperature may be from about 60°C to about 100°C, for example, from about 65°C to about 95°C, for example, from about 70°C to about 90°C.

[0153] In one implementation example, the second temperature is from about 100°C to about 130°C, for example, from about 100°C to 125°C, for example, it may be from about 100°C to about 120°C.

[0154] The step of curing the composition for manufacturing the polishing layer at the first temperature may be performed for about 5 minutes to about 60 minutes, for example, about 5 minutes to about 40 minutes, for example, about 5 minutes to about 30 minutes, for example, about 5 minutes to about 25 minutes.

[0155] The step of post-curing the composition for manufacturing the polishing layer cured at the first temperature at the second temperature may be performed for about 5 hours to about 30 hours, for example, about 5 hours to about 25 hours, for example, about 10 hours to about 30 hours, for example, about 10 hours to about 25 hours, for example, about 12 hours to about 24 hours, for example, about 15 hours to about 24 hours.

[0156] The method for manufacturing the polishing pad may include a step of processing at least one surface of the polishing layer.

[0157] The step of processing at least one surface of the polishing layer may include at least one of the following steps: (1) forming a groove on at least one surface of the polishing layer, (2) performing line turning on at least one surface of the polishing layer, and (3) roughening at least one surface of the polishing layer.

[0158] In the step (1), the groove may include at least one of a concentric groove formed at a predetermined interval from the center of the polishing layer and a radial groove continuously connected from the center of the polishing layer to the edge of the polishing layer.

[0159] In the step (2), the line turning process can be performed by a method of shaving off a predetermined thickness of the polishing layer using a cutting tool.

[0160] In the step (3), the roughening can be performed by a method of processing the surface of the polishing layer with a sanding roller.

[0161] The method for manufacturing the polishing pad may further include a step of laminating a cushion layer on the back surface of the polishing surface of the polishing layer.

[0162] The polishing layer and the cushion layer can be laminated via a heat-sealing adhesive.

[0163] Apply the heat-sealing adhesive on the back surface of the polishing surface of the polishing layer, apply the heat-sealing adhesive on the surface of the cushion layer that contacts the polishing layer, laminate the polishing layer and the cushion layer so that the surfaces coated with the respective heat-sealing adhesives are in contact, and then use a pressure roller to fuse the two layers.

[0164] The cushion layer serves to absorb and disperse external impacts applied to the polishing layer while supporting the polishing layer, thereby minimizing the occurrence of damage and defects to the object to be polished during the polishing process to which the polishing pad is applied.

[0165] The cushion layer may include, but is not limited to, non-woven fabric or suede.

[0166] In one embodiment, the cushion layer may be a resin-impregnated non-woven fabric. The non-woven fabric may be a fibrous non-woven fabric including one selected from the group consisting of polyester fibers, polyamide fibers, polypropylene fibers, polyethylene fibers, and combinations thereof.

[0167] The resin impregnated in the nonwoven fabric may include one selected from the group consisting of a polyurethane resin, a polybutadiene resin, a styrene-butadiene copolymer resin, a styrene-butadiene-styrene copolymer resin, an acrylonitrile-butadiene copolymer resin, a styrene-ethylene-butadiene-styrene copolymer resin, a silicone rubber resin, a polyester-based elastomer resin, a polyamide-based elastomer resin, and combinations thereof.

[0168] In still another embodiment according to the present invention, there is provided a polishing pad including a polishing layer, and a step of polishing a polishing target while relatively rotating the polishing target so that a surface to be polished of the polishing target abuts on a polishing surface of the polishing layer. The polishing target includes an oxide film, a tungsten film, or a composite film thereof. The polishing surface of the polishing layer has a first surface zeta potential (PZ1) which is a surface zeta potential value of the polishing surface derived by the following formula 1 with respect to a first composition having a hydrogen ion concentration (pH) of 8 or more and 12 or less. The polishing surface of the polishing layer has a second surface zeta potential (PZ2) which is a surface zeta potential value of the polishing surface derived by the following formula 1 with respect to a second composition having a hydrogen ion concentration (pH) of 2 or more and 6 or less. A method for manufacturing a semiconductor device is provided, in which at least one of the first surface zeta potential (PZ1) and at least one of the second surface zeta potential (PZ2) satisfy the following formula 2.

[0169] [Formula 1] Surface zeta potential = (-) zeta potential of the fixed layer + zeta potential of the composition [Formula 2] -20 ≦ PZ1 / PZ2 ≦ 0 FIG. 4 shows a schematic process of a manufacturing process of a semiconductor device according to one implementation example. Referring to FIG. 4, after mounting a polishing pad 410 according to the one implementation example on a surface plate 420, a semiconductor substrate 430 to be polished is disposed on the polishing pad 410. At this time, the surface to be polished of the semiconductor substrate 430 is brought into direct contact with the polishing surface of the polishing pad 410. For polishing, polishing slurry 450 may be sprayed onto the polishing pad via a nozzle 440. The flow rate of the polishing slurry 450 supplied via the nozzle 440 is selected according to the purpose within a range of about 10 cm 3 / min to about 1000 cm 3 / min, and for example, may be about 50 cm 3 / min to about 500 cm 3 / min, but is not limited thereto.

[0170] Thereafter, the semiconductor substrate 430 and the polishing pad 410 may rotate relative to each other so that the surface of the semiconductor substrate 430 can be polished. At this time, the rotation direction of the semiconductor substrate 430 and the rotation direction of the polishing pad 410 may be the same direction or the opposite direction. The rotation speeds of the semiconductor substrate 430 and the polishing pad 410 are each selected according to the purpose within a range of about 10 rpm to about 500 rpm, and for example, may be about 30 rpm to about 200 rpm, but are not limited thereto.

[0171] The semiconductor substrate 430 is mounted on a polishing head 460 and then pressed against the polishing surface of the polishing pad 410 with a predetermined load so that its surface can be polished. The load applied by the polishing head 460 to bring the surface of the semiconductor substrate 430 into contact with the polishing surface of the polishing pad 410 is selected according to the purpose within a range of about 1 gf / cm 2 to about 1000 gf / cm 2 and for example, may be about 10 gf / cm 2 to about 800 gf / cm 2 but is not limited thereto.

[0172] In one implementation example, the semiconductor substrate 430 to be polished may include an oxide film, a tungsten film, or a composite film thereof. Specifically, the semiconductor substrate 430 may include an oxide film, a tungsten film, or a composite film of an oxide film and a tungsten film. The composite film of the oxide film and the tungsten film may be a multilayer film in which the tungsten film is laminated on one surface of the oxide film, or may be a single-layer film in which an oxide region and a tungsten region are mixed in one layer. While the object to be polished has such film quality characteristics, and at the same time the polishing pad has the predetermined electrical characteristics according to Formula 2, the semiconductor device manufactured by the method for manufacturing a semiconductor device may have excellent flatness and circuit characteristics.

[0173] In one implementation example, the method for manufacturing a semiconductor device may further include, in the step of polishing the object to be polished, supplying either the slurry for polishing the oxide film or the slurry for polishing the tungsten film, or sequentially supplying the slurry for polishing the oxide film and the slurry for polishing the tungsten film to the polishing surface.

[0174] For example, when the semiconductor substrate as the object to be polished includes an oxide film, the method for manufacturing a semiconductor device may include the step of supplying the slurry for polishing the oxide film. When the semiconductor substrate includes a tungsten film, the method for manufacturing a semiconductor device may include the step of supplying the slurry for polishing the tungsten film. When the semiconductor substrate includes a composite film of an oxide film and a tungsten film, the method for manufacturing a semiconductor device may include the step of sequentially supplying the slurry for polishing the oxide film and the slurry for polishing the tungsten film to the polishing surface. At this time, depending on the process, the slurry for polishing the oxide film may be supplied first and then the slurry for polishing the tungsten film may be supplied later, or the slurry for polishing the tungsten film may be supplied first and then the slurry for polishing the oxide film may be supplied later.

[0175] In one implementation example, the method for manufacturing the semiconductor device may further include a step of supplying the slurry for oxide film polishing in the step of polishing the object to be polished. For example, the method for manufacturing the semiconductor device may include a step of supplying either a slurry containing silica particles (silica slurry) or a slurry containing ceria particles (ceria slurry) as the slurry for oxide film polishing in the step of polishing the object to be polished, or may further include a step of sequentially supplying the slurry containing silica particles and the slurry containing ceria particles to the polishing surface.

[0176] For example, the semiconductor substrate as the object to be polished may include an oxide film, and the method may include a step of supplying a slurry containing silica particles as the slurry for oxide film polishing. Alternatively, the method may include a step of supplying a slurry containing ceria particles as the slurry for oxide film polishing. Alternatively, the method may include a step of sequentially supplying a slurry containing silica particles and a slurry containing ceria particles to the polishing surface as the slurry for oxide film polishing. At this time, depending on the process, the slurry containing silica particles may be supplied first and then the slurry containing ceria particles may be supplied later, or the slurry containing ceria particles may be supplied first and then the slurry containing silica particles may be supplied later.

[0177] In one implementation example, the method for manufacturing the semiconductor device may further include a step of processing the polishing surface of the polishing pad 410 by a conditioner 470 simultaneously with the polishing of the semiconductor substrate 430 in order to maintain the polishing surface of the polishing pad 410 in a state suitable for polishing.

[0178] Due to the polishing surface of the polishing layer of the polishing pad according to the one implementation example having predetermined surface zeta potential characteristics, the polishing rate can be realized within an appropriate range for any polishing environment using silica slurry and ceria slurry. It not only minimizes surface defects such as scratches and chatter marks, but also enables continuous and discontinuous application to each process of the environment with one polishing pad. Thereby, a semiconductor device of excellent quality can be efficiently manufactured using the polishing pad.

[0179] (Example) The present invention will be described more specifically by way of examples below. The following examples are merely illustrative of the present invention, and the scope of the present invention is not limited thereto.

[0180] (Example 1) [1-1: Preparation of urethane prepolymer] 2,4-Toluene diisocyanate (2,4-TDI), 2,6-toluene diisocyanate (2,6-TDI), dicyclohexylmethane diisocyanate (H12MDI), polytetramethylene ether glycol (PTMEG), and diethylene glycol (DEG) were charged into a four-necked flask and reacted at 80 °C for 3 hours to prepare a urethane prepolymer having an NCO group content of 9.1% by weight.

[0181] [1-2: Configuration of the device] An apparatus equipped with a urethane prepolymer tank, a curing agent tank, and an inert gas injection line directly or indirectly connected to a mold (Mold) was prepared. The prepared urethane prepolymer and a solid foaming agent (Expancel® 551 DE 40 d42, AkzoNobel, average particle size: 40 μm) were charged into the urethane prepolymer tank and mixed. The solid foaming agent was used in an amount of 2.2 parts by weight based on 100 parts by weight of the urethane prepolymer. The curing agent tank was filled with 4,4'-methylenebis(2-chloroaniline) (MOCA).

[0182] [1-3: Production of the polishing layer] Through each input line, the urethane prepolymer, the solid foaming agent, and the curing agent were mixed while being input into the mixing head at a predetermined rate. The curing agent was input in an amount of 25 parts by weight with respect to 100 parts by weight of the urethane prepolymer. The rotational speed of the mixing head was set at about 5000 rpm. After the mixed composition containing the urethane prepolymer, the solid foaming agent, and the curing agent was mixed in the mixing head, it was poured into a mold having a length of 1000 mm, a width of 1000 mm, and a height of 3 mm. The temperature of the mold was adjusted to about 80 (±5) °C. The mixed composition solidified in the mold and was manufactured as a sheet for a polishing layer. The polishing layer was manufactured by post-curing the sheet at about 110 (±5) °C for about 18 hours.

[0183] [1-4: Production of polishing pad] One surface of the polishing layer was turned by a cutting tool and grooved using a chip, and it was manufactured to have an average thickness of 2 mm through this process. A cushion layer in which a polyurethane resin was impregnated in a polyester fiber nonwoven fabric was provided, and a thermally fused adhesive was applied to one surface of the cushion layer and the back surface of the groove-forming surface of the polishing layer, respectively. The cushion layer and the polishing layer were laminated so that the surfaces coated with the respective thermally fused adhesives were in contact with each other, and were pressure-laminated under the pressure conditions of a temperature of about 140 (±5) °C and 2 kgf / cm 2 to manufacture a polishing pad.

[0184] (Example 2) As shown in Table 1 below, a solid foaming agent (Expancel 461 DE 20 d70, AkzoNobel, average particle size: 20 μm) was used as the foaming agent, and a polishing pad was manufactured in the same manner as in Example 1, except that the number average diameter of the pores in the polishing layer was adjusted thereby.

[0185] (Example 3) As shown in Table 1 below, a solid foaming agent (Expancel 551 DE 40 d42, AkzoNobel, average particle size: 40 μm) was used as the foaming agent. When the mixed composition containing the urethane prepolymer, the solid foaming agent, and the curing agent was mixed in the mixing head, a gaseous foaming agent (nitrogen gas (N2)) was mixed and used via a separate input line. 1.5 parts by weight of the solid foaming agent was used with respect to 100 parts by weight of the urethane prepolymer. On the other hand, a silicone surfactant (B8462, Evonik) was added during the production of the mixed composition as the surfactant. Thus, a polishing pad was produced in the same manner as in Example 1, except that the number average diameter of pores and the inorganic content in the polishing layer were adjusted.

[0186] (Example 4) As shown in Table 1 below, no solid foaming agent was used as the foaming agent, and only nitrogen gas (N2), which is a gaseous foaming agent, was used. A surfactant was added when preparing the mixed composition containing the urethane prepolymer and the curing agent. A polishing pad was produced in the same manner as in Example 1, except that the content of the surfactant, the number average diameter of pores in the polishing layer, and the content of inorganic substances were adjusted as shown in Table 1 below.

[0187] (Example 5) As shown in Table 1 below, dimethyl thio-toluene diamine (DMTDA) was used as the curing agent, and a polishing pad was produced in the same manner as in Example 3, except that the number average diameter of pores in the polishing layer and the content of inorganic substances (Si) in the polishing layer were adjusted.

[0188] (Comparative Example 1) As shown in Table 1 below, the type of the solid foaming agent (Expancel 461 DET 40 d25, AkzoNobel, average particle size: 40 μm) was changed, and a polishing pad was produced in the same manner as in Example 3, except that the number average diameter of pores in the polishing layer and the content of inorganic substances were adjusted.

[0189] (Comparative Example 2) As shown in Table 1 below, a polishing pad was manufactured in the same manner as in Comparative Example 1, except that dimethyl thio-toluene diamine (DMTDA) was used as the curing agent, and the number average diameter of pores and the content of inorganic substances in the polishing layer were adjusted.

[0190] The specific components and properties of the polishing layer are summarized in Table 1 below. The parts by weight in Table 1 below are values based on 100 parts by weight of the urethane prepolymer.

[0191] [Table 1]

[0192] (Evaluation) (Experimental Example 1: Preparation of Polishing Slurry) As shown in Table 2 below, a first polishing slurry, a second polishing slurry, and a third polishing slurry were prepared.

[0193] [Table 2]

[0194] (Experimental Example 2: Measurement of Physical Properties of Polishing Pad) [2-1: Measurement of Surface Zeta Potential of Polishing Pad] The surface zeta potential of the polishing pads of the examples and comparative examples was measured using a ZETASIZER (registered trademark) Nano-ZS90 (Malvern), a zeta potential measuring device.

[0195] The zeta potential measuring device is of the Dip cell type, has electrodes at the ends of the barrel (with a test piece attached between them), and includes an avalanche photodiode (APD) detection system.

[0196] Specifically, FIG. 3 shows a schematic diagram showing a surface zeta potential cell. Referring to FIG. 3, the polishing pad samples (4 mm × 5 mm, 20 mm 2 ) obtained in the examples and comparative examples were attached to the sample holder 310 with double-sided tape, and 2 ml of the first polishing slurry, the second polishing slurry, or the third polishing slurry was diluted to the dilution concentration described in Table 2 and placed in a cuvette 330, and the electrophoretic mobility was measured using the Ag / AgCl reference electrode 320. The measured electrophoretic mobility changes as a function of the distance from the sample surface, and the surface zeta potential of the polishing pad was determined by the following formula 1. [Formula 1] Surface zeta potential = (-) Zeta potential of the fixed layer + Zeta potential of the composition

[0197] In the above formula 1, the zeta potential of the fixed layer 110 is obtained by measuring and extrapolating the ion diffusion layer 120 in FIG. 1.

[0198] FIG. 2 is a graph measuring the apparent zeta potential with respect to the surface displacement of the polishing surface in the polishing pad of Example 1. Specifically, the polishing surface of the polishing pad of Example 1 was measured for the apparent zeta potential with respect to the surface displacement using the first polishing slurry in which the zeta potential of the tracer polishing slurry was -41.3 mV, and a graph of the average value and the regression fit therefor is shown. The first surface zeta potential (PZ1), which is the surface zeta potential value derived by the above formula 1 with respect to the first polishing slurry having a zeta potential of -41.3 mV, was measured to be -60.5 mV. At this time, the fixed layer zeta potential was 19.2 mV, the value of the surface equivalent mobility was -4.744 (μmcm / Vs), the value of the surface zeta potential uncertainty was 4.31 (mV), and the value of the surface equivalent mobility uncertainty was 0.3377 (μmcm / Vs).

[0199] By such a method, the surface zeta potential of each polishing pad of the examples and comparative examples measured according to the type of polishing slurry is shown in Table 3 below.

[0200] [2-2: Measurement of polishing rate of tungsten and oxide] <Polishing rate for tungsten (W) film> Using a CMP polishing apparatus, a 300-mm diameter silicon wafer on which a tungsten (W) film was formed by a CVD process was installed. Then, the tungsten film of the silicon wafer was set downward on the surface plate with the polishing pad. Then, the polishing load was adjusted to 2.8 psi, and while introducing a second polishing slurry (colloidal silica slurry) onto the polishing pad at a rate of 190 ml / min, the surface plate was rotated at 115 rpm for 30 seconds to polish the tungsten film. After polishing, the silicon wafer was removed from the carrier, mounted on a rotary dehydrator (spin dryer), washed with purified water (DIW), and then dried with air for 15 seconds. The thickness difference of the dried silicon wafer before and after polishing was measured using a contact surface resistance measuring apparatus (4-probe probe). Then, the polishing rate was calculated using the following Mathematical Formula 1. [Equation 1] Polishing rate (Å / min) = Thickness difference before and after polishing (Å) / Polishing time (min)

[0201] <Polishing rate of oxide (O) film> Also, using the same apparatus, instead of the silicon wafer on which the tungsten film was formed, silicon oxide (SiO x) A silicon wafer with a diameter of 300 mm on which a film was formed was placed. Then, the silicon wafer with the silicon oxide film facing downward was set on the surface plate with the polishing pad. After that, the polishing load was adjusted to 1.4 psi, and while introducing the first polishing slurry (fumed silica slurry) or the third polishing slurry (ceria slurry) onto the polishing pad at a rate of 190 ml / min, the surface plate was rotated at 115 rpm for 60 seconds to polish the silicon oxide film. After polishing, the silicon wafer was removed from the carrier, mounted on a rotary dehydrator, washed with purified water (DIW), and then dried with air for 15 seconds. The difference in thickness before and after polishing of the dried silicon wafer was measured using a spectroscopic interferometric wafer thickness gauge (SI-F80R, manufactured by Keyence). Then, the polishing rate was calculated using the above Mathematical Formula 1.

[0202] [2-3: Measurement of the number of surface defects such as scratches and chatter marks] After performing the CMP process in the same procedure as in Experimental Example 2-2 using the polishing pads of the Examples and Comparative Examples, the number of surface defects such as scratches and chatter marks that appeared on the wafer surface after polishing was measured using a defect inspection apparatus (AIT XP+, manufactured by KLA Tencor) (conditions: threshold 150, die filter threshold 280).

[0203] The scratch means a substantially continuous linear scratch mark, and as an example, it refers to a defect having a shape as shown in FIG. 5.

[0204] On the other hand, the chatter mark means a substantially discontinuous linear scratch mark, and as an example, it refers to a defect having a shape as shown in FIG. 6. The results of the above Experimental Examples were summarized in Table 3 below.

[0205]

Table 3

[0206] As can be seen from Table 3 above, when the surface zeta potential targeted in the present invention is satisfied, it was confirmed that the polishing rate and the effect of reducing surface defects such as scratches and chatter marks are significantly superior compared to the cases where the polishing pads of Comparative Examples 1 and 2 were used.

[0207] Looking specifically, regarding the polishing rate, in the case of the polishing pads of Examples 1 to 5, the polishing rate (OR1) of the polishing pad using the first polishing slurry for the oxide film was 2,894 Å / min to 2,950 Å / min, and the polishing rate (WR2) of the polishing pad using the second polishing slurry for the tungsten film was 780 Å / min to 800 Å / min, and the polishing rate (OR3) of the polishing pad using the third polishing slurry for the oxide film was 2,256 Å / min to 2,583 Å / min. Depending on the type of slurry according to the film quality of the polishing target, each was able to achieve an appropriate polishing rate.

[0208] Also, regarding surface defects such as scratches and chatter marks, when the polishing pads of Examples 1 to 5 were used, the number of surface defects such as scratches and chatter marks appearing on the wafer surface was less than 5 in all cases. However, when the polishing pads of Comparative Examples 1 and 2 were used, it was confirmed that the number of surface defects such as scratches and chatter marks appearing on the wafer surface increased significantly, by more than 9 times compared to the case of using the polishing pads of the examples.

[0209] Considering the above matters, the polishing pad according to the above examples can achieve excellent polishing performance for both tungsten film quality and oxide film quality by controlling the surface zeta potential of the polishing surface and their ratios according to the type of polishing slurry within a specific range, and it was found that it shows an excellent effect in reducing surface defects such as scratches and chatter marks appearing on the surface of the semiconductor substrate. That is, the polishing pad can have the advantage of being applicable to continuous and discontinuous processes for various polishing environments depending on the polishing target of different materials by achieving appropriate polishing performance for both oxide film quality and tungsten film quality with one polishing pad.

[0210] In addition, the polishing pad according to the above embodiment can achieve excellent polishing performance for the oxide film. Specifically, in the bulk process and the fine process for the oxide film, the application of continuous and discontinuous processes is possible, and in any case, by ensuring excellent polishing performance, it can have great advantages in multiple processes.

[0211] In addition, the polishing pad according to the above embodiment can achieve excellent polishing performance in any polishing environment using silica slurry and ceria slurry, and can have the advantage of being applicable to continuous and discontinuous processes for various polishing environments due to different types of slurries.

[0212] Furthermore, the polishing pad according to the above embodiment can achieve excellent polishing performance when the slurry environment is acidic and basic with one pad, or in any polishing environment using silica slurry and ceria slurry.

Explanation of Reference Numerals

[0213] 100, 410: Polishing pad 10: Polishing layer 11: Polishing surface 20: Cushion layer 30: Adhesive layer 110: Fixing layer 120: Ion diffusion layer 130: Slipping plane 310: Sample holder 320: Electrode 330: Cuvette 420: Surface plate 430: Semiconductor substrate 440: Nozzle 450: Polishing slurry 460: Polishing head 470: Conditioner

Claims

1. comprising a polishing layer, when polishing the polishing surface of the polishing layer using a first composition having a hydrogen ion concentration (pH) of more than 9.5 and 12 or less, the polishing surface has a first surface zeta potential (PZ1) which is a surface zeta potential value of the polishing surface derived by the following formula 1 with respect to the first composition, when polishing the polishing surface of the polishing layer using a third composition having a hydrogen ion concentration (pH) of 7.5 or more and 9.5 or less, the polishing surface has a third surface zeta potential (PZ3) which is a surface zeta potential value of the polishing surface derived by the following formula 1 with respect to the third composition, the IZ1 of the zeta potential value of the fixed layer with respect to the first composition is +5 mV to +30 mV, the IZ3 of the zeta potential value of the fixed layer with respect to the third composition is -15 mV to +10 mV, a polishing pad, wherein the first surface zeta potential (PZ1) and the third surface zeta potential (PZ3) satisfy the following formula 3: [Formula 1] Surface zeta potential = (-) Zeta potential of the fixed layer + Zeta potential of the composition [Formula 3] 1 ≤ PZ1 / PZ3 ≤ 5.

2. the first composition contains silica particles having an average particle diameter of 130 nm to 160 nm and a zeta potential of -50 mV to -30 mV, the third composition contains ceria particles having an average particle diameter of 130 nm to 170 nm and a zeta potential of -55 mV to -35 mV, the polishing pad according to claim 1.

3. the polishing layer contains a cured product of a composition containing a urethane prepolymer, a curing agent, and a foaming agent, the content of the inorganic substance in the polishing layer is 5 ppm to 500 ppm, the polishing pad according to claim 1.

4. the urethane prepolymer has an isocyanate terminal group content (NCO%) of 8% by weight to 10% by weight, the foaming agent contains a solid-phase foaming agent, a gas-phase foaming agent, or a combination thereof having an average particle diameter of 5 μm to 200 μm, the content of the curing agent is 18 parts by weight to 27 parts by weight based on 100 parts by weight of the urethane prepolymer, the polishing layer has a porous structure containing pores having a number average diameter of 10 μm to 40 μm, the polishing pad according to claim 3.

5. assuming the polishing rate of the oxide film with respect to the polishing surface of the polishing layer using the first composition is OR1, and the polishing rate of the oxide film with respect to the polishing surface of the polishing layer using the third composition is OR3, OR1 is 2750 Å / min or more and less than 2955 Å / min, The polishing pad according to claim 1, wherein the OR3 is 2,200 Å / min or more and 2,955 Å / min or less.

6. Providing a polishing pad including a polishing layer; Polishing the object to be polished while relatively rotating the object to be polished so that the surface to be polished of the object to be polished contacts the polishing surface of the polishing layer, wherein the object to be polished includes an oxide film, when the polishing surface of the polishing layer is polished using a first composition having a hydrogen ion concentration (pH) of more than 9.5 and 12 or less, the polishing surface has a first surface zeta potential (PZ1) which is a surface zeta potential value of the polishing surface derived by the following formula 1 with respect to the first composition, when the polishing surface of the polishing layer is polished using a third composition having a hydrogen ion concentration (pH) of 7.5 or more and 9.5 or less, the polishing surface has a third surface zeta potential (PZ3) which is a surface zeta potential value of the polishing surface derived by the following formula 1 with respect to the third composition, IZ1, which is the zeta potential value of the fixed layer with respect to the first composition, is +5 mV to +30 mV, IZ3, which is the zeta potential value of the fixed layer with respect to the third composition, is -15 mV to +10 mV, A method for manufacturing a semiconductor device, wherein the first surface zeta potential (PZ1) and the third surface zeta potential (PZ3) satisfy the following formula 3: [Formula 1] Surface zeta potential = (-) zeta potential of the fixed layer + zeta potential of the composition [Formula 3] 1 ≤ PZ1 / PZ3 ≤ 5.

7. In the step of polishing the object to be polished, supplying any one of a slurry containing silica particles and a slurry containing ceria particles as the slurry for polishing the oxide film, or The method for manufacturing a semiconductor device according to claim 6, further comprising sequentially supplying the slurry containing silica particles and the slurry containing ceria particles to the polishing surface.

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