Composite polishing pad including a highly wear-resistant thin film coating bound by carbon nanotubes and method for manufacturing the same

Abstract

The present invention provides a composite polishing pad for CMP, which includes a soft polymer substrate layer having a plurality of protrusions formed on its upper surface; a carbon nanotube layer having carbon nanotubes embedded and bonded to the upper surface of the substrate layer; and a hard polymer coating layer having carbon nanotubes embedded and bonded to the upper surface of the carbon nanotube layer, the carbon nanotubes protruding outward, and a method for manufacturing the same.

Description

Technical Field

[0001] The present invention relates to a composite polishing pad including a highly wear-resistant thin film coating bound by carbon nanotubes and a method for manufacturing the same.

Background Art

[0002] Chemical Mechanical Polishing (CMP) is a core process for planarizing and mirror-finishing wafers and glass panels, and performs polishing by the mechanical and chemical actions of a polishing pad and a slurry containing nanoparticles.

[0003] FIG. 1 is a schematic diagram of a CMP apparatus. The CMP apparatus performs polishing by pressing the object to be polished onto the surface of a polishing pad (100) fixed to a rotating table (1) with a carrier (3) firmly fixing the object to be polished (2, for example, a wafer). Specifically, while the carrier (3) and the rotating table (1) rotate independently, a liquid slurry (polishing agent) is applied from a nozzle (5) to the polishing pad (100), thereby performing chemical and mechanical polishing. Further, during the polishing process, a conditioner (4) is pressed against the polishing pad (100) at a position separated from the object to be polished (1), roughening the surface of the polishing pad (100) and maintaining the rough surface state of the polishing pad.

[0004] Generally, a polyurethane-based polishing pad is used in the CMP apparatus. However, conventional polyurethane-based polishing pads have the disadvantages that wear progresses rapidly due to friction with high-hardness nanoparticles, the object to be polished, and a diamond conditioner during the polishing process, and the lifespan is short. Further, due to irregular surface roughness, there is a disadvantage that uniform polishing performance cannot be guaranteed.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] The present invention was devised to solve the above problems of the prior art, and an object thereof is to provide a composite polishing pad for CMP with significantly improved polishing performance and lifespan, and an efficient manufacturing method thereof.

Means for Solving the Problems

[0007] To achieve the above object, the present invention provides a soft polymer base material layer including a number of protrusions formed on the upper surface; a carbon nanotube layer including carbon nanotubes embedded and bonded on the upper part of the base material layer; and a hard polymer coating layer in which carbon nanotubes protruding to the outside are embedded and bonded on the upper part of the carbon nanotube layer; a composite polishing pad for CMP.

[0008] In one embodiment of the present invention, the carbon nanotube layer may include carbon nanotubes vertically embedded in the soft polymer base material layer and the hard polymer coating layer.

[0009] In one embodiment of the present invention, the carbon nanotubes vertically embedded in the soft polymer base material layer and the hard polymer coating layer may be 50% or more of the total carbon nanotubes in the carbon nanotube layer.

[0010] In one physical embodiment of the present invention, the carbon nanotubes in the carbon nanotube layer may be embedded in an irregular net form structure in the soft polymer base material layer and the hard polymer coating layer.

[0011] In one embodiment of the present invention, the irregular net form structure may be a structure formed by scattering carbon nanotubes so that some of them overlap with each other.

[0012] In one embodiment of the present invention, the soft polymer base material layer may have a Shore hardness of 20D to 45D, and the hard polymer coating layer may have a Shore hardness of 45D to 70D.

[0013] In one embodiment of the present invention, the protrusions may have a maximum width of 10 μm to 500 μm and a height of 3 μm to 150 μm. In one embodiment of the present invention, the carbon nanotubes may have a diameter of 1 nm to 50 nm and a length of 1 μm to 30 μm.

[0014] In one embodiment of the present invention, the thickness of the hard polymer coating layer may be 1 μm to 50 μm. In one embodiment of the present invention, the protrusions may be similar to a hemispherical shape.

[0015] Also, the present invention provides (a) preparing a substrate on which carbon nanotubes are arranged vertically; (b) coating a soft polymer on the upper part of the carbon nanotubes to form a soft polymer base material layer with a flat upper surface; (c) separating and removing the substrate from the carbon nanotubes; (d) plasma etching the surface from which the substrate has been removed to remove a certain thickness of the soft polymer base material, thereby exposing a part of the carbon nanotubes; (e) coating a hard polymer on the surface where the carbon nanotubes are exposed so that the upper surface is flat to form a hard polymer coating layer; and (f) Embossing is performed in the direction of the upper surface of the hard polymer coating layer to form a number of protrusions including a soft polymer base material layer, a carbon nanotube layer arranged vertically, and a hard polymer coating layer; and a method for manufacturing a composite polishing pad for CMP is provided.

[0016] In one embodiment of the present invention, the embossing process in step (f) may be performed by pressing the upper surface of the hard polymer coating layer with a mold in which a number of protrusions are engraved under heating conditions. In one embodiment of the present invention, steps (b) and (e) may be performed in a vacuum state.

[0017] Also, the present invention (a) Sprinkling carbon nanotubes on a mold in which a number of protrusions are engraved so that a part of them overlaps each other; (b) Coating a soft polymer on the upper part of the carbon nanotubes to form a soft polymer base material layer with a flat upper surface; (c) Demolding the mold; (d) Plasma etching the demolded surface to remove a certain thickness of the soft polymer base material, thereby exposing a part of the carbon nanotubes; and (e) Coating a hard polymer on the surface where the carbon nanotubes are exposed to form a hard polymer coating layer; and a method for manufacturing a composite polishing pad for CMP is provided.

[0018] Also, the present invention (a) Sprinkling carbon nanotubes on a substrate so that a part of them overlaps each other; (b) Coating a soft polymer on the upper part of the carbon nanotubes to form a soft polymer base material layer with a flat upper surface; (c) Separating and removing the substrate from the carbon nanotubes; (d) Plasma etching the surface from which the substrate has been removed to remove a certain thickness of the soft polymer substrate, thereby exposing a part of the carbon nanotubes; (e) Coating the surface on which the carbon nanotubes are exposed with a hard polymer so that the upper surface is flat to form a hard polymer coating layer; and (f) Performing an embossing process in the direction of the upper surface of the hard polymer coating layer to form a number of protrusions including a soft polymer substrate layer, a vertically arranged carbon nanotube layer, and a hard polymer coating layer; A method for manufacturing a composite polishing pad for CMP is provided.

[0019] In one embodiment of the present invention, the embossing process in step (f) may be performed by pressing the upper surface of the hard polymer coating layer with a mold in which a number of protrusions are engraved under heating conditions. In one embodiment of the present invention, steps (b) and (e) may be performed in a vacuum state.

Advantages of the Invention

[0020] The composite polishing pad for CMP of the present invention includes a soft polymer substrate layer and a hard polymer coating layer bound by carbon nanotubes, thereby providing improved polishing performance and lifespan.

[0021] Also, the method for manufacturing a composite polishing pad for CMP of the present invention provides a method capable of efficiently manufacturing the polishing pad.

Brief Description of the Drawings

[0022]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Embodiments for Carrying Out the Invention

[0023] Hereinafter, the embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those having ordinary knowledge in the technical field to which the present invention pertains can easily implement it. However, the present invention can be implemented in various different forms and is not limited to the embodiments described herein. The same reference numerals are assigned to similar parts throughout the specification.

[0024] When a certain component is referred to as being "connected to, provided with, or provided on" another component, it should be understood that it may be directly connected or provided on the other component, but other components may also exist therebetween.

[0025] The composite polishing pad for CMP of the present invention, as shown in FIGS. 2 to 5, A soft polymer base material layer (10) including a large number of protrusions formed on the upper surface; A carbon nanotube layer (20) including carbon nanotubes embedded and bonded on the upper part of the substrate layer; and A hard polymer coating layer (30) in which carbon nanotubes protruding to the outside are embedded and bonded on the upper part of the carbon nanotube layer, characterized by including the same.

[0026] FIG. 6 shows the contact modes of fine protrusions, abrasive particles, and an object to be polished (e.g., a wafer) that change depending on the mechanical properties of the fine protrusions provided on the polishing pad.

[0027] As shown in FIG. 6(a), in the case of fine protrusions having mechanically soft physical properties, deformation is easy and they have a wide contact area, but since sufficient load cannot be applied to the abrasive particles, the surface of the object to be polished cannot be pressed in and polished. Also, they are prone to wear and have the drawback that continuous use as a polishing pad is impossible.

[0028] On the other hand, in the case of fine protrusions having mechanically strong physical properties (e.g., fine protrusions made of a material with high wear resistance), as shown in FIG. 6(b), there is an advantage that a load can be applied to the abrasive particles and the surface of the object to be polished can be deeply pressed in and polished, but there is a drawback that a wide contact area cannot be formed with the object to be polished.

[0029] Therefore, the researchers of the present invention made efforts to provide a polishing pad having fine protrusions capable of applying sufficient load to the abrasive particles while ensuring a wide contact area with the object to be polished. As a result, as shown in FIG. 6(c), when a coating layer is formed of a material having mechanically strong physical properties (e.g., a material with high wear resistance) on the surface of fine protrusions having mechanically soft physical properties, it was found that the above-described effects can be obtained.

[0030] That is, when using a polishing pad including the above-described fine protrusions, a wide contact area can be ensured by the fine protrusion portions made of a soft material, and the abrasive particles can be deeply pressed in by the high wear-resistant coating layer on the surface. Therefore, it is also possible to improve the polishing efficiency and extend the life of the polishing pad.

[0031] However, in the case of the fine protrusions having the above structure (FIG. 6(c)), although they provide an excellent effect compared to the conventional fine protrusions, since the material of the base portion of the fine protrusions and the material of the coating layer are different, there is a drawback that the bonding force between them is weak. That is, when using a polishing pad having fine protrusions of such a structure in an actual polishing process, there is a drawback that the coating portion is separated from the base material and it is difficult to use for a long time. Also, in the case of a coating layer with strong mechanical properties, the gripping force of the abrasive particles is insufficient, which may reduce the polishing efficiency.

[0032] Therefore, in order to solve such drawbacks, the composite polishing pad of the present invention has a feature of including a carbon nanotube layer (20) formed by embedding carbon nanotubes in a soft polymer base layer (10) and a hard polymer coating layer (30) as shown in FIGS. 2 to 5.

[0033] The composite polishing pad of the present invention has a feature of having a wide contact area with the object to be polished and being able to deeply press abrasive particles into the object to be polished due to the above-described characteristic configuration. Also, since the soft polymer base layer and the hard polymer coating layer are bound by carbon nanotubes to form a strong bond, it has a feature that the lifespan is significantly extended. That is, since the carbon nanotube layer (20) increases the bonding area between the soft polymer base layer (10) and the hard polymer coating layer (30), the bonding force increases, and accordingly, the lifespan of the polishing pad is significantly extended.

[0034] Also, when abrasive particles are pressed into the hard polymer coating layer, the carbon nanotubes located in the hard polymer coating layer function to support the abrasive particles, thereby improving the gripping force of the abrasive particles, and accordingly, providing an effect of improving the polishing efficiency.

[0035] In one embodiment of the present invention, as shown in FIGS. 2 and 3, the carbon nanotube layer (20) may include carbon nanotubes (22) vertically embedded in the soft polymer substrate layer (10) and the hard polymer coating layer (30).

[0036] In one embodiment of the present invention, the carbon nanotubes vertically embedded in the soft polymer substrate layer (10) and the hard polymer coating layer (30) may be 50% or more, preferably 60% or more, more preferably 80% or more, and still more preferably 90% or more of the total carbon nanotubes in the carbon nanotube layer.

[0037] The vertically arranged carbon nanotubes can be obtained, for example, by a method of vapor-growing carbon nanotubes so as to have a certain interval on a substrate. Embedding and binding the carbon nanotubes on the upper part of the soft polymer substrate layer (10) to form the carbon nanotube layer (20) can be achieved, for example, by coating a soft polymer on a substrate with vertically arranged carbon nanotubes to a thickness higher than that of the carbon nanotubes, removing the substrate, and then plasma-etching the surface from which the substrate has been removed to remove the soft polymer substrate layer to a certain thickness. These methods will be described in detail below.

[0038] In one embodiment of the present invention, the vertically arranged state does not mean a strictly vertical arrangement, but means that the carbon nanotubes are artificially arranged close to the vertical direction. The vertically arranged state includes, for example, those in which the carbon nanotubes are arranged in a spike shape on the soft polymer substrate layer. Specifically, the vertically arranged state may be such that the angle formed by the carbon nanotubes with the upper surface of the soft polymer substrate layer is 60 degrees to 90 degrees, 70 degrees to 90 degrees, or 80 degrees to 90 degrees.

[0039] In one embodiment of the present invention, the carbon nanotubes of the carbon nanotube layer (20) may be embedded in an irregular net form structure in the soft polymer base layer (10) and the hard polymer coating layer (30) as shown in FIGS. 4 and 5.

[0040] The irregular net form structure may be a structure formed by scattering carbon nanotubes so that a part of them overlaps. The meaning of the above-mentioned scattering is to disperse and arrange the carbon nanotubes, and the meaning of the above-mentioned overlap means that a part of the carbon nanotubes overlaps to strengthen the three-dimensional structure.

[0041] In one embodiment of the present invention, the soft polymer base layer (10) may have a Shore hardness of 20D to 45D, and the hard polymer coating layer (30) may have a Shore hardness of 45D to 70D. When the hardness of the soft polymer base layer and the hard polymer coating layer satisfies the above range, not only can the contact area between the protrusion and the object to be polished be widely formed, but also the polishing efficiency can be improved.

[0042] In one embodiment of the present invention, as the material of the soft polymer having a Shore hardness of 20D to 45D forming the soft polymer base layer (10), one or more selected from the group consisting of polyurethane resin, UV curable resin, silicone resin, etc. may be used, but it is not limited thereto. As long as it does not have an adverse effect on the present invention, materials known in this field may be used without limitation.

[0043] Also, as the hard polymer material having a Shore hardness of 45D to 70D forming the hard polymer coating layer (30), one or more selected from the group consisting of polyurethane resin, UV curable resin, silicone resin, etc. may be used, but it is not limited thereto. As long as it does not have an adverse effect on the present invention, materials known in this field may be used without limitation.

[0044] In one embodiment of the present invention, the protrusion may have a maximum width of 10 μm to 500 μm and a height of 3 μm to 150 μm. However, the range is not limited to this range and can be appropriately adjusted according to the object to be polished and the polishing conditions.

[0045] In one embodiment of the present invention, the carbon nanotube may have a diameter of 1 nm to 50 nm and a length of 1 μm to 30 μm. However, the diameter and length are not limited to this range and can be appropriately adjusted according to the object to be polished and the polishing conditions.

[0046] In one embodiment of the present invention, the thickness of the hard polymer coating layer (30) may be 1 μm to 30 μm, more preferably 3 μm to 20 μm. When the thickness of the coating layer is thinner than the thickness, the carbon nanotubes are easily exposed due to wear, which is not preferable. When the thickness is too thick, the gripping force of the abrasive particles by the carbon nanotubes decreases, which is not preferable. However, the range can be appropriately adjusted according to the length of the carbon nanotubes, the object to be polished, and the polishing conditions.

[0047] In one embodiment of the present invention, the thickness of the soft polymer base material layer (10) may be 1 mm to 20 mm, more preferably 2 mm to 10 mm.

[0048] In one embodiment of the present invention, the protrusion may have a shape similar to, for example, a hemisphere, but its shape is not particularly limited. As shown in FIGS. 2 to 5, the protrusion includes a soft polymer base material layer (10), a carbon nanotube layer (20) arranged vertically, and a hard polymer coating layer (30), and protrudes upward from the composite polishing pad.

[0049] In one embodiment of the present invention, as shown in FIGS. 2 and 5, the soft polymer substrate layer (10) and the hard polymer coating layer (30) may have a structure in which they are in contact with each other in the space between the carbon nanotubes disposed in the carbon nanotube layer (20).

[0050] In one embodiment of the present invention, the composite polishing pad may have a structure in which there are no pores between the soft polymer substrate layer (10) and the carbon nanotubes embedded and bound in the substrate layer (10). When there are no such pores, it is preferable because the soft polymer substrate layer (10) and the carbon nanotubes embedded and bound in the substrate layer (10) can be more firmly bound.

[0051] Also, the composite polishing pad may have a structure in which there are no pores between the hard polymer coating layer (30) and the carbon nanotubes embedded and bound in the coating layer (30). When there are no such pores, it is preferable because the hard polymer coating layer (10) and the carbon nanotubes embedded and bound in the coating layer (10) can be more firmly bound.

[0052] Also, as a whole, the composite polishing pad may have a structure in which there are no pores at the interfaces of the substrate layer (10), the carbon nanotube layer (20), and the coating layer (30). Such a structure can be formed by forming the bond between the layers in a vacuum as described below. The expression that there are no pores may sometimes mean that there are substantially no pores.

[0053] The present invention also provides a method for manufacturing a composite polishing pad for CMP, and the manufacturing method may include the following steps (a) to (f) as shown in FIG. 7: (a) Preparing a substrate on which carbon nanotubes are arranged in the vertical direction; (b) Coating a soft polymer on the upper part of the carbon nanotubes to form a soft polymer substrate layer having a flat upper surface; (c) separating and removing the substrate from the carbon nanotubes; (d) exposing a part of the carbon nanotubes by plasma etching the surface from which the substrate has been removed to remove a certain thickness of the soft polymer substrate; (e) forming a hard polymer coating layer by coating a hard polymer on the surface where the carbon nanotubes are exposed so that the upper surface is flat; and (f) performing an embossing process in the direction of the upper surface of the hard polymer coating layer to form a number of protrusions including a soft polymer substrate layer, a vertically arranged carbon nanotube layer, and a hard polymer coating layer

[0054] The content related to the above-mentioned composite polishing pad for CMP can be directly applied to the above manufacturing method. Therefore, repeated descriptions are omitted.

[0055] The substrate on which the carbon nanotubes are vertically arranged in the step (a) can be produced, for example, by forming a catalyst layer such as Fe / Al2O3 by Physical Vapor Deposition (PVD) on a substrate such as a silicon substrate or a metal foil substrate, and then forming vertically arranged carbon nanotubes by Chemical Vapor Deposition (CVD) on the substrate on which the catalyst layer is formed. However, the manufacturing method of the substrate on which the carbon nanotubes are vertically arranged is not limited to the above method, and it may be manufactured by a method known in this field.

[0056] The coating in the steps (b) and (e) can be carried out by a method known in this field. For example, it may be coated by a method such as spin coating or spray coating, or other known coating methods in this field may be used for coating.

[0057] The substrate separation in the step (c) may be carried out, for example, by mechanical silicon separation (release), silicon etching or the like. The plasma etching method in the step (d) is not particularly limited and can be performed using methods known in this field.

[0058] The embossing process in the step (f) may be performed by pressing the upper surface of the hard polymer coating layer with a mold in which a large number of protrusions are engraved under heating conditions. Specifically, as shown in FIG. 7, it can be performed using a mold in which a micro pattern is formed. At this time, heat can be supplied to the mold, and the embossing process can be performed in a state where the mold is heated. At this time, the temperature of the mold may be 200 to 250 ° C, but is not limited thereto. The mold may be made of a metal material such as nickel or copper, and the micro pattern may be fabricated by utilizing a Micro Electro-Mechanical System (MEMS) process.

[0059] The composite polishing pad manufactured by the above method has protrusions as shown in the SEM photograph of FIG. 9. Also, it has an internal structure as shown in FIG. 10. Referring to FIG. 10, it can be confirmed that the composite polishing pad of the present invention is in a form in which the soft polymer base layer (10) and the hard polymer coating layer (30) are bonded by carbon nanotubes (22).

[0060] In one embodiment of the present invention, one or more of the steps (b) and (e) may be performed in a vacuum state. When the coating is performed in a vacuum state, it is possible to prevent the formation of pores between the carbon nanotubes and the soft polymer base layer, and thus it is preferable because the carbon nanotubes can be more strongly embedded and bonded.

[0061] The present invention also provides a method for manufacturing another CMP composite polishing pad, and the manufacturing method may include the following steps (a) to (e) as shown in FIG. 8: (a) A step of sprinkling carbon nanotubes on a mold in which a large number of protrusions are engraved so that a part of them overlaps with each other; (b) Coating a soft polymer on top of the carbon nanotubes to form a soft polymer substrate layer with a flat top surface; (c) Removing the mold; (d) Exposing a part of the carbon nanotubes by plasma etching the demolded surface to remove a certain thickness of the soft polymer substrate; and (e) Coating a hard polymer on the surface where the carbon nanotubes are exposed to form a hard polymer coating layer The content related to the above-mentioned composite polishing pad for CMP and its manufacturing method can be directly applied to the above manufacturing method. Therefore, duplicate descriptions are omitted.

[0062] The method of scattering the carbon nanotubes in step (a) so that they partially overlap each other can be carried out by a method known in this field. For example, as shown in FIG. 8, it can be carried out by spraying the carbon nanotubes into the mold through a nozzle. At this time, the carbon nanotubes can also be sprayed in a form dispersed in a solvent. Examples of the solvent include, but are not limited to, water, ethanol, isopropyl alcohol, etc. Steps (b), (d), and (e) can be carried out in the same manner as the other methods described above.

[0063] The present invention also provides a manufacturing method for other composite polishing pads for CMP, and the manufacturing method can include the following steps (a) to (f): (a) Scattering carbon nanotubes on a substrate so that they partially overlap each other; (b) Coating a soft polymer on top of the carbon nanotubes to form a soft polymer substrate layer with a flat top surface; (c) Separating and removing the substrate from the carbon nanotubes; (d) Exposing a part of the carbon nanotubes by plasma etching the surface from which the substrate has been removed to remove a certain thickness of the soft polymer substrate; (e) Forming a hard polymer coating layer by coating a hard polymer on the exposed surface of the carbon nanotube so that the upper surface is flat; and (f) Performing embossing in the direction of the upper surface of the hard polymer coating layer to form a number of protrusions including a soft polymer base layer, a carbon nanotube layer arranged vertically, and a hard polymer coating layer

[0064] The content related to the above-mentioned composite polishing pad for CMP and other manufacturing methods can be directly applied to the above manufacturing method. Therefore, duplicate descriptions are omitted.

[0065] Hereinafter, examples will be given for a specific description of the present invention. However, the examples according to the present invention can be deformed into various other forms, and the scope of the present invention should not be construed as being limited to the examples detailed below. The examples of the present invention are provided to more fully explain the present invention to those having average knowledge in the industry.

Example

[0066] Example 1: Manufacture of Composite Polishing Pad An Fe / Al2O3 catalyst layer was deposited on a silicon substrate with a thickness of 525 μm by physical vapor deposition (PVD), and a substrate on which multi-walled carbon nanotubes with a diameter of about 10 nm and a length of 3 μm arranged vertically were formed by chemical vapor deposition (CVD) was prepared on the substrate. At this time, it was confirmed that the carbon nanotubes were formed at a density of ~10 11 pieces / cm 2 .

[0067] On the upper part of the carbon nanotubes arranged vertically on the substrate, a polyurethane resin with a Shore hardness of 30D (trade name: Smooth-Cast TM30D, Manufacturer: Smooth-On) was applied under a vacuum atmosphere to form a soft polymer base layer with a thickness of 5 mm based on the upper end of the carbon nanotubes.

[0068] After curing the soft polymer base layer, the silicon was mechanically separated, and the carbon nanotubes were transferred to the polyurethane. Next, the surface from which the substrate was removed was plasma-etched to remove the soft polymer base material with a thickness of 1 μm, exposing the carbon nanotubes. Then, a polyurethane resin (trade name: Smooth-Cast TM 45D, Manufacturer: Smooth-On) was applied by spin coating under a vacuum atmosphere to form a hard polymer coating layer with a thickness of 5 μm based on the upper end of the carbon nanotubes.

[0069] After curing the hard polymer coating layer, a mold with a large number of hemispherical protrusions with a radius of 50 μm was used for pressing at 200 °C to perform an embossing process to manufacture the composite polishing pad of the present invention.

[0070] Example 2: Manufacture of Composite Polishing Pad The carbon nanotubes were dispersed in isopropyl alcohol to prepare a carbon nanotube dispersion. Next, the dispersion was applied to a mold with a large number of hemispherical protrusions with a radius of 50 μm using a pneumatic nozzle. A polyurethane resin (50 μm) with a shore hardness of 30D was applied under a vacuum atmosphere on the mold coated with the carbon nanotubes to form a soft polymer base layer with a thickness of 5 mm based on the upper end of the carbon nanotubes.

[0071] After curing the soft polymer base layer, the mold was separated and removed. Next, the surface from which the mold was removed was plasma-etched to remove the soft polymer base material with a thickness of 1 μm, exposing the carbon nanotubes. Then, a polyurethane resin (trade name: Smooth-Cast with a shore hardness of 45D was applied to the surface where the carbon nanotubes were exposed. TM45D, Manufacturer: Smooth-On) was applied by spin coating to form a hard polymer coating layer with a thickness of 5 μm based on the upper end of the carbon nanotube.

[0072] Example 3: Manufacture of Composite Polishing Pad Carbon nanotubes were dispersed in isopropyl alcohol to prepare a carbon nanotube dispersion. Next, the dispersion was applied onto a polypropylene substrate placed on a hot plate heated to 60 °C using a pneumatic nozzle. On the mold coated with the carbon nanotubes, a polyurethane resin (trade name: Smooth-Cast TM 30D, Manufacturer: Smooth-On) was applied under a vacuum atmosphere to form a soft polymer base layer with a thickness of 5 mm based on the upper end of the carbon nanotube.

[0073] After curing the soft polymer base layer, the substrate was separated and removed. Next, the surface from which the substrate was removed was plasma-etched to remove the soft polymer base material with a thickness of 1 μm, exposing the carbon nanotubes. Then, a polyurethane resin (trade name: Smooth-Cast TM 45D, Manufacturer: Smooth-On) was applied by spin coating to form a hard polymer coating layer with a thickness of 5 μm based on the upper end of the carbon nanotube.

[0074] After curing the hard polymer coating layer, a mold with a large number of hemispherical protrusions with a radius of 50 μm was used for pressing at 200 °C to perform an embossing process, manufacturing the composite polishing pad of the present invention.

[0075] Comparative Example 1: Manufacture of Composite Polishing Pad A polyurethane resin (trade name: Smooth-Cast TM 30D, Manufacturer: Smooth-On) was applied to form a soft polymer base layer with a thickness of 5 mm.

[0076] After curing the soft polymer base material layer, a polyurethane resin (trade name: Smooth-Cast TM 45D, manufacturer: Smooth-On) with a Shore hardness of 45D was applied on the upper part of the soft polymer base material layer to form a hard polymer coating layer with a thickness of 5 μm.

[0077] After curing the hard polymer coating layer, using a mold with a large number of hemispherical protrusions with a radius of 50 μm engraved, it was pressed at 200 °C to perform an embossing process to manufacture a composite polishing pad.

Explanation of symbols

[0078] 1: Rotating table 2: Wafer 3: Carrier (rotating head) 4: Conditioner 5: Nozzle 10: Soft polymer base material layer 20: Carbon nanotube layer 22: Carbon nanotube 30: Hard polymer coating layer 100: Composite polishing pad

Claims

1. A soft polymer substrate layer including a number of protrusions formed on an upper surface; A carbon nanotube layer including carbon nanotubes embedded and bonded on top of the soft polymer substrate layer; and A hard polymer coating layer in which the carbon nanotubes protruding to the outside are embedded and bonded on top of the carbon nanotube layer; including, The shore hardness of the soft polymer substrate layer is 20D to 45D, and the shore hardness of the hard polymer coating layer is 45D to 70D, The protrusions have a maximum width of 10 μm to 500 μm and a height of 3 μm to 150 μm, The thickness of the hard polymer coating layer is 1 μm to 30 μm, and the hard polymer coating layer is a composite polishing pad for CMP formed so that the carbon nanotubes are not exposed.

2. The carbon nanotube layer of the composite polishing pad for CMP according to claim 1, characterized in that it includes the carbon nanotubes embedded in a direction perpendicular to the soft polymer substrate layer and the hard polymer coating layer.

3. The carbon nanotubes embedded in a direction perpendicular to the soft polymer substrate layer and the hard polymer coating layer are more than 50% of the total carbon nanotubes in the carbon nanotube layer, the composite polishing pad for CMP according to claim 2.

4. The carbon nanotubes of the carbon nanotube layer are embedded in an irregular net form structure in the soft polymer substrate layer and the hard polymer coating layer, the composite polishing pad for CMP according to claim 1.

5. The irregular net form structure is a structure formed by scattering the carbon nanotubes so that some of them overlap each other, the composite polishing pad for CMP according to claim 4.

6. The carbon nanotubes have a diameter of 1 nm to 50 nm and a length of 1 μm to 30 μm, the composite polishing pad for CMP according to claim 1.

7. The protrusions are similar hemispherical shapes, the composite polishing pad for CMP according to claim 1.

8. (a) Preparing a substrate on which carbon nanotubes are arranged vertically; Step (b): Coating a soft polymer on top of the carbon nanotubes to form a soft polymer substrate layer with a flat upper surface; Step (c): Separating and removing the substrate from the carbon nanotubes; Step (d): Plasma etching the surface from which the substrate has been removed to remove a certain thickness of the soft polymer substrate layer, thereby exposing a part of the carbon nanotubes; Step (e): Coating a hard polymer on the surface where the carbon nanotubes are exposed with a flat upper surface to form a hard polymer coating layer; and Step (f): Performing an embossing process in the direction of the upper surface of the hard polymer coating layer to form a number of protrusions including the soft polymer substrate layer, a carbon nanotube layer in which the carbon nanotubes are arranged vertically, and the hard polymer coating layer; A method for manufacturing a composite polishing pad for CMP.

9. The embossing process in step (f) is performed by pressing the upper surface of the hard polymer coating layer with a mold in which a number of protrusions are engraved under heating conditions. The manufacturing method of the composite polishing pad for CMP according to claim 8.

10. Steps (b) and (e) are performed in a vacuum state. The manufacturing method of the composite polishing pad for CMP according to claim 8.

11. Step (a): Sprinkling carbon nanotubes on a mold in which a number of protrusions are engraved so that a part of them overlaps each other; Step (b): Coating a soft polymer on top of the carbon nanotubes to form a soft polymer substrate layer with a flat upper surface; Step (c): Demolding the mold; Step (d): Plasma etching the surface from which the mold has been demolded to remove a certain thickness of the soft polymer substrate layer, thereby exposing a part of the carbon nanotubes; and Step (e): Coating a hard polymer on the surface where the carbon nanotubes are exposed to form a hard polymer coating layer; A method for manufacturing a composite polishing pad for CMP.

12. Step (a): Sprinkling carbon nanotubes on a substrate so that a part of them overlaps each other; Step (b): Coating a soft polymer on top of the carbon nanotubes to form a soft polymer substrate layer with a flat upper surface; Step (c): Separating and removing the substrate from the carbon nanotubes; Step (d): Plasma etching the surface from which the substrate has been removed to remove a certain thickness of the soft polymer base material layer, thereby exposing a part of the carbon nanotubes; Step (e): Coating a hard polymer on the surface where the carbon nanotubes are exposed such that the upper surface is flat to form a hard polymer coating layer; and Step (f): Performing an embossing process in the direction of the upper surface of the hard polymer coating layer to form a number of protrusions including the soft polymer base material layer, a carbon nanotube layer in which the carbon nanotubes are arranged vertically, and the hard polymer coating layer; A method for manufacturing a composite polishing pad for CMP, comprising the steps.

13. The embossing process in step (f) is performed by pressing the upper surface of the hard polymer coating layer under heating conditions with a mold in which the number of protrusions are engraved, according to the method for manufacturing a composite polishing pad for CMP according to claim 12.

14. The steps (b) and (e) are performed in a vacuum state, according to the method for manufacturing a composite polishing pad for CMP according to claim 11 or 12.

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