Abrasive pad

Abstract

The object of this invention is to provide an abrasive pad that can improve end-collapse and / or enhance step elimination performance without altering the physical properties or bubble structure of the abrasive layer. An abrasive pad comprises: an abrasive layer having an abrasive surface for abrading a workpiece; and a buffer layer disposed on the side of the abrasive layer opposite to the abrasive surface. The maximum value of tanδ (measured at 100–1000 rad / s) is defined as the ratio (tanδ) of the storage modulus E' to the loss modulus E” of the entire abrasive pad, obtained through a dynamic viscoelastic test conducted in bending mode using dispersion at 25°C. max100‑1000 ) relative to the maximum value of tanδ measured in the range of 1–10 rad / s (tanδ max1‑10 The ratio of ) is 0.75 to 1.30.

Description

Technical Field

[0001] This invention relates to polishing pads. More specifically, this invention relates to polishing pads that are well-suited for polishing optical materials, semiconductor wafers, semiconductor devices, hard disk substrates, and the like. Background Technology

[0002] Chemical mechanical polishing (CMP) is a commonly used polishing method for planarizing the surfaces of optical materials, semiconductor wafers, semiconductor devices, and hard disk substrates.

[0003] use Figure 1 This section explains the CMP method. Like... Figure 1 Thus, the grinding apparatus 1 for performing the CMP method includes a grinding pad 3, which is held in a manner that prevents the holding platform 16 and the workpiece 8 from deviating. Figure 1 The workpiece 8 (not shown) is brought into contact with the grinding surface, and includes a grinding layer 4 for grinding and a buffer layer 6 supporting the grinding layer 4. The grinding pad 3 is driven to rotate while the workpiece 8 is pressed, grinding the workpiece 8. At this time, a slurry 9 is supplied between the grinding pad 3 and the workpiece 8. The slurry 9 is a mixture (dispersion) of water and various chemical components or hard micro-abrasive particles. By allowing the chemical components or abrasive particles to flow, the grinding effect is increased through relative movement with the workpiece 8. The slurry 9 is supplied to and discharged from the grinding surface through grooves or holes.

[0004] However, as for the aforementioned abrasive pad 3, conventional abrasive pads using polyurethane foam for the abrasive layer 4 have been used. However, the abrasive layer 4 follows the shape of the edge of the workpiece 8 during abrasion, resulting in… Figure 2 The edge of the object being ground 8 shown is significantly ground down compared to the center, exhibiting an "end collapse edge" ( Figure 2 The over-grinding phenomenon is described in section 8a). For a workpiece ground using existing techniques, the vertical axis represents the grinding rate (RR), and the horizontal axis represents the distance along a straight line passing through the center of the workpiece 8 (where "0" on the horizontal axis represents the center of the workpiece). Figure 3 As can be seen from this, the grinding rate at both ends is greater than that at other parts, resulting in edge collapse at the ends. This edge collapse, especially when the grinding rate at the outermost edge (outer periphery) of the workpiece is more than 1.5 times that of the other parts, sometimes poses a problem in semiconductor polishing (particularly oxide film polishing processes).

[0005] In order to address the above-mentioned end collapse, which is a phenomenon of over-polishing, Patent Literature 1 discloses a polishing pad in which the structure of bubbles in a foamed body is made into a specific structure, thereby controlling the hardness of a polishing layer within a certain range, suppressing the occurrence of polishing damage and preventing end collapse.

[0006] Patent Literature 2 discloses a polishing pad in which the hardness and breaking strength of a polishing layer are made to be within a prescribed range, thereby having no problem of end collapse.

[0007] Further, as a polishing pad for CMP, a polishing pad in which a foamed polyurethane is used for a polishing layer has been used in the past, but in recent years, as the wiring of a semiconductor device is becoming finer, improvement in planarization and step performance of a wafer having a pattern and the like is also required.

[0008] For example, Patent Literature 3 discloses a polishing pad in which DMA-measured storage elastic modulus (E') and the like of a polishing layer are made to be within a specific range, thereby exhibiting high rigidity, and in particular, due to high energy dissipation in compression, exhibiting less dishing of metal characteristics, good planarization, and low defectivity.

[0009] In addition, Patent Literature 4 discloses a polishing pad in which, as a high-molecular-weight polyol of a prepolymer that is a polishing layer material, a mixture of PPG and PTMG is used, thereby achieving high planarization efficiency and low defectivity.

[0010] Prior Art Documents

[0011] Patent Literature

[0012] Patent Literature 1: Japanese Patent Application Publication No. 2012-714

[0013] Patent Literature 2: Japanese Patent Application Publication No. 2016-190313

[0014] Patent Literature 3: Japanese Patent Application Laid-Open No. 2004-507076

[0015] Patent Literature 4: Japanese Patent Application Publication No. 2018-43342 SUMMARY

[0016] However, the polishing pads described in the above-mentioned Patent Literatures 1 and 2 need to make the physical properties and bubble structure of a polishing layer specific, and even though improvement in end collapse can be achieved, other polishing performance is sometimes deteriorated.

[0017] In addition, the polishing pad described in Patent Literature 3 was investigated, and as a result, the step elimination performance was insufficient. This is considered to be because the DMA characteristics of only the polishing layer were focused on, and the measurement frequency was solved using only the frequency 10 rad / s of the center portion of the polishing pad. In addition, the polishing pad described in Patent Literature 4 is obtained by mixing PPG (polypropylene glycol) in PTMG (polytetramethylene ether glycol), which is a material used as a polishing pad in the past, and due to the addition of PPG, the structure of the soft segment of the polyurethane constituting the polishing layer changes, and thus the physical properties such as hardness change, and sometimes other polishing characteristics are insufficient.

[0018] The present application was implemented in view of the above problems, and aims to provide a polishing pad in which the improvement of the end collapse is achieved without greatly changing the physical properties and the bubble structure of the polishing layer, and the step elimination performance is improved without greatly changing the composition and the physical properties of the polishing layer.

[0019] The inventors of the present application conducted intensive research, and as a result, found a polishing pad in which the end collapse is suppressed and / or the step elimination performance is improved, and thus the present application was achieved.

[0020] The present application includes the following aspects.

[0021] [1] A polishing pad characterized by comprising:

[0022] a polishing layer having a polishing surface for polishing a polishing object, and a cushion layer disposed on the side of the polishing layer opposite to the polishing surface,

[0023] The ratio of the maximum value of tan δ (tan δ max100-1000 ) measured at 100 to 1000 rad / s to the maximum value of tan δ (tan δ max1-10 ) measured at 1 to 10 rad / s is 0.75 to 1.30.

[0024] [2] The polishing pad according to [1], characterized in that the ratio of the maximum value of tan δ (tan δ max100-1000 ) measured at 100 to 1000 rad / s to the maximum value of tan δ (tan δ max1-10 ) measured at 1 to 10 rad / s is 0.85 to 1.15.

[0025] [3] The polishing pad according to [1] or [2], characterized in that the ratio of the maximum value to the minimum value of tan δ (tan δ max0.1-10000) / Minimum value (tanδ) min0.1-10000 The value is 1 to 1.3.

[0026] [4] The abrasive pad according to any one of [1] to [3] is characterized in that the difference between the maximum and minimum values ​​of tanδ measured at 0.1 to 10000 rad / s (maximum value (tanδ) max0.1-10000 -Minimum value (tanδ) min0.1-10000 The range is 0 to 0.1.

[0027] [5] An abrasive pad, characterized in that,

[0028] It comprises: a grinding layer having a grinding surface for grinding a workpiece; and a buffer layer disposed on the side of the grinding layer opposite to the grinding surface.

[0029] The abrasive pad is characterized in that...

[0030] Regarding the storage elastic modulus E' when the entire abrasive pad is subjected to a dynamic viscoelastic test using dispersion (25°C) in bending mode, the value of E' at 1000 rad / s (E' 1000 The value of E' at 10 rad / s (E') 10 The ratio of (E') 1000 / E' 10 The value is 1 to 2.

[0031] [6] The abrasive pad according to [5] is characterized in that the value of E' at 1000 rad / s (E' 1000 The value of E' at 10 rad / s (E') 10 The ratio of (E') 1000 / E' 10 The value ranges from 1.4 to 1.9.

[0032] [7] The abrasive pad according to [5] or [6] is characterized in that the abrasive layer is formed of a polyurethane resin containing hollow microspheres.

[0033] [8] The abrasive pad according to any one of [5] to [7] is characterized in that the buffer layer is at least one selected from the group consisting of impregnated nonwoven fabric, sponge material and suede material.

[0034] [9] The polishing pad according to any one of [5] to [8] is characterized in that, when polishing a patterned wafer with steps, in the initial polishing stage before the polishing amount reaches 2000 angstroms, for any patterned wafer with a wiring width of 10 μm to 120 μm, the ratio of the step elimination amount (angstroms) to the polishing amount (angstroms) exceeds 1.

[0035] Invention Effects

[0036] According to the present invention, the grinding pad does not require changes to the physical properties or bubble structure of the grinding layer. By making the ratio of the overall energy storage elastic modulus E' to the loss elastic modulus E”, i.e., tanδ, within a specific range, end collapse can be suppressed.

[0037] Additionally, by setting the value of E' to 1000 rad / s for the entire grinding pad (E' 1000 The value of E' at 10 rad / s (E') 10 The ratio of (E') 1000 / E' 10 Within a specific range, the step elimination performance can be improved without significantly altering the composition and properties of the grinding layer. Attached Figure Description

[0038] Figure 1 This is a perspective view of the grinding device 1.

[0039] Figure 2 This is a side view of the workpiece 8 being ground, which is in a state of edge collapse at the end.

[0040] Figure 3 The curve representing the overall grinding rate of the workpiece 8, which was ground using the prior art (the grinding pad of Comparative Example 1), is a straight line passing through the center of the workpiece 8 (the curve when it was ground for the 50th workpiece).

[0041] Figure 4 These are perspective view (a) and cross-sectional view (b) of the abrasive pad 3 of the present invention.

[0042] Figure 5 This diagram shows the grinding process where the workpiece 8 is positioned within the retaining ring 16A and is being ground on the grinding pad. The arrows in the diagram indicate the rotation directions of the workpiece 8 and the grinding pad 3.

[0043] Figure 6 This is a schematic diagram showing the dynamic viscoelasticity test of the entire abrasive pad 3.

[0044] Figure 7 This is a diagram illustrating the state of the step during a step grinding test.

[0045] Figure 8 This is a graph of tanδ when the dynamic viscoelasticity of the entire abrasive pad of Example 1 was measured in bending mode.

[0046] Figure 9 The curve represents the overall grinding rate of the workpiece 8 along a straight line passing through the center of the workpiece 8 that was ground by the grinding pad of Example 1 (the curve when the 50th workpiece was ground).

[0047] Figure 10 is a graph of tan δ at the time of dynamic viscoelasticity measurement in a bending mode for the entire polishing pad of Example 2.

[0048] Figure 11 is a curve showing the polishing rate of the entire object to be polished at a straight line passing through the center of the object to be polished 8 polished by the polishing pad of Example 2 (curve at the time of polishing of the 50th object to be polished).

[0049] Figure 12 is a graph of tan δ at the time of dynamic viscoelasticity measurement in a bending mode for the polishing layer B of the polishing pad of Example 1 and 2.

[0050] Figure 13 is a graph of tan δ at the time of dynamic viscoelasticity measurement in a bending mode for the entire polishing pad of Comparative Example 1.

[0051] Figure 14 is a graph of E' with respect to frequency at the time of dynamic viscoelasticity measurement in a bending mode for the entire polishing pad of Example 2.

[0052] Figure 15 is a graph of E' with respect to frequency at the time of dynamic viscoelasticity measurement in a bending mode for the entire polishing pad of Example 4.

[0053] Figure 16 is a graph of E' with respect to frequency at the time of dynamic viscoelasticity measurement in a bending mode for the entire polishing pad of Comparative Example 2.

[0054] Figure 17 is a result of step elimination performance test using the polishing pad of Example 2, Example 4, Comparative Example 2 (in the case of an object to be polished using a wiring having a Cu wiring width of 120 μm).

[0055] Figure 18 is a result of step elimination performance test using the polishing pad of Example 2, Example 4, Comparative Example 2 (in the case of an object to be polished using a wiring having an insulating film width of 100 μm with respect to a Cu wiring width of 100 μm).

[0056] Figure 19 is a result of step elimination performance test using the polishing pad of Example 2, Example 4, Comparative Example 2 (in the case of an object to be polished using a wiring having an insulating film width of 50 μm with respect to a Cu wiring width of 50 μm).

[0057] Figure 20 is a result of step elimination performance test using the polishing pad of Example 2, Example 4, Comparative Example 2 (in the case of an object to be polished using a wiring having an insulating film width of 10 μm with respect to a Cu wiring width of 10 μm). DETAILED DESCRIPTION

[0058] Hereinafter, a scheme for implementing the present application will be described, but the present application is not limited to the scheme for implementing the present application.

[0059] <<Abrasive Pad>>

[0060] Employing Figure 4 The structure of the abrasive pad 3 will be described. The abrasive pad 3 includes an abrasive layer 4 and a cushion layer 6 as shown in FIG. 1. Figure 4 The shape of the abrasive pad 3 is preferably a disc shape, but is not particularly limited, and the size (diameter) can be appropriately determined in accordance with the size of the polishing device 1 having the abrasive pad 3, and the like, and for example, can be about 10 cm to 2 m in diameter.

[0061] It should be noted that the abrasive pad 3 of the present application is preferably as shown in FIG. 2. Figure 4 The abrasive layer 4 is adhered to the cushion layer 6 by means of the adhesive layer 7.

[0062] The abrasive pad 3 is adhered to the polishing stage 10 of the polishing device 1 by means of double-sided tape or the like provided to the cushion layer 6. The abrasive pad 3 is driven to rotate in a state in which the object to be polished 8 is pressed by the polishing device 1, and the object to be polished 8 is polished.

[0063] <<Abrasive Layer>>

[0064] (Configuration)

[0065] The abrasive pad 3 has a layer for polishing the object to be polished 8, that is, the abrasive layer 4. As a material constituting the abrasive layer 4, a polyurethane resin, a polyurea resin, and a polyurethane polyurea resin can be preferably used, and a polyurethane resin can be more preferably used.

[0066] The size (diameter) of the abrasive layer 4 is the same as that of the abrasive pad 3, and the diameter can be about 10 cm to 2 m, and the thickness of the abrasive layer 4 can be usually about 1 to 5 mm.

[0067] The abrasive layer 4 rotates together with the polishing stage 10 of the polishing device 1, and the chemical components and the abrasive grains contained in the slurry 9 relatively move together with the object to be polished 8 in a state in which the slurry 9 flows on the polishing stage 10, and thus the object to be polished 8 is polished.

[0068] The hollow microspheres 4A (foaming) are dispersed in the abrasive layer 4.

[0069] (Grooving)

[0070] The surface of the polishing layer 4 on the side of the object to be polished 8 is preferably subjected to groove processing. The groove is not particularly limited and can be any one of a slurry discharge groove that communicates with the surroundings of the polishing layer 4 and a slurry holding groove that does not communicate with the surroundings of the polishing layer 4, and in addition, can have both a slurry discharge groove and a slurry holding groove. As the slurry discharge groove, a lattice-shaped groove, a radial groove, and the like can be given, and as the slurry holding groove, a concentric circle-shaped groove, a perforation (through hole), and the like can be given, and they can be combined.

[0071] Note that in low-pressure polishing processing, since the pressing force against the object to be polished 8 is made small, the land is rotated at high speed from the viewpoint of securing the polishing rate. Therefore, there is a possibility that the so-called water slide phenomenon in which the slurry 9 exists in a layer between the polishing surface and the processed surface and hinders polishing processing occurs. By subjecting the polishing surface to groove processing, this phenomenon can be suppressed. In addition, the discharge of the polishing chips and the movement of the polishing liquid can also be promoted. The cross-sectional shape can be any one of a U shape, a V shape, and a semicircle shape. The pitch, width, and depth of the groove are also not particularly limited. In addition, in order to improve the flatness of the polishing pad 3, a surface grinding treatment such as a polishing treatment can be performed on the side of the polishing surface of the polishing pad 3 to the side opposite to the polishing surface.

[0072] (Shore D hardness)

[0073] The Shore D hardness of the polishing layer 4 of the present application is not particularly limited and is, for example, 20 to 100, preferably 30 to 80, and more preferably 40 to 70. In the case where the Shore D hardness is small, it becomes difficult to flatten the fine irregularities by low-pressure polishing processing. In addition, there are cases where the end portion is affected by the collapse. If the Shore D hardness is too high, the object to be polished 8 or the like can be strongly rubbed, and scratches can occur on the processed surface of the object to be polished 8.

[0074] The polishing layer 4 is formed by mixing an isocyanate group-containing compound and a curing agent (chain extender) mixed with hollow microspheres described later, obtaining a mixed liquid, injection molding the mixed liquid and curing it, obtaining a foam, and slicing the foam.

[0075] In the polishing pad 3 of the present application, the hollow microspheres 4A are used so that the bubbles are enclosed inside the polyurethane resin molded body. The hollow microspheres refer to microspheres having voids. The shape of the hollow microspheres 4A includes a spherical shape, an elliptical shape, and shapes close to them. As examples, there can be given inflated microspheres and microspheres obtained by heating and expanding unexpanded heat-expandable microspheres.

[0076] By adjusting the composition of the polishing layer 4, the number and size of the hollow microspheres 4A, and the like, the physical properties such as the Shore D hardness of the polishing layer 4 can be set to a desired numerical range.

[0077] <Buffer layer>

[0078] (Composition)

[0079] The polishing pad 3 of the present application has a buffer layer 6. For the buffer layer 6, it is desirable to make the abutment of the polishing layer 4 and the object to be polished 8 more uniform. As the material of the buffer layer 6, there can be mentioned resins; impregnated materials obtained by impregnating the resins in a base material; flexible materials such as synthetic resins, rubbers, and the like; and sponge materials using the resins. As the resins, there can be mentioned, for example, resins such as polyurethane, polyethylene, polybutadiene, silicone, and the like; rubbers such as natural rubber, nitrile rubber, polyurethane rubber, and the like.

[0080] The buffer layer 6 can employ a foamed body having a bubble structure or the like. As the bubble structure, in addition to a bubble structure in which voids are formed in the inside of a nonwoven fabric or the like, a suede-like bubble structure having a tear-shaped bubble formed by a wet film forming method, a sponge-like bubble structure in which fine bubbles are formed can be preferably used.

[0081] <Adhesive layer>

[0082] The adhesive layer 7 is a layer for adhering the buffer layer 6 and the polishing layer 4, and is usually composed of a double-sided adhesive tape or an adhesive. The double-sided adhesive tape or the adhesive can use a material (for example, an adhesive sheet) known in the art.

[0083] The polishing layer 4 and the buffer layer 6 are adhered by the adhesive layer 7. The adhesive layer 7 can be formed of, for example, at least one adhesive selected from the group consisting of acrylic, epoxy, and urethane. For example, when an acrylic adhesive is used, the thickness can be set to 0.1 mm.

[0084] <Tan delta>

[0085] The polishing pad 3 of the present application is characterized in that, with respect to the ratio of the storage elastic modulus E' to the loss elastic modulus E" (tan δ) when a dynamic viscoelasticity test is performed on the entire polishing pad 3 using dispersion (25°C) in a bending mode, the ratio of the maximum value of tan δ (tan δ max100-1000 ) at 0.1 to 10,000 rad / s to the minimum value of tan δ (tan δ max1-10 ) is 1 to 1.3.

[0086] Further, it is preferable that the ratio of the maximum value of tan δ (tan δ max0.1-10000 ) to the minimum value of tan δ (tan δ min0.1-10000 ) at 0.1 to 10,000 rad / s is 1 to 1.3.

[0087] Further, preferably, the difference between the maximum value and the minimum value of tan δ in the range of 0.1 to 10,000 rad / s (maximum value (tan δ max0.1-10000 ) - minimum value (tan δ min0.1-10000 )) is 0 to 0.1.

[0088] Tan δ is the ratio of E" (loss elastic modulus) to E' (storage elastic modulus) (E" / E'). According to the value of tan δ, the correlation between the end collapse and tan δ was investigated with an eye on the influence on the dishing phenomenon, and as a result, it was ascertained that if tan δ obtained by testing the entire polishing pad 3 in the bending mode is in the above range, the end collapse can be suppressed.

[0089] That is, the ratio of the maximum value of tan δ in the range of 100 to 1,000 rad / s to the maximum value of tan δ in the range of 1 to 10 rad / s is 0.75 to 1.30 means that even in a wide range of frequencies, tan δ does not differ greatly.

[0090] The frequency is discussed. Figure 5 The frequency is discussed. Figure 5 is a view of the state of polishing from above. The arrow indicates the direction of rotation. The object to be polished 8 is disposed in the clasp 16A (or the holding platform 16) and on the polishing layer 4 of the polishing pad 3. In this example, the polishing layer 4 rotates counterclockwise as indicated by the arrow. Also, the object to be polished disposed in the clasp 16A rotates clockwise, and polishing is performed.

[0091] With the conventional polishing frequency, the angular frequency is calculated from the contact time calculated from the diameters and speeds of the object to be polished and the object polished, and the usual frequency of polishing is about 1 to 10 rad / s of angular frequency. This is calculated based on a model in which the polishing pad 3 deforms at a constant speed from the time when it starts to contact the object to be polished 8 until it passes through, and after the object to be polished 8 passes through, it releases at a constant speed and the deformation recovers.

[0092] However, in the course of implementing the present application, it was investigated, and as a result, it was ascertained that actually the object to be polished 8 is in a state of being held by the clasp 16A. Therefore, some portions of the polishing layer 4 first contact the clasp 16A due to rotation, then contact the object to be polished 8, then contact the clasp 16A again, and finally release. If this situation is taken into account for calculation, it is considered that the frequency is about 100 to 1,000 rad / s.

[0093] Considering the above situation, it can be seen that the preferred frequency is one that does not differ not only in the range of 1 to 10 rad / s, but also in a wider range of 100 to 1000 rad / s. In other words, it is preferable that the ratio of the maximum value of tanδ in the range of 1 to 10 rad / s to the maximum value in the range of 100 to 1000 rad / s varies little. In fact, it can be seen that if the grinding pad 3 has a ratio of the maximum value of tanδ in the range of 100 to 1000 rad / s to the maximum value of tanδ in the range of 1 to 10 rad / s of 0.75 to 1.30, then the end edge collapse is small.

[0094] When calculating frequencies of 100–1000 rad / s, Figure 5 Near the symbol E (near the edge), the rotation direction of the abrasive pad and the rotation direction of the object being abraded are substantially opposite; therefore, the relative velocity is the difference between the individual velocities. Conversely, near C (near the center), the rotation direction of the abrasive pad and the rotation direction of the object being abraded are substantially the same; therefore, the relative velocity is the sum of the individual velocities. It should be noted that near M (near the center), the angular velocity of the object being abraded is 0; therefore, the relative velocity is the same as the rotational velocity of the abrasive pad. These descriptions, of course, apply to calculations at frequencies of 100–1000 rad / s.

[0095] (Dynamic viscoelasticity test)

[0096] Regarding tanδ, the entire abrasive pad is measured using a dynamic viscoelasticity test (DMA) in bending mode. The dynamic viscoelasticity test (DMA) is a method in which deformation or stress that changes over time (vibration) is applied to the sample, and the resulting stress or deformation is measured to determine the mechanical properties of the sample. A schematic diagram illustrating the dynamic viscoelasticity test of the entire abrasive pad 3 of the present invention is shown below. Figure 6 .picture Figure 6 The abrasive pad 3 is clamped in place using a clamp 12 with the upper surface designated as the abrasive layer 4 and the lower surface as the buffer layer 6. The stress is measured when a small-amplitude sinusoidal waveform is applied and deformed. In other words, in this invention, a dynamic viscoelasticity test is performed on the entire abrasive pad 3. This "entirely" refers not only to the abrasive layer 4, but also not only to the buffer layer 6. It means that the abrasive layer 4 and the buffer layer 6 are bonded together using an adhesive layer. It should be noted that... Figure 6 The adhesive layer is not shown in the diagram.

[0097] The following section describes the overall measurement of tanδ for the abrasive pad 3.

[0098] tan δ is the ratio of E" (loss elastic modulus) to E' (storage elastic modulus) (E" / E'), and these values are affected not only by the polishing layer 4 but also by the buffer layer 6. In the past, in this technical field, tan δ was measured only for the material of the polishing layer. However, in fact, tan δ is greatly affected not only by the polishing layer but also by the material of the buffer layer, and it is known that the size of the end edge collapse varies depending on the buffer layer. The measurement results of tan δ of the entire polishing pad of Examples 1 and 2 described later are shown in Figure 8 and Figure 10 , and the measurement results of tan δ of only the polishing layer B used in Examples 1 and 2 are shown in Figure 12 . From Figure 8 , Figure 10 and Figure 12 , it is known that the behavior of tan δ at the time of dispersion sometimes greatly changes between the case where only the polishing layer is present and the case where the polishing pad in which the polishing layer and the buffer layer are integrated is present. Therefore, in the present application, tan δ is measured for the entire polishing pad including not only the polishing layer but also the buffer layer.

[0099] In addition, generally, dynamic viscoelasticity tests have measurement in a bending mode and measurement in a tensile compression mode, and in the present application, the test is performed in the measurement in the bending mode. With respect to actual polishing, each layer of the polishing pad 3 is pressed against the object to be polished 8 in the vertical direction. Therefore, it is known that the measurement should be performed in the measurement mode (bending mode) in the same direction as the pressing direction.

[0100] The ratio of the maximum value of tan δ at a frequency of 100 to 1000 rad / s to the maximum value of tan δ at 1 to 10 rad / s is 0.75 to 1.30, which means that the storage elastic modulus E' and the loss elastic modulus E" do not greatly differ between the range of 1 to 10 rad / s and the range of 100 to 1000 rad / s. Such a polishing pad can suppress the end edge collapse.

[0101] Further, a polishing pad in which the maximum value / minimum value of tan δ at 0.1 to 10000 rad / s is 1 to 1.3 means that tan δ does not greatly vary in a wide frequency range, and the difference (maximum value - minimum value) of the maximum value and the minimum value of tan δ at 0.1 to 10000 rad / s is 0 to 0.1, which also means that tan δ does not greatly vary in a wide frequency range.

[0102] It should be noted that the value of tan δ can be adjusted by, for example, changing the material of the polishing layer 4 and the buffer layer 6, changing the size, the number, and the density of the bubbles included in the polishing layer 4 and the buffer layer 6.

[0103] <Storage Elastic Modulus Ratio E' 1000 / E' 10 >

[0104] Regarding the abrasive pad 3 of the present invention, the storage elastic modulus E' when the abrasive pad 3 as a whole is subjected to a dynamic viscoelastic test using dispersion (25°C) in bending mode is obtained by using the value of E' at 1000 rad / s (E' 1000 The value of E' at 10 rad / s (E') 10 The ratio of (E') 1000 / E' 10 A value of 1 to 2 improves step elimination performance. For the abrasive layer and buffer layer commonly used in abrasive pads, the value of E' increases monotonically with increasing frequency; therefore, E'... 1000 / E' 10 Materials with a value less than 1 are special materials; their physical properties and grinding performance are generally unsuitable for use as grinding pads, and are therefore undesirable. On the other hand, if E' 1000 / E' 10 If the value exceeds 2, the step-eliminating property decreases. E' 1000 / E' 10 The preferred range is 1.4 or higher and 1.9 or lower, more preferably 1.5 or higher and 1.85 or lower. The energy storage modulus refers to the component of energy stored within an object due to external forces and deformation.

[0105] In the determination of the energy storage elastic modulus E', the value of E' at 1000 rad / s is used as a ratio to the value of E' at 10 rad / s. This is to allow for comparison of the energy storage elastic modulus over a wider frequency range. The rationale for choosing such a wide frequency range is the same as in the case of tanδ. In fact, the variation of the energy storage elastic modulus E' over such a wide frequency range is relatively small (E' 10 With E' 1000 In the abrasive pad of the present invention with a ratio of 1 to 2), the value of E' does not change significantly due to the position of the workpiece being abraded. Therefore, it can be seen that not only is the planarization performance excellent, but the step elimination performance is also excellent for workpieces with steps.

[0106] The energy storage elastic modulus E' was obtained by dynamic viscoelasticity test (DMA) on the entire abrasive pad in bending mode. The measurement method is the same as that already described, so it is omitted.

[0107] The value of the storage elastic modulus E' is affected not only by the polishing layer 4 but also by the cushion layer 6, as is the case with tan δ. In the past, the measurement of the storage elastic modulus E' has been performed only with respect to the material of the polishing layer in this technical field. However, in fact, the storage elastic modulus E' is greatly affected not only by the polishing layer but also by the material of the cushion layer, and it is known that the step-removing performance greatly changes depending on the cushion layer. It is known from the measurement results of the storage elastic modulus E' of the entire polishing pad in Examples 5 and 6 described later and the measurement results of Comparative Example 1 in which different cushion layers were used even for the same polishing layer that the behavior at the time of dispersion of the storage elastic modulus E' greatly changes depending on the combination. Therefore, in the present application, the measurement of the storage elastic modulus E' is performed with respect to the entire polishing pad including not only the polishing layer but also the cushion layer.

[0108] It should be noted that the value of the storage elastic modulus E' can be adjusted by, for example, changing the materials of the polishing layer 4 and the cushion layer 6, adjusting the hardness, density, compressibility, etc. of the polishing layer 4 and the cushion layer 6, changing the size, number, and density of the air bubbles contained in the polishing layer 4 and the cushion layer 6, etc. However, it is important that the ratio of E' 10 to E' 1000 is 1 to 2. If the ratio of E' 10 to E' 1000 is 1 to 2, it means that the storage elastic modulus E' does not greatly change in a wide frequency range.

[0109] The step-removing performance refers to the performance of making the steps of a pattern wafer having steps (unevenness) smaller with polishing. A schematic view of an experiment for measuring the step-removing performance is shown in Figure 7 . In the case where the steps in the object to be polished are 3500 A, the step-removing state when a polishing pad having a high step-removing performance (dotted line) is used and the step-removing state when a polishing pad having a relatively low step-removing performance (solid line) is used are shown. At the time of (a) in Figure 7 , there is no difference in the steps, but as the polishing proceeds, at the time when the polishing amount is 2000 A, the polishing pad having a good step-removing performance (dotted line) shows smaller steps than the polishing pad having a relatively low step-removing performance (solid line) ((b)), and the polishing pad having a high step-removing performance can make the steps disappear even with a relatively small polishing amount ((c)). It can be said that the step-removing performance of the polishing pad shown by the dotted line is relatively high compared with the polishing pad shown by the solid line.

[0110] <Manufacturing method of polishing pad>

[0111] A manufacturing method of the polishing pad 3 of the present application will be described.

[0112] <Material of polishing layer>

[0113] As the material of the polishing layer 4, there is no particular limitation, and, for example, as a main component, polyurethane resin, polyurea resin, and polyurethane polyurea resin are preferable, and polyurethane resin is more preferable. As a specific material of the main component, for example, a material obtained by reacting a polyisocyanate compound containing a urethane bond and a curing agent can be given.

[0114] Hereinafter, the manufacturing method of the material of the polishing layer 4 will be described using an example in which an isocyanate compound containing a urethane bond, a polyol compound, and a curing agent are used.

[0115] As the manufacturing method of the polishing layer 4 using a polyisocyanate compound containing a urethane bond and a curing agent, for example, a manufacturing method including a material preparation step of preparing at least a polyisocyanate compound containing a urethane bond, an additive, and a curing agent; a mixing step of mixing at least the polyisocyanate compound containing a urethane bond, the additive, and the curing agent to obtain a mixed solution for molding a molded body; and a curing step of molding the polishing layer 4 from the mixed solution for molding a molded body can be given.

[0116] Hereinafter, the material preparation step, the mixing step, and the molding step will be described separately.

[0117] <Material Preparation Step>

[0118] In order to manufacture the polishing layer 4 of the present application, as a raw material of a polyurethane resin molded body (cured resin), a polyisocyanate compound containing a urethane bond and a curing agent are prepared. Here, the polyisocyanate compound containing a urethane bond is a urethane prepolymer used for forming a polyurethane resin molded body. In the case where the polishing layer 4 is a polyurea resin molded body or a polyurethane polyurea resin molded body, a prepolymer corresponding thereto is used.

[0119] Hereinafter, each component will be described.

[0120] (Polyisocyanate Compound Containing a Urethane Bond)

[0121] The polyisocyanate compound containing a urethane bond (urethane prepolymer) is a compound obtained by reacting a polyisocyanate compound and a polyol compound under conditions generally used, and contains a urethane bond and an isocyanate group in the molecule. In addition, other components can be contained in the polyisocyanate compound containing a urethane bond within a range not impairing the effects of the present application.

[0122] As the polyisocyanate compound containing a urethane bond, a commercially available product can be used, or a product synthesized by reacting a polyisocyanate compound and a polyol compound can be used. The reaction is not particularly limited, and an addition polymerization reaction is performed using a publicly known method and conditions in the production of a polyurethane resin. For example, the production can be performed by a method in which a polyisocyanate compound warmed to 50°C is added to a polyol compound warmed to 40°C while stirring is performed under a nitrogen atmosphere, the temperature is increased to 80°C after 30 minutes, and then the reaction is performed at 80°C for 60 minutes.

[0123] It should be noted that the NCO equivalent of the polyisocyanate containing a urethane bond is preferably around 300 to 600. Therefore, in the case where the polyisocyanate containing a urethane bond is a commercially available product, it is preferable that the NCO equivalent satisfy the above range, and in the case where the production is performed by synthesis, it is preferable that the raw materials described below be used in an appropriate ratio to achieve the NCO equivalent in the above range.

[0124] (Polyisocyanate compound)

[0125] In the present specification, the polyisocyanate compound refers to a compound having two or more isocyanate groups in a molecule.

[0126] As the polyisocyanate compound, it is sufficient that two or more isocyanate groups are present in a molecule, and there is no particular limitation. For example, as a diisocyanate compound having two isocyanate groups in a molecule, m-phenylene diisocyanate, p-phenylene diisocyanate, 2,6-toluene diisocyanate (2,6-TDI), 2,4-toluene diisocyanate (2,4-TDI), naphthalene-1,4-diisocyanate, diphenylmethane-4,4'-diisocyanate (MDI), 4,4'-methylene-bis(cyclohexyl isocyanate) (hydrogenated MDI), 3,3'-dimethoxy-4,4'-diphenyl diisocyanate, 3,3'-dimethyldiphenylmethane-4,4'-diisocyanate, xylene-1,4-diisocyanate, 4,4'-diphenylpropane diisocyanate, trimethylene diisocyanate, hexamethylene diisocyanate, propylene-1,2-diisocyanate, butylene-1,2-diisocyanate, cyclohexylene-1,2-diisocyanate, cyclohexylene-1,4-diisocyanate, p-phenylene diisothiocyanate, xylene-1,4-diisothiocyanate, ethylene diisothiocyanate, and the like can be given. These polyisocyanate compounds can be used alone, or a plurality of polyisocyanate compounds can be used in combination.

[0127] It should be noted that, as the polyisocyanate compound, it is preferable to contain 2,4-TDI and / or 2,6-TDI.

[0128] (Polyol compound as a raw material of a prepolymer)

[0129] In the present specification, a polyol compound refers to a compound having two or more hydroxyl groups (OH) in a molecule.

[0130] As the polyol compound used for synthesizing the polyisocyanate compound containing a urethane bond as a prepolymer, for example, a diol compound such as ethylene glycol, diethylene glycol (DEG), butanediol, and the like; a triol compound and the like; a polyether polyol compound such as poly(tetramethylene oxide) glycol (or polytetramethylene ether glycol) (PTMG), and the like can be given. Among them, DEG and PTMG are preferable.

[0131] The number average molecular weight (Mn) of PTMG is not particularly limited, and for example, can be 500 to 2000. Here, the number average molecular weight can be measured using a gel permeation chromatograph (GPC). Note that in the case where the number average molecular weight of the polyol compound is measured from the polyurethane resin, each component can be decomposed by a conventional method such as amine decomposition, and then estimated by GPC.

[0132] The above polyol compound can be used alone, or a plurality of polyol compounds can be used in combination.

[0133] (Additives)

[0134] As described above, as the material of the polishing layer 4, an additive such as an oxidizing agent can be added as needed.

[0135] (Curing agent)

[0136] In the production method of the polishing layer 4 of the present application, a curing agent (also referred to as a chain extender) is mixed with the polyisocyanate compound containing a urethane bond and the like in the mixing step. By adding the curing agent, in the subsequent molding body molding step, the main chain end of the polyisocyanate compound containing a urethane bond is bonded to the curing agent to form a polymer chain, and curing is performed.

[0137] As the curing agent, for example, ethylenediamine, propylenediamine, hexamethylenediamine, isophorone diamine, dicyclohexylmethane-4,4'-diamine, 3,3'-dichloro-4,4'-diaminodiphenylmethane (MOCA), 4-methyl-2,6-bis(methylthio)-l,3-benzenediamine, 2-methyl-4,6-bis(methylthio)-l,3-benzenediamine, 2,2-bis(3-amino-4-hydroxyphenyl)propane, 2,2-bis[3-(isopropylamino)-4-hydroxyphenyl]propane, 2,2-bis[3-(l-methylpropylamino)-4-hydroxyphenyl]propane, 2,2-bis[3-(l-methylpentylamino)-4-hydroxyphenyl]propane, 2,2-bis(3,5-diamino-4-hydroxyphenyl)propane, 2,6-diamino-4-methylphenol, trimethylenediamine bis-4-aminobenzoate, and polytetramethylene oxide bis-p-aminobenzoate, and the like polyamine compounds; ethylene glycol, propylene glycol, diethylene glycol, trimethylene glycol, tetraethylene glycol, triethylene glycol, dipropylene glycol, 1,4-butanediol, 1,3-butanediol, 2,3-butanediol, 1,2-butanediol, 3-methyl-l,2-butanediol, 1,2-pentanediol, 1,4-pentanediol, 2,4-pentanediol, 2,3-dimethyltrimethylene glycol, tetramethylene glycol, 3-methyl-4,3-pentanediol, 3-methyl-4,5-pentanediol, 2,2,4-trimethyl-l,3-pentanediol, 1,6-hexanediol, 1,5-hexanediol, 1,4-hexanediol, 2,5-hexanediol, 1,4-cyclohexanedimethanol, neopentyl glycol, glycerol, trimethylolpropane, trimethylolethane, trimethylolmethane, poly(tetramethylene oxide) glycol, polyethylene glycol, and polypropylene glycol, and the like polyol compounds. In addition, the polyamine compound can have a hydroxyl group, and as such amine-based compounds, for example, 2-hydroxyethyl ethylenediamine, 2-hydroxyethyl propylenediamine, di-2-hydroxyethyl ethylenediamine, di-2-hydroxyethyl propylenediamine, 2-hydroxypropyl ethylenediamine, di-2-hydroxypropyl ethylenediamine, and the like. As the polyamine compound, a diamine compound is preferable, and for example, 3,3'-dichloro-4,4'-diaminodiphenylmethane (methylene bis-ortho-chloroaniline) (hereinafter, referred to as MOCA) is more preferable.

[0138] The abrasive layer 4 can be formed of a material having a hollow microsphere 4A with a shell and a hollow interior. As the material of the hollow microsphere 4A, a commercially available product or a product synthesized by a conventional method can be used. The material of the shell of the hollow microsphere 4A is not particularly limited, and for example, polyvinyl alcohol, polyvinylpyrrolidone, poly(meth)acrylic acid, polyacrylamide, polyethylene glycol, polyhydroxy ether acrylate, a maleic acid copolymer, polyethylene oxide, polyurethane, poly(meth)acrylonitrile, polyvinylidene chloride, polyvinyl chloride, silicone-based resins, and a copolymer obtained by combining two or more monomers that constitute the above resins (for example, acrylonitrile-vinylidene chloride copolymer) can be mentioned. In addition, the hollow microspheres as commercially available products are not limited to the following products, and for example, Expancel series (trade name, manufactured by Akzonobel), Matsumoto Microsphere (trade name, manufactured by Matsumoto Oil and Fat Co., Ltd.), and the like can be mentioned.

[0139] The gas contained in the hollow microsphere 4A is not particularly limited, and for example, a hydrocarbon, specifically, isobutane, and the like can be mentioned.

[0140] The shape of the hollow microsphere 4A is not particularly limited, and for example, spherical and substantially spherical shapes can be mentioned. The average particle diameter of the hollow microsphere 4A is not particularly limited, and is preferably 5 to 200 μm, more preferably 5 to 80 μm, further preferably 5 to 50 μm, and particularly preferably 5 to 35 μm. Note that the average particle diameter can be measured by a laser diffraction particle size distribution measuring device (for example, Mastersizer-2000 manufactured by Spectris).

[0141] The material of the hollow microsphere 4A is preferably added in an amount of 0.1 to 10 parts by mass, more preferably 1 to 5 parts by mass, and further preferably 1 to 4 parts by mass, relative to 100 parts by mass of the urethane prepolymer.

[0142] In addition, in addition to the above components, a foaming agent used in the past can be used in combination with the hollow microsphere 4A without impairing the effects of the present application, and a non-reactive gas can be blown into the mixture in the following mixing step, relative to the respective components. As the foaming agent, in addition to water, a foaming agent in which a hydrocarbon having 5 or 6 carbon atoms is the main component can be mentioned. As the hydrocarbon, for example, straight-chain hydrocarbons such as n-pentane and n-hexane, alicyclic hydrocarbons such as cyclopentane and cyclohexane can be mentioned.

[0143] < Mixing Step >

[0144] In the mixing step, the urethane-bond-containing polyisocyanate compound (urethane prepolymer) obtained in the preparation step, the additive, and the curing agent are supplied to a mixing machine and mixed by stirring. The mixing step is performed in a state in which the temperature is raised to a temperature at which the flowability of each component is ensured.

[0145] <Shaping Step>

[0146] In the molding body molding step, the molding body molding solution prepared in the mixing step is poured into a quadrangular mold box preheated to 30 to 100°C, and is once cured, and then is heated at 100 to 150°C for 10 minutes to 5 hours or so to be twice cured, whereby the cured polyurethane resin (polyurethane resin molding body) is molded. At this time, the urethane prepolymer and the curing agent react to form the polyurethane resin, and the solution is cured.

[0147] If the viscosity of the urethane prepolymer is too high, the flowability is poor, and it is difficult to mix the components uniformly. If the temperature is raised to reduce the viscosity, the service life is shortened, and instead, a foamed body having a mixed color is formed, and the size of the hollow fine spheres 4A is deviated. On the contrary, if the viscosity is too low, the bubbles move in the solution, and it is difficult to form the hollow fine spheres 4A dispersed substantially uniformly in the obtained foamed body. Therefore, for the prepolymer, the viscosity at 50 to 80°C is preferably set to a range of 500 to 4000 mPa-s. For example, the viscosity can be set by changing the molecular weight (polymerization degree) of the prepolymer. The prepolymer is heated to 50 to 80°C or so to be in a flowable state.

[0148] In the molding step, the injected solution is allowed to react in the mold box as needed to form a foamed body. At this time, the prepolymer is crosslinked and cured by the reaction of the prepolymer and the curing agent.

[0149] After the molding body is obtained, it is cut into a sheet shape to form a plurality of abrasive layers 4. A general sheet cutter can be used for the cutting. The lower portion of the abrasive layer 4 is held, and the upper portion is cut into a predetermined thickness in order. The thickness of the cut sheet is set to a range of, for example, 1.3 to 2.5 mm. In a foamed body molded in a mold box having a thickness of 50 mm, for example, about 10 mm portions of the upper and lower portions of the foamed body are not used due to scratches or the like, and 10 to 25 abrasive layers 4 are formed from about 30 mm portions of the central portion. A foamed body in which the hollow fine spheres 4A are substantially uniformly formed inside is obtained in the curing molding step.

[0150] The ground surface of the obtained polishing layer 4 is subjected to groove processing as needed. The polishing surface is subjected to cutting processing or the like using a desired tool, whereby grooves having arbitrary pitch, width, and depth can be formed. As the slurry holding grooves, for example, circular grooves formed in a concentric circular shape can be given; as the slurry discharge grooves, for example, straight grooves formed in a lattice shape, straight grooves formed radially from the center of the polishing layer, and the like can be given.

[0151] After that, a double-sided tape is attached to the surface of the polishing layer 4 opposite to the polishing surface, with respect to the polishing layer 4 thus obtained. The double-sided tape is not particularly limited, and can be arbitrarily selected from among double-sided tapes publicly known in the technical field.

[0152] <Manufacturing method of the buffer layer 6>

[0153] As the material of the buffer layer 6, as described above, an impregnated material obtained by impregnating a resin solution of polyurethane or the like into a base material such as a nonwoven fabric, a woven fabric, or the like formed of polyethylene, polyester, or the like; a suede material using a resin material of polyurethane or the like; and a sponge material using a material of polyurethane or the like can be given. Note that the buffer layer 6 can be manufactured according to the manufacturing method described below, or a commercially available product can be used.

[0154] <Case of the impregnated material, the suede material>

[0155] In the forming step of the buffer layer 6, the buffer layer 6 is formed by wet film formation. That is, the buffer layer 6 is formed by the following steps: a preparation step of preparing a resin solution in which a polyurethane resin is dissolved substantially uniformly in an organic solvent, a coagulation regeneration step of spreading the resin solution prepared in the preparation step into a sheet shape and removing the organic solvent from the resin solution in an aqueous coagulation liquid to coagulate and regenerate the polyurethane body, and a washing and drying step of washing and drying the polyurethane body coagulated and regenerated in the coagulation regeneration step to form the buffer layer 6, which will be described below in the order of the steps.

[0156] (Preparation step)

[0157] In the preparation step, a polyurethane resin and an additive added as needed are dissolved in an organic solvent to prepare a resin solution. The resin solution is prepared by dissolving the polyurethane resin and the additive substantially uniformly in a water-miscible organic solvent in which the polyurethane resin is soluble, removing coagulated pieces or the like by filtration, and degassing under vacuum, whereby the resin solution is prepared. As the organic solvent, N,N-dimethylformamide (hereinafter referred to as DMF), dimethylacetamide (hereinafter referred to as DMAc), or the like can be used. For example, DMF is used as the organic solvent. The polyurethane resin can be selected from among a polyester-based resin, a polyether-based resin, a polycarbonate-based resin, and the like.

[0158] As an additive to be added as needed, a pigment such as carbon black, a hydrophilic active agent to promote foaming, and a hydrophobic active agent to stabilize the coagulation regeneration of the polyurethane resin, and the like can be used. By changing the kind and the amount of the additive to be added, the size or the amount (number) of the tear-shaped bubbles formed inside the buffer layer 6 can be controlled. The tan δ and the storage elastic modulus E' of the polishing pad 3 are also affected by the properties of the buffer layer 6, and therefore, the tan δ and the storage elastic modulus E' of the polishing pad 3 are adjusted by appropriately setting the selection of the material, the selection of the organic solvent, the mixing ratio of the resin and the organic solvent, the size and the amount of the tear-shaped bubbles, and the thickness of the buffer layer 6. For example, with respect to 100 parts of the resin solution, the polyurethane resin is set to a range of 45 to 62 parts, and the DMF is set to a range of 8 to 32 parts.

[0159] (Coagulation Regeneration Process)

[0160] In the coagulation regeneration process, the resin solution prepared in the preparation process is continuously applied to a film-forming substrate (extended to a sheet shape), and immersed in an aqueous coagulation liquid, thereby coagulating and regenerating the polyurethane resin in a sheet shape. The resin solution prepared in the preparation process is applied to a belt-shaped film-forming substrate by a coater such as a doctor blade coater at ordinary temperature. At this time, the application thickness (application amount) of the resin solution is adjusted by adjusting the clearance between the coater and the film-forming substrate. In this example, the application amount is adjusted so that the thickness of the buffer layer 6 is in a range of 0.5 to 2.0 mm. As the film-forming substrate, a flexible film, a nonwoven fabric, a woven fabric, or the like can be used. In the case of using a nonwoven fabric or a woven fabric, in order to suppress the penetration into the inside of the film-forming substrate at the time of application of the resin solution, a pretreatment (sealing) of immersion in water or a DMF aqueous solution (a mixed solution of DMF and water), or the like is performed in advance.

[0161] The film-forming substrate to which the resin solution is applied is immersed in an aqueous coagulation liquid in which water, which is a poor solvent with respect to the polyurethane resin, is the main component. In the aqueous coagulation liquid, first, micro-pores constituting a surface layer are formed on the surface of the applied resin solution in a range of several μm in thickness. Subsequently, replacement of the DMF with the aqueous coagulation liquid is performed in the resin solution, thereby coagulating and regenerating the polyurethane body in a sheet shape on one side of the film-forming substrate. The DMF is removed from the resin solution, and the replacement of the DMF with the aqueous coagulation liquid is performed, thereby forming a large number of tear-shaped bubbles in the polyurethane body, and forming a three-dimensional network of the tear-shaped bubbles. At this time, since the PET film of the film-forming substrate does not allow the penetration of water, desolvation occurs on the surface side (surface layer side) of the resin solution, and tear-shaped bubbles having a larger pore diameter on the film-forming substrate side than on the surface side are formed. That is, a large number of bubbles having a cross section of a substantially triangular shape with a roundness along the thickness direction of the polyurethane body are formed in a substantially uniform dispersed state inside the polyurethane body.

[0162] (Cleaning and Drying Process)

[0163] In the cleaning and drying step, the strip-shaped (long strip-shaped) polyurethane body, which is coagulation-regenerated in the coagulation-regeneration step, is cleaned and then dried to form the cushion layer 6. That is, the polyurethane body is cleaned in a cleaning liquid such as water to remove DMF remaining in the polyurethane body. After the cleaning, the polyurethane body is dried using a drum dryer. The drum dryer has a drum having a heat source inside. The polyurethane body is dried while passing along the circumferential surface of the drum to form the cushion layer 6.

[0164] < Bonding Step >

[0165] In the bonding step, the formed abrasive layer 4 and the cushion layer 6 are bonded (joined) by the adhesive layer 7. The adhesive layer 7 is formed to have a thickness of 0.1 mm using, for example, an acrylic adhesive. That is, the acrylic adhesive is applied to the surface of the abrasive layer 4 on the side opposite to the abrasive surface to have a substantially uniform thickness. The surface of the abrasive layer 4 on the side opposite to the abrasive surface and the surface (the surface on which the surface layer is formed) of the cushion layer 6 are pressure-bonded by the applied adhesive to bond the abrasive layer 4 and the cushion layer 6 by the adhesive layer 7. Then, after being cut into a desired shape such as a circular shape, the abrasive pad 3 is completed after being subjected to an inspection for checking the presence or absence of dirt, foreign matter, or the like.

[0166] Examples

[0167] Hereinafter, the present application will be described in further detail using examples, but the present application is not limited to these examples.

[0168] In each of the examples and comparative examples, "parts" means "mass parts" unless otherwise specified.

[0169] In addition, the NCO equivalent is a value indicating the molecular weight of the prepolymer (PP) per one NCO group, which is calculated by "(mass (parts) of the polyisocyanate compound + mass (parts) of the polyol compound) / [(functional group number per one molecule of the polyisocyanate compound x mass (parts) of the polyisocyanate compound / molecular weight of the polyisocyanate compound) - (functional group number per one molecule of the polyol compound x mass (parts) of the polyol compound / molecular weight of the polyol compound)]".

[0170] (About the Abrasive Layer A)

[0171] To 100 parts of an isocyanate group-terminated urethane prepolymer having an NCO equivalent of 460 obtained by reacting 2,4-toluene diisocyanate (TDI), poly(tetramethylene oxide) glycol (PTMG), and diethylene glycol (DEG), 2.6 parts of unexpanded hollow microspheres having a shell composed of acrylonitrile-vinylidene chloride copolymer and containing isobutane gas in the shell were added, and mixed to obtain a mixed solution. The obtained mixed solution was charged into a first liquid container and kept warm. Next, a curing agent was prepared separately from the first liquid, and as the curing agent, 25.5 parts of MOCA and 8.5 parts of polypropylene glycol (PPG) were added and mixed, and kept warm in a second liquid container. The liquids in the first liquid container and the second liquid container were each injected into a mixer having two injection ports, and injected from the respective injection ports in a manner such that the R value, which indicates the equivalent ratio of the amino group and the hydroxyl group present in the curing agent with respect to the terminal isocyanate group in the prepolymer, was 0.90. While the two liquids thus injected were mixed and stirred, they were injected into a mold of a molding machine that had been preheated, and then the mold was closed and heated for 30 minutes to effect primary curing. After the molded product obtained by primary curing was demolded, secondary curing was performed in an oven at 130°C for 2 hours to obtain a polyurethane molded product. After the obtained polyurethane molded product was cooled to 25°C, heating was performed again in an oven at 120°C for 5 hours, and then the product was cut to a thickness of 1.3 mm to obtain a polishing layer A.

[0172] (Concerning Polishing Layer B)

[0173] The mixed solution of the first liquid used in the polishing layer A was a mixed solution of 100 parts of an isocyanate group-terminated urethane prepolymer having an NCO equivalent of 455 and 2.7 parts of unexpanded hollow microspheres, and the second liquid used in the polishing layer A was only 25.8 parts of MOCA, and otherwise, the polishing layer B was produced by the same method as the polishing layer A.

[0174] (Concerning Polishing Layer C)

[0175] To the first liquid used in the polishing layer A, 2 parts of 4,4'-methylene-bis(cyclohexyl isocyanate) (hydrogenated MDI) were further mixed, the amount of unexpanded hollow microspheres was 2.85 parts, and the second liquid used in the polishing layer A was only 28 parts of MOCA, and otherwise, the polishing layer C was produced by the same method as the polishing layer A.

[0176] (Concerning Polishing Layer D as a Polishing Layer)

[0177] A product having a trade name of "IC1000" manufactured by NITTA HAAS Co., Ltd. was used as the polishing layer D.

[0178] (Concerning Buffer Layers (I) to (V))

[0179] As the polyurethane resin, a polyester MDI (diphenylmethane diisocyanate) polyurethane resin was used in the production of the cushion layer (I). A polyurethane resin solution was prepared by adding 25 parts of a solvent DMF, 40 parts of a DMF dispersion liquid containing carbon black at 20% as a pigment, and 2 parts of a hydrophobic surfactant as a film formation stabilizer to 100 parts of a 30% polyurethane resin solution, and mixing them. The obtained resin solution was applied to a PET substrate (thickness: 0.188 mm) at a thickness of 0.7 mm, and the organic solvent was removed from the resin solution in an aqueous coagulating liquid to produce the cushion layer (I) in the form including the PET substrate.

[0180] A commercially available polyurethane sheet having fine bubbles ("Shin-Etsu Sponge 2504KMS" manufactured by Shin-Etsu Chemical Co., Ltd.) was used as the cushion layer (II).

[0181] A commercially available polyurethane sheet having fine bubbles ("PORON HH-48C" manufactured by Inoac Corporation) was used as the cushion layer (III).

[0182] A nonwoven fabric (density: 0.216 g / cm 3 ) formed of polyester fibers was impregnated in a polyurethane resin solution ("C1367" manufactured by DIC Corporation). After the impregnation, the resin solution was twisted by using a universal roll capable of applying pressure between a pair of rolls to allow the resin solution to be substantially uniformly impregnated in the nonwoven fabric. Next, the impregnated resin was coagulated and regenerated by being impregnated in a coagulating liquid formed of water at room temperature to obtain a resin-impregnated nonwoven fabric. Thereafter, the resin-impregnated nonwoven fabric was taken out of the coagulating liquid, and further, impregnated in a washing liquid formed of water to remove N,N-dimethylformamide (DMF) in the resin, and then dried. After the drying, the surface layer was removed by polishing treatment to produce the cushion layer (IV). The resin adhesion rate of the cushion layer (IV) was 55%, and the thickness was 1.00 mm.

[0183] "SUBA400" manufactured by NITTA HAAS Corporation was used as the cushion layer (V).

[0184] (Examples and Comparative Examples)

[0185] The abrasive layers A to D and the cushion layers (I) to (V) were joined by double-sided adhesive tape (a member having an adhesive layer formed of an acrylic resin on both surfaces of a PET substrate) having a thickness of 0.1 mm, and the double-sided adhesive tape was attached to the opposite side of the cushion layer and the adhesive layer to produce the abrasive pads of the examples and comparative examples. The abrasive layers and the cushion layers of the examples and comparative examples are shown in Table 1.

[0186] [Table 1]

[0187]

[0188] (Dynamic viscoelasticity measurement 1)

[0189] Based on the following conditions, the dynamic viscoelasticity measurement of the polishing pad (a member in which the polishing layer and the buffer layer are bonded by means of double-sided tape) of the examples and the comparative examples was performed. The polishing pad was used as a sample in a dry state in which the polishing pad was left in a constant-temperature and constant-humidity chamber at a temperature of 23°C (±2°C) and a relative humidity of 50% (±5%) for 40 hours, and the dynamic viscoelasticity measurement was performed in a bending mode under a normal atmospheric atmosphere (dry state). The measurement conditions of the bending mode are shown below.

[0190] Measurement conditions

[0191] Measurement device: RSA-G2 (manufactured by TA instruments)

[0192] Sample: 5 cm in length x 0.5 cm in width x 0.125 cm in thickness

[0193] Test mode: Bending mode

[0194] Frequency: about 0.01 to about 10,000 (10 -2 4 ) rad / s

[0195] Measurement temperature: 5°C, 25°C, 45°C

[0196] Deformation range: 0.10%

[0197] As described above, the measurement was performed at each temperature of 5°C, 25°C, and 45°C using frequency dispersion, the temperature-frequency conversion rule was used, the synthesis of the measurement chart was performed, and tan δ at 0.001 rad / s to 100,000 rad / s was calculated. The measurement results of each example and comparative example are shown in Table 2. In addition, the results of the entire body, Figure 8 , 10 , 13 show Example 1, Example 2, and Comparative Example 1, respectively, as a reference, and the results using the polishing layer B monomer are shown in Figure 12 .

[0198] [Table 2]

[0199]

[0200] (Polishing test results)

[0201] The polishing pads of the examples and the comparative examples were subjected to polishing under the following polishing conditions. When the polishing was performed, the polishing rate (RR) was measured for 121 turns of the diameter. The curve of the polishing rate of the entire body of the polished object of Comparative Example 1 is shown in Figure 3 , the curves of the polishing rates of the entire bodies of the polished objects of Examples 1 and 2 are shown in Figure 9 , and Figure 11 ​It should be noted that measurements were taken at 2.5 mm intervals on the inner side and at 1 mm intervals on the outer side relative to a radius of 140 mm.

[0202] (Grinding Condition 1)

[0203] Grinding machine used: F-REX300 (manufactured by Ebara Manufacturing Co., Ltd.)

[0204] Abrasive temperature: 20℃

[0205] Grinding platform speed: 70 rpm

[0206] Grinding head speed: 71 rpm

[0207] Grinding pressure: 3.5 psi

[0208] Grinding slurry: Manufactured by Cabot Microelectronics Corporation, trade name: SS25

[0209] Grinding slurry flow rate: 200ml / min

[0210] Grinding time: 60 seconds

[0211] Material to be ground: Silicon wafer with TEOS (Tetra Ethyl Ortho Silicate)

[0212] The grinding results of each grinding pad of the Examples and Comparative Examples are shown in Table 3. It should be noted that the "edge rate" of the grinding result is: the grinding rate of the edge of the object being ground (the portion 149 mm from the center) divided by the average grinding rate of the portion 100 to 140 mm from the center.

[0213] [Table 3]

[0214]

[0215] like Figure 3 , Figure 13 As shown in Tables 2 and 3, the ratio (tanδ) max100-1000 / tanδ max1-10 In Comparative Example 1, where the abrasive pad reached a rate of 1.364, the rate at the outermost edge reached 1.58, confirming edge collapse. Furthermore, in Comparative Example 2, which used different abrasive and buffer layers, the ratio (tanδ) was... max100-1000 / tanδ max1-10 The value reached 1.366, and the end collapse was also confirmed.

[0216] On the other hand, such as Figures 8-9 As shown in Tables 2 and 3, the ratio (tanδ) max100-1000 / tanδmax1-10 ) of Example 1 can be controlled to 1.18, which is 1.5 or less, and the end collapse can be suppressed. In Example 2 in which a different buffer layer was used, the ratio (tan δ max100-1000 / tan δ max1-10 ) of 0.893 or less can also suppress the end collapse as in Example 1. Note that tan δ of the polishing layer B used only in Examples 1 and 2 is shown in Figure 12 However, the behavior of tan δ differs greatly from that determined for the entire polishing pad. Figure 8 and Figure 10 In Examples 3 to 6 in which the polishing layer and the buffer layer were changed variously, by setting the ratio (tan δ max100-1000 / tan δ max1-10 ) to a prescribed range, the polishing rate at the outermost edge portion was 1.5 or less, the end collapse could be suppressed, and a good edge profile could be obtained.

[0217] (Dynamic viscoelasticity measurement 2)

[0218] The measurement was performed using frequency dispersion at each temperature of 5°C, 25°C, and 45°C under the same conditions as those shown in Dynamic viscoelasticity test 1, and the measurement chart was synthesized using the temperature-frequency conversion rule. Then, the storage elastic modulus E' was calculated at 0.001 rad / s to 100,000 rad / s. The measurement results of each example and comparative example are shown in Table 4. In addition, as for the result of the entire storage elastic modulus E' with respect to the frequency, representatively, Example 2 is shown in Figure 14 Example 4 is shown in Figure 15 and Comparative Example 2 is shown in Figure 16 .

[0219] [Table 4]

[0220]

[0221] (Step polishing amount test (step elimination performance test))

[0222] The polishing pads of the examples and comparative examples were disposed at a prescribed position of a polishing device with double-sided adhesive tape having an acrylic adhesive, and polishing processing was performed under the above polishing conditions. The recesses of 100 μm / 100 μm were measured using a step / surface roughness / fine shape measuring device (KLATenchor Co., Ltd., P-16+OF), and thus the step elimination performance was evaluated. The results are shown in Figures 17-20 . Note that the recess refers to a phenomenon in which the wiring cross section is concavely dented like a dish mainly at a wiring pattern having a wide width; and the erosion refers to a phenomenon in which both the wiring and the insulating film are shaved off mainly at a fine wiring portion, and both are phenomena of excessive polishing.

[0223] The polishing rate was adjusted so that the polishing amount was 1000 A for one polishing, and polishing was performed in stages, and the step measurement of the wafer was performed each time, for a pattern wafer having a step of about 3000 to about 3500 A. The step height of the vertical axis indicates the step.

[0224] Figure 17 As a result of performing polishing on a polished object of a wiring having a wiring width of 120 μm, Figure 18 As a result of performing polishing on a polished object of a wiring having a wiring width of 100 μm with respect to a Cu wiring width, and an insulating film having a width of 100 μm, Figure 19 As a result of performing polishing on a polished object of a wiring having a wiring width of 50 μm with respect to a Cu wiring width, and an insulating film having a width of 50 μm, Figure 20 As a result of performing polishing on a polished object of a wiring having a wiring width of 10 μm with respect to a Cu wiring width, and an insulating film having a width of 10 μm, the smaller the number, the finer the wiring.

[0225] Further, with respect to the step elimination performance of Table 4 described above, in the initial polishing stage before the polishing amount reaches 2000 A, the case where the ratio of the step elimination amount (A) to the polishing amount (A) exceeds 1 for any of the pattern wafers having a wiring width of 10 μm to 120 μm was set to be good, and was indicated by O, and the case where the ratio of the step elimination amount (A) to the polishing amount (A) was 1 or less under any wiring width was set to be bad, and was indicated by X. Note that the step elimination amount was solved by subtracting the step found at a certain polishing time from the initial step (about 3000 to about 3500 A) before polishing.

[0226] (Polishing Condition 2)

[0227] Polishing machine: F-REX300X (manufactured by Asahi Process Co., Ltd.)

[0228] Disk: A188 (manufactured by 3M Company)

[0229] Polishing agent temperature: 20°C

[0230] Polishing stage rotation speed: 90 rpm

[0231] Polishing head rotation speed: 81 rpm

[0232] Polishing pressure: 3.5 psi

[0233] Polishing slurry: CSL-9044C (a mixture of CSL-9044C stock solution: pure water = weight ratio 1:9) (manufactured by Fujimi Corporation)

[0234] Polishing slurry flow rate: 200 ml / min

[0235] Polishing time: 60 seconds

[0236] Polishing object: Cu film substrate

[0237] Pad break: 32N 10 minutes

[0238] Adjustment: in-situ 18N 16 scans, Ex-situ 32N 4 scans

[0239] Industrial applicability

[0240] The present application provides a polishing pad that can achieve improvement in end collapse and / or improvement in step-elimination performance, and thus contributes to the manufacture and sale of the polishing pad, and thus has industrial applicability.

[0241] Reference signs

[0242] 1 Polishing device

[0243] 3 Polishing pad

[0244] 4 Polishing layer

[0245] 4A Hollow microspheres

[0246] 6 Cushion layer

[0247] 7 Adhesive layer

[0248] 8 Polishing object

[0249] 8a End collapse

[0250] 9 Slurry

[0251] 10 Polishing stage

[0252] 12 Jig

[0253] 16 Holding stage

Claims

1. A polishing pad characterized by comprising: a polishing layer having a polishing surface for polishing a polishing object; and a cushion layer disposed on the opposite side of the polishing layer from the polishing surface.

2. The polishing pad according to claim 1, characterized in that The maximum value of tanδ, measured at 100–1000 rad / s, is the ratio of the storage elastic modulus E' to the loss elastic modulus E'' of the entire abrasive pad, obtained by dynamic viscoelasticity testing using the bending mode at 25°C under the following measurement conditions and analytical methods. max100-1000 The maximum value of tanδ relative to tanδ measured in the range of 1–10 rad / s. max1-10 The ratio is 0.75 to 1.

30.

3. The polishing pad according to claim 1, characterized in that 4. The polishing pad according to any one of claims 1 to 3, characterized in that 5. A polishing pad characterized by comprising: a polishing layer having a polishing surface for polishing a polishing object; and a cushion layer disposed on the opposite side of the polishing layer from the polishing surface.

6. The polishing pad according to claim 5, characterized in that 7. The polishing pad according to claim 5, characterized in that the polishing layer is formed of a polyurethane resin containing hollow microspheres.

8. The polishing pad according to claim 5, characterized in that the cushion layer is at least one selected from the group consisting of an impregnated nonwoven fabric, a sponge material, and a suede material.

9. The polishing pad according to any one of claims 5 to 8, characterized in that when a pattern wafer having a step is polished, the ratio of a step elimination amount to a polishing amount exceeds 1 in the initial polishing stage before the polishing amount reaches 2000 A for any pattern wafer having a wiring width of 10 μm to 120 μm, wherein the step elimination amount and the polishing amount are in angstrom units. ​ ​ ​ The ratio of the maximum value tanδ measured at 100 to 1000 rad / s of tanδ max100-1000 The ratio of the maximum value tanδ measured at 1 to 10 rad / s of tanδ max1-10 is 0.85 to 1.

15. ​ The ratio of the maximum value of tan δ measured at 0.1 to 10,000 rad / s to the minimum value of tan δ, i.e., maximum tan δ / minimum tan δ max0.1-10000 is 1 to 1.

3. min0.1-10000 is 1 to 1.

3. ​ The difference between the maximum and minimum values of tan δ measured at 0.1 to 10,000 rad / s, i.e. the maximum tan δ max0.1-10000 - the minimum tan δ min0.1-10000 is 0 to 0.

1. ​ ​ ​ The ratio of the value of the storage elastic modulus E' at 1000 rad / s, E' 1000 to the value of the storage elastic modulus E' at 10 rad / s, E' 10 was 1 to 2, that is, E' 1000 / E' 10 = 1 to 2, ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ the value E' of the E' at 1000 rad / s 1000 the value E' of the E' at 10 rad / s 10 ratio, i.e. E' 1000 / E' 10 is 1.4-1.

9. ​ ​ ​ ​ ​ ​

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