Method for manufacturing polishing pad and polished product

Abstract

To provide an abrasive pad which can obtain a polished product with excellent surface quality even while having an end point detection window, and a polished product manufacturing method with use of the same.SOLUTION: An abrasive pad has a polyurethane sheet as a polishing layer, and an end point detection window provided at an opening of the polyurethane sheet. In dynamic viscoelasticity measurement performed under the conditions of a tension mode, a frequency of 1.0 Hz, 10 to 100°C, a ratio (E'P30 / E'W30) of a storage elastic modulus E'P30 of the polyurethane sheet at 30°C to a storage elastic modulus E'W30 of the end point detection window at 30°C is 0.60 to 1.50.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a polishing pad and a method for producing a polished product using the same. [Background technology]

[0002] In the semiconductor manufacturing process, chemical mechanical polishing (CMP) is used for planarization after insulating film deposition and for forming metal wiring. One of the important technologies required for chemical mechanical polishing is the polishing end point detection to detect whether the polishing process is complete. For example, over-polishing or under-polishing with respect to the target polishing end point directly leads to product defects. Therefore, in chemical mechanical polishing, it is necessary to strictly control the amount of polishing by detecting the polishing end point.

[0003] Chemical mechanical polishing is a complex process, and the polishing speed (polishing rate) changes depending on the operating conditions of the polishing equipment, the quality of consumables (slurry, polishing pads, dressers, etc.), and the influence of variations in conditions over time during the polishing process. Furthermore, in recent years, the accuracy of the remaining film thickness and the uniformity of the surface are becoming increasingly strict in the semiconductor manufacturing process. For these reasons, it is becoming more difficult to detect the polishing end point with sufficient accuracy.

[0004] The main methods for detecting the polishing endpoint include the optical endpoint detection method, the torque endpoint detection method, and the eddy current endpoint detection method. In the optical endpoint detection method, the endpoint is detected by irradiating the wafer with light through a transparent window member provided on the polishing pad and monitoring the reflected light.

[0005] As an example of a polishing pad that uses such an optical endpoint detection method, Patent Document 1 discloses a polishing pad that has a pad body and a transparent window member formed integrally with a part of the pad body, with the aim of providing a polishing pad that can prevent slurry from accumulating in the grooves of the window member and thereby improve the detection accuracy of the polishing rate. The window member has a surface that is more abrasive than the material of the pad body. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2002-001647 A Summary of the Invention [Problem to be solved by the invention]

[0007] However, when the polishing layer and the end point detection window have different characteristics as in Patent Document 1, for example, the end point detection window portion is polished faster than the polishing layer and becomes a recess, where slurry and polishing debris are likely to accumulate, which may cause defects (surface defects). Also, if the end point detection window portion is polished slower than the polishing layer, the end point detection window becomes a convex portion as polishing progresses, which may cause defects and reduce the surface quality of the polished object.

[0008] The present invention has been made in consideration of the above-mentioned problems, and aims to provide a polishing pad that has an end point detection window but is less likely to produce defects and can produce a polished product with excellent surface quality, and a method for manufacturing a polished product using the same. [Means for solving the problem]

[0009] The present inventors have conducted extensive research to solve the above problems, and as a result have found that the above problems can be solved by providing a specific relationship between the endpoint detection window and the viscoelasticity of the polishing layer, thereby completing the present invention.

[0010] That is, the present invention is as follows. [1] The polishing method includes the steps of: (a) polishing a polishing layer formed in a polyurethane sheet; and (b) detecting an end point of the polishing layer by an end point detection window provided in an opening of the polyurethane sheet. In dynamic viscoelasticity measurement performed under conditions of tensile mode, frequency of 1.0 Hz, and temperature of 10 to 100°C, the storage modulus E' at 30°C in the end point detection window is W30 and the storage modulus E' of the polyurethane sheet at 30°C. P30 Ratio to (E'P30 / E' W30 ) is 0.60 to 1.50. Polishing pad. [2] The endpoint detection window contains polyurethane resin W. The polishing pad described in [1]. [3] The polyurethane resin W contains a structural unit derived from an alicyclic isocyanate and / or an aliphatic isocyanate. The polishing pad according to [2]. [4] The polyurethane resin W contains a structural unit derived from a compound having three or more hydroxyl groups. The polishing pad according to [2] or [3]. [5] In the dynamic viscoelasticity measurement, the storage modulus E' at 50°C in the end point detection window W50 and the storage modulus E' of the polyurethane sheet at 50°C. P50 Ratio to (E' P50 / E' W50 ) is 0.70 to 2.00, The polishing pad according to any one of [1] to [4]. [6] In the dynamic viscoelasticity measurement of the end point detection window, the storage modulus E' at 30°C W30 But, 10×10 7 ~60×10 7 Pa, The polishing pad according to any one of [1] to [5]. [7] The end point detection window has a hardness of 20°C (D W20 ) is between 40 and 70. The polishing pad according to any one of [1] to [6]. [8] The polyurethane sheet contains a polyurethane resin P and hollow fine particles dispersed in the polyurethane resin P. The polishing pad according to any one of [1] to [7]. [9] A polishing step of polishing an object to be polished using the polishing pad according to any one of [1] to [8] in the presence of a polishing slurry; and an end point detection step of detecting an end point during the polishing by an optical end point detection method. A method for manufacturing polished workpieces. Effect of the Invention

[0011] According to the present invention, it is possible to provide a polishing pad that has an end point detection window but is less likely to produce defects and can produce a polished product with excellent surface quality, and a method for manufacturing a polished product using the same. [Brief description of the drawings]

[0012] [Figure 1] 1 is a schematic perspective view of a polishing pad according to an embodiment of the present invention. [Diagram 2] 3 is a schematic cross-sectional view of an end point detection window portion of the polishing pad of the present embodiment. FIG. [Diagram 3] 10 is a schematic cross-sectional view of another aspect of the end point detection window portion of the polishing pad of the present embodiment. FIG. [Figure 4] FIG. 1 is a schematic diagram showing a film thickness control system installed in CMP. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] Hereinafter, an embodiment of the present invention (hereinafter referred to as "the present embodiment") will be described in detail with reference to the drawings as necessary, but the present invention is not limited to this, and various modifications are possible without departing from the gist of the present invention. In the drawings, the same elements are given the same symbols, and duplicated explanations will be omitted. Furthermore, positional relationships such as up, down, left, and right are based on the positional relationships shown in the drawings, unless otherwise specified. Furthermore, the dimensional ratios of the drawings are not limited to those shown in the drawings.

[0014] 1. Polishing pad The polishing pad of this embodiment has a polyurethane sheet that serves as a polishing layer, and an end point detection window provided at an opening of the polyurethane sheet. In dynamic viscoelasticity measurement performed under conditions of a tensile mode, a frequency of 1.0 Hz, and a temperature of 10 to 100° C., the storage modulus E′ at 30° C. of the end point detection window is W30 and the storage modulus E' of the polyurethane sheet at 30°C. P30 Ratio to (E' P30 / E' W30 ) is 0.60 to 1.50.

[0015] As a result, the dynamic viscoelastic properties of the polishing layer and the end point detection window become closer to each other during polishing, so that even if the end point detection window, which is a different material, is embedded in the polishing layer, the occurrence of defects (surface defects) on the surface of the workpiece is more suppressed, and therefore it is possible to obtain a polished workpiece with excellent surface quality.

[0016] A schematic perspective view of the polishing pad of this embodiment is shown in Fig. 1. As shown in Fig. 1, the polishing pad 10 of this embodiment has a polishing layer 11 which is a polyurethane sheet, and an end point detection window 12, and may have a cushion layer 13 on the side opposite to the polishing surface 11a, if necessary.

[0017] 2 and 3 show cross-sectional views of the periphery of the end point detection window 12 in FIG. 1. As shown in FIGS. 2 and 3, an adhesive layer 14 may be provided between the polishing layer 11 and the cushion layer 13, and an adhesive layer 15 for bonding to the table 22 in FIG. 4 may be provided on the surface of the cushion layer 13. The polishing surface 11a of the polishing pad of this embodiment may be flat as shown in FIG. 2, or may be uneven with grooves 16 formed therein as shown in FIG. 3. The grooves 16 may be formed by using a plurality of grooves of various shapes such as concentric circles, lattices, and radial patterns, either alone or in combination.

[0018] 1.1.End point detection window The end point detection window is a transparent member provided in an opening of the polyurethane sheet, and serves as a transmission path for light from the film thickness detection sensor in optical end point detection. In this embodiment, the end point detection window is circular, but may be square, rectangular, polygonal, elliptical, or other shapes as necessary.

[0019] In this embodiment, the ratio of the storage modulus E' of the end point detection window to that of the polyurethane sheet is specified in order to adjust the degree of wear of the end point detection window and the polishing layer during polishing and to prevent defects (surface defects) from occurring in the non-polished object due to excessive polishing of either the end point detection window or the polishing layer.

[0020] Dynamic Viscoelasticity In this embodiment, the storage modulus E' of the endpoint detection window and the polyurethane sheet can be determined by dynamic viscoelasticity measurement in a tensile mode at a frequency of 1.0 Hz and at 10 to 100° C. In this embodiment, the ratio of the storage modulus E' at 30° C. is specified from the viewpoint of expressing the characteristics of the endpoint detection window and the polyurethane sheet during polishing.

[0021] Storage modulus E' at 30°C in the end point detection window W30 and the storage modulus E' of the polyurethane sheet at 30°C P30 Ratio to (E' P30 / E' W30 The ratio (E') is 0.60 to 1.50, preferably 0.60 to 1.35, and more preferably 0.60 to 1.20. P30 / E' W30 ) within the above range, the characteristics of the endpoint detection window and the polyurethane sheet during polishing are similar, and the surface quality of the resulting polished object is further improved.

[0022] From the same viewpoint, in the dynamic viscoelasticity measurement, the storage modulus E' at 50°C of the end point detection window W50 and the storage modulus E' of the polyurethane sheet at 50°C P50 Ratio to (E' P50 / E' W50The ratio (E') is preferably 0.70 to 2.00, more preferably 0.70 to 1.85, and further preferably 0.70 to 1.70. P50 / E' W50 ) within the above range, the characteristics of the endpoint detection window and the polyurethane sheet during polishing are similar, and the surface quality of the resulting polished object tends to be improved.

[0023] In the dynamic viscoelasticity measurement of the end point detection window, the storage modulus E' at 30°C W30 is preferably 10 x 10 7 ~60×10 7 Pa, more preferably 15×10 7 ~55×10 7 Pa, and more preferably 20×10 7 ~50×10 7 Pa. Storage modulus E' W30 When the surface roughness is within the above range, the surface quality of the obtained polished object tends to be further improved.

[0024] The conditions for measuring the dynamic viscoelasticity are not particularly limited, but the measurement can be performed under the conditions described in the examples.

[0025] 1.1.2.D hardness D hardness at 20°C of the end point detection window (D W20 ) is 40 to 70, preferably 45 to 70, and more preferably 50 to 65. W20 ) within the above range tends to further suppress the occurrence of defects (surface defects).

[0026] The conditions for measuring the D hardness are not particularly limited, but the measurement can be performed under the conditions described in the Examples.

[0027] 1.1.3.Construction Materials The material constituting the end point detection window is not particularly limited as long as it is a transparent member capable of functioning as a window, and examples thereof include polyurethane resin W, polyvinyl chloride resin, polyvinylidene fluoride resin, polyethersulfone resin, polystyrene resin, polyethylene resin, polytetrafluoroethylene resin, etc. Among these, polyurethane resin W is preferable. By using such a resin, it is easier to adjust the dynamic viscoelastic properties, D hardness, and transparency.

[0028] The polyurethane resin W can be synthesized from a polyisocyanate and a polyol, and contains a structural unit derived from the polyisocyanate and a structural unit derived from the polyol.

[0029] 1.1.3.1. Polyisocyanate-derived building blocks The structural unit derived from polyisocyanate is not particularly limited, but examples thereof include structural units derived from alicyclic isocyanate, structural units derived from aliphatic isocyanate, and structural units derived from aromatic isocyanate. Among these, it is preferable that polyurethane resin W contains structural units derived from alicyclic isocyanate and / or aliphatic isocyanate. This makes it easier to adjust the dynamic viscoelasticity and D hardness within the above range, and transparency is further improved, and the yellowing resistance of the window tends to be further improved.

[0030] The alicyclic isocyanate is not particularly limited, but examples thereof include 4,4'-methylene-bis(cyclohexyl isocyanate) (hydrogenated MDI), cyclohexylene-1,2-diisocyanate, cyclohexylene-1,4-diisocyanate, and isophorone diisocyanate.

[0031] The aliphatic isocyanate is not particularly limited, but examples thereof include hexamethylene diisocyanate (HDI), pentamethylene diisocyanate (PDI), tetramethylene diisocyanate, propylene-1,2-diisocyanate, butylene-1,2-diisocyanate, trimethylene diisocyanate, and trimethylhexamethylene diisocyanate.

[0032] The aromatic isocyanate is not particularly limited, but examples thereof include phenylene diisocyanate, 2,6-tolylene diisocyanate (2,6-TDI), 2,4-tolylene diisocyanate (2,4-TDI), xylylene diisocyanate, naphthalene diisocyanate, and diphenylmethane-4,4'-diisocyanate (MDI).

[0033] 1.1.3.2. Polyol-derived building blocks The structural unit derived from a polyol is not particularly limited, but examples thereof include low molecular weight polyols having a molecular weight of less than 300 and high molecular weight polyols having a molecular weight of 300 or more.

[0034] The low molecular weight polyol is not particularly limited, but examples thereof include low molecular weight polyols having two hydroxyl groups such as ethylene glycol, propylene glycol, diethylene glycol, triethylene glycol, 1,2-butylene glycol, 1,3-butylene glycol, 2,3-butylene glycol, 1,4-butylene glycol, 1,5-pentanediol, neopentyl glycol, 1,6-hexane glycol, 2,5-hexanediol, dipropylene glycol, 2,2,4-trimethyl-1,3-pentanediol, tricyclodecane dimethanol, and 1,4-cyclohexane dimethanol; and low molecular weight polyols having three or more hydroxyl groups such as glycerin, hexanetriol, trimethylolpropane, isocyanuric acid, and erythritol. The low molecular weight polyols may be used alone or in combination of two or more.

[0035] Among these, a low molecular weight polyol having three or more hydroxyl groups is preferred, and glycerin is more preferred. By using such a low molecular weight polyol, it is easy to adjust the dynamic viscoelasticity and D hardness within the above range, the abrasion amount can be adjusted, the transparency is improved, and the yellowing resistance of the window tends to be improved.

[0036] The content of the structural units derived from a low molecular weight polyol having three or more hydroxyl groups is preferably 7.5 to 30 parts, more preferably 10 to 25 parts, and even more preferably 12.5 to 20 parts, relative to 100 parts of the structural units derived from a polyisocyanate. When the content of the structural units derived from a low molecular weight polyol having three or more hydroxyl groups is within the above range, the dynamic viscoelastic properties and D hardness can be easily adjusted to fall within the above range, transparency is further improved, and the yellowing resistance of the window tends to be further improved.

[0037] The polymer polyol is not particularly limited, but examples thereof include polyether polyol, polyester polyol, polycarbonate polyol, polyether polycarbonate polyol, polyurethane polyol, epoxy polyol, vegetable oil polyol, polyolefin polyol, acrylic polyol, and vinyl monomer modified polyol. The polymer polyol may be used alone or in combination of two or more kinds.

[0038] The number average molecular weight of the polymer polyol is preferably 300 to 3000, more preferably 500 to 2500, and further preferably 850 to 2000. By using such a polymer polyol, the dynamic viscoelastic properties and D hardness tend to be easily adjusted to within the above ranges.

[0039] Among these, polyether polyol is preferred, and polytetramethylene ether glycol is more preferred. By using such a polymer polyol, it is easy to adjust the dynamic viscoelasticity and D hardness within the above range, it is easy to adjust the hardness at low temperatures, and it is possible to suppress the decrease in hardness due to temperature rise. In addition, transparency is further improved, and the yellowing resistance of the window tends to be further improved.

[0040] The content of the structural units derived from polyether polyol is preferably 80 to 200 parts, more preferably 85 to 160 parts, and even more preferably 90 to 140 parts, relative to 100 parts of the structural units derived from polyisocyanate. When the content of the structural units derived from polyether polyol is within the above range, the dynamic viscoelastic properties and D hardness can be easily adjusted to fall within the above range, transparency is further improved, and the yellowing resistance of the window tends to be further improved.

[0041] As the polyol, it is preferable to use a low molecular weight polyol in combination with a high molecular weight polyol, and it is more preferable to use a low molecular weight polyol having three or more hydroxyl groups in combination with a polyether polyol, which makes it easier to adjust the dynamic viscoelasticity and D hardness within the above ranges, improves transparency, and tends to improve the yellowing resistance of the window.

[0042] From the above viewpoints, the content of the polyether polyol is preferably 2.0 to 15.0 parts, more preferably 3.0 to 12.5 parts, and even more preferably 4.0 to 9.0 parts, per part of the low molecular weight polyol having three or more hydroxyl groups.

[0043] 1.2. Polishing layer In this embodiment, a polyurethane sheet is used as the polishing layer. This polyurethane sheet has an opening in which an end point detection window is embedded. The position of the opening is not particularly limited, but it is preferable to provide it at a radial position corresponding to the film thickness detection sensor 23 installed on the table 22. In addition, the number of openings is not particularly limited, but it is preferable to have multiple openings at similar radial positions so that the window passes over the film thickness detection sensor 23 multiple times when the polishing pad 10 attached to the table 22 rotates once.

[0044] The form of the polyurethane sheet is not particularly limited, but examples thereof include a foamed polyurethane sheet, a non-foamed polyurethane sheet made of resin, and a sheet in which a fiber base material is impregnated with polyurethane.

[0045] Here, the foamed resin body refers to a foamed resin body that does not have a fiber substrate. The foam shape is not particularly limited, but examples thereof include spherical bubbles, nearly spherical bubbles, teardrop-shaped bubbles, and open bubbles in which each bubble is partially connected.

[0046] In addition, the non-foamed resin molded body refers to a non-foamed body that does not have a fiber substrate and is composed of a specific resin. The non-foamed body refers to a body that does not have bubbles as described above. In the first embodiment, the non-foamed resin molded body also includes a body that is formed by attaching a curable composition to a substrate such as a film and curing it. More specifically, the non-foamed resin molded body also includes a resin cured product formed by a labia coater method, a small diameter gravure coater method, a reverse roll coater method, a transfer roll coater method, a kiss coater method, a die coater method, a screen printing method, a spray coating method, or the like.

[0047] Furthermore, the resin-impregnated substrate refers to a substrate obtained by impregnating a fiber substrate with a resin. The fiber substrate is not particularly limited, but examples thereof include woven fabric, nonwoven fabric, and knitted fabric.

[0048] Dynamic Viscoelasticity In the dynamic viscoelasticity measurement of the polishing layer, the storage modulus E' at 30°C P30 is preferably 15 x 10 7 ~65×10 7 Pa, more preferably 20×10 7 ~60×10 7 Pa, and more preferably 25×10 7 ~55×10 7 Pa. Storage modulus E' P30 When the surface roughness is within the above range, the surface quality of the obtained polished object tends to be further improved.

[0049] In the dynamic viscoelasticity measurement of the polishing layer, the storage modulus E' at 50°C P50 is preferably 10 x 10 7 ~40×10 7 Pa, more preferably 15×10 7 ~35×107 Pa, and more preferably 20×10 7 ~30×10 7 Pa. Storage modulus E' P50 When the surface roughness is within the above range, the surface quality of the obtained polished object tends to be further improved.

[0050] 1.2.2.Polyurethane sheet The polyurethane resin P constituting the polyurethane sheet is not particularly limited, but examples thereof include polyester-based polyurethane resins, polyether-based polyurethane resins, and polycarbonate-based polyurethane resins. These may be used alone or in combination of two or more.

[0051] Such polyurethane resin P can be synthesized from polyisocyanate and polyol, and in particular, a reaction product of urethane prepolymer and curing agent is preferable. Here, the urethane prepolymer can be synthesized from polyisocyanate and polyol. The polyisocyanate, polyol, and curing agent constituting the polyurethane resin P will be described below.

[0052] 1.2.2.1. Polyisocyanate-derived building blocks The polyisocyanate-derived structural unit is not particularly limited, and examples thereof include alicyclic isocyanate-derived structural units, aliphatic isocyanate-derived structural units, and aromatic isocyanate-derived structural units. Among these, aromatic isocyanates are preferred, and 2,4-tolylene diisocyanate (2,4-TDI) is more preferred.

[0053] Examples of the alicyclic isocyanate, aliphatic isocyanate, and aromatic isocyanate include the same ones as those exemplified in the above endpoint detection window.

[0054] 1.2.2.2. Polyol-derived building blocks The structural unit derived from a polyol is not particularly limited, and examples thereof include low molecular weight polyols having a molecular weight of less than 300 and high molecular weight polyols having a molecular weight of at least 300. Among these, it is preferable to use at least a low molecular weight polyol, and it is preferable to use a low molecular weight polyol and a high molecular weight polyol in combination.

[0055] Examples of the low molecular weight polyol and the high molecular weight polyol are the same as those exemplified in the above-mentioned end point detection window. Among these, the low molecular weight polyol is preferably a low molecular weight polyol having two hydroxyl groups, and more preferably diethylene glycol. Also, the high molecular weight polyol is preferably a polyether polyol, and more preferably polytetramethylene ether glycol.

[0056] 1.2.2.3. Hardener The curing agent is not particularly limited, but examples thereof include polyamines and polyols. The curing agent may be used alone or in combination of two or more kinds.

[0057] The polyamine is not particularly limited, but examples thereof include aliphatic polyamines such as ethylenediamine, propylenediamine, and hexamethylenediamine; alicyclic polyamines such as isophoronediamine and dicyclohexylmethane-4,4'-diamine; and aromatic polyamines such as 3,3'-dichloro-4,4'-diaminodiphenylmethane (MOCA), 4-methyl-2,6-bis(methylthio)-1,3-benzenediamine, 2-methyl-4,6-bis(methylthio)-1,3-benzenediamine, and 2,2-bis(3-amino-4-hydroxyphenyl)propane.

[0058] Among these, aromatic polyamines are preferred, and it is more preferred to use 3'-dichloro-4,4'-diaminodiphenylmethane (MOCA).

[0059] Examples of the polyol include the same polyols as those exemplified in the above-mentioned end point detection window. Among these, polymer polyols are preferred, polyether polyols are more preferred, and polypropylene glycol is even more preferred.

[0060] 1.2.2.4.Hollow particles The polyurethane sheet is preferably a foamed polyurethane sheet containing polyurethane resin P and hollow fine particles dispersed in the polyurethane resin P. Such a polyurethane sheet has closed cells derived from the hollow fine particles, and tends to have the dynamic viscoelastic properties and D hardness easily adjusted to within the above ranges.

[0061] The hollow microparticles may be commercially available or may be synthesized by a conventional method. The material of the shell of the hollow microparticles is not particularly limited, and examples thereof include polyvinyl alcohol, polyvinylpyrrolidone, poly(meth)acrylic acid, polyacrylamide, polyethylene glycol, polyhydroxyether acrylate, maleic acid copolymer, polyethylene oxide, polyurethane, acrylonitrile-vinylidene chloride copolymer, acrylonitrile-methyl methacrylate copolymer, vinyl chloride-ethylene copolymer, etc.

[0062] The shape of the hollow microparticles is not particularly limited, and may be, for example, spherical or nearly spherical. When the hollow microparticles are expandable balloons, they may be used in an unexpanded state or in an expanded state.

[0063] The average particle size of the hollow fine particles contained in the polyurethane sheet 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. When the average particle size is within the above range, the dynamic viscoelastic properties and D hardness tend to be easily adjusted to be within the above range. The average particle size can be measured by a laser diffraction particle size distribution measuring device (for example, Mastersizer 2000, manufactured by Spectris Co., Ltd.).

[0064] 1.3.Other The polishing pad of this embodiment may have a cushion layer on the opposite side of the polishing surface of the polishing layer, or may have an adhesive layer between the polishing layer and the cushion layer, or on the surface of the cushion layer other than the polishing layer (the surface to be attached to the polishing machine). In this case, the cushion layer and the adhesive layer have an opening in the same position as the end point detection window of the polishing layer.

[0065] 2. Manufacturing method of polishing pad The method for manufacturing the polishing pad of this embodiment is not particularly limited, but may, for example, include the steps of filling a resin composition constituting the polishing layer into a mold to which a window member that will serve as an endpoint detection window is fixed, and curing the resin composition to obtain a resin block in which the window member is embedded, and slicing the obtained resin block to obtain a polyurethane sheet having an endpoint detection window in an opening thereof, and the polishing surface of the obtained polyurethane sheet may be dressed, if necessary.

[0066] The temperature during slicing is preferably 70 to 100°C. The temperature during dressing is preferably 20 to 30°C.

[0067] 3. Manufacturing method of polished products The method for producing a polished product of this embodiment includes a polishing step in which the polishing pad is used to polish a workpiece in the presence of a polishing slurry to obtain a polished product, and an end point detection step in which an optical end point detection method is used to detect the end point during the polishing.

[0068] 3.1. Polishing process The polishing process may be a primary lapping process (rough lapping), a secondary lapping process (finish lapping), a primary polishing process (rough polishing), a secondary polishing process (finish polishing), or a process that combines these processes. Note that, here, "lapping" refers to polishing at a relatively high rate using coarse abrasive grains, and "polishing" refers to polishing at a relatively low rate using fine abrasive grains to improve the surface quality.

[0069] Among these, the polishing pad of the present embodiment is preferably used for chemical mechanical polishing (CMP). Hereinafter, the method for producing the polished product of the present embodiment will be described taking chemical mechanical polishing as an example, but the method for producing the polished product of the present embodiment is not limited to the following.

[0070] The object to be polished is not particularly limited, but examples thereof include materials such as semiconductor devices and electronic components, particularly thin substrates (objects to be polished) such as Si substrates (silicon wafers), SiC (silicon carbide) substrates, GaAs (gallium arsenide) substrates, glass, hard disks, LCD (liquid crystal display) substrates, etc. In particular, semiconductor devices having metal wiring such as W (tungsten) and Cu (copper) are included.

[0071] The polishing method may be a conventionally known method, and is not particularly limited. For example, first, the object to be polished held on a holding platen arranged to face the polishing pad is pressed against the polishing surface, and the polishing pad and / or the holding platen are rotated while supplying a slurry from the outside. The polishing pad and the holding platen may rotate in the same direction at different rotation speeds, or in different directions. The object to be polished may be polished while moving (rotating) inside the frame during the polishing process.

[0072] The slurry may contain water, chemical components such as an oxidizing agent such as hydrogen peroxide, additives, abrasive grains (polishing particles; for example, SiC, SiO2, Al2O3, CeO2), etc. depending on the object to be polished and the polishing conditions.

[0073] 3.2.End point detection process The method for manufacturing a polished product according to the present embodiment includes an end point detection step in which an end point is detected by an optical end point detection method in the polishing step. As the end point detection method by the optical end point detection method, specifically, a conventionally known method can be used.

[0074] 4 shows a schematic diagram of an optical end point detection method. This schematic diagram shows a chemical mechanical polishing process in which a wafer W held by a top ring 21 is pressed against a polishing pad 10 attached to a table 22 while a slurry 24 is flowing thereon to remove the uneven film on the surface of the wafer W and flatten it. The polishing apparatus 20 is equipped with a film thickness detection sensor 23 on the table 22 for monitoring the film thickness in order to end the process accurately by detecting a predetermined film thickness at the same time as flattening. The film thickness detection sensor 23 can detect the polishing end point by, for example, irradiating light onto the polished surface of the wafer W and measuring and analyzing the spectral intensity characteristics of the reflected light.

[0075] More specifically, the film thickness detection sensor 23 can detect a change in film thickness by irradiating light onto the surface of the wafer W through the end point detection window 12 and detecting the strength of reflection intensity caused by the phase difference between the light reflected by the film on the wafer W (wafer surface) and the light reflected at the interface between the film on the wafer W and the wafer substrate. EXAMPLES

[0076] The present invention will be described in more detail below using examples and comparative examples. The present invention is not limited to the following examples. In addition, "parts" refers to parts by mass.

[0077] [Production Example 1: End Point Detection Window 1] A transparent member that becomes the endpoint detection window 1 was obtained by reacting 100 parts of 4,4' methylene bis (cyclohexyl isocyanate), 120.9 parts of poly (oxytetramethylene) glycol (PTMG) having a number average molecular weight of 1000, and 14.8 parts of glycerin.

[0078] [Production Example 2: End Point Detection Window 2] A transparent member to become the endpoint detection window 2 was obtained by reacting 100 parts of 4,4' methylene bis (cyclohexyl isocyanate), 103.6 parts of poly (oxytetramethylene) glycol (PTMG) having a number average molecular weight of 1000, and 15.9 parts of glycerin.

[0079] [Production Example 3: End Point Detection Window 3] A transparent member to become the end point detection window 3 was obtained by reacting 100 parts of 4,4' methylene bis (cyclohexyl isocyanate), 96.7 parts of poly (oxytetramethylene) glycol (PTMG) having a number average molecular weight of 1000, and 16.3 parts of glycerin.

[0080] [Production Example 4: End Point Detection Window 4] A transparent member to become the end point detection window 4 was obtained by reacting 100 parts of 4,4' methylene bis (cyclohexyl isocyanate), 90.6 parts of poly (oxytetramethylene) glycol (PTMG) having a number average molecular weight of 1000, and 16.7 parts of glycerin.

[0081] [Production Example 5: End Point Detection Window 5] A transparent member that becomes the end point detection window 5 was obtained by reacting 100 parts of 4,4' methylene bis (cyclohexyl isocyanate), 78.6 parts of poly (oxytetramethylene) glycol (PTMG) having a number average molecular weight of 650, and 14.8 parts of glycerin.

[0082] [Production Example 6: End Point Detection Window 6] A transparent member that would become the endpoint detection window 6 was obtained by reacting 100 parts of 4,4'methylenebis(cyclohexyl isocyanate), 78.6 parts of poly(oxytetramethylene) glycol (PTMG) having a number average molecular weight of 650, 10.5 parts of ethylene glycol, and 4.5 parts of glycerin.

[0083] Example 1 2,4-tolylene diisocyanate (2,4-TDI), poly(oxytetramethylene) glycol (PTMG) with an average molecular weight of 650, poly(oxytetramethylene) glycol (PTMG) with a number average molecular weight of 1000, and diethylene glycol (DEG) were reacted to form 100 parts of a urethane prepolymer with an NCO equivalent of 455. The shell part was made of an acrylonitrile-vinylidene chloride copolymer, and 2.7 parts of unexpanded hollow fine particles (average particle size: 8.5 μm) were added and mixed to obtain a urethane prepolymer mixture. The obtained urethane prepolymer mixture was charged into a first liquid tank and kept at 60 ° C. In addition, 25.8 parts of 3,3'-dichloro-4,4'-diaminodiphenylmethane (methylenebis-o-chloroaniline) (MOCA) were added to a second liquid tank as a curing agent, and the mixture was heated and melted at 120 ° C. and mixed, and further degassed under reduced pressure to obtain a curing agent melt.

[0084] Next, the liquids in the first liquid tank and the second liquid tank were poured into a mixer having two injection ports, respectively, and mixed by stirring to obtain a mixed liquid.

[0085] The mixture was poured into a mold in which the end point detection window 1 obtained as described above had been previously installed, and was primarily cured at 80°C for 30 minutes. The block-shaped molded product thus formed was removed from the mold and was secondary cured in an oven at 120°C for 4 hours to obtain a urethane resin block. The obtained urethane resin block was allowed to cool to 25°C.

[0086] After that, it was heated again in an oven at 120°C for 5 hours, then sliced, and the sliced ​​surface was ground (buffed) to obtain a foamed polyurethane sheet. Double-sided tape was attached to the back surface of the obtained polyurethane sheet, a cushion layer was attached, and further double-sided tape was attached to the surface of the cushion layer to obtain a polishing pad.

[0087] Example 2 2.9 parts of unexpanded hollow fine particles (average particle size: 8.5 μm) whose shell portion is made of acrylonitrile-vinylidene chloride copolymer were added and mixed with 100 parts of urethane prepolymer having an NCO equivalent of 420, which was obtained by reacting 2,4-tolylene diisocyanate (2,4-TDI), poly(oxytetramethylene) glycol (PTMG) having an average molecular weight of 650, poly(oxytetramethylene) glycol (PTMG) having a number average molecular weight of 1000, and diethylene glycol (DEG), to obtain a urethane prepolymer mixture. The obtained urethane prepolymer mixture was charged into a first liquid tank and kept at 60°C. In addition to the first liquid tank, 28.0 parts of 3,3'-dichloro-4,4'-diaminodiphenylmethane (methylene bis-o-chloroaniline) (MOCA) was placed in a second liquid tank as a hardener, which was then heated to 120°C to melt and mix, and then degassed under reduced pressure to obtain a hardener molten liquid. A polishing pad was obtained in the same manner as in Example 1, except that an end point detection window 2 was used.

[0088] Example 3 2,4-tolylene diisocyanate (2,4-TDI), poly(oxytetramethylene) glycol (PTMG) having an average molecular weight of 650, and diethylene glycol (DEG) were reacted to obtain 100 parts of a urethane prepolymer having an NCO equivalent of 460, and 2.8 parts of hollow fine particles (average particle size: 20 μm) whose shell portion is made of an acrylonitrile-vinylidene chloride copolymer were added and mixed to obtain a urethane prepolymer mixed liquid. The obtained urethane prepolymer mixed liquid was charged into a first liquid tank and kept at 60 ° C. In addition, apart from the first liquid tank, 25.5 parts of 3,3'-dichloro-4,4'-diaminodiphenylmethane (methylene bis-o-chloroaniline) (MOCA) and 8.5 parts of polypropylene glycol were charged into a second liquid tank as a curing agent, and the curing agent melt liquid obtained by heating and melting at 120 ° C. and mixing, and further degassing under reduced pressure was obtained. Except for this, a polishing pad was obtained in the same manner as in Example 1.

[0089] Example 4 A polishing pad was obtained in the same manner as in Example 1, except that the end point detection window 2 was used.

[0090] Example 5 A polishing pad was obtained in the same manner as in Example 1, except that the end point detection window 3 was used.

[0091] Example 6 A polishing pad was obtained in the same manner as in Example 1, except that the end point detection window 4 was used.

[0092] Example 7 A polishing pad was obtained in the same manner as in Example 2, except that the end point detection window 4 was used.

[0093] Comparative Example 1 A polishing pad was obtained in the same manner as in Example 1, except that the end point detection window 5 was used.

[0094] Comparative Example 2 A polishing pad was obtained in the same manner as in Example 1, except that the end point detection window 6 was used.

[0095] [Dynamic viscoelasticity measurement] Under the following conditions, a polyurethane sheet was kept in a thermo-hygrostat at a temperature of 23°C (±2°C) and a relative humidity of 50% (±5%) for 40 hours, and the resulting dry polyurethane sheet was used as a sample to perform dynamic viscoelasticity measurements in normal atmospheric air (dry state).The sample size of the endpoint detection window was 5cm long x 0.5cm wide x 0.125cm thick, and the sample size of the polishing layer was 5cm long x 0.5cm wide x 0.13cm thick. (Measurement conditions) Measurement device: RSA III (TA Instruments) Test length: 1cm Test mode: Tensile Frequency: 1.0Hz Temperature range: 10~100℃ Heating rate: 3.0℃ / min Distortion range: 0.10% Initial load: 300g Measurement interval: 1.5 points / ℃

[0096] [D hardness] The D hardness was measured according to JIS K6253. A D hardness tester manufactured by Tecrock Corporation was used for the measurement, and the sample was set so that the end point detection window (thickness: about 0.125 cm (1.25 mm)) described in the Comparative Examples and Examples was stacked four times, and the total thickness was at least 0.45 cm (4.5 mm).

[0097] [Surface quality verification test] The polishing pad was placed at a predetermined position in the polishing device via a double-sided tape having an acrylic adhesive, and the Cu film substrate was polished under the following conditions. (polishing conditions) Grinding machine: F-REX300X (manufactured by Ebara Corporation) Disk: A188 (3M) Rotation speed: (table) 85 rpm, (top ring) 86 rpm Grinding pressure: 3.5psi Polishing agent temperature: 20℃ Abrasive discharge rate: 200ml / min Abrasive: CSL-9044C (manufactured by Fujimi Corporation) (A mixture of CSL-9044C stock solution and pure water (weight ratio: 1:9) was used. Object to be polished: Cu film substrate Polishing time: 60 seconds Pad break: 35N 10 minutes Conditioning: Ex-situ, 35N, 4 scans

[0098] For the 10th to 50th polished pieces after the above polishing process, defects (surface defects) with a size of 155 nm or more were detected and evaluated using the high sensitivity measurement mode of a surface inspection device (KLA Tencor, Surfscan SP2XP).The surface quality was evaluated based on the results of defect (surface defect) confirmation.

[0099] [Table 1] [Industrial Applicability]

[0100] The polishing pad of the present invention has industrial applicability as a pad that is suitably used for polishing semiconductor wafers and the like. [Explanation of symbols]

[0101] 10...polishing pad, 11...polishing layer, 11a...polishing surface, 12...end point detection window, 13...cushion layer, 14, 15...adhesive layer, 16...groove, 20...polishing device, 21...top ring, 22...table, 23...film thickness detection sensor, 24...slurry, W...wafer

Claims

1. The polishing method includes the steps of: (a) polishing a polishing layer formed in a polyurethane sheet; and (b) detecting an end point of the polishing layer by an end point detection window provided in an opening of the polyurethane sheet. The polyurethane sheet contains a polyurethane resin P and hollow fine particles dispersed in the polyurethane resin P, the end point detection window contains polyurethane resin W, the polyurethane resin W comprises a structural unit derived from an alicyclic isocyanate, a structural unit derived from a compound having three or more hydroxyl groups, and a structural unit derived from a polyether polyol, In dynamic viscoelasticity measurement performed under conditions of tensile mode, frequency of 1.0 Hz, and temperature of 10 to 100° C., the storage modulus E′ at 30° C. in the end point detection window is W30 and the storage modulus E' of the polyurethane sheet at 30°C. P30 The ratio of (E' P30 / E' W30 ) is 0.60 to 1.50; Polishing pad.

2. In the dynamic viscoelasticity measurement, the storage modulus E′ at 50° C. in the end point detection window W50 and the storage modulus E' of the polyurethane sheet at 50°C. P50 The ratio of (E' P50 / E' W50 ) is 0.70 to 2.00; The polishing pad of claim 1.

3. In the dynamic viscoelasticity measurement of the end point detection window, the storage modulus E' at 30°C W30 But, 10 x 10 7 ~60 x 10 7 Pa, 3. The polishing pad according to claim 1 or 2.

4. The end point detection window has a D hardness at 20° C. (D W20 ) is 40 to 70, The polishing pad according to any one of claims 1 to 3.

5. A polishing step of polishing an object to be polished using the polishing pad according to any one of claims 1 to 4 in the presence of a polishing slurry; and an end point detection step of detecting an end point during the polishing by an optical end point detection method. A method for manufacturing polished workpieces.

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