JP7518645B2 - Polishing unit, polishing apparatus, and method for manufacturing polishing pad - Google Patents

Description

The present invention relates to a polishing unit, a polishing device, a polishing pad, and a method for manufacturing a polishing pad.

A polishing pad generally has a laminated structure in which a polishing layer that comes into contact with the material to be polished and a base layer that supports the polishing layer and has the same planar shape and size as the polishing layer are attached with double-sided tape. In the polishing process, polishing slurry is supplied to the center of the polishing pad, and the material to be polished and the polishing pad are moved relative to each other to perform polishing. However, there is a problem in that the polishing slurry penetrates into the base layer from the outer peripheral side, causing the double-sided tape to peel off from the base layer. As a technology to solve this problem, Patent Document 1 discloses a polishing pad that includes a polishing layer and a lower layer, and the lower layer is treated to be water-repellent. Patent Document 2 discloses a polishing pad in which a waterproof layer is provided on the peripheral side of a base layer that is smaller in size than the pad body.

JP 2004-311722 A JP 2002-36097 A

However, the invention described in Patent Document 1 has a problem in that the adhesion between the lower layer and the double-sided tape is reduced by applying a water-repellent treatment to the surface of the lower layer. In addition, in the invention described in Patent Document 2, when the polishing pad is attached to the base plate of the polishing device, the pad body is larger than the base layer, so the base layer that is attached to the base plate cannot be visually confirmed. As a result, the polishing pad may be attached in a state where it is misaligned from the base plate. If the polishing pad is polished in a state where it is misaligned from the base plate, the center of gravity is shifted, which causes a problem in that the polishing performance is reduced.

One aspect of the present invention aims to provide a polishing unit that can reduce the penetration of polishing slurry into the base layer and prevent a decrease in polishing performance.

In order to solve the above problem, a polishing unit according to one aspect of the present invention is a polishing unit including a polishing pad and a base plate, the polishing pad being formed by laminating a polishing layer, a first adhesive layer, a base layer including a nonwoven fabric, and a second adhesive layer in this order, the polishing pad being attached to the base plate via the second adhesive layer, the diameter of the base layer being smaller than the diameter of the polishing layer and larger than the diameter of the base plate, the base layer being positioned so as to be located inside the polishing layer when viewed in a plan view from the base plate side, and the base plate being positioned so as to be located inside the base layer.

In order to solve the above problem, the polishing pad according to one embodiment of the present invention comprises a polishing layer, a first adhesive layer, a base layer including a nonwoven fabric, and a second adhesive layer, which are stacked concentrically in this order, and the diameter of the base layer is smaller than the diameter of the polishing layer.

In order to solve the above-mentioned problems, a method for manufacturing an abrasive pad according to one aspect of the present invention is a method for manufacturing an abrasive pad having an abrasive layer and a base layer, and includes a lamination step for obtaining a laminated pad in which an abrasive sheet, a first adhesive sheet, a base sheet including a nonwoven fabric, and a second adhesive sheet are laminated in this order, and a cutting step for cutting the laminated pad by inserting a die having a cutting blade on a base thereof for cutting the laminated pad into the shape of the abrasive layer and a cutting blade for cutting the laminated pad into the shape of the base layer into the laminated pad from the side of the second adhesive sheet, the cutting blade being disposed in the front The cutting blade is provided on the inside of the cutting blade, the height of the cutting blade is equal to or greater than the thickness of the laminated pad, the height of the incision blade is equal to or greater than the total thickness of the base sheet and the second adhesive sheet, and the difference between the heights of the cutting blade and the incision blade is equal to the thickness of the polishing sheet or the total thickness of the polishing sheet and the first adhesive sheet, and the method further includes a peeling step of obtaining the polishing pad by peeling off the base sheet and the second adhesive sheet in the outer portion of the incision from the laminated pad cut into the shape of the polishing layer.

According to one aspect of the present invention, it is possible to provide a polishing unit that can reduce the penetration of polishing slurry into the base material layer and prevent a decrease in polishing performance.

1 is a schematic diagram showing a configuration of a polishing apparatus according to a first embodiment of the present invention. 1 is a cross-sectional view showing a configuration of a polishing unit according to a first embodiment of the present invention. 2 is a top view showing a die used in the method for manufacturing a polishing pad according to the first embodiment of the present invention. FIG. 2 is a cross-sectional view of a die used in a method for manufacturing a polishing pad according to the first embodiment of the present invention. FIG. 2A to 2C are schematic diagrams illustrating a method for manufacturing a polishing pad according to the first embodiment of the present invention. FIG. 6 is a cross-sectional view showing a configuration of a polishing unit according to a second embodiment of the present invention. FIG. 11 is a cross-sectional view showing a configuration of a polishing unit according to a third embodiment of the present invention.

The following describes an embodiment of the present invention in detail.

[Embodiment 1]
[Polishing equipment]
1 is a schematic diagram showing the configuration of a polishing apparatus according to the present embodiment. As shown in FIG. 1, the polishing apparatus 1 includes a polishing unit 10a, a holding unit 20, and a polishing-slurry supply unit 30.

The polishing unit 10a is a unit for polishing the material 40 held in the holding unit 20. The holding unit 20 is disposed above the polishing unit 10a and is a unit for holding the material 40. The polishing slurry supplying section 30 is a member for supplying polishing slurry onto the polishing surface 101a, which is the surface of the polishing layer 101 of the polishing unit 10a.

The material 40 to be polished is held by the holding unit 20 so that the surface to be polished is in contact with the polishing unit 10a and is sandwiched between the polishing unit 10a and the holding unit 20. In this state, the polishing unit 10a and the holding unit 20 rotate, allowing the polishing unit 10a to polish the material 40 to be polished.

The polishing apparatus 1 can be used, for example, to polish optical materials, semiconductor devices, and substrates for hard disks, and is particularly suitable for polishing devices in which oxide layers and metal layers are formed on semiconductor wafers.

(Polishing unit)
Fig. 2 is a cross-sectional view showing the configuration of the polishing unit 10a according to this embodiment. As shown in Fig. 2, the polishing unit 10a includes a polishing pad 100a and a platen 150. The polishing pad 100a has a configuration in which a polishing layer 101, a first adhesive layer 102, a base layer 103, and a second adhesive layer 104 are laminated in this order. The polishing pad 100a is attached to the platen 150 via the second adhesive layer 104.

2, the diameter of the base layer 103 is smaller than the diameter of the polishing layer 101, and the base layer 103 is arranged so as to be contained inside the polishing layer 101 when viewed in plan from the platen 150 side. This configuration reduces the amount of polishing slurry that reaches the side of the base layer 103 during polishing, compared to when the polishing layer and the base layer have the same diameter. Therefore, even if the base layer 103 is not subjected to a water-repellent treatment, the penetration of the polishing slurry into the base layer 103 can be reduced. By reducing the penetration of the polishing slurry into the base layer 103, the adhesion between the base layer 103 and the first adhesive layer 102 and the adhesion between the base layer 103 and the second adhesive layer 104 can be maintained. The difference between the diameter of the base layer 103 and the diameter of the polishing layer 101 is preferably 1 mm or more, more preferably 1.5 mm or more, and even more preferably 2 mm or more, from the viewpoint of reducing the penetration of the polishing slurry into the base layer 103. Moreover, from the viewpoint of making it difficult for the polishing layer 101 to peel off from the base layer 103, the difference is preferably 10 mm or less, more preferably 7.5 mm or less, and even more preferably 5 mm or less.

In addition, in this embodiment, the polishing layer 101 and the base layer 103 are stacked concentrically. This configuration makes the distance from the edge of the polishing layer 101 to the base layer 103 uniform, and uniformly prevents the polishing slurry from reaching the base layer 103.

The diameter of the base layer 103 is larger than the diameter of the platen 150. This is a configuration adopted to solve the problem of bonding the polishing pad 100a to the platen 150. In other words, this configuration makes it possible to prevent misalignment between the platen 150 and the polishing pad 100a when bonding the polishing pad 100a to the platen 150. The difference between the diameter of the base layer 103 and the diameter of the platen 150 is preferably 1 mm or more, more preferably 2 mm or more, and even more preferably 3 mm or more, from the viewpoint of preventing misalignment of the bonding between the platen 150 and the polishing pad 100a. In addition, the difference is preferably 20 mm or less, more preferably 17 mm or less, and even more preferably 13 mm or less, from the viewpoint of making it difficult for the polishing pad 100a to peel off from the platen 150.

When viewed from above, the base plate 150 is arranged so as to be located inside the base layer 103. This configuration makes it possible to prevent the polishing pad 100a from peeling off from the base plate 150. In addition, when viewed from above, the base plate 150 and the base layer 103 are concentric. However, the present invention is not limited to this, and the center of the base plate 150 and the center of the base layer 103 may be misaligned as long as the base plate 150 is arranged so as to be located inside the base layer 103 when viewed from above.

(Polishing pad)
The polishing pad 100a can be used in the same manner as a general polishing pad. For example, the polishing layer 101 can be pressed against the material to be polished 40 while rotating the polishing pad 100a, or the material to be polished 40 can be pressed against the polishing layer 101 while rotating the material to be polished.

(Polishing layer)
The polishing layer 101 is a layer that polishes the material to be polished 40. The polishing layer 101 is disposed in the polishing unit 10a at a position that directly contacts the material to be polished 40. The polishing surface 101a, which is the surface of the polishing layer 101, may have holes or grooves for facilitating retention of the polishing slurry, or grooves for facilitating discharge of the polishing slurry.

The material of the polishing layer 101 may be any material capable of polishing the material 40 to be polished, and may be appropriately selected depending on the type of material 40 to be polished. For example, from the viewpoint of being able to suitably polish optical materials, semiconductor devices, hard disk substrates, etc., the material of the polishing layer 101 is preferably a polyurethane foam resin.

The diameter of the polishing layer 101 can be appropriately selected depending on the size of the material 40 to be polished, and can be, for example, 700 mm or more, or 750 mm or more, or 850 mm or less, or 800 mm or less.

The thickness of the polishing layer 101 can be appropriately selected depending on the material of the workpiece 40 to be polished and the life required in the polishing process, and can be, for example, 1.0 mm or more, or 1.2 mm or more, and 3.0 mm or less, or 2.0 mm or less.

(Base layer)
The base material layer 103 is formed using a nonwoven fabric. The nonwoven fabric in this embodiment is not particularly limited, and various known nonwoven fabrics can be adopted. Examples of nonwoven fabrics include polyolefin-based, polyamide-based, and polyester-based nonwoven fabrics. In addition, the method of entangling fibers when obtaining the nonwoven fabric is not particularly limited, and may be, for example, needle punching or water flow entanglement. The nonwoven fabric may be one type selected from the above, or may be used in combination of two or more types. Nonwoven fabrics have many gaps between fibers and are naturally highly absorbent, but by impregnating the nonwoven fabric with resin, the gaps are filled with resin, and the absorbency is reduced.

The base material layer 103 is preferably made of an impregnated nonwoven fabric impregnated with a resin. Examples of the resin include polyurethanes such as polyurethane and polyurethane polyurea, acrylics such as polyacrylate and polyacrylonitrile, vinyls such as polyvinyl chloride, polyvinyl acetate and polyvinylidene fluoride, polysulfones such as polysulfone and polyethersulfone, acylated celluloses such as acetylated cellulose and butyrylated cellulose, polyamides and polystyrenes. The density of the nonwoven fabric is preferably 0.3 g/cm ³ or less, more preferably 0.1 to 0.2 g/cm ³ , before the resin is impregnated (web state). The density of the nonwoven fabric after the resin is impregnated is preferably 0.7 g/cm ³ or less, more preferably 0.3 to 0.5 g/cm ^3. The density of the nonwoven fabric before and after the resin is impregnated is equal to or less than the upper limit, thereby improving the processing accuracy. In addition, by making the density of the nonwoven fabric before and after the resin impregnation equal to or higher than the lower limit, it is possible to reduce the penetration of the polishing slurry into the base layer 103. The adhesion rate of the resin to the nonwoven fabric is expressed as the weight of the resin adhered to the weight of the nonwoven fabric, and is preferably 50% by weight or more, and more preferably 75 to 200% by weight. By making the adhesion rate of the resin to the nonwoven fabric equal to or lower than the upper limit, it is possible to obtain the desired cushioning properties as a base layer. In addition, by making the adhesion rate of the resin to the nonwoven fabric equal to or higher than the lower limit, it is possible to reduce the penetration of the polishing slurry into the base layer 103.

The diameter of the base layer 103 may be a size that is in accordance with the diameter of the polishing layer 101 such that the difference between the diameter of the base layer 103 and the diameter of the polishing layer 101 falls within the range described above.

The thickness of the substrate layer 103 can be appropriately selected depending on the material of the workpiece 40 to be polished and the polishing characteristics required in the polishing process, and can be, for example, 0.5 mm or more, or 1.0 mm or more, and 2.0 mm or less, or 1.5 mm or less.

(Adhesive Layer)
The first adhesive layer 102 is a layer that bonds the polishing layer 101 and the base layer 103. The second adhesive layer 104 is a layer that bonds the polishing pad 100a and the base plate 150. The first adhesive layer 102 and the second adhesive layer 104 may be the same or different. The first adhesive layer 102 and the second adhesive layer 104 may be double-sided tape in which an adhesive is applied to both sides of a base material, or may be an adhesive layer consisting of only an adhesive.

Examples of substrates for double-sided tapes include polyimide resins, polyester resins, polyurethane resins, polyethylene resins (e.g., polyethylene terephthalate (PET)), polypropylene resins, cellulose resins, polyvinyl chloride resins, polyvinylidene chloride resins, polyvinyl alcohol resins, ethylene-vinyl acetate copolymer resins, polystyrene resins, polycarbonate resins, acrylic resins, and laminate resins of two or more of these.

The adhesive on the polishing layer 101 side of the double-sided tape and the adhesive layer used as the first adhesive layer 102 are preferably hot melt adhesives. The other adhesives may be hot melt adhesives or other types of adhesives (e.g., pressure-sensitive). Specifically, the other adhesives are the adhesive on the base layer 103 side of the double-sided tape used as the first adhesive layer 102, and the adhesive on the base layer 103 side of the double-sided tape, the adhesive on the base plate 150 side of the double-sided tape, and the adhesive layer used as the second adhesive layer 104.

Hot melt adhesives contain thermoplastic resins. Examples of thermoplastic resins include acrylic resins, ethylene vinyl acetate resins, olefin resins, synthetic rubber resins, polyamide resins, and polyester resins. Other types of adhesives include rubber adhesives, silicone adhesives, urethane adhesives, epoxy adhesives, and styrene-diene block copolymer adhesives. The adhesive does not have to be a single component, but may be a mixed type containing two or more components.

The diameter of the first adhesive layer 102 is not limited as long as it can bond the polishing layer 101 and the base layer 103, but is, for example, equal to or greater than the diameter of the base layer 103 and equal to or less than the diameter of the polishing layer 101. The diameter of the second adhesive layer 104 is not limited as long as it can bond the base layer 103 and the base plate 150, but is, for example, equal to or greater than the diameter of the base plate and equal to or less than the diameter of the base layer 103.

The thickness of the first adhesive layer 102 and the second adhesive layer 104 may be, for example, 0.01 mm or more, or 0.02 mm or more, and may be 0.5 mm or less, or 0.2 mm or less.

(Standard plate)
The surface plate 150 is a member that supports the polishing pad 100a and is included in the polishing apparatus. The diameter of the surface plate 150 may be a size that satisfies the diameter of the base layer 103 and that satisfies the above-mentioned range of the difference between the diameter of the base layer 103 and the diameter of the surface plate 150.

[Method of manufacturing the polishing pad]
As described above, the polishing pad 100a according to this embodiment is configured such that the diameter of the base layer 103 is smaller than the diameter of the polishing layer 101. Such a polishing pad 100a can be suitably manufactured using a special die described later. Hereinafter, a method for manufacturing the polishing pad 100a will be described with reference to FIGS. 3 to 5. FIG. 3 is a top view showing a die 50 used in the manufacturing method of the polishing pad 100a according to this embodiment. FIG. 4 is a cross-sectional view taken along the dashed line A-A' in FIG. 3. FIG. 5 is a schematic diagram showing each step of the manufacturing method of the polishing pad 100a according to this embodiment. The manufacturing method of the polishing pad 100a according to this embodiment includes a lamination step, a cutting step, and a peeling step.

(Lamination process)
In the lamination process, a laminated pad 110 is obtained in which the polishing sheet 111, the first adhesive sheet 112, the base sheet 113, and the second adhesive sheet 114 are laminated in this order (first layer in FIG. 5). As long as the laminated pad 110 in which the sheets are laminated in the above-mentioned order is obtained, the lamination method is not particularly limited. For example, each sheet may be laminated in order, or a sheet in which the polishing sheet 111 and the first adhesive sheet 112 are laminated may be superimposed on a sheet in which the base sheet 113 and the second adhesive sheet 114 are laminated. The size of the plane of the laminated pad 110 may be appropriately selected according to the shape and size of the plane of the desired polishing layer 101. For example, the planar shape of the laminated pad 110 may be a polygon (e.g., a rectangle), a circle, an ellipse, etc. In addition, as an example, when the laminated pad 110 is a square, the length of one side of the laminated pad 110 may be equal to or greater than the diameter of the desired polishing layer 101. A release sheet may be further laminated on the surface of second adhesive sheet 114 opposite to the surface bonded to base sheet 113. The manufacturing method of each sheet will be described later.

(Cutting process)
In the cutting step, the laminated pad 110 is cut using a die 50, and cuts 121 are made in the base sheet 113 and the second adhesive sheet 114 to obtain a cut pad 120 (second and third rows in FIG. 5).

First, the die 50 will be described with reference to Figures 3 and 4. As shown in Figures 3 and 4, the die 50 has a base 501, a cutting blade 502 provided on the base 501, a first cutting blade 503 (cutting blade), and two second cutting blades 504. The cutting blade 502 is a blade for cutting the laminated pad 110 into the shape of the polishing layer 101. The first cutting blade 503 is a blade for forming the base sheet 113 into the shape of the base layer 103.

The cutting blade 502 is designed so that the height h1 from the base 501 is equal to or greater than the thickness of the laminated pad 110. The first cutting blade 503 is disposed inside the cutting blade 502 when viewed from the cutting edge side of the cutting blade 502. The first cutting blade 503 is designed so that the height h2 from the base 501 is equal to or greater than the total thickness of the base sheet 113 and the second adhesive sheet 114. The difference h1-h2 between the height h1 of the cutting blade 502 and the height h2 of the first cutting blade 503 is designed to be equal to the thickness of the polishing sheet 111 or the total thickness of the polishing sheet 111 and the first adhesive sheet. When viewed from the cutting edge side of the cutting blade 502, the shapes of the cutting blade 502 and the first cutting blade 503 are circular. Specifically, the cutting blade 502 and the first cutting blade 503 are concentric circles. That is, the first cutting blade 503 is provided so that the distance from the cutting blade 502 is uniform. The height of the second cutting blade 504 from the base 501 is the same as the height h2 of the first cutting blade 503. The second cutting blade 504 is disposed between the cutting blade 502 and the first cutting blade 503.

The inner diameter d1 of the cutting blade 502 is set to the diameter of the desired polishing layer 101, and the inner diameter d2 of the first cutting blade 503 is set to the diameter of the desired base layer 103.

In the cutting process, the die 50 is inserted into the laminated pad 110 from the second adhesive sheet 114 side. Since the height of the cutting blade 502 is designed to be equal to or greater than the overall height of the laminated pad 110, the entire laminated pad 110 is cut by the cutting blade 502. On the other hand, the difference h1-h2 between the height h1 of the first cutting blade 503 and the height h2 of the cutting blade 502 is designed to be equal to the thickness of the polishing sheet 111 or the total thickness of the polishing sheet 111 and the first adhesive sheet 112, so that the first cutting blade 503 cuts only the base sheet 113 and the second adhesive sheet 114 in the laminated pad 110. In this way, the shape of the polishing layer 101 is cut out to obtain a cut pad 120 having a cut 121 in the shape of the base layer 103. Note that Figure 5 illustrates a case where the height h1 of the cutting blade 502 is the same as the overall thickness of the laminated pad 110, and the height h2 of the first cutting blade 503 is the same as the total thickness of the base sheet 113 and the second adhesive sheet 114 (the difference h1-h2 between the height h1 of the cutting blade 502 and the height h2 of the first cutting blade 503 is the same as the total thickness of the abrasive sheet 111 and the first adhesive sheet 112). If the height h1 of the cutting blade 502 is to be greater than the overall thickness of the laminated pad 110, the laminated pad 110 is placed on a workbench with the polished surface 111a, which is the surface of the laminated pad 110, facing down, and the die 50 is inserted into the laminated pad 110 from the second adhesive sheet 114 side until the cutting edge of the cutting blade 502 touches the workbench, thereby cutting the entire laminated pad 110 and making incisions 121 only in the base sheet 113 and the second adhesive sheet 114, as in FIG. 5 (not shown).

In addition, since the die 50 has not only the first cutting blade 503 but also the second cutting blade 504, not only the cut 121 but also two further cuts extending outward from the cut 121 can be made (not shown). Therefore, in the peeling process described below, it is easier to peel off the base sheet and the second adhesive sheet in the portion outside the cut 121.

By using a die 50 with this configuration, it is easier to manufacture a polishing pad in which each layer is arranged concentrically, compared to a method in which the polishing layer 101 and the base layer 103 are cut separately and then stacked.

When cutting a laminated pad in which a release sheet is further laminated on the surface of the second adhesive sheet 114 opposite to the adhesive surface with the base sheet 113, the height h2 of the first cutting blade 503 is set to a height that takes into consideration the thickness of the release sheet. Specifically, the height h2 of the first cutting blade 503 is designed to be equal to or greater than the total thickness of the base sheet 113, the second adhesive sheet 114, and the release sheet. In the cutting process, the laminated pad is cut by the cutting blade, and the base sheet 113, the second adhesive sheet 114, and the release sheet are cut by the first cutting blade and the second cutting blade to obtain a cut pad.

(Removal process)
In the peeling step, the base sheet and the second adhesive sheet on the outer side of the cut 121 in the cut pad 120 are peeled off to obtain the polishing pad 100a (fourth row in FIG. 5). The peeling method is not particularly limited. For example, the excess areas of the base sheet and the second adhesive sheet may be manually removed along the cuts made by the first cutting blade 503 and the second cutting blade 504.

When cutting a laminated pad with a release sheet laminated thereon, the peeling process involves peeling off the base sheet, the second adhesive sheet, and the release sheet that are on the outer side of the incision in the incision pad. In this way, a polishing pad is obtained in which the polishing layer 101, the first adhesive layer 102, the base layer 103, the second adhesive layer 104, and the release layer are laminated in this order.

When using a polishing pad that includes a release layer, the release layer can be removed and then the polishing pad from which the release layer has been removed can be attached to the platen.

[Manufacturing method of each sheet]
(Abrasive sheet)
The abrasive sheet 111 can be produced by commonly known manufacturing methods such as mold forming and slab forming. First, a block of polyurethane is formed by these manufacturing methods, and the block is sliced into a sheet to form the abrasive sheet 111 made of polyurethane resin. The shape of the abrasive surface 111a, which is the surface of the abrasive sheet 111, and the thickness of the abrasive sheet 111 are as described in (abrasive layer).

The polishing sheet 111 is formed by preparing a polyurethane resin curable composition containing a polyisocyanate compound and a polyol compound, and curing the polyurethane resin curable composition.

The polishing sheet 111 is made of foamed polyurethane resin. Foaming can be performed by dispersing a foaming agent containing hollow fine particles in the polyurethane resin. In this case, a polyurethane resin foaming curable composition containing a polyisocyanate compound, a polyol compound, and a foaming agent is prepared, and the polyurethane resin foaming curable composition is foamed and cured to form the sheet.

The polyurethane resin curable composition can be, for example, a two-liquid composition prepared by mixing liquid A containing a polyisocyanate compound with liquid B containing other components. Liquid B containing other components can be further divided into multiple liquids to form a composition consisting of three or more liquids mixed together.

The polyisocyanate compound may include a prepolymer prepared by reacting a polyisocyanate compound with a polyol compound, as is commonly used in the art. Prepolymers that contain unreacted isocyanate groups and are commonly used in the art can also be used in the present invention.

(Isocyanate component)
Examples of the isocyanate component include m-phenylene diisocyanate, p-phenylene diisocyanate, 2,6-tolylene diisocyanate (2,6-TDI), 2,4-tolylene 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'-biphenyl diisocyanate, and 3,3'-dimethyldiphenylmethane. 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, xylylene-1,4-diisothiocyanate, and ethylidine diisothiocyanate.

(Polyol Component)
Examples of the polyol component include diols such as ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, neopentyl glycol, pentanediol, 3-methyl-1,5-pentanediol, and 1,6-hexanediol; polyether polyols such as polytetramethylene glycol (PTMG), polyethylene glycol, and polypropylene glycol; polyester polyols such as a reaction product of ethylene glycol and adipic acid, and a reaction product of butylene glycol and adipic acid; polycarbonate polyols; and polycaprolactone polyols.

(Hardening agent)
The curing agent may be a polyamine-based curing agent. Examples of polyamines include diamines, such as alkylenediamines such as ethylenediamine, propylenediamine, and hexamethylenediamine; diamines having an aliphatic ring such as isophoronediamine and dicyclohexylmethane-4,4'-diamine; diamines having an aromatic ring such as 3,3'-dichloro-4,4'-diaminodiphenylmethane (also known as methylenebis-o-chloroaniline); and diamines having a hydroxyl group such as 2-hydroxyethylethylenediamine, 2-hydroxyethylpropylenediamine, di-2-hydroxyethylethylenediamine, di-2-hydroxyethylpropylenediamine, 2-hydroxypropylethylenediamine, and di-2-hydroxypropylethylenediamine, particularly hydroxyalkylalkylenediamines. Trifunctional triamine compounds and polyamine compounds having 4 or more functional groups may also be used.

The curing agent may be any other than a polyamine-based curing agent. Other curing agents include low molecular weight diols such as ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, neopentyl glycol, pentanediol, 3-methyl-1,5-pentanediol, and 1,6-hexanediol, as well as polyol curing agents such as high molecular weight polyol compounds such as poly(oxytetramethylene) glycol, polyethylene glycol, and polypropylene glycol.

(Amount of hardener used)
The physical properties of the polishing sheet 111 can also be adjusted by the chemical structure and amount of the curing agent used. The amount of the curing agent is preferably such that the equivalent ratio of the active hydrogen groups (amino groups or hydroxyl groups) present in the curing agent to the isocyanate groups present at the terminals of the prepolymer is 0.60 to 1.40, more preferably 0.70 to 1.20, and even more preferably 0.80 to 1.10.

(Air bubbles)
The polishing sheet 111 may have bubbles formed therein to improve the polishing characteristics. The bubbles can be formed by foaming using hollow fine particles, chemical foaming, mechanical foaming, or the like. The hollow fine particles refer to microspheres having voids, and include those having a spherical shape, an elliptical shape, and shapes similar thereto. Examples of hollow fine particles include those obtained by thermally expanding unfoamed heat-expandable microspheres consisting of an outer shell (polymer shell) made of a thermoplastic resin and a low-boiling point hydrocarbon contained in the outer shell. As disclosed in JP-A-57-137323, for example, thermoplastic resins such as acrylonitrile-vinylidene chloride copolymer, acrylonitrile-methyl methacrylate copolymer, and vinyl chloride-ethylene copolymer can be used as the polymer shell. Similarly, for example, isobutane, pentane, isopentane, and petroleum ether can be used as the low-boiling point hydrocarbon contained in the polymer shell.

(Base sheet)
The base sheet 113 can be manufactured by impregnating a nonwoven fabric with a resin. The type of nonwoven fabric, the type of resin, the density of the nonwoven fabric before and after resin impregnation, the adhesion rate of the resin to the nonwoven fabric, and the thickness of the base sheet 113 are the same as those described in the base layer.

(Adhesive sheet)
The material and thickness of the first adhesive sheet 112 and the second adhesive sheet 114 are the same as those described in the adhesive layer section.

[Method of manufacturing the polishing unit]
As described above, the polishing unit 10a according to this embodiment is configured such that the diameter of the base layer 103 is smaller than the diameter of the polishing layer 101 and larger than the platen 150. Such a polishing unit 10a can be manufactured by attaching the polishing pad 100a manufactured by the above-mentioned method for manufacturing a polishing pad to the platen 150 having a diameter smaller than the diameter of the base layer 103. In the manufacturing method of the polishing unit 10a, the polishing pad 100a may be attached to the platen 150 via a second adhesive layer so that the platen 150 is located inside the base layer 103 when viewed in plan from the platen 150 side.

[Embodiment 2]
Another embodiment of the present invention will be described below with reference to Fig. 6. For ease of explanation, the same reference numerals are given to members having the same functions as those described in the above embodiment, and the description thereof will not be repeated.

Figure 6 is a cross-sectional view showing the configuration of the polishing unit 10b according to this embodiment. As shown in Figure 6, the polishing unit 10b includes a polishing pad 100b and a platen 150. Furthermore, in addition to the configuration of the polishing pad 100a, the polishing pad 100b further includes a ring-shaped frame 105.

In this embodiment, the frame 105 surrounds the outer peripheral side surface 103a of the base layer 103 and the outer peripheral side surface 104a of the second adhesive layer 104. As a result, the frame 105 covers the outer peripheral side surface 103a of the base layer 103, the outer peripheral side surface 104a of the second adhesive layer 104, and the region 102b that is not in contact with the base layer 103 on the surface 102a of the first adhesive layer 102 on the base layer 103 side, i.e., the region 102b exposed from the base layer 103. By having such a frame 105, it is possible to more reliably prevent the polishing slurry from reaching the base layer 103 compared to when the polishing layer and the base layer have the same diameter. As a result, the penetration of the polishing slurry into the base layer 103 can be further reduced. By reducing the penetration of the polishing slurry into the base layer 103, it is possible to maintain the adhesion between the base layer 103 and the first adhesive layer 102, and between the base layer 103 and the second adhesive layer 104. In addition, the coating is designed so that no gaps are created between the surface being coated.

From the viewpoint of further reducing the penetration of the polishing slurry into the base layer 103, it is preferable that the frame 105 does not have any voids that connect from the outer peripheral side to the inner peripheral side. When the frame 105 is made of resin, the frame 105 is, for example, a resin molded body with closed cells in which the air bubbles formed in the resin are not connected, or a non-foamed resin molded body. From the viewpoint of making effective use of the material of the polishing layer 101, it is preferable that the material of the frame 105 is the same as the material of the polishing layer 101.

When the diameter of the surface plate 150 is equal to or less than the diameter of the base layer 103, the polishing of the material to be polished is usually performed at the center of the polishing surface 101a, and the material to be polished does not pass through the outer edge of the polishing surface 101a. Here, the center of the polishing surface 101a refers to the area of the polishing layer 101 that overlaps with the area inside the outer periphery of the surface plate 150 when viewed in plan from the polishing surface 101a side. In addition, the outer edge of the polishing surface 101a refers to the area of the polishing surface 101a that overlaps with the area outside the outer periphery of the surface plate 150 when viewed in plan from the polishing surface 101a side. In this way, when the diameter of the surface plate 150 is equal to or less than the diameter of the base layer 103, the frame 105 is located at a position that overlaps with the outer edge of the polishing surface 101a when viewed in plan from the polishing surface 101a side. As described above, since the material to be polished does not pass through the outer edge of the polishing surface 101a, it is not necessary to consider the cushioning properties of the frame 105. In addition, the height of the frame body 105 may be equal to or greater than the total thickness of the base layer 103 and the second adhesive layer 104. If the height of the frame body 105 is greater than the total thickness of the base layer 103 and the second adhesive layer 104, the frame body 105 acts as a guide when bonding the polishing pad 100a to the base plate 150, and can better prevent misalignment of the bonding. In this embodiment, the height of the frame body 105 is the same as the total thickness of the base layer 103 and the second adhesive layer 104.

The inner diameter of the frame body 105 is the same as the diameter of the base layer 103. The preferred inner diameter of the frame body 105 is as described above for the preferred diameter of the base layer 103.

The outer diameter of the frame 105 is preferably greater than the diameter of the base plate 150 and less than or equal to the diameter of the polishing layer 101. In this embodiment, the outer diameter of the frame 105 is the same as the diameter of the polishing layer 101.

[Embodiment 3]
Another embodiment of the present invention will be described below with reference to Fig. 7. For ease of explanation, the same reference numerals are given to members having the same functions as those described in the above embodiment, and the description thereof will not be repeated.

Figure 7 is a cross-sectional view showing the configuration of a polishing unit 10c according to this embodiment. As shown in Figure 7, the polishing unit 10c includes a polishing pad 100c and a platen 150. Furthermore, the polishing pad 100c further includes a seal portion 106 in addition to the configuration of the polishing pad 100a.

The sealing portion 106 is a protective member formed of resin that covers the outer peripheral side surface 103a of the base layer 103 in order to prevent the penetration of the slurry into the base layer 103. As shown in FIG. 1, the sealing portion 106 covers not only the outer peripheral side surface 103a of the base layer 103, but also the region 102b on the surface 102a of the first adhesive layer 102 that is not in contact with the base layer 103, i.e., the region 102b exposed from the base layer 103, and the outer peripheral side surface 104a of the second adhesive layer 104. This makes it possible to prevent the slurry from penetrating from the interface between the first adhesive layer 102 and the base layer 103 and the interface between the second adhesive layer 104 and the base layer 103. By reducing the penetration of the polishing slurry into the base layer 103, the adhesion between the base layer 103 and the first adhesive layer 102 and the adhesion between the base layer 103 and the second adhesive layer 104 can be maintained. In addition, the coating is designed so that no gaps are created between the surface being coated. When the diameter of the surface plate 150 is equal to or smaller than the diameter of the base layer 103, the seal portion 106 is positioned so as to overlap with the outer edge of the polishing surface 101a when viewed from above from the polishing surface 101a side. Therefore, when the diameter of the surface plate 150 is equal to or smaller than the diameter of the base layer 103, it is not necessary to consider the cushioning properties of the seal portion 106.

In a bending mode measurement of a dynamic viscoelasticity test measured at a frequency of 0.16 Hz, the loss modulus E"(S) of the seal portion 106 according to this embodiment at 40°C is preferably equal to or greater than the loss modulus E"(P) of the polishing layer 101 at 40°C. The loss modulus E"(S) of the seal portion 106 at 40°C is more preferably 1 to 10 times, and even more preferably 1.2 to 5 times, the loss modulus E"(P) of the polishing layer 101 at 40°C. In other words, E"(S)/E"(P) is more preferably 1 to 10, and even more preferably 1.2 to 5. As a specific numerical value, the loss modulus E"(S) of the seal portion 106 at 40°C is preferably 10 to 1000 MPa, and even more preferably 12 to 500 MPa.

In addition, in bending mode measurement of a dynamic viscoelasticity test performed at a frequency of 0.16 Hz, the storage modulus E'(S) of the seal portion 106 according to this embodiment at 40°C is preferably approximately equal to the storage modulus E'(P) of the polishing layer 101 at 40°C.
The storage modulus E'(S) of the seal portion 106 according to this embodiment at 40° C. is more preferably 0.1 to 10 times, and even more preferably 0.25 to 1 times, the storage modulus E'(P) of the polishing layer 101 at 40° C. In other words, E'(S)/E'(P) is more preferably 0.1 to 10, and even more preferably 0.25 to 1. As a specific numerical value, the storage modulus E'(S) of the seal portion 106 at 40° C. is preferably 10 to 5000 MPa, and even more preferably 25 to 500 MPa.

In addition, in bending mode measurement of a dynamic viscoelasticity test measured at a frequency of 0.16 Hz, the tan δ(S) of the seal portion 106 according to this embodiment at 40°C is preferably equal to or greater than the tan δ(P) of the polishing layer 101 at 40°C, and more preferably, tan δ(S)/tan δ(P) is 1 to 10, and even more preferably, tan δ(S)/tan δ(P) is 1.5 to 7. As a specific numerical value, the tan δ(S) of the seal portion 106 at 40°C is preferably 0.2 to 1.0, and more preferably 0.3 to 0.7.

The measured value in the bending mode measurement of the dynamic viscoelasticity test of the sealing portion 106 is within the above-mentioned range, i.e., the loss modulus E" (S) of the sealing portion 106 is equal to or greater than the storage modulus E" (P) of the polishing layer 101 and the storage modulus E' (S) of the sealing portion 106 is approximately equal to the storage modulus E' (P) of the polishing layer 101, so that cracks or breakage of the sealing portion 106 due to the force applied to the polishing pad 100 when the polishing pad 100 is bonded to the base plate 150 can be prevented. As a result, it is possible to more reliably prevent the slurry from passing through the sealing portion 106 and penetrating into the base layer 103.

In addition, the loss modulus E" (S), storage modulus E' (S), and tan δ (S) of the sealing portion 106 in the bending mode measurement of the dynamic viscoelasticity test are values measured using a test piece made of the same material as the sealing portion 106.The loss modulus E" (P), storage modulus E' (P), and tan δ (P) of the polishing layer 101 in the bending mode measurement of the dynamic viscoelasticity test are values measured using a test piece made of the same material as the polishing layer 101.

The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope of the claims. The technical scope of the present invention also includes embodiments obtained by appropriately combining the technical means disclosed in different embodiments.

An embodiment of the present invention will now be described.
Example 1
The polishing sheet, the first adhesive sheet, the base sheet, and the second adhesive sheet were laminated in this order to prepare a laminated pad of 815 mm square. As the polishing sheet, a polishing sheet (thickness 1.3 mm) in which balloons (hollow fine particles) were added to hard polyurethane resin (TDI-based prepolymer + aromatic diamine curing agent) was used. As the first adhesive sheet, a double-sided tape (thickness 0.1 mm) in which both sides of the PET base material were acrylic resin was used. As the base sheet, a base sheet (thickness 1.3 mm, density: 0.31 g/cm ^{3 , adhesion rate of polyurethane resin to nonwoven fabric: 100% by weight) in which nonwoven fabric (density: 0.16 g/cm 3 )} made of polyester fiber was impregnated with polyurethane resin was used. As the second adhesive sheet, a double-sided tape (thickness 0.1 mm) in which both sides of the PET base material were acrylic resin was used.

The obtained laminated pad was cut using a die as shown in Figures 3 and 4, and a cut was made in the base sheet and the second adhesive sheet to obtain a cut pad. The die had a cutting blade height h1 of 2.8 mm, a first cutting blade height h2 of 1.4 mm, and a second cutting blade height of 1.4 mm. The cutting blade had an inner diameter d1 of 762 mmφ, and the first cutting blade 503 had an inner diameter d2 of 758 mmφ. When viewed in a plan view from the cutting edge side of the cutting blade, the cutting blade and the first cutting blade were concentric circles.

Next, the base sheet and the second adhesive sheet on the outer side of the cut in the obtained cut pad were peeled off to obtain a polishing pad. The obtained polishing pad had a polishing layer (diameter 762 mmφ), a first adhesive layer (diameter 762 mmφ), a base layer (diameter 758 mmφ), and a second adhesive layer (diameter 758 mmφ) laminated in this order.

The polishing pad obtained by bonding the second adhesive layer to a 750 mmφ platen of the polishing device. When viewed from above from the platen side, the platen could be easily bonded inside the base layer. Specifically, the bonding operation was performed 30 times, and all 30 times the platen was easily bonded inside the base layer. The results of using the polishing device when the platen and polishing pad were bonded so that they were concentric when viewed from above are shown below.

(Comparative Example 1)
The laminated pad obtained in the same manner as in Example 1 was cut using a die having a diameter of 750 mm to obtain a polishing pad in which each layer had a diameter of 750 mm.

The resulting polishing pad was attached to a 750 mmφ platen of the same polishing apparatus as in Example 1 so that the platen and the polishing pad were concentric when viewed from above.

[Polishing test]
Wafers having thermal oxide films formed on their surfaces were polished using the polishing apparatuses prepared in Example 1 and Comparative Example 1. 85 wafers were polished using each of the polishing apparatuses prepared in Example 1 and Comparative Example 1. The polishing test conditions are shown below.

(Polishing conditions)
Polishing pressure: 3.5 psi
Polishing slurry: CLS-9044C (1:60) (Planar Solution) * _{No H2O2} Dresser: Diamond dresser, model number "A188" (3M)
Pad break-in conditions: 32N x 20 min, dresser rotation speed 72 rpm, polishing platen rotation speed 80 rpm, ultrapure water supply rate 500 mL/min Conditioning: Ex-situ, 32N, 2 scans, 16 sec Polishing: polishing platen rotation speed 85 rpm, polishing head rotation speed 86 rpm, polishing slurry flow rate 200 mL/min Polishing time: 5 min

After polishing was completed, the platen was rotated for 5 minutes to remove any moisture, and the polishing pad was then removed from the platen. The removed polishing pad was observed from the second adhesive layer side, and the degree of penetration of the polishing slurry into the base layer was compared.

In the polishing pad of Comparative Example 1, the polishing slurry penetrated into the base layer from the edge toward the center over the entire circumference by 3 cm. In contrast, the polishing pad of Example 1 was able to limit the penetration of the polishing slurry into the base layer to less than 1.5 cm from the edge toward the center. It was found that the polishing pad, in which the polishing layer is larger than the base layer, was able to reduce the penetration of the polishing slurry into the base layer more than the polishing pad of Comparative Example 1, in which the polishing layer and base layer are the same size.

The polishing unit according to one aspect of the present invention is used for polishing optical materials, semiconductor devices, hard disk substrates, etc., and is particularly suitable for polishing devices in which an oxide layer, a metal layer, etc. are formed on a semiconductor wafer.

REFERENCE SIGNS LIST 1 Polishing device 10a, 10b, 10c Polishing unit 20 Holding unit 30 Polishing slurry supply unit 40 Material to be polished 50 Punching die 100a, 100b, 100c Polishing pad 101 Polishing layer 102 First adhesive layer 103 Base layer 104 Second adhesive layer 105 Frame 106 Sealing unit 110 Laminated pad 111 Polishing sheet 112 First adhesive sheet 113 Base sheet 114 Second adhesive sheet 120 Cutting pad 150 Platen 501 Base 502 Cutting blade 503 First cutting blade (cutting blade)
504 Second cutting blade

Claims (7)

A polishing unit including a polishing pad and a platen,
The polishing pad is formed by laminating a polishing layer, a first adhesive layer, a base layer including a nonwoven fabric, and a second adhesive layer in this order;
the polishing pad is attached to the platen via the second adhesive layer,
a diameter of the base layer is smaller than a diameter of the polishing layer and is larger than a diameter of the platen;
The diameter of the second adhesive layer is equal to or smaller than the diameter of the base layer;
A polishing unit in which, when viewed in a plane from the base plate side, the base layer is positioned so as to be located inside the polishing layer, and the base plate is positioned so as to be located inside the base layer. The polishing unit according to claim 1, wherein the difference between the diameter of the base layer and the diameter of the platen is 1 mm or more and 20 mm or less. The polishing unit according to claim 1 or 2, wherein the difference between the diameter of the base layer and the diameter of the polishing layer is 1 mm or more and 10 mm or less. The polishing pad further has one of a ring-shaped frame and a seal portion surrounding an outer peripheral side surface of the base layer and an outer peripheral side surface of the second adhesive layer,
A polishing unit as described in any one of claims 1 to 3, wherein either the frame body or the sealing portion covers the outer peripheral side surface of the base material layer, the outer peripheral side surface of the second adhesive layer, and an area of the surface of the first adhesive layer facing the base material layer that is not in contact with the base material layer. A polishing device comprising a polishing unit according to any one of claims 1 to 4. A method for producing a polishing pad having a polishing layer and a base layer, comprising:
a lamination step of obtaining a laminated pad in which a polishing sheet, a first adhesive sheet, a base sheet including a nonwoven fabric, and a second adhesive sheet are laminated in this order;
a cutting step of inserting a die having a cutting blade on a base for cutting the laminated pad into the shape of the polishing layer and a cutting blade for cutting the laminated pad into the shape of the base material layer into the laminated pad from the second adhesive sheet side, and cutting the laminated pad;
the cutting blade is provided on the inside of the cutting blade, the height of the cutting blade is equal to or greater than the thickness of the laminated pad, the height of the cutting blade is equal to or greater than the total thickness of the base sheet and the second adhesive sheet, and the difference in height between the cutting blade and the cutting blade is equal to the thickness of the abrasive sheet or the total thickness of the abrasive sheet and the first adhesive sheet;
The method for manufacturing a polishing pad further includes a peeling step of peeling off the base sheet and the second adhesive sheet located outside the cut from the laminated pad cut to the shape of the polishing layer to obtain the polishing pad. The manufacturing method according to claim 6 , wherein the incision blades are provided at uniform distances from the cutting blades.

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