JP2013208687A - Sheet for polishing pad, manufacturing method thereof, polishing pad, manufacturing method thereof, and polishing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sheet for a polishing pad capable of sufficiently suppressing occurrence of scratches on a polishing object.SOLUTION: A resin sheet for a polishing pad includes a resin sheet including a foam resin area with a plurality of foams, and a skin layer area integrally and inseparably formed on the foam resin area. In the sheet, the skin layer area is curved and/or bent in a thickness direction of the resin sheet, and thereby grooves are formed on a skin layer area side in the thickness direction of the resin sheet.

Description

  The present invention relates to a polishing pad sheet and a manufacturing method thereof, a polishing pad and a manufacturing method thereof, and a polishing method.

  Polishing pads used for polishing semiconductor devices and the like are roughly classified into hard and soft. In order to produce a hard polishing pad, a dry method in which a urethane prepolymer is molded while chain-extending is the mainstream. On the other hand, in order to produce a soft polishing pad, a urethane resin solution is molded in a coagulation bath and dried. Law is mainstream. In recent years, the flatness and uniformity (uniformity) of an object to be polished have been highly required, and the number of cases in which a soft polishing pad is used in a final polishing process or the like is increasing.

  So far, many soft polishing pads having grooves formed therein have been disclosed. By forming the groove on the polishing surface side of the polishing pad, it is possible to smoothly discharge the waste (polishing waste) generated by the movement of the slurry supplied during polishing and the friction of the polishing surface. As a method of forming such a groove, cutting and embossing are common. Since cutting can form fine grooves on the polishing pad, the pattern is not limited and versatility is high. Embossing is also frequently used because a wide variety of grooves can be formed just by changing the mold.

  Further, Patent Document 1 discloses a groove forming method using a method different from cutting and embossing. In this document, a urethane resin is applied to a surface of a shaped film having irregularities on the surface, a foamed sheet is formed by a wet foaming method, the foamed sheet is peeled off from the surface of the shaped film, and applied to the surface of the foamed sheet. A technique for forming a polished surface having a shape along the surface of a shaped film is disclosed.

JP 2002-331451 A

  However, among the above-described groove forming methods, in the cutting process, the inner surface such as the side wall surface and the bottom surface of the groove often has a crust-like rough surface due to the cutting of the hole portion and the open pores of the foamed foam, Cutting scraps are also generated in which the rough rough surface is peeled off during polishing. Due to the presence of the rough surface and the open pores on the inner surface of the groove, the slurry residue, polishing scraps and cutting waste are sandwiched between the scissors-shaped rough surface or easily enter the open pores. As a result, the residue of the slurry, polishing scraps and cutting scraps accumulate, and the occurrence of scratches (damage) on the object to be polished and uneven polishing are likely to occur. Further, such a polishing pad can easily swell due to the intrusion of the slurry liquid, lacks the form stability of the polishing pad, or easily peels off from the base material, and can withstand long-time polishing. There is a tendency not to be a thing.

  On the other hand, in the embossing, although the rough surface, open pores and cutting waste are not easily generated, a groove is formed by thermocompression bonding, so that the thermocompression surface (polishing surface) is hardened by heat, Cause scratches.

  Further, in the technique disclosed in Patent Document 1, the surface peeled off from the shaped film is used as it is as the polished surface, but a part of the resin remains on the shaped film at the time of peeling, and the polished surface is rough. There is a problem that the material to be polished is scratched and the foamed sheet is broken.

  The present invention has been made in view of the above circumstances, and provides a polishing pad sheet and a manufacturing method thereof, a polishing pad and a manufacturing method thereof, and a polishing method capable of sufficiently suppressing generation of scratches on an object to be polished. With the goal.

  As a result of intensive studies to achieve the above object, the inventors of the present invention can suppress the occurrence of scratches on the object to be polished if grooves are formed in the skin layer region by a method different from cutting or embossing. As a result, the present invention has been completed.

  That is, the present invention is a polishing pad sheet comprising a resin sheet including a foamed resin region having a plurality of bubbles and a skin layer region integrally formed on the foamed resin region, wherein the skin layer region is It is a sheet in which a groove is formed on the skin layer region side in the thickness direction of the resin sheet by being bent and / or bent in the thickness direction of the resin sheet. Moreover, the polishing pad of this invention is obtained from the said sheet | seat for polishing pads, and the grinding | polishing method of this invention has the process of grind | polishing a to-be-polished object using the said polishing pad.

  A method for producing a polishing pad sheet of the present invention includes a step of forming a resin sheet including a foamed resin region having a plurality of bubbles and a skin layer region inseparably formed on the foamed resin region, and a skin layer Forming the groove on the skin layer region side of the resin sheet by curving and / or bending the region in the thickness direction of the resin sheet. It has the process of forming the sheet | seat for polishing pads with the manufacturing method of the sheet | seat for polishing pads.

  According to the present invention, a groove can be formed without using cutting, embossing, and the method described in Patent Document 1, so that a rough surface with a crest-like shape and an open pore of foamed foam are generated by cutting the hole portion. It can be sufficiently suppressed that the surface (polished surface) subjected to thermocompression bonding is hardened by heat and that the resin remains in the shaped film and the polished surface is roughened. Rather, the skin layer region is formed by a resin being brought into contact with a coagulating liquid and coagulating and regenerating in a wet film forming method, and has excellent surface (polished surface) smoothness. Therefore, according to the present invention, it is possible to sufficiently suppress the generation of scratches on the object to be polished during polishing with the polishing pad.

  In the present invention, the surface of the skin layer region is preferably a polished surface. In addition, the foamed resin region has a plurality of island-shaped portions that are spaced apart from each other in the in-plane direction of the resin sheet, and the skin layer region is curved toward a space that exists between the plurality of island-shaped portions. It is preferable that the groove is formed by bending and / or bending. Further, a space surrounded by at least the back surface of the skin layer region and the side surface of the foamed resin region may be provided on the back side of the side wall of the groove, and the skin layer region forming the bottom surface of the groove has a tensile stress in the width direction of the groove. And / or the skin layer region forming the side wall surface of the groove may have a tensile stress in the depth direction of the groove.

  Moreover, even if the pressure-sensitive adhesive layer is further provided on the side of the foamed resin region in the thickness direction of the resin sheet, and the portion forming the bottom surface of the groove in the skin layer region and the foamed resin region are adhered to the pressure-sensitive adhesive layer It is preferable that a base material for supporting the resin sheet is further provided on the side of the foamed resin region opposite to the skin layer region in the thickness direction of the resin sheet. Furthermore, the resin sheet preferably contains 50% by mass or more of a polyurethane resin, preferably 100% modulus of the resin contained in the resin sheet is 4 to 50 MPa, and preferably has a Shore A hardness of 30 degrees or less. .

  A method for producing a polishing pad sheet of the present invention includes a step of forming a resin sheet including a foamed resin region having a plurality of bubbles and a skin layer region inseparably formed on the foamed resin region, and a skin layer Forming a groove on the side of the skin layer region of the resin sheet by curving and / or bending the region in the thickness direction of the resin sheet. The step of forming the resin sheet includes a step of applying a resin solution containing a resin and a solvent to the surface of the precursor sheet-forming substrate that has irregularities, and coagulating and regenerating the resin in the resin solution applied to the surface. Preferably, the method includes a step of forming a precursor sheet, a step of peeling the precursor sheet from the precursor sheet-forming substrate, and a step of removing the solvent from the peeled precursor sheet to obtain a resin sheet. In the step of forming the precursor sheet, the precursor sheet is preferably formed in a state in which it is attached to the precursor sheet-forming substrate on the surface opposite to the skin layer region. Moreover, it is preferable when it further has the process of sticking a resin sheet to an adhesive layer.

  The polishing pad of the present invention is obtained from the above-mentioned polishing pad sheet, and its production method includes a step of forming the above-mentioned polishing pad sheet. The polishing method of the present invention includes a step of polishing an object to be polished using the above-described polishing pad, and in this step, the object to be polished is preferably polished by chemical mechanical polishing.

  ADVANTAGE OF THE INVENTION According to this invention, the sheet | seat for polishing pads which can fully suppress generation | occurrence | production of the scratch in a to-be-polished object, its manufacturing method, a polishing pad, its manufacturing method, and a polishing method can be provided.

It is a schematic sectional drawing which shows an example of the sheet | seat for polishing pads of this invention. It is process drawing which shows an example of the manufacturing method of the sheet | seat for polishing pads of this invention. In an example of the manufacturing method of the sheet | seat for polishing pads of this invention, it is a schematic sectional drawing which shows the aspect in the 1 process. In an example of the manufacturing method of the sheet | seat for polishing pads of this invention, it is a schematic sectional drawing which shows the aspect in another 1 process. It is a cross-sectional photograph by the electron microscope of the sheet | seat for polishing pads of this invention.

  Hereinafter, a form for carrying out the present invention (hereinafter simply referred to as “the present embodiment”) will be described in detail with reference to the drawings as necessary. In the drawings, the same elements are denoted by the same reference numerals, and redundant description is omitted. Further, the positional relationship such as up, down, left and right is based on the positional relationship shown in the drawings unless otherwise specified.

  FIG. 1 is a schematic cross-sectional view showing an example of the polishing pad sheet of the present embodiment. The polishing pad sheet 100 of the present embodiment includes a base 110, a resin sheet 120, and an adhesive layer 130 sandwiched between them in order to adhere the resin sheet 120 on the base 110. The resin sheet 120 includes a foamed resin region 122 and a skin layer region 124 that is inseparably formed on the foamed resin region 122, and the skin layer region 124 is curved and / or bent in the thickness direction of the resin sheet 120. Thus, a groove 126 is formed on the skin layer region 124 side in the thickness direction of the resin sheet 120.

  The substrate 110 is in the form of a film, and supports the resin sheet 120 so that the polishing pad can be prevented from expanding and contracting or curving when polishing using the polishing pad prepared from the polishing pad sheet 100. Is for. The material may be used as a base material of a conventional polishing pad, and is not particularly limited. As a material, a flexible material is usually adopted, and examples thereof include polyethylene terephthalate (PET) and other polyesters. The thickness of the substrate may also be a thickness that is employed for a substrate of a conventional polishing pad, and is not particularly limited. The thickness is, for example, 0.1 to 5.0 mm.

  The pressure-sensitive adhesive layer 130 is used for sticking the resin sheet 120 on the substrate 110. The pressure-sensitive adhesive of the pressure-sensitive adhesive layer is not particularly limited, and may be a conventionally known pressure-sensitive type or heat-sensitive type. The pressure-sensitive adhesive layer 130 more securely fixes the foamed resin region 122 in the resin sheet 120 described later on the substrate 110, and also more reliably secures a portion where the groove 126 of the skin layer region 124 is formed on the substrate 110. Provided to fix. The thickness of the adhesive layer 130 is not specifically limited, For example, 5-100 micrometers may be sufficient.

  The resin sheet 120 includes, from the adhesive layer 130 side, a foamed resin region 122 having a plurality of bubbles, and a skin layer region 124 that is inseparably formed on the foamed resin region 122. The composition of the resin sheet 120 is not particularly limited as long as it is the composition containing the most resin (hereinafter referred to as “matrix resin”) serving as a matrix. For example, the resin sheet 120 is a matrix resin relative to the total amount thereof. 70-100 mass% may be included. The resin sheet 120 contains the matrix resin more preferably 70 to 90% by mass, and still more preferably 75 to 90% by mass with respect to the total amount.

  Examples of the matrix resin include polyurethane resin, polysulfone resin, and polyimide resin. These may be used alone or in combination of two or more, and may be used for a resin sheet portion of a conventional polishing pad. Among these, from the viewpoint of more effectively and reliably achieving the object of the present invention, the polyurethane resin is preferable, the polyurethane resin is preferably contained in an amount of 50% by mass or more, more preferably 80% by mass or more, It is more preferable to include 90% by mass or more, and it is particularly preferable to include 95% by mass or more.

  Examples of the polyurethane resin include a polyester-based polyurethane resin, a polyether-based polyurethane resin, and a polycarbonate-based polyurethane resin, and these are used singly or in combination of two or more. Among these, polyester polyurethane resins are preferred from the viewpoint of more effectively and reliably achieving the object of the present invention.

  The polyurethane resin may be synthesized by a conventional method, or a commercially available product may be obtained. Examples of commercially available products include Crisbon (trade name, manufactured by DIC Corporation), Samprene (trade name, manufactured by Sanyo Chemical Industries, Ltd.), and Resamine (trade name, manufactured by Dainichi Seika Kogyo Co., Ltd.).

  The polysulfone resin may be synthesized by a conventional method, or a commercially available product may be obtained. Examples of commercially available products include Udel (trade name manufactured by Solvay Advanced Polymers Co., Ltd.).

  The polyimide resin may be synthesized by a conventional method, or a commercially available product may be obtained. Examples of commercially available products include Aurum (trade name, manufactured by Mitsui Chemicals, Inc.).

  In addition to the matrix resin, the resin sheet 120 is made of a material usually used for a resin sheet provided in a polishing pad sheet, for example, one or more of pigments such as carbon black, hydrophilic additives and hydrophobic additives. May be included. These arbitrarily used materials may be used to control the size and number of bubbles 122a. Furthermore, various materials such as a solvent used in the manufacturing process of the resin sheet 120 may remain in the resin sheet 120 as long as the solution of the problem of the present invention is not hindered.

  The foamed resin region 122 of the resin sheet 120 has a plurality of island-shaped portions that are spaced apart from each other in the in-plane direction of the resin sheet 120, and the island-shaped portions are attached to the adhesive layer 130. Yes. The shape and size of the plurality of island-shaped portions depend on the pattern of the groove 126 described later in detail, and are not particularly limited, and may be the same or different from each other. Although the thickness of the foamed resin area | region 122 is not specifically limited, For example, it is 0.3-2.0 mm.

  In the foamed resin region 122, a plurality of bubbles 122a are formed in the matrix resin. The bubbles 122a have an action of absorbing an excessive pressing force of the object to be polished on the polishing pad when the object to be polished is polished by the polishing pad. The three-dimensional shape of the bubble 122a is not particularly limited, and may be any one or more of a substantially spherical shape, a vertically long shape (that is, long in the thickness direction of the resin sheet 120), and a spindle shape. From the viewpoint of (life), a vertically long cone shape and a spindle shape are preferable. Further, at least a part of the bubbles 122a may have an opening (not shown) that communicates with the main surface 120a via the skin layer region 124. Since the bubbles 122a have openings, it is possible to take in and hold the slurry used at the time of polishing by the chemical mechanical polishing method. The slurry held in the bubbles 122a is discharged from the opening when the object to be polished is pressed against the polishing pad, and is supplied between the object to be polished and the polishing pad. Since the bubbles 122a have openings as described above, the slurry can be supplied onto the polishing surface when an object to be polished is present, so that the slurry can be efficiently consumed. The formation of the bubbles 122a can be confirmed by observing a cross section appearing by cutting the resin sheet 120 in the thickness direction with a scanning electron microscope.

  The skin layer region 124 is inseparably formed with the foamed resin region 122. The skin layer region 124 is laminated on the island-shaped portion of the foamed resin region 122 and is directed toward a space existing between the plurality of island-shaped portions, that is, in the space in the thickness direction of the resin sheet 120. It is formed on the adhesive layer 130 side so as to bend and / or bend and its lower surface is attached to the adhesive layer 130. Thereby, a groove 126 is formed on the skin layer region 124 side in the thickness direction of the resin sheet 120, and a portion forming the bottom surface of the groove 126 is stuck to the pressure-sensitive adhesive layer 130.

  The skin layer region 124 forms a main surface 120a serving as a polishing surface of the polishing pad and the side wall surface and the bottom surface of the groove 126, and the thickness thereof is not particularly limited, but is several μm. The skin layer region 124 has a microporous structure in which many fine bubbles are formed in the matrix resin. Each of the fine bubbles usually has a smaller volume than the bubbles 122 a formed in the foamed resin region 122.

  The skin layer region 124 forms not only the main surface 120 a but also the side wall surface and the bottom surface of the groove 126, so that the groove is processed by cutting, embossing, and processing disclosed in Patent Document 1. Compared with the case where it is formed by, it becomes smoother. As a result, polishing scraps and abrasive grains in the slurry generated by the polishing process using the polishing pad are trapped by those surfaces in the groove 126, or the fluidity thereof is lowered due to friction with these surfaces. Since this can be effectively suppressed, it becomes possible to quickly discharge those polishing scraps and abrasive grains out of the system. Moreover, since such a groove | channel 126 is not formed by cutting, the crest-like rough surface by the cutting of the hole part which could be produced conventionally, and the open pore of foaming foam do not arise. Similarly, since such a groove 126 is not formed by embossing, it is possible to prevent hardening of the surface (polished surface) heat-compressed with embossing, which can be generated conventionally. Furthermore, according to the present embodiment, the skin layer region 124 constitutes a polished surface, but since such a polished surface is not formed by the method described in Patent Document 1, a part of the resin is polished on the shaped film. Excessive roughening of the surface is also suppressed. Therefore, according to the present invention, it is possible to sufficiently suppress the generation of scratches on the object to be polished during polishing with the polishing pad.

  The opening end 126a of the groove 126 has an arc shape in a cross section orthogonal to the length direction thereof. Thus, even if the object to be polished and the resin sheet 120 are rubbed during polishing, the opening end 126a is less likely to collapse, which is preferable. However, the shape of the groove is not limited to an arc shape.

  The shape of the cross section of the groove 126 orthogonal to the length direction is not particularly limited, and may be a trapezoidal shape with rounded corners as shown in FIG. 1, and may be an arc shape, a U shape, a V shape, or a rectangular shape. And other polygonal shapes. Further, the pattern in the in-plane direction of the main surface 120a of the resin sheet 120, that is, the groove pattern of the groove 126 is not particularly limited, and for example, a lattice shape, a radial shape, a concentric circle shape, a spiral shape, and two or more kinds of these It may be a combination. Further, the depth and width of the groove 126 and the interval (pitch) between the adjacent grooves 126 are not particularly limited. However, the mechanical strength of the polishing pad and the viewpoint of securing the area of the polishing surface in contact with the object to be polished, and The depth is preferably 0.1 to 1.8 mm and the width is 0.5 to 5.0 mm from the viewpoint of efficiently and reliably spreading the slurry over the entire surface of the polishing pad and discharging the slurry out of the system. The interval is preferably 2.0 to 20.0 mm. If the depth, width, and interval are within the above ranges, the polishing waste can be discharged more smoothly, and the generation of scratches can be further suppressed.

  In the present embodiment, a space 128 surrounded by at least the back surface 124 a of the skin layer region 124 and the side surface 122 b of the foamed resin region 122 is provided on the back side of the side wall 126 b of the groove 126 formed by the skin layer region 124. In FIG. 1, the space 128 is also surrounded by the top surface (upper surface) of the adhesive layer 130 together with the back surface 124a and the side surface 122b. By providing such a space 128, it is possible to suppress excessive pressing on the object to be polished (work) and further suppress damage to the object to be polished and / or the polishing pad.

  Further, in the skin layer region 124, the portion forming the bottom surface of the groove 126 may have tensile stress in the width direction of the groove 126 and / or the portion forming the side wall surface of the groove 126 is the groove 126. It may have a tensile stress in the depth direction. The matrix resin contained in such a skin layer region 124 is in a stretched state, and the side wall surface and / or the bottom surface, which is the surface thereof, is further smoothed, so that the fluidity of polishing scraps and abrasive grains in the slurry is reduced. It becomes possible to suppress this more effectively, and those polishing scraps and abrasive grains can be quickly discharged out of the system. Having a tensile stress means that, for example, when the skin layer region 124 of those portions is peeled from the adhesive layer 130, the skin layer region 124 contracts, and the degree of bending and / or bending is weakened upward. It can be confirmed by being raised. Alternatively, for example, when the side wall 126b of the groove 126 formed by the skin layer region 124 is cut, the cut portions can be confirmed to be contracted and separated from each other.

  The thickness of the resin sheet 120 is not particularly limited, but is preferably 0.3 to 2.1 mm (however, the groove 126 is ignored). When the thickness of the resin sheet is 0.3 mm or more, the life of the polishing pad can be more sufficiently guaranteed, and when the thickness is 2.1 mm or less, the appropriate hardness of the resin sheet 120 can be maintained, The sagging of the outer periphery of the polished article can be prevented more effectively.

From the viewpoint of more effectively and reliably achieving the operational effects of the above-described embodiment, the compression ratio of the resin sheet 120 is preferably 7 to 20%, and more preferably 12 to 20%. From the same viewpoint, the 100% modulus of the resin contained in the resin sheet 120 is preferably 4 to 50 MPa, and more preferably 7 to 30 MPa. Furthermore, from the same viewpoint, the Shore A hardness of the resin sheet is preferably 30 degrees or less, and more preferably 15 to 25 degrees. The compression rate is determined using a shopper type thickness measuring instrument (pressure surface: circle with a diameter of 1 cm) in accordance with Japanese Industrial Standards (JIS L 1021). Specifically, the thickness t1 after pressing for 30 seconds with an initial load is measured, and then the thickness t2 after standing for 5 minutes under the final pressure is measured. From these, the compression ratio is expressed by the following formula:
Compression rate (%) = (t1-t2) / t1 × 100
Calculate from At this time, the initial load is 100 g / cm ² and the final pressure is 1120 g / cm ² . The 100% modulus is a value obtained by dividing the load applied when the non-foamed resin sheet using the same material as the resin sheet 120 is stretched 100%, that is, twice the original length, by the cross-sectional area. is there. The Shore A hardness is measured in accordance with Japanese Industrial Standard (JIS K 6253) and is determined from the indentation depth of the push needle pressed against the surface of the test piece through a spring.

  Next, the manufacturing method of the polishing pad sheet of this embodiment will be described. In the manufacturing method of the polishing pad sheet of the present embodiment, a resin sheet 120 including a foamed resin region 122 having a plurality of bubbles 122a and a skin layer region 124 that is inseparably formed on the foamed resin region 122 is formed. A step (resin sheet forming step) and a step of forming the groove 126 on the skin layer region 124 side of the resin sheet 120 by bending and / or bending the skin layer region 124 in the thickness direction of the resin sheet 120 ( Groove forming step). As shown in FIG. 2, the manufacturing method of the polishing pad sheet of this embodiment is a process in which the resin sheet forming step prepares a resin solution containing a resin and a solvent based on a wet film-forming method (resin solution adjustment). Step), a step of applying the resin solution to the uneven surface of the precursor sheet forming substrate (film forming substrate) (application step), and coagulating and regenerating the resin in the resin solution applied to the surface Then, a step of forming a precursor sheet (coagulation regeneration step), a step of peeling the precursor sheet from the precursor sheet forming substrate (peeling step), and removing the solvent from the peeled precursor sheet, the resin You may have the process (solvent removal process) which obtains the sheet | seat 120 as needed, respectively. In the coagulation regeneration step, the precursor sheet is formed in a state of being attached to the precursor sheet forming base material on the surface opposite to the skin layer region 124. Furthermore, the manufacturing method of the sheet | seat for polishing pads of this embodiment performs the process (bonding process) of bonding the resin sheet 120 to the base material 110 through the adhesive layer 130 before the groove forming process as necessary. You may have. Hereinafter, each step will be described.

  First, in the resin solution preparation step, a matrix resin such as the above-described polyurethane resin, a solvent that can dissolve the matrix resin and is mixed with the coagulation liquid described below, and other resins that are included in the resin sheet 120 as necessary. The resin solution is prepared by mixing with the material and degassing under reduced pressure as necessary. Examples of the solvent include N, N-dimethylformamide (hereinafter abbreviated as DMF) and N, N-dimethylacetamide. From the viewpoint of securing the polishing ability of the resin sheet 120 and more sufficiently holding the slurry in the bubbles 122a, the resin solution has a viscosity measured at 25 ° C. using a B-type rotational viscometer in the range of 3 to 10 Pa · s. It is preferable and it is more preferable in the range of 3-7 Pa.s. From the viewpoint of obtaining a resin solution in such a numerical range of viscosity, and from the viewpoint of adjusting the coagulation speed described later, for example, the matrix resin is in the range of 10 to 30% by mass, more preferably in the range of 15 to 25% by mass. It may be dissolved in a solvent. Since the viscosity of the resin solution depends on the type and molecular weight of the matrix resin to be used, it is important to select the matrix resin, set the concentration, etc. in consideration of these comprehensively.

  FIG. 3 is a schematic cross-sectional view showing a state in which the resin solution is applied to the precursor sheet-forming substrate in the application step. In the coating step, the resin solution is preferably applied to the belt-shaped precursor sheet forming substrate 200 using a coating device such as a knife coater at room temperature to form the coating film 210. The precursor sheet-forming substrate 200 has an uneven shape on the application surface 200a to which the resin solution is applied, and the coating film 210 follows the uneven shape of the application surface 200a, and the coating film surface 210a is It is formed to be flat. The uneven shape of the application surface 200a is such that the resin solution filled in the concave groove portion 200b forms the foamed resin region 122, and is applied to the upper side of the groove portion 200b and the upper side of the convex protrusion portion 200c. The coated film 210 may have any shape that forms the skin layer region 124. Although the thickness of the resin solution applied at this time is not particularly limited, from the viewpoint of ensuring the polishing ability of the resin sheet 120 and more sufficiently holding the slurry in the bubbles 122a, from the bottom surface of the groove portion 200b. The thickness up to the coating surface 210a is preferably in the range of 0.3 to 2.1 mm, for example. The thickness from the upper surface of the protruding portion 200c to the coating film surface 210a is such that the depth of the groove 126 is such that the slurry can flow better while ensuring the smoothness of the surface of the skin layer region 124 more sufficiently. From a viewpoint of ensuring, it is preferable that it is the range of 0.3-2.0 mm.

  Examples of the material for the precursor sheet-forming substrate include resin films such as PET films, fabrics, and nonwoven fabrics. Among these, a resin film such as a PET film that hardly penetrates the resin solution is preferable.

  In the coagulation regeneration process, the coating film of the resin solution applied to the precursor sheet-forming substrate is continuously guided into a coagulating liquid mainly composed of a poor solvent for the matrix resin (for example, water in the case of polyurethane resin). To do. In order to adjust the regeneration rate of the matrix resin, an organic solvent such as a polar solvent other than the solvent in the resin solution may be added to the coagulation liquid. The temperature of the coagulation liquid is not particularly limited as long as the matrix resin can be coagulated. When the matrix resin is a polyurethane resin, it may be, for example, 5 to 80 ° C., preferably 15 to 20 ° C. It is. In the coagulating liquid, first, a film is formed at the interface between the coating film of the resin solution and the coagulating liquid, and innumerable fine bubbles constituting the skin layer region 124 are formed in the matrix resin immediately adjacent to the film. Thereafter, regeneration of the matrix resin preferably having an open-cell structure proceeds by a cooperative phenomenon of diffusion of the solvent contained in the resin solution into the coagulating liquid and penetration of the poor solvent into the matrix resin. At this time, if the precursor sheet-forming base material is difficult to permeate the coagulation liquid (for example, a PET film), the substitution of the solvent in the resin solution with the poor solvent occurs preferentially on the skin layer region 124 side. There is a tendency that larger bubbles 122a are formed on the foamed resin region 122 side than on the skin layer region 124 side.

  Next, in the peeling step, the precursor sheet is peeled from the precursor sheet-forming substrate. Since the matrix resin is regenerated on the precursor sheet forming substrate, the opening of the bubble 122a is formed on the back surface of the precursor sheet formed in contact with the surface of the precursor sheet forming substrate. Not.

  Next, in the solvent removal step, the solvent remaining in the precursor sheet obtained through the solidification regeneration step is removed to obtain the resin sheet 120. For removing the solvent, a conventionally known water washing treatment can be used. Moreover, you may dry the resin sheet 120 after removing a solvent as needed. For drying the resin sheet 120, for example, a hot air dryer or a cylinder dryer provided with a cylinder having a heat source inside can be used, but the drying method is not limited to this. When the cylinder dryer is used, the resin sheet 120 is dried by passing along the peripheral surface of the cylinder. Furthermore, you may wind up the obtained resin sheet 120 in roll shape. The resin sheet 120 obtained in this way includes a foamed resin region 122 and a skin layer region 124 that is inseparably formed on the foamed resin region 122. As shown in FIG. 124 is not bent and / or bent in the thickness direction of the resin sheet 120.

  FIG. 4 is a schematic cross-sectional view showing a state where the resin sheet 120 and the substrate 110 are bonded together in the bonding step. In the bonding step, the substrate 110 is bonded to the back surface 120b side of the resin sheet 120 after removing the solvent, that is, the side attached to the precursor sheet forming substrate. After sticking the adhesive layer 130 to the surface 110a side of the substrate 110 facing the resin sheet 120 by a conventional method, the back surface 120b side of the resin sheet 120 is further attached to the upper side of the adhesive layer 130, and the resin By pressing the sheet 120 and the base material 110 together, a laminate 300 in which the base material 110 and the resin sheet 120 are bonded to each other through the pressure-sensitive adhesive layer 130 can be obtained. The pressure-sensitive adhesive of the pressure-sensitive adhesive layer 130 may be conventionally known, and may be a pressure-sensitive type or a heat-sensitive type.

  Then, the groove forming step includes a space (between a plurality of island-shaped portions of the foamed resin region 122 on the lower side of the skin layer region 124 in the resin sheet 120 of the laminate 300 obtained as described above. The portion 124b in which the space is present is curved and / or bent toward the space, and the lower surface thereof is attached to the adhesive layer 130. Thereby, the polishing pad sheet 100 having the groove 126 shown in FIG. 1 can be obtained. Examples of the method of bending and / or bending include a method of pressing the portion 124b of the skin layer region 124 toward the pressure-sensitive adhesive layer 130 using a press machine or the like, but the method is not limited thereto. The cross-sectional shape of the groove 126 can be variously changed by adjusting the above-described pressing mode. For example, the portion to be attached to the pressure-sensitive adhesive layer 130 is appropriately adjusted, or the adhesive strength of the pressure-sensitive adhesive is adjusted. As a result, various cross-sectional shapes can be obtained.

  Further, the polishing pad sheet 100 shown in FIG. 1 has the space 128, but the shape of the space 128 can be variously changed by adjusting the above-described pressing mode. In addition, by sticking the entire lower surface of the portion 124b of the skin layer region 124 to the pressure-sensitive adhesive layer 130 as much as possible, the space 128 can be made extremely small or eliminated.

  The manufacturing method of the polishing pad of this embodiment includes the step of forming the polishing pad sheet 100 by the above-described manufacturing method of the polishing pad sheet. For example, the polishing pad of this embodiment can be obtained by cutting the polishing pad sheet 100 obtained as described above into a predetermined shape. Examples of the shape to be cut include, but are not limited to, a circular shape and a donut shape. Alternatively, the polishing pad sheet 100 may be used as it is as a polishing pad. Furthermore, you may provide another member, such as the below-mentioned adhesive layer and a peeling base material, on the opposite side to the resin sheet 120 with respect to the base material 110 of such a polishing pad. In either case, the main surface 120a side of the polishing pad sheet 100 is the polishing surface of the polishing pad. Preferably, an inspection such as confirming that there is no flaw, dirt, foreign matter or the like is performed until polishing is performed using the obtained polishing pad.

  The polishing method using the polishing pad of the present embodiment includes a step of polishing an object to be polished using the obtained polishing pad. One specific example will be described below. First, an object to be polished is held on a holding surface plate of a single-side polishing machine. Next, the polishing pad is mounted on the polishing surface plate disposed so as to face the holding surface plate. When mounting the polishing pad on the polishing surface plate, if the polishing pad further comprises an adhesive layer and a release substrate from the substrate side, the release substrate is removed to expose the adhesive layer, and then the exposed adhesive The agent layer is brought into contact with the polishing surface plate and pressed. In addition, when the polishing pad is not provided with the adhesive layer, it can also be mounted on the polishing surface plate after applying or attaching the adhesive to the substrate side. Then, a slurry containing abrasive grains (abrasive particles) is circulated and supplied between the object to be polished and the polishing pad, and the object to be polished is pressed against the polishing pad with a predetermined polishing pressure while being held on a polishing platen. By rotating the platen, the object to be polished is polished by chemical mechanical polishing.

  At this time, since the skin layer region 124 of the resin sheet 120 forms not only the polishing surface (main surface 120a) but also the side wall surface and the bottom surface of the groove 126, such a groove 126 has a crest-like shape that can be generated by cutting. It is difficult to have rough surfaces and open pores of foamed foam. Similarly, such a groove 126 is unlikely to have a polished surface hardened by thermocompression bonding that can be formed by embossing. Furthermore, the polishing pad of the present embodiment does not use the side attached to the precursor sheet forming substrate 200 as a polishing surface, but uses the opposite main surface 120a as a polishing surface. It is difficult for a portion of the resin to remain on the substrate 200 and the polished surface to become rough. Rather, since the skin layer region 124 is formed by the contact of the resin with the coagulation liquid and coagulation regeneration in the wet film formation method, the surface thereof is in a highly smooth state. Therefore, in the polishing process using the polishing pad of the present embodiment, it is difficult to generate cutting waste from the polishing pad, the hardness of the polishing surface is kept low, and cutting scraps, abrasive grains, polishing scraps, and the like are highly smooth. Since it is possible to quickly discharge from the groove 126 having the surface, it is possible to sufficiently suppress the generation of scratches on the object to be polished.

  The polishing pad of this embodiment is particularly suitably used for finish polishing of semiconductor devices such as magnetic disks, bare silicon, and glass substrates for liquid crystal displays. However, the use of the polishing pad of this embodiment is not limited to them.

  As mentioned above, although the form for implementing this invention was demonstrated, this invention is not limited to the said this embodiment. The present invention can be variously modified without departing from the gist thereof. For example, in another embodiment of the polishing pad sheet according to the present invention, the foamed resin region may be inseparably formed on the back side of the curved and / or bent skin layer region in addition to the above. In this case, the thickness of the foamed resin region formed on the back side of the curved and / or bent skin layer region is thinner than the thickness of the other foamed resin regions. Further, in this case, on the back side of the side wall of the groove, there may be a space surrounded by at least the back surface of the foamed resin region formed on the back side of the skin layer region and the side surface of the foamed resin region formed on the other part. Good.

  Further, in another embodiment of the method for manufacturing a polishing pad sheet according to the present invention, a grinding step may be further provided between the resin sheet forming step and the groove forming step, and the grinding step is performed after the groove forming step. You may have.

  In the former grinding process, the main surface (polishing surface) of the resin sheet on the skin layer region side and / or the back surface of the foamed resin region side is ground by buffing or slicing so that at least the skin layer region remains. To do. Since the thickness of the resin sheet can be made uniform by buffing or slicing, it is possible to further equalize the pressing force on the object to be polished and improve the flatness of the object to be polished.

  Further, in the latter grinding step, the flatness of the polishing surface in contact with the object to be polished can be further improved by grinding the polishing surface by buffing or slicing in the state where the grooves are formed. It is possible to further equalize the pressing force against the surface and improve the flatness of the object to be polished. In this case, at least a part of the skin layer region on the foamed resin region is ground, but the inner surface (side wall surface and bottom surface) of the groove is not ground, so the smoothness of the inner surface is maintained and polished. Since waste and abrasive grains can be quickly discharged, it is possible to suppress the occurrence of scratches on the object to be polished.

  Even if any of the above grinding steps is employed, it is not necessary to use cutting, embossing and the method disclosed in Patent Document 1 to form a groove, so that the generation of scratches on the object to be polished can be suppressed. .

  Further, the polishing pad sheet 100 of the present embodiment includes the pressure-sensitive adhesive layer 130 between the resin sheet 120 and the base 110, but instead of / in addition to the adhesive layer 130, the adhesive is based on the resin sheet 120. It may be applied to the material 110 side and / or the resin sheet 120 side of the base material 110. Examples of the adhesive include heat-sensitive adhesives such as acrylic and nitrile.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to these Examples.

Example 1
First, 50 parts by mass of a DMF solution of 30% polyester polyurethane resin (100% modulus: 23 MPa), 23 parts by mass of DMF for viscosity adjustment, 3 parts by mass of water, and a DMF dispersion of pigment carbon black (solid content) Carbon black is contained in an amount of 20% by mass with respect to the total amount.) 22 parts by mass was mixed to prepare a resin solution. The viscosity at 25 ° C. was measured with a B-type rotational viscometer (trade name “TVB-10 type” manufactured by Toki Sangyo Co., Ltd.) and found to be 7.0 Pa · s. Next, a PET film having an uneven shape on the coated surface was prepared as a precursor sheet-forming substrate. The uneven shape of the coated surface was a lattice pattern in which a plurality of concave portions having a square planar shape were arranged apart from each other. The said resin solution was apply | coated to the application surface of the base material for precursor sheet formation using the knife coater, and the coating film was obtained.

  Next, the obtained coating film was immersed in a room temperature coagulation bath made of water as a coagulation liquid, and the resin was coagulated and regenerated to obtain a precursor sheet. The precursor sheet is taken out from the coagulation bath, and the precursor sheet is peeled off from the precursor sheet forming substrate, and then immersed in a room temperature cleaning solution (desolvent bath) made of water to remove DMF and obtain a resin sheet. It was. Thereafter, the resin sheet was wound up while being dried. Next, on the PET film (thickness: 188 μm) as a base material, after applying a pressure sensitive adhesive using a gravure roll, on the back side of the resin sheet (side attached to the precursor sheet forming base material) The surface of the PET film coated with the pressure-sensitive adhesive was bonded with a press roll to obtain a laminate. Thereafter, the thin concave portion of the resin sheet was pressed so as to bend toward the PET film side, and not only the thick convex portion but also the concave portion was bonded to the PET film via an adhesive. The polishing pad sheet thus obtained was dried and wound up. The obtained polishing pad sheet has a lattice pattern in which a plurality of convex portions having a substantially square surface shape are arranged apart from each other. The depth of the groove, which is a concave portion, is about 0.4 mm, and the width is about 1 mm. The interval was 1 mm and the interval was about 13 mm. The width direction center vicinity of the obtained polishing pad sheet | seat was cut | disconnected along the length direction, and the appeared cross section was observed with the scanning electron microscope. The photograph is shown in FIG. From this photograph, it can be confirmed that the skin layer region formed on the plurality of spaced island-shaped foamed resin regions is curved in the thickness direction of the resin sheet to form a groove. It can also be confirmed that a space surrounded by the back surface of the skin layer region and the side surface of the foamed resin region is provided on the back side of the side wall of the groove.

  Shore A hardness was measured by the method described above. These results are shown in Table 1.

  The obtained polishing pad sheet was cut out so that the planar shape was a donut shape having an outer diameter of 64.0 cm and an inner diameter of 23.2 cm. The polishing pad was placed at a predetermined position of a polishing machine (trade name “9B-5P polishing machine” manufactured by Speed Fam Co., Ltd.), and a 95 mmφ hard disk aluminum substrate was polished as an object to be polished under the following conditions. did.

Polishing conditions and polishing speed (rotation speed): 30 rpm
Polishing pressure: 100 g / cm ²
・ Abrasive: Colloidal silica slurry (pH: 1.5)
・ Abrasive discharge rate: 100cc / min
・ Polishing time: 300 seconds

  It was visually confirmed whether or not scratches had occurred on the surface of the object to be polished after the polishing process. “A” indicates that no scratch is observed, and “B” indicates that the quality of the object to be polished is at a level that can be made in the product, although scratch is slightly recognized. The case where it was not possible was evaluated as "C". The results are shown in Table 1.

(Example 2)
A polishing pad sheet and a polishing pad were obtained in the same manner as in Example 1 except that the polyester-based polyurethane resin was changed to one having a 100% modulus of 8 MPa and the mixing ratio of each component was changed as shown in Table 1. Then, Shore A hardness was measured and the state of scratches generated by polishing was evaluated. The results are shown in Table 1.

(Comparative Example 1)
A resin solution was prepared in the same manner as in Example 2. Next, a PET film having an uneven surface on the coating surface was prepared as a precursor sheet-forming substrate, and the resin solution was applied thereto using the knife coater to obtain a coating film. Next, the obtained coating film was immersed in a room temperature coagulation bath made of water as a coagulation liquid, and the resin was coagulated and regenerated to obtain a precursor sheet. The precursor sheet was taken out from the coagulation bath, peeled off from the precursor sheet-forming substrate, immersed in a room temperature cleaning solution (desolvent bath) made of water, and DMF was removed to obtain a resin sheet. Thereafter, the resin sheet was wound up while being dried. Next, after applying the pressure-sensitive adhesive to the PET film (thickness: 188 μm) as a base material using a gravure roll, the surface on which the pressure-sensitive adhesive of the PET film is applied to the back side of the resin sheet by a press roll. The laminated body was obtained by bonding. Subsequently, the main surface of the resin sheet of the laminate was embossed. The processing conditions at that time were a processing pressure of 4.5 MPa, a processing (mold) temperature of 160 ° C., and a processing time of 180 seconds. The polishing pad sheet thus obtained has a lattice pattern in which a plurality of convex portions having a substantially square surface shape are arranged apart from each other, and the depth of the groove, which is a concave portion, is about 0.4 mm, and the width is about 1.0 mm. The spacing was about 3.0 mm. The obtained polishing pad sheet was dried and wound up.

  About the obtained sheet | seat for polishing pads, the polishing pad was produced similarly to Example 1, the Shore A hardness was measured, and the condition of the scratch which generate | occur | produces by grinding | polishing processing was evaluated. The results are shown in Table 1.

(Comparative Example 2)
A polishing pad sheet and a polishing pad were obtained in the same manner as in Comparative Example 1 except that grooves (cutting grooves) were formed using cutting instead of embossing. The conditions for the cutting process are as follows, and the obtained polishing pad sheet is a lattice pattern in which a plurality of convex portions having a substantially square surface shape are arranged apart from each other, and the depth of grooves that are concave portions Was about 0.4 mm, the width was about 1.0 mm, and the interval was about 5.0 mm.

  About the obtained sheet | seat for polishing pads and polishing pad, Shore A hardness was measured and the condition of the scratch which generate | occur | produces by polishing process was evaluated. The results are shown in Table 1.

(Comparative Example 3)
The same procedure as in Example 2 was performed until the resin sheet was wound up while being dried. Next, after applying the adhesive to the PET film (thickness: 188 μm) as a base material using a gravure roll, the main surface side of the resin sheet (attached to the precursor sheet forming base material) On the opposite side), the surface of the PET film coated with the adhesive was bonded with a press roll to obtain a polishing pad sheet. The polishing pad sheet thus obtained was dried and wound up. The obtained polishing pad sheet has a lattice pattern in which a plurality of convex portions having a substantially square surface shape are arranged apart from each other. The depth of the groove, which is a concave portion, is about 0.5 mm, and the width is about 1 mm. It was 0 mm and the interval was about 14 mm.

  About the obtained sheet | seat for polishing pads, the polishing pad was produced similarly to Example 1, the Shore A hardness was measured, and the condition of the scratch which generate | occur | produces by grinding | polishing processing was evaluated. The results are shown in Table 1.

  The polishing pad of the present invention is particularly suitably used for finish polishing of semiconductor devices such as magnetic disks, bare silicon, and glass substrates for liquid crystal displays, and has industrial applicability for those uses.

  DESCRIPTION OF SYMBOLS 100 ... Polishing pad sheet, 110 ... Base material, 120 ... Resin sheet, 122 ... Foamed resin region, 124 ... Skin layer region, 126 ... Groove, 128 ... Space, 130 ... Adhesive layer, 200 ... For precursor sheet formation Base material, 210 ... coating film, 300 ... laminate.

Claims (19)

A polishing pad sheet comprising a resin sheet comprising a foamed resin region having a plurality of bubbles, and a skin layer region integrally formed on the foamed resin region,
A sheet in which a groove is formed on the side of the skin layer region in the thickness direction of the resin sheet by bending and / or bending the skin layer region in the thickness direction of the resin sheet.   The sheet according to claim 1, wherein a surface of the skin layer region is a polished surface.   The foamed resin region has a plurality of island-shaped portions that are spaced apart from each other in the in-plane direction of the resin sheet, and the skin layer region faces a space that exists between the plurality of island-shaped portions. The sheet according to claim 1, wherein the groove is formed by bending and / or bending.   The sheet according to any one of claims 1 to 3, further comprising a space surrounded by at least a back surface of the skin layer region and a side surface of the foamed resin region on the back side of the side wall of the groove.   The skin layer region forming the bottom surface of the groove has a tensile stress in the width direction of the groove, and / or the skin layer region forming the side wall surface of the groove is a tensile stress in the depth direction of the groove. The sheet | seat of any one of Claims 1-4 which has these. Further comprising an adhesive layer on the side of the foamed resin region in the thickness direction of the resin sheet,
The sheet | seat of any one of Claims 1-5 in which the part which forms the bottom face of the said groove | channel in the said skin layer area | region, and the said foamed resin area | region are stuck on the said adhesive layer.   The sheet according to any one of claims 1 to 6, further comprising a base material for supporting the resin sheet on a side opposite to the skin layer region of the foamed resin region in the thickness direction of the resin sheet. .   The said resin sheet is a sheet | seat of any one of Claims 1-7 containing 50 mass% or more of polyurethane resins.   The sheet | seat of any one of Claims 1-8 whose 100% modulus of resin contained in the said resin sheet is 4-50 Mpa.   The sheet | seat of any one of Claims 1-9 whose Shore A hardness of the said resin sheet is 30 degrees or less.   The polishing pad obtained from the sheet | seat for polishing pads of any one of Claims 1-10. It is a manufacturing method of the sheet for polishing pads given in any 1 paragraph of Claims 1-10,
Forming a resin sheet including a foamed resin region having a plurality of bubbles, and a skin layer region integrally formed on the foamed resin region; and
Forming a groove on the skin layer region side of the resin sheet by curving and / or bending the skin layer region in the thickness direction of the resin sheet;
A manufacturing method comprising: The step of forming the resin sheet includes:
Applying a resin solution containing a resin and a solvent to the uneven surface of the precursor sheet-forming substrate;
A step of solidifying and regenerating the resin in the resin solution applied to the surface to form a precursor sheet;
Peeling the precursor sheet from the precursor sheet-forming substrate;
Removing the solvent from the peeled precursor sheet to obtain the resin sheet;
Have
In the step of forming the precursor sheet, the precursor sheet is formed in a state in which the precursor sheet is attached to the precursor sheet forming base material on a surface opposite to the skin layer region. The manufacturing method as described.   The manufacturing method according to claim 13, wherein the resin contains 50% by mass or more of a polyurethane resin.   The manufacturing method according to claim 12, wherein a surface of the skin layer region is a polished surface.   The manufacturing method of any one of Claims 12-15 which further has the process of sticking the said resin sheet to an adhesive layer.   The manufacturing method of a polishing pad which has the process of forming the sheet | seat for polishing pads with the manufacturing method of any one of Claims 12-16.   A polishing method comprising a step of polishing an object to be polished using the polishing pad according to claim 11.   The polishing method according to claim 18, wherein in the step, the object to be polished is polished by chemical mechanical polishing.