JP5567373B2 - Retaining material and method for producing retaining material - Google Patents

Description

  The present invention relates to a holding material and a method for manufacturing the holding material, and in particular, includes a plurality of sheet materials in which cells are formed with the same thickness having recesses, and an adhesive material for connecting the sheet materials. The present invention relates to a holding material and a method for manufacturing the holding material.

  Conventionally, materials (objects to be polished) such as semiconductor wafers and glass substrates for liquid crystal displays (LCDs) require high-precision flatness, and therefore polishing using a polishing pad has been performed. In the polishing of these objects to be polished, a single-side polishing machine that polishes the objects to be polished one by one may be used. In this single-side polishing machine, an object to be polished is held on a holding surface plate via a holding material, and is polished by a polishing pad mounted on the polishing surface plate. During polishing, a polishing liquid (slurry) containing abrasive particles is supplied while being circulated.

  In the polishing pad and holding material used in the polishing process, a soft material that is easily deformed by an external force is used. As a general polishing pad and holding material, a sheet material made of a soft resin having a foam structure formed by a wet coagulation method, an adhesive layer for mounting the sheet material on a polishing machine, and a function for protecting the adhesive layer And a peelable release material. Whereas the sheet material is a soft material, a hard material such as a resin film or paper is often used for the core material and release material of the adhesive layer. In such a polishing pad or holding material, the surface flatness is important in order to improve the flatness of the object to be polished. However, when the soft resin sheet material receives external force or due to its own weight, it is depressed (dented). There is a problem that it is easy to generate. That is, when the recess is generated, the flatness of the polishing pad or the like is impaired, so that the object to be polished may not be sufficiently flattened.

  On the other hand, for example, the size of glass substrates for LCDs has been increasing year by year for the purpose of improving LCD productivity, and large glass substrates having a side approaching 3 m have been used. The holding material used during polishing of a large glass substrate holds the glass substrate over the entire surface, so it is necessary to increase the size in accordance with the size change of the glass substrate. It's getting harder. In order to hold a large object to be polished, for example, a technique of holding a base plate via an adhesive material is disclosed (see Patent Document 1).

JP 2005-262327 A

  However, in the technique of Patent Document 1, although the retention can be satisfied by using an adhesive material, it requires work to remove the adhesive material adhering to the object to be polished after the polishing process, which is sufficient in terms of work efficiency. is not. On the other hand, it can respond to a large-sized to-be-polished object by connecting two holding | maintenance materials of the same kind. In order to facilitate handling and identification, if the holding material is connected in a stacked manner or wound, the connecting portion on the upper layer side comes into contact with the surface of the soft sheet material on the lower layer side. Depending on the thickness of the pressure-sensitive adhesive sheet, the connecting portion may have a step in the range of about 400 to 2000 μm, which is the thickness of the holding material. is there. Further, when the gap formed between the two holding members at the connection location becomes large, the impression of the protrusion becomes prominent due to the plastic deformation of the soft resin on the surface of the lower layer sheet material.

  In view of the above-described case, an object of the present invention is to provide a holding material and a method for manufacturing the holding material that can suppress the occurrence of recesses in the sheet material even when stacked or wound.

In order to solve the above-described problem, the first aspect of the present invention includes a plurality of sheet materials arranged in a manner that cells are formed in the same thickness having recesses and linear ends are adjacent to each other. A sheet-like adhesive material that is affixed to one surface side of an adjacent portion of the adjacent sheet material to connect the sheet material, and the adhesive material has a thickness of 100 μm or less, and The other side of the sheet material connected with the adhesive material forms a holding surface for holding the object to be polished, and the sheet material has a rectangular shape in which the length of the side intersecting the adjacent portion exceeds 1400 mm. It is a holding material characterized by being.

In the first aspect, the plurality of sheet materials arranged so that the linear end portions are adjacent to each other are in a rectangular shape in which the length of the side intersecting the adjacent portion exceeds 1400 mm, and on one surface side of the adjacent portion. Even if the adhesive material contacts the holding surface by arranging the connected sheet material in a laminated or wound form, the adhesive material is adhesively connected because it is connected with the adhered sheet-like adhesive material having a thickness of 100 μm or less. By limiting the thickness of the material, the shape of the sheet material can be easily restored, and the occurrence of depression due to the adhesive material with respect to each sheet material can be suppressed.

  1st aspect WHEREIN: It is preferable to connect so that the clearance gap formed in the adjacent part of a sheet | seat material may be 2 mm or less. The adhesive material may be affixed so as to be evenly positioned on each of the adjacent sheet materials. The adhesive material can have a thickness of 25 μm or more. The sheet material may be formed of a soft resin, and a sheet harder than the soft resin may be bonded to one side of the sheet material. The sheet material can be formed of a polyurethane resin by a wet coagulation method. The object to be polished can be a glass substrate for a liquid crystal display.

A second aspect of the present invention is a method for manufacturing a holding material according to the first aspect, wherein linear end portions of a plurality of sheet materials in which cells are formed with the same thickness having recesses are formed. A juxtaposition step of juxtaposing adjacent sheet materials by adhering a sheet-like adhesive material to one side of the linear adjacent portion of the sheet material juxtaposed in the juxtaposition step; wherein the provided adhesive for affixing at the connecting step with a thickness of less than 100 [mu] m, and the other surface of the sheet material which is connected by the adhesive material to form a holding surface for holding a workpiece The sheet material has a rectangular shape in which the length of the side intersecting the adjacent portion exceeds 1400 mm .

According to the present invention, the plurality of sheet materials arranged so that the linear end portions are adjacent to each other are in a rectangular shape in which the length of the side intersecting with the adjacent portion exceeds 1400 mm, and on one surface side of the adjacent portion. Even if the adhesive material contacts the holding surface by arranging the connected sheet material in a laminated or wound form, the adhesive material is adhesively connected because it is connected with the adhered sheet-like adhesive material having a thickness of 100 μm or less. By limiting the thickness of the material, it becomes easy to restore the shape of the sheet material, and it is possible to obtain an effect that the occurrence of the depression due to the adhesive material with respect to each sheet material can be suppressed.

It is sectional drawing which shows typically the connection pad to which the 2 holding sheet of embodiment which applied this invention was connected. It is sectional drawing which shows typically the one holding sheet | seat which comprises the connection pad of embodiment. It is a bottom view which shows typically the positional relationship of the holding | maintenance sheet | seat and connection tape which comprise a connection pad. It is process drawing which shows the outline of the connection method of two holding sheets.

  In the following, an embodiment in which the present invention is applied to an articulated pad in which two holding sheets for holding an object to be polished are articulated will be described with reference to the drawings.

<Configuration>
As shown in FIG. 1, in the connection pad 20 (holding material), the ends of two holding sheets 30 (sheet material) having the same thickness are adjacent to each other in order to hold a glass substrate or the like that tends to be enlarged. It is formed by being connected at a linear connecting portion 15 that is made to be. The holding sheet 30 is formed of a polyurethane resin-made urethane sheet 22 and a double-sided tape 26 to be attached to a polishing apparatus, and a surface of the double-sided tape 26 opposite to the urethane sheet 22 is covered with a release material 27. (Details will be described later). In the connection pad 20, the release material 27 disposed on one surface side of the two holding sheets 30 to be connected is connected to the connection portion 15 by the connection tape 18. At the connection location 15, the entire length of the linear boundary portion between the adjacent holding sheets 30 is covered with the connection tape 18. The other surface side of the connecting pad 20 forms a holding surface P for holding an object to be polished.

  In this example, the connecting tape 18 is coated with an adhesive on one side of the base material. The thickness of the connecting tape 18, that is, the total thickness T <b> 2 of the base material and the pressure-sensitive adhesive is adjusted in the range of 25 μm to 100 μm. As shown in FIG. 3, the connecting tape 18 is affixed so that the two holding sheets 30 (peeling material 27) are connected to each other with an equal width. The width of the connecting tape 18 can be adjusted in the range of 30 to 100 mm, but is adjusted to 50 mm in this example. That is, each 25 mm width of the connecting tape 18 is affixed to the two holding sheets 30.

  At the connection location 15, the two holding sheets 30 are linearly adjacent so as not to overlap. If the gap formed between the two holding sheets 30 becomes large, the surface flatness of the urethane sheet 22 of the holding sheet 30 may be impaired when the connecting pads 20 are arranged in a stacked or wound shape. For this reason, the gap between the two holding sheets 30 is adjusted to be 2 mm or less.

  As shown in FIG. 2, the holding sheet 30 has a urethane sheet 22 formed by a wet coagulation method with a polyurethane resin having a 100% modulus (tension when pulled twice) in a range of 2 to 30 MPa. . The urethane sheet 22 has a holding surface P that comes into contact with the workpiece when the workpiece is held on a surface plate. The thickness (length in the vertical direction in FIG. 2) of the urethane sheet 22 is uniform on the side opposite to the holding surface P of the urethane sheet 22 (the lower surface in FIG. 2). Buffed. For this reason, the holding surface P of the urethane sheet 22 is formed substantially flat. As shown in FIG. 1, the thickness T1 of the urethane sheet 22 is adjusted in the range of 200 to 1500 μm in this example. The thickness T1 can be adjusted when the urethane sheet 22 is produced by a wet coagulation method (details will be described later).

  On the urethane sheet 22, a skin layer 24 is formed on the holding surface P side. On the lower side of the skin layer 24 (inside the skin layer 24 of the urethane sheet 22), a rounded cone-shaped foam 23 (cell) having a length in the thickness direction of the urethane sheet 22 (cell). Is formed. The foam 23 is formed so that the size on the holding surface P side is smaller than that on the back surface side. That is, the diameter of the foam 23 is reduced on the holding surface P side than on the back surface side. The foam 23 has variations in the length of the urethane sheet 22 in the thickness direction. The polyurethane resin between the foams 23 is formed in a microporous shape in which fine pores (not shown) having a pore diameter smaller than that of the foam 23 are continuously formed. The skin layer 24, the foam 23, and the fine holes (not shown) communicate with each other in a mesh shape through communication holes (not shown). That is, the urethane sheet 22 has a continuous foam structure. Since the back surface side of the urethane sheet 22 is buffed, the foam 23 forms an opening on the surface on the back surface side. Further, the holding sheet 30 has the other side of the double-sided tape 26 having the release material 27 on one side (the lowermost side in FIG. 2) on the back side (the side that has been buffed). The double-sided tape 26 has a PET film substrate 26a, and adhesive layers 26b are formed on both surfaces of the substrate 26a. Although the paper 27 can be used as the release material 27, in this example, a hard resin film made of polyethylene terephthalate (hereinafter abbreviated as PET) is used. In this example, the base material 26a also has a function of supporting the holding sheet 30 and thus the connection pad 20.

<Manufacturing>
The connecting pad 20 is manufactured by connecting two holding sheets 30 formed by forming a polyurethane resin into a sheet shape by a wet coagulation method. In the production of the holding sheet 30 by the wet coagulation method, a sheet-like polyurethane formed by continuously applying a resin solution in which a polyurethane resin is dissolved in an organic solvent to a film forming substrate and coagulating the resin solution in an aqueous coagulation liquid. The resin is washed and dried, and then bonded to the double-sided tape 26. Specifically, the connecting pad 20 is manufactured as follows.

  The resin solution is prepared by mixing a polyurethane resin, a water-miscible organic solvent capable of dissolving the polyurethane resin, and an additive, and then degassing under reduced pressure. In this example, N, N-dimethylformamide (hereinafter abbreviated as DMF) is used as the organic solvent. As the polyurethane resin, a polyester resin, a polyether resin, a polycarbonate resin, or the like is selected and used. As additives, pigments, hydrophilic activators, hydrophobic activators, and the like can be used to control the size and amount (number) of foaming. The prepared resin solution is applied to a strip-shaped film forming substrate so as to have a uniform thickness. The coating thickness of the resin solution can be adjusted by a coating apparatus such as a knife coater used for coating on the film forming substrate. A flexible film, a nonwoven fabric, a woven fabric, or the like can be used for the film forming substrate. In this example, a PET film that does not have liquid permeability is used.

  The resin solution applied to the film forming substrate is guided to a coagulating liquid containing water as a main component, which is a poor solvent for the polyurethane resin. In the coagulation liquid, first, a skin layer 24 having a thickness of about several μm is formed on the surface side of the resin solution. Thereafter, the resin solution is solidified by the progress of substitution between the DMF in the resin solution and the coagulating liquid, and the sheet-like polyurethane resin is regenerated. Along with the replacement of the DMF with the coagulating liquid, the foam 23 is formed in the polyurethane resin inside the skin layer 24, and a continuous foam structure is formed. At this time, since the PET film of the film formation substrate does not permeate water, the solvent is removed on the skin layer 24 side, and the foam 23 having a larger film formation substrate side than the surface side is formed.

  The regenerated polyurethane resin (hereinafter referred to as film-forming resin) is peeled off from the film-forming substrate and washed in a cleaning liquid such as water to remove DMF remaining in the film-forming resin. After cleaning, the film forming resin is dried with a cylinder dryer or the like. The surface of the film-forming resin after drying is buffed on the surface opposite to the skin layer 24 of the film-forming resin so that the thickness is uniform, and the urethane sheet 22 is formed. The thickness T1 of the urethane sheet 22 is determined by the grinding removal amount by the buffing process and the application thickness of the resin solution described above. After the buffed surface side of the urethane sheet 22 and the other surface side of the double-sided tape 26 having the release material 27 attached to one surface side are bonded together via the adhesive layer 26b, the rectangular sheet has a desired size. The holding sheet 30 is produced by cutting.

(Joint)
When manufacturing the connecting pad 20 by connecting the two holding sheets 30, the following procedure is performed. That is, as shown in FIG. 4, a preparation step for preparing the connecting tape 18, a juxtaposition step for juxtaposing the two holding sheets 30 so as to be adjacent (a juxtaposition step), and the connecting tape 18 at the boundary portion between the adjacent holding sheets 30. The connecting pad 20 is manufactured through a connecting step (connecting step) for connecting and connecting. Hereinafter, it demonstrates in order of a process.

  In the preparation step, the connecting tape 18 is prepared by applying an adhesive to one side of the substrate. As the substrate, a flexible resin film, a nonwoven fabric, or the like can be used. In this example, a PET film is used. As the pressure-sensitive adhesive, any of acrylic, urethane, epoxy and the like can be used as long as it has adhesiveness to the release material 27 of the holding sheet 30. A pressure sensitive adhesive is used. It adjusts so that the total thickness T2 of a base material and an adhesive may become the range of 25-100 micrometers. In this example, an adhesive is applied to a substrate having a thickness of 25 μm with a thickness of 30 μm, and the thickness T2 is adjusted to 55 μm. Moreover, it cuts so that the width | variety of the connection tape 18 may be set to 50 mm. It is also possible to cover the surface of the pressure-sensitive adhesive opposite to the base material with release paper.

  In the juxtaposition process, the two holding sheets 30 are juxtaposed so as to be adjacent to each other. At this time, they are juxtaposed on the flat base so that the holding surface P is on the base and the release material 27 is on the top. Further, the two holding sheets 30 are adjusted and juxtaposed so that the two holding sheets 30 do not overlap and the gap between the two holding sheets 30 is 2 mm or less. Since the two holding sheets 30 have the same thickness, the holding surface P forms the same plane.

  In the connecting step, the connecting tape 18 is attached to a linear boundary portion where the release members 27 of the two holding sheets 30 arranged side by side are adjacent to each other. At this time, the connecting tape 18 is positioned and attached so as to be attached to the two holding sheets 30 with an equal width. Moreover, it affixes sequentially toward the other end side from the one end side of a boundary part so that air etc. may not bite into a bonding surface. Then, the connection pad 20 is completed by performing an inspection such as confirming that there is no adhesion of dirt or foreign matter. The connected pads 20 after manufacture are stacked in a laminated form or wound to form a cylindrical shape. In any form, handling such as storage and transportation becomes easy.

(Action etc.)
Next, an operation and the like of the connecting method of the connecting pad 20 and the holding pad 30 according to this embodiment will be described.

  Here, a conventional example will be described for easy understanding of the connection pad 20 of the present embodiment. The holding material used to hold the object to be polished at the time of polishing is formed of a soft resin having a recess, but in order to improve the flatness of the object to be polished, the flatness of the holding material itself is required. It is important to ensure. When such a holding material is stored and transported, it is arranged in a stacked or wound form in consideration of ease of handling and size reduction. For example, a single sheet having a rectangular side and a circular shape with a diameter of up to about 1000 mm is sufficient, but a rectangular shape with a side exceeding 1400 mm and a diameter exceeding 1400 mm are sufficient. In the case of a circular shape, if it is a laminated shape, it takes a lot of time to handle it, so it is arranged in a wound shape. When arranged in a wound shape, the weight is applied, and shaking and vibration (rolling and pitch) are also applied, which may impair the flatness of the retaining material having the recess. In addition, an object to be polished such as an LCD glass substrate has been enlarged, and for example, a rectangular object having a side of 3000 mm is manufactured. In polishing of such a large workpiece, it is necessary to increase the size of the holding material itself, but it is difficult to cope with one holding material, and this is dealt with by connecting two holding sheets. Has been. Since the holding sheet has a thickness of about 400 to 2000 μm, when the holding sheet is arranged in a laminated or wound form while being connected, a depression due to a step generated in the thickness range of the holding sheet may occur. That is, in the case of a laminated shape, the stepped portion of the holding sheet located on the upper side contacts the surface of the holding sheet located on the lower side, which may cause the holding surface for holding the workpiece to be recessed. There is. In the case of a wound shape, the same problem occurs on the inner peripheral side or the outer peripheral side. The present embodiment is a connection pad 20 that can solve these problems.

  In the connection pad 20 of the present embodiment, the two holding sheets 30 are connected by the connection tape 18. The connecting tape 18 is formed of a base material and an adhesive, and the total thickness T2 is adjusted in a range of 25 μm to 100 μm. For this reason, even if the connection pads 20 are arranged in a laminated or wound shape, the elasticity of the holding sheet 30 functions sufficiently due to the limited thickness T2. That is, even if a slight depression is generated in the urethane sheet 22, it can be restored by elasticity and kept flat. Thereby, generation | occurrence | production of the recess by the connection tape 18 with respect to the holding surface of the holding sheet 30 can be suppressed. If the thickness T2 of the connecting tape 18 is less than 25 μm, it will be difficult in terms of strength to hold the two holding sheets 30 together. On the other hand, when the thickness T2 exceeds 100 μm, the occurrence of depression is not sufficiently suppressed.

  Moreover, in the connection pad 20 of this embodiment, it connects so that the clearance gap between the adjacent boundary parts of the two holding sheets 30 may be 2 mm or less. Since this boundary portion is covered with the connecting tape 18, the connecting tape 18 comes into contact with the holding surface P when arranged in a laminated or wound form. When the gap exceeds 2 mm, the connecting tape 18 bends in the gap portion of the connecting portion and comes into contact with the holding surface P, thereby causing deformation of the protrusion on the holding surface P. In the connection pad 20, the size of the gap is limited, and the connection pad 20 is covered with the connection tape 18, so that the formation of protrusions on the holding surface P can be suppressed.

  Furthermore, in the connection pad 20 of this embodiment, even if it arrange | positions in lamination | stacking shape or winding shape, since generation | occurrence | production of a depression is suppressed, the flatness of the holding surface P is securable also at the time of storage or conveyance. As a result, the object to be polished is held by the flat holding surface P during the polishing process, so that the flatness of the object to be polished can be improved. Such a connection pad 20 can be suitably used as a holding material when polishing an object to be polished, that is, a glass substrate for LCD, or polishing the surface to a mirror surface.

  In the present embodiment, the example in which the two holding sheets 30 are connected by the connecting tape 18 has been described, but the present invention is not limited to this. For example, it is possible to connect three or more holding sheets 30 together. In the present embodiment, the example in which the connecting tape 18 is pasted so as to cover the entire length of the boundary portion between the adjacent holding sheets 30 is shown, but the present invention is not limited to this. It is only necessary that the two holding sheets 30 can be connected to each other by the connecting tape 18. For example, the holding sheet 30 may be partially attached without being attached to the entire linear connecting portion 15. Further, the connecting tape 18 is exemplified by a base material having a thickness of 25 μm and a pressure-sensitive adhesive of 30 μm and a total thickness T2 of 55 μm. However, the present invention is not limited to this, and the thickness T2 is 100 μm. The following is sufficient.

  In the present embodiment, an example in which the holding sheet 30 includes the polyurethane sheet 22 produced by the wet coagulation method and the double-sided tape 26 has been described. However, the present invention is not limited to this and has a concave property. However, it can be applied to a sheet material in which foaming is formed continuously. For example, the holding pad may have a resin sheet produced by a dry method, or may have only a resin sheet without having a double-sided tape. Further, the material of the holding sheet and the foam structure are not particularly limited.

  The present invention provides a holding material and a method for manufacturing the holding material that can suppress the occurrence of recesses in the sheet material even when stacked or wound, and contributes to the manufacture and sale of the holding material. Have potential.

P Holding surface 18 Connecting tape (adhesive)
20 articulated pad (holding material)
22 Urethane sheet 23 Foam (cell)
30 Holding sheet (sheet material)

Claims (8)

A plurality of sheet materials arranged such that cells are formed inside with the same thickness having indentation and linear ends are adjacent to each other;
A sheet-like adhesive material for adhering to the one side of the adjacent portion of the adjacent sheet material and connecting the sheet material;
With
The pressure-sensitive adhesive material has a thickness of 100 μm or less, and the other side of the sheet material connected by the pressure-sensitive adhesive material forms a holding surface for holding the object to be polished ,
The holding material, wherein the sheet material has a rectangular shape in which the length of the side intersecting the adjacent portion exceeds 1400 mm .   The holding material according to claim 1, wherein the sheet material is connected so that a gap formed in the adjacent portion is 2 mm or less.   The holding material according to claim 2, wherein the adhesive material is affixed so as to be evenly positioned on each of the adjacent sheet materials.   The holding material according to claim 3, wherein the adhesive material has a thickness of 25 μm or more.   The holding material according to claim 1, wherein the sheet material is formed of a soft resin, and a sheet harder than the soft resin is bonded to one side of the sheet material.   The holding material according to claim 5, wherein the sheet material is formed of a polyurethane resin by a wet coagulation method.   The holding material according to claim 6, wherein the object to be polished is a glass substrate for a liquid crystal display. It is a manufacturing method of the holding material according to claim 1,
A juxtaposition step of juxtaposing a plurality of sheet materials in which cells are formed with the same thickness having recesses so that linear ends are adjacent to each other;
A connecting step of connecting adjacent sheet materials by attaching a sheet-like adhesive material to one surface side in a linear adjacent portion of the sheet materials juxtaposed in the juxtaposition step;
Including
Wherein and adhesive material for affixing at connecting step comprises the following thickness 100 [mu] m, and, together with the other surface of the sheet material which are connected with the adhesive material to form a holding surface for holding a workpiece, the The manufacturing method characterized in that the sheet material has a rectangular shape in which the length of the side intersecting the adjacent portion exceeds 1400 mm .

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