JP5421618B2 - Retainer - Google Patents

Description

  The present invention relates to a holder, and more particularly, to a holder including a resin sheet having a holding surface for holding an object to be polished and a frame member attached to the holding surface of the resin sheet.

  2. Description of the Related Art Conventionally, materials such as semiconductor devices and flat panel display (FPD) glass substrates (objects to be polished) are required to have high-precision flatness, and therefore polishing using a polishing pad has been performed. In general, a single-side polishing machine that polishes an object to be polished one side at a time is used for polishing the object to be polished. In this single-side polishing machine, an object to be polished is held on a holding surface plate and polished with a polishing pad mounted on the polishing surface plate. During polishing, a polishing liquid containing abrasive particles is supplied while being circulated.

  In general, in a polishing process using a single-side polishing machine, the holding surface plate is soft to suppress scratches (scratches) of the object to be polished that are caused by the object being in direct contact with a metal holding surface plate. A holding pad such as a cloth is attached. Although it is possible to avoid scratches and the like by attaching the holding pad, when the adhesiveness and static friction between the holding pad and the object to be polished are insufficient, that is, when the object holding ability of the holding pad is insufficient, Since the lateral shift of the object to be polished occurs during the polishing process, it becomes difficult to polish the object to be polished flatly. In order to suppress this lateral displacement, a holder (template assembly) is used in which a template (frame material) in which a through hole into which an object to be polished can be inserted is formed and a holding pad are bonded together with an adhesive. In the holder, the object to be polished is inserted into the through hole of the template to perform polishing, and the object to be polished is removed from the holder after the polishing process. In order to facilitate the insertion and removal of the object to be polished, a gap is formed between the object to be polished and the template.

  Usually, a resin sheet formed by a wet film forming method or a dry molding method is used for the holding pad. In the wet film forming method, a resin solution in which a resin is dissolved in a water-miscible organic solvent is applied to a sheet-shaped film forming substrate, and the resin is solidified and regenerated in an aqueous coagulating liquid. The resin sheet formed by the wet film forming method has a skin layer in which micropores are formed on the surface side over a thickness of about several μm. Since the surface of the skin layer is excellent in contact with the object to be polished, it is possible to hold the object to be polished by the surface tension of the liquid or the like by including a liquid such as water in the skin layer. On the other hand, in the dry molding method, a resin melt or prepolymer is cured and molded into a block shape with a mold or the like, and the obtained molded product is sliced into a sheet shape. Foam is formed inside the block-shaped molded product by mixing water, gas, or the like during the curing molding. For this reason, in the resin sheet obtained by slicing, an opening is formed on the surface. The object to be polished is held on the surface where the opening is formed.

  However, there is an increasing demand for flatness on the object to be polished. For example, in semiconductor devices, the flatness of the outer periphery of the material greatly depends on the yield (yield) of the product. Is desired. In order to improve such an end shape, various improvements in the polishing process have been attempted. For example, as a holder used when polishing one side of a silicon wafer, a holder technique in which a ring-shaped groove is formed on a holding pad inside a template is disclosed (see Patent Document 1). Moreover, when bonding a template and a holding pad, a technique is disclosed in which only the outer peripheral side of the template is bonded to reduce the influence of template bonding (see Patent Document 2).

JP 7-58066 A JP 2000-42910 A

  However, in the technique of Patent Document 1, although the influence of the template is suppressed by the ring-shaped groove formed in the holding pad, the holding pad becomes weak and the life (lifetime) is shortened by the groove processing of the holding pad. There are drawbacks. In the technique of Patent Document 2, only the outer peripheral side of the template is bonded to the holding pad. However, when only the outer peripheral side is bonded, considerable skill is required to cut the heat-sensitive adhesive material well. There is a problem that there is the above difficulty. Furthermore, in the heat-sensitive type paste material, it is softened (melted) by heating at the time of bonding and enters the holding pad side. For this reason, although it is not bonded to the holding pad on the inner peripheral side of the template, the surface on the holding pad side of the template and the surface of the holding pad are substantially in contact with each other, and the holding pad is distorted during polishing. When this occurs, a gap (space) sufficient to absorb the distortion is not formed. Accordingly, the distortion remains in the holding pad, and foreign matter such as wear debris of the holding pad is caught in the bonded portion, so that a flat holding surface cannot be secured. It is also a factor that impairs sex.

  This invention makes it a subject to provide the holder which can improve the edge part shape of a to-be-polished object, and can improve flatness in view of the said case.

In order to solve the above problems, the present invention provides a resin sheet having a flat holding surface for holding an object to be polished, and a penetration that is attached to the holding surface of the resin sheet and into which the object to be polished can be inserted. A frame member formed with at least one hole, and the frame member has a notch formed at an end portion on the holding surface side on the inner surface side of the through hole , and the resin sheet side This surface is attached to the holding surface at a position outside the inner surface with respect to the virtual center of the through hole .

In the present invention, a notch portion is formed in the frame material, and the surface of the frame material on the resin sheet side is attached to the holding surface at a position outside the inner surface with respect to the virtual center of the through hole. Since a gap is formed between the frame material and the resin sheet on the inner surface side, sinking of the resin sheet is ensured during polishing processing, and stress and strain applied to the outer periphery of the object to be polished are alleviated. It is possible to improve the flatness by improving the end shape.

In this case, the shape of the notch in the cross section in the thickness direction of the frame member is triangular or rectangular with respect to a virtual vertex where the extension line of the surface on the resin sheet side and the extension line of the inner surface of the through hole intersect. be able to. In this case, has a concave surface rather good also be further processed R with so as to have a convex shape of the notch is is R with a triangular shape, the shape of the notch is is R with rectangular Furthermore, but it may also have been processed R with as. The size of the gap L formed between the inner surface of the through hole and the outer edge of the workpiece is determined by the size of the interval L between the position of the inner edge of the portion where the frame material is adhered to the holding surface and the position of the inner surface of the through hole. More than that. At this time, the size of the interval L is preferably set to 1.0 mm or more. The size of the frame material at the inner surface position of the through hole in the gap formed between the notch and the holding surface can be at least 0.3 mm. In addition, the resin sheet can be formed of a polyurethane resin having a continuous foam structure formed by a wet film forming method and having a 100% modulus of 20 MPa or less.

According to the present invention, the notch portion is formed in the frame material, and the surface on the resin sheet side of the frame material is attached to the holding surface at a position outside the inner surface with respect to the virtual center of the through hole. Since a gap is formed between the frame material and the resin sheet on the inner surface side of the hole, sinking of the resin sheet is ensured during polishing and stress and strain applied to the outer periphery of the object to be polished are alleviated. It is possible to obtain an effect that the end shape of the polished article can be improved and the flatness can be improved.

It is sectional drawing which shows typically the holder of embodiment to which this invention is applied. It is sectional drawing which expands the sticking part of the template of a holder of embodiment, and a urethane sheet, and shows typically the positional relationship of a template and a to-be-polished object. FIG. 3 is a perspective view schematically showing the holder of the embodiment with a part of a template cut away. It is sectional drawing which expands and shows typically the sticking part of the template and urethane sheet of the holder of another aspect, (A) is a holder using the template whose notch part is a rectangular shape, (B) Is a holder using a template having a convex surface with a notched portion, and (C) is a holder using a template having a concave surface with a notched portion.

  Embodiments of a holder to which the present invention is applied will be described below with reference to the drawings.

(Constitution)
As shown in FIG. 1, the holder 10 of the present embodiment includes a urethane sheet 2 as a resin sheet and a template as a frame material that suppresses the object to be polished from causing lateral displacement and jumping out (limits the lateral displacement range). 4 is provided.

  The urethane sheet 2 is produced by a wet film forming method, and is formed of a polyurethane resin having a 100% modulus (tensile force when pulled twice) of 20 MPa or less. In order to make the urethane sheet 2 uniform in thickness, the surface on the skin layer side formed at the time of wet film formation is buffed. The skin layer is removed by this buffing process. The buffed surface constitutes a holding surface P for holding the object to be polished. Inside the urethane sheet 2, cells 3 having a triangular cross section rounded along the thickness direction (vertical direction in FIG. 1) are formed in a substantially uniformly dispersed state. The cell 3 is formed such that the hole diameter on the holding surface P side is smaller than the hole diameter on the surface opposite to the holding surface P (hereinafter referred to as the back surface). That is, the diameter of the cell 3 is reduced on the holding surface P side. On the holding surface P, since the skin layer is removed by the buffing process, an opening of the cell 3 is formed. In the polyurethane resin between the cells 3, foaming (not shown) having a pore diameter smaller than that of the cells 3 is formed. The cells 3 and the foam (not shown) are connected in a mesh pattern with communication holes (not shown). That is, the urethane sheet 2 has a continuous foam structure.

  The template 4 is made of a material mainly composed of a thermosetting resin such as an epoxy resin or a phenol resin, and is reinforced by containing a fiber material such as glass fiber in the thermosetting resin. In other words, the template 4 is made of fiber reinforced resin, and in this example, glass fiber reinforced epoxy resin is used. As shown in FIG. 3, the template 4 is formed so as to have an annular shape having the same outer diameter as that of the urethane sheet 2 and an inner diameter that allows insertion of an object to be polished. That is, a through hole 5 into which an object to be polished can be inserted is formed at the center of the template 4. The template 4 has a surface (adhesion surface) on the urethane sheet 2 side adhered to the holding surface P of the urethane sheet 2 via an annular adhesive film 6.

  As shown in FIG. 1, the template 4 has a notch 4 a formed at the end on the holding surface P side on the inner peripheral surface side. The notch 4 a is formed over the entire circumference on the inner peripheral surface side of the template 4. As shown in FIG. 2, the cutout portion 4 a has a triangular shape in the cross section in the thickness direction of the template 4. Since the cutout portion 4 a is formed, the template 4 is bonded to the holding surface P via the adhesive film 6 at the outer peripheral side of the template 4. In other words, between the template 4 and the urethane sheet 2, the position on the inner peripheral side of the adhesive film 6 (the position of the inner edge of the portion where the template 4 is adhered to the holding surface P) and the position of the inner surface of the template 4. The gap L is not attached and a gap is formed. In addition, the size of the through hole 5 formed in the template 4 is larger than the size of the object to be polished 30. That is, a gap G is formed between the inner surface of the through hole 5 and the outer edge of the workpiece 30. The size of the gap G is normally set to 0.5 to 1.0 mm. The size of the interval L is adjusted to be larger than the size of the gap G, and in this example, is adjusted to 1 mm or more. In the gap formed between the notch 4a and the holding surface P, the size of the gap H at the position of the inner surface of the through hole 5 is adjusted to at least 0.3 mm. The size of the gap L and the size of the gap H can be adjusted when the cutout portion 4a of the template 4 is formed.

  As the adhesive for the adhesive film 6, a thermoplastic adhesive (heat-sensitive adhesive) is used. Examples of the thermoplastic adhesive include various adhesives such as acrylic, nitrile, nitrile rubber, polyamide, polyurethane, and polyester. In consideration of bonding with the urethane sheet 2, it is preferable to use a polyurethane-based thermoplastic adhesive. One surface side of the adhesive film 6 is bonded to the bonding surface of the template 4, and the other surface side is bonded to the holding surface P of the urethane sheet 2. At this time, the adhesive of the adhesive film 6 is heated to such an extent that the adhesive is softened, and the template 4 and the urethane sheet 2 are pressed almost evenly, whereby the adhesive surface of the template 4 and the holding surface P of the urethane sheet 2 are bonded. It is adhered at almost regular intervals through the. In FIG. 1 and FIG. 2, the thickness of the adhesive film 6 is exaggerated for easy understanding (see FIG. 3).

  In addition, a double-sided tape 7 is bonded to the back side of the urethane sheet 2 via a support material (not shown) in order to attach the holder 10 to a holding surface plate of the polishing apparatus. The double-sided tape 7 has a substrate such as a film made of polyethylene terephthalate (hereinafter abbreviated as PET), and an adhesive layer such as an acrylic adhesive or a rubber adhesive is formed on both surfaces of the substrate. ing. Further, a film such as PET is used as the support material, and the urethane sheet 2 is bonded with the same adhesive as the double-sided tape 7. The double-sided tape 7 is bonded to a support material with an adhesive layer on one side of the substrate, and the adhesive layer on the other side is covered with a release paper 8.

(Manufacture of holders)
The holder 10 is manufactured by laminating the urethane sheet 2, the template 4, and the support material / double-sided tape 7 produced by a wet film forming method. In the wet film formation method, a preparation process for preparing a polyurethane resin solution, a coagulation regeneration process in which the polyurethane resin solution is continuously applied to a film formation substrate, and the polyurethane resin is coagulated and regenerated into a sheet form in an aqueous coagulation liquid; The urethane sheet 2 is manufactured through a washing / drying process for washing / drying the polyurethane resin and a buffing process for making the thickness uniform. Hereinafter, it demonstrates in order of a process.

  In the preparation step, N, N-dimethylformamide (hereinafter abbreviated as DMF), which is a water-miscible organic solvent capable of dissolving the polyurethane resin, and an additive are mixed to dissolve the polyurethane resin. For the polyurethane resin, a polyester-based, polyether-based, or polycarbonate-based resin having a 100% modulus of 20 MPa or less is used. For example, the polyurethane resin is dissolved in DMF so that the polyurethane resin becomes 30%. As additives, pigments such as carbon black for controlling the size and amount (number) of the cells 3, a hydrophilic activator for promoting cell formation, and a hydrophobic activator for stabilizing the coagulation regeneration of the polyurethane resin are used. Can do. The obtained solution is defoamed under reduced pressure to prepare a polyurethane resin solution.

  In the coagulation regeneration process, the polyurethane resin solution prepared in the preparation process is continuously applied to the film-forming substrate, and the polyurethane resin is coagulated and regenerated into a sheet in an aqueous coagulation liquid. The polyurethane resin solution is applied almost uniformly to the belt-shaped film-forming substrate at room temperature by a coating apparatus. In this example, a knife coater is used as the coating device. At this time, the application thickness (application amount) of the polyurethane resin solution is adjusted by adjusting the gap (clearance) between the knife coater and the film forming substrate. Although a flexible film, a nonwoven fabric, a woven fabric, or the like can be used as the film forming substrate, in this example, the film forming substrate is described as a PET film.

  The polyurethane resin solution applied to the film forming substrate is guided into a coagulating liquid containing water as a main component, which is a poor solvent for the polyurethane resin. In the coagulation liquid, first, micropores constituting a skin layer are formed over a thickness of about several μm on the surface side of the applied polyurethane resin solution. Thereafter, the polyurethane resin coagulates and regenerates into a sheet shape by the progress of substitution between the DMF in the polyurethane resin solution and the coagulation liquid. When DMF is desolvated from the polyurethane resin solution and DMF and the coagulating liquid are replaced, cells 3 and foam (not shown) are formed in the polyurethane resin inside the skin layer, and the cells 3 and foam (not shown) are reticulated. A communication hole (not shown) that communicates is formed. At this time, since the PET film of the film formation substrate does not allow water to permeate, desolvation occurs on the surface side (skin layer side) of the polyurethane resin solution, and cells 3 having a larger film formation substrate side than the surface side are formed. .

  In the washing / drying step, the solidified and regenerated band-like (long-form) polyurethane resin (hereinafter referred to as film-forming resin) is washed and then dried. That is, after the film-forming resin is peeled from the film-forming substrate, it is 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. The cylinder dryer includes a cylinder having a heat source therein. The film-forming resin is dried by passing along the peripheral surface of the cylinder. The film-forming resin after drying is rolled up.

  In the buffing process, the surface on the skin layer side of the film-forming resin dried in the cleaning / drying process is buffed. In the film-forming resin formed on the film-forming substrate, thickness variation occurs during wet film formation. After the film-forming substrate is peeled off, unevenness appears on the skin layer side by pressing a pressure welding jig having a flat surface on the back surface (the surface opposite to the skin layer). This unevenness is removed by buffing. In this example, since the continuously formed film-forming resin is strip-shaped, the surface on the skin layer side is continuously buffed while the pressure roller is pressed against the back surface. In the obtained urethane sheet 2, the thickness variation is reduced, the thickness is made uniform, and an opening is formed in the holding surface P.

  An adhesive layer on one side of the double-sided tape 7 is bonded to the back side of the buffed urethane sheet 2 via a support material. The release paper 8 is left on the other side of the double-sided tape 7. By cutting into a desired shape such as a circle or a square, a holding sheet in which the support material and the double-sided tape 7 are bonded to the back side of the urethane sheet 2 is obtained. Next, the template 4 is attached to the holding surface P of the holding sheet. The annular adhesive film 6 is formed by sticking the adhesive surface of the template 4 and one surface side of the adhesive film 6 larger than the template 4 and cutting the adhesive film 6 on the inner and outer peripheral sides of the template 4 respectively. . The other surface side of the adhesive film 6 and the holding surface P of the urethane sheet 2 are adhered. At this time, the template 4 and the holding sheet are pressed using a jig having a flat surface. Moreover, the adhesive force can be increased by heating the adhesive film 6 to such an extent that the adhesive is softened. Thereby, the urethane sheet 2 and the template 4 are stuck through the adhesive film 6 at a substantially constant interval. Then, the holder 10 is completed by performing an inspection such as confirming that the surface is free from scratches, dirt, foreign matter, and the like.

  When polishing the object to be polished, the object to be polished is held on the holding surface plate by the holding tool 10 mounted on the holding surface plate of the single-side polishing machine. A polishing pad for polishing a workpiece is attached to the polishing platen disposed so as to face the holding platen. When attaching the holder 10 to the holding surface plate, the release paper 8 is removed to expose the adhesive layer, and then the exposed adhesive layer is brought into contact with the holding surface plate and pressed. An appropriate amount of water is contained in the holding surface P, and an object to be polished is inserted into the through hole 5 of the template 4. The object to be polished is held through the holder 10 by pressing the object to be polished to the urethane sheet 2 side by the surface tension of the water that has entered the micropores or openings of the holding surface P and the elasticity of the polyurethane resin of the urethane sheet 2. Hold on the surface plate. During polishing processing, while circulating and supplying a polishing liquid (slurry) containing abrasive particles between the object to be polished and the polishing pad, by rotating the polishing platen or holding platen while applying pressure to the object to be polished, Polish the workpiece.

(Function)
Next, the operation and the like of the holder 10 of the present embodiment will be described.

  In the holder 10 of the present embodiment, a cutout portion 4 a is formed in the template 4. For this reason, since a gap is formed between the template 4 and the urethane sheet 2 on the inner surface side of the template 4, the sinking of the urethane sheet 2 is ensured also on the outer peripheral side of the object to be polished during polishing. Thereby, the stress applied to the peripheral portion (outer peripheral portion) of the object to be polished is relieved, so that the shape of the peripheral edge portion, that is, the end portion of the object to be polished can be improved, and the flatness can be improved. Therefore, by using the holder 10 for polishing a silicon wafer or the like, for example, the shape of the edge of the silicon wafer is improved, so that the yield and productivity of the product can be improved.

  Moreover, in this embodiment, since the notch part 4a is formed in the template 4, the surface (adhesion surface) of the template 4 on the urethane sheet 2 side is the virtual center of the through hole 5 (in this example, the urethane sheet 2). The same as the center.) Is attached to the urethane sheet 2 at a position outside the inner peripheral surface of the template 4. For this reason, the clearance gap between the template 4 and the urethane sheet 2 is securable on the inner peripheral surface side of the template 4.

  Furthermore, in this embodiment, the size of the interval L between the position of the inner peripheral side of the adhesive film 6 and the position of the inner peripheral surface of the template 4 is adjusted to 1 mm or more at the bonded portion of the template 4 and the urethane sheet 2. Has been. For this reason, when the object to be polished inserted into the through hole 5 moves during the polishing process, the distortion of the urethane sheet 2 generated at the peripheral edge of the object to be polished is stored in the portion of the interval L. As a result, the sinking of the urethane sheet 2 is less likely to be restricted at the peripheral edge of the object to be polished, and the end sagging of the object to be polished can be reduced. Moreover, when the size of the space | interval L shall be 1 mm or more, when sticking the template 4 and the adhesive film 6, the cutting | disconnection (cut) of the adhesive film 6 can be made easy. Since the distance L corresponds to the strain absorption space, the size thereof is not larger than the gap in which the movement of the object to be polished is allowed inside the template 4, that is, the size of the gap G (usually 0.5 to 1.0 mm). The distortion caused by the movement of the object to be polished is not completely absorbed. Moreover, as a space of the strain absorption space, the size of the gap H between the urethane sheet 2 (holding surface P) and the template 4 (notch portion 4a) at the position of the inner surface of the through hole 5 is secured to 0.3 mm or more. Thus, the distortion of the urethane sheet 2 can be absorbed. In other words, since the gap G is provided in order to improve the uniformity during the polishing process, the object to be polished is allowed to move within the template 4 by the gap G, and rotates (spins). , It also translates in the diameter direction (lateral direction). For this reason, distortion of the urethane sheet 2 due to the movement of the object to be polished occurs not only in the thickness direction but also in the lateral direction. In the holder 10 of the present embodiment, in addition to distortion in the thickness direction, distortion due to lateral movement can also be absorbed. Furthermore, if the space of the strain absorption space is secured by determining the size of the gap L and the gap H, even if minute fluff comes off or wear debris occurs on the surface of the urethane sheet 2 due to the movement of the object to be polished, The influence on the polishing process can be suppressed by entering the space.

  Furthermore, in this embodiment, by forming the notch 4a in the template 4, the end shape of the object to be polished can be improved. For this reason, compared with the case where groove processing is given to urethane sheet 2, urethane sheet 2 can be produced without applying a load. Thereby, since the characteristic of the urethane sheet 2 can be held for a long time during polishing, the life of the urethane sheet 2 and, by extension, the holder 10 can be improved.

  Furthermore, in this embodiment, the urethane sheet 2 is formed of a polyurethane resin having a modulus of 100% and 20 MPa or less. For this reason, since the holding surface P closely adheres to the shape of the object to be polished and exhibits followability, the object to be polished is held by pressing the object to be held against the holder 10 mounted on the holding surface plate. Can be improved. In this embodiment, a PET film is bonded to the back surface of the urethane sheet 2 as a support material. For this reason, since the flexible urethane sheet 2 is supported by the support material, it is possible to facilitate handling when the holder 10 is transported or attached to the polishing machine.

  Further, in the present embodiment, the urethane sheet 2 is formed by removing the skin layer formed during the wet film formation by the buffing process, and the holding surface P has an opening. For this reason, the object to be polished is held by the action of the surface tension of the liquid such as water formed in the holding surface P or the micropores and the elasticity of the resin of the urethane sheet 2. In holding the glass substrate for liquid crystal, the object to be polished is held through the surface of the skin layer formed during wet film formation. Adsorption due to the action of surface tension of water or the like is large, and movement of the object to be polished is limited at the time of polishing, which is preferable. On the other hand, in the urethane sheet 2 of the present embodiment, since the holes of the cells 3 are formed on the holding surface P, the surface tension is optimized, so that the object to be polished is a template during polishing. It becomes easy to rotate within the four through holes 5, and the processing spots due to the holder 10 are reduced, and the object to be polished can be easily removed after the polishing process.

  In the conventional holder, the template and the urethane sheet are bonded together with a thermoplastic adhesive. Normally, when polishing is performed by inserting an object to be polished into a through hole of a template, polishing pressure is applied to the object to be polished, so that the object to be polished sinks to the holder side, thereby improving the flatness of the processed surface. It has been. However, distortion may occur on the outer peripheral side of the object to be polished, that is, in the vicinity of the inner peripheral surface of the template of the urethane sheet due to the movement of the object to be polished during the polishing process. For this reason, since sinking is restricted on the outer peripheral side of the object to be polished, the processed surface is excessively polished, end sagging occurs in the object to be polished, and the end shape is impaired. When the end shape is impaired, for example, in the polishing process of a silicon wafer, it becomes difficult to obtain a product from the vicinity of the end portion, and yield and productivity are lowered. As the degree of flatness required for an object to be polished increases, it is desired to improve the finish to the vicinity of the outer periphery, that is, the end shape. The present embodiment is a holder that can solve these problems.

  In the present embodiment, the example in which the shape of the notch 4a in the cross section in the thickness direction of the template 4 is triangular is shown, but the present invention is not limited to this. For example, as shown in FIG. 4A, the shape of the notch 4a in the cross section in the thickness direction of the template 4 may be rectangular. Further, as shown in FIG. 4B, the notch 4a may be formed so as to have a convex surface with an R, and as shown in FIG. 4C, it has a concave surface with an R. It may be formed. In the present embodiment, the example in which the size of the interval L between the position on the inner peripheral side of the adhesive film 6 and the position of the inner surface of the template 4 is adjusted to 1 mm or more is shown, but the present invention is limited to this. Instead, the distance L may be larger than the gap G. Considering that the sinking of the object to be polished during the polishing process is not limited and that the distortion due to the lateral movement of the object to be polished is taken into consideration, the size of the interval L should be at least 1 mm. Is preferable, and it is more preferable to set it as 2 mm or more. In the present embodiment, an example in which the size of the gap H formed between the notch 4a and the holding surface P at the position of the inner surface of the through hole 5 is at least 0.3 mm is shown. Is not limited to this. The size of the gap H only needs to be secured as a strain absorption space, and may be adjusted in accordance with the interval L.

  Moreover, although glass fiber reinforced epoxy resin was illustrated as a material of the template 4 in this embodiment, this invention is not limited to this. Considering physical resistance at the time of polishing and chemical resistance to polishing liquid, fiber reinforced resin reinforced by fiber material such as glass fiber contained in thermosetting resin such as epoxy resin and phenol resin. It is preferable to use it. Of course, there are no restrictions on the resin or fiber material. Moreover, although the annular template 4 was illustrated in this embodiment, this invention is not limited to this. For example, a rectangular shape or an elliptical shape may be used in accordance with the shape of the object to be polished, and when a plurality of objects to be polished are simultaneously held by a large holding tool, a plurality of through holes may be formed in the template. .

  Furthermore, in the holder 10 of the present embodiment, a polyurethane resin having a 100% modulus of 20 MPa or less is exemplified as the material of the urethane sheet 2, but the present invention is not limited to this. For example, a polyester resin or the like may be used, and if the 100% modulus of the resin is set to 20 MPa or less, the obtained resin sheet is closely attached so as to match the shape of the object to be polished. Can be planned. Moreover, if a polyurethane resin is used, the urethane sheet 2 in which the uniform cells 3 are easily formed by a wet film forming method can be produced.

  Furthermore, in this embodiment, although the example which bonds the urethane sheet 2 to the adhesive surface of the template 4 via the adhesive film 6 was shown, this invention is not limited to this. For example, it is also possible to use a double-sided tape in which an adhesive is applied to both surfaces of a substrate such as a PET film. Furthermore, in this embodiment, the polyurethane-type thermoplastic adhesive was illustrated as an adhesive of the adhesive film 6, but this invention is not limited to this. For example, when a resin sheet such as polyethylene or polyester is used instead of the urethane sheet 2, a thermoplastic adhesive suitable for bonding with each resin may be used.

  Furthermore, in the present embodiment, an example in which the urethane sheet 2 is produced by a wet film forming method has been shown, but the present invention is not limited to this, and the urethane sheet 2 may be produced by a dry molding method. For example, in a dry molding method, a urethane prepolymer and a curing agent (chain extender) such as a polyol compound or a polyamine compound are mixed, and a cured molded product is sliced into a sheet to obtain a urethane sheet. it can.

  Moreover, in this embodiment, although the example which affixes the double-sided tape 7 on the back surface of the urethane sheet 2 via the support material of PET film was shown, this invention is not limited to this, For example, the urethane sheet 2 Another film, non-woven fabric, woven fabric or the like may be bonded between the tape and the double-sided tape 7. Of course, the urethane sheet 2 and the double-sided tape 7 may be bonded together without using a support material. Furthermore, in this embodiment, although the example which produces the urethane sheet 2 by buffing the surface by the side of the skin layer of film-forming resin was shown, this invention is not restrict | limited to this, The thickness of the urethane sheet 2 is shown. Should just be made uniform. For example, a slice process may be performed instead of the buff process, and the buff process or the slice process may not be performed depending on the type of the object to be polished.

  Hereinafter, the Example of the holder 10 manufactured according to this embodiment is described. In addition, it describes together about the holder of the comparative example manufactured for the comparison.

Example 1
In Example 1, a polyester MDI (diphenylmethane diisocyanate) polyurethane resin having a 100% modulus of 10 MPa was used as the polyurethane resin. To 100 parts of this DMF solution of polyurethane resin, 45 parts of DMF for viscosity adjustment, 40 parts of DMF dispersion containing 30% pigment carbon black, and 2 parts of hydrophobic activator were mixed to form a polyurethane resin solution. Was prepared. When applying the polyurethane resin solution, the clearance of the coating apparatus was set to 0.6 mm, and after the wet film formation, the skin layer side was buffed to obtain a urethane sheet 2 having a thickness of 0.4 mm. A through hole 5 having an inner diameter 1.0 mm larger than the outer diameter of the object to be polished is formed (that is, the size of the gap G is 1.0 mm), the interval L is 1.0 mm, and the cross section is The template 4 in which the notch 4a having a right isosceles triangle shape (the angle of the inclined surface with respect to the horizontal direction is 45 degrees) is bonded to the urethane sheet 2 via the adhesive film 6, and the holder 10 of the first embodiment is used. Manufactured. In this holder 10, since the adhesive film 6 is softened by heat and penetrates into the urethane sheet 2, the thickness of the adhesive film 6 cannot be measured. For this reason, the size of the gap H formed between the notch 4a and the holding surface P at the position of the inner surface of the through hole 5 substantially indicates the height of the notch 4a. Then, it becomes 1.0 mm.

(Comparative Example 1)
In Comparative Example 1, the holder of Comparative Example 1 was manufactured in the same manner as in Example 1 except that a template having no notch was used. That is, Comparative Example 1 is a conventional holder.

(Polishing performance evaluation)
Next, the silicon wafer was polished using the holders of Example 1 and Comparative Example 1 under the following conditions, and the polishing performance was evaluated by roll-off. Roll-off occurs when the peripheral portion of the object to be polished is excessively polished from the central portion, and is one of the measurement items for evaluating flatness. As a measuring method, for example, a two-dimensional profile image is obtained within a range of 2 mm in the radial direction from a position of 0.3 mm from the outer peripheral end to the center by an optical surface roughness meter. In the obtained two-dimensional profile image, when the radial direction is the X axis and the thickness direction is the Y axis, the values of the Y axis at the coordinate positions of X = 0.5 mm and X = 1.5 mm from the outer peripheral end are Y The leveling was corrected so that = 0, and the PV value between X = 0.5 and 1.5 mm of the two-dimensional profile image at this time was expressed as a roll-off value (index). A surface roughness measuring machine (manufactured by Zygo, model number New View 5022) was used for the roll-off measurement. The roll-off measurement results are shown in Table 1 below.
Polishing machine used: Fujikoshi Co., Ltd., MCP-150X
Rotation speed: (Surface plate) 100r / m, (Top ring) 75r / m
Polishing pressure: 330 g / cm ²
Swing width: 10mm (200mm from the swing center value)
Swing movement: 1 mm / min
Abrasive: manufactured by Nalco, product number 2350 (2350 stock solution: water = 1: 9 mixed solution used)
Object to be polished: 8 inch φ silicon wafer Polishing time: 20 minutes

  As shown in Table 1, in the polishing process of the silicon wafer using the conventional holder of Comparative Example 1, the roll-off value was 1.0. On the other hand, in the polishing process of the silicon wafer using the holder 10 of Example 1, the roll-off value was 0.9, and almost the same performance as Comparative Example 1 was confirmed. Even if the notch 4a was formed in the template 4, the initial end shape was hardly affected. Regarding the determination of the life of the holder in the actual polishing process, there is a problem of the adsorption performance, but it is becoming more and more likely that the deviation from the end shape standard affects the life end. Therefore, in the holder 10 to which the template 4 in which the notch portion 4a is formed is attached, the improvement in life can be expected by forming the notch in the end portion on the holding surface P side on the inner peripheral surface side of the template 4. it can.

  Since the present invention provides a holder that can improve the end shape of the object to be polished and improve the flatness, it contributes to the manufacture and sale of the holder, and thus has industrial applicability. .

P Holding surface 2 Urethane sheet (resin sheet)
4 Template (frame material)
4a Notch part 5 Through-hole 10 Holder

Claims (8)

A resin sheet having a flat holding surface for holding an object to be polished;
A frame member attached to the holding surface of the resin sheet and having a through hole into which the object to be polished can be inserted is formed in at least one place;
With
The frame member has a notch formed at the end of the holding surface on the inner surface side of the through hole, and the surface on the resin sheet side is outside the inner surface with respect to the virtual center of the through hole. A holder characterized by being attached to the holding surface at a position . The frame member has a triangular or rectangular shape with respect to a virtual vertex at which the shape of the cutout portion in the cross section in the thickness direction intersects the extension line of the surface on the resin sheet side and the extension line of the inner surface of the through hole. The holder according to claim 1 , wherein the holder is provided. The holder according to claim 2 , wherein the cutout portion has a triangular shape and is further subjected to an R process so as to have an R-shaped convex surface . The holder according to claim 2 , wherein the cutout portion has a rectangular shape and is further subjected to R processing so as to have an R-attached concave surface . In the frame material, the size of the interval L between the position of the inner edge of the portion adhered to the holding surface and the position of the inner surface of the through hole is formed between the inner surface of the through hole and the outer edge of the object to be polished. The holder according to claim 1 , wherein the holder is larger than a size of the gap to be formed.   The holder according to claim 5, wherein the distance L is 1.0 mm or more.   7. The frame material according to claim 6, wherein a size of a gap formed between the notch and the holding surface at a position of an inner surface of the through hole is at least 0.3 mm. Retaining tool.   The holder according to claim 1, wherein the resin sheet has a continuous foam structure formed by a wet film forming method, and is formed of a polyurethane resin having a 100% modulus of 20 MPa or less.

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