JP4305656B2 - Adsorption fixing sheet and manufacturing method thereof - Google Patents

Description

  The present invention relates to a suction fixing sheet including a porous sheet and a method for manufacturing the same, and in particular, suction fixing for suction conveyance, vacuum suction fixing, and the like in the manufacture of glass plates for liquid crystals, semiconductor wafers or multilayer ceramic capacitors. The present invention relates to a sheet and a manufacturing method thereof.

  For example, in the case of an electronic component such as a ceramic capacitor configured by laminating dielectric sheets, the dielectric sheet is sucked and fixed and conveyed, and as one of the members to be further laminated, a plastic porous as a sheet for adsorbing and fixing conveyance A sheet is used.

  As this plastic porous sheet, a porous sheet made of ultra high molecular weight polyethylene (hereinafter referred to as “UHMWPE”) having an average molecular weight of 500,000 or more is used in consideration of air permeability, rigidity, cushioning properties and the like. Proposed.

  A porous sheet made of UHMWPE is generally manufactured, for example, by filling a mold with UHMWPE and sintering. According to this method, a porous sheet 11 having a surface state in which spherical or substantially spherical UHMWPE particles 12 are aligned as shown in FIG. 2 is obtained. In this porous sheet 11, the distance between the particle tops is, for example, several hundred μm.

  On the other hand, multilayer ceramic capacitors have recently been stacked with high density, and dielectric sheets have also been thinned. Along with this, a technique for laminating dielectric sheets of about several μm is indispensable. However, the thinning of the dielectric sheet causes a decrease in its rigidity, making its handling very difficult. For example, when the dielectric sheet is sucked and fixed to the porous sheet, there is a phenomenon that the dielectric sheet is embedded in the holes of the porous sheet due to a decrease in rigidity. As a result, the dielectric sheet is deformed, and defects such as scratches are generated on the dielectric sheet, thereby causing various defects.

  For example, Patent Document 1 to Patent Document 4 propose a very characteristic manufacturing method regarding the manufacturing method of the suction-fixed conveying sheet. According to this method, as shown in FIG. 3, a porous sheet 13 having a smoother surface 14 (with an irregularity interval of 30 μm, for example) is obtained as compared with the porous sheet 11 produced by the conventional method.

  In the suction-fixed conveying sheet obtained by the conventional method, the dielectric sheet is attracted and fixed by point contact microscopically, but in the manufacturing method, it is sucked and fixed by surface contact. Therefore, this manufacturing method can reduce the deformation of the dielectric sheet and the occurrence of defects such as scratches on the dielectric sheet, and is an extremely effective means for the thinned dielectric sheet.

  Furthermore, in order to further smooth the surface of the suction-fixed transport sheet, a method has been proposed in which the suction-fixed transport sheet is laminated on a plastic film having a smooth surface, and this is heated and pressurized (for example, a patent) Reference 5). According to this method, as shown in FIG. 4, a suction fixing and conveying sheet 15 having a smoother surface 16 can be obtained.

However, if the surface of the adsorption / fixing / conveying sheet is made smooth, the contact area between the adsorption / fixing / conveying sheet and the dielectric sheet becomes too large, and the peelability is lowered. As a result, there has been a problem that the dielectric sheet is scratched when the dielectric sheet is peeled off from the suction-fixed conveying sheet.
JP-B-5-66855 JP-A-8-169971 JP-A-8-258198 Japanese Patent Laid-Open No. 9-22935 JP 2001-28390 A

  The present invention has been made in view of the above-mentioned conventional problems, and its purpose is to perform adsorption that can sufficiently cope with thinning of a dielectric sheet or the like as an adsorbed member without changing any conventional process equipment. It is providing the fixing sheet and its manufacturing method.

  In order to solve the above-mentioned conventional problems, the inventors of the present application have made extensive studies on the adsorption fixing sheet and the manufacturing method thereof. As a result, the inventors have found that the above-described object can be achieved with the following configuration, and have completed the present invention.

  That is, in order to solve the above-described problem, an adsorption fixing sheet according to the present invention is an adsorption fixing sheet that is used for sucking and fixing a member to be adsorbed and includes at least a porous sheet. An unevenness having an average interval of 0.1 μm to 20 μm is provided in the non-opening portion of the suction surface of the quality sheet to the member to be sucked. Here, the “average interval” means that a certain reference length is extracted from the non-perforated portion in the direction parallel to the suction surface, and the distance from the concave portion in the extracted portion to the adjacent concave portion is obtained. Mean the averaged value.

  The porous sheet is preferably composed of a sintered body containing ultra high molecular weight polyethylene.

  Further, the surface roughness (Ra) of the adsorption surface is preferably 1.2 μm or less, and the adhesive force with the adhesive tape is preferably 1.0 N / 19 mm or less. Here, the “surface roughness (Ra)” is a value measured not only for the portion where the unevenness is provided, but also for the holes on the suction surface.

  In addition, the sheet for adsorbing and fixing according to the present invention may be configured such that one or more other porous sheets are laminated on the surface opposite to the adsorbing surface of the porous sheet.

  In order to solve the above-mentioned problem, a method for manufacturing a suction fixing sheet according to the present invention is used for suction fixing of a member to be suctioned, and a method for manufacturing a suction fixing sheet comprising at least a porous sheet. And the process of producing the said porous sheet and the process of forming the unevenness | corrugation with an average space | interval of 0.1 micrometer-20 micrometers on the surface of the said porous sheet are characterized by the above-mentioned.

  The step of producing the porous sheet includes a step of filling a die with ultrahigh molecular weight polyethylene powder and sintering under a predetermined condition to produce a block-like porous body, and the step of producing the block-like porous body. And a step of cutting the sheet into a sheet having a thickness to produce a porous sheet.

  Furthermore, the unevenness can be formed by transferring the shape of the surface of a mold member having a surface roughness (Ra) of 0.01 to 5 μm to the suction surface side of the porous sheet.

  With the configuration of the adsorption fixing sheet according to the present invention, the contact state with the member to be adsorbed is set to multipoint contact by providing irregularities in the non-opening portion of the adsorption surface of the porous sheet. Thereby, the effective contact area of a to-be-adsorbed member and an adsorption | suction surface is reduced, and the peelability between a to-be-adsorbed member and an adsorption | suction fixed sheet is improved. As a result, even if the member to be adsorbed is extremely thin, it is possible to prevent tearing, scratching, and the like from occurring during peeling.

  Furthermore, by setting the average interval of the unevenness on the suction surface to 0.1 μm or more, it is possible to prevent the unevenness from being removed by the attracted member when the attracted member is sucked and fixed. On the other hand, by setting the average interval to 10 μm or less, the interval between adjacent convex portions is prevented from being excessively widened. Thereby, for example, when a dielectric sheet is used as the member to be attracted, when the sheet is sucked and fixed to the suction fixing sheet, the dielectric sheet is prevented from being embedded in the hole of the porous sheet. As a result, deformation of the dielectric sheet and generation of defects such as scratches can be reduced.

  Further, when the porous sheet comprises ultra high molecular weight polyethylene, a porous sheet having a low friction coefficient and excellent wear resistance and impact resistance can be obtained.

  Furthermore, when the surface roughness (Ra) of the suction surface is 1.2 μm or less, the dielectric sheet is embedded in the holes of the porous sheet when the dielectric sheet is sucked and fixed to the suction fixing sheet. To prevent. As a result, deformation of the dielectric sheet and generation of defects such as scratches can be reduced. On the other hand, by making the adhesive force with the adhesive tape 1.0 N / 19 mm or less, it becomes easy to peel the member to be adsorbed from the adsorption fixing sheet.

  In addition, with the method for manufacturing a suction fixing sheet according to the present invention, it is possible to manufacture a suction fixing sheet including a porous sheet having irregularities on the suction surface using existing process equipment. Therefore, when manufacturing the suction fixing sheet according to the present invention, it is not necessary to introduce new equipment, and as a result, an increase in manufacturing cost can be suppressed. Further, even when a dielectric sheet or the like is used as the member to be attracted, for example, it is possible to manufacture a suction fixing sheet sufficiently corresponding to the thinning of the dielectric sheet.

  An embodiment of the present invention will be described with reference to FIG. FIG. 1 is a cross-sectional view illustrating a schematic configuration of a suction fixing sheet according to the present embodiment. In FIG. 1, parts unnecessary for explanation are omitted, and there are parts shown enlarged or reduced for easy explanation.

  As shown in FIG. 1, the suction fixing sheet according to the present invention is used for suction fixing of a member to be attracted, and includes at least a porous sheet 1.

  The porous sheet 1 is a sheet made of, for example, a plastic porous body, and has fine irregularities 2 on the surface thereof excluding the non-opening portions 3.

  The plastic is not particularly limited, and various conventionally known plastics can be employed. Specifically, for example, polyethylene, ultra high molecular weight polyethylene (hereinafter referred to as “UHMWPE”), polypropylene, polystyrene, polyamide, polyester, polyacryl, fluororesin (polytetrafluoroethylene, etc.), butadiene rubber, styrene butadiene rubber, isoprene. Examples thereof include those made of polymer materials such as rubber and nitrile rubber.

  Of these plastics, UHMWPE is preferred in the present invention. This is because the porous sheet 1 made of UHMWPE has a low friction coefficient, excellent wear resistance, and low cost. Here, the molecular weight of UHMWPE is preferably 500,000 or more, and more preferably 1,000,000 or more from the viewpoint of wear resistance. Specific examples of UHMWPE include commercially available Hi-Zex Million (trade name, manufactured by Mitsui Chemicals), Hostalen GUR (trade name, manufactured by Ticona), and the like. In addition, the said molecular weight says the measured value by ASTMD4020.

  0.1-20 micrometers is preferable and, as for the average space | interval of the said unevenness | corrugation 2, 1-10 micrometers is more preferable. If the average interval is smaller than 0.1 μm, there is a disadvantage that the unevenness 2 is shaved when the member to be attracted is sucked and fixed. On the other hand, if the average interval is larger than 20 μm, the interval between the convex portions supporting the member to be attracted is too wide, and the member to be attracted may be deformed or scratched.

  The surface roughness (Ra) of the porous sheet 1 is preferably 1.0 μm or less, and more preferably 0.8 μm or less. When the surface roughness is larger than 1.0 μm, the attracted member to be sucked and fixed is deformed, or a defect such as a scratch is caused, which causes a defect. However, when the porous sheet 1 is made of UHMWPE, the lower limit of the surface roughness is 0.1 μm or more. If it is smaller than 0.1 μm, the unevenness 2 may be easily worn by use.

  The thickness of the porous sheet 1 can be appropriately set according to the use and the like, but is preferably in the range of 0.1 mm to 3.0 mm. If the thickness is less than 0.1 mm, the mechanical strength of the porous sheet 1 may be reduced and may be broken during use, and the workability when the porous sheet 1 is attached to a lamination jig or the like may be reduced. . On the other hand, if the thickness is larger than 3.0 mm, the air permeability of the porous sheet 1 is lowered.

  In addition, the porosity of the porous sheet 1 can be appropriately set according to the use or the like, but is preferably in the range of 10 to 70%. When the porosity is less than 10%, there is a tendency that the air permeability decreases and the friction coefficient increases. On the other hand, when it exceeds 70%, the mechanical strength of the porous sheet 1 decreases. The porosity is calculated from the following formula (1).

本発明に係る吸着固定用シートは、被吸着部材を吸引固定して搬送した後に剥離する場合、できるだけ剥離性に優れるほうが好ましい。この剥離性を、一般的な粘着テープ（Ｎｏ．３１、日東電工（株）製）における接着力により評価した場合、接着力が小さい程剥離性に優れる為、接着力が小さい方が良い。具体的には、接着力が１．０Ｎ／１９ｍｍ以下であることが好ましく、０．８Ｎ／１９ｍｍ以下であることがより好ましい。接着力が１．０Ｎ／１９ｍｍより大きいと、誘電シートを剥離した際、多孔質シート１の表面に被吸着部材がそのまま残り、剥離の不具合が生じる恐れがある。また、この接着力は表面粗さが大きい程小さくなる傾向がある。この為、接着力が小さ過ぎると表面粗さが大きすぎて、被吸着部材の吸引固定時にキズ等が発生する。よって、かかる観点からは、接着力が０．３Ｎ／１９ｍｍ以上であることが好ましい。

In the case where the adsorbing and fixing sheet according to the present invention is peeled after the adsorbed member is sucked and fixed and conveyed, it is preferable that the adhering and fixing sheet is as excellent in peelability as possible. When this peelability is evaluated by the adhesive strength of a general pressure-sensitive adhesive tape (No. 31, manufactured by Nitto Denko Corporation), the smaller the adhesive strength, the better the peelability. Specifically, the adhesive strength is preferably 1.0 N / 19 mm or less, and more preferably 0.8 N / 19 mm or less. If the adhesive force is greater than 1.0 N / 19 mm, when the dielectric sheet is peeled off, the adsorbed member remains on the surface of the porous sheet 1, which may cause a peeling failure. Moreover, this adhesive force tends to decrease as the surface roughness increases. For this reason, if the adhesive force is too small, the surface roughness is too large, and scratches or the like are generated when the attracted member is sucked and fixed. Therefore, from this point of view, the adhesive strength is preferably 0.3 N / 19 mm or more.

  Further, the friction coefficient of the porous sheet 1 is preferably 0.3 or less, and more preferably 0.2 or less. When the friction coefficient exceeds 0.3, the life when used for suction fixation tends to be shortened.

  The porous sheet 1 according to the present invention may be subjected to antistatic treatment. By performing the antistatic treatment, for example, a spark due to the charging of the porous sheet 1 can be avoided in the dicing process of the semiconductor wafer, and damage to the wafer due to the spark can be prevented. Moreover, it is possible to prevent dust and dirt from adhering to a workpiece such as a semiconductor wafer.

  In addition, the sheet | seat for adsorption fixation which concerns on this invention may be the porous sheet 1 single-piece | unit. Moreover, the laminated body which laminates | stacks several other porous sheets from which a hole diameter, intensity | strength, air permeability, etc. differ may be sufficient. In this case, the other porous sheet is laminated on the surface opposite to the adsorption surface of the porous sheet 1.

  The porous sheet 1 according to the present invention may be colored. The UHMWPE porous sheet is white and opaque, but when it is colored in an arbitrary color, for example, there are the following advantages. When the UHMWPE porous sheet is used for cutting the glass plate for liquid crystal, a scribing mark (near white line) is attached to the glass plate in the scribing process. If the porous sheet is white, the porous material below the glass plate It may be difficult to distinguish between the sheet and the scribe mark by image recognition, and processing control in subsequent cutting processing may be impossible. However, if the UHMWPE porous sheet is colored in any color other than white, the image of the scribe mark can be easily recognized and the cutting process can be performed with high accuracy by comparing the white color of the scribe mark with the color of the porous sheet. It becomes like this.

  Next, the manufacturing method of the suction fixing sheet according to the present invention will be described.

  The method for producing a sheet for adsorbing and fixing according to the present invention includes at least a step of producing a porous sheet 1 and a step of forming irregularities 2 having an average interval of 0.1 μm to 20 μm on the surface of the porous sheet 1. . Hereinafter, a case where UHMWPE is used will be described as an example.

  For producing the porous sheet 1 made of UHMWPE, various conventionally known methods can be adopted. Specifically, for example, an extraction method, a sintering method (Japanese Patent Publication No. 5-66855) and the like can be mentioned.

  Among the above methods, when it is desired to provide the unevenness 2 after the surface of the porous sheet 1 is flattened, it is preferable to employ a sintering method. The sintering method is performed as follows. That is, first, UHMWPE powder (particle size is usually 30 to 200 μm) is filled in a mold, and then this is sintered in a steam atmosphere heated above the melting point of UHMWPE to obtain a block-shaped porous body. In this way, the UHMWPE powder is filled in a mold and sintered in a heated steam atmosphere, and therefore, a mold having at least one opening (for heating steam introduction) is used. The time required for sintering varies depending on the amount of powder filling, the temperature of water vapor, and the like, but is usually about 1 to 12 hours.

  Since the water vapor used at this time raises the temperature to the melting point of UHMWPE or higher, it is in a pressurized state, so that it can easily enter between the UHMWPE powders filled in the mold. In order to facilitate the entry of heated water vapor between the UHMWPE powders, the powder was filled in a mold, the mold was placed in a pressure vessel, subjected to a degassing operation to reduce the pressure, and then heated. You may make it sinter in water vapor | steam atmosphere. The degree of decompression at this time is not particularly limited, but is preferably about 0.13 to 13 kPa.

  Therefore, the sintering of the UHMWPE powder filled in the mold is performed by providing a steam inlet pipe and its open / close valve in the pressure vessel, degassing the air between the powders, and then stopping the decompression or continuing the decompression. The method can be carried out by opening a steam valve and introducing heated steam.

  During this sintering, the UHMWPE powder is heated to a temperature above its melting point, but its melt viscosity is high, so it does not flow very much, and part or most of the powder shape is maintained. Heat-sealing forms a block-like porous body (non-contact portions between the powders become pores of the porous molded body). In addition, although it can also pressurize if desired in the case of sintering, it is preferable that the pressure shall be about 1 Mpa or less normally.

  After performing the sintering as described above, it is cooled. Upon cooling, in order to prevent the occurrence of cracks in the block-shaped porous body, it is preferable to avoid rapid cooling. For example, a method of cooling by leaving it at room temperature can be employed. The cooling may be performed while the block-shaped porous body is placed in a mold, or may be performed by removing it from the mold. Thus, after cooling a block-shaped porous body, a porous sheet can be obtained by cutting to predetermined thickness with a lathe.

  The pore size and porosity of the porous sheet obtained by the above method are determined by the particle size of the UHMWPE powder used and the presence or absence of pressure during sintering. If the other conditions are the same, a porous sheet having a larger porosity and a higher porosity can be obtained as the particle size of the powder used is larger. Further, when no pressure is applied during sintering, a porous sheet having a larger pore diameter and a higher porosity can be obtained than when pressurized. Further, when the pressure is applied during sintering, the higher the pressure, the smaller the pore diameter and the lower the porosity.

  As described above, the UHMWPE porous sheet obtained by such a method has a sheet shape in which the adjacent UHMWPE powder maintains a part or most of the shape thereof and the powders are thermally fused at the contact portion. And it has the microstructure which makes the non-contact part of powder mutual a hole. The microstructure of the porous sheet is obtained by, for example, cutting the porous sheet along the thickness direction and observing the cut surface using a scanning electron microscope (the magnification is appropriately set, but is usually about 100 to 1000). Can be).

  The formation of the irregularities 2 is performed as follows. That is, for example, by using a mold member having fine unevenness with a surface roughness of about 0.01 μm to 5 μm, the uneven shape on the surface of the mold member is transferred to the porous sheet. Thereby, the unevenness | corrugation 2 whose average space | interval is 0.1 micrometer-20 micrometers is formed. The mold member is not particularly limited, and for example, a plastic sheet or the like can be adopted. However, in the present invention, a mold member having an uneven shape on a flat surface is particularly preferable. This is because, when such a mold member is used, the same effect as that provided with the unevenness 2 is obtained after the adsorption surface of the porous sheet 1 is flattened. That is, by using such a mold member, for example, fine irregularities 2 are not formed on relatively large convex portions present on the suction surface. As a result, even when an extremely thin member to be adsorbed such as a dielectric sheet is used, the occurrence of deformation and scratches can be further suppressed.

  Examples of the shape transfer method include a press method, a method in which a plastic sheet and a porous sheet are placed on a heated roll, and a pressure is applied between the opposite rolls. Among these methods, the method using a roll has an advantage that it can be manufactured at low cost because continuous production is possible. The roll temperature of the heated roll is appropriately changed depending on the type of the porous sheet. For example, when UHMWPE having a molecular weight of 1 million or more is used, the roll temperature is preferably in the range of 130 ° C to 170 ° C. As for pressurization, a pressurization time of about several seconds or less is sufficient. Therefore, it is possible to process in an extremely short time.

  In the method for manufacturing the suction fixing sheet according to the present invention, the step of flattening the surface of the porous sheet may be performed before the step of forming the irregularities 2 on the suction surface of the porous sheet. Good. After the surface of the porous sheet is once smoothed, the unevenness 2 is formed on the surface, so that the fine unevenness 2 is not formed on, for example, a relatively large protrusion existing on the adsorption surface. As a result, even when the member to be sucked is sucked and fixed to the suction fixing sheet, the member to be sucked can be further prevented from being deformed or scratched.

  As a method for flattening the surface of the porous sheet, a conventionally known method can be employed. Specifically, for example, a method of laminating a polymer sheet with a smooth surface such as a polyethylene terephthalate sheet having a flat surface, a metal sheet such as a stainless steel, etc., and heating and pressurizing (JP 2001-28390 A), etc. Is mentioned.

  In addition, when the porous sheet 1 according to the present invention is subjected to antistatic treatment, various conventionally known methods can be employed. For example, when a porous sheet is produced by the above-described method, the powder and the antistatic agent may be mixed prior to filling the UHMWPE powder into the mold, and the mixture may be used for the operation.

  In addition, a method in which a block-shaped porous body or a porous sheet obtained by cutting the block-shaped porous body is brought into contact (immersion, coating, etc.) with an antistatic agent-containing liquid and the porous body or sheet is impregnated with an antistatic agent may be employed. it can. The amount of the antistatic agent used in this treatment is not particularly limited, but usually the proportion of the antistatic agent in the weight of the treated porous sheet is in the range of 0.5 to 2% by weight. .

  As the antistatic agent, commercially available products such as “ELEKON ORW (manufactured by New Fine Chemical Co., Ltd.)” and “Electro Stripper (manufactured by Kao Corporation)” can be used, and inorganic materials such as carbon black powder and metal powder can be used. A conductive material, a surfactant, a conductive polymer, or the like can be used.

  Further, in order to color the porous sheet 1 according to the present invention, in the case of the above-described method, for example, prior to filling the mold of UHMWPE powder, the powder and the pigment are mixed and the mixture is used to work. Good. Thereby, the colored porous sheet 1 can be produced.

  Moreover, when producing the laminated body which laminated | stacked the several porous sheet as the sheet | seat for adsorption fixation which concerns on this invention, the method described below can be employ | adopted, for example. That is, a method using a press, a method in which a sheet is placed on a heated roll, and pressure is applied between the opposite rolls, and the like. However, in consideration of productivity and cost, a method using a roll is preferable. In the case of this method, the roll temperature varies greatly depending on the type of the resin material to be used, but in the case of UHMWPE having a molecular weight of 1 million or more, it is preferably within a range of 130 ° C to 170 ° C.

  Hereinafter, preferred embodiments of the present invention will be described in detail by way of example.

  First, UHMWPE powder (molecular weight 9 million, melting point 135 ° C., average particle size 110 μm) was filled into a metal mold having an inner diameter of 500 mm and a height of about 1000 mm, and this was put into a metal pressure vessel, and the inside of the vessel was depressurized to 4 kPa. .

  Thereafter, heated water vapor was introduced, heated at 160 ° C. × 6 atm for 5 hours, and then slowly cooled to prepare a cylindrical sintered porous body (block-shaped porous body). This was cut into a sheet by cutting to a thickness of 1.0 mm using a lathe to obtain a UHMWPE porous sheet.

  In order to form fine irregularities on the surface of the porous sheet, it was passed through a rubber roll facing a hot roll heated to 160 ° C. together with the transfer material at a speed of 0.5 m / min. The porous sheet was sufficiently preheated, and the pressure between the rolls was 0.2 MPa (gauge pressure). The pressurization time was about 0.5 seconds. Then, it cooled at room temperature and obtained the sheet | seat for adsorption fixation which concerns on the present Example 1. As the transfer material, Lumirror X42 (thickness: 25 μm) manufactured by Toray Industries, Inc. was used. The surface roughness Ra of this material was 0.5 μm.

  UHMWPE powder (molecular weight: 9 million, melting point: 136 ° C., average particle size: 70 μm) was filled in the same mold as in Example 1, placed in a metal pressure vessel, and the inside of the vessel was depressurized to 4 kPa.

  Thereafter, heated water vapor was introduced, heated at 170 ° C. × 6 atm for 5 hours, and then slowly cooled to prepare a cylindrical sintered porous body. This was cut to a thickness of 0.1 mm using a lathe to obtain a porous sheet made of UHMWPE.

  Next, the obtained porous sheet and the porous sheet according to Example 1 were laminated to obtain a laminate. The lamination conditions were a temperature of 145 ° C., a pressure of 0.2 MPa, and a heating / pressurizing time of 0.3 seconds.

  Furthermore, in order to form unevenness on the surface of this laminate, the film was passed between rolls under the same conditions as in Example 1. Then, it cooled at room temperature and obtained the sheet | seat for adsorption fixation which concerns on the present Example 2. As a transfer material, Toray Co., Ltd. Lumirror X44 (thickness 25 μm) was used. The surface roughness Ra of this material was 0.2 μm.

  UHMWPE powder (molecular weight 5 million, melting point 135 ° C., average particle size 150 μm) was filled in the same mold as in Example 1, placed in a metal pressure vessel, and the inside of the vessel was depressurized to 4 kPa.

  Thereafter, heated water vapor was introduced, heated at 170 ° C. × 6 atm for 5 hours, and then slowly cooled to prepare a cylindrical sintered porous body. This was cut into a sheet by cutting to a thickness of 1.0 mm using a lathe to obtain a porous sheet made of UHMWPE.

  In order to form fine irregularities on the surface of the porous sheet, it was passed through a rubber roll facing a hot roll heated to 160 ° C. together with the transfer material at a speed of 0.5 m / min. The sheet was sufficiently preheated, and the pressure between the rolls was 0.2 MPa (gauge pressure). Moreover, the pressurization time at this time was about 0.5 second. Then, it cooled at room temperature and obtained the sheet | seat for adsorption fixation which concerns on the present Example 3. As a transfer material, Kimoto Co., Ltd. product, mattle mirror deep punching (thickness 250 μm) was used. The surface roughness Ra of this material was 1.0 μm.

  In Example 4, a suction-fixing sheet according to Example 4 was obtained in the same manner as in Example 3 except that the following transfer materials were used. That is, as the transfer material, an aluminum foil manufactured by Mitsubishi Aluminum Co., Ltd., and a surface of A3303-H (thickness 0.1 mm) with hub polishing was used. The surface roughness Ra of this material was 0.05 μm.

Comparative Example 1

  UHMWPE powder (molecular weight 2.5 million, melting point 136 ° C., average particle size 40 μm) was filled in a mold similar to that in Example 1, placed in a metal pressure vessel, and the inside of the vessel was depressurized to 4 kPa. At this time, heated water vapor was introduced, heated at 160 ° C. × 6 atm for 5 hours, and then slowly cooled to prepare a cylindrical sintered porous body.

  This was cut into a sheet with a thickness of 0.3 mm using a lathe to obtain a porous sheet made of UHMWPE.

  Next, a 0.25 mm thick PET film (Toray, Lumirror S10) is placed on the upper surface of the porous sheet, heated in a press device at a temperature of 140 ° C. and a pressure of 5 kPa for 3 hours, and then left as it is. The surface was flattened by cooling. As a result, an adsorption fixing sheet according to Comparative Example 1 was obtained.

Comparative Example 2

  In this comparative example 2, the porous sheet before the unevenness forming process produced in the above-mentioned example 1 was produced, and this was used as the adsorption fixing sheet according to this comparative example 2.

(Various measurements and evaluations)
About each adsorption fixing sheet produced as described above, the average interval of unevenness and the surface roughness were measured. Moreover, the adhesive tape was affixed on the surface of each adsorption fixing sheet, and the adhesive force with the adhesive tape at this time was measured. The results are shown in Table 1 below. Measurement methods and measurement conditions are as follows.

[Average interval of unevenness]
The average spacing of the irregularities on the suction surface of the suction fixing sheet was observed by SEM (scanning electron microscope). The observation was performed by extracting a certain reference length with respect to the non-opening portion in a direction parallel to the suction surface, and measuring all the distances from the concave portion in the extracted portion to the adjacent concave portion. Furthermore, the average value of unevenness was calculated by averaging the measured values. The observation magnification was 500 times.

[Surface roughness]
The surface roughness of the adsorption fixing sheet was measured using a stylus type surface roughness meter (Tokyo Seimitsu Co., Ltd., Surfcom 550A). The measurement conditions were a tip diameter R of 250 μm, a speed of 0.3 mm / sec, and a measurement length of 4 mm. The surface roughness (Ra) was measured not only for the portion where the irregularities were provided, but also for the holes on the suction surface.

[Adhesive strength with adhesive tape]
Adhesive strength with the adhesive tape was measured by applying the adhesive tape to the surface (adsorption surface) of each adsorption fixing sheet and allowing it to stand at room temperature for a certain time, and then measuring the adhesive strength with a tensile tester. The measurement environment was also room temperature.

A tensile tester (Autograph AG-1 manufactured by Toyotsu Seisakusho Co., Ltd.) was used as the measuring device. No-31B (Nitto Denko) was used for the adhesive tape.
The measurement conditions were as follows: 1 reciprocation of the 2N roller for sticking, 5 minutes of standing time after sticking, sample width of 19 mm, tensile speed of 300 mm / min, and peel angle of 180 degrees.

[Dielectric sheet suction fixation and peeling]
The suction fixing and peeling of the dielectric sheet using each adsorption fixing sheet was performed as follows.

  That is, each suction fixing sheet was attached to a suction machine, and a dielectric sheet (thickness 5 μm) on the carrier film was sucked and fixed, and then exhausted and pressurized to be detached. At this time, the surface of the dielectric sheet at the time of attracting and fixing the dielectric sheet and after peeling was observed, and the result was evaluated. The evaluation criteria were as follows. That is, the case where the dielectric sheet was attracted and fixed without any problem and no abnormalities were observed on the surface of the dielectric sheet was considered good. In addition, when there was an abnormality such as peeling or sticking when the dielectric sheet was sucked and fixed and peeled, or when there was an abnormality such as deformation or scratches on the surface of the dielectric sheet, it was regarded as defective. The results are shown in Table 1 below.

同表から明らかな様に、実施例１〜３に係る吸着固定用シートは、極めて薄い誘電シートを吸引固定及び剥離する際に、誘電シートにダメージを与えず、かつ剥離が容易であったことを示している。

As is clear from the table, the suction fixing sheets according to Examples 1 to 3 did not damage the dielectric sheet when the extremely thin dielectric sheet was suction fixed and peeled off, and was easy to peel off. Is shown.

  On the other hand, with respect to the suction fixing sheet according to Comparative Example 1, since the surface roughness was small, the dielectric sheet was difficult to be damaged, but a dielectric sheet peeling failure was observed. This is supported by the fact that the adhesive force of the suction fixing sheet according to Comparative Example 1 is larger than that of the suction fixing sheet according to each Example.

  In addition, the suction fixing sheet according to Comparative Example 2 has a large surface roughness compared to the suction fixing sheet according to each example, and thus the dielectric sheet is damaged.

It is sectional drawing which shows schematic structure of the sheet | seat for adsorption fixation which concerns on embodiment of this invention. It is sectional drawing which shows roughly the surface of the conventional sheet | seat for adsorption fixed conveyance. It is sectional drawing which shows schematically the surface of the other conventional sheet for adsorption fixed conveyance. It is sectional drawing which shows roughly the surface of the other conventional adsorption fixed conveyance sheet.

Explanation of symbols

1 Porous sheet 2 Concavity and convexity 3 Non-opening part

Claims (7)

A suction fixing sheet that is used for sucking and fixing a member to be adsorbed and includes at least a porous sheet,
An adsorption fixing sheet, wherein unevenness having an average interval of 0.1 μm to 20 μm is provided in a non-opening portion of the adsorption surface of the porous sheet with respect to the member to be adsorbed.   The adsorption fixing sheet according to claim 1, wherein the porous sheet is composed of a sintered body containing ultrahigh molecular weight polyethylene.   The adsorption fixing according to claim 1 or 2, wherein the adsorption surface has a surface roughness (Ra) of 1.2 µm or less and an adhesive strength with an adhesive tape of 1.0 N / 19 mm or less. Sheet.   The adsorption according to any one of claims 1 to 3, wherein another porous sheet of one layer or a plurality of layers is laminated on a surface opposite to the adsorption surface of the porous sheet. Seat for fixing. A method for producing a suction fixing sheet that is used for suction fixing of a member to be adsorbed and includes at least a porous sheet,
Producing the porous sheet;
And a step of forming irregularities having an average interval of 0.1 μm to 20 μm on the surface of the porous sheet. The step of producing the porous sheet includes
Filling the mold with ultra high molecular weight polyethylene powder and sintering under predetermined conditions to produce a block-shaped porous body;
The manufacturing method of the sheet | seat for adsorption fixation of Claim 5 including the process of cutting the said block-shaped porous body into the sheet form of predetermined thickness, and producing a porous sheet. 6. The unevenness is formed by transferring the shape of the surface of a mold member having a surface roughness (Ra) of 0.01 to 5 [mu] m to the suction surface side of the porous sheet. Or the manufacturing method of the sheet | seat for adsorption fixation of 6.

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