JP4868925B2 - Cleaning layer, manufacturing method thereof, pressure-sensitive adhesive sheet, cleaning sheet, transport member with cleaning function, and cleaning method - Google Patents

Description

  The present invention relates to a pressure-sensitive adhesive layer having a discontinuous recess on the surface and a method for producing the same. Moreover, this invention relates to the adhesive sheet which has the said adhesive layer. The present invention also relates to a cleaning sheet using the pressure-sensitive adhesive sheet, a transport member with a cleaning function using the cleaning sheet, and a substrate processing apparatus cleaning method using the same.

  Although the pressure-sensitive adhesive sheet of the present invention can be used in various applications, the above-mentioned pressure-sensitive adhesive layer having a recess on the surface can control the surface pressure-sensitive adhesiveness and foreign matter collecting property, so that it does not adhere to various substrate devices themselves. It is useful as a sheet having a collecting property, specifically, a sheet for cleaning various substrate processing apparatuses. For example, the cleaning sheet of the present invention is useful as a cleaning sheet for a substrate processing apparatus that does not like foreign matter, such as a manufacturing apparatus or an inspection apparatus for semiconductors, flat panel displays, and printed boards.

  Manufacturing apparatuses such as semiconductors, flat panel displays, and printed circuit boards, and various substrate processing apparatuses transport each transport system and the substrate in physical contact with each other. At this time, if foreign matter adheres to the substrate or the transport system, subsequent substrates are contaminated one after another. Therefore, it is necessary to periodically stop the apparatus and perform a cleaning process for removing foreign substances. For this reason, there existed a problem that an operation rate fall and a lot of labor were needed. In addition, the presence of foreign matter on other parts may occur due to human intervention during cleaning. In order to solve these problems, a method of cleaning and removing adhered foreign substances in the substrate processing apparatus by transporting a substrate to which an adhesive is fixed (Patent Document 1), or a substrate back surface by transporting a plate-like member There has been proposed a method (Patent Document 2) for removing foreign substances adhering to the surface.

  The method described in Patent Document 1 is an effective method for overcoming the aforementioned problems. However, in this method, there is a possibility that the adhesive substance and the device contact portion are strongly adhered and cannot be peeled off, and there is a possibility that the substrate cannot be reliably transported or the transport device is damaged. Further, there is a possibility that the adhesive substance adhering to the substrate transfer device may contaminate the substrate.

  Moreover, although the method described in Patent Document 2 can be transported without any problem, there is a problem in that it is inferior in essential dust removal. In general, a substrate to which these adhesive substances are fixed is generally protected with a release film to which a release agent such as silicone is applied, before use. However, this method has a problem that the release agent component is transferred to the surface of the cleaning layer, and the transfer release agent component contaminates the substrate contact portion of the transport apparatus.

Also, a cleaning tape (Patent Document 3) in which a polar screen layer such as a knitted fabric is provided on the surface of the adhesive layer, and a cleaning sheet (Patent Document 4, Patent Document 5) using a porous non-adhesive layer as a cleaning layer. Has been proposed. However, these cleaning sheets satisfy a certain degree of transportability in the substrate processing apparatus and removal of foreign substances adhering to the apparatus, but are not sufficiently satisfied.
JP-A-10-154686 JP-A-11-87458 JP-A-11-232621 JP 2002-329699 A JP 2003-115521 A

  In light of such circumstances, the present invention provides a pressure-sensitive adhesive layer suitable for a cleaning sheet, and a method for producing the same, which are excellent in both transportability in a substrate processing apparatus and removability of foreign matter adhered in the apparatus. The purpose is to provide.

  The present invention also provides a pressure-sensitive adhesive sheet having the pressure-sensitive adhesive layer, a cleaning sheet using the pressure-sensitive adhesive sheet, a transport member with a cleaning function using the cleaning sheet, and It is an object of the present invention to provide a cleaning method for a substrate processing apparatus using these.

  As a result of intensive studies to achieve the above object, the present inventors have used the pressure-sensitive adhesive layer shown below as a cleaning layer in cleaning and removing the adhered foreign matter in the substrate processing apparatus. It has been found that foreign matters can be peeled and removed easily and reliably without causing the problem of transportability, and the present invention has been completed.

That is, the present invention is a pressure-sensitive adhesive layer having a planar surface, comprising a cured product of a radiation-curable or thermosetting acrylic pressure-sensitive adhesive containing an acrylic polymer,
Having discontinuous recesses on the surface of the pressure-sensitive adhesive layer, and
The opening of the recess is substantially circular, and the average opening diameter is 0.1 to 3 μm,
The standard deviation of the opening diameter is 0.7 μm or less,
The distribution of the openings relates to a pressure-sensitive adhesive layer characterized in that the standard deviation of the center-to-center distance between adjacent openings is 1 μm or less.

  In the pressure-sensitive adhesive layer, the ratio of the projected area of the discontinuous recesses to the total projected area of the surface of the pressure-sensitive adhesive layer is preferably 15% to 90%.

  The pressure-sensitive adhesive layer preferably has a ratio (h / H) of the depth (h) of the concave portion to the thickness (H) of the pressure-sensitive adhesive layer of 0.01 to 0.1.

  In the pressure-sensitive adhesive layer, the radiation curable or thermosetting acrylic pressure-sensitive adhesive preferably contains an acrylic polymer and a polymerizable unsaturated compound.

The present invention is also a method for producing the pressure-sensitive adhesive layer,
A pressure-sensitive adhesive composition containing an acrylic polymer-containing radiation-curable or thermosetting acrylic pressure-sensitive adhesive and a compound that is not compatible with the acrylic polymer is used as a solvent for dissolving the acrylic polymer (A ) And a pressure-sensitive adhesive composition solution dissolved in a mixed solvent containing a compatibilizing solvent (B) that compatibilizes both the acrylic polymer and the incompatible compound is applied onto a substrate and dried. (1) forming an adhesive composition layer by
A step of forming a pressure-sensitive adhesive layer precursor having a phase separation structure of the cured product and the incompatible compound while curing the acrylic pressure-sensitive adhesive by irradiating or heating the pressure-sensitive adhesive composition layer ( 2) and
It has the process (3) of removing an incompatible compound from the obtained adhesive layer precursor, and relates to the manufacturing method of the adhesive layer characterized by the above-mentioned.

  In the method for producing the pressure-sensitive adhesive layer, the compatibilizing solvent (B) that is compatible with both the acrylic polymer and the incompatible compound has a χ parameter that is a compatibility parameter of 0 with respect to the acrylic polymer. 0.5 to 3 and preferably 0.5 to 3 with respect to the incompatible compound.

  In the method for producing the pressure-sensitive adhesive layer, the incompatible compound preferably has a χ parameter of 7 or more with respect to the acrylic polymer and a boiling point of 190 ° C. or more.

  In the method for producing the pressure-sensitive adhesive layer, the pressure-sensitive adhesive composition solution is in a uniform state, but the solvent (A) and the compatibilizing solvent so that phase separation occurs in the absence of the compatibilizing solvent (B). Preferably (B) is selected.

  In the method for producing the pressure-sensitive adhesive layer, an alcohol solvent is suitably used as the compatibilizing solvent (B).

  In the method for producing the pressure-sensitive adhesive layer, the step (3) can be performed by removing an incompatible compound from the pressure-sensitive adhesive layer precursor by heating.

  In the method for producing the pressure-sensitive adhesive layer, the step (3) can remove incompatible compounds from the pressure-sensitive adhesive layer precursor by solvent extraction. As the solvent used for the solvent extraction, liquefied carbon dioxide or carbon dioxide in a supercritical state can be used.

  In the method for producing the pressure-sensitive adhesive layer, in the step (2), it is preferable that the pressure-sensitive adhesive composition layer surface is irradiated with radiation or heated while being covered with a cover film.

  The present invention also relates to a pressure-sensitive adhesive sheet, wherein the pressure-sensitive adhesive layer is provided on at least one side of a support so that the discontinuous recesses are on the surface.

  The present invention also relates to a cleaning sheet, wherein the pressure-sensitive adhesive layer is provided as a cleaning layer on at least one surface of a support so that the discontinuous recesses are on the surface.

  In the present invention, the pressure-sensitive adhesive layer is provided as a cleaning layer on one side of the support so that the discontinuous recesses are on the surface, and the other side has a pressure-sensitive adhesive layer for fixing. The present invention relates to a cleaning sheet.

  The present invention also relates to a conveying member with a cleaning function, wherein the cleaning sheet is provided on the conveying member via a fixing adhesive layer.

  The present invention also relates to a cleaning method for a substrate processing apparatus, wherein the cleaning sheet or the transport member with a cleaning function is transported into the substrate processing apparatus.

  Since the pressure-sensitive adhesive layer of the present invention has discontinuous recesses on the surface, the adhesive strength thereof is lower than that of a smooth-structured pressure-sensitive adhesive layer having no recesses on the surface. The pressure-sensitive adhesive layer can control surface adhesiveness by designing the size of the concave portions on the surface and the ratio thereof. Further, when the pressure-sensitive adhesive layer is applied to the cleaning layer in the cleaning sheet, it is possible to control the foreign matter collecting ability with respect to foreign substances of various sizes as well as the surface adhesiveness by designing the size and ratio of the concave portions on the surface. That is, the pressure-sensitive adhesive layer has fine recesses, and since the surface is substantially flat, it comes into very close contact with the foreign matter, and all or a part of the foreign matter enters the recess, so that the foreign matter can be reliably removed. The effect of being able to collect can also be expected. In particular, the pressure-sensitive adhesive layer of the present invention has an average opening diameter of the recesses as fine as 0.1 to 3 μm, and the standard deviation of the opening diameter is 0.7 μm or less, and there is no variation in the opening diameter. There is no variation in characteristics depending on the location of the surface of the pressure-sensitive adhesive layer, which is preferable for achieving the above effects. In addition, the distribution of the openings of the recesses on the surface of the pressure-sensitive adhesive layer is uniformly controlled so that the standard deviation of the center-to-center distance between adjacent openings is 1 μm or less. Is preferable.

  According to the cleaning sheet having such a pressure-sensitive adhesive layer as a cleaning layer, and the conveyance member with a cleaning function using the cleaning sheet, the adhesiveness of the cleaning layer is substantially lower than that of the pressure-sensitive adhesive layer having a smooth surface. On the other hand, when viewed in the μm order, the adhesive itself inside the recess is the same as the adhesive having a smooth surface, so that it strongly adheres to the device contact part when transporting the cleaning sheet or the transport member described later. In addition to being able to reliably transport the substrate processing apparatus, fine foreign matters on the order of μm adhering to the apparatus can be collected and easily and reliably removed without dropping.

  Such a pressure-sensitive adhesive layer can be formed of a radiation curable or thermosetting acrylic pressure-sensitive adhesive. The production method thereof can be performed, for example, by applying the steps (1) to (3). Examples of a method for forming a concavo-convex structure on a fine surface on the order of μm include a transfer method, use of a phase separation phenomenon, ink jet technology, and laser processing. For example, as a method of forming a concavo-convex structure using a phase separation phenomenon, a mixed solvent is evaporated for a position correction tape in Japanese Patent Application Laid-Open No. 2003-277534, and between a poor solvent and a pressure-sensitive adhesive. There is a description that a point-like material of an adhesive is formed on a substrate by utilizing phase separation and a peeling phenomenon. Japanese Patent Application Laid-Open No. 2004-151642 discloses that an ink droplet containing an antiglare property-imparting composition that forms a fine concavo-convex structure is ejected on a transparent substrate by an ink jet method, and is finely applied to the surface of the substrate. There is a description of a method for forming an antiglare layer, which comprises forming an antiglare layer having an uneven structure. However, the structures obtained by these methods are all protrusions and do not form a concave structure. In addition, since these all form a projecting structure, the adhesive force is significantly reduced, and the foreign matter collecting property cannot be ensured. In addition, it is difficult to carry out in a large area. Moreover, the adhesive of a dotted | punctate part may fall out from a base material, and may adhere to a board | substrate conveyance apparatus.

  The pressure-sensitive adhesive layer of the present invention will be described below with reference to the drawings. FIG. 1 is a perspective view conceptually showing the pressure-sensitive adhesive layer of the present invention, and FIG. 2 is a cross-sectional view. As shown in FIGS. 1 and 2, the pressure-sensitive adhesive layer 1 of the present invention has a surface S that is planar and has a discontinuous recess a on the surface S. The surface S being planar means that the thickness (H) of the pressure-sensitive adhesive layer 1 is substantially equal (the difference between the maximum thickness and the minimum thickness is about ± 10%).

  The ratio (existence ratio) of the recesses a on the surface S of the pressure-sensitive adhesive layer 1 is preferably such that the ratio of the projected area of the recesses a to the total projected area of the surface S is 15% to 90%. The ratio is preferably 15% to 80%, more preferably 20% to 70%. In addition, the said projected area is an area ratio of the site | part observed as the recessed part a, when the recessed part a of the adhesive layer 1 is observed from the surface with a microscope. When the projected area of the recess a is too small, the adhesive force of the pressure-sensitive adhesive layer is not substantially reduced, and the desired substrate transportability when used as a cleaning layer may not be sufficiently exhibited. On the other hand, when the projected area of the recess a is too large, the adhesive force of the pressure-sensitive adhesive layer is significantly reduced, and a desired foreign matter collecting property may not be obtained. In addition, the frictional resistance of the pressure-sensitive adhesive layer surface becomes too low, and the structure of the recesses may be destroyed, and the substrate may be back-contaminated during transportation.

  Moreover, the shape of the opening part of the recessed part a is substantially circular, and it is preferable from the point which is easy to suppress adhesive force and formation. The term “substantially circular” refers to a circle or an elliptical shape in which the length of the major axis does not exceed twice the length of the minor axis. However, a honeycomb shape or a quadrangular shape can be included.

  Moreover, the opening part of the said recessed part a is 0.1-3 micrometers in the average opening diameter, and is a fine opening | mouth. The average opening diameter of the openings is preferably 0.1 to 2 μm. The size of the opening of the concave portion a is larger than the size of foreign matter, and if the number is too large, the effect of collecting foreign matter may be reduced. Foreign matter can be collected. For example, if the opening diameter of the opening is about 10 μm, foreign matters having a diameter of 10 μm or more can be collected through some concave portions or flat portions, but foreign matters having a diameter of less than 10 μm can be collected. difficult. On the other hand, as in the present invention, if the average opening diameter of the opening of the concave portion a is 0.1 to 3 μm and a fine mouth can be collected, large foreign substances larger than the opening diameter can be collected. The particle size range is widened. The opening diameter of the opening means the maximum diameter in each opening, and the average opening diameter is an average value of the maximum diameter in each opening obtained by image analysis as described in the examples.

  The standard deviation of the opening diameter is 0.7 μm or less, and the opening diameter of the opening is controlled so as to be approximately the same size. The standard deviation of the opening diameter is preferably 0.6 μm or less.

  Regarding the distribution of the openings of the recesses on the surface of the pressure-sensitive adhesive layer, it is preferable that the standard deviation of the center-to-center distance between adjacent openings is 1 μm or less, and the dispersion of the recesses is uniform. The standard deviation of the center distance is preferably 0.75 μm or less. The “adjacent openings” means openings having the shortest distance between the centers, and the “center distance” means a length when the center points of the openings are connected by a straight line. .

  Further, the cross-sectional shape of the recess a is not particularly specified, but a hemispherical shape is preferable from the viewpoint of controllability of the size of the recess. However, even when the cross-sectional shape is not hemispherical, the desired foreign matter collecting property is ensured. FIG. 2 shows a case where the concave portion a has a hemispherical shape. In addition, when the pressure-sensitive adhesive layer surface is not a discontinuous concave portion but a protrusion (convex portion), it is difficult to obtain a desired foreign matter collecting property due to a significant decrease in the adhesion area.

  Moreover, it is preferable that ratio (h / H) of the depth (h) of the said recessed part a with respect to the thickness (H) of the adhesive layer 1 is 0.01-0.1. The thickness (H) of the pressure-sensitive adhesive layer 1 and the depth (h) of the concave portion a are average values. The size of the recess a is determined by the depth (h) of the recess a when the cross-sectional shape is hemispherical. When the ratio (h / H) exceeds 0.1, the recess a may become too deep, and the strength of the recess wall surface may be insufficient. If the ratio (h / H) is less than 0.01, the necessary foreign matter collecting property may be insufficient if the ratio is less than 0.01. The ratio (h / H) is preferably in the range of 0.01 to 0.05.

  In the present invention, by forming the pressure-sensitive adhesive layer having the concave structure as described above, the adhesion area to the adherend on the surface of the pressure-sensitive adhesive layer can be reduced, while on the other hand, by forming a fine concave structure. Since the adhesion area increases for foreign matters larger than the recess opening diameter, foreign matters can be reliably collected. In addition, there is no variation in the opening diameter of the recess, and in-plane characteristic variation can be suppressed by uniformly dispersing the recess on the surface of the pressure-sensitive adhesive layer.

  The pressure-sensitive adhesive layer preferably has a tensile elastic modulus of 10 MPa to 500 MPa. When the tensile elastic modulus of the pressure-sensitive adhesive layer exceeds 500 MPa, the pressure-sensitive adhesive force on the surface of the pressure-sensitive adhesive layer is low, and even if a concave portion is formed in the pressure-sensitive adhesive layer, the foreign matter collecting function may not be exhibited. In the case of less than 10 MPa, even if a concave portion is formed on the surface of the pressure-sensitive adhesive layer, the surface structure may be deformed and adhered to the inside of the transport device in the case of transportability evaluation. The tensile elastic modulus of the pressure-sensitive adhesive layer is preferably 10 MPa to 300 MPa, and more preferably 10 MPa to 200 MPa. The tensile elastic modulus of these pressure-sensitive adhesive layers can be appropriately set depending on the composition of the acrylic pressure-sensitive adhesive, for example, the blending amount of the acrylic polymer and the polymerizable unsaturated compound (monomer component, oligomer component).

  Further, when the adhesive layer of the present invention is used as a cleaning layer of a cleaning sheet, it is attached to a mirror surface of a silicon wafer with a width of 10 mm and measured at a room temperature (23 ° C.) with a pulling speed of 300 mm / min. The 90 ° peeling adhesion to the silicon wafer is preferably 0.3 N / 10 mm or less. If the adhesive force is 0.3 N / 10 mm or less, it can be said that the transportability is substantially obtained. In addition, since the adhesive layer of this invention has a recessed part on the surface, even if the adhesive force of a base adhesive is made small, a foreign material can be removed by a dent.

  When the pressure-sensitive adhesive layer of the present invention is used as a cleaning layer for a cleaning sheet, a metal piece having a diameter of 50 mm is adhered to the cleaning layer with a load of 2 kg for 3 minutes, and a pulling speed is 100 mm / min at a room temperature of 23 ° C. The force (vertical peeling force) applied when the metal piece is lifted vertically is preferably 0 to 4.5N. If it is this range, it can be said that conveyance property is substantially acquired, maintaining a foreign material collection property in this invention.

  The pressure-sensitive adhesive layer of the present invention has a structure having the recesses, and the material or configuration thereof is not particularly limited as long as the adhesive layer has adhesiveness. Since it is easy to control to the adhesive force of the range, it is preferable that the adhesive layer of this invention is a hardened | cured material of a radiation-curable or thermosetting acrylic adhesive. Hereinafter, the radiation curable or thermosetting acrylic pressure-sensitive adhesive will be described.

  The radiation curable or thermosetting acrylic pressure-sensitive adhesive has a radiation curable or thermosetting functional group such as a carbon-carbon double bond and exhibits adhesiveness without particular limitation. it can. As such a functional group, those having a (meth) acryloyl group are preferable. The (meth) acryloyl group means an acryloyl group and / or a methacryloyl group. Hereinafter, (meta) has the same meaning.

  Examples of the radiation curable or thermosetting acrylic pressure-sensitive adhesive include, for example, a pressure-sensitive acrylic pressure-sensitive adhesive having an acrylic polymer as a base polymer, and a radiation-curable or thermosetting monomer as a polymerizable unsaturated compound. An additive-type curable pressure-sensitive adhesive containing components and oligomer components can be exemplified.

  Examples of the acrylic polymer include (meth) acrylic acid alkyl esters (for example, methyl ester, ethyl ester, propyl ester, isopropyl ester, butyl ester, isobutyl ester, s-butyl ester, t-butyl ester, pentyl ester, isopropyl ester). 1 to 12 carbon atoms of an alkyl group such as pentyl ester, hexyl ester, heptyl ester, octyl ester, 2-ethylhexyl ester, isooctyl ester, nonyl ester, decyl ester, isodecyl ester, undecyl ester, dodecyl ester, etc. Examples thereof include acrylic polymers and the like using one or two or more of linear or branched alkyl esters of several 4 to 18 as monomer components.

  The acrylic polymer may contain units corresponding to other monomer components copolymerizable with the (meth) acrylic acid alkyl ester, if necessary, for the purpose of modifying cohesive force, heat resistance and the like. . Examples of such monomer components include carboxyl group-containing monomers such as acrylic acid, methacrylic acid, carboxyethyl (meth) acrylate, carboxypentyl (meth) acrylate, itaconic acid, maleic acid, fumaric acid, and crotonic acid; maleic anhydride Acid anhydride monomers such as itaconic anhydride; 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate Hydroxyl group-containing monomers such as 8-hydroxyoctyl (meth) acrylate, 10-hydroxydecyl (meth) acrylate, 12-hydroxylauryl (meth) acrylate, (4-hydroxymethylcyclohexyl) methyl (meth) acrylate; The Sulfonic acid groups such as lensulfonic acid, allylsulfonic acid, 2- (meth) acrylamide-2-methylpropanesulfonic acid, (meth) acrylamidepropanesulfonic acid, sulfopropyl (meth) acrylate, (meth) acryloyloxynaphthalenesulfonic acid Containing monomer; Phosphoric acid group-containing monomer such as 2-hydroxyethylacryloyl phosphate; (meth) acrylic acid glycidyl ester, (meth) acrylamide, (meth) acrylic acid N-hydroxymethylamide, (meth) acrylic acid alkylaminoalkyl ester (Eg, dimethylaminoethyl methacrylate, t-butylaminoethyl methacrylate, etc.), N-vinylpyrrolidone, acryloylmorpholine, vinyl acetate, styrene, acrylonitrile; (meth) acrylic Le acid cycloalkyl esters (e.g., cyclopentyl ester and cyclohexyl ester) and the like, such as. One or more of these copolymerizable monomer components can be used. The amount of these copolymerizable monomers used is preferably 70% by weight or less, more preferably 40% by weight or less of the total monomer components.

  Furthermore, since the acrylic polymer is crosslinked, a polyfunctional monomer or the like can be included as a monomer component for copolymerization as necessary. Examples of such polyfunctional monomers include hexanediol di (meth) acrylate, (poly) ethylene glycol di (meth) acrylate, (poly) propylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, Pentaerythritol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol hexa (meth) acrylate, epoxy (meth) acrylate, polyester (meth) acrylate, urethane (meth) Examples include acrylates. These polyfunctional monomers can also be used alone or in combination of two or more. The amount of the polyfunctional monomer used is preferably 70% by weight or less and 30% by weight or less of the total monomer components from the viewpoint of adhesive properties and the like.

  The acrylic polymer can be obtained by subjecting a single monomer or a mixture of two or more monomers to polymerization. The polymerization can be performed by any method such as solution polymerization, emulsion polymerization, bulk polymerization, suspension polymerization and the like. The weight average molecular weight (Mw) of the acrylic polymer is preferably 500,000 to 1,500,000, more preferably 800,000 to 1,200,000. Moreover, it is preferable that the dispersion degree (Mw / Mn) of a weight average molecular weight (Mw) and a number average molecular weight (Mn) is 6-10.

The weight average molecular weight is a value converted by standard polystyrene by the GPC method. As a GPC main body, HLC-8120GPC manufactured by Tosoh Corporation is used, and a data processing using a column temperature of 40 ° C., a pump flow rate of 0.5 ml / min, and a detector RI is performed using a standard polystyrene calibration curve (molecular weight known in advance). (Calibration at 500 to 20.6 million), and the molecular weight was determined from the converted molecular weight.
Column used: TSKgel GMH-H (S) x 2 (Tosoh Corporation)
Mobile phase: Tetrahydrofuran Injection volume: 100 μl
Sample concentration: 1.0 g / l (tetrahydrofuran solution)
The degree of dispersion was calculated as the ratio of the weight average molecular weight to the number average molecular weight. The number average molecular weight was measured by the same method as the weight average molecular weight.

  The polymerizable unsaturated compound is a radiation curable or thermosetting monomer component or oligomer component, and can be cured by an active energy source such as radiation or heat, and has one unsaturated double bond in the molecule. It is a compound having the above. A compound having two or more unsaturated double bonds is preferred. Such a curing component is suitable for controlling the adhesive force so that the cleaning layer does not adhere strongly to the site to be cleaned during transportation, and the viscosity of the system is reduced by adding these monomer components and oligomer components. Therefore, it is possible to expect an effect that the concave structure is more uniformly formed at the time of phase separation.

  The polymerizable unsaturated compound is preferably a non-volatile and low molecular weight material having a weight average molecular weight of 10,000 or less, particularly 5000 or less so that the three-dimensional network of the cleaning layer at the time of curing is efficiently made. It is preferable to have a molecular weight of Specific examples of such a polymerizable unsaturated compound include, for example, phenoxy polyethylene glycol (meth) acrylate, ε-caprolactone (meth) acrylate, polyethylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, 1, 4-butanediol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, 1,6-hexanediol (meth) acrylate, trimethylolpropane tri (meth) acrylate, tetramethylolmethane tetra (meth) acrylate, penta Erythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol monohydroxypenta (meth) acrylate, dipentaerythritol hexa (me ) Acrylates, esterified products of (meth) acrylic acid and polyhydric alcohols such as neopentyl glycol di (meth) acrylate; urethane (meth) acrylate, epoxy (meth) acrylate, oligoester (meth) acrylate, etc. Among these, one type or two or more types are used.

  The blending amount of the polymerizable unsaturated compound (monomer component, oligomer component) is preferably 3 to 100 parts by weight, more preferably 5 to 80 parts by weight, more preferably 10 to 10 parts by weight with respect to 100 parts by weight of the acrylic polymer. 70 parts by weight is preferable, and 10 to 60 parts by weight is more preferable.

  In addition to the additive type described above, the radiation curable or thermosetting acrylic pressure-sensitive adhesive has a carbon-carbon double bond in the polymer side chain or main chain or at the main chain end as a base polymer. Intrinsic type using things. The internal curable pressure-sensitive adhesive does not need to contain an oligomer component, which is a low molecular component, or does not contain many components, so that the oligomer component does not move in the pressure-sensitive adhesive over time, and thus a stable layer. An adhesive layer having a structure can be formed.

  As the base polymer having a carbon-carbon double bond, those having a carbon-carbon double bond and having adhesiveness can be used without particular limitation. As such a base polymer, an acrylic polymer having a basic skeleton is preferable. Examples of the basic skeleton of the acrylic polymer include the acrylic polymers exemplified above.

  The method for introducing a carbon-carbon double bond into the acrylic polymer is not particularly limited. Although various methods can be adopted, the molecular design is easy to introduce the carbon-carbon double bond into the polymer side chain. For example, after a monomer having a functional group is copolymerized in advance with an acrylic polymer, a compound having a functional group capable of reacting with the functional group and a carbon-carbon double bond is converted into a radiation-curable carbon-carbon double bond. And a method of condensation or addition while maintaining the above.

  Examples of combinations of these functional groups include carboxylic acid groups and epoxy groups, carboxylic acid groups and aziridyl groups, hydroxyl groups and isocyanate groups. Among these combinations of functional groups, a combination of a hydroxyl group and an isocyanate group is preferable because of easy reaction tracking. In addition, the functional group may be on either side of the acrylic polymer and the compound as long as the acrylic polymer having the carbon-carbon double bond is generated by a combination of these functional groups. In the preferable combination, it is preferable that the acrylic polymer has a hydroxyl group and the compound has an isocyanate group. In this case, examples of the isocyanate compound having a carbon-carbon double bond include methacryloyl isocyanate, 2-methacryloyloxyethyl isocyanate, m-isopropenyl-α, α-dimethylbenzyl isocyanate, and the like. As the acrylic polymer, those obtained by copolymerization of the above-exemplified hydroxy group-containing monomers, ether compounds of 2-hydroxyethyl vinyl ether, 4-hydroxybutyl vinyl ether, diethylene glycol monovinyl ether, or the like are used.

  As the intrinsic curable pressure-sensitive adhesive, the base polymer (acrylic polymer) having the carbon-carbon double bond can be used alone, but the curable monomer component and oligomer component to the extent that the characteristics are not deteriorated. Can also be blended. In the case of an internal type curable pressure-sensitive adhesive, it is preferable that the base polymer having the carbon-carbon double bond is contained in an amount of 40% by weight or more, more preferably 50% by weight or more.

  Moreover, in order to accelerate | stimulate bridge | crosslinking of the acrylic polymer which is a base polymer, an external crosslinking agent can also be suitably added to the said adhesive as needed. As the kind of the crosslinking agent, for example, a polyfunctional compound capable of reacting with this functional group is preferable for an acrylic polymer having a carboxyl group or a hydroxyl group. For example, polyisocyanates such as diphenylmethane diisocyanate and tolylene diisocyanate, epoxy compounds, aziridine compounds, melamine-based crosslinking agents, urea resins, anhydrous compounds, polyamines, carboxyl group-containing polymers, various metal salts, chelate compounds, and so-called crosslinking agents are added. And reacting them. The amount of these crosslinking agents (polyfunctional compounds) used is within a range of 20 parts by weight or less, further 0.01 to 20 parts by weight, 0.01 to 10 parts by weight with respect to 100 parts by weight of the acrylic polymer. It is preferable to mix. There is no problem even if these crosslinking agents are used alone or in combination of two or more.

  The curable acrylic pressure-sensitive adhesive can contain an initiator depending on the curing method. When the curable adhesive is cured by ultraviolet rays or the like, a photopolymerization initiator is included. Examples of the photopolymerization initiator include 4- (2-hydroxyethoxy) phenyl (2-hydroxy-2-propyl) ketone, α-hydroxy-α, α′-dimethylacetophenone, 2-methyl-2-hydroxypropio Α-ketol compounds such as phenone and 1-hydroxycyclohexyl phenyl ketone; methoxyacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxyacetophenone, 2-methyl-1- [4- ( Acetophenone compounds such as methylthio) -phenyl] -2-morpholinopropane-1; benzoin ether compounds such as benzoin ethyl ether, benzoin isopropyl ether and anisoin methyl ether; ketal compounds such as benzyldimethyl ketal; 2-naphthalenesulfo D Aromatic sulfonyl chloride compounds such as luchloride; Photoactive oxime compounds such as 1-phenone-1,1-propanedione-2- (o-ethoxycarbonyl) oxime; benzophenone, benzoylbenzoic acid, 3,3′-dimethyl Benzophenone compounds such as -4-methoxybenzophenone; thioxanthone, 2-chlorothioxanthone, 2-methylthioxanthone, 2,4-dimethylthioxanthone, isopropylthioxanthone, 2,4-dichlorothioxanthone, 2 Thioxanthone compounds such as 1,4-diethylthioxanthone and 2,4-diisopropylthioxanthone; camphorquinone; halogenated ketone; acyl phosphinoxide; acyl phosphonate. The compounding quantity of a photoinitiator is about 0.1-10 weight part with respect to 100 weight part of base polymers, such as an acryl-type polymer which comprises an adhesive, Preferably it is 0.5-5 weight part.

  If necessary, additives such as various conventionally known tackifiers, anti-aging agents, fillers, colorants, chain transfer agents, and plasticizers may be used for the pressure-sensitive adhesive.

  The method for forming the pressure-sensitive adhesive layer of the present invention is not particularly limited as long as it is a method capable of forming a pressure-sensitive adhesive layer having discontinuous recesses on the surface as described above, but radiation curable containing the acrylic polymer. Or it can carry out by performing the said process (1) thru | or (3) to a thermosetting acrylic adhesive.

  In the step (1), a pressure-sensitive adhesive composition containing an acrylic polymer-containing radiation-curable or thermosetting acrylic pressure-sensitive adhesive and a compound that is not compatible with the acrylic polymer is added to the acrylic polymer. A pressure-sensitive adhesive composition solution dissolved in a mixed solvent containing a solvent (A) that dissolves the solvent and a compatibilizing solvent (B) that compatibilizes both the acrylic polymer and the incompatible compound is applied onto the substrate. Then, the pressure-sensitive adhesive composition layer is formed by drying.

  The incompatible compound is an additive having low compatibility with the acrylic pressure-sensitive adhesive for forming a recess on the surface of the pressure-sensitive adhesive layer. The incompatible compound is not particularly limited as long as it can be mixed with the acrylic pressure-sensitive adhesive and can be phase-separated when the pressure-sensitive adhesive composition layer is formed. Since the pressure-sensitive adhesive composition is used as a solution, it is preferable that the pressure-sensitive adhesive composition is phase-separated in the solvent removal process after being applied to a substrate. The degree of phase separation of the incompatible compound is preferably one that forms a liquid phase separation state in the liquid state with the acrylic pressure-sensitive adhesive (solution).

As the incompatible compound, a compound having a low boiling point that is not compatible with the acrylic pressure-sensitive adhesive and does not volatilize when the solvent is dried is used. For example, regarding the compatibility, when the χ parameter for the acrylic polymer is 7 or more, it is easy to phase separate from the acrylic pressure-sensitive adhesive and to form a phase separated structure. When the χ parameter is 7 or less, phase separation hardly occurs, and a slight change in composition affects the phase separation. Therefore, it is easily affected by solvent drying conditions, and it is difficult to form a stable structure. The χ parameter is preferably 7.5 or more, more preferably 8 or more. The χ parameter is an interaction constant based on the Flory-Huggins theory and is defined by χ parameter = (V ₁ / RT) × (δ ₁ −δ ₂ ) ² . V ₁ : molar volume, R: gas constant, T: absolute temperature, δ: solubility parameter. When the mixed solvent is dried at around 50 to 60 ° C., if the incompatible compound has a boiling point of 190 ° C. or higher, a phase separation structure is formed without volatilization during solvent drying. can do. The boiling point of the incompatible compound is preferably 200 ° C. or higher, and more preferably 200 to 300 ° C.

  Examples of the incompatible compound include ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, and polypropylene glycol, and their one-end or both-end methyl capped compounds, one piece Glycol compounds such as terminal or both-end (meth) acrylate clogged materials are listed as examples, and one or more of them can be selected and used.

  The amount of the incompatible compound is usually 3 to 200 parts by weight with respect to a total of 100 parts by weight of the acrylic polymer and the polymerizable unsaturated compound in the case of an addition-type curable acrylic pressure-sensitive adhesive. It is preferable to do this. The blending amount is preferably 100 parts by weight or less, and more preferably 50 parts by weight or less in order to optimize the size of the formed recess. On the other hand, 5 parts by weight or more is preferable in order to achieve phase separation at a level at which the recesses are developed.

  The pressure-sensitive adhesive composition solution can be prepared by mixing the incompatible compound through the acrylic pressure-sensitive adhesive and a solvent. Examples of the solvent include a mixed solvent containing a solvent (A) for dissolving the acrylic polymer used for the acrylic pressure-sensitive adhesive and a compatibilizing solvent (B) for compatibilizing both the acrylic polymer and the incompatible compound. Used.

  The solvent (A) is appropriately determined according to the type of the acrylic polymer so that it can uniformly dissolve the acrylic polymer. When the solvent (A) is represented by a χ parameter which is an index of solubility, it is preferable to use a solvent having a χ parameter of 3 or less for an acrylic polymer. If the χ parameter exceeds 3, it may be difficult to dissolve the acrylic polymer. More preferably, the χ parameter is 0.34 to 2.8.

  Examples of the solvent (A) include butane, hexane, heptane, toluene, o-xylene, m-xylene, p-xylene, cyclohexane, diethyl ether, isopropyl ether, dibutyl ether, dibenzyl ether, tetrahydrofuran, acetone, and methyl ethyl ketone. , Methyl isobutyl ketone, 2-heptanone (methylpentyl ketone), diisobutyl ketone, cyclohexanone (anone), methylcyclohexanone, cyclopentanone, amyl acetate, methyl acetate, ethyl acetate, propyl acetate, butyl acetate, N, N-dimethylformamide (DMF), N, N-dimethylacetamide (DMAc), N-methylpyrrolidone and the like. As the organic solvent, ethyl acetate, toluene, xylene and the like are preferable.

  On the other hand, as the compatibilizing solvent (B), a solvent that is compatible with both the acrylic polymer and the incompatible compound and that is compatible with the solvent (A) is used. The compatibilizing solvent (B) has a χ parameter of 0.5 to 3, preferably 0.5 to 2.8 with respect to the acrylic polymer, and preferably 0.5 to 3 with respect to the incompatible compound. Is preferably 0.5 to 2.8. When the χ parameter of the compatibilizing solvent (B) is out of the above range, the acrylic pressure-sensitive adhesive and the incompatible compound may not be uniformly dispersed in the solution as the pressure-sensitive adhesive composition solution.

  The compatibilizing solvent (B) is appropriately selected according to the type of acrylic polymer, incompatible compound, and solvent (A). As the compatibilizing solvent (B), for example, an alcohol solvent is suitable. Examples of the alcohol solvent include methanol, ethanol, isopropyl alcohol, 1-pentanol, cyclohexanol, 2-methylcyclohexanol, 2-methoxyethanol, 2-ethoxyethanol, 2-butoxyethanol and the like. Of these, methanol and ethanol are preferred.

  The mixing ratio of the solvent (A) and the compatibilizing solvent (B) is not particularly limited as long as the acrylic polymer, the polymerizable unsaturated compound, and the incompatible compound can be uniformly mixed. Usually, the solvent (A) / the compatibilizing solvent is used. (B) = 1/3 to 3/1 (weight ratio) is preferable. When the value of the solvent (A) / the compatibilizing solvent (B) is 1/3 or less or 3/1 or more, uniform mixing may not be possible, and the pressure-sensitive adhesive layer cannot form a uniform concave structure. There is a case. The pressure-sensitive adhesive composition is usually adjusted to a solution having a solid content concentration of 5 to 50% by weight, preferably 5 to 30% by weight, and more preferably 10 to 25% by weight, with the mixed solvent.

  The pressure-sensitive adhesive composition solution becomes a uniform state by using a mixed solvent of the solvent (A) and the compatibilizing solvent (B), but phase separation occurs in the absence of the compatibilizing solvent (B). Solvent (A) is preferred. Use of such a solvent (A) is preferable in forming a phase separation structure of the acrylic pressure-sensitive adhesive and the incompatible compound in the step (2).

  The said adhesive composition solution is apply | coated on a support body, and the said adhesive composition layer is formed by drying the said solvent. Various methods can be adopted as the forming method. For example, when a continuous coating apparatus is used for forming the pressure-sensitive adhesive composition layer, for example, the pressure-sensitive adhesive composition solution is continuously supplied, and the sheet base is continuously formed by a discharge means such as a die attached to the front end of the apparatus. The method of extruding to a thin layer on a material is mentioned. In addition, when the batch method is adopted as a method for forming the pressure-sensitive adhesive composition layer, the pressure-sensitive adhesive composition solution is cast on a substrate and molded with an applicator, a Meyer bar, or a knife coater. The method of doing is mentioned. Thus, after laminating | stacking the thinned adhesive composition on a support body, it heats and removes a solvent. By drying the solvent, the incompatible compound is insolubilized in the acrylic pressure-sensitive adhesive composition and phase-separated to form a very fine concave structure on the surface. The drying temperature of the mixed solvent is not particularly limited, but is preferably about 50 to 60 ° C.

  Although the thickness of the said adhesive composition layer is not specifically limited, Usually, about 5-100 micrometers, Furthermore, it is preferable that it is 10-50 micrometers. When it is thinner than this, the shape following property of the pressure-sensitive adhesive layer may be lowered, and the foreign matter collecting property may be lowered. In addition, if it exceeds this, the substrate may be too thick and difficult to handle.

  The said base material can be used also as a support body of the adhesive sheet which provided the adhesive layer obtained. The base material that can be such a support is not particularly limited. For example, polyolefin resins such as polyethylene and polypropylene, polyester resins such as polyethylene terephthalate, cellulose resins such as acetylcellulose, polycarbonate resins, and polyamide resins. And plastic sheets such as polyimide resins, polycarbodiimide resins, and vinyl chloride resins. The thickness of the substrate is usually preferably about 10 to 300 μm. Further, the thickness is preferably about 30 to 200 μm from the viewpoint of handling. In addition, when using a radiation curable adhesive for formation of an adhesive layer, the plastic sheet which permeate | transmits light, such as an ultraviolet-ray, is selected and used. Moreover, as a base material, you may use metal foil depending on the case. These substrates may be subjected to various surface treatments on the surface.

  Next, in the step (2), the pressure-sensitive adhesive composition layer is irradiated or heated to cure the acrylic pressure-sensitive adhesive, and has a phase separation structure of the cured product and the incompatible compound. A layer precursor is formed.

  In the irradiation or heating of the pressure-sensitive adhesive composition layer formed on the substrate, the acrylic pressure-sensitive adhesive is cured, the oxygen inhibition of crosslinking is suppressed, and the flat surface on which the concave portion is formed is made smoother. The surface of the pressure-sensitive adhesive composition layer is preferably subjected to a curing treatment while being covered with a cover film. As a result, a decrease in the degree of cure and the degree of crosslinking due to oxygen inhibition during curing of the acrylic pressure-sensitive adhesive can be suppressed, and when a convex portion is generated on the phase-separated surface by using the cover film, the portion is flattened. effective.

  The cover film is not particularly limited, and examples thereof include plastic films such as polyethylene, polypropylene, polyethylene terephthalate, acetyl cellulose, polycarbonate, polyamide, and polycarbodiimide. The thickness is usually preferably about 10 to 100 μm. When a radiation curable pressure sensitive adhesive is used for forming the pressure sensitive adhesive layer, a relatively transparent plastic film that transmits light such as ultraviolet rays is selectively used. As a cover film, various peeling processing may be given to the surface which faces the adhesive, and it is also possible to use it as a peeling film normally used.

  The acrylic pressure-sensitive adhesive is irradiated or heated depending on its curability. Examples of radiation include ultraviolet rays and electron beams. As a curing method, ultraviolet curing is preferable from the viewpoint of the process. Thereby, the concave structure formed on the substrate is fixed. In addition, the acrylic pressure-sensitive adhesive and the incompatible compound may be further phase-separated by reaction-induced phase separation at the time of curing, and the concave structure may be enlarged. Is 0.1 to 3 μm, the standard deviation of the opening diameter is 0.7 μm or less, and the distribution of the openings is in the range where the standard deviation of the center-to-center distance between adjacent openings is 1 μm or less. To control. There is no problem even if the incompatible compound is partially crosslinked with the acrylic pressure-sensitive adhesive (acrylic polymer or polymerizable unsaturated compound) in the curing process of the acrylic pressure-sensitive adhesive.

  Next, in step (3), the incompatible compound is removed from the obtained pressure-sensitive adhesive layer precursor. For example, as the step (3), the incompatible compound can be removed from the pressure-sensitive adhesive layer precursor by heating. Moreover, an incompatible compound can be removed from the pressure-sensitive adhesive layer precursor by solvent extraction. Thereby, a recessed part can be formed in the adhesive layer surface.

  As a method for removing the incompatible compound by heating, a general heating apparatus can be applied. Examples thereof include a heat convection dryer, a heat circulation dryer, a vacuum dryer, a floating oven, a hot air circulation oven, and the like. The heating temperature is not particularly limited as long as the base material or the concaved adhesive layer is not deformed by heat in consideration of the boiling point of the incompatible compound, the scattering temperature, etc., but is usually about 50 to 200 ° C., more preferably 100 to A range of about 200 ° C. is preferable in that it can be efficiently removed.

  In addition, when the incompatible compound is extracted and removed from the pressure-sensitive adhesive layer precursor by a solvent, the solvent used for extraction of the incompatible compound is properly used depending on the type of the acrylic pressure-sensitive adhesive layer forming the matrix and the incompatible compound, An organic solvent that can extract an incompatible compound from the pressure-sensitive adhesive layer is generally used. Examples of such a solvent include toluene, ethyl acetate and the like.

  In addition, non-toxic and non-dangerous liquefied carbon dioxide or supercritical carbon dioxide can be used in place of the organic solvent. The container for removing the incompatible compound with carbon dioxide is not particularly limited as long as it is a container that can be extracted and removed under pressure, such as a batch-type pressure container, a sheet feeding device having pressure resistance, and a winding device. Either may be sufficient. The means for supplying carbon dioxide, which is an inert fluid, can be constituted by a pump, piping, a valve, and the like.

  As shown in FIG. 3, the pressure-sensitive adhesive layer 1 of the present invention obtained as described above is provided as a pressure-sensitive adhesive sheet on at least one surface of the support 2 so that the discontinuous recesses are on the surface. Can do. As the support 2, the substrate in the production method can be used as it is.

  The pressure-sensitive adhesive sheet can be used as a cleaning sheet in which the pressure-sensitive adhesive layer 1 is provided as a cleaning layer on at least one surface of the support 2. The cleaning sheet can be used as a label sheet. When the pressure-sensitive adhesive sheet is used as a cleaning sheet, as shown in FIG. 4, a fixing pressure-sensitive adhesive layer 3 is provided on the other surface of the support 2 provided with the pressure-sensitive adhesive layer 1 having the recesses. be able to.

  The material of the fixing pressure-sensitive adhesive layer 3 is not particularly limited as long as it satisfies a normal pressure-sensitive adhesive function, and a normal pressure-sensitive adhesive (for example, acrylic or rubber-based) can be used. The pressure-sensitive adhesive layer 3 can be a double-sided tape. The pressure-sensitive adhesive layer 3 is cleaned by attaching a cleaning sheet to a transport member such as various substrates or other tapes and sheets, transporting the cleaning sheet into the apparatus as a transport member with a cleaning function, and bringing it into contact with the site to be cleaned. Can do.

  The transport member to which the cleaning sheet is attached is not particularly limited, and examples thereof include semiconductor wafers, substrates for flat panel displays such as LCDs and PDPs, and other substrates such as compact disks and MR heads.

  In order to reuse the transporting member such as the substrate, the pressure-sensitive adhesive layer 3 is preferably easily peelable from the substrate when the substrate is peeled off from the pressure-sensitive adhesive layer 3 after cleaning. . The adhesive strength of the pressure-sensitive adhesive layer 3 is to be peeled off during transportation if the 180 ° peel-off adhesive strength to the silicon wafer (mirror surface) is 0.01 to 10 N / 10 mm, especially about 0.10 to 5 N / 10 mm. This is preferable because it can be easily removed after cleaning.

  The conveying member with a cleaning function is preferably configured such that the shape of the cleaning sheet is smaller than the shape of the conveying member and does not protrude from the end of the conveying member. If the cleaning sheet is larger than the shape of the conveying member, the sheet may adhere to the apparatus inside the conveying apparatus or get caught by the conveying system, and the apparatus may not operate normally.

  The manufacturing method of the conveyance member with a cleaning function as described above is not particularly limited. For example, a cleaning conveyance member can be manufactured by attaching a cleaning sheet to a conveyance member such as a substrate. In this case, after a cleaning sheet that is larger than the conveying member is pasted, the cleaning sheet is cut along the shape of the member (hereinafter referred to as the direct cut method), or cleaning that has been cut into the conveying member shape in advance. And a method of manufacturing a cleaning conveying member by attaching the label sheet to the conveying member (hereinafter referred to as a pre-cut method).

  Hereinafter, although the present invention is explained based on an example, the present invention is not limited to these. Hereinafter, “parts” means parts by weight. Mw means the weight average molecular weight, Mn means the number average molecular weight, and Mw / Mn means the degree of dispersion of the molecular weight of the polymer.

Example 1
(Preparation of UV curable acrylic adhesive)
Acrylic polymer (Mw about 850,000, Mw / Mn is 9) obtained from a monomer mixture consisting of 70 parts of butyl acrylate, 30 parts of ethyl acrylate, 1 part of acrylic acid and 5 parts of 2-hydroxyethyl acrylate For 100 parts, 40 parts polyfunctional urethane acrylate (manufactured by Nippon Synthetic Chemical Co., Ltd .: trade name: UV1700B) as the polymerizable unsaturated compound, and polyisocyanate compound (manufactured by Nippon Polyurethane Industry Co., Ltd .: trade name: coronate) as the crosslinking agent 2 parts of L) and 1 part of a polyepoxy compound (manufactured by Mitsubishi Gas Chemical Company, Inc .: trade name: Tetrad C), 3 parts of a photopolymerization initiator (Irgacure 651: manufactured by Ciba Specialty Chemicals Co., Ltd.) are added, and a solvent is further added. (A) ethyl acetate (χ parameter for the acrylic polymer: 0.53, heavy Χ parameter for the unsaturated compound: 8.7) and methanol as the compatibilizing solvent (B) (χ parameter for the acrylic polymer: 2.0, χ parameter for the polymerizable unsaturated compound: 2.7), An ultraviolet curable acrylic pressure-sensitive adhesive solution was prepared by uniformly mixing with a mixed solvent blended at a ratio of solvent (A) / solvent (B) = 12/7 and adjusting the concentration to 18% by weight.

(Preparation of UV-curable acrylic pressure-sensitive adhesive composition)
In the pressure-sensitive adhesive solution, glycerin (χ parameter for the acrylic polymer A) as an incompatible compound for phase separation with respect to a total of 100 parts (solid content) of the acrylic polymer and polymerizable unsaturated compound contained in the solution : 10, boiling point 290 ° C.) 10 parts were uniformly mixed to prepare an ultraviolet curable acrylic pressure-sensitive adhesive composition solution.

(Preparation of adhesive sheet)
The pressure-sensitive adhesive composition solution was applied to one side of a polyester film for a support having a width of 200 mm and a thickness of 50 μm so that the thickness after drying was 35 μm, and dried at 55 ° C. for 4 minutes. A pressure-sensitive adhesive composition layer having recesses was formed. Next, a 50 μm thick polyester-based release film is applied to the surface of the pressure-sensitive adhesive composition layer, then irradiated with ultraviolet rays, the acrylic pressure-sensitive adhesive is cured, and the structure of the recesses is fixed to have a phase separation structure. An adhesive layer precursor was formed. Thereafter, the polyester-based release film was removed, and heated at 150 ° C. for 10 minutes to remove glycerin forming concave portions, thereby obtaining the pressure-sensitive adhesive sheet of the present invention. The pressure-sensitive adhesive sheet was kept at 50 ° C. for 72 hours to age the pressure-sensitive adhesive layer.

(Cleaning sheet)
The adhesive sheet was used as a cleaning sheet. Also, the adhesive film is applied to the side of the support sheet of the cleaning sheet where the adhesive layer (cleaning layer) is not provided, so that the thickness after drying is 20 μm, and the adhesive for fixing A cleaning sheet was prepared by providing a layer and bonding a polyester release film to the surface. Furthermore, the pressure-sensitive adhesive layer for fixing was heated at 50 ° C. for 72 hours to age the pressure-sensitive adhesive layer.

  The fixing adhesive solution was prepared by the following method. A three-neck flask type reactor having a 500 ml internal volume equipped with a thermometer, a stirrer, a nitrogen introduction tube and a reflux condenser was added to 73 parts of 2-ethylhexyl acrylate, 10 parts of n-butyl acrylate, N, N- 15 parts of dimethylacrylamide and 5 parts of acrylic acid, 0.15 part of 2,2-azobisisobutyronitrile as a polymerization initiator, and 100 parts of ethyl acetate were added in a total amount of 200 g. After stirring for about 1 hour, the air inside was replaced with nitrogen. Thereafter, the internal temperature was set to 58 ° C., and the polymerization was carried out in this state for about 4 hours to obtain an acrylic polymer solution. To 100 parts of the acrylic polymer solution, 3 parts of a polyisocyanate compound (manufactured by Nippon Polyurethane Industry Co., Ltd .: trade name: Coronate L) was uniformly mixed to obtain an adhesive solution for fixing.

Example 2
(Preparation of UV curable acrylic adhesive)
In Example 1, an ultraviolet curable acrylic pressure-sensitive adhesive was used in the same manner as in Example 1 except that a mixed solvent having a ratio of solvent (A) / solvent (B) = 7/12 was used. A solution was prepared.

(Preparation of UV-curable acrylic pressure-sensitive adhesive composition)
In the pressure-sensitive adhesive solution, glycerin (χ parameter for the acrylic polymer as an incompatible compound for phase separation) with respect to a total of 100 parts (solid content) of the acrylic polymer and the polymerizable unsaturated compound contained in the solution. (10, boiling point 290 ° C.) 10 parts were mixed uniformly to prepare an ultraviolet curable acrylic pressure-sensitive adhesive composition solution.

  Thereafter, an adhesive sheet and a cleaning sheet were produced in the same manner as in Example 1 except that the adhesive composition solution prepared above was used.

Example 3
(Preparation of UV-curable acrylic pressure-sensitive adhesive composition)
In the pressure-sensitive adhesive solution prepared in Example 1, 100 parts (solid content) of the acrylic polymer and the polymerizable unsaturated compound contained in the solution are 1, 2, 2, as incompatible compounds for phase separation. 25 parts of 3-butanetriol (χ parameter for the acrylic polymer: 8.8) were uniformly mixed to prepare an ultraviolet curable acrylic pressure-sensitive adhesive composition solution.

  Thereafter, an adhesive sheet and a cleaning sheet were produced in the same manner as in Example 1 except that the adhesive composition solution prepared above was used.

Comparative Example 1
(Preparation of UV curable acrylic adhesive)
In Example 1, instead of the mixed solvent, only the solvent (A), ethyl acetate, was used, and the concentration was adjusted to 18% by weight. A solution of the agent was prepared.

(Preparation of UV-curable acrylic pressure-sensitive adhesive composition)
In the pressure-sensitive adhesive solution, glycerin (χ parameter for the acrylic polymer as an incompatible compound for phase separation) with respect to a total of 100 parts (solid content) of the acrylic polymer and the polymerizable unsaturated compound contained in the solution. When 10 parts (10, boiling point 290 ° C.) were added, phase separation occurred and a uniform solution could not be prepared. As a result, an adhesive sheet and a cleaning sheet could not be produced.

Comparative Example 2
(Preparation of UV curable acrylic adhesive)
In Example 1, the amount of polyfunctional urethane acrylate which is a polymerizable unsaturated compound (manufactured by Nippon Synthetic Chemical Co., Ltd .: trade name: UV1700B) is changed to 80 parts, and acetic acid which is the solvent (A) is used instead of the mixed solvent. A solution of an ultraviolet curable acrylic pressure-sensitive adhesive was prepared in the same manner as in Example 1 except that the concentration was adjusted to 18% by weight using only ethyl.

(Preparation of UV-curable acrylic pressure-sensitive adhesive composition)
In the pressure-sensitive adhesive solution, 1,3-propanediol (the acrylic resin) is used as an incompatible compound for phase separation with respect to 100 parts (solid content) of the acrylic polymer and polymerizable unsaturated compound contained in the solution. 10 parts of χ parameter for the polymer: 5.6, boiling point 214 ° C.) were uniformly mixed to prepare a solution of an ultraviolet curable acrylic pressure-sensitive adhesive composition.

  Thereafter, an adhesive sheet and a cleaning sheet were produced in the same manner as in Example 1 except that the adhesive composition solution prepared above was used.

  The following evaluation was performed about the adhesive layer obtained by the Example and the comparative example. The results of Examples 1 to 3 and Comparative Example 2 are shown in FIGS.

(Average opening diameter and standard deviation of the opening of the recess)
The image observed with the scanning electron microscope was subjected to image analysis with image analysis software, and the average diameter of the recesses was calculated. This average diameter was defined as the average opening diameter. In addition, a standard deviation was calculated for the opening diameter.

(Uniformity)
The image observed with the scanning electron microscope was image-analyzed with image analysis software, the center-to-center distance between adjacent openings was calculated, and the standard deviation was calculated.

(Concavity projection area)
The surface of the pressure-sensitive adhesive layer was photographed with a scanning electron microscope (manufactured by Hitachi, Ltd., S570), and the area ratio of the recesses on the surface of the pressure-sensitive adhesive layer was calculated by image analysis.

(Depth of recess)
The concave portion of the pressure-sensitive adhesive layer was frozen and broken in liquid nitrogen, the cross section was observed with the scanning electron microscope, and h / H was calculated from the depth h of the concave portion in the cross section and the thickness H in the cross section.

  The scanning microscope images of the pressure-sensitive adhesive layers obtained in Examples 1 to 3 correspond to FIGS. 5 to 8 respectively. Each of FIG. 5 to FIG. 8A is an image from the upper surface of the pressure-sensitive adhesive layer surface, and each (B) is a cross-sectional image. The black part in the figure is a recess. From FIG. 5 thru | or FIG. 8, it turns out that the surface of an adhesive layer is planar and has a recessed part.

  Moreover, the following evaluation was performed about the adhesive sheet and cleaning sheet obtained by the Example and the comparative example. The results are shown in Table 1.

(Vertical peeling force)
A metal piece having a diameter of 50 mm was brought into close contact with the cleaning layer under a load of 2 kg for 3 minutes, and the peeling force applied when the metal piece was lifted vertically at a pulling speed of 100 mm / min at a room temperature of 23 ° C. was measured.

(Transportability)
The sample was transferred into a substrate processing apparatus (device name: GR-3000, manufactured by Nitto Seiki Co., Ltd.) having a wafer stage and evaluated according to the following criteria.
X: When there is adhesion to each part or stage, or when the transfer device is stopped.
Δ: The transfer device did not stop, but a sound was produced when peeling from each part and stage.
○: When the transport device does not stop and no sound is generated when peeling from each part and stage.

(Foreign matter collection)
The release film on the pressure-sensitive adhesive layer side for fixing the cleaning sheet was peeled off, and the pressure-sensitive adhesive layer was attached to the back surface (mirror surface) of an 8-inch silicon wafer with a hand roller to produce a cleaning cleaning wafer with a cleaning function. . Next, the wafer was placed several times on the stage of a substrate processing apparatus (apparatus name: GR-3000, manufactured by Nitto Seiki Co., Ltd.) having a wafer stage, and simulated foreign substances were adhered. The simulated foreign substances are polishing scraps of the wafer, and about 10,000 to 20,000 particles having a size of 1.7 μm or more (upper limit of 600 μm) were deposited on the stage. After the 8-inch silicon wafer was transferred to the substrate processing apparatus with the mirror surface facing downward for initial contamination state evaluation, the mirror surface was measured with a laser type foreign matter measuring device to measure the initial foreign matter amount (8 inch wafer). Within the size area). The cleaning wafer with a cleaning function was transferred three times to the substrate processing apparatus with the cleaning surface facing downward. The amount of foreign matter after conveyance was measured with a laser type foreign matter measuring device (Laser type particle counter, manufactured by TENCOR, SURFSCAN6200), and (initial foreign matter amount−collected foreign matter amount after transportation) / initial foreign matter amount was calculated. If this ratio was 30% or more, it was determined as “◯”. The case of less than 30% was defined as “x”.

It is an example of the perspective view of the adhesive layer of this invention. It is an example of sectional drawing of the adhesive layer of this invention. It is an example of sectional drawing of the adhesive sheet (cleaning sheet) of the adhesive layer of this invention. It is an example of sectional drawing of the adhesive sheet (cleaning sheet) of the adhesive layer of this invention. 2 is a top image of the pressure-sensitive adhesive layer obtained in Example 1. FIG. 2 is a cross-sectional image of the pressure-sensitive adhesive layer obtained in Example 1. FIG. 4 is a top image of the pressure-sensitive adhesive layer obtained in Example 2. FIG. 2 is a cross-sectional image of a pressure-sensitive adhesive layer obtained in Example 2. 3 is a top image of the pressure-sensitive adhesive layer obtained in Example 3. FIG. 3 is a cross-sectional image of a pressure-sensitive adhesive layer obtained in Example 3. 3 is a top image of the pressure-sensitive adhesive layer obtained in Comparative Example 2. 3 is a cross-sectional image of a pressure-sensitive adhesive layer obtained in Comparative Example 2.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Adhesive layer which has a recessed part 2 Support body 3 Adhesive layer for fixation a Recessed part

Claims (18)

A cleaning layer using a pressure-sensitive adhesive layer having a planar surface, comprising a cured product of a radiation-curable or thermosetting acrylic pressure-sensitive adhesive containing an acrylic polymer,
Having discontinuous recesses on the surface of the pressure-sensitive adhesive layer, and
The opening of the recess is substantially circular, and the average opening diameter is 0.1 to 3 μm,
The standard deviation of the opening diameter is 0.7 μm or less,
The cleaning layer is characterized in that the distribution of the openings is such that the standard deviation of the center-to-center distance between adjacent openings is 1 μm or less. The cleaning layer according to claim 1, wherein a ratio of a projected area of the discontinuous recesses to a total projected area of the surface of the pressure-sensitive adhesive layer is 15% to 80%. The ratio (h / H) of the depth (h) of the recess to the thickness (H) of the pressure-sensitive adhesive layer is 0.01 to 0.1. Cleaning layer. The cleaning layer according to claim 1, wherein the radiation curable or thermosetting acrylic pressure-sensitive adhesive contains an acrylic polymer and a polymerizable unsaturated compound. It is a manufacturing method of the cleaning layer in any one of Claims 1-4,
A pressure-sensitive adhesive composition containing an acrylic polymer-containing radiation-curable or thermosetting acrylic pressure-sensitive adhesive and a compound that is not compatible with the acrylic polymer is used as a solvent for dissolving the acrylic polymer (A ) And a pressure-sensitive adhesive composition solution dissolved in a mixed solvent containing a compatibilizing solvent (B) that compatibilizes both the acrylic polymer and the incompatible compound is applied onto a substrate and dried. (1) forming an adhesive composition layer by
A step of forming a pressure-sensitive adhesive layer precursor having a phase separation structure of the cured product and the incompatible compound while curing the acrylic pressure-sensitive adhesive by irradiating or heating the pressure-sensitive adhesive composition layer ( 2) and
A process for producing a cleaning layer, comprising a step (3) of removing an incompatible compound from the obtained pressure-sensitive adhesive layer precursor. The compatibilizing solvent (B), which is compatible with both the acrylic polymer and the incompatible compound, has a χ parameter, which is a compatibility parameter, of 0.5 to 3 with respect to the acrylic polymer. 6. The method for producing a cleaning layer according to claim 5, wherein the ratio is 0.5 to 3 with respect to the dissolved compound. The method for producing a cleaning layer according to claim 5 or 6, wherein the incompatible compound has a χ parameter of 7 or more for an acrylic polymer and a boiling point of 190 ° C or more. The pressure-sensitive adhesive composition solution is in a uniform state, but the solvent (A) and the compatibilizing solvent (B) are selected so that phase separation occurs in the absence of the compatibilizing solvent (B). A method for producing a cleaning layer according to any one of claims 5 to 7. The method for producing a cleaning layer according to any one of claims 6 to 8, wherein the compatibilizing solvent (B) is an alcohol solvent. The said process (3) removes an incompatible compound from an adhesive layer precursor by heating, The manufacturing method of the cleaning layer in any one of Claims 5-9 characterized by the above-mentioned. The method for producing a cleaning layer according to claim 5, wherein the step (3) removes an incompatible compound from the pressure-sensitive adhesive layer precursor by solvent extraction. The method for producing a cleaning layer according to claim 11, wherein the solvent used for the solvent extraction is liquefied carbon dioxide or carbon dioxide in a supercritical state. The method for producing a cleaning layer according to any one of claims 5 to 12, wherein in the step (2), the surface of the pressure-sensitive adhesive composition layer is irradiated with radiation or heated while being covered with a cover film. A pressure-sensitive adhesive sheet, wherein the cleaning layer according to any one of claims 1 to 4 is provided on at least one side of a support so that the discontinuous recesses are on the surface. Cleaning layer according according to any one of claims 1 to 4, as a discontinuous concave of the pressure-sensitive adhesive layer to be used in the cleaning layer is on the surface, is eclipsed set on one side with the least of the support A cleaning sheet characterized by comprising: Cleaning layer according to any one of claims 1-4, as a discontinuous concave of the pressure-sensitive adhesive layer to be used in the cleaning layer is on the surface, are eclipsed set to one side of a support, the other one side Has a fixing pressure-sensitive adhesive layer.   A conveying member with a cleaning function, wherein the cleaning sheet according to claim 16 is provided on the conveying member via a fixing adhesive layer.   A cleaning method for a substrate processing apparatus, comprising transporting the cleaning sheet according to claim 15 or 16 or the transport member with a cleaning function according to claim 17 into the substrate processing apparatus.