Cleaning sheet and carrying member with cleaning function

Abstract

To provide a cleaning sheet that is excellent in foreign substance removal performance and that prevents detachment of a cleaning layer.SOLUTION: The cleaning sheet according to an embodiment of the present invention includes a cleaning layer, the cleaning layer including a polyimide resin including a structural unit having an alicyclic skeleton, the polyimide resin including a structural unit derived from a tetracarboxylic dianhydride with an alicyclic skeleton.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a cleaning sheet and a conveying member with cleaning function. [Background technology]

[0002] In various substrate processing equipment that is sensitive to foreign matter, such as manufacturing equipment and inspection equipment for semiconductors, flat panel displays, and printed circuit boards, substrates are transported while being in physical contact with a transport device (typically a chuck table, etc.). In this case, if foreign matter adheres to the transport device, it will contaminate subsequent substrates, requiring the equipment to be periodically stopped and cleaned. This results in problems such as a decrease in the operating rate of the processing equipment and the great effort required to clean the equipment.

[0003] To overcome this problem, a method has been proposed in which foreign matter adhering to the transport device is removed by transporting a plate-like member into the substrate processing apparatus (see Patent Document 1). This method eliminates the need to stop the substrate processing apparatus to perform the cleaning process, thereby eliminating the problem of reduced processing apparatus operating rate. However, this method does not adequately remove foreign matter adhering to the transport device.

[0004] Also, a method has been proposed (see Patent Document 2) in which a substrate having an adhesive substance adhered thereto is used as a cleaning member to transport the substrate into a substrate processing apparatus, thereby removing foreign matter adhering to the transport device. This method is superior to the method described in Patent Document 1 in terms of foreign matter removal performance. However, the method described in Patent Document 2 can have a problem in that the adhesive substance adheres too strongly to the transport device at the contact point, making it difficult to separate. As a result, problems may arise in that the substrate having the adhesive substance adhered thereto cannot be reliably transported, that the transport device may be damaged, or that the transport device may be contaminated. On the other hand, if the adhesive force between the adhesive substance and the transport device becomes too weak, the cleaning member's ability to remove foreign matter may decrease, resulting in a problem in which sufficient cleaning effect cannot be obtained. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 11-87458 [Patent Document 2] Japanese Patent Application Publication No. 10-154686 [Patent Document 3] Japanese Patent Application Laid-Open No. 2007-307521 [Patent Document 4] Japanese Patent Application Laid-Open No. 2010-259970 Summary of the Invention [Problem to be solved by the invention]

[0006] An object of the present invention is to provide a cleaning sheet that is excellent in foreign matter removal performance and transport performance. [Means for solving the problem]

[0007] 1. A cleaning sheet according to an embodiment of the present invention includes a cleaning layer, the cleaning layer containing a polyimide-based resin including a structural unit having an alicyclic skeleton, and the polyimide-based resin contains a structural unit derived from a tetracarboxylic dianhydride having an alicyclic skeleton. 2. In the cleaning sheet described in 1 above, the content of the structural unit having an alicyclic skeleton may be 5 to 50 parts by weight relative to 100 parts by weight of the polyimide resin. 3. In the cleaning sheet according to 1 or 2 above, the polyimide resin may further contain a structural unit derived from a diamine having an alicyclic skeleton. 4. In the cleaning sheet according to any one of 1 to 3 above, the content of the structural unit derived from the tetracarboxylic dianhydride having an alicyclic skeleton may be 5 to 40 parts by weight relative to 100 parts by weight of the polyimide resin. 5. In the cleaning sheet according to any one of 1 to 4 above, the alicyclic skeleton of the tetracarboxylic acid dianhydride having an alicyclic skeleton may have 4 to 16 carbon atoms. 6. In the cleaning sheet according to any one of the above items 1 to 5, the polyimide resin may have a glass transition temperature (Tg) of 250°C to 300°C. 7. In the cleaning sheet according to any one of the above items 1 to 6, the cleaning layer may have a storage modulus at 25° C. of 100 MPa to 1000 MPa. 8. The cleaning sheet according to any one of 1 to 7 above may further comprise a support disposed adjacent to the cleaning layer. 9. A transport member with cleaning function of the present invention comprises the cleaning sheet according to any one of 1 to 8 above and a transport member. [Effects of the Invention]

[0008] According to the present invention, a cleaning sheet having excellent foreign matter removal performance and transport performance can be provided. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a schematic cross-sectional view of a cleaning sheet according to an embodiment of the present invention. [Figure 2] 1 is a schematic cross-sectional view of a cleaning sheet according to an embodiment of the present invention. [Figure 3] 1 is a schematic cross-sectional view of a cleaning sheet according to an embodiment of the present invention. [Figure 4] 1 is a schematic cross-sectional view of a cleaning function-equipped conveying member according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0010] A. Cleaning sheet A-1. Overview The cleaning sheet according to the embodiment of the present invention includes a cleaning layer. The cleaning sheet according to the embodiment of the present invention may be composed of only the cleaning layer, or may include other layers.

[0011] Fig. 1 is a schematic cross-sectional view showing one embodiment of a cleaning sheet according to an embodiment of the present invention. In Fig. 1, a cleaning sheet 100 has a cleaning layer 10 and a protective film 20 disposed on at least one surface of the cleaning layer 10. The protective film 20 may be provided for purposes such as protecting the cleaning layer 10, and may be omitted depending on the purpose. In other words, the cleaning sheet of the present invention may be composed of only the cleaning layer 10.

[0012] Fig. 2 is a schematic cross-sectional view showing another embodiment of a cleaning sheet according to an embodiment of the present invention. In Fig. 2, a cleaning sheet 100 has, in this order, a protective film 20, a cleaning layer 10, and an adhesive layer 30. The protective film 20 can be provided for the purpose of protecting the cleaning layer 10, and may be omitted depending on the purpose.

[0013] The cleaning sheet according to an embodiment of the present invention may further include a support disposed adjacent to the cleaning layer. In one embodiment, the support is disposed so as to be in contact with the cleaning layer. The support may be a transport support such as a dummy wafer. FIG. 3 is a schematic cross-sectional view showing another embodiment of the cleaning sheet according to an embodiment of the present invention. In FIG. 3, the cleaning sheet 100 has, in this order, a protective film 20, a cleaning layer 10, a support 40, and an adhesive layer 30. The protective film 20 may be provided for the purpose of protecting the cleaning layer 10, and may be omitted depending on the purpose. The adhesive layer 30 may also be omitted.

[0014] A-2. Cleaning layer The cleaning layer contains a polyimide resin. The content of the polyimide resin in the cleaning layer is preferably 50 to 100 parts by weight, more preferably 70 to 100 parts by weight, even more preferably 90 to 100 parts by weight, particularly preferably 95 to 100 parts by weight, and most preferably 98 to 100 parts by weight, relative to 100 parts by weight of the cleaning layer. The polyimide resin preferably has a soft segment. The soft segment is a segment that can impart flexibility to a polymer, and may be, for example, a segment having a long-chain linear group or a long-chain branched group in the main chain, and is soft and stretchable.

[0015] The polyimide resin contains a structural unit having an alicyclic skeleton. A cleaning layer formed using a polyimide resin containing a structural unit having an alicyclic skeleton exhibits favorable elasticity and excellent foreign matter removal and transport performance at temperatures (e.g., 0°C to 200°C) in the environment in which the cleaning sheet is used. Furthermore, the generation of foreign matter from the cleaning layer is minimal, preventing contamination of the object to be cleaned. Furthermore, heating during polyimide resin formation, for example, heating for imidization (e.g., heating at 250°C to 300°C), can impart flexibility, resulting in a cleaning sheet with excellent adhesion to the cleaning layer and adjacent layers. In particular, in the case of a polyimide resin containing a structural unit derived from a tetracarboxylic dianhydride having an alicyclic skeleton, although the mechanism is not clear, the surface free energy between the cleaning layer and the adjacent layer increases, resulting in a cleaning sheet with excellent adhesion between them. For example, a cleaning sheet with excellent adhesion between the support and the cleaning layer can be obtained. Such a cleaning sheet is particularly advantageous in that the cleaning layer is prevented from detaching during use, transport, etc. It is also advantageous in that peeling at the edge of the cleaning layer can be suppressed.

[0016] The content of the structural unit having an alicyclic skeleton in the polyimide resin is preferably 3 to 50 parts by weight, more preferably 5 to 50 parts by weight, even more preferably 8 to 50 parts by weight, and even more preferably 10 to 45 parts by weight, relative to 100 parts by weight of the polyimide resin. If the content is within this range, the above-mentioned effects become significant.

[0017] Among the monomer components for forming the polyamic acid, the content of the monomer having an alicyclic skeleton is preferably 3 to 50 parts by weight, more preferably 5 to 50 parts by weight, even more preferably 8 to 50 parts by weight, and still more preferably 10 to 45 parts by weight, relative to 100 parts by weight of the monomer components.

[0018] Typically, polyimide resins are obtained by imidizing polyamic acids, which can be obtained by reacting a tetracarboxylic dianhydride component and a diamine component as monomer components in a substantially equimolar ratio in any suitable organic solvent.

[0019] The tetracarboxylic dianhydride component contains a tetracarboxylic dianhydride having an alicyclic skeleton (hereinafter also simply referred to as an alicyclic tetracarboxylic dianhydride). That is, the polyimide resin contains structural units derived from an alicyclic tetracarboxylic dianhydride. The polyimide resin containing the structural units having an alicyclic skeleton can be obtained by using an alicyclic tetracarboxylic dianhydride. Alternatively, a polyimide resin containing structural units having an alicyclic skeleton may be obtained by using an alicyclic tetracarboxylic dianhydride in combination with a diamine compound having an alicyclic skeleton.

[0020] The number of carbon atoms in the alicyclic skeleton of the alicyclic tetracarboxylic dianhydride component is, for example, 4 to 16, and preferably 4 to 10. If the carbon number is within this range, the above-mentioned effect becomes remarkable.

[0021] Examples of alicyclic tetracarboxylic dianhydrides include 1,2,3,4-cyclobutane tetracarboxylic dianhydride, substituted cyclobutane tetracarboxylic dianhydride, 2,3,5-tricarboxycyclopentylacetic dianhydride, 5-(2,5-dioxotetrahydrofuran-3-yl)-3a,4,5,9b-tetrahydronaphtho[1,2-c]furan-1,3-dione, 5-(2,5-dioxotetrahydrofuran-3-yl)-8-methyl-3a,4,5,9b-tetrahydronaphtho[1,2-c]furan-1,3-dione, 2,4,6,8-tetracarboxybicyclo[3.3.0]octane-2:4,6:8-dianhydride, cyclopentane tetracarboxylic dianhydride, cyclohexane tetracarboxylic dianhydride, and 3,5,6-tricarboxy-2-carboxymethylnorbornane-2:3,5:6-dianhydride.

[0022] The content of the structural unit derived from the alicyclic tetracarboxylic dianhydride in the polyimide resin is, for example, 40 parts by weight or less, preferably 3 to 40 parts by weight, more preferably 5 to 40 parts by weight, and even more preferably 10 to 38 parts by weight, per 100 parts by weight of the polyimide resin. Using the alicyclic tetracarboxylic dianhydride in such a content ratio can prevent defects such as cracking and allow a preferable cleaning layer to be formed. Furthermore, if the content of the structural unit derived from the alicyclic tetracarboxylic dianhydride is 5 parts by weight or more per 100 parts by weight of the polyimide resin, the effect of using the alicyclic tetracarboxylic dianhydride becomes significant.

[0023] The content of the alicyclic tetracarboxylic dianhydride in the monomer components for forming the polyamic acid is, for example, 40 parts by weight or less, preferably 3 to 40 parts by weight, more preferably 5 to 40 parts by weight, and even more preferably 10 to 38 parts by weight, relative to 100 parts by weight of the monomer components.

[0024] The content of the alicyclic tetracarboxylic dianhydride in the tetracarboxylic dianhydride component for forming the polyamic acid can be, for example, 5 to 100 parts by weight relative to 100 parts by weight of the alicyclic tetracarboxylic dianhydride component, and the content may be 8 to 80 parts by weight, 10 to 60 parts by weight, or 10 to 50 parts by weight.

[0025] The tetracarboxylic dianhydride component may contain a tetracarboxylic dianhydride other than an alicyclic tetracarboxylic dianhydride. That is, in one embodiment, the polyimide resin is a resin obtained by using a tetracarboxylic dianhydride component and a diamine component as monomer components and imidizing a polyamic acid that is a reaction product of the monomer components, and the tetracarboxylic dianhydride component contains an alicyclic tetracarboxylic dianhydride and a tetracarboxylic dianhydride other than an alicyclic tetracarboxylic dianhydride.

[0026] The content of the tetracarboxylic dianhydride other than the alicyclic tetracarboxylic dianhydride in the tetracarboxylic dianhydride component for forming the polyamic acid can be, for example, 0 to 95 parts by weight relative to 100 parts by weight of the tetracarboxylic dianhydride component, and the content may be 20 to 92 parts by weight, or 40 to 90 parts by weight.

[0027] Examples of the tetracarboxylic dianhydride include 3,3',4,4'-biphenyltetracarboxylic dianhydride, 2,2',3,3'-biphenyltetracarboxylic dianhydride, 3,3',4,4'-benzophenonetetracarboxylic dianhydride, 2,2',3,3'-benzophenonetetracarboxylic dianhydride, 4,4'-oxydiphthalic dianhydride, 2,2-bis(2,3-dicarboxyphenyl)hexafluoropropane dianhydride, 2,2-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride (6FDA), bis(2,3-dicarboxyphenyl)methane dianhydride, bis(3,4-dicarboxyphenyl)methane dianhydride, bis(2,3-dicarboxyphenyl)sulfone dianhydride, bis(3,4-dicarboxyphenyl)sulfone dianhydride, pyromellitic dianhydride, and ethylene glycol bistrimellitic dianhydride. These may be used alone or in combination of two or more.

[0028] In one embodiment, the diamine component includes a diamine having an alicyclic skeleton (hereinafter also simply referred to as an alicyclic diamine). That is, the polyimide resin may include a structural unit derived from a diamine having an alicyclic skeleton.

[0029] The number of carbon atoms in the alicyclic skeleton of the alicyclic diamine is, for example, 4 to 16, and preferably 4 to 10. If the carbon number is within this range, the above-mentioned effect becomes significant.

[0030] Examples of the alicyclic diamine include 1,4-cyclohexanediamine, 1,3-cyclohexanediamine, 1,4-bis(aminomethyl)cyclohexane, 1,3-bis(aminomethyl)cyclohexane, 4,4'-methylenebis(cyclohexylamine), 4,4'-methylenebis(2-methylcyclohexylamine), isophoronediamine, 1,3-diaminoadamantane, norbornanediamine, etc. These may be used alone or in combination of two or more.

[0031] In one embodiment, the alicyclic diamine has a norbornane skeleton. The use of an alicyclic diamine having a norbornane skeleton makes the above-mentioned effect more pronounced. Examples of alicyclic diamines having a norbornane skeleton include norbornane diamines. Examples of norbornane diamines include 2,5-norbornane dimethylamine and 2,6-norbornane dimethylamine.

[0032] The content of the alicyclic diamine-derived structural unit in the polyimide resin is, for example, 20 parts by weight or less, preferably 5 to 20 parts by weight, more preferably 5 to less than 19 parts by weight, even more preferably 6 to 17 parts by weight, and particularly preferably 7 to 15 parts by weight, per 100 parts by weight of the polyimide resin. Using the alicyclic diamine in such a content ratio can prevent defects such as cracking and allow a preferable cleaning layer to be formed. Furthermore, if the content of the alicyclic diamine-derived structural unit is 5 parts by weight or more per 100 parts by weight of the polyimide resin, the effect of using the alicyclic diamine becomes significant.

[0033] The content of the alicyclic diamine in the monomer components for forming the polyamic acid is, for example, 20 parts by weight or less, preferably 5 to 20 parts by weight, more preferably 5 to less than 19 parts by weight, even more preferably 6 to 17 parts by weight, and particularly preferably 7 to 15 parts by weight, relative to 100 parts by weight of the monomer components.

[0034] The content of the alicyclic diamine in the diamine component for forming the polyamic acid can be, for example, 5 to 50 parts by weight per 100 parts by weight of the diamine component, or 10 to 40 parts by weight, or 10 to 30 parts by weight.

[0035] The diamine component may contain a diamine compound other than an alicyclic diamine. By using a diamine other than an alicyclic diamine, gelation can be prevented, a varnish as a cleaning layer-forming composition can be preferably prepared, and a varnish that is excellent in processability when formed into a sheet can be obtained.

[0036] In the diamine component for forming the polyamic acid, the content of the diamine compound other than the alicyclic diamine can be, for example, 50 to 95 parts by weight relative to 100 parts by weight of the diamine component, or 60 to 90 parts by weight, or 70 to 90 parts by weight.

[0037] Examples of diamine compounds other than alicyclic diamines include diamine compounds having at least two terminals with amine structures and a polyether structure (hereinafter also referred to as PE diamine compounds), aliphatic diamines, and aromatic diamines. Among these, PE diamine compounds are preferably used. Dimer diamine may also be used as the diamine compound.

[0038] Any appropriate compound can be used as the PE diamine compound. Examples of PE diamine compounds include terminal diamines having a polypropylene glycol structure, terminal diamines having a polyethylene glycol structure, terminal diamines having a polytetramethylene glycol structure, and terminal diamines having a combination of these structures. More specifically, examples of PE diamine compounds include PE diamine compounds having at least two terminal amine structures prepared from ethylene oxide, propylene oxide, polytetramethylene glycol, polyamine, or a mixture thereof. The structural units derived from PE diamine compounds can form soft segments in polyimide resins.

[0039] The content of PE diamine in the monomer components for forming the polyamic acid is preferably 10 to 60 parts by weight, more preferably 12 to 50 parts by weight, even more preferably 15 to 45 parts by weight, and particularly preferably 20 to 40 parts by weight, per 100 parts by weight of the monomer components. Within this range, a cleaning sheet with particularly excellent foreign matter removal performance can be obtained. Furthermore, a cleaning layer-forming composition that can be easily turned into a varnish can be obtained.

[0040] The content of PE diamine in the diamine component for forming the polyamic acid is preferably 20 to 80 parts by weight, more preferably 25 to 75 parts by weight, and even more preferably 30 to 70 parts by weight, per 100 parts by weight of the diamine component. Within this range, a cleaning sheet with particularly excellent foreign matter removal performance can be obtained. Furthermore, a cleaning layer-forming composition that can be easily turned into a varnish can be obtained.

[0041] Examples of the aliphatic diamine include ethylenediamine, hexamethylenediamine, 1,8-, 1,10-diaminodecane, 1,12-diaminododecane, 4,9-dioxa-1,12-diaminododecane, and 1,3-bis(3-aminopropyl)-1,1,3,3-tetramethyldisiloxane (α,ω-bisaminopropyltetramethyldisiloxane). The molecular weight of the aliphatic diamine is preferably 50 to 1,000,000, and more preferably 100 to 30,000.

[0042] Examples of aromatic diamines include 2,2-bis[4-(4-aminophenoxy)phenyl]propane, 4,4'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 3,3'-diaminodiphenyl ether, m-phenylenediamine, p-phenylenediamine, 4,4'-diaminodiphenylpropane, 3,3'-diaminodiphenylmethane, 4,4'-diaminodiphenyl sulfide, 3,3'-diaminodiphenyl sulfide, 4,4'-diaminodiphenyl sulfone, 3,3'-diaminodiphenyl sulfone, 1,4-bis(4-aminophenoxy)benzene, 1,3-bis(4-aminophenoxy)benzene, 1,3-bis(3-aminophenoxy)benzene, 1,3-bis(4-aminophenoxy)-2,2-dimethylpropane, and 4,4'-diaminobenzophenone.

[0043] Examples of organic solvents (reaction solvents) used in the reaction between the tetracarboxylic dianhydride component and the diamine component include N,N-dimethylacetamide, N-methyl-2-pyrrolidone, and N,N-dimethylformamide. A non-polar solvent (e.g., toluene or xylene) may be used in combination to adjust the solubility of the raw materials.

[0044] The reaction temperature between the tetracarboxylic dianhydride and the diamine is preferably 20°C or higher, and more preferably 20°C to 100°C.

[0045] The imidization of polyamic acid is typically carried out by heat treatment in an inert atmosphere (typically, a vacuum or nitrogen atmosphere). The heat treatment temperature is preferably 150°C or higher, and more preferably 180°C to 450°C.

[0046] The glass transition temperature (Tg) of the polyimide resin is preferably 200°C to 300°C, more preferably 250°C to 300°C, and even more preferably 250°C to 285°C. Within such a range, the effects of the present invention become significant. The glass transition temperature (Tg) is measured using a thermomechanical analyzer (TMA). The measurement method will be described in detail below.

[0047] The cleaning layer may contain any other appropriate components within the scope of not impairing the effects of the present invention, such as heat-resistant resins, surfactants, plasticizers, antioxidants, conductivity-imparting agents, ultraviolet absorbers, and light stabilizers.

[0048] The thickness of the cleaning layer is preferably 1 μm to 100 μm, more preferably 1 μm to 50 μm, still more preferably 1 μm to 30 μm, and particularly preferably 1 μm to 20 μm.

[0049] In one embodiment, the cleaning layer has substantially no adhesive force. Specifically, the 180° peel adhesion strength A, as defined by JIS-Z-0237, against the mirror surface of a silicon wafer is preferably less than 0.20 N / 10 mm, and more preferably 0.01 to 0.10 N / 10 mm. When the 180° peel adhesion strength A, as defined by JIS-Z-0237, of the cleaning layer against the mirror surface of a silicon wafer is within this range, the cleaning layer has substantially no adhesive force, and the adhesiveness between the cleaning layer and, for example, a contact portion with a transport device in a substrate processing apparatus can be reduced. As a result, substrates can be transported reliably and the transport device can be less likely to be damaged.

[0050] The cleaning layer preferably has a 180-degree peel adhesion B from the mirror surface of a dummy wafer of 2 N / 10 mm or more, more preferably 3 N / 10 mm or more, even more preferably 3.5 N / 10 mm or more, particularly preferably 5 N / 10 mm or more, and most preferably 7 N / 10 mm or more. If the 180-degree peel adhesion B is within the above range, for example, the adhesion between the cleaning layer and a transport member such as a dummy wafer is increased, making it difficult for the cleaning layer to peel off from the transport member such as a dummy wafer during cleaning. The higher the 180-degree peel adhesion B from the mirror surface of a dummy wafer, the better, but the upper limit is, for example, 20 N / 10 mm (preferably 30 N / 10 mm, more preferably 50 N / 20 mm). The 180-degree peel adhesion B is measured, for example, by forming a cleaning layer on the mirror surface of a silicon wafer as a dummy wafer. The method for measuring the 180-degree peel adhesion B will be described later.

[0051] The storage modulus of the cleaning layer at 25°C may be 100 MPa to 2500 MPa, 100 MPa to 2000 MPa, 100 MPa to 1500 MPa, or 100 MPa to 1000 MPa. It is preferably 100 MPa to 1000 MPa. Within the above range, a cleaning sheet with significantly excellent foreign matter removal performance can be obtained. The method for measuring the storage modulus will be described later.

[0052] The storage modulus of the cleaning layer at 150°C may be 80 MPa to 2000 MPa, or 100 MPa to 1000 MPa. It is preferably 100 MPa to 1000 MPa. Within the above range, a cleaning sheet with excellent foreign matter removal performance can be obtained. In the present invention, this is preferred because it can maintain a storage modulus that allows the cleaning layer to exhibit favorable foreign matter removal performance even in a high-temperature environment.

[0053] The storage modulus of the cleaning layer at 300° C. may be 0.1 MPa to 500 MPa, 0.2 MPa to 250 MPa, 0.5 MPa to 150 MPa, or 1 MPa to 100 MPa. Within these ranges, a cleaning sheet having excellent adhesion between the support and the cleaning layer can be obtained.

[0054] The number of cleaning layers remaining on the mirror surface of a dummy wafer as measured by the cross-cut method is preferably 15 / 25 or more, more preferably 18 / 25 or more, even more preferably 20 / 25 or more, particularly preferably 23 / 25 or more, and most preferably 25 / 25 or more. If the number of cleaning layers remaining on the mirror surface of a dummy wafer as measured by the cross-cut method is within the above range, for example, adhesion between the cleaning layer and a transport member such as a dummy wafer is increased, and the cleaning layer is less likely to peel off from a transport member such as a dummy wafer during cleaning.

[0055] The number of cleaning layers remaining on the mirror surface of a dummy wafer using the cross-cut cleaning layer method can be measured, for example, by using a cutter knife to make six parallel cuts in the substrate at 2 mm intervals on the test surface, and then making six more parallel cuts at 2 mm intervals perpendicular to the cuts, thereby creating 25 grids, firmly pressing a tape having an adhesive strength of 16 N / 20 mm (for example, "BT-315ST" manufactured by Nitto Denko Corporation) onto the grid areas, quickly peeling off the end of the tape at a 45° angle, and evaluating the state of the grids by comparing them with a standard diagram.

[0056] A-3.Support The cleaning sheet may have a support, which may be a single layer or a multi-layer body.

[0057] The thickness of the support may be any appropriate thickness as long as it does not impair the effects of the present invention, and is preferably 500 μm or less, more preferably 1 μm to 400 μm, even more preferably 1 μm to 300 μm, particularly preferably 1 μm to 200 μm, and most preferably 1 μm to 100 μm.

[0058] Any suitable material can be used as the material for the support, as long as it does not impair the effects of the present invention. Examples of the support include films of plastics, engineering plastics, and super-engineering plastics. Specific examples of plastics, engineering plastics, and super-engineering plastics include polyimide, polyethylene, polyethylene terephthalate, acetyl cellulose, polycarbonate, polypropylene, and polyamide.

[0059] The physical properties of the support material, such as the molecular weight, can be appropriately selected depending on the purpose.

[0060] The method for forming the support can be appropriately selected depending on the purpose.

[0061] The surface of the support may be subjected to a conventional surface treatment, such as a chemical or physical treatment such as chromate treatment, ozone exposure, flame exposure, high-voltage shock exposure or ionizing radiation treatment, or a coating treatment with a primer, in order to improve adhesion and retention of adjacent layers.

[0062] The peel strength of the cleaning layer from the support at 23°C is, for example, 3 N / 10 mm or more, preferably 3.5 N / 10 mm or more, and more preferably 5 N / 10 mm or more. The higher the peel strength of the cleaning layer from the support at 23°C, the better, but the upper limit is, for example, 50 N / 10 mm. The peel strength is measured in accordance with the method for measuring "180-degree peel adhesive strength B."

[0063] A-4.Adhesive layer The cleaning sheet may include a pressure-sensitive adhesive layer. Any suitable material may be used for the pressure-sensitive adhesive layer as long as it does not impair the effects of the present invention. Examples of materials for the pressure-sensitive adhesive layer include acrylic pressure-sensitive adhesives, silicone pressure-sensitive adhesives, rubber pressure-sensitive adhesives, and urethane pressure-sensitive adhesives.

[0064] The adhesive layer is provided for attaching the cleaning sheet to the mirror surface of a dummy wafer, for example, so that the cleaning sheet is attached to the dummy wafer as a transport member, thereby forming a transport member with cleaning function according to an embodiment of the present invention.

[0065] The adhesive layer has a 180-degree peel adhesion C, as specified in JIS-Z-0237, to the mirror surface of a dummy wafer of preferably 10 N / 10 mm or more, more preferably 15 N / 10 mm or more, even more preferably 20 N / 10 mm or more, particularly preferably 25 N / 10 mm or more, and most preferably 30 N / 10 mm or more. If the 180-degree peel adhesion C, as specified in JIS-Z-0237, of the adhesive layer to the mirror surface of a dummy wafer is within the above range, for example, the adhesive strength between the adhesive layer and the dummy wafer is increased, making it difficult for the cleaning sheet to peel off from the dummy wafer during cleaning.

[0066] The thickness of the pressure-sensitive adhesive layer is preferably 1 μm to 200 μm, more preferably 2 μm to 100 μm, even more preferably 3 μm to 80 μm, particularly preferably 4 μm to 60 μm, and most preferably 5 μm to 50 μm.

[0067] A-5. Protective film The cleaning sheet of the present invention may have a protective film to protect the cleaning layer, the support, the adhesive layer, etc. The protective film can be peeled off at an appropriate stage.

[0068] Any appropriate material can be used as the material for the protective film as long as it does not impair the effects of the present invention. Examples of materials for the protective film include polyolefins such as polyethylene, polypropylene, polybutene, polybutadiene, and polymethylpentene, polyvinyl chloride, vinyl chloride copolymers, polyethylene terephthalate, polybutylene terephthalate, polyurethane, ethylene-vinyl acetate copolymers, ionomer resins, ethylene-(meth)acrylic acid copolymers, ethylene-(meth)acrylic acid ester copolymers, polystyrene, polycarbonate, polyimide, and fluororesins.

[0069] The protective film may be subjected to any appropriate release treatment as long as the effects of the present invention are not impaired. The release treatment is typically performed using a release agent. Examples of the release agent include silicone-based release agents, long-chain alkyl-based release agents, fluorine-based release agents, fatty acid amide-based release agents, and silica-based release agents.

[0070] The thickness of the protective film is preferably 1 μm to 100 μm.

[0071] The method for forming the protective film is appropriately selected depending on the purpose, and the film can be formed by, for example, injection molding, extrusion molding, blow molding, or the like.

[0072] B. Cleaning Sheet Manufacturing Method Any suitable method can be used to produce the cleaning sheet according to an embodiment of the present invention, as long as it does not impair the effects of the present invention. Examples of such methods include (1) a method in which a cleaning layer-forming composition (varnish) containing the polyamic acid is cast onto a support, a uniform film is formed using a spin coater, or the like, and then heated to form a cleaning layer directly on the support. A preferred method is to produce the cleaning sheet according to an embodiment of the present invention by applying the cleaning layer-forming composition (varnish) to the support using a spin coater to form a film, leaving it to stand as needed, and heating and / or drying it as needed to form a cleaning layer on the support.

[0073] The viscosity of the cleaning layer-forming composition (varnish) is preferably 100 mPa·s to 4000 mPa·s, more preferably 300 mPa·s to 3000 mPa·s, and even more preferably 500 mPa·s to 2000 mPa·s.

[0074] The rotation speed when applying the cleaning layer-forming composition (varnish) by a spin coater to form a film is preferably 400 rpm or more, more preferably 600 rpm or more, and even more preferably 800 rpm or more. The upper limit of the rotation speed is preferably 3000 rpm or less, in order to further exhibit the effects of the present invention.

[0075] The rotation time when the cleaning layer-forming composition (varnish) is applied by a spin coater to form a film is preferably 5 to 200 seconds, more preferably 10 to 150 seconds, and even more preferably 20 to 60 seconds.

[0076] In the method for producing a cleaning sheet according to an embodiment of the present invention, the varnish can be made smoother by coating the cleaning layer-forming composition (varnish) on a support to form a film and then leaving it to stand for a period of preferably 5 to 1000 seconds, more preferably 30 to 600 seconds, and even more preferably 100 to 400 seconds.

[0077] In the method for producing a cleaning sheet according to an embodiment of the present invention, the cleaning layer-forming composition (varnish) may be applied to form a film, and then heated and / or dried. The heating or drying temperature is preferably 50° C. to 200° C., and more preferably 80° C. to 150° C. The heating or drying time is preferably 100 to 900 seconds, more preferably 300 to 900 seconds, and even more preferably 600 to 900 seconds.

[0078] In the method for producing a cleaning sheet according to an embodiment of the present invention, the cleaning layer-forming composition (varnish) may be applied to form a film, heated, dried, and then cured in a vacuum or nitrogen atmosphere. The curing temperature is preferably 200°C to 400°C, and more preferably 250°C to 350°C. The heating or drying time is preferably 30 minutes to 300 minutes, and more preferably 60 to 200 minutes. In this curing step, the cleaning resin is softened by being heated to a temperature above its glass transition temperature, improving its conformability to the wafer surface and improving adhesion between the wafer and the cleaning layer.

[0079] C. Cleaning function transport component A transport member with cleaning function according to an embodiment of the present invention includes the cleaning sheet and a transport member.

[0080] Fig. 4 is a schematic cross-sectional view showing one embodiment of a cleaning-function-equipped transport member of the present invention. In Fig. 4, a cleaning-function-equipped transport member 300 has a cleaning sheet 100 and a transport member 200. When the cleaning sheet 100 has an adhesive layer, the adhesive layer is preferably the outermost layer of the cleaning sheet 100 on the transport member 200 side.

[0081] Any suitable conveying member can be used as the conveying member as long as it does not impair the effects of the present invention. Examples of such conveying members include semiconductor wafers (e.g., silicon wafers), substrates for flat panel displays such as LCDs and PDPs, compact discs, and MR heads. Among these conveying members, when the purpose is to clean a wafer conveying device in a substrate processing apparatus, a semiconductor wafer (e.g., silicon wafer) is typically used. [Example]

[0082] The present invention will be described in more detail below with reference to examples and comparative examples. However, the present invention is not limited to these examples. In the following description, "parts" and "%" are by weight unless otherwise specified.

[0083] <Evaluation method> (1) Storage modulus The storage modulus of the cleaning layer was measured using a solid viscoelasticity measuring device (Model RSAG-2, manufactured by TA Instruments Japan, Inc.). Specifically, a test piece 30 mm long (measurement length) and 10 mm wide was cut out, and the storage modulus of the test piece was measured using a solid viscoelasticity measuring device (Model RSAG-2, manufactured by TA Instruments Japan, Inc.) at a frequency of 1 Hz, a heating rate of 10°C / min, and a chuck distance of 10 mm over the temperature range of 0°C to 200°C. The storage moduli at 25°C, 150°C, and 300°C are shown in Table 1. (2) Adhesion test The adhesive strength of the cleaning layer to the mirror surface of the dummy wafer was evaluated by the cross-cut method. Using a cutter knife, six parallel cuts were made in the adhesive layer at 2 mm intervals on the substrate, and six more parallel cuts were made at 2 mm intervals perpendicular to the first cuts, creating 25 grids. Tape with an adhesive strength of 16 N / 20 mm (BT-315ST, manufactured by Nitto Denko Corporation) was then pressed onto the grid areas, and the edge of the tape was peeled off at a 45° angle, and the remaining grids were measured. (3) Peeling force (180-degree peeling adhesive force B from the mirror surface of a dummy wafer) The peeling force (180-degree peeling adhesive force B of the cleaning layer against the mirror surface of the dummy wafer) was measured using a tensile tester (product name "Autograph AGS-J", manufactured by Shimadzu Corporation) on a sample piece 10 mm wide x 100 mm long at an ambient temperature of 23°C, a peeling angle of 180°, and a pulling speed of 10 mm / min. The sample pieces were prepared in the following manner. A backing tape (product name "BT-315" manufactured by Nitto Denko Corporation) was attached to the cleaning layer of the cleaning-function-equipped transport member (cleaning layer / dummy wafer (silicon wafer)) obtained in the Examples or Comparative Examples by pressing the tape back and forth once with a 2 kg roller. The tape and cleaning layer were then cut parallel to the thickness of the laminate so that the area where the tape was attached (the area where the peel force was to be tested) was 10 mm wide and at least 100 mm long. In this way, a cleaning layer sample (10 mm wide x 100 mm long) with the backing tape was prepared. The peel force of this sample was measured when peeling the cleaning layer from the silicon wafer at an ambient temperature of 23°C, a peel angle of 180°, and a pulling speed of 10 mm / min. (4) Glass transition temperature (Tg) of polyimide resin The glass transition temperature (Tg) of the polyimide resin can be measured using a thermomechanical analyzer (TMA). An example of a TMA is the "TMA7100" manufactured by Hitachi High-Tech Science Corporation. The cleaning layer was cut into a 5 mm wide x 30 mm long piece, and the measurement was performed in tensile mode with a load of 50 mN, a heating rate of 5°C / min, a nitrogen gas atmosphere, and a temperature range of 25°C to 400°C. The Tg was determined from the intersection of the extended straight lines on the high-temperature and low-temperature sides of the TMA curve. (5) Cleaning ability The mirror surface of a 6-inch silicon wafer was left in the atmosphere for 6 hours to produce a contaminated 6-inch silicon wafer, and the number of foreign particles on the mirror surface was measured (Count 1). Next, the mirror surface of the contaminated 6-inch silicon wafer was attached to a cleaning sheet, which was then peeled off, and the number of foreign particles on the mirror surface of the silicon wafer after peeling was measured (Count 2). The dust removal ability was calculated using the following formula. Dust removal performance (%)=[(Count1-Count2) / Count1]×100 Based on the dust removal performance, the cleaning performance was evaluated according to the following criteria. ◎ (Excellent): Dust removal rate of 70% or more Good: Dust removal rate is 50% or more but less than 70% △ (Acceptable): Dust removal rate is 20% or more but less than 50% × (Not acceptable): The cleaning layer adheres to the mirror surface / dust removal efficiency is less than 20%

[0084] Example 1 The amine components were 2.8 parts by weight of diamine monomer (4,4'-DPE, 4,4'-diaminodiphenyl ether in the table) and polyetheramine (D-2000, H2N-CH(CH3)-(O-CH2-CH(CH3)) nThree parts by weight of -NH2 (trade name "Jeffamine D-2000" manufactured by HUNTSMAN, molecular weight 2000, n = approximately 33) was dissolved in 50 parts by weight of dimethylacetamide. Next, 3.2 parts by weight of alicyclic tetracarboxylic dianhydride ("CBDA" in the table, 1,2,3,4-cyclobutanetetracarboxylic dianhydride) was added and reacted to obtain Varnish A. This varnish A was applied to the entire mirror surface of a 12-inch silicon wafer by spin coating (1000 rpm x 30 seconds). Next, the wafer was dried on a hot plate at 110°C for 10 minutes, and then cured in a vacuum drying furnace at 300°C for 180 minutes, to obtain a cleaning function-equipped conveying member A (cleaning layer / dummy wafer (silicon wafer)) in which a cleaning layer was formed to cover the entire surface of one side of the silicon wafer. The obtained transport member with cleaning function was subjected to the above evaluations, and the results are shown in Table 1.

[0085] [Examples 2 to 9, Comparative Example 1, Reference Example 1] A cleaning-function-equipped transport member was obtained in the same manner as in Example 1, except that the blending amounts of each component were as shown in Table 1. The obtained cleaning-function-equipped transport member was subjected to the above-mentioned evaluations. The results are shown in Table 1. Note that the alicyclic diamine (NBDA) in the table is norbornane diamine as the diamine component, and the dicarboxylic acid anhydride (PMDA) in the table is pyromellitic dianhydride as the tetracarboxylic acid dianhydride component. Furthermore, in Reference Example 1, a cleaning layer could not be formed.

[0086] [Table 1]

[0087] As is clear from Table 1, the Examples have excellent foreign matter removal performance, and also excellent results in the adhesion strength test and the peel strength test (180-degree peel adhesion strength B of the cleaning layer from the mirror surface of a dummy wafer), i.e., cleaning sheets with excellent transport performance are obtained. On the other hand, the Comparative Examples have poor results in the adhesion strength test and the peel strength test. [Industrial Applicability]

[0088] The cleaning sheet and the transport member with cleaning function of the present invention are suitably used for cleaning substrate processing equipment such as various manufacturing equipment and inspection equipment. [Explanation of symbols]

[0089] Cleaning Sheets 100 Cleaning Layer 10 Protective film 20 Adhesive layer 30 Support 40 Cleaning function-equipped conveying member 300 Conveying member 200

Claims

1. A cleaning layer is provided, the cleaning layer contains a polyimide resin containing a structural unit having an alicyclic skeleton, The polyimide resin contains a structural unit derived from a tetracarboxylic dianhydride having an alicyclic skeleton. Cleaning sheet.

2. 2. The cleaning sheet according to claim 1, wherein the content of the structural unit having an alicyclic skeleton is 5 to 50 parts by weight based on 100 parts by weight of the polyimide resin.

3. The cleaning sheet according to claim 1 , wherein the polyimide resin further contains a structural unit derived from a diamine having an alicyclic skeleton.

4. 2. The cleaning sheet according to claim 1, wherein the content of the structural unit derived from the tetracarboxylic dianhydride having an alicyclic skeleton is 5 to 40 parts by weight relative to 100 parts by weight of the polyimide resin.

5. 2. The cleaning sheet according to claim 1, wherein the alicyclic skeleton of the tetracarboxylic acid dianhydride has 4 to 16 carbon atoms.

6. 2. The cleaning sheet according to claim 1, wherein the polyimide resin has a glass transition temperature (Tg) of 250°C to 300°C.

7. 2. The cleaning sheet according to claim 1, wherein the cleaning layer has a storage modulus at 25° C. of 100 MPa to 1000 MPa.

8. The cleaning sheet of claim 1 , further comprising a support positioned adjacent the cleaning layer.

9. A conveying member with a cleaning function, comprising the cleaning sheet according to claim 1 and a conveying member.

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