Cleaning sheet and conveying member with cleaning function

Abstract

The invention relates to a cleaning sheet and a conveying member with a cleaning function. Provided is a cleaning sheet which has excellent foreign matter removal performance and in which detachment of a cleaning layer is prevented. A cleaning sheet according to an embodiment of the present invention is provided with a cleaning layer containing a polyimide resin containing a structural unit derived from a diamine having an alicyclic skeleton.

Description

Technical Field

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

[0002] Various substrate processing equipment, such as those used in manufacturing and inspection equipment for semiconductors, flat panel displays, and printed circuit boards, where foreign matter is undesirable, uses a conveyor device (typically a chuck table) to physically contact the substrate while handling it. If foreign matter adheres to the conveyor device, it can contaminate subsequent substrates one by one, necessitating periodic system shutdowns and cleaning. This results in reduced processing equipment operating rates and a significant labor burden for cleaning the equipment.

[0003] To overcome this problem, a method has been proposed for removing foreign matter attached to the conveyor by conveying a plate-like member into a substrate processing apparatus (see Patent Document 1). This method eliminates the need to stop the substrate processing apparatus for cleaning, thus eliminating the problem of reduced processing apparatus operating efficiency. However, this method does not fully remove foreign matter attached to the conveyor.

[0004] In addition, a method for removing foreign matter attached to a conveying device by transporting a substrate fixed with an adhesive substance as a cleaning member into a substrate processing device has been proposed (see patent document 2). Compared with the method described in patent document 1, this method has excellent foreign matter removal performance. However, the method described in patent document 2 may cause the following problems: the adhesive substance and the contact portion of the conveying device are too strongly bonded and thus cannot be peeled off. As a result, the following problems may arise: the problem of being unable to reliably transport the substrate fixed with the adhesive substance, the problem of damaging the conveying device, and the problem of contaminating the conveying device. On the other hand, if the adhesion between the adhesive substance and the conveying device is too small, the foreign matter removal performance of the cleaning member will be reduced, and the problem of not being able to obtain a sufficient cleaning effect will arise.

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: Japanese Patent Application Laid-Open No. 11-87458

[0008] Patent Document 2: Japanese Patent Application Laid-Open No. 10-154686

[0009] Patent Document 3: Japanese Patent Application Laid-Open No. 2007-307521

[0010] Patent Document 4: Japanese Patent Application Laid-Open No. 2010-259970 Summary of the Invention

[0011] Problems to be solved by the invention

[0012] An object of the present invention is to provide a cleaning sheet having excellent foreign matter removal performance and conveying performance.

[0013] Solutions for solving problems

[0014] 1. A cleaning sheet according to an embodiment of the present invention includes a cleaning layer containing a polyimide-based resin containing a structural unit derived from a diamine having an alicyclic skeleton.

[0015] 2. In the cleaning sheet described in 1 above, the content ratio of the structural unit derived from the diamine having an alicyclic skeleton may be 5 to 20 parts by weight relative to 100 parts by weight of the polyimide resin.

[0016] 3. In the cleaning sheet described in 1 or 2 above, the alicyclic skeleton may have 4 to 16 carbon atoms.

[0017] 4. In the cleaning sheet according to any one of 1 to 3 above, the diamine having an alicyclic skeleton may have a norbornane skeleton.

[0018] 5. In the cleaning sheet according to any one of 1 to 4 above, the polyimide resin may have a glass transition temperature (Tg) of 250°C to 300°C.

[0019] 6. In the cleaning sheet according to any one of 1 to 3 above, the cleaning layer may have a storage modulus at 25° C. of 100 MPa to 1000 MPa.

[0020] 7. The cleaning sheet according to any one of 1 to 6 above may further include a support disposed adjacent to the cleaning layer.

[0021] 8. The transport member with a cleaning function of the present invention comprises the cleaning sheet according to any one of 1 to 7 above and a transport member.

[0022] Effects of the Invention

[0023] According to the present invention, a cleaning sheet having excellent foreign matter removal performance and conveying performance can be provided. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a schematic cross-sectional view of a cleaning sheet according to an embodiment of the present invention.

[0025] Figure 2 This is a schematic cross-sectional view of a cleaning sheet according to an embodiment of the present invention.

[0026] Figure 3 This is a schematic cross-sectional view of a cleaning sheet according to an embodiment of the present invention.

[0027] Figure 4 This is a schematic cross-sectional view of a conveying member with a cleaning function according to an embodiment of the present invention.

[0028] Description of Reference Numerals

[0029] Cleaning tablets 100

[0030] Cleaning layer 10

[0031] Protective film 20

[0032] Adhesive layer 30

[0033] Support body 40

[0034] Conveying member 300 with cleaning function

[0035] Conveying member 200 DETAILED DESCRIPTION

[0036] A. Cleaning tablets

[0037] A-1. Summary

[0038] 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.

[0039] Figure 1 Schematic cross-sectional view showing one embodiment of a cleaning sheet according to an embodiment of the present invention. Figure 1 In the embodiment, the cleaning sheet 100 includes a cleaning layer 10 and a protective film 20 disposed on at least one surface of the cleaning layer 10. The protective film 20 is provided for the purpose of protecting the cleaning layer 10 and may be omitted depending on the purpose. In other words, the cleaning sheet of the present invention may consist solely of the cleaning layer 10.

[0040] Figure 2 This is a schematic cross-sectional view showing another embodiment of a cleaning sheet according to an embodiment of the present invention. Figure 2 In the embodiment, the cleaning sheet 100 includes a protective film 20, a cleaning layer 10, and an adhesive layer 30 in this order. The protective film 20 is provided for the purpose of protecting the cleaning layer 10, and may be omitted depending on the purpose.

[0041] The cleaning sheet according to an embodiment of the present invention may further include a support body disposed adjacent to the cleaning layer. In one embodiment, the support body is disposed in contact with the cleaning layer. The support body may be a support body for transporting a dummy wafer or the like. Figure 3 This is a schematic cross-sectional view showing another embodiment of a cleaning sheet according to an embodiment of the present invention. Figure 3In the embodiment, the cleaning sheet 100 comprises a protective film 20, a cleaning layer 10, a support 40, and an adhesive layer 30 in this order. The protective film 20 is provided for the purpose of protecting the cleaning layer 10 and may be omitted depending on the purpose. In addition, the adhesive layer 30 may also be omitted.

[0042] A-2. Cleaning layer

[0043] The cleaning layer comprises 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, further 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. A soft segment is a segment that imparts flexibility to a polymer, for example, a segment having a long-chain linear group or a long-chain branched group in the main chain, which is soft and stretchable.

[0044] Typically, polyimide resins are obtained by imidizing polyamic acid, which can be obtained by using a tetracarboxylic dianhydride component and a diamine component as monomer components and reacting them in a substantially equimolar ratio in any appropriate organic solvent.

[0045] The diamine component includes a diamine having an alicyclic skeleton (hereinafter also referred to as alicyclic diamine). That is, the polyimide resin includes a structural unit derived from a diamine having an alicyclic skeleton. The cleaning layer obtained using the diamine having an alicyclic skeleton preferably has elasticity at the temperature of the environment in which the cleaning sheet is used (for example, 0°C to 200°C), and has excellent foreign matter removal performance and transportation performance. In addition, less foreign matter is generated from the cleaning layer, which can prevent contamination of the cleaning object. Furthermore, by heating during the generation of the polyimide resin, such as heating for imidization (for example, heating at 250°C to 300°C), it is preferably exhibited flexibility, thereby obtaining a cleaning sheet having excellent adhesion to the layer adjacent to the cleaning layer. For example, a cleaning sheet having excellent adhesion between the support and the cleaning layer can be obtained. Such a cleaning sheet is particularly advantageous in preventing the cleaning layer from detaching during use, transportation, etc. In addition, it is also advantageous in that peeling at the end of the cleaning layer can be suppressed.

[0046] The number of carbon atoms in the alicyclic skeleton of the alicyclic diamine is, for example, 4 to 16, or preferably 4 to 10. When the carbon atoms are within this range, the above-mentioned effect is remarkable.

[0047] 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, and norbornanediamine. These can be used alone or in combination of two or more.

[0048] In one embodiment, the alicyclic diamine has a norbornane skeleton. The above-mentioned effect is significant when an alicyclic diamine having a norbornane skeleton is used. Examples of alicyclic diamines having a norbornane skeleton include norbornane diamine. Examples of norbornane diamines include 2,5-norbornane dimethylamine and 2,6-norbornane dimethylamine.

[0049] In the polyimide resin, the content of the structural units derived from the alicyclic diamine is, for example, 20 parts by weight or less, preferably 5 to 20 parts by weight, more preferably 5 parts by weight or more and less than 19 parts by weight, further preferably 6 to 17 parts by weight, and particularly preferably 7 to 15 parts by weight, relative to 100 parts by weight of the polyimide resin. Using the alicyclic diamine at such a content prevents problems such as cracking, thereby preferably forming a cleaning layer. Furthermore, when the content of the structural units derived from the alicyclic diamine is 5 parts by weight or more relative to 100 parts by weight of the polyimide resin, the effects of using the alicyclic diamine are significant.

[0050] The content ratio of the alicyclic diamine in the monomer components for forming the above-mentioned polyamic acid is, for example, 20 parts by weight or less, preferably 5 to 20 parts by weight, more preferably 5 parts by weight or more and less than 19 parts by weight, further 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.

[0051] The content of the alicyclic diamine in the diamine component used to form the polyamic acid may be, for example, 5 to 50 parts by weight, 10 to 40 parts by weight, or 10 to 30 parts by weight relative to 100 parts by weight of the diamine component.

[0052] The diamine component may include a diamine compound other than an alicyclic diamine. Specifically, in one embodiment, the polyimide resin is obtained by imidizing a polyamic acid, a reactant of a tetracarboxylic dianhydride component and a diamine component, as monomer components. The diamine component includes an alicyclic diamine and a diamine other than an alicyclic diamine. Using a diamine other than an alicyclic diamine prevents gelation and, preferably, allows the preparation of a varnish as a cleaning layer-forming composition, resulting in a varnish having excellent processability when formed into a sheet.

[0053] The content of the diamine compound other than the alicyclic diamine in the diamine component for forming the polyamic acid may be, for example, 50 to 95 parts by weight, 60 to 90 parts by weight, or 70 to 90 parts by weight relative to 100 parts by weight of the diamine component.

[0054] Examples of diamine compounds other than alicyclic diamines include diamine compounds having at least two amine-structured terminals 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. As the diamine compound, dimer diamines can be used.

[0055] Any appropriate PE diamine compound can be used. 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 multiple structures thereof. More specifically, examples of PE diamine compounds include PE diamine compounds prepared from ethylene oxide, propylene oxide, polytetramethylene glycol, polyamines, or mixtures thereof, each having at least two terminal amine structures. Structural units derived from PE diamine compounds can serve as soft segments in polyimide resins.

[0056] The content of PE diamine in the monomer components used to form 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 is easily varnished can be obtained.

[0057] The content of PE diamine in the diamine component used to form 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 is easily varnished can be obtained.

[0058] Examples of the aliphatic diamine include ethylenediamine, hexamethylenediamine, 1,8-diaminodecane, 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.

[0059] Examples of the aromatic diamine 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.

[0060] Examples of the tetracarboxylic dianhydride component 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 one or two or more.

[0061] Examples of the organic solvent (reaction solvent) used in the reaction of 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.

[0062] The reaction temperature of tetracarboxylic dianhydride and diamine is preferably 20°C or higher, more preferably 20°C to 100°C.

[0063] The imidization of the polyamic acid is typically performed by heat treatment in an inert atmosphere (typically a vacuum or nitrogen atmosphere). The heat treatment temperature is preferably 150°C or higher, more preferably 180°C to 450°C.

[0064] 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 this range, the effects of the present invention are significant. The glass transition temperature (Tg) is measured using a thermomechanical analyzer (TMA). Details of the measurement method are described below.

[0065] The cleaning layer may contain any appropriate other components within the range that does not impair the effects of the present invention. Examples of such other components include heat-resistant resins, surfactants, plasticizers, antioxidants, conductivity-imparting agents, ultraviolet absorbers, and light stabilizers.

[0066] The thickness of the cleaning layer is preferably 1 μm to 100 μm, more preferably 1 μm to 50 μm, further preferably 1 μm to 30 μm, and particularly preferably 1 μm to 20 μm.

[0067] In one embodiment, the cleaning layer has substantially no adhesive force. Specifically, the 180° peeling strength A, as specified in JIS-Z-0237, to 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° peeling strength A, as specified in JIS-Z-0237, of the cleaning layer to the mirror surface of a silicon wafer is within this range, the cleaning layer has substantially no adhesive force, which can reduce the adhesion between the cleaning layer and, for example, the contact portion of the conveying device within a substrate processing apparatus. As a result, substrates can be transported reliably and the conveying device is less susceptible to damage.

[0068] The 180 degree peeling adhesion B of the cleaning layer to the mirror surface of dummy wafer is preferably more than 2N / 10mm, more preferably more than 3N / 10mm, further preferably more than 3.5N / 10mm, particularly preferably more than 5N / 10mm, most preferably more than 7N / 10mm.When 180 degree peeling adhesion B is in the above range, for example, the adhesion of the cleaning layer and the conveying members such as dummy wafer becomes high, and the cleaning layer is difficult for peeling from the conveying members such as dummy wafer during cleaning. The higher the 180 degree peeling adhesion B to the mirror surface of dummy wafer, the more preferred, but its upper limit is, for example, 20N / 10mm (preferably 30N / 10mm, more preferably 50N / 20mm).For 180 degree peeling adhesion B, for example, the cleaning layer is formed at the mirror surface of the silicon wafer as dummy wafer and measured. The measuring method of 180 degree peeling adhesion B is described later.

[0069] The storage modulus of the cleaning layer at 25°C can be 100 MPa to 2500 MPa, 100 MPa to 2000 MPa, 100 MPa to 1500 MPa, or 100 MPa to 1000 MPa. Preferably, it is 100 MPa to 1000 MPa. Within this range, a cleaning sheet with significantly superior foreign matter removal performance can be obtained. The method for measuring the storage modulus is described below.

[0070] The storage elastic modulus of the cleaning layer at 150°C can be 80 MPa to 2000 MPa, or 100 MPa to 1000 MPa. Preferably, it is 100 MPa to 1000 MPa. Within this range, a cleaning sheet with excellent foreign matter removal performance can be obtained. In the present invention, it is preferred that the storage elastic modulus sufficient to achieve optimal foreign matter removal performance be maintained even in high-temperature environments.

[0071] The storage elastic 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.

[0072] The number of cleaning layer residues on the mirror surface of the dummy wafer obtained by the cross-hatch method is preferably 15 / 25 or greater, more preferably 18 / 25 or greater, even more preferably 20 / 25 or greater, particularly preferably 23 / 25 or greater, and most preferably 25 / 25 or greater. When the number of cleaning layer residues on the mirror surface of the dummy wafer obtained by the cross-hatch method is within the above range, for example, the cleaning layer adheres more closely to conveying members such as the dummy wafer, making it less likely that the cleaning layer will peel off from conveying members such as the dummy wafer during cleaning.

[0073] The number of residues of the cleaning layer obtained by the grid method on the mirror surface of the dummy wafer can be measured, for example, as follows: using a cutting tool, 6 parallel cuts are made on the blank at an interval of 2 mm on the test surface, and then 6 parallel cuts are made at an interval of 2 mm in a manner perpendicular to the cuts to make 25 checkerboards, and a tape with an adhesive force of 16N / 20mm (for example, "BT-315ST" manufactured by Nitto Denko Corporation) is strongly pressed against the checkerboard portion, and the end of the tape is peeled off at an angle of 45°, and the state of the checkerboard is compared with the standard diagram and evaluated, thereby measuring.

[0074] A-3. Support

[0075] The cleaning sheet may include a support, which may be a single layer or a multilayered body.

[0076] The thickness of the support may be any appropriate thickness within a range that does not impair the effects of the present invention, and is preferably 500 μm or less, more preferably 1 μm to 400 μm, further preferably 1 μm to 300 μm, particularly preferably 1 μm to 200 μm, and most preferably 1 μm to 100 μm.

[0077] Any appropriate material can be used as the material constituting the support, as long as the effects of the present invention are not impaired. 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, cellulose acetate, polycarbonate, polypropylene, and polyamide.

[0078] The physical properties of the support material, such as molecular weight, can be appropriately selected depending on the intended purpose.

[0079] The method for forming the support can be appropriately selected depending on the intended purpose.

[0080] In order to improve the adhesion and retention with adjacent layers, the surface of the support may be subjected to conventional surface treatments, such as chemical or physical treatments such as chromic acid treatment, ozone exposure, flame exposure, high voltage electric shock exposure, ionizing radiation treatment, and primer coating treatment.

[0081] The peel strength of the cleaning layer from the support at 23°C is, for example, 3 N / 10 mm or greater, preferably 3.5 N / 10 mm or greater, and more preferably 5 N / 10 mm or greater. A higher peel strength at 23°C from the support is preferred, but the upper limit is, for example, 50 N / 10 mm. The peel strength is measured according to the method for measuring "180° Peel Adhesion Strength B."

[0082] A-4. Adhesive layer

[0083] The cleaning sheet may include an adhesive layer. Any suitable material may be used as long as the effects of the present invention are not impaired. Examples of the adhesive layer include acrylic adhesives, silicone adhesives, rubber adhesives, and urethane adhesives.

[0084] The adhesive layer is provided for attaching to the mirror surface of the dummy wafer, for example. Thus, the cleaning sheet is attached to the dummy wafer as the conveying member, thereby forming the conveying member with a cleaning function according to the embodiment of the present invention.

[0085] The 180-degree peel strength C of the adhesive layer to the mirror surface of the dummy wafer, as specified in JIS-Z-0237, is preferably 10 N / 10 mm or greater, more preferably 15 N / 10 mm or greater, even more preferably 20 N / 10 mm or greater, particularly preferably 25 N / 10 mm or greater, and most preferably 30 N / 10 mm or greater. When the 180-degree peel strength C of the adhesive layer to the mirror surface of the dummy wafer, as specified in JIS-Z-0237, is within the above range, for example, the adhesive layer and the dummy wafer have increased adhesion, making it difficult for the cleaning sheet to be peeled off the dummy wafer during cleaning.

[0086] The thickness of the adhesive layer is preferably 1 μm to 200 μm, more preferably 2 μm to 100 μm, further preferably 3 μm to 80 μm, particularly preferably 4 μm to 60 μm, and most preferably 5 μm to 50 μm.

[0087] A-5. Protective film

[0088] The cleaning sheet of the present invention may have a protective film to protect the cleaning layer, support, adhesive layer, etc. The protective film can be peeled off at an appropriate stage.

[0089] Any appropriate material can be used as the material constituting the protective film, as long as the effects of the present invention are not impaired. Examples of the material 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.

[0090] The protective film may be subjected to any appropriate release treatment within a range that does not impair the effects of the present invention. The release treatment is typically performed using a release agent. Examples of release agents include silicone release agents, long-chain alkyl release agents, fluorine release agents, fatty acid amide release agents, and silica release agents.

[0091] The thickness of the protective film is preferably 1 μm to 100 μm.

[0092] The method for forming the protective film is appropriately selected depending on the intended purpose, and for example, the protective film can be formed by injection molding, extrusion molding, blow molding, or the like.

[0093] B. Method for manufacturing cleaning sheet

[0094] As a method for manufacturing a cleaning sheet according to an embodiment of the present invention, any appropriate manufacturing method can be adopted without prejudice to the effects of the present invention. As such a manufacturing method, for example, the following method can be cited: (1) the cleaning layer forming composition (varnish) comprising polyamic acid is cast on a support, and after uniformly forming a film using a spin coater or the like, the film is heated to form a cleaning layer directly on the support. Preferably, the following method can be cited: a cleaning layer forming composition (varnish) is applied to a support using a spin coater to form a film, the film is allowed to stand as needed, and further, heating and / or drying is performed as needed to form a cleaning layer on the support, thereby manufacturing a cleaning sheet according to an embodiment of the present invention.

[0095] 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.

[0096] The rotation speed when applying the cleaning layer-forming composition (varnish) to form a film using a spin coater is preferably 400 rpm or higher, more preferably 600 rpm or higher, and even more preferably 800 rpm or higher. From the perspective of further demonstrating the effects of the present invention, the upper limit of the rotation speed is preferably 3000 rpm or lower.

[0097] The spin time when the cleaning layer-forming composition (varnish) is applied and formed into a film using a spin coater is preferably 5 to 200 seconds, more preferably 10 to 150 seconds, and even more preferably 20 to 60 seconds.

[0098] In the method for producing a cleaning sheet according to an embodiment of the present invention, after the cleaning layer-forming composition (varnish) is applied to a support to form a film, the film is allowed to stand, thereby smoothing the varnish. The standing time is preferably 5 to 1000 seconds, more preferably 30 to 600 seconds, and even more preferably 100 to 400 seconds.

[0099] 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, followed by heating and / or drying. The heating or drying temperature is preferably 50°C to 200°C, more preferably 80°C to 150°C. The heating or drying time is preferably 100 seconds to 900 seconds, more preferably 300 seconds to 900 seconds, and even more preferably 600 seconds to 900 seconds.

[0100] In the method for manufacturing a cleaning sheet according to an embodiment of the present invention, a cleaning layer-forming composition (varnish) can be applied to form a film, heated, and dried, and then cured under a vacuum or nitrogen atmosphere. The curing temperature is preferably 200°C to 400°C, more preferably 250°C to 350°C. The heating or drying time is preferably 30 minutes to 300 minutes, more preferably 60 minutes to 200 minutes. During this curing step, the cleaning resin softens due to being heated to above the glass transition temperature, thereby improving its ability to follow the wafer surface and improving the adhesion between the wafer and the cleaning layer.

[0101] C. Conveying components with cleaning function

[0102] A conveying member with a cleaning function according to an embodiment of the present invention includes the above-described cleaning sheet and a conveying member.

[0103] Figure 4 This is a schematic cross-sectional view showing one embodiment of the conveying member with a cleaning function according to the present invention. Figure 4 In the embodiment, the transport member 300 with a cleaning function includes a cleaning sheet 100 and a transport member 200. When the cleaning sheet 100 includes an adhesive layer, the outermost layer of the cleaning sheet 100 on the transport member 200 side is preferably the adhesive layer.

[0104] As the conveying member, any appropriate conveying member may be used within the scope that 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 disks, and MR heads. Among these conveying members, semiconductor wafers (e.g., silicon wafers) are representative examples for cleaning the conveying device of wafers within a substrate processing apparatus.

[0105] [Example]

[0106] The present invention will be described in more detail below with reference to Examples and Comparative Examples. However, the present invention is not limited thereto. It should be noted that, in the following description, "parts" and "%" are by weight unless otherwise specified.

[0107] <Evaluation Method>

[0108] (1) Storage modulus

[0109] The storage modulus of the cleaning layer was measured using a solid viscoelasticity measuring apparatus (model RSAG-2, manufactured by TA Instruments Japan). Specifically, a test piece with a length of 30 mm (measurement length) and a width of 10 mm was cut out and the storage modulus of the test piece was measured using a solid viscoelasticity measuring apparatus (model RSAG-2, manufactured by TA Instruments Japan) at a frequency of 1 Hz, a heating rate of 10°C / min, and a chuck distance of 10 mm over a temperature range of 0°C to 200°C. The storage moduli at 25°C, 150°C, and 300°C are shown in Table 1.

[0110] (2) Tightness test

[0111] The adhesion of the cleaning layer to the mirror surface of the dummy wafer was evaluated by the cross-cut method.

[0112] Using a cutting tool, 6 parallel cuts were made on the adhesive layer at intervals of 2 mm on the blank, and then 6 parallel cuts were made at intervals of 2 mm in a manner perpendicular to the cuts to produce 25 checkerboards. A tape with an adhesive force of 16 N / 20 mm ("BT-315ST" manufactured by Nitto Denko Corporation) was crimped to the checkerboard portion, and the end of the tape was peeled off at an angle of 45° to measure the remaining checkerboards.

[0113] (3) Peel strength (180-degree peeling adhesive force B on the mirror surface of a dummy wafer)

[0114] The peel strength (180-degree peel adhesion B of the cleaning layer to the mirror surface of the dummy wafer) was measured using a tensile testing machine (trade name "Autograph AGS-J", manufactured by Shimadzu Corporation) on a sample piece measuring 10 mm wide by 100 mm long at an ambient temperature of 23°C, a peel angle of 180°, and a tensile speed of 10 mm / min.

[0115] The test piece was prepared by the following method.

[0116] A backing tape (trade name "BT-315", manufactured by Nitto Denko Corporation) is attached to the cleaning layer of the conveying member with a cleaning function (cleaning layer / dummy wafer (silicon wafer)) obtained in the embodiment or comparative example by a pressing operation in which a 2 kg roller is moved back and forth once. Thereafter, for the laminated body laminated with the backing tape, the tape and the cleaning layer are cut parallel to the thickness direction of the laminated body so that the width of the portion to which the tape is attached (the portion to be subjected to the peeling force test) becomes 10 mm and the length is at least 100 mm, and a cut is made. In this way, a cleaning layer sample piece with a backing tape (width 10 mm × length 100 mm) is prepared. For this sample piece, the peeling force when the cleaning layer is peeled off from the silicon wafer is measured under the conditions of an ambient temperature of 23°C, a peeling angle of 180° and a tensile speed of 10 mm / min.

[0117] (4) Glass transition temperature (Tg) of polyimide resin

[0118] The glass transition temperature (Tg) of the polyimide resin can be measured using a thermomechanical analyzer (TMA). As a TMA, for example, "TMA7100" manufactured by Hitachi High-Tech Science Corporation can be cited. In the measurement, the cleaning layer is cut into a width of 5 mm × a length of 30 mm, and the measurement mode is set to a tensile mode. The measurement is carried out under the conditions of a load of 50 mN, a heating rate of 5°C / min, a nitrogen atmosphere, and a measurement temperature range of 25°C to 400°C. Tg is obtained from the intersection of the extension lines of the straight line portions on the high temperature side and the low temperature side of the TMA curve.

[0119] (5) Cleanliness

[0120] The mirror surface of a 6-inch silicon wafer was exposed to air for 6 hours. This was used to determine the number of foreign particles on the contaminated 6-inch silicon wafer (Count 1). Next, the contaminated 6-inch silicon wafer was attached to a cleaning sheet, which was then peeled off. The number of foreign particles on the post-peeling mirror surface was then measured (Count 2). Dust removal performance was calculated using the following formula.

[0121] Dust removal performance (%) = [(Count1-Count2) / Count1] × 100

[0122] Based on the above-mentioned dust removal performance, the cleaning performance was evaluated according to the following criteria.

[0123] ◎ (Excellent): Dust removal rate is more than 70%

[0124] ○ (Good): Dust removal performance is 50% or more and less than 70%

[0125] △ (OK): Dust removal efficiency is 20% or more and less than 50%

[0126] × (Not acceptable): Cleaning layer adheres to the mirror surface / Dust removal performance is less than 20%

[0127] [Example 1]

[0128] 2.4 parts by weight of a diamine monomer (4,4'-DPE, 4,4'-diaminodiphenyl ether) and a polyetheramine (D-2000, H2N-CH(CH3)-(O-CH2-CH(CH3)) as an amine component were added. n 3 parts by weight of NH2 (JEFFAMINE D-2000, manufactured by HUNTSMAN, molecular weight 2000, n = approximately 33) and 0.3 parts by weight of an alicyclic diamine ("NBDA" or norbornanediamine in the table) were dissolved in 43 parts by weight of dimethylacetamide. Subsequently, 3.6 parts by weight of dicarboxylic dianhydride (pyromellitic dianhydride) were added and reacted to obtain Varnish A.

[0129] This varnish A was applied to the entire mirror surface of a 12-inch silicon wafer by spin coating (1000 prm×30 sec).

[0130] Next, after drying at 110°C for 10 minutes using a hot plate, it was cured in a vacuum drying oven at 300°C for 180 minutes to obtain a conveying component A (cleaning layer / dummy wafer (silicon wafer)) with a cleaning function and a cleaning layer formed in a manner covering the entire surface of one side of the silicon wafer.

[0131] The obtained transport member with a cleaning function was subjected to the above-mentioned evaluation. The results are shown in Table 1.

[0132] [Examples 2 to 7, Comparative Example 1, Reference Examples 1 and 2]

[0133] A conveying member with a cleaning function was obtained in the same manner as in Example 1, except that the amounts of each component were adjusted as shown in Table 1. The obtained conveying member with a cleaning function was subjected to the above-mentioned evaluation. The results are shown in Table 1. Note that in Reference Examples 1 and 2, cracks occurred, and the cleaning layer could not be formed.

[0134] [Table 1]

[0135]

[0136] As is clear from Table 1, the Examples exhibited excellent foreign matter removal performance, as well as excellent results in the adhesion test and the peel strength test (180-degree peel strength B of the cleaning layer to the mirror surface of a dummy wafer), indicating that a cleaning sheet with excellent transport performance was obtained. On the other hand, the Comparative Examples exhibited poor results in the adhesion test and the peel strength test.

[0137] Industrial applicability

[0138] The cleaning sheet and the transport member with a cleaning function of the present invention are suitable for cleaning substrate processing equipment such as various manufacturing equipment and inspection equipment.

Claims

1. A cleaning sheet comprising a cleaning layer. The cleaning layer comprises a polyimide resin, This polyimide-based resin includes a structural unit derived from a diamine having an alicyclic skeleton.

2. The cleaning sheet according to claim 1, wherein The content ratio of the structural unit derived from the diamine having an alicyclic skeleton is 5 to 20 parts by weight relative to 100 parts by weight of the polyimide resin.

3. The cleaning sheet according to claim 1, wherein The alicyclic skeleton has 4 to 16 carbon atoms.

4. The cleaning sheet according to claim 1, wherein The diamine having an alicyclic skeleton has a norbornane skeleton.

5. The cleaning sheet according to claim 1, wherein The glass transition temperature (Tg) of the polyimide resin is 250°C to 300°C. The cleaning sheet according to claim 1 , wherein: The storage modulus of the cleaning layer at 25° C. is 100 MPa to 1000 MPa. 7 . The cleaning sheet according to claim 1 , further comprising a support disposed adjacent to the cleaning layer. 8 . A conveying member with a cleaning function, comprising the cleaning sheet according to claim 1 and a conveying member.

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