Cleaning sheets and conveying components with cleaning functions

Abstract

The objective of this invention is to provide a cleaning sheet with excellent foreign matter removal performance and to prevent the cleaning layer from detaching. An embodiment of the cleaning sheet of this invention includes a cleaning layer comprising a polyimide resin containing structural units having an alicyclic backbone, the polyimide resin comprising structural units derived from tetracarboxylic dianhydrides having an alicyclic backbone.

Description

Technical Field

[0001] This invention relates to a cleaning sheet and a conveying component with cleaning function. Prior Technology

[0002] In various substrate processing equipment, such as manufacturing or inspection equipment for semiconductors, flat panel displays, and printed circuit boards, foreign objects are highly contraindicated. The substrate is transported while a transfer device (e.g., a work tray) physically contacts it. If foreign objects adhere to the transfer device, they will gradually contaminate subsequent substrates. Therefore, the equipment must be stopped periodically for cleaning. This results in either reduced processing efficiency or the need for significant labor for cleaning.

[0003] To overcome this problem, a method has been proposed to remove foreign matter adhering to the conveying device by conveying a plate-shaped component within a substrate processing apparatus (see Patent Document 1). This method eliminates the need to stop the substrate processing apparatus for cleaning, thus avoiding the problem of reduced processing efficiency. However, this method cannot adequately remove foreign matter adhering to the conveying device.

[0004] Furthermore, a method for removing foreign matter attached to a transfer device by transferring a substrate with an adhesive material attached as a cleaning member within a substrate processing apparatus is proposed (see Patent Document 2). This method exhibits superior foreign matter removal performance compared to the method described in Patent Document 1. However, in the method described in Patent Document 2, the adhesive material may adhere too strongly to the contact portion of the transfer device, making separation impossible. This can result in problems such as inability to reliably transfer the substrate with the adhesive material attached, damage to the transfer device, and contamination of the transfer device. On the other hand, if the adhesion between the adhesive material and the transfer device is too weak, the removal efficiency of the foreign matter by the cleaning member may be reduced, resulting in insufficient cleaning effectiveness. [Previous Technical Documents] [Patent Literature]

[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 Publication No. 2007-307521 [Patent Document 4] Japanese Patent Application Publication No. 2010-259970 Summary of the Invention

[0006] [The problem the invention aims to solve] The objective of this invention is to provide a cleaning sheet with excellent foreign matter removal and conveying performance. [Technical means to solve the problem]

[0007] 1. The cleaning sheet according to an embodiment of the present invention comprises a cleaning layer, the cleaning layer comprising a polyimide resin containing structural units having an alicyclic backbone, the polyimide resin comprising structural units derived from tetracarboxylic dianhydride having an alicyclic backbone. 2. The cleaning tablet as described in 1 above, wherein the ratio of the structural unit having an alicyclic skeleton to 100 parts by weight of the polyimide resin may be 5 to 50 parts by weight. 3. The cleaning sheet as described in 1 or 2 above, wherein the polyimide resin may further include structural units derived from diamines having an alicyclic backbone. 4. The cleaning tablet described in any one of 1 to 3 above, wherein the content ratio of the structural unit derived from tetracarboxylic acid dianhydride having an alicyclic backbone is 5 to 40 parts by weight relative to 100 parts by weight of the polyimide resin. 5. The cleaning tablet described in any of items 1 to 4 above, wherein the alicyclic dianhydride having an alicyclic skeleton may have 4 to 16 carbon atoms in its alicyclic skeleton. 6. The cleaning sheet described in any one of items 1 to 5 above, wherein the glass transition temperature (Tg) of the polyimide resin is 250°C to 300°C. 7. The cleaning sheet as described in any one of items 1 to 6 above, wherein the storage elastic modulus of the cleaning layer at 25°C can be 100 MPa to 1000 MPa. 8. The cleaning sheet described in any of items 1 to 7 above may further have a support body disposed adjacent to the cleaning layer. 9. The cleaning-functional conveying member of the present invention has a cleaning sheet and a conveying member as described in any one of 1 to 8 above. [Effects of the Invention]

[0008] According to the present invention, a cleaning sheet with excellent foreign matter removal and conveying performance can be provided. Simple Explanation of the Diagram

[0009] Figure 1 is a schematic cross-sectional view of a cleaning sheet according to an embodiment of the present invention. Figure 2 is a schematic cross-sectional view of the cleaning sheet according to an embodiment of the present invention. Figure 3 is a schematic cross-sectional view of the cleaning sheet according to an embodiment of the present invention. Figure 4 is a schematic cross-sectional view of a conveying component with cleaning function according to an embodiment of the present invention. Implementation

[0010] [A.] [Cleaning tablets] [] [A-1.] [summary] [] The cleaning sheet according to an embodiment of the present invention has a cleaning layer. The cleaning sheet according to an embodiment of the present invention may consist of only the cleaning layer, or it may have other layers.

[0011] Figure 1 is a schematic cross-sectional view showing one embodiment of the cleaning sheet according to an embodiment of the present invention. In Figure 1, the cleaning sheet 100 has a cleaning layer 10 and a protective film 20 disposed on at least one side of the cleaning layer 10. The protective film 20 may be provided for the purpose of protecting the cleaning layer 10, or it may be omitted depending on the purpose. That is, the cleaning sheet of the present invention may consist only of the cleaning layer 10.

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

[0013] The cleaning sheet according to embodiments of the present invention may further include a support disposed adjacent to the cleaning layer. In one embodiment, the support is disposed in contact with the cleaning layer. The support may be a transport support such as a dummy wafer. FIG3 is a schematic cross-sectional view showing another embodiment of the cleaning sheet according to embodiments of the present invention. In FIG3, the cleaning sheet 100 sequentially includes 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, or it may be omitted depending on the purpose. Also, the adhesive layer 30 may be omitted.

[0014] [A-2.] [Clean layer] [] The aforementioned cleaning layer comprises a polyimide resin. The content of the polyimide resin in the cleaning layer relative to 100 parts by weight is preferably 50 to 100 parts by weight, more preferably 70 to 100 parts by weight, further preferably 90 to 100 parts by weight, even more preferably 95 to 100 parts by weight, and most preferably 98 to 100 parts by weight. The polyimide resin preferably has soft segments. Soft segments are segments that impart flexibility to the polymer; for example, they may be segments with long-chain linear groups or long-chain branched groups in the main chain, which are flexible and elastic.

[0015] The aforementioned polyimide resin comprises structural units having an alicyclic backbone. A cleaning layer formed using a polyimide resin comprising structural units having an alicyclic backbone exhibits superior elasticity and excellent foreign matter removal and conveying performance at the temperature (e.g., 0°C to 200°C) in the environment where the cleaning sheet is used. Furthermore, less foreign matter is generated from the cleaning layer, preventing contamination of the object being cleaned. Moreover, the polyimide resin exhibits flexibility due to heating during its formation, such as heating for amide formation (e.g., heating at 250°C to 300°C), resulting in a cleaning sheet with excellent adhesion to layers adjacent to the cleaning layer. Especially in the case of a polyimide resin comprising structural units derived from tetracarboxylic dianhydrides having an alicyclic backbone, although the mechanism is not fully understood, the surface free energy between the cleaning layer and layers adjacent to it increases, resulting in a cleaning sheet with such excellent adhesion. For example, a cleaning sheet with excellent adhesion between the support and the cleaning layer can be obtained. This type of cleaning sheet is particularly advantageous in preventing the cleaning layer from detaching during use and transportation. Furthermore, it is also advantageous in suppressing peeling at the ends of the cleaning layer.

[0016] In polyimide resins, the proportion of structural units having an alicyclic backbone relative to 100 parts by weight of the polyimide resin is preferably 3 to 50 parts by weight, more preferably 5 to 50 parts by weight, further preferably 8 to 50 parts by weight, and even more preferably 10 to 45 parts by weight. If this range is met, the aforementioned effects are significant.

[0017] In the monomer components used to form the above-mentioned polyamide, the content ratio of monomers having an alicyclic backbone relative to 100 parts by weight is preferably 3 to 50 parts by weight, more preferably 5 to 50 parts by weight, further preferably 8 to 50 parts by weight, and further preferably 10 to 45 parts by weight.

[0018] Typically, polyimide resins are obtained by amide-imidizing polyamide. Polyamide can be obtained by using tetracarboxylic dianhydride and diamine as monomer components, and reacting them in substantially equal molar ratios in any suitable organic solvent.

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

[0020] The alicyclic tetracarboxylic dianhydride component described above has an alicyclic skeleton with 4 to 16 carbon atoms, preferably 4 to 10. If it falls within this range, the above-mentioned effects are significant.

[0021] Examples of alicyclic tetracarboxylic dianhydrides include 1,2,3,4-cyclobutanetetracarboxylic dianhydrides, substituted cyclobutanetetracarboxylic dianhydrides, 2,3,5-tricarboxycyclopentylacetic acid dianhydrides, 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-tetracarboxylic bicyclo[3.3.0]octane-2:4,6:8-dianhydrides, cyclopentanetetracarboxylic dianhydrides, cyclohexanetetracarboxylic dianhydrides, and 3,5,6-tricarboxylic-2-carboxymethylnorhexane-2:3,5:6-dianhydrides.

[0022] In polyimide resins, the content ratio of structural units derived from alicyclic tetracarboxylic dianhydride relative to 100 parts by weight of 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. Using alicyclic tetracarboxylic dianhydride at this content ratio can prevent defects such as breakage, thereby better forming a cleaning layer. Furthermore, by setting the content ratio of structural units derived from alicyclic tetracarboxylic dianhydride relative to 100 parts by weight of the polyimide resin to 5 parts by weight or more, the effect of using alicyclic tetracarboxylic dianhydride is significant.

[0023] In the monomer components used to form the above-mentioned polyamide, the content ratio of alicyclic tetracarboxylic dianhydride relative to 100 parts by weight of the monomer component 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.

[0024] In the tetracarboxylic dianhydride component used to form the above-mentioned polyacrylic acid, the content ratio of alicyclic tetracarboxylic dianhydride relative to 100 parts by weight of the alicyclic tetracarboxylic dianhydride component can be, for example, 5 parts by weight to 100 parts by weight. This ratio can be 8 parts by weight to 80 parts by weight, or 10 parts by weight to 60 parts by weight, or 10 parts by weight to 50 parts by weight.

[0025] The aforementioned tetracarboxylic dianhydride component may include tetracarboxylic dianhydrides other than alicyclic tetracarboxylic dianhydrides. That is, in one embodiment, the aforementioned polyimide-based resin is a resin obtained by using a tetracarboxylic dianhydride component and a diamine component as monomer components, and imidizing polyamide acid, which is a reactant of the monomer component; the tetracarboxylic dianhydride component includes alicyclic tetracarboxylic dianhydrides and tetracarboxylic dianhydrides other than alicyclic tetracarboxylic dianhydrides.

[0026] In the tetracarboxylic dianhydride component used to form the above-mentioned polyacrylamide, the proportion of tetracarboxylic dianhydride other than alicyclic tetracarboxylic dianhydride relative to 100 parts by weight of the tetracarboxylic dianhydride component can be, for example, 0 to 95 parts by weight. This proportion can be 20 to 92 parts by weight, or 40 to 90 parts by weight.

[0027] Examples of the aforementioned tetracarboxylic acid dianhydrides include 3,3',4,4'-biphenyltetracarboxylic acid dianhydride, 2,2',3,3'-biphenyltetracarboxylic acid dianhydride, 3,3',4,4'-benzophenonetetracarboxylic acid dianhydride, 2,2',3,3'-benzophenonetetracarboxylic acid dianhydride, 4,4'-oxophthalic acid 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)granite dianhydride, bis(3,4-dicarboxyphenyl)granite dianhydride, pyrocalcite dianhydride, and ethylene glycol bis(triphenyl)carboxylic acid dianhydride. There may be one or more of these.

[0028] In one embodiment, the diamine component comprises a diamine having an alicyclic backbone (hereinafter also simply referred to as an alicyclic diamine). That is, the polyimide resin may also contain structural units derived from a diamine having an alicyclic backbone.

[0029] The alicyclic diamine described above has an alicyclic skeleton with 4 to 16 carbon atoms, preferably 4 to 10. If it falls within this range, the above-mentioned effects are significant.

[0030] Examples of the aforementioned alicyclic diamines 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-diamine benzoxane, and norethanediamine. These can be used alone or in combination of two or more.

[0031] In one embodiment, the aforementioned alicyclic diamine has a noralkyl skeleton. The above-mentioned effects are significant when an alicyclic diamine having a noralkyl skeleton is used. Examples of alicyclic diamines having a noralkyl skeleton include noralkyl diamine. Examples of noralkyl diamines include 2,5-noralkyl dimethylamine and 2,6-noralkyl dimethylamine.

[0032] In polyimide resins, the content ratio of structural units derived from alicyclic diamines relative to 100 parts by weight of the polyimide resin is, for example, 20 parts by weight or less, preferably 5 to 20 parts by weight, more preferably 5 parts by weight or more but less than 19 parts by weight, further preferably 6 to 17 parts by weight, and even more preferably 7 to 15 parts by weight. Using alicyclic diamines at this content ratio can prevent defects such as breakage and better form a cleaning layer. Furthermore, if the content ratio of structural units derived from alicyclic diamines relative to 100 parts by weight of the polyimide resin is set to 5 parts by weight or more, the effect of using the alicyclic diamine is significant.

[0033] In the monomer components used to form the above-mentioned polyamide, the content ratio of alicyclic diamine relative to 100 parts by weight of the monomer component is, for example, less than 20 parts by weight, preferably 5 to 20 parts by weight, more preferably more than 5 parts by weight but less than 19 parts by weight, and even more preferably 6 to 17 parts by weight, and even more preferably 7 to 15 parts by weight.

[0034] In the diamine component used to form the above-mentioned polyamide, the ratio of alicyclic diamine to 100 parts by weight of the diamine component can be, for example, 5 to 50 parts by weight. This ratio can also be 10 to 40 parts by weight, or 10 to 30 parts by weight.

[0035] The aforementioned diamine component may include diamine compounds other than alicyclic diamines. By using diamines other than alicyclic diamines, gelation can be prevented and the varnish used as a cleaning layer forming composition can be better adjusted, resulting in a varnish with excellent processability when sheet-forming.

[0036] In the diamine component used to form the above-mentioned polyamide, the proportion of diamine compounds other than alicyclic diamines relative to 100 parts by weight of the diamine component can be, for example, 50 to 95 parts by weight. This proportion can be 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 amine-structured ends and a polyether structure (hereinafter also referred to as PE diamine compounds), aliphatic diamines, and aromatic diamines. Among these, PE diamine compounds are preferred. Dimeric diamines can also be used as diamine compounds.

[0038] Any suitable 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 poly1,4-butanediol structure, and so on, terminal diamines having a plurality of such structures. More specifically, examples of PE diamine compounds include those prepared from ethylene oxide, propylene oxide, poly1,4-butanediol, polyamines, or mixtures thereof, having at least two amine-structured terminals. The structural units derived from the PE diamine compound can become soft segments in polyimide resins.

[0039] In the monomer components used to form the aforementioned polyamide, the content of PE diamine relative to 100 parts by weight of the monomer component is preferably 10 to 60 parts by weight, more preferably 12 to 50 parts by weight, further preferably 15 to 45 parts by weight, and even more preferably 20 to 40 parts by weight. 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.

[0040] In the diamine component used to form the aforementioned polyamide, the content ratio of PE diamine relative to 100 parts by weight of the diamine component is preferably 20 parts by weight to 80 parts by weight, more preferably 25 parts by weight to 75 parts by weight, and even more preferably 30 parts by weight to 70 parts by weight. 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.

[0041] Examples of aliphatic diamines 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-tetramethylsiloxane (α,ω-bisaminopropyltetramethylsiloxane). The molecular weight of the aliphatic diamine is preferably 50 to 1,000,000, 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 sulfide, 3,3'-diaminodiphenyl sulfide, 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'-diaminodibenzophenone.

[0043] Organic solvents (reaction solvents) used in the reaction of tetracarboxylic dianhydride and diamine can include, for example, N,N-dimethylacetamide, N-methyl-2-pyrrolidone, and N,N-dimethylformamide. To adjust the solubility of the raw materials, non-polar solvents (such as toluene or xylene) may also be used.

[0044] The preferred reaction temperature for tetracarboxylic acid dianhydride and diamine is above 20°C, and more preferably 20°C to 100°C.

[0045] Typically, the amide formation of polyamide is carried out by heat treatment in an inert atmosphere (typically a vacuum or nitrogen atmosphere). The heat treatment temperature is preferably above 150°C, and more preferably between 180°C and 450°C.

[0046] The glass transition temperature (Tg) of the aforementioned 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. The invention exhibits significant advantages within this range. The glass transition temperature (Tg) is measured using a thermomechanical analysis (TMA) apparatus. Details of the measurement method are as follows.

[0047] Within the scope of not impairing the effects of the present invention, any other suitable components may be included in the cleaning layer. Examples of such other components include 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, even more preferably 1 μm to 30 μm, and even more preferably 1 μm to 20 μm.

[0049] In one embodiment, the cleaning layer is substantially non-adhesive. Specifically, the 180° peel adhesion A to the mirror surface of the silicon wafer, as specified in JIS-Z-0237, is preferably less than 0.20 N / 10 mm, and more preferably 0.01 to 0.10 N / 10 mm. If the 180° peel adhesion A of the cleaning layer to the mirror surface of the silicon wafer, as specified in JIS-Z-0237, is within this range, the cleaning layer is substantially non-adhesive, which reduces the adhesion of the cleaning layer to the contact portion with, for example, a transport device within a substrate processing apparatus. As a result, the substrate can be transported reliably, and the transport device is less prone to breakage.

[0050] The 180-degree peel adhesion B of the cleaning layer to the mirror surface of the dummy wafer is preferably 2 N / 10 mm or more, more preferably 3 N / 10 mm or more, further 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, the adhesion between the cleaning layer and the transport components such as the dummy wafer is improved, and the cleaning layer is less likely to peel off from the transport components such as the dummy wafer during the cleaning process. The higher the 180-degree peel adhesion B to the mirror surface of the dummy wafer, the better, but its 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 the silicon wafer used as the dummy wafer. The method for measuring the 180-degree peel adhesion B is as follows.

[0051] The storage elastic 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 these ranges, a cleaning sheet with significantly superior foreign matter removal performance can be obtained. The method for determining the storage elastic modulus is as follows.

[0052] 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 this invention, it is preferable to maintain a storage elastic modulus that allows for better foreign matter removal performance even under high-temperature environments.

[0053] The storage elastic modulus of the cleaning layer at 300°C can 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 this range, a cleaning sheet with excellent adhesion between the support and the cleaning layer can be obtained.

[0054] Regarding the cleaning layer, the residual number of the cleaning layer obtained by the cross-cutting method relative to the mirror surface of the dummy wafer is preferably 15 / 25 or more, more preferably 18 / 25 or more, further preferably 20 / 25 or more, especially preferably 23 / 25 or more, and most preferably 25 / 25 or more. If the residual number of the cleaning layer obtained by the cross-cutting method relative to the mirror surface of the dummy wafer is within the above range, the adhesion between the cleaning layer and the transport components such as the dummy wafer is higher, and the cleaning layer is less likely to peel off from the transport components such as the dummy wafer during the cleaning process.

[0055] The number of residual clean layers obtained by the cross-cutting method relative to the mirror surface of the dummy wafer can be determined, for example, by the following method: using a dicing tool, make 6 parallel cuts at 2 mm intervals relative to the substrate on the test surface. Then, make 6 parallel cuts at 2 mm intervals in the same manner orthogonal to the cuts, thereby creating 25 grids. A tape with an adhesion of 16 N / 20 mm (such as "BT-315ST" manufactured by Nitto Denko Co., Ltd.) is firmly pressed onto the grid portion. The end of the tape is peeled off at a 45° angle in one go. The state of the grid is compared with a standard diagram and evaluated.

[0056] [A-3.] [Supporting Body] [] The cleaning sheet described above may also have a support. The support may be a single layer or multiple layers.

[0057] The thickness of the support can be any suitable thickness within the range that does not impair the effects of the present invention. Preferably, the thickness is 500 μm or less, more preferably 1 μm to 400 μm, further preferably 1 μm to 300 μm, even more preferably 1 μm to 200 μm, and most preferably 1 μm to 100 μm.

[0058] As the material constituting the support, any suitable material can be used within the scope of not impairing the effects of the present invention. Examples of the support include films of plastics, engineering plastics, or super-engineering plastics. Specific examples of plastics, engineering plastics, or super-engineering plastics include polyimide, polyethylene, polyethylene terephthalate, acetyl cellulose, polycarbonate, polypropylene, and polyamide.

[0059] The molecular weight and other physical properties of the support material can be appropriately selected according to the purpose.

[0060] The method of forming the support can be appropriately selected according to the purpose.

[0061] To improve adhesion and retention with adjacent layers, conventional surface treatments can be applied to the surface of the support, such as chemical or physical treatments like chromic acid treatment, ozone exposure, flame exposure, high-voltage electric shock exposure, and ionizing radiation treatment, as well as treatments using primers.

[0062] The peel force of the cleaning layer on 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. A higher peel force of the cleaning layer on the support at 23°C is preferred, but its upper limit is, for example, 50 N / 10 mm. The peel force is measured according to the method for measuring "180-degree peel adhesion B".

[0063] [A-4.] [Adhesive layer] [] The cleaning sheet described above may also have an adhesive layer. Any suitable material can be used as the material constituting this adhesive layer, provided it does not impair the effects of the present invention. Examples of materials for the adhesive layer include acrylic adhesives, polysiloxane adhesives, rubber adhesives, and urethane adhesives.

[0064] An adhesive layer is provided, for example, for attaching to the mirror surface of a dummy wafer. In this way, attaching the aforementioned cleaning sheet to the dummy wafer, which serves as a transport member, creates a transport member with cleaning function according to an embodiment of the present invention.

[0065] The 180-degree peel adhesion 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 more, more preferably 15 N / 10 mm or more, further 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 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, if the adhesion between the adhesive layer and the dummy wafer is improved, the cleaning sheet is less likely to peel off from the dummy wafer during the cleaning process.

[0066] The thickness of the 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] [] To protect the cleaning layer, support, and adhesive layer, the cleaning sheet of the present invention may also have a protective film. The protective film can be peeled off at an appropriate stage.

[0068] As the material constituting the protective film, any suitable material may be used within the scope that does not impair the effects of the present invention. Examples of materials for the protective film include polyethylene, polypropylene, polybutene, polybutadiene, polymethylpentene and other polyolefins, polyvinyl chloride, vinyl chloride copolymer, polyethylene terephthalate, polybutylene terephthalate, polyurethane, ethylene vinyl acetate copolymer, ionomer resin, ethylene-(meth)acrylic acid copolymer, ethylene-(meth)acrylic acid copolymer, polystyrene, polycarbonate, polyimide, fluoropolymer, etc.

[0069] The protective film can be subjected to any suitable peeling process within the scope of not compromising the effects of the present invention. Typically, the peeling process is carried out by a peeling agent. Examples of peeling agents include polysiloxane-based peeling agents, long-chain alkyl-based peeling agents, fluorinated peeling agents, aliphatic amide-based peeling agents, and silicon dioxide-based peeling agents.

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

[0071] The method of forming the protective film is selected appropriately according to the purpose. For example, it can be formed by injection molding, extrusion molding, blow molding, etc.

[0072] [B.] [Manufacturing Method of Cleaning Tablets] [] As a method for manufacturing the cleaning sheet according to an embodiment of the present invention, any suitable manufacturing method may be used within the scope of not impairing the effects of the present invention. For example, such a manufacturing method may be described as follows: (1) casting a cleaning layer forming composition (varnish) containing the above-mentioned polyacrylic acid onto a support, uniformly forming a film using a spin coater or the like, and then heating it to directly form a cleaning layer on the support. A preferred method is described as follows: applying the cleaning layer forming composition (varnish) onto the support using a spin coater and forming a film, allowing it to stand as needed, and then heating and / or drying as needed to form a cleaning layer on the support, thereby manufacturing the cleaning sheet according to an embodiment of the present invention.

[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] When applying and forming a film-cleaning layer composition (varnish) using a rotary coater, the rotation speed is preferably 400 rpm or more, more preferably 600 rpm or more, and even more preferably 800 rpm or more. In terms of further demonstrating the effects of the present invention, the upper limit of the above-mentioned rotation speed is preferably 3000 rpm or less.

[0075] The rotation time for applying the cleaning layer forming composition (varnish) to the rotary coater and forming a film is preferably 5 seconds to 200 seconds, more preferably 10 seconds to 150 seconds, and even more preferably 20 seconds to 60 seconds.

[0076] In the method for manufacturing the cleaning sheet according to an embodiment of the present invention, a cleaning layer forming composition (varnish) is applied to a support and formed into a film, and then left to stand, thereby making the varnish smoother. The standing time is preferably 5 seconds to 1000 seconds, more preferably 30 seconds to 600 seconds, and even more preferably 100 seconds to 400 seconds.

[0077] In the method for manufacturing the cleaning sheet according to the embodiments of the present invention, heating and / or drying can also be performed after the cleaning layer forming composition (varnish) is coated and formed into a film. 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.

[0078] In the method for manufacturing the cleaning sheet according to the embodiments of the present invention, a cleaning layer forming composition (varnish) may be coated, formed into a film, heated, 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. In this curing step, the cleaning resin is heated to above the glass transition temperature, thereby softening it, improving its conformability to the wafer surface, and increasing the adhesion between the wafer and the cleaning layer.

[0079] [C.] [Transfer components with cleaning function] [] The conveying member with cleaning function according to an embodiment of the present invention includes the above-mentioned cleaning sheet and conveying member.

[0080] Figure 4 is a schematic cross-sectional view showing one embodiment of the cleaning-functional conveying member of the present invention. In Figure 4, the cleaning-functional conveying member 300 includes a cleaning sheet 100 and a conveying member 200. When the cleaning sheet 100 has an adhesive layer, it is preferable that the outermost layer of the cleaning sheet 100 on the conveying member 200 side is the adhesive layer.

[0081] As a transport component, any suitable transport component can be used within the scope of not impairing the effects of the present invention. Examples of such transport components include semiconductor wafers (e.g., silicon wafers), substrates for flat panel displays such as LCDs and PDPs, optical discs, MR heads, etc. Among these transport components, in the case of a wafer transport device whose purpose is to clean the substrate processing apparatus, semiconductor wafers (e.g., silicon wafers) can be representatively 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 thereto. Furthermore, in the following description, unless otherwise explicitly stated, "parts" and "%" are based on weight.

[0083] <Evaluation Methods> (1) Store elastic modulus The stored elastic modulus of the clean layer was determined using a solid viscoelasticity measuring apparatus (model RSAG-2, manufactured by TA Instruments Japan Co., Ltd.). Specifically, a sample 30 mm long (measurement length) and 10 mm wide was cut. The stored elastic modulus of the sample was measured using the solid viscoelasticity measuring apparatus (model RSAG-2, manufactured by TA Instruments Japan Co., Ltd.) at a frequency of 1 Hz, a heating rate of 10 °C / min, and a clamping distance of 10 mm, within a temperature range of 0 °C to 200 °C. The stored elastic moduli at 25 °C, 150 °C, and 300 °C are shown in Table 1. (2) Close contact test The adhesion of the cleaning layer to the mirror surface of the dummy wafer was evaluated by cross-cutting method. Using a cutting tool, make six parallel cuts at 2 mm intervals relative to the substrate in the adhesive layer. Then, make six more parallel cuts at 2 mm intervals, orthogonal to the previous cuts, to create 25 grids. Press a tape with an adhesive strength of 16 N / 20 mm (such as "BT-315ST" manufactured by Nitto Denko Corporation) onto the grid portion. Peel off the end of the tape at a 45° angle and measure the remaining grid. (3) Peeling force (180-degree peel adhesion force on the mirror surface of the dummy wafer B) Using a tensile testing machine (trade name "Autograph AGS-J", manufactured by Shimadzu Corporation), the peel force (the 180-degree peel adhesion force B of the clean layer to the mirror surface of the dummy wafer) was measured on a specimen with a width of 10 mm and a length of 100 mm under the conditions of an ambient temperature of 23°C, a peel angle of 180° and a tensile speed of 10 mm / min. The test pieces were prepared using the following method. By pressing a 2 kg roller back and forth once, a backing tape (trade name "BT-315", manufactured by Nitto Denko Corporation) was applied to the cleaning layer of the cleaning-functional transport component (cleaning layer / dummy wafer (silicon wafer)) obtained in the examples or comparative examples. Subsequently, in the laminated body with the backing tape, the portion with the tape (the portion for which the peel force was tested) was cut parallel to the thickness direction of the laminate, with the tape being 10 mm wide and at least 100 mm long, to create a cut. A cleaning layer test piece (10 mm wide × 100 mm long) with the backing tape was thus prepared. For this test piece, the peel force when the cleaning layer was peeled from the silicon wafer was measured under the conditions of an ambient temperature of 23°C, a peel angle of 180°, and a tensile speed of 10 mm / min. (4) Glass transition temperature (Tg) of polyimide resins The glass transition temperature (Tg) of polyimide resins can be determined using a thermomechanical analysis (TMA) apparatus. For example, the TMA7100 manufactured by Hitachi High-Tech Co., Ltd. is suitable for this purpose. In the measurement, a clean layer is cut into pieces 5 mm wide and 30 mm long. The measurement mode is set to tensile mode, with 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. The Tg is determined by the intersection of the extended lines of the straight sections on the high-temperature and low-temperature sides of the TMA curve. (5) Cleanliness A 6-inch silicon wafer was exposed to the atmosphere for 6 hours to create a contaminated 6-inch silicon wafer. The number of foreign objects on its mirror surface was measured (Count1). Then, the mirror surface of the contaminated 6-inch silicon wafer was attached to a cleaning sheet, and subsequently peeled off. The number of foreign objects on the mirror surface of the peeled silicon wafer was measured (Count2). The dust removal performance was calculated using the following formula. Dust removal efficiency (%) = [(Count1 - Count2) / Count1] × 100 Based on the above dust removal performance, cleanliness is evaluated according to the following criteria. ◎(Excellent): Dust removal efficiency is above 70%. ○ (Good): Dust removal efficiency is above 50% but below 70%. Δ (Qualified): Dust removal efficiency is above 20% but below 50%. × (Unacceptable): Cleaning layer adheres to the mirror surface / Dust removal efficiency not reaching 20%.

[0084] [Example 1] 2.8 parts by weight of a diamine monomer ("4,4'-DPE", 4,4'-diaminodiphenyl ether in the table), which serves as the amine component, and 3 parts by weight of a polyetheramine ("D-2000", H2N-CH(CH3)-(O-CH2-CH(CH3))n-NH2, trade name "JEFFAMINE D-2000", manufactured by HUNTSMAN, molecular weight 2000, n=approximately 33) were dissolved in 50 parts by weight of dimethylacetamide. Subsequently, 3.2 parts by weight of an alicyclic tetracarboxylic dianhydride ("CBDA", 1,2,3,4-cyclobutanetetracarboxylic dianhydride in the table) were added to react and obtain varnish A. Varnish A was then applied to the entire mirror surface of a 12-inch silicon wafer using a spin coating method (1000 prm × 30 sec). Subsequently, after drying at 110°C for 10 minutes using a heating plate, it is cured at 300°C for 180 minutes in a vacuum drying oven to obtain a transport component A (cleaning layer / dummy wafer (silicon wafer)) with a cleaning function, which has a cleaning layer formed in a way that covers the entire surface of one of the silicon wafers. The obtained conveying components with cleaning functions were used for the above evaluation. The results are shown in Table 1.

[0085] [Examples 2-9, Comparative Example 1, Reference Example 1] The proportions of each component were set as shown in Table 1. Otherwise, a conveying member with cleaning function was obtained in the same manner as in Example 1. The obtained conveying member with cleaning function was subjected to the above evaluation. The results are shown in Table 1. Furthermore, the alicyclic diamine (NBDA) in the table is noralkyl diamine as the diamine component, and the dicarboxylic anhydride (PMDA) in the table is pyrocalcite dianhydride as the tetracarboxylic dianhydride component. Also, a cleaning layer could not be formed in Reference Example 1.

[0086] [Table 1] Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Raw material mixing quantity (parts by weight) diamine compounds (4,4'-DPE) 2.8 2.9 3.2 2.8 2.4 1.8 Alicyclic diamine (NBDA) - - - - 0.5 1 Dicarboxylic anhydride (PMDA) - 3.2 2 3 3 2.5 Alicyclic tetracarboxylic dianhydride (CBDA) 3.2 0.3 1.7 0.5 0.5 1 polyetheramine 3 3 3 3 3 3 Reaction solvent (DMAc) 50 40 50 45 40 40 Alicyclic monomer content ratio (%) 35 3 17 5 11 twenty two Alicyclic diamine content ratio (%) 0 0 0 0 5 11 alicyclic tetracarboxylic dianhydride content ratio (%) 35 3 17 5 5 11 Polyetheramine content ratio (%) 33 32 30 32 32 32 Tightness test (cross-cut) number of survivors / number of grids 25 / 25 19 / 25 25 / 25 25 / 25 25 / 25 25 / 25 Peeling force (180-degree peel adhesion B) (N / 10 mm) 7.8 4.8 7.3 5.3 6.8 7.8 Storage elastic modulus (MPa) Storage modulus of elasticity at 25°C 664 793 408 514 850 876 Storage modulus of elasticity at 150°C 337 423 220 221 445 415 Storage modulus of elasticity at 300°C 211 200 180 220 11 30 Tg (°C) of polyimide resins 260 300 270 270 270 260 Cleanliness ◎ ◎ ◎ ◎ ◎ ◎ Example 7 Example 8 Example 9 Comparative example 1 Reference Example 1 Raw material mixing quantity (parts by weight) diamine compounds (4,4'-DPE) 1.1 2.3 1.5 2.8 - Alicyclic diamine (NBDA) 1.5 0.5 1.1 - 2.1 Dicarboxylic anhydride (PMDA) 2 - - 3.6 - Alicyclic tetracarboxylic dianhydride (CBDA) 1.5 3.2 3.2 - 3.2 polyetheramine 3 3 3 3 4.6 Reaction solvent (DMAc) 40 40 40 43 50 Alicyclic monomer content ratio (%) 33 41 49 0 54 Alicyclic diamine content ratio (%) 16 6 13 0 twenty one alicyclic tetracarboxylic dianhydride content ratio (%) 16 36 36 0 32 Polyetheramine content ratio (%) 33 33 34 32 46 Tightness test (cross-cut) number of survivors / number of grids 25 / 25 25 / 25 25 / 25 0 / 25 - Peeling force (180-degree peel adhesion B) (N / 10 mm) 7.8 7.8 7.5 1.2 - Storage elastic modulus (MPa) Storage modulus of elasticity at 25°C 762 1200 830 600 - Storage modulus of elasticity at 150°C 366 712 490 250 - Storage modulus of elasticity at 300°C 6 200 11 180 - Tg (°C) of polyimide resins 260 260 250 >350 - Cleanliness ◎ ◎ ◎ ◎ -

[0087] As shown in Table 1, the cleaning sheet obtained in the examples exhibits excellent foreign matter removal performance and excellent results in both the adhesion test and the peel force test (180-degree peel adhesion force B of the cleaning layer to the mirror surface of the dummy wafer), indicating excellent transport performance. On the other hand, the comparative examples show poorer results in the adhesion test and the peel force test. [Industrial Applicability]

[0088] The cleaning sheet and the conveying component with cleaning function of the present invention are suitable for cleaning of substrate processing devices such as various manufacturing or inspection devices.

[0089] 10: Cleaning layer 20: Protective film 30: Adhesive layer 40: Support body 100: Cleaning tablets 200:Transporting components 300: Conveying components with cleaning function

Claims

1. A cleaning sheet comprising a cleaning layer, the cleaning layer comprising a polyimide resin containing structural units having an alicyclic backbone, the polyimide resin containing structural units derived from tetracarboxylic dianhydride having an alicyclic backbone, wherein the content ratio of the structural units having an alicyclic backbone is 5 to 50 parts by weight relative to 100 parts by weight of the polyimide resin, and the content ratio of the structural units derived from tetracarboxylic dianhydride having an alicyclic backbone is 5 to 40 parts by weight relative to 100 parts by weight of the polyimide resin, the cleaning layer having a storage modulus of elasticity of 100 MPa to 1000 MPa at 25°C.

2. The cleaning sheet of claim 1, wherein the polyimide resin further comprises structural units derived from a diamine having an alicyclic backbone.

3. The cleaning tablet of claim 1, wherein the alicyclic dianhydride having an alicyclic skeleton has 4 to 16 carbon atoms in its alicyclic skeleton.

4. The cleaning sheet as requested in item 1, wherein the glass transition temperature (Tg) of the aforementioned polyimide resin is 250°C to 300°C.

5. The cleaning sheet as claimed in claim 1 further includes a support disposed adjacent to the aforementioned cleaning layer.

6. A conveying member with a cleaning function, comprising a cleaning sheet as claimed in claim 1 and a conveying member.

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