Pericle

Abstract

The objective is to provide a pellicle which less likely generates outgas.　A pellicle (10) of the present disclosure comprises a pellicle frame (14), a pellicle film (12) supported on one end face of the pellicle frame (14), and an adhesive layer (15) provided on the other end face of the pellicle frame (14). A degree of swelling of the adhesive layer (15) expressed in the following formula (A) is not more than 200%.　Formula A: [(Mass after immersion of a 10 mg test piece collected from the adhesive layer) / 10 mg] × 100 In formula (A), the mass after immersion denotes the mass of the test piece after immersing the test piece for 6 hours in 10 ml of decane solution with a capillary column GC concentration of at least 99.0%.

Description

[Technical field]

[0001] The present disclosure relates to pellicles. [Background technology]

[0002] As the performance of the semiconductor exposure process improves, the pattern width of semiconductor integrated circuits is becoming finer. In the exposure process, if foreign matter such as dust adheres to a photomask, exposure failure may occur, which may result in a drop in the yield of semiconductor integrated circuits. A pellicle, which is a photomask cover, is attached to the photomask to prevent foreign matter such as dust from adhering to the surface of the photomask.

[0003] In recent years, as exposure patterns have become increasingly finer, DUV (Deep UV) has become the preferred light source for exposure. Instead of ultra violet (far ultraviolet) light, the use of EUV (extreme ultra violet) light, which has a shorter wavelength, is becoming more widespread. As the wavelength of the exposure light becomes shorter, the frequency of contamination of the pellicle film or photomask due to exposure (hereinafter referred to as "haze") is increasing. The cause of such haze is thought to be organic gas components (hereinafter referred to as "outgassing") generated from the adhesive during exposure.

[0004] Patent Document 1 discloses a pellicle that effectively prevents the occurrence of haze on a photomask. The pellicle disclosed in Patent Document 1 has a pellicle frame, a pellicle film formed on one end surface of the pellicle frame, and an adhesive formed on the other end surface of the pellicle frame. The adhesive is made of a specified adhesive composition. The total mass of the polymerization initiator in the adhesive is 8 ppm or less with respect to the total weight of the adhesive.

[0005] Patent Document 2 discloses a pellicle that prevents the adsorption of organic gas to a photomask, which causes haze, by imparting the organic gas adsorption performance to the adhesive itself used for the pellicle. The pellicle disclosed in Patent Document 2 has a pellicle frame and a pellicle film formed on one end face of the pellicle frame, and an adhesive formed on the other end face of the pellicle frame. The weight swelling degree of the adhesive by toluene is 5 times or more. The "weight swelling degree" indicates the rate of increase when an elastic gel (adhesive) absorbs a liquid (solvent) and its weight increases.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0007] As requirements for a pellicle, it is required to prevent foreign substances from adhering to the photomask and to efficiently transmit exposure light through the pellicle film. In particular, with the recent progress in miniaturization, there is a need to reduce the amount of outgas generated during exposure. In addition, even when the pellicle is used for a longer period of time, there is a need to suppress the occurrence of adhesion of a carbon film due to outgas (hereinafter referred to as "contamination") in the pellicle film and the exposure apparatus. That is, a pellicle that is less likely to generate outgas is required.

[0008] This disclosure is made in view of the above circumstances. The problem to be solved by one embodiment of this disclosure is to provide a pellicle that is less likely to generate outgas.

Means for Solving the Problems

[0009] Means for solving the above problems include the following embodiments. <1> A pellicle frame, A pellicle film supported on one end face of the pellicle frame, And an adhesive layer provided on the other end face of the pellicle frame Comprising, A pellicle in which the swelling degree represented by the following formula (A) of the adhesive layer is 200% or less. Formula (A): [(Mass after immersion of a 10 mg test piece collected from the adhesive layer) / 10 mg] × 100 (In the above formula (A), the mass after immersion indicates the mass of the test piece after immersing the test piece in 10 ml of a decane solution with a capillary column GC concentration of 99. 0% % or more for 6 hours.) <2> The pellicle according to <1>, wherein the glass transition temperature Tg of the adhesive layer is -25°C to 10°C. <3> The pellicle according to <1> or <2>, wherein the adhesive layer contains a copolymer of a (meth)acrylic acid alkyl ester monomer and a monomer having a functional group reactive with at least one of an isocyanate group, an epoxy group, and an acid anhydride. <4> The pellicle according to <3>, wherein the (meth)acrylic acid alkyl ester monomer has at least one of an alkyl group having 1 to 3 carbon atoms and an alicyclic alkyl group. <5> The pellicle according to <3> or <4>, wherein the content of the (meth)acrylic acid alkyl ester monomer is 80 parts by mass to 99.5 parts by mass with respect to 100 parts by mass of the total amount of monomers constituting the copolymer. <6> The pellicle according to any one of <3> to <5>, wherein the content of the monomer having the functional group is 0.5 parts by mass to 20 parts by mass with respect to 100 parts by mass of the total amount of monomers constituting the copolymer. <7> The pellicle according to any one of <3> to <6>, wherein the adhesive layer contains a reaction product of the copolymer and a crosslinking agent, and the content of the crosslinking agent is 0.002 parts by mass to 3.000 parts by mass with respect to 100 parts by mass of the total amount of monomers constituting the copolymer. The outgas generation amount obtained by converting the gas amount when the following (a) to (d) are executed in this order into n-decane is 1.5 μg or less, and the pellicle according to any one of <1> to <7>. (a) Heating the pellicle under the conditions of 120° C. and for 20 hours (b) Sealing the pellicle in a resin bag and storing it for 2 weeks in an atmosphere of 25° C. (c) Heating the pellicle under the conditions of 50° C. and for 4 hours and absorbing the gas released by an adsorbent (d) Heating the adsorbent for 10 minutes and measuring the gas amount

Advantages of the Invention

[0010] According to the present disclosure, a pellicle in which outgas is less likely to be generated is provided.

Brief Description of the Drawings

[0011]

Figure 1

Modes for Carrying Out the Invention

[0012] In the present disclosure, a numerical range indicated using “to” means a range including the numerical values described before and after “to” as the minimum value and the maximum value, respectively. In the numerical ranges described stepwise in the present disclosure, the upper limit value or the lower limit value described in a certain numerical range may be replaced with the upper limit value or the lower limit value of the numerical range of other stepwise descriptions. In the numerical ranges described in the present disclosure, the upper limit value or the lower limit value described in a certain numerical range may be replaced with the value shown in the examples. In the present disclosure, a combination of two or more preferred modes is a more preferred mode. In the present disclosure, the amount of each component means the total amount of a plurality of substances when there are a plurality of substances corresponding to each component, unless otherwise specified. In the present disclosure, the term "process" includes not only an independent process but also a process that cannot be clearly distinguished from other processes as long as the intended purpose of the process is achieved. In the present disclosure, when the expression "(meth)acrylic" is used, it means one or both of "acrylic" and "methacrylic".

[0013] (1) Embodiment The pellicle according to an embodiment of the present disclosure includes a pellicle frame, a pellicle film, and an adhesive layer. The pellicle film is supported on one end face of the pellicle frame. The adhesive layer is provided on the other end face of the pellicle frame. In the pellicle according to the embodiment, the swelling degree (hereinafter simply referred to as "swelling degree") represented by the following formula (A) of the adhesive layer is 200% or less.

[0014] Formula (A): [(Mass after immersion of a 10 mg test piece taken from the adhesive layer) / 10 mg]×100 In the formula (A), the mass after immersion indicates the mass of the test piece after immersing the test piece in 10 ml of a decane solution having a capillary column GC (gas chromatograph) concentration of 99. 0% The above for 6 hours.

[0015] In the present disclosure, the "swelling degree" indicates the mass change rate (%) of the test piece when the test piece is immersed in 10 ml of a decane solution having a capillary column GC concentration of 99.0% or more for 6 hours. In the present disclosure, the "decane solution having a capillary column GC concentration of 99.0% or more" indicates a decane solution in which the purity of decane measured by a capillary column GC is 99.0% or more. The "purity of decane" indicates the ratio of the peak area of decane to the total peak area of the gas chromatogram obtained by measuring the decane solution with a capillary column GC.

[0016] Since the pellicle according to the embodiment has the above configuration, outgassing is less likely to occur. This is presumably mainly due to the following reasons. The pellicle is usually shipped in a state sealed in a resin bag by heat sealing or the like (hereinafter referred to as the "packaged state") so that foreign matters such as dust do not adhere to the pellicle. The material of the resin bag is usually manufactured by decomposing naphtha. As a result, the resin bag emits hydrocarbon-based gases (hereinafter referred to as "hydrocarbon-based gases") derived from the material of the resin bag. Therefore, the adhesive layer of the conventional pellicle may easily adsorb hydrocarbon-based gases in the packaged state. EUV light with a short wavelength is easily absorbed by any substance. Therefore, exposure using EUV light is performed in a vacuum atmosphere. Further, in exposure using EUV light, the adhesive layer of the pellicle is expected to be exposed to a high temperature (for example, 50°C to 60°C). As a result, the hydrocarbon-based substances adsorbed on the conventional adhesive layer are likely to be released from the adhesive layer particularly during exposure using EUV light, and may constitute a part of outgassing. On the other hand, in the embodiment, "the swelling degree represented by the following formula (A) of the adhesive layer is 200% or less" indicates that the adhesive layer is less likely to absorb hydrocarbon-based gases than the conventional adhesive. In other words, in the embodiment, in the packaged state, the adhesive layer is less likely to absorb hydrocarbon-based gases derived from the material of the resin bag. Therefore, in the embodiment, during exposure using EUV light, the amount of outgassing generated from the hydrocarbon-based gases adsorbed on the adhesive layer is less than that of the conventional pellicle. As a result, it is presumed that the pellicle according to the embodiment is less likely to generate hydrocarbon-based gases than the conventional pellicle.

[0017] In addition, the pellicle according to the embodiment is less likely to absorb hydrocarbon-based gases than the conventional pellicle even when stored for a long time in the packaged state. As a result, the pellicle according to the embodiment can be made less likely to generate outgassing than the conventional pellicle even when stored for a long time in the packaged state. For example, in the embodiment, after the pellicle is manufactured and before it is put into a packaged state, the adhesive layer is less likely to adsorb the gas in the atmosphere (e.g., the air in the factory) to which the pellicle is exposed than the conventional adhesive layer. Further, in the embodiment, even after the pellicle is attached to the photomask in the vacuum chamber, the adhesive layer is less likely to adsorb the gas in the vacuum chamber than the conventional adhesive layer. Therefore, in the embodiment, during the exposure using EUV light, the amount of outgas generated from the gas adsorbed on the adhesive layer is less than that of the conventional pellicle. As a result, the pellicle according to the embodiment can be less likely to generate outgas than the conventional pellicle. In the embodiment, it is possible to less likely generate haze on the pellicle film due to the excitation of gas by exposure to EUV light or ArF light.

[0018] (1.1) Swelling degree In the embodiment, the pellicle has a swelling degree of 200% or less. The upper limit of the swelling degree is 200% or less, and from the viewpoints such as further suppressing the amount of outgas generated from the degassed gas adsorbed by the adhesive layer, it is preferably 180% or less, more preferably 150% or less, and still more preferably 135% or less. The lower limit of the swelling degree is not particularly limited, and is preferably 10% or more, more preferably 50% or more, and still more preferably 110% or more. From these viewpoints, the swelling degree is preferably 10% to 200%, more preferably 10% to 180%, still more preferably 10% to 150%, particularly preferably 10% to 135%, even more preferably 50% to 135%, and still even more preferably 110% to 135%.

[0019] The method for measuring the swelling degree includes the following steps (A1) to (A7) and is executed in this order. (A1) Heat the entire pellicle under the conditions of 120 °C for 20 hours. (A2) Take out the pellicle from the inside of the heating device and leave it in the atmosphere at 25 °C to cool to room temperature. Cut a part of the adhesive layer contained in the pellicle to obtain a 10 mg test piece. Prepare a decane solution with a capillary column GC concentration of 99% or more. Immerse the test piece in 10 ml of the decane solution at room temperature for 6 hours. Take out the test piece from the decane solution, place it on a petri dish, and dry it for 3 minutes. (A7) Measure the mass of the test piece, substitute the measured value of the test piece into formula (A), and calculate the swelling degree. Details of the method for measuring the swelling degree will be described later in the examples.

[0020] Examples of methods for adjusting the swelling degree to 200% or less include, for example, a method of adjusting the glass transition temperature Tg of the adhesive layer to -25°C or higher. The glass transition temperature Tg of the adhesive layer will be described later.

[0021] (1.2) Outgassing amount In the embodiment, it is preferable that the outgassing amount obtained by converting the gas amount when the following (a) to (d) are performed in this order for the pellicle into n-decane is 1.5 μg or less. (a) Heating the pellicle under the conditions of 120°C and 20 hours (b) Sealing the pellicle in a resin bag and storing it for 2 weeks in an atmosphere of 25°C (c) Heating the pellicle under the conditions of 50°C and 4 hours and absorbing the released gas with an adsorbent (d) Heating the adsorbent for 10 minutes and measuring the gas amount Details of the method for measuring the outgassing amount will be described later in the examples.

[0022] The fact that the outgassing amount is 1.50 μg or less indicates that outgassing is less likely to occur. If the outgassing amount of the pellicle is within the above range, the pellicle can more effectively suppress the generation of haze during exposure.

[0023] The upper limit of the outgassing amount is more preferably 1.10 μg or less, still more preferably 0.50 μg or less, still more preferably 0.30 μ g or less, still more preferably 0.20 μg or less, still more preferably 0.10 g or less. The closer the outgassing amount is to 0 μg, the more preferable it is.

[0024] (1.3) Adhesive layer In an embodiment, the pellicle includes an adhesive layer. The adhesive layer enables the pellicle according to the embodiment to adhere to a photomask.

[0025] The adhesive layer is a gel-like viscoelastic body. The adhesive layer has viscosity and cohesive force. "Viscosity" refers to the property of a liquid that comes into contact with and wets the adherend, which is the photomask in this case. "Cohesive force" refers to the property of a solid that resists peeling from the photomask.

[0026] As will be described later, the adhesive layer is formed by processing such as applying, heating, drying, and curing a coating composition.

[0027] (1.3.1) Glass transition temperature The glass transition temperature Tg of the adhesive layer is preferably -25°C to 10°C. Thereby, the pellicle according to the embodiment can be less likely to generate outgas derived from the degassed gas adsorbed on the adhesive layer. Further, the adhesive layer has adhesive force in the use temperature range of the pellicle (for example, 20°C or higher), and the pellicle is less likely to peel from the photomask even when exposed to a high-temperature environment. The lower limit of the glass transition temperature Tg of the adhesive layer is preferably -25°C or higher, more preferably -20°C or higher, still more preferably -15°C or higher, and most preferably -10°C or higher from the viewpoint of making it less likely to generate outgas. The upper limit of the glass transition temperature Tg of the adhesive layer is preferably 10°C or lower, more preferably 5°C or lower, still more preferably 0°C or lower from the viewpoint of imparting appropriate adhesiveness at room temperature. From the viewpoint of facilitating the suppression of the distortion of the original plate due to the distortion of the pellicle frame, the upper limit of the glass transition temperature Tg of the adhesive layer is preferably -5°C or lower, more preferably -10°C or lower. From these viewpoints, the glass transition temperature Tg is preferably -25°C to 5°C, more preferably -25°C to 0°C, more preferably -25°C to -5°C, more preferably -25°C to -10°C, still more preferably -22°C to -10°C, particularly preferably -20°C to -10°C, and even more preferably -18°C to -10°C. The measurement of the glass transition temperature Tg of the adhesive layer is the same as the method described in the examples.

[0028] (1.3.2) Coating composition The coating composition contains compounds selected from various polymers, solvents, crosslinking agents, catalysts, initiators, etc., depending on the adhesive layer to be formed. The coating composition is a precursor of the pressure-sensitive adhesive composition. That is, when the coating composition cures, it becomes a pressure-sensitive adhesive composition.

[0029] (1.3.3) Pressure-sensitive adhesive composition The pressure-sensitive adhesive composition is not particularly limited, and examples include acrylic-based, silicone-based, styrene-butadiene-based, urethane-based, and olefin-based pressure-sensitive adhesives. Among them, from the viewpoint of reducing the outgassing amount generated from the pellicle, etc., the pressure-sensitive adhesive composition preferably contains an acrylic-based pressure-sensitive adhesive.

[0030] Hereinafter, the acrylic-based pressure-sensitive adhesive will be described.

[0031] (1.3.4) Acrylic-based pressure-sensitive adhesive The acrylic-based pressure-sensitive adhesive preferably contains a (meth)acrylic acid alkyl ester copolymer.

[0032] (1.3.4.1) (Meth)acrylic acid alkyl ester copolymer The (meth)acrylic acid alkyl ester copolymer a (meth)acrylic acid alkyl ester monomer, and It is preferable to include a copolymer with a monomer having a functional group reactive with at least one of an isocyanate group, an epoxy group, and an acid anhydride (hereinafter also referred to as a "functional group-containing monomer").

[0033] Hereinafter, the copolymer of an alkyl (meth)acrylate monomer and a functional group-containing monomer is also referred to as "the copolymer".

[0034] Since the acrylic pressure-sensitive adhesive contains an alkyl (meth)acrylate copolymer, the pellicle is difficult to peel from the photomask even when exposed to a high-temperature environment (for example, 50°C to 60°C), and the occurrence of adhesive residue can be suppressed. "Adhesive residue" means that at least a part of the adhesive layer remains on the photomask after the pellicle is peeled from the photomask.

[0035] The weight-average molecular weight (Mw) of the alkyl (meth)acrylate copolymer is preferably 30,000 to 2,500,000, more preferably 50,000 to 1,500,000, and still more preferably 70,000 to 1,200,000. If the weight-average molecular weight (Mw) of the alkyl (meth)acrylate copolymer is within the above range, the pellicle is more difficult to peel from the photomask even when exposed to a high-temperature environment (for example, 50°C to 60°C), and the occurrence of adhesive residue can be further suppressed. If the upper limit of the weight-average molecular weight (Mw) of the alkyl (meth)acrylate copolymer is 2,500,000 or less, the solution viscosity can be controlled within a range easy to process even when the solid content concentration of the coating composition is increased. The upper limit of the weight-average molecular weight (Mw) of the alkyl (meth)acrylate copolymer is preferably 2,500,000 or less, more preferably 1,500,000 or less, still more preferably 1,200,000 or less, even more preferably 135,000 or less, still even more preferably 126,000 or less, and yet even more preferably 112,000 or less. If the lower limit of the weight average molecular weight (Mw) of the (meth)acrylic acid alkyl ester copolymer is 30,000 or more, the pellicle is less likely to peel off from the photomask even when exposed to a high-temperature environment (for example, 50°C to 60°C), and the occurrence of adhesive residue can be suppressed. The lower limit of the weight average molecular weight (Mw) of the (meth)acrylic acid alkyl ester copolymer is preferably 30,000 or more, more preferably 50,000 or more, and even more preferably 70,000 or more. The measurement method of the weight average molecular weight (Mw) of the (meth)acrylic acid alkyl ester copolymer is GPC (gel permeation chromatography), and the details of the measurement method will be described later in the examples. For example, generally, the higher the monomer concentration during the polymerization reaction, the greater the tendency for the weight average molecular weight (Mw) to increase. The lower the amount of the polymerization initiator and the lower the polymerization temperature, the greater the tendency for the weight average molecular weight (Mw) to increase. The weight average molecular weight can be control controlled by adjusting the monomer concentration, the amount of the polymerization initiator, and the polymerization temperature.

[0036] The number average molecular weight (Mn) of the (meth)acrylic acid alkyl ester copolymer is preferably 5,000 to 500,000, more preferably 8,000 to 300,000, even more preferably 10,000 to 200,000, particularly preferably 20,000 to 200,000, and still more preferably 30,800 to 36,000. If the upper limit of the number average molecular weight (Mn) of the (meth)acrylic acid alkyl ester copolymer is 500,000 or less, even if the solid content concentration of the coating composition is increased, the solution viscosity can be controlled within a range that is easy to process. The upper limit of the number average molecular weight (Mn) of the (meth)acrylic acid alkyl ester copolymer is preferably 500,000 or less, more preferably 300,000 or less, and even more preferably 200,000 or less. If the lower limit of the number average molecular weight (Mn) of the (meth)acrylic acid alkyl ester copolymer is 5,000 or more, it is more difficult to peel off from the photomask even when exposed to a high temperature environment (for example, 50°C to 60°C), and the occurrence of glue residue can be suppressed. The lower limit of the number average molecular weight (Mn) of the (meth)acrylic acid alkyl ester copolymer is preferably 5,000 or more, more preferably 8,000 or more, still more preferably 10,000 or more, and most preferably 20,000 or more. The measurement method of the number average molecular weight (Mn) of the (meth)acrylic acid alkyl ester copolymer is GPC (gel permeation chromatography), and the details of the measurement method will be described later in the examples.

[0037] The "weight average molecular weight (Mw) / number average molecular weight (Mn)" (hereinafter also referred to as "Mw / Mn") of the (meth)acrylic acid alkyl ester copolymer is preferably 1.0 to 10.0, more preferably 2.0 to 9.0, still more preferably 2.5 to 8.0, particularly preferably 3.0 to 7.0, and even more preferably 3.3 to 3.7. If the upper limit of Mw / Mn is 10.0 or less, the occurrence of glue residue can be suppressed. The upper limit of Mw / Mn is preferably 10.0 or less, more preferably 9.0 or less, still more preferably 8.0 or less, and most preferably 7.0 or less. If the lower limit of Mw / Mn is 1.0 or more, the (meth)acrylic acid alkyl ester copolymer can be easily produced. The lower limit of Mw / Mn is preferably 1.0 or more, more preferably 2.0 or more, still more preferably 2.5 or more, and most preferably 3.0 or more.

[0038] The (meth)acrylic acid alkyl ester monomer preferably includes a (meth)acrylic acid alkyl ester monomer having an alkyl group with 1 to 14 carbon atoms. Examples of the (meth)acrylic acid alkyl ester monomer having an alkyl group with 1 to 14 carbon atoms include (meth)acrylic acid ester monomers of linear aliphatic alcohols, (meth)acrylic acid ester monomers of branched aliphatic alcohols, and (meth)acrylic acid ester monomers of cyclic aliphatic alcohols. Examples of the (meth)acrylic acid ester monomer of a linear aliphatic alcohol include methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, propyl (meth)acrylate, hexyl (meth)acrylate, octyl (meth)acrylate, decyl (meth)acrylate, dodecyl (meth)acrylate, lauryl (meth)acrylate, and the like. Examples of the (meth)acrylic acid ester monomer of a branched-chain aliphatic alcohol include isobutyl (meth)acrylate, isoamyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isooctyl (meth)acrylate, isononyl (meth)acrylate, and the like. Examples of the (meth)acrylic acid ester monomer of a cyclic aliphatic alcohol include cyclohexyl (meth)acrylate, dicyclopentenyl oxyethyl (meth)acrylate, and the like. These may be used alone or in combination of two or more.

[0039] Among these, the (meth)acrylic acid alkyl ester monomer preferably has at least one of an alkyl group having 1 to 3 carbon atoms and an alicyclic alkyl group. Hereinafter, the (meth)acrylic acid alkyl ester monomer having at least one of an alkyl group having 1 to 3 carbon atoms and an alicyclic alkyl group is referred to as a "high Tg monomer". "Tg" means the glass transition temperature. In order to further reduce the outgas generation amount, the (meth)acrylic acid alkyl ester monomer is more preferably a (meth)acrylic acid alkyl ester monomer having an alkyl group having 1 to 3 carbon atoms or an alicyclic alkyl group, and even more preferably a (meth)acrylic acid alkyl ester monomer having an alkyl group having 1 to 3 carbon atoms. When the (meth)acrylic acid alkyl ester monomer is a (meth)acrylic acid alkyl ester monomer having an alicyclic alkyl group, from the viewpoint of availability, the carbon number of the alicyclic alkyl group is preferably 5 to 10. When the (meth)acrylic acid alkyl ester monomer contains a high-Tg monomer, the pellicle is difficult to peel off from the photomask even when exposed to a high-temperature atmosphere. Specifically, examples of the high-Tg monomer include methyl acrylate, ethyl acrylate, propyl acrylate, isopropyl acrylate, cyclohexyl acrylate, dicyclopentanyl acrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, isopropyl methacrylate, cyclohexyl methacrylate, dicyclopentanyl methacrylate, and the like. Among these, in order to further reduce the amount of outgas generated, the (meth)acrylic acid alkyl ester monomer preferably has at least one of an alkyl group having 1 to 2 carbon atoms and an alicyclic alkyl group, and more preferably, the (meth)acrylic acid alkyl ester monomer has an alkyl group having 1 to 2 carbon atoms.

[0040] The content of the (meth)acrylic acid alkyl ester monomer is preferably 80 parts by mass to 99.5 parts by mass, more preferably 85 parts by mass to 99.5 parts by mass, and still more preferably 87 parts by mass to 99.5 parts by mass, based on 100 parts by mass of the total amount of the monomers constituting the copolymer. When the content of the (meth)acrylic acid alkyl ester monomer is within the range of 80 parts by mass to 99.5 parts by mass, an appropriate adhesive force can be achieved. From the viewpoint of further reducing the amount of outgas generated, the content of the (meth)acrylic acid alkyl ester monomer, which is at least one of an alkyl group having 1 to 3 carbon atoms and an alicyclic alkyl group, is preferably within the range of 80 parts by mass to 99.5 parts by mass. From the same viewpoint, the content of the (meth)acrylic acid alkyl ester monomer, which is at least one of an alkyl group having 1 to 2 carbon atoms and an alicyclic alkyl group, is more preferably within the range of 80 parts by mass to 99.5 parts by mass. From the same viewpoint, the content of the (meth)acrylic acid alkyl ester monomer having an alkyl group having 1 to 2 carbon atoms is more preferably within the range of 80 parts by mass to 99.5 parts by mass.

[0041] The functional group-containing monomer is a monomer copolymerizable with an alkyl (meth)acrylate monomer. The functional group-containing monomer has a functional group having reactivity with at least one of an isocyanate group, an epoxy group, and an acid anhydride. Examples of the functional group-containing monomer include a carboxy group-containing monomer, a hydroxy group-containing monomer, an epoxy group-containing monomer, and the like. Examples of the carboxy group-containing monomer include (meth)acrylic acid, itaconic acid, itaconic acid (meth)acrylate, maleic acid, crotonic acid, and the like. Examples of the hydroxy group-containing monomer include 2-hydroxyethyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, and the like. Examples of the epoxy group-containing monomer include glycidyl (meth)acrylate and the like. These may be used alone or in combination of two or more. In particular, from the viewpoints of copolymerizability, versatility, etc., the functional group-containing monomer preferably includes a hydroxy group-containing (meth)acrylic acid having a hydroxyalkyl group having 2 to 4 carbon atoms, or glycidyl (meth)acrylate which is an epoxy group-containing monomer. Examples of the hydroxy group-containing (meth)acrylic acid having a hydroxyalkyl group having 2 to 4 carbon atoms include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, and the like.

[0042] The content of the functional group-containing monomer is preferably, for example, 0.5 parts by mass to 20 parts by mass with respect to 100 parts by mass of the total amount of the monomers constituting the copolymer. From the viewpoint of improving the adhesive strength of the adhesive layer, the lower limit of the content of the functional group-containing monomer is more preferably 1 part by mass or more, still more preferably 2 parts by mass or more, and particularly preferably 3 parts by mass or more with respect to 100 parts by mass of the total amount of the monomers constituting the alkyl (meth)acrylate copolymer. From the viewpoint of making the adhesive strength of the adhesive layer an appropriate adhesive strength, the upper limit of the content of the functional group-containing monomer is more preferably 15 parts by mass or less, and even more preferably 10 parts by mass or less, based on 100 parts by mass of the total amount of the monomers constituting the (meth)acrylic acid alkyl ester copolymer.

[0043] (1.3.4.2) Polymerization method The polymerization method of the (meth)acrylic acid alkyl ester copolymer is not particularly limited, and examples thereof include solution polymerization, bulk polymerization, emulsion polymerization, various radical polymerizations, and the like. The (meth)acrylic acid alkyl ester copolymer obtained by these polymerization methods may be any of a random copolymer, a block copolymer, a graft copolymer, and the like.

[0044] (1.3.4.3) Polymerization solvent The reaction solution contains a polymerization solvent. In solution polymerization, for example, propyl acetate, ethyl acetate, toluene, etc. can be used as the polymerization solvent. Thereby, the viscosity of the copolymer solution can be adjusted. As a result, when polymerizing, the thickness and width of the coating composition are easily controlled. Examples of the diluting solvent include propyl acetate, acetone, ethyl acetate, toluene, and the like. The viscosity of the copolymer solution is preferably 1000 Pa·s or less, more preferably 500 Pa·s or less, and even more preferably 200 Pa·s or less. The viscosity of the coating composition is the viscosity when the temperature of the coating composition is 25°C, and can be measured by a B-type viscometer.

[0045] (1.3.4.4) Solution polymerization As an example of solution polymerization, a method of adding a polymerization initiator to a mixed solution of monomers under an inert gas stream such as nitrogen and performing a polymerization reaction at 50°C to 100°C for 4 hours to 30 hours can be mentioned.

[0046] Examples of the polymerization initiator include azo polymerization initiators and peroxide polymerization initiators. Examples of the azo polymerization initiator include 2,2'-azobisisobutyronitrile (AIBN), 2 ,2'-azobis-2-methylbutyronitrile, dimethyl 2,2'-azobis(2-methylpropionate), 4,4'-azobis-4-cyanovaleric acid, and the like. Examples of the peroxide polymerization initiator include benzoyl peroxide and the like. The content of the polymerization initiator is preferably 0.01 parts by mass to 2.0 parts by mass with respect to 100 parts by mass of the total amount of all the monomers constituting the (meth)acrylic acid alkyl ester copolymer. In solution polymerization, in addition to the polymerization initiator, a chain transfer agent, an emulsifier, etc. may be added to the mixed solution of the monomers. As the chain transfer agent, emulsifier, etc., known ones can be appropriately selected and used.

[0047] The amount of the polymerization initiator remaining in the pressure-sensitive adhesive layer is preferably small. Thereby, the amount of outgas generated during exposure can be reduced. As a method for reducing the amount of the polymerization initiator remaining in the pressure-sensitive adhesive layer, a method of minimizing the addition amount of the polymerization initiator when polymerizing the (meth)acrylic acid alkyl ester copolymer, a method of using a polymerization initiator that is easily thermally decomposed, a method of heating the pressure-sensitive adhesive at a high temperature for a long time in the coating and drying process of the pressure-sensitive adhesive to decompose the polymerization initiator in the drying process, and the like can be mentioned.

[0048] The 10-hour half-life temperature is used as an index representing the thermal decomposition rate of the polymerization initiator. The "half-life" indicates the time until half of the polymerization initiator decomposes. The "10-hour half-life temperature" indicates the temperature at which the half-life is 10 hours. It is preferable to use a polymerization initiator having a low 10-hour half-life temperature as the polymerization initiator. The lower the 10-hour half-life temperature, the easier the polymerization initiator is thermally decomposed. As a result, it is difficult to remain in the pressure-sensitive adhesive layer. The 10-hour half-life temperature of the polymerization initiator is preferably 80 °C or lower, more preferably 75 °C or lower.

[0049] Examples of azo polymerization initiators with a low 10-hour half-life temperature include, for example, 2,2'-azobis( 4-methoxy-2,4-dimethylvaleronitrile) (10-hour half-life temperature: 30 °C), 2,2'-azobisisobutyronitrile (10-hour half-life temperature: 65 °C), 2,2-azobis (2,4-dimethylvaleronitrile) (10-hour half-life temperature: 51 °C), dimethyl 2,2'-azobis(2-methylpropionate) (10-hour half-life temperature: 66 °C), 2,2'-azobis(2-methylbutyronitrile) (10-hour half-life temperature: 67 °C), and the like. Examples of peroxide-based polymerization initiators with a low 10-hour half-life temperature include, for example, dibenzoyl peroxide (10-hour half-life temperature: 74 °C), dilauroyl peroxide (10-hour half-life temperature: 62 °C), and the like.

[0050] (1.3.4.5) Crosslinking agent The crosslinking agent is a compound whose functional groups contribute to the formation of a three-dimensional network structure by reacting with the copolymer. The acrylic pressure-sensitive adhesive preferably contains a reaction product of a (meth)acrylate copolymer and a crosslinking agent. Thereby, the cohesive force of the obtained adhesive layer can be improved, paste residue can be suppressed, and the adhesive force at high temperature can be improved. The crosslinking agent has at least one of an isocyanate group, an epoxy group, an acid anhydride, and a radical-generating group.

[0051] Examples of the crosslinking agent include monofunctional epoxy compounds, polyfunctional epoxy compounds, acid anhydride-based compounds, metal salts, metal alkoxides, aldehyde-based compounds, non-amino resin-based amino compounds, urea-based compounds, isocyanate-based compounds, metal chelate-based compounds, melamine-based compounds, aziridine-based compounds, azo initiators, organic peroxides, and the like. Among them, in terms of excellent reactivity with the functional group components of the (meth)acrylic acid alkyl ester copolymer, it is more preferable that the crosslinking agent is at least one of a monofunctional epoxy compound, a polyfunctional epoxy compound, an isocyanate-based compound, and an acid anhydride-based compound, and it is more preferable that it is an acid anhydride-based compound.

[0052] Examples of the monofunctional epoxy compound include glycidyl (meth)acrylate, glycidyl acetate, butyl glycidyl ether, phenyl glycidyl ether, and the like. Examples of the polyfunctional epoxy compound include neopentyl glycol diglycidyl ether, polyethylene glycol diglycidyl ether, bisphenol A diglycidyl ether, bisphenol F diglycidyl ether, phthalic acid diglycidyl ester, dimer acid diglycidyl ester, triglycidyl isocyanurate, diglycerol triglycidyl ether, sorbitol tetraglycidyl ether, N, N, N', N'-tetraglycidyl m-xylenediamine, 1,3-bis(N, N-diglycidylaminomethyl)cyclohexane, N, N, N', N'-tetraglycidyl diaminodiphenylmethane, and the like. Examples of the acid anhydride-based compound include aliphatic dicarboxylic acid anhydride, aromatic polyvalent carboxylic acid anhydride, and the like. Examples of the aliphatic dicarboxylic acid anhydride include maleic anhydride, hexahydrophthalic anhydride, hexahydro-4-methylphthalic anhydride, bicyclo[2.2.1]heptane-2,3-dicar boxylic anhydride, 2-methylbicyclo[2.2.1]heptane-2,3-dicarboxylic anhydride, tetrahydrophthalic anhydride, and the like. Examples of the aromatic polyvalent carboxylic acid anhydride include phthalic anhydride, trimellitic anhydride, and the like. Examples of the isocyanate-based compound include xylylene diisocyanate, hexamethylene diisocyanate, tolylene diisocyanate, their multimers, derivatives, polymers, and the like. These may be used alone or in combination of two or more.

[0053] The crosslinking agent may be a product. Examples of the crosslinking agent product include "RICACID MH-700G" manufactured by Shin Nippon Rika Kogyo Co., Ltd.

[0054] The adhesive layer contains a reaction product of the copolymer and the crosslinking agent, and the content of the crosslinking agent is preferably 0.002 parts by mass to 3.000 parts by mass with respect to 100 parts by mass of the total amount of the monomers constituting the copolymer. The content of the crosslinking agent is preferably 0.002 parts by mass to 3.000 parts by mass with respect to 100 parts by mass of the total amount of the monomers constituting the copolymer, and the adhesive is less likely to cause adhesive residue and the stress on the flatness of the original plate is relaxed. layer From the viewpoints of obtaining etc., it is more preferably 0.002 parts by mass to 2.00 parts by mass, still more preferably 0.005 parts by mass to 2.000 parts by mass, still more preferably 0.010 parts by mass to 1.000 parts by mass, and particularly preferably 0.100 parts by mass to 0.500 parts by mass. If the upper limit of the content of the crosslinking agent is 3.000 parts by mass or less, the crosslinking density of the (meth)acrylic acid alkyl ester copolymer does not become too large. Therefore, it is considered that the adhesive absorbs the stress applied to the photomask, and the influence of the adhesive layer on the flatness of the photomask is relaxed. The upper limit of the content of the crosslinking agent is preferably 2.000 parts by mass or less, more preferably 1.000 parts by mass or less. On the other hand, if the lower limit of the content of the crosslinking agent is 0.002 parts by mass or more, the crosslinking density does not become too small, so the handleability during the manufacturing process is maintained, and it is considered that adhesive residue is less likely to occur when peeling the pellicle from the photomask. If the content of the crosslinking agent is within the range of 0.002 parts by mass to 3.000 parts by mass, a pellicle with suppressed occurrence of adhesive residue can be obtained.

[0055] (1.3.4.6) Catalyst The coating composition may further contain a catalyst. Thereby, the curing of the (meth)acrylic acid alkyl ester copolymer can be further promoted. Examples of the catalyst include amine-based catalysts and the like. Examples of the amine-based catalyst include octylate of (1, 8-diazabicyclo-(5.4.0)undecene-7), triethylenediamine, and the like. The amine-based catalyst may be a product of San-Apro Ltd. such as "DBU", "DBN", "U-CAT", "U-CAT SA1", "U-CAT SA102", and the like. The content of the catalyst is preferably 0.01 part by mass to 3.00 parts by mass, more preferably 0.10 part by mass to 1.00 part by mass, based on 100 parts by mass of the (meth)acrylic acid alkyl ester copolymer.

[0056] (1.3.4.7) Surface modifier The coating composition preferably does not contain a surface modifier. Thereby, the amount of outgas generated can be suppressed.

[0057] (1.3.4.8) Additive The coating composition may contain additives such as a filler, a pigment, a diluent, an antioxidant, and a tackifier, if necessary. These additives may be used alone or in combination of two or more.

[0058] (1.3.4.9) Dilution solvent The coating composition may contain a dilution solvent. Thereby, the viscosity of the coating composition can be adjusted. As a result, when the coating composition is applied to the other end face of the pellicle frame, the thickness and width of the coating composition are easily controlled. Examples of the dilution solvent include propyl acetate, acetone, ethyl acetate, toluene, and the like. The viscosity of the coating composition is preferably 50 Pa·s or less, more preferably 10 Pa·s to 40 Pa·s, and still more preferably 20 Pa·s to 30 Pa·s. The viscosity of the coating composition is the viscosity when the temperature of the coating composition is 25°C and can be measured by an E-type viscometer.

[0059] (1.3.5) Properties of the adhesive layer, etc. From the viewpoints of suppressing deterioration of the adhesive layer, suppressing the outgassing amount, etc., the adhesive layer is preferably water-insoluble. Deterioration of the adhesive layer includes deterioration of the adhesive layer such as deterioration of the adhesive force and deterioration of the mask distortion due to exposure to moisture in the atmosphere. When moisture in the atmospheric atmosphere adsorbs to the adhesive layer, outgassing due to the moisture adsorbed to the adhesive layer is likely to occur in a vacuum environment such as EUV exposure. The fact that the adhesive layer is water-insoluble indicates that moisture in the atmospheric atmosphere hardly adsorbs to the adhesive layer. Therefore, a water-insoluble adhesive layer can suppress the outgassing amount. From the same viewpoint, the raw material of the adhesive layer preferably includes the copolymer and the copolymer is water-insoluble. to It includes deterioration of the adhesive layer such as deterioration of the adhesive force and deterioration of the mask distortion due to exposure to moisture in the atmosphere. When moisture in the atmospheric atmosphere adsorbs to the adhesive layer, outgassing due to the moisture adsorbed to the adhesive layer is likely to occur in a vacuum environment such as EUV exposure. The fact that the adhesive layer is water-insoluble indicates that moisture in the atmospheric atmosphere hardly adsorbs to the adhesive layer. Therefore, a water-insoluble adhesive layer can suppress the outgassing amount. From the same viewpoint, the raw material of the adhesive layer preferably includes the copolymer and the copolymer is water-insoluble.

[0060] Whether the adhesive layer is water-insoluble or not may be evaluated using the first gel fraction. The first gel fraction indicates the ratio (mass%) of the mass of the adhesive layer after the first treatment to the mass of the adhesive layer before the first treatment. The first treatment refers to a treatment in which the adhesive layer is immersed in water, heated and stirred at 60 °C for 3 hours to obtain a residue of the adhesive layer that does not dissolve in water, and the obtained residue is dried at 100 °C for 3 hours. In the first treatment, the amount of water used is 100 parts by mass with respect to 1 part by mass of the adhesive layer. The mass of the adhesive layer after the first treatment indicates the remaining mass of the adhesive layer after drying. The adhesive layer used for the evaluation may be a test piece collected from the adhesive layer. slag The remaining mass after drying is shown. The adhesive layer used for the evaluation may be a test piece collected from the adhesive layer. If the first gel fraction is 70 mass% or less, it may be determined that the adhesive layer is water-soluble. If the first gel fraction is 80 mass% or less, it may be determined that the adhesive layer is water-soluble. If the first gel fraction is 90 mass% or less, it may be determined that the adhesive layer is water-soluble.

[0061] Whether the copolymer is water-insoluble may be evaluated using the second gel fraction. The second gel fraction indicates the ratio (mass %) of the mass of the copolymer after the second treatment to the mass of the copolymer before the second treatment. The second treatment refers to a process of immersing the copolymer in water, heating and stirring at 60°C for 3 hours to obtain a residue of the copolymer that does not dissolve in water, and drying the obtained residue at 100°C for 3 hours. In the second treatment, the amount of water used is 100 parts by mass with respect to 1 part by mass of the copolymer. The mass of the copolymer after the second treatment indicates the mass after drying of the residue of the copolymer. The copolymer used for the evaluation may be a test piece sampled from the copolymer. slag The mass after drying of the residue is indicated. The copolymer used for the evaluation may be a test piece sampled from the copolymer. If the second gel fraction is 70% by mass or less, it may be determined that the copolymer is water-soluble. If the second gel fraction is 80% by mass or less, it may be determined that the copolymer is water-soluble. If the second gel fraction is 90% by mass or less, it may be determined that the copolymer is water-soluble.

[0062] From the viewpoints of suppressing deterioration of the adhesive layer, suppressing the amount of outgas, etc., the adhesive layer may contain metal ions and ammonium ions. Examples of the metal ions include sodium ions, potassium ions, calcium ions, etc. The content ratio of the total amount of metal ions and ammonium ions is preferably 4% by mass or less, more preferably 3% by mass or less, still more preferably 2% by mass or less, particularly preferably 1% or less, and even more preferably 0.5% by mass or less with respect to the total amount of the adhesive layer. The content ratio of the total amount of metal ions and ammonium ions is preferably 4% by mass or less, more preferably 3% by mass or less, still more preferably 2% by mass or less, particularly preferably 1% by mass or less, and even more preferably 0.5% by mass or less with respect to the total amount of the monomers constituting the copolymer. In order to suppress contamination of the device by components derived from ions such as metal ions, the content ratio of the total amount of metal ions and ammonium ions is preferably 4% by mass or less, more preferably 3% by mass or less, still more preferably 2% by mass or less, particularly preferably 1% by mass or less, and even more preferably 0.5% by mass or less with respect to the total amount of the adhesive layer. In order to suppress contamination of the device by components derived from ions such as metal ions, the content ratio of the total amount of metal ions and ammonium ions is preferably 4% by mass or less, more preferably 3% by mass or less, still more preferably 2% by mass or less, particularly preferably 1% by mass or less, and even more preferably 0.5% by mass or less with respect to the total amount of the monomers constituting the copolymer.

[0063] (1.3.6) Thickness The thickness of the adhesive layer is not particularly limited, and is preferably 0.01 mm to 1 mm, more preferably 0.1 mm to 0.8 mm. If the thickness of the adhesive layer is within the above range, it is possible to reduce the distortion of the photomask after attachment and eliminate errors during exposure while ensuring the adhesiveness to the photomask.

[0064] (1.4) Pericle Frame In an embodiment, the pericle includes a pericle frame. The pericle frame supports the pericle film.

[0065] The pericle frame is a cylindrical object. The pericle frame has a through hole. The through hole indicates a space through which the exposure that has passed through the pericle film reaches the photomask. The pericle frame may have a ventilation hole. The ventilation hole communicates the internal space of the pericle and the external space of the pericle when the pericle frame is attached to the photomask. The "internal space of the pericle" refers to the space surrounded by the pericle and the photomask. The "external space of the pericle" refers to the space not surrounded by the pericle and the photomask.

[0066] The rectangular pericle frame is composed of four sides when viewed from the thickness direction. The length of one side in the longitudinal direction is preferably 200 mm or less. The size of the pellicle frame and the like are standardized according to the type of exposure apparatus. The fact that the length of one side in the longitudinal direction of the pellicle frame is 200 mm or less satisfies the size standardized for exposure using EUV light. The length of one side in the short transverse direction can be, for example, 5 mm to 180 mm, preferably 80 mm to 170 mm, more preferably 100 mm to 160 mm. The height of the pellicle frame (i.e., the length of the pellicle frame in the thickness direction) is not particularly limited, and is preferably 3.0 mm or less, more preferably 2.4 mm or less, still more preferably 2.375 mm or less. Thereby, the pellicle frame satisfies the size standardized for EUV exposure. The height of the pellicle frame standardized for EUV exposure is, for example, 2.375 mm. The mass of the pellicle frame is not particularly limited, and is preferably 20 g or less, more preferably 15 g or less. Thereby, the pellicle frame is suitable for use in EUV exposure.

[0067] Examples of the material of the pellicle frame include aluminum, titanium, stainless steel, ceramic-based materials (such as silicon, glass, etc.), resins such as polyethylene, and the like. The shape of the pellicle frame corresponds to the shape of the photomask. Examples of the shape of the pellicle frame include a rectangular frame shape, a square frame shape, and the like.

[0068] (1.5) Pellicle film In an embodiment, the pellicle includes a pellicle film. The pellicle film prevents foreign matter from adhering to the surface of the photomask and allows exposure light to pass through during exposure. Foreign matter includes dust. Examples of the exposure light include deep ultraviolet (DUV: Deep UltraViolet) light, EUV, and the like. EUV indicates light having a wavelength of 5 nm to 30 nm.

[0069] The pellicle film covers the entire opening on one end face side of the through-hole of the pellicle frame. The pellicle film may be directly supported on one end face of the pellicle frame, or may be supported via an adhesive layer (hereinafter, also referred to as "film adhesive layer"). The film adhesive layer may be a cured product of a known adhesive.

[0070] The film thickness of the pellicle film is preferably 1 nm to 200 nm. The material of the pellicle film is not particularly limited, and examples thereof include carbon-based materials, SiN, polysilicon, etc. The carbon-based material includes carbon nanotubes (hereinafter, referred to as "CNT"). Among them, the material of the pellicle film 12 preferably includes CNT. The CNT may be single-walled CNT or multi-walled CNT. The pellicle film may have a non-woven fabric structure. The non-woven fabric structure is formed by, for example, fibrous CNT.

[0071] (1.6) Protective film In the embodiment, the pellicle may optionally include a protective film (liner). The protective film protects at least the surface of the adhesive layer that contacts the photomask. The protective film is peelable from the adhesive layer. The thickness of the protective film is preferably 5 μm to 500 μm, more preferably 30 μm to 200 μm. Examples of the material of the protective film include polyester. A release agent may be coated on the surface of the protective film that contacts the adhesive layer. Examples of the release agent include silicone-based release agents and fluorine-based release agents.

[0072] (1.7) Photomask The pellicle according to the embodiment may be provided on the photomask. The photomask includes a photomask and the pellicle according to the embodiment. The photomask has a pattern. The pellicle according to the embodiment is attached to the surface of the photomask that has the pattern. Since the photomask blank according to the embodiment includes a pellicle, the pellicle is less likely to peel off from the photomask even when exposed to a high-temperature environment (e.g., 50°C to 60°C).

[0073] The photomask may be formed by laminating, for example, a support substrate, a reflective layer, and an absorber layer in this order. By partially absorbing light (e.g., EUV) in the absorber layer, a desired image is formed on a sensitive substrate (e.g., a semiconductor substrate with a photoresist film). Examples of the reflective layer include a multilayer film of molybdenum (Mo) and silicon (Si). The material of the absorber layer may be a material with high absorbability for EUV or the like. Examples of materials with high absorbability for EUV or the like include chromium (Cr), tantalum nitride, and the like.

[0074] (1.8) Exposure apparatus The pellicle according to the embodiment may be provided in an exposure apparatus. The exposure apparatus includes a light source, a photomask blank according to the embodiment, and an optical system. The light source emits exposure light. The optical system guides the exposure light emitted from the light source to the photomask blank. The photomask blank is arranged such that the exposure light emitted from the light source passes through the pellicle film and irradiates the photomask. In addition to being able to form a pattern (e.g., a line width of 32 nm or less) miniaturized by EUV or the like, the exposure apparatus according to the embodiment can perform pattern exposure with reduced resolution failure due to foreign matter even when using EUV, which is likely to cause resolution failure due to foreign matter. The exposure light is preferably EUV. Since EUV has a short wavelength, it is easily absorbed by gases such as oxygen or nitrogen. Therefore, exposure using EUV light is performed in a vacuum environment.

[0075] (1.9) Method for manufacturing a pellicle The method for manufacturing a pellicle according to the embodiment is a method for manufacturing a pellicle according to the embodiment, and includes a pellicle film attaching step and an adhesive layer forming step described later. Thereby, a pellicle with a swelling degree of the adhesive layer of 200% or less can be obtained. The execution order of the pellicle film attaching step and the adhesive layer forming step is not particularly limited.

[0076] (1.9.1) Pericle film attachment process In the pericle film attachment process, the pericle film is attached to one end face of the pericle frame. The method of attaching the pericle film to one end face of the pericle frame is not particularly limited. For example, a known adhesive is applied to one end face of the pericle frame to form an adhesive layer for the film, and the pericle film is placed on the adhesive layer for the film.

[0077] (1.9.2) Adhesive layer formation process In the adhesive layer formation process, the above-described coating composition is applied to the other end face of the pericle frame and heated to form an adhesive layer. As a result, the coating composition dries and cures to obtain an adhesive composition (adhesive layer).

[0078] (1.9.2.1) Coating method The method of applying the coating composition to the other end face of the pericle frame is not particularly limited, and examples include using a dispenser. The thickness of the coating composition is preferably 0.1 mm to 4.5 mm, more preferably 0.1 mm to 3.5 mm, and even more preferably 0.2 mm to 2 mm.

[0079] (1.9.2.2) Heating and drying The method of heating the coating composition is not particularly limited, and known methods can be used. The temperature for heating the coating composition is appropriately selected according to the boiling points of the solvent and residual monomers, the decomposition temperature of the (meth)acrylic acid alkyl ester copolymer, etc., and is preferably 50°C to 200°C, more preferably 60°C to 190°C.

[0080] By heating the coating composition, volatile compounds such as the solvent and residual monomers are removed from the adhesive layer. When the coating composition contains a crosslinking agent, the functional group of the (meth)acrylic acid alkyl ester copolymer and the crosslinking agent react by heating to form a crosslinked structure in the adhesive layer, resulting in a reaction product of the (meth)acrylic acid alkyl ester copolymer and the crosslinking agent. By this heat drying, the adhesive layer adheres to the surface of the pellicle frame, and the pellicle frame and the adhesive layer are integrated.

[0081] (2) Modified Example The pellicle according to the modified example of the present disclosure includes a pellicle frame, a pellicle film supported on one end face of the pellicle frame, and an adhesive layer provided on the other end face of the pellicle frame. The adhesive layer contains a copolymer of a (meth)acrylic acid alkyl ester monomer and a monomer having a functional group reactive with at least one of an isocyanate group, an epoxy group, and an acid anhydride (functional group-containing monomer). The (meth)acrylic acid alkyl ester monomer may have at least one of an alkyl group having 1 to 3 carbon atoms and an alicyclic alkyl group.

[0082] In the modified example, since the pellicle has the above configuration, outgas is less likely to be generated.

[0083] The pellicle according to the modified example comprises that the adhesive layer contains the copolymer and the (meth)acrylic acid alkyl ester monomer has at least one of an alkyl group having 1 to 3 carbon atoms and an alicyclic alkyl group. Other than not having to have the swelling degree represented by the formula (A) of the adhesive layer being 200% or less, it is the same as the pellicle according to the embodiment. The description of the modified example of the present disclosure can incorporate the description of the embodiment of the present disclosure. the above

[0084] ​(Meta)acrylic acid alkyl ester monomer, the content of (meta)acrylic acid alkyl ester monomer, functional group-containing monomer, and the content of functional group-containing monomer are the same as those of the (meta)acrylic acid alkyl ester monomer, the content of (meta)acrylic acid alkyl ester monomer, functional group-containing monomer, and the content of functional group-containing monomer in the embodiment.

[0085] In the modification, it is preferable that the degree of swelling is 200% or less. The degree of swelling is the same as the degree of swelling in the embodiment.

[0086] In the modification, for the pellicle, it is preferable that the outgassing amount obtained by converting the gas amount when performing the above (a) to (d) in this order into n-decane is 0.2 μg or less. The outgassing amount is the same as the outgassing amount in the embodiment.

[0087] In the modification, the pellicle includes an adhesive layer. The adhesive layer is the same as the adhesive layer in the embodiment.

[0088] The glass transition temperature Tg of the adhesive layer is preferably -25°C to 10°C. The glass transition temperature Tg of the adhesive layer is the same as the glass transition temperature Tg of the adhesive layer in the embodiment.

[0089] The coating composition is the same as the coating composition in the embodiment.

[0090] In the modification, the pressure-sensitive adhesive composition contains an acrylic pressure-sensitive adhesive. The acrylic pressure-sensitive adhesive is the same as the acrylic pressure-sensitive adhesive in the embodiment.

[0091] The content of the (meta)acrylic acid alkyl ester monomer is preferably 80 parts by mass to 99.5 parts by mass with respect to 100 parts by mass of the total amount of the monomers constituting the copolymer. The content of the functional group-containing monomer is preferably, for example, 1 part by mass to 20 parts by mass with respect to 100 parts by mass of the total amount of the monomers constituting the copolymer. The pressure-sensitive adhesive layer contains a reaction product of the copolymer and a crosslinking agent, and the content of the crosslinking agent is preferably 0.002 parts by mass to 3.000 parts by mass with respect to 100 parts by mass of the total amount of the monomers constituting the copolymer.

[0092] The thickness of the pressure-sensitive adhesive layer is the same as that of the pressure-sensitive adhesive layer in the embodiment.

[0093] In a modified example, the pellicle includes a pellicle frame. The pellicle frame is the same as the pellicle frame in the embodiment.

[0094] In a modified example, the pellicle may optionally include a protective film (liner). The protective film is the same as the protective film in the embodiment.

[0095] In a modified example, the pellicle may be provided on the exposure original plate. The exposure original plate includes a photomask and a pellicle according to the modified example. The photomask has a pattern. The pellicle according to the modified example is attached to the surface of the photomask on the side having the pattern. Since the exposure original plate includes the pellicle according to the modified example, the pellicle is less likely to peel off from the photomask even when exposed to a high-temperature environment (for example, 50°C to 60°C). The photomask is the same as the photomask in the embodiment.

[0096] In a modified example, the pellicle may be provided in the exposure apparatus. The exposure apparatus includes a light source, an exposure original plate according to the modified example, and an optical system. The light source emits exposure light. The optical system guides the exposure light emitted from the light source to the exposure original plate. The exposure original plate is arranged such that the exposure light emitted from the light source passes through the pellicle film and irradiates the photomask. In addition to being able to form a pattern (for example, a line width of 32 nm or less) miniaturized by EUV or the like, the exposure apparatus according to the modified example can perform pattern exposure with reduced resolution failure due to foreign matter even when using EUV, which is likely to cause resolution failure due to foreign matter. In the modified example, the exposure light is preferably EUV. Since EUV has a short wavelength, it is easily absorbed by gases such as oxygen or nitrogen. Therefore, exposure with EUV light is performed in a vacuum environment.

[0097] The method for manufacturing a pellicle according to the modified example is the same as the method for manufacturing a pellicle in the embodiment.

Example

[0098] Hereinafter, the present disclosure will be described in more detail by way of examples, but the invention of the present disclosure is not limited to these examples only.

[0099] Each component used in the examples and comparative examples is as follows. <(Meth)acrylic acid alkyl ester monomer> · EA: Ethyl acrylate (number of carbon atoms in the alkyl group: 2) · MMA: Methyl methacrylate (number of carbon atoms in the alkyl group: 1) · BA: Butyl acrylate (number of carbon atoms in the alkyl group: 4) · CHA: Cyclohexyl acrylate (alicyclic alkyl group) <Functional group-containing monomer> · 4-HBA: 4-Hydroxybutyl acrylate · HEMA: 2-Hydroxyethyl methacrylate · GMA: Glycidyl methacrylate · IEMA-type modified HEMA: 2-Isocyanateethyl-type modified 2-Hydroxyethyl methacrylate <Crosslinking agent> · "Rikacid MH-700G" manufactured by Shin-Nippon Rika Co., Ltd. (alicyclic acid anhydride) · AIBN: 2,2'-Azobisisobutyronitrile (10-hour half-life temperature: 65°C) <Polymerization solvent> · Propyl acetate <Catalyst> · Amine-based catalyst: "U-CAT SA-102" manufactured by San-Apro Ltd. (chemical formula: (1 , octylate of 8-azabicyclo-(5.4.0)undecene-7)

[0100] (Example 1) (Meth)acrylic acid alkyl ester copolymer was prepared by a well-known method. Specifically, a reaction vessel equipped with a stirrer, thermometer, reflux condenser, dropping device, and nitrogen inlet tube was prepared. A polymerization solvent (180 parts by mass) was placed in the reaction vessel, and a mixture of EA / 4-HBA / HEMA / GMA / crosslinking agent (423.4 parts by mass) was charged at a mass ratio of 378 / 12.6 / 21 / 8.4 / 3.4. Under a nitrogen atmosphere, this reaction solution was reacted at 85 °C for 6 hours and then at 95 °C for 2 hours to obtain an acrylic copolymer solution with a non-volatile content (copolymer) concentration of 70% by mass (weight average molecular weight: 119,000).

[0101] To the obtained acrylic copolymer solution (143 parts by mass), a crosslinking agent (0.28 parts by mass) and a catalyst (0.93 parts by mass) were added and stirred and mixed to obtain a coating composition.

[0102] As shown in Figure 1, as the pellicle frame 14, an anodized aluminum pellicle frame (outer dimensions: 149 mm × 115 mm, frame height H: 4.5 mm, frame width W: 2 mm) was prepared. The prepared coating composition was applied to one end face of the pellicle frame 14 with a dispenser. This was dried at 100 °C for 120 minutes, and after placing a protective film on the dried coating, it was dried at 120 °C for 20 hours to form an adhesive layer 15 (thickness: 0.2 mm) composed of an adhesive composition. A pellicle film 12 was attached to the other end face of the pellicle frame 14 (the end face on the side where the adhesive layer 15 was not formed) via a film adhesive layer 13. Thereby, a pellicle 10 was obtained. Regarding the obtained pellicle 10, evaluation was carried out by the following method.

[0103] [Measurement of Swelling Degree] As a heating device, an oven ("DES830" manufactured by Yamato Scientific Co., Ltd.) was prepared. The pellet 10 was placed in the oven chamber. The entire pellet 10 was heated under the conditions of 120 °C for 20 hours. Thereby, mainly the gas caused by the unreacted substances of the raw materials of the adhesive layer was released from the pellet. Next, the pellet 10 was taken out of the oven chamber and left in an atmosphere of 25 °C to cool to room temperature. Next, a part of the adhesive layer 15 was cut to obtain a 10 mg test piece. A decane solution (manufactured by Fujifilm Wako Pure Chemical Corporation, "Wako Special Grade", standard content: capillary column GC concentration 99% or more) was prepared. The test piece was immersed in 10 ml of the decane solution at room temperature for 6 hours. Next, the test piece was taken out of the decane solution with tweezers, placed on a petri dish, and dried for 3 minutes. Next, the mass of the test piece was measured using "BM-252" (manufactured by AND Corporation). The measured value of the test piece was substituted into formula (A) to calculate the swelling degree. The calculation results are shown in Table 1.

[0104] [Measurement of Outgas Generation Amount] Separate from the pellet 10 used for the measurement of the swelling degree, a new pellet 10 without any processing was prepared. As a heating device, an oven ("DES830" manufactured by Yamato Scientific Co., Ltd.) was prepared. The pellet 10 was placed in the oven chamber. The entire pellet 10 was heated under the conditions of 120 °C for 20 hours. Thereby, mainly the gas caused by the unreacted substances of the raw materials of the adhesive layer was released from the pellet. A resin bag with a three-layer structure was prepared. The resin bag is formed by laminating, in this order, an outer equipment layer of the bag (material: polyethylene terephthalate (PET), thickness: 12 μm), an intermediate adhesive layer of the bag (material: urethane-based resin, thickness: 3 μm), and an inner sealant layer of the bag (material: polyethylene, thickness: 40 μm). Next, the pellet 10 was taken out of the oven chamber, sealed in the resin bag, and stored in an atmosphere of 25 °C for 2 weeks. After storage, the pellicle 10 was taken out of the bag, and the pellicle 10 and the adsorbent (product name: "TENAX TA", manufactured by GL Sciences Inc., mesh: 80 / 60, form: powder) were placed in the chamber of the heating device. The entire pellicle 10 was heated under the conditions of 50 °C for 4 hours. Thereby, the outgases generated from the pellicle 10 were adsorbed by the adsorbent. Next, the adsorbent was taken out of the chamber of the heating device and left in the atmosphere at 25 °C to cool to room temperature. Then, the adsorption amount of the outgases adsorbed by the adsorbent was measured by heating and extracting for 10 minutes under the following analysis equipment and analysis conditions using gas chromatography analysis method (GC / MS). The measured value of the adsorption amount of the outgases was converted into n-decane, and the obtained conversion value was taken as the generation amount of the outgases of the pellicle 10. This n-decane conversion amount was obtained by regarding the detection intensity of the generated gas obtained by GC Mass as the detection intensity of n-decane and applying the calibration curve of n-decane prepared in advance. The generation amount of the outgases of the obtained pellicle 10 is shown in Table 1. The allowable range of the generation amount of the outgases is 1.2 μg or less.

[0105] <Analysis equipment> Gas chromatography: "QP2010plus" (manufactured by Shimadzu Corporation) <Analysis conditions> Column: "DB-1" (inner diameter: 0.32 mm, length: 60.0 m, thickness: 1.00 μm) Scan range: 35 m / z to 450 m / z Ionization: 0.78 kV Carrier gas: He

[0106] [Measurement of glass transition temperature (Tg)] The glass transition temperature (Tg) of the pressure-sensitive adhesive composition (pressure-sensitive adhesive layer) before attaching the pellicle 10 onto the quartz glass substrate was measured in accordance with JIS K7112. Specifically, a differential scanning calorimeter (DSC: Differential scanning calorimetry) was used, with a heating rate of 20 °C / min and nitrogen Under the following conditions, the glass transition temperature (Tg) of the pressure-sensitive adhesive composition before attaching the pellicle 10 onto the quartz glass substrate was measured. The measurement results are shown in Table 1.

[0107] [Measurement of the weight average molecular weight (Mw) and number average molecular weight (Mn) of the (meth)acrylic acid alkyl ester copolymer] The conditions of the GPC used to measure the weight average molecular weight (Mw) and number average molecular weight (Mn) of the (meth)acrylic acid alkyl ester copolymer are as follows. <GPC conditions> Pump: "LC-10AD" manufactured by Shimadzu Corporation Oven: "CT020A" manufactured by Shimadzu Corporation Detector: "RI-101" manufactured by Showa Denko K.K. Data processing software: "Empower3" manufactured by Waters GPC column: "PLgel MIXED-B" (7.5×300 mm) × 2 columns manufactured by Agilent Technologies, Inc. Column temperature: 40°C Elution solvent: Tetrahydrofuran Flow rate: 1.0 mL / min Sample concentration: 0.1% (w / v) Sample injection volume: 100 μL Standard substance: Monodisperse polystyrene

[0108] (Example 2) EA, 4-HBA, and GMA were charged in the mass ratios shown in Table 1, and the reaction was carried out under the same conditions as in Example 1 to obtain an acrylic copolymer solution with a nonvolatile content concentration of 70% by mass (weight average molecular weight: 138,000). The obtained solution was applied and processed in the same manner as in Example 1, and various evaluations of the obtained pellicle 10 were carried out.

[0109] (Example 3) EA, MMA, 4-HBA, HEMA, and GMA were charged at the mass ratios shown in Table 1 and reacted under the same conditions as in Example 1 to obtain an acrylic copolymer solution with a non-volatile content concentration of 70% by mass (weight average molecular weight: 105,000). The obtained solution was coated and processed in the same manner as in Example 1, and various evaluations of the obtained pellicle 10 were carried out.

[0110] (Example 4) BA, CHA, 4-HBA, HEMA, and GMA were charged at the mass ratios shown in Table 1 and reacted under the same conditions as in Example 1 to obtain an acrylic copolymer solution with a non-volatile content concentration of 70% by mass (weight average molecular weight: 134,000). The obtained solution was coated and processed in the same manner as in Example 1, and various evaluations of the obtained pellicle 10 were carried out.

[0111] (Example 5) EA, BA, 4-HBA, and GMA were charged at the mass ratios shown in Table 1 and reacted under the same conditions as in Example 1 to obtain an acrylic copolymer sol liquid ution (weight average molecular weight: 134,000). The obtained solution was coated and processed in the same manner as in Example 1, and various evaluations of the obtained pellicle 10 were carried out.

[0112] (Comparative Example 1) BA and HEMA were reacted at a mass ratio of BA / HEMA of 90 / 8.9, and 2-isocyanatoethyl methacrylate was reacted with the reaction product of BA and HEMA so that the mass ratio of HEMA / 2-isocyanatoethyl methacrylate was 8.9 / 1.1 to prepare an acrylic copolymer solution with a non-volatile content concentration of 70% by mass and the mass ratios shown in Table 1 for BA, HEMA, and IEMA-modified HEMA. The prepared solution was coated and processed in the same manner as in Example 1, and various evaluations of the obtained pellicle 10 were carried out.

[0113]

Table 1

[0114] In Table 1, the “raw material monomer” refers to an alkyl (meth)acrylate monomer. In Table 1, the “copolymer solution” refers to an acrylic copolymer solution.

[0115] The pellicle of Comparative Example 1 includes a pellicle frame, a pellicle film, and an adhesive layer. In the pellicle of Comparative Example 1, the swelling degree of the adhesive layer was 227%, which was not 200% or less. Therefore, the outgas generation amount was 2.50 μg, which was not 1.2 μg or less. As a result, it was found that the pellicle of Comparative Example 1 is not a pellicle in which outgas is less likely to occur.

[0116] The pellicles of Examples 1 to 4 include a pellicle frame 14, a pellicle film 12, and an adhesive layer 15. In the pellicles of Examples 1 to 4, the swelling degree of the adhesive layer was 120 to 148%, which was 200% or less. Therefore, the outgas generation amount was 0.30 μg, which was 15% or less of that of Comparative Example 1 even in Example 4 where the outgas was the most. As a result, it was found that the pellicles of Examples 1 to 4 are pellicles in which outgas is less likely to occur.

[0117] The disclosure of Japanese Patent Application No. 2021-148632 filed on September 13, 2021 is incorporated herein by reference in its entirety. All documents, patent applications, and technical standards described in this specification are incorporated herein by reference to the same extent as if each individual document, patent application, and technical standard was specifically and individually stated to be incorporated by reference.

Claims

1. A pellicle frame, a pellicle film supported on one end face of the pellicle frame, and an adhesive layer provided on the other end face of the pellicle frame, characterized in that: the swelling degree of the adhesive layer represented by the following formula (A) is 200% or less, and the pellicle is provided. Formula (A): [(mass after immersion of a 10 mg test piece collected from the adhesive layer) / 10 mg]×100 (In the formula (A), the mass after immersion indicates the mass of the test piece after immersing the test piece in 10 ml of a decane solution having a capillary column GC concentration of 99.0% or more for 6 hours.)

2. The pellicle according to claim 1, wherein the glass transition temperature Tg of the adhesive layer is -25°C to 10°C.

3. The pellicle according to claim 1 or 2, wherein the adhesive layer contains a copolymer of an (alkyl)acrylate monomer and a monomer having a functional group reactive with at least one of an isocyanate group, an epoxy group, and an acid anhydride.

4. The pellicle according to claim 3, wherein the (alkyl)acrylate monomer has at least one of an alkyl group having 1 to 3 carbon atoms and an alicyclic alkyl group.

5. The pellicle according to claim 3, wherein the content of the (alkyl)acrylate monomer is 80 parts by mass to 99.5 parts by mass with respect to 100 parts by mass of the total amount of the monomers constituting the copolymer.

6. The pellicle according to claim 3, wherein the content of the monomer having a functional group is 0.5 parts by mass to 20 parts by mass with respect to 100 parts by mass of the total amount of the monomers constituting the copolymer.

7. The adhesive layer contains a reaction product of the copolymer and a crosslinking agent, and the content of the crosslinking agent is 0.002 parts by mass to 3.000 parts by mass with respect to 100 parts by mass of the total amount of the monomers constituting the copolymer. The pellicle according to claim 3.

8. The outgas generation amount obtained by converting the gas amount when the following (a) to (d) are carried out in this order into n-decane is 1.5 μg or less, and the pellicle according to claim 1 or 2 is provided. (a) Heating the pellicle under the conditions of 120°C and 20 hours (b) Sealing the pellicle in a resin bag and storing it for 2 weeks in an atmosphere of 25°C (c) Heating the pellicle under the conditions of 50°C and 4 hours and absorbing the released gas with an adsorbent (d) Heating the adsorbent for 10 minutes and measuring the gas amount

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