Protective film and protective film assembly

Abstract

The object of this invention is to provide a novel protective film that exhibits excellent transmittance to light with wavelengths suitable for photolithography, while ensuring mechanical strength and / or lightfastness. This invention provides a protective film (3) comprising a polysiloxane having a cage-like silsesquioxane structure, with wavelengths suitable for photolithography, for example, 190 nm to 440 nm.

Description

Technical Field

[0001] This invention relates to protective films and protective film assemblies. Background Technology

[0002] In patterning processes for electronic devices, a dustproof unit known as a protective film assembly is commonly used. The protective film assembly consists of a transparent polymer film (hereinafter referred to as the "protective film") that is opened and then adhered to a frame. It also functions to prevent foreign matter from adhering to photomasks and reticles.

[0003] Regarding the materials for the protective film, Patent Document 1 describes a protective film material formed from polyladera siloxane, which has repeating units represented by a specific general formula in its molecule. Patent Document 1 reports that by using this protective film component material to construct the protective film, the degradation of the protective film component material can be suppressed when exposed to light using a short-wavelength laser.

[0004] For example, Patent Document 2 describes a protective film for ultraviolet light with a wavelength of 140-200 nm, characterized in that it contains an organic polymer, the thickness of which, when the film is formed, satisfies a specific relationship with the average light absorption rate in the wavelength region of the exposure light source. Patent Document 2 reports that, with this protective film, the degradation of the protective film material can be suppressed when exposed to short-wavelength light (e.g., KrF excimer laser and ArF excimer laser).

[0005] Existing technical documents

[0006] Patent documents

[0007] Patent Document 1: Japanese Patent Application Publication No. 4-166840

[0008] Patent Document 2: International Publication No. 98 / 36324 Summary of the Invention

[0009] The problem that the invention aims to solve

[0010] However, given the recent trend of miniaturization in patterns in electronic devices and the like, there is room for improvement in terms of the excellent transmittance of light with wavelengths suitable for photolithography for conventional protective films that use protective film component materials as described in Patent Documents 1 and 2.

[0011] Furthermore, with the further development of thin-film protective films, there is a need to solve the problem of how to ensure the mechanical strength and / or light resistance (durability against light) of the protective films.

[0012] The purpose of this invention is to provide a novel protective film that exhibits excellent transmittance to light with wavelengths suitable for photolithography, while ensuring mechanical strength and / or lightfastness.

[0013] In addition, the present invention aims to provide a protective film assembly using the protective film.

[0014] Methods for solving problems

[0015] One aspect of the present invention is described below. [1]

[0017] A protective film comprising a polysiloxane having a cage-like silsesquioxane structure. [2]

[0019] According to the protective film of Project 1, the polysiloxane has at least one structure selected from the group consisting of the structure shown in formula (i), the structure shown in formula (ii) and the structure shown in formula (iii).

[0020] [Chemistry 1]

[0021]

[0022] In equation (i), R 11 and R 12 Each of the following groups independently represents a siloxy group (-OSi), a hydrocarbon group with 1 to 12 carbon atoms, a hydrogen atom (-H), a hydroxyl group (-OH), or a fluorine group (-F) constituting the above-mentioned polysiloxane. In formula (i), there are a total of 4 R groups. 11 And a total of 4 R 12 At least two of them represent the siloxy groups (-OSi) that constitute the above-mentioned polysiloxane.

[0023] [Chemistry 2]

[0024]

[0025] {In equation (ii), R} 21 and R 22 Each of the following groups can be independently represented: a hydrocarbon group (-H), a hydrogen atom (-H), a hydroxyl group (-OH), or a fluorine group (-F) with 1 to 12 carbon atoms. 23 and R 24 Each of the following groups independently represents a siloxy group (-OSi), a hydrocarbon group with 1 to 12 carbon atoms, a hydrogen atom (-H), a hydroxyl group (-OH), or a fluorine group (-F) constituting the above-mentioned polysiloxane. In formula (ii), there are a total of 2 R groups. 23 And a total of 2 R 24 At least two of them are siloxy groups (-OSi) constituting the above-mentioned polysiloxane.

[0026] [Chemistry 3]

[0027]

[0028] {In equation (iii), R} 31 and R 32 Each of the following groups independently represents a siloxy group (-OSi), a hydrocarbon group with 1 to 12 carbon atoms, a hydrogen atom (-H), a hydroxyl group (-OH), or a fluorine group (-F) constituting the above-mentioned polysiloxane. Specifically, formula (iii) contains a total of 5 R groups. 31 And a total of 5 R 32 At least two of them are siloxy groups (-OSi) constituting the above-mentioned polysiloxane. [3]

[0030] According to the protective film of Project 1 or 2, the polysiloxane has at least one structure selected from the group consisting of the structure shown in Formula (I-1), the structure shown in Formula (II-1), and the structure shown in Formula (III-1).

[0031] [Chemistry 4]

[0032]

[0033] In equation (I-1), R 11 R 12 and R 41 Each group independently represents a hydrocarbon group (-H), hydrogen atom (-H), hydroxyl group (-OH), or fluorine group (-F) with 1 to 12 carbon atoms, and n represents an integer from 1 to 30.

[0034] [Chemistry 5]

[0035]

[0036] In equation (II-1), R 21 R 22 R 23 and R 41 Each group independently represents a hydrocarbon group (-H), hydrogen atom (-H), hydroxyl group (-OH), or fluorine group (-F) with 1 to 12 carbon atoms, and n represents an integer from 1 to 30.

[0037] [Chemistry 6]

[0038]

[0039] In equation (III-1), R 31 R 32 and R 41Each group independently represents a hydrocarbon group (-H), hydrogen atom (-H), hydroxyl group (-OH), or fluorine group (-F) with 1 to 12 carbon atoms, and n represents an integer from 1 to 30. [4]

[0041] According to the protective film of Project 3, in the above-mentioned polysiloxane, the proportion of structural units from the structures shown in formulas (i) to (iii) is 50% by mass or more, and / or the proportion of structures shown in formulas (I-1) to (III-1) is 50% by mass or more. [5]

[0043] A protective film assembly comprising a frame and a protective film adhered to the frame, wherein the protective film is any one of items 1 to 4. [6]

[0045] A formulation for making a protective film contains a polysiloxane having a cage-like silsesquioxane structure.

[0046] Invention Effects

[0047] According to the present invention, a novel protective film can be provided that exhibits excellent transmittance to light having a wavelength suitable for photolithography, and can ensure mechanical strength and / or lightfastness.

[0048] Furthermore, according to the present invention, a protective film assembly using the protective film can be provided. Attached Figure Description

[0049] Figure 1 This is a diagram showing an example of the configuration of the protective film assembly according to this embodiment. Detailed Implementation

[0050] Hereinafter, embodiments of the present invention (hereinafter also referred to as "this embodiment") will be described. The present invention is not limited to this embodiment, and various modifications can be made within the scope of its spirit.

[0051] In this specification, when multiple structures represented by the same symbol exist in the same formula, unless otherwise specified, each structure may be chosen independently, and they may be the same or different. Similarly, when multiple structures represented by the same symbol exist in different formulas, unless otherwise specified, each structure may be chosen independently, and they may be the same or different. In the chemical formulas, the abbreviation "Me" represents methyl (-CH3), and the abbreviation "Ph" represents phenyl (-C6H5).

[0052] In addition, the upper or lower limit of the numerical range recorded in this specification can be replaced with the upper or lower limit of other corresponding numerical ranges recorded in different stages, and can be further replaced with the corresponding values ​​recorded in the embodiments.

[0053] Furthermore, in this specification, the term "process" includes not only independent processes, but also processes that cannot be clearly distinguished from others, as long as they achieve the function of that process. In the accompanying drawings, for further clarity, scales, shapes, and lengths are sometimes exaggerated.

[0054] [Implementation Method 1]

[0055] <Protective film>

[0056] The protective film disclosed herein (hereinafter, sometimes referred to as "this protective film") comprises a polysiloxane having a cage-like silsesquioxane structure (hereinafter, sometimes referred to as "this polysiloxane").

[0057] The inventors have conducted extensive research in search of novel protective films that can be used in photolithography processes utilizing j-lines, i-lines, h-lines, g-lines, etc. As a result, they discovered that by using this polysiloxane as a material, a protective film exhibiting excellent transmittance to light with wavelengths suitable for photolithography can be achieved. The protective film disclosed herein exhibits excellent transmittance to light with wavelengths suitable for photolithography, such as light with wavelengths from 190 nm to 440 nm, particularly light with wavelengths from 290 nm to 440 nm, and light with wavelengths of 193 nm and 248 nm. Therefore, it can meet the requirements of next-generation electronic devices, such as the requirement for further miniaturization of patterns.

[0058] Furthermore, according to this protective film, not only is the transmittance excellent, but the mechanical strength, such as puncture strength, and / or light resistance (durability to light, for example, durability to light with wavelengths of 190 nm to 440 nm, especially durability to light with wavelengths of 290 nm to 440 nm, and durability to light with wavelengths of 193 nm and 248 nm) are also excellent. Therefore, from the viewpoint of transmittance, mechanical strength, and / or light resistance, this disclosure provides a highly practical protective film.

[0059] Polysiloxanes with cage-like silsesquioxane structures

[0060] This polysiloxane has a cage-like silsesquioxane structure.

[0061] Here, "sesquioxane" refers to, for example, a polysiloxane composed solely of units formed by the condensation of trifunctional silanes, namely the T units described below.

[0062] [Chemistry 7]

[0063]

[0064] (In the above unit, R is any substituent.)

[0065] In particular, "cage-type silsesquioxane" refers to (oligomeric) siloxanes composed of the aforementioned T units {composition formula: (RSiO 1.5 ) m ,5≤m≤100}, and form a polyhedral structure.

[0066] In addition, "polysiloxane has a cage-like silsesquioxane structure" means that a "cage-like silsesquioxane" structure is introduced into the siloxane skeleton (...Si-O-Si...) of the polysiloxane.

[0067] It should be noted that the term "cage-type silsesquioxane" in this disclosure includes either a "complete cage-type silsesquioxane" with a closed cage structure or an "incomplete cage-type silsesquioxane" with a partially open cage structure.

[0068] In cage-like silsesquioxanes, the composition formula (RSiO) 1.5 ) m In the formula, m is preferably 6 or more, more preferably 7 or more, even more preferably 8 or more, preferably 50 or less, more preferably 20 or less, and even more preferably 12 or less. When m in the composition is within the above range, it is easier to ensure the light transmittance, mechanical strength, and light resistance of the protective film. Furthermore, m can be an integer.

[0069] The polysiloxane preferably has at least one structure selected from the group consisting of the structure shown in formula (i), the structure shown in formula (ii), and the structure shown in formula (iii).

[0070] [Chemistry 8]

[0071]

[0072] In equation (i), R 11 and R 12 Each of the following groups independently represents a siloxy group (-OSi), a hydrocarbon group with 1 to 12 carbon atoms, a hydrogen atom (-H), a hydroxyl group (-OH), or a fluorine group (-F) constituting the above-mentioned polysiloxane. In formula (i), there are a total of 4 R groups. 11 And a total of 4 R 12 At least two of them represent the siloxy groups (-OSi) that constitute the above-mentioned polysiloxane.

[0073] [Chemistry 9]

[0074]

[0075] {In equation (ii), R} 21 and R 22 Each of the following groups can be independently represented: a hydrocarbon group (-H), a hydrogen atom (-H), a hydroxyl group (-OH), or a fluorine group (-F) with 1 to 12 carbon atoms. 23 and R 24 Each of the following groups independently represents a siloxy group (-OSi), a hydrocarbon group with 1 to 12 carbon atoms, a hydrogen atom (-H), a hydroxyl group (-OH), or a fluorine group (-F) constituting the above-mentioned polysiloxane. In formula (ii), there are a total of 2 R groups. 23 And a total of 2 R 24 At least two of them are siloxy groups (-OSi) constituting the above-mentioned polysiloxane.

[0076] [Chemistry 10]

[0077]

[0078] {In equation (iii), R} 31 and R 32 Each of the five R groups independently represents a siloxy group (-OSi), a hydrocarbon group with 1 to 12 carbon atoms, a hydrogen atom (-H), a hydroxyl group (-OH), or a fluorine group (-F) constituting the polysiloxane. Specifically, formula (iii) contains a total of five R groups. 31 And a total of 5 R 32 At least two of them are siloxy groups (-OSi) that constitute polysiloxanes.

[0079] By having these structures, it is easier to ensure the light transmittance, mechanical strength, and light resistance of the protective film.

[0080] This polysiloxane may have multiple different structures as shown in formula (i), multiple different structures as shown in formula (ii), multiple different structures as shown in formula (iii), a structure as shown in formula (i) and a structure as shown in formula (ii), a structure as shown in formula (i) and a structure as shown in formula (iii), a structure as shown in formula (ii) and a structure as shown in formula (iii), a structure as shown in formula (i) and a structure as shown in formula (ii), and in addition, it may have all the structures shown in formulas (i) to (iii).

[0081] R in equations (i) to (iii) above 11 R 12 R 21 R 22 R 31 and R 32It can be easily achieved by using raw materials containing these compounds to synthesize polysiloxanes, or by introducing them during the synthesis of polysiloxanes. Furthermore, it is also easy to introduce R by heat treatment such as rapid annealing of the hydrocarbon groups, or by removing the hydrocarbon groups through UV irradiation and ozone treatment. 11 R 12 R 21 R 22 R 31 and R 32 As a substituent. R 11 R 12 R 21 R 22 R 31 and R 32 It can be easily achieved through appropriate methods corresponding to their types.

[0082] In equations (i) to (iii) above, R is used as 11 R 12 R 21 R 22 R 31 and R 32 Preferably, at least one of hydrogen atom (-H), hydroxyl group (-OH), and fluorine group (-F) is selected, in which case it is easy to achieve a protective film with excellent transmittance of short-wavelength light. From the same point of view, R in the above formula (i) is preferred. 11 and R 12 The ratio of hydrogen atoms (-H), hydroxyl groups (-OH), and fluorine groups (-F) in formula (ii) above, and R 21 and R 22 The ratio of hydrogen atoms (-H), hydroxyl groups (-OH), and fluorine groups (-F) in formula (iii) above, and R 31 and R 32 The proportions of hydrogen atoms (-H), hydroxyl groups (-OH), and fluorine groups (-F) are high, preferably 10% or more, more preferably 20% or more, more preferably 30% or more, and even more preferably 40% or more of these substituents are at least one selected from the group consisting of hydrogen atoms (-H), hydroxyl groups (-OH), and fluorine groups (-F). This proportion can be 100% or less, 90% or less, 80% or less, or 70% or less.

[0083] The weight-average molecular weight of this polysiloxane can be 2,000 or more and 10,000,000 or less, preferably 5,000 or more, more preferably 7,000 or more, and further preferably 2,000,000 or less, more preferably 1,000,000 or less. When the weight-average molecular weight is within the above range, it is easier to ensure the light transmittance, mechanical strength, and light resistance of the protective film.

[0084] It should be noted that the weight-average molecular weight can be determined based on the chromatogram measured using gel permeation chromatography (GPC).

[0085] (The structure shown in equation (i))

[0086] In the above formula (i), "a total of 4 R" 11 And a total of 4 R 12 "At least two of the siloxy groups (-OSi) constituting the polysiloxane" means that, in formula (i), R 11 and R 12 At least two of the total eight Rs are bonded to the siloxy groups (-OSi) that constitute the polysiloxane, i.e., the repeating units are connected to each other.

[0087] In addition, the "hydrocarbon group" in formula (i) above can be any hydrocarbon group with a straight chain structure, a branched chain structure and / or a cyclic structure. It can also be a hydrocarbon group with carbon-carbon unsaturated bonds (e.g., carbon-carbon double bond structure and carbon-carbon triple bond structure) or a hydrocarbon group without carbon-carbon unsaturated bonds.

[0088] When a "hydrocarbon group" has a cyclic structure, the ring can be an alicyclic or an aromatic ring. Therefore, aliphatic and aromatic hydrocarbon groups with a single cyclic structure (i.e., monocyclic) and those with multiple cyclic structures (i.e., polycyclic) are also included in the concept of "hydrocarbon group." Of course, groups referred to as alkyl, alkenyl, alkynyl, aryl, etc., are also included in the concept of "hydrocarbon group."

[0089] When R 11 and / or R 12 When the group is a hydrocarbon group, the number of carbon atoms is preferably 10 or less, more preferably 8 or less, even more preferably 6 or less, and particularly preferably 4 or less. The number of carbon atoms can be 1 or more.

[0090] When R 11 and / or R 12 When the group is a hydrocarbon group, examples of such hydrocarbon groups include methyl (-CH3), ethyl (-CH2CH3), vinyl (-CH=CH2), n-propyl (-CH2CH2CH3), isopropyl (-CH(CH3)2), n-butyl (-CH2CH2CH2CH3), sec-butyl (-CH2CH(CH3)2), tert-butyl (-C(CH3)2), and cyclohexyl (-C6H) 11 ), phenyl (-C6H5), etc.

[0091] (The structure shown in equation (ii))

[0092] In the above formula (ii), "a total of 2 R" 21 And a total of 2 R 22"At least two of the siloxy groups (-OSi) constituting the polysiloxane" in formula (ii) means that R 21 and R 22 At least two of the four Rs in total are bonded to the siloxy groups (-OSi) that constitute the polysiloxane, i.e., the repeating units are connected to each other.

[0093] Regarding the "hydrocarbon group" in formula (ii) above, please refer to the explanation in formula (i) above.

[0094] When R 21 and / or R 22 When the group is a hydrocarbon group, the number of carbon atoms is preferably 10 or less, more preferably 8 or less, even more preferably 6 or less, and particularly preferably 4 or less. The number of carbon atoms can be 1 or more.

[0095] When R 21 and / or R 22 When the group is a hydrocarbon group, examples of such hydrocarbon groups include methyl (-CH3), ethyl (-CH2CH3), vinyl (-CH=CH2), n-propyl (-CH2CH2CH3), isopropyl (-CH(CH3)2), n-butyl (-CH2CH2CH2CH3), sec-butyl (-CH2CH(CH3)2), tert-butyl (-C(CH3)2), and cyclohexyl (-C6H) 11 ), phenyl (-C6H5), etc.

[0096] (The structure shown in equation (iii))

[0097] In equation (iii) above, "a total of 5 R" 31 And a total of 5 R 32 "At least two of the siloxy groups (-OSi) constituting the polysiloxane" in formula (iii) means that R 31 and R 32 At least two of the total 10 R's are bonded to the siloxy groups (-OSi) that make up the polysiloxane, i.e., the repeating units are connected to each other.

[0098] In equation (iii) above, the term "hydrocarbon group" can be referred to the explanation in equation (i) above.

[0099] When R 31 and / or R 32 When the group is a hydrocarbon group, the number of carbon atoms is preferably 10 or less, more preferably 8 or less, even more preferably 6 or less, and particularly preferably 4 or less. The number of carbon atoms can be 1 or more.

[0100] When R 31 and / or R 32When the group is a hydrocarbon group, examples of such hydrocarbon groups include methyl (-CH3), ethyl (-CH2CH3), vinyl (-CH=CH2), n-propyl (-CH2CH2CH3), isopropyl (-CH(CH3)2), n-butyl (-CH2CH2CH2CH3), sec-butyl (-CH2CH(CH3)2), tert-butyl (-C(CH3)2), and cyclohexyl (-C6H) 11 ), phenyl (-C6H5), etc.

[0101] For cage-like silsesquioxane structures, as represented by formula (i) above, at least one of the following formulas can be cited as examples.

[0102] [Chemistry 11]

[0103]

[0104] As a structure represented by equation (ii) above, at least one of the following equations can be cited as an example of a structure.

[0105] [Chemistry 12]

[0106]

[0107] In addition, as the structure shown in equation (iii) above, at least one of the following equations can be cited as an example of the structure shown in the following equations.

[0108] [Chemistry 13]

[0109]

[0110] "monomer"

[0111] This polysiloxane can be formed by using a cage-like silsesquioxane as a monomer and condensing it with the silanol group (Si-OH) of the siloxane.

[0112] (For monomers that form the structure shown in formula (i))

[0113] The monomers used to form the structure shown in formula (i) can be prepared by, for example, the synthetic pathway shown below.

[0114] [Chemistry 14]

[0115]

[0116] This synthetic route represents an example of the synthesis of cage-like silsesquioxanes with two different substituents on the opposed faces (e.g., "Cl-" and "Me-" on the upper and lower opposed faces in the paper). Cage-like silsesquioxanes with two different substituents on the opposed faces are particularly known as "Janus cubes".

[0117] According to the above synthetic route, hydrolyzable functional groups such as Si-Cl can be introduced, thus the resulting cage-like silsesquioxane can be easily used as a monomer for this polysiloxane. It should be noted that, regarding the preparation of monomers used to form the structure shown in formula (i), please refer to International Publication Nos. 2017 / 065311 and 2018 / 101213, etc.

[0118] As monomers for forming the structure shown in formula (i), cage-like silsesquioxanes represented by at least any one of the following formulas (mi-1) to (mi-3) can be cited.

[0119] [Chemistry 15]

[0120]

[0121] In equations (mi-1) to (mi-3), R 11 and R 12 Each of these groups independently represents a hydrocarbon group (1-12 carbon atoms), a hydrogen atom (-H), a hydroxyl group (-OH), or a fluorine group (-F), and X independently represents a halogen atom, a hydrogen atom (-H), or an alkoxy group (1-8 carbon atoms).

[0122] In the above formulas (mi-1) to (mi-3), the meaning of "hydrocarbon group" is the same as that of "hydrocarbon group" in formula (i) above.

[0123] That is, the number of carbon atoms in the hydrocarbon group is preferably 10 or less, more preferably 8 or less, even more preferably 6 or less, and particularly preferably 4 or less. Examples of hydrocarbon groups include methyl (-CH3), ethyl (-CH2CH3), vinyl (-CH=CH2), n-propyl (-CH2CH2CH3), isopropyl (-CH(CH3)2), n-butyl (-CH2CH2CH2CH3), sec-butyl (-CH2CH(CH3)2), tert-butyl (-C(CH3)2), and cyclohexyl (-C6H) 11 ), phenyl (-C6H5), etc.

[0124] In the above formulas (mi-1) to (mi-3), examples of "halogen atoms" include chlorine atoms (chlorine group), and examples of "alkoxy groups" include methoxy groups (-OCH3).

[0125] (For monomers that form the structure shown in formula (ii))

[0126] The monomers used to form the structure shown in formula (ii) can be prepared by, for example, the synthetic route shown below.

[0127] [Chemistry 16]

[0128]

[0129] It should be noted that, regarding the preparation of monomers for the structure shown in formula (ii), reference can be made to Japanese Patent Application Publication No. 2011-190413, Japanese Patent Application Publication No. 2015-155541, Japanese Patent Application Publication No. 2017-14320 and Japanese Patent Application Publication No. 2021-178892, etc.

[0130] As a monomer for forming the structure shown in formula (ii), cage-like silsesquioxanes shown in formula (mii-1) can be cited as examples.

[0131] [Chemistry 17]

[0132]

[0133] In equation (mii-1), R 21 and R 22 Each of these groups independently represents a hydrocarbon group (1-12 carbon atoms), a hydrogen atom (-H), a hydroxyl group (-OH), or a fluorine group (-F), and X independently represents a halogen atom, a hydrogen atom (-H), or an alkoxy group (1-8 carbon atoms).

[0134] In the above formula (mii-1), the term "hydrocarbon group" has the same meaning as that explained in formula (i). Examples of "halogen atom" include chlorine atom (chloride group), and examples of "alkoxy group" include methoxy group (-OCH3).

[0135] (For monomers that form the structure shown in formula (iii))

[0136] Monomers used to form the structure shown in formula (iii) can be cage-like silsesquioxanes represented by at least any one of the following formulas (miii-1) to (miii-3).

[0137] [Chemistry 18]

[0138]

[0139] {In formula (miii-1)~(miii-3), R 31 and R 32 Each of these groups independently represents a hydrocarbon group (1-12 carbon atoms), a hydrogen atom (-H), a hydroxyl group (-OH), or a fluorine group (-F), and X independently represents a halogen atom, a hydrogen atom (-H), or an alkoxy group (1-8 carbon atoms).

[0140] In the above formula (miii-1), the term "hydrocarbon group" has the same meaning as that explained in formula (i). Examples of "halogen atom" include chlorine atom (chloride group), and examples of "alkoxy group" include methoxy group (-OCH3).

[0141] (copolymer)

[0142] This polysiloxane can be a polymer formed from any one of the aforementioned monomers, or a copolymer formed from multiple monomers including any one of the aforementioned monomers. When this polysiloxane is a copolymer, the multiple monomers constituting the copolymer may consist only of the aforementioned monomers, and may also include monomers other than those mentioned above (hereinafter referred to as "other monomers"), provided that this does not violate the spirit of the invention.

[0143] Other monomers include compounds represented by the formulas (miv-1) to (miv-2).

[0144] [Chemistry 19]

[0145]

[0146] In equations (miv-1) and (miv-2), R 41 Each of the following groups independently represents a hydrocarbon group (1-12 carbon atoms), a hydrogen atom (-H), a hydroxyl group (-OH), or a fluorine group (-F), respectively; X independently represents a halogen atom, a hydrogen atom (-H), a hydroxyl group (-OH), or an alkoxy group (1-8 carbon atoms), respectively; and m represents an integer from 2 to 10.

[0147] It should be noted that the compound represented by formula (miv-1) is usually called a silane, and the compound represented by formula (miv-2) is usually called a siloxane.

[0148] In the above formulas (miv-1) and (miv-2), "hydrocarbon group" has the same meaning as "hydrocarbon group" as described in formula (i) above.

[0149] That is, the number of carbon atoms in the hydrocarbon group is preferably 10 or less, more preferably 8 or less, even more preferably 6 or less, and particularly preferably 4 or less. Examples of hydrocarbon groups include methyl (-CH3), ethyl (-CH2CH3), vinyl (-CH=CH2), n-propyl (-CH2CH2CH3), isopropyl (-CH(CH3)2), n-butyl (-CH2CH2CH2CH3), sec-butyl (-CH2CH(CH3)2), tert-butyl (-C(CH3)2), and cyclohexyl (-C6H) 11 ), phenyl (-C6H5), etc.

[0150] In the above formulas (miv-1) and (miv-2), examples of "halogen atoms" include chlorine atoms (chlorine group), and examples of "alkoxy groups" include methoxy groups (-OCH3).

[0151] When the polysiloxane is a copolymer, it can be any one of alternating copolymers, random copolymers, and block copolymers.

[0152] It should be noted that the "polysiloxane having at least one structure selected from the group consisting of the structures shown in formulas (I-1) to (III-1)" described later can be treated as a block copolymer.

[0153] When the polysiloxane is a copolymer, the molar ratio of the cage-like silsesquioxane structure relative to the total mass of all monomers (when the total mass of all monomers is set to 100%) can be 1% or more and 90% or less, preferably 10% or more, more preferably 20% or more, further preferably 30% or more, and preferably 80% or less, more preferably 70% or less, further preferably 60% or less, and particularly preferably 55% or less. When the molar ratio of the cage-like silsesquioxane structure is within the above range, it is easier to ensure the light transmittance, mechanical strength, and light resistance of the protective film.

[0154] When the polysiloxane is a copolymer and contains other monomers, the ratio of the mass of the other monomers to the total mass of all monomers (when the total mass of all monomers is set to 100%) can be 1% or more and 90% or less, preferably 10% or more, more preferably 20% or more, even more preferably 30% or more, and preferably 80% or less, more preferably 70% or less, even more preferably 60% or less, and particularly preferably 55% or less.

[0155] On the other hand, from the viewpoint of obtaining the effect of the monomers used to form the structures shown in formulas (i) to (iii), among all the monomers, the mass of the other monomers is preferably less than the mass of the monomers used to form the structures shown in formulas (i) to (iii).

[0156] Here, the polysiloxane preferably has at least one structure selected from the group consisting of the structure shown in formula (I-1), the structure shown in formula (II-1), and the structure shown in formula (III-1).

[0157] [Chemistry 20]

[0158]

[0159] In equation (I-1), R 11 R 12 and R 41Each group independently represents a hydrocarbon group (-H), hydrogen atom (-H), hydroxyl group (-OH), or fluorine group (-F) with 1 to 12 carbon atoms, and n represents an integer from 1 to 30.

[0160] [Chemistry 21]

[0161]

[0162] In equation (II-1), R 21 R 22 R 23 and R 41 Each group independently represents a hydrocarbon group (-H), hydrogen atom (-H), hydroxyl group (-OH), or fluorine group (-F) with 1 to 12 carbon atoms, and n represents an integer from 1 to 30.

[0163] [Chemistry 22]

[0164]

[0165] In equation (III-1), R 31 R 32 and R 41 Each group independently represents a hydrocarbon group (-H), hydrogen atom (-H), hydroxyl group (-OH), or fluorine group (-F) with 1 to 12 carbon atoms, and n represents an integer from 1 to 30.

[0166] With these structures, it is easier to ensure the light transmittance, mechanical strength, and light resistance of the protective film.

[0167] In this polysiloxane, the proportion of structural units derived from the structures shown in formulas (i) to (iii) above is preferably 50% by mass or more, more preferably 65% ​​by mass or more, and even more preferably 80% by mass or more. Furthermore, in this polysiloxane, the proportion of the structures shown in formulas (I-1) to (III-1) above is preferably 50% by mass or more, more preferably 65% ​​by mass or more, even more preferably 80% by mass or more, and may also be 100% by mass.

[0168] If these ratios are within the above range, it is easier to ensure the light transmittance, mechanical strength, and light resistance of the protective film.

[0169] Various Compositions

[0170] The thickness of this protective film can be 0.10 μm or more and 10.0 μm or less, preferably 0.25 μm or more, more preferably 1.0 μm or more, and even more preferably 6.0 μm or less, more preferably 3.0 μm or less. When the film thickness is within the above range, it is easier to ensure the light transmittance, mechanical strength, and light resistance of the protective film.

[0171] The transmittance of this protective film for light with wavelengths of 190 nm or higher and 290 nm or lower is preferably 80% or higher and 100% or lower, more preferably 85% or higher, and even more preferably 90% or higher. The transmittance of this protective film for light with wavelengths of 290 nm or higher and 385 nm or lower is preferably 80% or higher and 100% or lower, more preferably 90% or higher, and even more preferably 95% or higher. It should be noted that the transmittance can be measured based on the method described in the embodiments.

[0172] The transmittance of this protective film for light with wavelengths of 360 nm or higher and 440 nm or lower is 80% or higher and 100% or lower, preferably 90% or higher, and more preferably 95% or higher. It should be noted that the transmittance can be measured based on the method described in the examples.

[0173] This protective film may contain only the layer containing this polysiloxane, or it may contain layers other than the layer containing this polysiloxane (hereinafter referred to as "other layers").

[0174] Other layers include, for example, layers with a lower refractive index than the film containing this polysiloxane (e.g., an anti-reflective layer). By including an anti-reflective layer, the light transmittance of this protective film is easily improved.

[0175] Materials used as anti-reflective layers include fluorinated polymers such as tetrafluoroethylene-vinylidene fluoride-hexafluoropropylene terpolymers, Teflon AF (trade name) manufactured by DuPont (a polymer with a cyclic structure in the main chain), CYTOP (trade name) manufactured by Asahi Glass, Algoflon (trade name) manufactured by Ausimont, polyfluoroacrylates, etc., calcium fluoride, magnesium fluoride, barium fluoride, etc.

[0176] The antireflective layer can be a polymer layer mainly containing polymers or an inorganic layer mainly containing inorganic materials. Regarding the method of forming the antireflective layer, spin coating is an example when the antireflective layer is a polymer layer, and thin film formation methods such as vacuum evaporation and sputtering are examples when the antireflective layer is an inorganic layer.

[0177] This protective film may have an uneven structure on its surface. This shape facilitates improved light transmittance. The shape of the protrusions is preferably a pyramidal shape, a conical shape, a truncated pyramidal shape, or a truncated conical shape. The protective film with the uneven structure can be manufactured by forming the protective film on a substrate with the uneven structure and on a film with the uneven structure.

[0178] Methods for manufacturing protective films

[0179] As a method for manufacturing this protective film, known methods and conditions for manufacturing protective films can be appropriately employed. Examples include forming a film from a solution that dissolves and / or disperses the polysiloxane onto a substrate and then drying it. Examples of film-forming methods include spin coating, roller coating, doctor blade coating, and casting, with spin coating being preferred. Examples of drying methods include heating using a hot plate, a cleanroom oven, infrared radiation, or far-infrared radiation.

[0180] Examples of substrates used in film formation include synthetic quartz, fused silica, alkali-free glass, low-alkali glass, soda-lime glass, and silicon wafers. Furthermore, the coefficient of linear expansion of the substrate at temperatures above 0°C and below 300°C is preferably 50 × 10⁻⁶. -7 Below m / ℃. Additionally, a demolding process can be performed on the surface of the substrate used during film formation.

[0181] <Protective membrane assembly>

[0182] The protective film assembly disclosed herein (hereinafter, sometimes simply referred to as "the protective film assembly") comprises a frame and a protective film adhered to the frame.

[0183] The following describes a preferred embodiment of the protective film assembly.

[0184] Figure 1 Figures (a) to (b) are diagrams illustrating an example of the configuration of the protective film assembly 1 of this disclosure, wherein... Figure 1 (a) is a perspective view of the protective film assembly 1. Additionally, Figure 1 (b) is Figure 1 The cross-sectional view along line AA in (a). In the figure, the arrows in the x, y, and z directions are shown orthogonally to each other, and these directions are... Figure 1 The corresponding ones in (a) to (b).

[0185] In addition, Figure 1 In (b), the photomask M of the protective film assembly 1 is also shown attached along the direction of the arrow.

[0186] As shown in the figure, the protective film assembly 1 includes a frame 2 and a protective film 3 adhered to the frame 2. The protective film assembly 1 can be mounted on the photomask M in such a way that it surrounds the circuit pattern (not shown) drawn on the photomask M. Therefore, the size and shape of each component in the protective film assembly 1 can be appropriately selected according to the photomask M or according to the circuit pattern drawn on the photomask M.

[0187] Protective Film

[0188] Unfold the protective film 3 and then stick it to the frame 2.

[0189] Here, in the protective film assembly 1, the aforementioned protective film is used as the protective film 3. Therefore, according to this disclosure, from the viewpoints of the transmissivity of the protective film 3, the mechanical strength of the protective film 3, and / or the light resistance of the protective film 3, a highly practical protective film assembly 1 can be provided.

[0190] The Frame

[0191] The frame 2 has a pair of long sides 2a and a pair of short sides 2b, so that when viewed from above (a projected view along the direction of arrow z), a rectangular opening Op is formed with these long sides 2a and short sides 2b as its edges.

[0192] In the case of small protective membrane assemblies, the length of the long side 2a can be 110mm or more and 180mm or less, and the length of the short side 2b can be 100mm or more and 150mm or less. In the case of large protective membrane assemblies, the length of the long side 2a can be 400mm or more, 800mm or more, or 2100mm or more, and the length of the short side 2b can be 150mm or more, 300mm or more, or 400mm or more.

[0193] The widths of the long side 2a and the short side 2b can be 1.8 mm or more and 30 mm or less, preferably 1.8 mm or more, more preferably 2.0 mm or more, even more preferably 4.0 mm or more, and preferably 25 mm or less, more preferably 19 mm or less.

[0194] The thickness of the long side 2a and the short side 2b can be 3.0 mm or more and 10 mm or less, preferably 2.5 mm or more, more preferably 3.0 mm or more, and preferably 8.0 mm or less, more preferably 7.0 mm or less.

[0195] The cross-sectional shapes of the long side 2a and the short side 2b can be rectangular, H-shaped, and T-shaped, respectively.

[0196] In this embodiment, the long side 2a and the short side 2b are respectively adopted as sides with an external shape that is approximately cuboid in shape. Therefore, the cross-sectional shape of the long side 2a and the short side 2b is rectangular.

[0197] Materials that can be used for frame 2 include aluminum, aluminum alloys (5000 series, 6000 series, 7000 series, etc.); iron and iron alloys; ceramics (SiC, AlN, Al2O3, etc.); ceramic-metal composites (Al-SiC, Al-AlN, Al-Al2O3, etc.); carbon steel; tool steel; stainless steel series; magnesium alloys; polycarbonate resin, acrylic resin, etc.

[0198] For the frame 2, it is preferable to have vents 4 that penetrate the interior and exterior of the space formed between the protective film 1 and the photomask M when the protective film 1 is adhered to the photomask M, with the aim of reducing the pressure difference between the inside and outside of the space. The size and number of vents 4 can be determined based on the volume of the space. When the protective film assembly 1 has vents 4, from the viewpoint of easily preventing foreign matter from entering the space, the frame 2 preferably has a filter 5 such as a porous membrane that covers the vents 4.

[0199] The frame 2 preferably has a membrane adhesive layer 6 for bonding the protective film 3. The membrane adhesive layer 6 can be disposed on one side of the frame 2, especially the side on which the protective film 3 is bonded. By having the membrane adhesive layer 6, the protective film 3 can be easily supported in an open state.

[0200] The membrane adhesive layer 6 can be formed by applying a membrane adhesive to the frame 2. Examples of membrane adhesives include epoxy, acrylic, silicone, and fluorine-based adhesives. The membrane adhesive can be cured as needed. Examples of curing methods include thermosetting, photocuring, and anaerobic curing.

[0201] The frame 2 preferably has a mask adhesive layer 7 for attaching to the photomask M. The mask adhesive layer 7 can be disposed on another side of the frame 2, particularly the side attached to the photomask M. By having the mask adhesive layer 7, the fixing and removal of the photomask M by the protective film 1 becomes easier.

[0202] The mask adhesive layer 7 can be formed by applying a mask adhesive to the frame 2. Examples of mask adhesives include hot melt adhesives (rubber adhesives and acrylic adhesives).

[0203] As the mask adhesive layer 7, a tape-like adhesive component can also be used. The tape-like adhesive component, for example, has adhesive layers on both sides of the substrate. The substrate can be, for example, acrylic or PVC-based sheets, or rubber-based, polyolefin-based, or polyurethane-based foams. The adhesive layer can be, for example, a layer containing rubber-based, acrylic-based, or silicone-based adhesives.

[0204] <Formulation solution used to make protective films>

[0205] Another aspect of the invention is a formulation for producing a protective film, which contains a polysiloxane having a cage-like silsesquioxane structure. Regarding the polysiloxane having a cage-like silsesquioxane structure, as described above. This formulation may contain a solvent.

[0206] [Other Implementation Methods]

[0207] This implementation method is not limited to the above-described manner and can be modified in various ways within its scope.

[0208] For example, the frame can have any external and internal shape for attaching the protective film and for enclosing the circuit pattern drawn on the photomask. The frame can also be configured to be segmentable. The protective film assembly can be fixed to the photomask by any clamp, in which case the frame can have any shape corresponding to the clamp.

[0209] The protective film can be pressed onto the frame, in which case the film adhesive layer can be omitted.

[0210] Example

[0211] The following examples and comparative examples illustrate this embodiment. However, this embodiment is not limited to the examples described below. Unless otherwise specified, all manufacturing, measurement, and evaluation processes were conducted at room temperature (25°C) and atmospheric pressure in the examples and comparative examples.

[0212] [The preparation solution used to make the protective film and the protective film itself]

[0213] <Example 1>

[0214] A solution containing a polysilsesquioxane having a cage-like silsesquioxane is prepared using the following method. It should be noted that for aspects not described below, reference can be made to the methods described in Japanese Patent Application Publication No. 2015-155541 and International Publication No. 2004 / 024741.

[0215] In a flask equipped with a reflux condenser, phenyltrimethoxysilane (1 equivalent), 2-propanol, pure water (1.2 equivalent), and sodium hydroxide (0.5 equivalent) were added, and the mixture was stirred under reflux for 5 hours. Then, it was stirred overnight at room temperature. After stirring, pure water was added to the flask, and the reaction was stopped. Next, a water washing operation was performed, i.e., stirring was carried out while pure water was added, and then the aqueous layer was removed. Then, the liquid in the flask was separated into a white solid using a 0.1 μm membrane filter, thereby obtaining the white solid as the crude product.

[0216] Next, the crude product (1 equivalent), trichloromethylsilane (2 equivalents), and toluene (enough to dissolve the solute) were added to a flask equipped with a dropping funnel, and the mixture was stirred to obtain a mixture. This mixture was then mixed with triethylamine (4 equivalents) while stirring, and the stirring continued for 2 hours. After stirring, pure water was added to the flask, and the reaction was stopped. Next, a water washing operation was performed, i.e., stirring was carried out while pure water was added, and then the aqueous layer was removed. Then, the solvent (toluene) was removed from the liquid in the flask by distillation using an evaporator, thereby obtaining a cage-like silsesquioxane. The synthetic reaction formula for the cage-like silsesquioxane is shown below.

[0217] [Chemistry 23]

[0218]

[0219] Next, tetrahydrofuran (enough to dissolve the solute), triethylamine (2 equivalents), and the aforementioned cage-like silsesquioxane (1 equivalent) were added to a flask equipped with a dropping funnel, and then stirred to obtain a mixture. The flask was cooled in an ice bath, and 1,7-dichlorooctamethyltetrasiloxane (1 equivalent) was added dropwise to the flask while stirring the mixture, and stirring continued for 2 hours after the addition. Then, the mixture was stirred overnight at room temperature. After stirring, pure water was added to the flask, and the reaction was stopped. Then, the following water washing operation was performed several times: stirring while adding pure water, and then removing the aqueous layer. Then, the solvent (tetrahydrofuran) in the liquid in the flask was removed by distillation using an evaporator, thereby obtaining a solid.

[0220] A solution (polysiloxane solution) containing a polysiloxane as shown in the following formula is prepared by mixing the obtained solid with anisole at a polymer concentration of 50% by mass. The polysiloxane has a cage-like silsesquioxane structure as a structural unit.

[0221] [Chemistry 24]

[0222]

[0223] The weight-average molecular weight of this polysiloxane solution, determined by gel permeation chromatography (GPC), is 36,000.

[0224] The protective film is made as follows.

[0225] The above-mentioned polysiloxane solution was spin-coated onto a quartz glass substrate at 1500 rpm, thereby obtaining a polysiloxane film on the substrate. The film on the substrate was dried on a hot plate at 80°C for 2 hours to remove the solvent. Then, the film was peeled off from the substrate by adhesive tape to obtain a protective film of polysiloxane with a cage-like silsesquioxane structure. The thickness of the obtained protective film was 6.0 μm.

[0226] Alternatively, the obtained protective film can be unfolded and then adhered to the frame, thereby enabling the fabrication of a protective film assembly.

[0227] <Example 2>

[0228] By replacing phenyltrimethoxysilane with trimethoxymethylsilane, and otherwise using the same method as in Example 1, a polysiloxane solution containing a polysiloxane having a cage-like silsesquioxane structure (hereinafter referred to as the polysiloxane of Example 2) was prepared. The polysiloxane of Example 2 is a polysiloxane having a cage-like silsesquioxane structure as a structural unit, as shown in the following formula.

[0229] [Chemistry 25]

[0230]

[0231] The weight-average molecular weight of this polysiloxane solution, as determined by gel permeation chromatography (GPC), is 35,000.

[0232] The protective film was prepared using the same method as in Example 1. The resulting protective film had a thickness of 6.0 μm.

[0233] In addition, the obtained protective film is unfolded and then glued to the frame to create a protective film assembly.

[0234] <Example 3>

[0235] A cage-like silsesquioxane was obtained by replacing phenyltrimethoxysilane with trimethoxymethylsilane, and the reaction between the cage-like silsesquioxane and 1,7-dichlorooctamethyltetrasiloxane was not carried out. Otherwise, a polysiloxane solution containing a polysiloxane having a cage-like silsesquioxane structure (hereinafter referred to as the polysiloxane of Example 3) was prepared using the same method as in Example 1. The polysiloxane of Example 3 is a polysiloxane having a cage-like silsesquioxane structure as a structural unit, as shown in the following formula.

[0236] [Chemistry 26]

[0237]

[0238] The weight-average molecular weight of this polysiloxane solution, as determined by gel permeation chromatography (GPC), is 33,000.

[0239] The protective film was prepared using the same method as in Example 1. The resulting protective film had a thickness of 6.0 μm.

[0240] In addition, the obtained protective film is unfolded and adhered to the frame to create a protective film assembly.

[0241] <Example 4>

[0242] A polysilsesquioxane solution containing cage-like silsesquioxanes is prepared according to a known method (International Publication 2018 / 101213) as follows.

[0243] In an argon atmosphere and under ice bath conditions, a solution of i-Bu-substituted cyclic silanol (5.0 g, 0.010 mol) in diethyl ether (200 mL) was added dropwise to a solution of trichlorosilane (17 mL, 0.094 mol) and triethylamine (13 mL) in diethyl ether (200 mL). The mixture was then stirred at room temperature for one day, and the solvent was removed by distillation under reduced pressure. Next, hexane (200 mL) was added, and the mixture was filtered under argon atmosphere to remove the salt. Finally, the hexane was removed to obtain the dichlorosiloxy form of the cyclic silanol.

[0244] Diethyl ether (200 ml) was added to the dichlorosiloxy group of the cyclic silanol, and the solution was added dropwise to a mixture of acetone (400 ml) and water (50 ml) under ice bath conditions. After the addition was complete, the mixture was stirred at room temperature for 2 days, and then stirred under reflux for 1 day. After removing the solvent using a rotary evaporator, the mixture was separated using diethyl ether and saturated saline. The crude product was separated by size exclusion chromatography and wet silica gel chromatography to obtain the target compound with hydrogen atoms as substituents.

[0245] [Chemistry 27]

[0246]

[0247] The compound (1 g) obtained by the reaction shown in formula (1) above was dissolved in 10 ml of toluene, and dimethoxydimethylsilane (0.5 g) was added. While cooling to below 5 °C, tris(pentafluorophenyl)borane (10 mg) was added, and the mixture was stirred at room temperature for 5 hours. The crude product was filtered and concentrated to obtain the target compound.

[0248] [Chemistry 28]

[0249]

[0250] Using the compound obtained by the reaction shown in formula (2) above, a polysiloxane solution containing a polysiloxane having a cage-like silsesquioxane structure was prepared by the same method as in Example 1. The weight-average molecular weight of this polysiloxane solution was 35,000, as determined by gel permeation chromatography (GPC).

[0251] The protective film was prepared using the same method as in Example 1. The resulting protective film had a thickness of 6.0 μm.

[0252] In addition, the obtained protective film is unfolded and adhered to the frame to create a protective film assembly.

[0253] (Comparative Example 1: Protective film made of fluoropolymer resin)

[0254] The protective film was obtained by using a solution of fluoropolymer (manufactured by AGC Corporation, CYTOP CTX-809SP2) diluted with a fluorinated solvent (manufactured by AGC Corporation, CYTOP CT-SLV) instead of the polysiloxane solution in Example 1, except that the procedure was the same as in Example 1. The thickness of the obtained protective film was 0.3 μm.

[0255] (Comparative Example 2: Protective film made of cellulose)

[0256] A solution of ethyl lactate in cellulose acetate propionate (CAP4 80-20, manufactured by Eastman Chemical Company) was used instead of the polysiloxane solution in Example 1. Otherwise, the procedure was the same as in Example 1 to obtain the protective film. The resulting protective film had a thickness of 3.8 μm.

[0257] (Comparative Example 3: Protective film made of polytrapezoidal siloxane)

[0258] The protective film was obtained by replacing the polysiloxane solution of Example 1 with a polyladled siloxane solution prepared according to a known method (Japanese Patent Application Laid-Open No. 4-166840), except that the procedure was the same as in Example 1. The thickness of the obtained protective film was 3.0 μm.

[0259] [Measurement and Evaluation]

[0260] <Transmittance Measurement Experiment>

[0261] Using a UV-Vis spectrophotometer (UV-1900i, manufactured by Shimadzu Corporation), the transmittance (%) of light with wavelengths of 190 nm or higher and 440 nm or lower was measured for the protective films of the Examples and Comparative Examples. In this example, the average transmittance (%) was calculated for the respective ranges of 290 nm or higher and 385 nm or lower, 360 nm or higher and 440 nm or lower, 248 nm, and 193 nm. The results are shown in the table below.

[0262] <Exposure Test>

[0263] The protective films of the examples and comparative examples were adhered to an aluminum frame (inner diameter 24×29mm, outer diameter 35×40mm) to obtain test pieces. The obtained test pieces were irradiated with VUV light according to the conditions in the table below, with an irradiation distance of 69mm or 9mm and an irradiation time of 30 seconds or 1 minute.

[0264] In addition, the irradiation conditions for VUV light are as follows.

[0265] (irradiation conditions)

[0266] • Light source: Xe

[0267] Illuminance: 50mW / cm² 2

[0268] • Oxygen concentration: 1000 ppm

[0269] <Puncture Test>

[0270] The protective film after the above <exposure test> was adhered to an aluminum frame with a 7mm diameter circular hole, covering the hole, using double-sided tape to obtain a test piece. Once a test piece was obtained, a tensile testing machine was used to apply a load to it until the protective film broke. The load (gf; maximum test force) at which the protective film broke was then calculated. The maximum test force was calculated on a trial basis (n=4), and the average values ​​are shown in the table below.

[0271] It should be noted that the calculation of the maximum test force is carried out according to the following apparatus and conditions.

[0272] (Apparatus and Conditions)

[0273] ·Device name: Autograph (SHIMAZU EZ-S manufactured by Shimadzu Corporation)

[0274] Force sensor: 10N

[0275] • Crosshead speed: 5mm / min

[0276] Temperature: 21℃

[0277] Humidity: 50%

[0278] The results of the above measurements and evaluations are shown in the table below.

[0279] In the table, "This refers to a situation where the protective membrane breaks during the preparation of the test piece for the puncture test, making it impossible to determine the result."

[0280] [Table 1]

[0281]

[0282] As can be confirmed from the table above, according to the embodiments, a protective film can be provided that exhibits excellent transmittance to light with a wavelength suitable for photolithography, and can ensure mechanical strength and / or light resistance.

[0283] Furthermore, according to the embodiments, it has been confirmed that photolithography using j-line (313nm), i-line (365nm) and h-line (405nm), and using their ultraviolet light, is suitable. Therefore, it is expected to be able to meet the requirements of next-generation electronic devices, such as the requirement for further miniaturization of patterns.

[0284] Industrial utilization potential

[0285] As one aspect of the present invention, the protective film and protective film assembly are suitable for dust prevention in photolithography processes used to form semiconductors, LSIs, thin-film transistors (TFTs) constituting flat panel displays (FPDs), etc. It is suitable for photolithography methods utilizing j-lines (313nm), i-lines (365nm), and h-lines (405nm), and using their ultraviolet light as an exposure source.

[0286] Explanation of reference numerals in the attached figures

[0287] 1: Protective membrane assembly

[0288] 2: Frame

[0289] 2a: Long side

[0290] 2b: Short side

[0291] 3: Protective film

[0292] 4: Vent hole

[0293] 5: Filter

[0294] 6: Membrane adhesive layer

[0295] 7: Mask adhesive layer

[0296] Op: Opening.

Claims

1. A protective film comprising a polysiloxane having a cage-like silsesquioxane structure.

2. The protective film according to claim 1, wherein, The polysiloxane has at least one structure selected from the group consisting of the structure shown in formula (i), the structure shown in formula (ii), and the structure shown in formula (iii). [Chemistry 1] In equation (i), R 11 and R 12 Each of the following groups independently represents a siloxy group (-OSi), a hydrocarbon group with 1 to 12 carbon atoms, a hydrogen atom (-H), a hydroxyl group (-OH), or a fluorine group (-F) constituting the polysiloxane; wherein, in formula (i), there are a total of 4 R groups. 11 And a total of 4 R 12 At least two of them represent the siloxy groups that constitute the polysiloxane, namely -OSi. [Chemistry 2] In equation (ii), R 21 and R 22 Each of the following groups independently represents a hydrocarbon group (-H), a hydrogen atom (-H), a hydroxyl group (-OH), or a fluorine group (-F), representing 1 to 12 carbon atoms respectively. 23 and R 24 Each of the following groups independently represents a siloxy group (-OSi), a hydrocarbon group with 1 to 12 carbon atoms, a hydrogen atom (-H), a hydroxyl group (-OH), or a fluorine group (-F) constituting the polysiloxane; wherein, in formula (ii), there are a total of 2 R groups. 23 And a total of 2 R 24 At least two of them are siloxy groups, i.e., -OSi, constituting the polysiloxane. [Chemistry 3] In equation (iii), R 31 and R 32 Each of the following groups independently represents a siloxy group (-OSi), a hydrocarbon group with 1 to 12 carbon atoms, a hydrogen atom (-H), a hydroxyl group (-OH), or a fluorine group (-F) constituting the polysiloxane; wherein, there are a total of 5 R groups in formula (iii). 31 And a total of 5 R 32 At least two of them are siloxy groups that constitute the polysiloxane, namely -OSi.

3. The protective film according to claim 1 or 2, wherein, The polysiloxane has at least one structure selected from the group consisting of the structure shown in formula (I-1), the structure shown in formula (II-1), and the structure shown in formula (III-1). [Chemistry 4] In equation (I-1), R 11 R 12 and R 41 Each of these groups independently represents a hydrocarbon group (1-12 carbon atoms), a hydrogen atom (-H), a hydroxyl group (-OH), or a fluorine group (-F), and n represents an integer from 1 to 30. [Chemistry 5] In equation (II-1), R 21 R 22 R 23 and R 41 Each of these groups independently represents a hydrocarbon group (1-12 carbon atoms), a hydrogen atom (-H), a hydroxyl group (-OH), or a fluorine group (-F), and n represents an integer from 1 to 30. [Chemistry 6] In equation (III-1), R 31 R 32 and R 41 Each of the following groups can be independently represented: a hydrocarbon group with 1 to 12 carbon atoms, a hydrogen atom (-H), a hydroxyl group (-OH), or a fluorine group (-F), and n can be an integer from 1 to 30.

4. The protective film according to claim 3, wherein, In the polysiloxane, the proportion of structural units from the structures shown in formulas (i) to (iii) is 50% by mass or more, and / or the proportion of the structures shown in formulas (I-1) to (III-1) is 50% by mass or more.

5. A protective film assembly comprising a frame and a protective film adhered to the frame, wherein the protective film is the protective film according to claim 1 or 2.

6. A formulation for making a protective film, comprising a polysiloxane having a cage-like silsesquioxane structure.

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