Hollow structure, photosensitive composition, method of producing photosensitive composition, and method of inspecting photosensitive composition

Abstract

To provide a hollow structure in which outgassing is suppressed, a photosensitive composition useful for preparing the same, and the like.SOLUTION: A hollow structure 300 includes: a device substrate 100 including a substrate 10, a comb-shaped electrode 20, and a SiN layer 30; a side wall 210 formed to surround the comb-shaped electrode 20; and a top plate part 220 formed to face the device substrate 100. At least one of the side wall 210 and the top plate part 220 is formed by curing a photosensitive composition. When the top of the SiN layer 30 is evaluated by X-ray photoelectron spectroscopy, a ratio (C / Si) of carbon to Si is less than 0.2, and a detection amount of fluorine is equal to or less than 0.3 atm%. A photosensitive composition, in which, when the top of a SiN layer is evaluated by X-ray photoelectron spectroscopy in a specific [outgassing evaluation method], C / Si is less than 0.2 and a detection amount of fluorine is equal to or less than 0.3 atm%, is employed for preparing the hollow structure 300.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a hollow structure, a photosensitive composition, a method for producing a photosensitive composition, and a method for inspecting a photosensitive composition. [Background technology]

[0002] In recent years, the development of microelectronic devices such as surface acoustic wave (SAW) filters has progressed. The packages that encapsulate such electronic devices have a hollow structure to ensure the propagation of surface acoustic waves and the mobility of the moving parts of the electronic devices. A photosensitive composition is used to form the hollow structure, and the package is manufactured by molding the substrate on which the interdigital electrodes are formed while maintaining the hollow structure.

[0003] For example, Patent Document 1 discloses a hollow structure having a hollow portion consisting of a substrate having aluminum wiring, a sidewall provided on the upper part of the substrate so as to surround the aluminum wiring, and a top plate provided in contact with the upper surface of the sidewall and covering the upper part of the substrate, and a method for manufacturing the hollow structure.

[0004] The hollow structure is fabricated as follows. A photosensitive resin film formed using a photosensitive composition is laminated onto a support having an aluminum layer formed on a substrate, and a pattern is formed by selective exposure, post-exposure baking, and development, followed by a heat treatment to produce a sidewall. Next, another photosensitive resin film is laminated onto the support on which the sidewall has been formed, and a top plate is produced by selective exposure, post-exposure baking, development, and hard baking (curing) treatment, thereby producing a hollow structure with a hollow portion.

[0005] Incidentally, it is generally said that in an electric circuit that transmits information, if the weight of the electrodes increases due to corrosion or the like, the frequency shifts to the negative side (see Non-Patent Document 1). [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2022-81312 [Non-patent literature]

[0007] [Non-Patent Document 1] Micro-corrosion measurement using QCM and SAW; Boshoku Gijutsu 39,697-708(1990) Summary of the Invention [Problem to be solved by the invention]

[0008] However, as described above, when a hollow structure is produced using a photosensitive composition, gas (outgassing) derived from the photosensitive composition is generated during the thermal curing process (post-exposure bake, cure) after exposure. Furthermore, when outgassing components derived from the photosensitive composition adhere to the interdigital electrodes, a frequency shift to the negative side occurs in the microelectronic device, causing noise to be picked up.

[0009] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a hollow structure in which outgassing is suppressed, a photosensitive composition useful for producing the hollow structure, a method for producing the photosensitive composition, and a method for inspecting the photosensitive composition. [Means for solving the problem]

[0010] In order to solve the above problems, the present invention employs the following configuration.

[0011] That is, a first aspect of the present invention is a hollow structure comprising a device substrate including a substrate, a comb-shaped electrode provided on the substrate, and a SiN layer formed on the substrate so as to cover the comb-shaped electrode, side walls formed on the device substrate so as to surround the comb-shaped electrode, and a top plate portion formed on the side walls so as to face the device substrate, wherein at least one of the side walls and the top plate portion is made of a cured photosensitive composition, and when the SiN layer is evaluated by X-ray photoelectron spectroscopy, the hollow structure shows a carbon to silicon ratio (C / Si) of less than 0.2 and a detected amount of fluorine of 0.3 atm% or less.

[0012] A second aspect of the present invention is a photosensitive composition for producing the hollow structure according to the first aspect, wherein the photosensitive composition is a material for at least one of the sidewalls and the top plate portion, and when evaluated on a SiN layer of a Si substrate by X-ray photoelectron spectroscopy in the "Method for evaluating outgassing" described below, the photosensitive composition exhibits a carbon to silicon ratio (C / Si) of less than 0.2 and a detected amount of fluorine of 0.3 atm% or less.

[0013] [Outgassing evaluation method] Step (1-1): A photosensitive composition dissolved in methyl ethyl ketone to adjust the solid content to 75% by mass is applied onto a release polyethylene terephthalate (PET) film using an applicator, and the film is dried in an oven at 70°C for 10 minutes to form a photosensitive composition layer with a thickness of 20 μm. Step (1-2): Next, the photosensitive composition layer is attached to the Si substrate so that the photosensitive composition layer and the Si substrate are in contact with each other, using a laminator under the following conditions: 80°C, pressure 0.3 MPa, and speed 0.5 m / min. Step (1-3): Next, the release PET film is peeled off, and then the photosensitive composition layer is exposed using a ghi broadband exposure machine to obtain a test substrate. Step (2): Separately, on a Si substrate having a SiN layer on the outermost surface, a 50 μm thick polyimide film with a heat resistance of 300°C or higher, with the center cut out, is placed on the outer peripheral edge of the SiN layer on the Si substrate. Step (3): Next, the test substrate is placed on the polyimide film so that the photosensitive composition layer and the SiN layer face each other. Step (4): Next, the substrate is baked. The baking conditions are as follows: the substrate is heated on a hot plate at 90°C for 5 minutes, then heated to 200°C over 15 minutes, and held at 200°C for 1 hour. The substrate is then removed from the hot plate and allowed to cool. Step (5): After cooling, the test substrate and the polyimide film are removed, and then the portion of the SiN layer that was facing the photosensitive composition layer but is not in contact with the polyimide film is evaluated by X-ray photoelectron spectroscopy. Step (6): Using an X-ray photoelectron spectrometer, the composition ratios of C / Si and F are calculated from the spectra of C1s for carbon (C), Si2p for silicon (Si), and F1s for fluorine (F).

[0014] A third aspect of the present invention is a method for producing a photosensitive composition for producing a hollow structure including a device substrate including a substrate, comb-shaped electrodes provided on the substrate, and a SiN layer formed on the substrate so as to cover the comb-shaped electrodes; side walls formed on the device substrate so as to surround the comb-shaped electrodes; and a top plate portion formed on the side walls so as to face the device substrate, wherein the photosensitive composition is a material for at least one of the side walls and the top plate portion, and the method includes a step of selecting photosensitive compositions that have a carbon to silicon ratio (C / Si) of less than 0.2 and a detected amount of fluorine of 0.3 atm% or less when the SiN layer of the Si substrate is evaluated by X-ray photoelectron spectroscopy according to the "Method for evaluating outgassing" described below.

[0015] [Outgassing evaluation method] Step (1-1'): A photosensitive composition is applied onto a release polyethylene terephthalate (PET) film using an applicator, and then dried in an oven at 70°C for 10 minutes to form a photosensitive composition layer with a thickness of 20 μm. Step (1-2): Next, the photosensitive composition layer is attached to the Si substrate so that the photosensitive composition layer and the Si substrate are in contact with each other, using a laminator under the following conditions: 80°C, pressure 0.3 MPa, and speed 0.5 m / min. Step (1-3): Next, the release PET film is peeled off, and then the photosensitive composition layer is exposed using a ghi broadband exposure machine to obtain a test substrate. Step (2): Separately, on a Si substrate having a SiN layer on the outermost surface, a 50 μm thick polyimide film with a heat resistance of 300°C or higher, with the center cut out, is placed on the outer peripheral edge of the SiN layer on the Si substrate. Step (3): Next, the test substrate is placed on the polyimide film so that the photosensitive composition layer and the SiN layer face each other. Step (4): Next, the substrate is baked. The baking conditions are as follows: the substrate is heated on a hot plate at 90°C for 5 minutes, then heated to 200°C over 15 minutes, and held at 200°C for 1 hour. The substrate is then removed from the hot plate and allowed to cool. Step (5): After cooling, the test substrate and the polyimide film are removed, and then the portion of the SiN layer that was facing the photosensitive composition layer but is not in contact with the polyimide film is evaluated by X-ray photoelectron spectroscopy. Step (6): Using an X-ray photoelectron spectrometer, the composition ratios of C / Si and F are calculated from the spectra of C1s for carbon (C), Si2p for silicon (Si), and F1s for fluorine (F).

[0016] A fourth aspect of the present invention is a method for inspecting a photosensitive composition for producing a hollow structure including a device substrate including a substrate, a comb-shaped electrode provided on the substrate, and a SiN layer formed on the substrate so as to cover the comb-shaped electrode, side walls formed on the device substrate so as to surround the comb-shaped electrode, and a top plate portion formed on the side walls so as to face the device substrate, wherein the photosensitive composition is a material for at least one of the side walls and the top plate portion, and the carbon to silicon ratio (C / Si) and the amount of fluorine detected on the SiN layer provided on the Si substrate are evaluated by X-ray photoelectron spectroscopy in the "Method for evaluating outgassing" described below.

[0017] [Outgassing evaluation method] Procedure (1-1"): A photosensitive composition is applied onto a release polyethylene terephthalate (PET) film using an applicator, and dried in an oven at 70°C for 10 minutes to form a photosensitive composition layer with a thickness of 20 μm. Step (1-2): Next, the photosensitive composition layer is attached to the Si substrate so that the photosensitive composition layer and the Si substrate are in contact with each other, using a laminator under the following conditions: 80°C, pressure 0.3 MPa, and speed 0.5 m / min. Step (1-3): Next, the release PET film is peeled off, and then the photosensitive composition layer is exposed using a ghi broadband exposure machine to obtain a test substrate. Step (2): Separately, on a Si substrate having a SiN layer on the outermost surface, a 50 μm thick polyimide film with a heat resistance of 300°C or higher, with the center cut out, is placed on the outer peripheral edge of the SiN layer on the Si substrate. Step (3): Next, the test substrate is placed on the polyimide film so that the photosensitive composition layer and the SiN layer face each other. Step (4): Next, the substrate is baked. The baking conditions are as follows: the substrate is heated on a hot plate at 90°C for 5 minutes, then heated to 200°C over 15 minutes, and held at 200°C for 1 hour. The substrate is then removed from the hot plate and allowed to cool. Step (5): After cooling, the test substrate and the polyimide film are removed, and then the portion of the SiN layer that was facing the photosensitive composition layer but is not in contact with the polyimide film is evaluated by X-ray photoelectron spectroscopy. Step (6): Using an X-ray photoelectron spectrometer, the composition ratios of C / Si and F are calculated from the spectra of C1s for carbon (C), Si2p for silicon (Si), and F1s for fluorine (F). [Effects of the Invention]

[0018] According to the present invention, it is possible to provide a hollow structure in which outgassing is suppressed, a photosensitive composition useful for producing the hollow structure, a method for producing the photosensitive composition, and a method for inspecting the photosensitive composition. [Brief explanation of the drawings]

[0019] [Figure 1] FIG. 1 is a cross-sectional view showing an embodiment of a hollow structure. [Figure 2A] FIG. 1 is a schematic diagram illustrating steps (1-1) and (1-2) of the [method for evaluating outgassing]. [Figure 2B] FIG. 1 is a schematic diagram illustrating step (1-3) of the [method for evaluating outgassing]. [Figure 3] FIG. 1 is a schematic diagram illustrating step (2) of the [method for evaluating outgassing]. [Figure 4] FIG. 1 is a schematic diagram illustrating step (3) of the [method for evaluating outgassing]. [Figure 5] FIG. 1 is a schematic diagram illustrating step (4) of the [method for evaluating outgassing]. [Figure 6] FIG. 1 is a GPC chart of a bisphenol A novolac epoxy resin before purification. [Figure 7] FIG. 2 is a GPC chart of a purified bisphenol A novolac epoxy resin. DETAILED DESCRIPTION OF THE INVENTION

[0020] In this specification and claims, the term "aliphatic" is a relative concept to aromatic, and is defined to mean a group or compound that does not have aromaticity. Unless otherwise specified, the term "alkyl group" includes linear, branched, and cyclic monovalent saturated hydrocarbon groups. The same applies to alkyl groups in alkoxy groups. Unless otherwise specified, the term "alkylene group" includes linear, branched and cyclic divalent saturated hydrocarbon groups. A "halogenated alkyl group" is an alkyl group in which some or all of the hydrogen atoms have been substituted with halogen atoms, and examples of the halogen atoms include fluorine, chlorine, bromine, and iodine atoms. The term "fluorinated alkyl group" refers to an alkyl group in which some or all of the hydrogen atoms have been substituted with fluorine atoms. The term "structural unit" refers to a monomer unit that constitutes a polymeric compound (resin, polymer, copolymer). The phrase "optionally substituted" includes both cases where a hydrogen atom (-H) is replaced with a monovalent group and where a methylene group (-CH2-) is replaced with a divalent group. The term "exposure" is a general concept that includes irradiation with radiation.

[0021] (Hollow structure) A hollow structure according to one embodiment of the present invention comprises a device substrate having a substrate, a comb-shaped electrode provided on the substrate, and a SiN layer formed on the substrate so as to cover the comb-shaped electrode, a sidewall formed on the device substrate so as to surround the comb-shaped electrode, and a top plate portion formed on the sidewall so as to face the device substrate. In the hollow structure according to this embodiment, at least one of the sidewall and the top plate is formed by curing a photosensitive composition, and when the SiN layer is evaluated by X-ray photoelectron spectroscopy, the carbon to silicon ratio (C / Si) is less than 0.2 and the detected amount of fluorine is 0.3 atm% or less.

[0022] FIG. 1 is a cross-sectional view showing one embodiment of a hollow structure. In the drawings, components may be shown schematically to make them easier to see, and some components may be shown on different scales. In FIG. 1, a hollow structural body 300 is composed of a device substrate 100 and a cured body 200 . The device substrate 100 includes a substrate 10 , a comb-shaped electrode 20 provided on the substrate 10 , and a SiN layer 30 formed on one surface of the substrate 10 so as to cover the comb-shaped electrode 20 . The cured body 200 is made of a cured photosensitive composition, and the photosensitive composition forming the side wall 210 and the photosensitive composition forming the top plate portion 220 are integrated by curing. The sidewall 210 is formed on the device substrate 100 including the SiN layer 30 so as to surround the interdigital electrode 20. The top plate portion 220 is formed on the upper surface of the sidewall 210 so as to face the SiN layer 30, i.e., so as to face the device substrate 100 including the SiN layer 30. In Fig. 1, the dotted line between the sidewall 210 and the top plate portion 220 indicates a virtual interface. In the hollow structure 300, the comb-shaped electrode 20 is disposed in a hollow, sealed space surrounded by the device substrate 100 and the cured body 200.

[0023] When the hollow structure 300 is evaluated on the SiN layer 30 of the device substrate 100 by X-ray photoelectron spectroscopy, the carbon to silicon ratio (C / Si) is less than 0.2 and the detected amount of fluorine is 0.3 atm% or less. In this way, a hollow structure having a C / Si ratio of less than 0.2 and a detected amount of fluorine of 0.3 atm% or less suppresses outgassing within the hollow, sealed space, and in a microelectronic device using this hollow structure, a frequency shift to the negative side is unlikely to occur.

[0024] The SiN layer of the device substrate is evaluated by X-ray photoelectron spectroscopy (XPS) as follows. The surface of the SiN layer exposed in the hollow sealed space in the hollow structure is measured by XPS using an X-ray photoelectron spectroscopy device. From the XPS measurements, the carbon (C) C1s spectrum, silicon (Si) Si2p spectrum, and fluorine (F) F1s spectrum are used to calculate the ratio of carbon to silicon (C / Si) and the composition ratio of F, and the detected amounts of C / Si and fluorine [atm%] are then determined. As the X-ray photoelectron spectrometer, for example, a K-Alpha X-ray photoelectron spectrometer system manufactured by Thermo Fisher Scientific can be used.

[0025] The presence or absence of outgassing in the hollow sealed space of the hollow structure can be evaluated by the contact angle on the SiN layer, which serves as an alternative index for the change in weight on the SiN layer before and after the outgassing. A hollow structure in which the contact angle on the SiN layer is preferably less than 50° suppresses the generation of outgassing within the hollow, sealed space, and in a microelectronic device using this hollow structure, a frequency shift to the negative side is unlikely to occur.

[0026] The presence or absence of outgassing based on the contact angle of the SiN layer is evaluated by using a contact angle meter to measure the contact angle when water is dropped onto the surface of the SiN layer exposed to the hollow, sealed space in the hollow structure. As the contact angle meter, for example, DMo-501 manufactured by Kyowa Interface Science Co., Ltd. can be used.

[0027] In the above description of the hollow structural body, both the side wall 210 and the top plate 220 are formed from a cured photosensitive composition, but this is not limited thereto, and only one of the side wall 210 and the top plate 220 may be formed from a cured photosensitive composition. That is, both the side wall and the top plate constituting the hollow structural body may be formed from a cured photosensitive composition, or either the side wall or the top plate may be formed from a cured photosensitive composition.

[0028] Regarding the photosensitive composition: In the hollow structure of this embodiment, the carbon to silicon ratio (C / Si) on the SiN layer of the device substrate, the amount of fluorine detected, and the contact angle can be controlled by selecting the composition (constituent components, content) of the photosensitive composition that forms at least one of the side wall and the top plate portion. In the hollow structural body of this embodiment, the photosensitive composition used in at least one of the side wall and the top plate portion may contain an epoxy group-containing compound and a cationic polymerization initiator. A preferred photosensitive composition contains an epoxy group-containing compound and a cationic polymerization initiator, and the cationic polymerization initiator contains a compound consisting of an anion moiety containing a borate anion and a cation moiety. Alternatively, a preferred photosensitive composition contains an epoxy group-containing compound and a cationic polymerization initiator, in which the epoxy group-containing compound includes a tri- or higher functional epoxy group-containing compound, and the content of a bifunctional epoxy monomer is 2 mass% or less based on the total mass of the tri- or higher functional epoxy group-containing compound and the bifunctional epoxy monomer. A more preferred photosensitive composition contains an epoxy group-containing compound and a cationic polymerization initiator, wherein the epoxy group-containing compound includes a tri- or higher functional epoxy group-containing compound, and the content of a bifunctional epoxy monomer is 2 mass% or less based on the total mass of the tri- or higher functional epoxy group-containing compound and the bifunctional epoxy monomer, and the cationic polymerization initiator includes a compound consisting of an anion moiety containing a borate anion and a cation moiety. The epoxy group-containing compound, cationic polymerization initiator, and preferable photosensitive composition are the same as those described later in the section (Photosensitive composition).

[0029] (Photosensitive composition) The photosensitive composition according to one embodiment of the present invention is used to produce the hollow structure according to the above-described embodiment. The photosensitive composition according to this embodiment is a material for at least one of the side walls and the top plate that constitute the hollow structural body. In addition, when the photosensitive composition according to this embodiment is evaluated on a SiN layer of a Si substrate by X-ray photoelectron spectroscopy according to the following [Method for evaluating outgassing], the ratio of carbon to silicon (C / Si) is less than 0.2 and the detected amount of fluorine is 0.3 atm% or less.

[0030] [Outgassing evaluation method] One embodiment of the outgassing evaluation method is a method in which the following steps (1-1), (1-2), (1-3), (2), (3), (4), (5), and (6) are performed in this order. 2A to 5 are schematic diagrams illustrating steps (1-1) to (4) of one embodiment of the outgassing evaluation method.

[0031] Regarding step (1-1): A photosensitive composition dissolved in methyl ethyl ketone to adjust the solid content to 75% by mass is applied onto a release polyethylene terephthalate (PET) film (not shown) using an applicator, and dried in an oven at 70°C for 10 minutes to form a photosensitive composition layer 60 with a thickness of 20 μm. The term "solid content" as used herein refers to the components constituting the photosensitive composition excluding the solvent. The components that the photosensitive composition may contain, the contents thereof, and the like will be described in detail later.

[0032] Regarding steps (1-2): Next, the photosensitive composition layer 60 formed on a release PET film (not shown) is attached to the Si substrate 50 so that the photosensitive composition layer 60 is in contact with the Si substrate 50. The attachment conditions are set to 80°C, a pressure of 0.3 MPa, and 0.5 m / min using a laminator (FIG. 2A).

[0033] Regarding steps (1-3): Next, the release PET film (not shown) is peeled off, and then the photosensitive composition layer 60 attached to the Si substrate 50 is exposed using a ghi broadband exposure machine to obtain a test substrate 70 consisting of a laminate of the exposed photosensitive composition layer 60E and the Si substrate 50 (Figure 2B). The exposure of the photosensitive composition layer 60 is preferably carried out by appropriately controlling the exposure amount depending on the composition of the photosensitive composition. For example, the exposure amount is 10 mJ / cm 2 2 More than 2000mJ / cm 2 It is preferable to perform the following exposure.

[0034] Regarding step (2): Separately, on a Si substrate 80 having a SiN layer 83 on the outermost surface, a 50 μm thick polyimide film 90 with a heat resistance of 300°C or higher and cut out at the center is placed on the outer peripheral edge of the SiN layer 83 on the Si substrate 80 (Figure 3).

[0035] A 50 μm thick film having heat resistance of 300° C. or higher is used as the polyimide film 90. Here, the polyimide film 90 is assumed to be a side wall of the hollow structure. Because the polyimide film 90 has heat resistance of 300° C. or higher, it does not decompose or generate outgassing when heated to 200° C. in step (4) described below.

[0036] An example of the polyimide film 90 is a film made of polyimide having a repeating structure represented by the following chemical formula (PI-1).

[0037] [ka]

[0038] For the polyimide film 90, a commercially available product such as Kapton (registered trademark) (heat resistant temperature 300° C.) manufactured by DuPont-Toray Co., Ltd. can be used.

[0039] Regarding step (3): Next, the test substrate 70 is placed on the polyimide film 90 so that the exposed photosensitive composition layer 60E faces the SiN layer 83 of the Si substrate 80. This forms a hollow, sealed space surrounded by the Si substrate 80 having the SiN layer 83 on its outermost surface, the polyimide film 90, and the test substrate 70 (FIG. 4).

[0040] Regarding step (4): Next, the substrate is baked by heating it on a hot plate 40 at 90°C for 5 minutes, then increasing the temperature to 200°C over 15 minutes, and holding it at 200°C for 1 hour (FIG. 5).Then, the substrate is removed from the hot plate 40 and allowed to cool.

[0041] Regarding step (5): After cooling, the test substrate 70 and the polyimide film 90 are removed. Thereafter, a portion 85 of the SiN layer 83 that was facing the exposed photosensitive composition layer 60E and that is not in contact with the polyimide film 90 is evaluated by X-ray photoelectron spectroscopy.

[0042] Regarding step (6): Using an X-ray photoelectron spectrometer, the composition ratios of C / Si and F in the region 85 on the SiN layer 83 that is not in contact with the polyimide film 90 are calculated from the spectra of C1s for carbon (C), Si2p for silicon (Si), and F1s for fluorine (F).

[0043] In an embodiment of the photosensitive composition, when the SiN layer of a Si substrate is evaluated by X-ray photoelectron spectroscopy using the above-described series of steps (1-1), (1-2), (1-3), (2), (3), (4), (5), and (6) in the "method for evaluating outgassing," the carbon-to-silicon ratio (C / Si) is less than 0.2 and the detected amount of fluorine is 0.3 atm% or less. When this photosensitive composition is used to fabricate a hollow structure, outgassing originating from the photosensitive composition is suppressed during the post-exposure thermal curing process (post-exposure bake, cure). Microelectronic devices using hollow structures fabricated with this photosensitive composition are less likely to experience a negative frequency shift.

[0044] The evaluation of the SiN layer 83 by X-ray photoelectron spectroscopy (XPS) is carried out as follows. A portion 85 on the SiN layer 83 that was facing the photosensitive composition layer 60E after exposure and that is not in contact with the polyimide film 90 is measured by XPS using an X-ray photoelectron spectrometer. From the XPS measurements, the carbon (C) C1s spectrum, silicon (Si) Si2p spectrum, and fluorine (F) F1s spectrum are used to calculate the ratio of carbon to silicon (C / Si) and the composition ratio of F, and the detected amounts of C / Si and fluorine [atm%] are then determined. As the X-ray photoelectron spectrometer, for example, a K-Alpha X-ray photoelectron spectrometer system manufactured by Thermo Fisher Scientific can be used.

[0045] The occurrence of outgassing in the hollow, sealed space surrounded by the Si substrate 80 having the SiN layer 83 on the outermost surface, the polyimide film 90, and the test substrate 70 can be evaluated by the change in film thickness of the portion 85 on the SiN layer 83 that is not in contact with the polyimide film 90 before and after the occurrence of outgassing. The change in film thickness at the portion 85 before and after the generation of outgassing is due to the accumulation of outgassing components derived from the photosensitive composition. The film thickness of portion 85 can be measured by using X-ray reflectometry (XRR).

[0046] Alternatively, the presence or absence of outgassing in the hollow, sealed space surrounded by the Si substrate 80 having the SiN layer 83 on the outermost surface, the polyimide film 90, and the test substrate 70 can be evaluated by the contact angle of a portion 85 on the SiN layer 83 that is not in contact with the polyimide film 90, as an alternative indicator of the weight change on the SiN layer 83 before and after the outgassing. When the contact angle of the portion 85 is preferably less than 50°, the photosensitive composition forming the photosensitive composition layer 60 is one that suppresses outgassing within the hollow, sealed space. In a microelectronic device that utilizes a hollow structure fabricated using this photosensitive composition, a frequency shift to the negative side is unlikely to occur.

[0047] The evaluation of the contact angle of the portion 85 is performed by using a contact angle meter to measure the contact angle when water is dropped onto the portion 85 on the SiN layer 83 exposed to the hollow sealed space and not in contact with the polyimide film. As the contact angle meter, for example, DMo-501 manufactured by Kyowa Interface Science Co., Ltd. can be used.

[0048] When the photosensitive composition of this embodiment is evaluated on a SiN layer by X-ray photoelectron spectroscopy, the carbon to silicon ratio (C / Si), the amount of fluorine detected, the change in film thickness before and after outgassing, and the contact angle can be controlled by selecting the composition (constituent components, contents) of the photosensitive composition and the exposure conditions (exposure amount to the photosensitive composition layer) in step (1-3).

[0049] In another embodiment of the photosensitive composition, when the cured product is evaluated in the following [Pressure Cooker Test], the amount of fluorine ions eluted from the cured product is preferably less than 1 ppm.

[0050] [Pressure Cooker Test] One embodiment of the pressure cooker test is a form in which the following steps (1), (2), (3), (4), (5), and (6) are performed in this order.

[0051] Procedure (1): A photosensitive composition dissolved in methyl ethyl ketone to adjust the solid content to 75% by mass is applied onto a release polyethylene terephthalate (PET) film using an applicator, and the film is dried in an oven at 70°C for 10 minutes to form a photosensitive composition layer with a thickness of 20 μm.

[0052] Step (2): Next, the release PET film is peeled off, and then the photosensitive composition layer is exposed using a ghi broadband exposure machine to obtain a cured film.

[0053] Step (3): The cured film is then post-exposure baked on a hot plate at 90°C for 5 minutes, and then cured by heating in an oven at 200°C for 1 hour to obtain the desired cured product.

[0054] Step (4): Next, 4 g of the cured product and 40 g of pure water as an extraction solvent are placed in a polytetrafluoroethylene (PTFE) resin container with a lid, and the lid is closed.

[0055] Step (5): Next, the PTFE resin container with the lid closed is placed in a stainless steel autoclave and treated in an oven at 120°C under 2 atmospheres for 20 hours.

[0056] Step (6): After cooling to room temperature (23°C), the extract in the PTFE resin container with the lid closed is collected and the amount of fluoride ions eluted from the cured product is determined by ion chromatography.

[0057] When a cured product is evaluated in a [pressure cooker test] in which the above-mentioned series of steps (1), (2), (3), (4), (5), and (6) are performed, the photosensitive composition of the embodiment in which the amount of fluoride ions eluted from the cured product is less than 1 ppm is less likely to cause corrosion of the interdigital electrodes when used to fabricate a hollow structure. In the photosensitive composition of this other embodiment, when the cured product is evaluated by the above-mentioned [Pressure Cooker Test], the amount of fluoride ions eluted from the cured product is preferably less than 1 ppm, more preferably less than 0.5 ppm, and the smaller the amount of fluoride ions eluted from the cured product, the better.

[0058] In the above step (6), the amount of fluoride ions eluted from the cured product is determined by ion chromatography as follows: The peak heights of samples with three known fluoride ion concentrations are measured, and a calibration curve is created. The peak heights of the extract to be evaluated are then measured, and the amount of fluoride ions eluted from the cured product is then determined using the calibration curve.

[0059] In the photosensitive composition of another embodiment, the amount of fluoride ions eluted when the cured product is evaluated in the above-mentioned [Pressure Cooker Test] can be controlled by selecting the composition of the photosensitive composition, and particularly preferably, can be controlled by selecting the component (I1) described below as a cationic polymerization initiator.

[0060] The photosensitive composition of the embodiment described above is the material for at least one of the side walls and the top plate portion that constitute the hollow structure, and such photosensitive compositions include those containing an epoxy group-containing compound and a cationic polymerization initiator.

[0061] When a photosensitive resin film is formed using such a photosensitive composition and selectively exposed to light, the cationic portion of the cationic polymerization initiator decomposes in the exposed portion of the photosensitive resin film to generate an acid. The acid causes ring-opening polymerization of the epoxy group in the epoxy group-containing compound, reducing the solubility of the epoxy group-containing compound in a developer containing an organic solvent (organic developer). Meanwhile, the solubility of the epoxy group-containing compound in an organic developer remains unchanged in the unexposed portion of the photosensitive resin film, resulting in a difference in solubility in an organic developer between the exposed and unexposed portions of the photosensitive resin film. Therefore, when the photosensitive resin film is developed with an organic developer, the unexposed portion is dissolved and removed, and the exposed portion becomes a residual image, forming a negative pattern.

[0062] <Epoxy group-containing compounds> The epoxy group-containing compound (hereinafter also referred to as "component (A)") used has a sufficient number of epoxy groups to form a negative pattern upon exposure. Examples of the component (A) include a tri- or higher functional epoxy compound that is solid at 23°C (hereinafter also referred to as "component (A1)"), and an epoxy compound that is liquid at 23°C (hereinafter also referred to as "component (A2)").

[0063] <<A tri- or higher functional polyfunctional epoxy compound that is solid at 23°C: component (A1)>> The tri- or higher functional polyfunctional epoxy compound (component (A1)) that may be contained in the photosensitive composition of this embodiment and that is solid at 23°C is solid at 23°C and has a softening point of, for example, 50°C or higher, or may be 55°C or higher, or may be 60°C or higher and 80°C or lower, or may be 65°C or higher and 75°C or lower. In this specification, the softening point of the epoxy group-containing compound is a value measured by the ring and ball method.

[0064] The epoxy equivalent of the component (A1) is preferably 180 g / eq. or more and 300 g / eq. or less, and more preferably 200 g / eq. or more and 240 g / eq. or less. In this specification, the epoxy equivalent of an epoxy group-containing compound can be measured by potentiometric titration as described in JIS K-7236. Examples of methods for measuring the epoxy equivalent by potentiometric titration include the hydrochloric acid-dioxane method, the perchloric acid-tetraethylammonium bromide method, the perchloric acid-cetyltrimethylammonium bromide method, the hydrochloric acid-potassium iodide method, and the Dubertaki method using a hydrogen bromide-acetic acid solution.

[0065] The component (A1) can be a novolac epoxy resin, such as a bisphenol novolac epoxy resin or a novolac epoxy resin having a structural unit represented by the general formula (anv1) described below. Alternatively, a trifunctional epoxy compound having three epoxy groups in the molecule can be used as the component (A1).

[0066] Bisphenol novolac epoxy resin Examples of bisphenol novolac epoxy resins include polyfunctional epoxy resins produced by reacting bisphenol novolac resin with epichlorohydrin, and polyfunctional epoxy resins obtained by novolakizing bisphenol glycidyl ether. Among these, bisphenol A novolac epoxy resins are preferred because of their easy availability.

[0067] Suitable examples of bisphenol novolac epoxy resins include resins represented by the following general formula (A1-1).

[0068] [ka] [In formula (A1-1), R p1 and R p2 are each independently a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. p1 may be the same or different. p2may be the same or different. n1 is an integer of 1 to 5. R EP is an epoxy group-containing group. EP may be the same or different from each other.

[0069] In the formula (A1-1), R p1 , R p2 The alkyl group having 1 to 5 carbon atoms is, for example, a linear, branched, or cyclic alkyl group having 1 to 5 carbon atoms. Examples of the linear or branched alkyl group include a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a tert-butyl group, a pentyl group, an isopentyl group, and a neopentyl group, and examples of the cyclic alkyl group include a cyclobutyl group and a cyclopentyl group. Among them, R p1 , R p2 As the alkyl group, a hydrogen atom or a linear or branched alkyl group is preferred, a hydrogen atom or a linear alkyl group is more preferred, and a hydrogen atom or a methyl group is particularly preferred. In the formula (A1-1), a plurality of R p1 may be the same or different. p2 may be the same as or different from each other.

[0070] In the formula (A1-1), n1 is an integer of 1 to 5, preferably 2 or 3, and more preferably 2.

[0071] In the formula (A1-1), R EP is an epoxy group-containing group. R EP The epoxy group-containing group is not particularly limited, and examples thereof include a group consisting of only epoxy groups; a group consisting of only alicyclic epoxy groups; and a group having an epoxy group or alicyclic epoxy group and a divalent linking group. The alicyclic epoxy group is an alicyclic group having an oxacyclopropane structure, which is a three-membered ring ether, and specifically, a group having an alicyclic group and an oxacyclopropane structure. The alicyclic group that forms the basic skeleton of the alicyclic epoxy group may be monocyclic or polycyclic. Examples of monocyclic alicyclic groups include cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, and cyclooctyl groups. Examples of polycyclic alicyclic groups include norbornyl, isobornyl, tricyclononyl, tricyclodecyl, and tetracyclododecyl groups. The hydrogen atoms of these alicyclic groups may be substituted with alkyl, alkoxy, or hydroxyl groups. In the case of a group having an epoxy group or an alicyclic epoxy group and a divalent linking group, it is preferable that the epoxy group or the alicyclic epoxy group is linked via the divalent linking group bonded to an oxygen atom (—O—) in the formula.

[0072] Here, the divalent linking group is not particularly limited, but suitable examples include a divalent hydrocarbon group which may have a substituent, and a divalent linking group containing a hetero atom.

[0073] Regarding optionally substituted divalent hydrocarbon groups: Such a divalent hydrocarbon group may be an aliphatic hydrocarbon group or an aromatic hydrocarbon group. The aliphatic hydrocarbon group in the divalent hydrocarbon group may be saturated or unsaturated, and is usually preferably saturated. More specifically, the aliphatic hydrocarbon group may be a straight-chain or branched-chain aliphatic hydrocarbon group, or an aliphatic hydrocarbon group containing a ring in its structure.

[0074] The linear aliphatic hydrocarbon group preferably has 1 to 10 carbon atoms, more preferably 1 to 6, even more preferably 1 to 4, and most preferably 1 to 3. The linear aliphatic hydrocarbon group is preferably a linear alkylene group, and specific examples thereof include a methylene group [-CH2-], an ethylene group [-(CH2)2-], a trimethylene group [-(CH2)3-], a tetramethylene group [-(CH2)4-], and a pentamethylene group [-(CH2)5-]. The branched aliphatic hydrocarbon group preferably has 2 to 10 carbon atoms, more preferably 2 to 6 carbon atoms, even more preferably 2 to 4 carbon atoms, and most preferably 2 or 3 carbon atoms. The branched aliphatic hydrocarbon group is preferably a branched alkylene group, and specific examples thereof include alkyl alkylene groups such as alkylmethylene groups such as -CH(CH3)-, -CH(CH2CH3)-, -C(CH3)2-, -C(CH3)(CH2CH3)-, -C(CH3)(CH2CH2CH3)-, and -C(CH2CH3)2-; alkylethylene groups such as -CH(CH3)CH2-, -CH(CH3)CH(CH3)-, -C(CH3)2CH2-, -CH(CH2CH3)CH2-, and -C(CH2CH3)2-CH2-; alkyl trimethylene groups such as -CH(CH3)CH2CH2- and -CH2CH(CH3)CH2-; and alkyl tetramethylene groups such as -CH(CH3)CH2CH2CH2- and -CH2CH(CH3)CH2CH2-. The alkyl group in the alkylalkylene group is preferably a linear alkyl group having 1 to 5 carbon atoms.

[0075] Examples of the aliphatic hydrocarbon group containing a ring in its structure include an alicyclic hydrocarbon group (a group in which two hydrogen atoms have been removed from an aliphatic hydrocarbon ring), a group in which an alicyclic hydrocarbon group is bonded to the end of a straight-chain or branched-chain aliphatic hydrocarbon group, and a group in which an alicyclic hydrocarbon group is interposed in the middle of a straight-chain or branched-chain aliphatic hydrocarbon group. Examples of the straight-chain or branched-chain aliphatic hydrocarbon group include the same as those described above. The alicyclic hydrocarbon group preferably has 3 to 20 carbon atoms, and more preferably 3 to 12 carbon atoms. The alicyclic hydrocarbon group may be a polycyclic group or a monocyclic group. The monocyclic alicyclic hydrocarbon group is preferably a group in which two hydrogen atoms have been removed from a monocycloalkane. The monocycloalkane preferably has 3 to 6 carbon atoms, and specific examples thereof include cyclopentane and cyclohexane. The polycyclic alicyclic hydrocarbon group is preferably a group in which two hydrogen atoms have been removed from a polycycloalkane, and the polycycloalkane preferably has 7 to 12 carbon atoms, and specific examples thereof include adamantane, norbornane, isobornane, tricyclodecane, and tetracyclododecane.

[0076] The aromatic hydrocarbon group in the divalent hydrocarbon group is a hydrocarbon group having at least one aromatic ring. This aromatic ring is not particularly limited as long as it is a cyclic conjugated system having (4n+2) π electrons, and may be monocyclic or polycyclic. The number of carbon atoms in the aromatic ring is preferably 5 to 30, more preferably 5 to 20, even more preferably 6 to 15, and particularly preferably 6 to 12. Specific examples of the aromatic ring include aromatic hydrocarbon rings such as benzene, naphthalene, anthracene, and phenanthrene; and aromatic heterocycles in which some of the carbon atoms constituting the aromatic hydrocarbon ring are substituted with heteroatoms. Examples of heteroatoms in the aromatic heterocycle include oxygen atoms, sulfur atoms, and nitrogen atoms. Specific examples of the aromatic heterocycle include pyridine rings and thiophene rings. Specific examples of the aromatic hydrocarbon group include groups in which two hydrogen atoms have been removed from the aromatic hydrocarbon ring or aromatic heterocycle (arylene groups or heteroarylene groups); groups in which two hydrogen atoms have been removed from an aromatic compound containing two or more aromatic rings (e.g., biphenyl, fluorene, etc.); and groups in which one hydrogen atom of a group in which one hydrogen atom has been removed from the aromatic hydrocarbon ring or aromatic heterocycle (aryl group or heteroaryl group) has been substituted with an alkylene group (e.g., groups in which one hydrogen atom has been further removed from the aryl group in an arylalkyl group such as a benzyl group, phenethyl group, 1-naphthylmethyl group, 2-naphthylmethyl group, 1-naphthylethyl group, or 2-naphthylethyl group). The number of carbon atoms in the alkylene group bonded to the aryl group or heteroaryl group is preferably 1 to 4, more preferably 1 to 2, and particularly preferably 1.

[0077] The divalent hydrocarbon group may have a substituent. The linear or branched aliphatic hydrocarbon group as the divalent hydrocarbon group may or may not have a substituent, such as a fluorine atom, a fluorinated alkyl group having 1 to 5 carbon atoms and substituted with a fluorine atom, or a carbonyl group.

[0078] The alicyclic hydrocarbon group in the aliphatic hydrocarbon group containing a ring in its structure as a divalent hydrocarbon group may or may not have a substituent, such as an alkyl group, an alkoxy group, a halogen atom, a halogenated alkyl group, a hydroxyl group, or a carbonyl group. The alkyl group as the substituent is preferably an alkyl group having 1 to 5 carbon atoms, and most preferably a methyl group, an ethyl group, a propyl group, an n-butyl group, or a tert-butyl group. The alkoxy group as the substituent is preferably an alkoxy group having 1 to 5 carbon atoms, more preferably a methoxy group, an ethoxy group, an n-propoxy group, an iso-propoxy group, an n-butoxy group, or a tert-butoxy group, and most preferably a methoxy group or an ethoxy group. Examples of the halogen atom as the substituent include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, with a fluorine atom being preferred. Examples of the halogenated alkyl group as the substituent include groups in which some or all of the hydrogen atoms of the alkyl group have been substituted with the halogen atoms. In the alicyclic hydrocarbon group, some of the carbon atoms constituting the ring structure may be substituted with a substituent containing a heteroatom, and the heteroatom-containing substituent is preferably -O-, -C(=O)-O-, -S-, -S(=O)2-, or -S(=O)2-O-.

[0079] In the aromatic hydrocarbon group as a divalent hydrocarbon group, a hydrogen atom of the aromatic hydrocarbon group may be substituted with a substituent. For example, a hydrogen atom bonded to an aromatic ring in the aromatic hydrocarbon group may be substituted with a substituent. Examples of the substituent include an alkyl group, an alkoxy group, a halogen atom, a halogenated alkyl group, and a hydroxyl group. The alkyl group as the substituent is preferably an alkyl group having 1 to 5 carbon atoms, and most preferably a methyl group, an ethyl group, a propyl group, an n-butyl group, or a tert-butyl group. Examples of the alkoxy group, halogen atom and halogenated alkyl group as the substituent include those exemplified as the substituent substituting the hydrogen atom of the alicyclic hydrocarbon group.

[0080] Regarding divalent linking groups containing heteroatoms: The heteroatom in the divalent linking group containing a heteroatom is an atom other than a carbon atom or a hydrogen atom, and examples thereof include an oxygen atom, a nitrogen atom, a sulfur atom, and a halogen atom.

[0081] In the divalent linking group containing a hetero atom, preferred examples of the linking group include -O-, -C(=O)-O-, -C(=O)-, -OC(=O)-O-; -C(=O)-NH-, -NH-, -NH-C(=O)-O-, -NH-C(=NH)- (H may be substituted with a substituent such as an alkyl group or an acyl group); -S-, -S(=O)2-, -S(=O)2-O-, and groups represented by the general formula -Y 21 -OY 22 -, -Y 21 -O-, -Y 21 -C(=O)-O-, -C(=O)-OY 21 , -[Y 21 -C(=O)-O] m” -Y 22 -or- Y 21 -OC(=O)-Y 22 -, wherein Y 21 and Y 22 are each independently a divalent hydrocarbon group which may have a substituent, O is an oxygen atom, and m″ is an integer of 1 to 3. When the divalent linking group containing a hetero atom is -C(=O)-NH-, -NH-, -NH-C(=O)-O-, or -NH-C(=NH)-, the H may be substituted with a substituent such as an alkyl group, acyl, etc. The substituent (alkyl group, acyl group, etc.) preferably has 1 to 10 carbon atoms, more preferably 1 to 8, and particularly preferably 1 to 5 carbon atoms. Formula-Y 21 -OY 22 -, -Y 21 -O-, -Y 21 -C(=O)-O-, -C(=O)-OY 21 -, -[Y 21 -C(=O)-O] m” -Y 22 -or- Y 21 -OC(=O)-Y 22 -Medium, Y 21 and Y 22 are each independently a divalent hydrocarbon group which may have a substituent. Examples of the divalent hydrocarbon group include the same as the "divalent hydrocarbon group which may have a substituent" listed above in the description of the divalent linking group. Y 21 As the alkyl group, a straight-chain aliphatic hydrocarbon group is preferred, a straight-chain alkylene group is more preferred, a straight-chain alkylene group having 1 to 5 carbon atoms is even more preferred, and a methylene group or ethylene group is particularly preferred. Y 22 is preferably a linear or branched aliphatic hydrocarbon group, more preferably a methylene group, an ethylene group or an alkylmethylene group. The alkyl group in the alkylmethylene group is preferably a linear alkyl group having 1 to 5 carbon atoms, more preferably a linear alkyl group having 1 to 3 carbon atoms, and most preferably a methyl group. Formula − [Y 21 -C(=O)-O] m” -Y 22 In the group represented by -, m" is an integer of 1 to 3, preferably 1 or 2, and particularly preferably 1. That is, the group represented by the formula -[Y 21 -C(=O)-O] m” -Y 22 The group represented by - is a group represented by the formula -Y 21-C(=O)-OY 22 Particularly preferred is a group represented by the formula -(CH2) a’ -C(=O)-O-(CH2) b’ In the formula, a' is an integer of 1 to 10, preferably an integer of 1 to 8, more preferably an integer of 1 to 5, even more preferably 1 or 2, and most preferably 1. b' is an integer of 1 to 10, preferably an integer of 1 to 8, more preferably an integer of 1 to 5, even more preferably 1 or 2, and most preferably 1.

[0082] Among them, R EP The epoxy group-containing group in is preferably a glycidyl group.

[0083] Novolac-type epoxy resin having a structural unit represented by general formula (anv1) Suitable examples of the component (A1) include novolac epoxy resins having a structural unit represented by the following general formula (anv1):

[0084] [ka] [In the formula, R EP is an epoxy group-containing group. a22 and R a23 are each independently a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a halogen atom.

[0085] In the formula (anv1), R a22 , R a23 The alkyl group having 1 to 5 carbon atoms is represented by R p1 , R p2 The alkyl group has 1 to 5 carbon atoms. R a22 , R a23 The halogen atom is preferably a chlorine atom or a bromine atom. In the formula (anv1), R EP represents R in the formula (A1-1). EP and a glycidyl group is preferred.

[0086] Specific examples of the constitutional unit represented by the formula (anv1) are shown below.

[0087] [ka]

[0088] The component (A1) may be a resin consisting solely of the structural unit (anv1), or a resin containing the structural unit (anv1) and other structural units. Examples of resins consisting solely of the structural unit (anv1) include phenol novolac epoxy resins and cresol novolac epoxy resins. Examples of such other structural units include structural units represented by the following general formulae (anv2) to (anv3).

[0089] [ka] [In the formula, R a24 R is a hydrocarbon group which may have a substituent. a25 ~R a26 , R a28 ~R a30 R are each independently a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a halogen atom. a27 represents an epoxy group-containing group or a hydrocarbon group which may have a substituent.

[0090] In the formula (anv2), R a24 is a hydrocarbon group which may have a substituent. Examples of the hydrocarbon group which may have a substituent include a linear or branched alkyl group, and a cyclic hydrocarbon group. The linear alkyl group preferably has 1 to 5 carbon atoms, more preferably 1 to 4 carbon atoms, and even more preferably 1 or 2 carbon atoms. Specific examples include a methyl group, an ethyl group, an n-propyl group, an n-butyl group, an n-pentyl group, etc. Among these, a methyl group, an ethyl group, or an n-butyl group is preferred, and a methyl group or an ethyl group is more preferred.

[0091] The branched alkyl group preferably has 3 to 10 carbon atoms, more preferably 3 to 5. Specific examples include an isopropyl group, an isobutyl group, a tert-butyl group, an isopentyl group, a neopentyl group, a 1,1-diethylpropyl group, and a 2,2-dimethylbutyl group, with an isopropyl group being preferred.

[0092] R a24 When is a cyclic hydrocarbon group, the hydrocarbon group may be an aliphatic hydrocarbon group or an aromatic hydrocarbon group, and may be a polycyclic group or a monocyclic group. The monocyclic aliphatic hydrocarbon group is preferably a group in which one hydrogen atom has been removed from a monocycloalkane. The monocycloalkane preferably has 3 to 6 carbon atoms, and specific examples include cyclopentane and cyclohexane. The aliphatic hydrocarbon group that is a polycyclic group is preferably a group in which one hydrogen atom has been removed from a polycycloalkane, and the polycycloalkane preferably has 7 to 12 carbon atoms, and specific examples thereof include adamantane, norbornane, isobornane, tricyclodecane, and tetracyclododecane.

[0093] R a24 When the cyclic hydrocarbon group is an aromatic hydrocarbon group, the aromatic hydrocarbon group is a hydrocarbon group having at least one aromatic ring. The aromatic ring is not particularly limited as long as it is a cyclic conjugated system having 4n+2 π electrons, and may be monocyclic or polycyclic. The number of carbon atoms in the aromatic ring is preferably 5 to 30, more preferably 5 to 20, even more preferably 6 to 15, and particularly preferably 6 to 12. Specific examples of the aromatic ring include aromatic hydrocarbon rings such as benzene, naphthalene, anthracene, and phenanthrene; and aromatic heterocycles in which some of the carbon atoms constituting the aromatic hydrocarbon ring are substituted with heteroatoms. Examples of heteroatoms in the aromatic heterocycle include oxygen atoms, sulfur atoms, and nitrogen atoms. Specific examples of the aromatic heterocycle include pyridine rings and thiophene rings. R a24Specific examples of the aromatic hydrocarbon group in the formula (I) include a group (aryl group or heteroaryl group) in which one hydrogen atom has been removed from the aromatic hydrocarbon ring or aromatic heterocycle; a group in which one hydrogen atom has been removed from an aromatic compound containing two or more aromatic rings (e.g., biphenyl, fluorene, etc.); and a group in which one hydrogen atom of the aromatic hydrocarbon ring or aromatic heterocycle has been substituted with an alkylene group (e.g., arylalkyl groups such as benzyl group, phenethyl group, 1-naphthylmethyl group, 2-naphthylmethyl group, 1-naphthylethyl group, and 2-naphthylethyl group). The alkylene group bonded to the aromatic hydrocarbon ring or aromatic heterocycle preferably has 1 to 4 carbon atoms, more preferably 1 to 2 carbon atoms, and particularly preferably 1 carbon atom.

[0094] In the formulas (anv2) and (anv3), R a25 ~R a26 , R a28 ~R a30 are each independently a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a halogen atom. The alkyl group having 1 to 5 carbon atoms and the halogen atom are each defined as R a22 , R a23 is the same as:

[0095] In the formula (anv3), R a27 R is an epoxy group-containing group or a hydrocarbon group which may have a substituent. a27 The epoxy group-containing group is R EP Similar to R a27 The hydrocarbon group which may have a substituent is R a24 is the same as:

[0096] Specific examples of the structural units represented by the formulae (anv2) to (anv3) are shown below.

[0097] [ka]

[0098] When the component (A1) contains other structural units in addition to the structural unit (anv1), there are no particular limitations on the proportion of each structural unit within the component (A1), but the total amount of structural units having an epoxy group relative to the total amount of all structural units constituting the component (A1) is preferably 10 to 90 mol %, more preferably 20 to 80 mol %, and even more preferably 30 to 70 mol %.

[0099] Trifunctional epoxy compounds with three epoxy groups in the molecule Suitable examples of the component (A1) include trifunctional epoxy compounds having three epoxy groups in the molecule. Examples of trifunctional epoxy compounds include trimethylolpropane triglycidyl ether, glycerin triglycidyl ether, tris(4-hydroxyphenyl)methane triglycidyl ether, and trifunctional epoxy compounds represented by the following general formula (A1-2).

[0100] [ka] [In formula (A1-2), R p3 , R p4 and R p5 Rm each independently represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. EP is an epoxy group-containing group. EP may be the same or different from each other.

[0101] In the formula (A1-2), R p3 , R p4 and R p5 The alkyl group having 1 to 5 carbon atoms is, for example, a linear, branched, or cyclic alkyl group having 1 to 5 carbon atoms. Examples of the linear or branched alkyl group include a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a tert-butyl group, a pentyl group, an isopentyl group, and a neopentyl group, and examples of the cyclic alkyl group include a cyclobutyl group and a cyclopentyl group. Among them, R p3 , R p4 and Rp5 Each of the groups is preferably a hydrogen atom or a linear or branched alkyl group, more preferably a hydrogen atom or a linear alkyl group, further preferably a hydrogen atom or a methyl group, and particularly preferably a methyl group.

[0102] In the formula (A1-2), Rm EP is an epoxy group-containing group, and R EP and a glycidyl group is preferred. Multiple Rm EP may be the same as or different from each other.

[0103] Specific examples of the trifunctional epoxy compound represented by the formula (A1-2) are shown below.

[0104] [ka]

[0105] As the trifunctional epoxy compound, compounds having a structure in which the distance between the three epoxy groups is large within the molecule are preferred, as they are less likely to undergo an intramolecular crosslinking reaction; tris(4-hydroxyphenyl)methane triglycidyl ether or the trifunctional epoxy compound represented by the above general formula (A1-2) are more preferred; the trifunctional epoxy compound represented by the above general formula (A1-2) is particularly preferred; and the trifunctional epoxy compound represented by the above formula (A1-2-1) is most preferred.

[0106] Commercially available products of component (A1) include, for example, jER-152, jER-154, jER-157S70, and jER-157S65 (all manufactured by Mitsubishi Chemical Corporation); EPICLON N-740, EPICLON N-740, EPICLON N-770, EPICLON N-775, EPICLON N-660, EPICLON N-665, EPICLON N-670, EPICLON N-673, EPICLON N-680, EPICLON N-690, EPICLON N-695, and EPICLON HP5000 (all manufactured by DIC Corporation); EOCN-1020 (manufactured by Nippon Kayaku Co., Ltd.); YDCN-704 (manufactured by Nippon Steel Chemical & Material Co., Ltd.); and TECHMORE VG3101L (manufactured by Printec Co., Ltd.).

[0107] As the component (A1), one type may be used alone, or two or more types may be used in combination. In the photosensitive composition of this embodiment, the content of the component (A1) is preferably 90% by mass or more, more preferably 90 to 99.9% by mass, even more preferably 95 to 99.9% by mass, and particularly preferably 97 to 99.5% by mass, relative to the total mass (100% by mass) of the solid content of the photosensitive composition.

[0108] <Epoxy compound that is liquid at 23°C: component (A2)> The epoxy compound that is liquid at 23°C (hereinafter also referred to as "component (A2)") that may be contained in the photosensitive composition of this embodiment has an epoxy equivalent of, for example, 200 g / eq. or less, preferably 90 g / eq. or more and 180 g / eq. or less, and more preferably 120 g / eq. or more and 150 g / eq. or less. The molecular weight of the component (A2) is, for example, 300 or less.

[0109] Examples of the component (A2) include aliphatic epoxy resins that are liquid at 23°C. Examples of the aliphatic epoxy resin include a compound containing a partial structure represented by the following general formula (A2-m1) (hereinafter also referred to as "component (m1)").

[0110] [ka] [In the formula, n2 is an integer of 1 to 4.]

[0111] In formula (A2-m1), n2 represents an integer of 1 to 4, preferably an integer of 1 to 3, and more preferably 2.

[0112] Examples of the component (m1) include compounds in which a plurality of partial structures represented by the general formula (A2-m1) are bonded via a divalent linking group or a single bond. Among these, compounds in which a plurality of partial structures represented by the general formula (A2-m1) are bonded via a divalent linking group are preferred. The divalent linking group here is not particularly limited, but suitable examples include a divalent hydrocarbon group which may have a substituent, a divalent linking group containing a hetero atom, etc. The divalent hydrocarbon group which may have a substituent and the divalent linking group containing a hetero atom are represented by R EP The divalent hydrocarbon group which may have a substituent and the divalent linking group containing a hetero atom are the same as those explained in (epoxy group-containing group), and among these, the divalent linking group containing a hetero atom is preferred. 21 a group represented by —C(═O)—O—, —C(═O)—OY 21 A group represented by Y - is more preferred. 21 As the alkyl group, a straight-chain aliphatic hydrocarbon group is preferred, a straight-chain alkylene group is more preferred, a straight-chain alkylene group having 1 to 5 carbon atoms is even more preferred, and a methylene group or ethylene group is particularly preferred.

[0113] Furthermore, the component (A2) also preferably includes a compound represented by the following general formula (A2-m2) (hereinafter also referred to as "component (m2)").

[0114] [ka] [In the formula, R EP is an epoxy group-containing group. EPmay be the same or different from each other.

[0115] In the above formula (A2-m2), R EP is an epoxy group-containing group, and R EP is the same as:

[0116] Further examples of the component (A2) include epoxidized polybutadiene, trimethylolpropane triglycidyl ether, glycerin triglycidyl ether; pentaerythritol tetraglycidyl ether, ditrimethylolpropane tetraglycidyl ether, diglycerin tetraglycidyl ether, erythritol tetraglycidyl ether; xylitol pentaglycidyl ether, dipentaerythritol pentaglycidyl ether, inositol pentaglycidyl ether; dipentaerythritol hexaglycidyl ether, sorbitol hexaglycidyl ether, and inositol hexaglycidyl ether.

[0117] Commercially available products of component (A2) include, for example, ADEKA RESIN EP-4080S, EP-4085S, and EP-4088S (all manufactured by ADEKA Corporation); CELLOXIDE 2021P, CELLOXIDE 2081, CELLOXIDE 2083, CELLOXIDE 2085, CELLOXIDE 8000, CELLOXIDE 8010, EPOLEAD PB 3600, and EPOLEAD PB 4700 (all manufactured by Daicel Corporation); EPOCALIC THI-DE, DE-102, and DE-103 (all manufactured by ENEOS Corporation); and Denacol. EX-211L, EX-212L, EX-214L, EX-216L, EX-321L, EX-622, and EX-850L (all manufactured by Nagase ChemteX Corporation); TEPIC series such as TEPIC, TEPIC-VL, TEPIC-PAS, TEPIC-G, TEPIC-S, TEPIC-SP, TEPIC-SS, TEPIC-HP, TEPIC-L, TEPIC-FL, and TEPIC-UC (manufactured by Nissan Chemical Industries, Ltd.); Examples include MA-DGIC, DA-MGIC, and TOIC (manufactured by Shikoku Chemicals Corporation);

[0118] As the component (A2), one type may be used alone, or two or more types may be used in combination. The component (A2) preferably contains at least one selected from the group consisting of the component (m1) and the component (m2). In the photosensitive composition of this embodiment, when the component (A2) is a tri- or higher functional epoxy group-containing compound, the content of the component (A2) is preferably 1 to 10 parts by mass, more preferably 1.5 to 9 parts by mass, and even more preferably 2 to 8 parts by mass, per 100 parts by mass of the component (A1). When the component (A2) is a difunctional epoxy monomer, the content of the component (A2) is preferably 2 parts by mass or less per 100 parts by mass of the component (A1).

[0119] Examples of the epoxy group-containing compound (component (A)) that may be contained in the photosensitive composition of this embodiment include, in addition to the compounds described above, acrylic resins having epoxy group-containing units.

[0120] In the photosensitive composition of the present embodiment, among the component (A), it is preferable that the component (A) contains a trifunctional or higher functional epoxy group-containing compound, and that the content of the bifunctional epoxy monomer is 2 mass% or less relative to the total mass of the trifunctional or higher functional epoxy group-containing compound and the bifunctional epoxy monomer. Suitable examples of such epoxy group-containing compounds include novolac type epoxy resins and trisphenol type polyglycidyl ether compounds having three or more epoxy groups in one molecule. Suitable examples of the novolac epoxy resin include bisphenol novolac epoxy resins and novolac epoxy resins having a structural unit represented by the general formula (anv1) described above. Suitable examples of the trisphenol-type polyhydric glycidyl ether compound include trifunctional epoxy compounds having three epoxy groups in the molecule.

[0121] The bisphenol novolac epoxy resin is preferably a resin represented by the above general formula (A1-1), and examples thereof include those containing a bisphenol novolac epoxy resin and having a bisphenol epoxy monomer content of 2 mass% or less relative to the total mass of the bisphenol novolac epoxy resin and the bisphenol epoxy monomer. When the photosensitive composition of this embodiment contains a bisphenol novolac epoxy resin, the content of the bisphenol epoxy monomer is preferably 2 mass% or less, more preferably 1.5 mass% or less, based on the total mass of the bisphenol novolac epoxy resin and the bisphenol epoxy monomer. The lower the content of the bisphenol epoxy monomer, the more easily outgassing can be suppressed. Examples of bisphenol epoxy monomers include bisphenol diglycidyl ether and bisphenol monoglycidyl ether.

[0122] In this specification and claims, the molecular weight of component (A) is expressed as the weight average molecular weight (Mw) and number average molecular weight (Mn) in terms of polystyrene as determined by gel permeation chromatography (GPC).

[0123] In a preferred bisphenol novolac epoxy resin, for example, the weight average molecular weight (Mw) is 4000 or more, preferably 4000 or more and 8000 or less, and more preferably 4000 or more and 6000 or less. If the weight average molecular weight is 4000 or more, hollow structures having sufficient strength can be easily and stably produced. The upper limit of the molecular weight distribution of the entire bisphenol novolac epoxy resin is, for example, 10,000 or less, and may be 8,000 or less, or 6,000 or less. As mentioned above, the bisphenol epoxy monomer refers to a monomer containing at least one of bisphenol monoglycidyl ether and bisphenol diglycidyl ether, and having a molecular weight of 500 or less. The weight average molecular weight of the bisphenol novolac epoxy resin is preferably 4,000 or more, calculated by removing low molecular weight components. The molecular weight dispersity (Mw / Mn) of the bisphenol novolac epoxy resin is preferably 4.0 or less, and may be 2.0 or more and 4.0 or less, or 2.0 or more and 3.0 or less.

[0124] As the novolac epoxy resin having a constitutional unit represented by the above general formula (anv1), a phenol novolac epoxy resin or a cresol novolac epoxy resin is preferred, and a cresol novolac epoxy resin is more preferred. In the case of a novolac epoxy resin having a structural unit represented by general formula (anv1), the content of the bifunctional epoxy monomer is, for example, 2 mass% or less, and preferably 0 mass%, relative to the total mass of the novolac epoxy resin having a structural unit represented by general formula (anv1) and the bifunctional epoxy monomer.

[0125] As the trifunctional epoxy compound having three epoxy groups in the molecule, a trifunctional epoxy compound represented by the above general formula (A1-2) is preferred, a trifunctional epoxy compound represented by the above formula (A1-2-1) or a trifunctional epoxy compound represented by the above formula (A1-2-2) is more preferred, and a trifunctional epoxy compound represented by the above formula (A1-2-1) is even more preferred. In the case of a trifunctional epoxy compound represented by general formula (A1-2), the content of the bifunctional epoxy monomer is, for example, 2 mass% or less, and preferably 0 mass%, relative to the total mass of the trifunctional epoxy compound represented by general formula (A1-2) and the bifunctional epoxy monomer.

[0126] <Cationic polymerization initiator> A cationic polymerization initiator (hereinafter also referred to as "component (I)") is a compound that generates cations when irradiated with active energy rays such as ultraviolet rays, far ultraviolet rays, excimer laser light such as KrF or ArF, X-rays, or electron beams, and the cations can serve as polymerization initiators. Examples of the component (I) include a compound consisting of an anion moiety containing a borate anion and a cation moiety (hereinafter also referred to as "component (I1)"), and cationic polymerization initiators other than component (I1) (other cationic polymerization initiators).

[0127] <Compound having an anion moiety containing a borate anion and a cation moiety> A compound (component (I1)) consisting of an anion moiety containing a borate anion and a cation moiety generates a relatively strong acid upon exposure. Therefore, the use of a photosensitive composition containing component (I1) provides sufficient sensitivity and allows for the formation of good patterns. Furthermore, the use of component (I1) helps to suppress metal corrosion of the interdigital electrodes and reduces the risk of toxicity. Suitable examples of the component (I1) include compounds represented by the following general formula (I1).

[0128] [ka] [In the formula, R b01 ~R b04 are each independently an aryl group which may have a substituent, or a fluorine atom; q is an integer of 1 or more; q+ is a q-valent organic cation.

[0129] Anion section In the formula (I1), R b01 ~R b04 The aryl group in the formula (I) preferably has 5 to 30 carbon atoms, more preferably 5 to 20, still more preferably 6 to 15, and particularly preferably 6 to 12. Specific examples include a naphthyl group, a phenyl group, and an anthracenyl group, with a phenyl group being preferred because of its easy availability. R b01 ~R b04The aryl group in may have a substituent. The substituent is not particularly limited, but is preferably a halogen atom, a hydroxyl group, an alkyl group (preferably a linear or branched alkyl group, preferably having 1 to 5 carbon atoms), or a halogenated alkyl group, more preferably a halogen atom or a halogenated alkyl group having 1 to 5 carbon atoms, and particularly preferably a fluorine atom or a fluorinated alkyl group having 1 to 5 carbon atoms. When the aryl group has a fluorine atom, the polarity of the anion moiety is enhanced, which is preferable. Among them, R in formula (I1) b01 ~R b04 As each of the groups, a fluorinated phenyl group is preferred, and a perfluorophenyl group is particularly preferred.

[0130] A preferred example of the anion moiety of the compound represented by formula (I1) is tetrakis(pentafluorophenyl)borate ([B(C6F5)4] - );Tetrakis[(trifluoromethyl)phenyl]borate ([B(C6H4CF3)4] - );Difluorobis(pentafluorophenyl)borate ([(C6F5)2BF2] - ); Trifluoro(pentafluorophenyl)borate ([(C6F5)BF3] - );Tetrakis(difluorophenyl)borate ([B(C6H3F2)4] - ) etc. Among them, tetrakis(pentafluorophenyl)borate ([B(C6F5)4] - ) is particularly preferred.

[0131] Cation part In the formula (I1), Q q+ Suitable examples of the cation include sulfonium cations and iodonium cations, and organic cations represented by the following general formulas (ca-1) to (ca-5) are particularly preferred.

[0132] [ka] [In the formula, R 201 ~R207 , and R 211 ~R 212 R each independently represents an aryl group, a heteroaryl group, an alkyl group, or an alkenyl group, which may have a substituent. 201 ~R 203 , R 206 ~R 207 , R 211 ~R 212 may be bonded to each other to form a ring together with the sulfur atom in the formula. 208 ~R 209 R each independently represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. 210 is an optionally substituted aryl group, an optionally substituted alkyl group, an optionally substituted alkenyl group, or an optionally substituted -SO2- containing cyclic group. 201 represents -C(=O)- or -C(=O)-O-. Y 201 each independently represents an arylene group, an alkylene group, or an alkenylene group. x is 1 or 2. W 201 represents a (x+1)-valent linking group.

[0133] R 201 ~R 207 , and R 211 ~R 212 The aryl group in the formula (I) includes an unsubstituted aryl group having 6 to 20 carbon atoms, and a phenyl group or a naphthyl group is preferred. R 201 ~R 207 , and R 211 ~R 212 Examples of the heteroaryl group in the above formula (I) include those in which some of the carbon atoms constituting the aryl group have been substituted with heteroatoms. Examples of heteroatoms include oxygen atoms, sulfur atoms, and nitrogen atoms. Examples of this heteroaryl group include a group in which one hydrogen atom has been removed from 9H-thioxanthene; examples of the substituted heteroaryl group include a group in which one hydrogen atom has been removed from 9H-thioxanthen-9-one. R 201 ~R 207 , and R 211 ~R 212The alkyl group in the formula (I) is preferably a chain or cyclic alkyl group having 1 to 30 carbon atoms. R 201 ~R 207 , and R 211 ~R 212 The alkenyl group in the formula (I) preferably has 2 to 10 carbon atoms. R 201 ~R 207 , and R 210 ~R 212 Examples of the substituent that may be possessed by the group include an alkyl group, a halogen atom, a halogenated alkyl group, a carbonyl group, a cyano group, an amino group, an oxo group (═O), an aryl group, and groups represented by the following formulas (ca-r-1) to (ca-r-10):

[0134] [ka] [In the formula, R' 201 are each independently a hydrogen atom, an optionally substituted cyclic group, an optionally substituted chain alkyl group, or an optionally substituted chain alkenyl group.

[0135] In the above formulas (ca-r-1) to (ca-r-10), R' 201 are each independently a hydrogen atom, an optionally substituted cyclic group, an optionally substituted chain alkyl group, or an optionally substituted chain alkenyl group.

[0136] Optionally substituted cyclic groups: The cyclic group is preferably a cyclic hydrocarbon group, and the cyclic hydrocarbon group may be an aromatic hydrocarbon group or a cyclic aliphatic hydrocarbon group. An aliphatic hydrocarbon group means a hydrocarbon group that does not have aromaticity. Furthermore, the aliphatic hydrocarbon group may be saturated or unsaturated, and is usually preferably saturated.

[0137] R' 201The aromatic hydrocarbon group in the formula (I) is a hydrocarbon group having an aromatic ring. The aromatic hydrocarbon group preferably has 3 to 30 carbon atoms, more preferably 5 to 30, even more preferably 5 to 20, particularly preferably 6 to 15, and most preferably 6 to 10. However, the number of carbon atoms does not include the number of carbon atoms in the substituent. R' 201 Specific examples of the aromatic ring possessed by the aromatic hydrocarbon group in the above formula include benzene, fluorene, naphthalene, anthracene, phenanthrene, biphenyl, and aromatic heterocycles in which some of the carbon atoms constituting these aromatic rings are substituted with heteroatoms, or rings in which some of the hydrogen atoms constituting these aromatic rings or aromatic heterocycles are substituted with oxo groups, etc. Examples of the heteroatom in the aromatic heterocycle include an oxygen atom, a sulfur atom, and a nitrogen atom. R' 201 Specific examples of the aromatic hydrocarbon group in the formula (I) include a group in which one hydrogen atom has been removed from the aromatic ring (an aryl group: for example, a phenyl group, a naphthyl group, or an anthracenyl group); a group in which one hydrogen atom of the aromatic ring has been substituted with an alkylene group (for example, an arylalkyl group such as a benzyl group, a phenethyl group, a 1-naphthylmethyl group, a 2-naphthylmethyl group, a 1-naphthylethyl group, or a 2-naphthylethyl group); a group in which one hydrogen atom has been removed from a ring in which some of the hydrogen atoms constituting the aromatic ring have been substituted with an oxo group or the like (for example, anthraquinone); and a group in which one hydrogen atom has been removed from an aromatic heterocycle (for example, 9H-thioxanthene or 9H-thioxanthen-9-one). The alkylene group (the alkyl chain in the arylalkyl group) preferably has 1 to 4 carbon atoms, more preferably 1 to 2, and particularly preferably 1.

[0138] R' 201 The cyclic aliphatic hydrocarbon group in the formula (I) is an aliphatic hydrocarbon group containing a ring in the structure. Examples of aliphatic hydrocarbon groups that contain a ring in their structure include alicyclic hydrocarbon groups (groups in which one hydrogen atom has been removed from an aliphatic hydrocarbon ring), groups in which an alicyclic hydrocarbon group is bonded to the end of a straight-chain or branched-chain aliphatic hydrocarbon group, and groups in which an alicyclic hydrocarbon group is interposed in the middle of a straight-chain or branched-chain aliphatic hydrocarbon group. The alicyclic hydrocarbon group preferably has 3 to 20 carbon atoms, and more preferably 3 to 12 carbon atoms. The alicyclic hydrocarbon group may be a polycyclic group or a monocyclic group. The monocyclic alicyclic hydrocarbon group is preferably a group in which one or more hydrogen atoms have been removed from a monocycloalkane. The monocycloalkane preferably has 3 to 6 carbon atoms, and specific examples include cyclopentane and cyclohexane. The polycyclic alicyclic hydrocarbon group is preferably a group in which one or more hydrogen atoms have been removed from a polycycloalkane, and the polycycloalkane preferably has 7 to 30 carbon atoms. Among these, the polycycloalkane is more preferably a polycycloalkane having a bridged ring polycyclic skeleton, such as adamantane, norbornane, isobornane, tricyclodecane, or tetracyclododecane; or a polycycloalkane having a fused ring polycyclic skeleton, such as a cyclic group having a steroid skeleton.

[0139] Among them, R' 201 The cyclic aliphatic hydrocarbon group in is preferably a group in which one or more hydrogen atoms have been removed from a monocycloalkane or a polycycloalkane, more preferably a group in which one hydrogen atom has been removed from a polycycloalkane, particularly preferably an adamantyl group or a norbornyl group, and most preferably an adamantyl group.

[0140] The linear or branched aliphatic hydrocarbon group which may be bonded to the alicyclic hydrocarbon group preferably has 1 to 10 carbon atoms, more preferably 1 to 6 carbon atoms, even more preferably 1 to 4 carbon atoms, and most preferably 1 to 3 carbon atoms. As the straight-chain aliphatic hydrocarbon group, a straight-chain alkylene group is preferred, and specific examples include a methylene group [-CH2-], an ethylene group [-(CH2)2-], a trimethylene group [-(CH2)3-], a tetramethylene group [-(CH2)4-], and a pentamethylene group [-(CH2)5-]. The branched aliphatic hydrocarbon group is preferably a branched alkylene group, and specific examples thereof include alkyl alkylene groups such as alkylmethylene groups such as -CH(CH3)-, -CH(CH2CH3)-, -C(CH3)2-, -C(CH3)(CH2CH3)-, -C(CH3)(CH2CH2CH3)-, and -C(CH2CH3)2-; alkylethylene groups such as -CH(CH3)CH2-, -CH(CH3)CH(CH3)-, -C(CH3)2CH2-, -CH(CH2CH3)CH2-, and -C(CH2CH3)2-CH2-; alkyl trimethylene groups such as -CH(CH3)CH2CH2- and -CH2CH(CH3)CH2-; and alkyl tetramethylene groups such as -CH(CH3)CH2CH2CH2- and -CH2CH(CH3)CH2CH2-. The alkyl group in the alkylalkylene group is preferably a linear alkyl group having 1 to 5 carbon atoms.

[0141] An optionally substituted chain alkyl group: R' 201 The chain alkyl group may be either a straight chain or a branched chain. The linear alkyl group preferably has 1 to 20 carbon atoms, more preferably 1 to 15 carbon atoms, and most preferably 1 to 10. Specific examples include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, a nonyl group, a decanyl group, an undecyl group, a dodecyl group, a tridecyl group, an isotridecyl group, a tetradecyl group, a pentadecyl group, a hexadecyl group, an isohexadecyl group, a heptadecyl group, an octadecyl group, a nonadecyl group, an icosyl group, a heneicosyl group, and a docosyl group. The branched alkyl group preferably has 3 to 20 carbon atoms, more preferably 3 to 15 carbon atoms, and most preferably 3 to 10. Specific examples include a 1-methylethyl group, a 1-methylpropyl group, a 2-methylpropyl group, a 1-methylbutyl group, a 2-methylbutyl group, a 3-methylbutyl group, a 1-ethylbutyl group, a 2-ethylbutyl group, a 1-methylpentyl group, a 2-methylpentyl group, a 3-methylpentyl group, and a 4-methylpentyl group.

[0142] An optionally substituted chain alkenyl group: R' 201 The chain alkenyl group may be either linear or branched, and preferably has 2 to 10 carbon atoms, more preferably 2 to 5, even more preferably 2 to 4, and particularly preferably 3. Examples of the linear alkenyl group include a vinyl group, a propenyl group (allyl group), and a butynyl group. Examples of the branched alkenyl group include a 1-methylvinyl group, a 2-methylvinyl group, a 1-methylpropenyl group, and a 2-methylpropenyl group. Of the chain alkenyl groups mentioned above, linear alkenyl groups are preferred, vinyl groups and propenyl groups are more preferred, and vinyl groups are particularly preferred.

[0143] R' 201 Examples of the substituent in the cyclic group, chain alkyl group or alkenyl group include an alkoxy group, a halogen atom, a halogenated alkyl group, a hydroxyl group, a carbonyl group, a nitro group, an amino group, an oxo group, the above-mentioned R' 201 Examples of the groups include a cyclic group, an alkylcarbonyl group, and a thienylcarbonyl group.

[0144] Among them, R' 201 is preferably a cyclic group which may have a substituent, or a chain alkyl group which may have a substituent.

[0145] R 201 ~R 203 , R 206 ~R 207 , R 211~R 212 When they are bonded to each other to form a ring together with the sulfur atom in the formula, they may not contain a heteroatom such as a sulfur atom, an oxygen atom, or a nitrogen atom, or a carbonyl group, -SO-, -SO2-, -SO3-, -COO-, -CONH-, or -N(R N )-(applicable R N is an alkyl group having 1 to 5 carbon atoms.) The ring formed is preferably a 3- to 10-membered ring, including the sulfur atom, and particularly preferably a 5- to 7-membered ring, inclusive of the sulfur atom. Specific examples of the ring formed include a thiophene ring, a thiazole ring, a benzothiophene ring, a thianthrene ring, a benzothiophene ring, a dibenzothiophene ring, a 9H-thioxanthene ring, a thioxanthone ring, a thianthrene ring, a phenoxathiin ring, a tetrahydrothiophenium ring, and a tetrahydrothiopyranium ring.

[0146] In the formula (ca-3), R 208 ~R 209 each independently represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, preferably a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and when they are alkyl groups, they may be bonded to each other to form a ring.

[0147] In the formula (ca-3), R 210 is an optionally substituted aryl group, an optionally substituted alkyl group, an optionally substituted alkenyl group, or an optionally substituted -SO2- containing cyclic group. R 210 The aryl group in the formula (I) includes an unsubstituted aryl group having 6 to 20 carbon atoms, and a phenyl group or a naphthyl group is preferred. R 210 The alkyl group in the formula (I) is preferably a chain or cyclic alkyl group having 1 to 30 carbon atoms. R 210 The alkenyl group in the formula (I) preferably has 2 to 10 carbon atoms.

[0148] In the formula (ca-4) and formula (ca-5), Y 201 each independently represents an arylene group, an alkylene group, or an alkenylene group. Y 201 The arylene group in R' 201 Examples of the aromatic hydrocarbon group in the above formula include groups in which one hydrogen atom has been removed from the aryl groups exemplified above. Y 201 The alkylene group and alkenylene group in R' 201 Examples of the chain alkyl group and chain alkenyl group include groups in which one hydrogen atom has been removed from the groups exemplified above as the chain alkyl group and chain alkenyl group.

[0149] In the above formulas (ca-4) and (ca-5), x is 1 or 2. W 201 is an (x+1)-valent, i.e., a divalent or trivalent linking group. W 201 The divalent linking group in the formula (A1-1) is preferably a divalent hydrocarbon group which may have a substituent. EP The same groups as the optionally substituted divalent hydrocarbon groups exemplified by W are preferred. 201 The divalent linking group in may be linear, branched, or cyclic, and is preferably cyclic. Among them, a group in which two carbonyl groups are combined at both ends of an arylene group, or a group consisting of an arylene group alone is preferred. Examples of the arylene group include a phenylene group and a naphthylene group, and a phenylene group is particularly preferred. W 201 The trivalent linking group in 201 Examples of the divalent linking group include a group in which one hydrogen atom has been removed from the divalent linking group shown in the formula (1), and a group in which the divalent linking group is further bonded to the divalent linking group shown in the formula (1). 201 The trivalent linking group in the formula (I) is preferably a group in which two carbonyl groups are bonded to an arylene group.

[0150] Specific examples of suitable cations represented by the formula (ca-1) include cations represented by the following formulas (ca-1-1) to (ca-1-24).

[0151] [ka]

[0152] [ka] [In the formula, R” 201 is a hydrogen atom or a substituent. The substituent includes the above-mentioned R 201 ~R 207 and R 210 ~R 212 The substituents are the same as those exemplified as the substituents that may be possessed by the group

[0153] As the cation represented by the formula (ca-1), cations represented by the following general formulas (ca-1-25) to (ca-1-35) are also preferred.

[0154] [ka]

[0155] [ka] [In the formula, R' 211 is an alkyl group. hal is a hydrogen atom or a halogen atom.

[0156] As the cation represented by the formula (ca-1), cations represented by the following chemical formulas (ca-1-36) to (ca-1-48) are also preferred.

[0157] [ka]

[0158] As the cation represented by the formula (ca-1), cations having a benzoylphenyl group represented by the following chemical formulas (ca-1-49) to (ca-1-54) are also preferred.

[0159] [ka]

[0160] Specific examples of suitable cations represented by the formula (ca-2) include diphenyliodonium cation, bis(4-tert-butylphenyl)iodonium cation, and the like.

[0161] Specific examples of suitable cations represented by the formula (ca-3) include cations represented by the following formulas (ca-3-1) to (ca-3-6).

[0162] [ka]

[0163] Specific examples of suitable cations represented by the formula (ca-4) include cations represented by the following formulas (ca-4-1) to (ca-4-2).

[0164] [ka]

[0165] As the cation represented by the formula (ca-5), cations represented by the following general formulas (ca-5-1) to (ca-5-3) are also preferred.

[0166] [ka] [In the formula, R' 212 R' is an alkyl group or a hydrogen atom. 211 is an alkyl group.

[0167] Among the above, the cation part [(Q q+ ) 1 / q] is preferably a cation represented by general formula (ca-1), more preferably a cation represented by each of formulas (ca-1-1) to (ca-1-54), and even more preferably a cation represented by each of formulas (ca-1-29), (ca-1-48), and (ca-1-49) to (ca-1-54).

[0168] <Other cationic polymerization initiators> Examples of cationic polymerization initiators other than the component (I1) include compounds represented by the following general formula (I2-1) or (I2-2) (hereinafter referred to as "component (I2)"); and compounds represented by the following general formula (I3-1) or (I3-2) (hereinafter referred to as "component (I3)").

[0169] (I2) Ingredients: The component (I2) is a compound represented by the following general formula (I2-1) or (I2-2). The component (I2) generates a relatively strong acid upon exposure, and therefore, when a photosensitive composition containing the component (I2) is used, sufficient sensitivity is obtained and a good pattern is formed.

[0170] [ka] [In the formula, R b05 is a fluorine atom or a fluorinated alkyl group which may have a substituent. b05 may be the same or different from each other. q is an integer of 1 or more, and Q q+ is a q-valent organic cation.

[0171] [ka] [In the formula, R b06 is a fluorine atom or a fluorinated alkyl group which may have a substituent. b06 may be the same or different from each other. q is an integer of 1 or more, and Q q+ is a q-valent organic cation.

[0172] Anion section In the above formula (I2-1), R b05 is a fluorine atom or a fluorinated alkyl group which may have a substituent. b05 may be the same as or different from each other. R b05 The fluorinated alkyl group in the formula (I) preferably has 1 to 10 carbon atoms, more preferably 1 to 8, and even more preferably 1 to 5. Specific examples include alkyl groups having 1 to 5 carbon atoms in which some or all of the hydrogen atoms have been substituted with fluorine atoms. Among them, R b05 is preferably a fluorine atom or a fluorinated alkyl group having 1 to 5 carbon atoms, more preferably a fluorine atom or a perfluoroalkyl group having 1 to 5 carbon atoms, and further preferably a fluorine atom, a trifluoromethyl group or a pentafluoroethyl group.

[0173] The anion moiety of the compound represented by formula (I2-1) is preferably represented by the following general formula (b0-2a).

[0174] [ka] [In the formula, R bf05 nb is a fluorinated alkyl group which may have a substituent. 1 is an integer between 1 and 5.

[0175] In formula (b0-2a), R bf05 The optionally substituted fluorinated alkyl group in R b05 The same applies to the optionally substituted fluorinated alkyl groups listed in the above. In formula (b0-2a), nb 1 is preferably an integer of 1 to 4, more preferably an integer of 2 to 4, and most preferably 3.

[0176] In the above formula (I2-2), R b06 is a fluorine atom or a fluorinated alkyl group which may have a substituent. b06may be the same as or different from each other. R b06 The fluorinated alkyl group in the formula (I) preferably has 1 to 10 carbon atoms, more preferably 1 to 8, and even more preferably 1 to 5. Specific examples include alkyl groups having 1 to 5 carbon atoms in which some or all of the hydrogen atoms have been substituted with fluorine atoms. Among them, R b06 As the alkyl group, a fluorine atom or a fluorinated alkyl group having 1 to 5 carbon atoms is preferred, a fluorine atom or a perfluoroalkyl group having 1 to 5 carbon atoms is more preferred, and a fluorine atom is even more preferred.

[0177] Cation part In formula (I2-1) and formula (I2-2), q is an integer of 1 or more, and Q q+ is a q-valent organic cation. This Q q+ As the Q in the above formula (I1), q+ Among them, cations represented by general formula (ca-1) are preferred, and cations represented by formulas (ca-1-1) to (ca-1-54) are more preferred.

[0178] (I3) Ingredients: The component (I3) is a compound represented by the following general formula (I3-1) or (I3-2).

[0179] [ka] [In the formula, R b11 ~R b12 is a cyclic group which may have a substituent other than a halogen atom, a chain alkyl group which may have a substituent other than a halogen atom, or a chain alkenyl group which may have a substituent other than a halogen atom. m is an integer of 1 or more, and M m+ are each independently an m-valent organic cation.

[0180] {Component (I3-1)} Anion section In formula (I3-1), Rb12 is a cyclic group which may have a substituent other than a halogen atom, a chain alkyl group which may have a substituent other than a halogen atom, or a chain alkenyl group which may have a substituent other than a halogen atom, and R' 201 Among the cyclic groups, chain alkyl groups and chain alkenyl groups in the explanation of (1), those which have no substituent or those which have a substituent other than a halogen atom are exemplified. R b12 The alkyl group is preferably a chain alkyl group which may have a substituent other than a halogen atom, or an aliphatic cyclic group which may have a substituent other than a halogen atom. The chain alkyl group preferably has 1 to 10 carbon atoms, and more preferably 3 to 10. The aliphatic cyclic group is preferably a group in which one or more hydrogen atoms have been removed from adamantane, norbornane, isobornane, tricyclodecane, tetracyclododecane, or the like (which may have a substituent other than a halogen atom); or a group in which one or more hydrogen atoms have been removed from camphor, or the like. R b12 The hydrocarbon group may have a substituent other than a halogen atom, and examples of the substituent include R b11 Examples of the substituents include those similar to the substituents other than halogen atoms that may be contained in the hydrocarbon group (aromatic hydrocarbon group, aliphatic cyclic group, chain alkyl group) in the above formula. The phrase "may have a substituent other than a halogen atom" as used herein not only excludes cases where a substituent consists of only halogen atoms, but also excludes cases where a substituent contains at least one halogen atom (for example, when the substituent is a fluorinated alkyl group).

[0181] Preferred examples of the anion moiety of the component (I3-1) are shown below.

[0182] [ka]

[0183] Cation part In formula (I3-1), M m+ is an m-valent organic cation. M m+ Suitable examples of the organic cation include the same cations as those represented by the general formulas (ca-1) to (ca-5) above, and among these, the cation represented by the general formula (ca-1) above is more preferred. 201 , R 202 , R 203 A sulfonium cation in which at least one of the above is an organic group having 16 or more carbon atoms (aryl group, heteroaryl group, alkyl group, or alkenyl group) which may have a substituent is particularly preferred because it improves resolution and roughness characteristics. The substituents that the organic group may have are the same as those described above, and include an alkyl group, a halogen atom, a halogenated alkyl group, a carbonyl group, a cyano group, an amino group, an oxo group (═O), an aryl group, and groups represented by the above formulas (ca-r-1) to (ca-r-10). The number of carbon atoms in the organic group (aryl group, heteroaryl group, alkyl group, or alkenyl group) is preferably 16 to 25, more preferably 16 to 20, and particularly preferably 16 to 18. m+ Suitable organic cations include those represented by the above formulas (ca-1-25), (ca-1-26), (ca-1-28) to (ca-1-36), (ca-1-38), (ca-1-46), and (ca-1-47), and among these, the cation represented by the above formula (ca-1-29) is particularly preferred.

[0184] {Component (I3-2)} Anion section In formula (I3-2), R b11 is a cyclic group which may have a substituent other than a halogen atom, a chain alkyl group which may have a substituent other than a halogen atom, or a chain alkenyl group which may have a substituent other than a halogen atom, and R' 201Among the cyclic groups, chain alkyl groups and chain alkenyl groups in the explanation of (1), those which have no substituent or those which have a substituent other than a halogen atom are exemplified.

[0185] Among these, R b11 As the substituent, an aromatic hydrocarbon group which may have a substituent other than a halogen atom, an aliphatic cyclic group which may have a substituent other than a halogen atom, or a chain alkyl group which may have a substituent other than a halogen atom is preferred. Examples of the substituent which these groups may have include a hydroxyl group, an oxo group, an alkyl group, an aryl group, a lactone-containing cyclic group, an ether bond, an ester bond, or a combination thereof. When an ether bond or an ester bond is contained as a substituent, it may be connected via an alkylene group, and in this case, the substituent is preferably a linking group represented by each of the following general formulas (y-al-1) to (y-al-7). In the following general formulas (y-al-1) to (y-al-7), R in the above formula (I3-2) b11 The bond to V' in the following general formulas (y-al-1) to (y-al-7) is 101 is.

[0186] [ka] [In the formula, V' 101 V' is a single bond or an alkylene group having 1 to 5 carbon atoms. 102 is a divalent saturated hydrocarbon group having 1 to 30 carbon atoms.]

[0187] V' 102 The divalent saturated hydrocarbon group in is preferably an alkylene group having 1 to 30 carbon atoms, more preferably an alkylene group having 1 to 10 carbon atoms, and even more preferably an alkylene group having 1 to 5 carbon atoms.

[0188] V' 101 and V' 102The alkylene group in may be a straight-chain alkylene group or a branched-chain alkylene group, and is preferably a straight-chain alkylene group. V' 101 and V' 102 Specific examples of the alkylene group in the formula (I) include a methylene group [-CH2-]; alkylmethylene groups such as -CH(CH3)-, -CH(CH2CH3)-, -C(CH3)2-, -C(CH3)(CH2CH3)-, -C(CH3)(CH2CH2CH3)-, and -C(CH2CH3)2-; an ethylene group [-CH2CH2-]; -CH(CH3)CH2-, -CH(CH3)CH(CH3)-, -C(CH3)2CH2-, and -CH(CH2CH3)CH2 -, etc.; a trimethylene group (n-propylene group) [-CH2CH2CH2-]; alkyl trimethylene groups such as -CH(CH3)CH2CH2- and -CH2CH(CH3)CH2-; a tetramethylene group [-CH2CH2CH2CH2-]; alkyl tetramethylene groups such as -CH(CH3)CH2CH2CH2- and -CH2CH(CH3)CH2CH2-; and a pentamethylene group [-CH2CH2CH2CH2CH2-]. Also, V' 101 or V' 102 In the above, some methylene groups in the alkylene group may be substituted with a divalent aliphatic cyclic group having 5 to 10 carbon atoms. The aliphatic cyclic group is represented by R' 201 A divalent group obtained by removing one hydrogen atom from a cyclic aliphatic hydrocarbon group (a monocyclic alicyclic hydrocarbon group or a polycyclic alicyclic hydrocarbon group) is preferred, and a cyclohexylene group, a 1,5-adamantylene group or a 2,6-adamantylene group is more preferred.

[0189] The aromatic hydrocarbon group is more preferably a phenyl group or a naphthyl group. The aliphatic cyclic group is more preferably a group in which one or more hydrogen atoms have been removed from a polycycloalkane such as adamantane, norbornane, isobornane, tricyclodecane, or tetracyclododecane. The chain alkyl group preferably has 1 to 10 carbon atoms, and specific examples thereof include straight-chain alkyl groups such as a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, a nonyl group, and a decyl group; and branched-chain alkyl groups such as a 1-methylethyl group, a 1-methylpropyl group, a 2-methylpropyl group, a 1-methylbutyl group, a 2-methylbutyl group, a 3-methylbutyl group, a 1-ethylbutyl group, a 2-ethylbutyl group, a 1-methylpentyl group, a 2-methylpentyl group, a 3-methylpentyl group, and a 4-methylpentyl group.

[0190] R b11 As the aryl group, a cyclic group which may have a substituent other than a halogen atom is preferred. Preferred examples of the anion moiety of the component (I3-2) are shown below.

[0191] [ka]

[0192] Cation part In formula (I3-2), M m+ is an m-valent organic cation, and M in the formula (I3-1) m+ is the same as:

[0193] Furthermore, from the viewpoints of increasing the elasticity of the photosensitive resin film and facilitating the formation of a fine structure without residue, the component (I) is preferably a cationic polymerization initiator that generates an acid with a pKa (acid dissociation constant) of -5 or less upon exposure. By using a cationic polymerization initiator that generates an acid with a pKa of more preferably -6 or less, and even more preferably -8 or less, it becomes possible to obtain high sensitivity to exposure. The lower limit of the pKa of the acid generated by the component (I) is preferably -15 or more. By using a cationic polymerization initiator that generates an acid with such a suitable pKa, high sensitivity can be easily achieved. Here, "pKa (acid dissociation constant)" refers to a commonly used index indicating the acid strength of a substance of interest. In this specification, pKa is a value at a temperature of 25°C. The pKa value can be determined by measurement using known methods. Alternatively, a calculated value using known software such as "ACD / Labs" (trade name, manufactured by Advanced Chemistry Development) can also be used.

[0194] As the component (I), one type may be used alone, or two or more types may be used in combination. In the photosensitive composition of this embodiment, from the viewpoint of easily suppressing corrosion of the interdigital electrodes, it is preferable to use a compound (component (I1)) comprising an anion moiety containing a borate anion and a cation moiety as the component (I), and it is more preferable to use an onium borate salt.

[0195] In the photosensitive composition of this embodiment, the content of component (I) is preferably 0.5 to 5 parts by mass, more preferably 1 to 5 parts by mass, even more preferably 1 to 3 parts by mass, and particularly preferably 1 to 2 parts by mass, relative to 100 parts by mass of component (A). When the content of component (I) is equal to or greater than the lower limit of the preferred range, sufficient sensitivity is obtained, and the lithography characteristics of the pattern are further improved. In addition, the strength of the photosensitive resin film is further increased. On the other hand, when the content is equal to or less than the upper limit of the preferred range, sensitivity is appropriately controlled, and a pattern with a good shape is easily obtained.

[0196] <Other ingredients> The photosensitive composition of the present embodiment may contain other components, as needed, in addition to the components (A) and (I). If desired, the photosensitive composition of the present embodiment may contain miscible additives, such as metal oxides, sensitizer components, silane coupling agents, additional resins for improving film performance, dissolution inhibitors, basic compounds, plasticizers, stabilizers, colorants, and antihalation agents.

[0197] The photosensitive composition according to the present embodiment described above is used to produce the hollow structure according to the above-mentioned embodiment, and the photosensitive composition according to the present embodiment is a material for at least one of the side walls and the top plate portion constituting the hollow structure. When the SiN layer of the Si substrate is evaluated by X-ray photoelectron spectroscopy in the above-mentioned [Method for evaluating outgassing], the ratio of carbon to silicon (C / Si) is less than 0.2 and the detected amount of fluorine is 0.3 atm% or less.

[0198] A preferred embodiment of such a photosensitive composition comprises an epoxy group-containing compound and a cationic polymerization initiator, wherein the epoxy group-containing compound comprises a tri- or higher functional epoxy group-containing compound, and the content of a bifunctional epoxy monomer is 2 mass% or less based on the total mass of the tri- or higher functional epoxy group-containing compound and the bifunctional epoxy monomer, and the cationic polymerization initiator comprises a compound comprising an anion moiety containing a borate anion and a cation moiety.

[0199] A more preferred embodiment of the photosensitive composition comprises an epoxy group-containing compound and a cationic polymerization initiator, wherein the epoxy group-containing compound comprises a trisphenol-type polyglycidyl ether compound having three or more epoxy groups in one molecule, the cationic polymerization initiator comprises a compound consisting of an anion moiety containing a borate anion and a cationic moiety, the content of the cationic polymerization initiator is 1 part by mass or more and 5 parts by mass or less per 100 parts by mass of the epoxy group-containing compound, and in step (1-3) of the above-mentioned [Method for evaluating outgassing], the exposure dose is 10 mJ / cm 2 More than 2000mJ / cm 2 When performing exposure with an exposure dose of 500 mJ / cm or less, the exposure dose is preferably 500 mJ / cm 2 More than 1600mJ / cm 2 When performing exposure to the following conditions, the C / Si ratio is less than 0.2 and the detected amount of fluorine is 0.3 atm % or less.

[0200] Alternatively, a more preferred embodiment of the photosensitive composition is a composition containing an epoxy group-containing compound and a cationic polymerization initiator, wherein the epoxy group-containing compound contains a novolac epoxy resin, the cationic polymerization initiator contains a compound consisting of an anion moiety containing a borate anion and a cationic moiety, the content of the cationic polymerization initiator is 1 part by mass or more and 5 parts by mass or less per 100 parts by mass of the epoxy group-containing compound, and in step (1-3) of the above [Method for evaluating outgassing], the exposure dose is 10 mJ / cm 2 More than 2000mJ / cm 2 When performing exposure with an exposure dose of 50 mJ / cm or less, the exposure dose is preferably 50 mJ / cm 2 More than 500mJ / cm 2 When performing exposure to the following conditions, the C / Si ratio is less than 0.2 and the detected amount of fluorine is 0.3 atm % or less. The novolac type epoxy resin may include a bisphenol novolac type epoxy resin, and the content of the bisphenol epoxy monomer may be 2 mass % or less based on the total mass of the bisphenol novolac type epoxy resin and the bisphenol epoxy monomer. Alternatively, the novolac type epoxy resin is preferably a phenol novolac type epoxy resin or a cresol novolac type epoxy resin, and more preferably a cresol novolac type epoxy resin.

[0201] (Method for producing photosensitive composition) A method for producing a photosensitive composition according to one embodiment of the present invention is a method for producing a hollow structure including: a device substrate including a substrate, comb-shaped electrodes provided on the substrate, and a SiN layer formed on the substrate so as to cover the comb-shaped electrodes; side walls formed on the device substrate so as to surround the comb-shaped electrodes; and a top plate portion formed on the side walls so as to face the device substrate, wherein the photosensitive composition is a material for at least one of the side walls and the top plate portion, and the method includes a step (hereinafter also referred to as a "selection step") of selecting photosensitive compositions that, when evaluated on the SiN layer of the Si substrate by X-ray photoelectron spectroscopy according to the "Method for Evaluating Outgassing" described below, exhibit a carbon to silicon ratio (C / Si) of less than 0.2 and a detected amount of fluorine of 0.3 atm% or less.

[0202] [Outgassing evaluation method] Step (1-1'): A photosensitive composition is applied onto a release polyethylene terephthalate (PET) film using an applicator, and then dried in an oven at 70°C for 10 minutes to form a photosensitive composition layer with a thickness of 20 μm. Step (1-2): Next, the photosensitive composition layer is attached to the Si substrate so that the photosensitive composition layer and the Si substrate are in contact with each other, using a laminator under the following conditions: 80°C, pressure 0.3 MPa, and speed 0.5 m / min. Step (1-3): Next, the release PET film is peeled off, and then the photosensitive composition layer is exposed using a ghi broadband exposure machine to obtain a test substrate. Step (2): Separately, on a Si substrate having a SiN layer on the outermost surface, a 50 μm thick polyimide film with a heat resistance of 300°C or higher, with the center cut out, is placed on the outer peripheral edge of the SiN layer on the Si substrate. Step (3): Next, the test substrate is placed on the polyimide film so that the photosensitive composition layer and the SiN layer face each other. Step (4): Next, the substrate is baked. The baking conditions are as follows: the substrate is heated on a hot plate at 90°C for 5 minutes, then heated to 200°C over 15 minutes, and held at 200°C for 1 hour. The substrate is then removed from the hot plate and allowed to cool. Step (5): After cooling, the test substrate and the polyimide film are removed, and then the portion of the SiN layer that was facing the photosensitive composition layer but is not in contact with the polyimide film is evaluated by X-ray photoelectron spectroscopy. Step (6): Using an X-ray photoelectron spectrometer, the composition ratios of C / Si and F are calculated from the spectra of C1s for carbon (C), Si2p for silicon (Si), and F1s for fluorine (F).

[0203] <Sorting process> In one embodiment of the selection process, the above steps (1-1′) to (6) are performed in this order [method for evaluating outgassing] to select photosensitive compositions that, when evaluated on a SiN layer of a Si substrate by X-ray photoelectron spectroscopy, have a carbon to silicon ratio (C / Si) of less than 0.2 and a detected amount of fluorine of 0.3 atm% or less. In one embodiment of the method for producing a photosensitive composition, the photosensitive composition prepared in the step (1-1') up to the selection step is used, and the steps (1-1') to (6) are carried out to evaluate the detected amounts of C / Si and fluorine. The operations from step (1-1′) to step (6) in the selection step of this embodiment are the same as those in one embodiment of the outgassing evaluation method described above in (Photosensitive composition), in which “step (1-1), step (1-2), step (1-3), step (2), step (3), step (4), step (5), and step (6) are performed in this order.”

[0204] In the photosensitive composition manufacturing method of this embodiment, the selection step selects photosensitive compositions with a C / Si ratio of less than 0.2 and a detected fluorine content of 0.3 atm% or less. When the selected photosensitive composition is used to manufacture a hollow structure, the generation of outgassing originating from the photosensitive composition is suppressed during the post-exposure thermal curing process (post-exposure bake, cure). In microelectronic devices utilizing hollow structures manufactured using this photosensitive composition, negative frequency shifts are unlikely to occur. In addition, the use of the selected photosensitive composition can easily suppress corrosion of interdigital electrodes. That is, the photosensitive composition manufacturing method of this embodiment can produce a photosensitive composition useful for manufacturing hollow structures with suppressed outgassing.

[0205] (Method for inspecting photosensitive composition) A photosensitive composition inspection method according to one embodiment of the present invention is a method for inspecting a photosensitive composition for producing a hollow structure including a device substrate including a substrate, a comb-shaped electrode provided on the substrate, and a SiN layer formed on the substrate so as to cover the comb-shaped electrode, side walls formed on the device substrate so as to surround the comb-shaped electrode, and a top plate portion formed on the side walls so as to face the device substrate, wherein the photosensitive composition is a material for at least one of the side walls and the top plate portion, and the carbon to silicon ratio (C / Si) and the amount of fluorine detected on the SiN layer of the Si substrate are evaluated by X-ray photoelectron spectroscopy in the "Method for evaluating outgassing" described below.

[0206] [Outgassing evaluation method] Procedure (1-1"): A photosensitive composition is applied onto a release polyethylene terephthalate (PET) film using an applicator, and dried in an oven at 70°C for 10 minutes to form a photosensitive composition layer with a thickness of 20 μm. Step (1-2): Next, the photosensitive composition layer is attached to the Si substrate so that the photosensitive composition layer and the Si substrate are in contact with each other, using a laminator under the following conditions: 80°C, pressure 0.3 MPa, and speed 0.5 m / min. Step (1-3): Next, the release PET film is peeled off, and then the photosensitive composition layer is exposed using a ghi broadband exposure machine to obtain a test substrate. Step (2): Separately, on a Si substrate having a SiN layer on the outermost surface, a 50 μm thick polyimide film with a heat resistance of 300°C or higher, with the center cut out, is placed on the outer peripheral edge of the SiN layer on the Si substrate. Step (3): Next, the test substrate is placed on the polyimide film so that the photosensitive composition layer and the SiN layer face each other. Step (4): Next, the substrate is baked. The baking conditions are as follows: the substrate is heated on a hot plate at 90°C for 5 minutes, then heated to 200°C over 15 minutes, and held at 200°C for 1 hour. The substrate is then removed from the hot plate and allowed to cool. Step (5): After cooling, the test substrate and the polyimide film are removed, and then the portion of the SiN layer that was facing the photosensitive composition layer but is not in contact with the polyimide film is evaluated by X-ray photoelectron spectroscopy. Step (6): Using an X-ray photoelectron spectrometer, the composition ratios of C / Si and F are calculated from the spectra of C1s for carbon (C), Si2p for silicon (Si), and F1s for fluorine (F).

[0207] In one embodiment of the method for inspecting a photosensitive composition, the above-mentioned steps (1-1") to (6) are performed in this order [method for evaluating outgassing], and the carbon to silicon ratio (C / Si) and the amount of fluorine detected on the SiN layer of the Si substrate are evaluated by X-ray photoelectron spectroscopy. In one embodiment of the photosensitive composition inspection method of the present embodiment, in the step (1-1"), any photosensitive composition is used, and the steps (1-1") to (6) are carried out to evaluate the detected amounts of C / Si and fluorine. The operations from step (1-1") to step (6) in the inspection method of this embodiment are the same as "the embodiment in which step (1-1), step (1-2), step (1-3), step (2), step (3), step (4), step (5), and step (6) are performed in this order" in one embodiment of the outgassing evaluation method described in the above (Photosensitive composition).

[0208] In the photosensitive composition inspection method of this embodiment, the carbon to silicon ratio (C / Si) and the detected amount of fluorine are evaluated on the SiN layer of the Si substrate after the operations from step (1-1") to step (6) have been performed. If the evaluation results show that the photosensitive composition has a C / Si of less than 0.2 and a detected amount of fluorine of 0.3 atm% or less, when this photosensitive composition is used to fabricate a hollow structure, outgassing originating from the photosensitive composition is suppressed in the thermal curing process (post-exposure bake, cure) after exposure. In microelectronic devices that utilize hollow structures fabricated with this photosensitive composition, frequency shifts to the negative side are unlikely to occur. In addition, if the photosensitive composition has a C / Si of less than 0.2 and a detected amount of fluorine of 0.3 atm% or less, corrosion of the interdigital electrodes can be easily suppressed by using this photosensitive composition. In other words, the photosensitive composition inspection method of this embodiment makes it possible to determine whether or not a photosensitive composition is useful for fabricating hollow structures in which outgassing is suppressed. [Example]

[0209] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

[0210] <Preparation of Photosensitive Composition> The components shown in Table 1 were mixed and dissolved, and then filtered using a PTFE filter (pore size 1 μm, manufactured by PALL Corporation) to prepare photosensitive compositions (1) to (15), each of which was a methyl ethyl ketone (MEK) solution with a solid content of 75% by mass.

[0211] [Table 1]

[0212] In Table 1, the abbreviations have the following meanings: The values ​​in brackets [ ] are the amounts of each component blended (parts by mass; solid content equivalent).

[0213] Epoxy group-containing compounds (A)-1: An epoxy group-containing compound represented by the following chemical formula (A1-2-1) (product name "TECHMORE VG-3101L", manufactured by Printec Co., Ltd.); content of bifunctional epoxy monomer: 0% by mass

[0214] [ka]

[0215] (A)-2: Bisphenol A novolac epoxy resin (trade name "jER-157S70", manufactured by Mitsubishi Chemical Corporation) represented by the following chemical formula (A1-1-p1): Weight average molecular weight: 2900, molecular weight dispersity: 4.23, epoxy equivalent: 220 g / eq.; content of difunctional epoxy monomer (bisphenol A diglycidyl ether) is 17% by mass based on the total mass of the trifunctional or higher epoxy group-containing compound and the difunctional epoxy monomer.

[0216] (A)-3: A bisphenol A novolac epoxy resin represented by the following chemical formula (A1-1-p2): This purified product was obtained by treating the bisphenol A novolac epoxy resin (trade name "jER-157S70", manufactured by Mitsubishi Chemical Corporation) using the purification method described below. It has a weight-average molecular weight of 4,500, a molecular weight dispersity of 2.17, and an epoxy equivalent of 226 g / eq. The content of a bifunctional epoxy monomer (bisphenol A diglycidyl ether) is 1.5% by mass relative to the total mass of the trifunctional or higher epoxy group-containing compound and the bifunctional epoxy monomer.

[0217] [Purification method 1st step] To 100 g (100 parts by mass) of the bisphenol A novolac epoxy resin (trade name "jER-157S70", manufactured by Mitsubishi Chemical Corporation), 300 g (300 parts by mass) of ethanol was added. The mixture was then heated to 70°C to melt the bisphenol A novolac epoxy resin (trade name "jER-157S70", manufactured by Mitsubishi Chemical Corporation) in the ethanol, thereby obtaining a mixed liquid. The resulting mixture was refluxed at 77° C. for 1 hour.

[0218] [Purification method 2nd step] The mixed liquid after refluxing was allowed to stand and cooled to 25° C. As a result, the molten resin in the mixed liquid solidified.

[0219] [Purification method 3rd step] The solidified material was separated from the remaining mixed liquid (ethanol etc.), and the solidified material was collected.

[0220] Next, the recovered solidified material was subjected to a further three times of the operation of carrying out Steps 1, 2, and 3 in this order. That is, the bisphenol A novolac epoxy resin (trade name "jER-157S70", manufactured by Mitsubishi Chemical Corporation) was subjected to a total of four times of the purification operation of carrying out Steps 1, 2, and 3 in this order.

[0221] The solidified material recovered after the four purification steps was then dried overnight at 100°C in a vacuum oven to obtain a purified bisphenol A novolac epoxy resin.

[0222] [ka]

[0223] [Measurement of weight-average molecular weight] The weight-average molecular weights of the bisphenol A novolac epoxy resin (trade name "jER-157S70", manufactured by Mitsubishi Chemical Corporation) before and after purification were measured by GPC (Gel Permeation Chromatography) under the following conditions. Device: HLC-8320 (Tosoh Corporation) Column: TSK Gel Super HM-N (3 columns connected) Eluent: tetrahydrofuran ·Flow rate: 0.6mL / min Column temperature: 40℃ Detector: RI Polystyrene Standards

[0224] GPC charts obtained from the signal of the RI detector are shown in FIGS. Figure 6 is a GPC chart of the bisphenol A novolac epoxy resin before purification, and Figure 7 is a GPC chart of the bisphenol A novolac epoxy resin after purification. The vertical axis represents the detection intensity, and the horizontal axis represents the retention time (min).

[0225] [Measurement of epoxy equivalent weight] Preparation of sodium carbonate-acetic acid solution: A sodium carbonate-acetic acid solution was prepared by the following procedure. First, approximately 10 g of sodium carbonate was placed in a crucible and heated in an electric furnace at 500°C for 1 hour. Next, the heated sodium carbonate was placed in a desiccator and left to stand for 1 hour until it reached room temperature. Next, approximately 2.5 to 3.0 g of sodium carbonate was weighed out after standing at room temperature and placed in a 500 mL measuring flask. Next, acetic acid was added until the total volume was 500 mL, and the sodium carbonate was dissolved.

[0226] Calculation of Factor F for Hydrogen Bromide-Acetic Acid Solution: Using a volumetric pipette, 5 mL of the prepared sodium carbonate / acetic acid solution was placed in a disposable cup. Next, about 30 mL of toluene was added to the disposable cup, followed by acetic acid, so that the electrodes were submerged. Next, a small amount of crystal violet-acetic acid solution was added as an indicator, and the resulting solution was titrated with hydrogen bromide-acetic acid solution. Next, the factor F of the hydrogen bromide-acetic acid solution was calculated using the following formula. S represents the mass (g) of sodium carbonate. P represents the purity (%) of sodium carbonate. A represents the amount (mL) of the hydrogen bromide-acetic acid solution added. F={S×(5 / 500)×(P / 100)} / (0.0053×A)

[0227] Measurement of oxirane oxygen concentration: Wg of the epoxy resin to be measured was placed in a disposable cup. Next, approximately 30 mL of toluene was added to the disposable cup. Next, acetic acid was added until the electrode was submerged. Next, a small amount of crystal violet / acetic acid solution was added as an indicator. The resulting solution was titrated with a hydrogen bromide / acetic acid solution. The endpoint was determined as the point at which the solution changed from blue to green and a large potential difference was observed. Next, the oxirane oxygen concentration X (%) was calculated using the following formula: T represents the amount (mL) of the hydrogen bromide-acetic acid solution added. X=(0.16×T×F) / W

[0228] Calculating the epoxy equivalent weight: The epoxy equivalent Y was calculated using the following formula. Y=(16×100) / X

[0229] (A)-4: o-Cresol novolac epoxy resin (trade name "YDCN-704", manufactured by Nippon Steel Chemical & Material Co., Ltd.) represented by the following chemical formula (A1-3); content of bifunctional epoxy monomer: 0 mass%

[0230] [ka]

[0231] cationic polymerization initiator (I)-1: A sulfonium salt represented by the following chemical formula (I-1): (I)-2: A sulfonium salt represented by the following chemical formula (I-2): (I)-3: A sulfonium salt represented by the following chemical formula (I-3): (I)-4: A sulfonium salt represented by the following chemical formula (I-4): (I)-5: A sulfonium salt represented by the following chemical formula (I-5):

[0232] [ka]

[0233] [ka]

[0234] <Outgassing test> The above photosensitive compositions (1) to (15) were used to carry out an outgassing test according to the following [Method for evaluating outgassing].

[0235] [Outgassing evaluation method] Procedure (1-1): A photosensitive composition dissolved in methyl ethyl ketone to adjust the solid content to 75% by mass was applied onto a release polyethylene terephthalate (PET) film using an applicator, and the film was dried in an oven at 70°C for 10 minutes to form a photosensitive composition layer with a thickness of 20 μm. Step (1-2): Next, the photosensitive composition layer was attached to the Si substrate so that the photosensitive composition layer was in contact with the Si substrate, using a laminator under the conditions of 80°C, pressure of 0.3 MPa, and speed of 0.5 m / min. Step (1-3): Next, the release PET film was peeled off, and then the photosensitive composition layer was exposed using a ghi broadband exposure machine to obtain a test substrate.

[0236] During the exposure, the exposure dose was such that a contact hole with a diameter of 50 μm could be formed. As shown in Tables 2-4, In the cases of Examples 1 to 3 and Comparative Examples 1 and 2, the i-line equivalent was 800 mJ / cm 2 , In the cases of Examples 4 to 6 and Comparative Examples 3 to 7, the i-line equivalent was 100 mJ / cm 2 , In the case of Comparative Example 8, the i-line equivalent was 2000 mJ / cm 2 , In the case of Example 7, the i-line equivalent is 1500 mJ / cm 2 , In the case of Comparative Example 9, the i-line equivalent was 400 mJ / cm 2 Each of the samples was exposed to 1000 kJ / cm².

[0237] Step (2): Separately, on a Si substrate having a SiN layer on the outermost surface, a 50 μm thick polyimide film with a heat resistance of 300°C or higher, with the center cut out, was placed on the outer peripheral edge of the SiN layer on the Si substrate. Here, Kapton (registered trademark) (a polyimide film manufactured by DuPont-Toray Co., Ltd.) was used as the polyimide film.

[0238] Step (3): Next, the test substrate was placed on the polyimide film so that the photosensitive composition layer and the SiN layer faced each other. Step (4): The substrate was then baked. The baking conditions were as follows: the substrate was heated on a hot plate at 90°C for 5 minutes, then heated to 200°C over 15 minutes, and held at 200°C for 1 hour. The substrate was then removed from the hot plate and allowed to cool.

[0239] Step (5): After cooling, the test substrate and the polyimide film were removed, and then the portion of the SiN layer facing the photosensitive composition layer but not in contact with the polyimide film was evaluated by X-ray photoelectron spectroscopy (XPS).

[0240] Step (6): Using XPS with an X-ray photoelectron spectrometer, the composition ratios of C / Si and F were calculated from the spectra of carbon (C) C1s, silicon (Si) Si2p, and fluorine (F) F1s, and the ratio of carbon to silicon (C / Si) and the detected amount of fluorine [atm%] were determined. The X-ray photoelectron spectrometer used was a K-Alpha X-ray photoelectron spectrometer manufactured by Thermo Fisher Scientific.

[0241] For each example, the carbon to silicon ratio (C / Si) and the detected amount of fluorine [atm %] determined by XPS are shown in Tables 2 to 4.

[0242] [Table 2]

[0243] [Table 3]

[0244] [Table 4]

[0245] [Evaluation of contact angle after outgassing test] In step (5) of the above-mentioned [Method for evaluating outgassing], a contact angle was measured when water was dropped onto the topmost SiN layer of the Si substrate at a portion where the polyimide film was not in contact, using a contact angle meter. The contact angle meter used was a DMo-501 manufactured by Kyowa Interface Science Co., Ltd. The contact angles were evaluated based on the following evaluation criteria, and the results are shown in Tables 5 to 7.

[0246] Contact angle evaluation criteria A: The contact angle of the outermost SiN layer of the Si substrate is less than 50° B: The contact angle of the outermost SiN layer of the Si substrate is 50° or more.

[0247] [Evaluation of film thickness after outgassing test] In step (5) of the above-mentioned [Method for evaluating outgassing], the film thickness of the portion of the SiN layer on the outermost layer of the Si substrate that was not in contact with the polyimide film was evaluated by X-ray reflectometry (XRR). The film thickness was measured by XRR for Example 3 and Comparative Example 6 using an X-ray reflectance measuring device (manufactured by Rigaku Corporation).

[0248] The results of film thickness measurement by XRR are shown below. Film thickness in Example 3: detection limit of 1.5 nm or less Film thickness in Comparative Example 6: 1.7 nm

[0249] <Pressure cooker test> The above photosensitive compositions (1) to (15) were used to evaluate the cured products by the following [Pressure Cooker Test].

[0250] [Pressure Cooker Test] Procedure (1): A photosensitive composition dissolved in methyl ethyl ketone to adjust the solid content to 75% by mass was applied onto a release polyethylene terephthalate (PET) film using an applicator, and the film was dried in an oven at 70°C for 10 minutes to form a photosensitive composition layer with a thickness of 20 μm. Step (2): Next, the release PET film was peeled off, and then the photosensitive composition layer was exposed using a ghi broadband exposure machine to obtain a cured film.

[0251] During the exposure, the exposure dose was such that a contact hole with a diameter of 50 μm could be formed. In the cases of Examples 1 to 3 and Comparative Examples 1 and 2, the i-line equivalent was 800 mJ / cm 2 , In the cases of Examples 4 to 6 and Comparative Examples 3 to 7, the i-line equivalent was 100 mJ / cm 2 , In the case of Comparative Example 8, the i-line equivalent was 2000 mJ / cm 2 , In the case of Example 7, the i-line equivalent is 1500 mJ / cm 2 , In the case of Comparative Example 9, the i-line equivalent was 400 mJ / cm 2 Each of the samples was exposed to 1000 kJ / cm².

[0252] Step (3): The cured film was then exposed to light and heated on a hot plate at 90° C. for 5 minutes, and then cured by heating in an oven at 200° C. for 1 hour, to obtain the desired cured product.

[0253] Step (4): Next, 4 g of the cured product and 40 g of pure water as an extraction solvent were placed in a polytetrafluoroethylene (PTFE) resin container with a lid, and the lid was closed.

[0254] Step (5): Next, the PTFE resin container with the lid closed was placed in a stainless steel autoclave and treated in an oven at 120° C. under 2 atmospheres for 20 hours.

[0255] Step (6): After cooling to room temperature of 23°C, the extract in the PTFE resin container with the lid closed was collected and the amount of fluoride ions eluted from the cured product was determined by ion chromatography. The amount of fluoride ion elution was quantified using an ICS5000 manufactured by Thermo Fisher Scientific. First, the peak heights of samples with three known fluoride ion concentrations were measured, and a calibration curve was created. Next, the peak heights of the extracts to be evaluated were measured, and then the amount of fluoride ion elution from the cured product was quantified using the calibration curve.

[0256] [Table 5]

[0257] From the results shown in Table 5, it can be seen that in Examples 1 to 3, where the C / Si was less than 0.2 and the detected amount of fluorine was 0.3 atm% or less, the contact angle in the outermost SiN layer of the Si substrate was less than 50°, and in Comparative Examples 1 and 2, where the detected amount of fluorine was 0.4 atm% or more, the contact angle in the outermost SiN layer of the Si substrate was 50° or more. The cationic polymerization initiator contained in the photosensitive composition differs between Examples 1 to 3 and Comparative Examples 1 and 2. It has been found that using a photosensitive composition containing a compound consisting of an anion moiety containing a borate anion and a cation moiety as the cationic polymerization initiator is advantageous from the viewpoint of suppressing outgassing.

[0258] [Table 6]

[0259] From the results shown in Table 6, it can be confirmed that in Examples 4 to 6, where C / Si was less than 0.2 and the detected amount of fluorine was 0.3 atm% or less, the contact angle in the outermost SiN layer of the Si substrate was less than 50°; in Comparative Examples 3 to 5, where C / Si was 0.2 or more, the contact angle in the outermost SiN layer of the Si substrate was 50° or more; and in Comparative Examples 6 and 7, where C / Si was 0.2 or more and the detected amount of fluorine was 0.4 atm% or more, the contact angle in the outermost SiN layer of the Si substrate was 50° or more.

[0260] The epoxy group-containing compound contained in the photosensitive composition is different between Example 4 and Comparative Example 4. It has been found that the use of a photosensitive composition containing an epoxy group-containing compound in which the content of the bifunctional epoxy monomer relative to the total mass of the tri- or higher functional epoxy group-containing compound and the bifunctional epoxy monomer is 2 mass% or less is advantageous from the viewpoint of suppressing outgassing.

[0261] In Examples 5 and 6, a photosensitive composition containing an epoxy group-containing compound (o-cresol novolac epoxy resin represented by chemical formula (A1-3)) with a bifunctional epoxy monomer content of 0 mass % was used. In Comparative Examples 3 to 5, a photosensitive composition containing an epoxy group-containing compound (bisphenol A novolac epoxy resin represented by chemical formula (A1-1-p1)) with a bifunctional epoxy monomer content of 17 mass % was used. In Comparative Examples 6 and 7, a photosensitive composition was used that contained an epoxy group-containing compound (bisphenol A novolac epoxy resin represented by chemical formula (A1-1-p1)) with a bifunctional epoxy monomer content of 17 mass %, and a compound consisting of an anion moiety and a cation moiety, including an antimony-based anion and a phosphorus-based anion, as a cationic polymerization initiator.

[0262] [Table 7]

[0263] From the results shown in Table 7, it can be confirmed that in Examples 3 and 7, where C / Si was less than 0.2 and the detected amount of fluorine was 0.3 atm% or less, the contact angle in the outermost SiN layer of the Si substrate was less than 50°, and in Comparative Examples 8 and 9, where C / Si was 0.2 or more, the contact angle in the outermost SiN layer of the Si substrate was 50° or more. Example 7 and Comparative Example 9 used the same photosensitive composition (7), but differed in the exposure dose in the above-mentioned procedure (1-3). It is recognized that the effect of suppressing outgassing is influenced by the content of the cationic polymerization initiator contained in the photosensitive composition and the exposure dose. [Explanation of symbols]

[0264] 10 boards, 20 interdigital electrodes, 30 SiN layers, 40 hot plates, 50 Si substrate, 60 photosensitive composition layer, 70 test boards, 80 Si substrate, 83 SiN layer, 90 Polyimide film, 100 Device Substrate 200 hardened body, 210 side wall, 220 Top plate, 300 hollow structure

Claims

1. a device substrate including a substrate, a comb-shaped electrode provided on the substrate, and a SiN layer formed on the substrate so as to cover the comb-shaped electrode; a sidewall formed on the device substrate so as to surround the comb-shaped electrode; a top plate portion formed on the side wall so as to face the device substrate; A hollow structure comprising: At least one of the side wall and the top plate portion is formed by curing a photosensitive composition, When the SiN layer is evaluated by X-ray photoelectron spectroscopy, the ratio of carbon to silicon (C / Si) is less than 0.2 and the amount of fluorine detected is 0.3 atomic % or less.

2. the photosensitive composition contains an epoxy group-containing compound and a cationic polymerization initiator; The hollow structure according to claim 1 , wherein the cationic polymerization initiator comprises a compound comprising an anion moiety containing a borate anion and a cation moiety.

3. the photosensitive composition contains an epoxy group-containing compound and a cationic polymerization initiator; The hollow structure according to claim 1, wherein the epoxy group-containing compound includes a trifunctional or higher functional epoxy group-containing compound, and the content of the bifunctional epoxy monomer is 2 mass% or less relative to the total mass of the trifunctional or higher functional epoxy group-containing compound and the bifunctional epoxy monomer.

4. A photosensitive composition for producing the hollow structure according to claim 1, comprising: the photosensitive composition is a material for at least one of the side wall and the top plate portion, A photosensitive composition, which, when evaluated on a SiN layer provided on a Si substrate by X-ray photoelectron spectroscopy using the [Method for evaluating outgassing] below, exhibits a carbon to silicon ratio (C / Si) of less than 0.2 and a detected amount of fluorine of 0.3 atm% or less. [Method for evaluating outgassing] Procedure (1-1): A photosensitive composition dissolved in methyl ethyl ketone to adjust the solid content to 75% by mass is applied onto a release polyethylene terephthalate (PET) film using an applicator, and the applied composition is dried in an oven at 70°C for 10 minutes to form a photosensitive composition layer having a thickness of 20 μm. Step (1-2): Next, the photosensitive composition layer is attached to the Si substrate so that the photosensitive composition layer and the Si substrate are in contact with each other, using a laminator under the conditions of 80°C, a pressure of 0.3 MPa, and a speed of 0.5 m / min. Step (1-3): Next, the release PET film is peeled off, and then the photosensitive composition layer is exposed using a ghi broadband exposure machine to obtain a test substrate. Step (2): Separately, on a Si substrate having a SiN layer as the outermost layer, a 50 μm thick polyimide film having a heat resistance of 300°C or higher, with the center cut out, is placed on the outer peripheral edge of the SiN layer on the Si substrate. Step (3): Next, the test substrate is placed on the polyimide film so that the photosensitive composition layer and the SiN layer face each other. Step (4): Next, the substrate is baked. The baking conditions are as follows: the substrate is heated on a hot plate at 90°C for 5 minutes, then heated to 200°C over 15 minutes, and held at 200°C for 1 hour. The substrate is then removed from the hot plate and allowed to cool. Step (5): After cooling, the test substrate and the polyimide film are removed, and then the portion of the SiN layer that faced the photosensitive composition layer but was not in contact with the polyimide film is evaluated by X-ray photoelectron spectroscopy. Step (6): Using an X-ray photoelectron spectrometer, the composition ratios of C / Si and F are calculated from the C1s spectrum for carbon (C), the Si2p spectrum for silicon (Si), and the F1s spectrum for fluorine (F).

5. the photosensitive composition contains an epoxy group-containing compound and a cationic polymerization initiator; the epoxy group-containing compound contains a tri- or higher functional epoxy group-containing compound, and the content of a bifunctional epoxy monomer is 2 mass% or less based on the total mass of the tri- or higher functional epoxy group-containing compound and the bifunctional epoxy monomer; 5. The photosensitive composition according to claim 4, wherein the cationic polymerization initiator comprises a compound comprising an anion moiety containing a borate anion and a cation moiety.

6. the photosensitive composition contains an epoxy group-containing compound and a cationic polymerization initiator; the epoxy group-containing compound includes a trisphenol-type polyglycidyl ether compound having three or more epoxy groups in one molecule, the cationic polymerization initiator comprises a compound having an anion moiety containing a borate anion and a cation moiety, the content of the cationic polymerization initiator is 1 part by mass or more and 5 parts by mass or less relative to 100 parts by mass of the epoxy group-containing compound, In the above procedure (1-3), the exposure dose was 10 mJ / cm ２ More than 2000mJ / cm ２ The photosensitive composition according to claim 5 , wherein the composition is exposed to light as follows:

7. the photosensitive composition contains an epoxy group-containing compound and a cationic polymerization initiator; the epoxy group-containing compound includes a novolac epoxy resin, the cationic polymerization initiator comprises a compound having an anion moiety containing a borate anion and a cation moiety, the content of the cationic polymerization initiator is 1 part by mass or more and 5 parts by mass or less relative to 100 parts by mass of the epoxy group-containing compound, In the above procedure (1-3), the exposure dose was 10 mJ / cm ２ More than 2000mJ / cm ２ The photosensitive composition according to claim 5 , wherein the composition is exposed to light as follows:

8. 5. The photosensitive composition according to claim 4, wherein the amount of fluorine ions eluted from the cured product is less than 1 ppm when the cured product is evaluated in the following [Pressure Cooker Test]. [Pressure cooker test] Procedure (1): A photosensitive composition dissolved in methyl ethyl ketone to adjust the solid content to 75% by mass is applied onto a release polyethylene terephthalate (PET) film using an applicator, and the applied composition is dried in an oven at 70°C for 10 minutes to form a photosensitive composition layer having a thickness of 20 μm. Step (2): Next, the release PET film is peeled off, and then the photosensitive composition layer is exposed using a ghi broadband exposure machine to obtain a cured film. Step (3): The cured film is then exposed to light and baked on a hot plate at 90°C for 5 minutes, and then cured by heating in an oven at 200°C for 1 hour to obtain the desired cured product. Step (4): Next, 4 g of the cured product and 40 g of pure water as an extraction solvent are placed in a polytetrafluoroethylene (PTFE) resin container with a lid, and the lid is closed. Step (5): Next, the PTFE resin container with the lid closed is placed in a stainless steel autoclave and treated in an oven at 120° C. under 2 atmospheres for 20 hours. Step (6): After cooling to room temperature of 23°C, the extract in the PTFE resin container with the lid closed is collected and the amount of fluoride ions eluted from the cured product is determined by ion chromatography.

9. a device substrate including a substrate, a comb-shaped electrode provided on the substrate, and a SiN layer formed on the substrate so as to cover the comb-shaped electrode; a sidewall formed on the device substrate so as to surround the comb-shaped electrode; a top plate portion formed on the side wall so as to face the device substrate; A method for producing a photosensitive composition for producing a hollow structure comprising: the photosensitive composition is a material for at least one of the side wall and the top plate portion, A method for producing a photosensitive composition, comprising: selecting a photosensitive composition that exhibits a carbon to silicon ratio (C / Si) of less than 0.2 and a detected amount of fluorine of 0.3 atomic % or less when a SiN layer provided on a Si substrate is evaluated by X-ray photoelectron spectroscopy in the following [Method for evaluating outgassing]. [Method for evaluating outgassing] Procedure (1-1'): A photosensitive composition is applied onto a release polyethylene terephthalate (PET) film using an applicator, and dried in an oven at 70°C for 10 minutes to form a photosensitive composition layer with a thickness of 20 μm. Step (1-2): Next, the photosensitive composition layer is attached to the Si substrate so that the photosensitive composition layer and the Si substrate are in contact with each other, using a laminator under the conditions of 80°C, a pressure of 0.3 MPa, and a speed of 0.5 m / min. Step (1-3): Next, the release PET film is peeled off, and then the photosensitive composition layer is exposed using a ghi broadband exposure machine to obtain a test substrate. Step (2): Separately, on a Si substrate having a SiN layer as the outermost layer, a 50 μm thick polyimide film having a heat resistance of 300°C or higher, with the center cut out, is placed on the outer peripheral edge of the SiN layer on the Si substrate. Step (3): Next, the test substrate is placed on the polyimide film so that the photosensitive composition layer and the SiN layer face each other. Step (4): Next, the substrate is baked. The baking conditions are as follows: the substrate is heated on a hot plate at 90°C for 5 minutes, then heated to 200°C over 15 minutes, and held at 200°C for 1 hour. The substrate is then removed from the hot plate and allowed to cool. Step (5): After cooling, the test substrate and the polyimide film are removed, and then the portion of the SiN layer that faced the photosensitive composition layer but was not in contact with the polyimide film is evaluated by X-ray photoelectron spectroscopy. Step (6): Using an X-ray photoelectron spectrometer, the composition ratios of C / Si and F are calculated from the C1s spectrum for carbon (C), the Si2p spectrum for silicon (Si), and the F1s spectrum for fluorine (F).

10. a device substrate including a substrate, a comb-shaped electrode provided on the substrate, and a SiN layer formed on the substrate so as to cover the comb-shaped electrode; a sidewall formed on the device substrate so as to surround the comb-shaped electrode; a top plate portion formed on the side wall so as to face the device substrate; A method for inspecting a photosensitive composition for producing a hollow structure comprising: the photosensitive composition is a material for at least one of the side wall and the top plate portion, The photosensitive composition inspection method, described below in [Method for evaluating outgassing], evaluates the carbon to silicon ratio (C / Si) and the amount of fluorine detected on a SiN layer provided on a Si substrate by X-ray photoelectron spectroscopy. [Method for evaluating outgassing] Procedure (1-1"): A photosensitive composition is applied onto a release polyethylene terephthalate (PET) film using an applicator, and dried in an oven at 70°C for 10 minutes to form a photosensitive composition layer with a thickness of 20 μm. Step (1-2): Next, the photosensitive composition layer is attached to the Si substrate so that the photosensitive composition layer and the Si substrate are in contact with each other, using a laminator under the conditions of 80°C, a pressure of 0.3 MPa, and a speed of 0.5 m / min. Step (1-3): Next, the release PET film is peeled off, and then the photosensitive composition layer is exposed using a ghi broadband exposure machine to obtain a test substrate. Step (2): Separately, on a Si substrate having a SiN layer as the outermost layer, a 50 μm thick polyimide film having a heat resistance of 300°C or higher, with the center cut out, is placed on the outer peripheral edge of the SiN layer on the Si substrate. Step (3): Next, the test substrate is placed on the polyimide film so that the photosensitive composition layer and the SiN layer face each other. Step (4): Next, the substrate is baked. The baking conditions are as follows: the substrate is heated on a hot plate at 90°C for 5 minutes, then heated to 200°C over 15 minutes, and held at 200°C for 1 hour. The substrate is then removed from the hot plate and allowed to cool. Step (5): After cooling, the test substrate and the polyimide film are removed, and then the portion of the SiN layer that faced the photosensitive composition layer but was not in contact with the polyimide film is evaluated by X-ray photoelectron spectroscopy. Step (6): Using an X-ray photoelectron spectrometer, the composition ratios of C / Si and F are calculated from the C1s spectrum for carbon (C), the Si2p spectrum for silicon (Si), and the F1s spectrum for fluorine (F).

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