JP5707779B2 - Photosensitive resin composition, photosensitive film, rib pattern forming method, hollow structure forming method, and electronic component - Google Patents

Description

  The present invention relates to a photosensitive resin composition that is excellent in moist heat resistance and has a high elastic modulus at high temperature and is capable of forming a thick film, a photosensitive film using the same, a rib pattern forming method, a hollow structure forming method, and an electronic component. .

  In recent years, as semiconductor devices have been highly integrated and miniaturized, rapid increase in capacity and cost have been realized. A package of an element that exhibits a specific electrical function by forming an electrode pattern or a fine structure on the surface of a single crystal wafer, represented by a surface acoustic wave (SAW) filter, has characteristics when the functional part surface is covered with a resin or the like. In order to change, a hollow structure is required so that other objects do not touch particularly functionally important parts of the device surface. In addition, image sensors represented by CMOS and CCD sensors have a hollow structure in which the light receiving unit is covered with a glass lid in order to protect the element from moisture and dust that hinder imaging and not to block light from the outside. It has become. In addition, a hollow structure is used to protect movable parts in MEMS (Micro Electro Mechanical Systems) for high frequency applications such as gyro sensors and millimeter wave radars.

  These elements that require a hollow structure conventionally form a hollow structure by processing and joining inorganic materials (see Patent Document 1 below). However, the processing of these inorganic materials is problematic in that the cost is increased due to an increase in the number of parts and the number of processes, and it is difficult to reduce the size and height due to structural limitations (Patent Document 2 below). 3).

  In order to solve this problem, a hollow structure forming method using a non-photosensitive resin film has been proposed as an alternative to inorganic materials (ceramics) (see Patent Document 4 below). However, even with this method, there are problems with reliability such as heat and humidity resistance and retention of hollow parts, and the need for drilling electrode parts with a laser for miniaturization is a problem, which is satisfactory in terms of quality and cost. It is not something that can be done.

  Therefore, a method of forming a hollow structure using a photosensitive resin material has been reported in order to enable easy drilling by photolithography and to have moisture and heat resistance and hollow portion retention (Patent Documents 5 and 6 below). 7, 8 and 9).

JP-A-8-191181 JP 2001-244785 A JP-A-8-204482 JP-A-6-164292 JP 2008-227748 A JP 2004-64732 A JP 2008-963 A JP 2008-964 A JP 2008-250200 A

  However, the acoustic wave device described in Patent Document 5 forms a photosensitive resin (epoxy resin) with a thickness of about 10 μm as a part of a rib member having a hollow structure. A method of forming a thick rib material by one exposure is not disclosed. The surface acoustic wave device described in Patent Document 6 uses a photosensitive resin as a sealing resin inflow prevention weir, and the fine pattern forming property and reliability of the photosensitive resin are completely considered. Not.

  In Patent Documents 7, 8 and 9, a photosensitive epoxy resin is mentioned as a photosensitive resin capable of forming a thick film having a thickness of about 30 μm necessary for forming a rib having a hollow structure, and is excellent in pattern formability. However, the reliability as a MEMS device is unknown.

  In general, a photosensitive resin has a limited material selection range as compared with a thermosetting resin only by heating. Therefore, the composition of the thermosetting resin is excellent in heat and humidity resistance and adhesion to a substrate. It is well known that it is more difficult than the case. For example, the photosensitive epoxy resins described in Patent Documents 5 to 9 tend to have higher moisture absorption rate and moisture permeability than thermosetting epoxy resins, and sufficient moisture and heat resistance cannot be obtained, which is desirable as a hollow structure device. There is a problem that the reliability of the system cannot be ensured. In addition, in Patent Documents 5 to 9, there is no specific description of the elastic modulus at high temperature after photocuring for the photosensitive epoxy resin, and deformation, sagging, or dent of the resin during manufacture or use is not possible. It may occur that the hollow structure retainability is impaired, resulting in characteristic damage. In particular, when a hollow structure device is molded with a sealing resin in a later process in order to ensure reliability and modularize with other devices, it is hollow when pressure is applied to the hollow structure under high temperature and high pressure conditions. Since there is a high risk of crushing, the shape and electrical characteristics cannot be maintained, which is a serious problem. Further, in the high-temperature repetitive process at the time of solder reflow performed when mounting on a substrate, there is a manufacturing problem that not only the deformation but also the possibility of occurrence of cracks and peeling occurs. In addition, the acoustic wave devices described in Patent Documents 5 to 9 are to form a pattern with an opening diameter of 100 μm or more by photolithography, and are not disclosed for forming a fine pattern smaller than that, It is unclear whether a slight difference pattern can be formed by the photosensitive epoxy resin.

  On the other hand, examples of the photosensitive resin having high heat resistance and high reliability include photosensitive polyimide resins in addition to photosensitive epoxy resins. Generally, a photosensitive polyimide resin forms a film having a thickness of 10 μm or more. There is a problem that it is difficult. Therefore, it is difficult to form a sufficient thickness required for forming a hollow rib. Rib formation with a thick film and a fine pattern is indispensable for miniaturization and high precision of hollow structure devices, but the selection range of materials that can be applied to photosensitive polyimide resin is small, and this requirement can be fully met. I can't. In addition, when the photosensitive polyimide resin is applied to the formation of a lid having a hollow structure, since the lid is a thin film, it cannot withstand the pressure under high temperature and high pressure conditions. Although it can be used together with a material having high rigidity as a reinforcing material, another problem arises that the material cost and the number of production steps increase. As described above, the conventional photosensitive polyimide resin is required to have a narrow range of application in order to form a hollow rib portion and a lid portion, and to greatly improve the structure, physical properties and characteristics of the material itself.

  Therefore, the present invention has been made to solve the above-described problems, and is excellent in fine pattern formation, the cured product has a high elastic modulus at high temperature, excellent in heat and moisture resistance, and has a hollow structure. It aims at providing the photosensitive resin composition which is excellent also in the property, and the photosensitive film using the same.

In order to achieve the above object, the present inventors have improved the reliability, high elastic modulus, thick film formability and composition of the photosensitive resin composition applied to the lid member or rib member for forming the hollow structure. result of a comprehensive intensive study the pattern formability, by the optimizes the constituents of the photosensitive resin composition, a combination of photopolymerizable compound and the thermally crosslinkable compound in a specific ratio, achieving the above object The present inventors have found that this can be done and have completed the present invention.

That is, the present invention relates to the following (1) to (13).
(1) A photosensitive resin composition used as a rib member or a lid member for forming a hollow structure in an electronic component having a hollow structure, wherein (A) a thermally crosslinkable compound and (B) at least one ethylenic non-polymerizing composition. A photopolymerizable compound having a saturated group and (C) a photopolymerization initiator, and the content of the (A) thermally crosslinkable compound is the above (A) condensation-reactive thermally crosslinkable compound and the above ( B) The photosensitive resin composition which is 10-40 mass parts when the total amount of the photopolymerizable compound which has an at least 1 ethylenically unsaturated group is 100 mass parts.
(2) The photosensitive resin composition according to (1), wherein the (A) heat-crosslinkable compound is a condensation-reactive heat-crosslinkable compound.
(3) The photosensitive resin composition according to (2), wherein the (A) condensation-reactive thermally crosslinkable compound is a compound having at least one methylol group or alkoxyalkyl group.
(4) The photosensitive resin composition according to (2), wherein the (A) thermally crosslinkable compound is a melamine resin or urea resin substituted at the N-position with a methylol group and / or an alkoxymethyl group.
(5) The photosensitivity according to any one of (1) to (4), wherein (B) the photopolymerizable compound having at least one ethylenically unsaturated group is an acrylate compound or a methacrylate compound containing an amide group. Resin composition.
(6) The photosensitive resin composition includes (A) a thermally crosslinkable compound, (B) a photopolymerizable compound having at least one ethylenically unsaturated group, (C) a photopolymerization initiator, and (D) (1) The photosensitive resin composition according to any one of (1) to (5), further comprising an inorganic filler having an average aspect ratio of 30 to 100 and a volume average particle diameter of 5 to 50 μm. object.
(7) The photosensitive resin composition according to any one of (1) to (6), wherein a tensile elastic modulus after curing is 1.2 GPa or more at 180 ° C.
(8) A photosensitive resin composition according to any one of (1) to (7), which is a photosensitive film used as a lid member or a rib member for forming the hollow structure in an electronic component having a hollow structure. A photosensitive film formed by molding a product into a film.
(9) A photosensitive resin layer laminating step of laminating the photosensitive resin composition according to any one of (1) to (7) or the photosensitive film of (8) on a substrate, and the photosensitive property. An exposure step of irradiating a predetermined portion of the resin layer with an actinic ray through a mask to photo-cure the exposed portion; a removing step of removing a portion other than the exposed portion of the photosensitive resin layer using a developer; and the photosensitive layer The rib pattern formation method for forming a hollow structure which has the thermosetting process of thermosetting the said exposure part of a conductive resin layer, and forming resin cured | curing material.
(10) The photosensitive resin composition according to any one of (1) to (7) or so as to form a lid portion having a hollow structure on a rib pattern provided to form a hollow structure on the substrate. (8) A photosensitive resin layer laminating step for laminating the photosensitive film, an exposure step of irradiating a predetermined portion of the photosensitive resin layer with an actinic ray to photocure an exposed portion, and, if necessary, the photosensitivity. A hollow having a removal step of removing a portion other than the exposed portion of the photosensitive resin layer using a developer, and a thermosetting step of thermosetting the exposed portion of the photosensitive resin layer to form a cured resin. Structure formation method.
(11) The method for forming a hollow structure according to (10), wherein the rib pattern provided for forming the hollow structure on the substrate is formed by the method according to claim (9).
(12) A hollow structure in which a rib portion or a lid portion of a hollow structure is formed using the photosensitive resin composition according to any one of (1) to (7) or the photosensitive film according to (8). Electronic components.
(13) The electronic component according to (12), which is a surface acoustic wave filter.

  The photosensitive resin composition of the present invention contains a thermally crosslinkable compound in a composition having a photopolymerizable compound having at least one ethylenically unsaturated group and a photopolymerization initiator, and includes the heat crosslinkable compound. By optimizing the amount, it is possible to achieve both fine pattern formability, high elastic modulus at high temperature, and high adhesion to the substrate. Therefore, the resin cured product of the photosensitive resin composition of the present invention has a high elastic modulus at a high temperature and is excellent in wet heat resistance and rigidity, and thus has excellent hollow structure retention. Further, by using a compound having a specific reaction form and structure as the above-mentioned heat crosslinkable compound, for example, it is possible to obtain a hollow part retainability that can withstand a sealing resin mold pressure at a high temperature of 150 to 180 ° C. In addition, the hollow structure retainability can be further improved. The photosensitive resin composition of the present invention can be obtained by using an acrylate compound or a methacrylate compound as a photopolymerizable compound having (B) at least one ethylenically unsaturated group, together with the specific heat-crosslinkable compound. Even in the case of a film, a cured resin product having excellent photocurability and excellent rigidity can be obtained. In particular, an acrylate compound or a methacrylate compound containing an amide group can maintain high adhesion to a substrate and has a great effect on improving reflow crack resistance. As described above, the photosensitive resin composition of the present invention has a better heat and moisture resistance obtained by a combination of a specific thermal crosslinking material and a specific photopolymerizable compound, for example, as in a PCT (pressure cooker) test. High adhesiveness can be maintained even in harsh, high temperature and high humidity atmospheres, and the reliability of hollow structure devices can be secured.

  In addition, according to the present invention, it has excellent resistance to moisture and heat, has a high high-temperature elastic modulus, has resistance to temperature and pressure at the time of molding of the sealing material, and is compatible with solvent development, and can be used in a film form. A photosensitive resin composition capable of forming images well, a photosensitive film using the same, a rib pattern and hollow structure forming method, and an electronic component can be provided.

  Furthermore, the photosensitive resin composition of the present invention can easily produce a cured resin having high elasticity at high temperature and excellent rigidity by containing an inorganic filler having a specific aspect ratio and volume average particle diameter. It is possible to achieve high hollow retention even under pressure under high temperature and high pressure conditions.

It is a figure which shows suitable one Embodiment of the SAW filter which is one of the electronic components of this invention, and its manufacturing method. It is a figure which shows the SAW filter with which the metal ball which is another embodiment of this invention is mounted. It is a figure which shows another suitable embodiment of the SAW filter which is one of the electronic components of this invention, and its manufacturing method. It is a figure which shows the SAW filter sealed with the sealing material which is another embodiment of this invention. It is a figure which shows the manufacturing method of the SAW filter sealed with the sealing material which is another embodiment of this invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings as the case may be.
In the following description, the same or corresponding parts are denoted by the same reference numerals, and redundant description is omitted. Further, the dimensional ratios in the drawings are not limited to the illustrated ratios.

  In the present invention, since the rib portion and the lid portion of the hollow structure are patterned by light exposure, the thick film is excellent in light transmittance and fine pattern property, and in order to improve heat and moisture resistance, It is necessary to be a photosensitive resin having high heat resistance and low hygroscopicity and low moisture permeability. As described above, the use of a photosensitive epoxy resin or a photosensitive polyimide resin does not necessarily meet this purpose. On the other hand, a photopolymerizable compound having at least one ethylenically unsaturated group has high photopolymerization reactivity and not only excellent photosensitivity characteristics such as thick film formation and pattern formation, but also heat resistance of the cured resin. It is a resin that is particularly suitable in the present invention because it is easy to introduce a chemical structure that improves the glass transition temperature and, more specifically, lowers the moisture absorption rate into the molecule. Further, since the photopolymerizable compound having at least one ethylenically unsaturated group has a wide selection range as a low-viscosity material, the photosensitive resin composition applied on the substrate when forming the rib portion or the lid portion is used. It is easy to arbitrarily adjust the viscosity. Although it is possible to reduce the viscosity of the photosensitive resin composition to be applied by using a solvent, when using a photopolymerizable compound having at least one ethylenically unsaturated group, characteristics of the resin composition after curing and The amount of solvent that adversely affects reliability can be reduced. In addition, even when the photosensitive resin composition contains a blending amount of an inorganic filler, for example, even if the blending amount increases to 50% by weight, the coating property and film formability of the photosensitive resin composition are maintained. it can.

  However, the cured product of only a photopolymerizable compound having at least one ethylenically unsaturated group cannot sufficiently increase the high-temperature elastic modulus. In order to achieve this object, the photosensitive resin composition of the present invention is characterized in that a thermally crosslinkable compound is used in combination with the photopolymerizable compound. Below, the photosensitive resin composition of this invention is demonstrated.

(Photosensitive resin composition)
As the thermally crosslinkable compound of the component (A) contained in the photosensitive resin composition of the present invention, an epoxy resin, a polyisocyanate compound, a blocked polyisocyanate compound, an amino derivative, the α-position is a methylol group, an alkoxymethyl group. Examples include substituted phenol resins, melamine resins substituted at the N-position with methylol groups and / or alkoxymethyl groups, urea resins, and the like. Among these, a condensation-reactive thermally crosslinkable compound that is a phenol resin substituted at the α-position with a methylol group or an alkoxymethyl group, a melamine resin substituted with a methylol group and / or an alkoxymethyl group at the N-position, or a urea resin Is preferred in the present invention. Epoxy compounds, polyisocyanate compounds, blocked polyisocyanate compounds, or amino derivatives have the effects of the present invention, but the moisture absorption rate and moisture permeability tend to be slightly higher, and the glass transition temperature and adhesive strength are high. Improvement effect is small. For this reason, heat-crosslinkable compounds based on these compounds need to be thoroughly examined before use when applied as a material for ribs or lids of hollow structure devices that require strict reliability such as leaving PCT for a long time. It is. On the other hand, a phenol resin in which the α-position which is a condensation-reactive heat-crosslinkable compound is substituted with a methylol group or an alkoxymethyl group, or a melamine resin in which the N-position is substituted with a methylol group and / or an alkoxymethyl group, urea The resin has a different curing reaction mechanism from the photopolymerizable compound having at least one ethylenically unsaturated group. Therefore, the resin is less likely to react with each other, and the photopolymerizable compound is formed as a highly crosslinked particle by a condensation reaction. It takes the form of being uniformly dispersed in the compound. This dispersion form produces not only an increase in the elastic modulus at high temperatures, but also an effect of suppressing an increase in moisture absorption rate and moisture permeability and a decrease in adhesive force. That is, the condensation-reactive thermally crosslinkable compound is an effective component for increasing the heat resistance and the elastic modulus of the photosensitive resin composition, while being uniformly dispersed in the photosensitive resin composition. Thus, it is considered that an increase in moisture absorption rate and moisture permeability and a decrease in adhesiveness can be suppressed by a cured product of a photopolymerizable compound having one ethylenically unsaturated group surrounding the thermally crosslinkable compound.

  The thermally crosslinkable compound of the present invention further has one or more methylol groups and alkoxymethyl groups in the molecule, and these groups are bonded to the benzene ring, or the N-position is a methylol group and / or Examples include melamine resins substituted with alkoxymethyl groups, urea resins, and the like. Among these, from the viewpoints of solubility, varnish stability, sensitivity, and high-temperature elastic modulus of the cured film, melamine in which the N-position is substituted with a methylol group and / or alkoxymethyl group as shown in the general formula (1) Resins, urea resins and the like are preferred. These are used alone or in combination of two or more.

[式中、Ｒ^１は同一でも異なってもよく、メチロール基、炭素数１〜４のアルコキシ基を含むアルコキシメチル基又は水素原子であるが、少なくとも１つはメチロール基又は上記のアルコキシメチル基である。]

[Wherein, R ¹ may be the same or different and is a methylol group, an alkoxymethyl group containing a C 1-4 alkoxy group or a hydrogen atom, but at least one is a methylol group or the above-mentioned alkoxymethyl group. is there. ]

As a compound shown by said General formula (1), the compound of the following structures is mentioned, for example, These are commercially available.

  Since the compound having the structure represented by the above general formulas (2) to (6) does not contain a methylol group, there is little generation of free components such as formaldehyde at the time of thermosetting, and the reliability of the hollow structure device is greatly improved. Can be improved. Although there is no restriction | limiting in particular in these compounds which can be used for this invention, The compound shown by General formula (2) is especially preferable from the point of stability at the high temperature of a cured film.

  The content of the (A) thermally crosslinkable compound is 100 masses of the total amount of the (A) condensation-reactive thermally crosslinkable compound and the (B) photopolymerizable compound having at least one ethylenically unsaturated group. Parts, it is 10 to 40 parts by mass, more preferably 15 to 35 parts by mass. In the present invention, when the content of the heat-crosslinkable compound (A) is less than 10 parts by mass, the content of the crosslinking component in the photosensitive resin composition is reduced, so that the heat resistance is increased and the high elasticity at high temperature. The effect of increasing the efficiency cannot be obtained, the hollow structure of the device cannot be maintained, and the electrical characteristics of the device itself greatly fluctuate. On the other hand, when the amount exceeds 40 parts by mass, the content of the photocurable component (B) decreases, so that pattern formation by light irradiation becomes difficult.

  The photosensitive resin composition of the present invention contains (B) a photopolymerizable compound having at least one ethylenically unsaturated group and (C) a photopolymerization initiator, in addition to the above-mentioned thermally crosslinkable compound.

  Examples of the polymerizable compound having at least one ethylenically unsaturated group include a compound obtained by reacting an α, β-unsaturated carboxylic acid with a polyhydric alcohol, an amide bond, and at least one ethylenically unsaturated group. Urethanes such as a polymerizable compound having a saturated group, a bisphenol A-based (meth) acrylate compound, a compound obtained by reacting a glycidyl group-containing compound with an α, β-unsaturated carboxylic acid, and a (meth) acrylate compound having a urethane bond Monomers or urethane oligomers, (meth) acrylic acid alkyl esters and the like can be mentioned. These are used alone or in combination of two or more.

  Examples of the compound obtained by reacting the polyhydric alcohol with an α, β-unsaturated carboxylic acid include, for example, polyethylene glycol di (meth) acrylate having 2 to 14 ethylene groups and 2 to 2 propylene groups. 14 polypropylene glycol di (meth) acrylate, polyethylene polypropylene glycol di (meth) acrylate having 2 to 14 ethylene groups and 2 to 14 propylene groups, trimethylolpropane di (meth) acrylate, Trimethylolpropane tri (meth) acrylate, ethylene oxide (EO) modified trimethylolpropane tri (meth) acrylate, propylene oxide (PO) modified trimethylolpropane tri (meth) acrylate, EO, PO modified trimethylolpropane tri (meth) acrylate Examples include relate, tetramethylolmethane tri (meth) acrylate, tetramethylolmethanetetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, and the like. These are used alone or in combination of two or more.

［式（７）中、Ｒ^３１、Ｒ^３２及びＲ^３３は各々独立に、２価の有機基を示し、Ｒ^３４は水素原子又はメチル基を示し、Ｒ^３５及びＲ^３６は各々独立に、水素原子、炭素数１〜４のアルキル基又はフェニル基を示す。］ As the polymerizable compound having the amide bond and two or more ethylenically unsaturated groups, a compound represented by the following general formula (1) is preferable.

[In the formula (7), R ³¹ , R ³² and R ³³ each independently represents a divalent organic group, R ³⁴ represents a hydrogen atom or a methyl group, and R ³⁵ and R ³⁶ each independently represent hydrogen. An atom, an alkyl group having 1 to 4 carbon atoms or a phenyl group is shown. ]

  The polymerizable compound represented by the general formula (1) is a di (meth) acrylate having an amide bond, obtained by reacting an oxazoline group-containing compound with a carboxyl group-containing compound and / or a phenolic hydroxyl group-containing compound. Preferably there is. The polymerizable compound represented by the general formula (7) includes, for example, a bisoxazoline represented by the following general formula (8), a compound having two phenolic hydroxyl groups in one molecule, and (meth) acrylic. It can be obtained by reacting with an acid.

一般式（８）中、Ｙ^４は２価の有機基を示すが、置換基を有していてもよいフェニレン基、置換基を有していてもよいピリジレン基、又は炭素数１〜１０の枝分かれしていてもよいアルキレン基であることが好ましい。また、Ｒ^４５及びＲ^４６は各々独立に、水素原子、炭素数１〜４のアルキル基又はフェニル基を示す。

In General Formula (8), Y ⁴ represents a divalent organic group, but a phenylene group which may have a substituent, a pyridylene group which may have a substituent, or a carbon number of 1 to 10 An alkylene group which may be branched is preferred. R ⁴⁵ and R ⁴⁶ each independently represent a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or a phenyl group.

  Examples of the bisoxazoline represented by the general formula (8) include 2,2 ′-(1,3-phenylene) bis-2-oxazoline and 2,6-bis (4-isopropyl-2-oxazoline-2). -Yl) pyridine, 2-2'-isopropylidenebis (4-phenyl-2-oxazoline), 2-2'-isopropylidenebis (4-tertiarybutyl-2-oxazoline) and the like. These can be used alone or in combination of two or more.

  Examples of the compound having two phenolic hydroxyl groups in one molecule include biphenol, tetramethylbiphenol, dihydroxynaphthalene, dihydroxymethylnaphthalene, dihydroxydimethylnaphthalene, bis (4-hydroxyphenyl) ketone, bis (4-hydroxy-3, 5-dimethylphenyl) ketone, bis (4-hydroxy-3,5-dichlorophenyl) ketone, bis (4-hydroxyphenyl) sulfone, bis (4-hydroxy-3,5-dimethylphenyl) sulfone, bis (4-hydroxy) -3,5-dichlorophenyl) sulfone, bis (4-hydroxyphenyl) hexafluoropropane, bis (4-hydroxy-3,5-dimethylphenyl) hexafluoropropane, bis (4-hydroxy-3,5-dichlorophenyl) Xafluoropropane, bis (4-hydroxyphenyl) dimethylsilane, bis (4-hydroxy-3,5-dimethylphenyl) dimethylsilane, bis (4-hydroxy-3,5-dichlorophenyl) dimethylsilane, bis (4-hydroxy) Phenyl) methane, bis (4-hydroxy-3,5-dichlorophenyl) methane, bis (4-hydroxy-3,5-dibromophenyl) methane, 2,2-bis (4-hydroxyphenyl) propane, 2,2- Bis (4-hydroxy-3,5-dimethylphenyl) propane, 2,2-bis (4-hydroxy-3,5-dichlorophenyl) propane, 2,2-bis (4-hydroxy-3-methylphenyl) propane, 2,2-bis (4-hydroxy-3-chlorophenyl) propane, bis (4-hydroxy) Phenyl) ether, bis (4-hydroxy-3,5-dimethylphenyl) ether, bis (4-hydroxy-3,5-dichlorophenyl) ether, 9,9-bis (4-hydroxyphenyl) fluorene, 9,9- Bis (4-hydroxy-3-methylphenyl) fluorene, 9,9-bis (4-hydroxy-3-chlorophenyl) fluorene, 9,9-bis (4-hydroxy-3-bromophenyl) fluorene, 9,9- Bis (4-hydroxy-3-fluorophenyl) fluorene, 9,9-bis (4-hydroxy-3-methoxyphenyl) fluorene, 9,9-bis (4-hydroxy-3,5-dimethylphenyl) fluorene, 9 , 9-bis (4-hydroxy-3,5-dichlorophenyl) fluorene, 9,9-bis (4-hydroxy-) 3,5-dibromophenyl) fluorene and the like. Among these, 2,2-bis (4-hydroxy-3,5-dichlorophenyl) propane is particularly preferable. These can be used alone or in combination of two or more.

  The above-mentioned polymerizable compound having an amide bond and at least one ethylenically unsaturated group in the molecule can be used alone or in combination of two or more.

  The reaction between the phenolic hydroxyl group-containing compound and / or the carboxyl group-containing compound and the oxazoline group-containing compound is preferably performed at a reaction temperature of 50 to 200 ° C. When the reaction temperature is less than 50 ° C., the reaction is slow, and when the reaction temperature is 200 ° C. or more, side reactions tend to occur. In some cases, the reaction may be carried out in a polar organic solvent such as dimethylformamide, dimethylacetamide, or dimethylsulfoxide.

［式中、ｍとｎとの比は、１００／０〜０／１００である。］ Examples of the compound obtained by reacting the glycidyl group-containing compound with an α, β-unsaturated carboxylic acid include epoxy resins such as novolak type epoxy resins, bisphenol type epoxy resins, salicylaldehyde type epoxy resins, and (meth) Examples thereof include an epoxy acrylate compound obtained by reacting acrylic acid. An acid-modified epoxy acrylate compound obtained by reacting an acid anhydride such as tetrahydrophthalic anhydride with the OH group of the epoxy acrylate compound can also be used. As such an acid-modified epoxy acrylate compound, for example, EA-6340 (trade name, manufactured by Shin-Nakamura Chemical Co., Ltd.) represented by the following general formula (9) is commercially available.

[Wherein, the ratio of m to n is 100/0 to 0/100. ]

  Examples of the (meth) acrylate compound having a urethane bond include (meth) acrylic monomers having an OH group at the β-position, such as 2-hydroxyethyl acrylate, dipentaerythritol pentaacrylate, and pentaerythritol triacrylate, isophorone diisocyanate, 2, Addition reaction products with diisocyanate compounds such as 6-toluene diisocyanate, 2,4-toluene diisocyanate, 1,6-hexamethylene diisocyanate; EO-modified urethane di (meth) acrylate; EO or PO-modified urethane di (meth) acrylate; Urethane (meth) acrylate; diol compound, bifunctional epoxy acrylate having two hydroxyl groups and two at least one ethylenically unsaturated group in the molecule, and polyisocyanate Applied Physics, and the like.

  The photopolymerizable compound having at least one ethylenically unsaturated group described above is used alone or in combination of two or more.

  Among these photopolymerizable compounds, a photopolymerizable compound having an amide bond and two or more ethylenically unsaturated groups is preferable from the viewpoints of heat resistance of the cured film, elasticity, and adhesion to the substrate.

  The content of the photopolymerizable compound (B) having at least one ethylenically unsaturated group includes the (A) condensation-reactive thermally crosslinkable compound and the (B) at least one ethylenically unsaturated group. When the total amount of the photopolymerizable compound is 100 parts by mass, it is 60 to 90 parts by mass, more preferably 65 to 85 parts by mass. (B) When the content of the photopolymerizable compound having at least one ethylenically unsaturated group is 60 to 90 parts by mass, the formed rib pattern and lid shape are good, and sufficient resin strength is obtained. The hollow structure is not easily crushed.

  The photopolymerization initiator as the component (C) contained together with the photopolymerizable compound having at least one ethylenically unsaturated group (B) is not particularly limited as long as it generates free radicals by actinic rays. For example, aromatic ketones, acyl phosphine oxides, oxime esters, quinones, benzoin ether compounds, benzyl derivatives, 2,4,5-triarylimidazole dimers, acridine derivatives, N-phenylglycine, N-phenyl Examples thereof include glycine derivatives and coumarin compounds.

  Examples of the aromatic ketone include benzophenone, N, N′-tetramethyl-4,4′-diaminobenzophenone (that is, Michler ketone), N, N′-tetraethyl-4,4′-diaminobenzophenone, 4-methoxy-4. '-Dimethylaminobenzophenone, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butan-1-one, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholino- Propan-1-one is mentioned.

  Examples of the acylphosphine oxide include bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide and 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide.

  Examples of oxime esters include 1,2-octanedione-1- [4- (phenylthio) -2- (O-benzoyloxime)].

  Examples of quinones include 2-ethylanthraquinone, phenanthrenequinone, 2-tert-butylanthraquinone, octamethylanthraquinone, 1,2-benzanthraquinone, 2,3-benzanthraquinone, 2-phenylanthraquinone, 2,3-diphenyl. Examples include anthraquinone, 1-chloroanthraquinone, 2-methylanthraquinone, 1,4-naphthoquinone, 9,10-phenanthraquinone, 2-methyl-1,4-naphthoquinone, and 2,3-dimethylanthraquinone.

  Examples of the benzoin ether compound include benzoin methyl ether, benzoin ethyl ether, and benzoin phenyl ether.

  Examples of the benzyl derivative include benzoin compounds such as benzoin, methylbenzoin, and ethylbenzoin, and benzyldimethyl ketal.

  Examples of the 2,4,5-triarylimidazole dimer include 2- (2-chlorophenyl) -1- [2- (2-chlorophenyl) -4,5-diphenyl-1,3-diazol-2- Yl] -4,5-diphenylimidazole, 2- (o-chlorophenyl) -4,5-diphenylimidazole dimer, 2- (o-chlorophenyl) -4,5-di (methoxyphenyl) imidazole dimer 2- (o-fluorophenyl) -4,5-diphenylimidazole dimer, 2- (o-methoxyphenyl) -4,5-diphenylimidazole dimer, 2- (p-methoxyphenyl) -4, 5-diphenylimidazole dimer is mentioned.

  Examples of the acridine derivative include 9-phenylacridine and 1,7-bis (9,9'-acridinyl) heptane.

  (C) A photoinitiator may be synthesize | combined by a conventional method and a commercially available thing may be obtained. Available (C) photopolymerization initiators include, for example, Irgacure-369, Irgacure-907, Irgacure-651, Irgacure-819 (all of which are manufactured by Ciba Specialty Chemicals, Inc., trade name), oxime Examples thereof include compounds having an ester bond.

Among the above-described (C) photopolymerization initiators, compounds having an oxime ester bond are particularly preferable from the viewpoint of improving photocurability and increasing sensitivity. More specifically, as a compound having an oxime ester bond, 1,2-octanedione-1- [4- (phenylthio) phenyl] -2- (O-benzoyloxime) represented by the following formula (10) (trade name) : OXE-01, manufactured by Ciba Specialty Chemicals), 1- [9-ethyl-6- (2-methylbenzoyl) -9H-carbazol-3-yl] ethanone 1- (O-acetyloxime) (trade name: OXE-02, manufactured by Ciba Specialty Chemicals), 1-phenyl-1,2-propanedione-2- [O- (ethoxycarbonyl) oxime] (trade name: Quantacure-PDO, manufactured by Nippon Kayaku Co., Ltd.), etc. Can be mentioned.

  The said (C) photoinitiator can be used individually by 1 type or in combination of 2 or more types.

  The content of the (C) photopolymerization initiator is preferably 0.1 to 20% by mass, and preferably 0.3 to 10% by mass based on the total solid content of the photosensitive resin composition. More preferably, it is particularly preferably 0.5 to 5% by mass. (C) By making content of a photoinitiator into 0.1-20 mass%, the sensitivity of the photosensitive resin composition can be improved and the deterioration of a resist shape can be prevented.

  The photosensitive resin composition of the present invention comprises (A) a thermally crosslinkable compound, (B) a photopolymerizable compound having at least one ethylenically unsaturated group, and (C) a photopolymerization initiator. An inorganic filler having an aspect ratio of 30 to 100 and a volume average particle diameter of 5 to 50 μm can be contained.

  In the photosensitive resin composition of the present invention, by using an inorganic filler having such an aspect ratio and volume average particle diameter, the cured resin product exhibits low hygroscopicity, moisture permeability, and excellent rigidity. For example, it is possible to obtain a hollow portion retainability that can withstand a sealing resin mold pressure at a high temperature. Further, when an inorganic filler is contained in the photosensitive resin composition, the thick film formability and fine pattern formability, which are essential photosensitive characteristics of the present invention, tend to decrease, but the above aspect ratio and volume average particle By using an inorganic filler having a diameter, it is possible to suppress such a decrease.

  In the present invention, the aspect ratio is defined as a ratio of the thickness to the major axis of the inorganic filler (major axis / thickness), and does not mean (major axis / minor axis) in the plane of the inorganic filler. As the shape of the inorganic filler, a shape generally called a plate shape (including a flat plate shape, a disk shape, a flat shape and a scale shape) is preferable, and in the present invention, a scale shape is more preferable. The aspect ratio of the inorganic filler is calculated using a scanning electron microscope or a transmission electron microscope, but in the present invention, the volume average particle diameter of the inorganic filler is 5 μm or more, and can be obtained by a scanning electron microscope. . That is, here, the average aspect ratio is measured by observation with a scanning electron microscope (SEM). First, an inorganic filler is fixed to the SEM sample stage, the observation magnification is increased to the maximum to allow one particle to enter the field of view, the shape is observed, and the surface having the largest observation area of the particle (that is, relatively smooth and spreads). The image is captured (captured) from the direction of the chamfered surface, for example, the cleaved surface (X plane) in mica or the like. Next, by rotating the sample stage, unlike the previous case, the surface with the smallest observation area of the particles (that is, the surface to be observed as the thickness of the plate if the particles are plate-like, such as a laminated cross section (for example, mica) Capture (shoot) an image from the direction of the fracture surface); From the image (photograph) thus obtained, first, for the particle image of the X surface, the smallest circle inscribed in this is set and the diameter is measured to define the “major axis” of the particle, In the Y-plane particle image, the distance between the parallel lines drawn so that the two parallel lines are closest to each other and sandwich the particles is defined as “thickness”, and the major axis is divided by the thickness to obtain individual particles. Find the aspect ratio. This operation is performed on 100 arbitrarily extracted inorganic fillers, and an average value is calculated to obtain an average aspect ratio. In the present invention, when the average aspect ratio is less than 30, light scattering in the photosensitive resin composition is reduced, so that the photosensitive characteristics are improved, but the moisture absorption and moisture permeability reduction effects to the photosensitive resin are not so much. In addition, the effect of increasing the elastic modulus is also reduced, and for example, it is not possible to obtain a hollow part retaining property that can withstand the sealing resin mold pressure at a high temperature. On the other hand, when the average aspect ratio exceeds 100, the photosensitive properties such as the thick film forming property and the fine pattern forming property are extremely deteriorated.

  In the present invention, the average particle diameter of the inorganic filler can be determined as a MV value (Mean Volume Diameter) by a laser diffraction particle size distribution meter (for example, Nikkiso Co., Ltd., trade name: Microtrack MT3000). The inorganic filler can be measured and analyzed by dispersing it in water using phosphinates as a dispersant. In the present invention, when the volume average particle diameter of the inorganic filler is less than 5 μm, the photosensitive characteristics are improved as in the case where the aspect ratio is small, but the moisture absorption and moisture permeation reduction effects to the photosensitive resin are improved. Cannot be obtained so much, and in addition, the effect of increasing the elastic modulus is reduced. On the other hand, when the volume average particle diameter exceeds 50 μm, the photosensitive properties such as thick film formability and fine pattern formability are extremely deteriorated.

  In the present invention, both the average aspect ratio and the volume average particle diameter of the inorganic filler need to satisfy the ranges of 30 to 100 and 5 to 50 μm, respectively. Even if the average aspect ratio is in the range of 30 to 100, if the volume average particle diameter is less than 5 μm or exceeds 50 μm, the photosensitive properties such as thick film formability and fine pattern formability, and the heat and moisture resistance of the cured resin and high It is impossible to achieve compatibility with the elastic modulus. Moreover, even if the volume average particle diameter of the inorganic filler is in the range of 5 to 50 μm, if the average aspect ratio is less than 30 or exceeds 100, the effect of the present invention cannot be achieved as described above.

  The present invention places particular emphasis on improving the shape maintenance and reliability during manufacture and use in hollow structure devices. Therefore, the inorganic filler can exhibit the effect of the present invention if the average aspect ratio and the volume average particle diameter are in the range of 30 to 100 and 5 to 50 μm, respectively, but the average aspect is set to more than 50 and 100 or less. In this case, it is particularly preferable because the above-described shape maintenance and reliability can be greatly improved without significantly reducing the photosensitive characteristics. In that case, if the volume average particle diameter of the inorganic filler is in the range of 5 to 50 μm, there is no problem in achieving the effect of the present invention.

  In the photosensitive resin composition of the present invention, specific examples of the inorganic filler include talc, mica, boron nitride, kaolin, barium sulfate, and the like, among which scale-like mica is preferable. Mica has a large aspect ratio and high shape uniformity, so it not only reduces moisture permeability to the photosensitive resin composition, but also increases mold resistance by increasing the modulus of elasticity. This has the effect of suppressing the decrease in the amount compared to other inorganic fillers. Further, mica includes synthetic mica, and other natural inorganic fillers with less impurities can be obtained, so that the inhibition of photocurability can be reduced. In addition, since it is possible to suppress a decrease in moisture resistance caused by impurities contained in the inorganic filler, the reliability of the hollow structure device can be greatly improved.

  In the present invention, in order to make the inorganic filler have the above average aspect ratio and volume average particle diameter, a commercially available product having such characteristics may be purchased and used as it is, or a plurality of commercially available products may be mixed by themselves. It may be used after being processed, or may be used after being processed by classifying a commercially available product through a sieve. For example, as a commercially available product of mica, various mica manufactured by Yamaguchi Mica Industry Co., Ltd. can be used. As specific examples, A-51S (average aspect ratio 85, volume average particle size 52 μm), SYA-31RS ( Average aspect ratio 90, volume average particle diameter 40 μm), SYA-21RS (average aspect ratio 90, volume average particle diameter 27 μm), SJ-005 (average aspect ratio 30, volume average particle diameter 5 μm), etc. Can be used.

  When the photosensitive resin composition of the present invention is applied as a cover material for a hollow structure device, the content of the inorganic filler is usually not required to have a strict pattern accuracy. It can be determined by a balance with photosensitive properties such as film forming properties and fine pattern forming properties. However, when applied as a rib material of a hollow structure device, since fine pattern accuracy is usually required, the content of the inorganic filler is 5 to 50 mass based on the total solid content of the photosensitive resin composition. %, More preferably 20 to 50% by mass, still more preferably 20 to 45% by mass, and particularly preferably 20 to 40% by mass. When the content of the inorganic filler is 20 to 50% by mass, the thick film formation and pattern shape of the photosensitive resin composition are improved, sufficient resin strength is obtained, and desired physical properties and characteristics as a cured resin product are obtained. Can be obtained. When content of an inorganic filler is less than 20 mass% or exceeds 50 mass%, both characteristics cannot be made compatible. In the case where the photosensitive resin composition of the present invention is applied to the lid member, the content of the inorganic filler is preferably set to 5 to 60% by mass, more preferably 20 to 50% by mass, and more preferably 20 to 40%. It is particularly preferable that the content is% by mass.

  Further, (E) a sensitizer can be further added to the photosensitive resin composition of the present invention. (E) Examples of sensitizers include pyrazolines, anthracenes, coumarins, xanthones, oxazoles, benzoxazoles, thiazoles, benzothiazoles, triazoles, stilbenes, triazines, thiophenes, And phthalimides. These (E) sensitizers are used individually by 1 type or in mixture of 2 or more types.

  It is preferable that content of the said (E) sensitizer is 0.1-1 mass% on the basis of the solid content whole quantity of the photosensitive resin composition. (E) When the content of the sensitizing dye is within the above range, the sensitivity of the photosensitive resin composition is improved and the compatibility with the solvent is improved.

  Moreover, (F) heat resistant polymer can be further added to the above-mentioned photosensitive resin composition. (F) As the heat-resistant polymer, for example, polyimide, polyoxazole and their precursors, novolak resins such as phenol novolak and cresol novolak, polyamideimide, polyamide and the like having high heat resistance are preferable from the viewpoint of workability. These are used alone or in combination of two or more.

  The content of the (F) heat-resistant polymer is preferably 1 to 50% by mass based on the total solid content of the photosensitive resin composition. (F) When the content of the heat resistant polymer is in the above range, the heat resistance and resin strength of the photosensitive resin composition are good, and the developability is also good.

  Moreover, (G) thermal acid generator can be further added to the above-mentioned photosensitive resin composition. (G) As a thermal acid generator, the salt formed from strong acids, such as onium salt, and a base, an imide sulfonate, etc. are mentioned, for example. Examples of onium salts include diaryliodonium salts such as aryldiazonium salts, diphenyliodonium salts, diaryliodonium salts, di (alkylaryl) iodonium salts such as di (t-butylphenyl) iodonium salts, and trimethylsulfonium salts. Trialkylsulfonium salts, dialkylmonoarylsulfonium salts such as dimethylphenylsulfonium salt, diarylmonoalkyliodonium salts such as diphenylmethylsulfonium salt, and triarylsulfonium salts.

  0.1-30 mass parts is preferable with respect to 100 mass parts of (B) component, as for the compounding quantity of a thermal acid generator, 0.2-20 mass parts is more preferable, and 0.5-10 mass parts is further more preferable. .

  The photosensitive resin composition of the present embodiment includes (A) a thermal crosslinking material and (B) a photopolymerizable compound, (C) a photopolymerization initiator, and (D) an average aspect ratio of 30 to 30 as necessary. 100 and an inorganic filler having a volume average particle diameter of 5 to 50 μm and other materials such as (E) sensitizer, (F) heat-resistant polymer, and (G) thermal acid generator are mixed with a solvent. Can be obtained.

  Although it does not restrict | limit especially as a solvent used at this time, For example, the polar solvent which has N-methyl-2-pyrrolidone, N, N-dimethylacetamide, N, N-dimethylformamide, propylene glycol monomethyl ether acetate etc. as a main component And a solvent such as γ-butyrolactone. These solvents are used alone or as a mixture of two or more.

  Moreover, in order to improve the adhesiveness of the photosensitive resin composition and a board | substrate as needed, you may add an adhesion assistant to the photosensitive resin composition. Examples of the adhesion assistant include silane coupling agents such as γ-glycidoxysilane, aminosilane, and γ-ureidosilane.

(Photosensitive film)
The photosensitive resin composition is a two-layer photosensitive film in which a photosensitive resin layer is formed by applying an organic film such as polyethylene terephthalate as a supporting film by various known methods and drying to remove the solvent. (Dry film resist). Furthermore, it is good also as a three-layer photosensitive film which laminated | stacked on it as a protective film polyethylene terephthalate, a polyethylene film, a polypropylene film, etc. If the photosensitive resin layer has self-indicating properties, the support film can be peeled off to form a single-layer photosensitive film.

  When the photosensitive film of the present invention is used as a cover having a hollow structure, as described later, the support film may be peeled off after photopolymerization by light irradiation, or may be used as it is together with the photosensitive resin composition. Can be used as a lid material. In the present invention, a transparent or translucent heat-resistant plastic (such as a thermoplastic engineering plastic or a thermosetting resin having a three-dimensional network structure), glass, ceramic, or the like can be used instead of the support film. By using these heat-resistant plastics, glass or ceramics in the form of a thin film or thin plate, a film or thin plate in which a photosensitive resin composition is laminated can be formed in the same manner as the support film. In addition, these heat-resistant plastics, glass, or ceramics have a function of enhancing and reinforcing the shape maintenance property and rigidity of the lid.

  When the photosensitive film is used, the thickness is not particularly limited, but the supporting film or the supporting thin plate is preferably 10 μm to 3 mm, the photosensitive resin layer is preferably 1 to 500 μm, and the protective film is preferably 10 to 200 μm. Since the thickness of the support film or the support thin plate is appropriately determined from the shape and thickness of the hollow structure device and the point of manufacture, the usable range is wide.

(Rib pattern forming method)
Next, the rib pattern forming method of this embodiment will be described. In the rib pattern forming method of the present embodiment, a laminating step of laminating a photosensitive resin layer (photosensitive resin film) formed using the above-described photosensitive resin composition or photosensitive film on a substrate; An exposure step of irradiating a predetermined portion of the photosensitive resin layer with an actinic ray through a mask to photo-cure the exposed portion, a removing step of removing a portion other than the exposed portion of the photosensitive resin layer using a developer, and photosensitivity A desired pattern can be formed through a thermosetting process in which the exposed portion of the resin layer is thermally cured to form a cured resin.

  Hereinafter, each step will be described.

In the lamination step, a photosensitive resin film can be formed by applying and drying or laminating the above-described photosensitive resin composition or photosensitive film on a support substrate. Examples of the support substrate include a glass substrate, a semiconductor, a metal oxide insulator (for example, TiO ₂ , SiO _2, etc.), silicon nitride, a ceramic piezoelectric substrate, and the like. Examples of the method for applying the photosensitive resin composition include, but are not limited to, spin coating using a spinner, spray coating, dip coating, roll coating, and the like. In the case of a photosensitive film, it can be laminated using a laminator or the like.

  The coating thickness of the photosensitive resin composition varies depending on the coating means, the solid content concentration and the viscosity of the photosensitive resin composition, etc., but usually the film thickness of the dried film (photosensitive resin layer) is 1 to 500 μm, Preferably, it is applied so as to be 1 to 300 μm. In order to make the film thickness after drying become 1 to 300 μm, it is preferable to dissolve the above-mentioned photosensitive resin composition with a solvent and adjust the viscosity to 0.5 to 20 Pa · s. It is more preferable to adjust to 10 Pa · s. Further, the solid content concentration of the photosensitive resin composition is preferably 20 to 70% by mass, and more preferably 30 to 60% by mass. The resolution is good when the film thickness of the resulting coating is 300 μm or less. When using a photosensitive film, it can form beforehand so that the film thickness of the photosensitive resin layer may become said film thickness.

  Then, the photosensitive resin film can be formed on the support substrate by drying for 1 minute to 1 hour in a range of 60 to 120 ° C. using a hot plate, an oven, or the like.

  Next, in the exposure step, the photosensitive resin film formed as a film on the support substrate is irradiated with actinic rays on a predetermined portion through a negative mask having a desired pattern as necessary, and the exposed portion is photocured.

  Here, examples of the actinic rays used for exposure include ultraviolet rays, visible rays, electron beams, and X-rays. Among these, ultraviolet rays and visible rays are particularly preferable.

  Next, as a removal process, after forming a pattern by removing a portion other than the exposed portion (unexposed portion) of the photosensitive resin layer using an organic solvent-based or alkaline aqueous solution-based developer, the photosensitive resin layer The exposed portion is thermally cured to form a pattern made of a cured resin.

  Here, as the developing solution, an organic solvent such as N-methylpyrrolidone, ethanol, cyclohexanone, cyclopentanone, propylene glycol methyl ether acetate can be used. Moreover, alkaline aqueous solution, such as sodium hydroxide, potassium hydroxide, sodium silicate, ammonia, ethylamine, diethylamine, triethylamine, triethanolamine, tetramethylammonium hydroxide, can be used. Among these, it is preferable to use propylene glycol methyl ether acetate from the viewpoint of development speed.

  Further, after development, it is preferable to rinse with water, alcohol such as methanol, ethanol or isopropyl alcohol, n-butyl acetate, propylene glycol monomethyl ether acetate, diethylene glycol dimethyl ether acetate or the like, if necessary.

  Furthermore, a thermosetting process is performed in which the exposed portion of the photosensitive resin layer is thermoset to form a cured resin. The thermosetting (curing) after development is preferably carried out for 1 to 2 hours while selecting the temperature and gradually increasing the temperature. It is preferable to perform thermosetting at 120-240 degreeC. When the heating temperature is raised stepwise, for example, after heat treatment at 120 ° C. and 160 ° C. for 10 to 50 minutes (preferably about 30 minutes), then heat treatment at 220 ° C. for 30 to 100 minutes (preferably about 60 minutes) It is preferable to carry out.

(Method for forming hollow structure)
The rib pattern made of the cured resin formed by the above-described forming method has a sufficient film thickness, and a hollow structure is formed by covering a ceramic substrate, Si substrate, glass substrate, metal substrate, etc. as a lid. You can also

  In the present invention, the photosensitive resin composition of the present invention or a photosensitive film formed from the photosensitive resin composition of the present invention can be used not only as the above-mentioned hollow structure rib part but also as a lid part. For example, the photosensitive resin composition once formed into a film or a photosensitive film that has been preliminarily formed is pasted and laminated on the above pattern, and then an exposure process, and a development process (removal process) as necessary. A hollow structure can be formed through a thermosetting process. When applying the photosensitive resin composition or photosensitive film of the present invention as a lid, it is not always necessary to go through a development process, but in the following cases, by adopting the development process, the hollow structure device of the present invention can be used. Usability is improved. For example, when it is desired to control the shape of the lid, or when simultaneously manufacturing a plurality of hollow structure devices at the same time, after exposing only the size corresponding to the lid of the individual hollow device through the mask, the surrounding unexposed For example, the portion is developed to be divided into individual pieces.

  The lamination step, the exposure step, the removal step, and the thermosetting step can be performed in the same manner as the method described in the description of the rib pattern forming method. The film thickness of the photosensitive resin layer for forming the lid is preferably 5 to 500 μm, and more preferably 10 to 400 μm. The final film thickness of the lid formed through the curing step is preferably 10 μm to 3 mm, and more preferably 20 μm to 2 mm. When the thickness of the lid is less than 10 μm, the shape cannot be maintained even when the highly rigid material according to the present invention is applied, and a large deformation occurs under the high temperature and high pressure conditions at the time of molding. On the other hand, if the thickness exceeds 3 mm, the hollow structure device becomes thick, or the light transmittance at the time of exposure is lowered, so that a problem in manufacturing is likely to occur. The thickness of the lid is not only the thickness of the photosensitive resin composition or photosensitive film of the present invention, but as described above, by leaving the supporting film or thin plate as a lid as it is, It can be adjusted to a desired thickness.

Moreover, adhesion | attachment with a cover part and a rib pattern can be performed by adhesion | attachment by thermocompression using a press machine, a roll laminator, and a vacuum laminator, etc., for example.
In the present invention, the rib pattern can be prepared without using the photosensitive resin composition of the present invention, and only the lid can be formed using the photosensitive resin composition of the present invention. It is preferable to use the photosensitive resin composition of the present invention for both the lid portions because of excellent adhesiveness therebetween. In particular, as the photosensitive resin composition used for both the rib pattern and the lid, the adhesiveness can be further improved by using a photopolymerizable compound having a similar content to that of the inorganic filler.

  As described above, according to the present invention, in the hollow structure forming step, a thick film rib pattern can be collectively formed by photolithography, and a cured product of the photosensitive resin composition formed into a film shape from the top (or A hollow structure can be formed by sealing a sealing substrate such as ceramic as a lid. In addition, since the inside of the hollow space is moisture-proof by the surrounding photosensitive resin composition and the hollow portion is maintained even at high temperatures, electronic components that require a hollow structure such as a SAW filter, CMOS / CCD sensor, MEMS, etc. It is useful for reducing the size, height and functionality of electronic components. The photosensitive resin composition of the present invention is particularly suitable for forming a rib part and a cover part of a hollow structure of a SAW filter, and is particularly suitable for forming a cover part in that high reliability can be achieved.

(SAW filter and manufacturing method thereof)

  The SAW filter and the manufacturing method thereof will be described. 1A to 1C are process diagrams showing a preferred embodiment of a SAW filter 100 and a method for manufacturing the SAW filter 100 according to the present invention.

  First, as shown in FIG. 1A, a photosensitive resin layer 32 formed using the photosensitive resin composition of the present invention is laminated on the substrate 10 on which the comb-shaped electrode 20 is formed. The lamination method can be the same as the method described in the rib pattern forming method.

  In the same manner as the rib pattern forming method, the applied film thickness is usually applied so that the film thickness (photosensitive resin layer) after drying is 1 to 300 μm.

  After coating the photosensitive resin composition on the substrate 10, the film is dried to obtain the photosensitive resin layer 32. Drying is preferably performed in the range of 60 to 120 ° C. for 1 minute to 1 hour using an oven, a hot plate, or the like.

  Next, as shown in FIG. 1A, a predetermined portion of the photosensitive resin layer 32 is irradiated with actinic rays through a negative mask 60 having a desired pattern as necessary, and the exposed portion is photocured. Here, examples of the actinic rays used for exposure include ultraviolet rays, visible rays, electron beams, and X-rays. Among these, ultraviolet rays and visible rays are particularly preferable.

  Next, as shown in FIG. 1B, after forming a pattern by removing a portion (unexposed portion) other than the exposed portion of the photosensitive resin layer 32 using an organic solvent-based developer, the photosensitive resin layer 32 is exposed to light. The exposed portion of the conductive resin layer 32 is thermally cured to form a rib portion 30 made of a cured resin. In these exposure process, removal process, and thermosetting process, the same method as the rib pattern forming method can be used.

  Next, as shown in FIG.1 (c), the cover part 40 is provided on the rib part 30, and a hollow structure is formed. Here, the cover part 40 can be produced using, for example, a film formed by previously forming the photosensitive resin composition of the present invention or a film formed beforehand as a photosensitive film. That is, these films can be attached to the top of the ribs 30 and then exposed, developed, and thermally cured to form the lid 40.

  Moreover, adhesion | attachment with the cover part 40 and the rib part 30 can be performed by adhesion | attachment by the thermocompression bonding etc. which used the roll laminator, for example.

  In addition, the cover part 40 may be comprised with materials other than the photosensitive resin composition of this invention. However, it is preferable that the cover part 40 is comprised with the material which is excellent in heat-and-moisture resistance and has a low water absorption rate. Moreover, as the lid portion 40, a sealing substrate such as ceramic can be used. In this case, at least a rib pattern formed from the photosensitive resin composition of the present invention is used as a rib material for forming the hollow structure of the SAW filter.

  On the other hand, when the photosensitive resin composition or the photosensitive film of the present invention is used for a lid for forming a hollow structure of a SAW filter, the rib portion is formed by a method other than using the photosensitive resin composition of the present invention. May be.

  After forming the rib portion and the lid portion using the photosensitive resin composition or the photosensitive film of the present invention, the electricity between the electrode 20 and the conductor wired inside the substrate 10 and the opposite surface of the electrode 20 FIG. 2 shows a SAW filter obtained by forming a plating and mounting a metal ball in order to make a general connection. The SAW filter shown in FIG. 2 can be used for a hollow structure device even under high-temperature reflow conditions when solder balls are mounted by applying the photosensitive resin composition or the photosensitive film having excellent shape maintenance, heat resistance and rigidity of the present invention. There is no deformation that affects the properties.

  As the substrate 10, for example, a piezoelectric substrate such as a lithium tantalate substrate, a lithium niobate substrate, or a gallium arsenide substrate is used. As a material of the comb electrode 20, for example, aluminum or the like is used. As the material of the wiring formed on the inside and the surface of the substrate, a metal conductor such as copper or aluminum or a metal conductor such as gold, silver, platinum or palladium is used in the case of a ceramic substrate. The metal ball may be, for example, a solder material such as tin-silver-copper or lead-tin, gold, or a resin ball whose surface is covered with a metal conductor.

  FIG. 3 is a schematic cross-sectional view showing another preferred embodiment of a SAW filter which is one of the electronic components of the present invention, and a method for manufacturing the same. FIG. 3 shows a method of forming the rib portion and the lid portion of the present invention only by UV exposure and a method of forming the rib portion and the lid portion of the present invention using both UV exposure and laser drilling. Laser drilling is used to shape the conductor inside the lid.

  In FIG. 3, a method for forming the rib portion and the lid portion only by UV exposure will be described first. After the steps of FIGS. 3A to 3B, a hollow space is formed on the wiring conductor 81 electrically connected to the aluminum comb electrode 20 on the substrate 10 by the same method as shown in FIG. The rib portion 30 is formed. Here, a hole 35 for forming an internal conductor is formed inside the rib portion 30 through a development process after UV exposure. Thereafter, the photosensitive resin composition or photosensitive film 41 of the present invention laminated on the support film is applied or placed on the rib portion 30, and UV exposure is performed through a mask ((c) in FIG. 3). . Since only the part corresponding to the diameter of the hole 35 for forming the internal conductor is shielded so as not to transmit light, the mask forms the lid part 40 that is light-cured at other parts. The unexposed portion of the lid portion 40 is subjected to development and then subjected to desmear processing and the like in order to completely penetrate the hole 35 inside the rim portion formed previously ((d) in FIG. 3). Further, an internal conductor is formed in the hole 35 formed in the rib portion and the lid portion by plating or the like, and a wiring is formed on the surface of the lid portion ((e) in FIG. 3). In the present invention, the hole 35 formed inside the rib portion and the lid portion is formed not only by the plating method but also by using a metal paste or a resin paste containing metal powder to form an internal conductor by a conductor filling method. Can do. Through these steps, the conductor 81 wired to the aluminum comb electrode 20 on the substrate 10 is electrically connected to the wiring conductor formed on the surface of the lid. Finally, a metal ball 70 is mounted on the surface of the lid by reflow or the like to obtain a SAW filter which is an electronic component having a hollow structure of the present invention ((f) of FIG. 3).

  Next, referring to FIG. 3, a method of forming the rib portion and the lid portion of the present invention using both UV exposure and laser drilling will be described. Basically, the formation method of the rib portion and the lid portion is the same as that in the case of only the UV exposure, but when forming the hole 35 for forming the inner conductor inside the lid portion, not the UV exposure, The difference is that the laser drilling method is applied. That is, in (c) of FIG. 3, after the photosensitive resin composition or photosensitive film 41 of the present invention laminated on the support film is applied or placed on the rib portion 30, (d) of FIG. In the step, a hole 35 for forming an internal conductor is formed inside the lid by a laser. Unlike the UV exposure, the laser drilling method does not require mask exposure or development, and can be applied to form an arbitrary pattern freely and in a short time. As the laser, a known laser such as a YAG laser, carbon dioxide laser, or excimer laser can be used. The manufacturing method of the SAW filter in the present invention is not limited to that shown in FIG. Either UV exposure or laser irradiation can be used by appropriately selecting one according to the thickness of the rib portion, the shape of the internal conductor formed inside the rib portion, and the cover surface wiring pattern.

The SAW filter hollow structure fabrication is completed through the above steps.
When the SAW filter produced as described above is sealed with a sealing material as shown in FIG. 4, it is generally performed in the following steps, but is not limited thereto.
(1) Set the SAW filter on the molding die.
(2) A solid sealing material tablet is set in the pot of the molding machine.
(3) The sealing material is melted under conditions of a mold temperature of 150 to 180 ° C., and pressure is applied to the mold (mold).
(4) The sealing of the SAW filter is completed by pressurizing for 30 to 120 seconds, opening the mold after the sealing material is thermally cured, and taking out the molded product.
Usually, the sealing with the sealing material is performed before the metal ball is mounted, and after the sealing, the metal ball is mounted on the opposite surface of the substrate by reflow. However, sealing with a sealing material may be performed after the metal ball is mounted. FIG. 4 shows one SAW filter sealed with a sealing material, but the SAW filter of the present invention seals a large number of SAW filters formed on one substrate with a sealing material. It can also be obtained by cutting into individual pieces after stopping. The manufacturing method is shown in FIGS. First, a large number of SAW filters are produced on one substrate, and a rib member and / or a lid member are formed using the photosensitive resin composition or photosensitive film of the present invention ((a) to (in FIG. 5). e)). Then, it seals with a sealing material collectively (FIG.5 (f)), and divides | segments into pieces by methods, such as a cutting | disconnection, and obtains the SAW filter 100 (FIG.5 (g)).

  At this time, the lid portion 40 and / or the rib portion 30 is required to have mold resistance at a mold temperature of 150 to 180 ° C. That is, when the cover part 40 and / or the rib part 30 are produced with the photosensitive resin composition, it is desirable that the cover part 40 and / or the rib part 30 is not deformed at a temperature of 150 to 180 ° C. In order to obtain, it is preferable that the glass transition temperature of the cover part 40 and / or the rib part 30 is 180 degreeC or more. The elastic modulus at 180 ° C. is preferably 1.2 GPa or more, more preferably 1.5 GPa or more, and particularly preferably 1.8 GPa or more. The upper limit of the elastic modulus at 180 ° C. is not particularly limited, but is 10 GPa or less from a practical viewpoint. In the present invention, the above elastic modulus is not only specified to increase mold resistance, but is also a necessary physical property value for preventing the rib material from falling and sagging or maintaining the flatness of the lid material.

  As described above, according to the present invention, in the SAW filter manufacturing process, a thick film rib pattern can be collectively formed on a piezoelectric substrate by photolithography using a solvent developer, and further, a film is formed as a lid from above. A hollow structure can be formed by sealing with a cured product of the photosensitive resin composition (or a sealing substrate such as ceramic). Further, since the inside of the hollow space is moisture-proof by the surrounding resin composition, corrosion of the aluminum electrode can be suppressed. Moreover, since this resin composition has a high elastic modulus at a high temperature, the hollow structure can be maintained even at the temperature and pressure during the sealing resin molding.

  EXAMPLES Hereinafter, although this invention is demonstrated more concretely based on an Example and a comparative example, this invention is not limited to a following example.

[Examples 1 to 18 and Comparative Examples 1 to 4]
Tables 1 and 2 below show (A) a thermally crosslinkable compound, (B) a photopolymerizable compound having at least one ethylenically unsaturated group, (C) a photopolymerization initiator, and (D) an inorganic filler, respectively. It mixed by the mixing | blending ratio (mass part) which obtained the solution of the photosensitive resin composition of Examples 1-18 and Comparative Examples 1-4. In addition, the number in Table 1 and Table 2 has shown the mass part of solid content. Moreover, each component in Table 1 and Table 2 is shown below.

Nicarak MW-30HM (trade name, Sanwa Chemical Co., Ltd.)

Nicarak MW-750LM (trade name, Sanwa Chemical Co., Ltd.)

Nikarak MX-270 (trade name, Sanwa Chemical Co., Ltd.)

Nikarak MX-290 (trade name, Sanwa Chemical Co., Ltd.)

TML-BPA-MF (trade name, Honshu Chemical Industry Co., Ltd.)

DMOM-PTBP (trade name, Honshu Chemical Industry Co., Ltd.)

Multifunctional bisphenol A novolac type epoxy resin (trade name Epicron N-865, manufactured by Dainippon Ink & Chemicals, Inc.), amide methacrylate (synthetic product), amide acrylate (synthetic product), UN-952 (trade name, urethane acrylic oligomer, Negami Kogyo Co., Ltd.), A-DPH (trade name, dipentaerythritol hexaacrylate, Shin-Nakamura Chemical Co., Ltd.), I-OXE01 (trade name, 1,2-octanedione-1- [4- (phenylthio) ) Phenyl] -2- (O-benzoyloxime, manufactured by Ciba Specialty Chemicals Co., Ltd.), cationic polymerization initiator (diphenyl [4- (phenylthio) phenyl] sulfonium trifluorotrispentafluoroethyl phosphate),
The following two types of mica A and mica B as inorganic fillers: Mica A (aspect ratio 90, volume average particle size 27 μm)
・ Mica B (aspect ratio: 30, volume average particle size: 5 μm)

[Synthesis of amide methacrylate]
In a 1-liter reaction vessel equipped with a thermometer and a stirrer, 380.0 g (2.0 mol) of 1,3-phenylenebisoxazoline and 228.0 g (1.0 mol) of bisphenol A were added and stirred at 150 ° C. for 10 hours. . Thereafter, 500 ppm of methoquinone and 172.2 g (2.0 mol) of methacrylic acid were added and stirred at 100 ° C. for 6 hours, 190 g of dimethylacetamide was added dropwise, and further stirred at 100 ° C. for 6 hours, and the acid value was 1.1 mgKOH / g. Then, the stirring was stopped to obtain a solution of a compound represented by the following formula (11) which is a photopolymerizable unsaturated compound. The solid content of the obtained solution was 80% by mass.

[Synthesis of amide acrylate]
An amide acrylate was synthesized by the same method as in the case of the amide methacrylate except that 144.0 g (2 mol) of acrylic acid was used instead of methacrylic acid. The solid content of the obtained solution was 80% by mass.

<Evaluation of resolution>
The photosensitive resin composition solutions of Examples and Comparative Examples were uniformly applied on a silicon substrate using a spin coater, dried on a hot plate at 90 ° C. for 5 minutes, and the dried photosensitive resin having a film thickness of 30 μm. A layer was formed. About the test board | substrate which formed this photosensitive resin layer, the exposure amount 200mJ / cm using the proximity exposure machine (brand name: UX-1000SM) by USHIO INC. Through the negative mask which has an opening pattern with a hole diameter of 60 micrometers. ^{In step 2} , the photosensitive resin composition layer was exposed. The test substrate was developed by being immersed in propylene glycol monomethyl ether acetate, which is an organic solvent developer, for 3 minutes. The developed resist pattern was washed with n-butyl acetate, observed after drying, and the solvent resistance was evaluated based on the following criteria. The results are shown in Tables 1 and 2.
A: A hole diameter of 60 μm is opened and there is no residue after development.
B: A hole diameter of 60 μm is opened, but there is a residue after development.
C: Hole diameter 60 μmφ is not open. Or pattern formation is impossible.

<Hollow retention>
The photosensitive resin composition solutions of Examples and Comparative Examples were uniformly applied on a silicon substrate using a spin coater, dried on a hot plate at 90 ° C. for 5 minutes, and the dried photosensitive resin having a film thickness of 30 μm. A layer was formed. About the test board | substrate which formed this photosensitive resin composition layer, the exposure amount using the proximity exposure machine (brand name: UX-1000SM) made from USHIO INC. Through the negative mask which has a lattice size 1mm □ opening pattern The photosensitive resin layer was exposed at 200 mJ / cm ² . This test substrate was developed and cured to obtain a cured film pattern having openings in a lattice pattern.

  To this, a photosensitive resin composition was formed using a polyethylene phthalate film having a thickness of 50 μm as a support film, and a photosensitive film having a photosensitive resin layer thickness of 30 μm was pasted thereon to form a hollow structure. Formed.

Next, in order to maintain the flatness of the photosensitive film laminated on the support film, the exposure amount was applied using a proximity exposure machine (trade name: UX-1000SM) manufactured by USHIO INC. With tension applied in two axial directions. The film-shaped photosensitive resin film was exposed at 200 mJ / cm ² . This test substrate was cured at 120 ° C. for 30 minutes, at 160 ° C. for 30 minutes, and at 220 ° C. for 60 minutes, and then the support film was peeled off, and the cross-section of the cured lattice pattern was observed with a microscope. The hollow retention was evaluated based on the above criteria. The results are shown in Tables 1 and 2.
A: The hollow part can be retained, and the cured film is not dripped at all. B: The hollow part is retained, but the film is slightly sagged. C: The film is dripped and the hollow part is removed. Crushed

<Measurement of elastic modulus at high temperature (mold pressure resistance alternative evaluation) and measurement of glass transition temperature>
The photosensitive resin composition solutions of Examples and Comparative Examples were uniformly applied on a silicon substrate using a spin coater, dried on a hot plate at 90 ° C. for 5 minutes, and the dried photosensitive resin having a film thickness of 30 μm. A composition layer was formed. About the test board | substrate which formed this photosensitive resin composition layer, exposure of the photosensitive resin composition layer was carried out with the exposure amount of 200 mJ / cm < ² > using the proximity exposure machine (brand name: UX-1000SM) made by Ushio Electric. And photocured. The photosensitive resin composition layer was cured by heating at 120 ° C. for 30 minutes, 160 ° C. for 30 minutes, and 220 ° C. for 60 minutes. The cured film of the obtained photosensitive resin composition was peeled from the silicon substrate, and the elastic modulus at 180 ° C. and the glass transition temperature of the peeled cured film were measured by a viscoelasticity tester (trade name: RSA-III, manufactured by TA instruments). It was measured by. The measurement was performed under the conditions of test mode: tension, test temperature: room temperature to 300 ° C., heating rate: 5 ° C./min, test frequency: 1 Hz, and distance between chucks: 20 mm. These results are shown in Tables 1 and 2.

<Evaluation of heat and humidity resistance>
The photosensitive resin composition solutions of Examples and Comparative Examples were uniformly applied on a silicon substrate using a spin coater, dried on a hot plate at 90 ° C. for 5 minutes, and the dried photosensitive resin having a film thickness of 30 μm. A composition layer was formed. About the test board | substrate which formed this photosensitive resin composition layer, exposure of the photosensitive resin composition layer was carried out with the exposure amount of 200 mJ / cm < ² > using the proximity exposure machine (brand name: UX-1000SM) made by Ushio Electric. And photocured. Thereafter, the photosensitive resin composition layer was cured by heating at 120 ° C. for 30 minutes, 160 ° C. for 30 minutes, and 220 ° C. for 60 minutes. The test substrate was allowed to stand for 100 hours under the conditions of 121 ° C., 100% RH, 2 atm, and then the appearance of the cured film was visually evaluated. Further, the adhesion was in accordance with JIS K5400 (1990). It was evaluated in a test. The evaluation criteria are as follows. The results are shown in Tables 1 and 2.

(appearance)
A: Turbidity, peeling, swelling, and cracks are not observed in the cured film.
B: Any one of slight turbidity, peeling, swelling and cracking is observed in the cured film.
C: Any one of turbidity, peeling, swelling, and cracks in the cured film is observed.

(Cross cut test)
The remaining mass after peeling the tape
A: 100/100 (no peeling)
B: ≧ 90/100 (1-10 mass peeling)
C: <90/100 (exfoliation is more than 10 squares)

  As shown in the examples of Table 1 and Table 2, it contains (A) a thermally crosslinkable compound, (B) a photopolymerizable compound having at least one ethylenically unsaturated group, and (C) a photopolymerization initiator. And (A) the content of the thermally crosslinkable compound is composed of the (A) condensation-reactive thermally crosslinkable compound and the (B) photopolymerizable compound having at least one ethylenically unsaturated group. When the product is 100 parts by mass, the photosensitive resin composition containing 10 to 40 parts by mass of the photosensitive resin composition has an evaluation of each property of A or B or more, and exhibits excellent effects. .

  In the photosensitive resin composition of the present invention, when a phenol resin or an epoxy resin is used as the thermally crosslinkable compound (A), the resolution due to light exposure and the moist heat resistance under severe high temperature and high humidity tend to decrease. For hollow structure devices that require stricter reliability, it is necessary to carefully determine the lifetime (Examples 5 to 7). (A) When a thermally crosslinkable compound having at least one methylol group or alkoxyalkyl group is used as the thermally crosslinkable compound, excellent resolution by light exposure can be obtained (Examples 1 to 4, 9 to 10, 15). 16). This is considered because (A) the compatibility of the thermally crosslinkable compound having at least one methylol group or alkoxyalkyl group and (B) the photopolymerizable compound having at least one ethylenically unsaturated group is improved. . Among these, by applying a melamine resin or urea resin in which the N-position is substituted with a methylol group and / or an alkoxymethyl group, the photosensitivity improves not only the resolution but also the heat and humidity resistance under severe high temperature and high humidity. Resin compositions can be obtained (Examples 1-2, 9-10, 15-16).

  Further, when 100 parts by mass of a composition comprising (A) a condensation-reactive thermally crosslinkable compound and (B) a photopolymerizable compound having at least one ethylenically unsaturated group, (A) thermal crosslinking When the content of the functional compound decreases, the high-temperature elastic modulus cannot be increased, and not only the hollow retainability but also the heat and humidity resistance tend to decrease (Example 8). When the content of the heat-crosslinkable compound (A) is less than 10 parts by mass, the heat and moisture resistance declines significantly, and cannot be applied as a material for the rib part and the lid part of the hollow structure device (comparison) Examples 1-2). On the contrary, when the content of the (A) heat crosslinkable compound is increased, the hollow retainability is improved and the high-temperature elastic modulus is increased, but the resolution by light exposure tends to be reduced (Example 11). . When the content of the (A) thermally crosslinkable compound exceeds 40 parts by mass, the resolution is significantly lowered by light exposure, and a fine pattern cannot be formed in the hollow structure device. Moreover, since the cured product of the photosensitive resin composition itself has lost the flexibility of the resin and the adhesiveness tends to be lowered, the heat and humidity resistance is lowered (Comparative Example 3).

  In the present invention, (B) as a photopolymerizable compound having at least one ethylenically unsaturated group, a resin composition comprising amide methacrylate or acrylate not containing amide acrylate is a resin composition containing amide methacrylate or amide acrylate. Therefore, it is necessary to carefully determine the lifetime of a hollow structure device that requires higher reliability (Example 14). . In addition, the conventional photosensitive resin composition composed of a photosensitive epoxy resin and a photopolymerization initiator cannot be used as a rib material and / or a lid material for a hollow structure device because the heat-and-moisture resistance is greatly reduced. (Comparative Example 4).

  The photosensitive resin composition of the present invention contains an inorganic filler having an average aspect ratio of 30 to 100 and a volume average particle diameter of 5 to 50 μm, so that the high-temperature elastic modulus can be obtained without reducing the optical resolution. As well as suppressing the shrinkage during resin curing, there are additional effects such as improving the strength of the cured resin and reducing the thermal expansion coefficient. Therefore, when it applies as a rib part and a cover part, the stress which generate | occur | produces in resin hardened | cured material can be reduced and a highly reliable hollow structure device can be produced (Examples 17-18).

  As described above, in the present invention, a photosensitive resin composition containing a thermally crosslinkable compound having at least one methylol group or alkoxyalkyl group and a photopolymerizable compound having at least one ethylenically unsaturated group, In addition, since the photosensitive film is excellent in heat and moisture resistance, the cured product has a high elastic modulus at high temperature, and is excellent in hollow structure retention, it can be used as a rib material and / or a lid material for a hollow structure device.

  According to the present invention, by applying a photosensitive resin composition excellent in workability and reliability, and a photosensitive film using the same to a rib pattern forming method and a hollow structure forming method, at a low cost, and A highly reliable electronic component having a hollow structure, specifically, a SAW filter can be manufactured.

  DESCRIPTION OF SYMBOLS 10 ... Board | substrate, 20 ... Aluminum comb electrode, 30 ... Rib part, 32 ... Photosensitive resin composition layer for rib parts, 35 ... Hole for forming an internal conductor, 40. .. Lid portion, 41... Photosensitive resin composition for lid portion, 60... Mask, 70... Metal ball, 80. -Sealing material, 100 ... SAW filter.

Claims (11)

A photosensitive resin composition used as a rib member or a lid member for forming a hollow structure in an electronic component having a hollow structure, comprising (A) a thermally crosslinkable compound and (B) at least one ethylenically unsaturated group Containing a photopolymerizable compound, (C) a photopolymerization initiator, and (D) an inorganic filler having an average aspect ratio of 30 to 100 and a volume average particle diameter of 5 to 50 μm,
And the content of the (A) thermally crosslinkable compound is 100 parts by mass of the total amount of the (A) thermally crosslinkable compound and the (B) at least one ethylenically unsaturated group. Sometimes, the photosensitive resin composition which is 10-40 mass parts.   The photosensitive resin composition according to claim 1, wherein the (A) heat-crosslinkable compound is a condensation-reactive heat-crosslinkable compound.   The photosensitive resin composition according to claim 2, wherein the (A) condensation-reactive thermally crosslinkable compound is a compound having at least one methylol group or alkoxyalkyl group.   The photosensitive resin composition according to claim 2, wherein the (A) thermally crosslinkable compound is a melamine resin or urea resin substituted at the N-position with a methylol group and / or an alkoxymethyl group.   The photosensitive resin composition according to claim 1, wherein the photopolymerizable compound (B) having at least one ethylenically unsaturated group is an acrylate compound or a methacrylate compound containing an amide group. It is a photosensitive film used as a lid | cover material or rib material for forming the said hollow structure in the electronic component which has a hollow structure, Comprising: The photosensitive resin composition in any one of Claims 1-5 in a film form A photosensitive film formed by molding. A photosensitive resin layer laminating step of laminating the photosensitive resin composition according to any one of claims 1 to 5 or the photosensitive film according to claim 6 on a substrate, and a predetermined portion of the photosensitive resin layer. An exposure step of irradiating actinic rays through a mask to photocure the exposed portion, a removal step of removing a portion other than the exposed portion of the photosensitive resin layer using a developer, and the step of removing the photosensitive resin layer. A rib pattern forming method for forming a hollow structure, comprising: a thermosetting step of forming a cured resin by thermally curing an exposed portion. On rib pattern provided to form a hollow structure on a substrate, a photosensitive resin composition according to any one of claims 1 to 5 so as to form a lid portion of the hollow structure or according to claim 6, wherein A photosensitive resin layer laminating step of laminating a photosensitive film; an exposure step of irradiating a predetermined portion of the photosensitive resin layer with an actinic ray to photocure an exposed portion; and if necessary, the photosensitive resin layer A method for forming a hollow structure, comprising: a removing step of removing a portion other than an exposed portion using a developer; and a thermosetting step of thermally curing the exposed portion of the photosensitive resin layer to form a cured resin. Method for forming a hollow structure according to claim 8, wherein the rib pattern provided to form the hollow structure and is formed by the method of claim 7 wherein said substrate. The electronic component which has a hollow structure in which the rib part or cover part of a hollow structure is formed using the photosensitive resin composition in any one of Claims 1-5 , or the photosensitive film of Claim 6 . The electronic component according to claim 10 , which is a surface acoustic wave filter.

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