JP6471740B2 - Photosensitive resin composition, photosensitive film, pattern forming method, hollow structure forming method, and electronic component - Google Patents

Description

  The present invention relates to a photosensitive resin composition, a photosensitive film using the same, a 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, it is necessary to have a hollow structure so that other objects do not contact a particularly functionally important part 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. Have. In addition, a MEMS (Micro Electro Mechanical System) for high frequency applications such as a gyro sensor and a millimeter wave radar has a hollow structure in order to protect a movable part.

In an element that is required to have such a hollow structure, conventionally, a hollow structure is formed by processing and joining inorganic materials. However, a method for forming a hollow structure having a frame portion and / or a lid portion formed of resin is considered in order to reduce costs by reducing the number of parts and man-hours and to reduce the size and height of the structure. It has become. In particular, by using a photosensitive resin material, the shape of the hollow structure and the formation of the hole for forming the electrode portion are facilitated by the photolithography technique, and a very large cost reduction effect is obtained.
In Patent Documents 1 to 3, in an electronic component having a hollow structure, as a photosensitive resin material for an outer wall portion (frame portion) and / or a ceiling portion (lid portion) for forming a hollow portion, photosensitive polyimide, The use of a photosensitive epoxy resin or a resin film thereof is described.

  On the other hand, an electronic component having a hollow structure such as a surface acoustic wave device (SAW device) is a package having an external terminal or an external electrode that is electrically connected to a wiring electrode of a piezoelectric substrate in order to be mounted on a mounting substrate. Manufactured as a structure. At that time, the periphery of the frame portion and the lid portion forming the hollow portion is often resin-sealed by, for example, a transfer molding method in order to improve the handleability as well as the protection of the elements (for example, Patent Documents 4 to 4). 7).

  The surface acoustic wave device may be used as a modularized electronic component that is mounted on the same substrate together with a plurality of elements such as an IC as an electronic device mounted on a portable terminal telephone device or the like. In order to protect each element mounted on the same substrate, this modularized electronic component is manufactured by a transfer molding method using a semiconductor sealing material, a vacuum laminating method using a photosensitive epoxy resin, or a vacuum press method. Is sealed with resin (for example, Patent Documents 8 to 9).

Resin sealing by transfer molding is usually performed at a high temperature and high pressure (150 to 200 ° C., 50 to 150 kg / cm ² ), so that a high pressure is applied to the element mounted on the substrate. As a result, the frame part and the lid part forming the hollow part are deformed, and there arises a problem that the piezoelectric substrate comes into contact with the wiring electrode and a large distortion occurs in the vibration space. In the above Patent Documents 4 to 8, various methods for solving such a problem of deformation of the hollow structure are proposed.

  Patent Document 9 discloses a method of lowering the elastic modulus of the second sealing portion provided around the first sealing portion with respect to the first sealing portion forming a cavity (hollow). Has been.

  Furthermore, a structure in which a hollow frame portion and / or lid portion is formed using a photosensitive resin is a method close to a wafer level package in which electronic components such as a surface acoustic wave device are collectively manufactured using a single substrate. It is known that it can be manufactured (see Patent Document 2, 6 to 8). The package manufactured in a batch of substrates can greatly reduce the manufacturing cost, and Patent Documents 10 to 12 disclose the structure and manufacturing method thereof.

JP 2010-10812 A Special table 2003-523082 gazette JP 2008-250200 A JP 2007-142770 A JP 2001-185976 A JP 2009-200996 A JP 2009-2127760 A International Publication No. 2009/057699 JP 2007-208665 A JP 2009-117730 A International Publication No. 2008/018452 International Publication No. 2010/061821

  However, although the epoxy resin or polyimide resin disclosed as the photosensitive resin in Patent Documents 1 to 12 is a general-purpose material conventionally used in the field of photolithography technology, it has a fine and strong hollow structure. There is no specific report on whether the material can form a hollow structure and whether the resin can sufficiently secure the shape retention of the hollow structure at high temperatures and various reliability as an electronic component. None of these studies have been done.

  In general, photosensitive resins have a limited range of materials compared to thermosetting resins that are cured only by heating. Therefore, a composition that has excellent heat and humidity resistance and adhesion to the substrate can be used for thermosetting. Difficult compared to the functional resin. That is, in the case of a photosensitive epoxy resin, the moisture absorption rate and moisture permeability rate tend to be higher than those of a thermosetting epoxy resin, and sufficient moisture and heat resistance cannot be obtained, and the desired reliability as a hollow structure device is ensured. There is a problem that can not be.

  Further, in the above-mentioned patent document, no specific examination is made on the elastic modulus of the photosensitive epoxy resin at a high temperature after photocuring. Therefore, when the photosensitive epoxy resins described in those patent documents are used, deformation, sagging, or dents of the resin occur during production or use, and the hollow structure retainability is impaired, resulting in significant damage. It is possible to suffer. 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, if the hollow structure is pressurized under high temperature and high pressure conditions, Since there is a high possibility that the structure will be crushed, there are uneasy points in maintaining the shape and electrical characteristics, which is a big problem.

  In addition, these photosensitive epoxy resins are not only deformable but also prone to cracking and peeling in the high temperature repetitive process during solder reflow performed when mounted on a substrate. Had. In addition, in photolithography using a photosensitive epoxy resin, it is common to form a pattern with an opening diameter of 100 μm or more. The above-mentioned patent document does not disclose the fine pattern forming property below that, and it is unclear whether a fine pattern can be formed by the photosensitive epoxy resin.

On the other hand, the photosensitive polyimide resin mentioned as the photosensitive resin having high heat resistance and high reliability in the above patent document generally has a problem that it is difficult to form a film having a thickness of 10 μm or more. Therefore, when a photosensitive polyimide resin is used, it is difficult to form a sufficient thickness necessary for forming a rib having a hollow structure. Rib formation with a thick film and fine pattern is indispensable for miniaturization and high precision of hollow structure devices. However, with photosensitive polyimide resin, the range of materials that can be applied is small, and this requirement is sufficient. Difficult to answer.
In addition, since the photosensitive polyimide resin is difficult to form a thick film as described above, when the resin is applied as a material for forming a cover part having a hollow structure, it is difficult to form a cover part having a sufficient thickness and is thin. Since it is in the form of a film, it has poor durability under high temperature and high pressure conditions. Although it can be used in combination with a material having high rigidity as a reinforcing material, there arises a new problem that the cost and the number of production steps increase.

In addition, the photosensitive polyimide resin needs to be cured at 250 ° C. or higher in order to realize desired physical properties and characteristics. When heating at such a high temperature, it is difficult to apply to a SAW device or the like that may increase the stress generated or damage the substrate.
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.

Patent Documents 8 and 12 exemplify photosensitive acrylate resins other than photosensitive epoxy resins and photosensitive polyimide resins. It is well known that the physical properties and characteristics of the exemplified photosensitive acrylate resin change depending on the combination of various materials. However, as in the case of the above-described photosensitive epoxy resin and photosensitive polyimide resin, sufficient studies have not been made on the improvement of reliability such as prevention of deformation of the hollow structure and resistance to moist heat.
For this reason, the above-mentioned patent document does not specifically disclose the composition of the resin composition (resin type and structure, photopolymerization initiator, and other additives) that can simultaneously satisfy these characteristics. It is unclear and there is a demand for optimal material design.

  The present invention has been made in order to solve the above-described problems, and has excellent fine pattern formability, has a high elastic modulus at high temperature, has excellent heat and humidity resistance, and retains a hollow structure. A photosensitive resin composition, a photosensitive film using the photosensitive resin composition, a pattern forming method using the photosensitive resin composition or the photosensitive film, a method for forming a hollow structure, and an electronic component. The purpose is to provide.

In order to solve the above-mentioned problems, the inventors have improved the reliability, the high elastic modulus, and the composition of the photosensitive resin composition that can be applied as a forming material for the rib part and / or the cover part constituting the hollow structure. Thorough studies were conducted on thick film formation and pattern formation.
As a result, it has been found that a photosensitive resin composition containing a specific compound as a photopolymerization initiator together with a photopolymerizable compound having at least one ethylenically unsaturated group can solve the above problems, and to complete the present invention. It came.

That is, the present invention relates to the following [1] to [16].
[1] (A) a photopolymerizable compound having at least one ethylenically unsaturated group and (B) a photopolymerization initiator, and (B) an oxime ester compound and / or as a photopolymerization initiator A photosensitive resin composition comprising an acylphosphine oxide compound.
[2] The photopolymerization initiator (B) contains at least one of the compounds represented by the following formulas (1), (2), (3) and (4), as described in [1] above Photosensitive resin composition.

[In Formula (1), X ₁ and X ₂ each independently represent a hydrogen atom, a cyclic, linear or branched alkyl group having 1 to 12 carbon atoms, or an aryl group, and the alkyl group and The aryl group may be substituted with a substituent selected from the group consisting of a halogen atom, an alkoxy group having 1 to 6 carbon atoms, and an aryl group. X ₃ and X ₄ each independently represent a halogen atom, an alkyl group having 1 to 12 carbon atoms, a cyclopentyl group, a cyclohexyl group, a phenyl group, a benzyl group, a benzoyl group, an alkanoyl group having 2 to 12 carbon atoms, or 2 carbon atoms. -12 alkoxycarbonyl groups or a phenoxycarbonyl group is shown. p1 and p2 each independently represent an integer of 0 to 5. ]

Wherein (2), _{X 5} represents an alkanoyl group or a benzoyl group having 2 to 20 carbon atoms. X ₆ is an alkyl group having 1 to 12 carbon atoms, an alkanoyl group having 2 to 12 carbon atoms, an alkenoyl group having 4 to 6 carbon atoms in which a double bond is not conjugated with a carbonyl group, a benzoyl group, or 2 to 6 carbon atoms. An alkoxycarbonyl group or a phenoxycarbonyl group. X ₇ is a hydrogen atom, a halogen atom, an alkyl group having 1 to 12 carbon atoms, a cyclopentyl group, a phenyl group, a benzyl group, a benzoyl group, an alkanoyl group having 2 to 12 carbon atoms, an alkoxycarbonyl group having 2 to 12 carbon atoms, Or a phenoxycarbonyl group is shown. X ₈ , X ₉ and X ₁₀ are each independently a halogen atom, an alkyl group having 1 to 12 carbon atoms, a cyclopentyl group, a cyclohexyl group, a phenyl group, a benzyl group, a benzoyl group, an alkanoyl group having 2 to 12 carbon atoms, An alkoxycarbonyl group having 2 to 12 carbon atoms or a phenoxycarbonyl group is shown. p3, p4 and p5 each independently represent an integer of 0 to 5. ]

Wherein _{(3), R 1, R} 2 and _{R 3} each independently represent an alkyl group or aryl group having 1 to 20 carbon atoms. ]

[In formula (4), R ₄ , R ₅ and R ₆ each independently represents an alkyl group or aryl group having 1 to 20 carbon atoms. ]

[3] The photopolymerization initiator (B) contains at least one of the compounds represented by the following formulas (5), (6), (7) and (8), as described in [2] above Photosensitive resin composition.

Wherein _(5), X 2, _{X 3} and _{X 4,} the general formula (1) as synonymous. X ₁₁ is independently a halogen atom, an alkyl group having 1 to 12 carbon atoms, a cyclopentyl group, a cyclohexyl group, a phenyl group, a benzyl group, a benzoyl group, an alkanoyl group having 2 to 12 carbon atoms, or an alkyl group having 2 to 12 carbon atoms. An alkoxycarbonyl group or a phenoxycarbonyl group is shown. p1 and p2 are synonymous with the said General formula (1). p6 represents an integer of 0 to 5. ]

[In the formula (6), X ₆ , X ₇ , X ₈ , and X ₉ are as defined in the above formula (2). X ₁₂ is independently a halogen atom, an alkyl group having 1 to 12 carbon atoms, a cyclopentyl group, a cyclohexyl group, a phenyl group, a benzyl group, a benzoyl group, an alkanoyl group having 2 to 12 carbon atoms, or an alkyl group having 2 to 12 carbon atoms. An alkoxycarbonyl group or a phenoxycarbonyl group is shown. X ₁₃ represents a cyclic, linear or branched alkyl group having 1 to 12 carbon atoms, or a phenyl group. p3 and p4 are synonymous with the said General formula (2). p7 represents an integer of 0 to 5. ]

[In Formula (7), R < ₁₁ >, R < ₁₂ >, R < ₁₃ > shows a C1-C6 alkyl group or a C1-C4 alkoxy group each independently. m1, m2, and m3 each independently represent an integer of 0 to 5. When m1, m2, and m3 are 2 or more, a plurality of R ₁₁ , R ₁₂ , and R ₁₃ may be the same or different. ]

[In formula (8), R < ₁₄ >, R < ₁₅ >, R < ₁₆ > shows a C1-C6 alkyl group or a C1-C4 alkoxy group each independently. n1, n2, and n3 each independently represents an integer of 0 to 5. When n1, n2 and n3 are 2 or more, a plurality of R ₁₄ , R ₁₅ and R ₁₆ may be the same or different. ]

[4] The photosensitive resin composition according to any one of [1] to [3], wherein (A) the photopolymerizable compound contains at least an acrylate compound or a methacrylate compound having an amide group.
[5] The photosensitive resin composition according to any one of [1] to [3], wherein the (A) photopolymerizable compound contains a urethane compound having an acryloyl group or a methacryloyl group in at least one molecule. .
[6] The above [1] to [5], wherein the content of the (B) photopolymerization initiator is 0.3 to 10 parts by mass with respect to 100 parts by mass of the total solid content of the (A) photopolymerizable compound. ] The photosensitive resin composition in any one of.
[7] The photosensitive resin composition according to any one of [1] to [6], further including (C) a thermal polymerization initiator.
[8] The photosensitive resin composition according to any one of [1] to [7], further including (D) an inorganic filler.
[9] The photosensitive resin composition according to any one of [1] to [8], wherein the cured product of the photosensitive resin composition has an elastic modulus at 150 ° C. of 0.5 GPa or more.
[10] The photosensitive resin composition according to any one of [1] to [9], which is used as a material for forming one or both of a rib portion and a lid portion constituting the hollow structure in an electronic component having a hollow structure. object.
[11] A photosensitive film having a photosensitive resin layer comprising the photosensitive resin composition according to any one of [1] to [10].
[12] Lamination for forming a photosensitive resin layer by laminating the photosensitive resin composition according to any one of [1] to [10] or the photosensitive film according to [11] on a substrate. Removing a portion other than the exposed portion of the photosensitive resin layer by using a developer, an exposure step of irradiating a predetermined portion of the photosensitive resin layer with an actinic ray through a mask and photocuring the exposed portion The pattern formation method which has the image development process and the thermosetting process of thermosetting the said exposure part of the said photosensitive resin layer, and forming a resin cured material.
[13] A lamination process in which a rib pattern is provided to form a hollow structure on the substrate, and the photosensitive film having the photosensitive resin layer according to the above [11] is laminated on the rib pattern; A hollow having an exposure step of irradiating a predetermined portion of the resin layer with actinic rays to photo-cure the exposed portion, and a thermosetting step of thermosetting the exposed portion of the photosensitive resin layer to form a resin cured product Structure formation method.
[14] The method for forming a hollow structure according to [13], wherein the rib pattern is formed by the pattern forming method according to [12].
[15] A hollow structure rib and / or lid is formed using the photosensitive resin composition according to any one of [1] to [10] or the photosensitive film according to [11]. An electronic component having a hollow structure.
[16] The electronic component according to [15], wherein the electronic component is a surface acoustic wave filter.

  Since the photosensitive resin composition of the present invention has excellent photocurability and optical resolution, not only can a fine pattern be formed with a thick film, but the cured product of the resin composition has a high elastic modulus at high temperatures. In addition, high adhesion to the substrate can be expressed. Therefore, the electronic device having a hollow structure to which the photosensitive resin composition of the present invention is applied has a high elastic modulus at high temperature, rigidity and heat-and-moisture resistance, and is excellent in retention of the hollow structure. In addition, the improvement in photocurability contributes to the high heat resistance of the cured resin and the high adhesion to the substrate, so it can improve the reflow crack resistance in thick films and has excellent moisture and heat resistance. For example, high adhesiveness is maintained even in a severe high temperature and high humidity atmosphere such as a PCT (pressure cooker) test, and the reliability of the hollow structure device can be ensured.

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 the manufacturing method of the SAW filter by which the metal ball | bowl of this invention is mounted. It is a figure which shows the wiring formation method of the SAW filter which has a 2 layer wiring layer which is one of the electronic components of this invention. 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. It is a figure which shows the evaluation criteria of the resolution about the photosensitive resin composition 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.
Further, in the following description of the present specification, for example, the notation “(meth) acrylate compound” is a term meaning one or both of “acrylate compound” and “methacrylate compound”, “(meth) acryloyl group” The term “” is used as a term meaning one or both of “acryloyl group” and “methacryloyl group”. The same applies to other similar terms.
Furthermore, in this specification, a rib part means the frame which can comprise the side surrounding wall of a hollow structure. The frame body is not particularly limited as long as it is a shape that can constitute the side wall of the hollow structure, and the outer shape in plan view may be a triangle, a quadrangle, or a pentagon or more polygon, such as a perfect circle, an ellipse, etc. It may be a circular shape. The frame may be a frame that is partially missing. Examples of the frame that is partially missing include a U-shaped shape, an alphabetic C-shaped shape, and the like. The rib pattern refers to a rib pattern formed by photolithography.

  The photosensitive resin used as the material for the ribs and lids of the hollow structure is formed by patterning by light exposure, so that it is excellent in light transmission and fine patterning properties even with thick films, and for improving heat and humidity resistance. It is preferable that the cured product has high heat resistance and low moisture absorption and low moisture permeability. As described above, it is difficult to meet this requirement with a photosensitive epoxy resin or a photosensitive polyimide resin that has been conventionally used in lithography technology.

  First, the present inventors have (A) a photopolymerizable compound having at least one ethylenic unsaturation (hereinafter also referred to as “(A) component” or “(A) photopolymerizable compound”). Focusing on the high reactivity, (A) the photosensitive resin composition containing the photopolymerizable compound is not only excellent in the photosensitive properties of thick film formation and fine pattern formation, but also the heat resistance of the cured resin. It was found that it can be improved.

  Specifically, by using the photopolymerizable compound (A), it becomes easy to improve the glass transition temperature and reduce the moisture absorption rate. Moreover, since the selection range becomes wide as a low-viscosity material, it is easy to arbitrarily adjust the viscosity of the photosensitive resin composition applied on the substrate when forming the rib portion or the lid portion. Although it is possible to lower the viscosity of the photosensitive resin composition to be applied using a solvent, at least using this (A) photopolymerizable compound has an adverse effect on the properties and reliability of the cured product of the resin composition. The amount of solvent applied can be reduced. In addition, even when the photosensitive resin composition contains a large amount of an inorganic filler or the like, the applicability and film formability of the resulting photosensitive resin composition can be maintained.

However, the photosensitive resin composition used as a material for forming the rib portion and the lid portion of the hollow structure is more photocurable than the conventional ones from the viewpoints of thick film formation, retention of the hollow structure, and high reliability. Characteristics that can significantly improve the optical resolution are required.
In contrast, the present inventors include (A) a photopolymerizable compound and (B) a photopolymerization initiator, and (B) a oxime ester compound and / or an acylphosphine oxide compound as a component. It has been found that a photosensitive resin composition containing the above solves the above problem.

The photosensitive resin composition of the present invention has a thick film forming property and fineness by applying a specific compound as a photopolymerization initiator (B) in order to improve the photocurability and optical resolution of the component (A). For example, when used as a material for forming hollow structure ribs and lids with improved patternability, it is possible to improve the properties of the cured resin and achieve both hollow structure retention and reliability. .
Therefore, the photosensitive resin composition of the present invention can be suitably used as a material for forming one or both of the rib portion and the lid portion constituting the hollow structure in an electronic component having a hollow structure. Hereinafter, the photosensitive resin composition of the present invention will be described.

[Photosensitive resin composition]
The photosensitive resin composition of the present invention contains (A) a photopolymerizable compound having at least one ethylenically unsaturated group and (B) a photopolymerization initiator. In the photosensitive resin composition, (B) an oxime ester compound and / or an acylphosphine oxide compound is included as a photopolymerization initiator.
The photosensitive resin composition of the present invention preferably further comprises (C) a thermal polymerization initiator and (D) an inorganic filler, and further comprises (E) a sensitizer, (F) a heat resistant polymer, (G ) Other components such as a thermal crosslinking agent, (H) a thermal acid generator, and an adhesion aid can be blended.
Hereinafter, each component contained in the photosensitive resin composition of the present invention will be described.

<(A) Photopolymerizable compound having at least one ethylenically unsaturated group>
The photosensitive resin composition of this invention contains the photopolymerizable compound ((A) photopolymerizable compound) which has at least 1 ethylenically unsaturated group as (A) component.
(A) As a photopolymerizable compound, for example, a compound obtained by reacting a polyhydric alcohol with an α, β-unsaturated carboxylic acid, a (meth) acrylate compound having an amide bond, or a urethane having a (meth) acryloyl group Compounds obtained by reacting α-, β-unsaturated carboxylic acids with bisphenol A (meth) acrylate compounds, glycidyl group-containing compounds, and (meth) acrylic acid alkyl ester copolymers. Examples thereof include a compound into which a saturated group has been introduced.
These (A) photopolymerizable compounds may be used alone or in combination of two or more.

  Among these, a (meth) acrylate compound having an amide group is preferable from the viewpoint of enhancing the adhesion to the substrate, maintaining the adhesion at high temperature, improving the reflow crack resistance, and improving the resolution. .

  Moreover, since photopolymerization reactivity is high, the viewpoint which can improve thick film formation property and pattern formation property, and the viewpoint which can make high heat resistance and high adhesiveness of the hardened | cured material of the obtained photosensitive resin composition compatible. Therefore, urethane compounds having a (meth) acryloyl group are preferred.

A photosensitive resin composition using a (meth) acrylate compound having an amide group and / or a urethane-based compound having a (meth) acryloyl group can be applied to an electronic component having a hollow structure, for example. Can greatly improve the performance.
From the above viewpoint, the component (A) preferably includes a (meth) acrylate compound having an amide group and / or a urethane compound having a (meth) acryloyl group, and the (meth) acrylate compound having an amide group and ( More preferably, a urethane compound having a (meth) acryloyl group is used in combination.

  In the photosensitive resin composition of the present invention, the content of the (meth) acrylate compound having an amide group is preferably 30% by mass or more based on the total amount of the component (A) from the viewpoint of improving the resolution. Furthermore, it is preferably 35% by mass or more, more preferably 50% by mass or more, from the viewpoint of improving adhesion.

  In the photosensitive resin composition of the present invention, the content of the urethane-based compound having a (meth) acryloyl group is the total amount of the component (A) from the viewpoints of applicability, thick film formation, and pattern formation. On the other hand, it is preferably 50% by mass or more, more preferably 55% by mass or more, and further preferably 65% by mass or more.

  In the photosensitive resin composition of the present invention, as the component (A), when the (meth) acrylate compound having the amide group and the urethane compound having the (meth) acryloyl group are used in combination, The combined content is preferably 50% by mass or more, more preferably 65% by mass or more, still more preferably 80% by mass or more, and still more preferably 90% by mass or more, based on the total amount of component (A). . When the content is 50% by mass or more, it is possible to obtain a photosensitive resin composition that not only has excellent photosensitive characteristics but also can simultaneously realize hollow structure retention and improved reliability.

  In the photosensitive resin composition of the present invention, when the (meth) acrylate compound having the amide group and the urethane compound having the (meth) acryloyl group are used in combination as the component (A), an amide The content ratio of the (meth) acrylate compound having a group and the urethane compound having a (meth) acryloyl group [(meth) acrylate compound / urethane compound having an amide group] (mass ratio) is preferably 20/80 to 70. / 30, more preferably 30/70 to 60/40, still more preferably 32/68 to 50/50.

((Meth) acrylate compound having amide bond)
The (meth) acrylate compound having an amide bond is preferably a compound represented by the following general formula (9) from the viewpoint of resolution and adhesiveness.

In the above formula (9), R ₃₁ , R ₃₂ and R ₃₃ each independently represent a divalent organic group, R ₃₄ represents a hydrogen atom or a methyl group, and R ₃₅ and R ₃₆ each independently , A hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or a phenyl group.
Examples of the divalent organic group include a phenylene group, a pyridylene group, a linear or branched alkylene group having 1 to 10 carbon atoms, and an alicyclic structure-containing group having 1 to 10 carbon atoms. In addition, these groups may be substituted with a substituent such as a halogen atom, an alkoxy group having 1 to 6 carbon atoms, and an aryl group.

  The compound represented by the general formula (9) is a di (meth) acrylate having an amide bond, obtained by reacting an oxazoline group-containing compound with a carboxy group-containing compound and / or a phenolic hydroxyl group-containing compound. It is preferable. By using this compound, it becomes easy to obtain a cured resin having high elasticity and high heat resistance.

  The compound represented by the general formula (9) includes, for example, a bisoxazoline represented by the following general formula (10), a compound having two phenolic hydroxyl groups in one molecule, (meth) acrylic acid, Can be obtained by reacting.

In General Formula (10), Y ⁴ represents a divalent organic group, but may have a phenylene group that may have a substituent, a pyridylene group that may have a substituent, or a substituent. It is preferably a linear or branched alkylene group having 1 to 10 carbon atoms, or an alicyclic structure-containing group having 1 to 10 carbon atoms which may have a substituent, from the viewpoint of improving heat resistance, A phenylene group which may have a substituent and a pyridylene group which may have a substituent are more preferable. From the viewpoint of improving moisture resistance, a straight chain having 1 to 10 carbon atoms which may have a substituent. A chain or branched alkylene group and an alicyclic structure-containing group having 1 to 10 carbon atoms which may have a substituent are more preferable.
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 (10) 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 compounds 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-dichloropheny) ) Hexafluoropropane, bis (4-hydroxyphenyl) dimethylsilane, bis (4-hydroxy-3,5-dimethylphenyl) dimethylsilane, bis (4-hydroxy-3,5-dichlorophenyl) dimethylsilane, bis (4- Hydroxyphenyl) 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-hydride) Xylphenyl) 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) Ci-3,5-dibromophenyl) fluorene and the like.
Among these, 2,2-bis (4-hydroxy-3,5-dichlorophenyl) propane is preferable.
In addition, these compounds can be used individually or in combination of 2 or more types.

The reaction of the oxazoline group-containing compound with the carboxy group-containing compound and / or the phenolic hydroxyl group-containing compound is preferably performed at a reaction temperature of 50 to 200 ° C.
If reaction temperature is 50 degreeC or more, reaction can be advanced efficiently. On the other hand, if the reaction temperature is 200 ° C. or lower, side reactions can be sufficiently suppressed.
Moreover, in the said reaction, you may react in polar organic solvents, such as a dimethylformamide, a dimethylacetamide, and a dimethylsulfoxide, as needed.

(Urethane compound having (meth) acryloyl group)
Examples of the urethane compound having the (meth) acryloyl group include an OH group at the β-position such as 2-hydroxyethyl (meth) acrylate, dipentaerythritol penta (meth) acrylate, pentaerythritol tri (meth) acrylate, and the like. Addition reaction product of (meth) acrylic monomer and diisocyanate compound such as isophorone diisocyanate, 2,6-toluene diisocyanate, 2,4-toluene diisocyanate, 1,6-hexamethylene diisocyanate; EO-modified urethane di (meth) acrylate; EO Or PO-modified urethane di (meth) acrylate; carboxyl group-containing urethane (meth) acrylate; diol compound, bifunctional epoxy (meth) acrylate and polyisocyanate reaction product.

The number of (meth) acryloyl groups that are functional groups in one molecule of the urethane compound having the (meth) acryloyl group is preferably 2 to 2 from the viewpoints of heat resistance, adhesion, coatability, and pattern formability. There are 15 pieces.
If the number of the (meth) acryloyl groups is 2 or more, the heat resistance of the cured product obtained from the resin composition can be improved and the rigidity can be increased. On the other hand, if it is 15 or less, it is possible to achieve both high adhesiveness and reliability is improved.
Moreover, if the number of (meth) acryloyl groups is 2 to 15, the weight average molecular weight can be optimized and the viscosity of the urethane compound can be adjusted to be low, so that the photosensitive resin composition can be easily applied. In addition, when the photosensitive resin composition after application is irradiated with light, the phenomenon that only the surface portion is rapidly photocured can be suppressed, so the resolution is lowered and the pattern formability is lowered. The phenomenon of doing can be suppressed. Furthermore, the problem that an unreacted (meth) acryloyl group tends to remain even after photocuring and / or heat curing does not occur, and fluctuations in physical properties and characteristics of the resin can be suppressed.

  The number of the (meth) acryloyl groups is preferably 2 to 15 from the above viewpoint, but it is possible to improve the applicability and resolution and to stabilize the physical properties and characteristics of the cured product after photocuring. More preferably 2 to 12, and still more preferably 2 to 10.

The urethane compound preferably has a weight average molecular weight (Mw) of 950 to 25000. In addition, the said weight average molecular weight means the value measured using the tetrahydrofuran as a developing solvent by the gel permeation chromatograph (GPC) method.
When the weight average molecular weight is 950 or more, the viscosity of the obtained resin composition does not become too low, and when applied on a substrate, dripping of the applied resin composition can be suppressed, thereby improving applicability. Can be made. Further, since the volumetric shrinkage of the urethane compound can be reduced during photocuring, the formation of a thick film is facilitated, and the stress of the resin due to the shrinkage by curing is reduced, thereby improving the reliability.
On the other hand, if the said weight average molecular weight is 25000 or less, the viscosity of the obtained photosensitive resin composition will not become high too much, while it can make applicability | paintability favorable and a thick film formation property also improves. Moreover, since it is the weight average molecular weight adjusted so that the approach of functional groups may become easy during photopolymerization reaction, photocurability becomes high and thick film formation property and pattern formation property improve.

  The weight average molecular weight of the urethane compound is preferably 950 to 25000. From the viewpoint of further improving the coating properties and resolution, and further stabilizing the physical properties and characteristics of the photosensitive resin composition after photocuring. Preferably it is 950-15000, More preferably, it is 950-12000.

Examples of commercially available urethane compounds having an acryloyl group include UN-904 (functional group number: 10, Mw: 4900), UN-952 (functional group number: 10, Mw: 6500 to 11000), UN-333 (functional). Number of groups: 2, Mw: 5000), UN-1255 (number of functional groups: 2, Mw: 8000), UN-2600 (number of functional groups: 2, Mw: 2500), UN-6200 (number of functional groups: 2, Mw: 6500) UN-3320HA (functional group number: 6, Mw: 1500), UN-3320HC (functional group number: 6, Mw: 1500), UN-9000PEP (functional group number: 2, Mw: 5000), UN-9200A (functional group number: 2, Mw: 15000), UN-3320HS (functional group number: 15, Mw: 4900), UN-6301 (functional group number: 2, Mw: 33) 00) (all are trade names, manufactured by Negami Kogyo Co., Ltd.), TMCH-5R (trade names, manufactured by Hitachi Chemical Co., Ltd.), KRM8452 (functional group number = 10, Mw = 1200), EBECRYL 8405 (urethane acrylate / 1, 6-hexanediol diacrylate = 80/20 addition reaction product, number of functional groups = 4, Mw = 2700) (all of these are trade names, manufactured by Daicel Cytec Co., Ltd.) and the like.
Examples of urethane compounds having a methacryloyl group include UN-6060PTM (functional group number: 2, Mw: 6000, trade name, manufactured by Negami Kogyo Co., Ltd.), JTX-0309 (trade name, manufactured by Hitachi Chemical Co., Ltd.), UA. -21 (trade name, manufactured by Shin-Nakamura Chemical Co., Ltd.).

(Compound obtained by reacting polyhydric alcohol with α, β-unsaturated carboxylic acid)
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 compounds may be used alone or in combination of two or more.

(Bisphenol A-based (meth) acrylate compound)
Examples of bisphenol A-based (meth) acrylate compounds include 2,2-bis (4-((meth) acryloxypolyethoxy) phenyl) propane and 2,2-bis (4-((meth) acryloxypolypropoxy). ) Phenyl) propane, 2,2-bis (4-((meth) acryloxypolybutoxy) phenyl) propane, 2,2-bis (4-((meth) acryloxypolyethoxypolypropoxy) phenyl) propane, etc. Can be mentioned.
These compounds can be used alone or in combination of two or more.

(A compound obtained by reacting a glycidyl group-containing compound with an α, β-unsaturated carboxylic acid)
Examples of the compound obtained by reacting the glycidyl group-containing compound with an α, β-unsaturated carboxylic acid include, for example, epoxy resins such as novolak type epoxy resins, bisphenol type epoxy resins, salicylaldehyde type epoxy resins, and (meth) Examples include epoxy (meth) acrylate compounds obtained by reacting acrylic acid. An acid-modified epoxy acrylate compound obtained by reacting an acid anhydride such as tetrahydrophthalic acid anhydride with the OH group of the epoxy (meth) 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 (11) is commercially available.

[In the formula (11), the ratio of m to n is 100/0 to 0/100. ]

(Compound with an ethylenically unsaturated group introduced to the copolymer of alkyl (meth) acrylate)
Examples of the compound in which an ethylenically unsaturated group is introduced to the copolymer of (meth) acrylic acid alkyl ester include (meth) acrylic acid methyl ester, (meth) acrylic acid ethyl ester, (meth) acrylic acid. Examples thereof include compounds in which an ethylenically unsaturated group such as a (meth) acryloyl group is introduced into a copolymer such as butyl ester and (meth) acrylic acid 2-ethylhexyl ester.
These compounds can be used alone or in combination of two or more.

<(B) Photopolymerization initiator>
In the photosensitive resin composition of the present invention, as a photopolymerization initiator (B) contained together with the component (A), free radicals are generated by actinic rays. Particularly, photocurability is improved and sensitivity is increased. From the viewpoint of high resolution, an oxime ester compound and / or an acylphosphine oxide is included.
The photosensitive resin composition of the present invention can improve photocurability by containing an oxime ester compound and / or acylphosphine oxide as a photopolymerization initiator (B), and can have a rib part and / or a lid. When applied as a material for forming the part, the hollow structure retainability can be improved.

(Oxime ester compounds)
In the photosensitive resin composition of the present invention, as the oxime ester compound contained as the component (B), photocurability is improved, and the resulting photosensitive resin composition is used as a rib and / or lid forming material. From the viewpoint of exhibiting excellent hollow structure retainability when applied to the compound, a compound represented by the following general formula (1) or the following general formula (2) is preferable.

In the above formula (1), X ₁ and X ₂ each independently represent a hydrogen atom, a cyclic, linear or branched alkyl group having 1 to 12 carbon atoms, or an aryl group, and the alkyl group and The aryl group may be substituted with a substituent selected from the group consisting of a halogen atom, an alkoxy group having 1 to 6 carbon atoms, and an aryl group.
X ₃ and X ₄ each independently represent a halogen atom, an alkyl group having 1 to 12 carbon atoms, a cyclopentyl group, a cyclohexyl group, a phenyl group, a benzyl group, a benzoyl group, an alkanoyl group having 2 to 12 carbon atoms, or 2 carbon atoms. -12 alkoxycarbonyl groups or a phenoxycarbonyl group is shown.
p1 and p2 each independently represent an integer of 0 to 5.

In the above formula (2), _{X 5} represents an alkanoyl group or a benzoyl group having 2 to 20 carbon atoms.
X ₆ is an alkyl group having 1 to 12 carbon atoms, an alkanoyl group having 2 to 12 carbon atoms, an alkenoyl group having 4 to 6 carbon atoms in which a double bond is not conjugated with a carbonyl group, a benzoyl group, or 2 to 6 carbon atoms. An alkoxycarbonyl group or a phenoxycarbonyl group.
X ₇ is a hydrogen atom, a halogen atom, an alkyl group having 1 to 12 carbon atoms, a cyclopentyl group, a phenyl group, a benzyl group, a benzoyl group, an alkanoyl group having 2 to 12 carbon atoms, an alkoxycarbonyl group having 2 to 12 carbon atoms, Or a phenoxycarbonyl group is shown.
X ₈ , X ₉ and X ₁₀ are each independently a halogen atom, an alkyl group having 1 to 12 carbon atoms, a cyclopentyl group, a cyclohexyl group, a phenyl group, a benzyl group, a benzoyl group, an alkanoyl group having 2 to 12 carbon atoms, An alkoxycarbonyl group having 2 to 12 carbon atoms or a phenoxycarbonyl group is shown.
p3, p4 and p5 each independently represent an integer of 0 to 5.

  Among the compounds represented by the general formula (1), a compound represented by the following general formula (5) is more preferable from the viewpoints of improvement of photocurability, high sensitivity, and high resolution.

In the above formula _(5), X 2, _{X 3} and _{X 4} have the same meanings as in general formula (1).
X ₁₁ is independently a halogen atom, an alkyl group having 1 to 12 carbon atoms, a cyclopentyl group, a cyclohexyl group, a phenyl group, a benzyl group, a benzoyl group, an alkanoyl group having 2 to 12 carbon atoms, or an alkyl group having 2 to 12 carbon atoms. An alkoxycarbonyl group or a phenoxycarbonyl group is shown.
p1 and p2 are synonymous with the said General formula (1), and p6 shows the integer of 0-5.

  As a commercial item of the compound represented by the general formula (5), for example, 1,2-octanedione-1- [4- (phenylthio) phenyl] -2- (O-benzoyloxime) (trade name: IRGACURE) -OXE-01, manufactured by BASF).

  Moreover, among the compounds represented by the general formula (2), the compounds represented by the following general formula (6) are more preferable from the viewpoints of improvement of photocurability, high sensitivity, and high resolution.

In the above formula _{(6), X 6, X} 7, X 8, and _{X 9} have the same meanings as in general formula (2).
X ₁₂ is independently a halogen atom, an alkyl group having 1 to 12 carbon atoms, a cyclopentyl group, a cyclohexyl group, a phenyl group, a benzyl group, a benzoyl group, an alkanoyl group having 2 to 12 carbon atoms, or an alkyl group having 2 to 12 carbon atoms. An alkoxycarbonyl group or a phenoxycarbonyl group is shown.
X ₁₃ represents a cyclic, linear or branched alkyl group having 1 to 12 carbon atoms, or a phenyl group.
p3 and p4 are synonymous with the said General formula (2). p7 represents an integer of 0 to 5.

  As a commercial item of the compound represented by the general formula (6), for example, 1- [9-ethyl-6- (2-methylbenzoyl) -9H-carbazol-3-yl] ethanone 1- (O-acetyl) Oxime) (trade name: IRGACURE-OXE-02, manufactured by BASF) and the like.

  As an oxime ester compound, in addition to the above-mentioned compounds, 1-phenyl-1,2-propanedione-2- [O- (ethoxycarbonyl) oxime] (trade name: Quantacure-PDO, manufactured by Nippon Kayaku Co., Ltd.) ) And the like.

(Acylphosphine oxide compounds)
In the photosensitive resin composition of the present invention, as the acylphosphine oxide compound contained as component (B), photocurability is improved, and the resulting photosensitive resin composition is formed into a rib part and / or a lid part. A compound represented by the following general formula (3) or the following general formula (4) is preferable from the viewpoint of developing excellent hollow structure retention when applied to a material.

In the formula _{(3), R 1, R} 2 and _{R 3} each independently represent an alkyl group or aryl group having 1 to 20 carbon atoms.

In said formula (4), R < ₄ >, R < ₅ > and R < ₆ > show a C1-C20 alkyl group or aryl group each independently.

  Among the compounds represented by the general formula (3), a compound represented by the following general formula (7) is more preferable from the viewpoints of improvement of photocurability, high sensitivity, and high resolution.

In said formula (7), R < ₁₁ >, R <_12> , R < ₁₃ > shows a C1-C6 alkyl group or a C1-C4 alkoxy group each independently.
m1, m2, and m3 each independently represent an integer of 0 to 5.
When m1, m2 and m3 are 2 or more, a plurality of R ₁₁ , R ₁₂ and R ₁₃ may be the same or different.

  Examples of commercially available compounds represented by the general formula (7) include 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide (trade name: DAROCURE-TPO, manufactured by BASF).

  Further, among the compounds represented by the general formula (4), the compounds represented by the following general formula (8) are more preferable from the viewpoints of improvement of photocurability, high sensitivity, and high resolution.

In said formula (8), R <_14> , R <_15> , R < ₁₆ > shows a C1-C6 alkyl group or a C1-C4 alkoxy group each independently.
n1, n2, and n3 each independently represents an integer of 0 to 5.
When n1, n2 and n3 are 2 or more, a plurality of R ₁₄ , R ₁₅ and R ₁₆ may be the same or different.

  Examples of commercially available compounds represented by the general formula (8) include bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide (trade name: IRGACURE-819, manufactured by BASF). .

In addition, these compounds can be used individually or in combination of 2 or more types.
Among the above compounds, the compound represented by the general formula (1) or the general formula (4) is more preferable from the viewpoint of exhibiting comprehensively excellent physical properties and characteristics in the production and reliability of the hollow structure device. A compound represented by the formula (5) or the general formula (8) is more preferable, and a commercially available product is 1,2-octanedione-1- [4- (phenylthio) phenyl] -2- (O-benzoyloxime). (Trade name: OXE-01, manufactured by Ciba Specialty Chemicals) and bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide (trade name: IRGACURE-819, manufactured by Ciba Specialty Chemicals) are preferable.

(B) Since the content of the photopolymerization initiator is determined according to the amount of exposure at the time of pattern formation, generally the amount may be smaller when the amount of exposure is large, and is larger when the amount of exposure is small. May be.
However, the content of the photopolymerization initiator (B) in the photosensitive resin composition of the present invention is preferably 0.3 to 10 parts by mass with respect to 100 parts by mass of the total solid content of the photopolymerizable compound (A). More preferably, it is 0.5-5 mass parts, More preferably, it is 0.5-3 mass parts.
If content of (B) component is 0.3 mass part or more, photocurability of the grade which can form a pattern will be obtained, and hollow structure retainability can be improved. Further, pattern swelling during development can be suppressed, and a reduction in resolution can also be suppressed. On the other hand, if the content of the component (B) is 10 parts by mass or less, not only the photocuring at the surface portion of the photosensitive resin composition after application to the substrate is promoted, but also the light inside the resin composition. Curing is also promoted, and it becomes easy to form a cured film having a uniform cured state, and the effects of suppressing a decrease in resolution and suppressing the generation of outgas are remarkably exhibited.

  In addition, content of (B) photoinitiator in the case of using an oxime ester type compound as (B) component is a hollow structure retainability with respect to 100 mass parts of solid content of (A) photopolymerizable compound. From the viewpoint of improving the resolution, it is more preferably 0.5 to 2 parts by mass, and from the viewpoint of improving the resolution, still more preferably 0.8 to 1.5 parts by mass.

  On the other hand, when an acylphosphine oxide compound is used as the component (B), the content of the photopolymerization initiator (B) is maintained as a hollow structure with respect to 100 parts by mass of the total solid content of the photopolymerizable compound (A). From the viewpoint of improving the property, it is more preferably 1 to 3 parts by mass, and from the viewpoint of improving the resolution, it is further preferably 1 to 2 parts by mass.

The photosensitive resin composition of the present invention may contain a photopolymerizable compound other than the oxime ester compound and the acylphosphine oxide compound as the photopolymerizable compound (B) as long as the effects of the present invention are not impaired. Good.
The total content of the oxime ester compound and the acylphosphine oxide compound in the photopolymerizable compound (B) in the photosensitive resin composition of the present invention is preferably 80 to 100 with respect to the total amount of the component (B). % By mass, more preferably 90 to 100% by mass, still more preferably 95 to 100% by mass, and still more preferably substantially 100% by mass.

<(C) Thermal polymerization initiator>
In the case of forming a hollow structure using the photosensitive resin composition of the present invention, after applying the resin composition to the substrate, the coated film is exposed to light using a pattern mask and developed, and then exposed to light. A hollow structure is formed through a thermosetting step in which the resin is cured by heat to form a cured resin. At that time, since the physical properties and characteristics of the cured resin have a great influence on the retention of the hollow structure and the reliability of the electronic component, it is preferable to proceed the curing by polymerization of the photosensitive resin composition as much as possible.
In the photosensitive resin composition of this invention, even if it does not contain a thermal polymerization initiator, the characteristic excellent in the thick film formation property at the time of light exposure and pattern formation property is shown.
However, in order to maintain desired hollow structure retention and reliability, the photosensitive resin of the present invention is used from the viewpoint of forming a resin composition that can withstand higher temperature heating and long-time heating in the thermosetting step. It is preferable that the composition further contains (C) a thermal polymerization initiator.

Although there is no restriction | limiting in particular as (C) thermal-polymerization initiator contained in the photosensitive resin composition of this invention, A thermal radical generator is preferable.
Examples of the thermal radical generator include t-butylcumyl peroxide (commercially available product: perbutyl C (trade name, manufactured by NOF Corporation)), n-butyl 4,4-di- (t-butylperoxy) valerate. Examples include organic peroxides such as (commercially available product: Perhexa V (trade name, manufactured by NOF Corporation)) and dicumyl peroxide (commercial product: Park Mill D (trade name, manufactured by NOF Corporation)).

  The blending amount of the thermal polymerization initiator is preferably 0.1 to 30 parts by mass, more preferably 0.2 to 20 parts by mass, and still more preferably 0.00 with respect to 100 parts by mass of the total solid content of the component (A). 5 to 10 parts by mass.

<(D) Inorganic filler>
The photosensitive resin composition of the present invention can further contain (D) an inorganic filler.
Examples of the (D) inorganic filler include silica, alumina, titanium oxide, zirconia, ceramic fine powder, talc, mica, boron nitride, kaolin, and barium sulfate.
The volume average particle size of the inorganic filler is preferably 10 nm to 50 μm.
If the said particle size is 10 nm or more, aggregation of the inorganic filler in the photosensitive resin composition can be prevented, uniform dispersion | distribution will be attained, and fine pattern formation property can be improved. In addition, variations in physical properties and characteristics of the cured product can be reduced. On the other hand, if the particle size is 50 μm or less, the scattering of irradiation light by the inorganic filler can be suppressed, so that thick film formability and fine pattern formability are improved.
The volume average particle diameter of the inorganic filler here can be determined as a MV value (Mean Volume Diameter: volume average value) by a laser diffraction particle size distribution meter (for example, Nikkiso Co., Ltd., trade name: Microtrack MT3000). .

As the shape of the inorganic filler, any of a spherical shape, a crushed shape, a needle shape, and a plate shape can be used, and a desired shape can be selected according to the particle diameter. For example, an inorganic filler with a small particle diameter having a volume average particle diameter in the range of 10 nm to 1 μm and having a spherical or nearly spherical shape not only increases the elastic modulus of the photosensitive resin composition at high temperatures, but also a cured product machine. In addition, it can improve the coating strength by imparting thixotropy to the photosensitive resin composition before curing. Therefore, it is preferable that the inorganic filler having a small particle diameter is used when it is desired to slightly improve the physical properties and characteristics of the photosensitive resin composition of the present invention without adversely affecting the light transmittance and light absorption.
Moreover, since the inorganic filler having a large particle diameter in the range of 1 μm to 50 μm can greatly increase the elastic modulus of the photosensitive resin composition at a high temperature, the shape maintaining property of the hollow structure can be improved. Demonstrate great effect. Furthermore, the inorganic filler having a plate shape as the shape can greatly reduce the moisture absorption rate and moisture permeability of the cured product of the photosensitive resin composition. Thus, when applying as a forming material of a rib part or a cover part of a hollow structure, in the photosensitive resin composition of this invention, it is preferable to contain the inorganic filler of the large particle diameter which has plate shape as a shape.

The average aspect ratio of the inorganic filler is preferably 30 to 100, and more preferably 40 to 40, from the viewpoint of improving the retention of the hollow part under high temperature and high pressure and obtaining a highly reliable photosensitive resin composition having heat and moisture resistance. 90, more preferably 50-80.
In this invention, if the average aspect-ratio of an inorganic filler is 30 or more, it exists in the tendency for the moisture absorption to a photosensitive resin and the reduction effect of moisture permeation to become easy to be expressed. In addition, an effect of increasing the elastic modulus is also obtained, and for example, a hollow part retaining property that can withstand a sealing resin mold pressure at a high temperature can be obtained. On the other hand, if the average aspect ratio is 100 or less, the photosensitive properties such as thick film formability and fine pattern formability are good.

  The volume average particle diameter of the inorganic filler is preferably 10 nm to 50 μm. From the viewpoint of improving the hollow part retention under high temperature and high pressure, and obtaining a highly reliable photosensitive resin composition having moisture and heat resistance. Preferably it is 5-50 micrometers, More preferably, it is 8-40 micrometers, More preferably, it is 10-30 micrometers. If the volume average particle diameter of the inorganic filler is 5 μm or more, the effect of reducing moisture absorption or moisture permeation to the photosensitive resin tends to be expressed. In addition, an effect of increasing the elastic modulus can be obtained.

By using an inorganic filler having such an aspect ratio and volume average particle size, the resulting photosensitive resin composition can exhibit low hygroscopicity, moisture permeability and excellent rigidity, for example, high temperature It is possible to obtain a hollow portion retainability that can withstand the sealing resin mold pressure at the above.
In addition, when an inorganic filler is contained in the photosensitive resin composition, the thick film formability and the fine pattern formability generally tend to decrease, but the shape, aspect ratio, and volume average particle size of the inorganic filler are reduced. By using an inorganic filler belonging to the above range, 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. The shape of the inorganic filler is preferably a plate shape (including a flat plate shape, a disk shape, a flat shape, and a scale shape), and in the present invention, a scale shape is more preferable.

The aspect ratio of the inorganic filler can be determined using a scanning electron microscope or a transmission 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 smooth). An image is captured (photographed) from the direction of a wide surface, for example, the cleaved surface (X surface) of 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 mica, etc. An image is taken in (taken) from the direction of (fracture surface); From the image (photograph) thus obtained, first, for the particle image of the X plane, 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, two parallel lines are closest to each other and the distance between the parallel lines drawn so as to sandwich the particle 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.
The inorganic filler can be measured and analyzed by dispersing it in water using phosphinates as a dispersant.

  In the present invention, as the component (D), the average aspect ratio is 30 to 100 (preferably 40 to 90, more preferably 50 to 80), and the volume average particle size is 5 to 50 μm (preferably 8 to 40 μm, More preferably, an inorganic filler of 10 to 30 μm) is used. By using such an inorganic filler, it is possible to achieve both of the photosensitive characteristics such as the thick film formability and the fine pattern formability, and the moist heat resistance and high elastic modulus of the cured resin.

Examples of the inorganic filler having an average aspect ratio of 30 to 100 and a volume average particle diameter of 5 to 50 μm include talc, mica, boron nitride, kaolin, and barium sulfate. Among these, mica is preferable.
Mica has a relatively large average aspect ratio, many satisfy the above range, and has high shape uniformity. For this reason, the moisture permeability to the photosensitive resin composition is reduced, and not only the mold resistance is increased by increasing the elastic modulus, but also the effect of suppressing the deterioration of the photosensitive characteristics as compared with other inorganic fillers.
In addition, the inorganic filler to be used is preferably a synthetic material and more preferably synthetic mica from the viewpoint that the impurities contained are small. When there are few impurities contained in an inorganic filler, since the inhibition with respect to photocurability can be made small and a moisture-resistant fall can be suppressed, the reliability of a hollow structure device can be improved significantly.

In the present invention, as the inorganic filler (D), a commercially available product can be used, and a plurality of commercially available products may be mixed or processed.
For example, commercially available products of mica include, for example, A-51S (average aspect ratio 85, volume average particle size 52 μm), SYA-31RS (average aspect ratio 90, volume average particle size 40 μm), SYA-21RS (average aspect ratio). 90, volume average particle size 27 μm), SJ-005 (average aspect ratio 30, volume average particle size 5 μm) and other mica manufactured by Yamaguchi Mica Industry Co., Ltd.

  The content of the (D) inorganic filler in the photosensitive resin composition of the present invention is preferably 0.5 to 60% by mass, more preferably 2 to 50% by mass, based on the total solid content of the photosensitive resin composition. Preferably, it is 0.5 to 60 parts by mass, more preferably 2 to 50 parts by mass with respect to 100 parts by mass of the total solid content of the photopolymerizable compound (A).

  Here, when the photosensitive resin composition of the present invention is applied as a material for forming a rib part of a hollow structure device, the content of the inorganic filler (D) is a fine pattern forming property required as a material for forming the rib part. From the viewpoint of satisfying and obtaining sufficient resin strength, it is preferably 0.5 to 50% by mass, more preferably 2 to 50% by mass, and still more preferably 5 to 45% by mass based on the total solid content of the photosensitive resin composition. %, More preferably 10 to 40% by weight, and (A) the total amount of the solid content of the photopolymerizable compound is preferably 100 to 50 parts by weight, preferably 0.5 to 50 parts by weight, more preferably 2 to 50 parts by weight. Parts, more preferably 5 to 45 parts by mass, and still more preferably 10 to 40 parts by mass.

  On the other hand, the content of the inorganic filler (D) when the photosensitive resin composition of the present invention is applied as a material for forming the lid is from the viewpoint of thick film formability and fine pattern formability. Based on the total solid content, it is preferably 0.5 to 60% by mass, more preferably 2 to 50% by mass, and still more preferably 5 to 40% by mass, and (A) the total solid content of the photopolymerizable compound is 100% by mass. The amount is preferably 0.5 to 60 parts by mass, more preferably 2 to 50 parts by mass, and still more preferably 5 to 40 parts by mass.

When the photosensitive resin composition containing an inorganic filler having an average aspect ratio of 30 to 100 and a volume average particle diameter of 5 to 50 μm is applied as a material for forming the “rib portion”, the content of the inorganic filler Is preferably 5 to 50% by mass, more preferably 10 to 50% by mass, still more preferably 15 to 45% by mass, and still more preferably 20 to 40% by mass, based on the total solid content of the photosensitive resin composition. (A) The total solid content of the photopolymerizable compound is preferably 100 parts by mass, preferably 5 to 50 parts by mass, more preferably 10 to 50 parts by mass, still more preferably 15 to 45 parts by mass, and even more. Preferably it is 20-40 mass parts.
If the content of the above inorganic filler falls within the above range, sufficient resin strength and high modulus of elasticity at high temperature can be obtained without adversely affecting the thick film formability and pattern formability of the resulting photosensitive resin composition. In addition, it is possible to obtain desired physical properties and characteristics as a cured resin such as low moisture absorption and low moisture permeability.

  In addition, when applying a photosensitive resin composition containing an inorganic filler having an average aspect ratio of 30 to 100 and a volume average particle diameter of 5 to 50 μm as a use for forming a “lid”, the inorganic filler The content of is preferably 5 to 60% by mass, more preferably 20 to 50% by mass, and still more preferably 20 to 40% by mass, based on the total solid content of the photosensitive resin composition. Preferably it is 5-60 mass parts with respect to 100 mass parts of solid content total amount of a polymeric compound, More preferably, it is 20-50 mass parts, More preferably, it is 20-40 mass parts.

  The photosensitive resin composition of the present invention further includes other components such as (E) sensitizer, (F) heat-resistant polymer, (G) thermal crosslinking agent, (H) thermal acid generator, and adhesion aid. Can be blended.

<(E) Sensitizer>
The photosensitive resin composition of the present invention can further contain (E) a sensitizer.
(E) Examples of the sensitizer include pyrazolines, anthracenes, coumarins, xanthones, oxazoles, benzoxazoles, thiazoles, benzothiazoles, triazoles, stilbenes, triazines, thiophenes, Examples include sensitizers composed of compounds such as phthalimides.
These (E) sensitizers can be used alone or in combination of two or more.

  (E) The content of the sensitizer is based on the total solid content of the photosensitive resin composition from the viewpoint of improving the sensitivity of the resulting photosensitive resin composition and improving the compatibility with the solvent. Preferably it is 0.1-1 mass%.

<(F) Heat resistant polymer>
The photosensitive resin composition of the present invention can further contain (F) a heat-resistant polymer.
(F) The heat-resistant polymer is preferably a polymer having high heat resistance from the viewpoint of processability. Specifically, polyimide, polyoxazole and precursors thereof, novolac resins such as phenol novolac and cresol novolac, Polyamideimide, polyamide and the like are preferable. These (F) heat resistant polymers can be used alone or in combination of two or more.

  (F) The content of the heat-resistant polymer improves the heat resistance and developability of the resulting photosensitive resin composition, and from the viewpoint of improving the resin hardness of the cured product of the composition. Preferably it is 1-50 mass% on the basis of the solid content whole quantity of a composition.

<(G) Thermal crosslinking agent>
The photosensitive resin composition of the present invention can further contain (G) a thermal crosslinking agent.
(G) As a thermal crosslinking agent, from the viewpoint of improving resin hardness, for example, an epoxy resin, a phenol resin substituted at the α-position with a methylol group or an alkoxymethyl group, and an N-position with a methylol group and / or an alkoxymethyl group Substituted melamine resins, urea resins and the like are preferred.
These (G) thermal crosslinking agents can be used alone or in combination of two or more.

  (G) The content of the thermal cross-linking agent is from the viewpoint of improving the heat resistance and developability of the resulting photosensitive resin composition and improving the resin hardness of the cured product of the composition. Preferably it is 1-20 mass% on the basis of the solid content whole quantity of a thing.

<(H) Thermal acid generator>
The photosensitive resin composition of the present invention can further contain (H) a thermal acid generator.
Examples of the (H) thermal acid generator include salts formed from strong acids such as onium salts and bases, imide sulfonates, and the like.
Examples of the onium salt include diaryliodonium salts such as aryldiazonium salts and diphenyliodonium salts, diaryliodonium salts, di (alkylaryl) iodonium salts such as di (t-butylphenyl) iodonium salts, and trialkyls such as trimethylsulfonium salts. Examples thereof include dialkylmonoarylsulfonium salts such as sulfonium salts and dimethylphenylsulfonium salts, diarylmonoalkyliodonium salts such as diphenylmethylsulfonium salts, and triarylsulfonium salts.
These (H) thermal acid generators can be used alone or in combination of two or more.

  (H) The compounding amount of the thermal acid generator is preferably 0.1 to 30 parts by mass, more preferably 0.2 to 20 parts by mass, and still more preferably 0.5 to 100 parts by mass of the component (A). -10 parts by mass.

<Adhesion aid>
Moreover, it is preferable that the photosensitive resin composition of this invention contains an adhesion assistant in order to improve the adhesiveness of the photosensitive resin composition and a board | substrate as needed.
Examples of the adhesion assistant include silane coupling agents such as γ-glycidoxysilane, aminosilane, and γ-ureidosilane.
These adhesion assistants can be used alone or in combination of two or more.
From the viewpoint of improving the adhesion between the photosensitive resin composition and the substrate, the blending amount of the adhesion assistant is preferably 0.1 to 10 parts by mass, more preferably 0, with respect to 100 parts by mass of the component (A). 4 to 3 parts by mass.

<Solvent>
In the photosensitive resin composition of the present invention, it is preferable to add a solvent in order to improve applicability to a substrate and improve workability.
The solvent to be used is not particularly limited. For example, polar solvents mainly composed of N-methyl-2-pyrrolidone, N, N-dimethylacetamide, N, N-dimethylformamide, propylene glycol monomethyl ether acetate, and the like, γ- Examples include butyrolactone. These solvents may be used alone or in combination of two or more.

(Physical properties of the cured product of the photosensitive resin composition)
The glass transition temperature of the cured product of the photosensitive resin composition of the present invention having the above composition is preferably 165 ° C. or higher, more preferably 180 ° C. or higher.
Moreover, the elasticity modulus at 150 degreeC of the hardened | cured material of the photosensitive resin composition of this invention becomes like this. Preferably it is 0.5 GPa or more, More preferably, it is 1.0 GPa or more, More preferably, it is 1.5 GPa or more. The upper limit of the elastic modulus at 150 ° C. is not particularly limited, but is preferably 10 GPa or less from a practical viewpoint.
In the present invention, the above elastic modulus is not only defined to increase mold resistance, but also in the prevention of falling and sagging of the rib portion formed from the photosensitive resin composition or the flatness of the lid portion. The required physical property value. Moreover, although the high temperature elasticity modulus of 150 degreeC or more of resin hardened | cured material exists in the tendency which becomes so high that glass transition temperature becomes high, it is not decided only by glass transition temperature. If the glass transition temperature becomes too high, the decrease in adhesive force and the increase in moisture absorption due to the generation of thermal stress may become significant. Therefore, in the present invention, it is preferable to pay attention to the elastic modulus at 150 ° C. as the physical property value defined for preventing the deformation of the hollow structure.

[Photosensitive film]
The photosensitive film of the present invention is a film having a photosensitive resin layer comprising at least the photosensitive resin composition of the present invention.
The photosensitive film of the present invention can be suitably used as a material for forming one or both of the rib portion and the lid portion constituting the hollow structure in an electronic component having a hollow structure.

The photosensitive film, for example, after dissolving the photosensitive resin composition of the present invention in the above-described solvent as necessary, is coated on a support film made of an organic film such as polyethylene terephthalate by various known methods. By drying and removing the solvent, a photosensitive resin layer can be formed and manufactured as a two-layer photosensitive film (dry film resist).
In addition, a protective film such as polyethylene terephthalate, polyethylene film, or polypropylene film may be laminated on the formed photosensitive resin layer to form a three-layer photosensitive film.
In addition, if the photosensitive resin layer formed from the photosensitive resin composition of the present invention has a self-supporting property, the supporting film can be peeled off to form a one-layer photosensitive film without the supporting film. .
The photosensitive resin composition of the present invention can be heated and melted and molded into a sheet using an extrusion molding machine or the like.

When the photosensitive film of the present invention is used as a material for forming a lid having a hollow structure, as described later, the support film may be used after being peeled after photopolymerization by light irradiation, or the photosensitive resin composition is used as it is. It can be used together with objects as a material for forming a lid.
In the present invention, instead of the above support film, a thermoplastic engineering plastic, a transparent or translucent heat-resistant plastic made of a thermosetting resin having a three-dimensional network structure, glass, ceramic, or the like can be used. These heat-resistant plastics, glass or ceramics are formed into a film or thin plate in which a photosensitive resin layer made of a photosensitive resin composition is formed in the same manner as the support film by using a thin film or thin plate. be able to. 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.

There is no restriction | limiting in particular in the thickness of a photosensitive film, According to a use, it can set suitably.
For example, when a support film or a support thin plate is used, the thickness of the support film or the support thin plate is preferably 10 μm to 3 mm. In addition, since the said thickness is suitably determined in consideration of the shape and thickness of a hollow structure device, and manufacture, the suitable range is wide.
Moreover, the thickness of the photosensitive resin layer is preferably 1 to 500 μm, and the thickness of the protective film is preferably 10 to 200 μm.

[Pattern formation method]
Next, the pattern forming method of the present invention will be described.
The pattern forming method of the present invention includes a step of laminating the above-described photosensitive resin composition or photosensitive film of the present invention on a substrate to form a photosensitive resin layer, and a predetermined portion of the photosensitive resin layer. An exposure step of irradiating an actinic ray through a mask to photo-cure the exposed portion, a developing step of removing a portion other than the exposed portion of the photosensitive resin layer using a developer, and the photosensitive resin layer And a thermosetting step of thermosetting the exposed portion to form a cured resin. Through these steps, for example, a desired pattern such as a rib pattern for forming a hollow structure can be formed.
Hereinafter, each process of the pattern formation method of this invention is demonstrated.

(Lamination process)
In the lamination step, a photosensitive resin film is formed by applying and drying or laminating the above-described photosensitive resin composition or photosensitive film on a substrate.
Examples of the substrate include a glass substrate, a semiconductor, a metal oxide insulator (such as TiO ₂ and SiO ₂ ), silicon nitride, and a ceramic piezoelectric substrate.
Moreover, it does not specifically limit as a coating method of the photosensitive resin composition, For example, methods, such as spin coating using a spinner, spray coating, dip coating, and roll coating, are mentioned. As a method for laminating the photosensitive film, it can be laminated using a laminator or the like.

When the photosensitive resin composition is applied on the substrate, the film thickness of the dried film (photosensitive resin layer) can be appropriately set depending on the application means, the solid content concentration and viscosity of the photosensitive resin composition, etc. From the viewpoint of improving the resolution, it is preferably 1 to 300 μm.
The resolution is good when the film thickness of the resulting coating is 300 μm or less. In addition, when using a photosensitive film, it is preferable to form so that the film thickness of the photosensitive resin layer may become said film thickness previously.
In order to obtain such a film thickness, the above-described photosensitive resin composition is dissolved with a solvent, and the viscosity of the resin composition is preferably 0.5 to 20 Pa · s, more preferably 1 to 1. It is preferable to adjust to 10 Pa · s.
Moreover, the solid content concentration of the photosensitive resin composition is preferably 20 to 80% by mass, more preferably 30 to 70% by mass.

  Then, a photosensitive resin layer can be formed on a board | substrate by drying for 1 minute-1 hour in a 60-120 degreeC temperature range using a hotplate, oven, etc.

(Exposure process)
In the next exposure step, the photosensitive resin layer laminated on the substrate is irradiated with actinic rays through a negative mask having a desired pattern, and the exposed portion is photocured.
Here, examples of actinic rays used for exposure include ultraviolet rays, visible rays, electron beams, and X-rays. Among these, ultraviolet rays or visible rays are preferable.

(Development process)
In the next development step, a portion other than the exposed portion (unexposed portion) of the photosensitive resin layer is removed using a developer. As the developer, an organic solvent or an alkaline aqueous solution can be used.
Examples of the organic solvent used as the developer include N-methylpyrrolidone, ethanol, cyclohexanone, cyclopentanone, propylene glycol methyl ether acetate, and the like.
Examples of the alkaline aqueous solution used as a developer include alkaline aqueous solutions such as sodium hydroxide, potassium hydroxide, sodium silicate, ammonia, ethylamine, diethylamine, triethylamine, triethanolamine, and tetramethylammonium hydroxide. .
Among these, propylene glycol methyl ether acetate is preferable from the viewpoint of development speed.

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

(Thermosetting process)
Further, after the development step, a heat curing step is performed in which the exposed portion of the photosensitive resin layer is thermally cured 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.
In addition, the pattern formation method of this invention is suitable as a method of forming the rib pattern for forming a hollow structure.

[Method for forming hollow structure]
Next, the method for forming the hollow structure of the present invention will be described.
The method for forming a hollow structure according to the present invention includes a photosensitive resin layer having a photosensitive resin layer according to the present invention, wherein a rib pattern is provided to form a hollow structure, and a lid portion of the hollow structure is formed on the rib pattern. Laminating step of laminating a film, an exposure step of irradiating a predetermined portion of the photosensitive resin layer with actinic rays and photocuring the exposed portion, and thermosetting the exposed portion of the photosensitive resin layer to cure the resin And a thermosetting step.
In addition, it is preferable that the said rib pattern is formed by the pattern formation method of the above-mentioned this invention.

The photosensitive film of the present invention can be used not only as a material for forming the above-described hollow rib, but also as a material for forming a lid.
When the photosensitive film of the present invention is applied as a lid, it is not always necessary to go through a development step between the exposure step and the thermosetting step.

However, if you want to control the shape of the lid, if you want to manufacture a plurality of hollow structure devices at the same time, and after exposing only the size corresponding to the lid of the individual hollow device through the mask, then unexposed parts around it In the case of dividing into individual pieces by developing, the exposure part of the photosensitive resin layer is subjected to an exposure process of irradiating an actinic ray through a mask and photocuring the exposed part in the exposure process. It is preferable to pass through a developing step in which the other portions are removed using the developer described above.
In addition, the lamination | stacking process, the exposure process, the removal process, and the thermosetting process in the formation method of the hollow structure of this invention can be performed similarly to the above-mentioned pattern formation method.

The film thickness of the photosensitive resin layer of the photosensitive film used for forming the lid is preferably 5 to 500 μm, more preferably 10 to 400 μm.
The final film thickness (total of the thickness of the photosensitive resin layer, the film serving as the substrate or the thin plate) of the lid formed through the curing step is preferably 10 μm to 3 mm, more preferably 20 μm to 2 mm. If the photosensitive resin composition of this invention is used, even if the thickness of a cover part is 10 micrometers, a shape can be maintained and the deformation | transformation on the high temperature / high pressure conditions at the time of a molding can also be suppressed. On the other hand, if the thickness of the lid portion is 3 mm or less, it is possible to avoid problems that may occur in manufacturing because the device having a hollow structure is too thick or the light transmission during exposure is reduced.
In addition, 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 the 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.

  If the provided rib pattern has a sufficient film thickness, a hollow structure may be formed by laminating a ceramic substrate, Si substrate, glass substrate, metal substrate, etc. as a lid. it can.

As described above, according to the method for forming a hollow structure of the present invention, a thick rib pattern can be collectively formed by photolithography, and a cured product of a photosensitive resin composition (or a film formed from the rib pattern) (or A hollow structure can be formed by sealing a sealing substrate such as ceramic as a lid.
In addition, the space of this hollow structure is moisture-proof by the surrounding photosensitive resin composition, and the hollow part is retained even at high temperature, so that a hollow structure such as a SAW filter, CMOS / CCD sensor, MEMS, etc. is required. It can be applied to electronic parts and is useful for downsizing, low profile and high functionality of electronic parts. The photosensitive resin composition of the present invention is particularly suitable as a material for forming a rib portion and a lid portion of a hollow structure of a SAW filter, and is particularly suitable as a material for forming a lid portion in that high reliability can be achieved. .

[Electronic parts]
The electronic component of the present invention has a hollow structure in which a rib portion and / or a lid portion having a hollow structure is formed using the above-described photosensitive resin composition or photosensitive film.
Hereinafter, a SAW filter (surface acoustic wave filter) will be described as an example of the electronic component of the present invention.

<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 for a rib portion formed using the photosensitive resin composition of the present invention is laminated on a substrate 10 on which a comb-shaped electrode 20 is formed. As the lamination method, a method similar to the method described in the pattern forming method can be used.

  The photosensitive resin composition of this invention is apply | coated so that the film thickness of the photosensitive resin layer 32 for rib parts may be normally 1-500 micrometers, preferably 1-300 micrometers similarly to the said pattern formation method.

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

  Next, as shown in FIG. 1A, a predetermined part of the photosensitive resin layer 32 for ribs is irradiated with actinic rays through a mask 60 having a desired pattern as required, and the exposed part is photocured. Let me. 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, a pattern was formed by removing a portion other than the exposed portion (unexposed portion) of the photosensitive resin layer 32 for the rib portion using an organic solvent-based developer. Then, the exposed part of the photosensitive resin layer 32 for rib part is thermosetted, and the rib part 30 which consists of resin cured material is formed. These exposure step, removal step, and thermosetting step can use the same method as the pattern forming method.

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 obtained by forming a film of the photosensitive resin composition of the present invention in advance, or a film formed in advance 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 can be used as a rib portion for forming a 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.

  FIG. 2 shows a SAW filter equipped with a metal ball for electrical connection with an external terminal after forming a rib portion and a lid portion using the photosensitive resin composition or photosensitive film of the present invention. Show. 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. Deformation that affects the characteristics can be sufficiently suppressed.

  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 for the wiring formed inside and on 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.

  A method for manufacturing the SAW filter shown in FIG. 2 is shown in FIG. FIG. 3 shows a method of forming the rib portion and the lid portion of the present invention only by UU 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. Through the steps of FIGS. 3A to 3B, a hollow space is formed on the wiring conductor 81 electrically connected to the comb-shaped electrode 20 on the substrate 10 by the same method as shown in FIG. 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. Then, the photosensitive resin layer 41 for lid part formed from the photosensitive resin composition or photosensitive film of the present invention laminated on the support film is laminated on the rib part 30, and UV exposure is performed through the mask. This is performed ((c) of 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 40 is subjected to development and then subjected to desmear treatment or the like in order to completely penetrate the hole 35 for forming the previously formed internal conductor ((d) in FIG. 3). . Further, the inner conductor 80 is formed inside the hole 35 formed in the rib portion and the lid portion by plating or the like, and the wiring is formed on the surface of the lid portion ((e) in FIG. 3). In the present invention, not only the plating method but also the inner conductor 80 is filled in the hole 35 formed in the rib portion and the lid portion by a conductor filling method using a resin paste containing a metal paste or metal powder. Can be formed. Through these steps, the wiring conductor wired to the comb-shaped electrode 20 on the substrate 10 is electrically connected to the wiring conductor 81 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 that is an electronic component having a hollow structure of the present invention ((f) in 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 FIG. 3C, after the photosensitive resin layer 41 for the lid portion is laminated on the rib portion 30 using a photosensitive film, the lid is covered with a laser in the step of FIG. A hole 35 for forming an internal conductor is formed inside the portion. 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 selected and used as appropriate according to the thickness of the rib portion, the shape of the internal conductor formed inside the rib portion, and the shape of the lid surface wiring pattern.

  FIG. 3 shows a method for manufacturing a SAW filter in which one surface wiring layer is formed on the surface of the lid. In the present invention, however, a portion corresponding to the lid has two or more wiring layers. You can also. FIG. 4 shows a wiring forming method for a SAW filter having two wiring layers in a portion corresponding to the lid. After forming the wiring conductor 81 on the surface of the lid portion 40 of the SAW filter by the same method as shown in FIGS. 3A to 3E, the photosensitive film of the present invention is laminated and the photosensitive resin for the lid portion is formed. After forming the layer 41 (FIG. 4A), UV exposure is performed using a mask 60 in which a portion corresponding to the diameter of the external connection electrode is shielded from light (FIG. 4B), and solvent development is performed. Holes for external connection electrodes are formed in the uppermost layer of the lid 40 ((c) in FIG. 4). Next, an external connection electrode is formed by plating, and finally, a metal ball 70 is mounted on the surface of the lid by reflow or the like to obtain a SAW filter that is an electronic component having a hollow structure of the present invention (see FIG. 4 (d)). At that time, the metal ball is directly mounted via the anti-oxidation metal film (Ni, Au, etc.) of the electrode for the external electrode (the left figure in FIG. 4 (d)), but the lid portion is formed using a photoresist or the like. After forming the wiring layer again on the surface, a method of mounting a metal ball may be employed (the right view of FIG. 4D).

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. 5, 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 balls are mounted, and after the sealing, the metal balls are mounted on the surface opposite to the sealed surface of the substrate by reflow. However, after the metal ball is mounted, sealing with a sealing material may be performed. FIG. 5 shows one SAW filter 100 sealed with a sealing material. However, the SAW filter of the present invention includes a large number of AW filters formed on one substrate with a sealing material. It can also be obtained by cutting into individual pieces after sealing.

  FIGS. 6A to 6J show a SAW filter obtained by sealing a large number of SAW filters formed on one substrate in a lump and then dicing (cutting) them into pieces. A manufacturing method is shown. First, a large number of SAW filters having the comb-shaped electrode 20 and the wiring conductor 81 are formed on one substrate, and then the rib portion and / or the lid portion are formed using the photosensitive resin composition or the photosensitive film of the present invention. It forms ((a)-(e) of FIG. 6). In this manufacturing method, wiring conductors 81 for electrical connection with external connection electrodes are disposed on both outer sides of comb-shaped electrode 20. Next, in order to form an external connection electrode, a photoresist 50 is applied to the entire surface of the substrate, and ultraviolet light exposure is performed using a mask in which a portion corresponding to the diameter of the external connection electrode is shielded from light, and development is performed. A photoresist opening 51 for forming an external connection electrode is provided ((f) of FIG. 6). Subsequently, after the external connection electrode 82 is formed by a plating method or a conductor filling method, the photoresist 50 is removed with a photoresist stripping solution ((g) in FIG. 6). Further, a cleaning process that completely removes the photoresist residue present on the surface of the substrate or the lid may be employed. After that, the hollow structure portion is collectively sealed by the transfer mold method using the resin sealing material 90 ((h) in FIG. 6), and the metal balls 70 are mounted by reflow ((i in FIG. 6). )), And the SAW filter 100 is obtained by dividing into pieces by a method such as dicing (cutting) ((j) in FIG. 6). In the present invention, the metal balls 70 may be mounted in the state of individual packages after the substrate dicing process.

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 preferable that the cover part 40 and / or the rib part 30 do not deform | transform at the temperature of 150-180 degreeC. From the viewpoint of obtaining such characteristics, the glass transition temperature of the material (cured product) forming the lid portion 40 and / or the rib portion 30 is preferably 165 ° C. or higher, more preferably 180 ° C. or higher.
Moreover, the elastic modulus at 150 ° C. of the material (cured product) is preferably 0.5 GPa or more, more preferably 1.0 GPa or more, and further preferably 1.5 GPa or more. The upper limit of the elastic modulus at 150 ° C. of the material is not particularly limited, but is 10 GPa or less from a practical viewpoint.

  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 space of the hollow structure 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.

[Synthesis Example 1]
(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 172.0 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 / When g was reached, stirring was stopped to obtain a solution of a compound represented by the following formula (12) which is a photopolymerizable unsaturated compound. The solid content of the obtained solution was 80% by mass. In addition, as a compound represented by following formula (12), commercially available FA-7220M (made by Hitachi Chemical Co., Ltd.) etc. are mentioned, for example.

[Synthesis Example 2]
(Synthesis of amide acrylate)
An amide acrylate was synthesized by the same method as the synthesis of the amide methacrylate of Synthesis Example 1 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.

[Examples 1-27 and Comparative Examples 1-7]
(A) Photopolymerizable compound, (B) Photopolymerization initiator, (C) Thermal polymerization initiator, (D) Inorganic filler, and silane coupling agent shown in Tables 1 to 3 below, respectively. (Mass part) to obtain a solution of the photosensitive resin composition of Examples 1-27 and Comparative Examples 1-7. In addition, the number in Table 1-Table 3 has shown the mass part of solid content.

Each component in Tables 1 to 3 is shown below. In addition, the number (functional group number) and weight average molecular weight (Mw) of the (meth) acryloyl group which a urethane type compound has are as showing below. Here, the weight average molecular weight (Mw) is determined by GPC method using tetrahydrofuran as a solvent, and details of GPC method are as follows.
Device name: HLC-8220GPC (product name, manufactured by Tosoh Corporation)
Column: Gelpack R-420, R-430, R-440 (three connected)
Detector: RI detector Column temperature: 40 ° C
Eluent: Tetrahydrofuran Flow rate: 1 ml / min Standard substance: Polystyrene

Component (A) “amide acrylate”: the amide acrylate obtained in Synthesis Example 2 above.
“Amide methacrylate”: Amide methacrylate obtained in Synthesis Example 1 above.
"UN-952": trade name, manufactured by Negami Kogyo Co., Ltd. A urethane compound having an acryloyl group. Functional group number = 10, Mw = 6500-11000.
"UN-904": trade name, manufactured by Negami Kogyo Co., Ltd. A urethane compound having an acryloyl group. Number of functional groups = 10, Mw = 4900.
"UN-2600": trade name, manufactured by Negami Kogyo Co., Ltd. A urethane compound having an acryloyl group. Number of functional groups = 2, Mw = 2500.
"UN-6060PTM": trade name, manufactured by Negami Kogyo Co., Ltd. A urethane compound having a methacryloyl group. Functional group number = 2, Mw = 6000.
"UN-3320HA": trade name, manufactured by Negami Kogyo Co., Ltd. A urethane compound having an acryloyl group. Number of functional groups = 6, Mw = 1500.
"UN-9200A": trade name, manufactured by Negami Kogyo Co., Ltd. A urethane compound having an acryloyl group. Functional group number = 2, Mw = 15000.
"UN-3320HS": trade name, manufactured by Negami Kogyo Co., Ltd. A urethane compound having an acryloyl group. Number of functional groups = 15, Mw = 5000.
"UN-6301": trade name, manufactured by Negami Kogyo Co., Ltd. A urethane compound having an acryloyl group. Functional group number = 2, Mw = 33000.
"EA-6340": trade name, manufactured by Nakamura Chemical Co., Ltd. Tetrahydrophthalic anhydride modified vinyl group-containing phenolic epoxy resin.
-“A-DPH”: trade name, manufactured by Shin-Nakamura Chemical Co., Ltd. Dipentaerythritol.

(B) component * "IRGACURE-OXE-01": a brand name, the product made from BASF. Oxime ester compounds (1,2-octanedione-1- [4- (phenylthio) phenyl] -2- (O-benzoyloxime)).
"IRGACURE-OXE-02": trade name, manufactured by BASF Oxime ester compounds (1- [9-ethyl-6- (2-methylbenzoyl) -9H-carbazol-3-yl] ethanone 1- (O-acetyloxime)).
・ "DAROCURE-TPO": trade name, manufactured by BASF. Acylphosphine oxide compounds (2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide).
"IRGACURE-819": trade name, manufactured by BASF Acylphosphine oxide compounds (bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide).
"IRGACURE-651": trade name, manufactured by BASF Alkylphenone compounds (2,2-dimethoxy-1,2-diphenylethane-1-one).
"IRGACURE-369": trade name, manufactured by BASF Alkylphenone compound (2-benzyl-2dimethylamino-1- (4-morpholinophenyl) -butanone-1).

Component (C) “Park Mill D”: trade name, manufactured by NOF Corporation. Organic peroxide, dicumyl peroxide.
"Perhexa V": trade name, manufactured by NOF Corporation. Organic peroxide, n-butyl 4,4-di- (t-butylperoxy) valerate.

(D) Ingredient "Mica A": Mica. Aspect ratio 90, volume average particle size (D ₅₀ ) 27 μm.
・ "Mica B": Mica. An aspect ratio of 30 and a volume average particle diameter (D ₅₀ ) of 5 μm.
“Silica A”: spherical silica. Volume average particle diameter (D ₅₀ ) 0.5 μm.
Silane coupling agent “AY43-031”: trade name, manufactured by Toray Dow Corning.

  The following evaluation was performed using the solution of the photosensitive resin composition obtained in Examples and Comparative Examples. The evaluation results are shown in Tables 4 and 5.

<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 to produce a test substrate. 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 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 resist pattern after development was washed with n-butyl acetate, observed after drying, and the solvent resistance was evaluated based on the following criteria as shown in FIG. In FIG. 7, 11 indicates a silicon substrate, and 52 indicates a photosensitive resin layer formed from the photosensitive resin composition.
A: As shown in FIG. 7A, a hole diameter of 60 μm is opened, the opening is rectangular, and there is no residue after development.
B: As shown in FIG. 7B, the hole diameter is 60 μmφ, but the opening has a tapered shape and has an opening with a sash.
C: As shown in FIG. 7C, the hole diameter of 60 μmφ is not opened and the via is buried.

<Hollow structure 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 to produce a test substrate. About the test board | substrate which formed this photosensitive resin layer, the exposure amount of 200mJ / was used using the proximity exposure machine (brand name: UX-1000SM) made from USHIO through the negative mask which has a grid size 1mm □ opening pattern. It was exposed photosensitive resin layer in cm ^2. This test substrate was developed and cured to obtain a cured film pattern having openings in a lattice pattern.

  Separately, using a polyethylene phthalate film having a thickness of 50 μm as a support film, using the photosensitive resin composition solutions of Examples and Comparative Examples on the support film, a photosensitive resin layer having a thickness of 30 μm. The photosensitive film which formed was produced. And the said photosensitive film was affixed on the test board | substrate which has said cured film pattern, and the hollow structure was formed.

Next, the photosensitive resin film in the form of a film was exposed at an exposure amount of 200 mJ / cm ² using a proximity exposure machine (trade name: UX-1000SM) manufactured by Ushio Electric. The test substrate was cured at 120 ° C. for 30 minutes, at 160 ° C. for 30 minutes, and at 200 ° 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 structure retention was evaluated based on the above criteria.
-A: The hollow part can be hold | maintained and the film cured film is not dripping at all.
-B: Although the hollow part is hold | maintained, sagging is seen in a film even a little.
C: The film falls and the hollow part is crushed.

<Measurement of elastic modulus, 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 layer was formed to produce a test substrate. For the test substrate on which the photosensitive resin layer is formed, the photosensitive resin layer is exposed at an exposure amount of 200 mJ / cm ² using a proximity exposure machine (trade name: UX-1000SM) manufactured by USHIO ELECTRIC CO., LTD. I let you. This photosensitive resin 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 off from the silicon substrate, and the elastic modulus at 150 ° C. and the glass transition temperature of the peeled cured film were measured using 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 (25 ° C.) to 300 ° C., temperature increase rate: 5 ° C./min, test frequency: 1 Hz, and distance between chucks: 20 mm.

<Evaluation of PCT 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 layer was formed to produce a test substrate. For the test substrate on which the photosensitive resin layer is formed, the photosensitive resin layer is exposed at an exposure amount of 200 mJ / cm ² using a proximity exposure machine (trade name: UX-1000SM) manufactured by USHIO ELECTRIC CO., LTD. I let you. Thereafter, the photosensitive resin layer was cured by heating at 120 ° C. for 30 minutes, 160 ° C. for 30 minutes, and 220 ° C. for 60 minutes. After leaving this test substrate under the conditions of 121 ° C., 100% RH (relative humidity) and 2 atm for 100 hours, the appearance of the cured film was visually observed, and the PCT resistance was evaluated based on the following criteria. did.
A: The cured film is not turbid, peeled, swollen, or cracked.
B: Any one of slight turbidity, peeling, swelling, and cracks can be seen in the cured film.
C: Any one of turbidity, peeling, swelling, and cracks in the cured film can be seen.

<Reflow crack 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 layer was formed to produce a test substrate. For the test substrate on which the photosensitive resin layer is formed, the photosensitive resin layer is exposed at an exposure amount of 200 mJ / cm ² using a proximity exposure machine (trade name: UX-1000SM) manufactured by USHIO ELECTRIC CO., LTD. I let you. Thereafter, the photosensitive resin 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 left on a hot plate at 260 ° C. for 30 seconds, then returned to room temperature (25 ° C.) and held for 30 seconds, one cycle was repeated a total of 5 cycles, and the appearance of the test substrate was visually observed. The reflow crack resistance was evaluated based on the following criteria.
A: No appearance abnormality.
B: Crack peeling is observed on a part of the substrate.
C: Crack peeling is observed on the entire surface of the substrate.

  According to the evaluation results of each Example shown in Table 4, from (A) a photopolymerizable compound having at least one ethylenically unsaturated group and (B) an oxime ester compound and / or an acylphosphine oxide compound. It turns out that the photosensitive resin composition containing the photoinitiator which becomes becomes evaluation of A or B or more, and there exists an outstanding effect (Examples 1-27). In this invention, if evaluation of each characteristic shown in Table 4 is B or more, it can be said that it is a photosensitive resin composition suitable as a formation material of a rib part and / or a cover part.

Except for Example 16, the photosensitive resin composition of the present invention has an elastic modulus at 150 ° C. of 0.5 GPa or more, and the higher the high-temperature elastic modulus, the better the hollow structure retention. Further, the higher the glass transition temperature of the photosensitive resin composition, the more the hollow structure retention tends to be improved. However, the elastic modulus at 150 ° C. is not necessarily determined only by the glass transition temperature. In Example 16, since the elastic modulus at 150 ° C. is low, the hollow structure retainability is slightly inferior to those of other examples, but the photopolymerizable compound forms a cured resin having excellent toughness and adhesiveness. Since it is comprised only by the urethane compound to perform, the evaluation result which was excellent about the characteristic other than that was shown.
Furthermore, in addition to (A) a photopolymerization compound comprising at least one ethylenically unsaturated group and (B) an oxime ester compound and / or an acylphosphine oxide compound, (C) thermal polymerization By containing an initiator and / or (D) an inorganic filler, the high-temperature elastic modulus can be improved, so that the hollow structure retainability can be greatly improved.

  Since the photosensitive resin composition containing the thermal polymerization initiator (C) of the present invention has an effect of accelerating the thermal curing of the exposed portion in the thermal curing step performed after the exposure step and the development step, the glass transition temperature. Tends to be slightly higher. Accordingly, it can be seen that the retention of the hollow structure is improved (see the comparison between Example 1 and Example 25, the comparison between Example 10 and Example 26, and the comparison between Example 16 and Example 27). .

  In addition, (D) the photosensitive resin composition containing an inorganic filler shows almost no decrease in the glass transition temperature or adhesiveness of the cured resin, and on the contrary, the moisture absorption rate becomes small, so that PCT resistance and reflow resistance are reduced. The crack property tends to be the same as or better than the composition not containing an inorganic filler. In particular, when mica having a high aspect ratio and a relatively large particle size is contained as an inorganic filler, various characteristics can be greatly improved while maintaining a usable resolution (Examples 22 and 24). 27). In addition, even when spherical silica having a small particle diameter is used as the inorganic filler (D), the hollow structure retainability can be improved according to the blending amount thereof (Example 23). Although the photosensitive resin composition of the present invention does not contain an inorganic filler, it already has excellent hollow structure retention, high temperature elastic modulus and moist heat resistance, but in order to further improve these properties, it has a small particle size. Inorganic fillers can be used.

  On the other hand, according to the evaluation result of each comparative example shown in Table 5, the photosensitive resin composition containing alkylphenone photopolymerization initiators (IRGACURE-651 and IRGACURE-369) as the component (B) As a result, it was difficult to apply as a forming material for a rib part or a lid part for forming a hollow structure due to a decrease in the hollow structure retainability (Comparative Examples 1 to 7). Although these photopolymerization initiators can improve the resolution at the time of pattern formation by adjusting the content, they have almost no effect on improving the hollow structure retainability (Comparative Examples 4, 6, and 7). . This is thought to be because the photo-curing of the photosensitive resin composition is not uniform and the cured product with a low molecular weight remains even after the heat curing step, so that the hollow structure retainability could not be improved. It is unknown.

  As described above, the photosensitive resin composition of the present invention has a good resolution, excellent moisture and heat resistance, a cured product has a high elastic modulus at a high temperature, and excellent hollow structure retention. It is suitable as a material for forming a rib part and / or a cover part. Further, by applying a photosensitive film using the photosensitive resin composition of the present invention to a rib pattern forming method and a hollow structure forming method, a low-cost and highly reliable hollow electronic component, Specifically, a SAW filter can be manufactured.

DESCRIPTION OF SYMBOLS 10 Substrate 11 Silicon substrate 20 Comb electrode 30 Rib portion 32 Photosensitive resin layer for rib portion 35 Hole 40 Lid portion 41 Photosensitive resin layer for lid portion Photoresist 51 Photoresist opening portion 52 Photosensitive resin layer 60 Mask 70 Metal ball 80 Internal conductor 81 Wiring conductor 82 External connection electrode 90 Sealant 100 SAW filter

Claims (12)

(A) a photopolymerizable compound having at least one ethylenically unsaturated group, and (B) a photopolymerization initiator, and (B) an oxime ester compound and / or an acylphosphine oxide as the photopolymerization initiator. A photosensitive resin composition comprising a compound ,
(A) The photopolymerizable compound having at least one ethylenically unsaturated group contains at least an acrylate compound or a methacrylate compound having an amide group and a urethane compound having an acryloyl group or a methacryloyl group in at least one molecule. And
The photosensitive resin composition whose content of the said (B) photoinitiator is 0.5-3 mass parts with respect to 100 mass parts of solid content total amount of the said (A) photopolymerizable compound . (B) The photoinitiator of the photosensitive resin of Claim 1 containing at least any one of the compounds represented by following formula (1), (2), (3) and (4). Composition.

[In Formula (1), X ₁ and X ₂ each independently represent a hydrogen atom, a cyclic, linear or branched alkyl group having 1 to 12 carbon atoms, or an aryl group, and the alkyl group and The aryl group may be substituted with a substituent selected from the group consisting of a halogen atom, an alkoxy group having 1 to 6 carbon atoms, and an aryl group. X ₃ and X ₄ each independently represent a halogen atom, an alkyl group having 1 to 12 carbon atoms, a cyclopentyl group, a cyclohexyl group, a phenyl group, a benzyl group, a benzoyl group, an alkanoyl group having 2 to 12 carbon atoms, or 2 carbon atoms. -12 alkoxycarbonyl groups or a phenoxycarbonyl group is shown. p1 and p2 each independently represent an integer of 0 to 5. ]

Wherein (2), _{X 5} represents an alkanoyl group or a benzoyl group having 2 to 20 carbon atoms. X ₆ is an alkyl group having 1 to 12 carbon atoms, an alkanoyl group having 2 to 12 carbon atoms, an alkenoyl group having 4 to 6 carbon atoms in which a double bond is not conjugated with a carbonyl group, a benzoyl group, or 2 to 6 carbon atoms. An alkoxycarbonyl group or a phenoxycarbonyl group. X ₇ is a hydrogen atom, a halogen atom, an alkyl group having 1 to 12 carbon atoms, a cyclopentyl group, a phenyl group, a benzyl group, a benzoyl group, an alkanoyl group having 2 to 12 carbon atoms, an alkoxycarbonyl group having 2 to 12 carbon atoms, Or a phenoxycarbonyl group is shown. X ₈ , X ₉ and X ₁₀ are each independently a halogen atom, an alkyl group having 1 to 12 carbon atoms, a cyclopentyl group, a cyclohexyl group, a phenyl group, a benzyl group, a benzoyl group, an alkanoyl group having 2 to 12 carbon atoms, An alkoxycarbonyl group having 2 to 12 carbon atoms or a phenoxycarbonyl group is shown. p3, p4 and p5 each independently represent an integer of 0 to 5. ]

Wherein _{(3), R 1, R} 2 and _{R 3} each independently represent an alkyl group or aryl group having 1 to 20 carbon atoms. ]

[In formula (4), R ₄ , R ₅ and R ₆ each independently represents an alkyl group or aryl group having 1 to 20 carbon atoms. ] (B) The photoinitiator of the photosensitive resin of Claim 2 containing any one of the compounds represented by following formula (5), (6), (7) and (8) at least. Composition.

Wherein _(5), X 2, _{X 3} and _{X 4,} the general formula (1) as synonymous. X ₁₁ is independently a halogen atom, an alkyl group having 1 to 12 carbon atoms, a cyclopentyl group, a cyclohexyl group, a phenyl group, a benzyl group, a benzoyl group, an alkanoyl group having 2 to 12 carbon atoms, or an alkyl group having 2 to 12 carbon atoms. An alkoxycarbonyl group or a phenoxycarbonyl group is shown. p1 and p2 are synonymous with the said General formula (1). p6 represents an integer of 0 to 5. ]

[In the formula (6), X ₆ , X ₇ , X ₈ , and X ₉ are as defined in the above formula (2). X ₁₂ is independently a halogen atom, an alkyl group having 1 to 12 carbon atoms, a cyclopentyl group, a cyclohexyl group, a phenyl group, a benzyl group, a benzoyl group, an alkanoyl group having 2 to 12 carbon atoms, or an alkyl group having 2 to 12 carbon atoms. An alkoxycarbonyl group or a phenoxycarbonyl group is shown. X ₁₃ represents a cyclic, linear or branched alkyl group having 1 to 12 carbon atoms, or a phenyl group. p3 and p4 are synonymous with the said General formula (2). p7 represents an integer of 0 to 5. ]

[In Formula (7), R < ₁₁ >, R < ₁₂ >, R < ₁₃ > shows a C1-C6 alkyl group or a C1-C4 alkoxy group each independently. m1, m2, and m3 each independently represent an integer of 0 to 5. When m1, m2, and m3 are 2 or more, a plurality of R ₁₁ , R ₁₂ , and R ₁₃ may be the same or different. ]

[In formula (8), R < ₁₄ >, R < ₁₅ >, R < ₁₆ > shows a C1-C6 alkyl group or a C1-C4 alkoxy group each independently. n1, n2, and n3 each independently represents an integer of 0 to 5. When n1, n2 and n3 are 2 or more, a plurality of R ₁₄ , R ₁₅ and R ₁₆ may be the same or different. ] Furthermore, (D) The photosensitive resin composition in any one of Claims 1-3 containing an inorganic filler. The elastic modulus at 0.99 ° C. of the cured product of the photosensitive resin composition The photosensitive resin composition according to any one of claims 1 to 4 or more 0.5 GPa. The photosensitive resin composition according to any one of claims 1 to 5 , which is used as a material for forming one or both of a rib part and a lid part constituting the hollow structure in an electronic component having a hollow structure. The photosensitive film which has the photosensitive resin layer which consists of the photosensitive resin composition in any one of Claims 1-6 . A lamination step of laminating the photosensitive resin composition according to any one of claims 1 to 6 or the photosensitive film according to claim 7 on a substrate to form a photosensitive resin layer, and the photosensitive resin. An exposure step of irradiating a predetermined portion of the layer with actinic rays through a mask to photo-cure the exposed portion, a developing step of removing a portion other than the exposed portion of the photosensitive resin layer using a developer, and the photosensitive The pattern formation method which has a thermosetting process which thermosets the said exposure part of a conductive resin layer and forms resin cured | curing material. A lamination step of providing a rib pattern to form a hollow structure on the substrate, and laminating the photosensitive film having the photosensitive resin layer according to claim 7 on the rib pattern; and a predetermined of the photosensitive resin layer A method for forming a hollow structure, comprising: an exposure step of irradiating a portion with actinic rays to photocure an exposed portion; and a thermosetting step of thermally curing the exposed portion of the photosensitive resin layer to form a cured resin. . The method for forming a hollow structure according to claim 9 , wherein the rib pattern is formed by the pattern forming method according to claim 8 . An electron having a hollow structure in which a rib part and / or a lid part of a hollow structure is formed using the photosensitive resin composition according to any one of claims 1 to 6 or the photosensitive film according to claim 7. parts. The electronic component according to claim 11 , wherein the electronic component is a surface acoustic wave filter.