JP5072101B2 - Photosensitive resin composition for MEMS and cured product thereof - Google Patents

Description

   The present invention relates to a photoimageable epoxy resin composition and a permanent cured product thereof, which can be processed by ultraviolet (UV) lithography or imprinted using hot embossing. Mechanical system) parts, micro machine parts, micro fluid parts, μ-TAS (micro total analysis system) parts, inkjet printer parts, micro reactor parts, conductive layers, LIGA parts, molds and stamps for micro injection molding and hot embossing, The present invention relates to screens or stencils for micro printing applications, MEMS and semiconductor package parts, BioMEMS and biophotonic devices, and compositions useful in the production of printed wiring boards and laminates thereof and cured products thereof.

  Photolithographically processable resists have recently been widely used in semiconductor and MEMS / micromachine applications. In such an application, photolithography is achieved by patterning exposure on a substrate and then developing with a developer to selectively remove exposed or non-exposed areas. Resist (photoresist) that can be processed by photolithography includes a positive type or a negative type, a type that can be dissolved in a developing solution by exposure is a positive type, and a type that is also insoluble is a negative type. Advanced electro-package applications and MEMS applications require not only the ability to form a uniform spin coating film, but also a high aspect ratio, a straight sidewall shape in a thick film, and high adhesion to a substrate. Here, the aspect ratio is an important characteristic calculated by resist film thickness / pattern line width and showing the performance of photolithography.

  Photoresist polymerization initiators such as polyfunctional bisphenol A novolak type epoxy resin (EPON SU-8 resin made by Resolution Performance Products) and CYRACURE UVI-6974 made by Dow Chemical A negative-type chemically amplified photoresist composition comprising a propylene carbonate solution of an aromatic sulfonium hexafluoroantimonate as a cationic polymerization initiator is known. Since the photoresist composition has very low light absorption in the wavelength range of 350 to 450 nm, it is known as a photoresist composition that can be processed by thick film photolithography. This photoresist composition is spin-coated or curtain-coated on various substrates, and then the solvent is evaporated by baking to form a solid photoresist layer having a thickness of 100 μm or more, and further contact exposure, proximity exposure or Photolithographic processing is performed by irradiating near ultraviolet light through a photomask using various exposure methods such as projection exposure. Subsequently, a negative image of a high-resolution photomask can be formed on the substrate by immersing in a developing solution and dissolving the non-exposed areas.

  For example, Patent Document 1 maintains the characteristics such as good image resolution, thermal stability, chemical resistance and solvent resistance of the EPON SU-8 resin-based compound by blending a specific epoxy resin, Techniques for improving properties such as adhesion, delamination, cracking, crazing, stress and flexibility are disclosed. However, there is no description about the photocationic polymerization initiator contained in the composition of the invention, and nothing is mentioned about the adhesion after the pressure cooker test (PCT) due to the difference in the photocationic polymerization initiator.

  On the other hand, in the field of MEMS parts, MEMS, and semiconductor packages, it is known that the physical properties of the package material are large and affect the reliability of the device. MEMS and semiconductor elements are greatly affected by changes in ambient temperature and humidity, or fine dust and dirt, which deteriorate their characteristics and are easily damaged by mechanical vibrations and impacts. In order to protect MEMS and semiconductor elements from these external factors, it is well known that they are sealed in a ceramic box or resin and used as a package.

  In manufacturing this hollow type package, the hermetic sealing method using metal or ceramics is essentially non-moisture permeable, but has disadvantages such as high manufacturing cost and poor dimensional accuracy. On the other hand, in the case of resin sealing, the manufacturing cost is relatively low and the dimensional accuracy is high, but the resin basically has a moisture diffusion coefficient, and gradually passes moisture over time, so that the semiconductor element There is a problem in that the characteristics of the glass are deteriorated or moisture permeated into the inside of the package maintaining airtightness causes the glass surface to condense, resulting in lack of reliability (Patent Document 2).

Published Patent Publication 2007-522531 Published patent publication 2005-217212

In the conventional photosensitive resin composition using a polyfunctional epoxy resin such as a novolak-type epoxy resin, the sensitivity of the photocation polymerization initiator contained is low, so that it is necessary to contain a large amount of initiator or a short amount of initiator. There was a problem that the mask pattern could not be faithfully reproduced in time. Moreover, although the photocationic polymerization initiator containing hexafluoroantimonate ion (SbF ₆ ⁻ ) is relatively high in sensitivity, there is a problem in that its use is limited due to toxicity problems. On the other hand, in the field of MEMS parts, MEMS, and semiconductor packages, there has been a problem that due to the moisture resistance of the resin composition and the like, the adhesive force decreases with time and the reliability of the device is greatly reduced.

  The present invention has been made in view of the conventional circumstances as described above, and its problems are that it has good image resolution, thermal stability, chemical resistance and solvent solubility, and is highly sensitive and pressure-sensitive. It aims at providing the photosensitive resin composition which the adhesiveness to the board | substrate after a cooker test (PCT) does not fall.

  In order to solve the above-mentioned problems, the present inventors have intensively studied and, as a result, prepared a photosensitive resin composition by combining a specific epoxy resin and a specific photocationic polymerization initiator. It has been found that if a resin pattern is formed using a resin composition, it is possible to form a highly sensitive pattern that does not deteriorate the adhesion to the substrate after the pressure cooker test.

That is, the present invention
(1) The following formula (1)

(In Formula (1), R ₁ represents an alkyl group or an aryl group, R ₂ and R ₃ each independently represents an alkyl group, an aryl group, or an alkenyl group, Y represents a fluorine atom or a chlorine atom, and Z represents a fluorine atom) A phenyl group substituted with two or more groups selected from the group consisting of an atom, a cyano group, a nitro group, and a trifluoromethyl group, m represents an integer of 0 to 3, and n represents an integer of 1 to 4, m + n = 4.)
A photosensitive resin composition for MEMS, comprising a photocationic polymerization initiator (A) represented by formula (A) and an epoxy resin (B) having two or more epoxy groups in one molecule;
(2) The photosensitive resin composition for MEMS according to (1), wherein the photosensitive resin composition for MEMS is for a package;
(3) The cationic photopolymerization initiator (A) is represented by the following formula (2)

The photosensitive resin composition for MEMS according to the preceding item (1) or (2), which is a photocationic polymerization initiator (A-1) represented by:
(4) The softening point of the epoxy resin (B) is 40 ° C. or higher and 120 ° C. or lower and the epoxy equivalent is 150 to 500 / eq. The photosensitive resin composition for MEMS according to any one of (1) to (3) above,
(5) The epoxy resin (B) is represented by the following formula (3)

(In Formula (3), each R independently represents a glycidyl group or a hydrogen atom . K represents an average value and is a real number in the range of 0 to 30.)
An epoxy resin (B-1) represented by the following formula (4)

(In the formula (4), each R _1, R _2, and R _3, .p represents an alkyl group having independently from one to four hydrogen atoms or carbon atoms in the range of 1 to 30 shows the average value A real number.)
An epoxy resin (B-2) represented by the following formula (5)

(In Formula (5), n and m are average numbers and are independently real numbers in the range of 1 to 30, and R ₄ and R ₅ each independently have a hydrogen atom or 1 to 4 carbon atoms. Represents an alkyl group or trifluoromethyl.)
An epoxy resin (B-3) represented by the following formula (6)

(In Formula (6), n shows an average value and is a real number in the range of 1 to 30.)
An epoxy resin (B-4) represented by the following formula (7)

The photosensitive material for MEMS according to any one of (1) to (4) above, which contains one or more types of epoxy resins selected from the group consisting of epoxy resins (B-5) represented by Functional resin composition,
(6) A cured product obtained by curing the photosensitive resin composition for MEMS according to any one of (1) to (5) above,
(7) A laminate in which the MEMS photosensitive resin composition according to any one of (1) to (5) is sandwiched between base materials,
(8) A cured product obtained by curing the laminate according to (7) above,
About.

The photosensitive resin composition according to the present invention has good image resolution, thermal stability, chemical resistance and solvent solubility, is highly sensitive and does not deteriorate adhesion to the substrate after the pressure cooker test (PCT). Therefore, it is suitably used as a photosensitive resin composition for MEMS.

Hereinafter, embodiments of the present invention will be described.
The photosensitive resin composition of the present invention, contains an epoxy resin (B) having two or more epoxy groups cationic photopolymerization initiator represented before following formula (1) and (A) in a molecule It is possible to form a pattern that is highly sensitive and does not deteriorate the adhesion to the substrate after the pressure cooker test. Furthermore, since the above composition does not contain a highly toxic antimony compound, the load on the human body and the environment can be reduced.

  The cationic photopolymerization initiator (A) in the present invention generates cations upon irradiation with radiation such as ultraviolet rays, far ultraviolet rays, excimer lasers such as KrF and ArF, X-rays and electron beams, and the cations are polymerization initiators. It is a compound that can be used as an energy-sensitive linear acid generator.

Next, the structure of the photocationic polymerization initiator (A) in the present invention will be described in detail.
The photocationic polymerization initiator (A) used in the photosensitive resin composition of the present invention is represented by the formula (1). First, the cation part in Formula (1) is demonstrated.

Substituents denoted by -OR ₁ is characterized in that is bonded to the 4-position to the carbonyl group attached to the naphthalene ring in the formula (1), R ₁ represents an alkyl group or an aryl group. That is, the substituent represented by —OR ₁ represents an alkoxyl group or an aryloxy group.

Examples of the alkyl group in the substituent R ₁ in the formula (1) include linear, branched, monocyclic or condensed polycyclic alkyl groups having 1 to 18 carbon atoms. Specific examples include a methyl group, Ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, dodecyl, octadecyl, isopropyl, isobutyl, isopentyl, sec-butyl, t-butyl Group, sec-pentyl group, t-pentyl group, t-octyl group, neopentyl group, cyclopropyl group, cyclobutyl, cyclopentyl group, cyclohexyl group, adamantyl group, norbornyl group, boronyl group, 4-decylcyclohexyl group, etc. However, it is not limited to these.

Examples of the aryl group in the substituent R ₁ in the formula (1) include a monocyclic or condensed polycyclic aryl group having 4 to 18 carbon atoms which may contain a hetero atom, and specific examples thereof include a phenyl group and 1-naphthyl. Group, 2-naphthyl group, 9-anthryl group, 9-phenanthryl group, 2-furyl group, 2-thienyl group, 2-pyrrolyl group, 6-indolyl group, 2-benzofuryl group, 2-benzothienyl group, 4- Quinolinyl group, 4-isoquinolyl group, 2-carbazolyl group, 3-carbazolyl group, 4-carbazolyl group, 9-acridinyl group, 3-phenothiazinyl group, 2-phenoxathiinyl group, 3-phenoxazinyl group, 3-thianthenyl Although a group etc. can be mentioned, it is not limited to these. Further, these aryl groups may be bonded to an oxygen atom at a substitution position other than those described above, and these are also included in the category of the substituent represented by —OR ₁ in the present invention.

The alkyl group and aryl group represented by R ₁ described above may be further substituted with other substituents, such as a hydroxyl group, a mercapto group, a cyano group, a nitro group, Examples thereof include a halogen atom, an alkyl group, an aryl group, an acyl group, an alkoxyl group, an aryloxy group, an acyloxy group, an alkylthio group, and an arylthio group.

  Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom. Examples of the alkyl group include linear, branched, monocyclic or condensed polycyclic alkyl groups having 1 to 18 carbon atoms. Specific examples include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, Hexyl, heptyl, octyl, nonyl, decyl, dodecyl, octadecyl, isopropyl, isobutyl, isopentyl, sec-butyl, t-butyl, sec-pentyl, t-pentyl, Examples include t-octyl group, neopentyl group, cyclopropyl group, cyclobutyl, cyclopentyl group, cyclohexyl group, adamantyl group, norbornyl group, boronyl group, 4-decylcyclohexyl group and the like.

  Examples of the aryl group include a monocyclic or condensed polycyclic aryl group having 4 to 18 carbon atoms which may contain a hetero atom, and specific examples include a phenyl group, a 1-naphthyl group, a 2-naphthyl group, and a 9-anthryl group. 9-phenanthryl group, 1-pyrenyl group, 5-naphthacenyl group, 1-indenyl group, 1-acenaphthyl group, 9-fluorenyl group, 2-furanyl group, 2-thienyl group, 2-indolyl group, 3-indolyl group 2-benzofuryl group, 2-benzothienyl group, 2-carbazolyl group, 3-carbazolyl group, 4-carbazolyl group, 9-acridinyl group and the like.

  As the acyl group, a hydrogen atom, a carbonyl group to which a linear, branched, monocyclic or condensed polycyclic aliphatic group having 1 to 18 carbon atoms is bonded, or a carbon atom which may contain a hetero atom is 4 carbon atoms. To 18 monocyclic or condensed polycyclic aromatic carbonyl groups, which may have an unsaturated bond in the structure. Specific examples thereof include formyl group, acetyl group, propionyl group, Butyryl group, isobutyryl group, valeryl group, isovaleryl group, pivaloyl group, lauroyl group, myristoyl group, palmitoyl group, stearoyl group, cyclopentylcarbonyl group, cyclohexylcarbonyl group, acryloyl group, methacryloyl group, crotonoyl group, isocrotonoyl group, oleoyl group Benzoyl group, 1-naphthoyl group, 2-naphthoyl group, syn Moil group, 3-furoyl, 2-thenoyl group, nicotinoyl group, isonicotinoyl group, 9-Ansuroiru group, and the like 5 Nafutasenoiru group.

  Examples of the alkoxyl group include linear, branched, monocyclic or condensed polycyclic alkoxyl groups having 1 to 18 carbon atoms, and specific examples include methoxy group, ethoxy group, propoxy group, butoxy group, pentyloxy. Group, hexyloxy group, heptyloxy group, octyloxy group, nonyloxy group, decyloxy group, dodecyloxy group, octadecyloxy group, isopropoxy group, isobutoxy group, isopentyloxy group, sec-butoxy group, t-butoxy group, sec-pentyloxy group, t-pentyloxy group, t-octyloxy group, neopentyloxy group, cyclopropyloxy group, cyclobutyloxy group, cyclopentyloxy group, cyclohexyloxy group, adamantyloxy group, norbornyloxy group , Boronyloxy group, 4-decyl Black hexyloxy group, 2-tetrahydrofuranyl group, 2-tetrahydrofuranyl group, and the like.

  Examples of the aryloxy group include monocyclic or condensed polycyclic aryloxy groups having 4 to 18 carbon atoms that may contain a hetero atom. Specific examples include a phenoxy group, a 1-naphthyloxy group, a 2-naphthyloxy group, 9 -Anthryloxy group, 9-phenanthryloxy group, 1-pyrenyloxy group, 5-naphthacenyloxy group, 1-indenyloxy group, 2-azurenyloxy group, 1-acenaphthyloxy group, 9-fluore Nyloxy group, 2-furanyloxy group, 2-thienyloxy group, 2-indolyloxy group, 3-indolyloxy group, 2-benzofuryloxy group, 2-benzothienyloxy group, 2-carbazolyloxy group , 3-carbazolyloxy group, 4-carbazolyloxy group, 9-acridinyloxy group and the like.

  The acyloxy group is a hydrogen atom or a carbonyloxy group to which a linear, branched, monocyclic or condensed polycyclic aliphatic group having 1 to 18 carbon atoms is bonded, or a carbon number which may contain a hetero atom. Examples include a carbonyloxy group having 4 to 18 monocyclic or condensed polycyclic aromatics bonded thereto, and specific examples include an acetoxy group, a propionyloxy group, a butyryloxy group, an isobutyryloxy group, a valeryloxy group, and an isovaleryloxy group. Group, pivaloyloxy group, lauroyloxy group, myristoyloxy group, palmitoyloxy group, stearoyloxy group, cyclopentylcarbonyloxy group, cyclohexylcarbonyloxy group, acryloyloxy group, methacryloyloxy group, crotonoyloxy group, isocrotonoyloxy group, Oleo oil Xyl group, benzoyloxy group, 1-naphthoyloxy group, 2-naphthoyloxy group, cinnamoyloxy group, 3-furoyloxy group, 2-thenoyloxy group, nicotinoyloxy group, isonicotinoyloxy group, 9-anth Examples include a royloxy group and a 5-naphthacenoyloxy group.

  Examples of the alkylthio group include linear, branched, monocyclic or condensed polycyclic alkylthio groups having 1 to 18 carbon atoms. Specific examples include a methylthio group, an ethylthio group, a propylthio group, a butylthio group, and a pentylthio group. Hexylthio group, octylthio group, decylthio group, dodecylthio group, octadecylthio group and the like.

  Examples of the arylthio group include a monocyclic or condensed polycyclic arylthio group having 4 to 18 carbon atoms which may contain a hetero atom, and specific examples include a phenylthio group, a 1-naphthylthio group, a 2-naphthylthio group, and a 9-anthrylthio group. Group, 9-phenanthrylthio group, 2-furylthio group, 2-thienylthio group, 2-pyrrolylthio group, 6-indolylthio group, 2-benzofurylthio group, 2-benzothienylthio group, 2-carbazolylthio group, 3 -A carbazolylthio group, a 4-carbazolylthio group, etc. can be mentioned, However, It is not limited to these.

Among the above substituents, R ₁ is preferably an alkyl group from the viewpoint of the difficulty of synthesis and the sensitivity as an acid generator, and particularly a linear, cyclic or branched chain having 1 to 8 carbon atoms. Alkyl groups are particularly preferred.

Substituents R ₂ and R ₃ definitive alkyl group in the formula (1), is a aryl group include an alkyl group in the substituents R _1, the aryl group and the same substituents, the alkenyl group, Examples thereof include linear, branched, monocyclic or condensed polycyclic alkenyl groups having 1 to 18 carbon atoms, which may have a plurality of carbon-carbon double bonds in the structure. Are vinyl, 1-propenyl, allyl, 2-butenyl, 3-butenyl, isopropenyl, isobutenyl, 1-pentenyl, 2-pentenyl, 3-pentenyl, 4-pentenyl, 1-hexenyl group, 2-hexenyl group, 3-hexenyl group, 4-hexenyl group, 5-hexenyl group, cyclopentenyl group, cyclohexenyl group, 1,3-butadienyl group, cyclohexadienyl Group, and the like cyclopentadienyl group. However, it is not limited to these.

The substituent R ₂ may be bonded to R ₃ via a divalent organic residue to form a ring structure. The divalent organic residue here is an alkylene group which may have a substituent having 1 to 4 carbon atoms, an arylene group which may have a substituent, an arylalkylene group, or -C = C-, —O—, —S—, —NH—, —SO ₂ —, —CO—, —COO—, —OCOO—, —CONH—, —SO ₂ —O—, and a combination thereof. An alkylene group which may have a substituent is meant.

Of the above substituents, R ₂ and R ₃ are preferably alkyl groups from the viewpoint of difficulty in synthesis, cost of obtaining raw materials, and difficulty, and in particular, straight-chain, cyclic, and branched having 1 to 8 carbon atoms. A chain alkyl group is particularly preferred.

Next, the anion part [BY _m Z _n ] ⁻ in the formula (1) will be described.
Wherein Y a fluorine atom or a chlorine atom, Z is a fluorine atom, a cyano group, two or more substituted phenyl group with a group selected from nitro and a group consisting of a trifluoromethyl group, m is 0 to 3 the integer, n represents each of 1 4 integer, that m + n = 4.

  As the substituent Z in the formula (1), 3,5-difluorophenyl group, 2,4,6-trifluorophenyl group, 2,3,4,6-tetrafluorophenyl group, pentafluorophenyl group, 2, 4-bis (trifluoromethyl) phenyl group, 3,5-bis (trifluoromethyl) phenyl group, 2,4,6-trifluoro-3,5-bis (trifluoromethyl) phenyl group, 3,5- Dinitrophenyl group, 2,4,6-trifluoro-3,5-dinitrophenyl group, 2,4-dicyanophenyl group, 4-cyano-3,5-dinitrophenyl group, 4-cyano-2,6-bis Examples thereof include (trifluoromethyl) phenyl group, but are not limited thereto.

Specific examples of the structure of the borate anion represented by [BY _m Z _n ] ⁻ in formula (1) include pentafluorophenyl trifluoroborate, 3,5-bis (trifluoromethyl) phenyl trifluoroborate, and bis. (Pentafluorophenyl) difluoroborate, bis [3,5-bis (trifluoromethyl) phenyl] difluoroborate, tris (pentafluorophenyl) fluoroborate, tris [3,5-bis (trifluoromethyl) phenyl] fluoroborate , Tetrakis (pentafluorophenyl) borate, tetrakis [3,5-bis (trifluoromethyl) phenyl] borate and the like.

Of these, tetrakis (pentafluorophenyl) borate and tetrakis [3,5-bis (trifluoromethyl) phenyl] borate are particularly preferred as the borate anion in formula (1).

Cationic photopolymerization initiator which is expressed by formula (1) in the present invention (A) (the energy-sensitive Sensan generator) is located in a per se known compound ing a combination of the illustrated sulfonium cation and a borate anion with the , difficulty of synthesis, sensitivity as an acid generator, but is a surface or found suitable Yichun selection cost and difficulty of availability of raw materials, more preferred are compounds represented by the formula (2).

Next, the epoxy resin (B) will be described.
The epoxy resin (B) in the present invention is not particularly limited as long as it is an epoxy resin having two or more epoxy groups in one molecule. When there are less than two epoxy groups in one molecule, the chemical resistance, heat resistance, etc. of the cured product are significantly lowered, and there is a possibility that it cannot be used as a permanent film. Specific examples include novolaks obtained by reacting phenols (phenol, alkyl-substituted phenol, naphthol, alkyl-substituted naphthol, dihydroxybenzene, dihydroxynaphthalene, etc.) with formaldehyde in the presence of an acidic catalyst, epichlorohydrin and / or methyl epichlorohydrin. Examples thereof include a novolak type epoxy resin obtained by reacting with such a halohydrin, an epoxy compound obtained by an oxidation reaction of a compound having an olefin, and the like.

The epoxy equivalent of these epoxy resins (B) is 150-500 g / eq. Is preferable, and if it is smaller than this range, the curing shrinkage is large, and it is not preferable in that the cured product tends to warp or crack. On the other hand, when it is larger than this range, the crosslinking density is decreased, and the strength, chemical resistance, heat resistance and crack resistance of the cured film are unfavorably deteriorated. The epoxy equivalent referred to in the present invention is an epoxy equivalent measured by a method according to JIS K7236.
Further, when the softening point is low, mask sticking is likely to occur during patterning, and further, softening at room temperature is also preferable when used as a dry film resist. On the other hand, when the softening point of the epoxy resin (B) is high, it is not preferable since the softening is difficult when laminating the dry film resist to the substrate and the bonding property to the substrate is deteriorated. For the above reasons, the preferred softening point of the polyfunctional epoxy resin is 40 to 120 ° C, more preferably 50 to 100 ° C. The softening point as used in the field of this invention is the softening point measured by the method based on JISK7234.
Thus, in the photosensitive resin composition of this invention, the epoxy resin whose softening point is 40 degreeC or more and 120 degrees C or less and whose epoxy equivalent is 150-500 / eq is preferable. Specific examples of the epoxy resin (B) satisfying the above range include EOCN-102S, EOCN-103S, EOCN-104S, EOCN-1020, EOCN-4400H, EPPN-201, BREN-S, NER-7604, NER-7403. , NER-1302, NER-7516, NC-3000H (all manufactured by Nippon Kayaku Co., Ltd.), Epicoat 157S70 (manufactured by Japan Epoxy Resin Co., Ltd.), EHPE3150 (manufactured by Daicel Corporation), and the like.

Of these epoxy resins (B), the epoxy resins represented by the formulas (B-1), (B-2), (B-3), (B-4) and (B-5) are preferable. As specific examples of the epoxy resin represented by the formula (B-1), Epicoat 157 (manufactured by JER: epoxy equivalent 180-250 g / eq., Softening point 80-90 ° C.), EPON SU-8 (resolution) -Performance Products make: epoxy equivalent 195-230 g / eq., Softening point 80-90 degreeC) etc. are mentioned. Specific examples of the epoxy resin represented by the formula (B-2) include NC-3000 (manufactured by Nippon Kayaku Co., Ltd .: epoxy equivalent of 270 to 300 g / eq., Softening point of 55 to 75 ° C.). Specific examples of the epoxy resin represented by the formula (B-3) include NER-7604, NER-7403, NER-1302, and NER-7516 (Nippon Kayaku Co., Ltd .: epoxy equivalent: 200 to 500 g / eq). , Softening point 55 to 75 ° C.). Specific examples of the epoxy resin represented by the formula (B-4) include EOCN-1020 (manufactured by Nippon Kayaku Co., Ltd .: epoxy equivalent 190-210 g / eq., Softening point 55-85 ° C.). Specific examples of the epoxy resin represented by the formula (B-5) include NC-6300 (manufactured by Nippon Kayaku Co., Ltd .: epoxy equivalent 230 to 235 g / eq., Softening point 70 to 72 ° C.).
The “epoxy resin represented by the formula (B-1)” means an epoxy resin mainly composed of the epoxy resin represented by the formula (B-1). The case where the subcomponent produced when manufacturing, the high molecular weight body of the epoxy resin represented by Formula (B-1), etc. are contained.

  In the present invention, the combination of the cationic photopolymerization initiator (A) and the epoxy resin (B) having two or more epoxy groups in one molecule can be arbitrarily selected. A combination of the cationic photopolymerization initiator (A-1) and the epoxy resins (B-1) to (B-5) represented by the above formulas (3) to (7) is preferable.

It will be described blending ratio of each component in the photosensitive resin composition of the present invention in the following.
In the photosensitive resin composition of the present invention, a photocationic polymerization initiator (A) (hereinafter sometimes simply referred to as “component (A) ”) and an epoxy resin having two or more epoxy groups in one molecule (B ) (Hereinafter sometimes referred to simply as “component (B) ” ) is 100% by mass, the component (B) 85-99. It mix | blends in the ratio of 9 weight%. Since the photocationic polymerization initiator (A) used in the photosensitive resin composition of the present invention has a high molar extinction coefficient at a wavelength of 300 to 380 nm, an appropriate blending ratio depending on the film thickness when used as the photosensitive resin composition. Need to be adjusted.

  To the photosensitive resin composition of the present invention, a miscible reactive epoxy monomer (C) (hereinafter sometimes simply referred to as “C component”) may be added in order to further improve pattern performance. As the reactive epoxy monomer, a glycidyl ether compound can be used. For example, diethylene glycol diglycidyl ether, hexanediol diglycidyl ether, dimethylolpropane diglycidyl ether, polypropylene glycol diglycidyl ether (manufactured by Adeka Corporation, ED506), trimethylol. Examples include propane triglycidyl ether (manufactured by Adeka Corporation, ED505), trimethylolpropane triglycidyl ether (low chlorine type, manufactured by Nagase ChemteX Corporation, EX321L), pentaerythritol tetraglycidyl ether, and the like. Furthermore, since these epoxy monomers generally have a high chlorine content, it is preferable to use those of low chlorine type that have undergone a low chlorine production method or purification step. These can be used alone or in admixture of two or more. The reactive epoxy monomer (C) component is used for the purpose of improving the reactivity of the resist and the physical properties of the cured film, but the reactive epoxy monomer component is often in liquid form and is photosensitive when the component is liquid. If it is added in an amount of more than 20% by mass based on the total amount of the resin composition, it is unsuitable because mask sticking easily occurs due to stickiness of the film after removal of the solvent. From this point, when the monomer component is blended, the blending ratio is 10 with respect to the solid content when the sum of the components (A), (B) and (C) is the solid content of the resist. The mass is preferably at most 7%, particularly preferably at most 7% by mass.

  A solvent (D) can be used to lower the viscosity of the photosensitive resin composition of the present invention and improve the coating properties. As the solvent, organic solvents that are usually used in inks, paints, and the like, and any solvent that can dissolve each component can be used. Examples of such organic solvents include ketones such as acetone, ethyl methyl ketone, cyclohexanone and cyclopentanone, aromatic hydrocarbons such as toluene, xylene and tetramethylbenzene, dipropylene glycol dimethyl ether and dipropylene glycol diethyl ether. Glycol ethers, ethyl acetate, butyl acetate, butyl cellosolve acetate, carbitol acetate, esters such as propylene glycol monomethyl ether acetate and γ-butyrolactone, alcohols such as methanol, ethanol, ceresolve and methyl ceresolve, octane and decane, etc. Examples thereof include petroleum solvents such as aliphatic hydrocarbons, petroleum ether, petroleum naphtha, hydrogenated petroleum naphtha, and solvent naphtha.

  These solvents can be used alone or in admixture of two or more. The solvent component is added for the purpose of adjusting the film thickness and applicability when applied to the base material, in order to properly maintain the solubility of the main component, the volatility of the component, the liquid viscosity of the composition, etc. The amount used is preferably 95% by mass or less, and particularly preferably 10 to 90% by mass in the photosensitive resin composition.

  In the photosensitive resin composition of the present invention, a miscible adhesion imparting agent may be used for the purpose of further improving the adhesion of the composition to the substrate. As the adhesion-imparting agent, a coupling agent such as a silane coupling agent or a titanium coupling agent can be used, and a silane coupling agent is preferable.

Examples of the silane coupling agent include 3-chloropropyltrimethoxysilane, vinyltrichlorosilane, vinyltriethoxysilane, vinyltrimethoxysilane, vinyl tris (2-methoxyethoxy) silane, 3-methacryloxypropyltrimethoxysilane, 2 -(3,4-epoxycyclohexyl) ethyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N-2- (aminoethyl) -3 -Aminopropyltrimethoxysilane, 3-ureidopropyltriethoxysilane, etc. are mentioned. These adhesiveness imparting agents can be used alone or in combination of two or more.
Since the adhesion-imparting agent is non-reactive with the main component, components other than those that act at the substrate interface exist as residual components after curing, and if used in a large amount, adverse effects such as deterioration of physical properties will occur. Depending on the base material, it can be used in a range that does not adversely affect the effect even in a small amount, and its use ratio is preferably 15% by mass or less, particularly preferably based on the photosensitive resin composition. Is 5% by mass or less.

  In the photosensitive resin composition of the present invention, a sensitizer may be further used for absorbing ultraviolet light and supplying the absorbed light energy to the photocationic polymerization initiator. As the sensitizer, for example, an anthracene compound having an alkoxy group at the 9-position and the 10-position (9,10-dialkoxyanthracene derivative) is preferable. Examples of the alkoxy group include C1-C4 alkoxy groups such as a methoxy group, an ethoxy group, a propoxy group, and a butoxy group. The 9,10-dialkoxyanthracene derivative may further have a substituent. Examples of the substituent include halogen atoms such as fluorine atom, chlorine atom, bromine atom and iodine atom, C1-C4 alkyl group such as methyl group, ethyl group and propyl group, sulfonic acid alkyl ester group, and carboxylic acid alkyl ester group. Etc. Examples of the alkyl in the sulfonic acid alkyl ester group and the carboxylic acid alkyl ester include C1-C4 alkyl such as methyl, ethyl, and propyl. The substitution position of these substituents is preferably the 2-position.

  Examples of the 9,10-dialkoxyanthracene derivative include 9,10-dimethoxyanthracene, 9,10-diethoxyanthracene, 9,10-dipropoxyanthracene, 9,10-dibutoxyanthracene, and 9,10-dimethoxy-2. -Ethylanthracene, 9,10-diethoxy-2-ethylanthracene, 9,10-dipropoxy-2-ethylanthracene, 9,10-dimethoxy-2-chloroanthracene, 9,10-dimethoxyanthracene-2-sulfonic acid methyl ester 9,10-diethoxyanthracene-2-sulfonic acid methyl ester, 9,10-dimethoxyanthracene-2-carboxylic acid methyl ester, and the like. These can be used alone or in admixture of two or more. Since the sensitizer component exerts its effect in a small amount, its use ratio is preferably 3% by mass or less, particularly preferably 1% by mass or less, relative to the photocationic polymerization initiator (A) component.

  In the present invention, when it is necessary to reduce the adverse effects of ions derived from the photocationic polymerization initiator (A), trismethoxyaluminum, trisethoxyaluminum, trisisopropoxyaluminum, isopropoxydiethoxyaluminum, trisbutoxyaluminum, etc. Alkoxyaluminum, Trisphenoxyaluminum and Trisparamethylphenoxyaluminum, etc. Phenoxyaluminum, Trisacetoxyaluminum, Trisstearatoaluminum, Trisbutyratoaluminum, Trispropionatoaluminum, Trisacetylacetonatoaluminum, Tristrifluoroacetylacetonatoaluminum , Trisethylacetoacetoaluminum, diacetylacetonatodipivaloylmethanatoa Miniumu and diisopropoxy (ethylacetoacetato) may be added to the ion catcher, such as aluminum and organic aluminum compounds, these ingredients may be used alone or in combination of two or more. Moreover, the compounding quantity is 10 mass% or less with respect to this solid content, when the sum total of (A) component, (B) component, and (C) component is made into solid content of a resist.

  Furthermore, in this invention, various additives, such as a thermoplastic resin, a coloring agent, a thickener, an antifoamer, a leveling agent, can be used as needed. Examples of the thermoplastic resin include polyethersulfone, polystyrene, and polycarbonate. Examples of the colorant include phthalocyanine blue, phthalocyanine green, iodin green, crystal violet, titanium oxide, carbon black, and naphthalene black. Examples of the thickener include olben, benton, and montmorillonite. Examples of the antifoaming agent include antifoaming agents such as silicone-based, fluorine-based, and polymer-based, and these additives are used. In this case, the amount used is, for example, about 0.1 to 30% by mass in the photosensitive resin composition of the present invention, but may be appropriately increased or decreased depending on the purpose of use.

  Further, in the present invention, for example, an inorganic filler such as barium sulfate, barium titanate, silicon oxide, amorphous silica, talc, clay, magnesium carbonate, calcium carbonate, aluminum oxide, aluminum hydroxide, mica powder or the like is used. The blending ratio is 0 to 60% by mass in the composition.

The photosensitive resin composition of the present invention is preferably one in which the respective components are blended in the proportions shown in Table 1 below . If necessary, the adhesion imparting agent, the sensitizer, the ion catcher, and the thermoplastic resin. Coloring agents, thickeners, antifoaming agents, leveling agents and inorganic fillers may be added. The photosensitive resin composition of the present invention, mixing the above components in a conventional manner, can be adjusted simply by stirring, optionally dissolver, a homogenizer, dispersion using a dispersing machine such as a three-roll mill, and mixed Also good. Furthermore, following mixing, further mesh may be facilities filtered using a membrane filter.

Table 1
Ingredient name Mass Photocationic polymerization initiator (A) 0.1-15
Epoxy resin (B) 85-99.9
Reactive epoxy monomer (C) 1-10
Solvent (D) 5.8-2090

  The photosensitive resin composition of the present invention is preferably used in liquid form. In order to use the photosensitive resin composition of the present invention, for example, a metal substrate such as silicon, aluminum or copper, a ceramic substrate such as lithium tantalate, glass, silicon oxide or silicon nitride, a substrate such as polyimide or polyethylene terephthalate After coating with a spin coater or the like with a thickness of 0.1 to 1000 μm on top and heat-treating at 60 to 130 ° C. for about 5 to 60 minutes to remove the solvent and forming a photosensitive resin composition layer, a predetermined pattern is formed. After a heat treatment is performed at 50 to 130 ° C. for about 1 to 50 minutes, the unexposed portion is exposed to a developer at room temperature to 50 ° C. for about 1 to 180 minutes. Development is performed to form a pattern, and then heat treatment is performed at 130 to 200 ° C. to obtain a permanent protective film satisfying various characteristics. As the developer, for example, an organic solvent such as γ-butyrolactone, triethylene glycol dimethyl ether, propylene glycol monomethyl ether acetate, or a mixed solution of the organic solvent and water can be used. For development, a paddle type, spray type, shower type, or other developing device may be used, and ultrasonic irradiation may be performed as necessary. In addition, aluminum is mentioned as a preferable metal substrate in using the photosensitive resin composition of this invention.

  The resin composition of the present invention is applied to the base film using a roll coater, die coater, knife coater, bar coater, gravure coater, etc., and then dried in a drying oven set at 45 to 100 ° C. A dry film resist can be obtained by removing a predetermined amount of the solvent and, if necessary, laminating a cover film or the like. At this time, the thickness of the resist on the base film is adjusted to 2 to 100 μm. As a base film and a cover film, films, such as polyester, a polypropylene, polyethylene, TAC, a polyimide, are used, for example. As these films, a film subjected to a release treatment with a silicone-type release treatment agent, a non-silicone-type release treatment agent, or the like may be used as necessary. In order to use this dry film resist, for example, the cover film is peeled off, transferred to a substrate at a temperature of 40 to 100 ° C. and a pressure of 0.05 to 2 MPa by a hand roll, a laminator, etc., and the photosensitive resin composition described above Similarly to the above, exposure, post-exposure baking, development, and heat treatment may be performed.

  If the photosensitive resin composition is supplied as a film as described above, the steps of coating on the support and drying can be omitted, and the photosensitive resin composition of the present invention can be used more simply. Pattern formation is possible.

When used as a MEMS and a semiconductor package, it can be used by coating with the photosensitive resin composition of the present invention or making a hollow structure. As a substrate for MEMS and semiconductor packages, a thin metal film of aluminum, gold, copper, chromium, titanium or the like is formed on a silicon wafer having various shapes by sputtering or vapor deposition to a thickness of 10 to 5000 mm, and the etching is used to form the thin film. A substrate or the like obtained by finely processing a metal is used. Depending on the case, silicon oxide or silicon nitride may be formed as an inorganic protective film with a film thickness of 10 to 10,000 mm. It is then necessary to make a coating or hollow structure on the substrate in order to make or install a MEMS or semiconductor device and to shield the device from the outside air. When covering with the photosensitive resin composition of this invention, it can carry out by the method of the said description. In the case of producing a hollow structure, a partition wall is formed on the substrate by the above-described method, and further, a dry film is laminated thereon and patterned so as to become a lid on the partition wall by the above-described method. Thus, a hollow package structure can be produced. Moreover, the MEMS and semiconductor package component which satisfy | fill various characteristics are obtained by heat-processing for 10 to 120 minutes at 130-200 degreeC as needed after preparation.
Note that the “package” is a sealing method used to block the intrusion of gas or liquid in the outside air in order to maintain the stability of the substrate, wiring, elements, and the like. The package described in the present invention is performed in order to prevent deterioration of a package having a driving unit such as a MEMS, a hollow package for packaging a vibrator such as a SAW device, a semiconductor substrate, a printed wiring board, wiring, or the like. It represents surface protection, resin sealing, and the like.

  The photosensitive resin composition of the present invention has good image resolution, thermal stability, chemical resistance and solvent solubility, is highly sensitive, and does not decrease adhesion to the substrate after the pressure cooker test (PCT). Since there are features, for example, MEMS (micro electro mechanical system) parts, micro machine parts, micro fluid parts, μ-TAS (micro total analysis system) parts, inkjet printer parts, micro reactor parts, conductive layers, LIGA parts, Used for the production of molds and stamps for micro injection molding and hot embossing, screens or stencils for micro printing applications, MEMS and semiconductor package parts, BioMEMS and biophotonic devices, and printed wiring boards. Especially, it is useful in MEMS and semiconductor package parts.

  EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, these Examples are only the illustrations for demonstrating this invention suitably, and do not limit this invention at all.

Examples 1 to 5 and Comparative Example 1
(Preparation of photosensitive resin composition)
According to the blending amount shown in Table 2 (unit is part by mass), the polyfunctional epoxy resin, the photocationic polymerization initiator, and other components were stirred and mixed in a flask with a stirrer at 60 ° C. for 1 hour, for the present invention and comparative purposes. A photosensitive resin composition was obtained.

(Patterning of photosensitive resin composition)
After applying the photosensitive resin compositions of Examples 1-5 and Comparative Example 1 by a spin coater on a silicon wafer, dried, "film thickness after coating" in thickness (Table 2 shown in Table 2 Coating The photosensitive resin composition layer having a thickness after drying was obtained. This photosensitive resin composition layer was pre-baked on a hot plate at 65 ° C. for 5 minutes and at 95 ° C. for 15 minutes. Thereafter, pattern exposure (soft contact, i-line) is performed using an i-line exposure apparatus (mask aligner: manufactured by USHIO INC.), And then post-exposure baking (hereinafter referred to as “PEB”) at 95 ° C. for 6 minutes using a hot plate. after the make) was Tsu line, cured 5 minutes between development at 23 ° C. by immersion method using a propylene glycol monomethyl ether acetate (hereinafter referred to as "PGMEA") with a line Ukoto, on a substrate (silicon wafer) A resin pattern was obtained.

(Sensitivity evaluation of photosensitive resin composition)
In the pattern exposure, the exposure amount with the best mask transfer accuracy was set as the optimal exposure amount, and the sensitivity of each photosensitive resin composition was evaluated. The smaller the optimum exposure value, the higher the sensitivity. The results are shown in Table 2 below.

(Resolution evaluation of photosensitive resin composition)
Resolution: In the pattern exposure, using the photomask of 1, 5, 10 and 20 μm line and space, measure the finest pattern width closely attached to the substrate in the resist pattern resolved without residue did. The results are shown in Table 2 below.

(Evaluation of PCT resistance of photosensitive resin composition)
A 1000 ア ル ミ ニ ウ ム aluminum thin film was formed on a silicon wafer by sputtering, and the photosensitive resin compositions obtained in Examples 1 to 5 and Comparative Example 1 were subjected to the same patterning using the substrate. . Each obtained test piece was hard-baked at 150 ° C. for 30 minutes in a warm air convection oven. Thereafter, each test piece was placed in a HAST chamber (manufactured by Espec Corp.), kept at 121 ° C., 100% RH, 2 atm, and maintained at constant temperature and humidity for 20 hours (PCT). PCT resistance was evaluated by measuring the adhesive force of the pattern schematically shown in FIG. The contact force was applied from the side surface of the pattern using a shear tool, and the shear strength at the time when the pattern was peeled from the substrate was defined as the contact force.
Evaluation criteria ○: Adhesion force is 50 gf or more Δ: Adhesion force is 5 g or more and less than 50 g ×: Less than 5 gf (below measurement limit)

In addition, (A-1)-(F) in Table (2) shows the following, respectively.
(A-1): Photocationic polymerization initiator represented by the formula (2) (trade name TAG-382, manufactured by Toyo Ink Manufacturing Co., Ltd.)
(B-1): Epoxy resin represented by the above formula (3) (trade name EPON SU-8, manufactured by Resolution Performance Products)
(B-2): Epoxy resin represented by the formula (4) (trade name: NC-3000H, manufactured by Nippon Kayaku Co., Ltd.)
(B-3): Epoxy resin represented by formula (5) (trade name: NER-7604, manufactured by Nippon Kayaku Co., Ltd.)
(B-4): Epoxy resin represented by formula (6) (trade name EOCN-1020, manufactured by Nippon Kayaku Co., Ltd.)
(B-5): Epoxy resin represented by the formula (7) (trade name NC-6300, manufactured by Nippon Kayaku Co., Ltd.)
(PAG-1): Photocationic polymerization initiator (diphenyl [4- (phenylthio) phenyl] sulfonium = hexafluoroantimonate, trade name CPI-101A, manufactured by San Apro, 50% propylene carbonate solution)
(C-1): Reactive epoxy monomer (trade name ED-506, manufactured by Adeka)
(C-2): Reactive epoxy monomer (trade name EX-321L, manufactured by Nagase ChemteX Corporation)
(D): Solvent Cyclopentanone (E): Fluorine-based leveling agent (trade name: Megafac F-470, manufactured by DIC)
(F): Silane coupling agent (trade name S-510, manufactured by Chisso Corporation)

  As shown in Table 2, the photosensitive resin composition (Examples 1 to 5) of the present invention has higher sensitivity and higher PCT resistance (adhesion to the substrate does not decrease) than Comparative Example 1. understood.

Example 6
(Photosensitive resin composition laminate)
The photosensitive resin composition obtained in Example 1 above was uniformly applied on a polypropylene (PP) film (base film, manufactured by Toray Industries, Inc.) having a film thickness of 15 μm, and then heated at 65 ° C. for 5 minutes by a hot air convection dryer. after drying for 20 minutes between and 80 ° C., it was laminated to a thickness of 38 [mu] m PP film (cover film) on the exposed surface to form a photosensitive resin composition laminated body of 15μm in thickness.

(Patterning of photosensitive resin composition laminate)
80μm by peeling off the cover film of the obtained photosensitive resin composition laminated body by the roll temperature 70 ° C., was laminated on a silicon wafer in air pressure 0.2 MPa, speed of 0.5 m / min, repeating this The photosensitive resin composition layer was obtained. This photosensitive resin composition layer was subjected to pattern exposure (soft contact, i-line) using an i-line exposure apparatus (mask aligner: manufactured by Ushio Inc.). Then after Tsu rows 4 minutes PEB at 95 ° C. with a hot plate to obtain a resin pattern cured on a substrate 4 minutes development at line Ukoto at 23 ° C. by immersion method using PGMEA. Good results were obtained with an optimal exposure of 180 mJ / cm ² and fine wire adhesion of 5 μm.

  The photosensitive resin composition according to the present invention possesses good image resolution, thermal stability, chemical resistance and solvent property, is highly sensitive, and does not deteriorate adhesion to the substrate after the pressure cooker test (PCT). It is useful for forming a resin pattern, and is particularly suitable for resin molding with high dimensional stability and high durability in the field of MEMS parts, MEMS, semiconductor packages, and the like.

Cross-sectional view of test piece used for PCT resistance evaluation

Explanation of symbols

In FIG.
1. A cured product of the laminate of the photosensitive resin composition from which the cover film and the base film are removed,
2. Cured product of photosensitive resin composition,
3. Aluminum thin film (thickness 1000 mm),
4). Silicon wafer (thickness 500 μm),
Respectively.

Claims (8)

Following formula (1)

(In Formula (1), R ₁ represents an alkyl group or an aryl group, R ₂ and R ₃ each independently represents an alkyl group, an aryl group, or an alkenyl group, Y represents a fluorine atom or a chlorine atom, and Z represents a fluorine atom) A phenyl group substituted with two or more groups selected from the group consisting of an atom, a cyano group, a nitro group, and a trifluoromethyl group, m represents an integer of 0 to 3, and n represents an integer of 1 to 4, m + n = 4.)
The photosensitive resin composition for MEMS formed by containing the photocationic polymerization initiator (A) represented by these, and the epoxy resin (B) which has a 2 or more epoxy group in 1 molecule. The photosensitive resin composition for MEMS according to claim 1, wherein the photosensitive resin composition for MEMS is for a package. The cationic photopolymerization initiator (A) is represented by the following formula (2)

The photosensitive resin composition for MEMS of Claim 1 or Claim 2 which is photocationic polymerization initiator (A-1) represented by these. The softening point of the epoxy resin (B) is 40 ° C. or higher and 120 ° C. or lower and the epoxy equivalent is 150 to 500 / eq. The photosensitive resin composition for MEMS according to any one of claims 1 to 3. The epoxy resin (B) has the following formula (3)

(In Formula (3), each R independently represents a glycidyl group or a hydrogen atom . K represents an average value and is a real number in the range of 0 to 30.)
An epoxy resin (B-1) represented by the following formula (4)

(In the formula (4), each R _1, R _2, and R _3, .p represents an alkyl group having independently from one to four hydrogen atoms or carbon atoms in the range of 1 to 30 shows the average value A real number.)
An epoxy resin (B-2) represented by the following formula (5)

(In Formula (5), n and m are average numbers and are independently real numbers in the range of 1 to 30, and R ₄ and R ₅ each independently have a hydrogen atom or 1 to 4 carbon atoms. Represents an alkyl group or trifluoromethyl.)
An epoxy resin (B-3) represented by the following formula (6)

(In Formula (6), n shows an average value and is a real number in the range of 1 to 30.)
An epoxy resin (B-4) represented by the following formula (7)

The photosensitivity for MEMS as described in any one of Claim 1 thru | or 4 which contains the epoxy resin selected from the group which consists of epoxy resin (B-5) represented by these by 1 type (s) or 2 or more types. Resin composition.
Hardened | cured material obtained by hardening | curing the photosensitive resin composition for MEMS as described in any one of Claims 1 thru | or 5. The laminated body which pinched | interposed the photosensitive resin composition for MEMS as described in any one of Claim 1 thru | or 5 with the base material. A cured product obtained by curing the laminate according to claim 7.

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