JP2009265450A - Photosensitive resin composition for microelectronic mechanical system (mems) and cured product of the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a photosensitive resin composition having good image resolution, thermal stability, chemical resistance and solvent solubility, and high sensitivity and no reduction in adhesiveness to a substrate after a pressure cooker test (PCT). <P>SOLUTION: The photosensitive resin composition for an MEMS comprises a photo-cation polymerization initiator (A) comprising a tetrakis pentafluorophenylborate complex, and an epoxy resin (B) having a specific structure including at least two epoxy groups in a single molecule. The epoxy resin (B) has a softening point of 40°C or higher and 120°C and lower and an epoxy equivalent of 150 to 500/eq. <P>COPYRIGHT: (C)2010,JPO&INPIT

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 manufactured by Resolution Performance Products) and CYRACURE UVI-6974 manufactured by Dow Chemical (this photo-resist) A negative-type chemically amplified photoresist composition comprising a cationic polymerization initiator comprising a propylene carbonate solution of aromatic sulfonium hexafluoroantimonate 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)

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 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 as described in (1) or (2) above,
(4) The epoxy resin (B) has the following formula (3)

(In formula (3), each R independently represents a glycidyl group or hydrogen. 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 for MEMS according to any one of (1) to (3) 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,
(5) A cured product obtained by curing the photosensitive resin composition for MEMS according to any one of (1) to (4) above,
(6) A laminate in which the MEMS photosensitive resin composition according to any one of (1) to (4) is sandwiched between substrates,
(7) It is related with the hardened | cured material obtained by hardening | curing the laminated body as described in said clause (6).

  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 comprises a photocationic polymerization initiator (A) represented by the formula (1) and an epoxy resin (B) having two or more epoxy groups in one molecule. It is possible to form a pattern that does not deteriorate the adhesion to the substrate after the pressure cooker test with high sensitivity. 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 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 and heat resistance of the cured product are remarkably lowered, and there is a possibility that it cannot be used as a permanent film. Specific examples of the epoxy resin (B) include novolaks and epichlorohydrin obtained by reacting phenols (phenol, alkyl-substituted phenol, naphthol, alkyl-substituted naphthol, dihydroxybenzene, dihydroxynaphthalene, etc.) with formaldehyde in the presence of an acidic catalyst. And / or a novolak type epoxy resin obtained by reacting with a halohydrin such as methyl epichlorohydrin, 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.

Next, the blending ratio of each component in the photosensitive resin composition of the present invention will be described.
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 (B) having two or more epoxy groups in one molecule ( Hereinafter, when the total amount of the “B component” may be simply 100% by mass, the component (B) is 85 to 99.9% by weight relative to the component (A) 0.1 to 15% by mass. Blended in proportions. 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, it is appropriate depending on the film thickness when the photosensitive resin composition is used. It is necessary to adjust the blending ratio.

  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 thereof 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, vinyltris (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, thioxanthones and anthracene compounds having an alkoxy group at the 9th and 10th positions (9,10-dialkoxyanthracene derivative) are 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.

  Specific examples of thioxanthones include 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, 2-chlorothioxanthone, 2,4-diisopropylthioxanthone and the like, and 2,4-diethylthioxanthone (Nippon Kayaku Co., Ltd.) ), Kayacure DETX) and 2-isopropylthioxanthone are preferred.

  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 may be used alone or in combination of two or more, but the use of 2,4-diethylthioxanthone and 9,10-dimethoxy-2-ethylanthracene is most preferred. Since the sensitizer component exerts its effect in a small amount, its use ratio is preferably 30% by weight or less, particularly preferably 20% by weight 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, such as 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, and examples of the colorant include phthalocyanine blue, phthalocyanine green, iodine 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 blended in the proportions shown in Table 1 below, and if necessary, the adhesion imparting agent, sensitizer, ion catcher, thermoplastic resin, colorant, thickener, defoaming agent. Agents, leveling agents and inorganic fillers may be added. It is only necessary to mix and stir by a usual method, and if necessary, a disperser such as a dissolver, a homogenizer, or a three roll mill may be used for dispersion and mixing. Moreover, after mixing, you may further filter using a mesh, a membrane filter, etc.

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
Sensitizer 0-4.5

  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 of various shapes by sputtering or vapor deposition to a thickness of 10 to 5000 mm, and the etching is used to 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 create 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 a 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 4 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)
Each photosensitive resin composition of Examples 1 to 4 and Comparative Example 1 was applied on a silicon wafer with a spin coater and then dried, and the film thicknesses shown in Table 2 (“film thickness after coating” in Table 2 are applied) A 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 post-exposure baking (hereinafter referred to as “PEB”) at 95 ° C. for 6 minutes using a hot plate. Then, development treatment was performed at 23 ° C. for 5 minutes by a dipping method using propylene glycol monomethyl ether acetate (hereinafter referred to as “PGMEA”) to obtain a cured resin pattern on the substrate (silicon wafer).

(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-mm aluminum thin film was formed on a silicon wafer by sputtering, and the photosensitive resin compositions obtained in Examples 1 to 4 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 30 MPa or higher Δ: Adhesion force is 5 MPa or more and less than 30 MPa ×: Less than 5 MPa (below measurement limit)

In addition, (A-1)-(G) in Table (2) shows the following, respectively.
(A): Photocationic polymerization initiator represented by the above formula (1) (trade name: Rhodosil Photoinitor 2074, manufactured by Rhodia Japan Co., Ltd.)
(B-1): Epoxy resin represented by the 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 the above formula (5) (trade name: NER-7604, manufactured by Nippon Kayaku Co., Ltd.)
(B-4): Epoxy resin represented by the formula (6) (trade name EOCN-1020, manufactured by Nippon Kayaku Co., Ltd.)
(B-5): Epoxy resin represented by 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)
(G): Sensitizer Diethylthioxanthone (2,4-diethylthioxanthone, trade name DETX-S, manufactured by Nippon Kayaku Co., Ltd.)

  As shown in Table 2, the photosensitive resin compositions (Examples 1 to 4) of the present invention have higher sensitivity and higher PCT resistance (adhesion to the substrate does not decrease) than Comparative Example 1. understood.

Example 5
(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 at 80 ° C. for 20 minutes, a PP film (cover film) having a film thickness of 38 μm was laminated on the exposed surface to form a photosensitive resin composition laminate having a film thickness of 15 μm.

(Patterning of photosensitive resin composition laminate)
The cover film of the photosensitive resin composition laminate obtained above was peeled off and laminated on a silicon wafer at a roll temperature of 70 ° C., an air pressure of 0.2 MPa, and a speed of 0.5 m / min, and this was repeated ○ times 80 μm 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.). Thereafter, PEB was performed for 4 minutes at 95 ° C. using a hot plate, and development processing was performed for 4 minutes at 23 ° C. by immersion using PGMEA to obtain a cured resin pattern on the substrate. An optimum exposure amount of 180 mJ / cm ^{2 and a} fine result of 5 μm were obtained.

  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 (7)

Following formula (1)

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 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 claim 1 or 2. The epoxy resin (B) has the following formula (3)

(In formula (3), each R independently represents a glycidyl group or hydrogen. 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 3 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 4. The laminated body which pinched | interposed the photosensitive resin composition for MEMS as described in any one of Claim 1 thru | or 4 with the base material. Hardened | cured material obtained by hardening | curing the laminated body of Claim 6.

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