Negative photosensitive resin composition, cured film, and semiconductor device

Abstract

To provide a negative photosensitive resin composition having low-temperature curability, and a cured film excellent in strength obtained by curing the same.SOLUTION: The negative photosensitive resin composition to be used for a rewiring layer of a semiconductor device contains (A) a phenolic resin, (B) a crosslinking agent, and (C) a photosensitizer. The phenolic resin (A) contains a biphenyl type phenolic resin. The crosslinking agent (B) contains a tetrafunctional urea resin-based crosslinking agent and a bifunctional epoxy resin-based crosslinking agent. A cured product of the negative photosensitive resin composition has a storage modulus at 250°C measured by dynamic mechanical analysis (DMA) of 2,500 MPa or less.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a negative photosensitive resin composition, a cured film made from the cured product thereof, and a semiconductor device including the cured film. [Background technology]

[0002] In the electrical and electronic fields, photosensitive resin compositions containing thermosetting resins are sometimes used to form cured films such as insulating layers. Therefore, photosensitive resin compositions containing thermosetting resins have been investigated. It is known that photosensitive resin compositions containing thermosetting resins can be used to form insulating films in redistribution layers and insulating films in areas other than the redistribution layers.

[0003] As an example, Patent Document 1 describes a photosensitive resin composition containing an alkaline aqueous solution-soluble resin, a crosslinking agent, a photopolymerization initiator, and an epoxy resin (thermosetting resin) represented by a specific general formula. Patent Document 1 also describes that the photosensitivity of this photosensitive resin composition is good. Patent Document 1 also describes that a film formed from this photosensitive resin composition is excellent in flexibility, adhesion, pencil hardness, solvent resistance, acid resistance, heat resistance, gold plating resistance, etc. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-80871 Summary of the Invention [Problem to be solved by the invention]

[0005] As electronic devices become more sophisticated and complex, they are being required to have higher reliability than ever before. Therefore, there is a need to improve the reliability of electronic devices by improving the cured films and the photosensitive resin compositions used to form these cured films. Furthermore, in recent years, there has been a demand for relatively low heating temperatures (e.g., around 200°C) when forming cured films to reduce thermal damage to semiconductor chips.

[0006] The present invention has been made in view of the above-mentioned problems, and the inventors have found that, in a negative-type photosensitive resin composition containing a phenolic resin, a photosensitizer, and the photosensitizer, by using a specific phenolic resin in combination with a specific crosslinking agent, the composition is curable at low temperature and the strength of the cured film obtained by curing the composition is excellent, and have thus completed the present invention. [Means for solving the problem]

[0007] According to the present invention, A negative photosensitive resin composition used in a rewiring layer of a semiconductor device, comprising: The negative photosensitive resin composition comprises: (A) phenolic resin, (B) a cross-linking agent, and (C) a photosensitizer, the phenolic resin (A) includes a biphenyl-type phenolic resin, the crosslinking agent (B) contains a difunctional or higher functional urea resin crosslinking agent and a difunctional or higher functional epoxy resin crosslinking agent, The negative photosensitive resin composition is provided such that, when the negative photosensitive resin composition is cured, the storage modulus at 250°C measured by dynamic mechanical analysis (DMA) is 2500 MPa or less.

[0008] The present invention also provides a cured film obtained by curing the negative photosensitive resin composition.

[0009] Furthermore, according to the present invention, A semiconductor element; a redistribution layer provided on a surface of the semiconductor element, There is provided a semiconductor device, wherein an insulating layer in the rewiring layer is made of the cured film. [Effects of the Invention]

[0010] According to the present invention, there are provided a negative-type photosensitive resin composition having low-temperature curing properties, and a cured film having excellent strength obtained by curing the composition. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a cross-sectional view showing a configuration example of a semiconductor device according to an embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, embodiments of the present invention will be described. In this specification, a numerical range "x to y" represents "not less than x and not more than y," and includes both the lower limit x and the upper limit y. For example, "1 to 5% by mass" means "not less than 1% by mass and not more than 5% by mass." In the following drawings, similar components are given the same reference numerals, and their explanations will be omitted as appropriate. The drawings are schematic and do not correspond to the actual dimensional ratios.

[0013] In the description of groups (atomic groups) in this specification, when a notation does not specify whether the group is substituted or unsubstituted, it encompasses both groups having no substituents and groups having a substituent. For example, the term "alkyl group" encompasses not only alkyl groups having no substituents (unsubstituted alkyl groups) but also alkyl groups having a substituent (substituted alkyl groups).

[0014] [Negative-type photosensitive resin composition] The negative-type photosensitive resin composition of this embodiment is a resin material used to form a rewiring layer of a semiconductor device. The negative-type photosensitive resin composition of this embodiment contains (A) a phenolic resin, (B) a crosslinking agent, and (C) a photosensitizer, The phenolic resin (A) includes a biphenyl-type phenolic resin, The crosslinking agent (B) includes a difunctional or higher functional urea resin crosslinking agent and a difunctional or higher functional epoxy resin crosslinking agent. When the negative photosensitive resin composition of this embodiment is cured, the storage modulus at 250° C. measured by dynamic viscoelasticity measurement (DMA) is 2500 MPa or less.

[0015] In this embodiment, the storage modulus is the storage modulus at 250°C when the cured film obtained by heating the negative photosensitive resin composition at 180°C for 2 hours is subjected to dynamic viscoelasticity measurement under the following conditions. (conditions) Frequency: 1Hz Temperature: 30~300℃ Heating rate: 5°C / min Measurement mode: tension mode

[0016] The present inventors have conducted research to improve the low-temperature curability of negative-type photosensitive resin compositions and the strength of the resulting cured films, and have found that the above-mentioned problems can be solved by configuring a negative-type photosensitive resin composition to contain specific components and configuring a cured film of the negative-type photosensitive resin composition to have a storage modulus within a specific range.

[0017] The storage modulus of the cured film at 250° C. is preferably 2200 MPa or less, and more preferably 2000 MPa or less. The lower limit of the storage modulus of the cured film at 250° C. is, for example, 1400 MPa or more, and preferably 1600 MPa or more.

[0018] The storage modulus of the negative photosensitive resin composition of this embodiment can be adjusted by selecting the components used and the amounts thereof.

[0019] Next, each component will be described in more detail. (Phenol resin (A)) The negative photosensitive resin composition of this embodiment contains a biphenyl-type phenolic resin (a1) as the phenolic resin. From the viewpoint of improving low-temperature curability and the reliability of the cured film, the biphenyl-type phenolic resin (a1) is preferably a phenolic resin having a structural unit represented by the following formula (2):

[0020] [ka]

[0021] In the above formula (2), R 41 , and R 42 are each independently a monovalent substituent selected from the group consisting of a hydroxyl group, a halogen atom, a carboxyl group, a saturated or unsaturated alkyl group having 1 to 20 carbon atoms, an alkyl ether group having 1 to 20 carbon atoms, a saturated or unsaturated alicyclic group having 3 to 20 carbon atoms, or an organic group having an aromatic structure having 6 to 20 carbon atoms, which may be bonded via an ester bond, an ether bond, an amide bond, or a carbonyl bond; r and s are each independently an integer of 0 to 3; Y4 and Z4 are each independently selected from the group consisting of a single bond, or an aliphatic group having 1 to 10 carbon atoms which may have an unsaturated bond, an alicyclic group having 3 to 20 carbon atoms, and an organic group having an aromatic structure having 6 to 20 carbon atoms; and Z4 is bonded to either of the two benzene rings.

[0022] Specifically, the biphenyl-type phenol resin (a1) having the structural unit represented by formula (2) can be obtained using the method described in JP-A-2018-155938.

[0023] The content of the biphenyl-type phenolic resin (a1) in the negative-type photosensitive resin composition of the present embodiment is preferably 5 parts by mass or more, more preferably 10 parts by mass or more, and even more preferably 15 parts by mass or more, based on 100 parts by mass of the total solid content of the negative-type photosensitive resin composition, from the viewpoint of improving curability during low-temperature curing. From the viewpoint of preventing deterioration of toughness, the content of the biphenyl-type phenolic resin (a1) in the negative-type photosensitive resin composition is preferably 70 parts by mass or less, more preferably 60 parts by mass or less, and even more preferably 50 parts by mass or less, based on 100 parts by mass of the total solid content of the negative-type photosensitive resin composition.

[0024] The negative photosensitive resin composition of this embodiment may further contain a phenolic resin (a2) other than the biphenyl-type phenolic resin (a1) described above, from the viewpoint of improving low-temperature curability and the reliability of the cured film. Specific examples of the phenolic resin (a2) include novolac-type phenolic resins such as phenol novolac resin, cresol novolac resin, bisphenol novolac resin, phenol-biphenyl novolac resin, allylated novolac-type phenolic resin, and xylylene novolac-type phenolic resin; reaction products of phenolic compounds with aldehyde compounds, such as novolac-type phenolic resin, resol-type phenolic resin, and cresol novolac resin; and reaction products of phenolic compounds with dimethanol compounds, such as phenol aralkyl resin.

[0025] Among these, the phenolic resin (a2) is preferably a resin having a structure represented by the following formula (1), from the viewpoint of obtaining a resin composition that can be cured at low temperature.

[0026] [ka]

[0027] In the above formula (1), n ​​is preferably 6 or more, more preferably 10 or more, and even more preferably 14 or more, from the viewpoint of improving curability at low temperatures. From the viewpoint of solvent solubility, n is preferably 72 or less, more preferably 54 or less, and even more preferably 36 or less.

[0028] The weight average molecular weight of the biphenyl type phenolic resin (a2) may be, for example, 500 or more, preferably 2000 or more, more preferably 3000 or more, and even more preferably 4000 or more, from the viewpoint of improving curability at low temperatures. The weight average molecular weight of the biphenyl type phenol resin (a2) may be, for example, 50,000 or less, and from the viewpoint of solvent solubility, is preferably 20,000 or less, more preferably 15,000 or less, and even more preferably 10,000 or less.

[0029] When the negative-type photosensitive resin composition contains the biphenyl-type phenol resin (a2), the content thereof is preferably 5 parts by mass or more, more preferably 10 parts by mass or more, and even more preferably 15 parts by mass or more, based on 100 parts by mass of the total solid content of the negative-type photosensitive resin composition, from the viewpoint of improving toughness during low-temperature curing. From the viewpoint of the mechanical properties of the resulting cured film, the content of the biphenyl-type phenolic resin (a2) in the negative-type photosensitive resin composition is preferably 70 parts by mass or less, more preferably 60 parts by mass or less, and even more preferably 50 parts by mass or less, based on 100 parts by mass of the total solid content of the negative-type photosensitive resin composition.

[0030] The negative photosensitive resin composition of this embodiment may contain a thermosetting resin other than a phenolic resin, such as a phenolic resin other than the biphenyl-type phenolic resin described above, a hydroxystyrene resin, a polyamide resin, a polybenzoxazole resin, a polyimide resin, or a cyclic olefin resin.

[0031] Furthermore, the content of the phenolic resin (A) in the negative photosensitive resin composition is preferably 30 parts by mass or more, more preferably 45 parts by mass or more, even more preferably 50 parts by mass or more, and still more preferably 55 parts by mass or more, from the viewpoint of improving the curability at low temperatures and the reliability of the cured film, when the total solid content of the photosensitive resin composition is taken as 100 parts by mass. Furthermore, from the viewpoint of improving chemical resistance and photosensitivity, the content of component (A) in the photosensitive resin composition is preferably 95 parts by mass or less, more preferably 90 parts by mass or less, and even more preferably 85 parts by mass or less, when the total solid content of the photosensitive resin composition is 100 parts by mass. Here, the phenolic resin (A) is the total amount of phenolic resins used in the negative photosensitive resin composition of this embodiment, and the phenolic resin (A) consists of the biphenyl-type phenolic resin (a1) described above and the phenolic resin (a2) used as needed.

[0032] (Crosslinking agent (B)) The negative-type photosensitive resin composition of this embodiment contains a difunctional or higher urea resin-based crosslinking agent (b1) and a difunctional or higher epoxy resin-based crosslinking agent (b2) as the crosslinking agent (B). By containing such crosslinking agents, the negative-type photosensitive resin composition of this embodiment has excellent curing properties at low temperatures.

[0033] Examples of the difunctional or higher functional urea resin-based crosslinking agent (b1) used as a crosslinking agent in the negative photosensitive resin composition of this embodiment include difunctional to tetrafunctional alkoxymethylated glycoluril compounds. The alkoxymethylated glycoluril compound refers to a compound in which the hydrogen atom of the amino group of a glycoluril compound is substituted with an alkoxymethylol group. Specific examples of alkoxymethylated glycolurils include 1,3,4,6-tetrakis(methoxymethyl)glycoluril, 1,3,4,6-tetrakis(butoxymethyl)glycoluril, 1,3,4,6-tetrakis(hydroxymethyl)glycoluril, 1,3-bis(hydroxymethyl)urea, 1,1,3,3-tetrakis(butoxymethyl)urea, 1,1,3,3-tetrakis(methoxymethyl)urea, 1,3-bis(hydroxymethyl)-4,5-dihydroxy-2-imidazolinone, and 1,3-bis(methoxymethyl)-4,5-dimethoxy-2-imidazolinone.

[0034] The bifunctional or higher functional epoxy resin crosslinking agent (b2) used as a crosslinking agent in the negative-tone photosensitive resin composition of this embodiment is preferably a bifunctional phenoxy epoxy resin. Examples of bifunctional phenoxy epoxy resins that can be used include bisphenol A phenoxy resins, bisphenol F phenoxy resins, bisphenol S phenoxy resins, bisphenol acetophenone phenoxy resins, novolac phenoxy resins, biphenyl phenoxy resins, fluorene phenoxy resins, dicyclopentadiene phenoxy resins, norbornene phenoxy resins, naphthalene phenoxy resins, anthracene phenoxy resins, adamantane phenoxy resins, terpene phenoxy resins, and trimethylcyclohexane phenoxy resins. Specific examples of such phenoxy resins include resins JER-1256 and YX-7105 (both manufactured by Mitsubishi Chemical Corporation) and LX-01 (manufactured by Osaka Soda Co., Ltd.).

[0035] The crosslinking agent (B) may contain other crosslinking agents (b3) in addition to the above-mentioned difunctional or higher urea resin crosslinking agent (b1) and difunctional or higher epoxy resin crosslinking agent (b2), as long as the low-temperature curing property of the negative photosensitive resin composition is not impaired. Other examples of the crosslinking agent (b3) include compounds having a methylol group, such as 1,2-benzenedimethanol, 1,3-benzenedimethanol, 1,4-benzenedimethanol (paraxylene glycol), 1,3,5-benzenetrimethanol, 4,4-biphenyldimethanol, 2,6-pyridinedimethanol, 2,6-bis(hydroxymethyl)-p-cresol, and 4,4'-methylenebis(2,6-dialkoxymethylphenol); phenols such as phloroglucide; compounds having an alkoxymethyl group, such as 1,4-bis(methoxymethyl)benzene, 1,3-bis(methoxymethyl)benzene, 4,4'-bis(methoxymethyl)biphenyl, 3,4'-bis(methoxymethyl)biphenyl, 3,3'-bis(methoxymethyl)biphenyl, methyl 2,6-naphthalenedicarboxylate, and 4,4'-methylenebis(2,6-dimethoxymethylphenol); hexamethylolmelamine, hexabutanol, and the like. methylol urea compounds such as methylolbenzoguanamine compounds and dimethylolethyleneurea; alkylated urea resins; cyano compounds such as dicyanoaniline, dicyanophenol, and cyanophenylsulfonic acid; isocyanate compounds such as 1,4-phenylene diisocyanate and 3,3'-dimethyldiphenylmethane-4,4'-diisocyanate; epoxy group-containing compounds such as ethylene glycol diglycidyl ether, bisphenol A diglycidyl ether, triglycidyl isocyanurate, bisphenol A epoxy resin, bisphenol F epoxy resin, naphthalene epoxy resin, biphenyl epoxy resin, and phenol novolac resin epoxy resin; and maleimide compounds such as N,N'-1,3-phenylene dimaleimide and N,N'-methylene dimaleimide.

[0036] The content of the bifunctional or higher urea resin-based crosslinking agent (b1) is preferably 80 parts by mass or more, more preferably 85 parts by mass or more, and even more preferably 90 parts by mass or more, relative to 100 parts by mass of the total solid content of the negative-type photosensitive resin composition, from the viewpoint of improving toughness during low-temperature curing. Furthermore, from the viewpoint of maintaining the thermomechanical properties during low-temperature curing, the content of the tetrafunctional urea resin-based crosslinking agent (b1) in the negative-type photosensitive resin composition is preferably 140 parts by mass or less, more preferably 120 parts by mass or less, and even more preferably 110 parts by mass or less, based on 100 parts by mass of the total solid content of the photosensitive resin composition.

[0037] The content of the bifunctional or higher epoxy resin-based crosslinking agent (b2) is preferably 20 parts by mass or more, more preferably 25 parts by mass or more, and even more preferably 30 parts by mass or more, relative to 100 parts by mass of the total solid content of the negative-type photosensitive resin composition, from the viewpoint of improving toughness during low-temperature curing. Furthermore, from the viewpoint of maintaining the thermomechanical properties during low-temperature curing, the content of the bifunctional or higher epoxy resin crosslinking agent (b2) in the negative photosensitive resin composition is preferably 70 parts by mass or less, more preferably 65 parts by mass or less, and even more preferably 60 parts by mass or less, based on 100 parts by mass of the total solid content of the photosensitive resin composition.

[0038] The content of the crosslinking agent (B) in the negative photosensitive resin composition of the present embodiment is preferably 120 parts by mass or more, more preferably 140 parts by mass or more, and even more preferably 160 parts by mass or more, from the viewpoint of improving toughness during low-temperature curing, relative to 100 parts by mass of the total solid content of the negative photosensitive resin composition. In order to maintain the thermomechanical properties during low-temperature curing, the content of the crosslinking agent (B) in the negative photosensitive resin composition is preferably 250 parts by mass or less, more preferably 220 parts by mass or less, and even more preferably 200 parts by mass or less, based on 100 parts by mass of the total solid content of the negative photosensitive resin composition. Here, the crosslinking agent (B) comprises the above-mentioned tetrafunctional urea resin crosslinking agent (b1) and the difunctional or higher epoxy resin crosslinking agent (b2), as well as other crosslinking agents (b3) that are used as needed.

[0039] (Photosensitizer (C)) The negative photosensitive resin composition of this embodiment contains a photosensitizer (C) from the viewpoint of stably forming a cured film. Specifically, the photosensitizer (C) is an acid generator that generates an acid by absorbing thermal energy or light energy.

[0040] From the viewpoint of improving low-temperature curability and chemical resistance, the photosensitizer (C) preferably contains a sulfonium compound or a salt thereof (c1). The sulfonium compound or salt (c1) is specifically a sulfonium salt having a sulfonium ion as the cation moiety. The anion moiety of the sulfonium compound or salt (c1) is specifically a boride ion, an antimony ion, a phosphorus ion, or a sulfonate ion such as a trifluoromethanesulfonate ion. From the viewpoint of improving the reaction rate at low temperatures, the anion is preferably a boride ion or an antimony ion, and more preferably a boride ion. These anions may have a substituent.

[0041] The sulfonium compound or salt thereof (c1) preferably includes a sulfonium salt represented by the following formula (4):

[0042] [ka]

[0043] In the above general formula (4), R 1 is a hydrogen atom or a monovalent organic group, and from the viewpoint of improving reactivity at low temperatures, is preferably a hydrogen atom or an acyl group, more preferably an acyl group, and even more preferably a CH3C(=O)- group. R 2is a monovalent organic group, and from the viewpoint of improving reactivity at low temperatures, is preferably a linear or branched hydrocarbon group or a benzyl group which may have a substituent, more preferably a benzyl group which may be substituted with an alkyl group having from 1 to 4 carbon atoms or an alkyl group having from 1 to 4 carbon atoms, and even more preferably a methyl group or a benzyl group whose aromatic ring portion may be substituted with a methyl group. R 3 is a monovalent organic group, and from the viewpoint of improving reactivity at low temperatures, is preferably a linear or branched hydrocarbon group, more preferably an alkyl group having 1 to 4 carbon atoms, and more preferably a methyl group.

[0044] Other preferred examples of component (c1) include triphenylsulfonium salts such as triphenylsulfonium trifluoromethanesulfonate.

[0045] When the negative photosensitive resin composition contains the photosensitizer (C), the content thereof is preferably 0.005 parts by mass or more, more preferably 0.01 parts by mass or more, and even more preferably 0.02 parts by mass or more, relative to 100 parts by mass of the total solid content of the negative photosensitive resin composition, from the viewpoint of improving curability at low temperatures. Furthermore, from the viewpoint of suppressing a decrease in reliability, the content of the photosensitizer (C) in the negative photosensitive resin composition is preferably 20 parts by mass or less, more preferably 18 parts by mass or less, and even more preferably 16 parts by mass or less, relative to 100 parts by mass of the total solid content of the photosensitive resin composition.

[0046] (adhesion aid) The negative photosensitive resin composition of this embodiment preferably contains an adhesion aid, which can further improve adhesion to a substrate, for example.

[0047] The adhesion aid is not particularly limited. For example, a silane coupling agent such as an amino group-containing silane coupling agent, an epoxy group-containing silane coupling agent, a (meth)acryloyl group-containing silane coupling agent, a mercapto group-containing silane coupling agent, a vinyl group-containing silane coupling agent, a ureido group-containing silane coupling agent, or a sulfide group-containing silane coupling agent can be used. When a silane coupling agent is used, one type may be used alone, or two or more types may be used in combination.

[0048] Examples of amino group-containing silane coupling agents include bis(2-hydroxyethyl)-3-aminopropyltriethoxysilane, γ-aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, γ-aminopropylmethyldiethoxysilane, γ-aminopropylmethyldimethoxysilane, N-β(aminoethyl)γ-aminopropyltrimethoxysilane, N-β(aminoethyl)γ-aminopropyltriethoxysilane, N-β(aminoethyl)γ-aminopropylmethyldimethoxysilane, N-β(aminoethyl)γ-aminopropylmethyldiethoxysilane, and N-phenyl-γ-aminopropyltrimethoxysilane. Examples of epoxy group-containing silane coupling agents include γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, and γ-glycidylpropyltrimethoxysilane. Examples of the (meth)acryloyl group-containing silane coupling agent include γ-((meth)acryloyloxypropyl)trimethoxysilane, γ-((meth)acryloyloxypropyl)methyldimethoxysilane, and γ-((meth)acryloyloxypropyl)methyldiethoxysilane. An example of a mercapto group-containing silane coupling agent is 3-mercaptopropyltrimethoxysilane. Examples of vinyl group-containing silane coupling agents include vinyltris(β-methoxyethoxy)silane, vinyltriethoxysilane, and vinyltrimethoxysilane. Examples of ureido group-containing silane coupling agents include 3-ureidopropyltriethoxysilane. Examples of sulfide group-containing silane coupling agents include bis(3-(triethoxysilyl)propyl)disulfide and bis(3-(triethoxysilyl)propyl)tetrasulfide. Examples of the acid anhydride-containing silane coupling agent include 3-trimethoxysilylpropylsuccinic anhydride, 3-triethoxysilylpropylsuccinic anhydride, and 3-dimethylmethoxysilylpropylsuccinic anhydride.

[0049] Examples of the adhesion aid include not only silane coupling agents but also titanium coupling agents and zirconium coupling agents.

[0050] When an adhesion aid is used, it may be used alone or two or more kinds of adhesion aids may be used in combination. When an adhesion aid is used, the content thereof is preferably 0.3 to 15 parts by mass, more preferably 0.4 to 12 parts by mass, and even more preferably 0.5 to 10 parts by mass, relative to 100 parts by mass of the phenolic resin (A).

[0051] (surfactant) The negative photosensitive resin composition of this embodiment may contain a surfactant. By containing a surfactant, wettability during coating can be improved, and a uniform resin film and cured film can be obtained. Examples of surfactants include fluorine-based surfactants, silicone-based surfactants, alkyl-based surfactants, and acrylic-based surfactants.

[0052] The surfactant preferably contains a surfactant containing at least one of a fluorine atom and a silicon atom. This contributes to obtaining a uniform resin film (improving coating properties), improving developability, and also improving adhesive strength. Such surfactants are preferably nonionic surfactants containing at least one of a fluorine atom and a silicon atom. Commercially available surfactants that can be used include, for example, the "Megafac" series manufactured by DIC Corporation, including F-251, F-253, F-281, F-430, F-477, F-551, F-552, F-553, F-554, F-555, F-556, F-557, F-558, F-559, F-560, F-561, F-562, F-563, F-565, and F-566. fluorine-containing oligomer surfactants such as F-8, F-569, F-570, F-572, F-574, F-575, F-576, R-40, R-40-LM, R-41, and R-94; fluorine-containing nonionic surfactants such as Ftergent 250 and Ftergent 251 manufactured by Neos Corporation; and silicone surfactants such as the SILFOAM® series manufactured by Wacker Chemie (e.g., SD 100 TS, SD 670, SD 850, SD 860, and SD 882).

[0053] When the negative photosensitive resin composition contains a surfactant, the photosensitive resin composition may contain one or more surfactants. When the photosensitive resin composition contains a surfactant, the amount thereof is, for example, 0.001 to 1 part by mass, and preferably 0.005 to 0.5 parts by mass, relative to 100 parts by mass of the phenolic resin (A).

[0054] (solvent) The negative photosensitive resin composition of this embodiment preferably contains a solvent. This allows a photosensitive resin film to be easily formed on a stepped substrate by a coating method. When the negative photosensitive resin composition of this embodiment contains a solvent, the negative photosensitive resin composition of this embodiment is, for example, in the form of a varnish. The solvent typically includes an organic solvent, and there are no particular limitations on the organic solvent, so long as it can dissolve or disperse the above-mentioned components and does not substantially chemically react with the components.

[0055] Examples of organic solvents include acetone, methyl ethyl ketone, toluene, propylene glycol methyl ethyl ether, propylene glycol dimethyl ether, propylene glycol 1-monomethyl ether 2-acetate, diethylene glycol ethyl methyl ether, diethylene glycol monoethyl ether acetate, diethylene glycol monomethyl ether, Examples of the diol include propylene glycol monomethyl ether acetate, benzyl alcohol, propylene carbonate, ethylene glycol diacetate, propylene glycol diacetate, propylene glycol monomethyl ether acetate, dipropylene glycol methyl-n-propyl ether, butyl acetate, and γ-butyrolactone. These may be used alone or in combination.

[0056] When a solvent is used, it is used so that the concentration of nonvolatile components in the negative photosensitive resin composition is preferably 30 to 75% by mass, more preferably 35 to 70% by mass. By using a solvent in this range, each component can be sufficiently dissolved or dispersed. It also ensures good coatability, which in turn leads to improved flatness during spin coating. Furthermore, by adjusting the content of nonvolatile components, the viscosity of the negative photosensitive resin composition can be appropriately controlled.

[0057] (Other ingredients) In addition to the above components, the negative photosensitive resin composition of this embodiment may contain other components as needed, such as antioxidants, fillers such as silica, sensitizers, and film-forming agents.

[0058] (Characteristics of negative-type photosensitive resin composition) The negative photosensitive resin composition of this embodiment has a storage modulus of 2500 Pa or less at 250° C., but by satisfying other properties, performance such as reliability can be further improved.

[0059] In dynamic viscoelasticity measurement under the above [Conditions], the storage modulus at 100°C of the cured product of the negative photosensitive resin composition of this embodiment is preferably 2500 MPa or more, more preferably 2500 mPa or more and 3000 MPa or less, and even more preferably 3000 mPa or more and 2000 MPa or less.

[0060] In the dynamic viscoelasticity measurement under the above [Conditions], the value of the loss tangent (tan δ) at the peak temperature of the cured product of the negative photosensitive resin composition of this embodiment is preferably 0.01 or more and 0.8 or less, more preferably 0.1 or more and 0.6 or less.

[0061] The glass transition temperature (Tg) of the cured product of the negative slow-release resin composition of this embodiment is preferably 180° C. or higher, more preferably 200° C. or higher. The glass transition temperature of the cured product of the negative photosensitive resin composition is preferably 260° C. or lower, more preferably 240° C. or lower.

[0062] The tensile elongation at break of the cured product of the negative photosensitive resin composition of this embodiment when stretched at a tensile speed of 200 mm / min in accordance with JIS K7127 is preferably 40% or more, more preferably 40% or more and 200% or less, and even more preferably 50% or more and 150% or less.

[0063] [Cured resin film] A resin film is obtained by curing the photosensitive resin composition of this embodiment. The resin film of this embodiment is a dried or cured film of the photosensitive resin composition. That is, the resin film is obtained by drying or curing the photosensitive resin composition, and preferably by curing the photosensitive resin composition. This resin film is used to form, for example, a permanent film, a resin film for electronic devices such as a resist, etc. Among these, it is preferably used for applications requiring a permanent film, from the viewpoints of being able to obtain a resin film at low temperature, having excellent processability, and being able to obtain a resin film with excellent reliability. According to this embodiment, for example, it is possible to obtain a resin film obtained using a photosensitive resin composition that has excellent processability or reliability, which is required for making a resin film useful for producing electronic devices and the like.

[0064] The permanent film is a resin film obtained by pre-baking, exposing, and developing a photosensitive resin composition, patterning it into a desired shape, and then post-baking it to harden it. The permanent film can be used as a protective film for electronic devices such as a buffer coat film, an interlayer film such as an insulating film for rewiring, a dam material, etc.

[0065] The resist is composed of a resin film obtained by applying a negative photosensitive resin composition to an object to be masked by the resist by a method such as spin coating, roll coating, flow coating, dip coating, spray coating, or doctor coating, and then removing the solvent from the negative photosensitive resin composition.

[0066] FIG. 1 is a cross-sectional view showing an example of the configuration of an electronic device having a resin film according to this embodiment. 1 can be an electronic device including the resin film. Specifically, in the electronic device 100, one or more of the group consisting of the passivation film 32, the insulating layer 42, and the insulating layer 44 can be made of a resin film. Here, the resin film is preferably the permanent film described above.

[0067] The electronic device 100 is, for example, a semiconductor chip. In this case, a semiconductor package is obtained by mounting the electronic device 100 on a wiring substrate via bumps 52. The electronic device 100 includes a semiconductor substrate on which semiconductor elements such as transistors are provided, and a multilayer wiring layer (not shown) provided on the semiconductor substrate. The uppermost layer of the multilayer wiring layer includes an interlayer insulating film 30 and a top-layer wiring 34 provided on the interlayer insulating film 30. The top-layer wiring 34 is made of, for example, aluminum (Al). In addition, a passivation film 32 is provided on the interlayer insulating film 30 and the top-layer wiring 34. An opening is provided in a part of the passivation film 32 to expose the top-layer wiring 34.

[0068] A redistribution layer 40 is provided on the passivation film 32. The redistribution layer 40 has an insulating layer 42 provided on the passivation film 32, a redistribution line 46 provided on the insulating layer 42, and an insulating layer 44 provided on the insulating layer 42 and the redistribution line 46. An opening connected to the top-layer wiring 34 is formed in the insulating layer 42. The redistribution line 46 is formed on the insulating layer 42 and in the opening provided in the insulating layer 42, and is connected to the top-layer wiring 34. An opening connected to the redistribution line 46 is formed in the insulating layer 44.

[0069] Bumps 52 are formed in the openings provided in the insulating layer 44 via, for example, an under bump metallurgy (UBM) layer 50. The electronic device 100 is connected to a wiring board or the like via the bumps 52, for example.

[0070] Although the embodiments of the present invention have been described above, these are merely examples of the present invention, and various other configurations can also be adopted. [Example]

[0071] EXAMPLES The present invention will be described below with reference to examples and comparative examples, but the present invention is not limited to these.

[0072] (Examples 1 to 7, Comparative Example 1) A photosensitive resin composition was prepared according to the formulation shown in Table 1. Specifically, the components formulated according to Table 1 were first mixed by stirring under a nitrogen atmosphere, and then filtered through a polyethylene filter with a pore size of 0.2 μm to obtain a varnish-like photosensitive resin composition. Details of each component listed in Table 1 are shown below.

[0073] ((A) Phenolic resin) Phenolic resin a1: Biphenyl type phenolic resin, manufactured by Sumitomo Bakelite Co., Ltd., PR-X18121 (resin) Cyclic olefin polymer: Cyclic olefin polymer, manufactured by Sumitomo Bakelite Co., Ltd., R200309-2 ((B) Crosslinking Agent) Crosslinker b1: 1,3,4,6-tetrakis(methoxymethyl)glycoluril, manufactured by Daito Chemix, CROLIN-318 Crosslinking agent b2: 1,3,4,6-tetrakis(butoxymethyl)glycoluril, manufactured by Sanwa Chemical Co., Ltd., Nikalac MX-279 Crosslinking agent b3: 1,3-bis(methoxymethyl)-4,5-dimethoxy-2-imidazolinone, manufactured by Sanwa Chemical Co., Ltd., Nikalac MX-280 Crosslinking agent B4: Phenoxy-type epoxy resin, manufactured by Mitsubishi Chemical Corporation, YX-7105 Crosslinking agent b5: Epoxy resin (bisphenol A phenoxy), manufactured by Mitsubishi Chemical Corporation, JER-1256 Crosslinking agent b6: Bisphenol A epoxy resin, manufactured by Osaka Soda Co., Ltd., LX-01 Crosslinking agent b7: Phenol aralkyl resin, manufactured by Nippon Kayaku Co., Ltd., KAYAHARD GPH-103 Crosslinking agent b8: Dipentaerythritol polyacrylate, manufactured by Shin-Nakamura Chemical Co., Ltd., A-DPH ((C) Photosensitizer) Photosensitizer 1 (photoacid generator): Triarylsulfonium salt, manufactured by San-Apro Co., Ltd., CPI-210S Photosensitizer 2 (photoradical generator): 1,2-octanedione, 1-[4-(phenylthio)phenyl]-, 2-(o-benzoyloxime), BASF Japan Ltd., Irgacure OXE01 (adhesion aid) Adhesion aid 1: Trimethoxysilylpropylsuccinic anhydride, manufactured by Shin-Etsu Chemical Co., Ltd., X-12-967C Adhesion aid 2: 3-glycidoxypropyltrimethoxysilane, manufactured by Shin-Etsu Chemical Co., Ltd., KBM-403E

[0074] (surfactant) Surfactant 1: Fluorine-based surfactant, 3M Japan, FC4430 ·Surfactant 2: Oligomer containing fluorine-containing groups, hydrophilic groups, and lipophilic groups, manufactured by DIC , Megafuck F556 (solvent) Solvent 1: γ-butyrolactone, manufactured by Sanwa Yuka Kogyo Co., Ltd.

[0075] The resulting resin composition was measured for the following physical properties. (1. Dynamic viscoelasticity measurement of cured film (storage modulus measurement at 250℃ / 100℃)) (Preparation of test specimens) The photosensitive resin composition was spin-coated onto an 8-inch silicon wafer so that the film thickness after drying would be 10 μm, and then heated at 120° C. for 3 minutes to obtain a coating film. The resulting coating film was exposed to 1000 mJ / cm2 using a high-pressure mercury lamp. It was then baked at 120°C for 3 minutes after exposure, and then immersed in tetramethylammonium hydroxide for 60 seconds. It was then heated at 180°C for 120 minutes in a nitrogen atmosphere for curing. This resulted in a cured film of the photosensitive resin composition. The obtained cured product was cut together with the silicon wafer into 5 mm width pieces using a dicing saw, and the cut pieces were immersed in a 2 mass % aqueous solution of hydrofluoric acid to peel the cured film from the wafer. The peeled cured film was dried at 60°C for 10 hours to obtain a test piece (30 mm x 5 mm x 10 µm thick).

[0076] (Measurement of storage modulus) The obtained test pieces were heated from 30 to 300°C in a nitrogen atmosphere using a dynamic viscoelasticity measuring device (TA Q800) at a frequency of 1 Hz, in tension mode, and at a heating rate of 5°C / min, to measure the storage modulus versus temperature. The storage modulus (E') curves obtained were used to read the storage modulus [MPa] at 100°C and 250°C.

[0077] (2. Measurement of Tensile Elongation) Test specimens were prepared in the same manner as in (Preparation of Test Specimens) in (1. Measurement of Dynamic Viscoelasticity of Cured Films) above. A tensile test was carried out on the test specimens using a tensile tester (Tensilon RTC-1210A, manufactured by Orientec Co., Ltd.) in an atmosphere of 23°C according to a method conforming to JIS K 7161, and the tensile elongation of the test specimens was measured. The elongation rate in the tensile test was 5 mm / min. The tensile elongation is expressed in %.

[0078] (3. Measurement of the glass transition temperature of the cured film) Test specimens were prepared in the same manner as in (Preparation of Test Specimens) in (1. Measurement of Dynamic Viscoelasticity of Cured Films) above. The test specimens were heated to 300°C at a heating rate of 10°C / min using a thermomechanical analyzer (TMA / SS6000, manufactured by Seiko Instruments Inc.). The thermal expansion coefficients of the obtained test specimens were measured. The glass transition temperature Tg (unit: °C) of the cured product was then calculated from the inflection point of the temperature-thermal expansion coefficient graph obtained from the measurement results. A higher Tg of the cured film means that the cured film is more stable against heat.

[0079] (4. Measurement of loss tangent (tanδ)) Test specimens were prepared in the same manner as in (1. Measurement of dynamic viscoelasticity of cured films) (Preparation of test specimens) above. The test specimens were heated from 30°C to 300°C at a heating rate of 10°C / min, and then cooled from 300°C to 200°C at a heating rate of 10°C / min. After that, the mechanical loss tangent (tanδ) was measured at 200°C using a dynamic viscoelasticity measuring device (Seiko Instruments Inc., "DMS6100") with a chuck distance of 8 mm, a frequency of 10 Hz, and in tension mode. A higher value of tanδ indicates better flexibility.

[0080] (Low temperature curing (curing temperature)) The photosensitive resin composition obtained above was spin-coated onto an 8-inch silicon wafer so that the film thickness after drying would be 10 μm, and cured by heat treatment in an inert oven (Koyo Thermo Systems, product number CLH-21CD-(V)-S) under a nitrogen atmosphere according to the following temperature settings and internal temperature measurements. The curing temperatures are shown in Table 1. 180°C curing: Room temperature (30°C) → Heat to 180°C over 30 minutes → Maintain at 180°C for 2 hours → Cool to room temperature over 30 minutes 200°C curing: Room temperature (30°C) → Heat to 200°C over 34 minutes → Maintain at 200°C for 2 hours → Cool to room temperature over 34 minutes

[0081] [Table 1]

[0082] The resin compositions of the examples were excellent in low-temperature curing properties. [Explanation of symbols]

[0083] 30 Interlayer insulating film 32 Passivation film 34 Top layer wiring 40 Redistribution layer 42, 44 Insulation layer 46 Rewiring 50 UBM layers 52 Bump 100 Electronic equipment

Claims

1. A negative photosensitive resin composition used in a rewiring layer of a semiconductor device, comprising: The negative photosensitive resin composition comprises: (A) a phenolic resin, (B) a crosslinking agent, and (C) a photosensitizer, The phenolic resin (A) includes a biphenyl-type phenolic resin, the crosslinking agent (B) contains a difunctional or higher functional urea resin crosslinking agent and a difunctional or higher functional epoxy resin crosslinking agent, The negative photosensitive resin composition has a storage modulus at 250°C of 2500 MPa or less when cured by dynamic mechanical analysis (DMA).

2. The negative photosensitive resin composition according to claim 1, The negative photosensitive resin composition has a storage modulus at 100°C of 2500 MPa or more when cured by DMA (dynamic viscoelasticity measurement).

3. The negative photosensitive resin composition according to claim 1 or 2, The negative photosensitive resin composition has a loss tangent (tanδ) at a peak temperature of 0.01 or more and 0.8 or less, which is obtained by dynamic mechanical analysis (DMA) when the negative photosensitive resin composition is cured.

4. The negative photosensitive resin composition according to any one of claims 1 to 3, The negative photosensitive resin composition has a glass transition temperature (Tg) of 180°C or higher when cured, as measured by dynamic mechanical analysis (DMA).

5. The negative photosensitive resin composition according to any one of claims 1 to 4, The negative photosensitive resin composition has a tensile elongation at break of 40% or more when the negative photosensitive resin composition is cured and stretched at a tensile speed of 200 mm / min in accordance with JIS K7127.

6. The negative photosensitive resin composition according to claim 1 , wherein the bifunctional or higher functional urea resin-based crosslinking agent comprises an alkoxymethylated glycoluril compound.

7. 7. The negative photosensitive resin composition according to claim 1, wherein the bifunctional or higher functional epoxy resin crosslinking agent is a phenoxy epoxy resin.

8. 8. The negative photosensitive resin composition according to claim 1, wherein the weight average molecular weight of the biphenyl-type phenolic resin is 2,000 or more and 50,000 or less.

9. further comprising an acid generator; The negative photosensitive resin composition according to claim 1 , wherein the acid generator comprises a sulfonium compound or a salt thereof.

10. A cured film obtained by curing the negative photosensitive resin composition according to claim 1 .

11. A semiconductor element; a redistribution layer provided on a surface of the semiconductor element, A semiconductor device, wherein an insulating layer in the rewiring layer is made of the cured film according to claim 10.

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