Positive-type photosensitive resin composition, cured film, and semiconductor device.

Abstract

The present invention provides: a positive photosensitive resin composition which makes it possible to produce a resin film that has excellent resistance to brittle fracture; and a highly reliable cured film and a highly reliable semiconductor device. A positive photosensitive resin composition according to the present invention is used for a resin film of a semiconductor device, and contains a biphenyl-type phenolic resin (A1), a urea resin-based crosslinking agent (B1) and a sensitizing agent (C). The urea resin-based crosslinking agent (B1) is mainly composed of a bifunctional compound or a trifunctional compound. A cured product of this positive photosensitive resin composition has a tensile elongation of 40% or more.

Description

Technical Field

[0001] The present invention relates to a positive photosensitive resin composition, a cured film, and a semiconductor device.

Background Art

[0002] The redistribution layer of a semiconductor device has an insulating layer and a wiring layer. Among these, the insulating layer is formed using a photosensitive resin composition and patterned into a desired shape.

[0003] For example, Patent Document 1 discloses a photosensitive resin composition containing an alkali aqueous solution-soluble resin, a crosslinking agent, a photopolymerization initiator, and an epoxy resin (thermosetting resin). And it is disclosed that by using this photosensitive resin composition, a cured product excellent in flexibility, adhesion, pencil hardness, solvent resistance, acid resistance, heat resistance, gold plating resistance, etc. can be obtained. Further, it is disclosed that this cured product is used as an interlayer insulating material for electronic components.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] With the advancement and complexity of electronic devices, semiconductor devices are required to have higher reliability than before. Therefore, it is required to improve the reliability of electronic devices by improving the cured product and the photosensitive resin composition for obtaining this cured product. In particular, suppression of brittle fracture accompanying temperature changes and the like has become a problem.

[0006] An object of the present invention is to provide a positive photosensitive resin composition capable of producing a resin film excellent in resistance to brittle fracture, as well as a highly reliable cured film and a semiconductor device. [Means for solving the problem]

[0007] These objectives are achieved by the present invention as described in (1) to (9) below. (1) A positive-type photosensitive resin composition used in resin films of semiconductor devices, Biphenyl-type phenolic resin (A1), Urea resin-based crosslinking agent (B1), Photosensitive material (C), Includes, The urea resin-based crosslinking agent (B1) mainly consists of a bifunctional compound or a trifunctional compound. A positive-type photosensitive resin composition characterized in that the tensile elongation of the cured product of the positive-type photosensitive resin composition is 40% or more.

[0008] (2) The urea resin crosslinking agent (B1) is the positive-type photosensitive resin composition according to (1) above, further comprising a tetrafunctional compound.

[0009] (3) The urea resin crosslinking agent (B1) is the positive-type photosensitive resin composition according to (1) or (2) above, wherein the average number of functional groups per molecule is 1.5 or more and 3.5 or less.

[0010] (4) A positive-type photosensitive resin composition according to any one of (1) to (3) above, further comprising an epoxy resin crosslinking agent (B2).

[0011] (5) The positive-type photosensitive resin composition according to (4) above, wherein the content of the urea resin-based crosslinking agent (B1) is greater than the content of the epoxy resin-based crosslinking agent (B2).

[0012] (6) The positive-type photosensitive resin composition according to any one of (1) to (5) above, wherein the glass transition temperature of the cured product is 200°C or more and 300°C or less.

[0013] (7) A positive-type photosensitive resin composition according to any one of (1) to (6) above, further comprising an adhesion aid (D).

[0014] (8) A cured film characterized by being composed of a cured product of the positive photosensitive resin composition according to any one of (1) to (7) above.

[0015] (9) A semiconductor element, A resin film provided on the surface of the semiconductor element, Comprising: A semiconductor device, wherein the resin film contains the cured film according to (8) above. [Effect of the Invention]

[0016] According to the present invention, a positive photosensitive resin composition capable of producing a resin film excellent in resistance to brittle fracture can be obtained. Further, according to the present invention, a highly reliable cured film and a semiconductor device can be obtained. [Brief Description of the Drawings]

[0017] [Figure 1] FIG. 1 is a cross-sectional view showing a semiconductor device (semiconductor device according to an embodiment) including a resin film according to an embodiment. [Figure 2] FIG. 2 is an enlarged observation image showing the interfacial state between a copper wiring portion and a copper oxide film produced using the positive photosensitive resin composition of Example 1.​​​​​​​​​​​​​​​​The positive-type photosensitive resin composition according to this embodiment is a resin material used to form a resin film for semiconductor devices. The positive-type photosensitive resin composition according to this embodiment comprises a biphenyl-type phenolic resin (A1), a urea resin-based crosslinking agent (B1), and a photosensitive agent (C). The urea resin-based crosslinking agent (B1) mainly consists of a bifunctional or trifunctional compound. The positive-type photosensitive resin composition according to this embodiment has a tensile elongation of 40% or more in its cured product.

[0020] Such a positive-type photosensitive resin composition, having the above-described structure, enables the production of a resin film with excellent resistance to brittle fracture. Such a resin film can be used in semiconductor devices and contribute to the realization of semiconductor devices with good resistance to temperature cycling tests, for example. Furthermore, when such a resin film is used, for example, in the fabrication of a redistribution layer, it contributes to reducing the thickness of the oxide film that forms on the surface of the wiring portion. This makes it possible to suppress, for example, the occurrence of warping of the semiconductor wafer due to an increase in the thickness of the oxide film. Moreover, such a resin film suppresses the occurrence of voids and cracks at the interface with the wiring portion. This makes it possible to improve the reliability of the redistribution layer.

[0021] 1.1. Biphenyl-type phenolic resin (A1) Biphenyl-type phenolic resin (A1) is a phenolic resin having a bisphenol structure. Preferably, a biphenyl-type phenolic resin having a structural unit with a bisphenol skeleton represented by the following formula (2) is used. This improves the low-temperature curability and reliability of the cured film of the positive-type photosensitive resin composition.

[0022] [ka]

[0023] In equation (2) above, R 41 and R 42Each of these is 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, and these may be linked via ester bonds, ether bonds, amide bonds, or carbonyl bonds. Furthermore, r and s are independently integers from 0 to 3, and Y4 and Z4 are independently selected from the group consisting of an aliphatic group having 1 to 10 carbon atoms, a alicyclic group having 3 to 20 carbon atoms, and an organic group having an aromatic structure having 6 to 20 carbon atoms, which may have single or unsaturated bonds. Note that Z4 is bonded to one of the two benzene rings.

[0024] The weight-average molecular weight of the biphenyl-type phenolic resin (A1) is preferably 12,000 or more, more preferably 15,000 or more, and even more preferably 20,000 or more. This enhances the curability of the positive-type photosensitive resin composition and increases the elongation of the cured film. Furthermore, the weight-average molecular weight of the biphenyl-type phenolic resin (A1) is preferably 500,000 or less, more preferably 400,000 or less, and even more preferably 200,000 or less. This ensures appropriate solubility of the positive-type photosensitive resin composition in the solvent.

[0025] A biphenyl-type phenolic resin (A1) having the structural unit represented by the above formula (2) can be obtained, for example, by the method described in Japanese Patent Application Publication No. 2018-155938.

[0026] The content of biphenyl-type phenolic resin (A1) in the positive-type photosensitive resin composition is preferably 5% by mass or more, more preferably 10% by mass or more, and even more preferably 15% by mass or more, based on the total solids of the positive-type photosensitive resin composition. This enhances the curability of the positive-type photosensitive resin composition. Furthermore, the content of biphenyl-type phenolic resin (A1) in the positive-type photosensitive resin composition is preferably 70% by mass or less, more preferably 60% by mass or less, and even more preferably 50% by mass or less, based on the total solids of the positive-type photosensitive resin composition. This suppresses a decrease in the elongation of the cured film.

[0027] 1.2. Other phenolic resins (A2) The positive-type photosensitive resin composition according to this embodiment may further contain a phenolic resin (A2) other than the biphenyl-type phenolic resin (A1).

[0028] Examples of phenolic resins (A2) include novolac-type phenolic resins such as phenol 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 and aldehyde compounds such as novolac-type phenolic resin, resol-type phenolic resin, and cresol novolac resin; and reaction products of phenolic compounds and dimethanol compounds such as phenol aralkyl resin.

[0029] Among these, the phenolic resin (A2) is preferably a resin having the structure represented by the following formula (1) from the viewpoint of obtaining a low-temperature curable resin composition. Including such a phenolic resin (A2) can improve the curability of the positive-type photosensitive resin composition and the elongation of the cured film.

[0030] [ka]

[0031] In formula (1) above, n is preferably 6 or more, more preferably 10 or more, and even more preferably 14 or more. This makes it possible to improve the curability of the positive-type photosensitive resin composition and the elongation of the cured film.

[0032] Furthermore, from the viewpoint of solvent solubility, n is preferably 72 or less, more preferably 54 or less, and even more preferably 36 or less.

[0033] The weight-average molecular weight of the phenolic resin (A2) is preferably 500 or more, more preferably 2,000 or more, and even more preferably 4,000 or more. This enhances curability and the elongation of the cured film. Furthermore, the weight-average molecular weight of the phenolic resin (A2) is preferably 50,000 or less, more preferably 20,000 or less, and even more preferably 10,000 or less. This ensures appropriate solubility in the solvent.

[0034] When the positive-type photosensitive resin composition contains phenolic resin (A2), the content of phenolic resin (A2) is preferably 5% by mass or more, more preferably 10% by mass or more, and even more preferably 15% by mass or more, based on the total solids of the positive-type photosensitive resin composition. This ensures good curability. Furthermore, the content of phenolic resin (A2) in the positive-type photosensitive resin composition is preferably 70% by mass or less, more preferably 60% by mass or less, and even more preferably 50% by mass or less, based on the total solids of the positive-type photosensitive resin composition. This suppresses a decrease in the elongation of the cured film.

[0035] The total content of biphenyl-type phenolic resin (A1) and phenolic resin (A2) in the positive-type photosensitive resin composition is preferably 30% by mass or more, more preferably 45% by mass or more, and even more preferably 55% by mass or more, of the total solids of the positive-type photosensitive resin composition, particularly from the viewpoint of improving curability at low temperatures and the reliability of the cured film. Furthermore, the total content of biphenyl-type phenolic resin (A1) and phenolic resin (A2) in the positive-type photosensitive resin composition is preferably 95% by mass or less, more preferably 90% by mass or less, and even more preferably 85% by mass or less, of the total solids of the positive-type photosensitive resin composition, from the viewpoint of improving photosensitivity and the chemical resistance of the cured film.

[0036] Furthermore, the positive-type photosensitive resin composition according to this embodiment may also contain thermosetting resins other than the phenolic resins (A1) and (A2). Examples of such thermosetting resins include hydroxystyrene resins, polyamide resins, polybenzoxazole resins, polyimide resins, and cyclic olefin resins.

[0037] 1.3. Urea resin-based crosslinking agent (B1) As the urea resin crosslinking agent (B1), a urea resin crosslinking agent mainly composed of a difunctional compound or a trifunctional compound is used. A difunctional compound is a compound in which the number of functional groups contributing to crosslinking is two per molecule, and a trifunctional compound is a compound in which the number of functional groups contributing to crosslinking is three per molecule.

[0038] The presence of these compounds as the main components enhances the elongation of the cured positive-type photosensitive resin composition. Difunctional and trifunctional compounds have relatively fewer crosslinking sites compared to, for example, compounds with four or more functional groups per molecule, thus preventing the crosslinked structure from becoming excessively rigid. This contributes to increasing the elongation of the cured product. Furthermore, difunctional and trifunctional compounds have relatively more crosslinking sites compared to, for example, compounds with one functional group per molecule, resulting in a relatively stronger crosslinked structure and contributing to increased mechanical strength of the cured product. This allows for the production of a positive-type photosensitive resin composition capable of manufacturing resin films with excellent resistance to brittle fracture. The main component refers to the component with the highest mass ratio content in the urea resin-based crosslinking agent. Examples of functional groups include methylol groups and alkoxymethyl groups.

[0039] Furthermore, when such a resin film is used, for example, in the fabrication of a redistribution layer, it contributes to reducing the thickness of the oxide film that forms on the surface of the wiring. This suppresses the occurrence of warping of the semiconductor wafer that is caused by the thickening of the oxide film. One reason for this effect is that the resin film made using the positive-type photosensitive resin composition according to this embodiment has low oxygen permeability. A resin film with low oxygen permeability reduces the opportunity for contact between oxygen in the atmosphere and the wiring. This is thought to suppress the oxidation of the metal constituting the wiring and inhibit the formation of an oxide film.

[0040] Furthermore, such resin films are thought to contribute to suppressing the occurrence of voids and cracks at the interface with the wiring. By suppressing the occurrence of voids, the reliability of the rewiring layer is improved. One reason for this effect is that, as mentioned above, oxidation of the wiring is suppressed, so even if an oxide film is formed, its thickness can be reduced. As a result, even if the wiring deforms due to temperature changes, the oxide film can more easily follow that deformation.

[0041] The urea resin crosslinking agent (B1) may contain either a bifunctional compound or a trifunctional compound as its main component, or it may also contain the other, or a compound having one or four or more functional groups per molecule.

[0042] Furthermore, the content of the aforementioned main component in the urea resin crosslinking agent (B1) is preferably 55% by mass or more, and more preferably 65% ​​by mass or more. This allows for a sufficiently high elongation of the cured film.

[0043] Examples of difunctional compounds used in urea resin crosslinking agents (B1) include difunctional methylolated urea compounds and difunctional alkoxymethylated urea compounds. An alkoxymethylated urea compound is a compound in which the hydrogen atom of the amino group of a urea compound is replaced with a methylol group or an alkoxymethyl group. A urea compound is a compound that contains a urea structure (-NC(=O)N-).

[0044] Examples of bifunctional compounds include glycoluryl compounds such as dihydroxymethylated glycoluryl, dimethoxymethylated glycoluryl, diethoxymethylated glycoluryl, dipropoxymethylated glycoluryl, and dibutoxymethylated glycoluryl; urea compounds such as bismethoxymethylurea, bisethoxymethylurea, bispropoxymethylurea, and bisbutoxymethylurea; dihydroxymethylated ethyleneurea, dimethoxymethylated ethyleneurea, diethoxymethylated ethyleneurea, and dipropoxy Examples include ethyleneurea compounds such as methylated ethyleneurea and dibutoxymethylated ethyleneurea, propyleneurea compounds such as dihydroxymethylated propyleneurea, dimethoxymethylated propyleneurea, diethoxymethylated propyleneurea, dipropoxymethylated propyleneurea, and dibutoxymethylated propyleneurea, and imidazolidinone compounds such as 1,3-di(methoxymethyl)-4,5-dihydroxy-2-imidazolidinone and 1,3-di(methoxymethyl)-4,5-dimethoxy-2-imidazolidinone.

[0045] Examples of trifunctional compounds include glycoluryl compounds such as trihydroxymethylated glycoluryl, trimethoxymethylated glycoluryl, triethoxymethylated glycoluryl, trippropoxymethylated glycoluryl, and tripbutoxymethylated glycoluryl.

[0046] Examples of tetrafunctional compounds include glycoluryl compounds such as tetrahydroxymethylated glycoluryl, tetramethoxymethylated glycoluryl, tetraethoxymethylated glycoluryl, tetrapropoxymethylated glycoluryl, and tetrabutoxymethylated glycoluryl.

[0047] Furthermore, the urea resin-based crosslinking agent (B1) is preferably a crosslinking agent mainly composed of a bifunctional compound. This makes it possible to particularly enhance the elongation of the cured product of the positive-type photosensitive resin composition.

[0048] Furthermore, in the case of urea resin-based crosslinking agent (B1), a combination of a bifunctional compound and a tetrafunctional compound may be used. This results in a cured product that possesses both a flexible crosslinked structure derived from the bifunctional compound and a rigid crosslinked structure derived from the tetrafunctional compound. Therefore, while suppressing a decrease in elongation and mechanical strength of the cured product, the glass transition temperature of the cured product can be increased due to the rigid structure. As a result, a resin film with excellent deformation resistance (heat resistance) at high temperatures can be obtained.

[0049] When used in combination as described above, the mixing ratio β2 / (β2+β4) of the content β2 of the difunctional compound to the content β4 of the tetrafunctional compound is preferably 0.55 to 0.95 by mass, and more preferably 0.65 to 0.80. This allows for sufficient increases in the elongation and mechanical strength of the cured product, and also sufficiently increases the glass transition temperature of the cured product. As a result, a positive-type photosensitive resin composition is obtained that exhibits particularly good resistance to brittle fracture and excellent deformation resistance at high temperatures. Furthermore, if the mixing ratio β2 / (β2+β4) of the content β2 of the difunctional compound to the content β4 of the tetrafunctional compound is within the above range, a resin film with particularly low oxygen permeability can be realized while increasing the elongation and mechanical strength of the cured product. Moreover, when such a resin film is used, for example, to produce a redistribution layer, the formation of an oxide film is suppressed, and the generation of voids and the like at the interface between the wiring portion and the oxide film is suppressed.

[0050] The content of the urea resin-based crosslinking agent (B1) in the positive-type photosensitive resin composition is preferably 5% by mass or more, more preferably 10% by mass or more, and even more preferably 15% by mass or more, based on the total solids of the positive-type photosensitive resin composition. This allows for a sufficient increase in the elongation of the cured product of the positive-type photosensitive resin composition. Furthermore, the content of the urea resin-based crosslinking agent (B1) in the positive-type photosensitive resin composition is preferably 50% by mass or less, more preferably 40% by mass or less, and even more preferably 30% by mass or less, based on the total solids of the photosensitive resin composition. This suppresses a decrease in the mechanical strength of the cured product.

[0051] Furthermore, the urea resin crosslinking agent (B1) preferably has an average number of functional groups per molecule of 1.5 to 3.5, more preferably 1.8 to 3.3, and even more preferably 1.9 to 2.9. This makes it possible to particularly increase the elongation of the cured product of the positive-type photosensitive resin composition, and also increase the tensile strength and glass transition temperature of the cured product. Moreover, if the average number of functional groups per molecule of the urea resin crosslinking agent (B1) is within the above range, it is possible to realize a resin film with particularly low oxygen permeability while increasing the elongation and mechanical strength of the cured product. Furthermore, it is possible to suppress the generation of voids and the like at the interface between the wiring portion and the oxide film.

[0052] The average number of functional groups per molecule can be calculated based on the number of functional groups and blending ratio of the urea resin-based crosslinking agent (B1) contained in the positive-type photosensitive resin composition. For example, if a bifunctional compound and a tetrafunctional compound are blended in equal amounts, the average number of functional groups will be 3.

[0053] 1.4. Epoxy resin-based crosslinking agent (B2) The positive-type photosensitive resin composition according to this embodiment preferably contains an epoxy resin-based crosslinking agent (B2). This allows the cured product of the positive-type photosensitive resin composition to have a desired range of tensile breaking strength. Preferably, a bifunctional or higher epoxy resin having an alkylene structure with ether bonds having 4 or more carbon atoms is used as the epoxy resin-based crosslinking agent (B2). Such an epoxy resin functions as a crosslinking agent and also has both a rigid and a flexible structure, which can impart flexibility to the cured product of the positive-type photosensitive resin composition. As a result, the elongation of the cured product can be increased without impairing the breaking strength of the cured product. A rigid structure refers to a structure that includes aromatic ring structures, such as condensed aromatic ring structures such as benzene rings, naphthalene rings, anthracene rings, and pyrene rings; aromatic ring structures such as biphenol rings, cardo structures, and fluorene rings; and heterocyclic structures such as pyrrole rings and thiophene rings. A flexible structure refers to a structure that contains aliphatic hydrocarbons, such as alkylene groups with 1 to 8 carbon atoms, ethylene glycol groups, propylene glycol groups, butylene glycol groups, etc.

[0054] The epoxy resin crosslinking agent (B2) is preferably a compound in which part or all of the epoxy resin has a flexible structure selected from an alkylene structure having 2 to 20 carbon atoms and an alkylene structure having ether bonds with 2 to 20 carbon atoms. Examples of such epoxy resin crosslinking agents (B2) include EXA-4850-150, EXA-4816, and EXA-4822 (epoxy resins having an alkylene structure with ether bonds) manufactured by DIC Corporation; EP-4000S, EP-4000SS, EP-4003S, EP-4010S, and EP-4011S (epoxy resins containing an alkylene structure with ether bonds) manufactured by ADEKA Corporation; BEO-60E and BPO-20E (epoxy resins having an alkylene structure with ether bonds) manufactured by Shin Nippon Rika Co., Ltd.; YX-7105, YX-7110, and YX-7400 (epoxy resins having an alkylene structure with ether bonds), and YX-7180 ​​(phenoxy resin having an alkylene structure with ether bonds) manufactured by Mitsubishi Chemical Corporation. The epoxy resin crosslinking agent (B2) may be used alone or in combination of two or more types.

[0055] From the viewpoint of increasing the elongation of the cured product, the content of the epoxy resin crosslinking agent (B2) in the positive-type photosensitive resin composition is preferably 3% by mass or more, more preferably 5% by mass or more, and even more preferably 10% by mass or more, based on the total solids of the positive-type photosensitive resin composition. Furthermore, from the viewpoint of suppressing a decrease in mechanical strength during curing, the content of the epoxy resin crosslinking agent (B2) in the positive-type photosensitive resin composition is preferably 40% by mass or less, more preferably 30% by mass or less, and even more preferably 20% by mass or less, based on the total solids of the positive-type photosensitive resin composition.

[0056] The content of the urea resin-based crosslinking agent (B1) mentioned above may be less than or equal to the content of the epoxy resin-based crosslinking agent (B2), but it is preferable that it be greater than the content of the epoxy resin-based crosslinking agent (B2). This achieves both the effect of increasing the elongation of the cured product and the effect of ensuring tensile breaking strength. As a result, a cured product with excellent resistance to temperature cycling tests can be obtained, for example.

[0057] When the ratio of the content of urea resin-based crosslinking agent (B1) to the content of epoxy resin-based crosslinking agent (B2) is (B1 / B2), B1 / B2 is preferably 1.05 or more and 1.67 or less, and more preferably 1.10 or more and 1.50 or less.

[0058] The positive-type photosensitive resin composition may contain other epoxy resins (D2) besides the epoxy resin crosslinking agent (B2). Examples of other epoxy resins (D2) include bisphenol A type phenoxy resin, bisphenol F type phenoxy resin, bisphenol S type phenoxy resin, bisphenolacetophenone type phenoxy resin, novolac type phenoxy resin, biphenyl type phenoxy resin, fluorene type phenoxy resin, dicyclopentadiene type phenoxy resin, norbornene type phenoxy resin, naphthalene type phenoxy resin, anthracene type phenoxy resin, adamantane type phenoxy resin, terpene type phenoxy resin, trimethylcyclohexane type phenoxy resin, and the like.

[0059] 1.5. Other crosslinking agents (B3) The positive-type photosensitive resin composition may contain a crosslinking agent (B3) other than the urea resin-based crosslinking agent (B1) and the epoxy resin-based crosslinking agent (B2).

[0060] Examples of crosslinking agents (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 phloroglucides; 1,4-bis(methoxymethyl)benzene, 1,3-bis(methoxymethyl)benzene, 4,4'-bis(methoxymethyl)biphenyl, 3,4'-bis(methoxymethyl)biphenyl, and 3,3'-bis(methoxymethyl) Examples include compounds having alkoxymethyl groups such as methyl(2,6-naphthalenedicarboxylate) and methyl(4,4'-methylenebis(2,6-dimethoxymethylphenol); methylolmelamine compounds represented by hexamethylmelamine and hexasubtanolmelamine; alkoxymelamine compounds such as hexamethoxymelamine; cyano compounds such as dicyanoaniline, dicyanophenol, and cyanophenylsulfonic acid; isocyanate compounds such as 1,4-phenylenediisocyanate and 3,3'-dimethyldiphenylmethane-4,4'-diisocyanate; and maleimide compounds such as N,N'-1,3-phenylenedimaleimide and N,N'-methylenedimaleimide.

[0061] The total content of urea resin-based crosslinking agent (B1), epoxy resin-based crosslinking agent (B2), and other crosslinking agents (B3) in the positive-type photosensitive resin composition is preferably 10% by mass or more, more preferably 20% by mass or more, and even more preferably 30% by mass or more, based on the total solids of the positive-type photosensitive resin composition. This allows for sufficient improvement of the elongation and mechanical strength of the cured product of the positive-type photosensitive resin composition. Furthermore, the total content of urea resin-based crosslinking agent (B1), epoxy resin-based crosslinking agent (B2), and other crosslinking agents (B3) in the positive-type photosensitive resin composition is preferably 60% by mass or less, more preferably 50% by mass or less, and even more preferably 40% by mass or less, based on the total solids of the positive-type photosensitive resin composition. This suppresses a decrease in the mechanical strength of the cured product.

[0062] 1.6. Photosensitive material (C) Examples of photosensitive agents (C) include acid generators that generate acid by absorbing thermal or light energy. By including an acid generator, a positive-type photosensitive resin composition capable of stably forming a cured product can be obtained. Examples of such acid generators include thermal acid generators (c1) that generate acid with thermal energy, and photoacid generators (c2) that generate acid with light energy, and one or both of these can be used.

[0063] A sulfonium compound or a salt thereof is preferably used as the thermal acid generator (c1).

[0064] The sulfonium compound or its salt is specifically a sulfonium salt having a sulfonium ion as the cation. The anionic portion of the sulfonium compound or its salt is specifically a sulfonic acid ion such as a boride ion, antimony ion, phosphorus ion, or trifluoromethanesulfonate ion, and is preferably a boride ion or antimony ion, and more preferably a boride ion, from the viewpoint of improving the reaction rate at low temperatures. These anions may have substituents.

[0065] The sulfonium compound or its salt preferably includes a sulfonium salt represented by the following formula (4).

[0066] [ka]

[0067] In the above equation (4), R 1 is a hydrogen atom or a monovalent organic group, preferably a hydrogen atom or an acyl group, more preferably an acyl group, and even more preferably a CH3C(=O)- group.

[0068] R 2 The group is a monovalent organic group, preferably a hydrocarbon group having a chain or branched chain, or a benzyl group which may have substituents, more preferably a benzyl group which may be substituted with an alkyl group having 1 to 4 carbon atoms, and even more preferably a benzyl group in which a methyl group or an aromatic ring portion which may be substituted with a methyl group.

[0069] R 3 The group is a monovalent organic group, and from the viewpoint of improving reactivity at low temperatures, it is preferably a hydrocarbon group having a chain or branched chain, more preferably an alkyl group having 1 to 4 carbon atoms, and more preferably a methyl group.

[0070] Examples of the thermal acid generator (c1) include triphenylsulfonium salts such as triphenylsulfonium trifluoromethanesulfonate.

[0071] Examples of photoacid generators (c2) include naphthoquinone diazide compounds, diarylsulfonium salts, triarylsulfonium salts, dialkylphenacylsulfonium salts, diaryliodonium salts, aryldiazonium salts, aromatic tetracarboxylic acid esters, aromatic sulfonic acid esters, nitrobenzyl esters, aromatic N-oxyimide sulfonates, aromatic sulfamides, and benzoquinone diazosulfonic acid esters. Among these, naphthoquinone diazide compounds are preferred.

[0072] Examples of naphthoquinone diazide compounds that can be used include naphthoquinone diazide adducts of tris(4-hydroxyphenyl)-1-ethyl-4-isopropylbenzene and naphthoquinone diazide adducts of tetrahydroxybenzophenone. Here, the addition of naphthoquinone diazide can be produced, for example, by reacting o-quinone diazide sulfonyl chlorides with hydroxy compounds or amino compounds.

[0073] From the viewpoint of improving curability, the content of photosensitive agent (C) in the positive-type photosensitive resin composition is preferably 3% by mass or more, more preferably 5% by mass or more, and even more preferably 8% by mass or more, of the total solids of the positive-type photosensitive resin composition. Furthermore, from the viewpoint of suppressing a decrease in reliability, the content of photosensitive agent (C) in the positive-type photosensitive resin composition is preferably 20% by mass or less, more preferably 18% by mass or less, and even more preferably 16% by mass or less, of the total solids of the positive-type photosensitive resin composition.

[0074] The photosensitive agent (C) is preferably composed of both a thermal acid generator (c1) and a photoacid generator (c2). This increases the mechanical strength of the cured product of the positive-type photosensitive resin composition. When the photosensitive agent (C) is composed of both a thermal acid generator (c1) and a photoacid generator (c2), the above content refers to the total content of these two components.

[0075] When the mixing ratio of the thermal acid generator (c1) and the photoacid generator (c2) is c1:c2, the mass ratio is preferably 2:8 to 8:2, more preferably 3:7 to 7:3, and even more preferably 4:6 to 6:4. This makes it possible to increase the elongation without impairing the mechanical strength of the cured product.

[0076] 1.7. Adhesion enhancer (D) The positive-type photosensitive resin composition according to this embodiment preferably contains an adhesion aid (D). This makes it possible to further improve the adhesion between the cured product of the positive-type photosensitive resin composition and the substrate.

[0077] Examples of adhesion aids (D) include silane coupling agents such as amino group-containing silane coupling agents, epoxy group-containing silane coupling agents, (meth)acryloyl group-containing silane coupling agents, mercapto group-containing silane coupling agents, vinyl group-containing silane coupling agents, ureido group-containing silane coupling agents, sulfide group-containing silane coupling agents, and acid anhydride-containing silane coupling agents, as well as titanium coupling agents and zirconium coupling agents. When using these coupling agents, one type may be used alone, or two or more types may be used in combination.

[0078] 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.

[0079] Examples of epoxy group-containing silane coupling agents include γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, and γ-glycidylpropyltrimethoxysilane.

[0080] Examples of silane coupling agents containing a (meth)acryloyl group include γ-((meth)acryloyloxypropyl)trimethoxysilane, γ-((meth)acryloyloxypropyl)methyldimethoxysilane, and γ-((meth)acryloyloxypropyl)methyldiethoxysilane.

[0081] Examples of mercapto group-containing silane coupling agents include 3-mercaptopropyltrimethoxysilane.

[0082] Examples of vinyl group-containing silane coupling agents include vinyltris(β-methoxyethoxy)silane, vinyltriethoxysilane, and vinyltrimethoxysilane.

[0083] Examples of ureido group-containing silane coupling agents include 3-ureidopropyltriethoxysilane.

[0084] Examples of sulfide group-containing silane coupling agents include bis(3-(triethoxysilyl)propyl) disulfide and bis(3-(triethoxysilyl)propyl) tetrasulfide.

[0085] Examples of acid anhydride-containing silane coupling agents include 3-trimethoxysilylpropyl succinic anhydride, 3-triethoxysilylpropyl succinic anhydride, and 3-dimethylmethoxysilylpropyl succinic anhydride. Adhesion aid (D) may include adhesion aids other than those listed above.

[0086] The content of the adhesion aid (D) in the positive-type photosensitive resin composition 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, per 100 parts by mass of the biphenyl-type phenolic resin (A1).

[0087] 1.8. Surfactants The positive-type photosensitive resin composition according to this embodiment may contain a surfactant. By including a surfactant, wettability during coating can be improved, and a uniform coating film and resin film can be obtained. Examples of surfactants include fluorine-based surfactants, silicone-based surfactants, alkyl-based surfactants, and acrylic-based surfactants.

[0088] The surfactant preferably contains at least one of a fluorine atom and a silicon atom. This contributes to obtaining a uniform coating film (improved coatability), improved developability, and improved adhesive strength. Such a surfactant is preferably a nonionic surfactant containing at least one of a fluorine atom and a silicon atom. Examples of commercially available surfactants that can be used are, for example, the "MegaFac®" series from DIC Corporation: 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, F Examples include fluorine-containing oligomeric surfactants such as -568, 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 F-568 and F-568, R-40-LM; and silicone-based surfactants such as the SILFOAM® series (e.g., SD 100 TS, SD 670, SD 850, SD 860, SD 882) from Wacker Chemie.

[0089] The positive-type photosensitive resin composition may contain one or more surfactants. The surfactant content in the positive-type photosensitive resin composition is preferably 0.001 to 1 part by mass, and more preferably 0.005 to 0.5 parts by mass, per 100 parts by mass of biphenyl-type phenolic resin (A1).

[0090] 1.9. Solvents The positive-type photosensitive resin composition according to this embodiment preferably contains a solvent. This allows for easy formation of a photosensitive resin film even on stepped substrates by coating. The inclusion of a solvent yields a varnish-like positive-type photosensitive resin composition.

[0091] The solvent typically includes organic solvents. The organic solvent is not particularly limited, as long as it is capable of dissolving or dispersing each of the above-mentioned components and does not substantially react with each of the components.

[0092] 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 monobutyl 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 individually or in combination.

[0093] When a solvent is used, the concentration of the non-volatile component in the positive-type photosensitive resin composition is preferably 30 to 75% by mass, more preferably 35 to 70% by mass. This range allows for sufficient dissolution or dispersion of each component. It also ensures good coatability, leading to improved flatness during spin coating, for example. Furthermore, the viscosity of the positive-type photosensitive resin composition can be appropriately controlled by adjusting the content of the non-volatile component.

[0094] 1.10. Other Ingredients The positive-type photosensitive resin composition according to this embodiment may contain other components in addition to the above components, as needed. Examples of other components include antioxidants, fillers such as silica, sensitizers, and film-forming agents.

[0095] 1.11. Physical properties of positive-type photosensitive resin compositions Next, the physical properties of the positive-type photosensitive resin composition will be described.

[0096] 1.11.1. Tensile elongation The positive-type photosensitive resin composition according to this embodiment achieves a tensile elongation of 40% or more in its cured product by containing the above-mentioned components. Preferably, a tensile elongation of 45% or more, and more preferably 50% or more, is achieved. Having such a tensile elongation, the resistance of the resin film composed of the cured product to brittle fracture can be increased. As a result, when the resin film is used in a semiconductor device, the resistance of the semiconductor device to temperature cycling tests can be increased, and a highly reliable semiconductor device can be realized. From the viewpoint of obtaining a more stable resin film, the tensile elongation of the cured product is preferably 90% or less, and more preferably 70% or less.

[0097] The tensile elongation of the cured product of a positive-type photosensitive resin composition can be determined by the following method. First, the positive-type photosensitive resin composition is cured at 220°C for 240 minutes to form a cured film (cured product), and a sample measuring 6.5 mm × 20 mm × 10 μm thick is prepared from the resulting cured film. Next, a tensile test is performed on the sample at 23°C and a test speed of 5 mm / min, in accordance with JIS K 7161:2014, to determine the tensile elongation.

[0098] 1.11.2. Tensile breaking strength The positive-type photosensitive resin composition according to this embodiment, by containing the above-mentioned components, achieves a tensile breaking strength of preferably 100 MPa or more, more preferably 105 MPa or more, and even more preferably 110 MPa or more in the cured product. Having such a tensile breaking strength makes it possible to further enhance the resistance of the resin film composed of the cured product to brittle fracture. From the viewpoint of obtaining a more stable resin film, the tensile breaking strength of the cured product is preferably 200 MPa or less, and more preferably 150 MPa or less.

[0099] The tensile breaking strength of a cured positive-type photosensitive resin composition can be determined by the following method. First, a positive-type photosensitive resin composition is cured at 220°C for 240 minutes to form a cured film (cured product), and a sample measuring 6.5 mm × 20 mm × 10 μm thick is prepared from the resulting cured film. Next, a tensile test is performed on the sample at 23°C and a test speed of 5 mm / min, in accordance with JIS K 7161:2014, to determine the tensile breaking strength.

[0100] 1.11.3. Glass transition temperature The positive-type photosensitive resin composition according to this embodiment, by containing the above-mentioned components, achieves a glass transition temperature (Tg) of preferably 200°C or higher, more preferably 220°C or higher, in the cured product. Having such a glass transition temperature enhances the deformation resistance of the resin film composed of the cured product to temperature changes. From the viewpoint of obtaining a more stable resin film, the glass transition temperature of the cured product is preferably 300°C or lower, more preferably 260°C or lower.

[0101] The glass transition temperature of the cured product of a positive-type photosensitive resin composition can be determined by the following method.

[0102] First, a positive-type photosensitive resin composition is cured at 220°C for 240 minutes to form a cured film (cured product), and a sample measuring 3 mm × 10 mm × 10 μm thick is prepared from the obtained cured film. Next, measurements are taken using a thermomechanical analyzer (TMA) under the conditions of a starting temperature of 30°C, a measurement temperature range of 30 to 440°C, and a heating rate of 10°C / min, and the glass transition temperature is determined from the measurement results.

[0103] 1.11.4. Coefficient of linear expansion The positive-type photosensitive resin composition according to this embodiment, by containing the above-mentioned components, achieves a coefficient of linear expansion (CTE) of 65 ppm / °C or less, more preferably 60 ppm / °C or less, in the cured product. Having such a coefficient of linear expansion ensures good adhesion of the resin film formed from the cured product to a substrate or the like. From the viewpoint of obtaining a more stable resin film, the coefficient of linear expansion of the cured product is preferably 20 ppm / °C or more, more preferably 25 ppm / °C or more.

[0104] The coefficient of linear thermal expansion of the cured product of a positive-type photosensitive resin composition can be determined by the following method. First, a positive-type photosensitive resin composition is cured at 220°C for 240 minutes to form a cured film (cured product), and a sample measuring 3 mm × 10 mm × 10 μm thick is prepared from the obtained cured film. Next, measurements are performed using a thermomechanical analyzer (TMA) under the conditions of a starting temperature of 30°C, a measurement temperature range of 30 to 440°C, and a heating rate of 10°C / min, and the coefficient of linear expansion in the temperature range of 50 to 100°C is determined from the measurement results.

[0105] 2.Cured film Next, the cured film according to the embodiment will be described.

[0106] A cured product is obtained by drying or curing the positive-type photosensitive resin composition according to this embodiment. The cured film according to this embodiment is composed of this cured product. Such a cured film is used as a resin film in semiconductor devices. The resin film is used in semiconductor devices, for example, as a permanent film or a resist. Of these, it is preferable to use it as a permanent film from the viewpoint of having high elongation and resistance to brittle fracture. Examples of permanent films include protective films such as buffer coat films, interlayer films such as redistribution insulating films, and dam materials.

[0107] The permanent film described above is composed of a cured film obtained by, for example, pre-baking, exposing, and developing a positive-type photosensitive resin composition, patterning it into a desired shape, and then post-baking it.

[0108] Furthermore, the resist described above is composed of a cured film obtained by, for example, applying a positive-type photosensitive resin composition to an object to be masked by the resist using methods such as spin coating, roll coating, flow coating, dip coating, spray coating, or doctor coating, and then removing the solvent from the coated film.

[0109] 3. Semiconductor equipment Next, a semiconductor device according to an embodiment will be described. Figure 1 is a cross-sectional view showing a semiconductor device (semiconductor device according to the embodiment) equipped with a resin film according to the embodiment.

[0110] The semiconductor device 100 shown in Figure 1 includes the resin film described above. Specifically, the resin film is used in one or more components of the semiconductor device 100, selected from the group consisting of a passivation film 32, an insulating layer 42, and an insulating layer 44. Because the resin film has excellent resistance to brittle fracture, a highly reliable semiconductor device 100 can be obtained.

[0111] The semiconductor device 100 is, for example, a semiconductor chip. In this case, a semiconductor package is obtained by mounting the semiconductor device 100 on a wiring substrate via bumps 52. The semiconductor device 100 shown in Figure 1 comprises a semiconductor substrate (not shown) on which semiconductor elements such as transistors are provided, a multilayer wiring layer including an interlayer insulating film 30 and an uppermost wiring layer 34 provided on the semiconductor substrate, a passivation film 32, a redistribution layer 40, a UBM layer 50, and bumps 52.

[0112] The interlayer insulating film 30 and the uppermost wiring 34 are located at the top of the multilayer wiring layer. The uppermost wiring 34 is made of, for example, aluminum. A passivation film 32 is provided on the interlayer insulating film 30 and on the uppermost wiring 34. An opening is provided in a part of the passivation film 32, exposing the uppermost wiring 34.

[0113] A rewiring layer 40 is provided on the passivation film 32. The rewiring layer 40 includes an insulating layer 42 provided on the passivation film 32, rewiring 46 provided on the insulating layer 42, and an insulating layer 44 provided on the insulating layer 42 and the rewiring 46. The insulating layer 42 has openings formed therein that connect to the uppermost wiring 34. The rewiring 46 is formed on the insulating layer 42 and within the openings provided in the insulating layer 42 and is connected to the uppermost wiring 34. The insulating layer 44 has openings that connect to the rewiring 46.

[0114] Bumps 52 are formed within the openings provided in the insulating layer 44 via the UBM layer 50 (Under Bump Metallurgy). The semiconductor device 100 is connected to a wiring board or the like via the bumps 52.

[0115] 4. Effects achieved by the above embodiment As described above, the positive-type photosensitive resin composition according to the embodiment comprises a biphenyl-type phenolic resin (A1), a urea resin-based crosslinking agent (B1), and a photosensitive agent (C). The urea resin-based crosslinking agent (B1) mainly consists of a bifunctional or trifunctional compound. Furthermore, the tensile elongation of the cured product is 40% or more.

[0116] This configuration yields a positive-type photosensitive resin composition capable of producing resin films with excellent resistance to brittle fracture. As a result, when the resin film is used in a semiconductor device, its resistance to temperature cycling tests can be enhanced, enabling the realization of a highly reliable semiconductor device.

[0117] Furthermore, the urea resin-based crosslinking agent (B1) preferably further contains a tetrafunctional compound. This configuration yields a cured product that combines a flexible structure derived from a bifunctional compound with a rigid structure derived from a tetrafunctional compound. Therefore, while suppressing the decrease in elongation and mechanical strength of the cured product, the rigid structure allows for an increased glass transition temperature. As a result, a resin film with excellent deformation resistance (heat resistance) at high temperatures is obtained.

[0118] Furthermore, when such a resin film is used, for example, in the fabrication of a redistribution layer, it contributes to reducing the thickness of the oxide film that forms on the surface of the wiring. This makes it possible to suppress the occurrence of warping of the semiconductor wafer that is caused by the thickness of the oxide film.

[0119] Furthermore, such resin films are thought to contribute to suppressing the occurrence of voids and cracks at the interface with the wiring. By suppressing the occurrence of voids and other defects, the reliability of the rewiring layer is improved.

[0120] Furthermore, the urea resin-based crosslinking agent (B1) preferably has an average number of functional groups per molecule of 1.5 or more and 3.5 or less.

[0121] This configuration allows for particularly high elongation of the cured product of the positive-type photosensitive resin composition, as well as increased tensile strength and glass transition temperature of the cured product. Furthermore, it enables the creation of a resin film with particularly low oxygen permeability while maintaining high elongation and mechanical strength of the cured product. In addition, it can suppress the generation of voids and other defects at the interface between the wiring portion and the oxide film.

[0122] Furthermore, the positive-type photosensitive resin composition according to the above embodiment preferably contains an epoxy resin-based crosslinking agent (B2).

[0123] This configuration allows for the imparting of flexibility to the cured product of the positive-type photosensitive resin composition. As a result, the elongation of the cured product can be increased without compromising its tensile strength.

[0124] Furthermore, it is preferable that the content of the urea resin-based crosslinking agent (B1) is greater than the content of the epoxy resin-based crosslinking agent (B2).

[0125] This configuration achieves both the effect of increasing the elongation of the cured material and the effect of ensuring tensile fracture strength. As a result, a cured material with excellent resistance to temperature cycling tests can be obtained.

[0126] Furthermore, it is preferable that the positive-type photosensitive resin composition according to the above embodiment has a glass transition temperature of 200°C or higher and 300°C or lower for the cured product.

[0127] This configuration makes it possible to improve the deformation resistance of the resin film composed of the cured material to temperature changes.

[0128] Furthermore, the positive-type photosensitive resin composition according to the above embodiment preferably further contains an adhesion aid (D).

[0129] With this configuration, for example, the adhesion between the cured product of a positive-type photosensitive resin composition and the substrate can be further improved.

[0130] Furthermore, the cured film according to the embodiment is composed of a cured product of the positive-type photosensitive resin composition according to the embodiment. With this configuration, a hardened film with excellent resistance to brittle fracture can be obtained.

[0131] Furthermore, the semiconductor device according to the above embodiment comprises a semiconductor element and a resin film provided on the surface of the semiconductor element. The resin film includes a cured film according to the above embodiment.

[0132] With this configuration, the resin film exhibits excellent resistance to brittle fracture, resulting in a highly reliable semiconductor device.

[0133] Although the positive-type photosensitive resin composition, cured film, and semiconductor device according to the present invention have been described above based on the embodiments, the present invention is not limited to the embodiments described above. For example, the positive-type photosensitive resin composition, cured film, and semiconductor device according to the present invention may be in which each part of the embodiments described above is replaced with any configuration having a similar function, or any configuration may be added to the embodiments described above. [Examples]

[0134] Next, specific embodiments of the present invention will be described. 5. Preparation of positive-type photosensitive resin composition 5.1. Example 1 A varnish-like positive-type photosensitive resin composition was prepared by stirring and mixing each component shown in Table 1 under a nitrogen atmosphere, followed by filtration through a polyethylene filter with a pore size of 0.2 μm. Details of each component listed in Table 1 are as follows.

[0135] 5.1.1. Components • Biphenyl-type phenolic resin a1-1: A biphenyl-type phenolic resin having the structure represented by the following formula (a1-1), manufactured by Sumitomo Bakelite Co., Ltd., PR-X21024, Mw=45,000

[0136] [ka]

[0137] Method for producing biphenyl-type phenolic resin a1-1 In a four-necked glass round-bottom flask equipped with a thermometer, stirrer, raw material inlet, and dry nitrogen gas inlet tube, 186.2 g (1.00 mol) of 4,4'-biphenol, 86.5 g (0.8 mol) of p-cresol, 28.5 g (0.94 mol) of formaldehyde, 15.5 g (0.09 mol) of p-toluenesulfonic acid, and 308 g of γ-butyrolactone were charged. A polycondensation reaction was then carried out at 100°C for 5.5 hours while flowing nitrogen through the flask and refluxing the reaction mixture in an oil bath. Next, the resulting reaction mixture was cooled to room temperature, and 411 g of acetone was added and stirred until homogeneous. Subsequently, the resin component was precipitated by adding the reaction mixture in the round-bottom flask dropwise to 10 L of water and mixing. Next, the precipitated resin components were filtered and recovered, and then vacuum-dried at 60°C to obtain a biphenyl-type phenolic resin having the structure represented by the above formula (a1-1). The weight-average molecular weight of the obtained biphenyl-type phenolic resin (a1-1) was 45,000.

[0138] • Biphenyl-type phenolic resin a1-2: A biphenyl-type phenolic resin having the structure represented by the following formula (a1-2), manufactured by Sumitomo Bakelite Co., Ltd., Mw = 45,000

[0139] [ka]

[0140] Method for producing biphenyl-type phenolic resin a1-2 In a four-necked glass round-bottom flask equipped with a thermometer, stirrer, raw material inlet, and dry nitrogen gas inlet tube, 186.2 g (1.00 mol) of 4,4'-biphenol, 86.5 g (0.8 mol) of p-cresol, 24.0 g (0.8 mol) of formaldehyde, 11.3 g (0.09 mol) of oxalic acid dihydrate, and 308 g of γ-butyrolactone were charged. A polycondensation reaction was then carried out at 100°C for 6 hours while flowing nitrogen through the flask and refluxing the reaction mixture in an oil bath. Next, the resulting reaction mixture was cooled to room temperature, and 411 g of acetone was added and stirred until homogeneous. Subsequently, the resin component was precipitated by adding the reaction mixture in the round-bottom flask dropwise to 10 L of water and mixing. Next, the precipitated resin components were filtered and recovered, and then vacuum-dried at 60°C to obtain a biphenyl-type phenolic resin having the structure represented by the above formula (a1-2). The weight-average molecular weight of the obtained biphenyl-type phenolic resin (a1-2) was 11,000.

[0141] • Urea resin crosslinking agent b1-1 (tetrafunctional compound): 1,3,4,6-tetrakis(methoxymethyl) glycoluryl, manufactured by Daito Chemix, Crolin-318 • Urea resin crosslinking agent b1-2 (tetrafunctional compound): 1,3,4,6-tetrakis(butoxymethyl) glycoluryl, manufactured by Sanwa Chemical Co., Ltd., Nikalac (registered trademark) MX-279 • Urea resin-based crosslinking agent b1-3 (trifunctional compound): Trimethoxymethylated glycol uryl • Urea resin crosslinking agent b1-4 (bifunctional compound): 1,3-bis(methoxymethyl)-4,5-dimethoxy-2-imidazolidinone, manufactured by Sanwa Chemical Co., Ltd., Nikalac MX-280 • Urea resin crosslinking agent b1-5 (bifunctional compound): 1,3-bis(methoxymethyl)urea, manufactured by Sanwa Chemical Co., Ltd., Nikalac MX-290

[0142] • Epoxy resin crosslinking agent b2-1: Phenoxy-type epoxy resin, manufactured by Mitsubishi Chemical Corporation, YX-7105 • Epoxy resin crosslinking agent b2-2: Epoxy resin (bisphenol A type phenoxy resin), manufactured by Mitsubishi Chemical Corporation, JER-1256 • Epoxy resin crosslinking agent b2-3: Bisphenol A type epoxy resin, manufactured by Osaka Soda Co., Ltd., LX-01

[0143] • Thermal acid generator c1-1: Compound represented by the following formula (c1-1) (manufactured by Sanshin Chemical Industry Co., Ltd., San-Aid SI-B3A)

[0144] [ka]

[0145] • Thermal acid generator c1-2: Compound represented by the following formula (c1-2) (manufactured by Sanshin Chemical Industry Co., Ltd., San-Aid SI-150)

[0146] [ka]

[0147] • Photoacid generator c2-1: 3-diazo-3,4-dihydro-4-oxo-1-naphthalene sulfonate of 4,4'-(1-{4-[1-(4-hydroxyphenyl)-1-methylethyl]phenyl}ethylidene)diphenol, manufactured by Daito Chemix, DS-427

[0148] • Adhesion enhancer 1:3-Glycidoxypropyltrimethoxysilane, manufactured by Shin-Etsu Chemical Co., Ltd., KBM-403E Solvent 1: γ-butyrolactone, manufactured by Sanwa Oil & Chemical Industries Co., Ltd. Table 1 shows the average number of functional groups per molecule in the urea resin-based crosslinking agent (B1).

[0149] 5.1.2. Physical Properties The following physical properties were measured for the prepared positive-type photosensitive resin composition.

[0150] • Tensile elongation Samples were prepared from the obtained positive-type photosensitive resin composition using the method described above. Tensile tests were performed on the prepared samples using an Orientec tensile testing machine (Tensilon RTA-100). Eight tests were performed on each sample, and the average value of the tensile elongation was calculated. The calculated results are shown in Table 1 as tensile elongation values.

[0151] • Tensile breaking strength Samples were prepared from the obtained positive-type photosensitive resin composition using the method described above. Tensile tests were performed on the prepared samples using an Orientec tensile testing machine (Tensilon RTC-1210A). The strength at which the sample broke was defined as the tensile breaking strength, and the measurement results are shown in Table 1.

[0152] • Glass transition temperature (Tg) and coefficient of linear thermal expansion (CTE) Samples were prepared from the obtained positive-type photosensitive resin composition using the method described above. Thermomechanical analysis was performed on the prepared samples using a thermomechanical analyzer (TMA, Seiko Instruments, SS6000). From the analysis results, the Tg (°C) and the coefficient of linear expansion (ppm / °C) in the temperature range of 50 to 100°C were determined. The measurement results are shown in Table 1.

[0153] • Development The obtained positive-type photosensitive resin compositions were each coated onto an 8-inch silicon wafer using a spin coater. The resulting coated films were then pre-baked on a hot plate at 100°C for 4 minutes to obtain a coating with a thickness of approximately 6.0 μm. This coating was then irradiated using an i-line stepper (Nikon NSR-4425i) with varying exposure levels, passing through a Toppan Printing Co., Ltd. mask (Test Chart No. 1: with remaining and cut-out patterns ranging from 0.88 to 50 μm in width).

[0154] Next, using a 2.38% aqueous tetramethylammonium hydroxide solution as the developer, two paddle development cycles were performed, adjusting the development time so that the difference between the film thickness after pre-baking and after development was 1.0 μm. After dissolving and removing the exposed areas, the film was rinsed with pure water for 10 seconds. The minimum exposure level for forming a 100 μm square via hole pattern was +100 mJ / cm². 2 The resolution of the line pattern was evaluated using a pattern exposed with the specified energy. Resolution was determined by checking whether the line pattern was open at 10 μm intervals. If it was open, it was marked with "○"; if it was not open, it was marked with "×" as shown in Table 1.

[0155] 5.2. Examples 2-14 and Comparative Examples 1-3 A positive-type photosensitive resin composition was prepared in the same manner as in Example 1, except that the constituent components were as shown in Table 1 or Table 2, and its physical properties were measured. The measurement results are shown in Tables 1 and 2.

[0156] 5.3. Comparative Example 4 A positive-type photosensitive resin composition was prepared in the same manner as in Example 1, except that the constituent components were as shown in Table 3, and the tensile elongation was measured. The measurement results are shown in Table 3.

[0157] 6. Temperature cycling test (TC) The positive-type photosensitive resin compositions obtained in each example were coated onto an 8-inch silicon wafer using a spin coater. The resulting coated film was then cured at 220°C for 240 minutes to obtain a cured film (resin film). Next, the obtained cured film was subjected to a temperature cycle test (TC) 200 times under atmospheric pressure air conditions, with a temperature of -65 to 150°C and a stop time of 15 minutes, with -65°C as the start and end temperature. After this, the cured film was cut into a grid pattern using the cross-cut method specified in JIS K 5600-5-6. A tape peel test was performed on the grid-cut cured film, and the percentage of the grid (cured film) adhering to the wafer (adhesion rate) was calculated. The calculated adhesion rate was then evaluated according to the following evaluation criteria. The evaluation results are shown in Tables 1 to 3.

[0158] A: The adhesion rate is 100%. B: The adhesion rate is 75% or more but less than 100%. C: The adhesion rate is less than 75%.

[0159] 7. High-Temperature Storage Test (HTS) 7.1. Thickness of copper oxide film after high-temperature storage test The positive-type photosensitive resin compositions obtained in each example were coated onto silicon wafers on which Test Element Groups (TEGs) were formed using a spin coater. The resulting coated films were then cured at 220°C for 240 minutes to obtain resin films. Next, the obtained resin films were subjected to high-temperature storage tests (HTS) in which they were stored at 150°C for 500 or 1000 hours under atmospheric pressure. After that, the silicon wafers were cut, the cross-sections were polished, and the cross-sections of the redistribution layers were observed using a scanning electron microscope.

[0160] Next, the thickness of the copper oxide film formed at the interface between the copper wiring and the resin film was measured in the observed image. The thickness of the copper oxide film was determined by identifying the film formed at the interface between the copper wiring and the resin film based on the difference in contrast in the observed image, and then averaging the thickness of that film measured at 10 or more locations. The obtained thickness was then evaluated according to the following evaluation criteria. The evaluation results are shown in Tables 1 to 3.

[0161] A: The thickness of the copper oxide film is 15 μm or less. B: The thickness of the copper oxide film is greater than 15 μm and less than or equal to 17 μm. C: The thickness of the copper oxide film is greater than 17 μm.

[0162] 7.2. Interface between copper wiring and copper oxide film after high-temperature storage test In the observation images obtained in 7.1, the interface between the copper wiring and the copper oxide film was evaluated according to the following evaluation criteria. The evaluation results are shown in Tables 1 to 3.

[0163] A: No cracks are present at the interface, and the maximum diameter of voids at the interface is 20 μm or less. B: No cracks are present at the interface, and the maximum diameter of the interface void is greater than 20 μm and less than or equal to 30 μm. C: Cracks are present at the interface, or the maximum diameter of the void at the interface is greater than 30 μm.

[0164] [Table 1]

[0165] [Table 2]

[0166] [Table 3]

[0167] As shown in Tables 1 to 3, the positive-type photosensitive resin compositions of each example were found to have high tensile elongation of the cured product. Furthermore, it was found that by optimizing the crosslinking agent formulation, it was possible to increase both the tensile elongation and the tensile breaking strength and glass transition temperature. In addition, it was found that by using the positive-type photosensitive resin compositions of each example, it was possible to realize a cured film (resin film) with high resistance to temperature cycling tests.

[0168] Furthermore, it was found that when the resin films produced using the positive-type photosensitive resin compositions of each embodiment were used to produce a redistribution layer, they effectively suppressed the thickness of the copper oxide film formed on the surface of the copper wiring portion, and also suppressed the occurrence of voids and cracks at the interface between the copper wiring portion and the copper oxide film.

[0169] Figure 2 is a magnified view showing the interface between the copper wiring portion and the copper oxide film, fabricated using the positive-type photosensitive resin composition of Example 1. Figure 3 is a magnified view showing the interface between the copper wiring portion and the copper oxide film, fabricated using the positive-type photosensitive resin composition of Comparative Example 4.

[0170] Figure 2 shows that there are almost no voids at the interface between the copper wiring and the copper oxide film, and the size of the voids is sufficiently small. In contrast, Figure 3 shows that there are many voids at the interface between the copper wiring and the copper oxide film, and the size of the voids is relatively large. [Industrial applicability]

[0171] According to the present invention, a positive-type photosensitive resin composition capable of producing resin films with excellent resistance to brittle fracture can be obtained. Furthermore, according to the present invention, highly reliable cured films and semiconductor devices can be obtained. Therefore, the present invention has industrial applicability. [Explanation of Symbols]

[0172] 30 Interlayer insulating film 32 Passivation membrane 34 Top layer wiring 40 Redistribution layer 42 Insulating layer 44 Insulating layer 46 Rewiring 50 UBM layers 52 Bump 100 Semiconductor Equipment

Claims

1. A positive-type photosensitive resin composition used in resin films for semiconductor devices, Biphenyl-type phenolic resin (A1), Urea resin-based crosslinking agent (B1), Photosensitive material (C), Includes, The urea resin crosslinking agent (B1) mainly consists of a bifunctional compound or a trifunctional compound. A positive-type photosensitive resin composition characterized in that the tensile elongation of the cured product of the positive-type photosensitive resin composition is 40% or more.

2. The positive-type photosensitive resin composition according to claim 1, further comprising a tetrafunctional compound as the urea resin-based crosslinking agent (B1).

3. The positive-type photosensitive resin composition according to claim 1 or 2, wherein the urea resin-based crosslinking agent (B1) has an average number of functional groups per molecule of 1.5 or more and 3.5 or less.

4. The positive-type photosensitive resin composition according to claim 1 or 2, further comprising an epoxy resin-based crosslinking agent (B2).

5. The positive-type photosensitive resin composition according to claim 4, wherein the content of the urea resin-based crosslinking agent (B1) is greater than the content of the epoxy resin-based crosslinking agent (B2).

6. The positive-type photosensitive resin composition according to claim 1 or 2, wherein the glass transition temperature of the cured product is 200°C or more and 300°C or less.

7. The positive-type photosensitive resin composition according to claim 1 or 2, further comprising an adhesion aid (D).

8. A cured film characterized by being composed of a cured product of the positive-type photosensitive resin composition described in claim 1 or 2.

9. Semiconductor elements and A resin film provided on the surface of the semiconductor element, Equipped with, The semiconductor device is characterized in that the resin film includes the cured film described in claim 8.

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