JP7796511B2 - Negative photosensitive resin composition, dry film, cured product, and electronic component - Google Patents

Description

The present invention relates to a negative-type photosensitive resin composition, including a negative-type photosensitive resin composition containing polyamic acid as a photosensitive component, a dry film having a resin layer formed by applying and drying the negative-type photosensitive resin composition, a cured product of the negative-type photosensitive resin composition or resin layer, and an electronic component having the cured product.

Conventionally, photosensitive resin compositions primarily composed of polyamic acid or polyhydroxyamide, precursors to polyimide or polybenzoxazole, have been used as insulating materials for rewiring in semiconductor elements. These polyamic acid or polyhydroxyamide undergo a cyclization reaction to form imide rings or benzoxazole rings when heated at high temperatures (over 350°C), resulting in a rigid structure that increases the intermolecular packing density, resulting in a cured film with excellent chemical resistance and thermal properties.

On the other hand, a so-called chip-first fan-out wafer-level packaging method is known, in which rewiring is formed after the chip is sealed with a sealant whose main component is epoxy resin. The insulating material for the rewiring used in this method must be able to cure at temperatures of around 220°C, given the heat resistance of epoxy resins. Therefore, methods are being investigated that can produce cured products that meet the chemical and heat resistance requirements of a cured film even at relatively low temperatures. For example, various approaches have been proposed, such as adding a crosslinking agent such as an epoxy compound to a photosensitive resin composition containing polyamic acid or polyhydroxyamide (Patent Document 1).

In addition, positive-tone photosensitive resin compositions, such as the resin composition described in Patent Document 1, are widely used in insulating materials used in semiconductor elements from the perspectives of fine patterning and flexibility. Meanwhile, in recent years, interest has also been growing in negative-tone photosensitive resin compositions, which offer excellent adhesion, chemical resistance, film thickness, and pattern shape, in order to accommodate the increasingly complex structures and manufacturing processes of semiconductor elements.

JP 2014-111718 A

When negative-tone photosensitive resin compositions are used as insulating materials for semiconductor elements, they must not only have the conventional properties of heat resistance, electrical properties, mechanical properties, etc., but also the same fine patterning and flexibility as positive-tone photosensitive resin compositions.

Therefore, the primary object of the present invention is to provide a negative-tone photosensitive resin composition that provides a cured product with excellent resolution and flexibility. Another object of the present invention is to provide a dry film having a resin layer formed by applying and drying the negative-tone photosensitive resin composition, a cured product of the negative-tone photosensitive resin composition or resin layer, and an electronic component having the cured product.

The inventors of the present invention have focused on negative-tone photosensitive resin compositions using polyamic acid, a precursor to polyimide, which has excellent properties such as heat resistance and flexibility, and have conducted extensive research. As a result, they have discovered that by photoradical polymerizing a polyamic acid having a specific molecular weight and an unsaturated carbon bond at the molecular chain end with a crosslinker having a specific thiol group using a specific photosensitizer, it is possible to obtain a cured product with improved resolution and excellent flexibility. The present invention was completed based on this discovery. The gist of the present invention is as follows.

[1] (A) an alkali-soluble resin;
(B) a photosensitizer;
(C) a crosslinking agent;
A negative photosensitive resin composition comprising:
The alkali-soluble resin (A) is represented by the following formula (1):
(In general formula (1), X represents a tetravalent organic group, Y represents a divalent organic group, and n represents an integer.)
and a polyamic acid having a number average molecular weight of less than 20,000, which has a repeating unit represented by the formula:
the (B) photosensitizer contains an oxime-based photopolymerization initiator,
the (C) crosslinking agent contains a polyfunctional primary thiol compound having two or more functional thiol groups in one molecule;
A negative photosensitive resin composition comprising:
[2] The negative photosensitive resin composition according to [1], wherein the polyamic acid is derived from a compound in which an unsaturated carbon bond at a molecular chain terminal has a norbornene structure.
[3] The negative photosensitive resin composition according to [1] or [2], wherein the polyfunctional primary thiol compound has 2 to 6 thiol groups in one molecule.
[4] The negative photosensitive resin composition according to any one of [1] to [3], wherein at least one organic group of X and Y in the formula (1) has an ether bond (—O—).
[5] The negative photosensitive resin composition according to any one of [1] to [4], wherein the polyamic acid has a number average molecular weight of more than 4,000 and not more than 10,000.
[6] A dry film comprising a base film and a resin layer provided on at least one side of the base film,
A dry film, characterized in that the resin layer is a coating and drying product of the negative photosensitive resin composition according to any one of [1] to [5].
[7] A cured product of the negative photosensitive resin composition according to any one of [1] to [5] or the resin layer of the dry film according to [6].
[8] An electronic component comprising the cured product according to [7].

The present invention makes it possible to realize a negative-tone photosensitive resin composition that produces a cured product with excellent resolution and flexibility.

Modes for carrying out the invention

[Negative Photosensitive Resin Composition]
The negative-type photosensitive resin composition according to the present invention contains, as essential components, (A) an alkali-soluble resin, (B) a photosensitizer, and (C) a crosslinker. By using, as the (A) alkali-soluble resin, a polyamic acid having a specific molecular weight (a number-average molecular weight of less than 20,000) and having an unsaturated carbon bond at at least one molecular chain terminal, as the (A) alkali-soluble resin, an oxime-based photopolymerization initiator as the (B) photosensitizer, and a polyfunctional primary thiol compound as the (C) crosslinker, it is possible to impart flexibility to the resulting cured product while improving resolution.
The reason for this is unclear, but is thought to be as follows. The photosensitive resin composition of the present invention is a negative-tone photosensitive resin composition that generates radical active species upon exposure, which then induces a thiol-ene reaction between the terminal unsaturated carbon bonds of the polyamic acid and the thiol groups of the crosslinking agent, dissolving the unexposed areas in a developer to form a pattern. Furthermore, the use of a polyfunctional primary thiol compound as the crosslinking agent suppresses steric hindrance at the crosslinked sites, imparting excellent flexibility to the resulting cured product. Meanwhile, the primary thiol groups contained in the crosslinking agent are inhibited by oxygen, making it difficult to promote crosslinking reactions and achieve sufficient development resistance after exposure. Therefore, the use of an oxime-based photopolymerization initiator and a polyamic acid with a relatively small molecular weight in the present invention is believed to enable both excellent resolution and flexibility as a cured product, even when a polyfunctional primary thiol compound is used as the crosslinking agent. The components of the negative-tone photosensitive resin composition of the present invention are described in detail below.

<(A) Alkali-soluble resin>
The negative-type photosensitive resin composition according to the present invention contains, as a resin component, a polyamic acid having a repeating unit represented by the following formula (1), an unsaturated carbon bond at at least one molecular chain terminal, and a number-average molecular weight of less than 20,000. The polyamic acid is a polyimide precursor, and upon heating, the amic acid in the structure undergoes dehydration ring closure to form an imide ring. The polyamic acid may also be a polybenzoxazole precursor.
(In general formula (1), X represents a tetravalent organic group, Y represents a divalent organic group, and n represents an integer.)

The polyamic acid represented by formula (1) above can be obtained by reacting a carboxylic acid anhydride component with an amine component and/or an isocyanate component using a standard method. That is, it can be obtained by reacting a carboxylic acid anhydride having X as the skeleton with an amine component and/or an isocyanate component having Y as the skeleton. Imidization can be carried out by thermal imidization, chemical imidization, or a combination of these methods.

Carboxylic acid anhydride components include tetracarboxylic acid anhydrides and tricarboxylic acid anhydrides, but are not limited to these acid anhydrides. Any compound containing an acid anhydride group and a carboxyl group that react with an amino group or an isocyanate group, including their derivatives, can be used. Furthermore, these carboxylic acid anhydride components may be used alone or in combination of two or more.

Examples of tetracarboxylic acid anhydrides include pyromellitic dianhydride, 3-fluoropyromellitic dianhydride, 3,6-difluoropyromellitic dianhydride, 3,6-bis(trifluoromethyl)pyromellitic dianhydride, 3,3',4,4'-benzophenonetetracarboxylic acid dianhydride, 3,3',4,4'-biphenyltetracarboxylic acid dianhydride, 4,4'-oxydiphthalic dianhydride, 2,2'-difluoro-3,3',4,4'-biphenyltetracarboxylic acid dianhydride, 5,5'-difluoro-3,3',4,4'-biphenyltetracarboxylic acid dianhydride, 6,6'-difluoro-3,3',4,4'-biphenyltetracarboxylic acid dianhydride, dianhydride, 2,2',5,5',6,6'-hexafluoro-3,3',4,4'-biphenyltetracarboxylic dianhydride, 2,2'-bis(trifluoromethyl)-3,3',4,4'-biphenyltetracarboxylic dianhydride, 5,5'-bis(trifluoromethyl)-3,3',4,4'-biphenyltetracarboxylic dianhydride, 6,6'-bis(trifluoromethyl)-3,3',4,4'-biphenyltetracarboxylic dianhydride, 2,2',5,5'-tetrakis(trifluoromethyl)-3,3',4,4'-biphenyltetracarboxylic dianhydride, 2,2',6,6'-tetrakis(trifluoromethyl)-3,3', 4,4'-biphenyltetracarboxylic dianhydride, 5,5',6,6'-tetrakis(trifluoromethyl)-3,3',4,4'-biphenyltetracarboxylic dianhydride, and 2,2',5,5',6,6'-hexakis(trifluoromethyl)-3,3',4,4'-biphenyltetracarboxylic dianhydride, 1,2,3,4-benzenetetracarboxylic dianhydride, 3,3",4,4"-terphenyltetracarboxylic dianhydride, 3,3'",4,4'"-quaterphenyltetracarboxylic dianhydride, 3,3"",4,4""-quinquephenyltetracarboxylic dianhydride, methylene-4,4'-diphthalic dianhydride, 1,1-ethyl 2,2-propylidene-4,4'-diphthalic dianhydride, 1,2-ethylene-4,4'-diphthalic dianhydride, 1,3-trimethylene-4,4'-diphthalic dianhydride, 1,4-tetramethylene-4,4'-diphthalic dianhydride, 1,5-pentamethylene-4,4'-diphthalic dianhydride, 2,2-bis(3,4-dicarboxyphenyl)-1,1,1,3,3,3-hexafluoropropane dianhydride, difluoromethylene-4,4'-diphthalic dianhydride, 1,1,2,2-tetrafluoro-1,2-ethylene-4,4'-diphthalic dianhydride, 1,1,2,2,3,3-hexafluoro-1 ,3-trimethylene-4,4'-diphthalic dianhydride, 1,1,2,2,3,3,4,4-octafluoro-1,4-tetramethylene-4,4'-diphthalic dianhydride, 1,1,2,2,3,3,4,4,5,5-decafluoro-1,5-pentamethylene-4,4'-diphthalic dianhydride, thio-4,4'-diphthalic dianhydride, sulfonyl-4,4'-diphthalic dianhydride, 1,3-bis(3,4-dicarboxyphenyl)-1,1,3,3-tetramethylsiloxane dianhydride, 1,3-bis(3,4-dicarboxyphenyl)benzene dianhydride, 1,4-bis(3,4-dicarboxyphenyl)benzene dianhydride, 1,3-bis(3 ,4-dicarboxyphenoxy)benzene dianhydride, 1,4-bis(3,4-dicarboxyphenoxy)benzene dianhydride, 1,3-bis[2-(3,4-dicarboxyphenyl)-2-propyl]benzene dianhydride, 1,4-bis[2-(3,4-dicarboxyphenyl)-2-propyl]benzene dianhydride, bis[3-(3,4-dicarboxyphenoxy)phenyl]methane dianhydride, bis[4-(3,4-dicarboxyphenoxy)phenyl]methane dianhydride, 2,2-bis[3-(3,4-dicarboxyphenoxy)phenyl]propane dianhydride, 2,2-bis[4-(3,4-dicarboxyphenoxy)phenyl]propane dianhydride anhydride, 2,2-bis[3-(3,4-dicarboxyphenoxy)phenyl]-1,1,1,3,3,3-hexafluoropropane dianhydride, 2,2-bis[4-(3,4-dicarboxyphenoxy)phenyl]propane dianhydride, bis(3,4-dicarboxyphenoxy)dimethylsilane dianhydride, 1,3-bis(3,4-dicarboxyphenoxy)-1,1,3,3-tetramethyldisiloxane dianhydride, 2,3,6,7-naphthalenetetracarboxylic acid dianhydride, 1,2,5,6-naphthalenetetracarboxylic acid dianhydride, 3,4,9,10-perylenetetracarboxylic acid dianhydride, 2,3,6,7-anthracenetetracarboxylic acid dianhydride hydrate, 1,2,7,8-phenanthrenetetracarboxylic dianhydride, 1,2,3,4-butanetetracarboxylic dianhydride, 1,2,3,4-cyclobutanetetracarboxylic dianhydride, cyclopentanetetracarboxylic dianhydride, cyclohexane-1,2,3,4-tetracarboxylic dianhydride, cyclohexane-1,2,4,5-tetracarboxylic dianhydride, 3,3',4,4'-bicyclohexyltetracarboxylic dianhydride, carbonyl-4,4'-bis(cyclohexane-1,2-dicarboxylic acid) dianhydride, methylene-4,4'-bis(cyclohexane-1,2-dicarboxylic acid) dianhydride, 1,2-ethylene-4,4'-bis(cyclohexane 4,4'-bis(cyclohexane-1,2-dicarboxylic acid) dianhydride, 1,1-ethynylidene-4,4'-bis(cyclohexane-1,2-dicarboxylic acid) dianhydride, 2,2-propylidene-4,4'-bis(cyclohexane-1,2-dicarboxylic acid) dianhydride, 1,1,1,3,3,3-hexafluoro-2,2-propylidene-4,4'-bis(cyclohexane-1,2-dicarboxylic acid) dianhydride, oxy-4,4'-bis(cyclohexane-1,2-dicarboxylic acid) dianhydride, thio-4,4'-bis(cyclohexane-1,2-dicarboxylic acid) dianhydride, sulfonyl-4,4'-bis(cyclohexane-1,2-dicarboxylic acid) dianhydride, 3,3'-difluoro Fluorooxy-4,4'-diphthalic dianhydride, 5,5'-difluorooxy-4,4'-diphthalic dianhydride, 6,6'-difluorooxy-4,4'-diphthalic dianhydride, 3,3',5,5',6,6'-hexafluorooxy-4,4'-diphthalic dianhydride, 3,3'-bis(trifluoromethyl)oxy-4,4'-diphthalic dianhydride, 5,5'-bis(trifluoromethyl)oxy-4,4'-diphthalic dianhydride, 6,6'-bis(trifluoromethyl)oxy-4,4'-diphthalic dianhydride, 3,3',5,5'-tetrakis(trifluoromethyl)oxy-4,4'-diphthalic dianhydride, 3,3',6,6'- Tetrakis(trifluoromethyl)oxy-4,4'-diphthalic dianhydride, 5,5',6,6'-tetrakis(trifluoromethyl)oxy-4,4'-diphthalic dianhydride, 3,3',5,5',6,6'-hexakis(trifluoromethyl)oxy-4,4'-diphthalic dianhydride, 3,3'-difluorosulfonyl-4,4'-diphthalic dianhydride, 5,5'-difluorosulfonyl-4,4'-diphthalic dianhydride, 6,6'-difluorosulfonyl-4,4'-diphthalic dianhydride, 3,3',5,5',6,6'-hexafluorosulfonyl-4,4'-diphthalic dianhydride, 3,3'-bis(trifluoromethyl)sulfonyl bis(trifluoromethyl)sulfonyl-4,4'-diphthalic dianhydride, 5,5'-bis(trifluoromethyl)sulfonyl-4,4'-diphthalic dianhydride, 6,6'-bis(trifluoromethyl)sulfonyl-4,4'-diphthalic dianhydride, 3,3',5,5'-tetrakis(trifluoromethyl)sulfonyl-4,4'-diphthalic dianhydride, 3,3',6,6'-tetrakis(trifluoromethyl)sulfonyl-4,4'-diphthalic dianhydride, 5,5',6,6'-tetrakis(trifluoromethyl)sulfonyl-4,4'-diphthalic dianhydride, 3,3',5,5',6,6'-hexakis(trifluoromethyl)sulfonyl-4,4'-diphthalic dianhydride Fluorocarbons, 3,3'-difluoro-2,2-perfluoropropylidene-4,4'-diphthalic dianhydride, 5,5'-difluoro-2,2-perfluoropropylidene-4,4'-diphthalic dianhydride, 6,6'-difluoro-2,2-perfluoropropylidene-4,4'-diphthalic dianhydride, 3,3',5,5',6,6'-hexafluoro-2,2-perfluoropropylidene-4,4'-diphthalic dianhydride, 3,3'-bis(trifluoromethyl)-2,2-perfluoropropylidene-4,4'-diphthalic dianhydride, 5,5'-bis(trifluoromethyl)-2,2-perfluoropropylidene-4,4'-diphthalic dianhydride Aqueous solution, 6,6'-difluoro-2,2-perfluoropropylidene-4,4'-diphthalic dianhydride, 3,3',5,5'-tetrakis(trifluoromethyl)-2,2-perfluoropropylidene-4,4'-diphthalic dianhydride, 3,3',6,6'-tetrakis(trifluoromethyl)-2,2-perfluoropropylidene-4,4'-diphthalic dianhydride, 5,5',6,6'-tetrakis(trifluoromethyl)-2,2-perfluoropropylidene-4,4'-diphthalic dianhydride, 3,3',5,5',6,6'-hexakis(trifluoromethyl)-2,2-perfluoropropylidene-4,4'-diphthalic dianhydride, 9-phenyl-9-(trifluoromethyl)xanthene-2,3,6,7-tetracarboxylic dianhydride, 9,9-bis(trifluoromethyl)xanthene-2,3,6,7-tetracarboxylic dianhydride, bicyclo[2,2,2]oct-7-ene-2,3,5,6-tetracarboxylic dianhydride, 9,9-bis[4-(3,4-dicarboxy)phenyl]fluorene dianhydride, 9,9-bis[4-(2,3-dicarboxy)phenyl]fluorene dianhydride, ethylene glycol bistrimellitate dianhydride, 1,2-(ethylene)bis(trimellitate anhydride), 1,3-(trimethylene)bis(trimellitate anhydride), 1,4-(tetramethylphenyl) Examples include 1,5-(pentamethylene)bis(trimellitate anhydride), 1,6-(hexamethylene)bis(trimellitate anhydride), 1,7-(heptamethylene)bis(trimellitate anhydride), 1,8-(octamethylene)bis(trimellitate anhydride), 1,9-(nonamethylene)bis(trimellitate anhydride), 1,10-(decamethylene)bis(trimellitate anhydride), 1,12-(dodecamethylene)bis(trimellitate anhydride), 1,16-(hexadecamethylene)bis(trimellitate anhydride), and 1,18-(octadecamethylene)bis(trimellitate anhydride).

Of the tetracarboxylic acid anhydrides listed above, those containing an ether bond (-O-) within the molecule, such as 4,4'-oxydiphthalic anhydride (ODPA), 4,4'-(4,4'-isopropylidenediphenoxy)diphthalic dianhydride (BPADA), and 2,2-bis[4-(4-aminophenoxy)phenyl]propane (BAPP), are preferred from the standpoint of flexibility of the cured product.

Examples of tricarboxylic acid anhydrides include trimellitic anhydride and nuclear-hydrogenated trimellitic anhydride.

The amine component may be, but is not limited to, a diamine such as an aliphatic diamine or an aromatic diamine, or a polyamine such as an aliphatic polyetheramine. These amine components may be used alone or in combination.

Examples of diamines include diamines with one benzene nucleus such as p-phenylenediamine (PPD), 1,3-diaminobenzene, 2,4-toluenediamine, 2,5-toluenediamine, and 2,6-toluenediamine; diaminodiphenyl ethers such as 4,4'-diaminodiphenyl ether, 3,3'-diaminodiphenyl ether, and 3,4'-diaminodiphenyl ether; 4,4'-diaminodiphenylmethane, 3,3'-dimethyl-4,4'-diaminobiphenyl, 2,2'-dimethyl-4,4'-diaminobiphenyl, 2,2'-bis(trifluoromethyl)-4,4'-diaminobiphenyl, 3,3'-dimethyl-4,4'-diaminodiphenylmethane, 3,3',5,5'-tetramethyl-4,4'-diaminodiphenylmethane, and bis(4-amino Phenyl) sulfide, 4,4'-diaminobenzanilide, 3,3'-dichlorobenzidine, 3,3'-dimethylbenzidine (o-tolidine), 2,2'-dimethylbenzidine (m-tolidine), 3,3'-dimethoxybenzidine, 2,2'-dimethoxybenzidine, 3,3'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl ether, 3,3'-diaminodiphenyl sulfide, 3,4'-diaminodiphenyl sulfide, 4,4'-diaminodiphenyl sulfide, 3,3'-diaminodiphenyl sulfone, 3,4'-diaminodiphenyl sulfone, 4,4'-diaminodiphenyl sulfone, 3,3'-diaminobenzophenone, 3,3'-diamino-4,4'-dichlorobenzophenone, 3,3'- Diamines with two benzene nuclei such as diamino-4,4'-dimethoxybenzophenone, 3,3'-diaminodiphenylmethane, 3,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylmethane, 2,2-bis(3-aminophenyl)propane, 2,2-bis(4-aminophenyl)propane, 2,2-bis(3-aminophenyl)-1,1,1,3,3,3-hexafluoropropane, 2,2-bis(4-aminophenyl)-1,1,1,3,3,3-hexafluoropropane, 3,3'-diaminodiphenyl sulfoxide, 3,4'-diaminodiphenyl sulfoxide, 4,4'-diaminodiphenyl sulfoxide, and 3,3'-dicarboxy-4,4'-diaminodiphenylmethane; 1,3-bis(3-aminophenyl)benzene; 1,3-bis(4- aminophenyl)benzene, 1,4-bis(3-aminophenyl)benzene, 1,4-bis(4-aminophenyl)benzene, 1,3-bis(4-aminophenoxy)benzene, 1,4-bis(3-aminophenoxy)benzene, 1,4-bis(4-aminophenoxy)benzene, 1,3-bis(3-aminophenoxy)-4-trifluoromethylbenzene, 3,3'-diamino-4-(4-phenyl)phenoxybenzophenone, 3,3'-diamino-4,4'-di(4-phenylphenoxy)benzophenone, 1,3-bis(3-aminophenylsulfide)benzene, 1,3-bis(4-aminophenylsulfide)benzene, 1,4-bis(4-aminophenylsulfide)benzene, 1,3-bis(3-aminophenylsulfone)benzene, 1,3-bis Diamines with three benzene nuclei such as (4-aminophenylsulfone)benzene, 1,4-bis(4-aminophenylsulfone)benzene, 1,3-bis[2-(4-aminophenyl)isopropyl]benzene, 1,4-bis[2-(3-aminophenyl)isopropyl]benzene, 1,4-bis[2-(4-aminophenyl)isopropyl]benzene, 3,3'-bis(3-aminophenoxy)biphenyl, 3,3'-bis(4-aminophenoxy)biphenyl, 4,4'-bis(3-aminophenoxy)biphenyl, 4,4'-bis(4-aminophenoxy)biphenyl, bis[3-(3-aminophenoxy)phenyl]ether, bis[3-(4-aminophenoxy)phenyl]ether, bis[4-(3-aminophenoxy)phenyl]ether, bis[4-( 4-aminophenoxy)phenyl]ether, bis[3-(3-aminophenoxy)phenyl]ketone, bis[3-(4-aminophenoxy)phenyl]ketone, bis[4-(3-aminophenoxy)phenyl]ketone, bis[4-(4-aminophenoxy)phenyl]ketone, bis[4-(4-aminophenoxy)phenyl]ketone, bis[3-(3-aminophenoxy)phenyl]sulfide, bis[3-(4-aminophenoxy)phenyl]sulfide, bis[4-(3-aminophenoxy)phenyl]sulfide, bis[4-(4-aminophenoxy)phenyl]sulfide, bis[3-(3-aminophenoxy)phenyl]sulfone, bis[3-(4-aminophenoxy)phenyl]sulfone, bis[4-(3-aminophenoxy)phenyl]sulfone , bis[3-(3-aminophenoxy)phenyl]methane, bis[3-(4-aminophenoxy)phenyl]methane, bis[4-(3-aminophenoxy)phenyl]methane, bis[4-(4-aminophenoxy)phenyl]methane, 2,2-bis[3-(3-aminophenoxy)phenyl]propane, 2,2-bis[3-(4-aminophenoxy)phenyl]propane, 2,2-bis[4-(3-aminophenoxy)phenyl]propane, 2,2-bis[4-(4-aminophenoxy)phenyl]propane, 2,2-bis[3-(3-aminophenoxy)phenyl]-1,1,1,3,3,3-hexafluoropropane, 2,2-bis[3-(4-aminophenoxy)phenyl]-1,1,1,3,3,3-hexafluoropropane, 2,2-bis[4-(3-aminophenoxy)phenyl] Examples of suitable diamines include aromatic diamines such as diamines with four benzene nuclei, such as 2,2-bis[4-(4-aminophenoxy)phenyl]-1,1,1,3,3,3-hexafluoropropane and 2,2-bis[4-(4-aminophenoxy)phenyl]-1,1,1,3,3,3-hexafluoropropane; and aliphatic diamines such as 1,2-diaminoethane, 1,3-diaminopropane, 1,4-diaminobutane, 1,5-diaminopentane, 1,6-diaminohexane, 1,7-diaminoheptane, 1,8-diaminooctane, 1,9-diaminononane, 1,10-diaminodecane, 1,11-diaminoundecane, 1,12-diaminododecane, and 1,2-diaminocyclohexane. Aliphatic polyetheramines include ethylene glycol and/or propylene glycol-based polyvalent amines. Furthermore, amines containing carboxyl groups can also be used, as described below.

Among the diamines listed above, those containing an ether bond (-O-) within the molecule, such as 2,2-bis[4-(4-aminophenoxy)phenyl]propane, 1,3-bis(4-aminophenoxy)benzene (TPE-R), and 4,4'-diaminodiphenyl ether, are preferred from the perspective of flexibility of the cured product.

Amines having a carboxyl group include diaminobenzoic acids such as 3,5-diaminobenzoic acid, 2,5-diaminobenzoic acid, and 3,4-diaminobenzoic acid, aminophenoxybenzoic acids such as 3,5-bis(3-aminophenoxy)benzoic acid and 3,5-bis(4-aminophenoxy)benzoic acid, 3,3'-diamino-4,4'-dicarboxybiphenyl, 4,4'-diamino-3,3'-dicarboxybiphenyl, 4,4'-diamino-2,2'-dicarboxybiphenyl, and 4,4'-diamino-2,2',5,5'-tetracarboxybiphenyl. carboxybiphenyl compounds such as carboxybiphenyl, carboxydiphenylmethane such as 3,3'-diamino-4,4'-dicarboxydiphenylmethane, 3,3'-dicarboxy-4,4'-diaminodiphenylmethane, 2,2-bis[3-amino-4-carboxyphenyl]propane, 2,2-bis[4-amino-3-carboxyphenyl]propane, 2,2-bis[3-amino-4-carboxyphenyl]hexafluoropropane, and 4,4'-diamino-2,2',5,5'-tetracarboxydiphenylmethane; carboxydiphenylalkanes such as 3,3'-diamino-4,4'-dicarboxydiphenyl ether, 4,4'-diamino-3,3'-dicarboxydiphenyl ether, 4,4'-diamino-2,2'-dicarboxydiphenyl ether, 4,4'-diamino-2,2',5,5'-tetracarboxydiphenyl ether, carboxydiphenyl ether compounds such as 3,3'-diamino-4,4'-dicarboxydiphenyl sulfone, 4,4'-diamino-3,3'-dicarboxydiphenyl sulfone, 4 Examples include diphenyl sulfone compounds such as 4,4'-diamino-2,2'-dicarboxydiphenyl sulfone and 4,4'-diamino-2,2',5,5'-tetracarboxydiphenyl sulfone, bis[(carboxyphenyl)phenyl]alkane compounds such as 2,2-bis[4-(4-amino-3-carboxyphenoxy)phenyl]propane, and bis[(carboxyphenoxy)phenyl]sulfone compounds such as 2,2-bis[4-(4-amino-3-carboxyphenoxy)phenyl]sulfone.

The isocyanate component may be, but is not limited to, aromatic diisocyanates and their isomers and polymers, aliphatic diisocyanates, alicyclic diisocyanates and their isomers, or other general-purpose diisocyanates. These isocyanate components may be used alone or in combination.

Examples of diisocyanates include aromatic diisocyanates such as 4,4'-diphenylmethane diisocyanate, tolylene diisocyanate, naphthalene diisocyanate, xylylene diisocyanate, biphenyl diisocyanate, diphenyl sulfone diisocyanate, and diphenyl ether diisocyanate, as well as their isomers and polymers; aliphatic diisocyanates such as hexamethylene diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate, and xylylene diisocyanate; alicyclic diisocyanates and isomers obtained by hydrogenating the above aromatic diisocyanates; and other general-purpose diisocyanates.

The polyamic acid represented by formula (1) may have an amide bond. This may be an amide bond obtained by reacting an isocyanate with a carboxylic acid, or may be formed by other reactions. It may also have bonds formed by other addition and condensation reactions.

To synthesize polyamic acid, known and commonly used alkali-soluble polymers, oligomers, and monomers having carboxyl groups and/or acid anhydride groups may be used. For example, these known and commonly used alkali-soluble resins may be reacted, alone or in combination with the above-mentioned carboxylic acid anhydride components, with the above-mentioned amines/isocyanates to produce resins.

The polyamic acid obtained as described above has at least one molecular chain end blocked with a compound having an unsaturated carbon bond. In the negative-tone photosensitive resin composition of the present invention, radical active species are generated from the oxime-based photopolymerization initiator upon light irradiation, and a crosslinking reaction proceeds through a thiol-ene reaction between the unsaturated carbon bond of the polyamic acid and the primary thiol group of the polyfunctional primary thiol compound crosslinking agent, rendering the composition insoluble in the developer. Furthermore, because the molecular chain ends of the polyamic acid are blocked, the molecular weight does not increase more than necessary during synthesis or storage, and the unexposed areas of the negative-tone photosensitive resin composition exhibit excellent developability and improved storage stability.

From the standpoint of resolution and storage stability, the unsaturated carbon bond at the molecular chain end of the polyamic acid is preferably derived from a compound having a norbornene structure. For example, when synthesizing the polyamic acid, an unsaturated carbon bond having a norbornene structure can be introduced at the molecular chain end of the polyamic acid by adding himic anhydride (5-norbornene-2,3-dicarboxylic anhydride) or methylnadic anhydride (methyl-5-norbornene-2,3-dicarboxylic anhydride) along with the carboxylic acid anhydride component, amine component, and/or isocyanate component.

The polyamic acid preferably has an acid value of 20 to 200 mgKOH/g, and more preferably 60 to 150 mgKOH/g. By keeping the acid value of the polyamic acid within this range, a good balance is achieved between the developability of the unexposed areas and the development resistance of the exposed areas, further improving resolution.

The negative-type photosensitive resin composition of the present invention uses a polyamic acid with a number-average molecular weight of less than 20,000 to promote reactivity with the polyfunctional primary thiol compound in exposed areas, thereby achieving excellent development resistance, while also achieving excellent developability in unexposed areas. Furthermore, taking into consideration resolution and cured coating film properties, it is preferable that the number-average molecular weight of the polyamic acid be greater than 4,000 and less than or equal to 10,000.

<(B) Photosensitizer>
The negative-type photosensitive resin composition of the present invention contains an oxime-based photopolymerization initiator as a photosensitizer. The oxime-based photopolymerization initiator is an oxime ester-based photopolymerization initiator, and is preferably an oxime ester-based photopolymerization initiator containing a structural moiety represented by the following general formula (I), and more preferably an oxime ester-based photopolymerization initiator having a carbazole structure. A dimeric oxime ester-based photopolymerization initiator may be used as the oxime ester-based photopolymerization initiator having a carbazole structure.

In formula (2), ^R1 represents a hydrogen atom, a phenyl group, an alkyl group, a cycloalkyl group, an alkanoyl group, or a benzoyl group, and ^R2 represents a phenyl group, an alkyl group, a cycloalkyl group, an alkanoyl group, or a benzoyl group.

The phenyl group represented by R ¹ and R ² may have a substituent, and examples of the substituent include an alkyl group having 1 to 6 carbon atoms, a phenyl group, and a halogen atom.

The alkyl group represented by ^R1 and ^R2 is preferably an alkyl group having 1 to 20 carbon atoms, which may contain one or more oxygen atoms in the alkyl chain, or may be substituted with one or more hydroxyl groups.

The cycloalkyl group represented by R ¹ and R ² is preferably a cycloalkyl group having 5 to 8 carbon atoms.

The alkanoyl group represented by R ¹ and R ² is preferably an alkanoyl group having 2 to 20 carbon atoms.

The benzoyl group represented by R ¹ and R ² may have a substituent, and examples of the substituent include an alkyl group having 1 to 6 carbon atoms, a phenyl group, and the like.

Examples of oxime ester photopolymerization initiators containing the structural moiety represented by general formula (2) include 1,2-octanedione-1-[4-(phenylthio)-2-(O-benzoyloxime)], compounds represented by the following formula (2-1), 2-(acetyloxyiminomethyl)thioxanthen-9-one, and oxime ester compounds with a carbazole skeleton, such as ethanone, 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]-, 1-(O-acetyloxime), and compounds represented by the following general formula (2-2).

In general formula (2-2), R ¹¹ has the same meaning as R ¹ in general formula (2), and R ¹² and R ¹⁴ each independently have the same meaning as R ² in general formula (2). R ¹³ represents a hydrogen atom, a halogen atom, an alkyl group having 1 to 12 carbon atoms, a cyclopentyl group, a cyclohexyl group, a phenyl group, a benzyl group, a benzoyl group, an alkanoyl group having 2 to 12 carbon atoms, an alkoxycarbonyl group having 2 to 12 carbon atoms (when the alkyl group constituting the alkoxyl group has 2 or more carbon atoms, the alkyl group may be substituted with one or more hydroxyl groups and may have one or more oxygen atoms in the middle of the alkyl chain), or a phenoxycarbonyl group.

Such oxime ester photopolymerization initiators are preferred because they have superior photosensitivity compared to other photopolymerization initiators (radical generators), and when the negative-type photosensitive resin composition of the present invention is exposed to light, they induce a thiol-ene reaction between the unsaturated carbon bond of the polyamic acid and the primary thiol group, resulting in excellent resolution. The oxime ester photopolymerization initiator may also be a dimer.

The dimeric oxime ester photopolymerization initiator is more preferably a compound represented by the following general formula (2-3).

In general formula (2-3), R ¹⁶ represents a hydrogen atom, an alkyl group, an alkoxy group, a phenyl group, or a naphthyl group. R ¹⁴ and R ¹⁵ each independently represent a hydrogen atom, an alkyl group, an alkoxy group, a halogen group, a phenyl group, a naphthyl group, an anthryl group, a pyridyl group, a benzofuryl group, or a benzothienyl group. Ar represents a single bond, or an alkylene group having 1 to 10 carbon atoms, a vinylene group, a phenylene group, a biphenylene group, a pyridylene group, a naphthylene group, an anthrylene group, a thienylene group, a furylene group, a 2,5-pyrrole-diyl group, a 4,4'-stilbene-diyl group, or a 4,2'-styrene-diyl group.
n represents an integer of 0 to 1.

In general formula (2-3), the alkyl group represented by R ¹⁶ is preferably an alkyl group having 1 to 17 carbon atoms. The alkoxy group represented by ^{R 16} is preferably an alkoxy group having 1 to 8 carbon atoms. The phenyl group represented by ^{R 16} may have a substituent, and examples of the substituent include an alkyl group (preferably having 1 to 17 carbon atoms), an alkoxy group (preferably having 1 to 8 carbon atoms), an amino group, an alkylamino group (preferably having 1 to 8 carbon atoms in the alkyl group), or a dialkylamino group (preferably having 1 to 8 carbon atoms in the alkyl group). The naphthyl group represented by R ¹⁶ may have a substituent, and examples of the substituent include the same groups as those described above for the substituent that the phenyl group represented by R ¹⁶ may have.

In general formula (2-3), the alkyl group represented by R ¹⁴ and R ¹⁵ is preferably an alkyl group having 1 to 17 carbon atoms. The alkoxy group represented by ^{R 14} and R ¹⁵ is preferably an alkoxy group having 1 to 8 carbon atoms. The phenyl group represented by ^{R 14} and R ¹⁵ may have a substituent, and examples of the substituent include an alkyl group (preferably having 1 to 17 carbon atoms), an alkoxy group (preferably having 1 to 8 carbon atoms), an amino group, an alkylamino group (preferably having 1 to 8 carbon atoms in the alkyl group), or a dialkylamino group (preferably having 1 to 8 carbon atoms in the alkyl group). The naphthyl group represented by R ¹⁴ and R ¹⁵ may have a substituent, and examples of the substituent include the same groups as the substituents that the phenyl group represented by R ¹⁴ and R ¹⁵ may have.

Furthermore, in the general formula (2-3), it is preferable that R ¹⁴ and R ¹⁶ are each independently a methyl group or an ethyl group, R22 is methyl or phenyl, Ar is a single bond, a phenylene group, a naphthylene group or a thienylene group, and n is 0.

As the compound represented by formula (I-3), the following compounds are more preferred.

Commercially available oxime ester photopolymerization initiators include CGI-325 manufactured by BASF Japan, Irgacure OXE01 (1,2-octanedione, 1-[4-(phenylthio)-, 2-(O-benzoyloxime)]), Irgacure OXE02 (ethanone, 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]-, 1-(O-acetyloxime)), N-1919 and NCI-831 manufactured by ADEKA Corporation, TR-PBG-304 manufactured by Changzhou Power Electronics New Materials Co., Ltd., and TOE-04-A3 manufactured by Nippon Chemical Industry Co., Ltd.

The amount of oxime ester photopolymerization initiator contained is not particularly limited, but may be 1 to 20 parts by mass per 100 parts by mass of alkali-soluble resin.

The negative-type photosensitive resin composition of the present invention may contain other photopolymerization initiators as the photosensitizer (B). Examples of other photopolymerization initiators include well-known and commonly used compounds such as benzophenones, acetophenones, aminoacetophenones, benzoin ethers, benzil ketals, acylphosphine oxides, oxime ethers, and titanocenes.

<(C) Crosslinking Agent>
The negative photosensitive resin composition of the present invention contains, as a crosslinking agent (C), a polyfunctional primary thiol compound having two or more functional thiol groups in one molecule, as represented by the following general formula (3):

X represents an aliphatic group having 1 to 40 carbon atoms, an aromatic hydrocarbon ring-containing group having 6 to 35 carbon atoms, or a heterocyclic ring-containing group having 2 to 35 carbon atoms, each having the same valence as m, and m represents an integer from 2 to 10. In the present invention, from the viewpoints of the resolution of the negative-type photosensitive resin composition and the flexibility of the cured product, m is preferably 2 to 6, and more preferably 4 to 6.

The above X is used as a linking group that bonds m -SH groups. The aliphatic group having 1 to 40 carbon atoms, aromatic hydrocarbon ring-containing group having 6 to 35 carbon atoms, and heterocyclic group having 2 to 35 carbon atoms, which have a valence equal to m and are represented by X above, are groups whose structure is obtained by removing m-1 hydrogen atoms from a monovalent aliphatic group having 1 to 40 carbon atoms, a monovalent aromatic hydrocarbon ring-containing group having 6 to 35 carbon atoms, and a monovalent heterocyclic group having 2 to 35 carbon atoms, respectively.

One or more methylene groups in the aliphatic group, aromatic hydrocarbon ring-containing group and heterocyclic ring-containing group for X in general formula (3) may be replaced with a group selected from —O—, —S—, —CO—, —O—CO—, —CO—O—, —O—CO—O—, —S—CO—, —CO—S—, —S—CO—O—, —O—CO—S—, —CO—NH—, —NH—CO—, —NH—CO—O—, —O—CO—NH—, —NR′—, —S—S— or —SO ₂ —, or may be replaced with a group formed by combining these groups, provided that the oxygen atoms are not adjacent to each other.

Divalent aliphatic groups having 1 to 40 carbon atoms represented by X in general formula (3) include groups having a structure in which one hydrogen atom has been removed from a monovalent aliphatic group having 1 to 40 carbon atoms. Examples include alkylenes such as methylene, ethylene, propylene, butylene, and butyldiyl; groups in which the methylene chain of the above alkylenes is replaced with -O-, -S-, -CO-O-, or -O-CO-; groups containing residues of polyols such as ethanediol, propanediol, butanediol, pentanediol, and hexanediol; residues of dithiols such as ethanedithiol, propanedithiol, butanedithiol, pentanedithiol, and hexanedithiol, and groups in which these groups are substituted with the substituents described below.

Examples of trivalent aliphatic groups having 1 to 40 carbon atoms represented by X include groups having a structure in which two hydrogen atoms have been removed from a monovalent aliphatic group having 1 to 40 carbon atoms, such as alkylidines such as propylidine and 1,1,3-butylidine; groups containing the residue of a polyol such as trimethylolpropane; and groups in which these groups are substituted with the substituents described below.

Examples of the tetravalent aliphatic group having 1 to 40 carbon atoms represented by X include groups having a structure in which three hydrogen atoms have been removed from the above-mentioned monovalent aliphatic group having 1 to 40 carbon atoms, such as groups containing a residue of a polyol such as pentaerythritol, and groups in which these groups are substituted with the substituents described below.

Examples of the hexavalent aliphatic group having 1 to 40 carbon atoms represented by X include groups having a structure in which five hydrogen atoms have been removed from a monovalent aliphatic group having 1 to 40 carbon atoms, such as groups containing a residue of a polyol such as dipentaerythritol, and groups in which such groups are substituted with the substituents described below.

The divalent aromatic hydrocarbon ring-containing group having 6 to 35 carbon atoms represented by X in general formula (3) includes groups having a structure in which one hydrogen atom has been removed from a monovalent aromatic hydrocarbon ring-containing group having 6 to 35 carbon atoms. Examples include arylene groups such as phenylene and naphthylene; residues of bifunctional phenols such as catechol and bisphenol; 2,4,8,10-tetraoxaspiro[5,5]undecane; and groups in which these groups are substituted with the substituents described below.

Examples of the trivalent aromatic hydrocarbon ring-containing group having 6 to 35 carbon atoms represented by X include groups having a structure in which two hydrogen atoms have been removed from a monovalent aromatic hydrocarbon ring-containing group having 6 to 35 carbon atoms, such as phenyl-1,3,5-trimethylene and groups in which these groups are substituted with the substituents described below.

Examples of the divalent heterocyclic ring-containing group having 2 to 35 carbon atoms represented by X include groups having a structure in which one hydrogen atom has been removed from a monovalent heterocyclic ring-containing group having 2 to 35 carbon atoms, such as groups having a pyridine ring, pyrimidine ring, piperidine ring, piperazine ring, triazine ring, furan ring, thiophene ring, indole ring, etc., and groups in which one or more hydrogen atoms of these groups have been substituted with the substituents described below.

Examples of the trivalent heterocyclic ring-containing group having 2 to 35 carbon atoms represented by X include groups having a structure in which two hydrogen atoms have been removed from a monovalent heterocyclic ring-containing group having 2 to 35 carbon atoms, such as groups having an isocyanuric ring, groups having a triazine ring, and groups in which one or more hydrogen atoms of these groups have been substituted with a substituent described below.

Examples of the tetravalent heterocyclic ring-containing group having 2 to 35 carbon atoms represented by X include groups having a structure in which three hydrogen atoms have been removed from a monovalent heterocyclic ring-containing group having 2 to 35 carbon atoms, such as groups containing a glycoluril group and groups in which the hydrogen atoms of this group have been substituted with the substituents described below.

The functional groups in X, such as aliphatic groups, aromatic hydrocarbon ring-containing groups, and heterocyclic ring-containing groups, may have a substituent, and unless otherwise specified, are either unsubstituted functional groups that do not have a substituent or functional groups that have a substituent.

The crosslinking agent (C) is preferably contained in an amount of 0.5 to 50 parts by mass, and more preferably 10 to 30 parts by mass, per 100 parts by mass of the alkali-soluble resin (A).

(C) In addition to the primary thiol compounds described above, secondary thiol compounds may also be used as crosslinking agents, provided that the effects of the present invention are not impaired.

<Other ingredients>
The negative-tone photosensitive resin composition of the present invention may contain compounds having (meth)acrylic groups, epoxy groups, oxetanyl groups, or the like that are reactive with the unsaturated carbon bonds or carboxyl groups of the polyamic acid to improve the development resistance of the exposed area and the physical properties of the cured film; known plasticizers or thermal acid generators to promote the imidization reaction of the polyamic acid; known sensitizers to improve photosensitivity; and known adhesion agents such as silane coupling agents to improve adhesion to the substrate. Furthermore, various organic or inorganic low-molecular-weight or high-molecular-weight compounds may be added to impart processing properties and various functionalities to the negative-tone photosensitive resin composition. For example, surfactants, leveling agents, fine particles, etc. may be used. Examples of fine particles include organic fine particles such as polystyrene and polytetrafluoroethylene, and inorganic fine particles such as silica, carbon, and layered silicates. The negative-tone photosensitive resin composition of the present invention may also contain various colorants, fibers, etc.

The negative-tone photosensitive resin composition of the present invention may contain a solvent for viscosity adjustment, etc. The solvent is not particularly limited as long as it dissolves (A) the alkali-soluble resin, (B) the photosensitizer, (C) the crosslinker, and other components. Examples include N,N'-dimethylformamide, N-methylpyrrolidone, N-ethyl-2-pyrrolidone, N,N'-dimethylacetamide, diethylene glycol dimethyl ether, cyclopentanone, γ-butyrolactone, α-acetyl-γ-butyrolactone, tetramethylurea, 1,3-dimethyl-2-imidazolinone, N-cyclohexyl-2-pyrrolidone, dimethyl sulfoxide, hexamethylphosphoramide, pyridine, γ-butyrolactone, and diethylene glycol monomethyl ether. These solvents may be used alone or in combination. The amount of solvent used can be determined appropriately depending on the coating film thickness and viscosity. For example, it can be used in the range of 50 to 9,000 parts by mass per 100 parts by mass of (A) alkali-soluble resin.

[Dry film]
The dry film of the present invention has a resin layer obtained by applying the above-mentioned negative photosensitive resin composition to at least one surface of a substrate film and then drying the applied resin layer, and is used by laminating the resin layer in contact with the substrate.

A dry film can be produced by uniformly applying the photosensitive resin composition of the present invention to a film using an appropriate method such as a blade coater, lip coater, comma coater, or film coater, drying the applied film to form the resin layer described above, and preferably laminating a protective film (so-called cover film) on top of the applied film. The protective film and the substrate film may be made of the same film material, or different films may be used.

In dry films, any of the film materials known for use in dry films can be used for the base film and protective film. The base film can be a thermoplastic film, such as a polyester film such as polyethylene terephthalate, with a thickness of 2 to 150 μm. The protective film can be a polyethylene film, polypropylene film, or the like, but it is preferable for the adhesive strength with the resin layer to be weaker than that of the base film.

The thickness of the resin layer on the dry film is preferably 100 μm or less, and more preferably in the range of 5 to 50 μm.

[Cured product]
The cured product of the present invention is obtained by curing the above-mentioned negative photosensitive resin composition in a predetermined step. The patterned film, which is the cured product, may be produced by a known, commonly used method, for example, as follows.

First, in step 1, a coating film is obtained by applying a negative-tone photosensitive resin composition to a substrate and drying it, or by transferring a resin layer from a dry film onto the substrate. Methods for applying the negative-tone photosensitive resin composition to a substrate include conventional methods for applying photosensitive resin compositions, such as using a spin coater, bar coater, blade coater, curtain coater, or screen printer; spray coating using a spray coater; and inkjet printing. Methods for drying the coating include air drying, heat drying in an oven or on a hot plate, and vacuum drying. Furthermore, it is desirable to dry the coating under conditions that do not cause cyclization of the polyamic acid in the negative-tone photosensitive resin composition or reaction between the polyamic acid and the crosslinker. Specifically, natural drying, air drying, or heat drying can be performed at 70 to 110°C for 1 to 30 minutes. Preferably, drying is performed on a hot plate for 1 to 10 minutes. Vacuum drying is also possible, in which case it can be carried out at room temperature for 20 minutes to 1 hour. There are no particular restrictions on the substrate on which the negative-type photosensitive resin composition coating is formed, and it can be widely applied to semiconductor substrates such as silicon wafers, wiring boards, various resins, metals, etc.

Next, in step 2, the coating film is exposed to light either directly or through a patterned photomask. The exposure light has a wavelength that can generate radical active species as the photosensitizer (B). Specifically, the exposure light preferably has a maximum wavelength in the range of 350 to 440 nm. As mentioned above, the photosensitivity can be adjusted by appropriately blending a sensitizer. Examples of exposure devices that can be used include contact aligners, mirror projection devices, steppers, and laser direct exposure devices.

Next, in step 3, the coating film is treated with a developer. This removes the exposed portions of the coating film, forming a patterned film of the negative-type photosensitive resin composition of the present invention.

The development method can be any of the conventional photoresist development methods, such as the rotary spray method, paddle method, and immersion method with ultrasonic treatment. Examples of developing solutions include aqueous solutions of inorganic alkalis such as sodium hydroxide, sodium carbonate, sodium silicate, and aqueous ammonia; organic amines such as ethylamine, diethylamine, triethylamine, and triethanolamine; and quaternary ammonium salts such as tetramethylammonium hydroxide and tetrabutylammonium hydroxide. If necessary, these solutions may also contain an appropriate amount of a water-soluble organic solvent or surfactant, such as methanol, ethanol, or isopropyl alcohol. The coating film is then washed with a rinse solution, if necessary, to obtain a patterned film. Distilled water, methanol, ethanol, isopropyl alcohol, or the like can be used alone or in combination as the rinse solution. The above solvents may also be used as the developing solution.

Then, in step 4, the patterned film is heated to obtain a cured coating film (cured product). This heating cyclizes the polyamic acid, yielding a polyimide. The heating temperature is set appropriately so that the patterned film of the negative photosensitive resin composition can be cured. For example, heating is performed in an inert gas atmosphere at a temperature of 150°C or higher but lower than 350°C for approximately 5 to 120 minutes. A more preferred heating temperature range is 180 to 250°C. Heating can be performed using, for example, a hot plate, an oven, or a temperature-programmable heating oven. The atmosphere (gas) used in this process may be air, or an inert gas such as nitrogen or argon.

The negative-type photosensitive resin composition of the present invention is not particularly limited in its applications, and is suitable for use, for example, as a paint, printing ink, adhesive, or material for forming display devices, semiconductor devices, electronic components, optical components, or building materials. Specifically, as a material for forming display devices, it can be used as a layer-forming material or image-forming material for color filters, flexible display films, resist materials, alignment films, etc. as a material for forming semiconductor devices. It can also be used as a layer-forming material for resist materials and buffer coat films, etc. as a material for forming electronic components. It can also be used as a sealing material or layer-forming material for printed wiring boards, interlayer insulating films, wiring coating films, etc. as a material for forming optical components. It can also be used as an optical material or layer-forming material for holograms, optical waveguides, optical circuits, optical circuit components, anti-reflection films, etc. as a material for forming optical components. It can also be used as a building material for paints, coatings, etc.

It is primarily used as a pattern-forming material, and the patterned films formed thereby function as components that impart heat resistance and insulating properties as permanent films made of, for example, polyimide. Therefore, it is particularly suitable for use as surface protective films for semiconductor devices, display devices, and light-emitting devices, interlayer insulating films, rewiring insulating films, protective films for flip-chip devices, protective films for devices with bump structures, interlayer insulating films for multilayer circuits, insulating materials for passive components, protective films for printed wiring boards such as solder resists and coverlay films, and liquid crystal alignment films. In particular, the photosensitive resin composition of the present invention exhibits excellent chemical resistance in the cured product, making it suitable as a material for forming laminated layers, such as interlayer insulating films and rewiring insulating films.

The present invention will be explained in more detail below using examples, but the present invention is not limited to these examples. Note that all "parts" and "%" below are by weight unless otherwise specified.

(A) Preparation of Alkali-Soluble Resins The following six types of resins were prepared.
(1) Alkali-soluble resin 1
5.54 g of 2,2-bis[4-(4-aminophenoxy)phenyl]propane (BAPP) and 3.30 g of 4,4'-diaminodiphenyl ether (ODA) were weighed into a screw tube and dissolved in 71 mL of N-methylpyrrolidone in a dry atmosphere (20°C, 20% RH). After dissolution by stirring, 7.31 g of 4,4'-oxydiphthalic anhydride (ODPA) was gradually added in a dry atmosphere and allowed to react overnight (16 hours) at room temperature. Subsequently, 5-norbornene-2,3-dicarboxylic anhydride (NA) was added and the reaction was allowed to proceed at room temperature for 8 hours to obtain alkali-soluble resin 1. The molecular weight of the resulting alkali-soluble resin 1, measured by GPC in terms of polystyrene, was found to be a number average molecular weight (Mn) of 4,300 and a weight average molecular weight (Mw) of 10,500.

(2) Alkali-soluble resin 2
5.54 g of 2,2-bis[4-(4-aminophenoxy)phenyl]propane (BAPP) and 3.30 g of 4,4'-diaminodiphenyl ether (ODA) were weighed into a screw tube and dissolved in 71 mL of N-methylpyrrolidone in a dry atmosphere (20°C, 20% RH). After dissolution by stirring, 7.91 g of 4,4'-oxydiphthalic anhydride (ODPA) was gradually added in a dry atmosphere and allowed to react overnight (16 hours) at room temperature. Subsequently, 5-norbornene-2,3-dicarboxylic anhydride (NA) was added and the reaction was allowed to proceed at room temperature for 8 hours to obtain alkali-soluble resin 2. The molecular weight of the resulting alkali-soluble resin 2, measured by GPC in terms of polystyrene, was found to be a number average molecular weight (Mn) of 6,000 and a weight average molecular weight (Mw) of 16,000.

(3) Alkali-soluble resin 3
5.54 g of 2,2-bis[4-(4-aminophenoxy)phenyl]propane (BAPP) and 3.30 g of 4,4'-diaminodiphenyl ether (ODA) were weighed into a screw tube and dissolved in 73 mL of N-methylpyrrolidone in a dry atmosphere (20°C, 20% RH). After dissolution by stirring, 8.38 g of 4,4'-oxydiphthalic anhydride (ODPA) was gradually added in a dry atmosphere and allowed to react overnight (16 hours) at room temperature. Subsequently, 5-norbornene-2,3-dicarboxylic anhydride (NA) was added and the mixture was allowed to react at room temperature for 8 hours to obtain alkali-soluble resin 3. The molecular weight of the resulting alkali-soluble resin 3, measured by GPC in terms of polystyrene, was found to be a number average molecular weight (Mn) of 8,000 and a weight average molecular weight (Mw) of 23,000.

(4) Alkali-soluble resin 4
5.54 g of 2,2-bis[4-(4-aminophenoxy)phenyl]propane (BAPP) and 3.30 g of 4,4'-diaminodiphenyl ether (ODA) were weighed into a screw tube and dissolved in 73 mL of N-methylpyrrolidone in a dry atmosphere (20°C, 20% RH). After dissolution by stirring, 5.52 g of 4,4'-oxydiphthalic anhydride (ODPA) was gradually added in a dry atmosphere and allowed to react overnight (16 hours) at room temperature. Subsequently, 5-norbornene-2,3-dicarboxylic anhydride (NA) was added and the mixture was allowed to react at room temperature for 8 hours to obtain alkali-soluble resin 4. The molecular weight of the resulting alkali-soluble resin 4, measured by GPC in terms of polystyrene, was found to be a number average molecular weight (Mn) of 2,500 and a weight average molecular weight (Mw) of 8,000.

(5) Alkali-soluble resin 5
5.85 g of 1,3-bis(4-aminophenoxy)benzene (TPE-R) was weighed into a screw tube and dissolved in 48 mL of N-methylpyrrolidone in a dry atmosphere (20°C, 20% RH). After dissolution by stirring, 4.72 g of 4,4'-oxydiphthalic anhydride (ODPA) was gradually added in a dry atmosphere and allowed to react overnight (16 hours) at room temperature. Subsequently, 5-norbornene-2,3-dicarboxylic anhydride (NA) was added and allowed to react at room temperature for 8 hours to obtain alkali-soluble resin 5. The molecular weight of the resulting alkali-soluble resin 5, measured by GPC in terms of polystyrene, was found to be a number average molecular weight (Mn) of 4,000 and a weight average molecular weight (Mw) of 10,000.

(6) Alkali-soluble resin 6
5.54 g of 2,2-bis[4-(4-aminophenoxy)phenyl]propane (BAPP) and 3.30 g of 4,4'-diaminodiphenyl ether (ODA) were weighed into a screw tube and dissolved in 73 mL of N-methylpyrrolidone in a dry atmosphere (20°C, 20% RH). After dissolution by stirring, 8.70 g of 4,4'-oxydiphthalic anhydride (ODPA) was gradually added in a dry atmosphere and allowed to react overnight (16 hours) at room temperature. Subsequently, 5-norbornene-2,3-dicarboxylic anhydride (NA) was added and the mixture was allowed to react at room temperature for 8 hours to obtain alkali-soluble resin 6. The molecular weight of the resulting alkali-soluble resin 6, measured by GPC in terms of polystyrene, was found to be a number average molecular weight (Mn) of 20,000 and a weight average molecular weight (Mw) of 41,000.

(B) Preparation of Photosensitizer The following three types of photopolymerization initiators were prepared as photosensitizers.
Photosensitizer 1: Oxime ester photopolymerization initiator (IRGACURE OXE01, manufactured by BASF Japan)
Photosensitizer 2: Acylphosphine oxide photopolymerization initiator (Omnirad 819, manufactured by IGM Resins)
Photosensitizer 3: Acetophenone photopolymerization initiator (manufactured by IGM Resins, Omunirad 369)

(C) Preparation of Crosslinking Agents The following three types of thiol compounds were prepared as crosslinking agents.
Crosslinker 1: tetrafunctional primary thiol compound (TS-G, manufactured by Shikoku Chemicals Co., Ltd.)

Crosslinker 2: Hexafunctional primary thiol compound (DPMP, manufactured by SC Organic Chemical Co., Ltd.)

Crosslinker 3: Trifunctional primary thiol compound (TEMPIC, manufactured by SC Organic Chemical Co., Ltd.)

[Examples 1 to 8 and Comparative Examples 1 to 4]
Each component was mixed with 100 parts by mass of each alkali-soluble resin synthesized above in the proportions shown in Table 1, and completely dissolved to obtain a varnish of a negative photosensitive resin composition. All of the blending amounts in Table 1 are blending amounts calculated as non-volatile components.

[Elongation of cured product]
The varnish was applied to a copper-sputtered silicon substrate using a spin coater to a dried film thickness of 45 μm, and then dried on a hot plate at 100°C for 2 minutes. The dried varnish film was then exposed to i-line light at an exposure dose of 2000 mJ/ ^cm2 . The film was then heated in an inert gas oven (CLH-21CD-S, manufactured by Koyo Thermo Systems Co., Ltd.) under a nitrogen atmosphere at 110°C for 10 minutes, held at 150°C for 30 minutes, and then further heated and heated at the curing temperature shown in Table 1 for 60 minutes to obtain a cured film.
The cured film thus obtained was peeled off, and then the breaking elongation was measured by a tensile test using EZ-SX manufactured by Shimadzu Corporation. The evaluation criteria were as follows:
⊚: The elongation at break was 15% or more.
Good: The breaking elongation was less than 15% and 10% or more.
△: The elongation at break was less than 10% and 5% or more.
×: The breaking elongation was less than 5, or a free-standing film could not be obtained.
The results of the elongation evaluation are shown in Table 1 below.

[Resolution]
The varnish was applied to a copper-sputtered silicon substrate using a spin coater to a dried film thickness of 12 μm, and then dried on a hot plate at 100°C for 2 minutes. The dried varnish film was then irradiated (exposed) with i-line light at an exposure dose of 1000 mJ/ ^cm2 , developed in a 1% aqueous sodium carbonate solution for 80 seconds, and rinsed with water to obtain a positive pattern. The contrast was calculated using the following formula:
Contrast = development speed of unexposed area (film thickness/development time)/development speed of exposed area (film thickness/development time)
Film thickness (μm): value obtained by subtracting the film thickness after development from the film thickness before development. Development time (min): time spent immersed in the developer. Evaluation was made according to the contrast value as follows.
⊚: 15 or more, ◯: less than 15, 5 or more, x: less than 5 The results of the evaluation of resolution are shown in Table 1 below.

Claims (8)

(A) an alkali-soluble resin;
(B) a photosensitizer;
(C) a crosslinking agent;
A negative-type photosensitive resin composition (excluding a negative-type photosensitive resin composition containing a colorant) ,
The alkali-soluble resin (A) is represented by the following formula (1):
(In general formula (1), X represents a tetravalent organic group, Y represents a divalent organic group, and n represents an integer.)
and a polyamic acid having a number average molecular weight of less than 20,000, which has a repeating unit represented by the formula:
the (B) photosensitizer contains an oxime-based photopolymerization initiator,
the (C) crosslinking agent contains a polyfunctional primary thiol compound having two or more functional thiol groups in one molecule;
A negative photosensitive resin composition comprising: The negative-type photosensitive resin composition according to claim 1, wherein the polyamic acid is derived from a compound in which the unsaturated carbon bond at the end of the molecular chain has a norbornene structure. The negative-type photosensitive resin composition according to claim 1 or 2, wherein the polyfunctional primary thiol compound has 2 to 6 thiol groups per molecule. The negative-type photosensitive resin composition according to any one of claims 1 to 3, wherein at least one organic group of X and Y in formula (1) has an ether bond (-O-). The negative-type photosensitive resin composition according to any one of claims 1 to 4, wherein the number-average molecular weight of the polyamic acid is greater than 4,000 and less than or equal to 10,000. A dry film comprising a base film and a resin layer provided on at least one side of the base film,
A dry film, wherein the resin layer is a product obtained by applying and drying the negative photosensitive resin composition according to any one of claims 1 to 5. A negative-type photosensitive resin composition according to any one of claims 1 to 5, or a cured resin layer of a dry film according to claim 6. An electronic component comprising the cured product described in claim 7.