JP2024050294A - Photosensitive resin composition - Google Patents

Abstract

The present invention provides a photosensitive resin composition having excellent resolution and film retention. The photosensitive resin composition includes (A) a polyimide precursor, (B) a crosslinking agent, (C) a photoradical generator, and (D) a photosensitizer having a molecular weight of 400 or more. [Selected Figures] None

Description

The present invention relates to a photosensitive resin composition, and a photosensitive film, a semiconductor package substrate, and a semiconductor device that use the photosensitive resin composition.

Conventionally, polyimide resins, which have excellent heat resistance and insulating properties, have been used in insulating layers of semiconductor devices. In general, polyimide resins have low solubility in solvents. Therefore, after forming a layer of a photosensitive resin composition containing a polyimide precursor, the polyimide precursor is sometimes cyclized to form an insulating layer.

The technologies described in Patent Documents 1 and 2 were previously known.

Patent No. 5632978 Japanese Patent No. 6440944

In recent years, with the increase in communication speed and capacity in communication devices, the semiconductor package substrate of the communication device is required to have high density wiring. From the viewpoint of responding to the high density wiring, it is desirable that the photosensitive resin composition used in the semiconductor package substrate has excellent resolution. In addition, since photosensitive resin compositions containing polyimide precursors generally have poor developability, long development times are required when developing fine patterns. However, if the development time is long, a part of the photosensitive resin composition dissolves in the developer in the exposed area, and the resulting insulating layer may become thin. Therefore, there has been a demand for the development of a technology to improve both the resolution and film retention of photosensitive resin compositions containing polyimide precursors.

The present invention was devised in view of the above problems, and aims to provide a photosensitive resin composition having excellent resolution and film retention; a photosensitive film containing the photosensitive resin composition; a semiconductor package substrate having an insulating layer formed of a cured product of the photosensitive resin composition and a method for manufacturing the same; and a semiconductor device having the semiconductor package substrate.

The present inventors have conducted extensive research to solve the above-mentioned problems, and as a result, have found that a photosensitive resin composition containing (A) a polyimide precursor, (B) a crosslinking agent, (C) a photoradical generator, and (D) a photosensitizer having a molecular weight of 400 or more can solve the above-mentioned problems, thereby completing the present invention.
That is, the present invention includes the following.

（式（Ａ－１）において、
Ａ^ａは、それぞれ独立に、４価の有機基を表し、
Ｂ^ａは、それぞれ独立に、２価の有機基を表し、
Ｒ^１ａ及びＲ^２ａは、それぞれ独立に、水素原子又は１価の有機基を表し、
ｎ_ａは、５以上２００以下の整数を表す。）
［５］ （Ａ）成分が、５０００以上１００００００以下の重量平均分子量を有する、［１］～［４］のいずれか一項に記載の感光性樹脂組成物。
［６］ （Ｂ）成分が、エチレン性不飽和結合を含有する、［１］～［５］のいずれか一項に記載の感光性樹脂組成物。
［７］ （Ｃ）成分が、（Ｃ－１）４５０以上の分子量を有する光ラジカル発生剤を含む、［１］～［６］のいずれか一項に記載の感光性樹脂組成物。
［８］ （Ｄ）成分が、分子内に第３級アミノ基を含有する、［１］～［７］のいずれか一項に記載の感光性樹脂組成物。
［９］ （Ｄ）成分が、分子内にアミノベンゾイル基を含有する、［１］～［８］のいずれか一項に記載の感光性樹脂組成物。
［１０］ 支持体と、前記支持体上に形成された感光性樹脂組成物層と、を備え、
感光性樹脂組成物層が、［１］～［９］のいずれか一項に記載の感光性樹脂組成物を含む、感光性フィルム。
［１１］ ［１］～［９］のいずれか１項に記載の感光性樹脂組成物の硬化物により形成された絶縁層を備える、半導体パッケージ基板。
［１２］ ［１１］に記載の半導体パッケージ基板を備える、半導体装置。
［１３］ 回路基板上に、［１］～［９］のいずれか１項に記載の感光性樹脂組成物を含む感光性樹脂組成物層を形成する工程と、
感光性樹脂組成物層に活性光線を照射する工程と、
感光性樹脂組成物層を現像する工程と、
を含む、半導体パッケージ基板の製造方法。 [1] (A) a polyimide precursor,
(B) a crosslinking agent,
A photosensitive resin composition comprising: (C) a photoradical generator; and (D) a photosensitizer having a molecular weight of 400 or more.
[2] The photosensitive resin composition according to [1], wherein the component (A) contains an indane skeleton.
[3] The photosensitive resin composition according to [1] or [2], in which the component (A) contains a radical reactive group.
[4] The photosensitive resin composition according to any one of [1] to [3], wherein the component (A) contains a structural unit represented by the following formula (A-1):

(In formula (A-1),
Each A ^a independently represents a tetravalent organic group.
Each B ^a independently represents a divalent organic group.
R ^1a and R ^2a each independently represent a hydrogen atom or a monovalent organic group;
n _a represents an integer of 5 or more and 200 or less.
[5] The photosensitive resin composition according to any one of [1] to [4], wherein the component (A) has a weight average molecular weight of 5,000 or more and 1,000,000 or less.
[6] The photosensitive resin composition according to any one of [1] to [5], wherein the component (B) contains an ethylenically unsaturated bond.
[7] The photosensitive resin composition according to any one of [1] to [6], wherein the component (C) contains (C-1) a photoradical generator having a molecular weight of 450 or more.
[8] The photosensitive resin composition according to any one of [1] to [7], wherein the component (D) contains a tertiary amino group in the molecule.
[9] The photosensitive resin composition according to any one of [1] to [8], wherein the component (D) contains an aminobenzoyl group in the molecule.
[10] A photosensitive resin composition layer comprising a support and a photosensitive resin composition layer formed on the support,
A photosensitive film, wherein the photosensitive resin composition layer contains the photosensitive resin composition according to any one of [1] to [9].
[11] A semiconductor package substrate comprising an insulating layer formed from a cured product of the photosensitive resin composition according to any one of [1] to [9].
[12] A semiconductor device comprising the semiconductor package substrate according to [11].
[13] A step of forming a photosensitive resin composition layer containing the photosensitive resin composition according to any one of [1] to [9] on a circuit board;
A step of irradiating the photosensitive resin composition layer with actinic rays;
developing the photosensitive resin composition layer;
A method for manufacturing a semiconductor package substrate, comprising:

The present invention provides a photosensitive resin composition having excellent resolution and film retention; a photosensitive film containing the photosensitive resin composition; a semiconductor package substrate having an insulating layer formed of a cured product of the photosensitive resin composition and a method for producing the same; and a semiconductor device having the semiconductor package substrate.

The present invention will be described in detail below with reference to embodiments and examples. However, the present invention is not limited to the embodiments and examples given below, and may be modified as desired without departing from the scope of the claims and their equivalents.

In the following description, unless otherwise specified, the term "optionally substituted" in reference to a compound or group means that the hydrogen atoms of the compound or group are not substituted with substituents, and that some or all of the hydrogen atoms of the compound or group are substituted with substituents.

In the following description, unless otherwise specified, the term "organic group" refers to a group that contains at least carbon atoms as skeletal atoms, and may be linear, branched, or cyclic.

In the following description, the amount of each component in the photosensitive resin composition represents the value when the non-volatile components in the photosensitive resin composition are taken as 100% by mass, unless otherwise specified.

[Outline of photosensitive resin composition]
The photosensitive resin composition according to one embodiment of the present invention contains (A) a polyimide precursor, (B) a crosslinking agent, (C) a photoradical generator, and (D) a photosensitizer having a molecular weight of 400 or more. Hereinafter, the "photosensitizer having a molecular weight of 400 or more (D)" may be referred to as "high molecular weight sensitizer (D)". This photosensitive resin composition can usually be used as a negative type photosensitive resin composition.

The photosensitive resin composition according to this embodiment can have excellent resolution and film retention. In addition, the photosensitive resin composition according to this embodiment can usually reduce undercuts.

Unless otherwise specified, "resolution" refers to the property of being able to form small holes in a photosensitive resin composition by exposure and development. In general, the smaller the diameter of the holes that can be formed, the better the resolution.

Unless otherwise specified, "film retention" refers to the property of being able to increase the ratio of the thickness of the photosensitive resin composition layer after exposure and development based on the thickness of the photosensitive resin composition layer before exposure and development, and thus to the property of being able to increase the ratio of the thickness of the photosensitive resin composition layer cured after said exposure and development. The above ratio is sometimes called the "film retention ratio," and generally, the higher the film retention ratio, the better the film retention.

In general, when a photosensitive resin composition layer is exposed to light and developed to form a hole, the diameter of the hole may become larger the deeper the hole (i.e., the farther from the exposed surface). Therefore, in a cross section of the photosensitive resin composition layer cut along a plane in the thickness direction, the cross-sectional shape of the hole may be an inverted taper shape in which the diameter of the bottom formed at the deepest part is larger than the diameter of the opening formed on the exposed surface. In this case, the difference between the radius of the opening corresponding to the top of the hole and the radius of the bottom corresponding to the deepest part of the hole (bottom radius - top radius) is called "undercut". The closer to zero the undercut, the better. Hereinafter, the property of reducing undercut may be called "undercut resistance".

The present inventors speculate that the mechanism by which the photosensitive resin composition according to the present embodiment provides the above-mentioned excellent effects is as follows, although the technical scope of the present invention is not limited to the mechanism described below.
Since the molecular weight of the (D) high molecular weight sensitizer is as large as 400 or more, the energy obtained by absorbing light during exposure is large. Therefore, when the (C) photoradical generator receives this energy, photopolymerization can proceed quickly. Therefore, photopolymerization can proceed before being inhibited by oxygen. Therefore, the photocuring of the photosensitive resin composition can proceed quickly and effectively. In addition, the solubility of the photosensitive resin composition in the developer can be quickly and effectively reduced. Therefore, as described above, it is possible to have excellent resolution and residual film properties, and further, undercuts can usually be reduced. Furthermore, the molecular size of the (D) high molecular weight sensitizer having a large molecular weight is generally large. Thus, the solubility of molecules with a large size in the developer tends to be lower than that of molecules with a small size. Therefore, the frequency of molecules detaching from the wall surface of the hole due to dissolution during development can be suppressed, and the undercut can also be reduced by this action.

[(A) Polyimide precursor]
The photosensitive resin composition according to the present embodiment includes a polyimide precursor (A) as the component (A). The polyimide precursor (A) can form a polyimide by ring closure upon heating. Therefore, according to the cured product obtained by thermally curing the photosensitive resin composition including the polyimide precursor (A), a good insulating layer can be formed by utilizing the excellent physical properties of the polyimide. In addition, by using the polyimide precursor (A), the resolution of the photosensitive resin composition can be improved. The polyimide precursor (A) may be used alone or in combination of two or more kinds.

(A) As the polyimide precursor, a resin containing a plurality of one or more structural units selected from the group consisting of amic acid structural units and amic acid ester structural units can be used. The amic acid structural unit generally refers to a structural unit having a structure obtained by reacting a tetracarboxylic dianhydride with a diamine compound. The amic acid ester structural unit generally refers to a structural unit having a structure obtained by esterifying a part or all of the carboxy groups of an amic acid obtained by reacting a tetracarboxylic dianhydride with a diamine compound.

It is preferable that the (A) polyimide precursor contains an indane skeleton in the molecule of the (A) polyimide precursor. The indane skeleton represents the skeleton shown in the following (a1-1). When the (A) polyimide precursor containing an indane skeleton is used, the solubility of the non-exposed portion of the photosensitive resin composition in the developer can be increased. Therefore, the resolution, film remaining property, and undercut resistance can be particularly improved. In particular, it is preferable that the (A) polyimide precursor contains a trimethylindane skeleton shown in the following formula (a1-2). When the (A) polyimide precursor contains an amic acid structural unit or an amic acid ester structural unit, the indane skeleton is preferably included in the structural portion derived from the diamine compound.

It is preferable that the polyimide precursor (A) contains a radical reactive group in the molecule of the polyimide precursor (A). The radical reactive group represents a reactive group that can undergo polymerization by radicals generated by heat or light, and examples thereof include groups containing non-aromatic carbon-carbon unsaturated bonds. When the polyimide precursor (A) containing a radical reactive group is used, the polyimide precursor (A) is polymerized by exposure to light, and the solubility of the photosensitive resin composition in the developer can be effectively reduced. Therefore, the resolution, film remaining property, and undercut resistance can be particularly improved. For example, the radical reactive group may be contained in the esterified portion of the amic acid ester structural unit.

Examples of the tetracarboxylic dianhydride include aliphatic tetracarboxylic dianhydrides and aromatic tetracarboxylic dianhydrides, with aliphatic tetracarboxylic dianhydrides being preferred. Examples of the tetracarboxylic dianhydride include 4,4'-oxydiphthalic dianhydride, 3,3',4,4'-benzophenone tetracarboxylic dianhydride, pyromellitic dianhydride, 3,4,9,10-perylene tetracarboxylic dianhydride, 3,3',4,4'-diphenylsulfone tetracarboxylic dianhydride, 3,3',4,4'-biphenyl tetracarboxylic dianhydride, 1,2,5,6-naphthalene tetracarboxylic dianhydride, 3,3',4,4'-para-terphenyl tetracarboxylic dianhydride, 3,3',4,4'-meta-terphenyl tetracarboxylic dianhydride, 1,2, Examples of the tetracarboxylic dianhydride include 4,5-cyclohexanetetracarboxylic dianhydride, bicyclo[2.2.2]oct-7-ene-2,3,5,6-tetracarboxylic dianhydride, bicyclo[2.2.1]heptane-2-endo-3-endo-5-exo-6-exo-2,3,5,6-tetracarboxylic dianhydride, bicyclo[2.2.1]heptane-2-exo-3-exo-5-exo-6-exo-2,3,5,6-tetracarboxylic dianhydride, bicyclo[2.2.1]heptane-2,3,5,6-tetracarboxylic dianhydride, and decahydro-dimethanonaphthalenetetracarboxylic dianhydride. The tetracarboxylic dianhydride may be used alone or in combination of two or more.

Examples of the diamine compound include bis[2-(3-aminopropoxy)ethyl]ether, 1,4-butanediol-bis(3-aminopropyl)ether, 3,9-bis(3-aminopropyl)-2,4,8,10-tetraspiro-5,5-undecane, 1,2-bis(2-aminoethoxy)ethane, 1,2-bis(3-aminopropoxy)ethane, triethylene glycol-bis(3-aminopropyl)ether, polyethylene glycol-bis(3-aminopropyl)ether, 3,9-bis(3-aminopropyl)-2,4,8,10-tetraspiro-5,5-undecane, and 1,4-butanediol-bis(3-aminopropyl)ether. One type of diamine compound may be used alone, or two or more types may be used in combination. In addition, as the diamine compound, a diamine compound containing an aromatic ring is preferable, and a diamine compound containing an indane skeleton is more preferable. Examples of diamine compounds containing an indane skeleton include the diamine compounds shown in the following formulas (a2-1) to (a2-7).

In order to obtain the effects of the present invention more clearly, it is preferable that the polyimide precursor (A) contains a structural unit represented by the following formula (A-1). Usually, the structural unit represented by formula (A-1) corresponds to an amic acid structural unit and an amic acid ester structural unit.

(In formula (A-1), A ^a each independently represents a tetravalent organic group; B ^a each independently represents a divalent organic group; R ^1a and R ^2a each independently represent a hydrogen atom or a monovalent organic group; and n _a represents an integer of 5 or more and 200 or less.)

In formula (A-1), A ^a each independently represents a tetravalent organic group. The number of carbon atoms of the tetravalent organic group is preferably 6 to 40. Examples of the tetravalent organic group having 6 to 40 carbon atoms include an aromatic group in which the -COOR ^1a group and the -COOR ^2a group in formula (A-1) and the -CONH- group are in the ortho position with respect to each other, or an alicyclic aliphatic group (wherein R ^1a and R ^2a are the same as R ^1a and R ^2a in formula (A-1). Examples of such a tetravalent organic group include the following groups (a3-1) to (a3-9). In addition, a group obtained by combining two or more of the following groups (a3-1) to (a3-9) may be used as the tetravalent organic group. Among them, A is preferably a tetravalent organic group exemplified below, and more preferably a group (a3-8) and a group (a3-9). In the formula, * represents a bond.

The above-mentioned tetravalent organic group may have a substituent. Examples of the substituent include linear, branched, or cyclic alkyl groups having 1 to 10 carbon atoms, such as methyl, ethyl, propyl, and n-butyl groups; halogen atoms, such as fluorine, chlorine, and bromine; alkoxy groups having 1 to 10 carbon atoms, such as methoxy, ethoxy, and propoxy groups; hydroxy groups; and halogen-substituted alkyl groups, such as trifluoromethyl groups. Of these, alkyl groups are preferred. The above-mentioned substituents may further have a substituent (hereinafter sometimes referred to as "secondary substituents"). The substituents may be of one type or of two or more types.

In formula (A-1), each B ^a independently represents a divalent organic group. The divalent organic group preferably contains an aromatic ring. The divalent organic group more preferably contains an indane skeleton. Furthermore, the divalent organic group more preferably contains an aromatic ring in addition to the indane skeleton.

Examples of the divalent organic group include the groups (a4-1) to (a4-27) exemplified below. A group that combines two or more of the groups (a4-1) to (a4-27) may also be used as the divalent organic group. Among these, as B ^a , the groups (a4-21) to (a4-27) are preferred, and the group (a4-27) is more preferred. In the formula, * represents a bond.

The divalent organic group may have a substituent. Examples of the substituent include the same ones that the tetravalent organic group may have. The substituent may be one type or two or more types.

In formula (A-1), R ^1a and R ^2a each independently represent a hydrogen atom or a monovalent organic group. Examples of the monovalent organic group include a radical reactive group and a saturated aliphatic group having 1 to 4 carbon atoms, and the radical reactive group is preferred. As the radical reactive group, for example, a group containing an ethylenically unsaturated bond may be used. The ethylenically unsaturated bond represents a non-aromatic carbon-carbon unsaturated bond. Specific examples of the radical reactive group include a vinyl group, an allyl group, a propargyl group, an ethynyl group, a phenylethynyl group, a butenyl group, a maleimide group, a nadimide group, a (meth)acryloyl group, and a group represented by formula (A-2) described later. The term "(meth)acryloyl group" includes a methacryloyl group, an acryloyl group, and a combination thereof. It is preferable that at least one of R ^1a and R ^2a in formula (A-1) is independently a radical reactive group, and it is more preferable that both are radical reactive groups. As the radical reactive group, a group represented by the following formula (A-2) is particularly preferred.

(In formula (A-2), R ^4a , R ^5a and R ^6a each independently represent a hydrogen atom or an aliphatic hydrocarbon group having 1 to 3 carbon atoms, and p _a represents an integer of 1 to 10. * represents a bond.)

In formula (A-2), R ^4a to R ^6a each independently represent a hydrogen atom or an aliphatic hydrocarbon group having 1 to 3 carbon atoms. Examples of the aliphatic hydrocarbon group having 1 to 3 carbon atoms include an alkyl group having 1 to 3 carbon atoms. Examples of the alkyl group having 1 to 3 carbon atoms include a methyl group, an ethyl group, an n-propyl group, and a 2-propyl group, and among these, a methyl group is preferable.

In formula (A-2), p _a represents an integer of 1 to 10, preferably an integer of 1 to 5, more preferably an integer of 1 to 3, and even more preferably 2.

The saturated aliphatic groups having 1 to 4 carbon atoms exemplified by R ^1a and R ^2a are preferably alkyl groups having 1 to 4 carbon atoms. Examples of the saturated aliphatic groups having 1 to 4 carbon atoms include a methyl group, an ethyl group, an n-propyl group, a 2-propyl group, and an n-butyl group.

In formula (A-1), it is preferable that at least one of R ^1a and R ^2a is independently a radical reactive group, it is more preferable that at least one of R ^{1a and R 2a is a group represented by formula (A-2), and it is further preferable that both of R 1a} and R ^2a are groups represented by formula (A-2).

In formula (A-1), n _a usually represents an integer of 5 to 200, preferably an integer of 5 to 150, more preferably an integer of 5 to 100, and further preferably an integer of 5 to 70.

It is further preferred that the polyimide precursor (A) contains a structural unit represented by formula (A-3).

(In formula (A-3), A ^1a each independently represents a tetravalent organic group; R ^11a and R ^12a each independently represent a hydrogen atom or a monovalent organic group; R ^13a each independently represent a hydrogen atom or a methyl group; Xa each independently represent a single bond, a group represented by formula (a5-1) below, or a group represented by formula (a5-2); Xb each independently represent a single bond, a group represented by formula (a5-3), or a group represented by formula (a5-4); m _a1 represents an integer of 1 to 5; and n _a1 represents an integer of 5 or more and 200 or less.)

(In formulas (a5-1) to (a5-4), * represents a bond.)

In formula (A-3), A ^1a each independently represents a tetravalent organic group. A ^1a is the same as A ^a in formula (A-1).

In formula (A-3), R ^11a and R ^12a each independently represent a hydrogen atom or a monovalent organic group. R ^11a and R ^12a are the same as R ^1a and R ^2a in formula (A-1).

In formula (A-3), Xa each independently represents a single bond, a group represented by formula (a5-1), or a group represented by formula (a5-2). Examples of the group represented by formula (a5-1) include a 1,2-phenylene group, a 1,3-phenylene group, and a 1,4-phenylene group. Examples of the group represented by formula (a5-2) include the following groups (a5-2-1) to (a5-2-6). Of these, Xa is preferably a group represented by formula (a5-2), and more preferably a group represented by formula (a5-2-1). In the formula, * represents a bond.

In formula (A-3), Xb each independently represents a single bond, a group represented by formula (a5-3), or a group represented by formula (a5-4). Examples of the group represented by formula (a5-3) include a 1,2-phenylene group, a 1,3-phenylene group, and a 1,4-phenylene group. Examples of the group represented by formula (a5-4) include the following groups (a5-4-1) to (a5-4-3). Of these, Xb is preferably a group represented by formula (a5-4), and more preferably a group represented by formula (a5-4-1). In the formula, * represents a bond.

In formula (A-3), R ^13a each independently represents a hydrogen atom or a methyl group, and preferably represents a methyl group.

In formula (A-3), m _a1 represents an integer of 1 to 5, preferably an integer of 1 to 3, more preferably 2 or 3, and even more preferably 3.

In formula (A-3), n _a1 represents an integer of 5 or more and 200 or less, and is the same as n _a in formula (A-1).

It is particularly preferable that the polyimide precursor (A) contains a structural unit represented by the following formula (A-4).

(In formula (A-4), A ^2a each independently represents a tetravalent organic group; R ^21a and R ^22a each independently represent a hydrogen atom or a group represented by formula (A-5) below; and n _a2 represents an integer of 5 or more and 200 or less.)

(In formula (A-5), R ^14a , R ^15a and R ^16a each independently represent a hydrogen atom or an aliphatic hydrocarbon group having 1 to 3 carbon atoms; p _a1 represents an integer of 1 to 10. * represents a bond.)

In formula (A-4), each A ^2a independently represents a tetravalent organic group. A ^2a is the same as ^Aa in formula (A-1).

In formula (A-4), R ^21a and R ^22a each independently represent a hydrogen atom or a group represented by formula (A-5), with the group represented by formula (A-5) being preferred. In the group represented by formula (A-5), R ^14a to R ^16a each independently represent a hydrogen atom or an aliphatic hydrocarbon group having 1 to 3 carbon atoms. R ^14a to R ^16a are the same as R ^4a to R ^6a in formula (A-2).

In formula (A-5), p _a1 represents an integer of 1 to 10. p _a1 is the same as p _a in formula (A-2).

In formula (A-4), n _a2 represents an integer of 5 or more and 200 or less. n _a2 is the same as n _a in formula (A-1).

The polyimide precursor (A) may contain any structural unit other than the above-mentioned amic acid structural unit and amic acid ester structural unit. Thus, the polyimide precursor (A) may be a copolymer containing the structural unit represented by formula (A-1) and any structural unit. In particular, the polyimide precursor (A) preferably contains a large amount of amic acid structural units and amic acid ester structural units, and therefore, it is preferable that the amount of any structural unit is small. For example, the mass of the amic acid structural unit and the amic acid ester structural unit is preferably 50 mass% or more, more preferably 70 mass% or more, and even more preferably 90 mass% or more, based on the total mass of the polyimide precursor (A) (100%). The polyimide precursor (A) may contain only the above-mentioned amic acid structural unit and/or amic acid ester structural unit as a repeating unit, and therefore may not contain any structural unit. The amic acid structural unit and/or amic acid ester structural unit contained in the polyimide precursor (A) may be one type or two or more types.

Specific examples of the polyimide precursor (A) include the following compounds (a6-1) to (a6-4). However, the polyimide precursor (A) is not limited to these specific examples. In the formula, n _a3 to n _a6 each represent an integer of 5 to 200.

From the viewpoint of obtaining a significant effect of the present invention, the weight average molecular weight of the (A) polyimide precursor is preferably 5,000 or more, more preferably 10,000 or more, and even more preferably 50,000 or more, and is preferably 1,000,000 or less, more preferably 500,000 or less, and even more preferably 200,000 or less. The weight average molecular weight of the resin can be measured as a polystyrene-equivalent value by gel permeation chromatography (GPC).

The method for producing the polyimide precursor (A) is not particularly limited. The polyimide precursor (A) can be produced, for example, by a method including reacting a tetracarboxylic dianhydride with a diamine compound. Specific examples of the method for producing the polyimide precursor (A) include the production methods described in JP-A-2015-209461, JP-A-2015-214680, JP-A-2017-219850, and JP-A-2018-146964.

The amount of (A) polyimide precursor is preferably 10% by mass or more, more preferably 20% by mass or more, even more preferably 30% by mass or more, 40% by mass or more, 50% by mass or more, 60% by mass or more, or 70% by mass or more, and is preferably 95% by mass or less, more preferably 90% by mass or less, and even more preferably 85% by mass or less, based on 100% by mass of the non-volatile components of the photosensitive resin composition. When the amount of (A) polyimide precursor is within the above range, the resolution and film residual property can be particularly good, and usually undercut can be effectively reduced.

[(B) Crosslinking Agent]
The photosensitive resin composition according to this embodiment contains a crosslinking agent (B) as the component (B). The crosslinking agent (B) does not include those corresponding to the polyimide precursor (A). When the photosensitive resin composition is irradiated with active light rays and radicals are generated from the photoradical generator (C), a crosslinking reaction of the crosslinking agent (B) occurs, and the solubility in the developer decreases. Therefore, during development, it becomes possible to selectively remove the photosensitive resin composition in areas other than those where the crosslinking reaction has progressed, and a negative pattern can be advantageously formed. The crosslinking agent (B) may be used alone or in combination of two or more.

As the (B) crosslinking agent, a compound capable of proceeding with a crosslinking reaction upon exposure can be used. As such a (B) crosslinking agent, a compound containing an ethylenically unsaturated bond is preferable. Furthermore, as the (B) crosslinking agent, a compound containing an ethylenically unsaturated bond, in which at least one carbon atom at the α-position of the ethylenically unsaturated bond is bonded to a carbonyl group or an aromatic group, is more preferable. The carbon atom at the α-position of the ethylenically unsaturated bond refers to the first carbon atom adjacent to the carbon atom bonded by a carbon-carbon unsaturated bond.

It is preferable that the (B) crosslinking agent contains a group containing an ethylenically unsaturated bond. Hereinafter, the "group containing an ethylenically unsaturated bond" may be referred to as the "ethylenically unsaturated group". The ethylenically unsaturated group is usually a monovalent group, and examples thereof include a vinyl group, an allyl group, a propargyl group, a butenyl group, an ethynyl group, a phenylethynyl group, a maleimide group, a nadiimide group, and a (meth)acryloyl group. From the viewpoint of the reactivity of photoradical polymerization, a (meth)acryloyl group and a phenylethynyl group are preferred, and a (meth)acryloyl group is particularly preferred. Since the (B) crosslinking agent contains an ethylenically unsaturated bond, photoradical polymerization is possible, but in order to perform photoradical polymerization under general conditions, a compound having a carbonyl group or an aromatic group at at least one of the α positions of the ethylenically unsaturated bond is preferred. The number of ethylenically unsaturated bonds per molecule of the (B) crosslinking agent is preferably one or more, more preferably two or more. Furthermore, when (B) the crosslinking agent contains two or more ethylenically unsaturated groups per molecule, those ethylenically unsaturated groups may be the same or different.

The crosslinking agent (B) is preferably a compound represented by the following formula (B-1):

(In formula (B-1), R ^1b each independently represents a hydrogen atom or a linear or branched alkyl group having 1 to 4 carbon atoms; Z ^1b each independently represents a linear or branched alkylene group having 1 to 20 carbon atoms which may contain an oxygen atom, an arylene group which may contain an oxygen atom, or a linear or branched alkenylene group having 2 to 20 carbon atoms which may contain an oxygen atom; A ^1b represents a linear, cyclic or branched organic group having 1 to 10 carbon atoms and a valence of n _b ; and n _b represents an integer of 2 to 6.)

In formula (B-1), R ^1b each independently represents a hydrogen atom or a linear or branched alkyl group having 1 to 4 carbon atoms. Examples of the linear or branched alkyl group having 1 to 4 carbon atoms include a methyl group, an ethyl group, a propyl group, an isopropyl group, a 1-butyl group, a s-butyl group, and a t-butyl group. Of these, a hydrogen atom or a methyl group is preferable as R ^1b .

In formula (B-1), each Z ^1b independently represents a linear or branched alkylene group having 1 to 20 carbon atoms which may contain an oxygen atom, an arylene group which may contain an oxygen atom, or a linear or branched alkenylene group having 2 to 20 carbon atoms which may contain an oxygen atom.

The linear or branched alkylene group having 1 to 20 carbon atoms is preferably a linear or branched alkylene group having 1 to 10 carbon atoms, more preferably a linear or branched alkylene group having 1 to 6 carbon atoms. Examples of such alkylene groups include a methylene group, an ethylene group, a propylene group, a butylene group, a pentylene group, and a hexylene group, and a methylene group is preferred. The alkylene group may also be an oxyalkylene group containing an oxygen atom, and specific examples of such groups include those shown in the following formulas (b1-1) to (b1-6). In the formulas, "*" represents a bond, and n _b1 to n _b6 represent integers of 1 to 23.

The arylene group which may contain an oxygen atom is preferably an arylene group having 6 to 20 carbon atoms, more preferably an arylene group having 6 to 15 carbon atoms, and even more preferably an arylene group having 6 to 10 carbon atoms. Examples of such an arylene group include a phenylene group and a naphthylene group. The arylene group may also contain an oxygen atom, and specific examples of such groups include those shown in the following formulas (b2-1) to (b2-2). In the formulas, "*" represents a bond, and n _b7 and n _b8 represent integers of 1 to 23.

As the linear or branched alkenylene group having 2 to 20 carbon atoms which may contain an oxygen atom, a linear or branched alkenylene group having 2 to 10 carbon atoms is preferred, and a linear or branched alkenylene group having 2 to 6 carbon atoms is more preferred. Examples of such an alkenylene group include an ethenylene group, a propenylene group, a butenylene group, a pentenylene group, and a hexenylene group. The alkenylene group may also be an oxyalkenylene group containing an oxygen atom, and specific examples of such groups include those shown in the following formulae (b3-1) and (b3-2). In the formulae, "*" represents a bond, and n _b9 to n _b10 represent integers of 1 to 23. As the alkenylene group, a propenylene group is preferred.

Among these, Z ^1b is preferably a linear or branched alkylene group having 1 to 20 carbon atoms which may contain an oxygen atom, and more preferably an oxyalkylene group or a methylene group.

In formula (B-1), A ^1b represents a linear, cyclic or branched n _b- valent organic group having 1 to 10 carbon atoms. Examples of the n b-valent organic group include an n _b - _valent hydrocarbon group which may contain an oxygen atom, an n _b -valent group derived from bisphenol, an n _b- valent group derived from fluorene, an n _b- valent group derived from tricyclodecane, or an n _b- valent group derived from an isocyanuric group. Examples of the n _b -valent hydrocarbon group which may contain an oxygen atom include an n b-valent aliphatic hydrocarbon group which may contain an oxygen atom, and an n _b -valent aromatic hydrocarbon group which may contain an oxygen atom, and an n _b -valent aliphatic hydrocarbon group which may contain an oxygen atom is preferred. For example, when n _{b is} 2, A ^1b is preferably an alkylene group such as a methylene group or an ethylene group; an alkyleneoxyalkylene group such as a methyleneoxymethylene group; or the like. Specific examples of the group represented by A ^1b include those shown in the following formulas (b4-1) to (b4-7). In the formula, "*" represents a bond.

In formula (B-1), _nb represents an integer of 2 to 6, preferably an integer of 2 to 5, more preferably an integer of 2 to 4, and further preferably 2 or 3.

The crosslinking agent (B) may be a compound represented by the following formula (B-2):

In formula (B-2), R ^2b each independently represents a hydrogen atom or a methyl group, and is preferably a methyl group.

Specific examples of the (B) crosslinking agent include the following compounds (b5-1) to (b5-11). However, the (B) crosslinking agent is not limited to these.

(B) The crosslinking agent may be a commercially available product. Examples of commercially available products include NK Ester-D-TMP, 4G, 9G, 14G, 23G, DCP, TMPT, and A-TMPT manufactured by Shin-Nakamura Chemical Co., Ltd.; and SR209 manufactured by Tomoe Engineering Co., Ltd.

The amount of (B) crosslinking agent is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, even more preferably 1% by mass or more, 2% by mass or more, or 3% by mass or more, and is preferably 20% by mass or less, more preferably 15% by mass or less, and even more preferably 10% by mass or less, based on 100% by mass of the non-volatile components of the photosensitive resin composition. When the amount of (B) crosslinking agent is within the above range, the resolution and film residual property can be particularly good, and usually undercut can be effectively reduced.

The amount of (B) crosslinking agent is preferably 1 part by mass or more, more preferably 2 parts by mass or more, and even more preferably 3 parts by mass or more, and is preferably 25 parts by mass or less, more preferably 20 parts by mass or less, and even more preferably 15 parts by mass or less, relative to 100 parts by mass of (A) polyimide precursor. When the amount of (B) crosslinking agent is within the above range, the resolution and film remaining property can be particularly good, and furthermore, undercuts can usually be effectively reduced.

[(C) Photoradical generator]
The photosensitive resin composition according to the present embodiment includes a photoradical generator (C) as the component (C). This photoradical generator (C) does not include those corresponding to the above-mentioned polyimide precursor (A) or crosslinking agent (B). As the photoradical generator (C), a compound capable of generating radicals upon exposure to actinic rays can be used. The photoradical generator (C) may be used alone or in combination of two or more kinds.

(C) Examples of photoradical generators include benzophenone derivatives such as benzophenone, o-benzoylmethylbenzoate, 4-benzoyl-4'-methyldiphenyl ketone, dibenzyl ketone, and fluorenone; acetophenone derivatives such as 2,2'-diethoxyacetophenone, 2-hydroxy-2-methylpropiophenone, and 1-hydroxycyclohexylphenyl ketone; thioxanthone derivatives such as thioxanthone, 2-methylthioxanthone, 2-isopropylthioxanthone, and diethylthioxanthone; benzyl derivatives such as benzil, benzil dimethyl ketal, and benzyl-β-methoxyethyl acetal; benzoin derivatives such as benzoin and benzoin methyl ether; and 1-phenyl-1,2-butanedione-2 -(o-methoxycarbonyl)oxime, 1-phenyl-1,2-propanedione-2-(o-methoxycarbonyl)oxime, 1-phenyl-1,2-propanedione-2-(o-ethoxycarbonyl)oxime, 1-phenyl-1,2-propanedione-2-(o-benzoyl)oxime, 1,3-diphenylpropanetrione-2-(o-ethoxycarbonyl)oxime, 1-phenyl-3-ethoxypropanetrione-2-(o-benzoyl)oxime and other oximes; N-arylglycines such as N-phenylglycine; peroxides such as benzoyl perchloride; aromatic biimidazoles; titanocenes; α-(n-octanesulfonyloxyimino)-4-methoxybenzyl cyanide; and the like. Among these, oximes are preferred from the viewpoint of photosensitivity.

The (C) photoradical generator preferably contains a photoradical generator with a large molecular weight. Specifically, the (C) photoradical generator preferably contains (C-i) a photoradical generator having a molecular weight of 450 or more. Hereinafter, "(C-i) a photoradical generator having a molecular weight of 450 or more" may be referred to as "(C-i) high molecular weight radical generator". The (C) photoradical generator may contain only (C-i) high molecular weight radical generator. When (C-i) high molecular weight radical generator is used, the film retention can be improved particularly effectively.

The molecular weight of the (C-i) high molecular weight radical generator is, in detail, usually 450 or more, preferably 500 or more, more preferably 600 or more, and even more preferably 700 or more. The upper limit is preferably 3000 or less, more preferably 2500 or less, and even more preferably 2000 or less. The molecular weight of the (C) photoradical generator can be measured as a weight average molecular weight value in terms of polystyrene by gel permeation chromatography (GPC).

(C-i) Examples of high molecular weight radical generators include compounds containing a structural unit represented by formula (C-1).

(In formula (C-1), R ^1c represents an actinic ray absorbing group; R ^2c each independently represents a divalent hydrocarbon group which may have a substituent; n _c represents an integer of 1 to 10; and * represents a bond.)

In formula (C-1), R ^1c represents an active light absorbing group. The active light absorbing group represents a group capable of absorbing active light such as ultraviolet light. Examples of the active light absorbing group include a group having an aminoketone skeleton, a group having an anthraquinone skeleton, a group having a thioxanthone skeleton, a group having a ketal skeleton, a group having a benzophenone skeleton, a group having a xanthone skeleton, a group having an acetophenone skeleton, a group having a benzoin skeleton, a group having a thioxanthone skeleton, and a group having a benzoate skeleton.

Specific examples of active light absorbing groups include the groups represented by (i) to (vii) below. Among these, the active light absorbing group is preferably either (i) or (ii). In the formula, * represents a bond.

In formula (C-1), R ^2c each independently represents a divalent hydrocarbon group which may have a substituent. Examples of the divalent hydrocarbon group include a divalent aliphatic hydrocarbon group and a divalent aromatic hydrocarbon group. From the viewpoint of obtaining the effects of the present invention remarkably, a divalent aliphatic hydrocarbon group is preferable.

As the divalent aliphatic hydrocarbon group, a divalent saturated aliphatic hydrocarbon group is preferred. Examples of the divalent aliphatic hydrocarbon group include an alkylene group and an alkenylene group, and an alkylene group is preferred. The alkylene group may be linear, branched, or cyclic, and a linear group is preferred. The number of carbon atoms in the alkylene group is preferably 1 to 10, more preferably 1 to 6, even more preferably 1 to 5, and particularly preferably 1 to 3. Examples of such alkylene groups include a methylene group, an ethylene group, a propylene group, a butylene group, a pentylene group, a hexylene group, and a cyclohexylene group, and an ethylene group and a methylene group are preferred. The alkenylene group may be linear, branched, or cyclic, and a linear group is preferred. The number of carbon atoms in the alkenylene group is preferably 2 to 10, more preferably 2 to 6, and even more preferably 2 to 5.

Examples of divalent aromatic hydrocarbon groups include arylene groups and heteroarylene groups. The number of carbon atoms in the arylene group and heteroarylene group is preferably 6 to 20, and more preferably 6 to 10.

Examples of the substituents that the divalent hydrocarbon group may have include halogen atoms, alkyl groups, alkoxy groups, aryl groups, arylalkyl groups, silyl groups, acyl groups, acyloxy groups, carboxy groups, sulfo groups, cyano groups, nitro groups, hydroxy groups, mercapto groups, and oxo groups.

In formula (C-1), n _c represents an integer of 1 to 10, preferably an integer of 1 to 8, more preferably an integer of 1 to 5, and even more preferably an integer of 1 to 3.

(C-i) The high molecular weight radical generator preferably contains either a compound represented by the following formula (C-2) or a compound represented by the following formula (C-3).

(In formula (C-2), R ^11c each independently represent an actinic ray absorbing group; R ^12c each independently represent a divalent hydrocarbon group which may have a substituent; R ¹³ represents an m _c -valent hydrocarbon group; n _c1 represents an integer from 1 to 10; and m _c represents an integer from 1 to 4.
In formula (C-3), R ^21c and R ^23c each independently represent an actinic ray absorbing group; R ^22c each independently represent a divalent hydrocarbon group which may have a substituent; and n _c2 represents an integer of 1 to 10.

In formula (C-2), each R ^11c independently represents an actinic ray absorbing group, which is the same as ^{the actinic ray absorbing group represented by R 1c in} formula (C-1).

In formula (C-2), R ^12c each independently represents a divalent hydrocarbon group which may have a substituent. R ^12c is the same as the divalent hydrocarbon group which may have a substituent represented by R ^2c in formula (C-1).

In formula (C-2), R ^13c represents an m _c -valent hydrocarbon group. Examples of the m _c -valent hydrocarbon group include an m _c -valent aliphatic hydrocarbon group and an m _c -valent aromatic hydrocarbon group, with an m _c -valent aliphatic hydrocarbon group being preferred. For example, when m _c is 3, R ^13c is preferably a trivalent group obtained by removing three hydrogen atoms from an alkane. Specific examples of the group represented by R ^13c include groups represented by the following formula (c1-1). In the formula, "*" represents a bond.

In formula (C-2), n _c1 represents an integer of 1 to 10, preferably an integer of 1 to 8, more preferably an integer of 1 to 5, and even more preferably an integer of 1 to 3.

In formula (C-2), _mc represents an integer of 1 to 4, preferably an integer of 1 to 3, and more preferably 3.

In formula (C-3), R ^21c and R ^23c each independently represent an actinic ray absorbing group, ^which is the same as ^{the actinic ray absorbing group represented by R 1c in} formula (C-1).

In formula (C-3), each R ^22c independently represents a divalent hydrocarbon group which may have a substituent. R ^22c is the same as the divalent hydrocarbon group which may have a substituent represented by R ^2c in formula (C-1).

In formula (C-3), n _c2 represents an integer of 1 to 10, preferably an integer of 1 to 8, more preferably an integer of 1 to 5, and even more preferably an integer of 1 to 3.

Specific examples of the (C-i) high molecular weight radical generator include the following compounds. However, the (C-i) high molecular weight radical generator is not limited to these specific examples. a, b, c, and d each represent an integer from 1 to 10.

The amount of the high molecular weight radical generator (C-i) is preferably 0.1% by mass or more, more preferably 1% by mass or more, even more preferably 2% by mass or more, 3% by mass or more, or 4% by mass or more, and is preferably 20% by mass or less, more preferably 15% by mass or less, and even more preferably 10% by mass or less, based on 100% by mass of the non-volatile components of the photosensitive resin composition. When the amount of the high molecular weight radical generator (C-i) is within the above range, the resolution and film retention can be particularly good, and usually undercut can be effectively reduced. It is particularly effective in improving film retention.

(C) The photoradical generator may be a commercially available product. Examples of commercially available products include "Omnirad 379EG" and "Omnirad 819" manufactured by IGM, and "Irgacure OXE-01" and "Irgacure OXE-02" manufactured by BASF. Examples of commercially available products of the high molecular weight radical generator (C-i) include "Omnipol 910", "Omnipol TP", and "Omnipol 9210" manufactured by IGM.

The amount of (C) photoradical generator is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, even more preferably 1% by mass or more, and is preferably 20% by mass or less, more preferably 15% by mass or less, even more preferably 10% by mass or less, based on 100% by mass of the nonvolatile components of the photosensitive resin composition. When the amount of (C) photoradical generator is within the above range, the resolution and film residual property can be particularly good, and usually undercut can be effectively reduced.

The amount of (C) photoradical generator is preferably 0.1 parts by mass or more, more preferably 0.5 parts by mass or more, and even more preferably 1 part by mass or more, and is preferably 40 parts by mass or less, more preferably 30 parts by mass or less, and even more preferably 20 parts by mass or less, relative to 100 parts by mass of (A) polyimide precursor. When the amount of (C) photoradical generator is within the above range, the resolution and film remaining property can be particularly good, and usually undercut can be effectively reduced.

The amount of (C) photoradical generator is preferably 1 part by mass or more, more preferably 5 parts by mass or more, even more preferably 10 parts by mass or more, and is preferably 200 parts by mass or less, more preferably 150 parts by mass or less, even more preferably 120 parts by mass or less, relative to 100 parts by mass of (B) crosslinking agent. When the amount of (C) photoradical generator is within the above range, the resolution and film remaining property can be particularly good, and usually undercut can be effectively reduced.

The amount of (C) photoradical generator is preferably 0.1 parts by mass or more, more preferably 0.5 parts by mass or more, and even more preferably 1 part by mass or more, relative to 100 parts by mass of the total of (A) polyimide precursor and (B) crosslinking agent, and is preferably 30 parts by mass or less, more preferably 20 parts by mass or less, and even more preferably 15 parts by mass or less. When the amount of (C) photoradical generator is within the above range, the resolution and film remaining property can be particularly good, and usually undercut can be effectively reduced.

(D) High molecular weight sensitizer
The photosensitive resin composition according to the present embodiment includes a (D) high molecular weight sensitizer (i.e., a (D) photosensitizer having a molecular weight of 400 or more) as the (D) component. The (D) high molecular weight sensitizer does not include the above-mentioned (A) polyimide precursor, (B) crosslinking agent, or (C) photoradical generator. In general, a photosensitizer such as a (D) high molecular weight sensitizer can be excited by receiving light, but the photosensitizer itself does not generate radicals. In addition, when the photosensitizer is excited, it can usually transfer its energy to a (C) photoradical generator. Then, the (C) photoradical generator that has received the energy can generate radicals. The photosensitive resin composition according to the present embodiment includes a (D) high molecular weight sensitizer having a molecular weight of 400 or more as the photosensitizer. The (D) high molecular weight sensitizer may be used alone or in combination of two or more.

The molecular weight of the (D) high molecular weight sensitizer is usually 400 or more, preferably 405 or more, and more preferably 410 or more. The upper limit is preferably 3000 or less, more preferably 2500 or less, and even more preferably 2000 or less. The molecular weight of the photosensitizer such as (D) high molecular weight sensitizer can be measured as a weight average molecular weight value in terms of polystyrene by gel permeation chromatography (GPC).

(D) The maximum absorption wavelength of the high molecular weight sensitizer is preferably between 300 nm and 450 nm, more preferably between 330 nm and 420 nm, and even more preferably between 350 nm and 400 nm.

(D) The lowest excited triplet energy level of the high molecular weight sensitizer is preferably 60 kcal/mol to 70 kcal/mol, more preferably 60 kcal/mol to 65 kcal/mol, and particularly preferably 60 kcal/mol to 63 kcal/mol.

From the viewpoint of obtaining the effect of the present invention more significantly, the (D) high molecular weight sensitizer preferably contains a tertiary amino group in the molecule, and more preferably contains a tertiary amino group at the end of the molecule. The number of tertiary amino groups contained in one molecule of the (D) high molecular weight sensitizer is preferably 1 or more, more preferably 2 or more, and is preferably 10 or less, more preferably 5 or less. As the tertiary amino group, a tertiary alkylamino group is preferable. As the tertiary amino group, for example, a dimethylamino group, a diethylamino group, etc. can be mentioned, and the dimethylamino group is preferable. When the (D) high molecular weight sensitizer contains two or more tertiary amino groups, the tertiary amino groups may be the same or different.

From the viewpoint of obtaining the effect of the present invention more significantly, it is preferable that the (D) high molecular weight sensitizer contains an aminobenzoyl group in the molecule, and more preferably contains an aminobenzoyl group at the end of the molecule. The number of aminobenzoyl groups contained in one molecule of the (D) high molecular weight sensitizer is preferably 1 or more, more preferably 2 or more, and also preferably 10 or less, more preferably 5 or less. As the aminobenzoyl group, a tertiary alkylaminobenzoyl group is preferable. As the aminobenzoyl group, for example, a dimethylaminobenzoyl group, a diethylaminobenzoyl group, etc. can be mentioned, and a dimethylaminobenzoyl group is preferable. When the (D) high molecular weight sensitizer contains two or more aminobenzoyl groups, those aminobenzoyl groups may be the same or different.

(D) The high molecular weight sensitizer preferably contains a compound represented by formula (D-1).

(In formula (D-1), R ^1d , R ^2d , R ^5d , and R ^6d each independently represent an alkyl group having 1 to 6 carbon atoms which may have a substituent; R ^3d each independently represent a divalent group selected from the group consisting of an alkylene group having 1 to 6 carbon atoms which may have a substituent, an oxygen atom, -NR ^7d -, and a combination thereof, R ^7d represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms; R ^4d represents a divalent group selected from the group consisting of an alkylene group having 1 to 6 carbon atoms which may have a substituent, an oxygen atom, and a combination thereof; and r _d represents an integer of 1 to 10.)

In formula (D-1), R ^1d , R ^2d , R ^5d , and R ^6d each independently represent an alkyl group having 1 to 6 carbon atoms which may have a substituent. The alkyl group may be linear, branched, or cyclic, and is preferably linear. The alkyl group having 1 to 6 carbon atoms is preferably an alkyl group having 1 to 5 carbon atoms, more preferably an alkyl group having 1 to 3 carbon atoms, and even more preferably a methyl group.

In formula (D-1), R ^3d each independently represents a divalent group selected from the group consisting of an alkylene group having 1 to 6 carbon atoms which may have a substituent, an oxygen atom, -NR ^7d -, and a combination thereof.

R ^7d represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. Examples of the alkyl group having 1 to 3 carbon atoms include a methyl group, an ethyl group, and a propyl group. R ^7d is preferably an alkyl group having 1 to 3 carbon atoms, more preferably an alkyl group having 1 or 2 carbon atoms, and even more preferably a methyl group.

The alkylene group in R ^3d may be linear, branched, or cyclic, and is preferably linear. The alkylene group having 1 to 6 carbon atoms is preferably an alkylene group having 1 to 5 carbon atoms, more preferably an alkylene group having 1 to 3 carbon atoms, and even more preferably an alkylene group having 1 or 2 carbon atoms, or an ethylene group.

Examples of the divalent group consisting of a combination of an alkylene group having 1 to 6 carbon atoms, an oxygen atom, and -NR ^7d - in R ^3d include divalent groups consisting of an oxyalkylene alkylamino structure, such as an oxymethylene methylamino group, an oxyethylene methylamino group, an oxypropylene methylamino group, an oxybutylene methylamino group, an oxypentylene methylamino group, an oxyhexylene methylamino group, an oxymethylene ethylamino group, an oxyethylene ethylamino group, an oxypropylene ethylamino group, an oxybutylene ethylamino group, an oxypentylene ethylamino group, and an oxyhexylene ethylamino group; divalent groups consisting of an oxyalkylene structure, such as an oxymethylene group, an oxyethylene group, an oxypropylene group, an oxybutylene group, an oxypentylene group, and an oxyhexylene group; a methyleneoxy group, an ethyleneoxy group, a propyleneoxy group, a butyleneoxy group, a pentyleneoxy group, and a hexyleneoxy group. divalent groups having an alkyleneoxy structure, such as an oxymethyleneoxy group, an oxyethyleneoxy group, an oxypropyleneoxy group, an oxybutyleneoxy group, an oxypentyleneoxy group, an oxyhexyleneoxy group, etc.; divalent groups having an alkyleneoxyalkylene structure, such as a methyleneoxymethylene group, an ethyleneoxyethylene group, a propyleneoxypropylene group, a butyleneoxybutylene group, a pentyleneoxypentylene group, an hexyleneoxyhexylene group, etc.; divalent groups having an alkyleneoxyalkyleneoxy structure, such as a methyleneoxymethylene group, an ethyleneoxyethyleneoxy group, a propyleneoxypropyleneoxy group, a butyleneoxybutylene group, a pentyleneoxypentylene group, an hexyleneoxyhexylene group, etc.

Among these, from the viewpoint of obtaining the effects of the present invention remarkably, R ^3d is preferably either a divalent group having an oxyalkylene alkylamino structure or a divalent group having an oxyalkyleneoxy structure. As the divalent group having an oxyalkylene alkylamino structure, an oxyethylene methylamino group is preferable. As the divalent group having an oxyalkyleneoxy structure, an oxyethylene oxy group is preferable.

In formula (D-1), R ^4d represents a divalent group selected from the group consisting of an alkylene group having 1 to 6 carbon atoms which may have a substituent, an oxygen atom, and a combination thereof. The alkylene group having 1 to 6 carbon atoms in R ^4d is the same as the alkylene group having 1 to 6 carbon atoms in R ^3d . In addition, the divalent group consisting of a combination of an alkylene group having 1 to 6 carbon atoms and an oxygen atom in R ^4d is the same as the divalent group consisting of a combination of an alkylene group having 1 to 6 carbon atoms and an oxygen atom in R ^3d .

From the viewpoint of obtaining the remarkable effects of the present invention, R ^4d is preferably a divalent group having an alkyleneoxy structure. As the divalent group having an alkyleneoxy structure, an ethyleneoxy group is preferable.

In formula (D-1), r _d represents an integer of 1 to 10, preferably an integer of 1 to 5, more preferably an integer of 1 to 4, and even more preferably 3 or 4.

In formula (D-1), the nitrogen atom bonded to the benzene ring may be bonded at the ortho, meta, or para position, and from the viewpoint of obtaining a significant effect of the present invention, it is preferable that the nitrogen atom be bonded at the para position.

In formula (D-1), the alkyl groups having 1 to 6 carbon atoms represented by R ^1d , R ^2d , R ^5d , and R ^6d and the alkylene groups having 1 to 6 carbon atoms represented by R ^3d and R ^4d may have a substituent. Examples of the substituent include a halogen atom, an alkoxy group, an aryl group, an arylalkyl group, a silyl group, an acyl group, an acyloxy group, a carboxy group, a sulfo group, a cyano group, a nitro group, a hydroxy group, a mercapto group, and an oxo group.

Specific examples of the high molecular weight sensitizer (D) include compounds represented by the following formulas (d1-1) and (d1-2). However, the high molecular weight sensitizer (D) is not limited to these specific examples. r _d1 represents 3 or 4.

(D) The high molecular weight sensitizer may be a commercially available product. Examples of commercially available products include "Omnipol ASA" and "Esacure A 198" manufactured by IGM.

The amount of (D) high molecular weight sensitizer is preferably 0.5% by mass or more, more preferably 1% by mass or more, even more preferably 5% by mass or more, and preferably 15% by mass or less, more preferably 13% by mass or less, even more preferably 10% by mass or less, based on 100% by mass of the non-volatile components of the photosensitive resin composition. When the amount of (D) high molecular weight sensitizer is within the above range, the resolution and film remaining property can be particularly good, and usually undercut can be effectively reduced.

The amount of (D) high molecular weight sensitizer is preferably 0.1 parts by mass or more, more preferably 1 part by mass or more, and even more preferably 5 parts by mass or more, and is preferably 30 parts by mass or less, more preferably 20 parts by mass or less, and even more preferably 15 parts by mass or less, per 100 parts by mass of (A) polyimide precursor. When the amount of (D) high molecular weight sensitizer is within the above range, the resolution and film remaining property can be particularly good, and usually undercut can be effectively reduced.

The amount of (D) high molecular weight sensitizer is preferably 10 parts by mass or more, more preferably 30 parts by mass or more, even more preferably 50 parts by mass or more, and is preferably 300 parts by mass or less, more preferably 200 parts by mass or less, even more preferably 150 parts by mass or less, per 100 parts by mass of (B) crosslinking agent. When the amount of (D) high molecular weight sensitizer is within the above range, the resolution and film remaining property can be particularly good, and usually undercut can be effectively reduced.

The amount of (D) high molecular weight sensitizer is preferably 10 parts by mass or more, more preferably 30 parts by mass or more, even more preferably 50 parts by mass or more, and is preferably 1000 parts by mass or less, more preferably 800 parts by mass or less, even more preferably 600 parts by mass or less, relative to 100 parts by mass of (C) photoradical generator. When the amount of (D) high molecular weight sensitizer is within the above range, the resolution and film remaining property can be particularly good, and furthermore, undercut can usually be effectively reduced.

The amount of (D) high molecular weight sensitizer is preferably 0.1 parts by mass or more, more preferably 1 part by mass or more, and even more preferably 3 parts by mass or more, relative to 100 parts by mass of the total of (A) polyimide precursor, (B) crosslinking agent, and (C) photoradical generator, and is preferably 30 parts by mass or less, more preferably 20 parts by mass or less, and even more preferably 10 parts by mass or less. When the amount of (D) high molecular weight sensitizer is within the above range, the resolution and film remaining property can be particularly good, and usually undercut can be effectively reduced.

(E) Optional Additives
The photosensitive resin composition according to the present embodiment may contain an optional additive (E) as an optional component in addition to the above-mentioned components (A) to (D). The optional additive (E) as component (E) may be used alone or in combination of two or more kinds.

(E) Optional additives include, for example, photopolymerization initiator aids. Examples of photopolymerization initiator aids include tertiary amines such as N,N-dimethylaminobenzoic acid ethyl ester, N,N-dimethylaminobenzoic acid isoamyl ester, pentyl-4-dimethylaminobenzoate, triethylamine, and triethanolamine.

In addition, examples of optional additives (E) include photosensitizers having a molecular weight of less than 400 (hereinafter sometimes referred to as "low molecular weight sensitizers"); adhesion aids; surfactants such as fluorine-based surfactants, nonionic surfactants, cationic surfactants, anionic surfactants, and silicone-based surfactants; thermoplastic resins; colorants such as phthalocyanine blue, phthalocyanine green, iodine green, diazo yellow, crystal violet, titanium oxide, carbon black, and naphthalene black; polymerization inhibitors such as hydroquinone, phenothiazine, methylhydroquinone, hydroquinone monomethyl ether, catechol, and pyrogallol; thickeners such as bentone and montmorillonite; silicone-based, fluorine-based, and vinyl resin-based defoamers; flame retardants such as epoxy resins, antimony compounds, phosphorus-based compounds, aromatic condensed phosphate esters, and halogen-containing condensed phosphate esters; and thermosetting resins such as epoxy resins, phenolic resins, and cyanate ester resins.

[(F) Solvent]
The photosensitive resin composition according to the present embodiment may contain a solvent (F) as an optional component in combination with the non-volatile components (A) to (E) described above. The solvent (F) is a volatile component, and it is preferable to use one that can uniformly dissolve at least one of the components (A) to (E).

(F) Examples of solvents include ether compound solvents having 2 to 9 carbon atoms, such as dimethyl ether, diethyl ether, methyl ethyl ether, tetrahydrofuran, dioxane, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, and triethylene glycol dimethyl ether; ketone compound solvents having 2 to 6 carbon atoms, such as acetone and methyl ethyl ketone; saturated hydrocarbon compound solvents having 5 to 10 carbon atoms, such as normal pentane, cyclopentane, normal hexane, cyclohexane, methylcyclohexane, and decalin; benzene, toluene, etc. aromatic hydrocarbon compound solvents having 6 to 10 carbon atoms, such as xylene, mesitylene, and tetralin; ester compound solvents having 3 to 9 carbon atoms, such as methyl acetate, ethyl acetate, γ-butyrolactone, and methyl benzoate; halogen-containing compound solvents having 1 to 10 carbon atoms, such as chloroform, methylene chloride, and 1,2-dichloroethane; nitrogen-containing compound solvents having 2 to 10 carbon atoms, such as acetonitrile, N,N-dimethylformamide, N,N-dimethylacetamide, and N-methyl-2-pyrrolidone; and sulfur-containing compound solvents, such as dimethyl sulfoxide.

Examples of (F) solvents include N-ethyl-2-pyrrolidone, tetrahydrofuran, N,N-dimethylacetamide, dimethyl sulfoxide, hexamethylphosphoramide, pyridine, cyclopentanone, α-acetyl-γ-butyrolactone, tetramethylurea, 1,3-dimethyl-2-imidazolinone, N-cyclohexyl-2-pyrrolidone, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, methyl ethyl ketone, methyl isobutyl ketone, anisole, ethyl acetate, ethyl lactate, and butyl lactate.

(F) Solvents may be used alone or in combination of two or more.

The amount of the (F) solvent is preferably 10% by mass or more, more preferably 20% by mass or more, and even more preferably 30% by mass or more, and is preferably 99% by mass or less, more preferably 97% by mass or less, and even more preferably 95% by mass or less, when the entire photosensitive resin composition including the (F) solvent is taken as 100% by mass. The amount of the (F) solvent in the photosensitive resin composition layer of the photosensitive film is preferably 1% by mass or more, more preferably 2% by mass or more, and even more preferably 3% by mass or more, when the entire photosensitive resin composition including the (F) solvent is taken as 100% by mass, and is preferably 40% by mass or less, more preferably 35% by mass or less, and even more preferably 30% by mass or less.

[Method for producing photosensitive resin composition]
The photosensitive resin composition can be produced by a method including appropriately mixing the above-mentioned components and, if necessary, kneading or stirring the mixture with a kneading device such as a triple roll mill, a ball mill, a bead mill, or a sand mill, or with a stirring device such as a super mixer or a planetary mixer.

[Characteristics and uses of photosensitive resin composition]
The photosensitive resin composition according to the present embodiment can have excellent resolution. Therefore, the photosensitive resin composition according to the present embodiment can form a small hole by exposure and development. The degree of resolution can be evaluated by the opening diameter of the limiting opening via.

For example, a photosensitive resin composition layer having a thickness of 30 μm is prepared using a photosensitive resin composition. The photosensitive resin composition layer is exposed to light using a mask that draws round holes (via holes) with an exposure pattern of 20 μm, 30 μm, 40 μm, 50 μm, 60 μm, 70 μm, 80 μm, 90 μm, and 100 μm, and developed to form round holes. The bottom of the round hole is then observed to identify the round hole (threshold opening via) with the smallest opening diameter that can be opened without residue or peeling. The photosensitive resin composition according to this embodiment can make the opening diameter of this identified round hole (threshold opening via) preferably 50 μm or less, more preferably 40 μm or less, even more preferably 30 μm or less, and particularly preferably 20 μm or less. The specific method for measuring the opening diameter of the threshold opening via can be the method described in the examples below.

The photosensitive resin composition according to this embodiment can have excellent film retention. Therefore, when the photosensitive resin composition according to this embodiment is used, a reduction in thickness due to exposure and development can be suppressed, and a high film retention rate can be obtained. For example, a photosensitive resin composition layer is produced using a photosensitive resin composition. The photosensitive resin composition layer is exposed and developed to form a round hole, and then cured to obtain a cured layer. In this case, the ratio of the thickness of the cured layer based on the thickness of the photosensitive resin composition layer before exposure (i.e., the film retention rate) is preferably 50% or more, more preferably 70% or more, and may be 80% or more or 85% or more. A specific method for measuring the film retention rate can be adopted, as described in the Examples below.

In addition, since the photosensitive resin composition has excellent film retention, when a hole is formed in the photosensitive resin composition layer by exposure and development, the aspect ratio of the hole can be increased. Here, the aspect ratio represents the aspect ratio of the cross-sectional shape of the hole in a cross section of the photosensitive resin composition layer cut in the thickness direction. Specifically, the aspect ratio is the ratio obtained by dividing the depth of the hole by the opening diameter of the hole. The photosensitive resin composition according to this embodiment has excellent developability, so the opening diameter of the hole can be made small, and has excellent film retention, so the depth of the hole can be made large, making it possible to increase the aspect ratio.

The photosensitive resin composition according to this embodiment can usually reduce undercut to close to zero. For example, a photosensitive resin composition layer having a thickness of 30 μm is prepared using the photosensitive resin composition. The photosensitive resin composition layer is exposed to light and developed to form round holes. Among these round holes, the undercut of the smallest round hole (limit opening via) that can be opened without residue or peeling can be reduced to preferably 4 μm or less, more preferably less than 2 μm, and particularly preferably no undercut. A specific method for measuring the undercut can be adopted, as described in the Examples below.

According to the photosensitive resin composition of this embodiment, it is preferable to obtain a cured product having excellent dielectric properties. Usually, the photosensitive resin composition is heated after exposure and development to close the ring of the polyimide precursor (A) and obtain a cured product containing polyimide. This cured product containing polyimide usually has excellent dielectric properties and is suitable for an insulating layer. For example, when a cured product is obtained by curing the photosensitive resin composition by the method described in the examples below, the relative dielectric constant Dk of the cured product is preferably 5 or less, more preferably 4 or less, and even more preferably 3 or less. In addition, the dielectric loss tangent Df of the cured product is preferably 0.015 or less, more preferably 0.012 or less, and even more preferably 0.09 or less. The relative dielectric constant Dk and the dielectric loss tangent Df can be measured by a cavity resonance perturbation method using a measuring device ("HP8362B" manufactured by Agilent Technologies) at a measurement frequency of 5.8 GHz and a measurement temperature of 23°C.

The use of the photosensitive resin composition according to this embodiment is not particularly limited. The photosensitive resin composition according to this embodiment can be used in a wide range of applications in which photosensitive resin compositions are used, such as insulating resin sheets (photosensitive films, prepregs, etc.), silicon wafers, circuit boards (for laminates, multilayer printed wiring boards, etc.), solder resists, buffer coat films, underfill materials, die bonding materials, semiconductor encapsulants, hole filling resins, and component embedding resins. In particular, the photosensitive resin composition according to this embodiment can be used in a wide range of applications in which photosensitive resin compositions are used, such as a photosensitive resin composition for an insulating layer of a printed wiring board (a printed wiring board having a cured product of a photosensitive resin composition as an insulating layer), a photosensitive resin composition for an interlayer insulating layer (a printed wiring board in which a cured product of a photosensitive resin composition is used as an interlayer insulating layer), a photosensitive resin composition for plating (a printed wiring board in which plating is formed on a cured product of a photosensitive resin composition), a photosensitive resin composition for solder resist (a printed wiring board in which a cured product of a photosensitive resin composition is used as a solder resist), and a photosensitive resin composition for a rewiring formation layer of a wafer-level package (a wafer level package in which a cured product of a photosensitive resin composition is used as a rewiring formation layer). It can be suitably used as a photosensitive resin composition for a rewiring formation layer in a fan-out wafer-level package (a fan-out wafer-level package in which a cured product of a photosensitive resin composition is used as a rewiring formation layer), a photosensitive resin composition for a rewiring formation layer in a fan-out panel-level package (a fan-out panel-level package in which a cured product of a photosensitive resin composition is used as a rewiring formation layer), a photosensitive resin composition for a buffer coat (a semiconductor device in which a cured product of a photosensitive resin composition is used as a buffer coat), and a photosensitive resin composition for an insulating layer in a display (a display in which a cured product of a photosensitive resin composition is used as an insulating layer).

[Photosensitive film]
The photosensitive resin composition according to one embodiment of the present invention can be applied to a photosensitive film. The photosensitive film can include a support and a photosensitive resin composition layer formed on the support. The photosensitive resin composition layer contains the above-mentioned photosensitive resin composition, and preferably contains only the photosensitive resin composition. The photosensitive film may also include a support, a photosensitive resin composition layer, and a protective film in this order.

Examples of the support include polyethylene terephthalate film, polyethylene naphthalate film, polypropylene film, polyethylene film, polyvinyl alcohol film, triacetyl acetate film, etc., with polyethylene terephthalate film being particularly preferred.

Commercially available supports include, but are not limited to, polypropylene films such as Oji Paper's "Alphan MA-410" and "E-200C," Tamapoly's "GF-1" and "GF-8," and Shin-Etsu Film's polypropylene film; and polyethylene terephthalate films such as Teijin's PS series, such as "PS-25." These supports are preferably coated on the surface with a release agent, such as a silicone coating agent or a non-silicone coating agent, to facilitate removal. Examples of supports whose surfaces have been treated with such release agents include "AL-5" manufactured by Lintec. The thickness of the support is preferably in the range of 5 μm to 100 μm, and more preferably in the range of 10 μm to 50 μm.

The thickness of the photosensitive resin composition layer is not particularly limited and can be, for example, 1 μm or more and 100 μm or less. In particular, the thickness of the photosensitive resin composition layer is preferably 2 μm or more, more preferably 4 μm or more, and is preferably 50 μm or less, more preferably 30 μm or less.

The photosensitive resin composition layer may be protected by a protective film. When the photosensitive resin composition layer is protected by a protective film, the adhesion of dust and scratches to the surface of the photosensitive resin composition layer can be suppressed. As the protective film, for example, a film formed of the same material as the above-mentioned support can be used. The thickness of the protective film is not particularly limited, but is preferably in the range of 1 μm to 40 μm, more preferably in the range of 5 μm to 30 μm, and even more preferably in the range of 10 μm to 30 μm. It is preferable that the adhesive strength between the photosensitive resin composition layer and the protective film is smaller than the adhesive strength between the photosensitive resin composition layer and the support.

The photosensitive film can be produced, for example, by a method including coating a photosensitive resin composition on a support and, if necessary, drying the solvent (F).

[Semiconductor package substrate]
A semiconductor package substrate according to an embodiment of the present invention includes an insulating layer formed of the cured product of the above-mentioned photosensitive resin composition. Thus, the insulating layer includes the cured product of the photosensitive resin composition, and preferably includes only the cured product of the photosensitive resin composition. The insulating layer is preferably used as a rewiring layer, an interlayer insulating layer, a buffer coat film, or a solder resist.

In the first example, the semiconductor package substrate can be manufactured using the above-mentioned photosensitive resin composition, and the cured product of the photosensitive resin composition is used as an insulating layer. Specifically, the manufacturing method of the semiconductor package substrate according to the first example includes the following steps:
(I) forming a photosensitive resin composition layer containing the photosensitive resin composition according to this embodiment on a circuit board;
(II) a step of irradiating the photosensitive resin composition layer with actinic rays;
(III) developing the photosensitive resin composition layer;
Includes, in this order.

<Step (I)>
Examples of methods for forming the photosensitive resin composition layer include a method in which a resin varnish containing the photosensitive resin composition is directly applied onto a circuit board, and a method in which the photosensitive film is used.

When the resin varnish containing the photosensitive resin composition is applied directly onto the circuit board, (F) the solvent is dried or volatilized to form a photosensitive resin composition layer on the circuit board.

Examples of resin varnish application methods include gravure coating, microgravure coating, reverse coating, kiss reverse coating, die coating, slot die, lip coating, comma coating, blade coating, roll coating, knife coating, curtain coating, chamber gravure coating, slot orifice, spin coating, slit coating, spray coating, dip coating, hot melt coating, bar coating, applicator, air knife coating, curtain flow coating, offset printing, brush coating, and full-surface printing using screen printing.

The resin varnish may be applied in several separate applications, or in one application, or a combination of different methods may be used. Of these, the die coating method is preferred, as it provides excellent uniformity of application. In addition, to avoid contamination by foreign matter, it is preferable to carry out the application process in an environment where foreign matter is unlikely to be generated, such as a clean room.

After the resin varnish is applied, it is dried in a drying oven such as a hot air oven or far infrared oven as necessary. Drying conditions are preferably 80°C to 120°C for 3 to 13 minutes. In this way, a photosensitive resin composition layer is formed on the circuit board.

Examples of circuit boards include substrates that include a support substrate such as a glass epoxy substrate, a metal substrate, a polyester substrate, a polyimide substrate, a BT resin substrate, or a thermosetting polyphenylene ether substrate. Here, the circuit board refers to a substrate having a patterned conductor layer (circuit) formed on one or both sides of the support substrate as described above. In addition, in a multilayer printed wiring board formed by alternately laminating conductor layers and insulating layers, a substrate in which one or both sides of the outermost layer of the multilayer printed wiring board are patterned conductor layers (circuits) is also included in the circuit board referred to here. The surface of the conductor layer may be roughened in advance by blackening, copper etching, or the like.

On the other hand, when a photosensitive film is used, the photosensitive resin composition layer side of the photosensitive film is laminated to one or both sides of the circuit board using a vacuum laminator. When the photosensitive film has a protective film, the protective film is removed before lamination. Lamination can be performed by preheating the photosensitive film and the circuit board as necessary, and pressing the photosensitive resin composition layer onto the circuit board while applying pressure and heat. For photosensitive films, a method of laminating to the circuit board under reduced pressure using a vacuum lamination method is preferably used.

The lamination conditions are not particularly limited. For example, it is preferable to perform lamination under reduced pressure with a pressure bonding temperature (lamination temperature) of preferably 50°C to 140°C, a pressure bonding pressure of preferably 1 kgf/cm ² to 11 kgf/cm ² (9.8×10 ⁴ N/m ² to 107.9×10 ⁴ N/m ² ), a pressure bonding time of preferably 5 seconds to 300 seconds, and an air pressure of 20 mmHg (26.7 hPa) or less. The lamination process may be a batch type or a continuous type using a roll. The vacuum lamination method can be performed using a commercially available vacuum laminator. Examples of commercially available vacuum laminators include a vacuum applicator manufactured by Nikko Materials Co., Ltd., a vacuum pressure laminator manufactured by Meiki Seisakusho Co., Ltd., a roll type dry coater manufactured by Hitachi Industries Co., Ltd., and a vacuum laminator manufactured by Hitachi AIC Co., Ltd.

<Step (II)>
After the photosensitive resin composition layer is provided on the circuit board, an exposure step is then performed in which a predetermined portion of the photosensitive resin composition layer is irradiated with active light through a mask pattern. Examples of active light include ultraviolet light, visible light, electron beams, and X-rays, and ultraviolet light is particularly preferred. The amount of ultraviolet light is usually 10 mJ/cm ² to 1000 mJ/cm ^2. There are two types of exposure method: a contact exposure method in which a mask pattern is brought into close contact with the circuit board, and a non-contact exposure method in which exposure is performed using parallel light without contact, and either method may be used.

In step (II), a via pattern such as a round hole pattern can be used as the mask pattern. For example, a mask pattern capable of forming a latent image of a via hole having a desired via diameter (opening diameter) can be used. The via diameter (opening diameter) is preferably 100 μm or less, more preferably 50 μm or less, and even more preferably 30 μm or less. The lower limit is not particularly limited, but can be 0.1 μm or more, 0.5 μm or more, etc.

After exposure, a heat treatment may be performed as necessary. Heat treatment can quickly reduce the solubility of the exposed portion of the photosensitive resin composition layer in the developer.

<Step (III)>
After the exposure step, a development step is carried out in which the unexposed portions of the photosensitive resin composition layer are removed with a developer, whereby holes are formed in the photosensitive resin composition layer, and a desired pattern can be obtained. The development is usually carried out by wet development.

In the case of the above-mentioned wet development, the developer used is usually an alkaline solution, an aqueous developer, an organic solvent, or another developer that is safe, stable, and easy to operate. In addition, the development method may be any known method such as spraying, oscillating immersion, brushing, or scraping.

Examples of alkaline aqueous solutions used as the developer include aqueous solutions of alkali metal hydroxides such as lithium hydroxide, sodium hydroxide, and potassium hydroxide; carbonates or bicarbonates such as sodium carbonate and sodium bicarbonate; alkali metal phosphates such as sodium phosphate and potassium phosphate; and alkali metal pyrophosphates such as sodium pyrophosphate and potassium pyrophosphate; and aqueous solutions of organic bases that do not contain metal ions, such as tetraalkylammonium hydroxide. An aqueous solution of tetramethylammonium hydroxide (TMAH) is preferred because it does not contain metal ions and does not affect the semiconductor chip.

These alkaline aqueous solutions may contain additives such as surfactants and defoamers to improve the development effect. The pH of the alkaline aqueous solution is preferably in the range of 8 to 12, and more preferably in the range of 9 to 11. The base concentration of the alkaline aqueous solution is preferably 0.1% by mass to 10% by mass. The temperature of the alkaline aqueous solution can be appropriately selected according to the developability of the photosensitive resin composition layer, and is preferably 20°C to 50°C.

Organic solvents used as developers include, for example, acetone, ethyl acetate, alkoxyethanols having an alkoxy group with 1 to 4 carbon atoms, ethyl alcohol, isopropyl alcohol, butyl alcohol, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, cyclopentanone, and cyclohexanone.

The concentration of such an organic solvent is preferably 2% by mass to 90% by mass based on the total amount of the developer. The temperature of such an organic solvent can be adjusted according to the developability. Furthermore, such organic solvents can be used alone or in combination of two or more kinds. Examples of organic solvent-based developers used alone include 1,1,1-trichloroethane, N-methylpyrrolidone, N,N-dimethylformamide, cyclopentanone, cyclohexanone, methyl isobutyl ketone, and γ-butyrolactone.

When forming a pattern, two or more development methods may be used in combination, if necessary. Development methods include the dip method, the stroke method, the spray method, the high-pressure spray method, brushing, and slapping, and the high-pressure spray method is suitable for improving resolution. When using the spray method, the spray pressure is preferably 0.05 MPa to 0.3 MPa.

<Thermal curing (post-bake) process>
After the above step (III) is completed, a heat curing (post-baking) step is performed as necessary. Although the curing of the photosensitive resin composition layer may proceed in the above steps (I) to (III), the curing of the photosensitive resin composition can be further promoted by the heat curing step to obtain an insulating layer having better mechanical strength. Usually, in this heat curing step, the polyimide precursor (A) undergoes ring closure to obtain a polyimide. Examples of the heat curing step include a heating step using a clean oven. The atmosphere during heat curing may be in air or in an inert gas atmosphere such as nitrogen. The heating conditions may be appropriately selected depending on factors such as the type and content of the resin component in the photosensitive resin composition. Specific heating conditions are preferably selected in the range of 150°C to 250°C for 20 minutes to 300 minutes, more preferably 160°C to 230°C for 30 minutes to 240 minutes.

<Optional Step>
The method for producing a semiconductor package substrate may further include a drilling step and a desmearing step after forming an insulating layer as a cured photosensitive resin composition layer. These steps may be performed according to various methods known to those skilled in the art for use in the production of semiconductor package substrates.

After forming the insulating layer, if desired, a drilling process may be performed on the insulating layer formed on the circuit board to form via holes and through holes. The drilling process may be performed by known methods such as drilling, laser, plasma, etc., or by combining these methods as necessary. Among these, a drilling process using a laser such as a carbon dioxide laser or a YAG laser is preferred.

The desmear process is a process in which a desmear treatment is performed on the insulating layer. Resin residue (smear) generally adheres to the inside of openings such as via holes and through holes formed in the drilling process. Since such smears can cause poor electrical connections, it is preferable to perform a process to remove the smear (desmear treatment) in this process.

The desmearing process may be performed by a dry desmearing process, a wet desmearing process, or a combination of these.

An example of a dry desmear process is a desmear process using plasma. A desmear process using plasma can be performed using a commercially available plasma desmear process. Among commercially available plasma desmear process devices, examples suitable for use in manufacturing semiconductor package substrates include a microwave plasma device manufactured by Nissin Co., Ltd. and an atmospheric plasma etching device manufactured by Sekisui Chemical Co., Ltd.

As the wet desmear treatment, for example, a desmear treatment using an oxidizing agent solution can be mentioned. When performing the desmear treatment using an oxidizing agent solution, it is preferable to perform the swelling treatment using a swelling liquid, the oxidation treatment using an oxidizing agent solution, and the neutralization treatment using a neutralizing liquid in this order. As the swelling liquid, for example, "Swelling Dip Securigans P" and "Swelling Dip Securigans SBU" manufactured by Atotech Japan can be mentioned. The swelling treatment is preferably performed by immersing the substrate on which the via holes or the like are formed in the swelling liquid heated to 60°C to 80°C for 5 to 10 minutes. As the oxidizing agent solution, an alkaline permanganate solution is preferable, and for example, a solution in which potassium permanganate or sodium permanganate is dissolved in an aqueous solution of sodium hydroxide can be mentioned. The oxidation treatment using the oxidizing agent solution is preferably performed by immersing the substrate after the swelling treatment in the oxidizing agent solution heated to 60°C to 80°C for 10 to 30 minutes. Commercially available alkaline permanganate aqueous solutions include, for example, "Concentrate Compact CP" and "Dosing Solution Securiganth P" manufactured by Atotech Japan. The neutralization treatment using a neutralizing solution is preferably carried out by immersing the substrate after the oxidation treatment in the neutralizing solution at 30°C to 50°C for 3 to 10 minutes. The neutralizing solution is preferably an acidic aqueous solution, and a commercially available product is, for example, "Reduction Solution Securiganth P" manufactured by Atotech Japan.

When dry desmear treatment and wet desmear treatment are performed in combination, the dry desmear treatment may be performed first, or the wet desmear treatment may be performed first.

Whether the insulating layer is formed as a redistribution layer, an interlayer insulating layer, or a solder resist, a hole drilling process and a desmearing process may be performed after the thermal curing process. In addition, the manufacturing method for a semiconductor package substrate may further include a conductor layer forming process.

The conductor layer forming process is a process of forming a conductor layer on an insulating layer. The conductor layer may be formed by sputtering after the insulating layer is formed. The conductor layer may also be formed by a combination of electroless plating and electrolytic plating. Furthermore, a plating resist having a reverse pattern to the conductor layer may be formed, and the conductor layer may be formed only by electroless plating. Subsequent pattern formation methods may include, for example, subtractive methods and semi-additive methods known to those skilled in the art.

The semiconductor package substrate according to the second example can be manufactured using the above-mentioned photosensitive resin composition, and the cured product of the photosensitive resin composition is used as a rewiring formation layer. Specifically, the manufacturing method of the semiconductor package substrate according to the second example includes the following steps:
(A) a step of laminating a temporary fixing film on a substrate;
(B) a step of temporarily fixing a semiconductor chip on a temporary fixing film;
(C) forming an encapsulation layer on the semiconductor chip;
(D) peeling the substrate and the temporary fixing film from the semiconductor chip;
(E) a step of forming a rewiring formation layer as an insulating layer on the surface of the semiconductor chip from which the base material and the temporary fixing film have been peeled off;
(F) forming a rewiring layer as a conductor layer on the rewiring formation layer; and
(G) forming a solder resist layer on the rewiring layer;
The method for manufacturing a semiconductor package substrate includes:
(H) dicing the plurality of semiconductor package substrates into individual semiconductor package substrates;
may also include

<Step (A)>
Step (A) is a step of laminating a temporary fixing film on a substrate. The lamination conditions of the substrate and the temporary fixing film are not particularly limited, but for example, it is preferable to perform lamination under reduced pressure with a pressure bonding temperature (lamination temperature) of preferably 70°C to 140°C, a pressure bonding pressure of preferably 1 kgf/cm ² to 11 kgf/cm ² , a pressure bonding time of preferably 5 seconds to 300 seconds, and an air pressure of 20 mmHg or less. The lamination step may be a batch type or a continuous type using a roll. The vacuum lamination method can be performed using a commercially available vacuum laminator. Examples of commercially available vacuum laminators include a vacuum applicator manufactured by Nikko Materials Co., Ltd., a vacuum pressure laminator manufactured by Meiki Seisakusho Co., Ltd., a roll type dry coater manufactured by Hitachi Industries Co., Ltd., and a vacuum laminator manufactured by Hitachi AIC Co., Ltd.

Examples of substrates include silicon wafers; glass wafers; glass substrates; metal substrates such as copper, titanium, stainless steel, and cold-rolled steel plate (SPCC); substrates such as FR-4 substrates in which glass fibers are impregnated with epoxy resin or the like and then heat-cured; and substrates made of bismaleimide triazine resins such as BT resin.

The temporary fixing film can be made of any material that can be peeled off from the semiconductor chip and can temporarily fix the semiconductor chip. Commercially available products include "Riva Alpha" manufactured by Nitto Denko Corporation.

<Step (B)>
Step (B) is a step of temporarily fixing the semiconductor chip on the temporary fixing film. The temporary fixing of the semiconductor chip can be performed using, for example, a device such as a flip chip bonder or a die bonder. The layout and number of the semiconductor chips can be appropriately set depending on the shape and size of the temporary fixing film, the number of semiconductor package substrates to be produced, etc. For example, the semiconductor chips may be temporarily fixed by arranging them in a matrix shape of multiple rows and multiple columns.

<Step (C)>
Step (C) is a step of forming an encapsulating layer on the semiconductor chip. The encapsulating layer can be made of any material having insulating properties, and the above-mentioned photosensitive resin composition can be used. The encapsulating layer is usually formed by a method including a step of forming an encapsulating resin composition layer on the semiconductor chip and a step of thermally curing the resin composition layer to form the encapsulating layer.

The encapsulating resin composition layer is preferably formed by compression molding. In compression molding, the semiconductor chip and the encapsulating resin composition are typically placed in a mold, and pressure and, if necessary, heat are applied to the encapsulating resin composition in the mold to form an encapsulating resin composition layer that covers the semiconductor chip.

Specific operations of the compression molding method can be, for example, as follows. An upper mold and a lower mold are prepared as molds for compression molding. In addition, an encapsulating resin composition is applied to the semiconductor chip that has been temporarily fixed on the temporary fixing film as described above. The semiconductor chip to which the encapsulating resin composition has been applied is attached to the lower mold together with the substrate and the temporary fixing film. Thereafter, the upper mold and the lower mold are clamped together, and heat and pressure are applied to the encapsulating resin composition to perform compression molding.

Specific operations of the compression molding method may be, for example, as follows. An upper mold and a lower mold are prepared as molds for compression molding. An encapsulating resin composition is placed on the lower mold. A semiconductor chip is attached to the upper mold together with a substrate and a temporary fixing film. The upper and lower molds are then clamped together so that the encapsulating resin composition placed on the lower mold is in contact with the semiconductor chip attached to the upper mold, and heat and pressure are applied to perform compression molding.

The molding conditions vary depending on the composition of the encapsulating resin composition, and appropriate conditions can be adopted so that good encapsulation is achieved. For example, the temperature of the mold during molding is preferably a temperature at which the encapsulating resin composition can exhibit excellent compression moldability, and is preferably 80°C or higher, more preferably 100°C or higher, particularly preferably 120°C or higher, and preferably 200°C or lower, more preferably 170°C or lower, and particularly preferably 150°C or lower. The pressure applied during molding is preferably 1 MPa or higher, more preferably 3 MPa or higher, particularly preferably 5 MPa or higher, and preferably 50 MPa or lower, more preferably 30 MPa or lower, and particularly preferably 20 MPa or lower. The cure time is preferably 1 minute or higher, more preferably 2 minutes or higher, particularly preferably 5 minutes or higher, and preferably 60 minutes or lower, more preferably 30 minutes or lower, and particularly preferably 20 minutes or lower. Usually, the mold is removed after the encapsulating resin composition layer is formed. The mold may be removed before or after the encapsulating resin composition layer is thermally cured.

The compression molding method may be performed by discharging the encapsulating resin composition filled in a cartridge into a lower mold.

<Step (D)>
Step (D) is a step of peeling off the substrate and the temporary fixing film from the semiconductor chip. It is desirable to adopt an appropriate peeling method according to the material of the temporary fixing film. For example, the peeling method may include a method of heating, foaming or expanding the temporary fixing film to peel it off. In addition, for example, the peeling method may include a method of irradiating the temporary fixing film with ultraviolet light through the substrate to reduce the adhesive strength of the temporary fixing film to peel it off.

In the method of peeling off the temporary fixing film by heating, foaming or expanding it, the heating conditions are usually 100° C. to 250° C. for 1 second to 90 seconds or 5 minutes to 15 minutes. In the method of peeling off the temporary fixing film by reducing the adhesive strength of the temporary fixing film by irradiating it with ultraviolet light, the irradiation amount of ultraviolet light is usually 10 mJ/cm ² to 1000 mJ/cm ² .

<Step (E)>
Step (E) is a step of forming a rewiring formation layer as an insulating layer on the surface of the semiconductor chip from which the base material and the temporary fixing film are peeled off. The rewiring formation layer can be formed using the photosensitive resin composition according to this embodiment. The method for forming the rewiring formation layer can include forming a photosensitive resin composition layer in the same manner as in step (I) in the first example.

When forming the redistribution layer, via holes may be formed in the redistribution layer to provide interlayer connection between the semiconductor chip and the redistribution layer.

The via hole can be formed by carrying out an exposure process in which the surface of the photosensitive resin composition layer for forming the rewiring formation layer is irradiated with active light through a mask pattern, and a development process in which the non-exposed portion not irradiated with active light is developed and removed. The amount and duration of exposure of the active light can be appropriately set according to the photosensitive resin composition layer. Examples of the exposure method include a contact exposure method in which a mask pattern is brought into close contact with the photosensitive resin composition layer and exposed, and a non-contact exposure method in which a mask pattern is not brought into close contact with the photosensitive resin composition layer and exposed using parallel light. The exposure and development methods can be carried out as described in the first example.

The shape of the via hole is not particularly limited, but is generally circular (approximately circular). The top diameter of the via hole is preferably 50 μm or less, more preferably 30 μm or less, and even more preferably 20 μm or less, and is preferably 0.1 μm or more, preferably 0.5 μm or more, and more preferably 1.0 μm or more. Here, the top diameter of the via hole refers to the diameter of the opening of the via hole on the surface of the rewiring formation layer.

After forming the photosensitive resin composition layer and forming via holes as necessary, a thermal curing step may be carried out. The thermal curing method may be as described in the first example.

<Step (F)>
Step (F) is a step of forming a redistribution layer as a conductor layer on the redistribution formation layer. The method of forming the redistribution layer on the redistribution formation layer can be the same as the method of forming a conductor layer on the insulating layer in the first example. In addition, steps (E) and (F) may be repeated to alternately stack the redistribution layer and the redistribution formation layer (build up).

<Step (G)>
Step (G) is a step of forming a solder resist layer on the rewiring layer. The material of the solder resist layer can be any material having insulating properties. Among them, photosensitive resins and thermosetting resins are preferred from the viewpoint of ease of manufacturing the semiconductor package substrate. The photosensitive resin composition according to this embodiment may also be used.

In step (G), bumping processing may be performed to form bumps, if necessary. The bumping processing may be performed using a solder ball, solder plating, or the like. In addition, the formation of via holes in the bumping processing may be performed in the same manner as in step (E).

The method for manufacturing a semiconductor package substrate may include step (H) in addition to steps (A) to (G). Step (H) is a step of dicing a plurality of semiconductor package substrates into individual semiconductor package substrates to separate them. There are no particular limitations on the method for dicing the semiconductor package substrates into individual semiconductor package substrates.

[Semiconductor device]
A semiconductor device according to an embodiment of the present invention includes the above-mentioned semiconductor package substrate. Examples of the semiconductor device on which the semiconductor package substrate is mounted include various semiconductor devices used in electrical products (e.g., computers, mobile phones, smartphones, tablet devices, wearable devices, digital cameras, medical devices, televisions, etc.) and vehicles (e.g., motorcycles, automobiles, trains, ships, aircraft, etc.).

The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples. In the following description, the terms "parts" and "%" used to indicate amounts refer to "parts by mass" and "% by mass", respectively, unless otherwise specified. Furthermore, the operations described below were carried out in the atmosphere at room temperature and normal pressure (25°C and 1 atm) unless otherwise specified.

[Synthesis Example 1: Synthesis of (A) Polymer A-1]

29.4 g of 3,3',4,4'-biphenyltetracarboxylic dianhydride (sBPDA) was placed in a 2 L separable flask, 500 mL of N-methyl-2-pyrrolidone was added, and the mixture was stirred at room temperature. 45.0 g of 5-(4-aminophenoxy)-3-[4-(4-aminophenoxy)phenyl]-1,1,3-trimethylindan (INDAN) was then added. At the same time, the reaction vessel was heated in an oil bath until the internal temperature reached 40°C, and polymerization was carried out for 20 hours.

Next, 1.12 g of potassium hydroxide was added to the reaction solution and stirred at room temperature, then 8.8 g of ethylene carbonate was added, and at the same time, the reaction vessel was heated in an oil bath until the internal temperature reached 80°C, and stirred for 10 hours. The resulting reaction solution was adjusted to 40°C, and 18.1 g of acrylic acid chloride, 0.5 g of dimethylaminopyridine, and 20 g of triethylamine were added, and stirred for 3 hours.

Next, the resulting reaction solution was dropped into 6 L of ultrapure water to precipitate the polymer, which was then purified. The purified polymer was separated by filtration and dried under heating at 80° C. in a vacuum dryer to obtain 71 g of Polymer A-1.
The molecular weight of Polymer A-1 was measured by gel permeation chromatography (standard polystyrene equivalent) and found to have a weight average molecular weight (Mw) of 50,000.

[Synthesis Example 2: Synthesis of (A) Polymer A-2]

29.4 g of 3,3',4,4'-biphenyltetracarboxylic dianhydride (sBPDA) was placed in a 2 L separable flask, 500 mL of N-methyl-2-pyrrolidone was added, and the mixture was stirred at room temperature. 45.0 g of 5-(4-aminophenoxy)-3-[4-(4-aminophenoxy)phenyl]-1,1,3-trimethylindan (INDAN) was then added. At the same time, the reaction vessel was heated in an oil bath until the internal temperature reached 40°C, and polymerization was carried out for 20 hours.

Next, 1.12 g of potassium hydroxide was added to the reaction solution and stirred at room temperature, then 8.8 g of ethylene carbonate was added, and at the same time, the reaction vessel was heated in an oil bath until the internal temperature reached 80°C, and stirred for 10 hours. The resulting reaction solution was adjusted to 40°C, and 20.6 g of methacrylic acid chloride, 0.5 g of dimethylaminopyridine, and 20 g of triethylamine were added, and stirred for 3 hours.

Next, the obtained reaction solution was dropped into 6 L of ultrapure water to precipitate the polymer, which was then purified. The purified polymer was separated by filtration and dried under heating at 80° C. in a vacuum dryer to obtain 70 g of Polymer A-2.
The molecular weight of Polymer A-2 was measured by gel permeation chromatography (standard polystyrene equivalent) and found to have a weight average molecular weight (Mw) of 52,000.

[Synthesis Example 3: Synthesis of (A) Polymer A-3]

51.8 g of 2,2-bis[4-(3,4-dicarboxyphenoxy)phenyl]propane dianhydride (BPADA) was placed in a 2 L separable flask, 500 mL of N-methyl-2-pyrrolidone was added, and the mixture was stirred at room temperature. 45.0 g of 5-(4-aminophenoxy)-3-[4-(4-aminophenoxy)phenyl]-1,1,3-trimethylindan (INDAN) was then added. At the same time, the reaction vessel was heated in an oil bath until the internal temperature reached 40°C, and polymerization was carried out for 20 hours.

Next, 1.12 g of potassium hydroxide was added to the reaction solution and stirred at room temperature, then 8.8 g of ethylene carbonate was added, and at the same time, the reaction vessel was heated in an oil bath until the internal temperature reached 80°C, and stirred for 10 hours. The resulting reaction solution was adjusted to 40°C, and 18.1 g of acrylic acid chloride, 0.5 g of dimethylaminopyridine, and 20 g of triethylamine were added, and stirred for 3 hours.

Next, the obtained reaction solution was dropped into 6 L of ultrapure water to precipitate the polymer, which was then purified. The purified polymer was separated by filtration and then dried under heating at 80° C. in a vacuum dryer to obtain 90 g of Polymer A-3.
The molecular weight of Polymer A-3 was measured by gel permeation chromatography (standard polystyrene equivalent) and found to have a weight average molecular weight (Mw) of 40,000.

[Synthesis Example 4: (A) Synthesis of Polymer A-4]

51.8 g of 2,2-bis[4-(3,4-dicarboxyphenoxy)phenyl]propane dianhydride (BPADA) was placed in a 2 L separable flask, 500 mL of N-methyl-2-pyrrolidone was added, and the mixture was stirred at room temperature. 45.0 g of 5-(4-aminophenoxy)-3-[4-(4-aminophenoxy)phenyl]-1,1,3-trimethylindan (INDAN) was then added. At the same time, the reaction vessel was heated in an oil bath until the internal temperature reached 40°C, and polymerization was carried out for 20 hours.

Next, 1.12 g of potassium hydroxide was added to the reaction solution and stirred at room temperature, then 8.8 g of ethylene carbonate was added, and at the same time, the reaction vessel was heated in an oil bath until the internal temperature reached 80°C, and stirred for 10 hours. The resulting reaction solution was adjusted to 40°C, and 20.6 g of methacrylic acid chloride, 0.5 g of dimethylaminopyridine, and 20 g of triethylamine were added, and stirred for 3 hours.

Next, the resulting reaction solution was dropped into 6 L of ultrapure water to precipitate the polymer, which was then purified. The purified polymer was separated by filtration and dried under heating at 80° C. in a vacuum dryer to obtain 92 g of Polymer A-4.
The molecular weight of Polymer A-4 was measured by gel permeation chromatography (standard polystyrene equivalent) to find that the weight average molecular weight (Mw) was 42,000.

[Examples and Comparative Examples]
The reagents shown in Tables 1 and 2 below were mixed in the amounts (parts by mass) shown in each table to prepare varnish-like photosensitive resin compositions using a high-speed rotating mixer. Solutions (non-volatile content 30%) of the polymers A-1 to A-4 obtained in Synthesis Examples 1 to 4 above were prepared, respectively, and these solutions were used for mixing.
Details of each reagent are as follows.

<Component (A): Polyimide Precursor>
Synthesis Example 1: Solution of polymer A-1 produced in Synthesis Example 1 (non-volatile content: 30%).
Synthesis Example 2: Solution of polymer A-2 produced in Synthesis Example 2 (non-volatile content: 30%).
Synthesis Example 3: Solution of polymer A-3 produced in Synthesis Example 3 (non-volatile content: 30%).
Synthesis Example 4: Solution of polymer A-4 produced in Synthesis Example 4 (non-volatile content: 30%).

<Component (B): Crosslinking Agent>
TMPT: trimethylolpropane trimethacrylate (trifunctional methacrylate, manufactured by Shin-Nakamura Chemical Co., Ltd.).
A-TMPT: trimethylolpropane triacrylate (trifunctional acrylate, manufactured by Shin-Nakamura Chemical Co., Ltd.).
SR209: Tetraethylene glycol dimethacrylate (bifunctional methacrylate, manufactured by Tomoe Engineering Co., Ltd.).

<Component (C): Photoradical generator>
Omnirad 819: A compound represented by the following structure (manufactured by IGM, molecular weight 418.5, Bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide)

Omnirad 379EG: a compound represented by the following structure (manufactured by IGM, molecular weight 380.5, 2-dimethylamino-2-(4-methyl-benzyl)-1-(4-morpholin-4-yl-phenyl)-butan-1-one, CAS 119344-86-4)

Irgacure OXE-01: A compound represented by the following structure (manufactured by BASF, molecular weight 445.6, 1,2-Octanedione, 1-[4-(phenylthio) phenyl]-, 2-(o-benzoyloxime))

Irgacure OXE-02: A compound represented by the following structure (manufactured by BASF, molecular weight 412.5, ethane, 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]-, 1-(o-acetyloxime))

Omnipol TP: a compound represented by the following structure (manufactured by IGM, molecular weight is 900 or more), in the formula, a, b, and c each represent an integer of 1 to 10.

Omnipol 910: a compound represented by the following structure (manufactured by IGM, molecular weight is 850 or more), in the formula, d represents an integer of 1 to 10.

<Component (D): High Molecular Weight Sensitizer>
Omnipol ASA: manufactured by IGM, molecular weight approximately 510, Poly(ethylene glycol) bis(p-dimethylaminobenzoate), in which r1 represents 3 or 4.

Esacure A 198: manufactured by IGM, molecular weight 413.5, benzoic acid, 4-(dimethylamino)-, 1,1'-[(methylamino)di-2,1-ethanediyl] ester

<Component (E): Low-Molecular-Weight Photosensitizer>
Omnirad EDB: manufactured by IGM, molecular weight 193, Ethyl-4-(dimethylamino)-benzoate

EAB: (Tokyo Chemical Industry Co., Ltd., molecular weight 343, 4,4'-Bis(diethylamino)benzophenone)

[Production of photosensitive film]
A PET film (Toray Industries, Inc., "Lumirror T6AM", thickness 38 μm) was prepared as a support. The photosensitive resin composition prepared in each Example and Comparative Example was uniformly applied to the support using a die coater so that the thickness of the photosensitive resin composition layer after drying was 30 μm, and the support was dried at 80° C. to 120° C. for 6 minutes to form a photosensitive resin composition layer. Next, a cover film (biaxially oriented polypropylene film, Oji F-Tex Co., Ltd., "MA-411") was placed on the surface of the photosensitive resin composition layer and laminated at 80° C. to produce a photosensitive film having a three-layer structure of support/photosensitive resin composition layer/cover film.

[Evaluation of Resolution]
A copper layer having a thickness of 5 μm was formed on a silicon wafer by plating, and roughened with a 1% aqueous hydrochloric acid solution for 60 seconds to obtain a substrate. The cover film was peeled off from the photosensitive film. The photosensitive film was placed on the substrate so that the photosensitive resin composition layer was in contact with the surface of the copper layer. The substrate and the photosensitive film were laminated using a vacuum laminator ("VP160" manufactured by Nikko Materials Co., Ltd.) to obtain a laminate having a layer structure of substrate/photosensitive resin composition layer/support. The pressure bonding conditions in the lamination were a vacuum drawing time of 30 seconds, a pressure bonding temperature of 60° C., a pressure bonding pressure of 0.7 MPa, and a pressure bonding time of 30 seconds. The laminate was left to stand at room temperature for 30 minutes, and then the support was peeled off from the laminate.

The photosensitive resin composition layer of the laminate was exposed to ultraviolet light (wavelength 365 nm, intensity 40 mW/cm ² ). The exposure dose was set to an optimal value in the range of 100 mJ/cm ² to 1000 mJ/cm ² . For the exposure pattern, a quartz glass mask was used to draw round holes (via holes) with opening diameters of 20 μm, 30 μm, 40 μm, 50 μm, 60 μm, 70 μm, 80 μm, 90 μm, and 100 μm. Thereafter, the laminate was left to stand at room temperature for 5 minutes, and then heat-treated at 100° C. for 3 minutes.

The entire surface of the photosensitive resin composition layer on the laminate was spray-developed using cyclopentanone at 23°C as a developer at a spray pressure of 0.1 MPa for an optimal time of 30 to 100 seconds. Next, propylene glycol monomethyl ether acetate was spray-rinsed at a spray pressure of 0.1 MPa for 30 seconds. The photosensitive resin composition layer was then cured by heating at 170°C for 180 minutes to obtain a cured layer.

In the cured layer, a via hole was formed in the portion where a round hole (via hole) was drawn by exposure. The diameter of the bottom of this via hole was observed with a scanning electron microscope (SEM) (magnification 1000 times). The smallest size via hole that could be opened without residue or peeling was determined as the limiting opening via. Based on the opening diameter of the limiting opening via, the resolution was evaluated according to the following evaluation criteria. The smaller the opening diameter of the limiting opening via, the better the resolution of the photosensitive resin composition.

(Evaluation Criteria for Resolution)
"Good": The opening diameter of the marginal opening via is 30 μm or less.
"△": The opening diameter of the limit opening via is 40 μm or more and 50 μm or less.
"X": There is no critical opening via with an opening diameter of 50 μm or less.

[Evaluation of cross-sectional shape (undercut)]
The limiting open via of the cured layer was observed with a SEM (magnification 2000 times). The radius (μm) of the top and bottom of the cross section of the limiting open via was measured with the SEM. The difference between the radius of the bottom and the radius of the top (radius of the bottom - radius of the top) was calculated, and the calculated value was taken as the undercut. This undercut was evaluated according to the following evaluation criteria. The closer to zero the undercut, the better.

(Evaluation Criteria for Undercut)
"◎": No undercut.
"Good": Undercut is less than 2 μm.
"△": Undercut is 2 μm or more and 4 μm or less.
"X": The undercut is greater than 4 μm, or a via hole with an opening diameter of 50 μm is not opened.

[Evaluation of film remaining property]
The limiting open via of the cured layer was observed by SEM (magnification 2000 times). The thickness T1 (μm) of the cured layer at the end of the limiting open via was measured by SEM, and the remaining film ratio was calculated by comparing it with the thickness T0 (μm) of the photosensitive resin composition layer before exposure after drying. The remaining film ratio (%) was calculated by "thickness T1 of the cured layer at the end of the limiting open via ÷ thickness T0 of the photosensitive resin composition layer before exposure × 100". Based on the obtained remaining film ratio, the remaining film property was evaluated according to the following evaluation criteria. The higher the remaining film ratio, the better the remaining film property.

(Evaluation Criteria for Film Retention)
"Good": Residual film rate is 70% or more.
"△": Residual film rate is less than 70% and is 50% or more.
"X": Residual film rate is less than 50%.
[result]
The results of the Examples and Comparative Examples are shown in Tables 1 and 2 below.

Claims (13)

(A) a polyimide precursor;
(B) a crosslinking agent,
A photosensitive resin composition comprising: (C) a photoradical generator; and (D) a photosensitizer having a molecular weight of 400 or more. The photosensitive resin composition according to claim 1, wherein component (A) contains an indane skeleton. The photosensitive resin composition according to claim 1, wherein component (A) contains a radical reactive group. The photosensitive resin composition according to claim 1, wherein the component (A) contains a structural unit represented by the following formula (A-1):

(In formula (A-1),
Each A ^a independently represents a tetravalent organic group.
Each B ^a independently represents a divalent organic group.
R ^1a and R ^2a each independently represent a hydrogen atom or a monovalent organic group;
n _a represents an integer of 5 or more and 200 or less. The photosensitive resin composition according to claim 1, wherein component (A) has a weight average molecular weight of 5,000 or more and 1,000,000 or less. The photosensitive resin composition according to claim 1, wherein component (B) contains an ethylenically unsaturated bond. The photosensitive resin composition according to claim 1, wherein component (C) includes (C-1) a photoradical generator having a molecular weight of 450 or more. The photosensitive resin composition according to claim 1, wherein component (D) contains a tertiary amino group in the molecule. The photosensitive resin composition according to claim 1, wherein component (D) contains an aminobenzoyl group in the molecule. A support and a photosensitive resin composition layer formed on the support,
A photosensitive film, wherein the photosensitive resin composition layer comprises the photosensitive resin composition according to any one of claims 1 to 9. A semiconductor package substrate having an insulating layer formed from a cured product of the photosensitive resin composition according to any one of claims 1 to 9. A semiconductor device comprising the semiconductor package substrate according to claim 11. A step of forming a photosensitive resin composition layer containing the photosensitive resin composition according to any one of claims 1 to 9 on a circuit board;
A step of irradiating the photosensitive resin composition layer with actinic rays;
developing the photosensitive resin composition layer;
A method for manufacturing a semiconductor package substrate, comprising: