JP7530736B2 - Photosensitive resin composition, method for producing cured relief pattern, cured relief pattern, semiconductor device, and display device - Google Patents

Description

The present invention relates to a photosensitive resin composition, a method for producing a cured relief pattern obtained by curing the photosensitive resin composition, the cured relief pattern, and a semiconductor device and a display device having the cured relief pattern.

Conventionally, polyimide resins, which have excellent heat resistance, electrical properties, and mechanical properties, have been used as insulating materials for electronic components, and passivation films, surface protective films, and interlayer insulating films for semiconductor devices. Among these polyimide resins, those provided in the form of photosensitive polyimide precursors can easily form heat-resistant relief pattern coatings by applying the precursor, exposing it to light, developing it, and subjecting it to a thermal imidization treatment by curing. Such photosensitive polyimide precursors have the characteristic of enabling significant process shortening compared to conventional non-photosensitive polyimides.

Meanwhile, in recent years, the methods of mounting semiconductor devices on printed wiring boards have also changed in order to improve integration and functionality, as well as to reduce chip size. Conventional mounting methods using metal pins and lead-tin eutectic solder have been replaced by structures in which a polyimide coating is in direct contact with solder bumps, such as BGA (ball gripped array) and CSP (chip size packaging), which allow for higher density mounting. When forming such bump structures, the coating is required to have high heat resistance and chemical resistance.

Furthermore, as semiconductor devices become more miniaturized, the problem of wiring delay becomes apparent. As a means of improving the wiring resistance of semiconductor devices, the gold or aluminum wiring that has been used so far is being replaced by copper or copper alloy wiring, which has lower resistance.
Also, a method of preventing wiring delay by increasing the insulation between wirings has been adopted. In recent years, semiconductor devices are often made of low-dielectric constant materials as highly insulating materials. However, low-dielectric constant materials tend to be brittle and easily broken. In semiconductor devices made of low-dielectric constant materials, there is a problem that when the semiconductor chip is mounted on a substrate after a solder reflow process, for example, the low-dielectric constant material portion is broken due to contraction caused by temperature change.

As a means of solving this problem, for example, Patent Document 1 discloses the use of a photosensitive polyimide precursor in which a portion of the photosensitive group having a terminal ethylene bond and 4 or more carbon atoms is replaced with a hydrocarbon group having 1 to 3 carbon atoms.

In addition, in order to achieve high film strength, a photosensitive polyimide with a biphenyl skeleton in the diamine unit has been reported. According to Patent Document 2, by using a polymer composed of a biphenyl skeleton containing halogen atoms, a photopolymerization initiator with a specific molecular skeleton, and a silicon coupler, a polyimide pattern with high i-line transmittance and low residual stress can be obtained while maintaining high heat resistance and good mechanical properties.

Japanese Patent Application Publication No. 6-80776 Patent No. 6146005

However, the photosensitive resin compositions comprising polyimide precursors described in Patent Documents 1 and 2 are still insufficient in terms of Young's modulus, which is an index of film strength.
In order to further improve the membrane strength, it is common to use a polymer with an increased amount of highly linear and rigid aromatic components. However, according to common technical knowledge, this approach has the problem of decreasing the breaking elongation of the membrane.

The present invention therefore aims to provide a photosensitive resin composition that can achieve both high film strength and breaking elongation after the coating film is cured, and can stably open a via pattern, a method for producing a cured relief pattern using the photosensitive resin composition, a cured relief pattern, and a semiconductor device and a display device that include the cured relief pattern.

｛式（１）中、Ｘ_１は炭素数６～４０の４価の有機基であり、Ｒ_１及びＲ_２は、それぞれ独立に、水素原子又は下記一般式（２）：

（式中、Ｒ_３は、水素原子又は炭素数１～３の有機基であり、Ｒ_４及びＲ_５は、それぞれ独立に、水素原子又は炭素数１～３の有機基であり、そしてｍは、２～１０の整数である。）で表される一価の有機基、又は炭素数１～４の飽和脂肪族基であり（但し、Ｒ_１及びＲ_２の両者は同時に水素原子であることはない。）、
Ｙ_１は、下記一般式（３）：

（式中、Ｒ_６～Ｒ_１３は、各々独立に、水素原子、フッ素原子または１価の有機基である。）で表される炭素数６～４０の２価の有機基である。｝
で表される前駆体を含み、
前記（Ｄ）溶剤は、γ－ブチロラクトン、ジメチルスルホキシド、３－メトキシ－Ｎ，Ｎ－ジメチルプロピオンアミドの少なくとも１種から選択され、
以下の数式（Ｓ１）：
現像時間増加率（％）＝（ＤＴ_４８／ＤＴ_２）×１００ （Ｓ１）
（式中、ＤＴ_２およびＤＴ_４８は当該感光性樹脂組成物をシリコンウェハー上に塗膜し、１１０℃２４０秒間ベーク処理を行った後に、２時間および４８時間静置し、２３℃で現像液としてシクロペンタノンを用いて完全に溶解するまでの時間を示す。なお、塗膜工程では、ベーク処理後の膜厚が１０．５μｍであるものとする。）
で表される現像時間増加率が１３０％以上２００％未満であることを特徴とする感光性樹脂組成物。
［２］
前記（Ａ）ポリイミド前駆体の一般式（１）におけるＹ_１が、下記一般式（４）：

｛式（４）中、Ｒ_１４及びＲ_１５は、各々独立に、水素原子又は炭化水素から成る１価の有機基である。｝の構造を有する、［１］に記載の感光性樹脂組成物。
［３］
前記（Ａ）ポリイミド前駆体において、前記一般式（１）中の前記Ｘ_１が、ビフェニルテトラカルボン酸二無水物（ＢＰＤＡ）、ピロメリット酸二無水物（ＰＭＤＡ）から選択される少なくとも１種に由来する４価の有機基である、［１］又は［２］に記載の感光性樹脂組成物。
［４］
前記現像時間増加率が１３５％以上１６０％未満である、［１］～［３］のいずれかに記載の感光性樹脂組成物。
［５］
前記（Ａ）ポリイミド前駆体を少なくとも２種以上含有する、［１］～［４］のいずれかに記載の感光性樹脂組成物。
［６］
前記感光性樹脂組成物中に含まれる全固形分のうち、（Ａ）ポリイミド前駆体を除く成分量の合計が、（Ａ）ポリイミド前駆体に対して２６％以上６０％未満である、［１］～［５］のいずれかに記載の感光性樹脂組成物。
［７］
以下の工程：
（１）［１］～［６］のいずれかに記載の感光性樹脂組成物を基板上に塗布して、感光性樹脂層を該基板上に形成する工程、
（２）該感光性樹脂層を露光する工程、
（３）該露光後の感光性樹脂層を現像して、レリーフパターンを形成する工程、及び
（４）該レリーフパターンを加熱処理して、硬化レリーフパターンを形成する工程、
を含む、硬化レリーフパターンの製造方法。
［８］
以下の工程：
（１）［１］～［６］のいずれかに記載の感光性樹脂組成物を基板上に塗布して、
感光性樹脂層を該基板上に形成する工程、
（２）該感光性樹脂層を露光する工程、
（３）該露光後の感光性樹脂層を現像して、レリーフパターンを形成する工程、及び
（４）該レリーフパターンを加熱処理して、硬化レリーフパターンを形成する工程、を含む硬化レリーフパターンの製造方法であって、
（１）塗布による感光性樹脂層形成時に１１０℃２４０秒間の加熱を行う、硬化レリーフパターンの製造方法。
［９］
［７］又は［８］に記載の方法により製造された硬化レリーフパターン。
［１０］
半導体素子と、該半導体素子の上部に設けられた硬化膜とを備える半導体装置であって、該硬化膜は、［９］に記載の硬化レリーフパターンである、半導体装置。
［１１］
表示体素子と、該表示体素子の上部に設けられた硬化膜とを備える表示体装置であって、該硬化膜は、［９］に記載の硬化レリーフパターンである、表示体装置。 In view of the problems of the above-mentioned conventional techniques, the present inventors conducted extensive research and experiments, and discovered that a photosensitive resin composition in which a photosensitive resin having a biphenyl skeleton is dissolved in a specific solvent changes its solubility in a developer due to a change in the resin conformation inside the coating film over time after the coating film is formed, and that a cured relief pattern having unprecedentedly excellent film strength, high elongation, and patterning properties can be obtained. That is, the present invention is as follows.
[1]
Ingredients below:
(A) a polyimide precursor;
(B) a photopolymerization initiator,
A photosensitive resin composition comprising (C) a photopolymerizable substance and (D) a solvent, wherein the (A) polyimide precursor is represented by the following general formula (1):

In formula (1), _X1 is a tetravalent organic group having 6 to 40 carbon atoms, and _R1 and _R2 each independently represent a hydrogen atom or a group represented by the following general formula (2):

(wherein _R3 is a hydrogen atom or an organic group having 1 to 3 carbon atoms, _R4 and _R5 are each independently a hydrogen atom or an organic group having 1 to 3 carbon atoms, and m is an integer from 2 to 10), or a saturated aliphatic group having 1 to 4 carbon atoms (with the proviso that _R1 and _R2 cannot both be hydrogen atoms at the same time),
Y ₁ is represented by the following general formula (3):

(wherein R ₆ to R ₁₃ are each independently a hydrogen atom, a fluorine atom, or a monovalent organic group) and is a divalent organic group having 6 to 40 carbon atoms.)
The precursor is represented by
The (D) solvent is selected from at least one of γ-butyrolactone, dimethylsulfoxide, and 3-methoxy-N,N-dimethylpropionamide;
The following formula (S1):
Development time increase rate (%) = ( _DT48 / _DT2 ) x 100 (S1)
(In the formula, DT ₂ and DT ₄₈ represent the time taken for the photosensitive resin composition to be completely dissolved in cyclopentanone as a developer at 23° C. after coating the composition on a silicon wafer and baking at 110° C. for 240 seconds, followed by leaving the composition to stand for 2 hours and 48 hours. Note that in the coating process, the film thickness after baking is 10.5 μm.)
The photosensitive resin composition according to claim 1, wherein the development time increase rate represented by the following formula is 130% or more and less than 200%.
[2]
The polyimide precursor (A) is _represented by the following general formula (4):

The photosensitive resin composition according to [1], having a structure of {in formula (4), R ₁₄ and R ₁₅ each independently represent a hydrogen atom or a monovalent organic group composed of a hydrocarbon.}.
[3]
The photosensitive resin composition according to [1] or [2], wherein in the polyimide precursor (A), the _X1 in the general formula (1) is a tetravalent organic group derived from at least one selected from biphenyltetracarboxylic dianhydride (BPDA) and pyromellitic dianhydride (PMDA).
[4]
The photosensitive resin composition according to any one of [1] to [3], wherein the development time increase rate is 135% or more and less than 160%.
[5]
The photosensitive resin composition according to any one of [1] to [4], comprising at least two kinds of the polyimide precursor (A).
[6]
The photosensitive resin composition according to any one of [1] to [5], wherein a total amount of components excluding the polyimide precursor (A) in a total solid content contained in the photosensitive resin composition is 26% or more and less than 60% relative to the polyimide precursor (A).
[7]
The following steps:
(1) A step of applying the photosensitive resin composition according to any one of items [1] to [6] onto a substrate to form a photosensitive resin layer on the substrate;
(2) a step of exposing the photosensitive resin layer to light;
(3) developing the exposed photosensitive resin layer to form a relief pattern; and (4) heat-treating the relief pattern to form a cured relief pattern.
2. A method for producing a cured relief pattern comprising:
[8]
The following steps:
(1) A photosensitive resin composition according to any one of items [1] to [6] is applied onto a substrate,
forming a photosensitive resin layer on the substrate;
(2) a step of exposing the photosensitive resin layer to light;
(3) developing the exposed photosensitive resin layer to form a relief pattern; and (4) heat-treating the relief pattern to form a cured relief pattern,
(1) A method for producing a cured relief pattern, in which heating is performed at 110° C. for 240 seconds when a photosensitive resin layer is formed by coating.
[9]
A cured relief pattern produced by the method according to [7] or [8].
[10]
A semiconductor device comprising a semiconductor element and a cured film provided on an upper portion of the semiconductor element, the cured film having the cured relief pattern according to [9].
[11]
A display device comprising a display element and a cured film provided on the upper portion of the display element, the cured film being the cured relief pattern according to [9].

The present invention provides a photosensitive resin composition that combines high film strength and high elongation and can stably produce a cured relief pattern, a method for producing a cured relief pattern using the photosensitive composition, a cured relief pattern, and a semiconductor device and a display device having the cured relief pattern.

The following provides a detailed explanation of the form for carrying out the present invention (hereinafter, abbreviated as "embodiment"). Note that the present invention is not limited to the following embodiment, and can be modified in various ways within the scope of the gist of the invention.

｛式（１）中、Ｘ_１は炭素数６～４０の４価の有機基であり、Ｒ_１及びＲ_２は、それぞれ独立に、水素原子又は下記一般式（２）：

（式中、Ｒ_３は、水素原子又は炭素数１～３の有機基であり、Ｒ_４及びＲ_５は、それぞれ独立に、水素原子又は炭素数１～３の有機基であり、そしてｍは、２～１０の整数である。）で表される一価の有機基、又は炭素数１～４の飽和脂肪族基であり（但し、Ｒ_１及びＲ_２の両者は同時に水素原子であることはない。）、
Ｙ_１は、下記一般式（３）：

で表される炭素数６～４０の２価の有機基であり、Ｒ_６～Ｒ_１３は、各々独立に、水素原子、フッ素原子または１価の有機基である。｝
で表される前駆体を含み、
（Ｄ）溶剤は、γ－ブチロラクトン、ジメチルスルホキシド、３－メトキシ－Ｎ，Ｎ－ジメチルプロピオンアミドの少なくとも１種から選択される。
そして、本発明の感光性樹脂組成物は、下記数式（Ｓ１）：
現像時間増加率（％）＝（ＤＴ_４８／ＤＴ_２）×１００ （Ｓ１）
（式中、ＤＴ_２およびＤＴ_４８は、当該感光性樹脂組成物をシリコンウェハー上に塗膜し、１１０℃２４０秒間ベーク処理を行った後に、２時間および４８時間静置し、２３℃で現像液としてシクロペンタノンを用いて完全に溶解するまでの時間を示す。なお、塗膜工程では、ベーク処理後の膜厚が１０．５μｍであるものとする。）
で表される現像時間増加率が、１３０％以上２００％未満であることを特徴とする。 In the present embodiment, the photosensitive resin composition is a negative type photosensitive resin composition including (A) a polyimide precursor, (B) a photopolymerization initiator, (C) a photopolymerizable substance, and (D) a solvent, and the (A) polyimide precursor is represented by the following general formula (1):

In formula (1), _X1 is a tetravalent organic group having 6 to 40 carbon atoms, and _R1 and _R2 each independently represent a hydrogen atom or a group represented by the following general formula (2):

(wherein _R3 is a hydrogen atom or an organic group having 1 to 3 carbon atoms, _R4 and _R5 are each independently a hydrogen atom or an organic group having 1 to 3 carbon atoms, and m is an integer from 2 to 10), or a saturated aliphatic group having 1 to 4 carbon atoms (with the proviso that _R1 and _R2 cannot both be hydrogen atoms at the same time),
Y ₁ is represented by the following general formula (3):

and R ₆ to R ₁₃ are each independently a hydrogen atom, a fluorine atom, or a monovalent organic group.}
The precursor is represented by
The solvent (D) is selected from at least one of γ-butyrolactone, dimethylsulfoxide, and 3-methoxy-N,N-dimethylpropionamide.
The photosensitive resin composition of the present invention has the following formula (S1):
Development time increase rate (%) = ( _DT48 / _DT2 ) x 100 (S1)
(In the formula, DT ₂ and DT ₄₈ represent the time taken for the photosensitive resin composition to be completely dissolved in cyclopentanone as a developer at 23° C. after coating the composition on a silicon wafer and baking at 110° C. for 240 seconds, followed by leaving the composition to stand for 2 hours and 48 hours. Note that in the coating process, the film thickness after baking is 10.5 μm.)
The developing time increase rate represented by the formula (1) is 130% or more and less than 200%.

In this way, the photosensitive resin composition of the present invention, in which a photosensitive resin having a biphenyl skeleton is dissolved in a specific solvent, changes the resin conformation inside the coating film over time after coating film formation, thereby changing the solubility in a developer, and can provide a cured relief pattern that has unprecedentedly excellent film strength, high elongation, and patterning properties.
Therefore, the photosensitive resin composition of the present invention can achieve both high film strength and high breaking elongation after the coating film is cured, making it possible to stably open a via pattern.

Although the detailed mechanism by which the above-mentioned effects are achieved is not clear, the mechanism presumed by the present inventors will be described below.
A photosensitive resin composition containing a solvent behaves as a viscous fluid, but when the composition is coated and baked, most of the solvent evaporates, forming a thin film that does not appear to be fluid. However, since the film contains residual solvent and low molecular weight additive components, strictly speaking, the molecular mobility of the polymer is not completely suppressed, and the polymers are repeatedly rearranged to build a stable three-dimensional structure by intermolecular interaction forces. If a rigid polymer is used to improve the film strength, strong interaction forces such as π-π stacking and intermolecular CT transition due to aromatic parts act between the polymers in the film, and it is thought that they pack together over a long period of time, causing a decrease in solubility in the developer. A photosensitive resin composition in which packing occurs due to baking and changes over time after coating, and the development time increases, can become a pattern film with unprecedented strength when a final cured relief pattern is formed.

In addition, the solvent used is selective. In most of the reported examples of photosensitive resin compositions for interlayer insulating films, which are often used in semiconductor packages, N-methylpyrrolidone was used as the solvent. This N-methylpyrrolidone solvent has the characteristic of being very soluble in polymers or additives, and has been used preferably as a stable solvent for resin compositions with little concern about aggregation and precipitation. However, this means that N-methylpyrrolidone is more likely to solvate polymers and additives than other solvents. When comparing a polymer state stabilized by solvation with a large number of solvent molecules with a state stabilized by intermolecular interactions between single polymer molecules, the former is preferred from the perspective of thermodynamic entropy. Therefore, when N-methylpyrrolidone is used, the aforementioned increase in development time does not occur, and it was discovered that it occurs specifically only when using certain solvents, such as γ-butyrolactone and dimethyl sulfoxide, which have poorer solubility than N-methylpyrrolidone.

According to reports made so far, it has generally been believed that the time required for development does not change depending on the time between the formation of the coating film and development, but this is to ensure robustness in the manufacturing process, and no inventions have been made so far that have been inspired by this point in order to achieve even greater film strength and elongation.

The photosensitive resin composition of this embodiment may contain other components as desired. Each component is described below in order.

In addition, throughout this specification, when multiple structures represented by the same symbol in a general formula are present in a molecule, they may be the same or different.

｛式中、Ｘ_１は、４価の有機基であり、Ｙ_１は、２価の有機基であり、ｎは、２～１５０の整数であり、Ｒ_１及びＲ_２は、それぞれ独立に、水素原子又は下記一般式（２）：

（式中、Ｒ_３は、水素原子又は炭素数１～３の有機基であり、Ｒ_４及びＲ_５は、それぞれ独立に、水素原子又は炭素数１～３の有機基であり、そしてｍは、２～１０の整数である。）で表される一価の有機基、又は炭素数１～４の飽和脂肪族基である。但し、Ｒ_１及びＲ_２の両者は同時に水素原子であることはない。｝ (A) Polyimide precursor The (A) polyimide precursor used in the present invention will be described. The resin component in the photosensitive resin composition of the present invention is a polyamide having a structural unit represented by the following general formula (1). (A) Polyimide precursor is converted to polyimide by heating (e.g., 200°C or higher) for cyclization treatment.
The following general formula (1):

In the formula, _X1 is a tetravalent organic group, _Y1 is a divalent organic group, n is an integer of 2 to 150, and _R1 and _R2 each independently represent a hydrogen atom or a group represented by the following general formula (2):

(wherein R ₃ is a hydrogen atom or an organic group having 1 to 3 carbon atoms, R ₄ and R ₅ are each independently a hydrogen atom or an organic group having 1 to 3 carbon atoms, and m is an integer from 2 to 10), or a saturated aliphatic group having 1 to 4 carbon atoms. However, R ₁ and R ₂ cannot both be hydrogen atoms at the same time.)

In the above general formula (1), the tetravalent organic group represented by _X1 is preferably an organic group having 6 to 40 carbon atoms, more preferably an aromatic group in which the _-COOR1 group, _-COOR2 group, and -CONH- group are in the ortho position relative to each other, or an alicyclic aliphatic group. More preferably, an organic group represented by the following formula (5) is mentioned.

From the viewpoint of increasing the resolution of the cured relief pattern while maintaining high film strength, the tetravalent organic group represented by _X1 in the above general formula (1) is preferably selected from at least one of pyromellitic dianhydride (PMDA) and biphenyltetracarboxylic dianhydride (BPDA).

Furthermore, the structure of _X1 may be one type or a combination of two or more types.

一般式（３）中、Ｒ_６～Ｒ_１３は、各々独立に水素原子、ハロゲン原子、又は１価の有機基である。
基板との密着性を発現する観点から、Ｙ_１は、下記一般式（４）で表される形が好ましい。

｛式（４）中、Ｒ_１４及びＲ_１５は、各々独立に、水素原子又は炭化水素から成る１価の有機基である。｝
一般式（３）または一般式（４）の構造を有することで硬化後の膜強度が向上し、かつ良好な硬化レリーフパターンを得ることができる。
また、Ｙ_１の構造は１種でも２種以上の組み合わせでもよい。 In the above general formula (1), _Y1 is a divalent organic group represented by the following general formula (3).

In formula (3), R ₆ to R ₁₃ each independently represent a hydrogen atom, a halogen atom, or a monovalent organic group.
From the viewpoint of exhibiting adhesion to a substrate, _Y1 is preferably a group represented by the following general formula (4).

In formula (4), R ₁₄ and R ₁₅ are each independently a hydrogen atom or a monovalent organic group composed of a hydrocarbon.
By having the structure of general formula (3) or (4), the film strength after curing is improved and a good cured relief pattern can be obtained.
The structure of _Y1 may be one type or a combination of two or more types.

Furthermore, it is preferable that the polyimide precursor (A) is represented by the general formula (1), and at least one of _R1 and _R2 contains a group represented by the general formula (2), and contains a precursor having a double bond at the end of _R1 and _R2 containing the group represented by the general formula (2). By having a double bond at the end of _R1 and _R2 represented by the general formula (2), an even higher effect is achieved.

(A) The polyimide precursor is converted to polyimide by heating (e.g., at 200°C or higher) for cyclization.

[(A) Method for preparing polyimide precursor]
The polyimide precursor represented by the general formula (1) in this embodiment can be obtained, for example, by reacting the above-mentioned tetracarboxylic acid dianhydride containing the tetravalent organic group _X1 having 6 to 40 carbon atoms with (a) an alcohol formed by bonding a monovalent organic group represented by the general formula (2) and a hydroxyl group to prepare a partially esterified tetracarboxylic acid (hereinafter, also referred to as an acid/ester), and then polycondensing the resulting tetracarboxylic acid with a diamine containing a divalent organic group _Y1 represented by the general formula (3).

(Preparation of Acid/Ester Forms)
In this embodiment, examples of tetracarboxylic dianhydrides containing a tetravalent organic group X ₁ having 6 to 40 carbon atoms include pyromellitic anhydride, diphenylether-3,3',4,4'-tetracarboxylic dianhydride, benzophenone-3,3',4,4'-tetracarboxylic dianhydride, biphenyl-3,3',4,4'-tetracarboxylic dianhydride, diphenylsulfone-3,3',4,4'-tetracarboxylic dianhydride, diphenylmethane-3,3',4,4'-tetracarboxylic dianhydride, 2,2-bis(3,4-phthalic anhydride)propane, 2,2-bis(3,4-phthalic anhydride)-1,1,1,3,3,3-hexafluoropropane, etc. Moreover, these can be used alone or in combination of two or more.

(a) Examples of aliphatic alcohols having 5 to 30 carbon atoms or aromatic alcohols having 6 to 30 carbon atoms represented by the above general formula (2) include 1-pentanol, 2-pentanol, 3-pentanol, neopentyl alcohol, 1-heptanol, 2-heptanol, 3-heptanol, 1-octanol, 2-octanol, 3-octanol, 1-nonanol, triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, tetraethylene glycol monomethyl ether, tetraethylene glycol monoethyl ether, and benzyl alcohol.

The content of the component (a) in the negative photosensitive resin composition is preferably more than 80 mol % based on the total content of R ₁ and R _2. When the content of the component (a) exceeds 80 mol %, it is possible to obtain desired photosensitive characteristics, which is preferable.
The content of the component (a) in the negative photosensitive resin composition is preferably 85 mol % or more, more preferably 90 mol % or more, and even more preferably 95 mol % or more, based on the total content of _R1 and _R2 .

By stirring, dissolving and mixing the above tetracarboxylic dianhydride and the above alcohol in a reaction solvent in the presence of a basic catalyst such as pyridine at a reaction temperature of 20 to 50°C for 4 to 10 hours, the half-esterification reaction of the acid dianhydride proceeds, and the desired acid/ester can be obtained.

The reaction solvent is preferably one that dissolves the acid/ester and the polyimide precursor, which is a polycondensation product of the acid/ester and diamines, and examples thereof include N-methyl-2-pyrrolidone, N,N-dimethylacetamide, N,N-dimethylformamide, dimethylsulfoxide, tetramethylurea, gamma-butyrolactone, ketones, esters, lactones, ethers, halogenated hydrocarbons, hydrocarbons, acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, methyl acetate, ethyl acetate, butyl acetate, diethyl oxalate, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, tetrahydrofuran, dichloromethane, 1,2-dichloroethane, 1,4-dichlorobutane, chlorobenzene, o-dichlorobenzene, hexane, heptane, benzene, toluene, xylene, etc. These may be used alone or in combination as needed.

(Preparation of polyimide precursor)
A known dehydration condensation agent, for example, dicyclohexylcarbodiimide, 1-ethoxycarbonyl-2-ethoxy-1,2-dihydroquinoline, 1,1-carbonyldioxy-di-1,2,3-benzotriazole, N,N'-disuccinimidyl carbonate, or the like is added to and mixed with the above acid/ester body (typically a solution in the above reaction solvent) under ice cooling to convert the acid/ester body into a polyacid anhydride, and then a diamine containing a divalent organic group _Y1 of general formula (3) dissolved or dispersed in a separate solvent is added dropwise to the above acid/ester body to polycondense the polyimide precursor that can be used in the embodiment.

Examples of diamines containing a divalent organic group _Y1 that can be preferably used in the present invention include 2,2'-dimethyl-4,4-diaminobiphenyl, 2,2'-bis(trifluoromethyl)-4,4'-diaminobiphenyl, 3,3'-dimethyl-4,4'-diaminobiphenyl, 3,3'-dimethyl-4,4'-diaminodiphenylmethane, 2,2'-dimethyl-4,4'-diaminodiphenylmethane, 2,2'-dimethytoxy-4,4'-diaminobiphenyl, 3,3'-dimethytoxy-4,4'-diaminobiphenyl, 2,2',3,3'-tetramethyl-4,4-diaminobiphenyl, and 3,3'-dichloro-4,4'-diaminobiphenyl. Among these, it is preferable to use 2,2'-dimethyl-4,4'-diaminobiphenyl and 2,2'-dimethytoxy-4,4'-diaminobiphenyl, and it is more preferable to use 2,2'-dimethyl-4,4'-diaminobiphenyl.

In addition, diaminosiloxanes such as 1,3-bis(3-aminopropyl)tetramethyldisiloxane and 1,3-bis(3-aminopropyl)tetraphenyldisiloxane can be copolymerized to improve adhesion to various substrates.

After the reaction is completed, the water-absorbing by-product of the dehydration condensation agent coexisting in the reaction solution is filtered off if necessary, and then a poor solvent such as water, aliphatic lower alcohol, or a mixture thereof is added to the resulting polymer component to precipitate the polymer component. The polymer is purified by repeating redissolution and reprecipitation operations, and then vacuum dried to isolate the desired polyimide precursor. To improve the degree of purification, the polymer solution may be passed through a column packed with an anion-cation exchange resin swollen with an appropriate organic solvent to remove ionic impurities.

The molecular weight of the polyimide precursor (A), as measured by gel permeation chromatography in terms of polystyrene equivalent weight average molecular weight, is preferably 8,000 to 150,000, more preferably 9,000 to 50,000, and particularly preferably 20,000 to 40,000. A weight average molecular weight of 8,000 or more is preferable because of good mechanical properties, while a weight average molecular weight of 150,000 or less is preferable because of good dispersibility in the developer and resolution performance of the relief pattern. Tetrahydrofuran and N-methyl-2-pyrrolidone are recommended as developing solvents for gel permeation chromatography. The molecular weight is determined from a calibration curve prepared using standard monodisperse polystyrene. It is recommended to select the standard monodisperse polystyrene from among the organic solvent-based standard samples STANDARD SM-105 manufactured by Showa Denko KK.

(B) Photopolymerization Initiator The (B) photopolymerization initiator in this embodiment will be described. As the (B) photopolymerization initiator, any compound that is conventionally used as a photopolymerization initiator for UV curing can be selected. For example, as the (B) photopolymerization initiator, benzophenone derivatives such as benzophenone, o-benzoyl methyl benzoate, 4-benzoyl-4'-methyldiphenyl ketone, dibenzyl ketone, fluorenone, etc.; acetophenone derivatives such as 2,2'-diethoxyacetophenone, 2-hydroxy-2-methylpropiophenone, 1-hydroxycyclohexylphenyl ketone, etc.; thioxanthone derivatives such as thioxanthone, 2-methylthioxanthone, 2-isopropylthioxanthone, diethylthioxanthone, etc.; benzyl derivatives such as benzil, benzil dimethyl ketal, benzyl-β-methoxyethyl acetal, etc.; benzoin derivatives such as benzoin, benzoin methyl ether, etc.; 1-phenyl- Preferred examples of the photopolymerization initiator include oximes such as 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, and 1-phenyl-3-ethoxypropanetrione-2-(O-benzoyl)oxime; N-arylglycines such as N-phenylglycine; peroxides such as benzoyl perchloride; and aromatic biimidazoles, but are not limited thereto. These may be used alone or in combination of two or more. Of the above-mentioned (B) photopolymerization initiators, oximes are more preferred, particularly in terms of photosensitivity.

The amount of (B) photopolymerization initiator is 0.1 to 20 parts by mass per 100 parts by mass of (A) polyimide precursor, and from the viewpoint of photosensitivity characteristics, 2 to 15 parts by mass is preferable. By adding 0.1 parts by mass or more of (B) photopolymerization initiator per 100 parts by mass of (A) polyimide precursor, the photosensitive resin composition has excellent photosensitivity, while by adding 20 parts by mass or less, the photosensitive resin composition has excellent thick-film curing properties.

(C) Photopolymerizable Substance The (C) photopolymerizable substance in this embodiment will be described. In order to improve the resolution of the relief pattern, a monomer having a photopolymerizable unsaturated bond can be optionally blended in the negative photosensitive resin composition. As such a monomer, a (meth)acrylic compound that undergoes a radical polymerization reaction with a photopolymerization initiator is preferable, and examples thereof include, but are not limited to, mono- or diacrylates and methacrylates of ethylene glycol or polyethylene glycol, including diethylene glycol dimethacrylate and tetraethylene glycol dimethacrylate, mono- or diacrylates and methacrylates of propylene glycol or polypropylene glycol, mono-, di- or triacrylates and methacrylates of glycerol, cyclohexane diacrylate and dimethacrylate, diacrylates and dimethacrylates of 1,4-butanediol, 1,6-hexafluoropropanediol, and the like. Examples of such compounds include diacrylate and dimethacrylate of Sandiol, diacrylate and dimethacrylate of neopentyl glycol, mono- or diacrylate and methacrylate of bisphenol A, benzene trimethacrylate, isobornyl acrylate and methacrylate, acrylamide and its derivatives, methacrylamide and its derivatives, trimethylolpropane triacrylate and methacrylate, di- or triacrylate and methacrylate of glycerol, di-, tri-, or tetraacrylate and methacrylate of pentaerythritol, and ethylene oxide or propylene oxide adducts of these compounds.

The amount of the monomer having a photopolymerizable unsaturated bond is preferably 1 to 50 parts by mass per 100 parts by mass of the polyimide precursor (A).

(E) Solvent The solvent used as component (E) in the photosensitive resin composition of the present invention is at least one selected from γ-butyrolactone, dimethylsulfoxide, and 3-methoxy-N,N-dimethylpropionamide. The use of these solvents promotes an increase in development time caused by the standing time after the coating process and the bake treatment, and makes it possible to achieve both high film strength and high elongation. These can be used alone or in combination of two or more.

When a solvent that has a higher solubility in (A) the polyimide precursor than the above three types of solvents is used, solvation into the polymer takes precedence even after the coating process and baking treatment, no change in development time is observed, and a film with high elongation cannot be obtained. Furthermore, when a solvent that has a lower solubility in (A) the polyimide precursor than the above three types of solvents is used, problems arise such as the inability to set the desired solids concentration or viscosity, or gelation occurring during frozen storage.

The above solvent can be used in an amount ranging from 30 to 1500 parts by weight, preferably from 100 to 1000 parts by weight, per 100 parts by weight of the polyimide precursor (A), depending on the desired coating thickness and viscosity of the negative photosensitive resin composition.

Furthermore, from the viewpoint of improving the storage stability of the negative photosensitive resin composition, a solvent containing an alcohol is preferred. The alcohol that can be suitably used is typically an alcohol that has an alcoholic hydroxyl group in the molecule and does not have an olefinic double bond. Specific examples include alkyl alcohols such as methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, isobutyl alcohol, and tert-butyl alcohol; lactate esters such as ethyl lactate; propylene glycol monoalkyl ethers such as propylene glycol-1-methyl ether, propylene glycol-2-methyl ether, propylene glycol-1-ethyl ether, propylene glycol-2-ethyl ether, propylene glycol-1-(n-propyl) ether, and propylene glycol-2-(n-propyl) ether; monoalcohols such as ethylene glycol methyl ether, ethylene glycol ethyl ether, and ethylene glycol-n-propyl ether; 2-hydroxyisobutyric acid esters; and dialcohols such as ethylene glycol and propylene glycol. Among these, lactate esters, propylene glycol monoalkyl ethers, 2-hydroxyisobutyrate esters, and ethyl alcohol are preferred, with ethyl lactate, propylene glycol-1-methyl ether, propylene glycol-1-ethyl ether, and propylene glycol-1-(n-propyl) ether being particularly preferred.

When the solvent contains an alcohol that does not have an olefinic double bond, the content of the alcohol that does not have an olefinic double bond in the total solvent is preferably 5% by mass to 50% by mass, and more preferably 10% by mass to 30% by mass, based on the mass of the total solvent. When the content of the alcohol that does not have an olefinic double bond is 5% by mass or more, the storage stability of the negative photosensitive resin composition is good, while when it is 50% by mass or less, the solubility of the (A) polyimide precursor is good, which is preferable.

<Other ingredients>
In this embodiment, the negative photosensitive resin composition may further contain components other than the above components (A) to (D). Examples of the other components include resin components other than the polyimide precursor (A), sensitizers, monomers having a photopolymerizable unsaturated bond, adhesion aids, thermal polymerization inhibitors, azole compounds, hindered phenol compounds, and organic titanium compounds.

In an embodiment, the negative photosensitive resin composition may further contain a resin component other than the polyimide precursor (A). Examples of resin components that can be contained in the negative photosensitive resin composition include polyimide, polyoxazole, polyoxazole precursor, phenolic resin, polyamide, epoxy resin, siloxane resin, and acrylic resin. The amount of these resin components is preferably in the range of 0.01 to 20 parts by weight per 100 parts by weight of the polyimide precursor (A).

In an embodiment, a sensitizer can be optionally blended into the negative photosensitive resin composition to improve photosensitivity. Examples of the sensitizer include Michler's ketone, 4,4'-bis(diethylamino)benzophenone, 2,5-bis(4'-diethylaminobenzal)cyclopentane, 2,6-bis(4'-diethylaminobenzal)cyclohexanone, 2,6-bis(4'-diethylaminobenzal)-4-methylcyclohexanone, 4,4'-bis(dimethylamino)chalcone, 4,4'-bis(diethylamino)chalcone, p-dimethylaminocinnamylidene indane, and the like. Non, p-dimethylaminobenzylidene indanone, 2-(p-dimethylaminophenylbiphenylene)-benzothiazole, 2-(p-dimethylaminophenylvinylene)benzothiazole, 2-(p-dimethylaminophenylvinylene)isonaphthothiazole, 1,3-bis(4'-dimethylaminobenzal)acetone, 1,3-bis(4'-diethylaminobenzal)acetone, 3,3'-carbonyl-bis(7-diethylaminocoumarin), 3-acetone ethyl-7-dimethylaminocoumarin, 3-ethoxycarbonyl-7-dimethylaminocoumarin, 3-benzyloxycarbonyl-7-dimethylaminocoumarin, 3-methoxycarbonyl-7-diethylaminocoumarin, 3-ethoxycarbonyl-7-diethylaminocoumarin, N-phenyl-N'-ethylethanolamine, N-phenyldiethanolamine, N-p-tolyldiethanolamine, N-phenylethanolamine, 4-morpholinobenzophenone, isoamyl dimethylaminobenzoate, isoamyl diethylaminobenzoate, 2-mercaptobenzimidazole, 1-phenyl-5-mercaptotetrazole, 2-mercaptobenzothiazole, 2-(p-dimethylaminostyryl)benzoxazole, 2-(p-dimethylaminostyryl)benzthiazole, 2-(p-dimethylaminostyryl)naphtho(1,2-d)thiazole, 2-(p-dimethylaminobenzoyl)styrene, and the like. These can be used alone or in combination of multiple types (e.g., 2 to 5 types).

The amount of sensitizer to be added is preferably 0.1 to 25 parts by weight per 100 parts by weight of (A) polyimide precursor.

In an embodiment, an adhesive aid can be optionally blended into the negative photosensitive resin composition in order to improve the adhesion between the film formed using the negative photosensitive resin composition and the substrate. Examples of the adhesive aid include γ-aminopropyldimethoxysilane, N-(β-aminoethyl)-γ-aminopropylmethyldimethoxysilane, γ-glycidoxypropylmethyldimethoxysilane, γ-mercaptopropylmethyldimethoxysilane, 3-methacryloxypropyldimethoxymethylsilane, 3-methacryloxypropyltrimethoxysilane, dimethoxymethyl-3-piperidinopropylsilane, diethoxy-3-glycidoxypropylmethylsilane, N-(3-diethoxymethylsilylpropyl)succinimide, N-[3-(triethoxysilyl)propyl]phthalamine, and the like. Examples of such additives include silane coupling agents such as benzophenone-3,3'-bis(N-[3-triethoxysilyl]propylamide)-4,4'-dicarboxylic acid, benzene-1,4-bis(N-[3-triethoxysilyl]propylamide)-2,5-dicarboxylic acid, 3-(triethoxysilyl)propyl succinic anhydride, and N-phenylaminopropyl trimethoxysilane, as well as aluminum-based adhesion promoters such as aluminum tris(ethylacetoacetate), aluminum tris(acetylacetonate), and ethylacetoacetate aluminum diisopropylate.

Among these adhesive aids, it is more preferable to use a silane coupling agent in terms of adhesive strength. The amount of adhesive aid to be added is preferably in the range of 0.5 to 25 parts by mass per 100 parts by mass of the polyimide precursor (A).

In an embodiment, a thermal polymerization inhibitor can be optionally blended to improve the stability of the viscosity and photosensitivity of the negative photosensitive resin composition, particularly when stored in a state of a solution containing a solvent. Examples of thermal polymerization inhibitors that can be used include hydroquinone, N-nitrosodiphenylamine, p-tert-butylcatechol, phenothiazine, N-phenylnaphthylamine, ethylenediaminetetraacetic acid, 1,2-cyclohexanediaminetetraacetic acid, glycol ether diaminetetraacetic acid, 2,6-di-tert-butyl-p-methylphenol, 5-nitroso-8-hydroxyquinoline, 1-nitroso-2-naphthol, 2-nitroso-1-naphthol, 2-nitroso-5-(N-ethyl-N-sulfopropylamino)phenol, N-nitroso-N-phenylhydroxylamine ammonium salt, and N-nitroso-N(1-naphthyl)hydroxylamine ammonium salt.

The amount of thermal polymerization inhibitor to be added is preferably in the range of 0.005 parts by mass to 12 parts by mass per 100 parts by mass of the polyimide precursor (A).

For example, when a substrate made of copper or a copper alloy is used, an azole compound can be optionally blended into the negative photosensitive resin composition to suppress discoloration of the substrate. Examples of the azole compound include 1H-triazole, 5-methyl-1H-triazole, 5-ethyl-1H-triazole, 4,5-dimethyl-1H-triazole, 5-phenyl-1H-triazole, 4-t-butyl-5-phenyl-1H-triazole, 5-hydroxyphenyl-1H-triazole, phenyltriazole, p-ethoxyphenyltriazole, 5-phenyl-1-(2-dimethylaminoethyl)triazole, 5-benzyl-1H-triazole, hydroxyphenyltriazole, 1,5-dimethyltriazole, 4,5-diethyl-1H-triazole, 1H-benzotriazole, 2-(5-methyl-2-hydroxyphenyl)benzotriazole, 2-[2-hydroxy-3,5-bis(α,α-dimethylbenzyl)phenyl]-benzotriazole, and the like. benzotriazole, 2-(3,5-di-t-butyl-2-hydroxyphenyl)benzotriazole, 2-(3-t-butyl-5-methyl-2-hydroxyphenyl)-benzotriazole, 2-(3,5-di-t-amyl-2-hydroxyphenyl)benzotriazole, 2-(2'-hydroxy-5'-t-octylphenyl)benzotriazole, hydroxyphenylbenzotriazole, tolyltriazole, 5-methyl-1H-benzotriazole, 4-methyl-1H-benzotriazole, 4-carboxy-1H-benzotriazole, 5-carboxy-1H-benzotriazole, 1H-tetrazole, 5-methyl-1H-tetrazole, 5-phenyl-1H-tetrazole, 5-amino-1H-tetrazole, 1-methyl-1H-tetrazole, etc. Particularly preferred are tolyltriazole, 5-methyl-1H-benzotriazole, and 4-methyl-1H-benzotriazole. These azole compounds may be used alone or in a mixture of two or more.

The amount of the azole compound is preferably 0.1 to 20 parts by mass per 100 parts by mass of the polyimide precursor (A), and more preferably 0.5 to 5 parts by mass from the viewpoint of photosensitivity characteristics. When the amount of the azole compound per 100 parts by mass of the polyimide precursor (A) is 0.1 part by mass or more, discoloration of the copper or copper alloy surface is suppressed when the negative photosensitive resin composition is formed on copper or a copper alloy, while when the amount is 20 parts by mass or less, photosensitivity is excellent, which is preferable.

In an embodiment, a hindered phenol compound can be optionally blended into the negative photosensitive resin composition to suppress discoloration on copper. Examples of the hindered phenol compound include 2,6-di-t-butyl-4-methylphenol, 2,5-di-t-butyl-hydroquinone, octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate, isooctyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate, 4,4'-methylenebis(2,6-di-t-butylphenol), 4,4'-thio-bis(3-methyl-6-t-butylphenol), 4,4'-butylyl 1,6-hexanediol-bis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate], 2,2-thio-diethylenebis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate], N,N'-hexamethylenebis(3,5-di-t-butyl-4-hydroxy-hydrogen) rosinamide), 2,2'-methylene-bis(4-methyl-6-t-butylphenol), 2,2'-methylene-bis(4-ethyl-6-t-butylphenol), pentaerythrityl-tetrakis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate], tris-(3,5-di-t-butyl-4-hydroxybenzyl)-isocyanurate, 1,3,5-trimethyl-2,4,6-tris(3,5-di-t-butyl-4-hydroxybenzyl)benzene, 1 ,3,5-tris(3-hydroxy-2,6-dimethyl-4-isopropylbenzyl)-1,3,5-triazine-2,4,6-(1H,3H,5H)-trione, 1,3,5-tris(4-t-butyl-3-hydroxy-2,6-dimethylbenzyl)-1,3,5-triazine-2,4,6-(1H,3H,5H)-trione, 1,3,5-tris(4-s-butyl-3-hydroxy-2,6-dimethylbenzyl)-1,3,5-triazine-2,4,6-(1H,3H,5H)-t lion, 1,3,5-tris[4-(1-ethylpropyl)-3-hydroxy-2,6-dimethylbenzyl]-1,3,5-triazine-2,4,6-(1H,3H,5H)-trione, 1,3,5-tris[4-triethylmethyl-3-hydroxy-2,6-dimethylbenzyl]-1,3,5-triazine-2,4,6-(1H,3H,5H)-trione, 1,3,5-tris(3-hydroxy-2,6-dimethyl-4-phenylbenzyl)-1,3,5-triazine-2,4,6- (1H,3H,5H)-trione, 1,3,5-tris(4-t-butyl-3-hydroxy-2,5,6-trimethylbenzyl)-1,3,5-triazine-2,4,6-(1H,3H,5H)-trione, 1,3,5-tris(4-t-butyl-5-ethyl-3-hydroxy-2,6-dimethylbenzyl)-1,3,5-triazine-2,4,6-(1H,3H,5H)-trione, 1,3,5-tris(4-t-butyl-6-ethyl-3-hydroxy-2-methylbenzyl)-1, 3,5-triazine-2,4,6-(1H,3H,5H)-trione, 1,3,5-tris(4-t-butyl-6-ethyl-3-hydroxy-2,5-dimethylbenzyl)-1,3,5-triazine-2,4,6-(1H,3H,5H)-trione, 1,3,5-tris(4-t-butyl-5,6-diethyl-3-hydroxy-2-methylbenzyl)-1,3,5-triazine-2,4,6-(1H,3H,5H)-trione, 1,3,5-tris(4-t-butyl-3-hydroxy- 2-methylbenzyl)-1,3,5-triazine-2,4,6-(1H,3H,5H)-trione, 1,3,5-tris(4-t-butyl-3-hydroxy-2,5-dimethylbenzyl)-1,3,5-triazine-2,4,6-(1H,3H,5H)-trione, 1,3,5-tris(4-t-butyl-5-ethyl-3-hydroxy-2-methylbenzyl)-1,3,5-triazine-2,4,6-(1H,3H,5H)-trione, etc., but are not limited thereto. Among these, 1,3,5-tris(4-t-butyl-3-hydroxy-2,6-dimethylbenzyl)-1,3,5-triazine-2,4,6-(1H,3H,5H)-trione is particularly preferred.

The amount of the hindered phenol compound is preferably 0.1 to 20 parts by mass per 100 parts by mass of the polyimide precursor (A), and more preferably 0.5 to 10 parts by mass from the viewpoint of photosensitivity characteristics. When the amount of the hindered phenol compound per 100 parts by mass of the polyimide precursor (A) is 0.1 part by mass or more, for example, when a negative type photosensitive resin composition is formed on copper or a copper alloy, discoloration and corrosion of the copper or copper alloy is prevented, while when the amount is 20 parts by mass or less, photosensitivity is excellent, which is preferable.

In an embodiment, an organotitanium compound may be used for the purpose of improving elongation after a wet heat durability test.
There are no particular limitations on the organotitanium compounds that can be used so long as an organic chemical substance is bonded to a titanium atom via a covalent bond or an ionic bond.

Specific examples of the organotitanium compound are shown below in I) to VII):
I) Titanium chelate compounds: Among these, titanium chelates having two or more alkoxy groups are more preferred because they provide good storage stability for the negative photosensitive resin composition and a good pattern. Specific examples include titanium bis(triethanolamine) diisopropoxide, titanium di(n-butoxide) bis(2,4-pentanedionate), titanium diisopropoxide bis(2,4-pentanedionate), titanium diisopropoxide bis(tetramethylheptanedionate), titanium diisopropoxide bis(ethylacetoacetate), and the like.

II) Tetraalkoxytitanium compounds: For example, titanium tetra(n-butoxide), titanium tetraethoxide, titanium tetra(2-ethylhexoxide), titanium tetraisobutoxide, titanium tetraisopropoxide, titanium tetramethoxide, titanium tetramethoxypropoxide, titanium tetramethylphenoxide, titanium tetra(n-nonyloxide), titanium tetra(n-propoxide), titanium tetrastearyloxide, titanium tetrakis[bis{2,2-(allyloxymethyl)butoxide}], etc.

III) Titanocene compounds: For example, pentamethylcyclopentadienyltitanium trimethoxide, bis(η5-2,4-cyclopentadiene-1-yl)bis(2,6-difluorophenyl)titanium, bis(η5-2,4-cyclopentadiene-1-yl)bis(2,6-difluoro-3-(1H-pyrrol-1-yl)phenyl)titanium, etc.

IV) Monoalkoxytitanium compounds: For example, titanium tris(dioctylphosphate) isopropoxide, titanium tris(dodecylbenzenesulfonate) isopropoxide, etc.

V) Titanium oxide compounds: For example, titanium oxide bis(pentanedionate), titanium oxide bis(tetramethylheptanedionate), phthalocyanine titanium oxide, etc.

VI) Titanium tetraacetylacetonate compounds: For example, titanium tetraacetylacetonate, etc.

VII) Titanate coupling agents: For example, isopropyl tridodecylbenzenesulfonyl titanate, etc.

Among the above I) to VII), it is preferable that the organic titanium compound is at least one compound selected from the group consisting of the above I) titanium chelate compounds, II) tetraalkoxytitanium compounds, and III) titanocene compounds, from the viewpoint of exhibiting better chemical resistance. In particular, titanium diisopropoxide bis(ethylacetoacetate),
Titanium tetra(n-butoxide) and bis(η5-2,4-cyclopentadien-1-yl)bis(2,6-difluoro-3-(1H-pyrrol-1-yl)phenyl)titanium are preferred.

The amount of these organic titanium compounds added is preferably 0.01 to 10 parts by weight, and more preferably 0.1 to 2 parts by weight, relative to 100 parts by weight of the polyamic acid ester used as component A. If the amount added is less than 0.01 part by weight, the desired adhesion will not be achieved, and if it exceeds 10 parts by weight, storage stability may be poor.

In the photosensitive resin composition of this embodiment, the total amount of components excluding (A) polyimide precursor among all solids contained in the photosensitive resin composition is preferably 26% or more and less than 60% of (A) polyimide precursor. By containing 26% or more, the absolute value of the initial development time after the coating process and the bake treatment can be shortened, leading to improved throughput in the semiconductor manufacturing process. In addition, by making it less than 60%, the film properties after the moist heat durability test can be maintained.

<Method for Producing Cured Relief Pattern>
In this embodiment, the following steps (1) to (4):
(1) A step of applying the negative type photosensitive resin composition of the above-mentioned embodiment onto a substrate to form a photosensitive resin layer on the substrate;
(2) a step of exposing the photosensitive resin layer to light;
(3) developing the exposed photosensitive resin layer to form a relief pattern; and
(4) A method for producing a cured relief pattern can be provided, which includes a step of heat-treating the relief pattern to form a cured relief pattern.

Each step will be described below.
(1) Step of applying a negative photosensitive resin composition onto a substrate to form a photosensitive resin layer on the substrate In this step, the negative photosensitive resin composition of the above-mentioned embodiment is applied onto a substrate, and then dried as necessary to form a photosensitive resin layer. As the application method, a method that has been conventionally used for applying a photosensitive resin composition, such as a method of applying with a spin coater, a bar coater, a blade coater, a curtain coater, a screen printer, etc., or a method of spray application with a spray coater, etc., can be used.

If necessary, the coating film made of the negative photosensitive resin composition can be dried, and examples of the drying method include air drying, heat drying in an oven or on a hot plate, and vacuum drying. It is preferable to dry the coating film under conditions that do not cause imidization of the (A) polyimide precursor in the negative photosensitive resin composition. Specifically, when air drying or heat drying is performed, drying can be performed at 20°C to 140°C for 1 minute to 1 hour. Heating at 100°C to 120°C for 230 to 250 seconds is preferable, and heating at 110°C for 240 seconds is more preferable. In this manner, a photosensitive resin layer can be formed on the substrate.

(2) Step of exposing photosensitive resin layer In this step, the photosensitive resin layer formed in the above step (1) is exposed to an ultraviolet light source or the like through a photomask or reticle having a pattern, or directly, using an exposure device such as a contact aligner, a mirror projection, or a stepper.

After this, for the purpose of improving the photosensitivity, etc., a post-exposure bake (PEB) and/or a pre-development bake may be performed at any combination of temperature and time as necessary. The range of baking conditions is preferably a temperature of 40°C to 120°C and a time of 10 seconds to 240 seconds, but is not limited to this range as long as it does not impair the various properties of the negative photosensitive resin composition.

(3) Step of developing the exposed photosensitive resin layer to form a relief pattern In this step, the unexposed portion of the exposed photosensitive resin layer is developed and removed. As a development method for developing the exposed (irradiated) photosensitive resin layer, any method can be selected from conventionally known photoresist development methods, such as a rotary spray method, a paddle method, and an immersion method accompanied by ultrasonic treatment. After development, post-development baking may be performed at any combination of temperature and time, if necessary, for the purpose of adjusting the shape of the relief pattern.

The developer used for development is preferably, for example, a good solvent for the negative photosensitive resin composition, or a combination of the good solvent and a poor solvent. As the good solvent, for example, N-methyl-2-pyrrolidone, N-cyclohexyl-2-pyrrolidone, N,N-dimethylacetamide, cyclopentanone, cyclohexanone, γ-butyrolactone, α-acetyl-γ-butyrolactone, etc. are preferable. As the poor solvent, for example, toluene, xylene, methanol, ethanol, isopropyl alcohol, ethyl lactate, propylene glycol methyl ether acetate, water, etc. are preferable. When using a mixture of a good solvent and a poor solvent, it is preferable to adjust the ratio of the poor solvent to the good solvent depending on the solubility of the polymer in the negative photosensitive resin composition. In addition, two or more types of each solvent, for example, several types, can be used in combination.

(4) Step of Heating the Relief Pattern to Form a Hardened Relief Pattern In this step, the relief pattern obtained by the above development is heated to disperse the photosensitive component and also imidize the polyimide precursor (A), thereby converting it into a hardened relief pattern made of polyimide. As a method of heat hardening, various methods can be selected, such as a method using a hot plate, a method using an oven, or a method using a temperature-elevating oven that can be set to a temperature program. Heating can be performed, for example, under conditions of 200°C to 400°C for 30 minutes to 5 hours. As the atmospheric gas during heat hardening, air may be used, or an inert gas such as nitrogen or argon may also be used.

<Calculation method for development time increase rate>
The present invention is characterized in that the development time increase rate, represented by the following formula (S1), is 130% or more and less than 200%.
Development time increase rate (%) = ( _DT48 / _DT2 ) x 100 (S1)
DT ₂ and DT ₄₈ respectively represent the development times when evaluated under the following conditions.
That is, in an environment of room temperature 23° C.±1° C., humidity 45%±5%, and yellow light, the photosensitive resin composition is applied onto a silicon wafer using a spin coater, and baked for 240 seconds at 110° C. Note that the coating process is performed so that the film thickness after baking is 10.5 μm.
The obtained coating film on the silicon wafer is left to stand for 2 hours, and then spray-developed using cyclopentanone as a good solvent and propylene glycol methyl ether acetate as a poor solvent without going through an exposure process. At this time, the development time until the coating film on the silicon wafer is completely removed is defined as DT _2. Similarly, when the coating film on the silicon wafer that has been left to stand for 48 hours after the coating process and baking treatment is developed under the above conditions, the development time until the coating film is completely removed is defined as DT ₄₈ .

In the present invention, the development time increase rate is 130% or more and less than 200%, so that the thermoset relief pattern can have both high film strength and high elongation. In order to increase the resolution of the cured relief pattern while maintaining the film strength and elongation at break, the development time increase rate is more preferably 135% or more and less than 160%.
If the development time increase rate is less than 130%, the polymer packing is insufficient and the desired elongation cannot be obtained, whereas if the development time increase rate is 200% or more, it becomes difficult to obtain a uniform relief pattern in the plane, which is unacceptable in terms of production.

This parameter is used to evaluate the properties of the photosensitive resin composition, and does not limit the time from coating to development when actually producing a cured relief pattern. The time from coating to development is not particularly limited as long as it is within a range acceptable for production, but is preferably 1 hour or more and less than 24 hours from the viewpoint of sufficient photocuring of the film and production efficiency.
In the photosensitive resin composition of the present invention, the development time changes at a constant rate of increase with the passage of time from the coating to development. Therefore, by calculating an appropriate development time in advance when preparing a cured relief pattern, it is possible to achieve just the right amount of development.

<Semiconductor Device>
In the present embodiment, there is also provided a semiconductor device having a cured relief pattern obtained by the above-described method for producing a cured relief pattern. Thus, it is possible to provide a semiconductor device having a substrate that is a semiconductor element and a cured relief pattern of polyimide formed on the substrate by the above-described method for producing a cured relief pattern.
The present invention can also be applied to a method for manufacturing a semiconductor device using a semiconductor element as a substrate and including the above-mentioned method for manufacturing a cured relief pattern as part of the steps. The semiconductor device of the present invention can be manufactured by forming the cured relief pattern formed by the above-mentioned method for manufacturing a cured relief pattern as a surface protective film, an interlayer insulating film, an insulating film for rewiring, a protective film for a flip chip device, or a protective film for a semiconductor device having a bump structure, and combining the method with a known method for manufacturing a semiconductor device.

<Display device>
In the present embodiment, a display device is provided that includes a display element and a cured film provided on the upper portion of the display element, and the cured film is the above-mentioned cured relief pattern. Here, the cured relief pattern may be laminated in direct contact with the display element, or may be laminated with another layer sandwiched therebetween. For example, the cured film may be a surface protective film, an insulating film, and a planarizing film for a TFT liquid crystal display element and a color filter element, a protrusion for an MVA type liquid crystal display device, and a partition wall for a cathode of an organic EL element.

In addition to being applicable to the semiconductor devices described above, the negative-type photosensitive resin composition of the present invention is also useful for applications such as interlayer insulation in multilayer circuits, cover coats for flexible copper-clad boards, solder resist films, and liquid crystal alignment films.

The present invention will be described in detail below with reference to examples, but the present invention is not limited thereto. In the examples, comparative examples, and production examples, the physical properties of the polymer or negative photosensitive resin composition were measured and evaluated according to the following methods.

(1) Weight-average molecular weight The weight-average molecular weight (Mw) of each polyimide precursor was measured by gel permeation chromatography (standard polystyrene equivalent). The column used in the measurement was a series of Shodex 805M/806M (trade name) manufactured by Showa Denko K.K., the standard monodisperse polystyrene was Shodex STANDARD SM-105 (manufactured by Showa Denko K.K.), the developing solvent was N-methyl-2-pyrrolidone, and the detector was Shodex RI-930 (trade name) manufactured by Showa Denko K.K.

(2) Evaluation of development time DT ₂ and DT ₄₈ The photosensitive resin composition was spin-coated on a 6-inch silicon wafer so that the film thickness after baking was about 10.5 μm, and pre-baked on a hot plate at 110 ° C for 240 seconds to form a coating film. The wafer was left to stand for 2 hours under an environment of 23 ° C. temperature, 45% humidity, and yellow light, and the time until the film on the wafer was completely dissolved and disappeared using cyclopentanone as a developer at 23 ° C. in a developing machine D-SPIN (manufactured by SOKUDO Co., Ltd.) was defined as DT _2. The wafer that had been left to stand for 48 hours was treated in the same manner, and the time until the film was completely disappeared was defined as DT ₄₈ .
Then, from the developing times _DT2 and _DT48 , the developing time increase rate (%) was calculated by the following formula (S1).
Development time increase rate (%) = ( _DT48 / _DT2 ) x 100 (S1)

(3) Resolution Evaluation of Cured Relief Pattern (Polyimide Coating Film) A 6-inch silicon wafer was spin-coated with a photosensitive resin composition so that the film thickness after curing was about 7 μm, and the wafer was pre-baked on a hot plate at 110° C. for 240 seconds to form a coating film. The coating film was exposed to i-line light at an exposure dose of 400 mJ/cm ² using a stepper NSR2005i11A (Nikon Corporation) having an exposure wavelength of i-line (365 nm) through a test patterned reticle. Next, a rotary spray development was performed using cyclopentanone as a developer at 23° C. in a developing machine D-SPIN (SOKUDO Corporation) for a time multiplied by 1.4 for the time until the unexposed portion was completely dissolved and disappeared, followed by rotary spray rinsing with propylene glycol monomethyl ether acetate for 10 seconds to obtain a relief pattern made of a resin film. Subsequently, the coating was cured in a vertical curing furnace VF200B (manufactured by Koyo Thermo Systems) at 280° C. for 2 hours in a nitrogen atmosphere to obtain a cured relief pattern.

The pattern shape and width of the pattern portion of each pattern obtained were observed under an optical microscope to determine the resolution. Regarding the resolution, a pattern having openings of different areas was formed in the same manner as above by exposure through a test patterned reticle, and if the area of the obtained pattern opening was 1/2 or more of the corresponding pattern mask opening area, it was considered to be resolved, and the length of the mask opening side corresponding to the opening with the smallest area among the resolved openings was taken as the resolution. In addition, the pattern accuracy was evaluated based on the following criteria.
A: The pattern cross section is not tapered, swelling or bridging does not occur, and the resolution is 10 μm or less.Furthermore, the pattern shape does not change when heat cured.
B: The cross section of the pattern does not trail, swelling or bridging does not occur, and the resolution is 12 μm or less.
C: The cross section of the pattern does not trail, swelling or bridging does not occur, and the resolution is 14 μm or less.
D: Does not satisfy any of the above C conditions.

(4) Evaluation of Young's modulus of cured relief pattern (polyimide coating film) A photosensitive resin composition was spin-coated and dried on a 6-inch silicon wafer so that the film thickness after curing was about 7 μm, and then the entire surface was exposed to light and heated at 280° C. for 2 hours in a nitrogen atmosphere using a temperature-rise programmable curing oven (VF-2000 type, manufactured by Koyo Lindberg Co., Ltd.) to obtain a cured relief pattern (thermosetting polyimide coating film). The obtained polyimide coating film was cut into strips with a width of 3 mm using a dicing saw (DAD3350 type, manufactured by DISCO Co., Ltd.), and then peeled off from the silicon wafer using 46% hydrofluoric acid to obtain a polyimide tape. The Young's modulus of the obtained polyimide tape was measured using a tensile tester (UTM-II-20 type, manufactured by Orientec Co., Ltd.) according to ASTM D882-09.
A: Young's modulus is 5.5 GPa or more. B: Young's modulus is 5.0 GPa or more and less than 5.5 GPa. C: Young's modulus is 4.0 GPa or more and less than 4.5 GPa. D: Young's modulus is less than 4.0 GPa.

(5) Elongation of Cured Relief Pattern (Polyimide Coating) A photosensitive resin composition was spin-coated and dried on a 6-inch silicon wafer so that the film thickness after curing was about 7 μm, and then the entire surface was exposed to light and heated at 280° C. for 2 hours in a nitrogen atmosphere using a temperature-programmed curing oven (VF-2000, manufactured by Koyo Lindberg Co., Ltd., Japan) to obtain a cured relief pattern (thermosetting polyimide coating). The obtained polyimide coating was cut into strips with a width of 3 mm using a dicing saw (DAD3350, manufactured by DISCO Co., Ltd.), and then peeled off from the silicon wafer using 46% hydrofluoric acid to obtain a polyimide tape. The elongation of the obtained polyimide tape was measured using a tensile tester (UTM-II-20, manufactured by Orientec Co., Ltd.) according to ASTM D882-09.
A: Elongation of 25% or more B: Elongation of 20% or more and less than 25% C: Elongation of 15% or more and less than 20% D: Elongation of less than 15%

(6) Measurement of elongation before and after HAST test After spin-coating and drying a photosensitive resin composition on a 6-inch silicon wafer so that the film thickness after curing was about 7 μm, the entire surface was exposed to light, and the composition was heated at 280° C. for 2 hours in a nitrogen atmosphere using a temperature-rise programmable curing oven (VF-2000 type, manufactured by Koyo Lindberg Co., Ltd., Japan) to obtain a cured relief pattern (thermosetting polyimide coating film). The obtained polyimide coating film was subjected to a high-temperature accelerated test (abbreviated as HAST, manufactured by Hirayama Seisakusho PC-442R8D, 130° C., 85% RH, 168 hours), cut into strips of 3 mm width using a dicing saw (DAD3350 type, manufactured by DISCO Co., Ltd.), and then peeled off from the silicon wafer using 46% hydrofluoric acid to obtain a polyimide tape. The elongation of the resulting polyimide tape was measured using a tensile tester (UTM-II-20 model, manufactured by Orientec Co., Ltd.) in accordance with ASTM D882-09.
A: Elongation of 25% or more B: Elongation of 20% or more and less than 25% C: Elongation of 15% or more and less than 20% D: Elongation of less than 15%

<Production Example 1> (Synthesis of Polymer A as Resin (A))
147 g (0.5 mol) of 3,3',4,4'-biphenyltetracarboxylic dianhydride (BPDA) was placed in a 2-L separable flask, and 135 g (0.2 mol) of 2-hydroxyethyl methacrylate (HEMA) and 400 ml of γ-butyrolactone were added and stirred at room temperature. 79.1 g of pyridine was added with stirring, and the mixture was stirred for 16 hours.

Next, under ice cooling, a solution of 203 g of dicyclohexylcarbodiimide (DCC) dissolved in 200 ml of γ-butyrolactone was added to the reaction mixture over 40 minutes while stirring, followed by the addition of 94 g (0.44 mol) of 2,2'-dimethyl-4,4-diaminobiphenyl (mTB: m-tolidine) suspended in 280 ml of γ-butyrolactone over 60 minutes while stirring. After further stirring at room temperature for 4 hours, 40 ml of ethyl alcohol was added and stirred for 1 hour, and then 1 liter of γ-butyrolactone was added. The precipitate formed in the reaction mixture was removed by filtration to obtain a reaction liquid.

The resulting reaction solution was added to 4 liters of ethyl alcohol to produce a precipitate consisting of a crude polymer. The crude polymer produced was filtered off and dissolved in 2.5 liters of tetrahydrofuran to obtain a crude polymer solution. The resulting crude polymer solution was dropped into 30 liters of water to precipitate the polymer, and the resulting precipitate was filtered off and then vacuum dried to obtain a powdered polymer (Polymer A). The molecular weight of Polymer A was measured by gel permeation chromatography (standard polystyrene equivalent) to find that the weight average molecular weight (Mw) was 25,000.

<Production Example 2> (A) Synthesis of Polymer B as Resin)
Except for using 82 g (0.35 mol) of pyromellitic anhydride (PMDA) and 39 g of 4,4'-oxydiphthalic dianhydride (ODPA) instead of 147 g of BPDA in Production Example 1, and using 71 g (0.33 mol) of mTB instead of 94 g of mTB and 36 g (0.11 mol) of 2,2'-bis(trifluoromethyl)-4,4-diaminobiphenyl (TFMB), the reaction was carried out in the same manner as in the above Production Example 1 to obtain Polymer B. The molecular weight of Polymer B was measured by gel permeation chromatography (standard polystyrene equivalent) to find that the weight average molecular weight (Mw) was 32,000.

<Production Example 3> (A) Synthesis of Polymer C as Resin)
A reaction was carried out in the same manner as in the above-described Production Example 1, except that 22 g (0.1 mol) of PMDA and 124 g (0.4 mol) of ODPA were used instead of 147 g of BPDA in Production Example 1, to obtain Polymer C. The molecular weight of Polymer C was measured by gel permeation chromatography (standard polystyrene equivalent) to find that the weight average molecular weight (Mw) was 20,000.

<Production Example 4> (A) Synthesis of Polymer D as Resin)
A reaction was carried out in the same manner as in the above-described Production Example 1, except that 54 g (0.25 mol) of PMDA and 77 g (0.25 mol) of 4,4'-oxydiphthalic dianhydride (ODPA) were used instead of the 147 g of BPDA in Production Example 1, to obtain Polymer D. The molecular weight of Polymer D was measured by gel permeation chromatography (standard polystyrene equivalent) to find that the weight average molecular weight (Mw) was 28,000.

<Production Example 5> (A) Synthesis of Polymer E as Resin)
A reaction was carried out in the same manner as in the above-described Production Example 1, except that 65 g (0.3 mol) of PMDA and 62 g (0.2 mol) of 4,4'-oxydiphthalic dianhydride (ODPA) were used instead of 147 g of BPDA in Production Example 1, to obtain Polymer E. The molecular weight of Polymer E was measured by gel permeation chromatography (standard polystyrene equivalent) to find that the weight average molecular weight (Mw) was 27,000.

<Production Example 6> (Synthesis of Polymer F as Resin (A))
A reaction was carried out in the same manner as in the above-described Production Example 1, except that 108 g (0.5 mol) of PMDA was used instead of 147 g of BPDA in Production Example 1, to obtain Polymer F. The molecular weight of Polymer F was measured by gel permeation chromatography (standard polystyrene equivalent) to find that the weight average molecular weight (Mw) was 22,000.

<Production Example 7> (A) Synthesis of Polymer G as Resin)
A reaction was carried out in the same manner as in the above-mentioned Production Example 1, except that 155 g (0.5 mol) of ODPA was used instead of 147 g of BPDA in Production Example 1, to obtain Polymer G. The molecular weight of Polymer G was measured by gel permeation chromatography (standard polystyrene equivalent) to find that the weight average molecular weight (Mw) was 24,000.

<Production Example 8> (A) Synthesis of Polymer H as Resin)
A reaction was carried out in the same manner as in the above-described Production Example 1, except that 155 g (0.5 mol) of ODPA was used instead of 147 g of BPDA and 48 g (0.44 mol) of p-phenylenediamine (pPD) was used instead of 94 g of mTB in Production Example 1, to obtain Polymer H. The molecular weight of Polymer H was measured by gel permeation chromatography (standard polystyrene equivalent) to find that the weight average molecular weight (Mw) was 18,000.

<Production Example 9> (A) Synthesis of Polymer I as Resin)
Except for using 155 g (0.5 mol) of ODPA instead of 147 g of BPDA and 89 g (0.44 mol) of diaminodiphenyl ether (DADPE) instead of 94 g of mTB in Production Example 1, a reaction was carried out in the same manner as in Production Example 1 described above to obtain Polymer I. The molecular weight of Polymer I was measured by gel permeation chromatography (standard polystyrene equivalent) to find that the weight average molecular weight (Mw) was 24,000.

<Production Example 9> (Synthesis of Polymer J as Resin (A))
A reaction was carried out in the same manner as in the above-mentioned Production Example 1, except that 73 g (0.25 mol) of ODPA and 74 g (0.25 mol) of BPDA were used instead of 147 g of BPDA in Production Example 1, to obtain Polymer J. The molecular weight of Polymer J was measured by gel permeation chromatography (standard polystyrene equivalent) to find that the weight average molecular weight (Mw) was 24,000.

Example 1
A negative photosensitive resin composition was prepared using polymer A by the following method, and the prepared composition was evaluated. 100 g of polymer A ((A) polyimide precursor), 5.0 g of 1-phenyl-1,2-propanedione-2-(O-ethoxycarbonyl)-oxime ((B) photopolymerization initiator), 12.0 g of tetraethylene glycol dimethacrylate (NK Ester 4G, Shin-Nakamura Chemical Co., Ltd.) ((C) photopolymerizable material), 12.0 g of N-phenyldiethanolamine, and 1.0 g of N-[3-(triethoxysilyl)propyl]phthalamic acid were dissolved in 150 g of γ-butyrolactone (hereinafter referred to as GBL) ((D) solvent). The viscosity of the obtained solution was adjusted to about 40 poise by further adding a small amount of the solvent to obtain a negative photosensitive resin composition. The composition was evaluated according to the above-mentioned method.

<Examples 2 to 17 and Comparative Examples 1 to 7>
Negative photosensitive resin compositions were prepared in the same manner as in Example 1, except that the ingredients were blended in the blending ratios shown in Table 1, and evaluations were carried out in the same manner as in Example 1. The abbreviations in Table 2 are as follows. The evaluation results are shown in Table 3.
Photopolymerization initiator B: 1-phenyl-1,2-propanedione-2-(O-ethoxycarbonyl)-oxime Photopolymerizable substance C: Tetraethylene glycol dimethacrylate Solvent D-1: γ-butyrolactone Solvent D-2: Dimethyl sulfoxide Solvent D-3: 3-methoxy-N,N-dimethylpropionamide Solvent D-4: N-methylpyrrolidone Sensitizer E: N-phenyldiethanolamine Adhesion aid F: N-[3-(triethoxysilyl)propyl]phthalamic acid Other compounds G: Titanium diisopropoxide bis(ethylacetoacetate)

As is clear from Table 3, the development time increase rate of Examples 1 to 17 is 130% or more, and it is understood that they exhibit a high Young's modulus and high elongation. Among them, those in which the development time increase rate is adjusted to 135% to 159%, such as Examples 1 to 3 and 10 to 12, can achieve both high resolution, high Young's modulus, and high elongation. Furthermore, as in Examples 6 and 15, the addition of an organic titanium compound improves the elongation after the moist heat durability test. Furthermore, it is possible to achieve high resolution by blending two types of polymers, as in Examples 16 to 17.

In contrast, in Comparative Examples 1 to 3, 5, and 7, N-methylpyrrolidone, which is highly soluble in solvents, was used, so the rate of increase in development time was insufficient and high elongation could not be achieved. In Comparative Example 3, the rate of increase in development time was excessive, so the desired cured relief pattern could not be obtained. Comparative Example 5 does not have a biphenyl skeleton, so the film strength is insufficient.

The above describes an embodiment of the present invention, but the present invention is not limited to this and can be modified as appropriate without departing from the spirit of the invention.

By using the negative photosensitive resin composition of the present invention, it is possible to achieve both high film strength and breaking elongation after the coating film is cured, making it possible to stably open via patterns, and it can be suitably used in the field of photosensitive materials that are useful for manufacturing electrical and electronic materials such as semiconductor devices and multilayer wiring boards.

Claims (10)

Ingredients below:
(A) a polyimide precursor;
(B) a photopolymerization initiator,
A photosensitive resin composition comprising (C) a photopolymerizable substance and (D) a solvent, wherein the (A) polyimide precursor is represented by the following general formula (1):
In formula (1), _X1 is a tetravalent organic group having 6 to 40 carbon atoms, and _R1 and _R2 each independently represent a hydrogen atom or a group represented by the following general formula (2):
(wherein R ₃ is a hydrogen atom or an organic group having 1 to 3 carbon atoms, R ₄ and R ₅ are each independently a hydrogen atom or an organic group having 1 to 3 carbon atoms, and m is an integer from 2 to 10), or a saturated aliphatic group having 1 to 4 carbon atoms (provided that R ₁ and R ₂ are not both hydrogen atoms at the same time, and at least one of R ₁ and R ₂ contains a monovalent organic group represented by the general formula (2) above ),
Y ₁ is represented by the following general formula (3):
(wherein R ₆ to R ₁₃ are each independently a hydrogen atom, a fluorine atom, or a monovalent organic group) and is a divalent organic group having 6 to 40 carbon atoms.)
The precursor is represented by
The (D) solvent is selected from at least one of γ-butyrolactone, dimethylsulfoxide, and 3-methoxy-N,N-dimethylpropionamide;
The following formula (S1):
Development time increase rate (%) = ( _DT48 / _DT2 ) x 100 (S1)
(In the formula, DT ₂ and DT ₄₈ represent the time taken for the photosensitive resin composition to be completely dissolved in cyclopentanone as a developer at 23° C. after coating the composition on a silicon wafer and baking at 110° C. for 240 seconds, followed by leaving the composition to stand for 2 hours and 48 hours. Note that in the coating process, the film thickness after baking is 10.5 μm.)
The development time increase rate represented by is 130% or more and less than 200%,
the total amount of components excluding the polyimide precursor (A) in the total solid content contained in the photosensitive resin composition is 30% or more and less than 60% based on the polyimide precursor (A);
A photosensitive resin composition, comprising the photopolymerizable substance (C) in an amount of 1 part by mass or more and 25 parts by mass or less per 100 parts by mass of the polyimide precursor (A). The polyimide precursor (A) is _represented by the following general formula (4):
The photosensitive resin composition according to claim 1, having a structure of: {In formula (4), R ₁₄ and R ₁₅ each independently represent a hydrogen atom or a monovalent organic group composed of a hydrocarbon.} 3. The photosensitive resin composition according to claim 1, wherein in the polyimide precursor (A), the _X1 in the general formula (1) is a tetravalent organic group derived from at least one selected from biphenyltetracarboxylic dianhydride (BPDA) and pyromellitic dianhydride (PMDA). The photosensitive resin composition according to any one of claims 1 to 3, wherein the development time increase rate is 135% or more and less than 160%. The photosensitive resin composition according to any one of claims 1 to 4, which contains at least two types of polyimide precursor (A). The following steps:
(1) A step of applying the photosensitive resin composition according to any one of claims 1 to 5 onto a substrate to form a photosensitive resin layer on the substrate;
(2) a step of exposing the photosensitive resin layer to light;
(3) developing the exposed photosensitive resin layer to form a relief pattern; and (4) heat-treating the relief pattern to form a cured relief pattern. The following steps:
(1) A step of applying the photosensitive resin composition according to any one of claims 1 to 5 onto a substrate to form a photosensitive resin layer on the substrate;
(2) a step of exposing the photosensitive resin layer to light;
(3) developing the exposed photosensitive resin layer to form a relief pattern; and (4) heat-treating the relief pattern to form a cured relief pattern,
(1) A method for producing a cured relief pattern, in which heating is performed at 110° C. for 240 seconds when a photosensitive resin layer is formed by coating. A cured relief pattern comprising a cured product of the photosensitive resin composition according to any one of claims 1 to 5. A semiconductor device comprising a semiconductor element and a cured film provided on the upper portion of the semiconductor element, the cured film being the cured relief pattern according to claim 8. A display device comprising a display element and a cured film provided on the upper portion of the display element, the cured film being the cured relief pattern according to claim 8.