JP6057120B2 - Resin composition, photosensitive element, resist pattern forming method and printed wiring board manufacturing method - Google Patents

Description

  The present invention relates to a resin composition, a photosensitive element, a resist pattern forming method, and a printed wiring board manufacturing method.

Conventionally, in the field of manufacturing printed wiring boards, as a resist material used for etching, plating, etc., a photosensitive resin composition or a support film and a photosensitive resin composition formed on the support film are used. A photosensitive element having a layer (hereinafter referred to as “photosensitive resin layer”) is widely used.
There are negative and positive resist materials, but in recent years, since high resolution is obtained, the use of a positive type in which an exposed portion is removed is expected.
When manufacturing a printed wiring board using a positive photosensitive resin composition, a printed wiring board is manufactured as follows, for example. First, a photosensitive layer containing a positive photosensitive resin composition is formed on a substrate, a predetermined portion of the photosensitive layer is irradiated with actinic rays (pattern exposure), and a portion irradiated with actinic rays (exposed portion) is a developer. Then, the resist pattern is formed by dissolving (developing). Then, the substrate on which the resist pattern is formed is etched or plated to form a wiring pattern, and then the resist pattern is peeled off from the substrate. In this way, a printed wiring board having a wiring pattern formed on the substrate is manufactured.
As a positive resist material, for example, Patent Document 1 discloses (A) an alkali-soluble novolak resin, (B) an ester compound of naphthoquinone-1,2-diazidosulfonic acid, and (C) a specific phenol-based material. A positive photoresist composition containing a compound is described.
Such a conventional positive resist material contains an alkali-soluble resin (component (A) in Patent Document 1) and a photosensitizer (component (B) in Patent Document 1) that hinders dissolution thereof. . Although the unexposed portion of the positive resist material contains an alkali-soluble resin, it is difficult to be removed with a developer (alkaline solution) because a photosensitive agent that prevents dissolution of the positive resist material coexists. On the other hand, the exposed portion of the positive resist material is easily removed by a developer because the photosensitizer is transformed into acid or the like by light, so that dissolution of the alkali-soluble resin is not hindered (in some cases, dissolution is promoted). In the conventional positive resist material, a resist pattern is formed by utilizing the difference in solubility between the unexposed area and the exposed area due to the alteration of the photosensitive agent.
Incidentally, in recent years, reversible addition-fragmentation chain transfer polymerization (RAFT polymerization) has been proposed as a polymerization method for vinyl monomers (for example, Patent Documents 2 to 4).

JP-A-6-208222 JP 2000-515181 A JP 2010-059231 A JP 2007-230947 A

In fields requiring a thick film process, for example, the field of manufacturing the top pole of a recording head (magnetic head), it is required to form a high aspect ratio space pattern under a thick film condition of 3 μm or more. .
However, since conventional positive resist materials are colored, if the film thickness is increased, sufficient light transmission cannot be obtained, and sufficient resolution and sensitivity may not be obtained. Therefore, it is difficult for a conventional positive resist material to form a precise resist pattern under thick film conditions.
In addition, in the conventional positive resist material, it is necessary to keep the molecular weight of the resin low in order to ensure sufficient alkali solubility of the resin. Therefore, with conventional positive resist materials, it is difficult to obtain sufficient film formability and flexibility, and even if a photosensitive element is produced, it is difficult to transfer the photosensitive layer to the substrate because the photosensitive layer is fragile. Met. Under such circumstances, a positive photosensitive element has not been put into practical use, and a positive resist material is generally applied directly on a substrate.
Thus, the conventional positive resist material has problems due to the material.
Accordingly, the present invention provides a resin composition that has a novel photosensitive mechanism different from conventional positive resist materials and can be used as a positive resist material that can provide good sensitivity and resolution even at a high film thickness. The purpose is to provide goods. Another object of the present invention is to provide a photosensitive element using the resin composition, a method for forming a resist pattern, and a method for producing a printed wiring board.

The present invention relates to a polymer compound including a structural unit having a trithiocarbonate skeleton, a structural unit having a urethane bond, and a structural unit derived from a compound having (meth) acrylic acid and an ethylenically unsaturated group, and an actinic ray. A resin composition containing a compound that generates radicals (hereinafter sometimes referred to as “photo radical generator”) is provided.
The trithiocarbonate skeleton in the resin composition of the present invention indicates a structure represented by the following formula (1).

本発明のトリチオカーボネート骨格構造単位を含む高分子化合物からなる樹脂組成物に活性光線を照射すると、光ラジカル発生剤からラジカルが発生する。そして、発生したラジカルによりトリチオカーボネート構造が分解・開裂して、上記高分子化合物が低分子化する。本発明においては、未露光部の上記高分子化合物と露光部の上記高分子化合物の低分子化物との溶解性の差を利用して、現像を行うことができる。
このような感光機構により、本発明の樹脂組成物は、高膜厚であっても良好な感度及び解像性が得られるポジ型レジスト材料として用いることができる。
また、本発明の高分子化合物におけるウレタン結合を有する構造単位とは、下記式（２）で表される構造を示す。

When the resin composition comprising the polymer compound containing the trithiocarbonate skeleton structural unit of the present invention is irradiated with actinic rays, radicals are generated from the photoradical generator. Then, the trithiocarbonate structure is decomposed and cleaved by the generated radical, so that the polymer compound has a low molecular weight. In the present invention, development can be performed by utilizing the difference in solubility between the polymer compound in the unexposed area and the low molecular weight product of the polymer compound in the exposed area.
By such a photosensitive mechanism, the resin composition of the present invention can be used as a positive resist material that can obtain good sensitivity and resolution even when the film thickness is high.
Moreover, the structural unit having a urethane bond in the polymer compound of the present invention indicates a structure represented by the following formula (2).

（上記式（２）中、Ｘは２価の有機基を示す。）
このウレタン結合を有する構造単位が、樹脂組成物の被膜を形成した時に機械特性に優れるものとなる。
本発明の高分子化合物おける（メタ）アクリル酸に由来する構造単位とは、下記式（３）で表される構造を示す。

(In the above formula (2), X represents a divalent organic group.)
This structural unit having a urethane bond is excellent in mechanical properties when a film of the resin composition is formed.
The structural unit derived from (meth) acrylic acid in the polymer compound of the present invention indicates a structure represented by the following formula (3).

式（３）中、ｎは１以上の整数を示し、Ｒ_１はそれぞれ独立に水素原子又はメチル基を示す。ｎが２以上の整数であるとき、複数存在するＲ_１は、それぞれ互いに同じでも異なっていてもよい。
前記高分子化合物（Ａ）は、エチレン性不飽和基を有する化合物に由来する構造単位を更に含むことが好ましく、下記式（４）で表される（メタ）アクリル酸エステルに由来する構造単位を有することがより好ましい。より具体的には、後述の式（１−１）のＲが、前記式（３）で表される（メタ）アクリル酸に由来する構造単位、及び下記式（４）で表される（メタ）アクリル酸エステルに由来する構造単位を含むことが好ましい。
この（メタ）アクリル酸に由来する構造単位により、塩基性の水系現像液により現像可能なポジ型レジスト材料として用いることができる。また、このような繰り返し単位を有する高分子化合物（Ａ）は、透明性に優れる。そのため、このような高分子化合物（Ａ）によれば、解像性及び感度に一層優れる樹脂組成物が得られる。

In formula (3), n represents an integer of 1 or more, and R ₁ each independently represents a hydrogen atom or a methyl group. When n is an integer of 2 or more, a plurality of R ₁ may be the same as or different from each other.
The polymer compound (A) preferably further includes a structural unit derived from a compound having an ethylenically unsaturated group, and a structural unit derived from a (meth) acrylic acid ester represented by the following formula (4): More preferably. More specifically, R in the formula (1-1) described later is represented by the structural unit derived from (meth) acrylic acid represented by the formula (3) and the following formula (4) (meta ) It is preferable to include a structural unit derived from an acrylate ester.
This structural unit derived from (meth) acrylic acid can be used as a positive resist material that can be developed with a basic aqueous developer. In addition, the polymer compound (A) having such a repeating unit is excellent in transparency. Therefore, according to such a polymer compound (A), a resin composition having further excellent resolution and sensitivity can be obtained.

式（４）中、ｎは１以上の整数を示し、Ｒ_１及は水素原子又はメチル基を示し、Ｒ_２は１価の有機基を示す。ｎが２以上の整数であるとき、複数存在するＲ_１及びＲ_２は、それぞれ互いに同じでも異なっていてもよい。
本発明のトリチオカーボネート骨格を有する構造単位、ウレタン結合を有する構造単位、及び（メタ）アクリル酸及びエチレン性不飽和基を有する化合物に由来する構造単位を含む高分子化合物としては、より具体的には、下記式（１−１）で表される構造単位を有することがより好ましい。

In the formula (4), n represents an integer of 1 or more, R ₁ and hydrogen represent a hydrogen atom or a methyl group, and R ₂ represents a monovalent organic group. When n is an integer of 2 or more, a plurality of R ₁ and R ₂ may be the same as or different from each other.
The polymer compound containing the structural unit having a trithiocarbonate skeleton of the present invention, a structural unit having a urethane bond, and a structural unit derived from a compound having (meth) acrylic acid and an ethylenically unsaturated group is more specific. It is more preferable to have a structural unit represented by the following formula (1-1).

［式（１−１）中、ｌ、ｎ、ｍは１以上の整数を示し、Ｒは（メタ）アクリル酸及びエチレン性不飽和基を有する化合物に由来する構造単位、Ｒ_１はそれぞれ独立に水素原子又はアルキル基、Ｒ_２は炭素数１〜１０のアルキレン基、Ｘは２価の有機基、Ａｒは二価の芳香族基を示す。］
このような高分子化合物は、透明性に優れるため、このような高分子化合物を含有する樹脂組成物は、解像性及び感度が一層良好になる。そのため、当該樹脂組成物によれば、高膜厚であっても精密なレジストパターンを形成することができる。
本発明の樹脂組成物において、上記高分子化合物は、ラジカル重合性化合物と、ラジカル重合開始剤と、トリチオカーボネート構造を有する連鎖移動剤との反応を経て得られる両末端に水酸基を有する重合体とジイソシアネート化合物を反応させて得られるポリウレタンであることが好ましい。
このような高分子化合物は、一分子鎖に複数のトリチオカーボネート構造を有している。そのため、活性光線の照射によりトリチオカーボネート構造に結合する炭素原子が解裂した際に、高分子化合物と解裂により生成する低分子化物との溶解性の差を十分に得ることができ、樹脂組成物の解像性が一層向上する。
上記両末端に水酸基を有する重合体としては、下記式（２−１）で表される化合物が挙げられる。

[In Formula (1-1), l, n, and m represent an integer of 1 or more, R is a structural unit derived from a compound having (meth) acrylic acid and an ethylenically unsaturated group, and R ₁ is independently A hydrogen atom or an alkyl group, R ₂ is an alkylene group having 1 to 10 carbon atoms, X is a divalent organic group, and Ar is a divalent aromatic group. ]
Since such a polymer compound is excellent in transparency, a resin composition containing such a polymer compound has better resolution and sensitivity. Therefore, according to the resin composition, a precise resist pattern can be formed even when the film thickness is high.
In the resin composition of the present invention, the polymer compound is a polymer having hydroxyl groups at both ends obtained through a reaction of a radical polymerizable compound, a radical polymerization initiator, and a chain transfer agent having a trithiocarbonate structure. Polyurethane obtained by reacting a diisocyanate compound with diisocyanate is preferable.
Such a polymer compound has a plurality of trithiocarbonate structures in one molecular chain. Therefore, when the carbon atom bonded to the trithiocarbonate structure is cleaved by irradiation with actinic rays, a sufficient difference in solubility can be obtained between the polymer compound and the low molecular weight product produced by cleavage. The resolution of the composition is further improved.
Examples of the polymer having a hydroxyl group at both ends include a compound represented by the following formula (2-1).

［式（２−１）中、Ａｒはそれぞれ独立に、アリール基を示し、Ｒ_１はそれぞれ独立に、水素原子又はアルキル基、Ｒ_２は炭素数１〜１０のアルキレン基を示す。］
このような両末端に水酸基を有する重合体によれば、両末端に水酸基を有し、分子量分布の狭い高分子化合物が得られるため、ジイソシアネート化合物と反応させてポリウレタンを得られ、樹脂組成物の可とう性等の機械特性を容易に制御することができる。

[In Formula (2-1), each Ar independently represents an aryl group, each R ₁ independently represents a hydrogen atom or an alkyl group, and each R ₂ represents a C 1-10 alkylene group. ]
According to such a polymer having a hydroxyl group at both ends, a polymer compound having a hydroxyl group at both ends and a narrow molecular weight distribution can be obtained, so that a polyurethane can be obtained by reacting with a diisocyanate compound. Mechanical properties such as flexibility can be easily controlled.

The present invention also provides a photosensitive element comprising a support and a photosensitive layer comprising the resin composition of the present invention provided on the support.
The photosensitive mechanism in the resin composition of the present invention is as described above. In the present invention, it is not always necessary to keep the molecular weight of the polymer compound low. Therefore, in the resin composition of this invention, the film formation property and flexibility can be suitably adjusted by changing suitably the partial structure and molecular weight of the said high molecular compound.
Therefore, according to the resin composition of the present invention, the above photosensitive element can be provided, and the photosensitive layer of the photosensitive element can be excellent in flexibility.

The present invention also includes a step of forming a photosensitive layer containing the resin composition of the present invention on a substrate, a step of irradiating a predetermined portion of the photosensitive layer with actinic rays, and the predetermined portion of the photosensitive layer as the substrate. And a step of forming a resist pattern containing the resin composition on the substrate by removing from above.
The present invention further provides a method for producing a printed wiring board, comprising a step of etching or plating a substrate on which a resist pattern is formed by the method for forming a resist pattern of the present invention.

  According to the present invention, a resin that has a novel photosensitive mechanism different from that of a conventional positive resist material and can be used as a positive resist material that can obtain good sensitivity and resolution even at a high film thickness. A composition can be provided. In addition, the present invention can provide a photosensitive element, a method for forming a resist pattern, and a method for producing a printed wiring board using the resin composition, and can provide good sensitivity and resolution even when the film thickness is high. Sex is obtained.

It is a schematic cross section which shows one Embodiment of the photosensitive element of this invention.

A preferred embodiment of the present invention will be described below.
(Resin composition)
The resin composition according to this embodiment is a polymer including a structural unit having a trithiocarbonate skeleton, a structural unit having a urethane bond, and a structural unit derived from a compound having (meth) acrylic acid and an ethylenically unsaturated group. The compound (A) and a compound (B) that generates radicals by actinic rays (hereinafter sometimes referred to as “photo radical generator (B)”) are contained.
The polymer compound (A) has a trithiocarbonate structure represented by the following formula (1).
In the present invention, (meth) acrylic acid means acrylic acid, methacrylic acid corresponding thereto, or a mixture thereof.

高分子化合物（Ａ）は、例えば、ラジカルにより上記トリチオカーボネート構造が分解して、トリチオカーボネート構造の一端側に結合する炭素と、他端側に結合する炭素の部分が分解し得るものである。すなわち、分子鎖にｎ個のトリチオカーボネート構造を有する高分子化合物（Ａ）は、活性光線の照射により、ｎ＋１個の低分子化物に分解し得る。
そして、高分子化合物（Ａ）と、分解により生じた低分子化物と、の溶解性の差を利用して、現像を行うことができる。なお、現像液は、後述するように、高分子化合物（Ａ）と低分子化物との溶解性の差が大きいものを適宜選択することができる。
また、高分子化合物（Ａ）は、下記式（２）で表されるウレタン結合を有する構造単位を有する。

In the polymer compound (A), for example, the trithiocarbonate structure is decomposed by radicals, and the carbon bonded to one end of the trithiocarbonate structure and the carbon bonded to the other end can be decomposed. is there. That is, the polymer compound (A) having n trithiocarbonate structures in the molecular chain can be decomposed into n + 1 low molecular weight compounds by irradiation with actinic rays.
Then, development can be performed by utilizing the difference in solubility between the polymer compound (A) and the low molecular weight product generated by decomposition. As described later, a developer having a large difference in solubility between the polymer compound (A) and the low molecular weight product can be appropriately selected.
Moreover, a high molecular compound (A) has a structural unit which has a urethane bond represented by following formula (2).

（上記式（２）中、Ｘは２価の有機基を示す。）
このウレタン結合を有する構造単位が、樹脂組成物の被膜を形成した時に機械特性に優れるものとなる。
また、高分子化合物（Ａ）は、下記式（３）で表される（メタ）アクリル酸に由来する構造単位を有する。

(In the above formula (2), X represents a divalent organic group.)
This structural unit having a urethane bond is excellent in mechanical properties when a film of the resin composition is formed.
Moreover, the high molecular compound (A) has a structural unit derived from (meth) acrylic acid represented by the following formula (3).

［式（３）中、ｎは１以上の整数を示し、Ｒ_１は水素原子又はメチル基を示す。ｎが２以上の整数であるとき、複数存在するＲ_１は、それぞれ互いに同じでも異なっていてもよい。］
また、前記高分子化合物（Ａ）は、エチレン性不飽和基を有する化合物に由来する構造単位を更に含むことが好ましく、下記式（４）で表される（メタ）アクリル酸エステルに由来する構造単位を有することがより好ましい。より具体的には、前記式（１−１）のＲが、前記式（３）で表される（メタ）アクリル酸に由来する構造単位、及び下記式（４）で表される（メタ）アクリル酸エステルに由来する構造単位を含むことが好ましい。

[In formula (3), n represents an integer of 1 or more, and R ₁ represents a hydrogen atom or a methyl group. When n is an integer of 2 or more, a plurality of R ₁ may be the same as or different from each other. ]
Moreover, it is preferable that the said high molecular compound (A) further contains the structural unit derived from the compound which has an ethylenically unsaturated group, and the structure derived from the (meth) acrylic acid ester represented by following formula (4). More preferably it has units. More specifically, R in the formula (1-1) is a structural unit derived from (meth) acrylic acid represented by the formula (3), and (meth) represented by the following formula (4). It is preferable to include a structural unit derived from an acrylate ester.

［式（４）中、ｎは１以上の整数を示し、Ｒ_１及は水素原子又はメチル基を示し、Ｒ_２は１価の有機基を示す。ｎが２以上の整数であるとき、複数存在するＲ_１及びＲ_２は、それぞれ互いに同じでも異なっていてもよい。］
前記（メタ）アクリル酸エステルに由来する構造単位を有する高分子化合物（Ａ）は、解像性及び感度に一層優れる樹脂組成物が得られる。
Ｒ_２における２価の有機基としては、例えば、炭素数１〜２０のアルキル基、フェニル基、ベンジル基等が挙げられる。前記炭素数１〜２０のアルキル基は、直鎖状であっても分岐状であっても、環状あってもよく、炭素数１〜１２のアルキル基であることがより好ましい。Ｒ_２における炭素数１〜２０のアルキル基としては、メチル基、エチル基、プロピル基、ブチル基、ペンチル基、ヘキシル基、ヘプチル基、オクチル基、ノニル基、デシル基、ラウリル基、２−エチルヘキシル基、シクロヘキシル基、シクロヘプチル基、ジシクロペンタニル基、イソボルニル基、アダマンチル基、グリシジル基等が挙げられる。

[In the formula (4), n represents an integer of 1 or more, R ₁ and hydrogen represent a hydrogen atom or a methyl group, and R ₂ represents a monovalent organic group. When n is an integer of 2 or more, a plurality of R ₁ and R ₂ may be the same as or different from each other. ]
With the polymer compound (A) having a structural unit derived from the (meth) acrylic acid ester, a resin composition having further excellent resolution and sensitivity can be obtained.
The divalent organic group represented by R _2, for example, an alkyl group having 1 to 20 carbon atoms, a phenyl group and a benzyl group. The alkyl group having 1 to 20 carbon atoms may be linear, branched or cyclic, and more preferably an alkyl group having 1 to 12 carbon atoms. Examples of the alkyl group having 1 to 20 carbon atoms in R ₂ include methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, heptyl group, octyl group, nonyl group, decyl group, lauryl group, 2-ethylhexyl. Group, cyclohexyl group, cycloheptyl group, dicyclopentanyl group, isobornyl group, adamantyl group, glycidyl group and the like.

The polymer compound (A) may have a thermally crosslinkable group. Here, the heat-crosslinkable group indicates a group capable of forming a crosslinked structure by heating, and the heat-crosslinkable groups may be directly crosslinked, or may be crosslinked via a thermosetting agent. Good.
Examples of the thermally crosslinkable group include a group having an oxirane ring. These thermally crosslinkable groups can be easily crosslinked by heating without being crosslinked by irradiation with actinic rays by appropriately selecting a thermosetting agent. Therefore, a resin composition containing such a polymer compound having a thermally crosslinkable group can be more suitably used as a positive resist material.
Examples of the structure having a thermally crosslinkable group include introducing a structural unit represented by the following formula (5) into R ₂ of the formula (1-1).

式（５）中、ｍは１以上の整数を示し、Ｒ_３は水素原子又はメチル基を示し、Ｒ_４は熱架橋性基を示す。ｍが２以上の整数であるとき、複数存在するＲ_３及びＲ_４は、それぞれ互いに同じでも異なっていてもよい。
Ｒ_４における熱架橋性基としては、オキシラン環を有する基が好ましい。
式（５）で表される構造単位は、例えば、下記式（６）で表される構造単位であることが好ましい。

In formula (5), m represents an integer of 1 or more, R ₃ represents a hydrogen atom or a methyl group, and R ₄ represents a thermally crosslinkable group. When m is an integer of 2 or more, a plurality of R ₃ and R ₄ may be the same as or different from each other.
As the thermally crosslinkable group in R ₄ , a group having an oxirane ring is preferable.
The structural unit represented by the formula (5) is preferably, for example, a structural unit represented by the following formula (6).

式（６）中、ｍ及びＲ_３は式（５）におけるｍ及びＲ_３と同義であり、Ｒ_５は二価の有機基を示す。
Ｒ_５における二価の有機基としては、アルキレン基、アリーレン基、アルキレンオキシ基、シクロアルキレンオキシ基等が挙げられ、これらのうちアルキレン基、アルキレンオキシ基が好ましい。
アルキレン基は、直鎖状であっても分岐状であっても環状であってもよく、炭素数１〜２０のアルキレン基であることが好ましく、炭素数１〜１２のアルキレン基であることがより好ましい。アルキレン基としては、例えば、メチレン基、エチレン基、プロパンジイル基、ヘキサンジイル基、シクロヘキサンジイル基が挙げられる。
アリーレン基としては、フェニレン基等が例示できる。
アルキレンオキシ基は、−Ｒ_６−Ｏ−（Ｒ_６はアルキレン基を示す。）で表される基であり、Ｒ_６におけるアルキレン基としては上記と同様のものが例示できる。
シクロアルキレンオキシ基としては、シクロヘキシルオキシ基等が挙げられる。
高分子化合物（Ａ）は、上記以外の構造を有していてもよく、例えば、後述するエチレン性不飽和基を有する化合物に由来する構造を有していてもよい。

Wherein (6), m and _{R 3} have the same meanings as m and _{R 3} in Formula _{(5), R} 5 is a divalent organic group.
Examples of the divalent organic group for R ₅ include an alkylene group, an arylene group, an alkyleneoxy group, a cycloalkyleneoxy group, and the like. Among these, an alkylene group and an alkyleneoxy group are preferable.
The alkylene group may be linear, branched or cyclic, and is preferably an alkylene group having 1 to 20 carbon atoms, and preferably an alkylene group having 1 to 12 carbon atoms. More preferred. Examples of the alkylene group include a methylene group, an ethylene group, a propanediyl group, a hexanediyl group, and a cyclohexanediyl group.
Examples of the arylene group include a phenylene group.
The alkyleneoxy group is a group represented by —R ₆ —O— (R ₆ represents an alkylene group), and examples of the alkylene group in R ₆ include the same groups as described above.
Examples of the cycloalkyleneoxy group include a cyclohexyloxy group.
The polymer compound (A) may have a structure other than the above, for example, may have a structure derived from a compound having an ethylenically unsaturated group described later.

The polymer compound (A) is obtained through a polymerization reaction of tert-butyl (meth) acrylate, a compound having an ethylenically unsaturated group, a radical polymerization initiator, and a chain transfer agent having a trithiocarbonate structure. A polyurethane polymer obtained by reacting a polymer having a hydroxyl group at both ends with a diisocyanate compound is preferred. A structural unit derived from (meth) acrylic acid is obtained by hydrolyzing the tert-butyl group in the structural unit derived from tert-butyl (meth) acrylate of the polyurethane polymer thus obtained. be able to.
As the compound having an ethylenically unsaturated group, monomers used for reversible addition-fragmentation chain transfer polymerization (RAFT polymerization) can be appropriately used.
Examples of the compound having an ethylenically unsaturated group include styrenes such as styrene and α-methylstyrene in addition to the raw material of the structural unit derived from the (meth) acrylic acid ester (hereinafter referred to as (meth) acrylic acid ester). Acrylamides such as (meth) acrylamide and (meth) acryldimethylamide; (meth) acrylonitrile and the like.
Examples of the (meth) acrylic acid ester include methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, hexyl (meth) acrylate, cyclohexyl (meth) acrylate, (meth) Octyl acrylate, lauryl (meth) acrylate, 2-ethylhexyl (meth) acrylate, dicyclopentanyl (meth) acrylate, isobornyl (meth) acrylate, adamantyl (meth) acrylate, benzyl (meth) acrylate, Examples include glycidyl (meth) acrylate.

As the radical polymerization initiator, a polymerization initiator used for reversible addition-fragmentation chain transfer polymerization (RAFT polymerization) can be appropriately used.
Examples of the radical polymerization initiator include peroxide initiators such as benzoyl peroxide, acetyl peroxide, lauroyl peroxide, di-tert-butyl peroxide, cumene hydroperoxide, tert-butyl hydroperoxide, and dicumyl peroxide; Examples include azo initiators such as AIBN (2,2′-azobisisobutyronitrile) and V-65 (azobisdimethylvaleronitrile). Among these, an azo initiator is preferable, and AIBN is more preferable from the viewpoints that a low boiling point solvent can be used and that side reactions hardly occur.
Examples of the polymer having a hydroxyl group at both ends include a compound represented by the following formula (2-1). According to such a polymer having hydroxyl groups at both ends, a polymer compound having the structure of formula (1-1) can be obtained, and a polymer compound having a narrow molecular weight distribution can be obtained. Mechanical properties such as flexibility of an object can be easily controlled.

式（２−１）中、Ａｒは、アリール基を示し、Ｒ_１はそれぞれ独立に、水素原子又はアルキル基を示し、Ｒ_２は炭素数１〜１０のアルキレン基を示す。
Ａｒにおけるアリール基としては、フェニル基、トリル基等が挙げられる。
Ｒ_１におけるアルキル基としては、直鎖状であっても分岐状であっても環状であってもよく、炭素数１〜２０のアルキル基であることが好ましく、炭素数１〜１２のアルキル基であることがより好ましい。Ｒ_１におけるアルキル基としては、メチル基、エチル基、プロピル基、ブチル基、ペンチル基、ヘキシル基、ヘプチル基、オクチル基、ノニル基、デシル基、シクロヘキシル基、シクロヘプチル基、ジシクロペンタニル基等が挙げられる。
Ｒ_２におけるアルキレン基としては、メチレン基、エチレン基、プロピレン基、ブチレン基、ヘキセン基、オクチレン基、ドデシレン基等が挙げられる。

In formula (2-1), Ar represents an aryl group, R ₁ independently represents a hydrogen atom or an alkyl group, and R ₂ represents an alkylene group having 1 to 10 carbon atoms.
Examples of the aryl group in Ar include a phenyl group and a tolyl group.
The alkyl group for R ₁ may be linear, branched or cyclic, and is preferably an alkyl group having 1 to 20 carbon atoms, and an alkyl group having 1 to 12 carbon atoms. It is more preferable that Examples of the alkyl group in R ₁ include methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, heptyl group, octyl group, nonyl group, decyl group, cyclohexyl group, cycloheptyl group, dicyclopentanyl group. Etc.
Examples of the alkylene group for R ₂ include a methylene group, an ethylene group, a propylene group, a butylene group, a hexene group, an octylene group, and a dodecylene group.

In the said polymerization reaction, the molecular weight of the obtained high molecular compound (A) can be adjusted by controlling the molar ratio of the radically polymerizable compound and radical polymerization initiator with which it uses for a polymerization reaction.
In the above polymerization reaction, the molar ratio of C _{1 /} C ₂ of the amount C _{1 (mol)} and the radical polymerization initiator amount of agent C _{2 (mol)} of the radical polymerizable compound to be subjected to the polymerization reaction, 0.2 It is preferable to set it to -30, and it is more preferable to set it as 1-20. When the molar ratio C ₁ / C ₂ is large, the polymerization reaction tends to be slow while becoming monodisperse, and when the molar ratio C ₁ / C ₂ is small, the radical polymerization initiator directly converts to the radical polymerizable compound. Chain transfer may occur, and a polymer having no trithiocarbonate structure may be by-produced to deteriorate developability.
The polymerization reaction can be performed by solution polymerization, suspension polymerization, emulsion polymerization, solid phase polymerization, and the like. Among these, solution polymerization is preferable from the viewpoint of obtaining a polymer of a polymer compound having a hydroxyl group at both ends having a suitable weight average molecular weight.
In the solution polymerization, for example, a radical polymerizable compound, a radical polymerization initiator, and a chain transfer agent are dissolved in a solvent capable of dissolving the generated polymer compound (A), and heated to a temperature at which the radical polymerization initiator generates radicals. Can be done. The solution polymerization can be performed under conditions such as an air atmosphere; an inert gas atmosphere such as nitrogen or argon; a degassed vacuum; however, it is preferably performed in an inert gas atmosphere such as nitrogen or argon.

The solvent used in the solution polymerization is not particularly limited as long as it is a solvent that can dissolve the polymer compound (A) to be produced, but a solvent having a boiling point higher than the polymerization temperature is preferable. In addition, when using the solvent which has a boiling point lower than polymerization temperature at a normal pressure, superposition | polymerization can also be performed under pressure.
Examples of the solvent include methoxyethanol, ethoxyethanol, toluene, xylene, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanol, butyl acetate, chlorobenzene, dioxane, propylene glycol monomethyl ether, N-methylpyrrolidone, and the like.
In RAFT polymerization, it is generally known that chain transfer from an acrylic growth terminal to a methacrylate monomer hardly occurs. Therefore, when copolymerizing a plurality of radically polymerizable compounds, it is preferable to consider their blending procedures and combinations. For example, when a plurality of radically polymerizable compounds are simultaneously subjected to a polymerization reaction, it is preferable to use a combination of only acrylic monomers, a combination of only methacrylate monomers, and the like. Further, when the polymer is grown stepwise by block polymerization, it is preferable to polymerize the methacrylate monomer and then polymerize the acrylate monomer.
The weight average molecular weight (polystyrene conversion by GPC) of the polymer compound having hydroxyl groups at both ends is usually 1000 or more, preferably 1500 to 20000, and more preferably 2000 to 8000. When the weight average molecular weight is 1000 or more, a resist pattern having high mechanical strength can be obtained. Further, when the weight average molecular weight is 20000 or less, the developability tends to be further improved.

  By reacting a polymer compound having a hydroxyl group at both ends with diisocyanate, polyurethane is produced, and a polymer compound (A) can be obtained. The weight average molecular weight (polystyrene conversion by GPC) of a high molecular compound (A) is 10,000 or more normally, it is preferable that it is 15000-100,000, and it is more preferable that it is 30000-80000. When the weight average molecular weight is 30000 or more, the resist pattern obtained by making a photosensitive element with high mechanical strength can be obtained. Moreover, a low boiling point solvent can be used for the resin composition varnish as a weight average molecular weight is 80000 or less.

As the diisocyanate, either an aliphatic diisocyanate or an aromatic diisocyanate can be used.
As aromatic diisocyanates, 4,4'-diphenylmethane diisocyanate (MDI), 2,4-tolylene diisocyanate (TDI), 2,6-tolylene diisocyanate, naphthalene-1,5-diisocyanate, 2,4-tolylene A dimer etc. can be illustrated.
Examples of the aliphatic diisocyanate include hexamethylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, and isophorone diisocyanate.
Aromatic diisocyanates and aliphatic diisocyanates can be used in combination.
The diisocyanate is preferably used in an equimolar amount relative to the polymer compound having hydroxyl groups at both ends, or at least 1.001 times the polymer compound having hydroxyl groups at both ends. When the amount of diisocyanate is more than equimolar, unreacted isocyanate groups remain and the usable time of the photosensitive element is shortened, which is not preferable. On the other hand, when the polymer compound having hydroxyl groups at both ends is 3 times or more of diisocyanate, the molecular weight of the polymer compound (A) does not increase, and the strength and flexibility of the photosensitive element may be lowered.
The reaction is preferably carried out by solution polymerization, and the solvent used is not particularly limited as long as it is a solvent capable of dissolving the polymer compound (A) produced as described above, but a solvent having a boiling point higher than the polymerization temperature is preferable. . In addition, when using the solvent which has a boiling point lower than polymerization temperature at a normal pressure, superposition | polymerization can also be performed under pressure.
Examples of the solvent include methoxyethanol, ethoxyethanol, toluene, xylene, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanol, butyl acetate, chlorobenzene, dioxane, propylene glycol monomethyl ether, N-methylpyrrolidone, and the like.

  The content of the polymer compound (A) in the resin composition is preferably 80 to 100% by mass and more preferably 90 to 99% by mass based on the total amount of the resin composition.

The photoradical generator (B) is a component that generates radicals upon irradiation with actinic rays and decomposes the trithiocarbonate structure in the polymer compound (A) to lower the polymer compound (A). .
As the photoradical generator (B), those generally known as photoinitiators can be used. For example, benzophenone, p, p-dimethylaminobenzophenone, p, p-diethylaminobenzophenone, p, p Benzophenones such as dichlorobenzophenone; anthraquinones such as 2-ethylanthraquinone and tert-butylanthraquinone; thioxanthones such as 2-chlorothioxanthone; benzoin ethers such as benzoin isopropyl ether and benzoin ethyl ether; benzyls; 4,5-triarylimidazole dimer;
The content of the photoradical generator (B) in the resin composition is preferably 0.1 to 10.0 parts by mass with respect to 100 parts by mass of the total amount of the polymer compound (A), and 0.5 It is more preferable to set it to -5.0 mass parts.

When the polymer compound (A) has a thermally crosslinkable group, the resin composition may contain a thermosetting agent (C). A thermosetting agent is a component which reacts with a heat crosslinkable group and forms a crosslinked structure. The thermosetting agent can be appropriately selected according to the thermally crosslinkable group.
For example, when the polymer compound (A) has an oxirane ring, a known thermosetting agent can be used as the curing agent for the epoxy resin. For example, amine compounds such as aliphatic amines, aromatic amines, and imidazoles; acid anhydrides such as phthalic anhydride and tetrahydrophthalic anhydride; phenol resins; and the like can be suitably used as the thermosetting agent.
The resin composition may contain components other than the above components. For example, the resin composition may contain a plasticizer, a pigment, a filler, an antifoaming agent, a flame retardant, a leveling agent, an antioxidant, and the like as necessary.

(Photosensitive element)
Next, the photosensitive element which concerns on this embodiment is demonstrated. The photosensitive element which concerns on this embodiment is equipped with a support body and the photosensitive layer containing the said resin composition provided on this support body.
FIG. 1 is a schematic cross-sectional view showing a preferred embodiment of the photosensitive element of the present invention. The photosensitive element 1 shown in FIG. 1 includes a support 10 and a photosensitive layer 14 provided on the support 10. The photosensitive layer 14 is a layer formed using the above resin composition. The photosensitive layer 14 is formed, for example, by dissolving the resin composition in a solvent to prepare a resin solution, applying the solution onto the support 10 and drying it. Moreover, the photosensitive element 1 may coat | cover the surface F1 on the opposite side to the support body 10 on the photosensitive layer 14 with a protective film.
Examples of the support 10 include polymer films having heat resistance and solvent resistance, such as polyethylene terephthalate, polypropylene, polyethylene, and polyester. The thickness of the support 10 is preferably 5 to 100 μm, and more preferably 10 to 50 μm. When the thickness is less than 5 μm, the mechanical strength is lowered, and when the photosensitive layer 14 is laminated on the substrate, problems such as breakage of the support 10 tend to occur. On the other hand, if the thickness exceeds 100 μm, the resolution tends to decrease when the photosensitive layer 14 is irradiated with actinic rays via the support 10.
Although the thickness of the photosensitive layer 14 changes with uses, it is the thickness after drying which removed the solvent by heating and / or hot air spraying, and it is preferable that it is 1-100 micrometers, and it is more preferable that it is 3-60 micrometers. Since the photosensitive element 1 forms the photosensitive layer 14 using the above resin composition, a resist pattern can be formed with high accuracy even when the photosensitive layer 14 is thick.
The photosensitive element 1 consisting of two layers of the support 10 and the photosensitive layer 14 or the photosensitive element consisting of three layers of the support 10, the photosensitive layer 14 and the protective film can be suitably used. The element may be stored as it is, or may be wound and stored in a roll shape around a winding core with a protective film interposed.

(Method for forming resist pattern)
Next, a resist pattern forming method according to this embodiment will be described. The resist pattern forming method according to the present embodiment includes a laminating step of forming a photosensitive layer containing the resin composition on a substrate, an exposure step of irradiating a predetermined portion of the photosensitive layer with actinic rays, and the predetermined step of the photosensitive layer. A portion (hereinafter, the predetermined portion after irradiation with actinic rays is referred to as an “exposed portion”, and a portion other than the predetermined portion is referred to as an “unexposed portion”) is removed from the substrate, and the resin is placed on the substrate. And a developing step for forming a resist pattern containing the composition.
Moreover, the method for forming a resist pattern according to the present embodiment is a method for heating a resist pattern containing a resin composition when the polymer compound (A) in the resin composition has a thermally crosslinkable group, thereby forming a fat composition. A heating step of forming a resist pattern including the cured product may be further provided.
As the substrate, an insulating substrate such as silicon or glass can be preferably used.

(Lamination process)
In the laminating step, various methods can be used as a method for forming the photosensitive layer on the substrate. For example, the resin composition can be dissolved in a solvent or a mixed solvent to obtain a solution having a solid content of about 30 to 70% by mass, and then the solution can be applied on a substrate to form a photosensitive layer.
Moreover, you may laminate | stack a photosensitive layer on a board | substrate using the photosensitive element mentioned above. As a laminating method in that case, when the photosensitive element includes a protective film, the protective film is removed, and then the photosensitive layer is heated to about 70 ° C. to about 130 ° C. with a pressure of about 0.1 to 1 MPa on the substrate. Examples of the method include pressure bonding. This method is preferably performed under reduced pressure from the viewpoint of adhesion and followability. Further, in order to further improve the laminating properties, the substrate can be preheated before pressure bonding. These lamination conditions can be changed as appropriate.

(Exposure process)
In the laminating method using a photosensitive element, a photosensitive layer and a support are sequentially laminated on a substrate. When the support has transparency, in the exposure step, the photosensitive layer may be exposed by irradiating actinic rays from the support. When the transparency of the support is low, the support may be removed from the photosensitive layer and directly irradiated with actinic rays.
In the exposure process, for example, actinic rays are irradiated through a negative or positive mask pattern called an artwork. As the active light source, for example, a light source that effectively emits ultraviolet rays, such as a carbon arc lamp, a mercury vapor arc lamp, an ultrahigh pressure mercury lamp, a high pressure mercury lamp, or a xenon lamp is used.

(Development process)
In the development process, the exposed portion is removed from the substrate. In the development step, when a support is present on the photosensitive layer, the support is removed, and then the exposed portion is removed by processing with a developer to produce a resist pattern.

  As the developer, an alkaline aqueous solution, an aqueous developer, an organic solvent or the like that is safe and stable and has good operability is used corresponding to the type of the resin composition. Further, as a developing method, a known method such as spraying, rocking dipping, brushing, scraping or the like is appropriately employed.

  Examples of the base of the alkaline aqueous solution include alkali metals such as lithium hydroxide, sodium hydroxide and potassium hydroxide which are hydroxides of lithium, sodium and potassium, carbonates or bicarbonates such as alkali metals and ammonium. Alkaline carbonate or bicarbonate, alkali metal phosphate sodium phosphate, potassium phosphate, etc., alkali metal pyrophosphate sodium pyrophosphate, potassium pyrophosphate etc., safe and stable, operability The one with good is used.

  Examples of the alkaline aqueous solution include a dilute solution of 0.1 to 5% by mass of sodium carbonate, a dilute solution of 0.1 to 5% by mass of potassium carbonate, and a dilute solution of 0.1 to 5% by mass of sodium hydroxide. A solution, a dilute solution of 0.1 to 5% by mass sodium tetraborate is preferred, and the pH is preferably in the range of 9 to 11. The temperature of the alkaline aqueous solution is adjusted according to the developability of the photosensitive layer, and is preferably 20 to 50 ° C. Furthermore, a small amount of an organic solvent such as a surfactant or an antifoaming agent may be mixed in the alkaline aqueous solution in order to promote development.

  As the aqueous developer, one comprising water and an alkaline aqueous solution or one or more organic solvents is used. Here, as the base of the alkaline aqueous solution, in addition to those described above, for example, borax, sodium metasilicate, tetramethylammonium hydroxide, ethanolamine, ethylenediamine, diethylenetriamine, 2-amino-2-hydroxymethyl-1,3- Examples include propanediol, 1,3-diaminopropanol-2, and morpholine. The pH of such an aqueous developer is preferably as small as possible within a range where development processing can be sufficiently performed, preferably pH 8 to 12, and more preferably pH 9 to 10.

  Examples of the organic solvent include acetone, ethyl acetate, alkoxyethanol having an alkoxy group having 1 to 4 carbon atoms, ethyl alcohol, isopropyl alcohol, butyl alcohol, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, and diethylene glycol monobutyl ether. It is done. The concentration of such an organic solvent is usually preferably 2 to 90% by mass. Moreover, the temperature of such an organic solvent can be adjusted according to developability. Furthermore, such organic solvents can be used alone or in combination of two or more. Examples of the organic solvent-based developer used alone include 1,1,1-trichloroethane, N-methylpyrrolidone, N, N-dimethylformamide, cyclohexanone, methyl isobutyl ketone, and γ-butyrolactone. Furthermore, a small amount of an organic solvent such as a surfactant or an antifoaming agent may be mixed in the alkaline aqueous solution in order to promote development.

(Heating process)
In the heating step, the resist pattern containing the resin composition is heated to a temperature at which the thermally crosslinkable group of the polymer compound (A) and the thermosetting agent in the resin composition can react. The heating temperature can be appropriately selected according to the kind of the thermally crosslinkable group and the thermosetting agent.
The resist pattern that has undergone the heating step can be suitably used as a permanent resist.

(Printed wiring board manufacturing method)
A printed wiring board can be manufactured by etching or plating a substrate on which a resist pattern is formed by the above method. Etching or plating of the substrate is performed on at least one surface of the substrate using the formed resist pattern as a mask.
Etching solutions used for etching include cupric chloride solution, ferric chloride solution, alkaline etching solution, and hydrogen peroxide etching solution. It is preferable to use an iron solution.
The plating methods for plating include copper plating such as copper sulfate plating and copper pyrophosphate plating, solder plating such as high-throw solder plating, watt bath (nickel sulfate-nickel chloride) plating, nickel plating such as nickel sulfamate, Examples thereof include gold plating such as hard gold plating and soft gold plating.
After completion of etching or plating, the resist pattern can be peeled off with a solvent having higher solubility than the solvent used for development. In the case of using a solvent, it is possible to adjust the resist pattern peeling amount by mixing plural kinds of solvents, which is preferable.
Examples of the resist pattern peeling method include an immersion method and a spray method, which may be used alone or in combination. The printed wiring board on which the resist pattern is formed may be a multilayer printed wiring board or may have a small diameter through hole.
The preferred embodiment of the present invention has been described above, but the present invention is not limited to the above embodiment.

EXAMPLES Hereinafter, although an Example demonstrates this invention more concretely, this invention is not limited to an Example.
(Synthesis Example 1: Synthesis of polymer (a) and polymer compound (A))
In a 300 ml flask equipped with a reflux condenser, a nitrogen inlet tube, a stirrer, and a thermometer, 5.69 g (40 mmol) of tert-butyl methacrylate (40 mmol) as an acrylic monomer, lauryl methacrylate (lauryl methacrylate) ) 5.09 g (20 mmol), 3.97 g (20 mmol) of 2-ethylhexyl methacrylate (2-ethylhexyl methacrylate), bis [4- [ethyl-2- (hydroxyethyl) aminocarbonyl] -benzyl as a chain transfer agent ] 10.42 g (20 mmol) of trithiocarbonate (hereinafter sometimes referred to as “RAFT agent A”), 3.28 g (20 mmol) of azobisisobutyronitrile (AIBN) as a radical polymerization initiator, and N as a solvent -Put 114 g of methylpyrrolidinone Was bubbled for 15 minutes gas, the temperature was raised to 75 ° C. water bath. The mixture was reacted for 12 hours to obtain a yellow polymer (a). The number average molecular weight of the polymer (a) was 1320. 5.00 g (20 mmol) of diphenylmethane diisocyanate was added to the reaction solution of the obtained polymer (a), and the temperature was raised to 90 ° C. with an oil bath. After reacting for 3 hours, the reaction solution was used as a polymer compound (A) varnish. The reaction solution was cooled to room temperature (25 ° C.), 10 ml of a 4N hydrochloric acid-ethyl acetate solution was added, and the mixture was stirred for 1 hour. The obtained polymer compound (A) varnish had a solid content of 20% by mass. The number average molecular weight of the polymer compound (A) was 18600, and the acid value was 80 mgKOH / g.
For the polymer (a) and the polymer compound (A), the number average molecular weight (Mn) and the weight average molecular weight (Mw) were measured as follows. The acid value was measured by the potentiometric titration method of JIS K2501.
[Measurement of Mn and Mw]
The number average molecular weight (Mn) and the weight average molecular weight (Mw) of the polymer (a) and the polymer compound (A) were measured by GPC (gel permeation chromatography) and the standard at 25 ° C. Obtained by conversion with polystyrene. Tetrahydrofuran was used as the eluent of GPC, and the column used was a direct connection of TSK-gel Super HZ-3000 and HZ-2000 (both manufactured by Tosoh Corporation).

(Synthesis Examples 2 to 5)
The polymers (b) to (e) and the polymer compounds (B) to (B) are similar to those of Synthesis Example 1 except that the types of the acrylic monomers and the blending amounts of the respective components are changed as shown in Table 1. (E) was obtained. The solid content of the polymer compound varnish is as shown in Table 1.
About each obtained high molecular compound, the number average molecular weight (Mn), the weight average molecular weight (Mw), and the acid value were measured by the method similar to the synthesis example 1. The measurement results are shown in Table 1, respectively.

Example 1
Irg-651 (2,2-dimethoxy-1,2) as a compound (photo radical generator) that generates radicals by actinic rays in 10 g of the polymer compound (A) varnish (solid content 20% by mass N-methylpyrrolidinone solution). -Diphenylethane-1-one, manufactured by BASF Japan Ltd., trade name) 0.10 g was dissolved to prepare a photosensitive varnish. This photosensitive varnish was applied to a polyethylene terephthalate film (Burex A63, manufactured by Teijin Tetron Film Co., Ltd.) with a bar coater so that the thickness after drying (thickness of the photosensitive layer) was 10 μm, 20 μm, and 30 μm, respectively. A photosensitive element was obtained by heating at 120 ° C. for 15 minutes and drying.
Using the obtained photosensitive elements, patterns were prepared and evaluated by the following methods. The evaluation results are shown in Table 2.

[Pattern preparation]
The obtained photosensitive element was laminated on a copper-clad laminate MCL-E-67 (glass epoxy copper foil-clad laminate, manufactured by Hitachi Chemical Co., Ltd., trade name), and a photosensitive layer was provided on the laminate. Subsequently, it exposed through the photomask of a predetermined pattern using the ultraviolet exposure device. The exposure dose was 200 mJ / cm ^{2 for} a thickness of 20 μm and 400 mJ / cm ² for a thickness of 30 μm. Thereafter, the polyethylene terephthalate film was peeled off.
Using the developers shown in Table 2, the case where an image was formed was evaluated as A, and the case where no image was formed was evaluated as B. In addition, regarding the laminating property of the photosensitive element, when the polyethylene terephthalate film was peeled off, the resin layer was peeled off without being transferred to polyethylene terephthalate, and the resin layer was transferred to polyethylene terephthalate and peeling was difficult. The case was evaluated as B.

(Examples 2 to 5)
A photosensitive element was obtained in the same manner as in Example 1 except that the polymer compound (A) was changed to the polymer compounds (B) to (E), respectively.
A pattern was prepared and evaluated in the same manner as in Example 1 using each of the obtained photosensitive elements. The evaluation results are shown in Table 2.

(Examples 6 to 8)
A photoradical generator is N-1717 (1,7-di (acridin-9-yl) heptane, manufactured by Adeka Argus Co., Ltd., trade name), B-CIM (2,2′-bis (2-chlorophenyl)- 4,4 ′, 5,5′-tetraphenylbisimidazole (trade name, manufactured by Hampford)), Irg907 (2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropan-1-one A photosensitive element was obtained in the same manner as in Example 1 except that the product was changed to BASF Japan Ltd., trade name).
A pattern was prepared and evaluated in the same manner as in Example 1 using each of the obtained photosensitive elements. The evaluation results are shown in Table 3.

(Comparative Examples 1-5)
A photosensitive element was obtained in the same manner as in Example 1 except that the photoradical generator was not added to the polymer compounds (A), (B), (C), (D), and (E).
The resulting photosensitive element was irradiated with 1500 mJ / cm ^{2 of} ultraviolet rays, but as shown in Table 4, the film did not dissolve in the developer.

The photosensitive elements of Examples 1 to 8 in which a photoradical generator was blended with a polymer compound having a trithiocarbonate structure were all films, and image formation was possible by ultraviolet exposure and development.
On the other hand, in Comparative Examples 1 to 5 in which no photoradical generator was blended, the film was not dissolved in the developer even when exposed to ultraviolet light, and image formation was not possible.

  DESCRIPTION OF SYMBOLS 1 ... Photosensitive element 1, 10 ... Support body, 14 ... Photosensitive layer

Claims (6)

  A radical is generated by actinic rays and a polymer compound including a structural unit having a trithiocarbonate skeleton, a structural unit having a urethane bond, and a structural unit derived from a compound having (meth) acrylic acid and an ethylenically unsaturated group. And a resin composition containing the compound. The resin composition according to claim 1, wherein the polymer compound has a structural unit represented by the following formula (1-1).

The resin composition according to claim 1 or 2, wherein the polymer having a hydroxyl group at both ends is a compound represented by the following formula (2-1).

A photosensitive element comprising: a support; and a photosensitive layer comprising the resin composition according to any one of claims 1 to 3 provided on the support. Forming a photosensitive layer containing the resin composition according to any one of claims 1 to 3 on a substrate;
  Irradiating a predetermined portion of the photosensitive layer with actinic rays;
  Removing the predetermined portion of the photosensitive layer from the substrate to form a resist pattern containing the resin composition on the substrate;
A method for forming a resist pattern. A method for manufacturing a printed wiring board, comprising a step of etching or plating a substrate on which a resist pattern is formed by the method according to claim 5.

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