WO2023140248A1 - Method for producing lens, radiation-sensitive composition for producing lens, lens, imaging element, imaging device, display element, and display device - Google Patents

Abstract

A lens is produced by a method comprising: a step for applying a radiation-sensitive composition onto a base material to form a coating film; a step for irradiating a portion of the coating film with a radioactive ray to generate an acid in an exposed portion; a step for developing the coating film that has been irradiated with the radioactive ray to form a pattern; a step for irradiating the pattern with a radioactive ray; and a step for heating the pattern after the irradiation of the pattern with the radioactive ray to form a lens. The radiation-sensitive composition comprises at least one polymer (A), a radiation-sensitive acid generator (B) and a solvent(C), in which the polymer (A) contains, in a single molecule or different molecules, a structural unit (a1) having a hydroxyl group bound to an aromatic ring and a structural unit (a2) having such a configuration that an acid-dissociating group is detached by the action of an acid to generate a carboxyl group.

Description

LENS MANUFACTURING METHOD, LENS MANUFACTURING RADIATION SENSITIVE COMPOSITION, LENS, IMAGE SENSOR, IMAGING DEVICE, DISPLAY DEVICE AND DISPLAY DEVICE

[Cross reference to related applications]
This application claims priority from Japanese Patent Application No. 2022-005909 filed on January 18, 2022, the entirety of which is incorporated herein by reference.
TECHNICAL FIELD The present disclosure relates to a lens manufacturing method, a radiation-sensitive composition for lens manufacturing, a lens, an imaging device, an imaging device, a display device, and a display device.

Various image sensors such as CCD (Charge-Coupled Device) image sensors and CMOS (Complementary Metal-Oxide-Semiconductor) image sensors are used as solid-state imaging devices in imaging devices such as cameras. In the solid-state imaging device, minute condensing lenses (hereinafter also referred to as “microlenses”) are regularly arranged in order to collect light on a light receiving element (photodiode) and improve sensor sensitivity. Further, in a display device such as an organic electroluminescence (organic EL) device, a structure in which a microlens is provided on the light emission side of each pixel is adopted in order to improve the light extraction efficiency.

As one of the methods for forming microlenses, a thermal flow method is known in which a pattern corresponding to the microlenses is formed on the upper part of the light receiving element or the light emitting element with a radiation-sensitive composition, and then heat-treated to make it fluid, thereby forming a hemispherical microlens array (see, for example, Patent Document 1).

JP 2020-101659 A

The radiation-sensitive composition used to form the microlens pattern is required to have high radiation sensitivity and to be able to produce microlenses with high chemical resistance and transparency. In addition, in order to ensure a manufacturing margin, a wide temperature range (hereinafter also referred to as "flow margin") in which a favorable microlens pattern can be formed is required.

The present disclosure has been made in view of the above problems, and the main purpose thereof is to provide a lens manufacturing method and a radiation-sensitive composition for lens manufacturing that can obtain a lens that has high radiation sensitivity, a wide flow margin, and excellent chemical resistance and transparency.

According to the present disclosure, the following lens manufacturing method, radiation-sensitive composition for lens manufacturing, lens, imaging device, imaging device, display device, and display device are provided.

[1] A step of applying a radiation-sensitive composition onto a substrate to form a coating film, a step of irradiating a part of the coating film with radiation to generate an acid in an exposed area, a step of developing the radiation-irradiated coating film to form a pattern on the substrate, a step of irradiating the pattern with radiation, and a step of heating the pattern after irradiating the pattern with radiation to form a lens on the substrate, wherein the radiation-sensitive composition comprises a polymer (A) and , a radiation-sensitive acid generator (B), and a solvent (C), wherein the polymer (A) contains, in the same molecule or in different molecules, a structural unit (a1) having a hydroxyl group bonded to an aromatic ring and a structural unit (a2) that produces a carboxyl group when an acid-dissociable group is eliminated by the action of an acid.

[2] A radiation-sensitive composition for manufacturing lenses, containing a polymer (A), a radiation-sensitive acid generator (B), and a solvent (C), wherein the polymer (A) contains, in the same molecule or in different molecules, a structural unit (a1) having a hydroxyl group bonded to an aromatic ring and a structural unit (a2) in which an acid-dissociable group is eliminated by the action of an acid to generate a carboxy group.

[3] A lens formed using the radiation-sensitive composition for manufacturing lenses of [2] above.
[4] An imaging device comprising the lens of [3] above.
[5] An imaging device comprising the imaging element of [4] above.
[6] A display device comprising the lens of [3] above.
[7] A display device comprising the display element of [6] above.

According to the production method of the present disclosure, a coating film is formed on a substrate using the radiation-sensitive composition containing the polymer (A), the radiation-sensitive acid generator (B), and the solvent (C), exposed, developed, and then exposed and heated to form a lens with a wide flow margin and high chemical resistance and transparency. In addition, the radiation-sensitive composition for manufacturing lenses of the present disclosure has high sensitivity to radiation, and can form lenses of good shape with a small irradiation dose.

　Hereinafter, matters related to the embodiment will be explained in detail. In this specification, the numerical range described using "-" means that the numerical values described before and after "-" are included as the lower limit and the upper limit. A "structural unit" is a unit that mainly constitutes a main chain structure, and refers to a structural unit of a chemical structure that includes at least two units in the main chain structure.

≪Lens manufacturing method≫
The manufacturing method of the present disclosure manufactures a lens (hereinafter also referred to as a "microlens") that is a microscopic condensing body provided in a solid-state imaging device (e.g., CCD image sensor, CMOS image sensor) or a display device (e.g., organic EL device or liquid crystal display device), and more specifically, it is based on the thermal flow method. The manufacturing method of the present disclosure includes the following steps (I) to (V).
(I) Step of applying a radiation-sensitive composition for lens manufacturing onto a substrate to form a coating film (II) Step of irradiating a part of the coating film with radiation to generate acid in the exposed area (first exposure step)
(III) A step of developing the coating film irradiated with radiation to form a pattern on the substrate (IV) A step of irradiating the pattern obtained in the above step (III) with radiation (second exposure step)
(V) A step of forming a lens on a substrate by heating the pattern after irradiating the pattern with radiation in the above step (IV). In the following, first, the radiation-sensitive composition for lens manufacturing used in the manufacturing method of the present disclosure will be described, and then each step included in the manufacturing method of the present disclosure will be described.

[Radiation-sensitive composition for manufacturing lenses]
The radiation-sensitive composition for manufacturing lenses of the present disclosure (hereinafter also simply referred to as "the present composition") contains a polymer (A), a radiation-sensitive acid generator (B), and a solvent (C). Unless otherwise specified, each component may be used singly or in combination of two or more.

Here, the term "hydrocarbon group" as used herein means a chain hydrocarbon group, an alicyclic hydrocarbon group and an aromatic hydrocarbon group. A "chain hydrocarbon group" means a straight chain hydrocarbon group or a branched hydrocarbon group that does not contain a cyclic structure in its main chain and is composed only of a chain structure. However, the chain hydrocarbon group may be saturated or unsaturated. The “alicyclic hydrocarbon group” means a hydrocarbon group containing only an alicyclic hydrocarbon structure as a ring structure and not containing an aromatic ring structure. However, the alicyclic hydrocarbon group does not have to consist only of an alicyclic hydrocarbon structure, and may partially have a chain structure. An "aromatic hydrocarbon group" means a hydrocarbon group containing an aromatic ring structure as a ring structure. However, the aromatic hydrocarbon group does not need to consist only of an aromatic ring structure, and may partially contain a chain structure or an alicyclic hydrocarbon structure. In addition, the ring structure which the alicyclic hydrocarbon group and the aromatic hydrocarbon group have may have a substituent consisting of a hydrocarbon structure.

Also, in this specification, "(meth)acryl" means to include "acryl" and "methacryl". "(Meth)acryloyl group" means to include "acryloyl group" and "methacryloyl group". In the present specification, oxiranyl group and oxetanyl group are also referred to as "epoxy group".

<Polymer (A)>
The polymer (A) contains one or both of a structural unit (a1) having a hydroxyl group bonded to an aromatic ring and a structural unit (a2) from which an acid-dissociable group is eliminated by the action of an acid to form a carboxy group. However, the polymer (A) contains the structural unit (a1) and the structural unit (a2) within the same molecule or within different molecules. As long as the polymer (A) contains the structural unit (a1) and the structural unit (a2), it may be composed of one type of polymer, or may be composed of two or more types of polymers.

Specific embodiments of the polymer (A) include the following (I) and (II).
(I) A polymer having a structural unit (a1) and a structural unit (a2) in one molecule.
(II) A mixture of a first polymer having the structural unit (a1) and a second polymer having the structural unit (a2) and different from the first polymer.
The present composition preferably contains, as the polymer (A), a polymer having the structural unit (a1) and the structural unit (a2) in the same molecule, in order to obtain the effect of improving the sensitivity and wide flow margin of the present composition and the chemical resistance of the resulting cured product while minimizing the number of components constituting the present composition.

・ Structural unit (a1)
By including the structural unit (a1) in the polymer (A), it is possible to increase the solubility (alkali solubility) of the polymer (A) in an alkaline developer and enhance the curing reactivity while ensuring the transparency of the microlens formed from the present composition. As used herein, the term "alkali-soluble" means soluble in an alkaline aqueous solution such as a 2.38% by mass concentration tetramethylammonium hydroxide aqueous solution at room temperature.

Examples of the aromatic ring that the structural unit (a1) has include a benzene ring, a naphthalene ring, an anthracene ring, and the like. Among these, a benzene ring or a naphthalene ring is preferred, and a benzene ring is more preferred, from the viewpoint of the permeability of the resulting cured product. The number of hydroxyl groups bonded to the aromatic ring in the structural unit (a1) is not particularly limited. The number of hydroxyl groups bonded to the aromatic ring is preferably 1 to 3, more preferably 1 or 2. A substituent other than a hydroxyl group may be introduced into the aromatic ring of the structural unit (a1). Examples of the substituent include halogen atoms (fluorine atom, chlorine atom, bromine atom, iodine atom, etc.), alkyl groups having 1 to 4 carbon atoms, alkoxy groups having 1 to 4 carbon atoms, fluorinated alkyl groups having 1 to 4 carbon atoms, and the like.

The structural unit (a1) is preferably a structural unit derived from a monomer (hereinafter also referred to as "monomer (M1)") having a structure in which a hydroxyl group is bound to an aromatic ring and a polymerizable unsaturated bond. At least one selected from the group consisting of a (meth)acrylate compound, a (meth)acrylamide compound, a compound having a styrene structure, and a compound having a maleimide structure is preferred as the monomer (M1) in terms of obtaining good patterning properties and resolution. Specifically, the structural unit (a1) is preferably a structural unit derived from at least one selected from the group consisting of compounds represented by the following formula (a1-1) and compounds represented by the following formula (a1-2).

（式（ａ１－１）中、Ｒ ^１は、水素原子、ハロゲン原子、炭素数１～４のアルキル基又は炭素数１～４のフッ素化アルキル基である。Ｒ ^２は、単結合、＊ ^１ －Ｃ（＝Ｏ）－Ｏ－又は＊ ^１ －Ｃ（＝Ｏ）－ＮＨ－である。「＊ ^１ 」は、Ｒ ^１が結合している炭素原子との結合手を表す。Ｒ ^３は、ハロゲン原子、炭素数１～４のアルキル基、炭素数１～４のアルコキシ基又は炭素数１～４のフッ素化アルキル基である。ｍ１は０～４の整数である。ｍ２は１又は２である。ただし、ｍ１＋ｍ２≦５である。ｍ１が２以上の場合、複数のＲ ^３は同一又は異なる。
In formula (a1-2), R ⁴ is a halogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms or a fluorinated alkyl group having 1 to 4 carbon atoms. n1 is an integer of 0-4. n2 is 1 or 2; However, it is n1+n2<=5. When n1 is 2 or more, multiple ^R4 are the same or different. )

In formulas (a1-1) and (a1-2), halogen atoms represented by R ¹ , R ³ and R ⁴ include fluorine, chlorine, bromine and iodine atoms. The alkyl group having 1 to 4 carbon atoms may be linear or branched and includes, for example, methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, sec-butyl group, isobutyl group and tert-butyl group. Examples of the alkoxy group having 1 to 4 carbon atoms include groups in which each group exemplified as the alkyl group having 1 to 4 carbon atoms is bonded to an oxygen atom. Examples of the fluorinated alkyl group having 1 to 4 carbon atoms include groups in which at least one hydrogen atom in each group exemplified as the alkyl group having 1 to 4 carbon atoms is substituted with a fluorine atom.

R ¹ is preferably a hydrogen atom or a methyl group from the viewpoint of copolymerizability of the monomer that gives the structural unit (a1). R ² is preferably a single bond or * ¹ -C(=O)-O-. Each of m1 and n1 is preferably 0 to 2, more preferably 0 or 1.

Specific examples of the structural unit (a1) include structural units represented by the following formulas (1-1) to (1-13).

(In formulas (1-1) to (1-10), R ^A1 is a hydrogen atom, a halogen atom, an alkyl group having 1 to 4 carbon atoms, or a fluorinated alkyl group having 1 to 4 carbon atoms.)

In the polymer (A), the content of the structural unit (a1) is preferably 10 mol% or more, more preferably 15 mol% or more, and even more preferably 25 mol% or more, based on the total structural units constituting the polymer (A), from the viewpoint of imparting good solubility to the polymer (A) in an alkaline developer. On the other hand, if the content of the structural unit (a1) is too high, the difference in solubility in an alkaline developer between the exposed and unexposed areas may become small, making it difficult to obtain a good pattern shape. From this point of view, the content of the structural unit (a1) is preferably 90 mol% or less, more preferably 85 mol% or less, and even more preferably 80 mol% or less, relative to all structural units constituting the polymer (A). When the polymer (A) is composed of two or more types of polymers, the content ratio of the structural unit (a1) refers to the total amount of the structural units (a1) in the two or more types of polymers constituting the polymer (A) (the same applies to the following structural units).

・ Structural unit (a2)
Structural unit (a2) is a structural unit from which an acid dissociable group is eliminated by an acid generated by irradiating the present composition with radiation to form a carboxy group. By including the structural unit (a2) in the polymer (A), the solubility of the polymer (A) in a developer can be changed by exposure to radiation. Thereby, a cured product having a pattern formed thereon can be obtained. Here, the "acid-dissociable group" is a group that substitutes a hydrogen atom of an acid group such as a carboxyl group, and is dissociated by the action of an acid.

In particular, in this composition, by irradiating the composition with radiation, carboxy groups are generated as acid groups in the side chain portions of the polymer (A) in the irradiated region. Utilizing this reaction, it is believed that a further exposure treatment in step (IV) and a heat treatment in step (V) are performed after development, whereby a cross-linking reaction involving carboxy groups proceeds in the presence of acid. As a result of the progress of the cross-linking reaction involving the carboxyl group and the acceleration of the curing, it is believed that the present composition was able to achieve good chemical resistance and a wide flow margin. In addition, it is considered that the further exposure treatment in step (IV) and the heat treatment in step (V) cause cross-linking reactions such as etherification of aromatic rings to proceed also in the structural unit (a1).

Examples of monomers constituting the structural unit (a2) include structural units derived from protected unsaturated carboxylic acids. Examples of unsaturated carboxylic acids include unsaturated monocarboxylic acids, unsaturated dicarboxylic acids, unsaturated acid anhydrides, and unsaturated polyvalent carboxylic acids.

Specific examples of these include unsaturated monocarboxylic acids such as (meth)acrylic acid, crotonic acid, α-chloroacrylic acid, cinnamic acid, 2-(meth)acryloyloxyethyl-succinic acid, 2-(meth)acryloyloxyethylhexahydrophthalic acid, 2-(meth)acryloyloxyethyl-phthalic acid, (meth)acrylic acid-2-carboxyethyl ester, and 4-vinylbenzoic acid. Unsaturated dicarboxylic acids include maleic acid, fumaric acid, itaconic acid, citraconic acid and the like. Examples of unsaturated acid anhydrides include maleic anhydride, itaconic anhydride, and citraconic anhydride. Examples of unsaturated polycarboxylic acids include ω-carboxypolycaprolactone mono(meth)acrylate and the like.

Examples of the acid-dissociable group possessed by the structural unit (a2) include a tertiary alkyl group, an acetal-based functional group, a tertiary alkyl carbonate group, and the like. Among these, a tertiary alkyl group or an acetal functional group is preferable because it is easily dissociated by an acid. When the acid-dissociable group is an acetal-based functional group, the post-exposure bake (PEB) step can be omitted, and the steps can be simplified. The PEB process is a heating process performed after the exposure in the process (II) and before the development in the process (III), and is preferably performed at a lower temperature than the heat treatment in the process (V).

Structural unit (a2) is preferably a structural unit derived from a monomer (hereinafter also referred to as "monomer (M2)") having a structure in which an acid-labile group is eliminated to form a carboxyl group by an acid and a polymerizable unsaturated bond. The structural unit (a2) is preferably a structural unit derived from at least one selected from the group consisting of a compound represented by the following formula (a2-1) and a compound represented by the following formula (a2-2), since it has high solubility in an alkaline developer and can reduce development residue.

（式（ａ２－１）中、Ｒ ^５は、水素原子、ハロゲン原子、炭素数１～４のアルキル基又は炭素数１～４のフッ素化アルキル基である。Ｒ ^６は、単結合、置換若しくは無置換のフェニレン基、又は＊ ^２ －Ｃ（＝Ｏ）－Ｏ－Ｒ ^１５ －である。「＊ ^２ 」は、Ｒ ^５が結合している炭素原子との結合手を表す。Ｒ ^１５は置換若しくは無置換の２価の炭化水素基である。Ｒ ^７は１価の脂肪族炭化水素基である。Ｒ ^８及びＲ ^９は、それぞれ独立して、１価の脂肪族炭化水素基であるか、又はＲ ^８及びＲ ^９が互いに合わせられてＲ ^８及びＲ ^９が結合する炭素原子と共に構成される脂環式構造を表す。
In formula (a2-2), R ¹⁰ is a hydrogen atom, a halogen atom, an alkyl group having 1 to 4 carbon atoms or a fluorinated alkyl group having 1 to 4 carbon atoms. R ¹¹ is a single bond, a substituted or unsubstituted phenylene group, or * ³ -C(=O)-OR ¹⁶ -. "* ³ " represents a bond with the carbon atom to which ^R10 is bonded. R ¹⁶ is a substituted or unsubstituted divalent hydrocarbon group. ^R12 is a hydrogen atom or a monovalent aliphatic hydrocarbon group. R ¹³ and R ¹⁴ represent a cyclic ether structure in which R ¹³ is a monovalent aliphatic hydrocarbon group and R ¹⁴ is a monovalent aliphatic hydrocarbon group, an aralkyl group or a substituted aralkyl group, or R ¹³ and R ¹⁴ are combined with each other and composed together with the carbon atom to which R ¹³ is attached and the oxygen atom to which R ¹⁴ is attached. )

Specific examples of R ⁵ and R ¹⁰ in formulas (a2-1) and (a2-2) include the groups exemplified for R ¹ . R ⁵ and R ¹⁰ are preferably a hydrogen atom or a methyl group from the viewpoint of copolymerizability of the monomer that gives the structural unit (a2).

Regarding R ⁶ and R ¹¹ , the divalent hydrocarbon group represented by R ¹⁵ and R ¹⁶ includes an alkanediyl group having 1 to 5 carbon atoms, a cycloalkanediyl group having 3 to 10 carbon atoms, and a phenylene group. Examples of substituents introduced into the phenylene groups when R ⁶ and R ¹¹ are substituted phenylene groups, and substituents when R ¹⁵ and R ¹⁶ have substituents include halogen atoms, alkyl groups having 1 to 4 carbon atoms, alkoxy groups having 1 to 4 carbon atoms, fluorinated alkyl groups having 1 to 4 carbon atoms, and the like. Specific examples thereof include the groups exemplified in the description of R ¹ .

Examples of monovalent aliphatic hydrocarbon groups represented by R ⁷ to R ⁹ in formula (a2-1) and R ¹² to R ¹⁴ in formula (a2-2) include monovalent alkyl groups having 1 to 10 carbon atoms and monovalent alicyclic hydrocarbon groups having 3 to 20 carbon atoms.

In R ⁷ to R ⁹ and R ¹² to R ¹⁴ , the alkyl group having 1 to 10 carbon atoms may be linear or branched. Specific examples of the alkyl group include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, sec-butyl group, isobutyl group, tert-butyl group, n-pentyl group, isopentyl group, n-hexyl group, n-heptyl group and the like.

In R ⁷ to R ⁹ and R ¹² to R ¹⁴ , the monovalent alicyclic hydrocarbon group having 3 to 20 carbon atoms includes a group obtained by removing one hydrogen atom from a monocyclic or polycyclic saturated alicyclic hydrocarbon. Specific examples of saturated alicyclic hydrocarbons include monocyclic alicyclic hydrocarbons such as cyclopentane, cyclohexane, cycloheptane and cyclooctane. Polycyclic alicyclic hydrocarbons include bicyclo[2.2.1]heptane (norbornane), bicyclo[2.2.2]octane, tricyclo[3.3.1.1 ^3,7 ]decane (adamantane)tetracyclo[6.2.1.1 ^3,6 . 0 ^2,7 ]dodecane and the like.

The substituted or unsubstituted aralkyl group represented by R ¹⁴ includes an aralkyl group having 7 to 20 carbon atoms, and a group in which at least one hydrogen atom of the aralkyl group is substituted with a halogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, and a fluorinated alkyl group having 1 to 4 carbon atoms. Specific examples of aralkyl groups include benzyl, phenethyl, naphthylmethyl, anthrylmethyl, and methylphenylmethyl groups.

The alicyclic structure in which R ⁸ and R ⁹ are combined with each other and formed together with the carbon atoms to which R ⁸ and R ⁹ are bonded includes a group in which two hydrogen atoms are removed from the same carbon atom constituting a monocyclic or polycyclic alicyclic hydrocarbon having 3 to 20 carbon atoms (hereinafter also referred to as a "divalent alicyclic group"). When the divalent alicyclic group is a polycyclic hydrocarbon group, the polycyclic hydrocarbon group may be either a bridged alicyclic hydrocarbon group or a condensed alicyclic hydrocarbon group. The condensed alicyclic hydrocarbon group is a polycyclic alicyclic hydrocarbon group in which a plurality of aliphatic rings share a side (a bond between two adjacent carbon atoms). A bridged alicyclic hydrocarbon group refers to a polycyclic alicyclic hydrocarbon group in which two carbon atoms that are not adjacent to each other among the carbon atoms constituting an alicyclic ring are linked by a linking chain containing one or more carbon atoms.

When R ⁸ and R ⁹ are combined to form a divalent alicyclic group, the divalent alicyclic group is preferably made up of a saturated hydrocarbon in order to increase the solubility of the exposed area in an alkaline developer. Specific examples of monocyclic alicyclic hydrocarbon groups include a cyclopentanediyl group, a cyclohexanediyl group, a cycloheptanediyl group and a cyclooctanediyl group. The polycyclic alicyclic hydrocarbon group is preferably a bridged alicyclic saturated hydrocarbon group, preferably a bicyclo[2.2.1]heptane-2,2-diyl group, a bicyclo[2.2.2]octane-2,2-diyl group or a tricyclo[3.3.1.1 ^3,7 ]decane-2,2-diyl group.

From the viewpoint of increasing the solubility of the exposed area in alkaline developer, R⁸and R⁹is an alkyl group having 1 to 8 carbon atoms or a cycloalkyl group having 3 to 8 carbon atoms, or R⁸and R⁹are aligned with each other and R⁸and R⁹preferably represents a monocyclic or polycyclic alicyclic structure having 3 to 12 carbon atoms formed together with the carbon atoms to which R⁸and R⁹are aligned with each other and R⁸and R⁹more preferably represents a monocyclic saturated alicyclic structure composed of the carbon atoms to which is attached.

The cyclic ether structure formed by combining R ¹³ and R ¹⁴ preferably has 5 or more ring members, more preferably 5 to 12 ring members. Specific examples include a tetrahydrofuran ring structure, a tetrahydropyran ring structure, and the like. When R ¹³ and R ¹⁴ are combined to form a cyclic ether structure, R ¹² is preferably a hydrogen atom, a methyl group or an ethyl group, more preferably a hydrogen atom, because it is easily dissociated by an acid.

Specific examples of the structural unit (a2) include structural units represented by the following formula.

(In the formula, R ^A1 is a hydrogen atom, a halogen atom, an alkyl group having 1 to 4 carbon atoms, or a fluorinated alkyl group having 1 to 4 carbon atoms.)

(In the formula, R ^A1 is a hydrogen atom, a halogen atom, an alkyl group having 1 to 4 carbon atoms, or a fluorinated alkyl group having 1 to 4 carbon atoms.)

The content of the structural unit (a2) is preferably 5 mol% or more, more preferably 10 mol% or more, still more preferably 15 mol% or more, and even more preferably 20 mol% or more, relative to the total structural units constituting the polymer (A). The content of the structural unit (a2) is preferably 60 mol% or less, more preferably 55 mol% or less, and even more preferably 50 mol% or less, relative to all structural units constituting the polymer (A). By setting the content ratio of the structural unit (a2) within the above range, the pattern forming ability of the present composition can be further improved.

The total content of the structural unit (a1) and the structural unit (a2) in the polymer (A) is preferably 50 mol% or more, more preferably 55 mol% or more, still more preferably 60 mol% or more, still more preferably 65 mol% or more, and even more preferably 70 mol% or more, relative to the total structural units constituting the polymer (A). When the total content of the structural unit (a1) and the structural unit (a2) in the polymer (A) is within the above range, the sensitivity to radiation and a wide flow margin of the present composition can be sufficiently ensured, and the effect of improving the chemical resistance of the obtained cured product can be sufficiently obtained.

-Other structural units The polymer (A) may further contain a structural unit different from the structural unit (a1) and the structural unit (a2) (hereinafter also referred to as "another structural unit") together with the structural unit (a1) and the structural unit (a2).

Other structural units include, for example, structural units having an oxetanyl group or an oxiranyl group (hereinafter also referred to as "structural unit (a3)").

・ Structural unit (a3)
Structural unit (a3) is not particularly limited as long as it has an epoxy group. Examples of the structural unit (a3) include a structural unit derived from a monomer having a polymerizable carbon-carbon unsaturated bond and an epoxy group (hereinafter also referred to as "monomer (M3)"). Specific examples of the structural unit (a3) include structural units represented by the following formula (3).

(In formula (3), R ³¹ is a monovalent group having an oxetane structure or an oxirane structure. R ³² is a hydrogen atom or a methyl group. X ³ is a single bond or a divalent linking group.)

In the above formula (3), R ³¹ includes an oxiranyl group, an oxetanyl group, a 3,4-epoxycyclohexyl group, a 3,4-epoxytricyclo[5.2.1.0 ^2,6 ]decyl group, a 3-ethyloxetanyl group and the like. Among these, R ³¹ is preferably a monovalent group having an oxirane structure in terms of high photoreactivity.
Examples of the divalent linking group for ^X3 include alkanediyl groups such as methylene group, ethylene group and 1,3-propanediyl group.

Specific examples of the third monomer include glycidyl (meth)acrylate, 3,4-epoxycyclohexyl (meth)acrylate, 3,4-epoxycyclohexylmethyl (meth)acrylate, 2-(3,4-epoxycyclohexyl)ethyl (meth)acrylate, 3,4-epoxytricyclo[5.2.1.0^2,6] Decyl (meth)acrylate, (3-methyloxetan-3-yl)methyl (meth)acrylate, (3-ethyloxetan-3-yl) (meth)acrylate, (oxetan-3-yl)methyl (meth)acrylate, (3-ethyloxetan-3-yl)methyl (meth)acrylate and the like.

When the polymer (A) contains the structural unit (a3), the epoxy group possessed by the structural unit (a3) acts as a crosslinkable group, thereby improving the resolution of the film obtained using this composition and the chemical resistance of the cured product. On the other hand, when the polymer (A) contains the structural unit (a3), sufficient acid cannot be generated in the exposed area in the exposure step before development, and as a result, there is concern that the radiation sensitivity of the present composition may decrease, or the pattern formability may decrease. Therefore, it is preferable that the polymer (A) does not contain the structural unit (a3), or if it contains the structural unit (a3), the content thereof is relatively small.

Specifically, the content of the structural unit (a3) in the polymer (A) is preferably 0 mol% or more and 15 mol% or less, more preferably 0 mol% or more and 10 mol% or less, still more preferably 0 mol% or more and 5 mol% or less, and even more preferably 0 mol% or more and 1 mol% or less, relative to the total structural units constituting the polymer (A). By setting the content ratio of the structural unit (a3) within the above range, sufficient acid can be generated in the exposed area by radiation irradiation before development, and a cured product having a favorable pattern shape can be obtained by the subsequent development treatment.

In addition to the above, monomers that make up other structural units include (meth)acrylic acid alkyl esters, (meth)acrylic acid esters having an alicyclic structure, (meth)acrylic acid esters having an aromatic ring structure, aromatic vinyl compounds, N-substituted maleimide compounds, monomers having a hydroxyl group (excluding phenolic hydroxyl groups), monomers having a cyclic ether structure (excluding an oxirane structure and an oxetane structure), and monomers having a cyclic carbonate structure. A body etc. are mentioned.

Specific examples of the above monomers include alkyl (meth)acrylates such as methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, n-lauryl (meth)acrylate, and n-stearyl (meth)acrylate. Among these, the alkyl group constituting the alkyl ester portion preferably has 1 to 10 carbon atoms, more preferably 1 to 6 carbon atoms, from the viewpoint of ensuring the heat resistance of the polymer (A).

Examples of (meth)acrylic esters having an alicyclic structure include cyclohexyl (meth)acrylate, 2-methylcyclohexyl (meth)acrylate, tricyclo[5.2.1.0 ^2,6 ]decane-8-yl (meth)acrylate, tricyclo[5.2.1.0 ^2,5 ]decane-8-yloxyethyl (meth)acrylate, and isobornyl (meth)acrylate.

Examples of (meth)acrylic acid esters having an aromatic ring structure include phenyl (meth)acrylate, benzyl (meth)acrylate, naphthylmethyl (meth)acrylate, naphthylethyl (meth)acrylate, phenoxyethyl (meth)acrylate, m-phenoxyphenylmethyl (meth)acrylate, and o-phenylphenoxyethyl (meth)acrylate.

Aromatic vinyl compounds include styrene, 2-methylstyrene, 3-methylstyrene, 4-methylstyrene, α-methylstyrene, 2,4-dimethylstyrene, 2,4-diisopropylstyrene, 5-t-butyl-2-methylstyrene, divinylbenzene, trivinylbenzene, t-butoxystyrene, vinylbenzyldimethylamine, (4-vinylbenzyl)dimethylaminoethyl ether, N,N-dimethylaminoethylstyrene, N,N-dimethylaminomethylstyrene, 2-ethylstyrene, 3-ethylstyrene, 4-ethylstyrene, 2-t-butylstyrene, 3-t-butylstyrene, 4-t-butylstyrene, vinylnaphthalene, vinylpyridine and the like.

Examples of N-substituted maleimide compounds include N-cyclohexylmaleimide, N-cyclopentylmaleimide, N-(2-methylcyclohexyl)maleimide, N-(4-methylcyclohexyl)maleimide, N-(4-ethylcyclohexyl)maleimide, N-(2,6-dimethylcyclohexyl)maleimide, N-norbornylmaleimide, N-tricyclodecylmaleimide, N-adamantylmaleimide, N-phenylmaleimide, N-(2-methylphenyl)maleimide, N-(4-methylphenyl)maleimide, N-(4-ethylphenyl)maleimide, N-(2,6-dimethylphenyl)maleimide, N-benzylmaleimide, N-naphthylmaleimide and the like.

Monomers having hydroxyl groups (excluding phenolic hydroxyl groups) include hydroxymethyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 5-hydroxypentyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, glycerol mono(meth)acrylate, N-(hydroxymethyl)methyl Reimide, N-(2-hydroxyethyl)maleimide, N-(3-hydroxypropyl)maleimide and the like.

Monomers having a cyclic ether structure (excluding an oxirane structure and an oxetane structure) include tetrahydrofurfuryl (meth)acrylate, tetrahydropyranyl (meth)acrylate, 5-ethyl-1,3-dioxan-5-ylmethyl (meth)acrylate, -1,3-dioxan-5-ylmethyl (meth)acrylate, 5-methyl-1,3-dioxan-5-ylmethyl (meth)acrylate, and (2-methyl-2(meth)acrylate). -ethyl-1,3-dioxolan-4-yl)methyl, (2,2-dimethyl-1,3-dioxolan-4-yl)methyl (meth)acrylate, (2,2-dimethyl-1,3-dioxolan-4-yl)ethyl (meth)acrylate, 2-(meth)acryloyloxymethyl-1,4,6-trioxaspiro[4.6]undecane, 2-(meth)acryloyloxymethyl-1,4,6-trioxa spiro[4.4]nonane, 2-(meth)acryloyloxymethyl-1,4,6-trioxaspiro[4.5]decane and the like. Examples of monomers having a cyclic carbonate structure include glycerol carbonate (meth)acrylate and the like.

Monomers constituting other structural units further include unsaturated dicarboxylic acid dialkyl ester compounds such as diethyl itaconate; conjugated diene compounds such as 1,3-butadiene and isoprene; nitrogen-containing vinyl compounds such as (meth)acrylonitrile and (meth)acrylamide; vinyl chloride, vinylidene chloride, vinyl acetate, and the like.

In the polymer (A), the content ratio of other structural units can be appropriately set within a range that does not impair the effects of the present disclosure. The content of other structural units can be, for example, 0 mol% or more and 45 mol% or less, preferably 40 mol% or less, more preferably 35 mol% or less, and still more preferably 30 mol% or less, relative to all structural units constituting the polymer (A). In addition, the content ratio of each structural unit is usually equivalent to the ratio of the monomers used when producing the polymer (A).

Among the above, at least one monomer selected from the group consisting of (meth)acrylic acid alkyl esters, (meth)acrylic acid esters having an alicyclic structure, and (meth)acrylic acid esters having an aromatic ring structure (hereinafter also referred to as "(meth)acrylic acid ester") can be preferably used as the monomer constituting the other structural units, in that it can improve the solubility in an alkaline developer, wide the flow margin, and adjust the chemical resistance of the resulting cured product in a well-balanced manner. The content of structural units derived from (meth)acrylic ester is, for example, 0 mol% or more and 45 mol% or less, more preferably 40 mol% or less, still more preferably 35 mol% or less, and even more preferably 30 mol% or less, relative to all structural units constituting the polymer (A).

In the polymer (A), the weight average molecular weight (Mw) in terms of polystyrene by gel permeation chromatography (GPC) is preferably 2000 or more. When Mw is 2000 or more, it is preferable in that a cured product having sufficiently high heat resistance and chemical resistance and good developability can be obtained. Mw is more preferably 5000 or more, still more preferably 6000 or more. In addition, Mw is preferably 50,000 or less, more preferably 30,000 or less, even more preferably 20,000 or less, and even more preferably 18,000 or less, from the viewpoint of improving film formability.

In the polymer (A), the molecular weight distribution (Mw/Mn) represented by the ratio of the weight average molecular weight (Mw) to the number average molecular weight (Mn) is preferably 4.0 or less, more preferably 3.0 or less. In addition, when the polymer (A) consists of two or more kinds of polymers, it is preferable that Mw and Mw/Mn of each polymer respectively satisfy the above ranges.

The content of the polymer (A) is preferably 20% by mass or more, more preferably 40% by mass or more, and even more preferably 50% by mass or more, relative to the total amount of solids contained in the present composition (that is, the total mass of components other than the solvent (C) in the radiation-sensitive composition). Moreover, the content of the polymer (A) is preferably 99% by mass or less, more preferably 97% by mass or less, relative to the total amount of solids contained in the present composition. By setting the content of the polymer (A) within the above range, it is possible to obtain a cured product that exhibits sufficiently high heat resistance and chemical resistance, as well as good developability and transparency.

The method for synthesizing the polymer (A) is not particularly limited. Polymer (A), for example, using a monomer capable of introducing each structural unit described above, in a suitable polymerization solvent, in the presence of a polymerization initiator, etc., according to a known method such as radical polymerization It can be produced. In the case of radical polymerization, the polymerization initiator used includes azo compounds such as 2,2'-azobis(isobutyronitrile), 2,2'-azobis(2,4-dimethylvaleronitrile), and 2,2'-azobis(isobutyrate) dimethyl. The proportion of the polymerization initiator used is preferably 0.01 to 30 parts by mass with respect to 100 parts by mass of the total amount of monomers used in the reaction. Examples of the polymerization solvent include organic solvents such as alcohols, ethers, ketones, esters and hydrocarbons.

In the above polymerization reaction, the reaction temperature is usually 30°C to 180°C. The reaction time varies depending on the type of polymerization initiator and monomers and the reaction temperature, but is usually 0.5 to 10 hours. The amount of the polymerization solvent used is preferably such that the total amount of the monomers used in the reaction is 0.1 to 60% by mass with respect to the total amount of the reaction solution. The polymer obtained by the polymerization reaction can be isolated using a known isolation method such as, for example, pouring the reaction solution into a large amount of poor solvent, drying the resulting precipitate under reduced pressure, or distilling off the reaction solution under reduced pressure using an evaporator.

<Radiation-sensitive acid generator (B)>
The radiation-sensitive acid generator (B) (hereinafter also simply referred to as "acid generator (B)") contained in the present composition may be any substance that generates an acid upon exposure to radiation and eliminates the acid-dissociable groups of the components of the composition. Specifically, a compound that responds to radiation with a wavelength of 300 nm or more (preferably 300 to 450 nm) and generates an acid can be preferably used. When an acid generator (B) that does not directly respond to radiation with a wavelength of 300 nm or longer is used, it may be used in combination with a sensitizer so that it responds to radiation with a wavelength of 300 nm or longer and generates an acid. The acid generator (B) may further generate an acid by heating. As the acid generator (B), an acid-generating compound having an acid dissociation constant (pKa) of 4.0 or less can be preferably used. In this specification, "radiation" is a concept including visible light, ultraviolet light, deep ultraviolet light, X-rays and charged particle beams.

A known compound that generates an acid in response to radiation can be used as the acid generator (B). Specific examples of the acid generator (B) include, for example, oxime sulfonate compounds, sulfonimide compounds, onium salts, halogen-containing compounds (trichloromethyl-s-triazine compounds, etc.), diazomethane compounds, sulfone compounds, sulfonic acid ester compounds, carboxylic acid ester compounds, and the like.

Specific examples thereof include, for example, oxime sulfonate compounds such as (5-propylsulfonyloxyimino-5H-thiophen-2-ylidene)-(2-methylphenyl)acetonitrile, (5-octylsulfonyloxyimino-5H-thiophen-2-ylidene)-(2-methylphenyl)acetonitrile, (camphorsulfonyloxyimino-5H-thiophen-2-ylidene)-(2-methylphenyl)acetonitrile, (5 -p-toluenesulfonyloxyimino-5H-thiophen-2-ylidene)-(2-methylphenyl)acetonitrile, (2-[2-(4-methylphenylsulfonyloxyimino)]-2,3-dihydrothiophen-3-ylidene]-2-(2-methylphenyl)acetonitrile), 2-(octylsulfonyloxyimino)-2-(4-methoxyphenyl)acetonitrile, and derivatives thereof, WO 2016/1 24493, and the like. Commercially available oxime sulfonate compounds include Irgacure PAG121 manufactured by BASF.

Specific examples of sulfonimide compounds include N-(trifluoromethylsulfonyloxy)succinimide, N-(camphorsulfonyloxy)succinimide, N-(4-methylphenylsulfonyloxy)succinimide, N-(2-trifluoromethylphenylsulfonyloxy)succinimide, N-(4-fluorophenylsulfonyloxy)succinimide, N-(trifluoromethylsulfonyloxy)phthalimide, N-(camphorsulfonyloxy)phthalimide, N-(2 -trifluoromethylphenylsulfonyloxy)phthalimide, N-(2-fluorophenylsulfonyloxy)phthalimide, N-(trifluoromethylsulfonyloxy)diphenylmaleimide, N-(camphorsulfonyloxy)diphenylmaleimide, 4-methylphenylsulfonyloxy)diphenylmaleimide, trifluoromethanesulfonic acid-1,8-naphthalimide, and derivatives thereof.

Onium salts include diphenyliodonium salts, triphenylsulfonium salts, sulfonium salts, quaternary ammonium salts, benzothiazonium salts, tetrahydrothiophenium salts and the like. Specific examples thereof include diphenyliodonium salts such as diphenyliodonium tetrafluoroborate and diphenyliodonium hexafluorophosphonate; and triphenylsulfonium salts such as triphenylsulfonium trifluoromethanesulfonate, triphenylsulfonium camphorsulfonate, triphenylsulfonium tetrafluoroborate, triphenylsulfonium trifluoroacetate, triphenylsulfonium-p-toluenesulfonate, and triphenylsulfonium butyltris(2,6-difluorophenyl)borate. .

Examples of sulfonium salts include benzylsulfonium salts, dibenzylsulfonium salts, substituted benzylsulfonium salts, and the like. Examples of alkylsulfonium salts include alkylsulfonium salts such as 4-acetoxyphenyldimethylsulfonium hexafluoroantimonate and 4-acetoxyphenyldimethylsulfonium hexafluoroarsenate; benzylsulfonium salts such as benzyl-4-hydroxyphenylmethylsulfonium hexafluoroantimonate and benzyl-4-hydroxyphenylmethylsulfonium hexafluorophosphate; dibenzylsulfonium salts such as dibenzyl-4-hydroxyphenylsulfonium hexafluoroantimonate and dibenzyl-4-hydroxyphenylsulfonium hexafluorophosphate; -substituted benzylsulfonium salts such as hydroxyphenylmethylsulfonium hexafluoroantimonate and p-nitrobenzyl-4-hydroxyphenylmethylsulfonium hexafluoroantimonate;

Examples of benzothiazonium salts include 3-benzylbenzothiazonium hexafluoroantimonate, 3-benzylbenzothiazonium hexafluorophosphate, 3-benzylbenzothiazonium tetrafluoroborate, 3-(p-methoxybenzyl)benzothiazonium hexafluoroantimonate, 3-benzyl-2-methylthiobenzothiazonium hexafluoroantimonate, 3-benzyl-5-chlorobenzothiazonium hexafluoroantimonate, and the like.

Examples of tetrahydrothiophenium salts include 4,7-di-n-butoxy-1-naphthyltetrahydrothiophenium trifluoromethanesulfonate, 4,7-di-n-butoxynaphthyltetrahydrothiophenium-10-camphorsulfonate, and the like. In addition, as the onium salt, the onium salts described in JP-A-2014-174235, JP-A-2016-87486, JP-A-2014-157252, JP-A-2015-18131, etc. can also be used as the acid generator (B).

Specific examples of the oxime sulfonate compound, sulfonimide compound, onium salt, halogen-containing compound, diazomethane compound, sulfone compound, sulfonate ester compound, and carboxylate ester compound include compounds described in paragraphs 0078 to 0106 of JP-A-2014-157252, compounds described in International Publication No. 2016/124493, and the like. As the acid generator (B), a compound known as an ionic photoacid-generating type or nonionic photoacid-generating type cationic polymerization initiator can also be used. Among these, from the viewpoint of radiation sensitivity, at least one selected from the group consisting of oxime sulfonate compounds, sulfonimide compounds and onium salts can be preferably used as the acid generator (B).

In the present composition, the content of the acid generator (B) is preferably 0.5 parts by mass or more, more preferably 1 part by mass or more, and even more preferably 2 parts by mass or more, relative to 100 parts by mass of the polymer (A). The content of the acid generator (B) is preferably 30 parts by mass or less, more preferably 20 parts by mass or less, and even more preferably 10 parts by mass or less, relative to 100 parts by mass of the polymer (A). When the content of the acid generator (B) is 0.5 parts by mass or more, sufficient acid is generated by irradiation with radiation, and the difference in solubility in an alkaline developer between the irradiated portion and the non-irradiated portion can be sufficiently increased. Thereby, favorable patterning can be performed. Also, the amount of acid participating in the reaction with the polymer (A) can be increased in the step (V), and a lens with excellent heat resistance and chemical resistance can be obtained. On the other hand, when the content of the acid generator (B) is 30 parts by mass or less, the amount of the unreacted acid generator (B) in the radiation-irradiated portion can be sufficiently reduced during the development process, and deterioration in developability due to the remaining acid generator (B) can be suppressed.

<Solvent (C)>
The present composition is a liquid composition in which the polymer (A), the acid generator (B), and other optional ingredients are preferably dissolved or dispersed in the solvent (C). As the solvent (C), an organic solvent that dissolves each component blended in the present composition and that does not react with each component is preferred.

Specific examples of the solvent (C) include alcohols such as methanol, ethanol, isopropanol, butanol, and octanol; Ethers such as methylene glycol dimethyl ether, diethylene glycol dimethyl ether, diethylene glycol ethyl methyl ether; Amides such as dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone; Ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone; Aromatic hydrocarbons such as benzene, toluene, xylene, ethylbenzene. Among these, the solvent (C) preferably contains at least one selected from the group consisting of ethers and esters, and more preferably at least one selected from the group consisting of ethylene glycol alkyl ether acetate, diethylene glycols, propylene glycol monoalkyl ether, and propylene glycol monoalkyl ether acetate.

<Other ingredients>
In addition to the polymer (A), acid generator (B) and solvent (C) described above, the present composition may further contain components other than these (hereinafter also referred to as "other components"). Other components include a nitrogen-containing basic compound (D), a polyfunctional reactive compound (E), a surfactant, an adhesion aid, and the like.

・ Nitrogen-containing basic compound (D)
The nitrogen-containing basic compound (D) (hereinafter also simply referred to as "basic compound (D)") is blended into the present composition as an acid diffusion control agent that controls the diffusion length of the acid generated from the acid generator (B) upon exposure. By including the nitrogen-containing basic compound (D) in the present composition, the diffusion length of the acid can be appropriately controlled, and the pattern shape can be improved.

As the nitrogen-containing basic compound (D), for example, it can be arbitrarily selected from compounds used as acid diffusion control agents in chemically amplified resists. Specifically, examples of the nitrogen-containing basic compound (D) include fatty acid amines, aromatic amines, heterocyclic amines, quaternary ammonium hydroxides, carboxylic acid quaternary ammonium salts, and the like. Specific examples of the nitrogen-containing basic compound (D) include compounds described in paragraphs 0128 to 0147 of JP-A-2011-232632. At least one selected from the group consisting of aromatic amines and heterocyclic amines can be preferably used as the nitrogen-containing basic compound (D).

Examples of aromatic amines and heterocyclic amines include aniline, N-methylaniline, N-ethylaniline, N-propylaniline, N,N-dimethylaniline, 2-methylaniline, 3-methylaniline, 4-methylaniline, ethylaniline, propylaniline, trimethylaniline, 2-nitroaniline, 3-nitroaniline, 4-nitroaniline, 2,4-dinitroaniline, 2,6-dinitroaniline, 3,5-dinitroaniline, N, Aniline derivatives such as N-dimethyltoluidine; imidazole, 4-methylimidazole, 4-methyl-2-phenylimidazole, benzimidazole, 2-phenylbenzimidazole, triphenylimidazole, Nt-butoxycarbonyl-2-phenylbenzimidazole derivatives; pyrrole, 2H-pyrrole, 1-methylpyrrole, 2,4-dimethylpyrrole, 2,5-dimethylpyrrole, N-methylpyrrole Pyrrole derivatives such as; Lysine, 1-methyl-2-pyridone, 4-pyrrolidinopyridine, 1-methyl-4-phenylpyridine, 2-(1-ethylpropyl)pyridine, aminopyridine, dimethylaminopyridine, pyridine derivatives such as nicotine; morpholine derivatives such as N-acetylmorpholine, and compounds described in JP-A-2011-232632.

When the composition contains the nitrogen-containing basic compound (D), the content ratio thereof is preferably 0.005 parts by mass or more, more preferably 0.01 part by mass or more, relative to 100 parts by mass of the polymer (A), from the viewpoint of sufficiently improving the pattern forming ability of the composition by blending the nitrogen-containing basic compound (D). The content of the nitrogen-containing basic compound (D) is preferably 10 parts by mass or less, more preferably 5 parts by mass or less, relative to 100 parts by mass of the polymer (A).

- Polyfunctional reactive compound (E)
The polyfunctional reactive compound (E) (hereinafter also simply referred to as "reactive compound (E)") is a compound having two or more functional groups capable of reacting with the polymer (A) upon stimulation (preferably heat). By further including the reactive compound (E) in the present composition, the flow margin can be widened, and the chemical resistance of the obtained cured product can be further improved. Note that the reactive compound (E) is a component different from the polymer (A).

The functional group possessed by the reactive compound (E) is preferably a group that reacts with the functional group possessed by the polymer (A) upon application of heat to form a crosslinked structure. Examples of the functional group possessed by the reactive compound (E) include an oxiranyl group, an oxetanyl group, a (meth)acryloyl group, a formyl group, an acetyl group, a vinyl group, an isopropenyl group, an alkoxymethyl group, a methylol group, etc., and can be appropriately selected according to the functional group possessed by the polymer (A). As the reactive compound (E), at least one compound selected from the group consisting of polyfunctional oxirane compounds, polyfunctional oxetane compounds, polyfunctional melamine compounds and polyfunctional alkoxymethyl compounds can be preferably used because of its high thermal reactivity with the carboxy groups or hydroxyl groups in the polymer (A).

Specific examples of the reactive compound (E) include bisphenol polyglycidyl ethers such as bisphenol A diglycidyl ether, bisphenol F diglycidyl ether, bisphenol S diglycidyl ether, hydrogenated bisphenol A diglycidyl ether, hydrogenated bisphenol F diglycidyl ether, and hydrogenated bisphenol AD diglycidyl ether; polyglycidyl ethers of polyhydric alcohols such as phosphorus triglycidyl ether, trimethylolpropane triglycidyl ether, polyethylene glycol diglycidyl ether and polypropylene glycol diglycidyl ether; aliphatic polyglycidyl ethers of polyether polyols obtained by adding one or more alkylene oxides to aliphatic polyhydric alcohols such as ethylene glycol, propylene glycol and glycerin; compounds having two or more 3,4-epoxycyclohexyl groups in the molecule, such as -epoxycyclohexyl-5,5-spiro-3,4-epoxy)cyclohexane-meta-dioxane; are mentioned.

　As polyfunctional oxetane compounds, 3,7-bis(3-oxetanyl)-5-oxa-nonane, 1,4-bis[(3-ethyl-3-oxetanylmethoxy)methyl]benzene, 1,2-bis[(3-ethyl-3-oxetanylmethoxy)methyl]ethane, 1,3-bis[(3-ethyl-3-oxetanylmethoxy)methyl]propane, bis[1-ethyl(3-oxetanyl) ] methyl ether, bis(3-ethyl-3-oxetanylmethyl) ether, ethylene glycol bis(3-ethyl-3-oxetanylmethyl) ether, triethylene glycol bis(3-ethyl-3-oxetanylmethyl) ether, tetraethylene glycol bis(3-ethyl-3-oxetanylmethyl) ether, 1,3-bis(3-ethyl-3-oxetanylmethoxy)propane, 1,4-bis(3-ethyl-3-oxetanylmethoxy)butane , 1,4-bis(3-ethyl-3-oxetanylmethoxymethyl)benzene, 1,3-bis(3-ethyl-3-oxetanylmethoxymethyl)benzene, 1,2-bis(3-ethyl-3-oxetanylmethoxymethyl)benzene, 4,4'-bis[(3-ethyl-3-oxetanyl)methoxymethyl]biphenyl, 2,2'-bis(3-ethyl-3-oxetanylmethoxymethyl)biphenyl, 1,6-bis( (3-methyloxetan-3-yl)methoxy)hexane, 1,6-bis((3-ethyloxetan-3-yl)methoxy)hexane, 3-ethyl-3{[(3-ethyloxetan-3-yl)methoxy]methyl}oxetane and the like.

Examples of polyfunctional melamine compounds include hexamethoxymethylmelamine (2,4,6-tris[bis(methoxymethyl)amino]-1,3,5-triazine), hexaethoxymethylmelamine, hexapropoxymethylmelamine, hexabutoxymethylmelamine, and hexapentyloxymethylmelamine.

Examples of polyfunctional alkoxymethyl compounds include reaction products of polyhydric phenol compounds and formaldehyde. Specific examples of polyfunctional phenol compounds include 4-(1-{4-[1,1-bis(4-hydroxyphenyl)ethyl]phenyl}-1-methylethyl)phenol, 1,1,1-tris(4-hydroxyphenyl)ethane, and 4,4'-dihydroxybiphenyl. Commercially available polyfunctional alkoxymethyl compounds include HMOM-TPHAP (manufactured by Honshu Chemical Co., Ltd.), Nicalac Mw-100LM, Nicalac Mx-750LM, Nicalac Mx-270, and Nicalac Mx-280 (manufactured by Sanwa Chemical Co., Ltd.).

When the reactive compound (E) is blended in the composition, the content of the reactive compound (E) is preferably 0.05 parts by mass or more, more preferably 0.1 parts by mass or more, with respect to 100 parts by mass of the total amount of the polymer (A) contained in the composition, from the viewpoint of ensuring a wide flow margin. In addition, from the viewpoint of suppressing a decrease in sensitivity and from the viewpoint of obtaining a microlens having a favorable pattern shape by sufficiently generating an acid in the exposed area by the radiation irradiation in the step (II), the content of the reactive compound (E) is preferably 5 parts by mass or less, more preferably 4 parts by mass or less, more preferably 2 parts by mass or less with respect to 100 parts by mass of the total amount of the polymer (A) contained in the present composition.

-Surfactant A surfactant can be used to improve the applicability of the present composition (reduction of spreadability and uneven application). Examples of surfactants include fluorine-based surfactants, silicone-based surfactants, and nonionic surfactants.

Specific examples of surfactants include the following trade names as fluorosurfactants: Megafac F-171, F-172, F-173, F-251, F-430, F-554, F-563 (manufactured by DIC); Florard FC430, FC431 (manufactured by Sumitomo 3M); 101, SC-102, SC-103, SC-104, SC-105, SC-106, S-611 (manufactured by AGC Seimi Chemical Co., Ltd.); 75, same No. 95 (manufactured by Kyoeisha Chemical Co., Ltd.); FTX-218 (manufactured by Neos); F-top EF301, EF303 and EF352 (manufactured by Shin-Akita Kasei).

The following product names of silicone-based surfactants include SH200-100cs, SH-28PA, SH-30PA, SH-89PA, SH-190, SH-8400, FLUID, SH-193, SZ-6032, SF-8428, DC-57, DC-190, PAINTAD19, FZ-2101, FZ-77 , FZ-2118, L-7001, L-7002 (manufactured by Dow Corning Toray Silicone Co., Ltd.); organosiloxane polymer KP341 (manufactured by Shin-Etsu Chemical Co., Ltd.);

Examples of nonionic surfactants include polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl ether, polyoxyethylene n-octylphenyl ether, polyoxyethylene n-nonylphenyl ether, polyethylene glycol dilaurate, and polyethylene glycol distearate.

When a surfactant is blended in the composition, the content of the surfactant is preferably 0.01 to 1.5 parts by mass, more preferably 0.02 to 1.2 parts by mass, and even more preferably 0.05 to 1.0 parts by mass with respect to 100 parts by mass of the total amount of the polymer (A) contained in the composition.

- Adhesion aid The adhesion aid is a component that improves the adhesion between the cured product formed using the present composition and the substrate. A functional silane coupling agent having a reactive functional group can be preferably used as the adhesion aid. A carboxy group, a (meth)acryloyl group, an epoxy group, a vinyl group, an isocyanate group etc. are mentioned as a reactive functional group which a functional silane coupling agent has.

Specific examples of functional coupling agents include trimethoxysilylbenzoic acid, 3-glycidyloxypropyltrimethoxysilane, 3-glycidyloxypropyltriethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-(meth)acryloxypropyltrimethoxysilane, 3-(meth)acryloxypropyltriethoxysilane, vinyltriacetoxysilane, vinyltrimethoxysilane, and 3-isocyanatopropyltriethoxysilane. be done.

When the composition contains an adhesion aid, the content is preferably 0.01 parts by mass or more and 4 parts by mass or less, more preferably 0.1 parts by mass or more and 2 parts by mass or less with respect to 100 parts by mass of the polymer (A) contained in the composition.

・About the epoxy group-containing compound It is preferable that the present composition does not contain a compound having an oxiranyl group or an oxetanyl group (hereinafter also referred to as an "epoxy group-containing compound") as another component, or if it contains an epoxy group-containing compound, the content is relatively small. As a result, sufficient acid can be generated in the exposed area by irradiation with radiation in step (II), and a cured product having a favorable pattern shape can be obtained by the subsequent development treatment, exposure treatment and heat treatment.

Epoxy group-containing compounds include monofunctional compounds and polyfunctional compounds. Examples of monofunctional compounds include compounds having an epoxy group among the compounds exemplified as adhesion promoters. Examples of the polyfunctional compound include the compounds exemplified as the polyfunctional oxirane compound and the polyfunctional oxetane compound in the description of the polyfunctional reactive compound (E).

The content of the epoxy group-containing compound in the composition is preferably 0% by mass or more and 5% by mass or less, more preferably 0% by mass or more and 4% by mass or less, still more preferably 0% by mass or more and 2% by mass or less, and even more preferably 0% by mass or more and 1% by mass or less. When the content of the epoxy group-containing compound is within the above range, sufficient acid can be generated in the exposed area by the radiation irradiation in step (II), and a microlens having a favorable pattern shape can be formed.

In addition to the above, other components include, for example, antioxidants, sensitizers, photodegradable bases, softeners, plasticizers, reaction initiators (photoradical polymerization initiators, etc.), polymerization inhibitors, chain transfer agents, and the like. The mixing ratio of these components is appropriately selected according to each component within a range that does not impair the effects of the present disclosure.

The composition can be obtained by mixing the polymer (A), the acid generator (B), the solvent (C), and optionally other ingredients in a predetermined ratio. A composition obtained by mixing each component may be filtered through a filter having a pore size of 0.5 μm or less, for example.

The solid content concentration of the present composition (that is, the ratio of the total mass of components other than the solvent (C) in the radiation-sensitive composition to the total mass of the radiation-sensitive composition) is appropriately selected in consideration of viscosity, volatility, etc., but is preferably in the range of 1 to 60% by mass. A solid content concentration of 1% by mass or more is preferable in that a sufficient film thickness can be ensured when the present composition is applied onto a substrate. Further, when the solid content concentration is 60% by mass or less, the film thickness of the coating film does not become excessively large, and the viscosity of the present composition can be increased appropriately, which is preferable in terms of ensuring good coatability. The solid content concentration in the present composition is more preferably 2 to 50% by mass, still more preferably 5 to 40% by mass.

[Lens manufacturing method]
A microlens can be produced by applying a thermal flow method using the radiation-sensitive composition prepared as described above. The present composition is particularly suitable as a positive pattern-forming material for forming a pattern into a microlens using an alkaline developer. Each step (steps (I) to (V)) included in the microlens manufacturing method of the present disclosure will be described below.

<Step (I): Coating step>
Step (I) is a step of forming a coating film on a substrate by applying the present composition onto the substrate. Examples of the base material include glass substrates, silicon wafers, plastic substrates, and substrates having colored resists, overcoats, antireflection films, and various metal thin films formed thereon. Examples of plastic substrates include resin substrates made of plastics such as polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyethersulfone, polycarbonate, and polyimide. Various elements (for example, light-receiving elements such as photodiodes and light-emitting elements such as organic light-emitting diodes) may be provided in advance on these substrates.

As a method for applying the present composition, for example, an appropriate method such as a spray method, a roll coating method, a spin coating method (spin coating method), a slit die coating method, a bar coating method, an inkjet method, or the like can be adopted. Among these, the spin coating method, the bar coating method, or the slit die coating method is preferable as the coating method.

After coating the composition on the substrate, the composition may be preheated (pre-baking) for the purpose of preventing dripping. The pre-baking conditions may be, for example, 60 to 130.degree. The film thickness of the formed coating film after prebaking is preferably 0.1 to 8 μm, more preferably 0.2 to 5 μm, and even more preferably 0.4 to 3 μm.

<Step (II): First Exposure Step>
Step (II) is a step of irradiating a portion of the coating film formed in step (I) with radiation to generate acid in the exposed area. In step (II), irradiation of the coating film is performed through a mask having a pattern (for example, a dot pattern) to obtain microlenses having a desired shape. The mask may be a multi-tone mask such as a halftone mask or a graytone mask.

The radiation to be applied to the coating film includes, for example, ultraviolet rays, far ultraviolet rays, X-rays, charged particle beams, and the like. Examples of ultraviolet rays include g-line (wavelength: 436 nm), i-line (wavelength: 365 nm), KrF excimer laser light (wavelength: 248 nm), and the like. X-rays include synchrotron radiation and the like. An electron beam etc. are mentioned as a charged particle beam. Among these, the radiation irradiated to the coating film is preferably ultraviolet rays, and more preferably ultraviolet rays having a wavelength of 200 nm or more and 380 nm or less. Examples of light sources to be used include low-pressure mercury lamps, high-pressure mercury lamps, deuterium lamps, metal halide lamps, argon resonance lamps, xenon lamps, excimer lasers, and the like. The exposure dose of radiation is preferably 1,000 J/m ² to 20,000 J/m ² .

In the production method of the present disclosure, after the exposure in step (II), post-exposure baking (PEB) may be performed for the purpose of promoting deprotection of the acid-labile groups possessed by the polymer (A). The temperature of the PEB is, for example, 60-130°C, preferably 70-120°C.

<Step (III): Development step>
Step (III) is a step of forming a pattern on the substrate by developing the coating film irradiated with radiation in step (II). By this development step, the exposed portion of the coating film formed on the substrate is removed, and a pattern consisting of the unexposed portion can be formed on the substrate.

Examples of developing solutions include sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, ammonia, ethylamine, n-propylamine, diethylamine, diethylaminoethanol, di-n-propylamine, triethylamine, methyldiethylamine, dimethylethanolamine, triethanolamine, tetramethylammonium hydroxide (TMAH), tetraethylammonium hydroxide, pyrrole, piperidine, 1,8-diazabicyclo[5.4.0]-7-undecene, 1,5-diaza An aqueous solution of an alkali (basic compound) such as bicyclo[4.3.0]-5-nonane can be used. Further, an aqueous solution obtained by adding an appropriate amount of a water-soluble organic solvent such as methanol or ethanol or a surfactant to an alkaline aqueous solution, or by adding a small amount of various organic solvents capable of dissolving the present composition, may be used as a developer.

As a developing method, for example, an appropriate method such as a liquid heaping method, a dipping method, a swinging immersion method, a shower method, or the like can be adopted. The development time may be appropriately adjusted according to the composition of the present composition, and may be, for example, 30 seconds to 120 seconds.

<Step (IV): Second exposure step>
Step (IV) is a step of further irradiating at least part of the developed coating film with radiation. Irradiation with radiation in step (IV) (hereinafter also referred to as “post-exposure”) is preferably performed on the entire surface of the coating film after development (that is, the unexposed area in step (II)). Since the acid generator (B) remains in the pattern, post-exposure to generate acid in the pattern and further heating in the next step (V) are thought to allow the acid to function as a cross-linking catalyst and allow the cross-linking reaction to proceed. As for the type of radiation and exposure conditions in post-exposure, the same conditions as in step (II) can be employed. The conditions such as the wavelength of the irradiation light, the irradiation amount, and the light source in the post-exposure may be the same as or different from those in step (II).

<Step (V): Heating step>
Step (V) is a step of heating the pattern after post-exposure. By the heat treatment in step (V), the composition is cured while thermally flowing the pattern (for example, a pattern having a substantially rectangular cross section) obtained in steps (I) to (IV). As a result, a microlens array in which hemispherical fine cured products are regularly arranged on the substrate can be obtained. Heat treatment can be performed, for example, using a heating device such as an oven or a hot plate.

The heating temperature in step (V) is preferably 80°C or higher, more preferably 100°C or higher, still more preferably 120°C or higher, and even more preferably 140°C or higher, from the viewpoint of obtaining microlenses with high heat resistance and chemical resistance and good shape. Moreover, the heating temperature in step (V) is preferably 240° C. or lower, more preferably 220° C. or lower, and even more preferably 200° C. or lower. The heating time can be appropriately set according to the type of heating device and the like. For example, when heating is performed using a hot plate, the heating time is, for example, 5 to 30 minutes. Moreover, when heating is performed in an oven, the heating time is, for example, 10 to 90 minutes. In step (V), a step baking method in which heat treatment is performed multiple times can also be used.

The microlens obtained in this way has a good lens shape. The diameter of the microlens is, for example, 1 μm or more and 100 μm or less. Further, the microlens obtained from the present composition has excellent chemical resistance and high transparency. Therefore, the microlens of the present disclosure can be suitably used as a microlens for a solid-state imaging device included in an imaging device such as a camera, or for various display devices such as an organic EL device and a liquid crystal display device provided in various display devices.

According to the present disclosure shown above, the following means are provided.

[Means 1] A radiation-sensitive composition for manufacturing lenses, comprising a polymer (A), a radiation-sensitive acid generator (B), and a solvent (C), wherein the polymer (A) contains, in the same molecule or in different molecules, a structural unit (a1) having a hydroxyl group bonded to an aromatic ring and a structural unit (a2) in which an acid-dissociable group is eliminated by the action of an acid to generate a carboxy group.
[Means 2] The radiation-sensitive composition for manufacturing lenses according to [Means 1], wherein the total content of the structural unit (a1) and the structural unit (a2) is 50 mol% or more relative to the total structural units constituting the polymer (A).
[Means 3] The radiation-sensitive composition for manufacturing lenses according to [Means 1] or [Means 2], wherein the structural unit (a1) is a structural unit derived from at least one selected from the group consisting of the compound represented by the above formula (a1-1) and the compound represented by the above formula (a1-2).
[Means 4] The radiation-sensitive composition for producing lenses according to any one of [Means 1] to [Method 3], wherein the structural unit (a2) is a structural unit derived from at least one selected from the group consisting of the compound represented by the formula (a2-1) and the compound represented by the formula (a2-2).
[Means 5] The radiation-sensitive composition for manufacturing lenses according to any one of [Means 1] to [Means 4], wherein the content of the structural unit (a3) having an oxiranyl group or an oxetanyl group in the polymer (A) is 0 mol% or more and 15 mol% or less with respect to the total structural units constituting the polymer (A).
[Means 6] The radiation-sensitive composition for manufacturing lenses according to any one of [Means 1] to [Means 5], further comprising a nitrogen-containing basic compound (D).
[Means 7] The radiation-sensitive composition for manufacturing lenses according to any one of [Means 1] to [Means 6], wherein the polyfunctional reactive compound (excluding the polymer (A)) is contained in an amount of 5 parts by mass or less per 100 parts by mass of the total amount of the polymer (A).
[Means 8] The radiation-sensitive composition for manufacturing lenses according to [Means 7], wherein the polyfunctional reactive compound is at least one selected from the group consisting of polyfunctional oxirane compounds, polyfunctional oxetane compounds, polyfunctional melamine compounds and polyfunctional alkoxymethyl compounds.
[Means 9] applying the radiation-sensitive composition according to any one of [Means 1] to [Means 8] on a substrate to form a coating film; irradiating a part of the coating film with radiation to generate an acid in an exposed portion; developing the radiation-irradiated coating film to form a pattern on the substrate; irradiating the pattern with radiation; methods of manufacturing lenses, including;
[Means 10] A lens formed using the radiation-sensitive composition according to any one of [Means 1] to [Means 8].
[Means 11] An imaging device comprising the lens according to [Means 10].
[Means 12] An imaging device comprising the imaging device according to [Means 11].
[Means 13] A display device comprising the lens according to [Means 10].
[Means 14] A display device comprising the display element according to [Means 13].

The present disclosure will be specifically described below with reference to examples, but the present disclosure is not limited to these examples. "Parts" and "%" in Examples and Comparative Examples are based on mass unless otherwise specified.

In the examples, the weight average molecular weight (Mw) of the polymer was measured by the following method.
・Measurement method: Gel permeation chromatography (GPC) method ・Apparatus: GPC-101 of Showa Denko Co., Ltd.
・GPC column: Shimadzu GLC GPC-KF-801, GPC-KF-802, GPC-KF-803 and GPC-KF-804 combined ・Mobile phase: Tetrahydrofuran ・Column temperature: 40°C
・Flow rate: 1.0 mL/min ・Sample concentration: 1.0% by mass
・Sample injection volume: 100 μL
・Detector: Differential refractometer ・Standard substance: Monodisperse polystyrene

<Preparation of Radiation-Sensitive Resin Composition>
The polymer (A), acid generator (B), solvent (C), basic compound (D) and reactive compound (E) used to prepare each radiation-sensitive resin composition are shown below.

<<Polymer (A)>>
(A-1): Resin represented by the following formula (A-1) (weight average molecular weight: 10000, x = 55, y = 45)

(A-2): Resin represented by the following formula (A-2) (weight average molecular weight: 12000, x = 45, y = 10, z = 45)

(A-3): Resin represented by the following formula (A-3) (weight average molecular weight: 10000, x = 70, y = 30)

(A-4): Resin represented by the following formula (A-4) (weight average molecular weight 8000, w = 30, x = 30, y = 10, z = 30)

(A-5): Resin represented by the following formula (A-5) (weight average molecular weight: 10000, x = 55, y = 45)

In each of the above formulas representing (A-1) to (A-5), the subscripts (w, x, y, and z) attached to each structural unit are the ratio (mol%) of each structural unit to all structural units constituting each resin.

<<Acid generator (B)>>
(B-1): "SP-606" manufactured by ADEKA
(B-2): triphenylsulfonium trifluoromethanesulfonate

<<Solvent (C)>>
(C-1): propylene glycol monomethyl ether acetate (C-2): propylene glycol monomethyl ether (C-3): methyl 3-methoxypropionate

<<Basic compound (D)>>
(D-1): Nt-butoxycarbonyl-2-phenylbenzimidazole (D-2): N-acetylmorpholine

<<Reactive compound (E)>>
(E-1): 4,4′-bis[(3-ethyl-3-oxetanyl)methoxymethyl]biphenyl (E-2): reaction product of 4-(1-{4-[1,1-bis(4-hydroxyphenyl)ethyl]phenyl}-1-methylethyl)phenol and formaldehyde

[Example 1]
A polymer solution containing 100 parts by mass (solid content) of (A-1) as the polymer (A), 4 parts by mass of (B-1) as the acid generator (B), 0.8 parts by mass of (D-1) as the basic compound (D), 0.5 parts by mass of the adhesion aid (3-glycidyloxypropyltrimethoxysilane), and 0.2 parts by mass of the surfactant ("FTX-218" manufactured by Neos) were mixed, and the solid content concentration was 12 mass parts. %, and then dissolved by stirring after adding (C-1) as solvent (C). Next, the radiation-sensitive resin composition of Example 1 was prepared by filtering the mixture through a membrane filter with a pore size of 0.2 µm.

[Examples 2-8 and Comparative Examples 1-2]
Radiation-sensitive resin compositions of Examples 2 to 8 and Comparative Examples 1 and 2 were prepared in the same manner as in Example 1 except that the types and blending amounts (parts by mass) of the polymer (A), acid generator (B), solvent (C), basic compound (D) and reactive compound (E) were as shown in Table 1. In addition, in Table 1, the blending amount of the polymer (A) is 100 parts by mass. The numerical values of the acid generator (B), the basic compound (D) and the reactive compound (E) indicate the compounding ratio (parts by mass) of each compound with respect to 100 parts by mass of the polymer (A) used in the preparation of each radiation-sensitive resin composition. The numerical value of the solvent (C) represents the ratio (% by mass) of each compound to the total amount of solvent used in the preparation of each radiation-sensitive resin composition.

<Evaluation>
Each radiation-sensitive resin composition was evaluated according to the following evaluation method. Table 2 shows the evaluation results.

〔sensitivity〕
Each of the radiation-sensitive resin compositions of Examples 1 to 8 and Comparative Examples 1 and 2 was applied onto a silicon substrate having an antireflection film formed thereon using a clean track. Then, it was pre-baked at 90° C. for 90 seconds to form a coating film having a thickness of 0.6 μm. Then, using a reduction projection exposure machine (NA=0.55, λ=248 nm) manufactured by Nikon Corporation "NSR2205EX12B", the coating film was exposed through a mask having a pattern of 0.2 μm spaces and 0.9 μm dots while varying the exposure time. After the exposure, the substrate was subjected to PEB treatment on a hot plate at 90° C. for 90 seconds, and then developed using an aqueous tetramethylammonium hydroxide solution (developer) at 25° C. for 1 minute by the liquid swell method. After development, the coating was rinsed with water and dried to form a pattern on the wafer. Sensitivity (mJ/cm ² ) was defined as the minimum amount of exposure required to form a 0.2 µm space and a 0.9 µm dot in such exposure and development processing. Under these conditions, a sensitivity of 100 mJ/cm ² or less was evaluated as “⊚”, a sensitivity of more than 100 mJ/cm ² and less than 130 mJ/cm ² was evaluated as “◯”, and a sensitivity of 130 mJ/cm ² or more was evaluated as “X”.

[Flowability]
For Examples 1 to 8 and Comparative Examples 1 and 2, the 0.2 μm space/0.9 μm dot pattern formed in the above sensitivity evaluation was further exposed using Canon's “PLA-501F” exposure machine (ultra-high pressure mercury lamp) so that the cumulative irradiation dose was 500 mJ/cm ² . Next, using a hot plate, post-baking treatment was performed at each temperature of 130° C. to 220° C. for 300 seconds, and the cross section of the resist pattern was observed by SEM. The minimum temperature T1 at which an appropriate microlens pattern is formed without the bottom portions of adjacent microlens patterns coming into contact with each other and the minimum temperature T2 at which the bottom portions of adjacent microlens patterns come into contact with each other by the post-baking process were determined. The temperature difference (T2-T1) between the lowest temperatures T1 and T2 was defined as the flow margin, and evaluation was made according to the following criteria. Under these conditions, a flow margin of 10° C. or more was evaluated as “⊚”, a flow margin of less than 10° C. of 5° C. or more was evaluated of “◯”, and a flow margin of less than 5° C. was evaluated of “×”.

〔chemical resistance〕
Using a spinner, each of the radiation-sensitive resin compositions of Examples 1 to 8 and Comparative Examples 1 and 2 was applied onto a silicon substrate, and then prebaked on a hot plate at 90° C. for 90 seconds to form a coating film having a thickness of 0.6 μm. The resulting coating film was irradiated with ultraviolet rays from a mercury lamp so that the cumulative irradiation dose was 500 mJ/cm ² . Then, the silicon substrate on which this coating film was formed was post-baked at 180° C. for 300 seconds using a hot plate to obtain a cured film. The film thickness (H1 [μm]) of the obtained cured film was measured. Subsequently, the silicon substrate on which this cured film was formed was immersed in acetone for 5 minutes. The film thickness (H2 [μm]) of the cured film after immersion in acetone was measured, and the film thickness change rate was calculated from the following formula and used as an index of chemical resistance.
Film thickness change rate = {(H2-H1)/H1} x 100 (%)
According to the above formula, the absolute value of the film thickness change rate was judged to be "O" when the absolute value was less than 5.0%, and was judged to be "X" when it was 5.0% or more.

〔transparency〕
A cured film was prepared using the same method as for chemical resistance evaluation, except that a glass substrate was used. The transmittance of the obtained cured film was measured using an ultraviolet-visible spectrophotometer ("V-630" manufactured by JASCO Corporation). At this time, when the transmittance of light having a wavelength of 400 nm was 97% or more, it was judged as "⊚", when it was 95% or more and less than 97%, it was judged as "◯", and when it was less than 95%, it was judged as "x".

As shown in Table 2, the radiation-sensitive resin compositions of Examples 1-8 exhibited good radiation sensitivity, and also had good flow properties, chemical resistance and transparency. On the other hand, the radiation-sensitive resin composition of Comparative Example 1, which has the same composition as in Example 1 except that the polymer (A-5) having a protected hydroxyl group was used instead of the polymer (A-1) having a protected carboxyl group, was evaluated as "x" in flowability and chemical resistance. Further, the radiation sensitive resin composition of Comparative Example 2, in which (E-1) as the reactive compound (E) was added to the radiation sensitive resin composition of Comparative Example 1 by 6 parts by mass based on 100 parts by mass of the polymer (A-5), was evaluated as "x" in radiation sensitivity, although the flow property and chemical resistance were improved.

From the above results, it has been clarified that the radiation-sensitive composition containing the polymer (A) containing the structural unit (a1) and the structural unit (a2) exhibits high radiation sensitivity, can ensure a wide flow margin, and can exhibit various properties required for a radiation-sensitive composition for microlens production in a well-balanced manner, such as good chemical resistance and transparency of the resulting cured product.

Claims (21)

1. A step of applying a radiation-sensitive composition onto a substrate to form a coating film;
   A step of irradiating a portion of the coating film with radiation to generate acid in the exposed portion;
   forming a pattern on the base material by developing the coating film irradiated with the radiation;
   irradiating the pattern with radiation;
   forming a lens on the substrate by heating the pattern after irradiating the pattern with radiation;
   including
   The radiation-sensitive composition contains a polymer (A), a radiation-sensitive acid generator (B), and a solvent (C),
   The polymer (A) comprises a structural unit (a1) having a hydroxyl group bonded to an aromatic ring, and a structural unit (a2) that produces a carboxyl group by elimination of an acid-dissociable group by the action of an acid, in the same molecule or in different molecules.
   How the lens is made.
2. The method for producing a lens according to claim 1, wherein the total content of the structural unit (a1) and the structural unit (a2) is 50 mol% or more with respect to the total structural units constituting the polymer (A).
3. The method for producing a lens according to claim 1 or 2, wherein the structural unit (a1) is a structural unit derived from at least one selected from the group consisting of a compound represented by the following formula (a1-1) and a compound represented by the following formula (a1-2).
   

   

   （式（ａ１－１）中、Ｒ ^１は、水素原子、ハロゲン原子、炭素数１～４のアルキル基又は炭素数１～４のフッ素化アルキル基である。Ｒ ^２は、単結合、＊ ^１ －Ｃ（＝Ｏ）－Ｏ－又は＊ ^１ －Ｃ（＝Ｏ）－ＮＨ－である。「＊ ^１ 」は、Ｒ ^１が結合している炭素原子との結合手を表す。Ｒ ^３は、ハロゲン原子、炭素数１～４のアルキル基、炭素数１～４のアルコキシ基又は炭素数１～４のフッ素化アルキル基である。ｍ１は０～４の整数である。ｍ２は１又は２である。ただし、ｍ１＋ｍ２≦５である。ｍ１が２以上の場合、複数のＲ ^３は同一又は異なる。
   In formula (a1-2), R ⁴ is a halogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms or a fluorinated alkyl group having 1 to 4 carbon atoms. n1 is an integer of 0-4. n2 is 1 or 2; However, it is n1+n2<=5. When n1 is 2 or more, multiple ^R4 are the same or different. )
4. The method for producing a lens according to claim 1 or 2, wherein the structural unit (a2) is a structural unit derived from at least one selected from the group consisting of a compound represented by the following formula (a2-1) and a compound represented by the following formula (a2-2).
   

   

   （式（ａ２－１）中、Ｒ ^５は、水素原子、ハロゲン原子、炭素数１～４のアルキル基又は炭素数１～４のフッ素化アルキル基である。Ｒ ^６は、単結合、置換若しくは無置換のフェニレン基、又は＊ ^２ －Ｃ（＝Ｏ）－Ｏ－Ｒ ^１５ －である。「＊ ^２ 」は、Ｒ ^５が結合している炭素原子との結合手を表す。Ｒ ^１５は置換若しくは無置換の２価の炭化水素基である。Ｒ ^７は１価の脂肪族炭化水素基である。Ｒ ^８及びＲ ^９は、それぞれ独立して、１価の脂肪族炭化水素基であるか、又はＲ ^８及びＲ ^９が互いに合わせられてＲ ^８及びＲ ^９が結合する炭素原子と共に構成される脂環式構造を表す。
   In formula (a2-2), R ¹⁰ is a hydrogen atom, a halogen atom, an alkyl group having 1 to 4 carbon atoms, or a fluorinated alkyl group having 1 to 4 carbon atoms. R ¹¹ is a single bond, a substituted or unsubstituted phenylene group, or * ³ -C(=O)-OR ¹⁶ -. "* ³ " represents a bond with the carbon atom to which ^R10 is bonded. R ¹⁶ is a substituted or unsubstituted divalent hydrocarbon group. ^R12 is a hydrogen atom or a monovalent aliphatic hydrocarbon group. R ¹³ and R ¹⁴ represent a cyclic ether structure in which R ¹³ is a monovalent aliphatic hydrocarbon group and R ¹⁴ is a monovalent aliphatic hydrocarbon group, an aralkyl group, or a substituted aralkyl group, or R ¹³ and R ¹⁴ are combined with each other and formed together with the carbon atom to which R ¹³ is attached and the oxygen atom to which R ¹⁴ is attached. )
5. The method for producing a lens according to claim 1 or 2, wherein the content of the structural unit (a3) having an oxiranyl group or an oxetanyl group in the polymer (A) is 0 mol% or more and 15 mol% or less with respect to the total structural units constituting the polymer (A).
6. The method for manufacturing a lens according to claim 1 or 2, wherein the radiation-sensitive composition further contains a nitrogen-containing basic compound (D).
7. The method for producing a lens according to claim 1 or 2, wherein the radiation-sensitive composition contains the polyfunctional reactive compound (E) (excluding the polymer (A)) in a proportion of 5 parts by mass or less with respect to 100 parts by mass of the total amount of the polymer (A).
8. The method for producing a lens according to claim 7, wherein the polyfunctional reactive compound (E) is at least one selected from the group consisting of a polyfunctional oxirane compound, a polyfunctional oxetane compound, a polyfunctional melamine compound and a polyfunctional alkoxymethyl compound.
9. a polymer (A);
   a radiation-sensitive acid generator (B);
   containing a solvent (C),
   The polymer (A) comprises a structural unit (a1) having a hydroxyl group bonded to an aromatic ring and a structural unit (a2) in which an acid-dissociable group is eliminated by the action of an acid to generate a carboxy group, in the same molecule or in different molecules. A radiation-sensitive composition for manufacturing lenses.
10. The radiation-sensitive composition for manufacturing lenses according to claim 9, wherein the total content of the structural unit (a1) and the structural unit (a2) is 50 mol% or more relative to the total structural units constituting the polymer (A).
11. The radiation-sensitive composition for lens manufacturing according to claim 9, wherein the structural unit (a1) is a structural unit derived from at least one selected from the group consisting of a compound represented by the following formula (a1-1) and a compound represented by the following formula (a1-2).
    

    

    （式（ａ１－１）中、Ｒ ^１は、水素原子、ハロゲン原子、炭素数１～４のアルキル基又は炭素数１～４のフッ素化アルキル基である。Ｒ ^２は、単結合、＊ ^１ －Ｃ（＝Ｏ）－Ｏ－又は＊ ^１ －Ｃ（＝Ｏ）－ＮＨ－である。「＊ ^１ 」は、Ｒ ^１が結合している炭素原子との結合手を表す。Ｒ ^３は、ハロゲン原子、炭素数１～４のアルキル基、炭素数１～４のアルコキシ基又は炭素数１～４のフッ素化アルキル基である。ｍ１は０～４の整数である。ｍ２は１又は２である。ただし、ｍ１＋ｍ２≦５である。ｍ１が２以上の場合、複数のＲ ^３は同一又は異なる。
    In formula (a1-2), R ⁴ is a halogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms or a fluorinated alkyl group having 1 to 4 carbon atoms. n1 is an integer of 0-4. n2 is 1 or 2; However, it is n1+n2<=5. When n1 is 2 or more, multiple ^R4 are the same or different. )
12. The radiation-sensitive composition for lens manufacturing according to claim 9, wherein the structural unit (a2) is a structural unit derived from at least one selected from the group consisting of a compound represented by the following formula (a2-1) and a compound represented by the following formula (a2-2).
    

    

    （式（ａ２－１）中、Ｒ ^５は、水素原子、ハロゲン原子、炭素数１～４のアルキル基又は炭素数１～４のフッ素化アルキル基である。Ｒ ^６は、単結合、置換若しくは無置換のフェニレン基、又は＊ ^２ －Ｃ（＝Ｏ）－Ｏ－Ｒ ^１５ －である。「＊ ^２ 」は、Ｒ ^５が結合している炭素原子との結合手を表す。Ｒ ^１５は置換若しくは無置換の２価の炭化水素基である。Ｒ ^７は１価の脂肪族炭化水素基である。Ｒ ^８及びＲ ^９は、それぞれ独立して、１価の脂肪族炭化水素基であるか、又はＲ ^８及びＲ ^９が互いに合わせられてＲ ^８及びＲ ^９が結合する炭素原子と共に構成される脂環式構造を表す。
    In formula (a2-2), R ¹⁰ is a hydrogen atom, a halogen atom, an alkyl group having 1 to 4 carbon atoms or a fluorinated alkyl group having 1 to 4 carbon atoms. R ¹¹ is a single bond, a substituted or unsubstituted phenylene group, or * ³ -C(=O)-OR ¹⁶ -. "* ³ " represents a bond with the carbon atom to which ^R10 is bonded. R ¹⁶ is a substituted or unsubstituted divalent hydrocarbon group. ^R12 is a hydrogen atom or a monovalent aliphatic hydrocarbon group. R ¹³ and R ¹⁴ represent a cyclic ether structure in which R ¹³ is a monovalent aliphatic hydrocarbon group and R ¹⁴ is a monovalent aliphatic hydrocarbon group, an aralkyl group or a substituted aralkyl group, or R ¹³ and R ¹⁴ are combined with each other and composed together with the carbon atom to which R ¹³ is attached and the oxygen atom to which R ¹⁴ is attached. )
13. The radiation-sensitive composition for lens manufacturing according to claim 9, wherein the content of the structural unit (a3) having an oxiranyl group or an oxetanyl group in the polymer (A) is 0 mol% or more and 15 mol% or less with respect to the total structural units constituting the polymer (A).
14. The radiation-sensitive composition for manufacturing lenses according to claim 9, further comprising a nitrogen-containing basic compound (D).
15. The radiation-sensitive composition for manufacturing lenses according to claim 9, wherein the polyfunctional reactive compound (excluding the polymer (A)) is contained in a proportion of 5 parts by mass or less with respect to 100 parts by mass of the total amount of the polymer (A).
16. The radiation-sensitive composition for manufacturing lenses according to claim 15, wherein the polyfunctional reactive compound is at least one selected from the group consisting of polyfunctional oxirane compounds, polyfunctional oxetane compounds, polyfunctional melamine compounds and polyfunctional alkoxymethyl compounds.
17. A lens formed using the radiation-sensitive composition for manufacturing lenses according to any one of claims 9 to 16.
18. An imaging device comprising the lens according to claim 17.
19. An imaging device comprising the imaging element according to claim 18.
20. A display element comprising the lens according to claim 17.
21. A display device comprising the display element according to claim 20.