JP2010134311A - Radiation-sensitive resin composition, interlayer dielectric, microlens, and method of manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a radiation-sensitive resin composition having high sensitivity to radiation, capable of forming an interlayer dielectric having adhesion, high heat resistance, resolution, high transmittance and high reliability, capable of forming a microlens having high transmittance and a good melt figure when the composition is used for forming a microlens, and having excellent storage stability. <P>SOLUTION: The radiation-sensitive resin composition contains (A) a copolymer and (B) a 1,2-quinonediazide compound, wherein the copolymer (A) contains a copolymer produced through a step of polymerizing monomers containing (a1) an unsaturated carboxylic acid and/or an unsaturated carboxylic acid anhydride and (a2) an epoxy group-containing unsaturated compound in the presence of a compound expressed by formula (1). In formula (1), Z<SP>1</SP>and Z<SP>2</SP>each independently represents a benzyl group which may be substituted with an alkyl group having 4 to 18 C. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a radiation-sensitive resin composition, an interlayer insulating film, a microlens, and methods for producing them.

  In an electronic component such as a thin film transistor (hereinafter referred to as “TFT”) type liquid crystal display element, magnetic head element, integrated circuit element, solid-state imaging element, etc., an interlayer insulation is generally used to insulate between wirings arranged in layers. A membrane is provided. As a material for forming the interlayer insulating film, a material having a small number of steps for obtaining a required pattern shape and having sufficient flatness is preferable, and therefore, a radiation sensitive resin composition is widely used (special feature). JP 2001-354822 A and JP 2001-343743 A).

  Among the electronic components, for example, a TFT type liquid crystal display element is manufactured through a process of forming a transparent electrode film on an interlayer insulating film and further forming a liquid crystal alignment film thereon. Therefore, the interlayer insulating film is exposed to a high temperature condition in the transparent electrode film forming process or exposed to a resist stripping solution used for electrode pattern formation, so that it has sufficient heat resistance and solvent resistance. Is required.

In recent years, TFT-type liquid crystal display elements have a tendency to increase screen size, increase brightness, increase definition, increase response speed, reduce thickness, and the like. Therefore, the composition for forming an interlayer insulating film used for the TFT type liquid crystal display element needs to have high sensitivity, and the formed interlayer insulating film has a low dielectric constant, high transmittance, etc. higher than the conventional one. Performance is required.

On the other hand, a microlens having a lens diameter of about 3 to 100 μm or an optical system material of an on-chip color filter such as a facsimile, an electronic copying machine, a solid-state image sensor, or the like is defined as an optical system material. An array of microlenses is used.

To form a microlens or a microlens array, a resist pattern corresponding to the lens is formed and then melt-flowed by heat treatment and used as a lens as it is, or by using the melt-flowed lens pattern as a mask. A method of transferring a lens shape to a base by etching is known. For the formation of the lens pattern, a radiation sensitive resin composition is widely used (see JP-A-6-18702 and JP-A-6-136239).

  By the way, the element on which the microlens or the microlens array as described above is formed is then applied with a planarizing film and an etching resist film in order to remove various insulating films on the bonding pad which is a wiring forming portion. Exposure and development are performed using a desired mask to remove the etching resist in the bonding pad portion, and then the step is performed to remove the planarizing film and various insulating films by etching to expose the bonding pad portion. Therefore, the microlens or the microlens array needs to have solvent resistance and heat resistance in the flattening film and etching resist coating film forming process and the etching process.

  The radiation sensitive resin composition used for forming such a microlens needs to have high sensitivity. In addition, the microlens formed therefrom has a desired radius of curvature, and is required to have high heat resistance, high transmittance, high reliability, and the like.

  Thus, when forming an interlayer insulation film and a micro lens from a radiation sensitive resin composition, the composition needs to be highly sensitive to radiation. In addition, it is required that a patterned thin film showing good adhesion can be easily formed without peeling of the pattern even when the development time exceeds a predetermined time in the development process. The interlayer insulating film formed from the composition is required to have high heat resistance, high solvent resistance, low dielectric constant, high transmittance, high reliability, and the like. On the other hand, when forming a microlens, the microlens is required to have a good melt shape (desired radius of curvature), high heat resistance, high solvent resistance, and high transmittance.

In order to overcome the above problems, Patent Documents 5 and 6 focus on the control of the molecular weight distribution of the copolymer component in the radiation-sensitive resin composition, and employ tetraethylthiuram disulfide and bis (pyrazol-1-yl-thiocarbonyl). ) A copolymer polymerized using a disulfide compound such as disulfide as a molecular weight control agent is disclosed. However, these disulfide compounds have a problem that they are very difficult to handle because they tend to change with time due to decomposition during storage after synthesis.

JP 2001-354822 A JP 2001-343743 A JP-A-6-18702 JP-A-6-136239 International Publication No. 07/029871 Pamphlet JP 2007-126647 A

The present invention has been made in view of these disadvantages in the prior art, and a first object thereof is to easily form a patterned thin film having high sensitivity to radiation and excellent adhesion. High heat resistance, resolution, high transmittance, highly reliable interlayer insulating film can be formed, and when used for forming microlenses, microlenses with high transmittance and good melt shape are formed. It is to provide a radiation sensitive resin composition having excellent storage stability.

A second object of the present invention is to provide a method for forming an interlayer insulating film and a microlens using the radiation sensitive resin composition, and an interlayer insulating film and a microlens formed by the method. .

The first object of the present invention is to
(A) a copolymer, (B) a radiation-sensitive resin composition containing a 1,2-quinonediazide compound, wherein (A) the copolymer is (a1) an unsaturated carboxylic acid and / or an unsaturated carboxylic acid. Radiation sensitivity comprising a copolymer produced by polymerizing an acid anhydride and a monomer containing (a2) an epoxy group-containing unsaturated compound in the presence of a compound represented by the following formula (1) This is achieved by the conductive resin composition.

〔式（１）において、Ｚ^１およびＺ² は相互に独立に炭素数４〜１８のアルキル基または置換されていてもよいベンジル基を示す。〕

In [Equation ^(1), Z 1 and Z ² is an alkyl group or an optionally substituted benzyl group having 4 to 18 carbon atoms independently of one another. ]

By including the specific component (A) copolymer and (B), the radiation-sensitive resin composition can easily form a patterned thin film having high radiation sensitivity and excellent adhesion. it can.

The (A) copolymer is a copolymer produced through a step of living radical polymerization with the compound represented by the formula (1), and has a polystyrene-equivalent weight average molecular weight measured by gel permeation chromatography (GPC). A resin composition comprising a copolymer having (Mw) of 1,000 to 15,000 and a ratio (Mw / Mn) of Mw to polystyrene-converted number average molecular weight (Mn) measured by GPC of 1.8 or less. Depending on the object, good performance such as high radiation sensitivity is exhibited.

The second object of the present invention is achieved by using the above radiation sensitive resin composition for forming an interlayer insulating film or a microlens. The third object of the present invention is achieved by a method of forming an interlayer insulating film or microlens including the following steps, and an interlayer insulating film or microlens formed by such a method.
(1) The process of forming the coating film of this radiation sensitive resin composition on a board | substrate,
(2) A step of irradiating at least a part of the coating film formed in step (1),
(3) A step of developing the coating film irradiated with radiation in the step (2), and (4) A step of heating the coating film developed in the step (3).

The interlayer insulating film and the microlens formed by the above method satisfy all desired characteristics. That is, the interlayer insulating film formed by this method has high heat resistance, resolution, high transmittance, and high reliability, and the microlens formed by this method has high transmittance and good melt shape. Have

The radiation sensitive resin composition of the present invention is excellent in storage stability and has high radiation sensitivity. Further, the interlayer insulating film of the present invention formed from the composition has good adhesion to the substrate, and has excellent heat resistance, high transmittance, and high reliability. Therefore, the interlayer insulating film can be suitably used for electronic parts. Moreover, the microlens of the present invention formed from the composition has good adhesion to the substrate, and has excellent heat resistance, low heat discoloration resistance, solvent resistance, and a good melt shape. Therefore, the microlens can be suitably used as a microlens for a solid-state imaging device.

Hereinafter, each component and other optional components contained in the radiation-sensitive resin composition of the present invention will be described in detail.

I. (A) Copolymer The (A) copolymer in the present invention needs to be soluble in an alkali developer used in the development processing step of the radiation-sensitive resin composition containing the component. A copolymer (hereinafter, referred to as “copolymer [A]”) produced through a polymerization process in the presence of a compound represented by the formula (1) (hereinafter, referred to as “molecular weight control agent”). is there.
As such an alkali-soluble resin, a copolymer of (a1) an unsaturated carboxylic acid and / or an unsaturated carboxylic acid anhydride and another unsaturated compound copolymerizable therewith is preferable. (A1) Unsaturated A copolymer of an unsaturated compound including a carboxylic acid and / or an unsaturated carboxylic acid anhydride and (a2) an epoxy group-containing unsaturated compound is more preferable. The copolymer [A] can be produced by radical polymerization of an unsaturated compound containing the compound (a1) and the compound (a2) in the presence of a polymerization initiator in a solvent. In the production of the copolymer [A], an unsaturated compound other than the above (a1) and (a2) may be radically polymerized as the compound (a3) together with the compound (a1) and the compound (a2). Copolymer [A] is preferably a structural unit derived from compound (a1) based on the sum of repeating units derived from compounds (a1) and (a2) (and optionally compound (a3)). 5 to 40% by weight, particularly preferably 5 to 25% by weight. When the structural unit derived from the compound (a1) in the copolymer [A] is 5 to 40% by weight, various properties such as radiation sensitivity, developability and storage stability of the radiation sensitive resin composition are higher. A radiation sensitive resin composition balanced in level is obtained.

The compound (a1) is an unsaturated carboxylic acid and / or an unsaturated carboxylic acid anhydride having radical polymerizability. Specific examples of the compound (a1) include monocarboxylic acids, dicarboxylic acids, dicarboxylic acid anhydrides, mono [(meth) acryloyloxyalkyl] esters of polyvalent carboxylic acids, and carboxyl groups and hydroxyl groups at both ends. Examples thereof include polymer mono (meth) acrylates, polycyclic compounds having a carboxyl group, and anhydrides thereof.

Specific examples thereof include monocarboxylic acids such as acrylic acid, methacrylic acid, and crotonic acid; dicarboxylic acids such as maleic acid, fumaric acid, citraconic acid, mesaconic acid, itaconic acid, and the like; Anhydrides of compounds exemplified as acids, etc .; mono [(meth) acryloyloxyalkyl] esters of polyvalent carboxylic acids, succinic acid mono [2- (meth) acryloyloxyethyl], phthalic acid mono [2- ( (Meth) acryloyloxyethyl], etc .; mono (meth) acrylate of a polymer having a carboxyl group and a hydroxyl group at both ends, ω-carboxypolycaprolactone mono (meth) acrylate, etc .; a polycyclic compound having a carboxyl group and its As anhydride, 5-carboxybicyclo [2.2.1] hept 2-ene, etc. 5,6 dicarboxylate Sibi [2.2.1] hept-2-ene, respectively.

Among these compounds (a1), monocarboxylic acid and dicarboxylic acid anhydrides are preferably used. In particular, acrylic acid, methacrylic acid, and maleic anhydride are preferably used from the viewpoint of copolymerization reactivity, solubility in an aqueous alkali solution, and availability. These compounds (a1) are used individually or in combination of 2 or more types.

Copolymer [A] is preferably a structural unit derived from compound (a2) based on the sum of repeating units derived from compounds (a1) and (a2) (and optionally compound (a3)). Contains 10 to 80% by weight, particularly preferably 30 to 80% by weight. When the structural unit derived from the compound (a2) in the copolymer [A] is 10 to 80% by weight, the heat resistance, surface hardness, and peeling solution resistance of the obtained interlayer insulating film and microlens are good.

The compound (a2) is an epoxy group-containing unsaturated compound (including an oxetanyl group-containing unsaturated compound) having radical polymerizability. Specific examples of the epoxy group-containing unsaturated compound include glycidyl acrylate, glycidyl methacrylate, glycidyl α-ethyl acrylate, glycidyl α-n-propyl acrylate, glycidyl α-n-butyl acrylate, acrylic acid-3, 4-epoxybutyl, methacrylic acid-3,4-epoxybutyl, acrylic acid-6,7-epoxyheptyl, methacrylic acid-6,7-epoxyheptyl, α-ethylacrylic acid-6,7-epoxyheptyl, vinylbenzyl Examples include 2,3-epoxypropyl ether.

Among these epoxy group-containing unsaturated compounds, glycidyl methacrylate, methacrylic acid-6,7-epoxyheptyl, vinylbenzyl 2,3-epoxypropyl ether, 3,4-epoxycyclohexyl methacrylate, and the like are copolymerized. It is preferably used from the viewpoint of improving the heat resistance and surface hardness of the obtained interlayer insulating film or microlens.

Specific examples of the oxetanyl group-containing unsaturated compound include 3- (acryloyloxymethyl) oxetane, 3- (acryloyloxymethyl) -2-methyloxetane, 3- (acryloyloxymethyl) -3-ethyloxetane, 3- ( Acryloyloxymethyl) -2-trifluoromethyloxetane, 3- (acryloyloxymethyl) -2-pentafluoroethyloxetane, 3- (acryloyloxymethyl) -2-phenyloxetane, 3- (2-acryloyloxyethyl) oxetane 3- (2-acryloyloxyethyl) -2-ethyloxetane, 3- (2-acryloyloxyethyl) -3-ethyloxetane, 3- (2-acryloyloxyethyl) -2-phenyloxetane, 3- (2 -Acryloyloxyethyl) Acrylic acid esters of 2,2-difluoro-oxetane or the like;

3- (methacryloyloxymethyl) oxetane, 3- (methacryloyloxymethyl) -2-methyloxetane, 3- (methacryloyloxymethyl) -3-ethyloxetane, 3- (methacryloyloxymethyl) -2-phenyloxetane, 3- (2-methacryloyloxyethyl) oxetane, 3- (2-methacryloyloxyethyl) -2-ethyloxetane, 3- (2-methacryloyloxyethyl) -3-ethyloxetane, 33- (2-methacryloyloxyethyl) -2 -Methacrylic acid esters such as phenyloxetane. These compounds (a2) are used alone or in combination of two or more.

The compound (a3) is not particularly limited as long as it is an unsaturated compound other than the above-mentioned compounds (a1) and (a2) and has radical polymerizability. Examples of the compound (a3) include methacrylic acid chain alkyl ester, methacrylic acid cyclic alkyl ester, methacrylic acid ester having a hydroxyl group, acrylic acid cyclic alkyl ester, methacrylic acid aryl ester, acrylic acid aryl ester, and unsaturated dicarboxylic acid. Diester, bicyclounsaturated compound, maleimide compound, unsaturated aromatic compound, conjugated diene, tetrahydrofuran skeleton, furan skeleton, tetrahydropyran skeleton, pyran skeleton, unsaturated compound having a skeleton represented by the following formula (1), the following formula The phenolic hydroxyl group-containing unsaturated compound represented by (2) and other unsaturated compounds can be mentioned.

(In Formula (1), R7 is a hydrogen atom or a methyl group, and n is an integer of 1 or more.)

(In Formula (2), R1 is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, R2 to R6 are the same or different, and are a hydrogen atom, a hydroxyl group or an alkyl group having 1 to 4 carbon atoms, and B is A single bond, -COO-, or -CONH-, and m is an integer of 0 to 3, provided that at least one of R2 to R6 is a hydroxyl group.)

Specific examples of the compound (a3) include methacrylic acid chain alkyl esters such as methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, sec-butyl methacrylate, t-butyl methacrylate, 2-ethylhexyl methacrylate; methacrylic acid cyclic alkyl ester As cyclohexyl methacrylate, 2-methylcyclohexyl methacrylate, tricyclo [5.2.1.0 ^2,6 ] decan-8-yl methacrylate, tricyclo [5.2.1.0 ^2,6 ] decan-8-yloxy. Ethyl methacrylate, isobornyl methacrylate, etc .; 2-hydroxyethyl methacrylate, 3-hydroxypropyl methacrylate, 4-hydroxybutyl methacrylate as methacrylic acid ester having a hydroxyl group Acrylate, diethylene glycol monomethacrylate, 2,3-dihydroxypropyl methacrylate, 2-methacryloxyethylglycoside, 4-hydroxyphenyl methacrylate, etc .; as cyclic alkyl esters of acrylic acid, cyclohexyl acrylate, 2-methylcyclohexyl acrylate, tricyclo [5.2 .1.0 ^2,6 ] decan-8-yl acrylate, tricyclo [5.2.1.0 ^2,6 ] decan-8-yloxyethyl acrylate, isobornyl acrylate, etc .; phenyl methacrylate as phenyl ester Methacrylate, benzyl methacrylate, etc .;

As acrylic acid aryl esters, phenyl acrylate, benzyl acrylate, etc .; As unsaturated dicarboxylic acid diesters, diethyl maleate, diethyl fumarate, diethyl itaconate, etc .; As bicyclo unsaturated compounds, bicyclo [2.2.1] hept-2 -Ene, 5-methylbicyclo [2.2.1] hept-2-ene, 5-ethylbicyclo [2.2.1] hept-2-ene, 5-methoxybicyclo [2.2.1] hept- 2-ene, 5-ethoxybicyclo [2.2.1] hept-2-ene and the like;

Examples of maleimide compounds include N-phenylmaleimide, N-cyclohexylmaleimide, N-benzylmaleimide, N- (4-hydroxyphenyl) maleimide, N- (4-hydroxybenzyl) maleimide, and the like; unsaturated aromatic compounds such as styrene, α -Methyl styrene, p-methoxy styrene, etc .; conjugated dienes, 1,3-butadiene, isoprene, etc .; unsaturated compounds containing tetrahydrofuran skeleton, tetrahydrofurfuryl (meth) acrylate, 2-methacryloyloxy-propionic acid tetrahydrofur Furyl ester, 3- (meth) acryloyloxytetrahydrofuran-2-one, etc .; as unsaturated compounds containing a furan skeleton, 2-methyl-5- (3-furyl) -1-penten-3-one, furfuryl (me ) Acrylate, 1-furan-2-butyl-3-en-2-one and the like;

Unsaturated compounds containing a tetrahydropyran skeleton include (tetrahydropyran-2-yl) methyl methacrylate, 2,6-dimethyl-8- (tetrahydropyran-2-yloxy) -oct-1-en-3-one, 2 -Methacrylic acid tetrahydropyran-2-yl ester, 1- (tetrahydropyran-2-oxy) -butyl-3-en-2-one, etc .; as unsaturated compounds containing a pyran skeleton, 4- (1,4- Dioxa-5-oxo-6-heptenyl) -6-methyl-2-pyrone and the like; as an unsaturated compound containing a skeleton represented by the above formula (1), polyethylene glycol (n = 2 to 10) mono (meta) ) Acrylate, polypropylene glycol (n = 2 to 10) mono (meth) acrylate, and the like.

Further, examples of the unsaturated compound containing a phenol skeleton include compounds represented by the following formulas (3) to (7) from the compound represented by the above formula (2) according to the definitions of B and m.

(In the formula (3), n is an integer of 1 to 3, and the definitions of R1, R2, R3, R4, R5 and R6 are the same as those in the above formula (2).)

(In formula (4), the definitions of R1, R2, R3, R4, R5 and R6 are the same as those in formula (2) above).

(In the formula (5), n is an integer of 1 to 3, and the definitions of R1, R2, R3, R4, R5 and R6 are the same as the definitions in the above formula (2).)

(In formula (6), the definitions of R1, R2, R3, R4, R5 and R6 are the same as those in formula (2) above).

(In formula (7), the definitions of R1, R2, R3, R4, R5, and R6 are the same as those in formula (2) above).

Examples of other unsaturated compounds include acrylonitrile, methacrylonitrile, vinyl chloride, vinylidene chloride, acrylamide, methacrylamide, and vinyl acetate.

Among examples of these compounds (a3), methacrylic acid chain alkyl ester, methacrylic acid cyclic alkyl ester, maleimide compound, tetrahydrofuran skeleton, furan skeleton, tetrahydropyran skeleton, pyran skeleton, skeleton represented by the above formula (1) An unsaturated compound having a hydroxyl group and a phenolic hydroxyl group-containing unsaturated compound represented by the above formula (2) are preferably used. Among these, styrene, t-butyl methacrylate, tricyclo [5.2.1.0 ^2,6 ] decan-8-yl methacrylate, p-methoxystyrene, 2-methylcyclohexyl acrylate, N-phenylmaleimide, N- Cyclohexylmaleimide, tetrahydrofurfuryl (meth) acrylate, polyethylene glycol (n = 2 to 10) mono (meth) acrylate, 3- (meth) acryloyloxytetrahydrofuran-2-one, 4-hydroxybenzyl (meth) acrylate, 4- Hydroxyphenyl (meth) acrylate, o-hydroxystyrene, p-hydroxystyrene, and α-methyl-p-hydroxystyrene are preferable from the viewpoint of copolymerization reactivity and solubility in an aqueous alkali solution. These compounds (a3) are used individually or in combination of 2 or more types.

The copolymer [A] used in the present invention is a total of repeating units derived from the compounds (a1) and (a2) (and optionally the compound (a3)) as structural units derived from the compound (a3). Based on the above, preferably 0 to 60% by weight, particularly preferably 5 to 50% by weight may be contained. When the amount of the structural unit is 60% by weight or less, the molecular weight of the copolymer can be easily controlled, and a radiation-sensitive resin composition in which developability, radiation sensitivity, and the like are balanced at a higher level can be obtained.

Preferable specific examples of each component of the copolymer [A] include methacrylic acid / tricyclo [5.2.1.0 ^2,6 ] decan-8-yl methacrylate / 2-methylcyclohexyl acrylate / glycidyl methacrylate / N- (3,5-dimethyl-4-hydroxybenzyl) methacrylamide, methacrylic acid / tetrahydrofurfuryl methacrylate / glycidyl methacrylate / N-cyclohexylmaleimide / lauryl methacrylate / α-methyl-p-hydroxystyrene, styrene / methacrylic acid / Glycidyl methacrylate / (3-ethyloxetane-3-yl) methacrylate / tricyclo [5.2.1.0 ^2,6 ] decan-8-yl methacrylate.

Next, a polymerization method for producing the copolymer [A] will be described.
The polymerizable unsaturated compound constituting the copolymer [A] can be carried out by polymerizing in a solvent in the presence of a molecular weight control agent using a radical polymerization initiator, whereby the molecular weight and A copolymer [A] having a controlled molecular weight distribution can be obtained.

  The molecular weight controlling agent used in the present invention has a bis (alkyl mercapto-thiocarbonyl) disulfide or bis (benzyl mercapto-thiocarbonyl) disulfide structure, and the copolymer produced using this molecular weight controlling agent is It is effective for expressing storage stability, radiation sensitivity, etc. as a good radiation sensitive resin composition. In addition, the molecular weight control agent used in the present invention is stable over time, can synthesize the copolymer [A] stably, and as a result, can improve the quality of the resin composition.

In the formula (1) showing a molecular weight control agent, examples of the alkyl group having 4 to 18 carbon atoms of Z ¹ and Z ² include an n-butyl group, a t-butyl group, an n-heptyl group, an n-hexyl group, Examples include n-pentyl group, n-octyl group, n-nonyl group, n-decyl group, n-dodecyl group, t-dodecyl group, n-tetradecyl group, n-hexadecyl group, n-octadecyl group and the like. . Among these alkyl groups, n-hexyl group, n-pentyl group, n-octyl group, n-decyl group, n-dodecyl group and the like are preferable, and in particular, n-octyl group, n-decyl group and n-dodecyl group. Etc. are preferred.
In Z ¹ and Z ² , examples of the benzyl group and the optionally substituted benzyl group include o-chlorobenzyl group, p-chlorobenzyl group, o-cyanobenzyl group, p-cyanobenzyl group, o- A methoxybenzyl group, p-methoxybenzyl group, etc. can be mentioned. Of these substitutions, a benzyl group is particularly preferred.
In the polymerization, the molecular weight control agents can be used alone or in admixture of two or more.

  In the polymerization, one or more other molecular weight control agents such as α-methylstyrene dimer and t-dodecyl mercaptan can be used in combination with the molecular weight control agent.

  Further, the polymerization of the polymerizable unsaturated compound in the presence of the molecular weight control agent may take the form of living radical polymerization in which an active radical is formed at the growth terminal of the polymer chain.

  When the polymerization takes the form of living radical polymerization, when the polymerizable unsaturated compound contains a compound having a functional group that may deactivate an active radical such as a carboxyl group, the growth terminal should not be deactivated. Therefore, if necessary, the functional group can be protected by, for example, esterification and then polymerized, and then deprotected to obtain the copolymer [A].

The radical polymerization initiator is appropriately selected according to the type of the polymerizable unsaturated compound used. For example, 2,2′-azobisisobutyronitrile, 2,2′-azobis- (2 , 4-dimethylvaleronitrile), 2,2′-azobis- (4-methoxy-2,4-dimethylvaleronitrile), 4,4′-azobis (4-cyanovaleric acid), dimethyl-2,2′-azobis Azo compounds such as (2-methylpropionate) and 2,2′-azobis (4-methoxy-2,4-dimethylvaleronitrile);
Of these radical polymerization initiators, 2,2′-azobisisobutyronitrile, 2,2′-azobis (2,4-dimethylvaleronitrile) and the like are preferable.
The radical polymerization initiators can be used alone or in admixture of two or more.

  In the said polymerization, the usage-amount of a radical polymerization initiator is 0.1-50 mass parts normally with respect to 100 weight part of polymerizable unsaturated compounds, Preferably it is 0.1-20 mass part.

  Moreover, the usage-amount of a molecular weight control agent is 0.1-25 mass parts normally with respect to 100 mass parts of polymerizable unsaturated compounds, Preferably it is 0.2-16 mass parts, Most preferably, it is 0.4-8. Part by mass. In this case, when the usage-amount of a molecular weight control agent is 0.1-25 mass parts, the control effect of molecular weight and molecular weight distribution is acquired especially.

  Moreover, the usage-amount of another molecular weight control agent is 200 mass parts or less normally with respect to a total molecular weight control agent, Preferably it is 40 mass parts or less. In this case, if the use ratio of the other molecular weight control agent exceeds 200 parts by mass, the intended effect of the present invention may be impaired. Moreover, the usage-amount of a solvent is 50-1,000 mass parts normally with respect to 100 mass parts of polymerizable unsaturated compounds, Preferably it is 100-500 mass parts. The polymerization temperature is usually 0 to 150 ° C., preferably 50 to 120 ° C., and the polymerization time is usually 10 minutes to 20 hours, preferably 30 minutes to 6 hours.

  By using such a copolymer [A] having Mw and Mw / Mn, it is possible to easily form a patterned thin film having high sensitivity to radiation and excellent adhesion, and sublimation during baking. It can be used to form a high-transmittance, highly-reliable interlayer insulating film, and when it is used to form microlenses, it can be used to form microlenses with high transmittance and good melt shape. It is to provide a radiation-sensitive resin composition excellent in stability.

Among the solvents used for the production of the copolymer [A], ethylene glycol alkyl ether acetate, diethylene glycol, propylene glycol monoalkyl ether, and propylene glycol alkyl ether acetate are preferable. Among these solvents, diethylene glycol dimethyl ether, diethylene glycol ethyl methyl ether, propylene glycol methyl ether, propylene glycol ethyl ether, propylene glycol methyl ether acetate, and methyl 3-methoxypropionate are preferable.

II. [B] Component The [B] component used in the present invention is a 1,2-quinonediazide compound that generates a carboxylic acid upon irradiation with radiation. As the 1,2-quinonediazide compound, a condensate of a phenolic compound or an alcoholic compound (hereinafter referred to as “mother nucleus”) and 1,2-naphthoquinonediazidesulfonic acid halide can be used.

Examples of the mother nucleus of the component [B] include trihydroxybenzophenone, tetrahydroxybenzophenone, pentahydroxybenzophenone, hexahydroxybenzophenone, (polyhydroxyphenyl) alkane, and other mother nuclei.

Specific examples of these mother nuclei include 2,3,4-trihydroxybenzophenone, 2,4,6-trihydroxybenzophenone and the like as trihydroxybenzophenone; 2,2 ′, 4,4 ′ as tetrahydroxybenzophenone -Tetrahydroxybenzophenone, 2,3,4,3'-tetrahydroxybenzophenone, 2,3,4,4'-tetrahydroxybenzophenone, 2,3,4,2'-tetrahydroxy-4'-methylbenzophenone, 2, , 3,4,4′-tetrahydroxy-3′-methoxybenzophenone, etc .; 2,3,4,2 ′, 6′-pentahydroxybenzophenone etc. as pentahydroxybenzophenone; 2,4,6 as hexahydroxybenzophenone , 3 ′, 4 ′, 5′-Hexahydroxybenzopheno 3,4,5,3 ′, 4 ′, 5′-hexahydroxybenzophenone, etc .; (polyhydroxyphenyl) alkanes such as bis (2,4-dihydroxyphenyl) methane, bis (p-hydroxyphenyl) methane, tri (P-hydroxyphenyl) methane, 1,1,1-tri (p-hydroxyphenyl) ethane, bis (2,3,4-trihydroxyphenyl) methane, 2,2-bis (2,3,4-tri Hydroxyphenyl) propane, 1,1,3-tris (2,5-dimethyl-4-hydroxyphenyl) -3-phenylpropane, 4,4 ′-[1- [4- [1- [4-hydroxyphenyl] -1-methylethyl] phenyl] ethylidene] bisphenol, bis (2,5-dimethyl-4-hydroxyphenyl) -2-hydroxyphenylmethane ;

In addition, 1,2-naphthoquinonediazide sulfonic acid amide in which the ester bond of the mother nucleus exemplified above is changed to an amide bond, for example, 2,3,4-trihydroxybenzophenone-1,2-naphthoquinonediazide-4-sulfonic acid amide Etc. are also preferably used.

Among these mother nuclei, in particular, 2,3,4,4′-tetrahydroxybenzophenone, 4,4 ′-[1- [4- [1- [4-hydroxyphenyl] -1-methylethyl] phenyl] ethylidene Bisphenol is preferred.

On the other hand, 1,2-naphthoquinone diazide sulfonic acid halide is preferably 1,2-naphthoquinone diazide sulfonic acid chloride. Specific examples of 1,2-naphthoquinone diazide sulfonic acid chloride include 1,2-naphthoquinone diazide-4-sulfonic acid chloride and 1,2-naphthoquinone diazide-5-sulfonic acid chloride. Among these, it is preferable to use 1,2-naphthoquinonediazide-5-sulfonic acid chloride.

In the condensation reaction between the mother nucleus and 1,2-naphthoquinonediazidesulfonic acid halide, preferably 30 to 85 mol%, more preferably 50 to 70 mol%, based on the number of OH groups in the phenolic compound or alcoholic compound. 1,2-naphthoquinonediazide sulfonic acid halide corresponding to the above can be used. The condensation reaction can be carried out by a known method. As a compound obtained by such a condensation reaction, 4,4 ′-[1- {4- (1- [4-hydroxyphenyl] -1-methylethyl) phenyl} ethylidene] bisphenol-1,2-naphthoquinonediazide is used. And -5-sulfonic acid ester.

The 1,2-quinonediazide compound of the component [B] can be used alone or in combination of two or more. [B] The usage-amount of a component becomes like this. Preferably it is 5-100 mass parts with respect to 100 mass parts of alkali-soluble resin of a [A] component, More preferably, it is 10-50 mass parts. [B] When the use ratio of the component is 5 to 100 parts by mass with respect to 100 parts by mass of the alkali-soluble resin of the [A] component, The difference becomes large and good patterning is possible. Moreover, the heat resistance and solvent resistance of the obtained interlayer insulating film or microlens are improved.

III. Other components The radiation-sensitive resin composition according to the present invention contains the above-mentioned components [A] and [B], but [C] a heat-sensitive acid generating compound, [D] at least one ethylenically unsaturated double compound. A polymerizable compound having a bond, an epoxy resin other than the [E] copolymer [A], a [F] surfactant, or a [G] adhesion assistant can be contained.

The above-mentioned [C] heat-sensitive acid generating compound can be used to improve heat resistance and hardness (hereinafter sometimes referred to as “C component”). Specific examples thereof include onium salts such as sulfonium salts, benzothiazonium salts, ammonium salts, and phosphonium salts.
Specific examples of the sulfonium salt include alkylsulfonium salts, benzylsulfonium salts, dibenzylsulfonium salts, substituted benzylsulfonium salts and the like.
Specific examples thereof include alkylsulfonium salts such as 4-acetophenyldimethylsulfonium hexafluoroantimonate, 4-acetoxyphenyldimethylsulfonium hexafluoroarsenate, dimethyl-4- (benzyloxycarbonyloxy) phenylsulfonium hexafluoroantimony. Nate etc .;
Examples of benzylsulfonium salts include benzyl-4-hydroxyphenylmethylsulfonium hexafluoroantimonate, benzyl-4-hydroxyphenylmethylsulfonium hexafluorophosphate, 4-acetoxyphenylbenzylmethylsulfonium hexafluoroantimonate, and benzyl-4-methoxyphenylmethyl. Sulfonium hexafluoroantimonate, benzyl-2-methyl-4-hydroxyphenylmethylsulfonium hexafluoroantimonate, etc .;
Examples of the dibenzylsulfonium salt include dibenzyl-4-hydroxyphenylsulfonium hexafluoroantimonate and dibenzyl-4-hydroxyphenylsulfonium hexafluorophosphate.
Specific examples of the benzothiazonium salt include 3-benzylbenzothiazonium hexafluoroantimonate, 3-benzylbenzothiazonium hexafluorophosphate, benzylbenzothiazo such as 3-benzylbenzothiazonium tetrafluoroborate. Examples thereof include nium salts.
Of these, sulfonium salts and benzothiazonium salts are preferably used, particularly 4-acetoxyphenyldimethylsulfonium hexafluoroarsenate, benzyl-4-hydroxyphenylmethylsulfonium hexafluorophosphate, benzyl-4-hydroxyphenylmethylsulfonium hexanium. Fluoroantimonate, 4-acetoxyphenylbenzylmethylsulfonium hexafluoroantimonate, dibenzyl-4-hydroxyphenylsulfonium hexafluoroantimonate, 4-acetoxyphenylbenzylsulfonium hexafluoroantimonate, 3-benzylbenzothiazolium hexafluoroantimonate Is preferably used.

Examples of these commercially available products include Sun-Aid SI-L85, SI-L110, SI-L145, SI-L150, SI-L160 (manufactured by Sanshin Chemical Industry Co., Ltd.).
The proportion of component [C] used is preferably 20 parts by weight or less, more preferably 5 parts by weight or less, based on 100 parts by weight of copolymer [A]. When this usage-amount is 20 mass parts or less, a deposit does not precipitate in a coating-film formation process, but the coating film with favorable hardness can be formed.

  Examples of the polymerizable compound having at least one ethylenically unsaturated double bond as component [D] (hereinafter sometimes referred to as “component D”) include monofunctional (meth) acrylate, bifunctional ( Preferable examples include (meth) acrylate or tri- or higher functional (meth) acrylate.

  Examples of the monofunctional (meth) acrylate include carbitol (meth) acrylate, isobornyl (meth) acrylate, 3-methoxybutyl (meth) acrylate, 2- (meth) acryloyloxyethyl-2-hydroxypropyl phthalate, and the like. It is done. As these commercial products, for example, Aronix M-101, M-111, M-114 (above, manufactured by Toagosei Co., Ltd.), KAYARAD TC-110S, TC-120S (above, Nippon Kayaku Co., Ltd.) ) Co., Ltd.), Biscoat 158, 2311 (above, manufactured by Osaka Organic Chemical Industry Co., Ltd.).

  Examples of the bifunctional (meth) acrylate include ethylene glycol (meth) acrylate, 1,9-nonanediol di (meth) acrylate, polypropylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, and bisphenoxyethanol full Examples include orange acrylate and bisphenoxyethanol full orange acrylate. As these commercial products, for example, Aronix M-210, M-240, M-6200 (above, manufactured by Toagosei Co., Ltd.), KAYARAD HDDA, HX-220, R-604 (above, Nippon Kayaku) Medicine Co., Ltd.), Viscoat 260, 312 and 335HP (above, Osaka Organic Chemical Industries, Ltd.).

  Examples of the trifunctional or higher functional (meth) acrylates include trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, and dipentaerythritol. Hexa (meth) acrylate and the like can be mentioned, and examples of commercially available products thereof include Aronix M-309, M-400, M-405, M-450, M-7100, M-8030, and M- 8060 (above, manufactured by Toagosei Co., Ltd.), KAYARAD TMPTA, DPHA, DPCA-20, DPCA-30, DPCA-60, DPCA-60, DPCA-120 (above, Nippon Kayaku Co., Ltd.), Biscoat 295, 300, 360, GPT, 3PA, 400 (manufactured by Osaka Organic Chemical Industry Co., Ltd.), and the like.

Of these, trifunctional or higher functional (meth) acrylates are preferably used, and among them, trimethylolpropane tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol hexa (meth) acrylate, pentaerythritol tetra (meth) A mixture of acrylate) and dipentaerythritol hexa (meth) acrylate is particularly preferred.
These monofunctional, bifunctional, or trifunctional or higher (meth) acrylates are used alone or in combination. The proportion of the component [D] used is preferably 50 parts by weight or less, more preferably 30 parts by weight or less with respect to 100 parts by weight of the copolymer [A].

  When the amount of the [D] component used in the radiation-sensitive resin composition of the present invention is 50 weight or less, the heat resistance, surface hardness, radiation sensitivity, etc. of the obtained interlayer insulating film or microlens can be improved.

  The epoxy resin other than the copolymer [A] as the [E] component (hereinafter sometimes referred to as “E component”) is not limited as long as the compatibility is not affected. Preferably, bisphenol A type epoxy resin, phenol novolak type epoxy resin, cresol novolak type epoxy resin, cyclic aliphatic epoxy resin, glycidyl ester type epoxy resin, glycidyl amine type epoxy resin, heterocyclic epoxy resin, glycidyl methacrylate ) Polymerized resins and the like can be mentioned. Of these, bisphenol A type epoxy resins, cresol novolac type epoxy resins, glycidyl ester type epoxy resins and the like are particularly preferable.

[E] The usage-amount of a component becomes like this. Preferably it is 30 weight part or less with respect to 100 weight part of copolymers [A]. When the proportion of the component [E] used is 30 parts by weight or less, the heat resistance and surface hardness of the protective film or insulating film obtained can be further improved.
The copolymer [A] can also be referred to as an “epoxy resin”, but differs from the component [E] in that it has alkali solubility. [E] component is alkali-insoluble.

  In the radiation-sensitive resin composition of the present invention, a surfactant can be used in order to further improve the coatability (hereinafter sometimes referred to as “[F] component”). As the [F] component that can be used here, a fluorine-based surfactant and a silicone-based surfactant can be suitably used.

  Specific examples of the fluorosurfactant include 1,1,2,2-tetrafluorooctyl (1,1,2,2-tetrafluoropropyl) ether, 1,1,2,2-tetrafluorooctylhexyl ether. , Octaethylene glycol di (1,1,2,2-tetrafluorobutyl) ether, hexaethylene glycol (1,1,2,2,3,3-hexafluoropentyl) ether, octapropylene glycol di (1,1 , 2,2-tetrafluorobutyl) ether, hexapropylene glycol di (1,1,2,2,3,3-hexafluoropentyl) ether, sodium perfluorododecyl sulfonate, 1,1,2,2,8 , 8,9,9,10,10-decafluorododecane, 1,1,2,2,3,3-hexafluorodecane, etc. Sodium Zensuruhon acid; fluoroalkyl polyoxyethylene ethers; fluoroalkyl ammonium iodide, fluoroalkyl polyoxyethylene ethers, perfluoroalkyl polyoxyethylene ethanol; can be exemplified fluorine-based alkyl esters; perfluoroalkyl alkoxylates. These commercial products include BM-1000, BM-1100 (manufactured by BM Chemie), MegaFuck F142D, F172, F173, F183, F178, F191, F191 (and above, Dainippon Ink). Chemical Industries, Ltd.), Fluorad FC-170C, FC-171, FC-430, FC-431 (above, manufactured by Sumitomo 3M), Surflon S-112, S-113, S-131, S-141, S-145, S-382, SC-101, SC-102, SC-103, SC-104, SC-105, SC-106 (manufactured by Asahi Glass Co., Ltd.) ), F-top EF301, 303, and 352 (manufactured by Shin-Akita Kasei Co., Ltd.).

  Examples of the silicone surfactant include DC3PA, DC7PA, FS-1265, SF-8428, SH11PA, SH21PA, SH28PA, SH29PA, SH30PA, SH-190, SH-193, SZ-6032 (above, Toray Dow Corning) -Silicone Co., Ltd.), TSF-4440, TSF-4300, TSF-4445, TSF-4446, TSF-4460, TSF-4442 (above, GE Toshiba Silicone Co., Ltd.) are commercially available. You can list what you have.

These surfactants can be used alone or in combination of two or more.
These [F] components are preferably used in an amount of 0.1 to 10 parts by weight, more preferably 0.15 to 5 parts by weight, based on 100 parts by weight of the copolymer [A]. When the amount of the component [F] used is 0.1 to 10 parts by weight, it is possible to reduce the occurrence of film erosion when the coating film is formed on the substrate.

  In the radiation sensitive resin composition of the present invention, an adhesion assistant (hereinafter also referred to as [G] component) can be used in order to improve the adhesion to the substrate. As such [G] component, a functional silane coupling agent is preferably used, and examples thereof include a silane coupling agent having a reactive substituent such as a carboxyl group, a methacryloyl group, an isocyanate group, and an epoxy group. Specifically, trimethoxysilylbenzoic acid, γ-methacryloxypropyltrimethoxysilane, vinyltriacetoxysilane, vinyltrimethoxysilane, γ-isocyanatopropyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane and the like. Such [G] component is preferably used in an amount of 1 to 20 parts by weight, more preferably 3 to 15 parts by weight, based on 100 parts by weight of the copolymer [A]. When the amount of the adhesion assistant is 1 to 20 parts by weight, the adhesion of the resulting pattern to the substrate is good.

IV. Radiation-sensitive resin composition The radiation-sensitive resin composition according to the present invention is obtained by uniformly mixing the above-described components [A] and [B] and optional components [C] to [G]. Prepared. The radiation-sensitive resin composition is preferably dissolved in an appropriate solvent and used in a solution state. Solvents used for the preparation of the radiation sensitive resin composition include those that uniformly dissolve the [A] and [B] components and the optional components [C] to [G] and do not react with each component. Used. As such a solvent, the thing similar to what was enumerated above can be mentioned as an example of the solvent which can be used in order to manufacture alkali-soluble resin of [A] component.

  As such a solvent, alcohol, glycol ether, ethylene glycol alkyl ether acetate, ester and diethylene glycol are preferably used from the viewpoints of solubility of each component, reactivity with each component, ease of film formation, and the like. Among these, benzyl alcohol, 2-phenylethyl alcohol, 3-phenyl-1-propanol, ethylene glycol monobutyl ether acetate, diethylene glycol monoethyl ether acetate, diethylene glycol diethyl ether, diethylene glycol ethyl methyl ether, diethylene glycol dimethyl ether, propylene glycol monomethyl ether, Purpylene glycol monomethyl ether acetate, methyl methoxypropionate, and ethyl ethoxypropionate can be particularly preferably used.

  In order to improve the in-plane uniformity of the film thickness, a high boiling point solvent can be used in combination with these solvents. Specific examples of the high boiling point solvent that can be used in combination include N-methylformamide, N, N-dimethylformamide, N-methylformanilide, N-methylacetamide, N, N-dimethylacetamide, N-methylpyrrolidone, dimethylsulfoxide, benzyl Ethyl ether, dihexyl ether, acetonyl acetone, isophorone, caproic acid, caprylic acid, 1-octanol, 1-nonanol, benzyl acetate, ethyl benzoate, diethyl oxalate, diethyl maleate, γ-butyrolactone, ethylene carbonate, propylene carbonate , Phenyl cellosolve acetate and the like. Of these, N-methylpyrrolidone, γ-butyrolactone, and N, N-dimethylacetamide are preferable.

  When a normal solvent and a high-boiling solvent are used in combination as a solvent for the radiation-sensitive resin composition, the amount of the high-boiling solvent used is preferably 50% by weight or less, more preferably 40% by weight or less, based on the total amount of the solvent. More preferably, it can be 30 weight% or less. When the amount of the high-boiling solvent used is 50% by weight or less, the film thickness uniformity, sensitivity, and residual film ratio of the coating film are good.

When preparing the radiation-sensitive resin composition in a solution state, components other than the solvent in the solution (that is, the total of the above-mentioned [A] and [B] components and optional [C] to [G] components) The ratio of (amount) can be arbitrarily set according to the purpose of use, the value of the desired film thickness, and the like. The ratio of components other than such a solvent is preferably 5 to 50% by weight, more preferably 10 to 40% by weight, and still more preferably 15 to 35% by weight. The composition solution thus prepared can be used after being filtered using a Millipore filter having a pore size of about 0.2 μm.

V. Formation of Interlayer Insulating Film and Microlens Next, a method for forming an interlayer insulating film and a microlens using the radiation sensitive resin composition according to the present invention will be described. The method for forming an interlayer insulating film or microlens of the present invention includes the following steps in the order described below:
(1) The process of forming the coating film of the radiation sensitive resin composition of this invention on a board | substrate,
(2) A step of irradiating at least a part of the coating film of step (1),
(3) A step of developing the coating film irradiated with radiation in the step (2), and (4) A step of heating the coating film developed in the step (3).

(1) The process of forming the coating film of the radiation sensitive resin composition of this invention on a board | substrate In this process, the solution formed from the radiation sensitive resin composition of this invention is apply | coated to the substrate surface, Preferably The solvent is removed by pre-baking to form a coating film of the radiation-sensitive resin composition. Examples of the types of substrates that can be used include glass substrates, silicon wafers, and substrates on which various metals are formed.

  The coating method of the composition solution is not particularly limited, and 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 ink jet method or the like is adopted. can do. In particular, a spin coating method and a slit die coating method are preferable. Appropriate conditions for pre-baking vary depending on the type of each component, the use ratio, and the like. For example, prebaking can be performed at 60 to 110 ° C. for about 30 seconds to 15 minutes. The film thickness of the coating film after pre-baking is preferably about 3 to 6 μm, for example, when an interlayer insulating film is formed, and about 0.5 to 3 μm when a microlens is formed.

(2) Step of irradiating at least a part of the coating film in step (1) In this step, the coating film formed in step (1) is irradiated with radiation through a mask having a predetermined pattern. . Examples of radiation used at this time include ultraviolet rays, far ultraviolet rays, and charged particle beams. Examples of ultraviolet rays include g-line (wavelength 436 nm), i-line (wavelength 365 nm), and the like. Examples of far ultraviolet rays include KrF excimer laser. Among these radiations, ultraviolet rays are preferable, and radiation containing g-line and / or i-line is particularly preferable. The exposure dose, 50~1,500J / ^{m 2} In the case of forming an interlayer insulating film, in the case of forming the micro lenses is preferably set to 50~2,000J / ^{m 2.}

(3) Step of developing the coating film irradiated with radiation in step (2) In this step, the coating film irradiated with radiation in step (2) is subjected to development treatment using a developer, and Patterning is performed by removing the irradiated portion. Examples of the developer used for the development treatment include an aqueous solution of an alkali (basic compound) such as sodium hydroxide, potassium hydroxide, sodium carbonate, ammonia, tetramethylammonium hydroxide, and tetraethylammonium hydroxide. . 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 such an alkaline aqueous solution, or various organic solvents that dissolve the composition according to the present invention may be used as a developing solution. it can. Further, as a developing method, for example, a liquid piling method, a dipping method, a rocking dipping method, a shower method and the like can be appropriately performed. The development time varies depending on the composition of the composition used, but can be, for example, 30 to 120 seconds.

(4) Step of heating the coating film developed in step (3) In this step, the coating film developed in step (3) is heated and dried. That is, after the development step (3), the patterned thin film is preferably rinsed by running water washing or the like, and more preferably, the entire surface is exposed to radiation (post-exposure step) using a high-pressure mercury lamp or the like. The 1,2-quinonediazite compound remaining in the thin film is decomposed. Thereafter, the thin film is subjected to a heat treatment (post-bake treatment) by a heating device such as a hot plate or an oven, whereby the thin film is cured. The exposure dose in the post-exposure step is preferably about 2,000 to 5,000 J / m ² . Moreover, the heating temperature in this hardening process is 120-250 degreeC, for example. Although heating time changes with kinds of heating apparatus, for example, when performing heat processing on a hotplate, it can be set to 30 to 90 minutes when performing heat processing in oven, for example. At this time, a step baking method or the like in which a heating process is performed twice or more can also be used.

  The interlayer insulating film formed as described above has good adhesion to the substrate, is excellent in solvent resistance and heat resistance, and has high transmittance and low dielectric constant. Therefore, the interlayer insulating film can be suitably used for electronic parts. Further, the microlenses formed as described above have good adhesion to the substrate, excellent solvent resistance and heat resistance, and have high transmittance and a good melt shape. Therefore, the microlens can be suitably used as a microlens for a solid-state imaging device. The shape of the microlens of the present invention is a semi-convex lens shape as shown in FIG.

EXAMPLES The present invention will be described more specifically with reference to the following synthesis examples and examples. However, the present invention is not limited to these synthesis examples and examples.

Synthesis Example 1 Synthesis of Copolymer [A-1] In a flask equipped with a condenser and a stirrer, 7 parts by weight of 2,2′-azobis (2,4-dimethylvaleronitrile) and 220 parts by weight of diethylene glycol ethyl methyl ether were added. Prepared. Subsequently, 7 parts by weight of methacrylic acid, 2 parts by weight of styrene, 2 parts by weight of tricyclo [5.2.1.0 ^2,6 ] decan-8-yl methacrylate, 20 parts by weight of vinylbenzyl 2,3-epoxypropyl ether, methacrylic acid 40 parts by weight of glycidyl, 29 parts by weight of 2,3,4,5-tetrahydrofurfuryl methacrylate, and 3 parts by weight of bis (benzylmercapto-thiocarbonyl) disulfide (molecular weight controlling agent) were charged and purged with nitrogen, followed by gentle stirring. Started. The temperature of the solution was raised to 70 ° C., and this temperature was maintained for 4 hours to obtain a polymer solution containing the copolymer [A-1].
The copolymer [A-1] had a polystyrene equivalent weight average molecular weight (Mw) of 7000 and a molecular weight distribution (Mw / Mn) of 1.4. Moreover, the solid content concentration of the polymer solution obtained here was 33.0% by weight.

Synthesis Example 2 Synthesis of copolymer [A-2] In a flask equipped with a condenser and a stirrer, 7 parts by weight of 2,2′-azobis (2,4-dimethylvaleronitrile) and 220 parts by weight of diethylene glycol ethyl methyl ether were added. Prepared. Subsequently, 7 parts by weight of methacrylic acid, 2 parts by weight of styrene, 2 parts by weight of tricyclo [5.2.1.0 ^2,6 ] decan-8-yl methacrylate, 20 parts by weight of vinylbenzyl 2,3-epoxypropyl ether, methacrylic acid After 40 parts by weight of glycidyl, 29 parts by weight of 2,3,4,5-tetrahydrofurfuryl methacrylate and 3 parts by weight of bis (n-octylmercapto-thiocarbonyl) disulfide (molecular weight control agent) were charged and the atmosphere was replaced with nitrogen, it was gently Stirring was started. The temperature of the solution was raised to 70 ° C., and this temperature was maintained for 4 hours to obtain a polymer solution containing the copolymer [A-2].
The copolymer [A-2] had a polystyrene equivalent weight average molecular weight (Mw) of 8000 and a molecular weight distribution (Mw / Mn) of 1.4. Moreover, the solid content concentration of the polymer solution obtained here was 33.0% by weight.

Synthesis Example 2 Synthesis of Copolymer [A-3] In a flask equipped with a condenser and a stirrer, 7 parts by weight of 2,2′-azobis (2,4-dimethylvaleronitrile) and 220 parts by weight of diethylene glycol ethyl methyl ether were added. Prepared. Subsequently, 7 parts by weight of methacrylic acid, 2 parts by weight of styrene, 2 parts by weight of tricyclo [5.2.1.0 ^2,6 ] decan-8-yl methacrylate, 20 parts by weight of vinylbenzyl 2,3-epoxypropyl ether, methacrylic acid After 40 parts by weight of glycidyl, 29 parts by weight of 2,3,4,5-tetrahydrofurfuryl methacrylate and 3 parts by weight of bis (n-dodecylmercapto-thiocarbonyl) disulfide (molecular weight control agent) were charged and the atmosphere was replaced with nitrogen, it was gently Stirring was started. The temperature of the solution was raised to 70 ° C., and this temperature was maintained for 4 hours to obtain a polymer solution containing the copolymer [A-3].
The copolymer [A-3] had a polystyrene equivalent weight average molecular weight (Mw) of 9000 and a molecular weight distribution (Mw / Mn) of 1.5. The solid content concentration of the polymer solution obtained here was 32.0% by weight.

Comparative Synthesis Example 1
A flask equipped with a condenser and a stirrer was charged with 7 parts by weight of 2,2′-azobis (2,4-dimethylvaleronitrile) and 220 parts by weight of diethylene glycol ethyl methyl ether. Subsequently, 7 parts by weight of methacrylic acid, 2 parts by weight of styrene, 2 parts by weight of tricyclo [5.2.1.0 ^2,6 ] decan-8-yl methacrylate, 20 parts by weight of vinylbenzyl 2,3-epoxypropyl ether, methacrylic acid After 40 parts by weight of glycidyl and 29 parts by weight of 2,3,4,5-tetrahydrofurfuryl methacrylate were charged and purged with nitrogen, stirring was started gently. The temperature of the solution was raised to 70 ° C., and this temperature was maintained for 4 hours to obtain a polymer solution containing the copolymer [a-1].
The copolymer [a-1] had a polystyrene equivalent weight average molecular weight (Mw) of 27000 and a molecular weight distribution (Mw / Mn) of 3.4. Moreover, the solid content concentration of the polymer solution obtained here was 33.0% by weight.

Comparative Synthesis Example 2
A flask equipped with a condenser and a stirrer was charged with 7 parts by weight of 2,2′-azobis (2,4-dimethylvaleronitrile) and 220 parts by weight of diethylene glycol ethyl methyl ether. Subsequently, 7 parts by weight of methacrylic acid, 2 parts by weight of styrene, 2 parts by weight of tricyclo [5.2.1.0 ^2,6 ] decan-8-yl methacrylate, 20 parts by weight of vinylbenzyl 2,3-epoxypropyl ether, methacrylic acid After 40 parts by weight of glycidyl, 29 parts by weight of 2,3,4,5-tetrahydrofurfuryl methacrylate and 5 parts by weight of α-methylstyrene dimer were charged and purged with nitrogen, stirring was started gently. The temperature of the solution was raised to 70 ° C., and this temperature was maintained for 4 hours to obtain a polymer solution containing the copolymer [a-2].
The copolymer [a-2] had a weight average molecular weight (Mw) in terms of polystyrene of 8500 and a molecular weight distribution (Mw / Mn) of 2.0. Moreover, the solid content concentration of the polymer solution obtained here was 33.0% by weight.

Comparative Synthesis Example 3
A flask equipped with a condenser and a stirrer was charged with 7 parts by weight of 2,2′-azobis (2,4-dimethylvaleronitrile) and 220 parts by weight of diethylene glycol ethyl methyl ether. Subsequently, 7 parts by weight of methacrylic acid, 2 parts by weight of styrene, 2 parts by weight of tricyclo [5.2.1.0 ^2,6 ] decan-8-yl methacrylate, 20 parts by weight of vinylbenzyl 2,3-epoxypropyl ether, methacrylic acid After 40 parts by weight of glycidyl, 29 parts by weight of 2,3,4,5-tetrahydrofurfuryl methacrylate and 3 parts by weight of tetraethylthiuram disulfide (molecular weight control agent) were charged and purged with nitrogen, stirring was started gently. The temperature of the solution was raised to 70 ° C., and this temperature was maintained for 4 hours to obtain a polymer solution containing the copolymer [a-3].
The copolymer [a-3] had a polystyrene-reduced weight average molecular weight (Mw) of 8,100 and a molecular weight distribution (Mw / Mn) of 1.5. The solid content concentration of the polymer solution obtained here was 32.7% by weight.

Comparative Synthesis Example 4
A flask equipped with a condenser and a stirrer was charged with 7 parts by weight of 2,2′-azobis (2,4-dimethylvaleronitrile) and 220 parts by weight of diethylene glycol ethyl methyl ether. Subsequently, 7 parts by weight of methacrylic acid, 2 parts by weight of styrene, 2 parts by weight of tricyclo [5.2.1.0 ^2,6 ] decan-8-yl methacrylate, 20 parts by weight of vinylbenzyl 2,3-epoxypropyl ether, methacrylic acid After charging 40 parts by weight of glycidyl, 29 parts by weight of 2,3,4,5-tetrahydrofurfuryl methacrylate, and 3 parts by weight of bis (pyrazol-1-yl-thiocarbonyl) disulfide (molecular weight control agent), nitrogen substitution was performed. Stirring was started gently. The temperature of the solution was raised to 70 ° C., and this temperature was maintained for 4 hours to obtain a polymer solution containing the copolymer [a-4].
The copolymer [a-4] had a weight average molecular weight (Mw) in terms of polystyrene of 8,500 and a molecular weight distribution (Mw / Mn) of 1.5. The solid content concentration of the polymer solution obtained here was 32.7% by weight.

Example 1
[Preparation of radiation-sensitive resin composition]
As component [A], the solution of copolymer (A-1) obtained in Synthesis Example 1 is 100 parts by weight (solid content) as copolymer (A-1), and 4,4 ′ as component [B]. -[1- {4- (1- [4-Hydroxyphenyl] -1-methylethyl) phenyl} ethylidene] bisphenol-1,2-naphthoquinonediazide-5-sulfonic acid ester, 30 parts by weight, C] component is mixed with 1 part by weight of benzyl (4-hydroxyphenyl) (methyl) sulfonium hexafluorophosphate, and [G] component is mixed with 5 parts by weight of γ-methacryloyloxypropyltrimethoxysilane, with a solid content of 30% by weight. And dissolved in propylene glycol methyl ether acetate, and filtered through a Millipore filter having a pore size of 0.5 μm to obtain a composition solution (S- ) Was prepared.

Evaluation of Storage Stability The composition solution (S-1) was heated in an oven at 40 ° C. for 1 week, and evaluated by the rate of change in viscosity before and after heating. At this time, when the viscosity change rate is less than 5%, the storage stability is good, and when it is 5% or more, the storage stability is poor. The evaluation results are shown in Table 1.

Evaluation as interlayer insulation film (1) Evaluation of sensitivity The radiation sensitive resin composition prepared above was applied onto a silicon substrate using a spinner, and prebaked on a hot plate at 90 ° C. for 2 minutes. A 3.0 μm coating film was formed. The obtained coating film was exposed through a pattern mask having a predetermined pattern with a PLA-501F exposure machine (extra-high pressure mercury lamp) manufactured by Canon Inc., and then exposed to a concentration of 0.4. Development was carried out with a weight% tetramethylammonium hydroxide aqueous solution at 25 ° C. for 90 seconds. The substrate was washed with running ultrapure water for 1 minute and dried to form a pattern on the silicon substrate. At this time, the exposure amount necessary for completely dissolving the 3.0 μm line-and-space (10 to 1) space pattern was examined. When this value was evaluated as sensitivity, it was 550 J / m ² . It can be said that the sensitivity is good when this value is 600 J / m ² or less.

(2) Evaluation of resolution After apply | coating composition solution (S-1) on the glass substrate using the spinner, the prebaking temperature was changed with 80, 90, and 100 degreeC, and the coating film in each temperature was formed. The standing time on the hot plate was 3 minutes each.
Next, the obtained coating film at each temperature was exposed to ultraviolet light having an intensity of 100 W / m ^{2 at} a wavelength of 365 nm for 15 seconds through a photomask having a predetermined pattern. Thereafter, development was performed with a 0.5 wt% tetramethylammonium hydroxide aqueous solution at 25 ° C. for 1 minute, followed by washing with pure water for 1 minute to remove unnecessary portions and form a pattern.
Next, the formed pattern is exposed to ultraviolet rays having an intensity of 100 W / m ² at a wavelength of 365 nm for 30 seconds, and then cured by heating for 60 minutes in an oven at 220 ° C., thereby forming a patterned thin film having a thickness of 3 μm. Got.
With respect to the patterned thin film obtained at each temperature, the case where the extraction pattern (5 μm × 5 μm hole) could be resolved was evaluated as ◯, and the case where it was not resolved was evaluated as ×. The evaluation results are shown in Table 1.

(3) Evaluation of heat-resistant dimensional stability A patterned thin film formed at a prebake temperature of 80 ° C was heated in an oven at 220 ° C for 60 minutes, and the rate of change in film thickness before and after heating was measured and evaluated. At this time, the heat-resistant dimensional stability is good when the film thickness change rate is within 5%, and the heat-resistant dimensional stability is poor when it exceeds 5%. The evaluation results are shown in Table 1.

(4) Transparency evaluation The transmittance at a wavelength of 400 nm of a patterned thin film formed at a prebake temperature of 80 ° C. was measured using a spectrophotometer (150-20 type double beam (manufactured by Hitachi, Ltd.)). And evaluated. At this time, it can be said that transparency is poor when it is less than 93%. The evaluation results are shown in Table 1.

(5) Evaluation of adhesion The adhesion of the patterned thin film formed at a pre-baking temperature of 80 ° C to the substrate was evaluated by a cross-cut peel test after a pressure cooker test (120 ° C, humidity 100%, 4 hours). Table 1 shows the number of grids remaining in 100 grids at this time. When the grid is 100, the adhesion is good.

(6) Evaluation of voltage holding ratio On a soda glass substrate on which a SiO ₂ film for preventing elution of sodium ions is formed on the surface and ITO (indium-tin oxide alloy) electrodes are deposited in a predetermined shape, a spinner is used. The radiation-sensitive resin composition prepared above was applied and pre-baked in a clean oven at 90 ° C. for 10 minutes to form a coating film having a thickness of 2.0 μm. Next, using a high-pressure mercury lamp, the coating film was exposed to radiation containing wavelengths of 365 nm, 405 nm, and 436 nm at an exposure dose of 2,000 J / m ² without using a photomask. Further, post-baking was performed at 230 ° C. for 30 minutes to form a cured film.
Next, the substrate having this cured film and a soda glass substrate on which ITO electrodes are deposited in a predetermined shape on the surface are opposed to each other, and a sealing agent in which 0.8 mm glass beads are mixed on four sides leaving a liquid crystal injection port. The liquid crystal cell was produced by sealing the liquid crystal injection port after injecting and using liquid crystal MLC6608 (trade name) manufactured by Merck.
This liquid crystal cell is placed in a constant temperature layer of 60 ° C., and a liquid crystal voltage holding voltage measurement system VHR-1A type (product name) manufactured by Toyo Technica is used as a square wave with a voltage of 5.5 V and a measurement frequency of 60 Hz. When the voltage holding ratio was measured, the voltage holding ratio was 98%. The results are shown in Table 1.
Here, the voltage holding ratio is a value obtained by the following equation (2).

Voltage holding ratio (%) = (potential difference of liquid crystal cell after 16.7 milliseconds) / (voltage applied at 0 milliseconds) × 100 (2)
The lower the value of the voltage holding ratio of the liquid crystal cell, the higher the possibility of causing a problem called “burn-in” when forming the liquid crystal panel. It can be said that the higher the voltage holding ratio, the higher the reliability of the liquid crystal panel.

Evaluation as microlens (7) Formation of microlens The composition solution (S-1) was applied to a 6-inch silicon substrate using a spinner so that the film thickness after drying was 2.5 μm, and then 70 ° C. Was pre-baked on a hot plate for 3 minutes to form a coating film.
Next, the obtained coating film was exposed to ultraviolet rays having an intensity at a wavelength of 436 nm of 100 W / m ² through a photomask having a predetermined pattern while changing the exposure amount. Thereafter, development was carried out with a 2.38 wt% tetramethylammonium hydroxide aqueous solution at 25 ° C. for 1 minute, followed by washing with pure water for 1 minute, whereby unnecessary portions were removed to obtain a patterned thin film.
Next, the obtained patterned thin film was post-exposed for 30 seconds with ultraviolet light having an intensity of 100 W / m ² at a wavelength of 436 nm, then heated in an oven at 160 ° C. for 60 minutes, and further heated in an oven at 230 ° C. for 10 minutes. And the pattern was melt-flowed to form a microlens.

(8) Evaluation of sensitivity For the obtained microlens, the minimum exposure capable of resolving the space line width (0.08 μm) of the line and space pattern (10 to 1) having a line line width of 0.8 μm. The amount was evaluated. It can be said that the sensitivity is good when this value is 800 J / m ² or less. The evaluation results are shown in Table 2.

(9) Evaluation of heat-resistant discoloration A patterned thin film was obtained in the same manner as in “Formation of microlenses” except that a glass substrate was used instead of the silicon substrate.
Next, the glass substrate having the patterned thin film was heated in an oven at 250 ° C. for 1 hour, and evaluated by the change rate of transmittance at a wavelength of 400 nm before and after heating. At this time, when the rate of change in transmittance is less than 5%, the heat discoloration is good, and when it exceeds 5%, the heat discoloration is poor. The evaluation results are shown in Table 2.

(10) Evaluation of Adhesiveness A patterned thin film was obtained in the same manner as in “Formation of microlenses”.
Next, for the silicon substrate having the patterned thin film, the adhesion of the patterned thin film to the substrate was evaluated by a cross-cut peel test after a pressure cooker test (120 ° C., humidity 100%, 4 hours). Table 2 shows the number of grids remaining in 100 grids at this time. When the grid is 100, the adhesion is good.

(11) Evaluation of solvent resistance A patterned thin film was obtained in the same manner as in “Formation of microlenses” except that a glass substrate was used instead of the silicon substrate.
Next, the glass substrate having the patterned thin film was immersed in isopropanol at 50 ° C. for 10 minutes, and the film thickness change rate before and after immersion was measured and evaluated. At this time, the solvent resistance is good when the film thickness change rate is 5% or less, and the solvent resistance is poor when it exceeds 5% or when the thin film is dissolved and the film thickness is reduced. The evaluation results are shown in Table 2.

Example 2
A composition solution was prepared and evaluated in the same manner as in Example 1 except that the solution of copolymer (A-2) was used instead of the solution of copolymer (A-1). The evaluation results are shown in Tables 1-2.

Example 3
A composition solution was prepared and evaluated in the same manner as in Example 1 except that the solution of copolymer (A-3) was used instead of the solution of copolymer (A-1). The evaluation results are shown in Tables 1-2.

Comparative Example 1
A composition solution was prepared and evaluated in the same manner as in Example 1 except that the solution of copolymer (a-1) was used instead of the solution of copolymer (A-1). The evaluation results are shown in Tables 1-2.

Comparative Example 2
A composition solution was prepared and evaluated in the same manner as in Example 1 except that the solution of copolymer (a-2) was used instead of the solution of copolymer (A-1). The evaluation results are shown in Tables 1-2.

Comparative Example 3
A composition solution was prepared and evaluated in the same manner as in Example 1 except that the solution of copolymer (a-3) was used instead of the solution of copolymer (A-1). The evaluation results are shown in Tables 1-2.

Comparative Example 4
A composition solution was prepared and evaluated in the same manner as in Example 1 except that the solution of copolymer (a-4) was used instead of the solution of copolymer (A-1). The evaluation results are shown in Tables 1-2.

From the results shown in Tables 1 and 2, the radiation sensitive resin composition containing the copolymer polymerized using the molecular weight control agent of the general formula (1) according to the present invention has good radiation sensitivity. It was found that an interlayer insulating film having sensitivity, resolution, transparency, heat-resistant dimensional properties, adhesion and voltage holding ratio, and particularly excellent radiation sensitivity was obtained. Moreover, according to the said composition, in addition to those outstanding physical properties, it turned out that the micro lens which has favorable radiation sensitivity can be formed.

Claims (9)

(A) a copolymer, (B) a radiation-sensitive resin composition containing a 1,2-quinonediazide compound, wherein (A) the copolymer is (a1) an unsaturated carboxylic acid and / or an unsaturated carboxylic acid. Containing a copolymer produced by polymerizing an acid anhydride and a monomer containing an epoxy group-containing unsaturated compound in the presence of a compound represented by the following formula (1): A radiation-sensitive resin composition.

In [Equation ^(1), Z 1 and Z ² is an alkyl group or an optionally substituted benzyl group having 4 to 18 carbon atoms independently of one another. ]   The radiation sensitive resin composition according to claim 1, wherein the copolymer (A) according to claim 1 is a copolymer produced through a step of living radical polymerization.   The (A) copolymer according to claim 1 has a polystyrene-reduced weight average molecular weight (Mw) measured by gel permeation chromatography (GPC) of 1,000 to 15,000, and measured by Mw and GPC. The radiation-sensitive resin composition according to claim 1 or 2, wherein the ratio (Mw / Mn) to the number average molecular weight (Mn) in terms of polystyrene is a copolymer having a molecular weight of 1.8 or less.   The radiation-sensitive resin composition according to claim 1, which is used for forming an interlayer insulating film. (1) The process of forming the coating film of the radiation sensitive resin composition of Claim 4 on a board | substrate,
(2) A step of irradiating at least a part of the coating film formed in step (1),
(3) A method of forming an interlayer insulating film including a step of developing the coating film irradiated with radiation in step (2), and (4) a step of heating the coating film developed in step (3).   An interlayer insulating film formed by the method according to claim 5.   The radiation-sensitive resin composition according to claim 1, 2 or 3, which is used for forming a microlens. (1) The process of forming the coating film of the radiation sensitive resin composition of Claim 7 on a board | substrate,
(2) A step of irradiating at least a part of the coating film formed in step (1),
(3) A method of forming a microlens including a step of developing the coating film irradiated with radiation in step (2), and (4) a step of heating the coating film developed in step (3).   A microlens formed by the method of claim 8.