JP2018197325A - Resist resin - Google Patents

Abstract

To provide a resist resin that prevents the occurrence of residues during development, and yields a pattern with good adhesion.SOLUTION: The present invention provides a resist resin in which: the content of a monomer (A) represented by formula (1) is 1-40 mol%; the content of a monomer (B) having a carboxyl group is 5-40 mol%; the content of another copolymerizable monomer (C) is 20-94 mol%; and the weight average molecular weight is 3,000-100,000 (Ris H or methyl; Ris H, methyl or ethyl; Ris C1-18 alkyl).SELECTED DRAWING: None

Description

  The present invention relates to a resist resin capable of suppressing the generation of residues during development and obtaining a pattern with good adhesion.

  In recent years, photoresist materials have been widely applied, and have become microfabricated materials that are indispensable for manufacturing processes or processing processes of electronic products such as televisions and smartphones. Such a resist material is patterned by developing a difference in solubility in an alkaline solution between an exposed area and an unexposed area by irradiation with active energy rays using a mask. Next, a pattern having a predetermined shape is formed by dissolving the unexposed portion with an alkaline solution, and further removing and curing the solvent by heating.

  A resist material in which the solubility of the active energy ray irradiated part is lowered is particularly referred to as a negative resist. Since negative resists can be expected to improve mechanical strength and the like based on curing with active energy rays, they are applied as permanent resists such as solder resists for printed wiring board materials and color filter protective films for liquid crystal displays.

  In recent years, with the miniaturization of electronic products and the miniaturization of integrated circuits, improvement in resist performance is strongly desired. The resist material is removed by dissolving unnecessary portions with an alkaline solution, but there may be a case where a residual residue is generated without being sufficiently removed. Due to the miniaturization and miniaturization of electronic devices, a small amount of residue that has not been a problem until now may adversely affect the characteristics, and the reduction of the residue is required. However, when the residue is reduced, the adhesiveness of the cured product tends to be reduced. For this reason, both reduction of the residue and adhesiveness are required.

  As a method for reducing adhesion during development with good adhesion, Patent Document 1 discloses a method in which a silane coupling agent having an isocyanate group or an amino group is added as a resist resin composition. Patent Document 2 discloses a method of adding a silicon compound containing a mercapto group to a resist resin composition.

JP 2010-33027 A Japanese Patent Laid-Open No. 2006-191884

  In Patent Documents 1 and 2, adhesion and development residue reduction are attempted by adding the above-described components. However, a known compound is used as the resist resin which is the main component of the resist resin composition, and the characteristics of the resist resin have not been improved.

  The present invention has been made based on the above circumstances, and an object of the present invention is to provide a resist resin capable of suppressing the generation of residues during development and obtaining a pattern with good adhesion.

  As a result of studies to solve the above problems, the present inventor has found that a resist resin comprising a monomer having a specific structure having a urea structure can solve the above problems.

（式（１）中、
Ｒ^１は水素原子またはメチル基を示し、
Ｒ^２は水素原子、メチル基またはエチル基を示し、
Ｒ^３は炭素数１〜１８のアルキル基を示す。） That is, the present invention is as follows.
The content ratio of the monomer (A) represented by the following general formula (1) is 1 mol% to 40 mol%, the content ratio of the monomer (B) having a carboxyl group is 5 mol% to 40 mol%, etc. A resist resin characterized in that the copolymerizable monomer (C) has a content of 20 to 94 mol% and a weight average molecular weight of 3,000 to 100,000.

(In the formula (1),
R ¹ represents a hydrogen atom or a methyl group,
R ² represents a hydrogen atom, a methyl group or an ethyl group,
R ³ represents an alkyl group having 1 to 18 carbon atoms. )

  According to the resist resin of the present invention, it is possible to suppress the generation of residues during development and obtain a pattern with good adhesion.

Embodiments of the present invention will be described below.
[Monomer (A)]
The monomer (A) used in the present invention is represented by the following general formula (1).

In Formula (1), R ¹ is a hydrogen atom or a methyl group, and a methyl group is particularly preferable from the viewpoint of ease of polymerization.
R ² represents a hydrogen atom, a methyl group or an ethyl group, and a hydrogen atom is particularly preferable.
R ³ is an alkyl group having 1 to 18 carbon atoms. Examples of the alkyl group having 1 to 18 carbon atoms include methyl group, ethyl group, propyl group, isopropyl group, n-butyl group, iso-butyl group, tert-
Examples thereof include a butyl group, an n-hexyl group, an n-octyl group, a 2-ethylhexyl group, a decyl group, a dodecyl group, and a stearyl group. From the viewpoint of ease of synthesis and adhesion, R ³ has 2 carbon atoms. 12 is preferable and 3-6 is more preferable.

(Monomer (B))
Examples of the monomer (B) having a carboxyl group include acrylic acid, methacrylic acid, crotonic acid, maleic acid, fumaric acid, citraconic acid, mesaconic acid, itaconic acid, and the like. Acrylic acid and methacrylic acid are preferred because of their availability. The number of carboxyl groups that the monomer (B) has is preferably 2 or less, and more preferably 1. Moreover, a monomer (B) may be used individually by 1 type, and may use 2 or more types together.

(Monomer (C))
The other copolymerizable monomer (C) is not particularly limited as long as it is a monomer that can be copolymerized with the monomer (A) or the monomer (B), and may include one or more kinds. However, (meth) acrylic acid ester monomers and aromatic vinyl compounds are preferred.

  Examples of the (meth) acrylate monomer include, for example, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, pentyl (meth) acrylate, ( Hexyl (meth) acrylate, cyclohexyl (meth) acrylate, heptyl (meth) acrylate, octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, nonyl (meth) acrylate, decyl (meth) acrylate , Dodecyl (meth) acrylate, phenyl (meth) acrylate, benzyl (meth) acrylate, 2-methoxyethyl (meth) acrylate, 3-methoxybutyl (meth) acrylate, (meth) acrylic acid 2-hydroxyethyl, hydroxypropyl (meth) acrylate, hydroxy (meth) acrylate Examples include chill, stearyl (meth) acrylate, ethylene oxide adduct of (meth) acrylic acid, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, (meth) acrylic acid Preferred are butyl, cyclohexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, and benzyl (meth) acrylate.

  Aromatic vinyl compounds include styrene, α-methylstyrene, p-methylstyrene, m-methylstyrene, o-methylstyrene, p-ethylstyrene, m-ethylstyrene, o-ethylstyrene, t-butylstyrene, chloro. Styrene, hydroxystyrene, t-butoxystyrene, vinyltoluene, vinylnaphthalene and the like can be mentioned, and styrene is preferable.

  When the total amount of the monomers (A), (B) and (C) is 100 mol%, the content ratio of the monomer (A) is 1 to 40 mol%, preferably 2 to 30 mol%, more preferably Is 3 to 20 mol%. Moreover, the content rate of the monomer (B) which has a carboxyl group is 5-40 mol%, Preferably it is 7-30 mol%, More preferably, it is 10-20 mol%. The content ratio of the other copolymerizable monomer (C) is 20 to 94 mol%, preferably 40 to 91 mol%, more preferably 60 to 87 mol%. By setting the content ratio of the monomers (A) to (C) to the above ratio, generation of residues during development can be suppressed, a pattern with good adhesion can be obtained, and resist characteristics such as alkali developability Can be satisfied.

[Resist resin]
The weight average molecular weight of the resist resin can be determined in terms of polystyrene using gel permeation chromatography (GPC), and is 3,000 to 100,000, preferably 4,000 to 50,000, more preferably. 5,000 to 30,000. If the weight average molecular weight of the resist resin is too low, the adhesion is insufficient, and if the weight average molecular weight is too high, resist properties such as developability may be deteriorated.

[Method for Producing Monomer (A)]
The monomer (A) of the present invention is a monomer having a urea bond.
The monomer (A) can be obtained, for example, by reacting an isocyanate group-containing monomer with an amine compound.

  As the isocyanate group-containing monomer, 2- (meth) acryloyloxyethyl isocyanate is preferable, and 2-methacryloyloxyethyl isocyanate is more preferable from the viewpoint of polymerization stability.

The amine compound is preferably a primary amine compound or a secondary amine compound, and more preferably a primary amine compound.
Examples of the primary amine compound include ethylamine, n-propylamine, isopropylamine, n-butylamine, sec-butylamine, tert-butylamine, n-pentylamine, n-hexylamine, n-octylamine, and 2-ethylhexyl. Examples include amine, decylamine, dodecylamine, stearylamine, cyclohexylamine, benzylamine, and aniline, and these can be used alone or in combination of two or more. Among these, n-butylamine, n-pentylamine, n-hexylamine, n-octylamine, 2-ethylhexylamine, decylamine, and dodecylamine are preferable, and n-butylamine is more preferable from the viewpoint of adhesion of the resist resin.

  Examples of the secondary amine compound include diethylamine, dipropylamine, dibutylamine, diisopropylamine, dioctylamine (di-n-octylamine, di-2-ethylhexylami, piperidine, morpholine, and the like. Can be used alone or in combination of two or more.

  The reaction of the isocyanate group-containing monomer and the amine compound can be carried out by a known method by mixing the both and raising the temperature as desired. Further, if necessary, a catalyst may be added. For example, a known catalyst such as a tin catalyst such as stannous octoate or dibutyltin dilaurate, or an amine catalyst such as triethylenediamine can be used. This reaction is desirably performed at a temperature of 5 to 100 ° C, preferably 20 to 80 ° C. The above reaction may use a solvent, and can be performed in the presence of acetone, methyl isobutyl ketone, ethyl acetate, butyl acetate, toluene, xylene, tetrahydrofuran, or the like.

[Method for producing resist resin]
Next, a method for producing the resist resin of the present invention will be described.
The polymer in the present invention can be obtained by radical polymerization of a monomer mixture. The polymerization can be performed by a known method. For example, solution polymerization, suspension polymerization, emulsion polymerization and the like can be mentioned, but solution polymerization is preferable in terms of easy adjustment of the weight average molecular weight of the copolymer within the above range.

A well-known thing can be used for a polymerization initiator. For example, di (4-t-butylcyclohexyl) peroxydicarbonate, organic peroxides such as 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanoate, 2,2′-azobis Examples thereof include azo polymerization initiators such as isobutyronitrile. These polymerization initiators may be used alone or in combination of two or more.
The usage-amount of a polymerization initiator can be suitably set according to the combination of the monomer to be used, reaction conditions, etc.

  In addition, when charging the polymerization initiator, for example, the whole amount may be charged all at once, a part may be charged all at once and the rest may be dropped, or the whole amount may be dropped. Moreover, it is preferable to add a polymerization initiator together with the monomer because the control of the reaction is easy, and it is preferable to add a polymerization initiator even after the monomer is added because the residual monomer can be reduced.

  As a polymerization solvent used in the solution polymerization, a solvent in which a monomer and a polymerization initiator are dissolved can be used. Specifically, methanol, ethanol, 1-propanol, acetone, methyl ethyl ketone, propylene glycol monomethyl ether, etc. Can be mentioned.

  As for the density | concentration of the monomer (total amount) with respect to a polymerization solvent, 10-60 mass% is preferable, Most preferably, it is 20-50 mass%. If the concentration of the monomer mixture is too low, the monomers are likely to remain, and the molecular weight of the resulting copolymer may be reduced. If the concentration of the monomer is too high, it may be difficult to control heat generation.

  When the monomer is added, for example, the whole amount may be charged all at once, a part may be charged all at once and the rest may be dropped, or the whole amount may be dropped. From the viewpoint of easy control of heat generation, it is preferable to charge a part and drop the rest, or drop the whole amount.

  The polymerization temperature depends on the type of the polymerization solvent, and is, for example, 50 ° C to 110 ° C. The polymerization time depends on the type of polymerization initiator and the polymerization temperature. For example, when di (4-t-butylcyclohexyl) peroxydicarbonate is used as the polymerization initiator, the polymerization temperature is set to 70 ° C. A suitable time is about 6 hours.

  By performing the above polymerization reaction, the resist resin according to the present invention is obtained. The obtained resist resin may be used as it is, or may be isolated by filtering or purifying the reaction solution after the polymerization reaction.

Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples.
Table 1 below shows the structure and abbreviation of the monomer (A).

(Synthesis Example 1: Monomer A1)
In a 300 mL flask equipped with a stirrer, thermometer, cooler, dropping funnel and air introduction tube, 51.2 g of 2-methacryloyloxyethyl isocyanate (“Karenz MOI” manufactured by Showa Denko KK), 40 g of tetrahydrofuran, 0.012 g of methoquinone Was charged. Air was introduced into the flask, and 24.1 g of n-butylamine was added dropwise over 1 hour while maintaining the internal temperature at 40 ° C. Then, after aging at 40 ° C. for 2 hours, tetrahydrofuran was distilled off under reduced pressure at 60 ° C. to obtain monomer A1 (yield 92%).

(Synthesis Example 2: Monomer A2)
In a 300 mL flask equipped with a stirrer, thermometer, cooler, dropping funnel and air inlet tube, 46.6 g of 2-acryloyloxyethyl isocyanate (“Karenz AOI” manufactured by Showa Denko KK), 40 g of tetrahydrofuran, 0.012 g of methoquinone Was charged. Air was introduced into the flask, and 24.1 g of n-butylamine was added dropwise over 1 hour while maintaining the internal temperature at 40 ° C. Then, after aging at 40 ° C. for 2 hours, tetrahydrofuran was distilled off under reduced pressure at 60 ° C. to obtain monomer A2 (yield 90%).

(Synthesis Example 3: Monomer A3)
A 300 mL flask equipped with a stirrer, thermometer, cooler, dropping funnel and air inlet tube was charged with 46.6 g of 2-acryloyloxyethyl isocyanate (“Karenz MOI” manufactured by Showa Denko KK), 40 g of tetrahydrofuran, 0.012 g of methoquinone. Was charged. Air was introduced into the flask, and 61.1 g of n-dodecylamine was added dropwise over 1 hour while maintaining the internal temperature at 40 ° C. Then, after aging at 40 ° C. for 2 hours, tetrahydrofuran was distilled off under reduced pressure at 60 ° C. to obtain monomer A3 (yield 90%).

(Polymerization Example 1: Resist Resin 1)
Into a 1 L separable flask equipped with a stirrer, thermometer, cooler, dropping funnel and nitrogen introducing tube, 350 g of propylene glycol monomethyl ether was charged, and the inside of the flask was purged with nitrogen to make a nitrogen atmosphere. Monomer A1
16.9 g, 37.1 g of acrylic acid (“Acrylic acid” manufactured by Nippon Shokubai Co., Ltd.), 340.8 g of cyclohexyl methacrylate (“Blenmer CHMA” manufactured by NOF Corporation), and 50 g of propylene glycol monomethyl ether And a polymerization initiator solution in which 10.4 g of 2,2′-azobis (2,4-dimethylvaleronitrile) (product name: V-65 (manufactured by Wako Pure Chemical Industries, Ltd.)) was mixed was prepared.

  The temperature in the reaction vessel was raised to 75 ° C., and the monomer solution and the polymerization initiator solution were simultaneously added dropwise over 3 hours. Then, it was made to react at 75 degreeC for 3 hours, and the propylene glycol monomethyl ether solution of the resist resin 1 was obtained.

(Polymerization Example 2: Resist Resin 2)
To the monomer solution, 233.9 g of monomer A1, 39.0 g of methacrylic acid (“MAA” manufactured by Kuraray Co., Ltd.), 117.0 g of methyl methacrylate (“MMA monomer” manufactured by Kuraray Co., Ltd.), and the initiator amount of the polymerization initiator solution Resin Resin 2 was obtained in the same manner as in Polymerization Example 1 except that was changed to 23.3 g.

(Polymerization Example 3: Resist Resin 3)
Resist was prepared in the same manner as in Polymerization Example 1 except that the monomer solution was changed to 55.7 g of monomer A2, 37.5 g of acrylic acid, 305.9 g of cyclohexyl methacrylate, and the initiator amount of the polymerization initiator solution was changed to 1.9 g. Resin 3 was obtained.

(Polymerization Example 4: Resist Resin 4)
The monomer solution was changed to 11.6 g of monomer A3, 77.2 g of methacrylic acid, 297.1 g of styrene (“NS styrene” manufactured by NS Styrene Monomer Co., Ltd.), and the initiator amount of the polymerization initiator solution was changed to 4.2 g. Obtained Resist Resin 4 in the same manner as in Polymerization Example 1.

(Polymerization example 5: resist resin 5)
The same procedure as in Polymerization Example 1 except that the monomer solution was changed to 22.8 g of acrylic acid, 158.1 g of methyl methacrylate, 212.5 g of cyclohexyl methacrylate, and the initiator amount of the polymerization initiator solution was changed to 13.3 g. Resist resin 5 was obtained.

(Polymerization Example 6: Resist resin 6)
Resist resin in the same manner as in Polymerization Example 1 except that the monomer solution was changed to 49.3 g of methallylic acid, 95.6 g of methyl methacrylate, 238.6 g of styrene, and the initiator amount of the polymerization initiator solution was changed to 33.2 g. 6 was obtained.

(Measurement of weight average molecular weight)
The weight average molecular weight (Mw) was determined under the following conditions using gel permeation chromatography (GPC).
Apparatus: manufactured by Tosoh Corporation, HLC-8220
Column: manufactured by shodex, LF-804
Standard substance: Polystyrene Eluent: THF (tetrahydrofuran)
Flow rate: 1.0 ml / min
Column temperature: 40 ° C
Detector: RI (differential refractive index detector)

[Evaluation of developability]
A diluted solution prepared by mixing 10 g of a resist resin solution with 10 g of propylene glycol monomethyl ether was spin-coated on a silicon wafer and dried at 120 ° C. to obtain a resin film having a thickness of 5 μm. This silicon wafer was immersed in a 2.4% tetramethylammonium hydroxide aqueous solution for 2 minutes. The immersed silicon wafer was visually observed to evaluate the presence or absence of the polymer. The case where the resist resin did not remain was marked with ◯, and the case where it remained was marked with x.

[Evaluation of development residue]
10 g of resist resin solution, 1.5 g of dipentaerythritol hexaacrylate (“Light Acrylate DPE-6A” manufactured by Kyoeisha Chemical Co., Ltd.), 3 g of bisphenol A type epoxy resin (“JER-834” manufactured by Japan Epoxy Resin Co., Ltd.), light 0.5 g of a polymerization initiator (“IRGACURE 907” manufactured by BASF) and 40 g of propylene glycol monomethyl ether acetate were mixed to prepare a resist resin composition. It was applied onto a glass substrate by spin coating, dried at 90 ° C. for 2 minutes, and then irradiated with ultraviolet rays at an intensity of 100 to 150 mJ / cm ² through a mask with an ultrahigh pressure mercury lamp. After irradiation, it was immersed in a 0.4% tetramethylammonium hydroxide aqueous solution for 1 minute, washed with water, and cured at 230 ° C. for 1 hour.

  The obtained cured film was observed with a scanning electron microscope and evaluated by the ratio of the area of the residue in the area removed by development. Those having no residue were marked with ◎, less than 3% of the area occupied by the residue was marked with ◯, and 3% or more with x.

[Evaluation of adhesion]
A diluted solution in which 10 g of propylene glycol monomethyl ether was mixed with 10 g of the resist resin solution was applied to a PET film (A4100 film thickness 50 μm, manufactured by Toyobo Co., Ltd.) and dried at 120 ° C. for 5 minutes to obtain a resin film having a film thickness of 5 μm. The film was cut into 100 squares, a cellophane tape (manufactured by Nichiban Co., Ltd.) was attached, the cellophane tape was peeled off, and the adhesion was evaluated based on the number of remaining masses. The case where there was no peeled cell and no corner chipping was marked with ◎, the case where there was no peeled cell but corner corners was marked with ○, and the case where there was a stripped cell was marked with ×.

  As can be seen from Table 2, when the resist resin according to the examples of the present invention is used, the developability of the resist is good, the generation of residues during development can be suppressed, and a pattern with good adhesion can be obtained.

As can be seen from Table 3, in Comparative Examples 1 and 2, the monomer (A) of the present invention was not used, but a residue was generated during development.

Claims (1)

The content ratio of the monomer (A) represented by the following general formula (1) is 1 mol% to 40 mol%, the content ratio of the monomer (B) having a carboxyl group is 5 mol% to 40 mol%, etc. A resist resin characterized in that the copolymerizable monomer (C) has a content of 20 to 94 mol% and a weight average molecular weight of 3,000 to 100,000.

(In the formula (1),
R ¹ represents a hydrogen atom or a methyl group,
R ² represents a hydrogen atom, a methyl group or an ethyl group,
R ³ represents an alkyl group having 1 to 18 carbon atoms. )