TW201521083A - Method of forming resist pattern - Google Patents

Abstract

After exposing the resist film formed on a substrate using a resist composition, And Step (1) to form a pre-patterned by patterning by development, Curing the pre-patterned by irradiating one or both of ultraviolet and visible light (2), A method of forming a resist pattern having, Comprising the operation of irradiating the pre-pattern in the light cut a wavelength less than 300nm of ultraviolet and visible light, the step (2), a resist pattern forming method.

Description

Method for forming photoresist pattern

The present invention relates to a method of forming a photoresist pattern.

The priority is claimed on the basis of Japanese Patent Application No. 2013-169223, filed on Jan. 16, 2013, and the Japanese Patent Application No. 2014-089626, filed on Apr. 23, 2014, which is incorporated herein by reference. .

A technique of forming a fine pattern on a substrate and etching it as a mask to process a lower layer of the pattern (pattern forming technique) has been widely used in the manufacture of a semiconductor element or a liquid crystal display element. . The above-mentioned fine pattern is usually formed of an organic material and is formed by a technique such as a photolithography method or a nano-plasma method. For example, in the lithography method, a photoresist film is formed on a support such as a substrate by using a photoresist material containing a substrate component such as a resin, and the photoresist film is selectively exposed using radiation such as light or electron wires. The development processing or the like is performed in such a manner that the photoresist film forms a patterning pattern of a specific shape of the photoresist pattern. Subsequently, the substrate is etched by using the photoresist pattern as a mask. A semiconductor element or the like can be obtained by a process such as engraving.

However, in the past, the photoresist pattern was used as a mask, and when the substrate was processed by dry etching, the solvent remaining in the photoresist pattern was released into the etching gas atmosphere as an exhaust gas, and thus the photoresist pattern was again rendered. The type is etched to deteriorate the selectivity of the photoresist pattern to the film to be processed.

The method of sufficiently removing the solvent remaining in the photoresist pattern before dry etching is generally, for example, a method of heating the photoresist pattern at a high temperature. However, when direct and high-temperature heating is performed on the photoresist pattern formed by the pattern forming step, the photoresist pattern is easily deformed.

On the other hand, there has been proposed a method of curing the photoresist pattern to improve the heat resistance of the resist pattern. For example, a method of curing a photoresist pattern by applying ultraviolet rays or the like to a photoresist pattern formed by a pattern forming step has been disclosed (for example, Patent Document 1).

Prior technical literature [Patent Literature]

[Patent Document 1] JP-A-2008-164789

However, in the method in which the photoresist pattern is hardened by ultraviolet irradiation, the heat resistance of the photoresist pattern is still insufficient, and deformation is still generated under the required heating conditions (above 200 ° C), which is resistant to dry etching. Sex is still insufficient. In addition, when the photoresist pattern after hardening by ultraviolet irradiation is removed from the support by using a stripping solution, there is a possibility that residual residue remains on the support. question.

The present invention has been made in view of the above circumstances, and has been proposed to form a photoresist pattern having both heat resistance and dry etching resistance and excellent releasability to a support.

In order to solve the above problems, the present invention adopts the following constitution.

That is, the present invention is a method for forming a photoresist pattern which has a step of forming a pattern to form an initial pattern after being exposed to a photoresist film formed on a support using a photoresist composition. (1) A method for forming a photoresist pattern of the step (2) of curing the initial pattern by using one or both of ultraviolet rays and visible rays, wherein the step (2) is included The operation of illuminating the initial pattern is performed by blocking light of ultraviolet rays and visible light having a wavelength of less than 300 nm.

In the method for forming a photoresist pattern of the present invention, it is possible to form a photoresist pattern which has both excellent heat resistance and dry etching resistance and excellent releasability to a support.

Fig. 1 is a graph showing the relationship between the light transmittance of a resin film and a wavelength.

[Fig. 2] One of ray patterns of a metal halide lamp is exemplified.

[Fig. 3] In the light of a metal halide lamp, light having a wavelength of less than 300 nm is blocked by an optical filter, and light having a wavelength exceeding 450 nm is obtained. One of the maps of the light is illustrated.

Fig. 4 is a graph showing the temperature change of the resin film with the passage of the light irradiation time when the resin film formed of the novolak resin is irradiated with the light of the metal halide lamp shown in Fig. 2 .

[Fig. 5] In the light of the metal halide lamp shown in Fig. 3, when the light obtained by blocking the specific wavelength by the optical filter is irradiated with the resin film formed of the novolac resin, the temperature of the resin film is accompanied by the time of light irradiation. Change chart.

The method for forming a photoresist pattern of the present invention has a step of patterning a photoresist film formed on a support using a photoresist composition, and performing patterning by development to form an initial pattern ( 1) Step (2) of hardening the aforementioned initial pattern with irradiation with one or both of ultraviolet rays and visible rays. This photoresist composition will be described in detail later.

<Step (1)>

In the step (1), after the photoresist film formed on the support using the photoresist composition is exposed, it is developed to form a pattern to form an initial pattern. Further, the "initial pattern" in the present invention means the pattern of the photoresist pattern formed in the step (1).

The formation of the initial pattern can be performed, for example, in the following manner.

First, the photoresist composition is coated using a spin coater or the like. On the support, for example, at a temperature of 90 to 130 ° C, preferably for 40 to 120 seconds, preferably 60 to 90 seconds, baking (Post Apply Bake (PAB)) treatment And a photoresist film is formed.

In this case, the thickness of the photoresist film is preferably about 0.5 to 2.5 μm, preferably about 1.0 to 2.0 μm.

Next, a light source capable of generating ultraviolet rays, such as a low pressure mercury lamp, a high pressure mercury lamp, an ultrahigh pressure mercury lamp, a xenon lamp, or the like, is selectively exposed by forming a mask (mask pattern) of a specific pattern.

Next, the exposed photoresist film is subjected to development processing. For the development treatment, for example, an alkaline aqueous solution such as an aqueous solution of 1 to 10% by mass of tetramethylammonium hydroxide (TMAH) may be immersed from one end of the support to the other end, or may be placed in the center. The developing liquid droplet inlet nozzle in the vicinity of the vicinity is introduced into the entire surface of the support body.

Then, it is left to stand for about 50 to 90 seconds for development.

After the development treatment, it is preferred to carry out a washing treatment. The washing treatment is carried out, for example, by washing the developer remaining on the surface of the initial pattern with a washing liquid (pure water, an organic solvent, or the like).

Further, after the development treatment or after the washing treatment, a heating (post-baking) treatment may be applied.

After the above processing, the initial pattern can be obtained.

The support is not particularly limited, and conventionally known articles, for example, substrates for electronic components, or articles having a specific wiring pattern formed thereon may be used. More specifically, for example, germanium wafers, A substrate made of a metal such as copper, chromium, iron or aluminum, or a glass substrate. As the material of the wiring pattern, for example, copper, aluminum, nickel, gold, or the like can be used.

Further, the support may be used on the above-mentioned substrate, and an inorganic or/or organic film may be provided. Examples of the inorganic film include an inorganic antireflection film (inorganic BARC). The organic film may, for example, be an organic antireflection film (organic BARC) or an organic film such as a lower organic film in a multilayer photoresist method.

Wherein, the multilayer photoresist method refers to a photoresist pattern in which at least one organic film (lower organic film) and at least one photoresist film (upper photoresist film) are formed on the substrate to form an upper photoresist film. As a mask, a method of patterning a lower organic film can be formed, which can form a pattern of high aspect ratio. In other words, when the multilayer photoresist method is used, since the thickness of the lower organic film can be ensured, the photoresist film can be made thinner, and a fine pattern with a high aspect ratio can be formed.

In the multilayer photoresist method, a method of forming a two-layer structure of an upper photoresist film and a lower organic film (two-layer photoresist method) and a layer between the upper photoresist film and the lower organic film are basically distinguished. A method of three or more layers of the above intermediate layer (metal thin film or the like) (three-layer photoresist method).

The exposure is not particularly limited, and for example, it can be performed using radiation such as g-line, h-line, or i-line. Further, as the radiation, it is possible to use light rays such as g-line, h-line or i-line alone, or any two or more kinds of mixed rays of the above. When mixing light is used, the exposure time can be shortened. The intensity of the spectrum of each light can be appropriately selected depending on the type of the substrate.

Development treatment, not limited to alkali development, can also be used For example, solvent development of a developing solution (organic developing solution) containing an organic solvent can be selected in accordance with a photoresist composition.

The alkali developing solution used for the alkali development treatment may, for example, be a 0.1 to 10% by mass aqueous solution of tetramethylammonium hydroxide (TMAH).

The organic solvent contained in the organic developer to be used in the solvent development treatment may be any one of the known organic solvents as long as it can dissolve the substrate component in the photoresist composition. Specific examples thereof include polar solvents such as a ketone solvent, an ester solvent, an alcohol solvent, a nitrile solvent, a guanamine solvent, and an ether solvent, or a hydrocarbon solvent.

<Step (2)>

In the step (2), the initial pattern formed in the step (1) is irradiated using one or both of ultraviolet rays and visible rays to harden the initial pattern.

In the present invention, the step (2) includes an operation of illuminating the initial pattern by blocking light rays which are not blocked by ultraviolet light and visible light having a wavelength of 300 nm.

The hardening of the initial pattern in the step (2) is carried out, for example, by irradiating the initial pattern with one or both of ultraviolet rays and visible rays in a gas atmosphere of a low dew point.

In the present invention, "ultraviolet light" means that the lower limit of the wavelength range is about 1 nm, and the upper limit is the short-wavelength end of visible light. "Visible light" means that the lower limit of the wavelength range is about 360 to 400 nm, and the upper limit is 760. The meaning of light around ~830nm.

The wavelength of the light that illuminates the initial pattern is 300 nm or more, preferably 300 to 450 nm, preferably 350 to 400 nm.

When the wavelength of the light of the initial pattern is 300 nm or more, not only the surface layer side of the initial pattern but also the inside can be reached, and the entire pattern can be easily hardened. On the other hand, when it is preferably at least the upper limit value, the occurrence of radiant heat can be suppressed, and an excessive temperature rise state at the time of hardening can be suppressed.

Fig. 1 is a graph showing the relationship between light transmittance and wavelength of a resin film.

In FIG. 1, the relationship between the light transmittance of each resin film formed by the resin film of three types, ie, the acrylic resin, the polyhydroxy styrene (PHS) resin, and the novolak resin, and wavelength is shown.

As is apparent from Fig. 1, in the region where the wavelength is 300 nm or more, the light transmittance of the resin film is extremely high. When the light transmittance of the resin film is extremely high, the entire resin film can be easily cured. Thus, the heat resistance and dry etching resistance of the resin film can be improved. In addition, since the resin coating film has a relative affinity with respect to the peeling liquid used for the removal of the support, the resin film is less likely to form a residue, and therefore has excellent peelability of the support.

On the other hand, in the vicinity of the wavelength of 200 to 300 nm, since the light transmittance of the resin film is lowered to about 80%, it is easy to be cured only in the vicinity of the surface of the resin film which is irradiated with light. Therefore, the heat resistance and dry etching resistance of the resin film are not sufficient, and when the support is removed, the residue is likely to be formed.

Examples of the light source for light irradiation of one or both of ultraviolet rays and visible rays include a metal halide lamp, a high pressure mercury lamp, a low pressure mercury lamp, and an LED lamp.

Subsequently, in the present invention, for example, an optical filter capable of blocking light having a wavelength of less than 300 nm is provided for the foregoing light source, and an initial pattern is irradiated by blocking light rays of ultraviolet rays and visible light having a wavelength of not less than 300 nm.

In addition, for the foregoing light source, it is preferable to use an optical filter provided to block light having a wavelength of less than 300 nm and light having a wavelength exceeding 450 nm, and to illuminate the initial pattern of light having a wavelength of 300 to 450 nm in ultraviolet rays and visible rays. .

It is preferable to use an optical filter provided with light having a wavelength of less than 350 nm and light having a wavelength of more than 400 nm, and light having an ultraviolet wavelength of 350 to 400 nm in the visible light is irradiated to the initial pattern.

In this way, the entire initial pattern can be more easily hardened, and the pattern of the hardened photoresist pattern can be obtained.

Fig. 2 is a view showing an example of a ray spectrum of a metal halide lamp.

Fig. 3 is a view showing one of the patterns of light rays obtained by blocking light having a wavelength of less than 300 nm and light having a wavelength exceeding 450 nm through an optical filter in a light of a metal halide lamp. In the step (2), the initial pattern is preferably irradiated with light (a light having a wavelength of 300 to 450 nm) containing both ultraviolet rays and visible rays as shown in FIG.

The irradiation amount of the light irradiated to the initial pattern is preferably 10 mJ/cm ² or more, preferably about 10 to 1000 mJ/cm ² , more preferably about 50 to 1000 mJ/cm ² , and particularly preferably 150 to 500 mJ/cm ^{2 .} about. When the irradiation amount of the light that illuminates the initial pattern is preferably equal to or greater than the lower limit value, the entire initial pattern can be more easily cured.

The amount of light that can be irradiated can be controlled by adjusting the intensity of the light or adjusting the irradiation time.

The operation of irradiating the initial pattern with light of a specific wavelength range in the step (2) can be simultaneously performed during heating.

In the present invention, the temperature condition at the time of initial pattern hardening is preferably 120 ° C or less, preferably 60 to 120 ° C, more preferably 70 to 120 ° C, and 80 to 120 ° C. It is especially good, and the range of 100~120 °C is the best. When the temperature condition is below the preferred upper limit value, sublimation is less likely to occur, and machine contamination is more suppressed. On the other hand, when it is more than the lower limit, it is easier to harden the pattern.

The term "temperature condition at the time of hardening the initial pattern" as used in the present invention does not mean to consider the total heat applied to the initial pattern, but to set the temperature of the heating means such as the hot plate on which the support is disposed, and It means the temperature of the heated initial pattern itself generated by the hot plate or the like, or the radiation irradiated by the light. The temperature of the initial pattern itself can be determined, for example, using a thermoelectric pair.

Fig. 4 is a graph showing the temperature change of the resin film as the light irradiation time elapses when the resin film formed of the novolak resin is irradiated with the light of the metal halide lamp shown in Fig. 2.

4 is a graph showing a state in which the resin film is not heated, that is, a state in which the resin film is irradiated with light in a non-heated state (the relationship between the temperature of the resin film and the elapsed time) (in FIG. 4, the non-heating line).

As shown in FIG. 4, when the resin film is irradiated with the light of the metal halide lamp (without blocking with an optical filter), the resin film is not heated. The temperature of the resin film was increased by up to 75 °C.

Fig. 5 is a view showing the light obtained by blocking the light of a specific wavelength using an optical filter in the light of the metal halide lamp shown in Fig. 3, and irradiating the resin film formed of the novolak resin with the passage of the light irradiation time. Temperature change diagram of the resin film.

Fig. 5 is a view showing a case where the light is not irradiated to the resin film (the line of non-heating in Fig. 5), and a case where the resin film is irradiated with light at 90 ° C (in Fig. 5, the line of heating at 90 ° C) Curve (the relationship between the temperature of the resin film and the elapsed time).

When the resin film was not heated (in FIG. 5, the non-heating line), when the light was irradiated, it was confirmed that the temperature of the resin film was increased by 25 ° C at the highest. When compared with the case of Fig. 4, the rising temperature of the resin film was also 50 °C lower.

When the resin film is heated at 90 ° C and irradiated with light (in FIG. 5, a heating line of 90 ° C), the temperature of the resin film can be raised by light irradiation up to about 110 ° C.

For example, in the case where the resin film is heated at 90 ° C using a hot plate or the like while irradiating the light of the metal halide lamp shown in FIG. 2 (not blocked by the optical filter), the resin film can reach a very high temperature (simple It is calculated to be 90 ° C + 75 ° C), so it is thought that the heat of the resin may be deteriorated, or the machine may be contaminated due to sublimation.

In the step (2), the initial pattern is irradiated with light containing both ultraviolet rays and visible rays as shown in FIG. 3 (light blocking wavelengths of less than 300 nm, preferably re-blocking wavelengths exceeding 450 nm, by an optical filter or the like) When it is possible, it is possible to suppress a situation in which the temperature caused by the radiant heat on the initial pattern is significantly increased. With Then, in the initial pattern, the reaction such as polymerization can be performed more uniformly and hardened in the entire pattern. Therefore, it is not easy to cause thermal deterioration of the resin, or contamination of the machine due to sublimation, and the like.

In the step (2) of the present invention, the initial pattern is hardened at a dew point of -50 ° C (water concentration of 38.8 ppm mass basis) or more, and -5 ° C (water concentration of 4000 ppm mass basis) or less. It is preferably carried out in a gas atmosphere, preferably in a gas atmosphere having a dew point of -50 ° C (water concentration of 38.8 ppm by mass) or more, and -14 ° C (water concentration of 1791 ppm by mass) or less, to dew point -40 It is more preferable to carry out in a gas atmosphere of not less than °C (water concentration: 126.7 ppm by mass) or -20 °C (water concentration: 1020 ppm by mass).

When the initial pattern is at least the upper limit of the dew point (water concentration) of the gas atmosphere at the time of hardening, the pattern is more easily cured. On the other hand, when it is more than the lower limit value, workability and the like can be improved (having an advantage in that the device is easy to handle, cost, etc.).

An inert gas such as nitrogen (N ₂ ), helium (He), or argon (Ar) may be supplied as a dry gas in the gas atmosphere in which the initial pattern is hardened. By supplying the inert gas, the dew point of the gas atmosphere can be controlled, and the moisture concentration in the gas atmosphere can be adjusted.

Further, in the step (2), the oxygen concentration (mass basis) of the gas atmosphere at the time of curing the initial pattern is preferably as low as possible, and the specific oxygen concentration is preferably 1000 ppm or less, and preferably 500 ppm or less. When the oxygen concentration of the gas atmosphere at the time of curing in the initial pattern is preferably equal to or less than the upper limit, the pattern is more easily cured.

<Other steps>

The method for forming a photoresist pattern of the present invention may have steps other than the above steps (1) and (2).

For example, it may be disposed after the step (2), and the step of heat-treating the cured photoresist pattern, the heating temperature, preferably 100 ° C or higher, more preferably 100 to 300 ° C. When this heat treatment is applied, the pattern of the pattern formed in a specific shape can be surely cured, and the dry etching resistance and the like can be excellent.

(photoresist composition)

The photoresist composition used in the method for forming a photoresist pattern of the present invention can be formed by exposing and developing the exposed portion through the exposure and development in the step (1) to form an initial pattern of the positive resist composition. Or the unexposed portion is dissolved and removed to form a negative resist composition of the initial pattern.

Examples of the photoresist composition include the photoresist compositions (r1) to (r4) exemplified below.

Further, in the present specification and the scope of the present patent application, "aliphatic" is defined as a concept of relativity to aromatics, and has a meaning of a group or a compound having no aromaticity.

The "alkyl group" is a linear monovalent, branched or cyclic monovalent saturated hydrocarbon group unless otherwise specified. The alkyl group in the alkoxy group also has the same meaning.

"Alkyl", unless otherwise specified, contains linear and branched chains. A cyclic and cyclic divalent saturated hydrocarbon group.

The "halogenated alkyl group" means a group in which a part or all of a hydrogen atom in the alkyl group is substituted by a halogen atom, for example, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom or the like.

The "fluorinated alkyl group" or "fluorinated alkyl group" means a group in which a part or all of a hydrogen atom in an alkyl group or an alkyl group is substituted by a fluorine atom.

The "structural unit" means a monomer unit constituting a polymer compound (resin, polymer, copolymer).

In the case where "the substituent may be substituted", the case where the hydrogen atom (-H) is substituted by a monovalent group, and the case where the methyl group (-CH ₂ -) is substituted by a divalent group is described, .

"Exposure" is the concept of including all radiation exposure.

<Photoresist composition (r1)>

The photoresist composition (r1) is a quinone diazide ester which is an alkali-soluble resin and a specific phenol compound as a sensitivity enhancer, and is a positive-type resist obtained by dissolving in an organic solvent. Composition.

In the resist composition (r1), the alkali-soluble resin can be arbitrarily selected and used among the materials generally used as the film-forming material. For example, a phenol resin, an acrylic resin, a copolymer of styrene and acrylic acid, a polymer of hydroxystyrene, a polyvinylphenol, a poly-α-methylvinylphenol, etc., which are resins for forming a film of a positive resist composition, are known. . Among them, phenol resin is preferred as a preferred user, in which no swelling occurs. A novolak resin which is easily dissolved in an aqueous alkali solution and has excellent developability is preferred.

Examples of the phenol resin include a condensation reaction product of a phenol and an aldehyde, a condensation reaction product of a phenol and a ketone, a vinylphenol polymer, an isopropylenephenol polymer, and a hydrogen addition reaction product of the phenol resin.

The phenols in the condensation reaction product may, for example, be phenol, m-cresol, p-cresol, o-cresol, 2,3-xylenol, 2,5-xylenol, 3,5- Xylenols such as xylenol and 3,4-xylenol; m-ethylphenol, p-ethylphenol, o-ethylphenol, 2,3,5-trimethylphenol, 2,3,5-triethylphenol , 4-tert-butylphenol, 3-tert-butylphenol, 2-tert-butylphenol, 2-tert-butyl-4-cresol, 2-tert-butyl-5-cresol Alkoxyphenols such as p-methoxyphenol, m-methoxyphenol, p-ethoxyphenol, m-ethoxyphenol, p-propoxyphenol, m-propoxyphenol Ordinary propylene phenols such as o-isopropenol, p-isopropenol, 2-methyl-4-isopropenol, 2-ethyl-4-isopropenol; arylphenols such as phenol; 4'-dihydroxybiphenyl, bisphenol A, resorcinol, hydroquinone such as hydroquinone or pyrogallol.

These may be used singly or in combination of two or more.

Among these phenols, m-cresol, p-cresol, 2,5-xylenol, 3,5-xylenol, and 2,3,5-trimethylphenol are particularly preferred.

Examples of the aldehyde in the condensation reaction product include formaldehyde, para-formaldehyde, trioxane, acetaldehyde, propionaldehyde, butyl aldehyde, trimethyl acetaldehyde, acrolein, crotonaldehyde, cyclohexane aldehyde, and furfural. , furanyl acrolein, benzaldehyde, terephthalaldehyde, phenylacetaldehyde, α-phenylpropyl aldehyde, β-phenyl propyl aldehyde, o-hydroxybenzaldehyde, m-hydroxybenzaldehyde, p-hydroxyl Benzoaldehyde, o-methyl Benzoaldehyde, m-methylbenzaldehyde, p-methylbenzaldehyde, o-chlorobenzaldehyde, m-chlorobenzaldehyde, p-chlorobenzaldehyde, cinnamaldehyde, and the like.

These may be used singly or in combination of two or more.

Among these aldehydes, formaldehyde is preferred in terms of ease of availability, and in particular, it is preferred to use a combination of hydroxybenzaldehyde and formaldehyde from the viewpoint of improving heat resistance.

Examples of the ketone in the condensation reaction product include acetone, methyl ethyl ketone, diethyl ketone, and diphenyl ketone. These may be used singly or in combination of two or more.

In combination with phenols and ketones, a combination of pyrogallol and acetone is particularly preferred.

The condensation reaction product of a phenol with an aldehyde or a ketone can be produced, for example, by a known method in the presence of an acidic catalyst. As the acid catalyst, for example, hydrochloric acid, sulfuric acid, formic acid, oxalic acid, p-toluenesulfonic acid or the like can be used.

The condensation reaction product obtained in this manner is preferably subjected to treatment such as blocking the low molecular region, and it is preferred to have excellent heat resistance. For the treatment, the resin obtained by the condensation reaction may be used as a good solvent, for example, dissolved in an alcohol such as methanol or ethanol; a ketone such as acetone or methyl ethyl ketone; ethylene glycol monoethyl ether acetate, tetrahydrofuran, or the like. Then, it is injected into water to precipitate it.

In the above, in the total phenol-based repeating unit, the p-cresol-based repeating unit contains 60 mol% or more, and the m-cresol-based repeating unit contains 30 mol% or more, and the polystyrene-based weight is contained. Average molecule A novolak resin having a quantity (Mw) of 2000 to 8,000 is preferred.

When the p-cresol repeating unit is less than 60 mol%, the temperature change during heat treatment is likely to cause a change in sensitivity, and when the m-cresol repeating unit is less than 30 mol%, the sensitivity may be deteriorated. tendency.

The alkali-soluble resin may further contain other phenol-based repeating units in addition to the bisphenol-based repeating unit or the trimylphenol-based repeating unit.

Particularly preferred is a 2-component phenolic phenolic resin formed from a p-cresol repeating unit of 60 to 70 mol% and a m-cresol repeating unit of 40 to 30 mol%. The content of the condensate molecule (having two phenol nucleus molecules) is preferably a non-phenolic varnish resin having a low content of a phenol having a low molecular weight of 10% or less in the GPC (Gel. Penetration. Chromatography) method. The above-mentioned two-core body is sublimated by pre-baking or post-baking at a high temperature (for example, 130 ° C), and pollutes the ceiling of the furnace, etc., and even contaminates the glass substrate coated with the photoresist composition, thereby causing a decrease in yield. For the reason, it is preferred to use a novolac resin having a small content.

In the photoresist composition (r1), for example, a phenol compound represented by the following formula (I) can be used as the sensitivity enhancer.

[Chemical 1] [wherein R ¹ to R ⁸ each independently represent a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or a cycloalkyl group having 3 to 6 carbon atoms; R ⁹ to R ¹¹ each independently represent a hydrogen atom or an alkyl group having 1 to 6 carbon atoms; Q is a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, and is bonded to R ⁹ to form a carbon atom chain 3 to 6; a group of a cycloalkyl group or a group represented by the following formula (II).

(wherein R ¹² and R ¹³ each independently represent a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or a cycloalkyl group having 3 to 6 carbon atoms; ;c denotes an integer from 1 to 3); a and b denote integers from 1 to 3; d denotes an integer from 0 to 3; and n denotes an integer from 0 to 3.

As a sensitivity enhancer in the photoresist composition (r1), for example, tris(4-hydroxyphenyl)methane, bis(4-hydroxy-3-methylphenyl)-2-hydroxyphenylmethane, bis ( 4-hydroxy-2,3,5-trimethylphenyl)-2-hydroxyphenylmethane, bis(4-hydroxy-3,5-dimethylphenyl)-4-hydroxyphenylmethane, bis ( 4-hydroxy-3,5-dimethylphenyl)-3-hydroxyphenylmethane, bis(4-hydroxy-3,5-dimethylphenyl)-2-hydroxyphenylmethane, bis(4- Hydroxy-2,5-dimethylphenyl)-4-hydroxyphenylmethane, bis(4-hydroxy-2,5-dimethylphenyl)-3-hydroxyphenylmethane, bis(4-hydroxy- 2,5-Dimethylphenyl)-2-hydroxyphenylmethane, bis(4-hydroxy-3,5-dimethylphenyl)-3,4-dihydroxyphenylmethane, bis(4-hydroxyl -2,5-dimethylphenyl)-3,4-dihydroxyphenylmethane, bis(4-hydroxy-2,5-dimethylphenyl)-2,4-dihydroxyphenylmethane, double (4-hydroxyphenyl)-3-methoxy-4-hydroxyphenylmethane, bis(5-cyclohexyl-4-hydroxy-2-methylphenyl)-4-hydroxyphenylmethane, bis (5 -cyclohexyl-4-hydroxy-2-methylphenyl)-3-hydroxyphenylmethane, bis(5-cyclohexyl-4-hydroxy-2-methylphenyl)-2-hydroxyphenylmethane, double (5-cyclohexyl-4-hydroxy- 2-methylphenyl)-3,4-dihydroxyphenylmethane, 1-[1-(4-hydroxyphenyl)isopropyl]-4-[1,1-bis(4-hydroxyphenyl) Ethyl]benzene, 1-[1-(3-methyl-4-hydroxyphenyl)isopropyl]-4-[1,1-bis(3-methyl-4-hydroxyphenyl)ethyl] Benzene, 2-(2,3,4-trihydroxyphenyl)-2-(2',3',4'-trihydroxyphenyl)propane, 2-(2,4-dihydroxyphenyl)-2 -(2',4'-dihydroxyphenyl)propane, 2-(4-hydroxyphenyl)-2-(4'-hydroxyphenyl)propane, 2-(3-fluoro-4-hydroxyphenyl) -2-(3'-fluoro-4'-hydroxyphenyl)propane, 2-(2,4-dihydroxyphenyl)-2-(4'-hydroxyphenyl)propane, 2-(2,3, 4-trihydroxyphenyl)-2-(4'-hydroxyphenyl)propane, 2-(2,3,4-trihydroxyphenyl)-2-(4'-hydroxy-3',5'-di Methylphenyl)propane, bis(2,3,4-trihydroxyphenyl)methane, double (2,4-dihydroxyphenyl)methane, 2,3,4-trihydroxyphenyl-4'-hydroxyphenylmethane, 1,1-bis(4-hydroxyphenyl)cyclohexane, 2,4 - Bis[1-(4-hydroxyphenyl)isopropyl]-5-hydroxyphenol and the like.

Among these, in view of the particularly excellent sensitivity enhancement effect, bis(4-hydroxy-3-methylphenyl)-2-hydroxyphenylmethane, bis(4-hydroxy-2,3, 5-trimethylphenyl)-2-hydroxyphenylmethane, 2,4-bis[1-(4-hydroxyphenyl)isopropyl]-5-hydroxyphenol, 1,1-di(4-hydroxyl Phenyl)cyclohexane, 1-[1-(4-hydroxyphenyl)isopropyl]-4-[1,1-bis(4-hydroxyphenyl)ethyl]benzene, etc. are preferred.

The sensitivity enhancer may be used singly or in combination of two or more.

The content of the sensitivity enhancer is preferably 5 to 25 parts by mass, more preferably 10 to 20 parts by mass, per 100 parts by mass of the alkali-soluble resin.

In the resistive composition (r1), the photosensitive component may, for example, be a quinonediazide ester (photosensitive component 1) represented by the following formula (III) or a formula represented by the following formula (IV). An oxime diazide ester (photosensitive component 2), an esterified product of a phenol compound represented by the above formula (I) and a 1,2-naphthoquinonediazide-5 (or 4)-sulfonate compound.

[Chemical 3] [In the formula (III), R ¹⁴ independently represents an alkyl group having 1 to 5 carbon atoms, D independently represents a hydrogen atom, or 1,2-naphthoquinonediazide-5-sulfonyl group, and at least one of D represents 1,2-naphthoquinonediazide-5-sulfonyl, wherein l, m each independently represent 1 or 2. In the formula (IV), the plural D each independently represents a hydrogen atom, or a 1,2-naphthoquinonediazide-5-sulfonyl group, and at least one of D is 1,2-naphthoquinonediazide-5. -sulfonyl].

The average esterification ratio of the photosensitive component 1 is preferably from 40 to 60%, preferably from 45 to 55%. When the average esterification ratio is less than 40%, film reduction after development tends to occur, and the residual film ratio is liable to lower. On the other hand, when it exceeds 60%, the sensitivity tends to deteriorate remarkably.

Photosensitive component 1, from the viewpoint of producing a photoresist composition having excellent sensitivity, resolution, linearity, etc., in a lower cost manner, using bis(2-methyl-4-hydroxy-5-cyclohexylphenyl) The quinonediazide ester obtained from the 1,2-naphthoquinonediazide-5-sulfonium compound of 3,4-dihydroxyphenylmethane is preferred, and the esterification rate is preferably 50%.

The average esterification ratio of the photosensitive component 2 is preferably from 50 to 70%, preferably from 55 to 65%. When the average esterification ratio is less than 50%, film formation after development is likely to occur, and the residual film ratio is likely to be lowered. On the other hand, when it exceeds 70%, there is a tendency to lower the preservation stability.

Photosensitive component 2, the viewpoint of producing a photoresist composition having excellent sensitivity in a very inexpensive manner, using 1,2-naphthoquinonediazide of 2,3,4,4'-tetrahydroxybenzophenone- The quinone diazide ester obtained by the 5-sulfonate compound is preferred, and the esterification ratio is preferably 59%.

The photosensitive component may be used singly or in combination of two or more.

The content of the photosensitive component is preferably from 15 to 40 parts by mass, more preferably from 20 to 30 parts by mass, per 100 parts by mass of the total of the alkali-soluble resin and the sensitivity-enhancing agent.

In the photoresist composition (r1), an organic solvent, for example, a ketone such as acetone, methyl ethyl ketone, cyclohexanone, methyl isoamyl ketone or 2-heptanone; ethylene glycol, propylene glycol, and diethylene glycol; Alcohol, ethylene glycol monoacetate, propylene glycol monoacetate, diethylene glycol monoacetate, or monomethyl ether, monoethyl ether, monopropyl ether, monobutyl ether or single Polyols such as phenyl ether and derivatives thereof; dioxane-like cyclic ethers; ethyl lactate, methyl acetate, ethyl acetate, butyl acetate, methyl pyruvate, ethyl pyruvate, methoxy Esters such as methyl propionate and ethyl ethoxypropionate; benzene, toluene, xylene, methyl isobutyl ketone, methanol, ethanol, propanol, butanol, hexanol, cyclohexanol, methyl carbonate , ethyl carbonate, propyl carbonate, butyl carbonate, and the like.

The organic solvent may be used singly or in combination of two or more. can.

Among the above, propylene glycol monomethyl ether acetate (PGMEA) is used to impart excellent coating properties to the photoresist composition and to form an excellent film thickness uniformity suitable for the photoresist film on the substrate. Good.

PGMEA is preferably used as a solvent alone, and an organic solvent other than PGMEA may also be used in combination therewith. Examples of the organic solvent include ethyl lactate, γ-butyrolactone, and propylene glycol monobutyl ether.

In the resistive composition (r1), the total amount of the alkali-soluble resin, the sensitivity enhancer, and the photosensitive component is excellent in coatability to the support, and is 30% by mass or less based on the total mass of the composition. Preferably, it is preferably 20 to 28% by mass.

In this case, the amount of the organic solvent is preferably 50 to 90% by mass, preferably 65 to 85% by mass, more preferably 65 to 85% by mass, based on the amount of the additive to be used hereinafter. Good is 70~75% by mass.

In the photoresist composition (r1), an anti-halation ultraviolet absorber may be added as necessary, and for example, 2,2',4,4'-tetrahydroxybenzophenone, 4-dimethylamino group- 2',4'-dihydroxybenzophenone, 5-amino-3-methyl-1-phenyl-4-(4-hydroxyphenylazo)pyrazole, 4-dimethylamino group- 4'-hydroxyazobenzene, 4-diethylamino-4'-ethoxyazobenzene, 4-diethylaminoazobenzene, curcumin and the like.

Further, in the photoresist composition (r1), a surfactant for preventing streaks may be used, for example, FUROLATE FC-430, FC431 (trade name, manufactured by Sumitomo 3M Co., Ltd.); F-TOP EF122A, EF122B, EF122C, EF126 (trade name, manufactured by Dow Chemical Manufacturing Co., Ltd.); XR-104 (product name, manufactured by Dainippon Paint Chemical Industry Co., Ltd.), BYK-310 (product name, BAK Chemical Co., Ltd., Japan) System) and so on.

Further, in the photoresist composition (r1), it is necessary to add a storage stabilizer such as benzoquinone, naphthoquinone or p-toluenesulfonic acid; and it is necessary to add an additional resin, a plasticizer, a stabilizer, and a contrast enhancement. Conventional additives such as agents.

<Photoresist composition (r2)>

The photoresist composition (r2) is a positive-type photoresist composition containing a copolymer of a repeating unit represented by the following formula (1) and a repeating unit represented by the formula (2), and a photosensitive component.

When the photoresist film formed of the photoresist composition (r2) is used, for example, in the case of a microlens, a good microlens having excellent heat resistance and chemical resistance can be formed.

[In the formulae (1) and (2), R ⁰ each independently represents a hydrogen atom or a methyl group. R ²¹ represents a single bond or an alkylene group having 1 to 5 carbon atoms. R ²² represents an alkyl group having 1 to 5 carbon atoms. R ²³ represents a monovalent organic group having thermal crosslinkability. p represents an integer from 1 to 5, q represents an integer from 0 to 4, and p+q is 5 or less. However, the repetition of a plurality of mutually inter-R ⁰ R ²² each may be different from each other is also].

. Repeating unit represented by the general formula (1)

The repeating unit represented by the formula (1) (hereinafter also referred to as "repeating unit (1)") has alkali solubility.

In the above formula (1), R ⁰ is preferably a methyl group.

The alkyl group having 1 to 5 carbon atoms in R ²¹ , for example, methyl group, ethyl group, propyl group, isopropyl group, n-butylene group, isobutylene group, tert-butyl group, It is preferred to extend the methyl group and extend the ethyl group.

In the benzene ring of the repeating unit (1), at least one hydroxyl group is bonded.

The p indicating the number of hydroxyl groups is an integer of 1 to 5, and it is preferably 1 in terms of production. Further, in the benzene ring, the bonding position of the hydroxyl group is preferably the position of the fourth position when the bonding position of at least one "-C(=O)-OR ²¹ -" is the first position.

Further, in the benzene ring which the repeating unit (1) has, R ²² may bond a linear or branched alkyl group having 1 to 5 carbon atoms. Examples of the alkyl group include methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, tert-butyl, pentyl, isopentyl, neopentyl, etc., industrially. In particular, a methyl group or an ethyl group is preferred. q represents an integer from 0 to 4, and 0 is preferred.

The repeating unit (1) may be used alone or in combination of two or more.

In the copolymer having the repeating unit (1) and the repeating unit (2), the content of the repeating unit (1) is preferably 20 to 50 mol% based on the total of the repeating units constituting the copolymer. When it is in this range, it is easy to ensure alkali solubility at the time of development.

. Repeating unit represented by the general formula (2)

The repeating unit represented by the formula (2) (hereinafter also referred to as "repeating unit (2)") contains a thermal crosslinking group (R ²³ ).

In the above formula (2), R ⁰ is preferably a methyl group.

The alkylene group having a carbon number of 1 to 5 in R ²¹ may, for example, be a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butylene group, an isobutyl group, a tert-butyl group. Base, pentyl group, isoamyl group, neopentyl group, etc., of which, it is better to stretch methyl and ethyl.

In the above formula (2), R ²³ represents a monovalent organic group having thermal crosslinkability (hereinafter referred to as "thermal crosslinking group"). The thermally crosslinked group refers to a group which crosslinks upon heating.

R ^{23 is} preferably an organic group containing either an epoxy group or an epoxy group. Among these, R ²³ is preferably an organic group containing an epoxy group from the viewpoint of improving the crosslinking efficiency by heat treatment.

The repeating unit (2) may be used alone or in combination of two or more.

In a copolymer having a repeating unit (1) and a repeating unit (2), repeating a single The content of the position (2) is preferably from 50 to 80 mol% based on the total of the repeating units constituting the copolymer.

In the copolymer, when the content of the repeating unit (2) is at least the lower limit, the reduction in the transmittance due to the heat treatment can be reduced, and the thermosetting property can be easily ensured. When it is less than the upper limit, the generation of residue at the time of development can be more suppressed.

The copolymer having the repeating unit (1) and the repeating unit (2) may be formed by any of random polymerization or block polymerization.

As described above, when a copolymer having a repeating unit different from the repeating unit (1) and the repeating unit (2) is used, the alkali dissolution rate, the heat resistance, and the like can be easily controlled.

The mass average molecular weight of the copolymer (Mw: measured value in terms of styrene conversion by gel permeation chromatography (GPC)) is preferably 10,000 to 30,000. When the Mw of the copolymer is at least the lower limit value, the heat resistance can be improved. For example, when a microlens is formed using a copolymer, the shape of the lens can be easily maintained when the microlens is cured and sintered. On the other hand, when it is preferably at most the upper limit value, generation of residue at the time of development can be suppressed.

Further, the photoresist composition (r2) preferably contains a copolymer having a repeating unit (1) and a repeating unit (2), and a Mw of 10,000 to 30,000, which can form a higher glass transition temperature. A photoresist film having heat resistance capable of maintaining its shape even when exposed to a high temperature. Further, since the photoresist composition (r2) contains a copolymer having a repeating unit containing a thermal crosslinking group (R ²³ ), a photoresist film having higher hardness and excellent chemical resistance can be formed.

In addition to the copolymer having the above repeating unit (1) and repeating unit (2), the resist composition (r2) may be used in combination with a resin component other than the copolymer. The resin component may, for example, be an acrylic resin, a hydroxystyrene resin, a novolak resin or the like.

The photosensitive component used for the photoresist composition (r2) is the same as the photosensitive component used for the photoresist composition (r1).

The photosensitive component may be used singly or in combination of two or more.

In the photoresist composition (r2), the content of the photosensitive component is preferably in the range of 10 to 40% by mass based on the solid content of the resist composition (r2). When the content of the photosensitive component is preferably at least the lower limit value, the pattern can be favorably formed. The photoresist composition (r2) is used in the case of forming a microlens, and the lens shape can be well formed during development. On the other hand, when the content of the photosensitive component is preferably at most the upper limit value, the developability can be improved, and generation of residue at the time of development can be suppressed.

In the photoresist composition (r2), a copolymer having a repeating unit (1) and a repeating unit (2) and a component other than the photosensitive component can be used as necessary.

In the photoresist composition (r2), for example, a surfactant may be added to the viewpoint of coating properties of the support, or various additives such as a sensitizer or an antifoaming agent may be added.

The photoresist composition (r2) can be prepared by dissolving the copolymer, a photosensitive component, and other components which are necessary to be dissolved in an organic solvent. Work.

<Photoresist composition (r3)>

The photoresist composition (r3) is a chemically amplified negative-type photoresist composition containing an alkali-soluble resin and an acid generator.

In the photoresist composition (r3), an alkali-soluble resin is generally used in a resin used as a base resin of a negative-type chemically amplified photoresist composition, and a light source used for exposure is used, and any of the conventionally known components is arbitrarily Choose to use. For example, a novolac resin, a polyhydroxy styrene resin, an acrylic resin, etc. are mentioned.

For the alkali-soluble resin, a novolac resin, a polyhydroxystyrene resin, an acrylic resin, or the like may be used alone or in combination of two or more kinds.

The content of the alkali-soluble resin, for example, the photoresist composition (r3) is an alkali-soluble resin, an acid generator, and a plasticizer described later, and the total solid content of the alkali-soluble resin and the acid generator and the plasticizer. 100 parts by mass is preferably 30 to 99 parts by mass, preferably 65 to 95 parts by mass.

In the photoresist composition (r3), the acid generator is not particularly limited as long as it is a compound which generates an acid directly or indirectly via irradiation with light, and can be arbitrarily selected from conventionally known components.

The acid generator may be used singly or in combination of two or more.

In the photoresist composition (r3), the content of the acid generator is 0.01 to 5 parts by mass based on 100 parts by mass of the total solid content of the photoresist composition (r3). Preferably, it is preferably 0.05 to 2 parts by mass, more preferably 0.1 to 1 part by mass.

Among the photoresist composition (r3), an alkali-soluble resin and a component other than the acid generator can be used in accordance with necessity. For example, a plasticizer may be added in addition to the alkali-soluble resin and the acid generator. When a plasticizer is added, the occurrence of cracks can be suppressed. Examples of the plasticizer include an acrylic resin, a polyvinyl resin, and the like.

Further, in the photoresist composition (r3), a crosslinking agent may be added in addition to the alkali-soluble resin and the acid generator, or an alkali-soluble resin, an acid generator, and a plasticizer.

The crosslinking agent may, for example, be an amine compound such as melamine resin, urea resin or hydrazine. Resin, glycoluril-formaldehyde resin, succinimide-formaldehyde resin, ethylene urea-formaldehyde resin, etc., especially alkoxymethylated amine-based resin such as alkoxymethylated melamine resin or alkoxymethylated urea resin To be more suitable for the user.

In the photoresist composition (r3), a fluorine-containing polymer compound containing a structural unit having an alkali-dissociable group (preferably, an alkali-dissociable group containing a fluorine atom) may be added in addition to the above components.

The "alkali dissociable group" means an organic group which is dissociated by the action of a base. In other words, the "alkali dissociable group" is dissociated by the action of an alkali developer (for example, a 2.38 mass% TMAH aqueous solution at 23 ° C).

When the alkali dissociable group is dissociated by the action of the alkali developing solution, since the hydrophilic group can be expressed, the affinity to the alkali developing solution can be improved. That is, the fluorine-containing polymer compound is a polymer having a high hydrophobicity and having a fluorine atom. The compound also has an "alkali dissociable group", so that the affinity to the alkali developer can be improved by the action of the alkali developer. Therefore, when the negative-type photoresist composition is used, it is hydrophobic at the time of immersion exposure, so that it can be dissolved in an alkali developing solution at the time of development to form a photoresist film.

In the photoresist composition (r3), an inhibitor such as a second or tertiary amine such as triethylamine, tributylamine, dibutylamine or triethanolamine may be added in addition to the above components (Quencher); a surfactant; A functional decane coupling agent, a filler, a colorant, a viscosity modifier, an antifoaming agent, and the like as a secondary auxiliary agent.

The photoresist composition (r3) can be produced by dissolving an alkali-soluble resin, an acid generator, and other components other than necessary in an organic solvent.

<Photoresist composition (r4)>

The photoresist composition (r4) is a negative-type photoresist composition containing an alkali-soluble resin, a cationic polymerization initiator, and a sensitizer.

In the photoresist composition (r4), the alkali-soluble resin may, for example, be a polyfunctional epoxy resin. The polyfunctional epoxy resin is not particularly limited as long as it is an epoxy resin having a sufficient photo-resistance pattern of a thick film in one molecule, and examples thereof include a polyfunctional phenol. A novolak type epoxy resin, a polyfunctional o-cresol novolak type epoxy resin, a polyfunctional triphenyl novolak type epoxy resin, a polyfunctional bisphenol A novolak type epoxy resin, and the like.

Further, as the alkali-soluble resin, a photocurable base can also be used. Soluble substrate.

In the photoresist composition (r4), the cationic polymerization initiator is irradiated with excimer lasers such as ultraviolet rays, far ultraviolet rays, KrF, and ArF, X-rays, or electron beams to form a cationic portion, and the cationic portion thereof can be used as a polymerization. The compound of the initiator. The cationic polymerization initiator can be arbitrarily selected from conventionally known components.

The cationic polymerization initiator may be used singly or in combination of two or more.

In the photoresist composition (r4), the content of the cationic polymerization initiator is preferably 0.5 to 20 parts by mass based on 100 parts by mass of the alkali-soluble resin. When the content of the cationic polymerization initiator is 0.5 parts by mass or more, sufficient light sensitivity can be obtained. On the other hand, when it is 20 mass parts or less, the characteristics of the photoresist film can be improved.

In the photoresist composition (r4), the sensitizer is preferably formed of a naphthalene derivative or hydrazine or a derivative thereof which can be crosslinked with the above polyfunctional epoxy resin.

The sensitizing function of the sensitizers can make the photoresist composition more sensitive. Among them, a sensitizer containing dihydroxynaphthalene having two hydroxyl groups or hydrazine is particularly preferred. Since these sensitizers have a plurality of aromatic rings, the photoresist pattern can be made to have a high hardness.

The sensitizer may be used singly or in combination of two or more.

In the photoresist composition (r4), the content of the sensitizer is preferably from 1 to 50 parts by mass based on 100 parts by mass of the alkali-soluble resin.

In the photoresist composition (r4), components other than the alkali-soluble resin, the cationic polymerization initiator, and the sensitizer can be used as necessary.

For example, in order to further improve the hardenability of the photoresist pattern, it is preferred to use a propylene oxide derivative.

Further, in addition to the above cationic polymerization initiator, a photopolymerization initiator for a photosensitive resin composition may be used. Further, a photopolymerizable compound may be added from the viewpoint of easily causing hardening failure at the time of exposure, and it is easy to obtain sufficient heat resistance.

Further, in the photoresist composition (r4), an additive having a miscibility may be appropriately added in accordance with the intended purpose, for example, a resin, a plasticizer, a stabilizer, a colorant, or a resin added to improve the resistance of the photoresist pattern. A conventionally known component such as a coupling agent or a smoothing agent.

The photoresist composition (r4) is produced by dissolving an alkali-soluble resin, a cationic polymerization initiator, a sensitizer, and other components added as necessary, in an organic solvent.

Example

Hereinafter, the present invention will be described in more detail by way of examples, but the invention is not limited by the examples.

The photoresist composition (1) used in the present embodiment is as follows.

Photoresist composition (1):

100 parts by mass of the alkali-soluble resin described below, and 10 parts by mass of the sensitivity improving agent and 23 parts by mass of the photosensitive component were uniformly dissolved in 429 parts by mass of the organic solvent, and then a membrane filter having a pore size of 0.2 μm was used. Filter to make a photoresist composition.

Alkali-soluble resin: a cresol novolac resin having a mass average molecular weight (Mw) of 4000 obtained by a condensation reaction of oxalic acid with formaldehyde by adding a mixture of m-cresol 35 mol% and p-cresol 65 mol%. A cresol novolak resin (product name: GTR-M2, manufactured by Kyoei Chemical Industry Co., Ltd.) having a Mw of 4,500 and a phenolic nucleus having a nucleus content of about 6 mol% was obtained.

Sensitivity enhancer: a phenol compound represented by the following chemical formula (V).

Photosensitive component: Compound 1 mol represented by the following chemical formula (VIII), and 1,2-naphthoquinonediazide-5-sulfonic acid (hereinafter, referred to as "5-NQD") 2.34 mol Esterified product (esterification rate: 59 mol%).

Organic solvent: propylene glycol monomethyl ether acetate.

<evaluation>

Using the photoresist composition (1) described above, a photoresist pattern is formed in the following manner Type and conduct various assessments.

[Formation of photoresist pattern] (Example 1)

step 1):

The photoresist composition (1) was applied onto a 6-inch wafer subjected to hexamethyldioxane (HMDS) treatment using a spin coater, and subjected to 110 ° C for 90 seconds on a hot plate. As a result of prebaking and drying, a photoresist film having a film thickness of 1.5 μm was formed.

Next, exposure was performed using a specific mask pattern using an exposure apparatus (trade name G7E, manufactured by Nikon Corporation; NA0.54).

Thereafter, alkali development was carried out for 65 seconds using a 2.38 mass% aqueous solution of tetramethylammonium hydroxide "NMD-3" (trade name, manufactured by Tokyo Ohka Kogyo Co., Ltd.) at a temperature of 23 °C. As a result, an initial pattern of lines and spaces is formed.

Step (2):

Next, the initial pattern is irradiated with light containing both ultraviolet rays and visible rays, which is a light having a blocking wavelength of less than 300 nm and exceeding 450 nm, and the initial pattern is hardened.

The curing conditions using this light irradiation are as follows.

Device: Ultraviolet irradiation device (manufactured by Tokyo Ohka Kogyo Co., Ltd.).

Irradiation wavelength: 300~450nm, using a filter to block the wavelength of the metal halide light line below 300nm and over 450nm.

Irradiation amount: 150 mJ/cm ² .

The temperature at the time of initial pattern hardening (temperature of the initial pattern itself): 120 ° C, a thermoelectric pair was placed on the substrate stage, and it was measured by blocking light irradiation.

Heating temperature of the substrate machine: adjusted to 120 °C.

Gas atmosphere in the apparatus: supply N ₂ gas, Dew point -25 ° C (water concentration 600 ppm mass basis), oxygen concentration 1000 ppm mass basis.

Further, the temperature of the initial pattern itself is determined by heating through the substrate stage (hot plate) and heating by irradiation of light. In the hardening condition of the light irradiation, the temperature caused by the heat absorption of the substrate is lowered, and the temperature rise caused by the radiation of the light is affected, so that the temperature of the initial pattern itself is close to the heating temperature of the substrate machine. .

In the first embodiment, via the steps (1) and (2), a line and space photoresist pattern having a line width of 1.5 μm and a pitch width of 3.0 μm was obtained.

(Examples 2 and 3)

Except for changing the size of the mask pattern used in the step (1) of the first embodiment, the operation is performed in the same manner as in the first embodiment (step (1) and step (2)), and a photoresist pattern is obtained. type.

In the second embodiment, a photoresist pattern of a line and a space having a line width of 5.0 μm and a pitch of 10 μm was obtained.

In Example 3, a large-area photoresist pattern having a line width of more than 100 μm was produced.

(Comparative Example 1)

step 1):

Using the photoresist composition (1), the initial pattern of the line and space was obtained in the same manner as in the first embodiment.

Step (2):

Next, the initial pattern was irradiated with light containing both ultraviolet rays and visible rays (without using a filter to block the wavelength), and the initial pattern was hardened.

The curing conditions of the light irradiation are as follows.

Device: Ultraviolet irradiation device (manufactured by Tokyo Ohka Co., Ltd.).

Irradiation wavelength: 254 nm, low pressure mercury lamp.

Irradiation amount: 150 mJ/cm ² .

Heating temperature of the substrate machine: adjusted to 120 °C.

Gas atmosphere in the device: vacuum 1.5 Torr.

In addition, the temperature of the initial pattern itself cannot be measured in the vacuum chamber, but the temperature at which the initial pattern is hardened when the substrate is irradiated by the substrate table (hot plate) and heated by the irradiation of the light (initial map) The temperature of the type itself is more than 120 °C.

In Comparative Example 1, a photoresist pattern of a line and a space having a line width of 1.5 μm and a pitch width of 3.0 μm was obtained through the above operation.

(Comparative examples 2 and 3)

The photoresist pattern was obtained by performing the same operation as in Comparative Example 1 except that the size of the mask pattern used in the step (1) of the above Comparative Example 1 was changed.

In Comparative Example 2, a line-and-space resist pattern of a line width of 5.0 μm and a pitch of 10 μm was obtained.

In Comparative Example 3, a large-area photoresist pattern having a line width of more than 100 μm was obtained.

[Evaluation of heat resistance (1)]

The tantalum wafers on which the resist pattern was formed in each of Examples 1 to 3 and Comparative Examples 1 to 3 were placed on a hot plate at 130 ° C and heated for 5 minutes.

Subsequently, the state of the resist pattern after heating was observed, and the heat resistance was evaluated.

As a result, in the pattern surface and the pattern side wall of the resist pattern obtained in Comparative Examples 1 to 3, it was apparent that the photoresist pattern obtained in Examples 1 to 3 did not appear on the surface of the pattern to produce a "wrinkled turtle". Deformation and deformation of the sidewall of the pattern (hot sag).

From this, it was confirmed that the photoresist patterns obtained in Examples 1 to 3 exhibited higher heat resistance when compared with the photoresist patterns obtained in Comparative Examples 1 to 3.

Further, from this result, the photoresist pattern obtained in Examples 1 to 3 can be known, and the entire portion should be sufficiently cured until it is inside. Therefore, it is also known that it has high dry etching resistance.

[Evaluation of the peelability of the support]

In the present embodiment, the stripping liquid used for removing the photoresist pattern formed on the germanium wafer is as follows.

Water stripping solution: N-methyl-2-pyrrolidone (NMP)/H ₂ O/diethylhydroxylamine (DEHA)/monoethanolamine (MEA)/xylitol=11/42.5/8/16/22.5 (mass ratio).

Organic solvent-based stripping solution: dimethyl hydrazine (DMSO) / monoethanolamine (MEA) = 30/70 (mass ratio).

. Evaluation of the production of samples (Example 4)

Using the photoresist composition (1), the same operation as in Example 1 was carried out (step (1) and step (2)) to obtain a photoresist pattern.

(Example 5)

The same procedure as in Example 4 was carried out except that the heating temperature of the substrate stage was changed from 120 ° C to 100 ° C (the temperature at which the initial pattern was hardened was changed from 120 ° C to 100 ° C). Photoresist pattern.

(Comparative Example 4)

Using the photoresist composition (1), the same operation as in Comparative Example 1 (step (1) and step (2)) was carried out to obtain a photoresist pattern.

(Comparative Example 5)

The photoresist pattern was obtained in the same manner as in Comparative Example 4 except that the heating temperature of the substrate stage was changed from 120 ° C to 100 ° C.

(Comparative Example 6)

Using the photoresist composition (1), the initial pattern of the line and space was obtained in the same manner as in the first embodiment.

Thereafter, the initial pattern was heated at 160 ° C (post-baking), and the initial pattern was hardened to obtain a line and space photoresist pattern having a line width of 1.5 μm and a pitch width of 3.0 μm.

The evaluation of the peelability of the support was carried out in the following order.

In the first step, the tantalum wafer (evaluation sample) on which the resist pattern was obtained in each of Examples 4 and 5 and Comparative Examples 4 to 6 was cut in the thickness direction to reveal the cross section.

Step 2: The cut ruthenium wafer is immersed in a peeling liquid (water-based peeling liquid, organic solvent-based peeling liquid). At this time, the temperature of the peeling liquid was adjusted to the temperature (60 ° C, 80 ° C) as shown in Tables 1 and 2, respectively.

Sequence 3: After 2 minutes of infiltration, 5 minutes later, and 10 minutes later, the silicon wafer was taken out from the stripping solution, and air was blown to remove the attached stripping liquid.

Sequence 4: The wafer surface was observed using a microscope (SEM, 100 times), and the presence or absence of the photoresist pattern residue was confirmed and evaluated according to the following evaluation criteria.

Evaluation basis

◎: At the time when the infiltration began to 2 minutes later, the residue of the photoresist pattern was not confirmed on the wafer surface.

○: At the time when the infiltration began to 2 minutes later, the residue of the photoresist pattern was found on the wafer surface, but no residue was found at the time of 5 minutes.

△: At the time point after the start of the infiltration for 5 minutes, the residue of the photoresist pattern was found on the wafer surface, but no residue was found after 10 minutes.

×: After the infiltration began for more than 10 minutes, the residue of the photoresist pattern was still found on the wafer surface.

The evaluation results of the peelability by the support are shown in Tables 1 and 2.

According to the results shown in Tables 1 and 2, it was found that the photoresist patterns formed on the surface of the ruthenium wafer in Examples 4 and 5 were confirmed regardless of either the water-based stripping solution or the organic solvent-based stripping solution. The peelability of the photoresist pattern due to the wafer surface is higher.

[Evaluation of various effects such as temperature and gas atmosphere in the hardening of the initial pattern]

Using the photoresist composition (1), a photoresist pattern was formed in the following manner, and a dissolution test for isoamyl acetate was carried out.

(Examples 6 to 9 and Comparative Examples 7 to 8)

step 1):

Using the photoresist composition (1), except for changing the size of the mask pattern used in the step (1) of the above-described first embodiment, the same operation as in the first embodiment is performed (step (1)), The line width is 5.0μm and the pitch is wide. 10μm line and space photoresist pattern (initial pattern).

Step (2):

Next, the initial pattern is irradiated by using light containing both ultraviolet rays and visible rays (light rays obtained after blocking wavelengths of less than 300 nm and exceeding 450 nm) to perform hardening of the initial pattern, and to obtain a line on the wafer surface. A line-and-space photoresist pattern with a width of 5.0 μm and a pitch of 10 μm.

The curing conditions of the light irradiation are as follows.

Device: Ultraviolet irradiation device (manufactured by Tokyo Ohka Kogyo Co., Ltd.).

Irradiation wavelength: 300~450nm, using a filter to block the wavelength of metal halide light lines below 300nm and over 450nm.

Irradiation amount: 150 mJ/cm ² .

The curing conditions other than the above, for example, as shown in Table 3, change the temperature at the initial pattern hardening (the temperature of the initial pattern itself), the heating temperature of the substrate table, the dew point (water concentration) of the gas atmosphere in the device, and Oxygen concentration, etc., to harden the initial pattern.

In Example 8, the dew point (water concentration) and the oxygen concentration of the gas atmosphere were controlled by changing the gas atmosphere from N ₂ gas to pure dry gas (CDA).

In Example 9, in order to stop the supply of N ₂ gas to the gas atmosphere, after 3 hours, the operation of the step (2) was carried out to control the dew point (water concentration) of the gas atmosphere and the oxygen concentration.

(Comparative Example 9)

step 1):

Using the photoresist composition (1), the initial pattern of the line and the space was obtained in the same manner as in the examples 6 to 9 and the comparative examples 7 to 8.

Step (2):

Next, the initial pattern obtained by irradiation with light containing both ultraviolet rays and visible rays (without using a filter blocking wavelength) is used to harden the initial pattern, and a line width of 5.0 μm and pitch is obtained on the wafer surface. A 10 μm wide line and space photoresist pattern.

The curing conditions of the light irradiation are as follows.

Device: Ultraviolet irradiation device (manufactured by Tokyo Ohka Kogyo Co., Ltd.).

Irradiation wavelength: 254 nm, low pressure mercury lamp.

Irradiation amount: 150 mJ/cm ² .

Heating temperature of the substrate machine: adjusted to 80 °C.

Gas atmosphere inside the device: vacuum 1.5 Torr.

For the hardening conditions other than the above, for example, the temperature at which the initial pattern is hardened (the temperature of the initial pattern itself), the dew point (water concentration) of the gas atmosphere in the apparatus, and the oxygen concentration cannot be measured because they are located in the vacuum chamber. In 3, the content that cannot be measured is marked with "-".

Dissolution test for isoamyl acetate:

The tantalum wafer (evaluation sample) on which the resist pattern was formed in each of Examples 6 to 9 and Comparative Examples 7 to 9 was infiltrated with isoamyl acetate adjusted to 23 ° C for 10 seconds.

After infiltration, take out the evaluation sample and use a microscope (SEM, 100 Double) Observe the cross section of the wafer and confirm the state of the resist pattern cross section. The results are shown in Table 3.

The more soluble the photoresist pattern is, the lower the solubility to isoamyl acetate.

From the results shown in Table 3, it was found that the photoresist patterns obtained in Examples 6 to 9 confirmed that the entire pattern was sufficiently hardened.

On the other hand, in the resist patterns obtained in Comparative Examples 7 and 8, the hardening pattern was not sufficient, and the resist pattern obtained in Comparative Example 9 was hardened only by the surface layer portion of the pattern, and the internal hardening of the pattern was not full.

[Evaluation of heat resistance (2)] (Examples 10 to 34)

step 1):

Using the photoresist composition (1), the initial pattern of the line and space was obtained in the same manner as in the first embodiment.

Step (2):

Next, the initial pattern is irradiated with light containing both ultraviolet rays and visible rays (this is a light having a blocking wavelength of less than 300 nm and exceeding 450 nm), and the initial pattern is hardened.

The curing conditions of the light irradiation are as follows.

Device: Ultraviolet irradiation device (manufactured by Tokyo Ohka Kogyo Co., Ltd.).

Irradiation wavelength: 300~450nm, use a filter to block light in the metal halide light line with wavelengths below 300nm and over 450nm.

Irradiation amount: 180 mJ/cm ² .

Heating temperature of the substrate machine: adjusted to 100 °C.

Gas atmosphere in the device: The settings for supplying pure dry gas (CDA), dew point and oxygen concentration are shown in Table 4.

In Examples 10 to 34, according to the steps (1) and (2), a photoresist pattern of a line and a space having a line width of 1.5 μm and a pitch width of 3.0 μm was obtained.

Heat treatment after hardening:

The tantalum wafers formed by the photoresist patterns prepared in Examples 15 to 34 were placed on hot plates of 120 ° C, 130 ° C, 140 ° C, and 150 ° C, respectively. Heat for 5 minutes.

Subsequently, the state of the resist pattern after heat treatment (Examples 15 to 34) was compared with the unheated photoresist pattern (Examples 10 to 14), and the heat resistance was evaluated.

According to the evaluation results, the photoresist patterns obtained in Examples 15 to 18, 20 to 23, 25 to 28, and 30 to 33 did not appear on the surface of the pattern. The "wrinkle-like crack" and the deformation of the sidewall of the pattern (hot convection) were confirmed to have high heat resistance.

In the photoresist patterns obtained in Examples 19, 24, and 29 to 34, some of the micropattern sidewall deformations (hot convection) were found, and any of the photoresist patterns obtained in Examples 10 to 34 were presumed to be internal. All of them have been hardened, and they are also said to have high resistance to dry etching.

[Assessment of the influence of light source on the hardening of the initial pattern]

Using the photoresist composition (1), a photoresist pattern was formed in the following manner, and the influence of the light source was evaluated.

(Examples 35 to 59)

step 1):

Using the photoresist composition (1), the initial pattern of the line and space was obtained in the same manner as in the first embodiment.

Step (2):

Next, using the light source shown in Table 5, the initial pattern was irradiated with light to harden the initial pattern.

The curing conditions of the light irradiation are as follows.

Device: Ultraviolet irradiation device (manufactured by Tokyo Ohka Kogyo Co., Ltd.), LED lamp.

Irradiation wavelength: metal halide lamp-A (lamp-A) is 300-450 nm, metal halide lamp-B (lamp-B) is 300-450 nm, LED-A is 365 nm, LED-B is 385 nm and LED-C is 365 nm.

Irradiation amount: 180 mJ/cm ² .

Heating temperature of the substrate machine: adjusted to 100 °C.

Gas atmosphere in the device: supply N ₂ gas and pure dry gas (CDA), dew point -35 ° C, oxygen concentration 900 ppm mass basis.

In the examples 35 to 59, according to the steps (1) and (2), a photoresist pattern of a line and a space having a line width of 1.5 μm and a pitch of 3.0 μm was obtained.

The tantalum wafers on which the photoresist pattern was formed in each of Examples 40 to 59 were placed on hot plates of 120 ° C, 130 ° C, 140 ° C, and 150 ° C, and heated for 5 minutes.

Subsequently, the state of the photoresist pattern after heat treatment (Examples 40 to 59) was compared with the unheated photoresist pattern (Examples 35 to 39) to evaluate the influence of the light source.

As a result of the evaluation, it was found that the photoresist pattern obtained in Examples 40 to 54 did not reveal the "wrinkle crack" of the surface of the pattern and the deformation of the sidewall of the pattern (hot sag), and it was confirmed that the heat resistance was high. .

In the photoresist patterns obtained in Examples 55 to 59, it was found that the deformation of the micropattern sidewalls (hot convection), and any of the photoresist patterns obtained in Examples 35 to 59 were hardened to the inside thereof. Therefore, it can be said to have high resistance to dry etching.

In this way, it is confirmed that even if the LED is used for light irradiation, the resulting photoresist The pattern, the whole of the pattern can still be fully hardened.

[Evaluation of temperature conditions at the time of initial pattern hardening] (Examples 60 to 99, Comparative Examples 10 to 19)

The photoresist composition (2) is a naphthoquinone positive type resist (trade name: THMR-IP5700, manufactured by Tokyo Ohka Kogyo Co., Ltd.). The novolac naphthoquinone positive resist corresponds to the above photoresist composition (r1).

step 1):

The photoresist composition (2) was applied onto a 6-inch wafer subjected to hexamethyldioxane (HMDS) treatment using a spin coater, and subjected to a 90 ° C, 90 second preheating on a hot plate. After baking and drying, a photoresist film having a film thickness of 2.0 μm was formed.

Next, exposure was performed using a specific mask pattern using an exposure apparatus (trade name G7E, manufactured by Nikon Corporation; NA0.54). Next, heat treatment was performed after exposure at 110 ° C for 90 seconds.

Then, alkali development was carried out for 65 seconds using a 2.38 mass% aqueous solution of tetramethylammonium hydroxide "NMD-3" (trade name, manufactured by Tokyo Ohka Kogyo Co., Ltd.) at a temperature of 23 °C. As a result, an initial pattern of lines and spaces is formed.

Step (2):

Next, the initial pattern is irradiated with light containing both ultraviolet rays and visible rays (this is a light having a blocking wavelength of less than 300 nm and exceeding 450 nm), and the initial pattern is hardened.

The curing conditions of the light irradiation are as follows.

Device: Ultraviolet irradiation device (manufactured by Tokyo Ohka Kogyo Co., Ltd.).

Irradiation wavelength: 300~450nm, use a filter to block light in the metal halide light line with wavelengths below 300nm and over 450nm.

Irradiation amount: 180 mJ/cm ² .

The heating temperature of the substrate machine is set as shown in Tables 6 and 7, respectively.

Gas atmosphere in the device: supply N ₂ gas, dew point -37.3 ° C, oxygen concentration 770 ppm mass basis.

In the examples 60 to 99 and the comparative examples 10 to 19, according to the step (1) and the step (2), a line and space photoresist pattern having a line width of 2.0 μm and a pitch width of 4.0 μm were respectively obtained, and the line width was wide. A photoresist pattern of 5.0 μm and 10.0 μm wide pitch and space.

Heat treatment after hardening:

The tantalum wafers formed by the resist patterns are prepared in Examples 60 to 99 and Comparative Examples 10 to 19, respectively, at temperatures of 23 ° C (room temperature), 120 ° C, 130 ° C, 140 ° C, and 150 ° C. Leave under conditions for 5 minutes.

Subsequently, in this photoresist pattern, the angle of the angle (taper angle) formed by the surface of the germanium wafer and the sidewall of the pattern is obtained. The results are summarized in Tables 6 and 7.

The closer the cone angle is to 90°, the closer the photoresist pattern is to hardening.

From the results shown in Tables 6 and 7, it is found that when the temperature condition at the initial pattern hardening is set to 60 to 120 ° C, the heat resistance of the photoresist pattern can be improved; particularly preferably, when the temperature is set to 100 to 120 ° C, The heat resistance of the photoresist pattern can be increased upwards. In addition, it is known that the shape of the photoresist pattern can be controlled in accordance with the intended purpose.

[Evaluation of the amount of light exposure at the time of hardening the initial pattern] (Examples 100 to 129, Comparative Examples 20 to 29)

step 1):

Using the photoresist composition (2), the initial pattern of the line and space was obtained in the same manner as in Example 60.

Step (2):

Next, the initial pattern is irradiated with light containing both ultraviolet rays and visible rays (this is a light having a blocking wavelength of less than 300 nm and exceeding 450 nm), and the initial pattern is hardened.

The curing conditions of the light irradiation are as follows.

Device: Ultraviolet irradiation device (manufactured by Tokyo Ohka Kogyo Co., Ltd.).

Irradiation wavelength: 300~450nm, use a filter to block light in the metal halide light line with wavelengths below 300nm and over 450nm.

Irradiation: Set as shown in Tables 8 and 9.

Heating temperature of the substrate machine: adjusted to 120 °C.

Gas atmosphere in the device: supply N ₂ gas, dew point -37.3 ° C, oxygen concentration 770 ppm mass basis.

In the examples 100 to 129 and the comparative examples 20 to 29, according to the steps (1) and (2), the line and space photoresist patterns having a line width of 2.0 μm and a pitch width of 4.0 μm were respectively obtained, and the line width was 5.0. A photoresist pattern of line and space with μm and a width of 10.0 μm.

Heat treatment after hardening:

The examples 100 to 129 and the comparative examples 20 to 29 were respectively formed to have The photoresist pattern of the germanium wafer was placed at 23 ° C (room temperature), 120 ° C, 130 ° C, 140 ° C, 150 ° C for 5 minutes.

Then, in this photoresist pattern, the angle of the angle formed by the surface of the germanium wafer and the sidewall of the pattern (taper angle) is obtained. The results are summarized in Tables 8 and 9.

The closer the cone angle is to 90°, the closer the photoresist pattern is to hardening.

As a result of the results shown in Tables 8 and 9, it was found that the larger the amount of light irradiation at the time of initial pattern hardening, the smaller the variation of the taper angle, that is, the heat resistance of the resist pattern can be improved.

The above is a preferred embodiment of the present invention, but the present invention is not limited by the embodiments. The addition, omission, substitution, and other changes of any constituent elements are possible without departing from the spirit and scope of the invention. The present invention is not limited by the foregoing description, but is only limited by the scope of the appended claims.

Claims (3)

A method for forming a photoresist pattern, comprising the steps of: patterning a photoresist film formed on a support using a photoresist composition, and developing a pattern to form an initial pattern; And a method for forming a photoresist pattern in the step (2) of curing the initial pattern by using one or both of ultraviolet rays and visible rays, wherein the step (2) includes using The operation of irradiating the initial pattern is performed by blocking light of ultraviolet light and visible light that does not reach a wavelength of 300 nm. The method for forming a photoresist pattern according to claim 1, wherein in the step (2), the temperature condition at which the initial pattern is hardened is 120 ° C or lower. The method for forming a photoresist pattern according to claim 1 or 2, wherein the hardening of the initial pattern in the step (2) is carried out in a gas atmosphere having a dew point of -50 to -5 °C.