JP5465392B2 - Photoresist liquid and etching method using the same - Google Patents

Description

  The present invention relates to a photoresist compound and a photoresist solution capable of forming a fine pattern. Furthermore, this invention relates to the etching method of the to-be-processed surface using the said photoresist liquid.

In the manufacturing process of electronic parts such as semiconductor elements, magnetic bubble memories, and integrated circuits, a technique of forming a fine pattern and using this as an etching mask to etch the underlying surface is widely used.
In recent years, light-emitting elements such as LEDs have been utilized for various applications. This LED is a semiconductor element in which a semiconductor multilayer film including a light emitting layer is laminated on a substrate (hereinafter also referred to as “chip”), which is packaged with a resin or the like. Since the refractive index of the upper layer (or outermost layer) is different from that of the resin of the package, reflection occurs at the interface between the two and the luminous efficiency is lowered. Therefore, in order to prevent such reflection at the interface and improve the light emission efficiency, it has been proposed to provide a fine concavo-convex structure on the surface of the light extraction port of the chip (for example, Patent Document 1 and 2).
JP 2003-174191 A JP 2003-209283 A

In Patent Document 1, in the fifth embodiment, an antireflection film is provided as the uppermost layer constituting the light extraction port of the light emitting diode, and a fine uneven shape is formed on the surface of the antireflection film in advance. As a method of manufacturing a mold having a fine concavo-convex shape, press-molding the surface of the antireflection film with this mold, and forming a concavo-convex shape on the surface of the light extraction port, or a modification thereof, A method of roughening the surface of the antireflection film in a random direction with a grinder instead of press molding using a mold is disclosed. However, the former method requires a cumbersome process of creating a mold and has the disadvantage of costly mold production. The latter method is difficult to always make a uniform rough surface, There was a problem that the product had performance variations.
On the other hand, in Patent Document 2, a line-and-space pattern having a triangular cross section is formed on the current diffusion layer constituting the uppermost layer of the light extraction port of the semiconductor element by blade processing, and the hydrochloric acid treatment at a high temperature is performed to treat the current diffusion layer. A method of forming submicron irregularities on the surface and a line and space pattern using a photoresist on the current diffusion layer, and further applying the minute irregularities similar to the above to the current by reactive ion etching (RIE) A method of forming on the surface of the diffusion layer is disclosed. However, these methods also have a problem that a complicated process is required.

  Conventionally, photolithography is known as a technique used for manufacturing a fine concavo-convex structure and a semiconductor device. In photolithography, a resist composition containing a photosensitive compound is applied to the surface of a substrate or the like, then pattern exposure is performed through a photomask, and then development is performed to selectively select either an exposed portion or a non-exposed portion. Then, a resist pattern is formed. Thereafter, by using this resist pattern as an etching mask, a fine uneven pattern or a semiconductor element can be formed on the surface of a substrate or the like.

  However, in photolithography using a photoresist solution containing a conventional photosensitive compound, a step of developing after pattern exposure is essential, and the number of steps increases accordingly.

Accordingly, an object of the present invention is to provide a novel photoresist compound used for fine processing utilizing photolithography, more specifically, a novel photoresist capable of omitting a development process after pattern exposure. It is to provide a compound for use.
Another object of the present invention is to provide a photoresist solution using the above-mentioned photoresist compound.
Still another object of the present invention is to provide an etching method for etching a desired surface using the above-described photoresist solution.

  As a result of intensive studies to achieve the above object, the inventors of the present invention, when pattern exposure is performed on a dye film containing a cyanine dye and / or a styryl dye, causes chemical and / or chemical irradiation on the light irradiation portion due to heat generation of the dye. The physical property change occurred, and it was found that the dye film after the pattern exposure can be used as an etching mask, and the present invention has been completed.

That is, the above object has been achieved by the following means.
[1] A photoresist solution containing 100% by mass of a compound for photoresist, which is a compound selected from the group consisting of a cyanine dye and a styryl dye, based on the total solid content.
[2] The photoresist compound includes a nitrogen-containing heterocycle selected from the group consisting of optionally substituted benzoxazole, benzothiazole, indolenine, and those further condensed. 1].
[3] The photoresist compound according to [1] or [2], wherein the photoresist compound is a cyanine dye represented by the following general formula (I).
[In the general formula (I), Z ¹ and Z ² each represents a group of nonmetallic atoms necessary for forming a 5-membered or 6-membered nitrogen-containing heterocycle, which may be independently condensed, and L ¹ , L ² and L ³ each independently represent a methine chain, m represents an integer in the range of 0 to 2, R ¹ and R ² each independently represent a substituent, and m represents 2 A plurality of L ² and L ³ may be the same or different. p and q each independently represent 0 or 1, and R ¹¹ , R ¹² , R ¹³ and R ¹⁴ each independently represent a hydrogen atom or a substituent. X ¹ represents a counter ion that neutralizes the charge of the compound represented by formula (I). ]
[4] The photoresist compound according to [1] or [2], wherein the photoresist compound is a styryl dye represented by the following general formula (II).
[In the general formula (II), Z ³ represents a group of nonmetallic atoms necessary for forming a 5- or 6-membered nitrogen-containing heterocycle which may be condensed, and L ⁴ and L ⁵ are Independently represents a methine chain, R ³ , R ⁴ , R ⁵ and R ⁶ each independently represent a substituent, n represents an integer in the range of 0 to 4, and when n is 2 or more, a plurality thereof is present. R ⁶ may be the same or different. r represents 0 or 1, and R ¹⁵ and R ¹⁶ each independently represents a hydrogen atom or a substituent. X ² represents a counter ion that neutralizes the charge of the compound represented by formula (II). ]
[5] The photoresist compound according to any one of [1] to [4], wherein the photoresist compound has a thermal decomposition temperature of 100 ° C. or higher and 600 ° C. or lower.
[6] Forming a photoresist film by applying the photoresist liquid according to any one of [1] to [5] to a surface to be processed;
Pattern exposure to the photoresist film; and
Etching at least a part of the processing surface having the photoresist film after the pattern exposure, and etching at least a part of the processing surface in a region corresponding to the part exposed in the pattern exposure. Process surface etching method.
[7] The light used for the pattern exposure is a laser beam having a wavelength of λ nm, and the maximum absorption wavelength λmax of the photoresist compound contained in the photoresist film is in the range of λ ± 150 nm. ] The etching method of the to-be-processed surface of description.

  According to the present invention, it is possible to form an etching mask only by pattern exposure, in other words, without going through a developing step with a developer, so that a photo that is performed multiple times in the process of manufacturing various semiconductor devices. Each development process of the lithography process can be eliminated, and thereby a great simplification can be achieved. Furthermore, according to the present invention, fine irregularities can be formed on the surface to be processed.

[Photoresist compound]
The photoresist compound of the present invention is a compound selected from the group consisting of a cyanine dye and a styryl dye.
The inventors of the present invention have proposed that a dye film containing a compound selected from the group consisting of a cyanine dye and a styryl dye (hereinafter also referred to as “dye compound”) is partially irradiated with light, so that the light irradiated portion is localized. The present inventors have found that the physical properties are changed and the etching resistance is lower than that of the dye film before the light irradiation, and that the dye film can function as an etching mask. The present inventors estimate this phenomenon as follows.
When the dye film containing the dye compound is irradiated with light, for example, with a laser beam in a spot shape, the dye compound generates heat in the light irradiated portion. As a result of this heat generation, the dye compound undergoes changes in physical properties such as thermal decomposition. As a result, the light irradiation part of the dye film locally changes physically and / or chemically, and the durability decreases locally. A part (low durability part) is considered to be formed. The dye film in which the pits are formed functions not only as an etching mask, but also because the low durability part is etched more easily in the etching process, the dye film having the low durability part formed by pattern exposure. Can also function as an etching mask. It has also been found that the dye film containing the dye compound itself has excellent etching resistance and can function well as a durable film against etching. Here, the etching method may be dry etching or wet etching. In particular, the present invention is preferably applied to dry etching because a wet etching solution cleaning step is unnecessary.
In particular, when the present inventors observed the behavior of the dye film containing the above-mentioned dye compound during irradiation with laser light, the phenomenon that the temperature in the peripheral part of the laser beam was increased in the peripheral part as the temperature increased in the central part. confirmed. The reason for the temperature drop in this peripheral part is not clear, but due to the temperature drop in this peripheral part, pit formation and low durability part formation due to thermal decomposition occur in the central part of the laser light irradiation part, but physical property changes to the peripheral part Therefore, it is considered that a pattern having a diameter smaller than the beam diameter of the laser beam can be formed on the dye film by pattern exposure with laser light. Therefore, by pattern exposure to the dye film with laser light, only the exposure area with a small diameter that is much narrower than the area irradiated with the laser beam diameter becomes a low durability part, resulting in a beam that is narrower than the beam diameter of the laser light. Fine pattern exposure similar to the case of pattern exposure can be achieved.
Further, the dye film containing the above-described dye compound forms a pit or a low durability portion in the irradiated portion by pattern exposure, so that development processing after the pattern exposure is unnecessary, and an etching process is performed after the pattern exposure. be able to.
The “photoresist” in the present invention includes an embodiment in which a resist pattern is formed by heat generated by such pattern exposure.
Hereinafter, the photoresist compound of the present invention will be described in more detail.

  The photoresist compound of the present invention is a compound selected from the group consisting of a cyanine dye and a styryl dye. In the present invention, “cyanine dye” means that the alternating conjugated system constituting the chromophore is terminated by a hetero atom having a positive charge, whereby the positive charge is delocalized throughout the conjugated system. Means methine pigment. The “styryl dye” is a dye having a structure in which a hetero atom having a positive charge and a carbocyclic aromatic ring are bonded by a dimethine chain or a polymethine chain.

  Among the compounds selected from the group consisting of cyanine dyes and styryl dyes, preferred as the photoresist compound of the present invention are cyanine dyes represented by the following general formula (I) from the viewpoint of light absorption characteristics, thermal decomposition characteristics, etc. And styryl dyes represented by the following general formula (II).

[In the general formula (I), Z ¹ and Z ² each represents a group of nonmetallic atoms necessary for forming a 5-membered or 6-membered nitrogen-containing heterocycle, which may be independently condensed, and L ¹ , L ² and L ³ each independently represent a methine chain, m represents an integer in the range of 0 to 2, R ¹ and R ² each independently represent a substituent, and m represents 2 A plurality of L ² and L ³ may be the same or different. p and q each independently represent 0 or 1, and R ¹¹ , R ¹² , R ¹³ and R ¹⁴ each independently represent a hydrogen atom or a substituent. X ¹ represents a counter ion that neutralizes the charge of the compound represented by formula (I). ]

[In the general formula (II), Z ³ represents a group of nonmetallic atoms necessary for forming a 5- or 6-membered nitrogen-containing heterocycle which may be condensed, and L ⁴ and L ⁵ are Independently represents a methine chain, R ³ , R ⁴ , R ⁵ and R ⁶ each independently represent a substituent, n represents an integer in the range of 0 to 4, and when n is 2 or more, a plurality thereof is present. R ⁶ may be the same or different. r represents 0 or 1, and R ¹⁵ and R ¹⁶ each independently represents a hydrogen atom or a substituent. X ² represents a counter ion that neutralizes the charge of the compound represented by formula (II). ]

  Hereinafter, the compounds represented by the general formulas (I) and (II) will be described.

Formula (I)
In the general formula (I), Z ¹ and Z ² each represents a group of non-metallic atoms necessary for forming a 5-membered or 6-membered nitrogen-containing heterocycle that may be independently condensed, and p and q represents 0 or 1 each independently. The nitrogen-containing heterocycle formed by Z ¹ and Z ² may be unsubstituted or may have a substituent. There is no restriction | limiting in particular in the said substituent, As the specific example, the example of the substituent represented by R < ¹ >, R < ² > mentioned later can be mentioned.

  Specific examples of the nitrogen-containing heterocycle include, when p or q is 0, benzothiazole, benzoxazole, benzimidazole, indolenine, thiazole, thiazoline, oxazole, oxazoline, imidazole, imidazoline, 2-pyridinium, 2- Quinolinium and those fused with them are listed. When p or q is 1, 4-pyridinium, 4-quinolinium, and those fused with them are listed. Preferred are benzothiazole, benzoxazole, benzimidazole and indolenine, more preferred are benzoxazole and indolenine, and most preferred is indolenine.

R ¹ and R ² each independently represent a substituent. Preferred examples of the substituent include the following.
A substituted or unsubstituted linear, branched or cyclic alkyl group having 1 to 18 carbon atoms (preferably 1 to 8 carbon atoms) (eg, methyl group, ethyl group, propyl group, isopropyl group, n-butyl) Group, isobutyl group, sec-butyl group, t-butyl group, cyclohexyl group, methoxyethyl group, ethoxycarbonylethyl group, cyanoethyl group, diethylaminoethyl group, hydroxyethyl group, chloroethyl group, acetoxyethyl group, trifluoromethyl group, etc. ); C2-C18 (preferably C2-C8) alkenyl group (e.g., vinyl group); C2-C18 (preferably C2-C8) alkynyl group (e.g., ethynyl group, etc.) A substituted or unsubstituted aryl group having 6 to 18 carbon atoms (preferably 6 to 10 carbon atoms) (eg, phenyl group, 4-methylphenol group, 4 A methoxyphenyl group, a 4-carboxyphenyl group, a 3,5-dicarboxyphenyl group, etc.); a substituted or unsubstituted aralkyl group having 7 to 18 carbon atoms (preferably 7 to 12 carbon atoms) (eg, benzyl group, carboxy group) A benzyl group or the like; a substituted or unsubstituted acyl group having 2 to 18 carbon atoms (preferably 2 to 8 carbon atoms) (eg, acetyl group, propionyl group, butanoyl group, chloroacetyl group, etc.); (Preferably having 1 to 8 carbon atoms) substituted or unsubstituted alkyl or arylsulfonyl group (eg, methanesulfonyl group, p-toluenesulfonyl group, etc.); having 1 to 18 carbon atoms (preferably having 1 to 8 carbon atoms) Alkylsulfinyl group (eg, methanesulfinyl group, ethanesulfinyl group, octanesulphinyl group, etc.); C 2-18 (preferably carbon 2-8) alkoxycarbonyl group (eg, methoxycarbonyl group, ethoxycarbonyl group, butoxycarbonyl group, etc.); aryloxycarbonyl group (eg, phenoxycarbonyl) having 7-18 carbon atoms (preferably 7-12 carbon atoms) Group, 4-methylphenoxycarbonyl group, 4-methoxyphenylcarbonyl group, etc.); a substituted or unsubstituted alkoxy group having 1 to 18 carbon atoms (preferably 1 to 8 carbon atoms) (eg, methoxy group, ethoxy group, n -Butoxy group, methoxyethoxy group, etc.); C6-C18 (preferably C6-C10) substituted or unsubstituted aryloxy group (eg, phenoxy group, 4-methoxyphenoxy group, etc.); C1 -18 (preferably 1-8 carbon atoms) alkylthio group (eg, methylthio group, ethylthio group, etc.); Preferably an arylthio group having 1 to 8 carbon atoms (eg, phenylthio group); a substituted or unsubstituted acyloxy group having 2 to 18 carbon atoms (preferably having 2 to 8 carbon atoms) (eg, an acetoxy group, ethylcarbonyloxy) Group, cyclohexylcarbonyloxy group, benzoyloxy group, chloroacetyloxy group, etc.); substituted or unsubstituted sulfonyloxy group having 1 to 18 carbon atoms (preferably 1 to 8 carbon atoms) (eg, methanesulfonyloxy group, etc.) A substituted or unsubstituted carbamoyloxy group having 2 to 18 carbon atoms (preferably 2 to 8 carbon atoms) (eg, methylcarbamoyloxy group, diethylcarbamoyloxy group, etc.); an unsubstituted amino group, or 1 to 1 carbon atoms; 18 (preferably having 1 to 8 carbon atoms) substituted amino group (eg, methylamino group, dimethylamino group, diethylamino group) Group, anilino group, methoxyphenylamino group, chlorophenylamino group, pyridylamino group, methoxycarbonylamino group, n-butoxycarbonylamino group, phenoxycarbonylamino group, phenylcarbamoylamino group, ethylthiocarbamoylamino group, methylsulfamoylamino group Group, phenylsulfamoylamino group, ethylcarbonylamino group, ethylthiocarbonylamino group, cyclohexylcarbonylamino group, benzoylamino group, chloroacetylamino group, methanesulfonylamino group, benzenesulfonylamino group, etc.); An amide group having 18 (preferably 1 to 8 carbon atoms) (eg, acetamido group, acetylmethylamide group, acetyloctylamide group, etc.); substitution of 1 to 18 carbon atoms (preferably 1 to 8 carbon atoms) Or an unsubstituted ureido group (eg, an unsubstituted ureido group, a methylureido group, an ethylureido group, a dimethylureido group, etc.); a substituted or unsubstituted group having 1 to 18 carbon atoms (preferably 1 to 8 carbon atoms) Carbamoyl group (eg, unsubstituted carbamoyl group, methylcarbamoyl group, ethylcarbamoyl group, n-butylcarbamoyl group, t-butylcarbamoyl group, dimethylcarbamoyl group, morpholinocarbamoyl group, pyrrolidinocarbamoyl group, etc.); unsubstituted sulfamoyl Group or a substituted sulfamoyl group having 1 to 18 carbon atoms (preferably 1 to 8 carbon atoms) (eg, methylsulfamoyl group, phenylsulfamoyl group, etc.); halogen atom (eg, fluorine atom, chlorine atom, bromine atom) Hydroxyl group; mercapto group; nitro group; cyano group; carboxyl group; sulfo group; A phosphono group (eg, diethoxyphosphono group, etc.); a heterocyclic group (eg, oxazole ring, benzoxazole ring, thiazole ring, benzothiazole ring, imidazole ring, benzimidazole ring, indolenine ring, pyridine ring, morpholine ring, Piperidine ring, pyrrolidine ring, sulfolane ring, furan ring, thiophene ring, pyrazole ring, pyrrole ring, chroman ring, and coumarin ring).

R ¹ and R ² are preferably an alkyl group having 1 to 18 carbon atoms, and most preferably a methyl group.

R ¹¹ , R ¹² , R ¹³ and R ¹⁴ each independently represents a hydrogen atom or a substituent. There is no particular limitation for a substituent when ^{R 11, R 12, R 13} , R 14 is a substituent. As an example of the said substituent, what was mentioned as an example of the substituent represented by R < ¹ >, R < ² > is mentioned.

In general formula (I), L ¹ , L ² and L ³ each independently represent a methine chain. The methine chain may have a substituent, and examples of the substituent include those exemplified as the substituents represented by R ¹ and R ² . It is preferable not to have a substituent.

m represents an integer in the range of 0-2. When m represents 2, a plurality of L ² and L ³ may be the same or different. m is preferably 0 or 1, and most preferably 0.

X ¹ represents a counter ion that neutralizes the charge of the compound represented by formula (I). Whether a dye is a cation, an anion, or has a net ionic charge depends on its auxiliary chromophore and substituent. When the substituents have dissociative group may have dissociated to negative charge, the charge of the whole molecule in this case is neutralized by X ^1. Typical cations are inorganic or organic ammonium ions (eg tetraalkylammonium ions, pyridinium ions) and alkali metal ions, while the anions can be either inorganic or organic anions, for example , Halogen anions (eg, fluoride ions, chloride ions, bromide ions, iodide ions), substituted aryl sulfonate ions (eg, p-toluene sulfonate ion, p-chlorobenzene sulfonate ion), aryl disulfonate ions (For example, 1,3-benzenedisulfonate ion, 1,5-naphthalenedisulfonate ion, 2,6-naphthalenedisulfonate ion), alkyl sulfate ion (for example, methyl sulfate ion), sulfate ion, thiocyanate ion, peroxygen Chlorate ion, Tiger tetrafluoroborate ion, picrate ion, acetate ion and trifluoromethanesulfonate ion.
Furthermore, an ionic polymer or another dye having a charge opposite to that of the dye may be used as the charge balance counter ion, or a metal complex ion (for example, bisbenzene-1,2-dithiolatonickel (III), azo dye chelate). Compound) is also possible

Formula (II)
In the general formula (II), Z ³ represents a nonmetallic atom group necessary for forming a 5-membered or 6-membered nitrogen-containing heterocycle which may be condensed. r represents 0 or 1, and details such as specific examples of the nitrogen-containing heterocycle formed with Z ³ are the same as those of the nitrogen-containing heterocycle formed with Z ¹ and Z ² in the general formula (I) It is. R ¹⁵ and R ¹⁶ each independently represents a hydrogen atom or a substituent. There is no particular limitation on the substituent when R ¹⁵ and R ¹⁶ are substituents, and the substituent when Z ³ has a substituent. As an example of the said substituent, what was mentioned as an example of the substituent represented by R < ¹ >, R < ² > is mentioned.

R ³ , R ⁴ , R ⁵ and R ⁶ each independently represent a substituent. Details of specific examples of R ^{3 to} R ⁶ are the same as those of R ¹ and R ² in the general formula (I).

n represents an integer in the range of 0-4. When n is 2 or more, a plurality of R ⁶ may be the same or different. n is preferably 0.

In general formula (II), L ⁴ and L ⁵ each independently represent a methine chain. The methine chain may have a substituent, and examples of the substituent include those exemplified as the substituents represented by R ¹ and R ² in the general formula (I). It is preferable not to have a substituent.

X ² represents a counter ion that neutralizes the charge of the compound represented by formula (II). Details of specific examples of X ² and the like are the same as those of X ¹ in the general formula (I).

  Specific examples of the cyanine dye and styryl dye as the photoresist compound of the present invention include a cyanine dye described in JP-A No. 2001-232945 and a styryl dye described in JP-A No. 2002-74740. . Examples of some of the compounds are shown below. A-1 to A-65 are specific examples of cyanine dyes, and B-1 to B-10 are specific examples of styryl dyes.

As the photoresist compound of the present invention, an optimum one can be selected according to the wavelength of light used for pattern exposure.
For example, with respect to the maximum absorption wavelength (λmax), as a general index, when the wavelength of the laser beam used is λnm, the photoresist film by pattern exposure is efficiently decomposed or modified, so that λ ± 150nm In the range of λ ± 100 nm, and more preferably in the range of λ ± 100 nm. For example, when a semiconductor laser beam having a wavelength of 650 nm is used, it can be selected from photoresist compounds having a maximum absorption wavelength in the range of 500 nm to 800 nm, more preferably in the range of 550 nm to 750 nm. Moreover, when using a semiconductor laser beam having a wavelength of 405 nm, it can be selected from photoresist compounds having a maximum absorption wavelength in the range of 255 nm to 555 nm, more preferably in the range of 305 nm to 505 nm.

  Furthermore, the thermal decomposition temperature of the photoresist compound of the present invention is preferably 100 ° C. or higher and 600 ° C. or lower, more preferably 120 ° C. or higher and 550 ° C. or lower, from the viewpoint of sensitivity during pattern exposure with a laser. Most preferably, the temperature is 150 ° C. or more and 500 ° C. or less.

The thermal decomposition temperature in the present invention refers to a value obtained by TG / DTA measurement. Specifically, for example, Seiko Instruments Inc. Using EXSTAR6000 manufactured, the temperature was increased at a rate of 10 ° C./min in the range of 30 ° C. to 550 ° C. under a N ₂ stream (flow rate 200 ml / min), and the thermal decomposition temperature was reached when the mass reduction rate reached 10%. Can be requested.

  The photoresist compound of the present invention can be synthesized by a known method, and some of them are commercially available.

[Photoresist solution]
The photoresist solution of the present invention contains the compound for photoresist of the present invention, and preferably contains a solvent. The photoresist liquid of the present invention may contain one type of the compound for photoresists of the present invention, or may contain two or more types. As the solvent, a good solvent for the photoresist compound of the present invention is preferably used. Furthermore, the photoresist solution of the present invention can optionally contain other components in addition to the above components. In order to form a resist film having excellent processability, the content of the photoresist compound in the photoresist solution of the present invention is 50% by mass or more based on the total solid content contained in the photoresist solution. It is preferably 70% by mass or more, more preferably 90% by mass or more. The upper limit is, for example, 100% by mass.

  A photoresist film can be formed by applying the photoresist solution of the present invention onto the surface to be treated and evaporating and removing the solvent. Examples of the coating method include a spray method, a spin coat method, a dip method, a roll coat method, a blade coat method, a doctor roll method, a doctor blade method, a curtain coat method, a slit coat method, and a screen printing method. The spin coating method is preferably used in terms of excellent productivity and easy control of the film thickness. As a method for removing the solvent from the applied photoresist solution, a conventionally known method can be used. For example, when applied by a spin coating method, the solvent can be evaporated by increasing the spin speed as it is. At that time, evaporation of the solvent may be promoted by spraying a gas from the nozzle onto the coating surface. Furthermore, as in the conventional photoresist coating process, so-called pre-baking may be performed in which the spin-coated photoresist liquid film is heated (baked). As a method for removing the solvent, a method in which a photoresist solution is applied by a spin coating method, and the solvent is removed by increasing the rotation speed of the spin as it is is particularly preferable. In this case, it is preferable to perform an annealing treatment for further heating. The annealing treatment has an effect of increasing the strength and stability as a photoresist film. The lower limit of the heating temperature is, for example, 55 ° C. or higher, preferably 65 ° C. or higher, more preferably 75 ° C. or higher. The upper limit of the heating temperature is, for example, 200 ° C. or lower, preferably 150 ° C. or lower, more preferably 100 ° C. or lower. is there. The lower limit of the time is, for example, 5 minutes or more, preferably 15 minutes or more, more preferably 30 minutes or more, and the upper limit is, for example, 4 hours or less, preferably 2 hours or less, more preferably 1 hour or less. By annealing under such conditions, the strength and stability of the photoresist film can be increased without reducing the productivity.

  The concentration of the total solid content in the photoresist solution of the present invention is such that the coating property (for example, the film thickness after coating and solvent removal is within a desired range, and the film thickness is uniform over the entire surface to be processed. In addition, even if there is some unevenness on the surface to be processed, the coating film having a uniform thickness is formed following the unevenness, etc. More preferably, it is 0.4 mass% or more and 5 mass% or less, More preferably, it is 0.7 mass% or more and 2 mass% or less.

The solvent that can be used in the photoresist solution of the present invention is preferably one having an appropriate volatility at the time of application in consideration of the application property by a spin coating method, and has the following physical properties in terms of production suitability. Is more preferable.
1. The boiling point is preferably 60 ° C or higher and 300 ° C or lower, more preferably 70 ° C or higher and 250 ° C or lower, and most preferably 80 ° C or higher and 200 ° C or lower.
2. The viscosity is preferably from 0.1 cP to 100 cP, more preferably from 0.5 cP to 50 cP, and most preferably from 1 cP to 10 cP.
3. The flash point is preferably 25 ° C. or higher, more preferably 30 ° C. or higher, and most preferably 35 ° C. or higher.

  Specific examples of the solvent include hydrocarbons (cyclohexane, 1,1-dimethylcyclohexane, etc.), alcohols (butanol, diacetone alcohol, tetrafluoropropanol, etc.), glycol ethers (methyl cellosolve, propylene glycol monomethyl). Ethers, propylene glycol monomethyl ether acetate, etc.) esters (butyl acetate, methyl lactate, ethyl lactate, etc.), ketones (methyl ethyl ketone, methyl isobutyl ketone, etc.), nitriles (propionitrile, benzonitrile, etc.), amides ( Dimethylformamide), sulfones (dimethyl sulfoxide, etc.) carboxylic acids (acetic acid, etc.), amines (triethylamine, etc.), halogens (trichloromethane, hydrofluorocar Emissions, etc.), aromatic Shokurui (toluene, xylene, etc.) and the like. Of these, alcohols or glycol ethers are particularly preferred because of their coating properties. The said solvent may be used independently and may mix and use 2 or more types.

Although the photoresist liquid of this invention should just contain the said pigment | dye compound as a solid content at least, you may contain another component as needed. However, the total amount of the other components is preferably not more than 1-fold by mass with respect to the dye compound.
Examples of other components include a binder, a fading inhibitor, an antioxidant, a UV absorber, a plasticizer, and a lubricant. Examples of binders include natural organic polymer materials such as gelatin, cellulose derivatives, dextran, rosin and rubber; hydrocarbon resins such as polyethylene, polypropylene, polystyrene and polyisobutylene; polyvinyl chloride, polyvinylidene chloride, polychlorinated Vinyl resins such as vinyl / polyvinyl acetate copolymers, acrylic resins such as polymethyl acrylate and polymethyl methacrylate, polyvinyl alcohol, chlorinated polyethylene, epoxy resins, butyral resins, rubber derivatives, phenol / formaldehyde resins, etc. Examples thereof include synthetic organic polymers such as an initial condensate of a thermosetting resin. When adding a binder to the photoresist solution of the present invention, the amount of the binder added is preferably 0.01 to 1 times the mass ratio of the photoresist compound of the present invention, More preferably, the amount is 0.1 to 0.5 times.

Since the photoresist compound of the present invention generally does not decompose or denature under normal indoor lighting environment, a safety light such as a conventional photoresist (for example, ultraviolet light or light having a shorter wavelength than that is cut off). It is not necessary to use under lighting. However, when used under illumination in such a normal indoor environment, various anti-fading agents can be contained in the photoresist solution in order to form a resist film having excellent light resistance.
As the antifading agent, a singlet oxygen quencher is generally used. As the singlet oxygen quencher, those described in publications such as known patent specifications can be used. Specific examples thereof include JP-A Nos. 58-175893, 59-81194, 60-18387, 60-19586, 60-19587, and 60-35054. 60-36190, 60-36191, 60-44554, 60-44555, 60-44389, 60-44390, 60-54892, JP-A-60-47069, JP-A-63-209995, JP-A-4-25492, JP-B-1-38680, JP-A-6-26028, etc., German Patent 350399, and Japan Examples include those described in Chemical Society Journal, October 1992, page 1141. The amount of the anti-fading agent such as the singlet oxygen quencher used can be, for example, in the range of 0.1 to 50% by mass with respect to the amount of the photoresist compound of the present invention, It can be in the range of 5-45% by mass, more preferably in the range of 3-40% by mass, particularly preferably in the range of 5-25% by mass.

  As will be described later, according to the photoresist solution of the present invention, an etching mask can be formed without going through a development process. Therefore, a combination component of o-naphthoquinone diazitosulfonic acid ester and novolak resin, which is included as an essential component in a normal photopolymer type resist solution requiring a development process, a combination component of a photoacid generator and an acid-decomposable compound, light The combination component of the base generator and the base decomposable compound, the combination component of the photo radical generator and the addition polysaturated unsaturated compound is not an essential component in the photoresist solution of the present invention, the photoresist solution of the present invention is It is preferable not to contain these components.

  The photoresist solution of the present invention can be obtained by mixing the photoresist compound of the present invention with the above-described components as necessary.

  A photoresist film can be formed by applying the photoresist solution of the present invention to the surface to be processed and removing the solvent, and exposing the photoresist film with a laser beam in a desired pattern. A resist having a desired pattern can be formed. The details of the coating method of the photoresist liquid for forming the resist film are as described above.

  Since the photoresist film of the present invention bears its function, the photoresist film preferably contains the photoresist compound in an amount of 50% by mass or more based on the total mass of the photoresist film. The content is more preferably 70% by mass or more, and still more preferably 90% by mass or more. The upper limit is, for example, 100% by mass. The various components that can be contained in the photoresist film are as described above for the photoresist composition of the present invention.

  In the photoresist solution of the present invention, the aspect in which the total amount of the solid content is composed of the photoresist compound is an excess photoresist solution after the surface to be processed is provided in the spin coating process (for example, during spin coating). This is particularly preferable in that it is easy to collect and reuse the photoresist solution shaken off from the surface to be processed.

  The photoresist liquid of the present invention can be applied to any application as long as it requires a fine processing. For example, in various processes such as a manufacturing process of a semiconductor device such as an LSI, LED, CCD, or solar cell, a manufacturing process of an FPD such as a liquid crystal, a PDP, or an EL, or a manufacturing process of an optical member such as a lens or a film. It can be used instead of the resist solution. That is, instead of the conventional photoresist solution coating and solvent removal step, pattern exposure step and development step, the photoresist solution coating and solvent removal step and pattern exposure step of the present invention can be used.

  The photoresist liquid of the present invention can also be used in the production of a master for nanoimprinting.

  Furthermore, the photoresist solution of the present invention is used to improve the light extraction efficiency of LEDs by forming fine irregularities on the surface, back surface (for example, sapphire substrate), side surfaces, etc. of LED chips. can do. In general, the material constituting the outermost layer (for example, a current diffusion layer or a transparent electrode) serving as a light extraction port of an LED chip has a refractive index different from that of the resin for the package. While the refractive index is 3 or more, the refractive index of the latter package resin is around 1.5. When light is extracted from such a high refractive index portion to a low refractive index portion, the light is reflected at the interface and the light extraction efficiency is reduced. By doing so, the light extraction efficiency can be improved. Therefore, after forming a layer (for example, a current diffusion layer) that becomes a light extraction port of the LED chip, the photoresist liquid of the present invention is applied to the surface of this layer, and the solvent is removed to form a photoresist film. Then, this photoresist film is subjected to pattern exposure in which only a portion corresponding to a concave portion of a desired fine concavo-convex pattern is irradiated with laser light, followed by etching, and the surface of the extraction port corresponding to the portion irradiated with the above laser light By etching the film to form a concave portion, fine irregularities can be formed at the outlet. Thereafter, the LED chip can be completed through a necessary process (for example, a process of forming an electrode on the surface of the current diffusion layer). The light extraction port of the LED chip thus obtained has fine irregularities on the surface. Since this LED element is packaged into an LED, fine irregularities are formed at the interface between the packaging resin and the light extraction port, so that an LED with less reflection at the interface and high light extraction efficiency is produced. be able to. Thus, when taking out from a portion with a large refractive index to a portion with a small refractive index, the light extraction efficiency can be increased by providing fine irregularities at the interface. The depth h and the diameter d of the concave portion to be formed at the light emitting portion interface may be any size that causes scattering / diffraction of light generated in the light emitting portion, and preferably not less than a quarter of the emission wavelength. It can be designed based on scattering theory.

As described above, when forming fine irregularities on the surface to be processed, a photoresist film is formed on the surface using the photoresist solution of the present invention, and a fine pattern is exposed by laser, and this is used as a mask. Then, fine unevenness corresponding to the fine pattern can be formed on the surface to be processed by RIE or the like. In addition, a mask layer is provided on the surface to be processed, a photoresist film is formed thereon using the photoresist solution of the present invention, this is finely processed by laser, and then fine holes are formed in the mask layer by RIE. Furthermore, it is also possible to etch the surface to be processed deeper with ICP (inductively coupled plasma) through the mask layer in which the fine holes are formed. The etching method using such a mask layer is an advantageous method when the surface to be processed is hard and difficult to be etched like sapphire. The mask layer is preferably an inorganic oxide film or nitride film such as SiO ₂ , TiO ₂ , SiN, or SiON.

  Further, the thickness t of the photoresist film formed using the photoresist solution of the present invention and the diameter d of the recesses are determined by etching of the type of the photoresist compound of the present invention, the material of the surface to be processed, the selection ratio, etc. It can be set according to the process conditions. The optical characteristics during laser recording should also be set in consideration. As a preferred range, the upper limit of the thickness t of the resist layer is a value satisfying t <100d, more preferably a value satisfying t <10d, and the lower limit is preferably a value satisfying t> d / 100, A value satisfying t> d / 10 is more preferable.

[Surface etching method]
Furthermore, the present invention relates to a method for etching a surface to be processed. The etching method of the present invention comprises applying the photoresist solution of the present invention to a surface to be processed to form a photoresist film, pattern exposing the photoresist film, and applying the photoresist film after the pattern exposure Etching at least a part of the processed surface, and etching at least a part of the processed surface in a region corresponding to the exposed part in the pattern exposure.

  In the photoresist film subjected to pattern exposure, pits are formed in the exposed photoresist film at the time of pattern exposure, or a part having a local change in physical properties such as a low durability part is formed. In the etching process, the processing surface corresponding to the pits and / or the low durability portion of the photoresist film is preferentially etched, and the processing surface underneath is also etched to form a recess. In this way, at least a part of the surface to be processed in the region corresponding to the exposed portion in the pattern exposure can be etched to form fine irregularities on the surface to be processed. Further, when the surface to be processed has a plurality of thin layers, at least one of the thin layers can be removed in a pattern. By utilizing this, various semiconductor devices can be manufactured.

  For pattern exposure, a method in which exposure is performed through a photomask using a known stepper can also be adopted. However, the laser beam is pulse-modulated, and the modulated laser beam is narrowed down through a lens. Pattern exposure is preferably performed so that the focal point is a photoresist film. As a pattern exposure apparatus for performing such light irradiation, a recording apparatus used for recording information on an optical disk is suitable. However, monochromatic light such as laser light may not be used as long as the light can be condensed to a required size.

  The type of laser light may be any laser such as a gas laser, a solid laser, or a semiconductor laser. However, in order to simplify the optical system, it is preferable to employ a solid laser or a semiconductor laser. The laser light may be continuous light or pulsed light, but it is preferable to employ laser light whose emission interval can be freely changed. An example of such a laser is a semiconductor laser. In addition, when the laser cannot be directly on-off modulated, it is preferable to modulate by an external modulation element.

  A higher laser power is preferable for increasing the processing speed. However, as the laser power is increased, the scanning speed (speed for scanning the coating film with laser light; for example, the rotational speed of the optical disk drive described later) must be increased. Therefore, the upper limit value of the laser power is preferably 100 W in consideration of the upper limit value of the scanning speed, more preferably 10 W, still more preferably 5 W, and most preferably 1 W. The lower limit of the laser power is preferably 0.1 mW, more preferably 0.5 mW, and even more preferably 1 mW.

  Further, the laser light is preferably light that has excellent transmission wavelength width and coherency and can be narrowed down to a spot size equivalent to the wavelength. In addition, it is preferable to adopt a strategy generally used in an optical disc as the light pulse irradiation condition. That is, it is preferable to adopt conditions such as recording speed, the peak value of the laser beam to be irradiated, and the pulse width as used in an optical disc.

  The wavelength of the laser light may be any wavelength that can provide a large laser power. For example, 1064 ± 30 nm, 800 ± 50 nm, 670 ± 30 nm, 532 ± 30 nm, and 405 nm are easily obtained laser wavelengths. ± 50 nm, 266 ± 30 nm, and 200 ± 30 nm are preferable. Among these, 780 ± 30 nm, 660 ± 20 nm, or 405 ± 20 nm, which can provide a large output with a semiconductor laser, is preferable. Most preferably, it is 405 ± 10 nm. The maximum absorption wavelength λa of the photoresist compound to be used and the wavelength λw of the laser beam may be either λa ≦ λw or λa ≧ λw. In order to uniformly apply light from the front surface to the back surface of the photoresist film in the thickness direction and to heat the entire surface to form a clean hole, it is preferable that the amount of absorption of the thin film is within a certain range. If there is too much absorption, light will reach only the surface, and if it is too little, light will not turn into heat and efficiency will deteriorate. The upper limit of the extinction coefficient k representing the ease of absorption of the material is suitably 2 or less, preferably 1 or less, particularly preferably 0.5 or less. The lower limit is preferably 0.0005 or more, 0.005 or more, or 0.05 or more. If it is the said relationship, the light absorption amount of the compound for photoresists is appropriate, and a favorable pit or a low durability part can be formed by pattern exposure.

  The thickness of the resist film can be appropriately set within a range of 1 to 10,000 nm, for example. The lower limit of the thickness is preferably 10 nm or more, and more preferably 30 nm or more. The reason is that if the thickness is too thin, it is difficult to obtain an etching effect. Moreover, the upper limit of thickness becomes like this. Preferably it is 1000 nm or less, More preferably, it is 500 nm or less. The reason is that if the thickness is too thick, a large laser power is required, and it becomes difficult to form a deep hole, and further, the processing speed decreases.

  As the light irradiation method, for example, a well-known pit formation method for a write-once optical disc or a write-once optical disc can be applied. Specifically, for example, by detecting the intensity of the reflected light of the laser that changes depending on the pit size and correcting the laser output so that the intensity of the reflected light is constant, a uniform pit is formed. A known running OPC technique (for example, see Japanese Patent No. 3096239) can be applied. In addition, since the resist film of the present invention can function as an etching mask by removing the portion at the time of etching if there is a portion where the physical property has changed to such an extent that it is removed by etching by light irradiation, It is not essential that pits (openings) that can be recognized visually are formed. Also, the size and processing pitch of the pits and physical property changing portions can be controlled by adjusting the optical system. Since the laser light has the highest light intensity near the center and gradually decreases toward the outside, fine pits having a diameter smaller than the spot diameter of the laser light can be formed on the coating film. Further, when it is desired to form a pit larger than the minimum processing shape of the laser beam, a laser spot may be connected.

Below, the specific aspect of the optical system used for a process is demonstrated. However, this invention is not limited to the aspect shown below.
As the light irradiation device, one having the same configuration as a general optical disk drive can be used. As the optical disk drive, for example, one having a configuration described in Japanese Patent Laid-Open No. 2003-203348 can be used. Using such an optical disk drive, if the object to be processed on which the coating film is formed has a disk shape, if the shape is different, it is loaded on the disk drive by pasting it on a dummy optical disk. And a laser beam is irradiated on a coating film with a suitable output. Furthermore, a pulse signal or a continuous signal may be input to the laser light source so that this irradiation pattern matches the processing pattern. Further, by using a focusing technique similar to that of the optical disk drive, for example, an astigmatism method, even if the coating film surface is wavy or warped, it can be easily condensed on the coating film surface. Further, as in the case of recording information on the optical recording disc, the entire coating film can be irradiated with light periodically by moving the optical system in the radial direction while rotating the workpiece.

  As for the light irradiation conditions, for example, the lower limit of the numerical aperture NA of the optical system is preferably 0.4 or more, more preferably 0.5 or more, and still more preferably 0.6 or more. Moreover, it is preferable that the upper limit of numerical aperture NA is 2 or less, More preferably, it is 1 or less, More preferably, it is 0.9 or less. When the numerical aperture is increased, the so-called liquid immersion method in which a liquid is interposed between the objective lens and the photoresist film is advantageous in that the focus adjustment is facilitated. This is because if the numerical aperture NA is too small, fine processing cannot be performed, and if it is too large, the margin for the angle during light irradiation is reduced. The wavelengths of the optical system are, for example, 405 ± 30 nm, 532 ± 30 nm, 650 ± 30 nm, and 780 ± 30 nm. This is because these wavelengths are easy to obtain a large output. A shorter wavelength is preferable because fine processing can be performed.

  The lower limit of the output of the optical system is, for example, 0.1 mW or more, preferably 1 mW or more, more preferably 5 mW or more, and further preferably 20 mW or more. The upper limit of the output of the optical system is, for example, 1000 mW or less, preferably 500 mW or less, more preferably 200 mW or less. This is because if the output is too low, processing takes time, and if it is too high, the durability of the members constituting the optical system becomes low.

  The lower limit of the linear velocity for moving the optical system relative to the coating film surface is, for example, 0.1 m / s or more, preferably 1 m / s or more, more preferably 5 m / s or more, and still more preferably 20 m / s. That's it. The upper limit of the linear velocity is, for example, 500 m / s or less, preferably 200 m / s or less, more preferably 100 m / s or less, and still more preferably 50 m / s or less. If the line speed is too high, it is difficult to increase the processing accuracy, and if it is too slow, it takes time for processing and it is difficult to process into a good shape. As an example of a specific optical processing machine including an optical system, NE0500 manufactured by Pulstec Industrial Co., Ltd. can be used, for example.

  The photoresist film described above can be used as an etching mask without undergoing a development process after pattern exposure. In addition, you may insert the post-baking which performs heat processing as a process after the pattern exposure and before the etching demonstrated below. By performing post-baking, the photoresist film after pattern exposure can be firmly fixed to the surface to be processed, and the function as a mask for subsequent etching can be improved. The lower limit of the post-baking heating temperature is, for example, 55 ° C. or more, preferably 65 ° C. or more, more preferably 75 ° C. or more. The upper temperature limit is, for example, 200 ° C. or less, preferably 150 ° C. or less, more preferably 100 ° C. It is as follows. By performing the heat treatment in such a range, the above-described effect can be obtained without causing a decrease in productivity.

Examples of the etching method include various etching methods such as wet etching and dry etching, and a method corresponding to the physical properties of the surface to be etched may be employed. In order to perform microfabrication, it is preferable to employ RIE (reactive ion etching) in which the etching gas has high straightness and enables fine patterning. In RIE, an object to be processed is placed in an airtight processing chamber, and after a predetermined processing gas is introduced and evacuated to a predetermined reduced pressure atmosphere, for example, a predetermined pressure is applied to an electrode formed in the processing chamber. Plasma is excited by applying high frequency power, and an object to be processed is etched by etchant ions in the plasma. This RIE etching gas can be selected according to the material to be etched.
The photoresist film formed from the photoresist liquid of the present invention is usually removed after etching, but may be left without being removed depending on the application. The removal of the photoresist film can be performed, for example, by a wet removal method using a stripping solution (for example, ethanol).

Although the embodiment in which the photoresist solution of the present invention is used for etching has been described above, the photoresist solution of the present invention can also be used for depositing a desired substance in a desired region on the surface to be processed.
For example, the LED chip is provided with an electrode such as AuZn or AuGe on a part of the surface of the light extraction port (for example, current diffusion layer). In this case, the photoresist liquid of the present invention is applied to the surface of the light extraction port (for example, the surface of the current diffusion layer), the solvent is removed to form a photoresist film, and then laser light is applied to the region where the electrode is to be formed. Irradiate to remove the photoresist film. In this case, the amount of laser light applied to the photoresist film may be sufficient to form a low durability portion on the photoresist film. In that case, the photoresist of the low durability portion is subsequently etched. By removing the film, the photoresist film in the region where the electrode is to be formed can be removed. Thereafter, a material to be an electrode (for example, AuZn or AuGe) is deposited under vacuum, and then the photoresist film is removed, whereby an electrode is formed in a desired region on the surface of the light extraction port.

  As described above, the photoresist compound of the present invention can be used for forming fine irregularities and for producing semiconductor devices. Specific examples include, but are not limited to, various electronic components such as semiconductor elements, magnetic bubble memories, and integrated circuits, light emission of LEDs, fluorescent lamps, organic EL elements, plasma displays, and the like.

  Hereinafter, the present invention will be described by way of examples, but the present invention is not limited to the embodiments shown in the examples.

[Example 1]
Formation of Photoresist Film 2 g of cyanine dye (Exemplary Compound A-57, λmax of film: 448 nm, thermal decomposition temperature: 275 ° C.) was dissolved in 100 ml of tetrafluoropropanol (TFP), and a disk-shaped silicon substrate (thickness 0) (6 mm, outer diameter 120 mm, inner diameter 15 mm), and a coating film was formed by spin coating. In spin coating, the coating liquid was dispensed on the inner periphery of the substrate at a coating start rotation speed of 500 rpm and a coating end rotation speed of 100 rpm, and the coating film was dried by gradually increasing the rotation speed to 2200 rpm. The thickness of the formed coating film was 100 nm.
The silicon substrate on which the coating film was formed was placed in NEO500 (wavelength: 405 nm, NA: 0.65) manufactured by Pulstec Industrial Co., Ltd., and laser light was irradiated toward the coating film surface. The laser light irradiation conditions were as follows. In the coating film, pits were formed at a pitch of 0.5 μm.
Laser power: 2mW
Line speed: 5m / s
Recording signal: 5 MHz rectangular wave

[Example 2]
A photoresist film on a silicon substrate in the same manner as in Example 1 except that the dye used was changed from a cyanine dye to a styryl dye (Exemplary Compound B-1, λmax of film: 543 nm, thermal decomposition temperature: 280 ° C.) Formed. When this resist film was irradiated with laser light in the same manner as in Example 1, pits were formed at a pitch of 0.5 μm in the resist film.

[Examples 3 and 4]
Convex and concave formation The silicon substrates treated in Examples 1 and 2 were each subjected to RIE etching from the coating film forming surface side under the following conditions, and then the coating film was removed using ethanol as a stripping solution. It was visually confirmed that fine unevenness was formed on the surface of the silicon substrate where the coating film was removed. This result shows that the coating film processed in Examples 1 and 2 functioned as an etching mask.
Etching gas: SF6 + CHF ₃ (1: 1)
Etching depth: 50 nm

[Examples 5 to 12]
Except that the cyanine dye or styryl dye described in Table 1 below was used as the dye, the surface of the resist film was irradiated with laser light in the same manner as in Example 1. As in Example 1, the resist film was applied at a pitch of 0.5 μm. A pit was formed.

[Examples 13 to 20]
RIE etching was performed in the same manner as in Example 3 using the silicon substrate having the resist film formed with pits obtained in Examples 5 to 12, and then the coating film was removed using ethanol as a peeling solution. It was visually confirmed that fine irregularities were formed on the surface of the substrate as in Example 3. From this result, it can be seen that also in the cyanine dye and styryl dye used in Examples 5 to 12, the resist film functioned as an etching mask. The example using the dye having λmax in the range of the wavelength (405 nm) ± 150 nm of the laser beam had a better pit shape than the example using the dye having λmax outside the above range.

  According to the present invention, fine surface processing can be easily performed.

Claims (7)

A photoresist solution containing 100% by mass of a compound for photoresist, which is a compound selected from the group consisting of a cyanine dye and a styryl dye, based on the total solid content. The photoresist compound includes a nitrogen-containing heterocycle selected from the group consisting of benzoxazole, benzothiazole, indolenine, which may have a substituent, and those further condensed. The photoresist liquid as described. The photoresist solution according to claim 1, wherein the photoresist compound is a cyanine dye represented by the following general formula (I).
[In the general formula (I), Z ¹ and Z ² each represents a group of nonmetallic atoms necessary for forming a 5-membered or 6-membered nitrogen-containing heterocycle, which may be independently condensed, and L ¹ , L ² and L ³ each independently represent a methine chain, m represents an integer in the range of 0 to 2, R ¹ and R ² each independently represent a substituent, and m represents 2 A plurality of L ² and L ³ may be the same or different. p and q each independently represent 0 or 1, and R ¹¹ , R ¹² , R ¹³ and R ¹⁴ each independently represent a hydrogen atom or a substituent. X ¹ represents a counter ion that neutralizes the charge of the compound represented by formula (I). ] The photoresist solution according to claim 1, wherein the photoresist compound is a styryl dye represented by the following general formula (II).
[In the general formula (II), Z ³ represents a group of nonmetallic atoms necessary for forming a 5- or 6-membered nitrogen-containing heterocycle which may be condensed, and L ⁴ and L ⁵ are Independently represents a methine chain, R ³ , R ⁴ , R ⁵ and R ⁶ each independently represent a substituent, n represents an integer in the range of 0 to 4, and when n is 2 or more, a plurality thereof is present. R ⁶ may be the same or different. r represents 0 or 1, and R ¹⁵ and R ¹⁶ each independently represents a hydrogen atom or a substituent. X ² represents a counter ion that neutralizes the charge of the compound represented by formula (II). ] The photoresist liquid according to claim 1, wherein the photoresist compound has a thermal decomposition temperature of 100 ° C. or more and 600 ° C. or less. Applying the photoresist solution according to any one of claims 1 to 5 to a surface to be processed to form a photoresist film;
Pattern exposure to the photoresist film; and
Etching at least a part of the processing surface having the photoresist film after the pattern exposure, and etching at least a part of the processing surface in a region corresponding to the part exposed in the pattern exposure. Process surface etching method. The light used for the pattern exposure is laser light having a wavelength of λ nm, and the maximum absorption wavelength λmax of the photoresist compound contained in the photoresist film is in the range of λ ± 150 nm. Etching method of the surface to be processed.