JP2006003668A - Method for cleaning transparent permanent film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve problems that in a developing process of a permanent transparent photosensitive resist, a developing solution component used in a developing solution permeates the surface layer of the photosensitive resist film or deposits on the surface of the photosensitive resist film and that the depositing developing solution component is not sufficiently removed in a rinsing step with pure water and causes coloring in a heating step, and to provide a method for cleaning after developing so as to provide a photosensitive resist film with excellent transparency. <P>SOLUTION: The method for cleaning a transparent permanent film includes a step of supplying an acidic aqueous solution to a photosensitive resist film after being exposed and developed in a patterning step of the photosensitive resist. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention has transparency such as a semiconductor integrated circuit, a thin film transistor (TFT) circuit for a liquid crystal display (LCD), a photosensitive resist for forming a mask for manufacturing a circuit, or an interlayer insulating film and a protective film for a color filter. The present invention relates to a cleaning method after development of a required material for forming a permanent film.

  In the liquid crystal display (LCD) industry, which has been rapidly developing in recent years, an active matrix type liquid crystal display (AM-LCD) in which a thin film transistor (TFT) is incorporated in each pixel is particularly a CRT (CRT) because of its fast response speed. ) Is regarded as a favorite of the next generation display device, and it is desired to enlarge the display screen.

  Incidentally, the TFT circuit of the AM-LCD is generally formed using a photosensitive resist capable of obtaining a resolution of several microns. As described above, in order to improve the display performance and quality of the liquid crystal display, the photosensitive resist is required to have high transparency.

  Further, when manufacturing a liquid crystal display, in addition to the AM-LCD circuit as described above, a permanent film such as an interlayer insulating film and a color filter protective film which are conventionally formed using a thermosetting resin is photosensitive. Attempts have been actively made to form a resist.

  In order to form a permanent film such as an interlayer insulating film and a protective film of such a liquid crystal display, a photosensitive resist having excellent transparency that greatly affects the display performance is required. However, even if a conventional positive photosensitive resist containing a novolac resin and a quinonediazide compound is used, the transparency is particularly insufficient, in addition to heat resistance and solvent resistance (Patent Document 1, Patent Document 2, Patent Document 3).

  Therefore, in recent years, photosensitive resists using highly heat-resistant transparent resins instead of phenolic resins have been developed and used as permanent films in many liquid crystal displays, particularly transmissive and transflective liquid crystal displays where transparency is important. . Recently, in order to further improve the display performance and quality of the liquid crystal display, further transparency is required for the photosensitive resist (Patent Documents 4 and 5).

JP-A-62-35349 JP-A-1-142548 JP-A-1-179147 JP-A-7-248629 JP 2003-89716 A

  On the other hand, since the photosensitive resist film is required to have durability as a permanent material, a curing process by heat is performed after patterning. However, there is a problem that coloring occurs at that time, and the transparency of the photosensitive resist film is lowered. Furthermore, when various inorganic films are laminated and formed on the heat-cured photosensitive resist film, the film is exposed to a high temperature for a long time, so that there is a problem that coloring is more likely to occur. This is because when a photosensitive resist for forming a permanent transparent film is developed, tetramethylammonium hydroxide (organic amine), which is a developer component used in a standard developer, is the surface layer of the photosensitive resist film. This is due to the fact that it penetrates into the surface or adheres to the surface of the photosensitive resist film and causes coloration in the subsequent heating step.

  That is, the developer component that permeates and adheres to the surface layer and surface of the photosensitive resist film at the time of development cannot be sufficiently removed even in the rinsing process with pure water, and is considered to be a coloring factor in the heating process.

  The present invention has been made to solve the above-described conventional problems, and an object of the present invention is to propose a post-development cleaning treatment method useful for improving the transparency of a photosensitive resist for a permanent film.

  As a result of intensive studies to solve such problems, the present inventors have developed development remaining in the photosensitive resist film by washing with an acidic aqueous solution after the development processing in the patterning process of the photosensitive resist. The present inventors have found that it is possible to neutralize and remove the liquid component and remove the coloring factor during the subsequent heat treatment, and the present invention has been completed.

  That is, the present invention relates to a method for cleaning a transparent permanent film, which includes a step of supplying an acidic aqueous solution to the photosensitive resist film subjected to exposure and development in the patterning process of the photosensitive resist to perform a cleaning process.

  By incorporating the cleaning treatment method of the present invention as a post-development treatment of the photosensitive resin composition, a permanent film having excellent transparency is provided. Furthermore, since this cured film is an organic coating film, it has a low dielectric constant and is heat-cured, so it has excellent heat resistance and resistance to various chemicals such as acids, alkalis and solvents. Therefore, the permanent film prepared by incorporating the cleaning treatment method of the present invention can be used for many applications. For example, a material for a protective film of an electronic component (for example, a material for forming a protective film used for a liquid crystal display element including a color filter, an integrated circuit element, a solid-state image sensor); a material for forming an interlayer insulating and / or planarizing film A solder photosensitive resist used in the manufacture of printed wiring boards; or a method for treating an alkali-soluble photosensitive composition suitable for forming a columnar spacer that can be used as a substitute for a bead spacer in a liquid crystal display device; . Furthermore, the cleaning treatment method of the present invention includes various optical components (lenses, LEDs, plastic films, substrates, optical disks, etc.); coating agents for forming a protective film for the optical components; adhesives for optical components (adhesives for optical fibers, etc.) ); Coating agent for producing a polarizing plate; In a hologram recording material, it is suitably used as a formulation for improving transparency.

Hereinafter, the contents of the present invention will be described in detail.
The present invention relates to a method for cleaning a transparent permanent film, which includes a step of supplying an acidic aqueous solution to perform a cleaning process on an exposed and developed photosensitive resist film in a photosensitive resist patterning process.

  In the cleaning treatment method of the present invention, treatment with an acidic aqueous solution is performed instead of pure water rinsing after the developer treatment, and then the pure water is washed and dried. Alternatively, pure water rinsing and drying may be performed once after the development processing, and then processing may be performed with an acidic aqueous solution, followed by cleaning with pure water and drying.

  The acidic aqueous solution is not limited as long as it is a dilute aqueous solution such as hydrochloric acid, nitric acid, and acetic acid, or an aqueous solution that exhibits acidity, such as carbonated water blown with carbon dioxide. Moreover, they may be used independently or may be used in mixture of 2 or more types.

The concentration of the acid component in the acidic aqueous solution is preferably in the range of 0.01 to 10% by weight, and more preferably in the range of 0.05 to 5% by weight. If the concentration of the acidic aqueous solution is less than 0.01% by weight, the neutralizing ability of the developer remaining on the resist surface is poor, and a sufficient effect cannot be obtained in improving the transparency. Conversely, when the concentration is 10% by weight or more, the photosensitive resist film may be damaged, which is not preferable. Furthermore, the treatment time of the acidic aqueous solution is preferably 5 seconds to 10 minutes, and more preferably 30 seconds to 5 minutes. As a treatment method using an acidic aqueous solution, a liquid filling method, a shower method, a dipping method, or the like can be used. After the treatment with the acidic aqueous solution, pure water rinsing is performed for 30 to 90 seconds by running water, a shower method, a dipping method, etc., the acidic aqueous solution is removed, and the treatment is completed by air drying with compressed air or compressed nitrogen.

  As a method for producing a photosensitive resist that is treated with an acidic aqueous solution in the present invention, for example, an alkali-soluble resin is dissolved in a solvent, a photosensitive agent is used as a radiation-reactive compound in this solution, and various crosslinking agents as required. By mixing various components such as a sensitizer and a surfactant in a predetermined ratio, a liquid material containing each component of the photosensitive resist is obtained. For example, it is more preferable to filter this with a Millipore filter having a pore diameter of about 0.05 to 1.0 μm to obtain a uniform liquid.

  A coating film can be formed by applying the liquid photosensitive resist thus obtained to the substrate surface and removing the solvent by means such as heating. The method for applying the photosensitive resist solution to the substrate surface is not particularly limited, and various methods such as a spray method, a roll coating method, and a spin coating method can be employed.

  Next, this coating film is usually heated (prebaked). Although the heating conditions vary depending on the type of each component, the blending ratio, etc., it is usually 70-120 ° C., and for a predetermined time, for example, 1-10 minutes on a hot plate, and 10-30 minutes in an oven, the thin film Can be obtained.

  Next, the pre-baked coating film is irradiated with radiation, for example, ultraviolet rays through a mask having a predetermined pattern. This changes the radiation-reactive compound. In the case of a composition containing a quinonediazide compound, the diazo group portion of the compound is changed to carboxylic acid and becomes alkali-soluble. Therefore, the solubility with respect to the alkali of the whole composition becomes high by irradiation, compared with before irradiation. Therefore, for example, development is possible by using a developer containing an alkali at an appropriate concentration. In the case of a negative resist containing a photopolymerization initiator or the like, the solubility in alkali decreases due to the progress of the cross-linking reaction due to irradiation, giving a negative pattern. Further, in the case of a chemically amplified negative resist containing an acid generator or the like, crosslinking can be promoted by heating (post-exposure baking) after irradiation.

  Next, unnecessary portions are removed with an appropriate developer to form a film having a predetermined pattern. As the developer, an aqueous solution containing an alkali is usually used. Examples of the alkali include inorganic alkalis such as sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, and aqueous ammonia; Primary amines such as n-propylamine; Secondary amines such as diethylamine and di-n-propylamine; Tertiary amines such as triethylamine and methyldiethylamine; Alcohols such as dimethylethanolamine and triethanolamine Amines; quaternary ammonium salts such as tetramethylammonium hydroxide, tetraethylammonium hydroxide, choline; pyrrole, piperidine, 1,8-diazabicyclo [5.4.0] -7-undecene, 1,5-diazabicyclo [ 4.3 0] -5-nonane and the like cyclic amines, such as.

  In addition, an aqueous solution obtained by adding an appropriate amount of a water-soluble organic solvent such as methanol or ethanol, a surfactant, or the like to the alkaline aqueous solution can also be used as a developer. The development time is usually 30 to 180 seconds, and as a development method, a liquid piling method, a shower method, a dipping method, or the like can be used. After the development, washing with running water is performed for 30 to 90 seconds, unnecessary portions are removed, and the pattern is formed by air drying with compressed air or compressed nitrogen. Then, it processes with acidic aqueous solution and rinses with a pure water. Further, as described above, the treatment with an acidic aqueous solution may be performed immediately after immersion in the developing solution, and finally the pure water washing may be performed. Thereafter, in the case of a positive resist containing a naphthoquinonediazide-type photosensitizer, the remaining photosensitive groups are decomposed by irradiating the entire surface with ultraviolet rays to improve transparency. After that, it is patterned by heating with a heating device such as a hot plate and oven at a predetermined temperature, for example, 150 to 250 ° C., for a predetermined time, for example, 2 to 30 minutes on the hot plate, and 30 to 90 minutes in the oven. A cured film can be obtained.

  The resin component that is a raw material for producing the photosensitive resist that is treated with the acidic aqueous solution in the present invention is not particularly limited, and examples thereof include polyvinylphenol, novolac resin, and acrylic resin. Examples of the novolak resin include phenol, o-cresol, m-cresol, p-cresol, 2,5-xylenol, 3,5-xylenol, 3,4-xylenol, 2,3,5-trimethylphenol, 4- t-butylphenol, 2-t-butylphenol, 3-t-butylphenol, 3-ethylphenol, 4-ethylphenol, 3-methyl-6-t-butylphenol, 4-methyl-2-t-butylphenol, 2-naphthol, Examples thereof include resins obtained by condensing phenols such as 1,3-dihydroxynaphthalene and 1,5-dihydroxynaphthalene alone or in combination of two or more with aldehydes by a conventional method.

  Examples of aldehydes include formaldehyde aqueous solution (formalin) and paraformaldehyde. In particular, 37% formalin is industrially mass-produced and is convenient.

  Also particularly preferred as the alkali-soluble resin is the fluorene derivative described in JP-A-2003-89716, and the substrate on which the blended composition is formed exhibits excellent properties in transparency.

  As a photosensitizer that is a raw material for producing a positive photosensitive resist that is processed with an acidic aqueous solution in the present invention, any photosensitizing agent that has a property that the diazo moiety in the compound is converted into a carboxylic acid by irradiation and becomes alkali-soluble can be used. Not particularly limited, 2,3,4-trihydroxybenzophenone-1,2-naphthoquinonediazide-5-sulfonic acid ester, 2,3,4,4′-tetrahydroxybenzophenone-1,2-naphthoquinonediazide-5 A sulfonic acid ester (THBP-NQD) and the like can be mentioned, and the quinone diazide sulfonic acid ester and the like can be used without being particularly limited thereto. The photosensitizers may be used alone or in combination of two or more.

  The compounding ratio of the positive photosensitive agent used in the present invention may be a ratio usually used, and the lower limit is usually 1 part by weight or more, preferably 3 parts by weight or more, more preferably 5 parts by weight with respect to 100 parts by weight of the alkali-soluble resin. The upper limit is usually 100 parts by weight or less, preferably 80 parts by weight or less, more preferably 40 parts by weight or less. If the blending ratio is too small, a sufficient remaining film ratio cannot be obtained, resulting in degradation of resolution, and conversely, if the blending ratio is too large, sensitivity is lowered, which is not preferable.

  The crosslinking agent that can be used as a raw material for producing a photosensitive resist that is treated with an acidic aqueous solution in the present invention is formed into a thin film on a substrate using the composition, exposed to light and developed, and then heated to be alkali-soluble. It has a function of cross-linking resins and is contained to strengthen the thin film after development. Examples of such cross-linking agents include melamines; glycolurils; and compounds having at least two epoxy groups in the molecule.

  When the crosslinking agent is a melamine or glycoluril, the crosslinking agent is preferably contained in an amount of 1 to 100 parts by weight with respect to 100 parts by weight of the alkali-soluble resin, and 5 to 50 parts by weight. More preferably, it is contained.

  The sensitizer that can be used as a raw material for producing a photosensitive resist that is treated with an acidic aqueous solution in the present invention is used for improving the sensitivity of the photosensitive agent to radiation. Examples of such sensitizers include 2H-pyrido- (3,2-b) -1,4-oxazin-3 (4H) -ones, 10H-pyrido- (3,2-b) -1 , 4-benzothiazines, urazoles, hydantoins, barbituric acids, glycine anhydrides, 1-hydroxybenzotriazoles, alloxans, maleimides and the like. These may be used alone or in combination of two or more.

  Such a sensitizer is usually contained in a proportion of 100 parts by weight or less, preferably 4 to 60 parts by weight, with respect to 100 parts by weight of the photosensitive agent.

  The surfactant that can be used as a raw material for producing a photosensitive resist that is treated with an acidic aqueous solution in the present invention is, for example, a striation (after coating) when a photosensitive resist containing a solvent is applied on a substrate. It is contained in order to prevent and improve the coatability or to improve the developability of the coating film.

  Examples of such surfactants include the following compounds or products: polyoxyethylene alkyl ethers such as polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, and polyoxyethylene oleyl ether; polyoxyethylene octylphenyl ether Polyoxyethylene aryl ethers such as polyoxyethylene nonylphenyl ether; nonionic surfactants such as polyoxyethylene dialkyl esters such as polyoxyethylene dilaurate and polyoxyethylene distearate; Ftop EF301, Ftop 303 F-top 352 (manufactured by Shin-Akita Kasei Co., Ltd.); Megafuck F171, Megafuck F172, Megafuck F173 (Dainippon Ink Chemical Co., Ltd.); Flora De FC-430, Florard FC-431 (manufactured by Sumitomo 3M); Asahi Guard AG710, Surflon S-382, Surflon SC-101, Surflon SC-102, Surflon SC-103, Surflon SC-104, Surflon SC- 105, fluorosurfactant marketed under the name of Surflon SC-106 (Asahi Glass Co., Ltd.); organosiloxane polymer KP341 (manufactured by Shin-Etsu Chemical Co., Ltd.); (meth) acrylic acid copolymer Polyflow No. 57, 95 (manufactured by Kyoeisha Yushi Chemical Co., Ltd.). These may be used alone or in combination of two or more.

  Such a surfactant is contained in an amount of 2% by weight or less, preferably 1% by weight or less of the entire photosensitive resist.

  The solvent used for the manufacturing raw material of the photosensitive resist which processes with the acidic aqueous solution in this invention melt | dissolves each component in a composition uniformly, for example, is used in order to make the coating on a board | substrate easy. Such a solvent is not particularly limited as long as it is an organic solvent that does not react with each component in the composition and can dissolve or disperse them. Examples of the solvent include the following compounds: alcohols such as methanol and ethanol; ethers such as tetrahydrofuran; glycol ethers such as ethylene glycol monomethyl ether, ethylene glycol dimethyl ether, ethylene glycol methyl ethyl ether, and ethylene glycol monoethyl ether. Ethylene glycol monoethyl ether acetate, methyl cellosolve acetate, ethylene glycol alkyl ether acetates such as ethyl cellosolve acetate; diethylene glycol monomethyl ether, diethylene glycol diethyl ether, diethylene glycol dimethyl ether, diethylene glycol ethyl methyl ether, diethylene glycol monoethyl ether, diethylene glycol Diethylene glycols such as rumonobutyl ether; propylene glycol alkyl ether acetates such as propylene glycol monomethyl ether acetate and propylene glycol monoethyl ether acetate; aromatic hydrocarbons such as toluene and xylene; methyl ethyl ketone, methyl amyl ketone, cyclohexanone, 4-hydroxy Ketones such as -4-methyl-2-pentanone; and ethyl 2-hydroxypropionate, methyl 2-hydroxy-2-methylpropionate, ethyl 2-hydroxy-2-methylpropionate, ethyl ethoxyacetate, ethyl hydroxyacetate , Methyl 2-hydroxy-2-methylbutanoate, methyl 3-methoxypropionate, ethyl 3-methoxypropionate, 3-ethoxypropion Methyl, ethyl 3-ethoxypropionate, ethyl acetate, butyl acetate, esters such as methyl lactate, ethyl lactate. These solvents may be used alone or in combination of two or more.

  EXAMPLES Hereinafter, although this invention is demonstrated concretely based on an Example and a comparative example, this invention is not limited to this Example. In the following Examples and Comparative Examples, “part” means “part by weight”.

(Examples 1-4, Comparative Example 1)
Alkali-soluble resin: 70 parts by weight, 2,3,4,4′-tetrahydroxybenzophenone compound obtained by esterifying 3.5 mol of 1,2-naphthoquinonediazide-5-sulfonyl as a photosensitizer: 20 parts by weight, crosslinked As the agent, TECHMORE VG3101: 10 parts by weight manufactured by Mitsui Chemicals, Inc. was dissolved in propylene glycol monomethyl ether acetate so that the solid content concentration was 30 wt%. This was filtered through a Millipore filter having a pore size of 0.2 μm.

  Using the obtained solution, a pattern was formed on the substrate according to the pattern forming method shown in (1) below. About the formation process of a pattern and the obtained pattern, it tested about the item shown in following (2).

(1) Pattern formation method The solution obtained above was applied to a glass substrate (disk shape) having a diameter of 4 inches using a spinner, and then pre-baked on a hot plate at 90 ° C. for 2 minutes to obtain a film thickness of 2. A 0 μm coating film is formed. The obtained coating film was exposed with a predetermined amount of energy through a mask having a predetermined pattern using a Canon PLA-501F contact exposure machine, and then a 0.4% by weight tetramethylammonium hydroxide (TMAH) aqueous solution was added. And develop at 23 ° C. for 60 seconds. Next, a pattern is formed on the glass substrate by rinsing with water and drying.

(2) Evaluation method The glass substrate having the pattern obtained in the above step is immersed in a 0.1 wt% aqueous hydrochloric acid solution for 60 seconds. Next, after rinsing with water and drying, irradiation with ultraviolet light having a light intensity of 9.5 mW at 405 nm is performed so as to be 500 mJ / cm ² . Next, the transmittance of the obtained pattern part on the glass substrate is measured at a wavelength of 400 to 700 nm using a spectrophotometer “UV-2100PC (manufactured by Shimadzu Corporation)”.
Further, the substrate was heated in a clean oven at 240 ° C. for 60 minutes, the transmittance was measured in the same manner, and evaluated as follows:
A: The minimum transmittance is 97% or more. B: The minimum transmittance is 95% to less than 97%. Δ: The minimum transmittance is 90% to less than 95%.

Table 1 shows the compositions and evaluation results of the photosensitive resist solutions used in the examples and comparative examples.

  As is apparent from Table 1, the treatment method of the present invention is effective in improving transparency regardless of the type of heat-resistant transparent resin, and can provide a coating (pattern) excellent in transparency.

  Therefore, the cleaning treatment method of the present invention is useful as a permanent film forming material that requires transparency, such as a photosensitive resist material, an interlayer insulating film, and a protective film for manufacturing TFT circuits for LCDs.

Claims (1)

A method for cleaning a transparent permanent film, comprising a step of supplying an acidic aqueous solution to perform a cleaning process on an exposed and developed photosensitive resist film in a photosensitive resist patterning process.