JP6054104B2 - Reaction development image forming method - Google Patents

Description

  The present invention relates to a photoresist technique that can be used for manufacturing a semiconductor integrated circuit, a printed wiring board, a liquid crystal panel, and the like. More specifically, the present invention relates to a photo resist film formed using a photosensitive resin composition containing a polyimide resin. The present invention relates to a photoresist technique in which a positive image is formed through irradiation and a development process.

Photoresists are commonly used in photolithographic organic polymers used in the related art in photographic deck processing, for the production of printed circuit boards and printed circuit boards, or for the production of semiconductor laminates in microelectronics. .
In order to create circuit structures in the manufacture of microelectronic semiconductor integrated components, the semiconductor substrate is imaged with a photoresist layer coated with a photoresist and subsequent development creates a photoresist relief structure. This relief structure is used on a semiconductor substrate as a mask for creating an actual circuit pattern by etching-doping or coating using a metal or other semiconductor or insulating substrate. Thereafter, the photoresist mask is usually removed. A microchip relief structure is formed on the substrate using a plurality of such processing cycles. There are positive and negative photoresists, the exposed areas of positive photoresist are removed by the development process, the unexposed areas remain as a layer on the substrate, and the exposed areas of negative working photoresist are relief structures. Remain as.
The present inventors use a polymer having an imide group in the main chain, and form a negative photoresist using a diazonaphthoquinone compound as a photoacid generator and an N-substituted maleimide compound as an anion regenerant. "Reactive development image forming method" was developed (Patent Documents 1 and 2).
In addition, a method of forming a positive photoresist with high resolution using polyimide having an alicyclic portion is disclosed (Patent Document 3).

JP2007-328333 JP2011-53366 JP2001-261826

  The present invention improves the “reactive development image forming method” (Patent Documents 1 and 2) for forming a photoresist based on a polyimide resin, uses an alkaline aqueous solution as a developer, and undergoes a development process with a short development time. A photoresist technique for forming a positive image is provided.

  The inventors of the present invention have developed a photosensitive resin containing an acid dianhydride and a low molecular weight diamine compound, wherein the acid dianhydride contains an alicyclic acid dianhydride and a photoacid generator. It was found that a positive type photoresist can be formed in a short development time when a film is formed using a conductive resin composition, developed with ultraviolet light, and developed using a developer comprising an alkaline aqueous solution.

That is, the present invention is a photosensitive resin composition for forming a positive photoresist structure containing a polyimide resin and a photoacid generator, wherein the polyimide resin comprises an acid dianhydride and the following formula:
(In the formula, R ¹ represents a hydrocarbon group having 6 or less carbon atoms, R ² independently represents a hydrogen atom, a fluorine atom, an alkyl group, an alkoxy group or a fluoroalkyl group, and n is 0. Wherein n is less than or equal to the carbon number of R ¹ ), and the acid dianhydride containing alicyclic acid dianhydride is reacted. It is a resin composition.
The present invention also provides a step of providing a photoresist layer containing the photosensitive resin composition on a substrate, masking it with a desired pattern, irradiating the pattern surface with ultraviolet rays, and applying the photoresist layer to a developer. And a developing step, wherein the developing solution is an alkaline aqueous solution to form a positive photoresist.
Moreover, this invention is a positive type photoresist structure which has a photoresist layer formed by said method on the board | substrate, and the film thickness of this photoresist layer is 0.1-500 micrometers. A relief structure having a desired pattern can be formed as the photoresist layer.

It is a figure which shows the thermal-analysis result of the polyimide resin produced in the manufacture example 1. FIG. A shows a differential scanning calorimetry (DSC) graph, and B shows a thermogravimetric-differential thermal analysis (TG-DTA) graph. It is a figure which shows the SEM photograph of the formed photoresist. A to E are those of Examples 1 to 5, respectively. The test pattern in the figure has a line and space of 30 μm.

The photosensitive resin composition used in the present invention comprises a polyimide resin and a photoacid generator, and may further contain an alkali dissolution accelerator.
This polyimide resin is obtained by dehydrating and cyclizing a polyamic acid (polyamic acid), which is a polyimide precursor obtained by polymerizing an acid dianhydride and a low molecular weight diamine compound.
The acid dianhydride used in the present invention is characterized by containing an alicyclic acid dianhydride. The acid dianhydride may be a mixture of an alicyclic acid dianhydride and an aromatic acid dianhydride. The ratio of the alicyclic acid dianhydride to the aromatic acid dianhydride (molar ratio, alicyclic acid dianhydride: aromatic acid dianhydride) is preferably 8: 2 to 4: 6. Preferably it is 7.5: 2.5-4.5: 5.5, More preferably, it is 6: 4-5: 5.
The polyimide resin has an imidization ratio (referring to an imide cyclization ratio of polyamic acid) of preferably 90% or more, and more preferably 95% or more.
A preferred example of the polyimide resin is obtained from a polyamic acid synthesized from the following acid dianhydride A as an alicyclic acid dianhydride and the following acid dianhydride B as an aromatic acid dianhydride and the following diamine compound. A polyimide resin is mentioned.

Examples of the acid dianhydride A include a compound represented by the following formula, or BuDA, MCTC, DTDA, or EtDA, and a compound represented by the following formula is preferred.

In the formula, R ³ represents a tetravalent alicyclic substituent. Examples of the tetravalent alicyclic substituent include a substituent represented by the following formula. Among these, BOEDA, CHDA, CBDA, TMCBDA, CPDA and TFDA are preferable, and since the number of carbon atoms in the substituent is small, the hydrophobicity is low, and the affinity with an alkaline aqueous solution as a developer is high, so CBDA is particularly preferable.

Acid dianhydride B is represented by the following formula.
In the formula, R ⁴ represents a substituent represented by the following formula.
The ratio of the acid dianhydride A to the acid dianhydride B (molar ratio A: B) is preferably 8: 2 to 4: 6, more preferably 7.5: 2.5 to 4.5: 5. .5, more preferably 6: 4 to 5: 5.

  Examples of the acid dianhydride A include bicyclo [2.2.2] oct-7-ene-2,3,5,6-tetracarboxylic dianhydride (hereinafter referred to as “BOEDA”), 1,2,4. , 5-cyclohexanetetracarboxylic dianhydride (hereinafter referred to as “CHDA”), 1,2,3,4-cyclohexanetetracarboxylic dianhydride (hereinafter referred to as “34CHDA”), 1,2,3 , 4-cyclobutanetetracarboxylic dianhydride (hereinafter referred to as “CBDA”), 1,2,3,4-tetramethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride (hereinafter referred to as “ TMCBDA ”), 1,2,3,4-cyclopentanetetracarboxylic dianhydride (hereinafter referred to as“ CPDA ”), tetrahydrofuran-2,3,4,5-tetracarboxylic dianhydride (hereinafter referred to as“ CPDA ”). , "TFDA"), methanetetraacetic acid dianhydride (hereinafter referred to as "MeDA"), butane-1,2,3,4-tetracarboxylic dianhydride (hereinafter referred to as "BuDA"), 5- (2,5 -Dioxotetrahydrofuryl) -3-methyl-3-cyclohexene-1,2-dicarboxylic anhydride (hereinafter referred to as “MCTC”), 4- (2,5-dioxotetrahydrofuran-3-yl) -tetralin -1,2-dicarboxylic anhydride (hereinafter referred to as “DTDA”), ethane-1,1,2,2, -tetracarboxylic dianhydride (hereinafter referred to as “EtDA”), and the like.

  Examples of the acid dianhydride B include 3,3 ′, 4,4′-diphenylsulfonetetracarboxylic dianhydride (hereinafter referred to as “DSDA”), 3,3 ′, 4,4′-benzophenone tetracarboxylic acid. Acid dianhydride (hereinafter referred to as “BTDA”), 4,4 ′-(hexafluoroisopropylidene) bis (phthalic anhydride) (hereinafter referred to as “6FDA”), and the like. These may be used individually by 1 type and may be used in combination of 2 or more type.

The diamine compound used in the present invention needs to have a low molecular weight from the viewpoint of solubility of the exposed polymer in a developer. This diamine compound is represented by the following formula.
In the formula, R ¹ represents a hydrocarbon group having 6 or less carbon atoms. Examples of the hydrocarbon group having 6 or less carbon atoms include a phenylene group, a cyclohexylene group, and an aliphatic hydrocarbon group having 6 or less carbon atoms. This aliphatic hydrocarbon group is preferably a saturated aliphatic hydrocarbon group.
R ² independently represents a hydrogen atom, a fluorine atom, an alkyl group, an alkoxy group or a fluoroalkyl group. The alkyl group, alkoxy group and fluoroalkyl group preferably have 5 or less carbon atoms, more preferably 3 or less. More preferably, this alkyl group is represented by — (CH ₂ ) _m CH ₃ , and this alkoxy group is represented by —O (CH ₂ ) _m CH ₃ (wherein m is preferably 0 to 4, more preferably 0). Represents an integer of ~ 2).
n represents an integer of 0 to 4. Here, n is less than the number of carbon atoms in ^{R 1.}

This diamine compound is preferably represented by the following formula.
In the formula, R ² and n are the same as described above. However, n is preferably an integer of 1 to 4.

  Examples of the diamine compound represented by the above chemical formula (Chemical Formula 5) include 1,3-phenylenediamine, 1,4-phenylenediamine, 1,4-diamino-2,3,5,6-tetramethylbenzene, 1,4 -Diamino-2,3,5-trimethylbenzene, 1,4-diamino-2,5-dimethylbenzene, 1,4-diamino-2,6-dimethylbenzene, 2,5-diaminotoluene, 2,4-diamino Toluene (hereinafter referred to as “DAT”), 1,3-diamino-4,5-dimethylbenzene, 1,3-diamino-4,6-dimethylbenzene, 1,3-diamino-4,5,6-trimethyl Benzene, 1,3-diamino-2,4,5,6-tetramethylbenzene, 2-ethyl-1,4-benzenediamine, 2,5-diethyl-1,4-benzenediamine, 2,6-diethyl- 1,4-benzenediamine, 4-ethyl-1,3-benzenediamine, 2-propyl-1,4-benzenediamine, 4-propyl-1,3-benzenediamine, 2-methoxy-1,4-benzenediamine 2,5-dimethoxy-1 , 4-Benzenediamine, 4-methoxy-1,3-benzenediamine, 4-ethoxy-1,3-benzenediamine, 2,3-dihydro-1,4-benzodioxin-5,8-diamine, 2-fluoro -1,4-benzenediamine, 2,6-difluoro-1,4-benzenediamine, 2,3,5,6-tetrafluoro-1,4-benzenediamine, 2-fluoro-1,4-benzenediamine, 2,4,5,6-tetrafluoro-1,3-benzenediamine, 2-trifluoromethyl-1,4-benzenediamine, 2,5-bis (trifluoromethyl) -1,4-benzenediamine, 4 -Trifluoromethyl-1,3-benzenediamine and the like.

Examples of the diamine compound in which R ^{1 in the} general formula (Chemical Formula 1) is an aliphatic hydrocarbon group having 6 or less carbon atoms include ethylenediamine and 1,2-diaminopropane.
In addition, the said diamine compound may be used individually by 1 type, and may be used in combination of 2 or more type.

The polyimide resin can be synthesized from the above acid dianhydride and diamine compound by the following method.
An acid dianhydride and a diamine compound are dissolved in an organic solvent. As the organic solvent, a solvent in which the acid dianhydride, the diamine, and the produced polymer are all dissolved is used. Γ-Valerolactone and pyridine which are catalysts are added to the resulting solution, and toluene is further added. Toluene is used for azeotropic removal of water produced by the polymerization reaction, and is added in a small amount (so that precipitation and turbidity do not occur). The resulting solution is heated and stirred under a nitrogen atmosphere. The heating temperature is about 150 to 250 ° C., preferably 170 to 200 ° C., more preferably 180 ° C. in terms of bath temperature. The stirring speed is 150 to 250 rpm, preferably 170 to 200 rpm, more preferably 180 rpm. Although the heating time depends on the degree of progress of the polymerization reaction, it is adjusted to 4 to 20 hours. The reaction solution is poured into about 20 times the amount of methanol, and the resulting solid is heated and dried under reduced pressure to obtain a polyimide resin. Polyamic acid (polyamic acid), which is a polyimide precursor obtained by polymerization of acid dianhydride and diamine, is dehydrated and cyclized by high-temperature heating (300 ° C or higher) or reaction in the presence of a catalyst. A resin may be obtained.

  The polyimide resin used in the present invention is preferably soluble in an organic solvent. For example, this polyimide resin is preferably soluble in NMP (N-methylpyrrolidone) at 60 ° C. at 17 wt% or more. The solubility of the polyimide resin in the organic solvent is determined by the content of the alicyclic acid dianhydride that is the acid dianhydride component in the polyimide resin, for example, in the mixture of the alicyclic acid dianhydride and the aromatic acid dianhydride. Depending on the ratio of the alicyclic acid dianhydride, the content of the alicyclic acid dianhydride, for example, the alicyclic acid dianhydride, so that the solubility of the polyimide resin in the organic solvent is good It is necessary to select the proportion of alicyclic dianhydride in the mixture of aromatic dianhydrides.

  The photoacid generator used in the present invention may be any one that generates acid upon light irradiation. Examples of the photoacid generator include quinonediazide compounds, onium salts, sulfonic acid esters, and organic halogen compounds. The quinonediazide compound includes 1,2-naphthoquinone-2-diazide-5-sulfonic acid or 1,2-naphthoquinone-2-diazide-4-sulfonic acid and a low-molecular aromatic hydroquinone compound such as 2,3,4-trihydroxy. Examples include benzophenone, 2,3,4,4′-tetrahydroxybenzophenone and trihydroxybenzene, such as 1,3,5-trihydroxybenzene, or an ester-forming compound of cresol. Examples of onium salts include triphenylsulfonium hexafluoroantimonate and triphenylsulfonium hexafluorophosphate. These are used with esters such as t-butyl benzoate. Among these, 1,2-naphthoquinone-2-diazide-5-sulfonic acid-p-cresol ester is particularly preferable.

The alkali dissolution accelerator used in the present invention promotes the dissolution of the polyimide resin in the exposed area in an alkaline aqueous solution (that is, a developer). Examples of the alkali dissolution accelerator include alkyl sulfonic acid, aryl sulfonic acid, alkyl carboxylic acid, and aryl carboxylic acid.
Examples of the alkyl sulfonic acid include methane sulfonic acid and butane sulfonic acid.
Examples of the aryl sulfonic acid include p-toluene sulfonic acid, benzene sulfonic acid, and hydroxybenzene sulfonic acid.
Examples of the alkyl carboxylic acid include butyric acid, valeric acid, and stearic acid. Examples of the aryl carboxylic acid include aryl carboxylic acid: benzoic acid, 5-hydroxyisophthalic acid, 1,4-naphthalenedicarboxylic acid, Examples include 2,6-naphthalenedicarboxylic acid and 2-naphthalenecarboxylic acid.
Among these, aryl sulfonic acid and aryl carboxylic acid are preferable. As aryl sulfonic acid, hydroxybenzene sulfonic acid, as aryl carboxylic acid, aryl carboxylic acid: benzoic acid, 5-hydroxyisophthalic acid, 1,4- Naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, and 2-naphthalenecarboxylic acid are preferable. Of these, hydroxybenzenesulfonic acid and 5-hydroxyisophthalic acid are particularly preferred.

The photoacid generator is used in the photoresist in an amount of 5 to 50% by weight, preferably 10 to 40% by weight, more preferably 20 to 30% by weight based on the total solid content.
The alkali dissolution accelerator is usually used in an amount of 1 to 40 parts by weight, preferably 3 to 20 parts by weight, based on 100 parts by weight of the polyimide resin.

The photosensitive resin composition of the present invention may further contain additives such as a coupling agent, a leveling agent, a plasticizer, another film-forming resin, a surfactant, and a stabilizer. Even when all of these additives are combined, the amount does not exceed 25% by weight based on the total solid content of the photosensitive resin composition.
The photosensitive resin composition of the present invention is blended by mixing or dissolving the components in a solvent or solvent mixture by a method known per se. Once the components are dissolved in the solution, the resulting photosensitive resin composition solution may be filtered using a filtration membrane having 0.1 to 1 μm pores.

  Solvents suitable for the production of the photosensitive resin composition solution are, in principle, sufficiently soluble in the nonvolatile components of the photosensitive resin composition, such as polymers and photoacid generators and other additives, and are irreversible with these components. Any solvent that does not react with. Suitable solvents include, for example, aprotic polar solvents such as N-methyl-2-pyrrolidone (hereinafter referred to as “NMP”), butyrolactone, cyclohexanone, diacetoxyethylene glycol, sulfolane, tetramethylurea, N, N-dimethyl. Acetamide, dimethylformamide, dimethyl sulfoxide, acetonitrile, diglyme, phenol, cresol, toluene, methylene chloride, chloroform, tetrahydrofuran, dioxane, acetone and the like.

A photoresist layer can be formed on a substrate using such a photosensitive resin composition solution. As the substrate, any organic material such as resin, inorganic material, metal, etc. may be used, but a copper substrate or a silicon substrate is preferable.
Coating onto the substrate is usually done by dipping, spraying, roll coating or spin coating. The resulting layer thickness depends on the viscosity, solids content and spin coating speed of the photoresist solution. The photoresist of the present invention can make a layer and a relief structure having a layer thickness of 0.1 to 500 μm, preferably 1 to 100 μm. The thin layer in the multi-layer circuit can be 1-50 μm as a temporary photoresist or as an insulating layer.
After the photoresist is applied to the substrate, it is usually pre-dried at a temperature range of 50 to 120 ° C. An oven or a heating plate can be used. The drying time in the oven is 5 to 60 minutes.

Thereafter, the photoresist layer is irradiated with ultraviolet rays after being masked with a desired pattern. Ultraviolet rays refer to electromagnetic waves having a central wavelength of 250 to 450 nm, preferably 300 to 400 nm. Usually actinic light is used, but high-energy radiation such as X-rays or electron beam rays can also be used. Direct irradiation or via an exposure mask can be performed. A radiation beam can also be applied to the surface of the photoresist layer.
Usually, radiation is performed using an ultraviolet lamp. It is preferable to use a commercially available radiation apparatus such as a contact or non-contact exposure machine, a scanning projection type exposure apparatus or a wafer stepper.

After the exposure, the photoresist layer is developed with a developer.
The developer used in the present invention does not contain an organic solvent and contains an alkali component as a main component. A preferred developer comprises only an alkali component and water.
Examples of the alkali component include KOH, NaOH, and tetra-substituted ammonium hydroxide.
This tetra-substituted ammonium hydroxide is represented by the following formula.
NR ' ₄ OH
In the formula, R ′ may be the same or different and each represents a hydrocarbon group, preferably an alkyl group, more preferably an alkyl group having 1 to 3 carbon atoms.
Preferred tetra-substituted ammonium hydroxides include tetraalkylammonium hydroxides such as tetramethylammonium hydroxide.
The alkali component concentration in the developer is 0.1 to 25% by weight, preferably 1 to 10% by weight, and more preferably 2 to 5% by weight.

Development is performed in consideration of the type of polymer and other components, the type of developer, exposure energy, type of development, preliminary drying temperature, development temperature, and development time.
You may wash | clean with a suitable solvent after image development.
The positive photoresist of the present invention can take a relief structure with a polymer film having a layer thickness of 0.1 to 500 μm, preferably 1 to 100 μm, and a sharp contour rounded.

The following examples illustrate the invention but are not intended to limit the invention.
The polyimide resin used in this example was synthesized according to a report (J. Polym. Sci. Part A: Polym. Chem., 39, 3451 (2001)). In addition, gel permeation chromatography (GPC) (Tosoh Corporation, dual pump DP-8020, UV-visible detector UV-8020 (measurement wavelength 270 nm), column TSK _gel GMH _HR -M (2), guard column TSK _guardcolumn H The molecular weight of the polyimide was measured at room temperature using _HR- H (1). Using N, N′-dimethylformamide DMF (flow rate 0.8 mL / min, DMF 1 L containing LiBr 30 mmol H ₃ PO ₄ 60 mmol) as an eluent, the number average molecular weight Mn and the weight average molecular weight Mw in terms of polystyrene are Each was decided.
In this example, a photoresist was formed by the following method. Each photoresist composition was filtered through a filter membrane having a pore size of 3 μm and applied to the surface of a copper foil having a diameter of 10 cm subjected to surface treatment by a spin coating method. Subsequently, it dried in the infrared hot air dryer. A test pattern for a positive photomask (10-200 μm line and space pattern) is placed on this photoresist composition coating film, and a 2 kW ultra-high pressure mercury lamp irradiation device (Oak Seisakusho product: JP-2000G) is used. Irradiation was performed with an exposure amount that would produce an image. The coated film after irradiation was immersed in a developer, washed with pure water, and dried with an infrared lamp.
The resolution was determined by observing the developed line and space pattern with a laser microscope (VK-8510, manufactured by Keyence Corporation). Regarding the remaining film ratio, the film thickness of the film before exposure and the exposed area after development was measured with a contact-type film thickness meter (Nikon Digi Micro MF-501), and the ratio (residual film ratio) was calculated.
The formed photoresist was observed by SEM (JEOL, scanning electron microscope: JSM-6390LV, acceleration voltage: 1.2 kV).

Production Example 1
In this production example, polyimide resin 1 (the following formula) used in Examples 1 to 3 was synthesized.
(Wherein, a and b are numbers corresponding to the degree of polymerization of the resin (= molecular weight of polymer / molecular weight of repeating unit), and satisfy the relationship of a: b = 6: 4 (molar ratio of charged base)). .)
A CHDA (1,2,4,5-cyclohexanetetracarboxylate) is added to a four-necked flask equipped with a glass stirring rod with a fluororesin plate and a condenser tube with a ball (Dean-Stark trap) equipped with a moisture separation trap. Anhydride, manufactured by Tokyo Chemical Industry Co., Ltd.) 1.35 g (6 mmol), DSDA (3,3 ′, 4,4′-diphenylsulfonetetracarboxylic dianhydride, manufactured by Tokyo Chemical Industry Co., Ltd.) 1.43 g (4 mmol), DAT ( 2,2-diaminotoluene, manufactured by Tokyo Chemical Industry Co., Ltd.) 1.22 g (10 mmol) and m-cresol 36 g were charged, 0.21 g (2.0 mmol) of γ-valerolactone, 0.32 g (4.0 mmol) of pyridine and 10 g of toluene were added, The mixture was reacted at a bath temperature of 180 ° C./180 rpm for 5 hours in a nitrogen atmosphere and reprecipitated in about 20 times the amount of methanol. The obtained solid was dried under reduced pressure at 70 ° C. overnight to obtain a polyimide resin. The resulting polyimide resin had a number average molecular weight Mn23,000, a weight average molecular weight Mw38,000, and a polydispersity Mw / Mn = 1.6.

The glass transition temperature of the polyimide resin 1 was measured by DSC (Shimadzu Corporation, DSC-60). The polyimide resin is packed in a crimp cell, heated to 400 ° C under nitrogen at a heating rate of 5 ° C / min, once cooled to room temperature, and then heated again to 400 ° C under nitrogen at a heating rate of 5 ° C / min. . The obtained result is shown in FIG. 1A. Even when heated to 400 ° C, no peak of the glass transition temperature was observed.
The heat resistance of the polyimide resin 1 was measured by TG-DTA (Shimadzu Corporation, DTG-60). The polyimide resin was packed in a platinum cell, heated to 210 ° C. at a heating rate of 10 ° C./min and maintained at 210 ° C. for 1 hour, then cooled to room temperature, and then heated again to 800 ° C. under nitrogen. The obtained result is shown in FIG. 1B. The polyimide resin 5% weight reduction temperature was 465 ° C.
From the DSC and TG-DTA measurement results, it was found that the synthesized polyimide has the same physical and chemical heat resistance as aromatic polyimide.

Production Example 2
In this production example, the polyimide resin 2 (the following formula) used in Example 4 was synthesized.
(Where c and d are numbers corresponding to the degree of polymerization of the resin (= molecular weight of the polymer / molecular weight of the repeating unit), and c: d = 5: 5 (molar ratio of charged base)) Fulfill.)
A CBDA (1,2,3,4-cyclobutanetetracarboxylic acid) was added to a four-necked flask equipped with a glass stirring rod with a fluororesin plate and a condenser tube with a ball (Dean-Stark trap) equipped with a moisture separation trap. Anhydride, manufactured by Tokyo Chemical Industry Co., Ltd.) 0.98g (5 mmol), DSDA 1.79g (5 mmol), DAT 1.22g (10 mmol), m-cresol 36g, γ-valerolactone 0.21g (2.0 mmol), pyridine 0.32 g (4.0 mmol) and 10 g of toluene were added, and the mixture was reacted at a bath temperature of 180 ° C./180 rpm for 16 hours in a nitrogen atmosphere, and reprecipitated in about 20 times the amount of methanol. The obtained solid was dried under reduced pressure at 70 ° C. overnight to obtain a polyimide resin. The resulting polyimide resin had a number average molecular weight of 17,000, a weight average molecular weight of Mw 35,000, and a polydispersity Mw / Mn = 2.0.

Production Example 3
In this production example, the polyimide resin 3 (the following formula) used in Example 5 was synthesized.
(Wherein e and f are numbers corresponding to the degree of polymerization of the resin (= molecular weight of the polymer / molecular weight of the repeating unit), and satisfy the relationship of e: f = 6: 4 (molar ratio of charged base)) .)
BOEDA (Bicyclo [2.2.2] Oct-7-ene-2) was added to a four-necked flask equipped with a glass stirring rod with a fluororesin plate and a condenser tube with a ball (Dean-Stark trap) equipped with a moisture separation trap. , 3,5,6-tetracarboxylic dianhydride, manufactured by Tokyo Chemical Industry Co., Ltd.) 2.98 g (12 mmol), DSDA 2.86 g (8 mmol), DAT 2.44 g (20 mmol), m-cresol 75 g, γ -Valerolactone 0.21g (2.0 mmol), pyridine 0.32g (4.0 mmol), and toluene 10g were added, it was made to react for 5 hours by the bath temperature 180 degreeC / 180 rpm under nitrogen atmosphere, and it was reprecipitated in about 20 times amount methanol. The obtained solid was dried under reduced pressure at 70 ° C. overnight to obtain a polyimide resin. The obtained polyimide resin had a number average molecular weight Mn19,000, a weight average molecular weight Mw30,000, and a polydispersity Mw / Mn = 1.5.

Production Example 4
In this production example, the polyimide resin 4 (the following formula) used in Comparative Example 1 was synthesized.
(Wherein g and h are numbers corresponding to the degree of polymerization of the resin (= molecular weight of polymer / molecular weight of repeating unit), and satisfy the relationship of g: h = 5: 5 (molar ratio of charged base)). .)
BTDA (3,3 ', 4,4'-benzophenone tetracarboxylic) was added to a four-necked flask equipped with a glass stirring rod with a fluororesin plate and a condenser tube with a ball (Dean-Stark trap) equipped with a moisture separation trap. Acid dianhydride, manufactured by Tokyo Chemical Industry Co., Ltd.) 3.29 g (10.2 mmol), DSDA 3.65 g (10.2 mmol), DAT 2.44 g (20 mmol), NMP 84 g, γ-valerolactone 0.21 g (2.0 mmol), pyridine 0.32 g (4.0 mmol) and 10 g of toluene were added, the mixture was reacted at a bath temperature of 180 ° C./180 rpm for 5 hours under a nitrogen atmosphere, and reprecipitated in about 20 times the amount of methanol. The obtained solid was dried under reduced pressure at 70 ° C. for 8 hours to obtain a polyimide resin. The obtained polyimide resin had a number average molecular weight Mn25,000, a weight average molecular weight Mw60,000, and a polydispersity Mw / Mn = 2.4.

Example 1
After adding 1.0 g of polyimide resin 1 to 5.3 g of NMP (N-methylpyrrolidone) and dissolving it, diazonaphthoquinone photosensitizer PC-5 (Toyo Gosei Co., Ltd., 1,2-naphthoquinone-2 as a photoacid generator) -Diazide-5-sulfonic acid-p-cresol ester) 0.3g, 5HIPA (5-hydroxyisophthalic acid, Tokyo Kasei Kogyo Co., Ltd.) 0.1g was added and stirred with a stirrer for about 1 hour at room temperature. (PC-5 30 parts by weight, 5HIPA 10 parts by weight with respect to 100 parts by weight of the resin). This solution is applied onto a 35μm electrolytic copper foil (matte surface) by spin coating (400rpm / 10sec + 600rpm / 30sec), pre-baked with a far-infrared hot air circulation dryer (75 ℃ / 10min), A photosensitive PI coating of about 10 μm was obtained.
This was irradiated with light in the i-line to g-line band by a UV exposure machine (Oak) through a PET photomask. The exposure measured with an illuminometer for the i-line band was 300 mJ / cm ² .
After exposure, 10 g of 2.5 wt% TMAH aqueous solution was used for development by immersion at room temperature and washed with 100 g of ion-exchanged water for 1 minute. As a result, a positive image was obtained. The development time at this time was 9 minutes 49 seconds. The resolution was 15 μm with a line-and-space pattern, and the residual film ratio was 86%. An SEM photograph of this photoresist is shown in FIG. 2A.

Example 2
After adding 1.0 g of polyimide resin 1 to 5.3 g of NMP and dissolving it, 0.2 g of PC-5 and 0.1 g of 5HIPA were added and stirred with a stirrer at room temperature for about 1 hour to prepare a photoresist composition. (PC-5 20 parts by weight, 5HIPA 10 parts by weight with respect to 100 parts by weight of resin). In the same manner as in Example 1, coating, pre-baking, exposure (exposure amount: 300 mJ / cm ² ) and development were performed to obtain a positive image. The development time at this time was 5 minutes and 40 seconds. The resolution was 15 μm in a line and space pattern, and the remaining film rate was 65%. An SEM photograph of this photoresist is shown in FIG. 2B.
Example 3
The photosensitive polyimide coating film obtained by the same operation as in Example 1 was irradiated with light in the i-line to g-line band with a UV exposure machine through a PET photomask. The exposure measured with an illuminometer for the i-line band was 500 mJ / cm ² . Development was performed in the same manner as in Example 1 to obtain a positive image. The development time at this time was 5 minutes and 28 seconds. The resolution was 15 μm with a line-and-space pattern, and the residual film ratio was 86%. An SEM photograph of this photoresist is shown in FIG. 2C.

Example 4
After adding 1.0 g of polyimide resin 2 to 5.3 g of NMP and dissolving it, 0.3 g of PC-5 and 0.1 g of 5HIPA were added and stirred with a stirrer at room temperature for about 1 hour to prepare a photoresist composition. (PC-5 30 parts by weight, 5HIPA 10 parts by weight with respect to 100 parts by weight of resin). Application, pre-baking, and exposure (exposure amount 300 mJ / cm ² ) were performed in the same manner as in Example 1, followed by development by immersion using 10 g of 2.5 wt% TMAH aqueous solution and washing with 100 g of ion-exchanged water for 1 minute. As a result, a positive image was obtained. The development time at this time was 10 minutes and 17 seconds. The resolution was 15 μm in a line and space pattern, and the remaining film rate was 63%. An SEM photograph of this photoresist is shown in FIG. 2D.
Example 5
After adding 1.0 g of polyimide resin 3 to 5.3 g of NMP and dissolving it, 0.3 g of PC-5 and 0.1 g of 5HIPA were added and stirred with a stirrer at room temperature for about 1 hour to prepare a photoresist composition. (PC-5 30 parts by weight, 5HIPA 10 parts by weight with respect to 100 parts by weight of resin). Application, pre-baking, and exposure (exposure amount 300 mJ / cm ² ) were performed in the same manner as in Example 1, followed by development by immersion using 10 g of 2.5 wt% TMAH aqueous solution and washing with 100 g of ion-exchanged water for 1 minute. As a result, a positive image was obtained. The development time at this time was 11 minutes 31 seconds. The resolution was 20 μm in a line and space pattern, and the remaining film rate was 53%. An SEM photograph of this photoresist is shown in FIG. 2E.

Comparative Example 1
After adding 1.0 g of polyimide resin 4 to 5.3 g of NMP and dissolving it, 0.3 g of PC-5 and 0.1 g of 5HIPA were added and stirred with a stirrer at room temperature for about 1 hour to prepare a photoresist composition. (PC-5 30 parts by weight, 5HIPA 10 parts by weight with respect to 100 parts by weight of resin). In the same manner as in Example 1, coating, pre-baking, and exposure (exposure amount 300 mJ / cm ² ) were performed, and then development was performed by immersion using 10 g of 2.5 wt% TMAH aqueous solution. Even after 60 minutes of development, no pattern was formed.

Claims (11)

A photosensitive resin composition for forming a positive photoresist structure containing a polyimide resin and a photoacid generator, wherein the polyimide resin comprises an acid dianhydride and the following formula
(In the formula, R ¹ represents a hydrocarbon group having 6 or less carbon atoms, R ² independently represents a hydrogen atom, a fluorine atom, an alkyl group, an alkoxy group or a fluoroalkyl group, and n is 0. Wherein n is less than or equal to the carbon number of R ¹ ), and the acid dianhydride containing alicyclic acid dianhydride is reacted. Resin composition. The photosensitive resin composition according to claim 1, wherein the acid dianhydride is a mixture of an alicyclic acid dianhydride and an aromatic acid dianhydride. The photosensitive resin composition according to claim 2, wherein a ratio (molar ratio) between the alicyclic acid dianhydride and the aromatic acid dianhydride is 8: 2 to 4: 6. The acid dianhydride comprises acid dianhydride A and acid dianhydride B, and the acid dianhydride A is represented by the following formula:
(In the formula, R ³ represents a tetravalent alicyclic substituent.)
The acid dianhydride B is represented by the following formula
(In the formula, R ⁴ represents a substituent represented by the following formula.)
The photosensitive resin composition of Claim 1 represented by these. The photosensitive resin composition according to claim 4, wherein the ratio of the acid dianhydride A to the acid dianhydride B (molar ratio A: B) is 8: 2 to 4: 6. The photosensitive resin composition as described in any one of Claims 1-5 by which the said diamine compound is represented by the following Formula.
(Wherein R ² and n represent the same as above) The photosensitive resin composition according to claim 1, wherein the photoacid generator is 1,2-naphthoquinone-2-diazide-5-sulfonic acid-p-cresol ester. The photosensitive resin composition according to claim 1, wherein the photosensitive resin composition further contains an alkali dissolution accelerator. The photosensitive resin composition according to claim 8, wherein the alkali dissolution accelerator is selected from the group consisting of alkylsulfonic acid, arylsulfonic acid, alkylcarboxylic acid, and arylcarboxylic acid. A step of providing a photoresist layer containing the photosensitive resin composition according to any one of claims 1 to 9 on a substrate, masking with a desired pattern, irradiating the pattern surface with ultraviolet rays, and A method for forming a positive type photoresist, comprising a developing step of processing a photoresist layer with a developer, wherein the developer is an alkaline aqueous solution. The method of claim 10, wherein the aqueous alkaline solution comprises an aqueous solution of tetra-substituted ammonium hydroxide.