Alkali developing solution and pattern formation method using same

Abstract

According to the present invention, resolution is improved by adding a small amount of an organic solvent in development of a positive photosensitive polyimide resin.　Provided is an alkali developing solution for positive photosensitive polyimides, the alkali developing solution being used when a photosensitive layer formed from a positive photosensitive resin composition including a diazonaphthoquinone-containing polyimide structure is exposed in a pattern form and then developed, wherein (poly)glycerol is contained in an alkaline aqueous solution. The (poly)glycerin content of the alkali aqueous solution is 1-4 mass%.

Description

Alkaline developer and pattern formation method using same

[0001] The present invention relates to an alkaline developer and a pattern forming method using the same.

[0002] Photosensitive polyimide resin compositions that can be developed into positive patterns using an alkaline aqueous solution are widely used in flexible circuit boards as materials for overcoat layers and interlayer insulating films, sealing materials for IC chips, etc. Furthermore, polyimide resins themselves undergo little change in their physical properties in the temperature range of -196°C to 300°C, and are excellent in heat resistance, mechanical properties, electrical insulation, chemical resistance, etc., and are therefore used not only in the flexible circuit boards mentioned above, but also in liquid crystal and organic EL displays, automotive mechanical parts, etc.

[0003] A technique has been disclosed in which a photosensitive layer formed from such a photosensitive polyimide resin composition is exposed to light in a pattern and then developed with an alkaline aqueous solution, so that the exposed areas can be removed with the alkaline aqueous solution, thereby forming a positive pattern of the photosensitive polyimide resin composition (see, for example, Patent Document 1).

[0004] In particular, a technology has been disclosed in which a photosensitive layer formed from a photosensitive polyimide resin composition containing a polyamic acid is exposed to light in a pattern and then developed by adding 49% by weight or less of an organic solvent which is at least one oxygen-containing compound selected from the group consisting of monohydric alcohols, polyhydric alcohols, ketones, and esters to a developer consisting of an aqueous alkaline solution, which is used to develop the photosensitive layer (see, for example, Patent Document 2). This technology further improves the resolution, film peeling margin during development, development time, and the like.

[0005] JP2008-216984A JP11-218932A

[0006] Incidentally, Patent Document 2 shows test results of the resolution, development temperature, development time, and development margin when a developer containing tetramethylammonium hydroxide (TMAH) and tetrabutylammonium hydroxide (TBAH) as alkaline components and 15% by mass of glycerin is used. However, the developer containing 15% by mass of glycerin does not show any significant effects in terms of resolution, development temperature, development time, or development margin compared with the developer containing or not containing other organic solvents.

[0007] Furthermore, Patent Document 2 discloses that a developer containing 15% by mass of isopropyl alcohol is most effective in terms of resolution, development temperature, development time, and development margin. However, because 15% by mass of isopropyl alcohol, an organic solvent, must be added, there is a problem in that it is not possible to reduce costs and environmental impact.

[0008] Therefore, the present invention has been made in view of the above-mentioned problems, and has an object to provide an alkaline developer that improves resolution by adding a small amount of organic solvent in the development of a positive-type photosensitive polyimide resin, and a pattern formation method using the same.

[0009] Mode 1: One or more embodiments of the present invention propose an alkaline developer to be used in patternwise exposure and subsequent development of a photosensitive layer formed from a positive photosensitive resin composition containing (A) one or more resins selected from the group consisting of polyimide, polyimide precursor, polybenzoxazole, polybenzoxazole precursor, and copolymers thereof, and (B) a photosensitizer, the alkaline developer comprising an alkaline aqueous solution containing (poly)glycerin.

[0010] Mode 2: One or more embodiments of the present invention propose an alkaline developer in which the content of the (poly)glycerin in the alkaline aqueous solution is 1% by mass to 4% by mass.

[0011] Mode 3: One or more embodiments of the present invention propose an alkaline developer in which the alkaline aqueous solution is an aqueous solution containing tetramethylammonium hydroxide.

[0012] Mode 4: One or more embodiments of the present invention provide an alkaline developer in which the (poly)glycerin is glycerin and / or diglycerin.

[0013] Mode 5: One or more embodiments of the present invention propose a pattern formation method, which involves developing the exposed photosensitive layer using the alkaline developer according to any one of Modes 1 to 4 to form a pattern of a photosensitive positive-working photosensitive resin composition containing a polyimide structure.

[0014] According to one or more embodiments of the present invention, it is possible to provide a developer that improves resolution and sensitivity by adding a small amount of organic solvent, and a pattern formation method using the same.

[0015] FIG. 1 is a graph showing the dissolution rate of a photosensitive resin composition film with respect to changes in exposure dose.

[0016] <Developer> The alkaline developer according to this embodiment (hereinafter simply referred to as the developer) is an alkaline developer used when patternwise exposing and then developing a photosensitive layer formed from a positive photosensitive resin composition containing (A) one or more resins selected from the group consisting of polyimide, polyimide precursor, polybenzoxazole, polybenzoxazole precursor, and copolymers thereof, and (B) a photosensitizer, and contains (poly)glycerin in an alkaline aqueous solution.

[0017] Examples of the alkaline aqueous solution include organic alkaline compounds such as monoethanolamine, diethanolamine, triethanolamine, methylamine, dimethylamine, ethylamine, diethylamine, triethylamine, cyclohexylamine, tetramethylammonium hydroxide (TMAH), tetraethylammonium hydroxide, and trimethyl-2-hydroxyethylammonium hydroxide (choline), as well as inorganic alkaline compounds such as alkali metal silicates (e.g., lithium, sodium, or potassium), alkali metal hydroxides, alkali metal phosphates, alkali metal carbonates, ammonium phosphates, and ammonium carbonates, with an aqueous solution containing tetramethylammonium hydroxide being more preferred. The organic alkaline compounds can also be used as mixtures.

[0018] In this embodiment, the alkaline aqueous solution is preferably a commonly used 2.38% by mass TMAH aqueous solution.

[0019] (Poly)glycerin means "glycerin" and / or "polyglycerin" having an average degree of polymerization of 2 or more, and preferably "glycerin" and / or "diglycerin", in other words, glycerin having a degree of polymerization of 1 to 2.

[0020] The developer according to this embodiment contains (poly)glycerin in the alkaline aqueous solution described above. The content of (poly)glycerin is preferably 1% by mass to 4% by mass, more preferably 2% by mass to 4% by mass, and particularly preferably 2% by mass.

[0021] <Resolution of Positive Photosensitive Resin Composition> The resolution of a photosensitive resin composition can be evaluated based on the dissolution rate ratio, which is the ratio of the solubility rates of the exposed and unexposed areas of a photosensitive resin composition film, which is a patternwise exposed photosensitive layer. The dissolution rate ratio is the value obtained by dividing the dissolution rate of the exposed area by the dissolution rate of the unexposed area.

[0022] When a photosensitive resin composition film, which is a pattern-wise exposed photosensitive layer, is developed with the developer according to this embodiment, the solubility is suppressed by the contained (poly)glycerin, and the exposure dose is 0 mJ / cm compared to the case of development with a developer containing only an alkaline aqueous solution. ２ The dissolution rate of the unexposed portion is significantly reduced. That is, when the developing solution according to this embodiment is used for development, excessive dissolution of the unexposed portion is suppressed. On the other hand, as the exposure dose increases, the suppression of solubility by the (poly)glycerin contained decreases. For example, at an exposure dose of 500 mJ / cm ２ The dissolution rate of the exposed portion is almost the same when developed with the developer according to this embodiment and when developed with a developer containing only an alkaline aqueous solution.

[0023] Therefore, when development is performed with the developer according to this embodiment, the dissolution rate ratio is higher than when development is performed with a developer containing only an alkaline aqueous solution. Specifically, the dissolution rate ratio in the developer according to this embodiment is 1.06 to 2.31 times higher than the dissolution rate ratio in a developer containing only an alkaline aqueous solution.

[0024] On the other hand, the dissolution rate ratio in a developer containing 1% by mass to 4% by mass of a polyhydric alcohol other than (poly)glycerin in an alkaline aqueous solution is about the same as or 0.68 times lower than the dissolution rate ratio in a developer containing only an alkaline aqueous solution. Examples of polyhydric alcohols other than (poly)glycerin include sorbitol, ethylene glycol, and propylene glycol.

[0025] Therefore, when a photosensitive resin composition film having a patternwise exposed photosensitive layer is developed with the developer according to this embodiment, the dissolution rate ratio is higher than when the film is developed with a developer containing only an alkaline aqueous solution or a developer containing an alkaline aqueous solution containing a polyhydric alcohol other than (poly)glycerin. Furthermore, the dissolution rate ratio contributes to pattern resolution, and the higher the dissolution rate ratio, the higher the pattern resolution. Therefore, when the film is developed with the developer according to this embodiment, the resolution is improved compared to when the film is developed with a developer containing only an alkaline aqueous solution or a developer containing an alkaline aqueous solution containing a polyhydric alcohol other than (poly)glycerin.

[0026] <Sensitivity of Positive Photosensitive Resin Composition> The sensitivity of a photosensitive resin composition can be evaluated based on the optimal exposure dose. In this embodiment, the optimal exposure dose is the exposure dose at which the cross-sectional shape of a pattern formed by developing a photosensitive resin composition film, which is a pattern-wise exposed photosensitive layer, with a developer is closest to the target shape. The pattern is a line-and-space (L / S) pattern of 5 μm / 5 μm, 10 μm / 10 μm, 15 μm / 15 μm, or 20 μm / 20 μm.

[0027] When developed with the developer according to this embodiment, the optimum exposure dose for any of the above-mentioned L / S patterns is 600 mJ / cm ２ On the other hand, when developed using only an alkaline aqueous solution as a developer, the optimum exposure dose for any of the above-mentioned L / S patterns is 650 mJ / cm ２ is.

[0028] Therefore, when a photosensitive resin composition film, which is a patternwise exposed photosensitive layer, is developed with the developer according to this embodiment, the optimal exposure dose is lowered compared to when the film is developed with a developer containing only an alkaline aqueous solution. This is because the suppression of solubility by the (poly)glycerin contained in the developer according to this embodiment increases the dissolution rate ratio compared to when the film is developed with a developer containing only an alkaline aqueous solution, thereby lowering the optimal exposure dose. Furthermore, when a photosensitive resin composition film, which is a patternwise exposed photosensitive layer, is developed with the developer according to this embodiment, the optimal exposure dose is lowered, and therefore the sensitivity of the photosensitive resin composition is improved.

[0029] <Positive-type photosensitive resin composition> The photosensitive resin composition in which the alkaline developer of the present invention can be used contains (A) one or more resins selected from the group consisting of polyimide, polyimide precursor, polybenzoxazole, polybenzoxazole precursor, and copolymers thereof (hereinafter, may be referred to as resin (A)). The photosensitive resin composition may contain these resins alone or in combination. The polyimide, polyimide precursor, polybenzoxazole, and polybenzoxazole precursor will now be described.

[0030] The polyimide is not particularly limited as long as it has an imide ring. The polyimide precursor is not particularly limited as long as it has a structure that becomes a polyimide having an imide ring by dehydration ring closure, and may contain a polyamic acid, a polyamic acid ester, or the like.

[0031] The polybenzoxazole is not particularly limited as long as it has an oxazole ring. The polybenzoxazole precursor is not particularly limited as long as it has a structure that becomes a polybenzoxazole having a benzoxazole ring by dehydration ring closure, and may contain a polyhydroxyamide or the like.

[0032] Examples of the structural unit of each resin include a structural unit represented by the following formula (1) for polyimide, a structural unit represented by the following formula (2) for polyimide precursors and polybenzoxazole precursors, and a structural unit represented by the following formula (3) for polybenzoxazole. Two or more of these may be contained, or a resin may be contained in which the structural unit represented by general formula (1), the structural unit represented by general formula (2), and the structural unit represented by general formula (3) are copolymerized.

[0033] In general formula (1), V represents a tetravalent to decavalent organic group having 4 to 40 carbon atoms, W represents a divalent to octavalent organic group having 4 to 40 carbon atoms, and a and b each represent an integer of 0 to 6. １ and R ２ represents a group selected from the group consisting of a hydroxyl group, a carboxyl group, a sulfonic acid group, and a thiol group, and a plurality of R １ and R ２ may be the same or different.

[0034] In the general formula (2), X and Y each independently represent a divalent to octavalent organic group having 4 to 40 carbon atoms. ３ and R ４ each independently represents a hydrogen atom or a monovalent organic group having 1 to 20 carbon atoms, c and d each represent an integer of 0 to 4, and e and f each represent an integer of 0 to 2.

[0035] In general formula (3), T and U each independently represent a divalent to octavalent organic group having 4 to 40 carbon atoms. To impart alkali solubility to the (A) resin, it is preferable that a+b>0 in general formula (1). It is also preferable that c+d+e+f>0 in general formula (2).

[0036] In the case of a polyimide precursor, it is preferable that X and Y in general formula (2) have an aromatic group. Furthermore, X in general formula (2) has an aromatic group, e>2, and a carboxyl group or a carboxy ester group at the ortho position of the aromatic amide group, resulting in a structure that forms an imide ring by dehydration ring closure. Furthermore, in the case of a polybenzoxazole precursor, X in general formula (2) has an aromatic group, d>0, and a hydroxyl group at the ortho position of the aromatic amide group, resulting in a structure that forms a benzoxazole ring by dehydration ring closure.

[0037] In the (A) resin, the repeating number n of the structural unit represented by general formula (1), general formula (2), or general formula (3) is preferably 5 to 100,000, more preferably 10 to 100,000. Furthermore, the (A) resin may contain other structural units in addition to the structural units represented by general formula (1), general formula (2), or general formula (3). Examples of other structural units include, but are not limited to, cardo structures and siloxane structures. In this case, it is preferable that the structural units represented by general formula (1) or general formula (2) are the main structural units. Here, the term "main structural units" refers to structural units represented by general formula (1), general formula (2), or general formula (3) that account for 50 mol% or more of the total number of structural units, more preferably 70 mol% or more.

[0038] In the above general formula (1), V-(R １ )a, in the above general formula (2), (OH)c-X-(COOR ３) e and T in the above general formula (3) represent an acid residue. V is a tetravalent to decavalent organic group having 4 to 40 carbon atoms, and among these, an organic group having 4 to 40 carbon atoms and containing an aromatic ring or a cyclic aliphatic group is preferred. X and T are divalent to octavalent organic groups having 4 to 40 carbon atoms, and among these, an organic group having 4 to 40 carbon atoms and containing an aromatic ring or an aliphatic group is preferred.

[0039] Examples of acid components constituting the acid residue include dicarboxylic acids such as terephthalic acid, isophthalic acid, diphenyl ether dicarboxylic acid, bis(carboxyphenyl)hexafluoropropane, biphenyl dicarboxylic acid, benzophenone dicarboxylic acid, triphenyl dicarboxylic acid, suberic acid, dodecafluorosuberic acid, azelaic acid, sebacic acid, hexadecafluorosebacic acid, 1,9-nonanedioic acid, dodecanedioic acid, tridecanedioic acid, tetradecanedioic acid, pentadecanedioic acid, hexadecanedioic acid, heptadecanedioic acid, octadecanedioic acid, and nonadecanedioic acid; Examples of tricarboxylic acids include trimellitic acid, trimesic acid, diphenyl ether tricarboxylic acid, and biphenyl tricarboxylic acid. Examples of tetracarboxylic acids include pyromellitic acid, 3,3',4,4'-biphenyltetracarboxylic acid, 2,3,3',4'-biphenyltetracarboxylic acid, and 2,2',3,3'-biphenyltetracarboxylic acid. acid, 3,3',4,4'-diphenyl ether tetracarboxylic acid, 3,3',4,4'-benzophenone tetracarboxylic acid, 2,2',3,3'-benzophenone tetracarboxylic acid, 2,2-bis(3,4-dicarboxyphenyl)propane, 2,2-bis(2,3-dicarboxyphenyl)propane, 1,1-bis(3,4-dicarboxyphenyl)ethane, 1,1-bis(2,3-dicarboxyphenyl)ethane, bis(3,4-dicarboxyphenyl)methane, bis(2,3-dicarboxyphenyl)methane, bis(3,4-dicarboxyphenyl) phenyl) ether, 1,2,5,6-naphthalenetetracarboxylic acid, 9,9-bis(3,4-dicarboxyphenyl)fluorene, 9,9-bis{4-(3,4-dicarboxyphenoxy)phenyl}fluorene, 2,3,6,7-naphthalenetetracarboxylic acid, 2,3,6,7-naphthalenetetracarboxylic acid, 2,3,5,6-pyridinetetracarboxylic acid, 3,4,9,10-perylenetetracarboxylic acid, 2,2-bis(3,4-dicarboxyphenyl)hexafluoropropane, butanetetracarboxylic acid, cyclobutanetetracarboxylic acid, 1,2,3,4-cyclopentanetetracarboxylic acid, etc., but are not limited to these. Two or more of these may be used.

[0040] W-(R ２ ) b, (OH)d-Y-(COOR) in the above general formula (2) ４ ) f and U in the general formula (3) above represent a residue of a diamine. W, Y, and U are divalent to octavalent organic groups having 4 to 40 carbon atoms, and among these, organic groups having 4 to 40 carbon atoms and containing an aromatic ring or a cycloaliphatic group are preferred.

[0041] Specific examples of diamines constituting the diamine residue include hydroxyl group-containing diamines such as bis(3-amino-4-hydroxyphenyl)hexafluoropropane, bis(3-amino-4-hydroxyphenyl)sulfone, bis(3-amino-4-hydroxyphenyl)propane, bis(3-amino-4-hydroxyphenyl)methylene, bis(3-amino-4-hydroxyphenyl)ether, bis(3-amino-4-hydroxy)biphenyl, and bis(3-amino-4-hydroxyphenyl)fluorene; 3-sulfonic acid-4,4'-diaminodiphenyl; sulfonic acid-containing diamines such as dimercaptophenylenediamine, thiol group-containing diamines such as dimercaptophenylenediamine, 3,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl ether, 3,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylmethane, 3,4'-diaminodiphenyl sulfone, 4,4'-diaminodiphenyl sulfone, 3,4'-diaminodiphenyl sulfide, 4,4'-diaminodiphenyl sulfide, 1,4-bis(4-aminophenoxy)benzene, benzine, m-phenylenediamine, p-phenylene diamine, 1,5-naphthalenediamine, 2,6-naphthalenediamine, bis(4-aminophenoxyphenyl)sulfone, bis(3-aminophenoxyphenyl)sulfone, bis(4-aminophenoxy)biphenyl, bis{4-(4-aminophenoxy)phenyl}ether, 1,4-bis(4-aminophenoxy)benzene, 2,2'-dimethyl-4,4'-diaminobiphenyl, 2,2'-diethyl-4,4'-diaminobiphenyl, 3,3'-dimethyl-4,4'-diaminobiphenyl, 3,3'-diethyl-4,4'-diaminobiphenyl, Aromatic diamines such as 2,2',3,3'-tetramethyl-4,4'-diaminobiphenyl, 3,3',4,4'-tetramethyl-4,4'-diaminobiphenyl, and 2,2'-bis(trifluoromethyl)-4,4'-diaminobiphenyl, 1,3-bis(3-aminopropyl)-1,1,3,3-tetramethyldisiloxane, 1,3-bis(p-aminophenyl)-1,1,3,3-tetramethyldisiloxane, 1,3-bis(p-aminophenethyl)-1,1,3,3-tetramethyldisiloxane, and 1,7-bis(p-aminophenyl)-1,1,3,Examples of suitable diamines include silicone diamines such as 3,5,5,7,7-octamethyltetrasiloxane, alicyclic diamines such as cyclohexyldiamine and methylenebiscyclohexylamine, and diamines having the structures shown below. Two or more of these may be used.

[0042] In the formula, R ５ represents a single bond, an oxygen atom, or a C(CF ３ )2, or C(CH ３ ) 2. R ６ and R ７ each independently represents a hydrogen atom or a hydroxyl group.

[0043] The photosensitive resin composition for which the alkaline developer of this embodiment can be used contains a (B) photosensitizer (hereinafter, sometimes referred to as component (B)). The inclusion of component (B) imparts photosensitivity to the resin composition, making it possible to form a fine opening pattern. The component (B) is a compound whose chemical structure changes in response to ultraviolet light, and examples of the component (B) include a photoacid generator, a photobase generator, and a photopolymerization initiator.

[0044] When a photoacid generator is used as component (B), acid is generated in the irradiated portions of the photosensitive resin composition, increasing the solubility of the irradiated portions in an alkaline developer, thereby obtaining a positive-tone pattern in which the irradiated portions dissolve. From the viewpoint of fine processability, it is preferable that the resin composition containing resin (A) and component (B) has positive photosensitivity. Among the above-mentioned components (B), a photoacid generator is preferred from the viewpoint of high sensitivity and fine processability.

[0045] Examples of the photoacid generator include quinone diazide compounds, sulfonium salts, phosphonium salts, diazonium salts, and iodonium salts. Furthermore, a sensitizer may be included as needed. As the quinone diazide compound, a compound in which a sulfonic acid of naphthoquinone diazide is bonded to a compound having a phenolic hydroxyl group via an ester bond is preferred.

[0046] The compound having a phenolic hydroxyl group used here may be a known compound, and preferred examples include those into which 4-naphthoquinone diazide sulfonic acid or 5-naphthoquinone diazide sulfonic acid has been introduced via an ester bond, but other compounds may also be used. It is also preferred that 50 mol % or more of the total functional groups of the compound having a phenolic hydroxyl group be substituted with quinone diazide.

[0047] By using a quinone diazide compound substituted by 50 mol% or more, the affinity of the quinone diazide compound for alkaline aqueous solutions is reduced. As a result, the solubility of the unexposed portions of the resin composition in alkaline aqueous solutions is significantly reduced. Furthermore, the quinone diazide sulfonyl group is converted to an indene carboxylic acid by exposure, resulting in a high dissolution rate of the exposed portions of the photosensitive resin composition in alkaline aqueous solutions. That is, as a result, the dissolution rate ratio between the exposed and unexposed portions of the composition is increased, allowing for the production of patterns with high resolution.

[0048] By containing such a quinone diazide compound, it is possible to obtain a resin composition having positive photosensitivity that is sensitive to the i-line (365 nm), h-line (405 nm), and g-line (436 nm) of a general mercury lamp, or to a broad band including these. Furthermore, the component (B) may be contained alone or in combination of two or more types, and a highly sensitive resin composition may be obtained.

[0049] Examples of quinone diazides include a 5-naphthoquinone diazide sulfonyl group, a 4-naphthoquinone diazide sulfonyl group, and those containing a 4-naphthoquinone diazide sulfonyl group and a 5-naphthoquinone diazide sulfonyl group in the same molecule.

[0050] Examples of naphthoquinone diazide sulfonyl ester compounds include 5-naphthoquinone diazide sulfonyl ester compounds (B-1) and 4-naphthoquinone diazide sulfonyl ester compounds (B-2). In the present embodiment, it is preferable to include compound (B-1).

[0051] The absorption of the (B-1) compound extends to the g-line region of a mercury lamp, making it suitable for g-line exposure and full-wavelength exposure. Furthermore, during curing, the (B-1) compound reacts with the (A) resin, etc., to form a crosslinked structure, improving chemical resistance. Furthermore, since it exhibits less coloration after heat treatment than the (B-2) compound, it is also preferred from the viewpoint of light transmittance after heat treatment. The content of the (B-1) compound is preferably 55% by mass or more and 100% by mass or less of the total amount of photosensitizer (the (B-1) compound + the (B-2) compound). By achieving this content ratio, a cured film with high light transmittance can be obtained.

[0052] The quinone diazide compound can be synthesized by a known method through an esterification reaction between a compound having a phenolic hydroxyl group and a quinone diazide sulfonic acid compound. The use of the quinone diazide compound further improves resolution, sensitivity, and film retention.

[0053] The molecular weight of component (B) is preferably 300 or more, more preferably 350 or more, and preferably 3,000 or less, more preferably 1,500 or less, from the viewpoint of the heat resistance, mechanical properties, and adhesiveness of the film obtained by heat treatment. Of the components (B), sulfonium salts, phosphonium salts, and diazonium salts are preferred because they appropriately stabilize the acid component generated by exposure. Of these, sulfonium salts are preferred.

[0054] The content of the (B) component is preferably 0.1 parts by mass or more and 100 parts by mass or less relative to 100 parts by mass of the (A) resin. If the content of the (B) component is 0.1 parts by mass or more and 100 parts by mass or less, photosensitivity can be imparted while maintaining the heat resistance, chemical resistance, and mechanical properties of the film after heat treatment. When the (B) component contains a quinone diazide compound, the content of the (B) component is more preferably 1 part by mass or more, and even more preferably 3 parts by mass or more, relative to 100 parts by mass of the (A) resin. Also, 100 parts by mass or less is more preferable, and 80 parts by mass or less is even more preferable. If the content is 1 part by mass or more and 100 parts by mass or less, photosensitivity can be imparted while maintaining the heat resistance, chemical resistance, and mechanical properties of the film after heat treatment.

[0055] The present invention will be described in detail below with reference to examples, but the present invention is not limited to the following description.

[0056] Synthesis Example 1: Synthesis of Hydroxyl Group-Containing Diamine Compound 18.3 g (0.05 mol) of 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane (manufactured by Central Glass Co., Ltd., hereinafter referred to as BAHF) was dissolved in 100 mL of acetone and 17.4 g (0.3 mol) of propylene oxide (manufactured by Tokyo Chemical Industry Co., Ltd.), and the solution was cooled to −15°C. To this solution, a solution of 20.4 g (0.11 mol) of 3-nitrobenzoyl chloride (manufactured by Tokyo Chemical Industry Co., Ltd.) dissolved in 100 mL of acetone was added dropwise. After completion of the dropwise addition, the mixture was stirred at −15°C for 4 hours and then returned to room temperature. The precipitated white solid was filtered and dried in vacuo at 50°C. 30 g of the obtained white solid was placed in a 300 mL stainless steel autoclave and dispersed in 250 mL of methyl cellosolve, and 2 g of 5% palladium-carbon (manufactured by Wako Pure Chemical Industries, Ltd.) was added. Hydrogen was introduced into the flask using a balloon, and the reduction reaction was carried out at room temperature. After about two hours, the reaction was terminated when it was confirmed that the balloon was no longer deflating. After the reaction was completed, the palladium compound catalyst was removed by filtration, and the mixture was concentrated using a rotary evaporator to obtain a hydroxyl group-containing diamine compound represented by the following formula:

[0057] Synthesis Example 2: Synthesis of Polyimide (a-1) Under a dry nitrogen stream, 29.3 g (0.08 mol) of BAHF, 1.2 g (0.005 mol) of 1,3-bis(3-aminopropyl)tetramethyldisiloxane (hereinafter referred to as SiDA), and 3.3 g (0.03 mol) of 3-aminophenol as an end-capping agent were dissolved in 80 g of N-methyl-2-pyrrolidone (hereinafter referred to as NMP). To this solution, 31.2 g (0.1 mol) of 4,4'-oxydiphthalic anhydride (hereinafter referred to as ODPA) was added together with 20 g of NMP, and the mixture was reacted at 60°C for 1 hour, followed by stirring at 180°C for 4 hours. After stirring, the solution was poured into 3 L of water to obtain a white precipitate. This precipitate was collected by filtration, washed three times with water, and then dried in a vacuum dryer at 80°C for 20 hours to obtain a powder of polyimide (a-1).

[0058] Synthesis Example 3: Synthesis of Polyimide Precursor (a-2) Under a dry nitrogen stream, 51.9 g (0.086 mol) of the hydroxyl group-containing diamine obtained in Synthesis Example 1 and 1.0 g (0.004 mol) of SiDA were dissolved in 200 g of NMP. 31.0 g (0.10 mol) of ODPA was added thereto, and the mixture was stirred at 40°C for 2 hours. Then, 1.1 g (0.01 mol) of 3-aminophenol (manufactured by Tokyo Chemical Industry Co., Ltd.) was added as an end-capping agent along with 10 g of NMP, and the mixture was allowed to react at 40°C for 1 hour. Subsequently, a solution prepared by diluting 7.1 g (0.06 mol) of dimethylformamide dimethyl acetal (manufactured by Mitsubishi Rayon Co., Ltd., hereinafter referred to as DFA) with 5 g of NMP was added dropwise. After the dropwise addition, stirring was continued for 2 hours at 40°C. After stirring was completed, the solution was poured into 2 L of water, and the polymer solid precipitate was collected by filtration. The solid was then washed three times with 2 L of water, and the collected polymer solid was dried in a vacuum dryer at 50° C. for 72 hours to obtain a polyimide precursor (a-2).

[0059] Synthesis Example 4: Synthesis of Polybenzoxazole Precursor (a-3) Under a dry nitrogen stream, 34.8 g (0.1 mol) of BAHF and 1.2 g (0.01 mol) of SiDA were dissolved in 200 g of NMP. Subsequently, while maintaining the temperature at 0 to 5°C, 23.6 g (0.08 mol) of 4,4'-oxybenzoyl chloride was added together with 50 g of NMP, and the mixture was allowed to react for 1 hour. The temperature was then returned to room temperature, and 6.6 g (0.04 mol) of 5-norbornene-2,3-dicarboxylic anhydride was added together with 10 g of NMP, and the mixture was allowed to react for an additional 1 hour. After completion of the reaction, the solution was poured into 3.0 L of water to obtain a white precipitate. The precipitate was collected by filtration, washed three times with water, and then dried in a forced-air dryer at 50°C for 3 days, yielding a powder of polybenzoxazole precursor (a-3).

[0060] Synthesis Example 5: Synthesis of Photosensitizer (Quinone Diazide Compound) (b-1) Under a dry nitrogen stream, 21.2 g (0.05 mol) of 4,4'-[1-[4-[1-(4-hydroxyphenyl-1)-1-methylethyl]phenyl]ethylidene]bisphenol (manufactured by Honshu Chemical Industry Co., Ltd., hereinafter referred to as TrisP-PA) and 26.8 g (0.10 mol) of 5-naphthoquinone diazide sulfonic acid chloride (manufactured by Toyo Gosei Co., Ltd., NAC-5) were dissolved in 450 g of γ-butyrolactone (hereinafter referred to as GBL) at room temperature. 12.7 g of triethylamine mixed with 50 g of GBL was added dropwise to the solution so that the temperature in the system did not exceed 35°C. After the dropwise addition, the mixture was stirred at 40°C for 2 hours. The triethylamine salt was filtered off, and the filtrate was poured into water. The precipitate was then collected by filtration and washed with 1 L of 1% aqueous hydrochloric acid, followed by two more washes with 2 L of water. The precipitate was dried in a vacuum dryer to obtain a quinone diazide compound (b-1) represented by the following formula:

[0061] Preparation Example 1 Preparation of Positive Photosensitive Resin Composition Under yellow light, 10 g of polyimide (a-1) and 2.0 g of photosensitizer (b-1) were dissolved in 14.5 g of GBL, and 0.3 g of a 1 mass % GBL solution of "BYK-333 (trade name)" (manufactured by BYK Japan KK), a silicone surfactant, was added and stirred to obtain a varnish (V1).

[0062] Preparation Example 2: Preparation of Positive Photosensitive Resin Composition Under yellow light, 10 g of polyimide precursor (a-2) and 2.0 g of photosensitizer (b-1) were dissolved in 14.5 g of GBL, and 0.3 g of a 1 mass % GBL solution of "BYK-333 (trade name)" (manufactured by BYK Japan KK), a silicone surfactant, was added and stirred to obtain a varnish (V2).

[0063] Preparation Example 3: Preparation of Positive Photosensitive Resin Composition Under yellow light, 10 g of polybenzoxazole precursor (a-3) and 2.0 g of photosensitizer (b-1) were dissolved in 14.5 g of GBL, and 0.3 g of a 1 mass % GBL solution of "BYK-333 (trade name)" (manufactured by BYK Japan KK), a silicone surfactant, was added and stirred to obtain a varnish (V3).

[0064] <Developer Preparation> The developer used in this example was prepared by dissolving tetramethylammonium hydroxide (TMAH) as an organic alkaline component and several types of water-soluble organic solvents in purified water (ion-exchanged water IEW) and mixing them. The several types of water-soluble organic solvents were glycerin (GLY), diglycerin (DIG), sorbitol (SOR), ethylene glycol (EG), and propylene glycol (PG). The method for dissolving and mixing TMAH and several types of water-soluble organic solvents in purified water is not particularly limited.

[0065] The developers used in Examples 1 to 6 and Comparative Examples 1 to 10 were prepared according to the ingredients listed in Table 1.

[0066] <Evaluation of Dissolution Rate of Positive Photosensitive Resin Composition Film> The film thickness of the photosensitive resin composition after development with the developer described in Examples 1 to 6 and Comparative Examples 1 to 10 was measured using a stylus-type step profiler to evaluate the solubility of the photosensitive resin composition.

[0067] The varnish V1 obtained in Preparation Example 1 was applied by a spin coater and then prebaked (PAB) for 3 minutes to obtain a photosensitive resin composition film having a thickness of 12 μm. The film was exposed to light at an exposure dose of 0 to 500 mJ / cm using a mask aligner (light source: Mercury Lump Power supply, alignment device: M-1S, manufactured by MIKASA) through an i-line bandpass filter. ２ The exposure was carried out so that

[0068] The photosensitive resin composition film after exposure was developed by immersing it in the developer described in Examples 1 to 6 and Comparative Examples 1 to 10. The film thickness of the developed photosensitive resin composition film was measured with a stylus-type step gauge (Dectak XT-E, manufactured by BURKER), and the amount of film thickness reduction (nm) was divided by the development time (sec) to evaluate the dissolution rate (nm / sec) of the photosensitive resin composition film.

[0069] Figure 1 shows a graph of the dissolution rate of a photosensitive resin composition film. In this graph, the solid line plotted with black circles indicates the dissolution rate when the developer described in Example 2 was used, and the dotted line plotted with black squares indicates the dissolution rate of a photosensitive resin composition film when the developer described in Comparative Example 1 was used. From Figure 1, it can be seen that the dissolution rate is slower with the developer described in Example 2 than with the developer described in Example 1. On the other hand, the change in dissolution rate is observed when the exposure dose is 0 to 500 mJ / cm. ２ As the exposure dose increases, the dissolution rate improves for both the developer described in Example 2 and the developer described in Comparative Example 1. However, the solid line for the developer described in Example 2 has a steeper slope, and it is clear that the dissolution rate changes significantly as the exposure dose increases. Therefore, the dissolution rate ratio between the exposed and unexposed areas is significantly higher for exposure doses of 0 to 500 mJ / cm. ２ , particularly 10 to 500 mJ / cm ２ It can be seen that the difference is larger than that in Comparative Example 1.

[0070] In the development process, the value obtained by dividing the dissolution rate of the photosensitive resin composition film in the exposed area by the dissolution rate of the photosensitive resin composition film in the unexposed area is called the dissolution rate ratio, and is used as an index of the resolution of the photosensitive resin composition. The resolution of the photosensitive resin composition increases as the dissolution rate of the exposed area increases and the dissolution rate of the unexposed area decreases, i.e., as the dissolution rate ratio increases.

[0071] For the developers described in Examples 1 to 6 and Comparative Examples 1 to 10, the dissolution rate ratio (dissolution rate of exposed area / dissolution rate of unexposed area) was calculated from the dissolution rates of the exposed area and unexposed area measured by the method described above. Table 1 shows this ratio.

[0072]

[0073] As shown in Table 1, the dissolution rate ratios of all of Examples 1 to 6 were 0.5 or more higher than the value of 9.1 in Comparative Example 1. This shows that when the alkaline developer contains glycerin and / or diglycerin, i.e., (poly)glycerin, the dissolution rate ratio is improved and the resolution of the photosensitive resin composition is improved.

[0074] <Evaluation of Sensitivity of Positive Photosensitive Resin Composition> A photosensitive resin composition film was exposed to an exposure dose of 50 mJ / cm２ 500-750 mJ / cm ２ After exposure within the range of 1000 nm, the photosensitive resin composition was developed with the developer described in Example 2 and Comparative Example 1, and the sensitivity of the photosensitive resin composition was evaluated from the cross-sectional shape of the photosensitive resin composition.

[0075] Specifically, a silicon wafer was first coated with an i-line photosensitive positive polyimide resist (LT-Series, manufactured by Toray Industries, Inc.) using a coater developer (Clean Track ACT-8, manufactured by TEL), and then subjected to PAB for 3 minutes to obtain a 12 μm-thick photosensitive resin composition film. An i-line stepper (NSR-2005iC9, manufactured by Nikon) was used, and the exposure dose was 50 mJ / cm. ２ 500-750 mJ / cm ２ The photosensitive resin composition was exposed to light within the range of .

[0076] After the exposure, the wafer was subjected to puddle development using a small developing apparatus (AD-1200, manufactured by MIKASA) to develop the photosensitive resin composition film using the developer described in Example 2 and Comparative Example 1. An image of the cross section of the obtained pattern was obtained using a scanning electron microscope (FE-SEM S-4800, manufactured by HITACHI High Tech), and the shape of the developed pattern was measured.

[0077] The pattern shape was a line and space (L / S) pattern, and the cross-sectional shape of the part with a 1:1 line width was observed. The optimal exposure amount was the exposure amount when the space part exceeded the designed line width and became the shape closest to the designed line width. Table 2 shows the optimal exposure amounts for L / S patterns of 5 μm / 5 μm, 10 μm / 10 μm, 15 μm / 15 μm, and 20 μm / 20 μm.

[0078]

[0079] As shown in Table 2, for all L / S patterns, the optimum exposure dose was smaller when developed with the developer of Example 2 than when developed with the developer of Comparative Example 1. Since the required exposure dose decreases as the sensitivity of the photosensitive resin composition increases, it can be seen that the sensitivity of the photosensitive resin composition is higher when developed with the developer of Example 2 than when developed with the developer of Comparative Example 1. This shows that when the alkaline developer contains glycerin and / or diglycerin, i.e., (poly)glycerin, the sensitivity of the photosensitive resin composition increases, thereby enabling energy savings and time reduction in the lithography process.

[0080] Examples 7 and 8 Using V2 and V3 obtained in Preparation Examples 2 and 3, the dissolution rate was evaluated in the same manner as in Example 1. The dissolution rate ratio was 14.0 for Example 7 and 12.5 for Example 8.

[0081] Although the embodiment of the present invention has been described in detail, the present invention is not limited to this embodiment, and includes modifications within the scope of the present invention that do not depart from the gist of the present invention.

Claims

1. An alkaline developer used in developing a photosensitive layer formed from a positive photosensitive resin composition, the photosensitive layer comprising (A) one or more resins selected from the group consisting of polyimide, polyimide precursor, polybenzoxazole, polybenzoxazole precursor, and copolymers thereof, and (B) a photosensitizer, the alkaline developer comprising an alkaline aqueous solution containing (poly)glycerin.

2. The alkaline developer according to claim 1, wherein the content of the (poly)glycerin in the alkaline aqueous solution is 1% by mass to 4% by mass.

3. The alkaline developer according to claim 1, wherein the alkaline aqueous solution is an aqueous solution containing tetramethylammonium hydroxide.

4. The alkaline developer according to claim 1, wherein the (poly)glycerin is glycerin and / or diglycerin.

5. A pattern forming method, comprising developing the exposed photosensitive layer with the alkaline developer according to any one of claims 1 to 4 to form a pattern of a positive-type photosensitive resin composition containing a polyimide structure.

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