Photosensitive resin composition

Abstract

To provide a photosensitive resin composition exhibiting favorable rectangularity (taper characteristic) of a pattern and in which a content of N-methyl-2-pyrrolidone, which imposes a high burden on the environment, is reduced.SOLUTION: A photosensitive resin composition comprises an alkali-soluble resin and an organic solvent, wherein the alkali-soluble resin contains at least one selected from polyimide, polybenzoxazole, and their precursors, and wherein the organic solvent includes a first solvent, the first solvent being selected from dimethyl sulfoxide, N,N-dimethylpropionamide, and propylene glycol monomethyl ether.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a photosensitive resin composition. [Background technology]

[0002] Polyamide resins having excellent heat resistance, electrical properties, and mechanical properties have been used as surface protective films and interlayer insulating films for semiconductor elements. Such polyamide resins are dissolved in organic solvents, mixed with a photosensitizer, and provided as varnish-like photosensitive resin compositions for use in pattern formation processes for semiconductor element protective films and interlayer insulating films.

[0003] In this regard, known technologies are disclosed in Patent Documents 1 and 2. Patent Document 1 discloses a technology for obtaining a photosensitive resin composition containing a polyimide precursor or a polybenzoxazole precursor and a polar solvent having a specific structure, in which the content of N-methyl-2-pyrrolidone in the photosensitive resin composition is adjusted to 0.1% by mass or less, thereby preventing gelation over time and improving sensitivity and mechanical properties.

[0004] Cited Document 2 proposes a technology for obtaining a photosensitive resin composition containing an alkali-soluble resin such as polyimide and an organic solvent, using a combination of organic solvents having a boiling point of 210 to 260°C at atmospheric pressure, such as N-methyl-2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone, and 3-methoxy-N,N-dimethylpropionamide, organic solvents having a boiling point of 140 to 210°C at atmospheric pressure, such as ethyl lactate and butyl lactate, and organic solvents having a boiling point of 100 to 140°C at atmospheric pressure, such as ethylene glycol monomethyl ether and propylene glycol monomethyl ether, thereby obtaining a resin composition with improved pattern processing accuracy. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] International Publication No. 2014 / 115233 [Patent Document 2] International Publication No. 2016 / 167038 Summary of the Invention [Problem to be solved by the invention]

[0006] In Patent Document 1, from the viewpoint of reducing the burden on the environment, an appropriate solvent and the like are selected to reduce the content of N-methyl-2-pyrrolidone in the resin composition. However, in the stage of producing the resin described in Synthesis Example 1 of Patent Document 1, N-methyl-2-pyrrolidone is used as a so-called synthesis solvent, and after the reaction, an operation of washing the organic layer to reduce the amount of N-methyl-2-pyrrolidone is performed. Such an operation complicates the process, and there is a concern that N-methyl-2-pyrrolidone may remain when the process is scaled up.

[0007] Patent Document 2 describes an embodiment in which a solvent other than N-methyl-2-pyrrolidone is used as the organic solvent in the resin composition. However, changing the organic solvent in the resin composition can cause changes in patterning characteristics, resulting in poor pattern accuracy and poor pattern quality (rectangularity) in some cases.

[0008] In view of the above circumstances, the present invention has been made, and an object of the present invention is to provide a photosensitive resin composition that reduces the content of N-methyl-2-pyrrolidone, which has a high environmental impact, and that provides a pattern with good rectangularity (taperability). [Means for solving the problem]

[0009] According to the present invention, there is provided the following photosensitive resin composition. [1] an alkali-soluble resin, and an organic solvent; the alkali-soluble resin contains at least one selected from polyimide, polybenzoxazole, and precursors thereof; the organic solvent comprises a first solvent, The first solvent is at least one selected from dimethyl sulfoxide, N,N-dimethylpropionamide, and propylene glycol monomethyl ether; Photosensitive resin composition. [2] The photosensitive resin composition according to item [1], the organic solvent further comprises a second solvent; The photosensitive resin composition, wherein the second solvent is at least one selected from the group consisting of γ-butyl lactone and N-methyl-2-pyrrolidone. [3] The photosensitive resin composition according to item [2], the organic solvent includes the first solvent and the second solvent, The photosensitive resin composition, wherein the first solvent is contained in an amount of 10% by mass or more and 80% by mass or less based on the total amount of the organic solvent. [4] The photosensitive resin composition according to item [2] or [3], the organic solvent includes N-methyl-2-pyrrolidone; A photosensitive resin composition, wherein the amount of N-methyl-2-pyrrolidone is 50% by mass or less based on the total amount of the photosensitive resin composition. [5] The photosensitive resin composition according to item [1], The photosensitive resin composition, wherein the organic solvent consists solely of the first solvent. [6] The photosensitive resin composition according to any one of items [2] to [4], The photosensitive resin composition, wherein the organic solvent comprises the first solvent and the second solvent. [7] The photosensitive resin composition according to any one of items [1] to [6], A photosensitive resin composition having a taper angle of 40° or more and 60° or less when measured under the following condition 1: (Condition 1) Pattern formation conditions: The photosensitive resin composition is applied to an 8-inch silicon wafer using a spin coater, and then pre-baked on a hot plate at 120°C for 4 minutes to obtain a coating film with a thickness of approximately 9.8 μm. The coating film is then heat-treated in a nitrogen atmosphere at 300°C for 60 minutes. Next, the heat-treated coating film is irradiated with 500 mJ / cm using an i-line stepper (Nikon NSR-4425i) through a mask (manufactured by Toppan Printing Co., Ltd.) (on which a line-shaped cutout pattern of 10 to 100 μm is drawn). 2 The photosensitive resin composition is then irradiated with an exposure dose of 10 ... Taper angle measurement conditions: Check the cross section of the 40 μm line-shaped cutout pattern in the pattern. Measure the angle drawn from the contact point on the wafer to the tangent of the arc-shaped remaining pattern portion, and use this angle as the taper angle (°). [8] The photosensitive resin composition according to any one of items [1] to [7], A photosensitive resin composition having a 5% weight loss temperature of 370°C or higher and 410°C or lower when measured under the following condition 2: (Condition 2) Curing conditions: The photosensitive resin composition is heated in a nitrogen atmosphere at 300° C. for 60 minutes to obtain a cured product. 5% weight loss temperature measurement conditions: 10 mg of the cured product was heated from 25°C to 600°C at a heating rate of 10°C / min in an air atmosphere. The temperature at which a 5% weight loss occurred during the heating process was determined as follows: This is the 5% weight loss temperature (Td5). [Effects of the Invention]

[0010] According to the present invention, there is provided a photosensitive resin composition that reduces the content of N-methyl-2-pyrrolidone, which has a high environmental impact, and that provides a pattern with good rectangularity (tapering). [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a cross-sectional view showing an example of an electronic device having a resin film manufactured from the photosensitive resin composition of the present embodiment as a permanent film. DETAILED DESCRIPTION OF THE INVENTION

[0012] The photosensitive resin composition of the present invention is a photosensitive resin composition containing an alkali-soluble resin and an organic solvent, the alkali-soluble resin contains at least one selected from polyimide, polybenzoxazole, and precursors thereof; the organic solvent comprises a first solvent, The first solvent is at least one selected from dimethyl sulfoxide, N,N-dimethylpropionamide, and propylene glycol monomethyl ether.

[0013] In the photosensitive resin composition according to this embodiment, the first organic solvent is a main solvent used to dissolve or disperse the components of the photosensitive resin composition and provide the photosensitive resin composition as a varnish having a desired viscosity. The first organic solvent in the photosensitive resin composition according to this embodiment is at least one selected from dimethyl sulfoxide, N,N-dimethylpropionamide, and propylene glycol monomethyl ether. By including this solvent as the main solvent, the photosensitive resin composition according to this embodiment can reduce the content of N-methyl-2-pyrrolidone, which has a high environmental impact, and the rectangularity (taperability) of the resulting pattern is excellent. The reason why the rectangularity (tapering) of the resulting pattern is improved when the above-mentioned specific solvents are used as the main solvent is not entirely clear, but it is thought that this is because the alkali-soluble resin has a slightly low solubility in these solvents, and these solvents have lower boiling points than N-methyl-2-pyrrolidone and are more likely to volatilize during the patterning process, thereby reducing the amount of solvent remaining in the cured product. Each component will be described below.

[0014] (alkali-soluble resin) The alkali-soluble resin used in the photosensitive resin composition of this embodiment is polyimide or polybenzoxazole, or a precursor thereof. The alkali-soluble resin may be used alone or in combination of two or more. Specifically, the alkali-soluble resin is a resin having a structure represented by general formula (1).

[0015] [ka]

[0016] In general formula (1), X and Y are organic groups. R1 is a hydroxyl group, -O-R3, an alkyl group, an acyloxy group, or a cycloalkyl group, and when there are multiple R1, they may be the same or different. R2 is a hydroxyl group, a carboxyl group, -O-R3, or -COO-R3, and when there are multiple R2, they may be the same or different. R3 in R1 and R2 is an organic group having 1 to 15 carbon atoms. When there is no hydroxyl group as R1, at least one R2 is a carboxyl group. When there is no carboxyl group as R2, at least one R1 is a hydroxyl group. m is an integer of 0 to 8, and n is an integer of 0 to 8. Examples of the organic group having 1 to 15 carbon atoms as R3 include a formyl group, a methyl group, an ethyl group, a propyl group, an isopropyl group, a tertiary butyl group, a tertiary butoxycarbonyl group, a phenyl group, a benzyl group, a tetrahydrofuranyl group, and a tetrahydropyranyl group.

[0017] The organic group represented by X in the general formula (1) is not particularly limited, but examples thereof include aromatic groups having structures such as benzene rings, naphthalene rings, and bisphenol structures; heterocyclic organic groups having structures such as pyrrole rings and furan rings; and siloxane groups. More specifically, those represented by the following formula (12) are preferred. These may be used alone or in combination of two or more types, as necessary.

[0018] [ka]

[0019] In formula (12), * indicates bonding to the NH group in general formula (1). Z is an alkylene group, a substituted alkylene group, -O-C6H4-O-, -O-, -S-, -SO2-, -C(=O)-, -NHC(=O)- or a single bond. R5 represents one selected from an alkyl group, an alkyl ester group and a halogen atom, and may be the same or different. R6 represents one selected from a hydrogen atom, an alkyl group, an alkyl ester group and a halogen atom. u is an integer of 0 to 4. R7 to R 10 are each a monovalent or divalent organic group. In the above formula (12), the substituent R1 of X in the above general formula (1) is omitted.

[0020] Particularly preferred among the groups represented by the above formula (12) are those represented by the following formula (13) (including those having R1 in general formula (1)).

[0021] [ka]

[0022] In formula (13), * indicates bonding to the NH group in general formula (1). In the formula, Z is an alkylene group, a substituted alkylene group, -O-, -S-, -SO2-, -C(=O)-, -NHC(=O)-, -CH3-, -C(CH3)H-, -C(CH3)2-, -C(CF3)2-, or a single bond. R 11 is one selected from an alkyl group, an alkoxy group, an acyloxy group, and a cycloalkyl group, and R 11 When there are multiple, they may be the same or different. v is an integer of 0 to 3.

[0023] Particularly preferred among the groups represented by the above formula (13) are those represented by the following formula (14) (including those having R1 in general formula (1)).

[0024] [ka]

[0025] In formula (14), * indicates bonding to the NH group in general formula (1). 12 is an organic group selected from an alkylene group, a substituted alkylene group, -O-, -S-, -SO2-, -C(=O)-, -NHC(=O)-, -C(CF3)2-, and a single bond.

[0026] Z in the above formula (12) and formula (13) and R in the above formula (14) 12 Specific examples of alkylene groups and substituted alkylene groups as the alkylene groups include -CH2-, -CH(CH3)-, -C(CH3)2-, -CH(CH2CH3)-, -C(CH3)(CH2CH3)-, -C(CH2CH3)(CH2CH3)-, -CH(CH2CH2CH3)-, -C(CH3)(CH2CH2CH3)-, -CH(CH(CH3)2)-, -C(CH3)(CH(CH3)2)-, -CH(CH2C Examples include -H2CH2CH3)-, -C(CH3)(CH2CH2CH2CH3)-, -CH(CH2CH(CH3)2)-, -C(CH3)(CH2CH(CH3)2)-, -CH(CH2CH2CH2CH2CH3)-, -C(CH3)(CH2CH2CH2CH2CH3)-, -CH(CH2CH2CH2CH2CH2CH3)-, -C(CH3)(CH2CH2CH2CH2CH2CH3)-, -CH(CH2CH2CH2CH2CH2CH3)-, and -C(CH3)(CH2CH2CH2CH2CH2CH3)-. Among these, -CH2-, -CH(CH3)-, and -C(CH3)2- are preferred because they have sufficient solubility not only in alkaline aqueous solutions but also in solvents, allowing the production of a resin film with a better balance.

[0027] Furthermore, Y in the above general formula (1) is an organic group, and examples of such organic groups include the same as those described above for X. Examples include aromatic groups having structures such as a benzene ring, a naphthalene ring, and a bisphenol structure; heterocyclic organic groups having structures such as a pyrrole ring, a pyridine ring, and a furan ring; and siloxane groups, and more specifically, preferred examples include those represented by the following formula (15). These may be used alone or in combination of two or more.

[0028] [ka]

[0029] In formula (15), * indicates bonding to the C=O group in general formula (1). J is -CH2-, -C(CH3)2-, -O-, -S-, -SO2-, -C(=O)-, -NHC(=O)-, -C(CF3)2- or a single bond. R 13 R represents one selected from an alkyl group, an alkyl ester group, an alkyl ether group, a benzyl ether group, and a halogen atom, and may be the same or different. 14 represents one selected from a hydrogen atom, an alkyl group, an alkyl ester group, and a halogen atom. w is an integer of 0 to 2. R 15 ~R 18 are each a monovalent or divalent organic group. In the above formula (15), the substituent R2 of Y in the above general formula (1) is omitted.

[0030] Particularly preferred among these groups represented by formula (15) are those represented by the following formula (16) (including those having R2 in general formula (1)). Regarding the structure derived from the tetracarboxylic dianhydride in the following formula (16), those in which the positions bonding to the C=O group in the general formula (1) are both meta positions and those in which the positions bonding to the C=O group in the general formula (1) are both para positions are given, but structures containing both meta positions and para positions are also acceptable.

[0031] [ka]

[0032] [ka]

[0033] [ka]

[0034] In formula (16), * indicates bonding to the C=O group in general formula (1). 19 R represents one selected from an alkyl group, an alkyl ester group, an alkyl ether group, a benzyl ether group, and a halogen atom, and may be the same or different. 20 represents one selected from a hydrogen atom or an organic group having 1 to 15 carbon atoms, which may be partially substituted, and x is an integer of 0 to 2.

[0035] The alkali-soluble resin is obtained by reacting a dicarboxylic acid compound represented by general formula (2) with a diamine compound represented by general formula (3). More specifically, the alkali-soluble resin is produced by the following (Step 1) and (Step 2): (Step 1) A step of activating a carboxylic acid compound represented by the following general formula (2) to obtain an activated carboxylic acid product. (Step 2) A step of reacting the activated carboxylic acid obtained in the above (Step 1) with an amine compound represented by the following general formula (3) to obtain a resin represented by formula (1).

[0036] [ka]

[0037] In the general formula (2), Y, R2, and n have the same meanings as those in the general formula (1).

[0038] [ka]

[0039] In the general formula (3), X, R1, and m have the same meanings as those in the general formula (1).

[0040] Examples of reaction solvents that can be used in the synthesis of polyamic acid in the above (Step 2) include N-methyl-2-pyrrolidone (NMP), N-ethyl-2-pyridone, N,N-dimethylacetamide, N,N-dimethylformamide, N-acetyl-2-pyrrolidone, hexamethylphosphortriamide, dimethylimidazolidinone, and N-acetyl-ε-caprolactam. However, from the viewpoints of the solubility and reactivity of the amine component and the acid component, and the solubility of the resulting polyimide precursor, it is preferable to use N-methyl-2-pyrrolidone (NMP). As the organic solvent to be mixed with NMP, N,N-dimethylacetamide, N,N-dimethylformamide, N-acetyl-2-pyrrolidone, hexamethylphosphortriamide, dimethylimidazolidinone, N-acetyl-ε-caprolactam, etc. can be used.

[0041] (First organic solvent) The first organic solvent used as the main solvent in the photosensitive resin composition of this embodiment is dimethyl sulfoxide, N,N-dimethylpropionamide, and propylene glycol monomethyl ether. The first organic solvent may be used alone or in combination of two or more.

[0042] The content of the first organic solvent in the photosensitive resin composition can be adjusted according to the desired viscosity appropriate for the application of the photosensitive resin composition. The content of the first organic solvent is, for example, 10 to 80 mass % and preferably 20 to 70 mass % based on the total mass of the photosensitive resin composition. By using the first organic solvent in an amount within the above range, it is possible to reduce the amount of N-methyl-2-pyrrolidone used, which has a high environmental impact, and to improve the rectangularity (tapering) of the obtained pattern.

[0043] In one embodiment, the organic solvent used in the photosensitive resin composition may consist solely of the first organic solvent.

[0044] (Second organic solvent) In the photosensitive resin composition of this embodiment, the second organic solvent used in addition to the first organic solvent is γ-butyl lactone, N-methyl-2-pyrrolidone, or a combination thereof. The second organic solvent is preferably used in an amount of 10 to 80% by mass, and more preferably 15 to 70% by mass, based on the total amount of the organic solvents used.

[0045] The second organic solvent may be a solvent contained in the alkali-soluble resin, specifically, a solvent used in the production and / or purification of the alkali-soluble resin. The synthetic solvent of the alkali-soluble resin can be removed by known methods such as extraction or distillation, but complete removal is difficult. Furthermore, reducing the amount of synthetic solvent may worsen the handleability of the alkali-soluble resin. If little or no synthetic solvent remains in the alkali-soluble resin, the solubility of the alkali-soluble resin may be reduced, and the storage stability of the resin composition may be impaired. By leaving the synthetic solvent in the alkali-soluble resin, the above-mentioned disadvantages can be offset, and the increase in viscosity over time is suppressed, thereby obtaining a photosensitive resin composition with excellent storage stability and handleability. However, if too much synthetic solvent remains in the alkali-soluble resin, the solubility of the coating film of the photosensitive resin composition in the alkaline developer increases, and not only the exposed areas but also the unexposed areas of the coating film dissolve in the alkaline developer to a greater extent. As a result, residues are generated at the bottom of the openings corresponding to the exposed areas. In the photosensitive resin composition of the present embodiment, by adjusting the amount of the second organic solvent within an optimum range, a varnish-like photosensitive resin composition can be obtained without impairing the handleability of the resin composition, and the pattern of the obtained photosensitive resin composition can have improved rectangularity (tapering).

[0046] The first organic solvent and the second organic solvent can be used in a specific combination. For example, a photosensitive resin composition can be prepared by appropriately selecting the first organic solvent depending on the second organic solvent contained in the alkali-soluble resin used. This allows the solubility of the alkali-soluble resin to be adjusted, thereby improving the storage stability and handleability of the resulting photosensitive resin composition and further improving the rectangularity (tapering) of the pattern of the resulting photosensitive resin composition. Preferred combinations of the first organic solvent and the second organic solvent include, for example, a combination in which the first organic solvent is dimethyl sulfoxide and the second organic solvent is γ-butyllactone and N-methyl-2-pyrrolidone; a combination in which the first organic solvent is N,N-dimethylpropionamide and the second organic solvent is γ-butyllactone and N-methyl-2-pyrrolidone; and a combination in which the first organic solvent is propylene glycol monomethyl ether and the second organic solvent is γ-butyllactone and N-methyl-2-pyrrolidone.

[0047] When N-methyl-2-pyrrolidone is used as the second organic solvent, its use is undesirable from the viewpoint of environmental impact, and therefore, its amount is preferably 50% by mass or less, more preferably 45% by mass or less, and even more preferably 40% by mass or less, based on the entire photosensitive resin composition. When N-methyl-2-pyrrolidone is used as the second organic solvent, by setting the amount used within the above range, a photosensitive resin composition can be obtained in which the rectangularity (tapering) of the pattern is improved without impairing the solubility of the alkali-soluble resin.

[0048] In one embodiment, the organic solvent used in the photosensitive resin composition may consist of the first organic solvent and the second organic solvent.

[0049] [Production of Photosensitive Resin Composition] The photosensitive resin composition of this embodiment can be produced by dissolving the alkali-soluble resin and, if necessary, other components in a first organic solvent and / or a second organic solvent. From the viewpoint of ease of handling, the photosensitive resin composition of this embodiment is preferably provided in the form of a solution dissolved in an organic solvent. Examples of other components that may be used as necessary include a photoacid generator, a photopolymerization initiator, a thermal crosslinking agent, a thermal acid generator, an adhesion aid, a dissolution adjuster, and a surfactant.

[0050] The alkali-soluble resin used is obtained in the form of a resin mixture containing the synthesis solvent, other components used in the synthesis process, and impurities such as unreacted raw materials and by-products. Before producing the photosensitive resin composition, the resin mixture may be subjected to a separation operation and / or a concentration operation to isolate and purify the alkali-soluble resin. Alternatively, the mixture may be subjected to a concentration operation to reduce the amount of the synthesis solvent or to remove the synthesis solvent.

[0051] Methods for dissolving the alkali-soluble resin in the first organic solvent and / or the second organic solvent include stirring and heating. When heating, the heating temperature is preferably set within a range that does not impair the performance of the alkali-soluble resin, and is usually room temperature (25°C) to 80°C. The order in which the components are dissolved is not particularly limited; for example, the components with the lowest solubility may be dissolved in order. When using a first organic solvent and a second organic solvent, these solvents may be mixed in advance to form a mixed solvent, and the alkali-soluble resin may be dissolved in this mixed solvent. Alternatively, the alkali-soluble resin may be first dissolved in one of the solvents, and then the remaining solvent may be added.

[0052] [Uses of photosensitive resin compositions] A resin film can be produced by curing the photosensitive resin composition of this embodiment. The resulting resin film can be used as a permanent film such as a protective film, an interlayer film, or a dam material. This can improve the heat resistance and durability of an electronic device equipped with the resin film as a permanent film.

[0053] (Method of manufacturing patterned cured film) The method for producing a pattern of the present invention includes the steps of applying a photosensitive resin composition onto a substrate and drying it to obtain a resin film, exposing the resin film to a predetermined pattern and developing it to obtain a patterned resin film, and heat-treating the patterned resin film. The method for producing a patterned cured film is described below.

[0054] First, the photosensitive resin composition is coated onto a support substrate. The support substrate may be, but is not limited to, a silicon wafer, ceramics, gallium arsenide, metal, glass, a metal oxide insulating film, silicon nitride, or ITO. Coating methods include spin coating using a spinner, spray coating, roll coating, and slit die coating. The coating thickness varies depending on the coating method, the solids concentration, and viscosity of the photosensitive heat-resistant resin composition, but it is generally coated so that the film thickness after drying is 0.1 to 150 μm.

[0055] Next, the support substrate coated with the photosensitive resin composition is dried to obtain a photosensitive coating film. This process is also called pre-baking. Drying is preferably carried out using an oven, hot plate, infrared rays, or the like at a temperature ranging from 70 to 130°C for 1 minute to several hours. When using a hot plate, the coating film is heated directly on the plate or held on a jig such as a proxy pin placed on the plate. Proxy pins can be made of metal materials such as aluminum or stainless steel, or synthetic resins such as polyimide resin or Teflon (registered trademark). Any heat-resistant proxy pin material can be used. The height of the proxy pins varies depending on the size of the support substrate, the type of coating film, and the purpose of heating, but is preferably 0.1 to 10 mm.

[0056] Next, the photosensitive coating film is patterned. Specifically, the photosensitive coating film is exposed to actinic radiation through a mask having a desired pattern. Actinic radiation used for exposure includes ultraviolet light, visible light, electron beams, and X-rays, but it is preferable to use i-rays (wavelength 365 nm), h-rays (wavelength 405 nm), and g-rays (wavelength 436 nm) from a mercury lamp. If the film has positive photosensitivity, the exposed area will dissolve in the developer. If the film has negative photosensitivity, the exposed area will harden and become insoluble in the developer.

[0057] After exposure, the photosensitive coating film is treated with a developer to remove the exposed areas, forming a pattern. The developer is preferably an aqueous solution of an alkaline compound such as tetramethylammonium hydroxide, diethanolamine, diethylaminoethanol, sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, triethylamine, diethylamine, methylamine, dimethylamine, dimethylaminoethyl acetate, dimethylaminoethanol, dimethylaminoethyl methacrylate, cyclohexylamine, ethylenediamine, or hexamethylenediamine. In some cases, these alkaline aqueous solutions may contain one or more polar solvents such as N-methyl-2-pyrrolidone, N,N-dimethylformamide, N,N-dimethylacetamide, dimethylsulfoxide, γ-butyrolactone, or dimethylacrylamide; alcohols such as methanol, ethanol, or isopropanol; esters such as ethyl lactate or propylene glycol monomethyl ether acetate; or ketones such as cyclopentanone, cyclohexanone, isobutyl ketone, or methyl isobutyl ketone. After development, the film is typically rinsed with water. For the rinsing treatment, one or more of alcohols such as ethanol and isopropyl alcohol, and esters such as ethyl lactate, propylene glycol monomethyl ether acetate and 3-methoxymethyl propanoate may be added to the water.

[0058] After development, the resulting coated film pattern is converted into a pattern-cured film by heating at a temperature range of 150 to 400°C. This heat treatment is preferably carried out by selecting an appropriate temperature and gradually increasing the temperature, or by selecting a temperature range and continuously increasing the temperature for 5 minutes to 5 hours. Examples include a method of heat treating at 130°C, 200°C, and 300°C for 30 minutes each, or a method of linearly increasing the temperature from room temperature to 300°C over 2 hours.

[0059] The resulting resin film can be used as a permanent film such as a protective film, an interlayer film, or a dam material.

[0060] (Application) Next, an example of an electronic device 100 to which the photosensitive resin composition of this embodiment is applied will be described. The electronic device 100 shown in FIG. 1 is, for example, a semiconductor chip. In this case, a semiconductor package is obtained by mounting the electronic device 100 on a wiring substrate via bumps 52. The electronic device 100 includes a semiconductor substrate on which semiconductor elements such as transistors are provided, and a multilayer wiring layer provided on the semiconductor substrate (not shown). The uppermost layer of the multilayer wiring layer includes an interlayer insulating film 30 and a top-layer wiring 34 provided on the interlayer insulating film 30. The top-layer wiring 34 is made of, for example, Al. A passivation film 32 is provided on the interlayer insulating film 30 and the top-layer wiring 34. An opening is provided in a part of the passivation film 32, through which the top-layer wiring 34 is exposed.

[0061] A redistribution layer 40 is provided on the passivation film 32. The redistribution layer 40 has an insulating layer 42 provided on the passivation film 32, a redistribution line 46 provided on the insulating layer 42, and an insulating layer 44 provided on the insulating layer 42 and the redistribution line 46. An opening connected to the top-layer wiring 34 is formed in the insulating layer 42. The redistribution line 46 is formed on the insulating layer 42 and in the opening provided in the insulating layer 42, and is connected to the top-layer wiring 34. An opening connected to the redistribution line 46 is formed in the insulating layer 44.

[0062] In this embodiment, one or more of the passivation film 32, the insulating layer 42, and the insulating layer 44 can be formed of a resin film formed by, for example, curing the above-mentioned photosensitive resin composition. In this case, for example, a coating film formed from a photosensitive resin material is exposed to ultraviolet light, developed to be patterned, and then heated and cured to form the passivation film 32, the insulating layer 42, or the insulating layer 44.

[0063] Bumps 52 are formed in the openings provided in the insulating layer 44 via, for example, an under bump metallurgy (UBM) layer 50. The electronic device 100 is connected to a wiring board or the like via the bumps 52, for example.

[0064] Although the embodiments of the present invention have been described above, these are merely examples of the present invention, and various other configurations can also be adopted. [Example]

[0065] EXAMPLES The present invention will be described below with reference to examples and comparative examples, but the present invention is not limited to these.

[0066] [Synthesis of alkali-soluble resin] An alkali-soluble resin was synthesized by the following method.

[0067] (Synthesis Example 1) 258.2 g (1 mol) of diphenyl ether-4,4'-dicarboxylic acid and 270.3 g (2 mol) of 1-hydroxybenzotriazole were dissolved in 1500 g of N-methyl-2-pyrrolidone (NMP), and 412.7 g (2 mol) of dicyclohexylcarbodiimide dissolved in 412 g of solvent 1 was added dropwise over 2 hours while maintaining the internal temperature at 0-5°C. After the addition, the internal temperature was returned to room temperature, and the reaction was continued with stirring for an additional 12 hours. After the reaction was completed, the precipitated dicyclohexylcarbodiurea was removed by filtration, and 4000 g of purified water was added dropwise to the resulting filtrate to precipitate crystals. The crystals were collected by filtration, washed with 8000 ml of isopropyl alcohol, and then vacuum-dried to obtain 467 g of dicarboxylic acid derivative. 40.87 g (0.083 mol) of the resulting dicarboxylic acid derivative and 36.63 g (0.1 mol) of 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane were placed in a four-neck separable flask equipped with a thermometer, a stirrer, a raw material inlet, and a dry nitrogen gas inlet tube, and solvent 1 (180.8 g) was added and dissolved. The mixture was then heated to 75 °C using an oil bath while flowing nitrogen, and reacted at 75 °C for 12 hours. Next, 5.58 g (0.034 mol) of 3,6-endomethylene-1,2,3,6-tetrahydrophthalic anhydride dissolved in solvent 1 (13.0 g) was added, and the mixture was stirred for an additional 3 hours. The mixture was then cooled to room temperature to terminate the reaction. Next, the reaction mixture was filtered, and then poured into a solution of water / isopropyl alcohol = 3 / 1. The precipitate was collected by filtration, washed thoroughly with water, and then dried under vacuum to obtain a precursor having an amide bond with a repeating unit of general formula (A-1) (a resin that undergoes dehydration ring closure when heated at 300 to 400 °C to become polybenzoxazole, alkali-soluble resin 1).

[0068] The obtained alkali-soluble resin 1 had the repeating unit (A-1) shown below.

[0069] [ka]

[0070] [Preparation of Photosensitive Resin Composition] (Examples 1 to 6, Comparative Examples 1 to 5) A resin composition was prepared according to the formulation shown in Table 1. Specifically, the alkali-soluble resin obtained in the above synthesis example was dissolved in the first organic solvent and the second organic solvent in the amounts shown in Table 1, and a photoacid generator was added, followed by the addition of other components to obtain a photosensitive resin composition. The components shown in Table 1 are as follows:

[0071] (alkali-soluble resin) Alkali-soluble resin 1: Alkali-soluble resin 1 synthesized in Synthesis Example 1

[0072] (First organic solvent) Dimethyl sulfoxide (DMSO) N,N-dimethylpropionamide (DMPA) Propylene glycol monomethyl ether (PGMEA) (Second organic solvent) γ-Butyllactone (GBL) N-methyl-2-pyrrolidone (NMP)

[0073] (Other organic solvents) 3-Methoxy-N,N'-dimethylpropanamide Propylene glycol monomethyl ether (PGME) Benzyl alcohol

[0074] (Photoacid generator) Photoacid generator 1: a compound represented by formula (B-2) synthesized by the following method: (Synthesis of compound represented by formula (B-2)) A four-neck separable flask equipped with a thermometer, stirrer, raw material inlet, and dry nitrogen gas inlet was charged with 11.04 g (0.026 mol) of phenol represented by formula (B-1), 18.81 g (0.070 mol) of 1,2-naphthoquinone-2-diazide-4-sulfonyl chloride, and 170 g of acetone, and the mixture was stirred to dissolve. Next, a mixed solution of 7.78 g (0.077 mol) of triethylamine and 5.5 g of acetone was slowly added dropwise while cooling the flask in a water bath to prevent the temperature of the reaction solution from exceeding 35°C. After reacting for 3 hours at room temperature, 1.05 g (0.017 mol) of acetic acid was added and the reaction was continued for another 30 minutes. The reaction mixture was then filtered, and the filtrate was poured into a mixed solution of water / acetic acid (990 ml / 10 ml). The precipitate was then collected by filtration, thoroughly washed with water, and dried under vacuum. This yielded a compound represented by the structure of formula (B-2).

[0075] [ka]

[0076] (adhesion aid) Adhesion aid 1: 3-methacryloxypropyltrimethoxysilane (Shin-Etsu Silicone Co., Ltd.) (solubility enhancer) Dissolution enhancer 1: 2,2'-dihydroxydiphenylmethane

[0077] [Performance evaluation of photosensitive resin composition] The photosensitive resin compositions obtained above were each evaluated for performance in the following items. The evaluation results are shown in Table 1.

[0078] (Rectangularity (tapering)) The rectangularity of the pattern of the photosensitive resin composition was evaluated using the taper angle as an index. First, the photosensitive resin composition of each example was applied to an 8-inch silicon wafer using a spin coater, and then prebaked on a hot plate at 120°C for 4 minutes to obtain a coating film with a thickness of approximately 9.8 μm. The obtained coating film was heat-treated at 300°C for 60 minutes in a nitrogen atmosphere. Next, the heat-treated coating film was irradiated with 500 mJ / cm using an i-line stepper (Nikon NSR-4425i) through a mask (manufactured by Toppan Printing Co., Ltd.) (having a line-shaped cutout pattern of 10 to 100 μm drawn on it). 2 Next, a 2.38% aqueous solution of tetramethylammonium hydroxide was used as the developer, and puddle development was performed twice, adjusting the development time so that the difference in film thickness between the pre-baked and developed layers was 2.0 μm, to dissolve and remove the exposed areas, followed by rinsing with pure water for 10 seconds to obtain a pattern. The cross section of the 40 μm line-shaped cutout pattern in the obtained pattern was checked, and the angle drawn from the contact point on the wafer to the tangent line of the arc-shaped remaining pattern portion was measured, and this measured angle was taken as the taper angle (°). A taper angle of 40° or more is preferable because the cross-sectional shape of the pattern is close to a rectangle and bonding with adjacent patterns can be suppressed. Also, a taper angle of 60° or less can suppress the occurrence of shadows that prevent deposition during deposition of the pattern film.

[0079] (Heat resistance) The heat resistance of the photosensitive resin composition was evaluated using the 5% weight loss temperature as an index. First, the photosensitive resin composition of each example was heated at 300°C for 60 minutes in a nitrogen atmosphere to obtain a cured product. Next, 10 g of the obtained cured product was heated from 25°C to 600°C at a heating rate of 10°C min in an air atmosphere. During the heating, the temperature at which a 5% thermal weight loss occurred was measured and recorded as the 5% weight loss temperature (Td5). When the 5% weight loss temperature (Td5) is 370° C. or higher, the heat resistance is excellent. When the Td5 is 410° C. or lower, the residual solvent is suppressed.

[0080]

Table 1

Claims

1. an alkali-soluble resin, and an organic solvent; the alkali-soluble resin contains at least one selected from polyimide, polybenzoxazole, and precursors thereof; the organic solvent comprises a first solvent, The first solvent is at least one selected from dimethyl sulfoxide, N,N-dimethylpropionamide, and propylene glycol monomethyl ether. Photosensitive resin composition.

2. The photosensitive resin composition according to claim 1, the organic solvent further comprises a second solvent; The photosensitive resin composition, wherein the second solvent is at least one selected from the group consisting of γ-butyl lactone and N-methyl-2-pyrrolidone.

3. The photosensitive resin composition according to claim 2, the organic solvent includes the first solvent and the second solvent, The photosensitive resin composition, wherein the first solvent is contained in an amount of 10% by mass or more and 80% by mass or less based on the total amount of the organic solvent.

4. The photosensitive resin composition according to claim 2, the organic solvent includes N-methyl-2-pyrrolidone, The photosensitive resin composition, wherein the amount of N-methyl-2-pyrrolidone is 50% by mass or less based on the total amount of the photosensitive resin composition.

5. The photosensitive resin composition according to claim 1, The photosensitive resin composition, wherein the organic solvent consists solely of the first solvent.

6. The photosensitive resin composition according to claim 2, The photosensitive resin composition, wherein the organic solvent comprises the first solvent and the second solvent.

7. The photosensitive resin composition according to claim 1, A photosensitive resin composition having a taper angle of 40° or more and 60° or less when measured under the following condition 1: (Condition 1) Pattern formation conditions: The photosensitive resin composition is applied to an 8-inch silicon wafer using a spin coater, and then pre-baked on a hot plate at 120°C for 4 minutes to obtain a coating film with a thickness of approximately 9.8 μm. The coating film is then heat-treated at 300°C for 60 minutes in a nitrogen atmosphere. Next, the heat-treated coating film is irradiated with 500 mJ / cm using an i-line stepper (Nikon Corporation, NSR-4425i) through a mask (manufactured by Toppan Printing Co., Ltd.) (on which a line-shaped cutout pattern of 10 to 100 μm is drawn). ２ The photosensitive resin composition is then irradiated with an exposure dose of 1000 .mu.m. Next, using a 2.38% aqueous solution of tetramethylammonium hydroxide as the developer, puddle development is performed twice, adjusting the development time so that the difference in film thickness between the pre-baked and developed layers is 2.0 μm, to dissolve and remove the exposed areas, followed by rinsing with pure water for 10 seconds to obtain a pattern. The photosensitive resin composition is then heated at 300°C for 60 minutes in a nitrogen atmosphere to obtain a cured product. Taper angle measurement conditions: Check the cross section of the 40 μm line-shaped cutout pattern in the pattern. Measure the angle drawn from the contact point on the wafer to the tangent of the arc-shaped remaining pattern portion, and use this angle as the taper angle (°).

8. The photosensitive resin composition according to claim 1, A photosensitive resin composition having a 5% weight loss temperature of 370°C or higher and 410°C or lower when measured under the following condition 2: (Condition 2) Curing conditions: The photosensitive resin composition is heated in a nitrogen atmosphere at 300° C. for 60 minutes to obtain a cured product. 5% weight loss temperature measurement conditions: 10 mg of the cured product was heated from 25°C to 600°C at a heating rate of 10°C min in an air atmosphere. The temperature at which a 5% thermal weight loss occurred during the heating was determined as follows: This is the 5% weight loss temperature (Td5).

Images