Photosensitive resin composition and cured film thereof, and interlayer insulating film and semiconductor protective film using said cured film

Abstract

The present invention addresses the problem of providing: a photosensitive resin composition which, when used to form a film-like shape, exhibits high opening properties and excellent uniformity when an opening pattern is formed by exposure, development, and curing; a cured film obtained by curing a film of the photosensitive resin composition; and an interlayer insulating film or a semiconductor protective film using the cured film. In order to solve the problem, provided is a photosensitive resin composition containing: at least a resin selected from the group consisting of polyimide, polybenzoxazole, polyamide, precursors thereof, and copolymers thereof; a resin selected from the group consisting of a phenolic resin and polyhydroxystyrene; and a photosensitizer, wherein a resin film obtained by applying the photosensitive resin composition to a substrate and subjecting the same to heat treatment exhibits a phase-separated structure.

Description

Photosensitive resin composition and cured film thereof, and interlayer insulating film and semiconductor protective film using the cured film

[0001] The present invention relates to a photosensitive resin composition, a cured film obtained from the photosensitive resin composition, and an interlayer insulating film and a semiconductor protective film using the cured film.

[0002] Polyimide resins, polybenzoxazole resins, and the like, which have excellent heat resistance and mechanical properties, are widely used for surface protection films and interlayer insulating films of semiconductor elements in electronic devices.

[0003] When polyimide is used as a surface protective film or interlayer insulating film for semiconductor devices, one method for forming through-holes is to use a positive photoresist as a mask and then etch the through-holes. However, this method involves the application and removal of the photoresist, which is a complex process. Therefore, heat-resistant materials that are also photosensitive have been investigated to streamline the process.

[0004] As photosensitive materials, materials using quinone diazide compounds as photosensitizers have been proposed, and among them, systems in which novolac resins or polyhydroxystyrene resins are added to heat-resistant resins have been proposed as a method for increasing sensitivity (for example, Patent Document 1).

[0005] Japanese Patent Application Laid-Open No. 2005-352004

[0006] However, when a heat-resistant resin and a novolac resin are mixed, the compatibility between the resins is low, resulting in a large degree of phase separation when the resulting film is formed, which poses a problem of non-uniform pattern opening within the wafer surface during pattern processing on a silicon wafer.

[0007] The present invention has been made in view of the above-mentioned problems, and aims to provide a photosensitive resin composition in film form that exhibits high opening properties and excellent uniformity when exposed to light, developed, and cured to form an opening pattern, a cured film thereof, and an interlayer insulating film or semiconductor protective film using the same.

[0008] In order to solve the above problems, the photosensitive resin composition of the present invention has the following configuration: a photosensitive resin composition containing at least a resin selected from the group consisting of polyimide, polybenzoxazole, polyamide, precursors thereof, and copolymers thereof, a resin selected from the group consisting of phenolic resin and polyhydroxystyrene, and a photosensitizer, wherein the photosensitive resin composition is applied to a substrate and heat-treated to produce a resin film exhibiting a phase-separated structure.

[0009] The present invention also relates to a cured film obtained by curing a film of the photosensitive resin composition, and to an interlayer insulating film or a semiconductor protective film using the cured film.

[0010] According to the present invention, it is possible to obtain a photosensitive resin composition which is highly sensitive, has a film-like form, and exhibits high opening properties when exposed to light, developed, and cured to form an opening pattern, and which also exhibits excellent pattern uniformity.

[0011] The present invention provides a photosensitive resin composition comprising at least a resin selected from the group consisting of polyimide, polybenzoxazole, polyamide, and precursors thereof and copolymers thereof (hereinafter, such a resin may be referred to as "resin (A)"), a resin selected from the group consisting of phenolic resin and polyhydroxystyrene (hereinafter, such a resin may be referred to as "resin (B)"), and a photosensitizer, wherein the photosensitive resin composition is applied to a substrate and heat-treated to obtain a resin film exhibiting a phase-separated structure.

[0012] The photosensitive resin composition of the present invention can ensure solubility in an alkaline developer by containing an alkali-soluble resin (such as resin (A) and / or resin (B)). Here, the term "alkali-soluble resin" refers to a resin whose dissolution rate in an alkaline aqueous solution as a developer is 50 nm / min or more for a film-like resin composition. Specifically, the term "alkali-soluble resin" refers to a resin obtained by applying a solution of the resin dissolved in γ-butyrolactone to a silicon wafer and prebaking the resulting film on a hot plate at 120°C for 4 minutes to form a prebaked film having a thickness of 10 μm±0.5 μm. The prebaked film is then immersed in a 2.38 mass% aqueous solution of tetramethylammonium hydroxide at 23±1°C for 1 minute, followed by rinsing with pure water. The dissolution rate is determined from the amount of film thickness reduction of 50 nm / min or more.

[0013] The photosensitive resin composition of the present invention can obtain high heat resistance by using the resin (A).

[0014] For example, a polyimide precursor can be obtained by reacting a tetracarboxylic acid, a corresponding tetracarboxylic dianhydride, a tetracarboxylic diester dichloride, or the like with a diamine, a corresponding diisocyanate compound, or a trimethylsilylated diamine. A polyimide can be obtained, for example, by dehydrating and cyclizing the polyimide precursor obtained by the above method by heating or a chemical treatment with an acid or a base.

[0015] Polyamides can be obtained by reacting dicarboxylic acids, corresponding dicarboxylic dianhydrides, dicarboxylic acid diester dichlorides, etc. with diamines, corresponding diisocyanate compounds, and trimethylsilylated diamines.

[0016] A polybenzoxazole precursor can be obtained by reacting a bisaminophenol with a dicarboxylic acid, a corresponding dicarboxylic acid chloride, a dicarboxylic acid activated ester, etc. Polybenzoxazole can be obtained, for example, by dehydrating and cyclizing the polybenzoxazole precursor obtained by the above method through heating or a chemical treatment with phosphoric anhydride, a base, a carbodiimide compound, or the like.

[0017] The resin (A) preferably has at least one repeating unit selected from the repeating units shown below.

[0018]

[0019] X in the above repeating unit １ is an acid dianhydride residue, X ２ is a tetracarboxylic acid residue or a tricarboxylic acid residue, X ３ represents a dicarboxylic acid residue, Y １ (OH) ｐ , Y ２ (OH) ｑ and Y ３ (OH) ｒ Each of p, q, and r represents an integer ranging from 0 to 4, and R １ represents a hydrogen atom or an organic group having 1 to 10 carbon atoms, and s represents 1 or 2.

[0020] Examples of the organic group having 1 to 10 carbon atoms include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, a nonyl group, an isopropyl group, and a tert-butyl group.

[0021] Known compounds can be used as compounds that provide the acid dianhydride residue, tetracarboxylic acid residue, tricarboxylic acid residue, dicarboxylic acid residue and diamine residue.

[0022] In order to improve the storage stability of the resin (A), it is preferable to cap the main chain ends with a terminal capping agent such as a monoamine, an acid anhydride, a monocarboxylic acid, a monoacid chloride compound, or a monoactive ester compound.

[0023] Known monoamines, acid anhydrides, monocarboxylic acids, monoacid chloride compounds, and monoactive ester compounds can be used.

[0024] The introduction ratio of the monoamine used as the end-capping agent is preferably 0.1 mol% or more, particularly preferably 5 mol% or more, and preferably 40 mol% or less, particularly preferably 30 mol% or less, when the total amount of diamine and monoamine introduced into the resin is taken as 100 mol%. The introduction ratio of the acid anhydride, monocarboxylic acid, monoacid chloride compound, or monoactive ester compound used as the end-capping agent is preferably 0.1 mol% or more, particularly preferably 5 mol% or more, based on the diamine component. On the other hand, in order to maintain a high molecular weight of the resin, the introduction ratio is preferably 100 mol% or less, particularly preferably 90 mol% or less. Multiple different end groups may be introduced by reacting multiple end-capping agents.

[0025] The amount of the end-capping agent corresponding to the end groups introduced into the resin (A) can be detected by the following method. For example, the resin into which the end groups have been introduced is dissolved in an acidic solution, decomposed into the structural units of amine components and acid anhydride components, and then subjected to gas chromatography (GC) or nuclear magnetic resonance (NMR) measurement. Separately, the resin component into which the end groups have been introduced can be directly subjected to pyrolysis gas chromatography (PGC), infrared spectroscopy, and １３ It can also be detected by measuring with a C-NMR spectrum.

[0026] The alkaline dissolution rate (R(A)) of the resin (A) used in the present invention is preferably 100 nm / min or more, more preferably 500 nm / min or more, and even more preferably 1,000 nm / min or more from the viewpoint of shortening the development time, and is preferably 10,000 nm / min or less, more preferably 5,000 nm / min or less, and even more preferably 2,000 nm / min or less from the viewpoint of improving the pattern shape.

[0027] The polystyrene-equivalent weight average molecular weight (Mw(A)) of the resin (A) is preferably 5,000 or more, more preferably 10,000 or more, and even more preferably 20,000 or more from the viewpoint of the mechanical properties of the cured film, and is preferably 100,000 or less, more preferably 40,000 or less, and even more preferably 34,000 or less from the viewpoint of alkali solubility. The weight average molecular weight can be determined by gel permeation chromatography (GPC).

[0028] The photosensitive resin composition of the present invention contains the resin (B), and therefore can provide high sensitivity when processed into a film.

[0029] Examples of resin (B) include novolak resins, resol resins, benzyl ether type phenolic resins, and polyhydroxystyrenes, but are not limited to these as long as they are phenolic resins or polyhydroxystyrenes. Two or more of these may also be used.

[0030] Novolak resins can be obtained by polycondensing phenols and aldehydes such as formalin by a known method.

[0031] The polyhydroxystyrene used as the resin (B) can be obtained, for example, by addition polymerization of a phenol derivative in which an unsaturated double bond is directly bonded to a benzene ring, by a known method.

[0032] The alkali dissolution rate (R(B)) of the resin (B) used in the present invention is preferably 500 nm / min or more, more preferably 1000 nm / min or more, and even more preferably 3000 nm / min or more from the viewpoint of shortening the development time, and is preferably 30,000 nm / min or less, more preferably 20,000 nm / min or less, and even more preferably 15,000 nm / min or less from the viewpoint of improving the pattern shape.

[0033] The polystyrene-equivalent weight average molecular weight (Mw(B)) of the resin (B) is preferably 500 or more, more preferably 1,000 or more, and even more preferably 2,000 or more from the viewpoint of chemical resistance, and is preferably 40,000 or less, more preferably 10,000 or less, and even more preferably 5,000 or less from the viewpoint of alkali solubility.

[0034] The phase-separated structure referred to in the present invention mainly refers to a phase-separated state that occurs when two or more types of polymers are mixed, and can be observed by the following method.

[0035] The phase separation structure can be observed by cutting out a thin film sample approximately 100 nm thick from a resin film (including a resin film after heat treatment and a cured film obtained by curing the resin film) made from a photosensitive resin composition, and observing the cross section of the resin film using a transmission electron microscope. Any location within the film thickness range can be observed. The observed image is binarized using image analysis software, and a phase separation structure is defined as one in which the area ratio of one of the binarized portions (referred to as "one phase") (one phase area ratio) is 20 to 70% of the entire image. The specific method for calculating the phase area ratio is as follows.

[0036] A cross section of the resin film is observed using a transmission electron microscope at a magnification of 10,000 to 30,000 times, and an area equivalent to a 2 μm square film area is cut out from the obtained image. The image is converted to 16-bit using the image analysis software "ImageJ", and then smoothed. At this time, a Gaussian filter of σ = 2.0 is used. Next, the image background is subtracted. At this time, the rolling ball radius is set to 30 pixels. Next, the contrast of the image is enhanced. At this time, the number of saturated pixels is set to 0.35%. Next, the image is binarized by setting a threshold value using IsoData Auto, and the area ratio of the colored area to the entire image is calculated. Areas where the area ratio of the colored area is 20 to 70% are considered to "exhibit a phase separation structure."

[0037] When the area ratio of one phase is in the range of 20 to 70% of the entire image, the degree of phase separation is suitable for obtaining the characteristics of each resin in the polymer blend. The area ratio of one phase is more preferably 25 to 60% of the entire image, and even more preferably 30 to 50%. This range effectively achieves the high heat resistance and mechanical properties of resin (A) and the high processing sensitivity of resin (B). Furthermore, uniform alkali solubility is achieved within the surface during pattern processing, resulting in highly uniform pattern opening and suppressing cloudiness after development.

[0038] Furthermore, as for the phase separation structure, when each individual phase detected in the observation image by binarizing it using the image analysis software, i.e., a unit in the image in which one phase is surrounded by other parts (sometimes referred to as an "island domain"), is plotted with the area of ​​each phase on the horizontal axis and the sum of the brightnesses of the detected phases on the vertical axis, the slope a of the approximation equation y = ax + b when the plot is approximated as a straight line is preferably -1.0 to -30.0, more preferably -1.5 to -10.0, and even more preferably -2.0 to -5.0. By being in this range, the size of the phase separation domain in the resin film becomes the size most suitable for improving heat resistance, mechanical properties, and sensitivity during processing, and pattern opening properties with high in-plane uniformity can be obtained.

[0039] The method for calculating the slope a will be described in more detail. Similar to the method for observing the phase separation structure described above, a thin film sample approximately 100 nm thick is cut out from a resin film made from a photosensitive resin composition, and the cross section of the resin film is observed using a transmission electron microscope. Any location within the film thickness range can be observed. A 2 μm square area is cut out from the obtained image, and the image is converted to 32 bits using the image analysis software "ImageJ." Noise is reduced using a Gaussian filter σ = 2.0, and background subtraction is performed using a rolling ball radius of 30 pixels. Next, the threshold determination algorithm is set to "Default" to binarize the image. For areas recognized as black foreground, the area value of the island domain to be analyzed is set to "100 pixels^2 - Infinity" to calculate the sum of brightness (IntDen). However, island domains that are not entirely visible in the image are excluded. A scatter diagram of the analysis results is plotted with the area of ​​the island domains (Area) on the X axis and the sum of brightness (IntDen) on the Y axis, and a linear approximation equation (regression equation using a linear function) is drawn for the plot, with the slope being slope a.

[0040] The photosensitive resin composition of the present invention is applied to a substrate and heat-treated to produce a resin film with a phase-separated structure. Application to the substrate can be achieved by spin coating using a spinner, spray coating, roll coating, slit die coating, or other methods. The resin film thickness varies depending on the application technique, solids concentration, viscosity, and other factors, but preferably ranges from 0.5 to 20 μm after heat treatment. The heat treatment can be performed immediately after application (pre-baking) or after pattern processing (curing). The photosensitive resin composition of the present invention exhibits a phase-separated structure after pre-baking. Preferably, the cured film also exhibits a phase-separated structure after curing. Pre-baking is performed using a hot plate at 80 to 150°C for 1 to 30 minutes, preferably at 100 to 130°C for 1 to 5 minutes, with 120°C being particularly preferred. Curing can be performed using an oven, hot plate, infrared, or the like, by applying a temperature of 150 to 400°C to convert the composition into a heat-resistant resin film. This treatment is preferably carried out for 30 minutes to 3 hours by selecting a temperature and increasing the temperature stepwise, or by selecting a temperature range and continuously increasing the temperature. When the temperature is increased or decreased continuously, the temperature increase rate is preferably 1 to 10°C / min, more preferably 2 to 5°C / min, in order to obtain a phase-separated structure. The temperature decrease rate is preferably 1 to 10°C / min, more preferably 2 to 5°C / min. For example, after treatment at 150°C for 30 minutes using an oven under a nitrogen atmosphere, the temperature is increased at a rate of 5°C / min, treated at 320°C for 1 hour, and then decreased to 100°C or less at a rate of 4°C / min.

[0041] In the photosensitive resin composition of the present invention, the content of resin (B) is preferably 15 to 200 parts by mass, more preferably 50 to 200 parts by mass, and even more preferably 100 to 150 parts by mass, per 100 parts by mass of resin (A), so that a phase-separated structure can be easily realized and the surface roughness and contact angle described below can be within preferred ranges. Furthermore, the ratio of Mw(A) to Mw(B), (Mw(A) / Mw(B)), is preferably 1 to 20, more preferably 5 to 10, and even more preferably 7 to 10.

[0042] In the photosensitive resin composition of the present invention, in order to easily achieve a phase-separated structure, all or a portion of the carboxyl group terminals of resin (A) preferably have a structure represented by formula (1) or (2), and the solubility parameter (SP value) of the amine that reacts with the carboxyl group terminals to give the structure represented by formula (1) or (2) is preferably 8.0 to 16.0, more preferably 10.0 to 12.0. The amide or imide group in formula (1) or (2) represents a carbonyl group derived from the carboxyl group terminal. The solubility parameter (SP value) was determined using the value described in "Coating Basic Science" (page 65, Yuji Harasaki, Maki Shoten). For materials not described in the literature, the SP value was calculated using the Fedors formula from the evaporation energy and molar volume of atoms and atomic groups in "Coating Basic Science" (page 55, Yuji Harasaki, Maki Shoten). The compound can be obtained by using, for example, a monoamine as an amine or end-capping agent that reacts with the carboxyl terminal to give the structure of formula (1) or (2). In this case, R １ or R ２represents a monoamine residue. When a monoamine is used as the end-capping agent, the SP value of the monoamine is preferably 8.0 to 16.0, more preferably 10.0 to 12.0. Examples of the resin (A) having a terminal represented by formula (1) include polyimide precursors. Examples of the resin (A) having a terminal represented by formula (1) include polyimides. Examples of monoamines include aniline, 2-ethynylaniline, 3-ethynylaniline, 4-ethynylaniline, 5-amino-8-hydroxyquinoline, 1-hydroxy-7-aminonaphthalene, 1-hydroxy-6-aminonaphthalene, 1-hydroxy-5-aminonaphthalene, 1-hydroxy-4-aminonaphthalene, 2-hydroxy-7-aminonaphthalene, 2-hydroxy-6-aminonaphthalene, 2-hydroxy-5-aminonaphthalene, 1-carboxy-7-aminonaphthalene, 1-carboxy-6-aminonaphthalene, 1-carboxy-5-aminonaphthalene, and 2-carboxy-7-aminonaphthalene. , 2-carboxy-6-aminonaphthalene, 2-carboxy-5-aminonaphthalene, 2-aminobenzoic acid, 3-aminobenzoic acid, 4-aminobenzoic acid, 4-aminosalicylic acid, 5-aminosalicylic acid, 6-aminosalicylic acid, 2-aminobenzenesulfonic acid, 3-aminobenzenesulfonic acid, 4-aminobenzenesulfonic acid, 3-amino-4,6-dihydroxypyrimidine, 2-aminophenol, 3-aminophenol, 4-aminophenol, 2-aminothiophenol, 3-aminothiophenol, 4-aminothiophenol, 2-amino-4-tert-butylphenol, etc. can be used. Among these, aniline, 2-ethynylaniline, 3-ethynylaniline, 4-ethynylaniline, and 2-amino-4-tert-butylphenol are preferred. Two or more of these may be used.

[0043]

[0044] In formula (1), R １ represents a monovalent organic group having 1 to 20 carbon atoms, and * represents the point of attachment to a dicarboxylic acid residue, tricarboxylic acid residue, or tetracarboxylic acid residue.

[0045] In formula (2), R ２represents a monovalent organic group having 1 to 20 carbon atoms, and * represents the point of attachment to a dicarboxylic acid residue, tricarboxylic acid residue, or tetracarboxylic acid residue.

[0046] Examples of monovalent organic groups having 1 to 20 carbon atoms include branched or linear alkyl groups, alkylene groups, and alkyne groups, all of which have a total carbon number of 1 to 20, and also include those in which some of the hydrogen atoms in these groups have been substituted with oxyalkyl groups, thioalkyl groups, cyano groups, or halogen groups.

[0047] The photosensitive resin composition of the present invention is preferably such that the difference (Ra(2) - Ra(1)) between the surface roughness (Ra(1)) of a resin film obtained by applying the photosensitive resin composition to a substrate and heat-treating it at 120°C for 3 minutes and the surface roughness (Ra(2)) of a film obtained by treating the resin film with a 2.38 mass% aqueous solution of tetramethylammonium hydroxide (aqueous solution of TMAH) at 23°C for 1 minute is 10 nm or more and 200 nm or less.

[0048] By being in this range, the difference in local alkali solubility during development is small, pattern opening properties with high in-plane uniformity can be obtained, and clouding after development can be suppressed. From this viewpoint, (Ra(2) - Ra(1)) is more preferably 20 to 100 nm, and even more preferably 30 to 50 nm.

[0049] Furthermore, in the photosensitive resin composition of the present invention, the difference (θ(1)) between the static contact angle of water on the surface of a resin film obtained by applying the photosensitive resin composition to a substrate and heat-treating it at 120°C for 3 minutes and the static contact angle of water on the surface of a film obtained by treating the resin film with a 2.38 mass% aqueous TMAH solution at 23°C for 1 minute (θ(2)) is preferably 5° or more and less than 30°, more preferably 5° or more and less than 20°.

[0050] By being in this range, the difference in partial alkali solubility during development is small, pattern opening properties with high in-plane uniformity can be obtained, and cloudiness after development can be suppressed. Furthermore, the difference (θa(1)-θa(2)) between the advancing contact angle of water (θa(1)) on the film before treatment with a TMAH aqueous solution and the advancing contact angle (θa(2)) on the surface of the film after treating the resin film with a TMAH aqueous solution for 1 minute is preferably 5° or more and less than 20°, and more preferably 5° or more and less than 15°. Furthermore, the difference (θr(1)-θr(2)) between the receding contact angle of water (θr(1)) on the surface of the film after treating the resin film with a TMAH aqueous solution for 1 minute is preferably 10° to 60°, and more preferably 20° to 35°. By being in this range, the difference in partial alkali solubility during development is small, pattern opening properties with high in-plane uniformity can be obtained, and cloudiness after development can be suppressed.

[0051] In addition, the ratio (R(B) / R(A)) of the alkaline dissolution rate (R(A)) of the resin (A) used in the photosensitive resin composition of the present invention to the alkaline dissolution rate (R(B)) of the resin (B) is preferably 2.5 to 30. This range makes it easy to realize the phase-separated structure, and the difference in surface roughness (Ra(2)-Ra(1)) and the difference in contact angle (θ(1)-θ(2)), (θa(1)-θa(2)), (θr(1)-θr(2)) can be set within preferred ranges. This results in high opening properties when an opening pattern is formed by exposure, development, and curing, and also excellent pattern uniformity, and can suppress cloudiness after development. It is more preferable that (R(B) / R(A)) is 4.0 to 15.

[0052] In the photosensitive resin composition of the present invention, the resin (A) has carboxyl groups and esterified carboxyl groups, and the ratio of the esterified carboxyl groups to the total amount of carboxyl groups and esterified carboxyl groups (100 mol%) is preferably 50 to 80 mol%, more preferably 60 to 75 mol%. This range allows the alkali dissolution rate of the resin A to be within a preferred range, and the difference in surface roughness (Ra(2)-Ra(1)) and the difference in contact angle (θ(1)-θ(2)), (θa(1)-θa(2)), and (θr(1)-θr(2)) to be within preferred ranges. This results in high opening properties when an opening pattern is formed by exposure, development, and curing, and also excellent pattern uniformity, and suppresses cloudiness after development. An example of a method for obtaining an esterified carboxyl group is a method in which, when polymerizing a resin, a diluted solution of an esterifying agent such as N,N-dimethylformamide dimethyl acetal, N,N-dimethylformamide diethyl acetal, or N,N-dimethylacetamide dimethyl acetal is added dropwise to a resin solution having a carboxyl group.

[0053] The photosensitive resin composition of the present invention contains a photosensitizer. A quinone diazide compound is preferably used as the photosensitizer. By containing a quinone diazide compound in the photosensitive resin composition of the present invention, an acid is generated in the ultraviolet-exposed area, and the solubility of the exposed area in an alkaline aqueous solution is increased. Therefore, a positive pattern can be obtained by alkaline development after ultraviolet exposure.

[0054] The content of the photosensitizer used in the present invention is preferably 1 part by mass or more, more preferably 3 parts by mass or more, relative to 100 parts by mass of the resin (A) from the viewpoint of increasing sensitivity, and is preferably 30 parts by mass or less, more preferably 20 parts by mass or less, from the viewpoint of maintaining the mechanical properties of the cured film. Furthermore, a sensitizer and the like may be contained as necessary.

[0055] Examples of quinone diazide compounds include those in which the sulfonic acid of quinone diazide is ester-bonded to a polyhydroxy compound, those in which the sulfonic acid of quinone diazide is sulfonamide-bonded to a polyamino compound, and those in which the sulfonic acid of quinone diazide is ester-bonded and / or sulfonamide-bonded to a polyhydroxypolyamino compound. While not all functional groups of these polyhydroxy compounds or polyamino compounds need to be substituted with quinone diazide, it is preferred that 50 mol% or more of the total functional groups be substituted with quinone diazide. By using such quinone diazide compounds, a positive photosensitive resin composition can be obtained that is sensitive to common ultraviolet rays, such as the i-line (365 nm), h-line (405 nm), and g-line (436 nm) of a mercury lamp.

[0056] In the present invention, the quinone diazide compound preferably has either a 5-naphthoquinone diazide sulfonyl group or a 4-naphthoquinone diazide sulfonyl group. A compound having both of these groups in the same molecule may be used, or compounds having different groups may be used in combination.

[0057] Two or more quinone diazide compounds may be contained, which can increase the ratio of the dissolution rate of the exposed area to the dissolution rate of the unexposed area, thereby obtaining a highly sensitive positive photosensitive resin composition.

[0058] As the quinone diazide compound, the compound represented by the following formula is particularly preferred.

[0059]

[0060] In formula (3), Q is a structure represented by formula (4) or a hydrogen atom, and in formula (4), * represents the point of attachment to the structure of formula (3).

[0061] When the total amount of Q is taken as 100 mol%, it is preferable that the structure represented by formula (4) is 90 to 100 mol%. Furthermore, of the total amount of 100 mol% of the quinone diazide compound of formula (3), when the molar ratio of those in which all of Q are hydrogen atoms is a(0), the molar ratio of those in which one of Q is a structure represented by formula (4) is a(1), the molar ratio of those in which two of Q are structures represented by formula (4) is a(2), and the molar ratio of those in which all of Q are structures represented by formula (4) is a(3), it is preferable that a(0) is 0 to 15 mol%, a(1) is 0 to 5 mol%, a(2) is 10 to 20 mol%, and a(3) is 80 to 90 mol%. By being in this range, the difference in partial alkali solubility during development is small, the opening property when an opening pattern is formed by exposure, development, and curing is high, and the pattern uniformity is also excellent, and cloudiness after development can be suppressed.

[0062] The quinone diazide compound used in the present invention can be synthesized by a known method, for example, by reacting 5-naphthoquinone diazide sulfonyl chloride with a polyhydroxy compound in the presence of triethylamine.

[0063] The photosensitive resin composition of the present invention is applied to a substrate and heat-treated to give a resin film that exhibits a phase-separated structure.

[0064] The photosensitive resin composition of the present invention preferably further contains a compound represented by any one of formulas (5) to (10) (hereinafter, sometimes referred to as "compound (C)").

[0065]

[0066] In formula (5), R ３ represents a hydrogen atom, a hydroxyl group, or a monovalent organic group having 1 to 10 carbon atoms; R ４ and R ５ each independently represents a hydrogen atom or a monovalent organic group having 1 to 10 carbon atoms; R ６ and R ７ each independently represents a monovalent organic group having 1 to 4 carbon atoms.

[0067] In formula (6), R ８ represents a monovalent organic group having 1 to 6 carbon atoms, and R９ and R １０ each independently represents a monovalent organic group having 1 to 4 carbon atoms.

[0068] In formula (7), R １１ and R １２ each independently represents a monovalent organic group having 1 to 10 carbon atoms.

[0069] In formula (8), R １３ From R １６ each independently represents a monovalent organic group having 1 to 4 carbon atoms.

[0070] In formula (9), R １７ and R １８ each independently represents a monovalent organic group having 1 to 4 carbon atoms; and m is 1 or 2.

[0071] In formula (10), R １９ and R ２０ each independently represents a monovalent organic group having 1 to 4 carbon atoms.

[0072] In the above formulas (5) to (10), examples of the monovalent organic group include branched or linear alkyl groups, alkylene groups, and alkyne groups, each having a total carbon number within the range indicated for each group, and also includes groups in which some of the hydrogen atoms in these groups have been substituted with oxyalkyl groups, thioalkyl groups, cyano groups, or halogen groups.

[0073] The inclusion of compound (C) in the photosensitive resin composition of the present invention improves the storage stability of the photosensitive resin composition, stabilizes the size of the phase-separated structure in the photosensitive resin composition against changes over time, and provides a resin film obtained by coating and heat-treating the composition, in which the continuous phase in the phase-separated structure has high uniformity, i.e., the width of the continuous phase is small and has little variation in width when a cross-sectional photograph is taken. The content of compound (C) is preferably 0.1 to 1 mass% when the total mass of the photosensitive resin composition is taken as 100 mass%, or preferably 0.1 to 1 mass% when the total mass of resin (A), resin (B), and compound (C) is taken as 100 mass%. A content of 0.1 parts by mass or more is advantageous in terms of the effect of stabilizing the size of the phase-separated structure against changes over time, while a content of 1 part by mass or less suppresses excessive increases in the alkali solubility of unexposed portions of the photosensitive resin composition after the exposure step, thereby achieving highly uniform pattern opening properties within the surface and suppressing cloudiness after development.

[0074] Examples of the compound represented by formula (5) include, but are not limited to, N,N-dimethylpropanamide, N,N-dimethylisobutyramide, N,N-dimethylbutanamide, 2-methyl-N,N-dimethylbutanamide, N,N-dimethylpentanamide, N,N-dimethylisobutyramide, 2-methoxy-N,N-dimethylethanamide, 2-ethoxy-N,N-dimethylethanamide, 2-propoxy-N,N-dimethylethanamide, and 2-butoxy-N,N-dimethylethanamide.

[0075] Examples of the compound represented by formula (6) include, but are not limited to, 3-methoxy-N,N-dimethylpropanamide, 3-ethoxy-N,N-dimethylpropanamide, 3-propoxy-N,N-dimethylpropanamide, 3-butoxy-N,N-dimethylpropanamide, 3-methoxy-N,N-diethylpropanamide, and 3-methoxy-N,N-dipropylpropanamide.

[0076] Examples of the compound represented by formula (7) include, but are not limited to, 3-methoxy-3-methylbutyl acetate and 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate.

[0077] Examples of the compound represented by formula (8) include, but are not limited to, N,N,N',N'-tetramethylurea, N,N,N',N'-tetraethylurea, and N,N-diethyl-N',N'-dimethylurea.

[0078] Examples of the compound represented by formula (9) include, but are not limited to, N,N-dimethylpropylene urea, N,N-diethylpropylene urea, N,N-dipropylpropylene urea, 1,3-dimethyl-2-imidazolidinone, 1,3-diethyl-2-imidazolidinone, and 1,3-dipropyl-2-imidazolidinone.

[0079] Examples of the compound represented by formula (10) include, but are not limited to, methyl ethyl ketone, methyl propyl ketone, methyl isobutyl ketone, and diisobutyl ketone.

[0080] The photosensitive resin composition of the present invention may contain a thermal crosslinking agent as needed. Examples of thermal crosslinking agents that are preferably used include, but are not limited to, compounds having at least two alkoxymethyl groups and / or methylol groups, and compounds having at least two epoxy groups and / or oxetanyl groups. By including these compounds, a condensation reaction occurs with the resin (A) during the curing treatment after pattern processing, forming a crosslinked structure, improving the mechanical properties of the cured film. Two or more types of thermal crosslinking agents may also be used, allowing for a wider range of design possibilities.

[0081] Preferred examples of compounds having at least two alkoxymethyl groups and / or methylol groups include DML-PC, DML-PEP, DML-OC, DML-OEP, DML-34X, DML-PTBP, DML-PCHP, DML-OCHP, DML-PFP, DML-PSBP, DML-POP, DML-MBOC, DML-MBPC, DML-MTrisPC, DML-BisOC-Z, DML-BisOCHP-Z, DML-BPC, DML-BisOC-P, and DMOM-P. C, DMOM-PTBP, DMOM-MBPC, TriML-P, TriML-35XL, TML-HQ, TML-BP, TML-pp-BPF, TML-BPE, TML-BPA, TML-BPAF, TML-BPAP, TMOM-BP, TMOM-BPE, TMOM-BPA, TMOM-BPAF, TMOM-BPAP, HML-TPPHBA, HML-TPHAP, HMOM-TPPHBA, HMOM-TPHAP (all trade names, manufactured by Honshu Chemical Industry Co., Ltd.), "NIKALAC" (registered trademark) Examples of such compounds include NIKALAC MX-290, NIKALAC MX-280, NIKALAC MX-270, NIKALAC MX-279, NIKALAC MW-100LM, and NIKALAC MX-750LM (all of which are trade names manufactured by Sanwa Chemical Co., Ltd.), and these compounds are available from the respective companies. Two or more of these compounds may be used in combination.

[0082] Furthermore, preferred examples of the compound having at least two epoxy groups and / or oxetanyl groups include, but are not limited to, bisphenol A epoxy resins, bisphenol A oxetanyl resins, bisphenol F epoxy resins, bisphenol F oxetanyl resins, propylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, and epoxy group-containing silicones such as polymethyl(glycidyloxypropyl)siloxane. Specifically, "EPICLON" (registered trademark) 850-S, EPICLON HP-4032, EPICLON HP-7200, EPICLON HP-820, EPICLON HP-4700, EPICLON EXA-4710, EPICLON HP-4770, EPICLON EXA-859CRP, EPICLON EXA-1514, EPICLON EXA-4880, EPICLON EXA-4850-150, EPICLON EXA-4850-1000, EPICLON EXA-4816, EPICLON Examples of such resins include EXA-4822 (trade names, manufactured by Dainippon Ink and Chemicals, Inc.), "RIKARESIN" (registered trademark) BEO-60E (trade name, manufactured by New Japan Chemical Co., Ltd.), EP-4003S, and EP-4000S (trade names, manufactured by ADEKA Corporation), which are available from various companies. Two or more of these may be used.

[0083] The content of the thermal crosslinking agent used in the present invention is preferably 0.5 parts by mass or more, more preferably 1 part by mass or more, and even more preferably 10 parts by mass or more, relative to 100 parts by mass of the resin (A). From the viewpoint of maintaining mechanical properties such as elongation, the content is preferably 300 parts by mass or less, more preferably 200 parts by mass or less.

[0084] The photosensitive resin composition of the present invention may contain a solvent, if necessary. Preferred examples of the solvent include polar aprotic solvents such as N-methyl-2-pyrrolidone, γ-butyrolactone, N,N-dimethylformamide, N,N-dimethylacetamide, and dimethyl sulfoxide; ethers such as tetrahydrofuran, dioxane, propylene glycol monomethyl ether, and propylene glycol monoethyl ether; ketones such as acetone, methyl ethyl ketone, and diisobutyl ketone; esters such as ethyl acetate, butyl acetate, isobutyl acetate, propyl acetate, propylene glycol monomethyl ether acetate, and 3-methyl-3-methoxybutyl acetate; alcohols such as ethyl lactate, methyl lactate, diacetone alcohol, and 3-methyl-3-methoxybutanol; and aromatic hydrocarbons such as toluene and xylene. The photosensitive resin composition may contain two or more of these solvents.

[0085] The content of the solvent is preferably 70 parts by mass or more, more preferably 100 parts by mass or more, relative to 100 parts by mass of the resin (A) from the viewpoint of dissolving the resin, and is preferably 1,800 parts by mass or less, more preferably 1,500 parts by mass or less, from the viewpoint of obtaining an appropriate film thickness.

[0086] The photosensitive resin composition of the present invention may contain a low molecular weight compound having a phenolic hydroxyl group, if necessary. By containing a low molecular weight compound having a phenolic hydroxyl group, it becomes easier to adjust the alkali solubility during pattern processing.

[0087] The content of the low molecular weight compound having a phenolic hydroxyl group is preferably 0.1 parts by mass or more, more preferably 1 part by mass or more, per 100 parts by mass of resin (A), and from the viewpoint of maintaining mechanical properties such as elongation, is preferably 30 parts by mass or less, more preferably 15 parts by mass or less.

[0088] The photosensitive resin composition of the present invention may contain, as needed, surfactants, esters such as ethyl lactate and propylene glycol monomethyl ether acetate, alcohols such as ethanol, ketones such as cyclohexanone and methyl isobutyl ketone, and ethers such as tetrahydrofuran and dioxane, in order to improve wettability with the substrate. Some of these may also serve as solvents.

[0089] The content of the compound used for the purpose of improving the wettability with the substrate is preferably 0.001 parts by mass or more relative to 100 parts by mass of the resin (A), and from the viewpoint of obtaining an appropriate film thickness, is preferably 1,800 parts by mass or less, more preferably 1,500 parts by mass or less.

[0090] In addition, in order to enhance adhesion to the silicon substrate, a silane coupling agent such as trimethoxyaminopropylsilane, trimethoxyepoxysilane, trimethoxyvinylsilane, or trimethoxythiolpropylsilane may be contained.

[0091] The content of the compound used to enhance adhesion to the silicon substrate is preferably 0.01 parts by mass or more per 100 parts by mass of the resin (A), and from the viewpoint of maintaining mechanical properties such as elongation, is preferably 5 parts by mass or less.

[0092] The viscosity of the photosensitive resin composition of the present invention is preferably 2 to 5,000 mPa·s. By adjusting the solid content concentration so that the viscosity is 2 mPa·s or more, it becomes easy to obtain a desired film thickness. On the other hand, if the viscosity is 5,000 mPa·s or less, it becomes easy to obtain a highly uniform coating film. A photosensitive resin composition having such a viscosity can be easily obtained, for example, by adjusting the solid content concentration to 5 to 60 mass%.

[0093] Next, a method for forming a cured film using the photosensitive resin composition of the present invention will be described.

[0094] The photosensitive resin composition of the present invention is applied to a substrate. Examples of substrates that can be used include, but are not limited to, wafers of silicon, ceramics, gallium arsenide, or the like, or substrates on which metals are formed as electrodes or wiring. Application methods include spin coating using a spinner, spray coating, and roll coating. The coating thickness varies depending on the application technique, the solids concentration of the composition, the viscosity, and other factors, but the composition is typically applied so that the film thickness after drying is 0.5 to 20 μm.

[0095] The substrate coated with the photosensitive resin composition is then heat-treated (pre-baked) to obtain a resin film of the photosensitive resin composition. Pre-baking is preferably performed using a hot plate at a temperature of 80 to 150°C for 1 to 30 minutes, or at 100 to 130°C for 1 to 5 minutes.

[0096] When a resin pattern is formed using this photosensitive resin composition, the film of this photosensitive resin composition is then exposed to actinic rays through a mask having a desired pattern. Actinic rays used for exposure include ultraviolet rays, visible light, electron beams, and X-rays, but in the present invention, i-rays (365 nm), h-rays (405 nm), and g-rays (436 nm) from a mercury lamp are preferably used.

[0097] The exposure may be performed using a half-tone mask, or by performing multiple exposures with different exposure locations, masks, and exposure amounts, so that the exposure amount varies depending on the exposure location on the substrate.

[0098] After exposure, the film is developed using a developer. Preferred developer solutions include aqueous solutions of alkaline compounds 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, and hexamethylenediamine. In some cases, polar solvents such as N-methyl-2-pyrrolidone, N,N-dimethylformamide, N,N-dimethylacetamide, dimethylsulfoxide, γ-butyrolactone, and dimethylacrylamide, alcohols such as methanol, ethanol, and isopropanol, esters such as ethyl lactate and propylene glycol monomethyl ether acetate, and ketones such as cyclopentanone, cyclohexanone, isobutyl ketone, and methyl isobutyl ketone may be added to these alkaline aqueous solutions, either singly or in combination. After development, the film is preferably rinsed with water. Here too, rinsing treatment may be carried out by adding alcohols such as ethanol and isopropyl alcohol, or esters such as ethyl lactate and propylene glycol monomethyl ether acetate to water.

[0099] After pre-baking, or after forming a resin pattern by the above-mentioned method, it is preferable to apply a temperature of 150 to 400°C to promote thermal crosslinking, imide ring-closing reaction, and oxazole ring-closing reaction to harden the film, thereby improving the heat resistance and chemical resistance of the cured film. This heat treatment (cure) is preferably carried out by selecting a temperature and increasing the temperature stepwise, or by selecting a temperature range and increasing the temperature continuously for 30 minutes to 3 hours.

[0100] When the surface roughness of the cured film is Ra(3) and the surface roughness of a film obtained by subjecting the cured film to oxygen plasma treatment is Ra(4), the difference between them (Ra(4) - Ra(3)) is preferably 10 nm or more and 200 nm or less. The oxygen plasma treatment is carried out using a plasma etching device under the following conditions: gas type: oxygen, gas pressure: 20 Pa, gas flow rate: 100 sccm, power: 200 W, time: 60 seconds, and temperature: 25°C. When (Ra(4) - Ra(3)) is in this range, pattern opening properties with high in-plane uniformity can be obtained, and clouding of the film surface due to plasma treatment can be suppressed. It is more preferable that (Ra(4) - Ra(3)) is 10 nm or more and 50 nm or less, and even more preferable that it is 10 nm or more and 30 nm or less.

[0101] The cured film formed from the photosensitive resin composition of the present invention is suitably used for applications such as a passivation film for semiconductors, a protective film for semiconductor elements, an interlayer insulating film for multilayer wiring for high-density packaging, and an insulating layer for organic electroluminescent elements.

[0102] The present invention will be described below with reference to examples, but the present invention should not be construed as being limited to these examples. First, the evaluation method will be described. In the evaluation of the photosensitive resin composition (hereinafter sometimes referred to as "varnish"), the composition was filtered in advance through a 1 μm polytetrafluoroethylene filter.

[0103] (1) Film Thickness Measurement The film thickness of the resin film on the substrate was measured using an optical interference film thickness measuring device (Lambda Ace VM-1030 manufactured by Dainippon Screen Mfg. Co., Ltd.). The refractive index was set to 1.629.

[0104] (2) Measurement of Alkaline Dissolution Rate of Resin A resin was dissolved in γ-butyrolactone (GBL) at a solids concentration of 35% by mass, and the solution was applied to a 6-inch silicon wafer and prebaked on a hot plate at 120°C for 4 minutes to form a prebaked film with a film thickness of 10 μm±0.5 μm. This was then immersed in a 2.38% by mass aqueous solution of tetramethylammonium hydroxide at 23°C for 1 minute, and the dissolved film thickness was calculated from the film thickness before and after immersion, and the film thickness dissolved per minute was taken as the alkaline dissolution rate. Note that when the resin film completely dissolved in less than 1 minute, the time required for dissolution was measured, and the film thickness calculated from this and the film thickness before immersion was used to calculate the film thickness dissolved per minute, which was taken as the alkaline dissolution rate of the resin.

[0105] (3) Measurement of Weight Average Molecular Weight Using a gel permeation chromatography (GPC) apparatus (Waters 2690-996 manufactured by Japan Waters K.K.), the resin was measured using N-methyl-2-pyrrolidone (NMP) as a developing solvent, and the weight average molecular weight (Mw) was calculated in terms of polystyrene.

[0106] (4) Measurement of esterification rate The resin was dissolved in deuterated dimethyl sulfoxide. １ The esterification rate (%) was measured using H NMR. The integral value of the peak at around 3.8 ppm was defined as x when the integral value of the peaks of all aromatic compounds from 6.0 to 9.0 ppm was taken as 100, the amount of hydrogen in the ester group when a unit weight (for example, 1 g) of the resin was completely esterified was defined as z, and the number of aromatic ring hydrogen atoms contained in the same weight of resin was defined as y. The esterification rate (%) was calculated as {(x / 100)÷(z / y)}×100.

[0107] (5) Evaluation of Pattern Processability The varnish was applied to an 8-inch silicon wafer by spin coating using a coater / developer (ACT-8 manufactured by Tokyo Electron Limited), and then prebaked at 120°C for 3 minutes to form a prebaked film (resin film) with a film thickness of 6 to 8 μm. A mask having a 5 μm-wide line and space pattern was set in an i-line stepper exposure machine (NSR-2005i9C manufactured by Nikon Corporation), and the prebaked film was exposed to 10 to 500 mJ / cm. ２ at an exposure dose of 10 mJ / cm ２The wafer was exposed to light in steps. After exposure, an ACT-8 developing device was used, and a 2.38% by mass aqueous solution of tetramethylammonium hydroxide was used. Development was performed twice using the puddle method, with the developer ejection time being 5 seconds and the puddle time being 35 seconds. The wafer was then rinsed with pure water and dried, yielding a developed film. The silicon wafer with the developed film was cured in a clean oven (CLH-21CD-S, manufactured by Koyo Thermo Systems Co., Ltd.) at 150°C for 30 minutes under a nitrogen stream (oxygen concentration 20 ppm or less), and then further heated to 320°C for 1 hour. When the temperature reached 50°C or less, the silicon wafer was removed and a cured film (hardened film) was obtained.

[0108] The minimum exposure dose (Eth) at which a 5 μm wide pattern opens is 10 mJ / cm ２ More than 100mJ / cm ２ A is less than 100 mJ / cm ２ 150mJ / cm or more ２ B is less than 150 mJ / cm ２ More than 200mJ / cm ２ C, and 200 mJ / cm ２ The above was rated D.

[0109] (6) Evaluation of in-plane uniformity of pattern (5) The minimum exposure dose at which the pattern opened was 50 mJ / cm ２ The above was added to obtain the exposure dose used in this evaluation (evaluation exposure dose), and the same procedure as in (5) was followed, except that the exposure dose was fixed to the evaluation exposure dose, and nine points, namely, ±80 mm from the wafer center, ±60 mm from the wafer center, ±40 mm from the wafer center, ±20 mm from the wafer center, and the wafer center, were exposed to light for pattern processing, to obtain a cured film (hardened film).

[0110] The opening dimensions of the pattern in the 5 μm wide line and space portion were measured in the direction perpendicular to the lines using a digital microscope, and the range (maximum value - minimum value) of the opening dimensions at nine points was determined. The opening dimension range was rated A for less than 0.07 μm, B for 0.07 μm or more but less than 0.1 μm, C for 0.1 μm or more but less than 0.5 μm, and D for 0.5 μm or more.

[0111] (7) Evaluation of Phase Separation 1 A 100 nm-thick thin film sample was sampled from the prebaked film obtained in (5) using a focused ion beam (FIB) processing and observation device (Hitachi High-Tech FB-2000), and the cross section of the film was observed at an accelerating voltage of 200 kV using a transmission electron microscope (JEOL JEM-F200). A 2 μm square area was cut out from the obtained image, and the observed image was converted to 16-bit using the image analysis software "ImageJ", after which the image was smoothed. At this time, a Gaussian filter σ = 2.0 was used. Next, the image background was subtracted. A rolling ball radius = 30 pixels. Next, the image contrast was enhanced. The number of saturated pixels = 0.35%. Next, a threshold was set using IsoData Auto, and the area ratio of the colored area to the entire image was calculated as the phase separation area ratio. Those with an area ratio of 30 to 50% were designated A, those excluding A and with an area ratio of 20 to 70% were designated B, and the rest were designated C.

[0112] Regarding the developed film obtained in (5), those without any opacity in the unexposed area were rated as A, those with slight opacity were rated as B, and those with obvious opacity were rated as C.

[0113] (8) Evaluation of Phase Separation 2 (Slope a) A 2 μm square region was cut out from the image obtained in (7), and the image was converted to 32-bit using the image analysis software "ImageJ." Noise was reduced using a Gaussian filter σ = 2.0, and background subtraction was performed using a Rolling Ball radius = 30 pixels. Next, the image was binarized using the Default threshold determination algorithm. For areas recognized as black foreground (among these, units in which one phase is surrounded by other parts in the image are considered "island domains"), the area value of the island domain to be analyzed was set to "100 pixels^2 - Infinity," and the sum of brightness (IntDen) was calculated. However, island domains that are not entirely visible in the image were excluded. A scatter diagram of the analysis results was plotted with the area of ​​the island domains (Area) on the X axis and the sum of the luminance (IntDen) on the Y axis, and a linear approximation curve of the plot was drawn, with the slope being designated as slope a.

[0114] The slope a was rated as A when it was between -2.0 and -5.0, B when it was between -1.5 and -10.0 excluding A, C when it was between -1.0 and -30.0 excluding A and B, and D otherwise.

[0115] (9) Surface Roughness Evaluation 1 (Ra(2)-Ra(1)) Using an AFM (Dimension Icon manufactured by Bruker), the measurement range was 500 nm square, the aspect ratio was 2.00, and the measurement speed was 1.00 Hz, and the height difference of the resin film surface obtained in (5) was measured, and the difference between the maximum height and the minimum height was taken as the surface roughness Ra(1). Similarly, the surface roughness of the developed film surface obtained in (5) was taken as Ra(2), and (Ra(2)-Ra(1)) was calculated.

[0116] Those having (Ra(2)-Ra(1)) of 30 to 50 nm were designated as A, those excluding A and having 20 to 100 nm were designated as B, and those excluding A and B and having 10 to 200 nm were designated as C.

[0117] (10) Evaluation of Contact Angle The static water contact angle θ(1), advancing contact angle θa(1), and receding contact angle θr(1) were measured for the prebaked film obtained in (5). The static water contact angle θ(2), advancing contact angle θa(2), and receding contact angle θr(2) were also measured for the developed film. (θ(1) - θ(2)) was rated A when it was 5° or more and less than 20°, B when it was 20° or more and less than 30°, and C when it was 30° or more. There were no other values. (θa(1) - θa(2)) was rated A when it was 5° or more and less than 15°, B when it was 15° or more and less than 20°, and C when it was 20° or more. There were no other values. (θr(1) - θr(2)) was rated A when it was 20° to 35°, B when it was 10° to 60° except for A, and C when it was otherwise.

[0118] (11) Evaluation of Phase Separation 3 The phase separation area ratio was calculated in the same manner as in "(7) Evaluation of Phase Separation 1", except that the cured film obtained in (5) was used instead of the prebaked film obtained in (5). The area ratio of 30 to 50% was rated as A, the area ratio of 20 to 70% except for A was rated as B, and the rest was C.

[0119] (12) Surface Roughness Evaluation 2 (Ra(4)-Ra(3)) For the cured film obtained in (5), the surface roughness (Ra(3)) was determined using the same method as described in "(9) Surface Roughness Evaluation 1". Next, the cured film was treated using a plasma etching device (device name) under the following conditions: gas type: oxygen, gas pressure: 20 Pa, gas flow rate: 100 sccm, power: 200 W, time: 60 seconds, temperature: 25°C, and the surface roughness (Ra(4)) after treatment was measured. Those with (Ra(4)-Ra(3)) of 10 to 30 nm were rated A, those with 10 to 50 nm other than A were rated B, and all others were rated C.

[0120] Synthesis Example 1 Synthesis of Diamine Compound 1 164.8 g (0.45 mol) of 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane (BAHF) was dissolved in 900 mL of acetone and 156.8 g (2.7 mol) of propylene oxide, and the solution was cooled to −15° C. To this solution, a solution of 183.7 g (0.99 mol) of 3-nitrobenzoyl chloride dissolved in 900 mL of acetone was added dropwise. After completion of the dropwise addition, the mixture was reacted 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.

[0121] 270 g of the solid was placed in a 3 L stainless steel autoclave and dispersed in 2400 mL of methyl cellosolve, and 5 g of 5% palladium-carbon was added. Hydrogen was introduced into the autoclave using a balloon, and the reduction reaction was carried out at room temperature. After 2 hours, the reaction was terminated after confirming that the balloon no longer deflated. After the reaction was completed, the palladium compound catalyst was removed by filtration, and the mixture was concentrated using a rotary evaporator to obtain diamine compound 1 represented by the following formula:

[0122]

[0123] Synthesis Example 2 Synthesis of Resin (A-1) Under a dry nitrogen stream, 62.04 g (0.20 mol) of bis(3,4-dicarboxyphenyl)ether dianhydride (ODPA) was dissolved in 630 g of NMP. To this solution, 96.72 g (0.16 mol) of diamine compound 1 and 2.49 g (0.01 mol) of 1,3-bis(3-aminopropyl)tetramethyldisiloxane were added along with 20 g of NMP, and the mixture was allowed to react at 20°C for 1 hour, followed by a reaction at 50°C for 2 hours. Next, 4.69 g (0.04 mol) of 4-ethynylaniline as an end-capping agent was added along with 10 g of NMP, and the mixture was allowed to react at 50°C for 2 hours. Thereafter, a solution prepared by diluting 38.13 g (0.32 mol) of N,N-dimethylformamide dimethyl acetal with 80 g of NMP was added dropwise over 10 minutes. After the dropwise addition, the mixture was stirred at 50°C for 3 hours. After stirring, the solution was cooled to room temperature and then poured into 5 L of water to obtain a precipitate. The 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 resin (A-1).

[0124] Synthesis Example 3 Synthesis of Resin (A-2) Resin (A-2) powder was obtained in the same manner as in Synthesis Example 2, except that the amount of N,N-dimethylformamide dimethyl acetal was 40.51 g (0.34 mol).

[0125] Synthesis Example 4 Synthesis of Resin (A-3) Resin (A-3) powder was obtained in the same manner as in Synthesis Example 2, except that the amount of N,N-dimethylformamide dimethyl acetal was 44.09 g (0.37 mol).

[0126] Synthesis Example 5 Synthesis of Resin (A-4) A powder of Resin (A-4) was obtained in the same manner as in Synthesis Example 2, except that the amount of Diamine Compound 1 was 99.14 g (0.164 mol) and the amount of N,N-dimethylformamide dimethyl acetal was 40.51 g (0.34 mol).

[0127] Synthesis Example 6 Synthesis of Resin (A-5) A powder of Resin (A-5) was obtained in the same manner as in Synthesis Example 2, except that the amount of Diamine Compound 1 was 102.77 g (0.17 mol) and the amount of N,N-dimethylformamide dimethyl acetal was 40.51 g (0.34 mol).

[0128] Synthesis Example 7 Synthesis of Resin (A-6) Resin (A-6) powder was obtained in the same manner as in Synthesis Example 2, except that 4-ethynylaniline was replaced with 4.37 g (0.04 mol) of 3-aminophenol and the amount of N,N-dimethylformamide dimethyl acetal was changed to 35.75 g (0.30 mol).

[0129] Synthesis Example 8 Synthesis of Resin (A-7) Resin (A-7) powder was obtained in the same manner as in Synthesis Example 2, except that the amount of 4-ethynylaniline and 3-aminophenol was 4.37 g (0.04 mol) and the amount of N,N-dimethylformamide dimethyl acetal was 47.66 g (0.40 mol).

[0130] Synthesis Example 9 Synthesis of Resin (A-8) Resin (A-8) powder was obtained in the same manner as in Synthesis Example 2, except that the amount of 4-ethynylaniline and 3-aminophenol was 4.37 g (0.04 mol) and the amount of N,N-dimethylformamide dimethyl acetal was 52.43 g (0.44 mol).

[0131] Synthesis Example 10 Synthesis of Resin (A-9) Resin (A-9) powder was obtained in the same manner as in Synthesis Example 2, except that the amount of 4-ethynylaniline and 4-aminophenol was 4.37 g (0.04 mol) and the amount of N,N-dimethylformamide dimethyl acetal was 47.66 g (0.40 mol).

[0132] Synthesis Example 11 Synthesis of Resin (A-10) Resin (A-10) powder was obtained in the same manner as in Synthesis Example 2, except that the amount of 4-ethynylaniline and 2-amino-4-tert-butylphenol was 6.61 g (0.04 mol) and the amount of N,N-dimethylformamide dimethyl acetal was 40.51 g (0.34 mol).

[0133] Synthesis Example 12 Synthesis of Resin (A-11) Under a dry nitrogen stream, 61.53 g (0.168 mol) of BAHF, 2.49 g (0.01 mol) of 1,3-bis(3-aminopropyl)tetramethyldisiloxane, and 4.37 g (0.04 mol) of 3-aminophenol as an end-capping agent were dissolved in 730 g of NMP. 62.04 g (0.20 mol) of ODPA was added to the solution along with 20 g of NMP, and the mixture was reacted at 20°C for 1 hour, and then at 50°C for 4 hours. The mixture was then stirred at 190°C for 5 hours. After stirring, the solution was cooled to room temperature and then poured into 5 L of water to obtain a precipitate. The 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 Resin (A-11).

[0134] [Synthesis Example 13] Synthesis of Resin (B-1) Under a dry nitrogen stream, 75.70 g (0.7 mol) of m-cresol, 21.63 g (0.2 mol) of p-cresol, 12.22 g (0.1 mol) of 2,5-dimethylphenol, 75.5 g of a 37% by mass aqueous formaldehyde solution (0.93 mol of formaldehyde), 0.63 g (0.005 mol) of oxalic acid dihydrate, and 260 g of methyl isobutyl ketone were charged, and the mixture was immersed in an oil bath and refluxed for 4 hours to carry out a polycondensation reaction. Thereafter, the temperature of the oil bath was raised over 3 hours, and then the pressure in the flask was reduced to 40 to 67 hPa, the volatiles were removed, and the dissolved resin was cooled to room temperature to obtain a polymer solid of Resin (B-1).

[0135] Synthesis Example 14 Synthesis of Resin (B-2) A polymer solid of Resin (B-2) was obtained by the same synthesis as in Synthesis Example 13, except that the amounts of m-cresol, p-cresol, and 2,5-dimethylphenol in Synthesis Example 13 were changed to 64.88 g (0.6 mol) of m-cresol, 32.44 g (0.3 mol) of p-cresol, and 12.22 g (0.1 mol) of 2,5-dimethylphenol, respectively.

[0136] Synthesis Example 15 Synthesis of Resin (B-3) A polymer solid of Resin (B-3) was obtained in the same manner as in Synthesis Example 13, except that the amounts of m-cresol, p-cresol, and 2,5-dimethylphenol in Synthesis Example 13 were changed to 32.44 g (0.3 mol) of m-cresol and 75.70 g (0.7 mol) of p-cresol, respectively.

[0137] [Synthesis Example 16] Synthesis of Resin (B-4) 2400 g of tetrahydrofuran, a mixed solution containing 2.56 g (0.04 mol) of sec-butyllithium as an initiator, was added with 95.18 g (0.54 mol) of p-t-butoxystyrene and 6.25 g (0.06 mol) of styrene, and the mixture was stirred for 3 hours. After polymerization, 12.82 g (0.4 mol) of methanol was added to terminate the polymerization. The reaction mixture was then poured into 3 L of methanol to purify the polymer, the precipitated polymer was dried, and further dissolved in 1.6 L of acetone. 2 g of concentrated hydrochloric acid was added at 60 ° C. and stirred for 7 hours. The polymer was then precipitated by pouring into water. The p-t-butoxystyrene was deprotected and converted to hydroxystyrene, and the mixture was washed three times with water. After drying for 24 hours in a vacuum dryer at 50 ° C., resin (B-4) was obtained.

[0138] Synthesis Example 17 Synthesis of Quinone Diazide Compound 1 Under a dry nitrogen stream, 42.45 g (0.1 mol) of TrisP-PA (trade name, manufactured by Honshu Chemical Industry Co., Ltd.) and 75.23 g (0.28 mol) of 5-naphthoquinone diazide sulfonyl chloride (NAC-5, manufactured by Toyo Gosei Co., Ltd.) were dissolved in 1,000 g of 1,4-dioxane. While the reaction vessel was ice-cooled, a mixture of 150 g of 1,4-dioxane and 30.36 g (0.3 mol) of triethylamine was added dropwise so that the temperature in the system did not exceed 35°C. After the dropwise addition, the mixture was stirred at 30°C for 2 hours. The triethylamine salt was filtered, and the filtrate was poured into 7 L of pure water to obtain a precipitate. This precipitate was collected by filtration and further washed with 2 L of 1% by mass hydrochloric acid. Thereafter, it was further washed twice with 5 L of pure water. This precipitate was dried in a vacuum dryer at 50° C. for 24 hours to obtain a quinone diazide compound 1 represented by the following formula in which an average of 2.8 of Q had been converted to 5-naphthoquinone diazide sulfonate.

[0139]

[0140] In formula (3), Q １ and Q ２ and Q ３ is a structure represented by formula (4) or a hydrogen atom, １ From the H NMR spectrum, Q out of the total amount of quinone diazide compounds (100 mol%) １ and Q ２ and Q ３ The molar ratio a(0) of all hydrogen atoms is 0%, Q １ and Q ２ and Q ３ One of the structures represented by formula (4) has a molar ratio a(1) of 0%, and Q １ and Q ２ and Q ３ Two of the structures represented by formula (4) have a molar ratio a(2) of 15%, and Q １ and Q ２ and Q ３ All of the compounds had the structure represented by formula (4), and the molar ratio a(3) was 85%.

[0141] Synthesis Example 18 Synthesis of quinone diazide compound 2

[0123] A quinone diazide compound 2 represented by formula (3) in which an average of 2.6 Q's had been converted to 5-naphthoquinone diazide sulfonate was obtained in the same manner as in Synthesis Example 17, except that 69.86 g (0.26 mol) of 5-naphthoquinone diazide sulfonyl chloride was used.

[0142] １ From the H NMR spectrum, Q out of the total amount of quinone diazide compounds (100 mol%) １ and Q ２ and Q ３ The molar ratio a(0) of all hydrogen atoms is 0%, Q １ and Q ２ and Q ３ One of the structures represented by formula (4) has a molar ratio a(1) of 5%, and Q １ and Q ２ and Q ３ Two of the structures represented by formula (4) have a molar ratio a(2) of 29%, and Q １ and Q ２ and Q ３ ​All of the compounds had the structure represented by formula (4), and the molar ratio a(3) was 66%.

[0143] The alkali dissolution rates and weight average molecular weights of the alkali-soluble resins (A-1 to A-11, B-1 to B-4) obtained in Synthesis Examples 2 to 16, which were determined by the above-mentioned methods, are shown in Table 1. For A-1 to A-11, the esterification rates and the SP values ​​of the monoamines used as end-capping agents are also shown in Table 1.

[0144]

[0145] Examples 1 to 31, Comparative Examples 1 to 6 Resin (A), resin (B), and compound (C) were blended as shown in Table 2, and 1.4 g of quinone diazide compound 1 or quinone diazide compound 2 obtained in Synthesis Example 17 or 18, 1.1 g of Nikalac MX-270 (trade name, manufactured by Sanwa Chemical Co., Ltd.), and 17.1 g of GBL were added and stirred to obtain varnishes 1 to 37. The blending amounts and blending ratios of resin (A) and resin (B), the alkali dissolution rate ratio (R(B) / R(A)), and the weight average molecular weight ratio (Mw(A) / Mw(B)) are shown in Table 2, and the results of the evaluations (5) to (12) above are shown in Table 3.

[0146] The abbreviations of the materials used are as follows: MPA: 3-methoxy-N,N-dimethylpropanamide DMPA: N,N-dimethylpropanamide TMU: N,N,N',N'-tetramethylurea DMI: 1,3-dimethyl-2-imidazolidinone

[0147]

[0148]

[0149]

[0150]

Claims

1. A photosensitive resin composition containing at least a resin selected from the group consisting of polyimide, polybenzoxazole, polyamide, and precursors thereof and copolymers thereof (hereinafter, such a resin may be referred to as "resin (A)"), a resin selected from the group consisting of phenolic resin and polyhydroxystyrene (hereinafter, such a resin may be referred to as "resin (B)"), and a photosensitizer, wherein the photosensitive resin composition is applied to a substrate and heat-treated to obtain a resin film that exhibits a phase-separated structure.

2. The photosensitive resin composition according to claim 1, wherein the surface roughness of a resin film obtained by applying the photosensitive resin composition to a substrate and heating it at 120°C for 3 minutes is Ra(1), and the surface roughness of the film obtained after treating the resin film with a 2.38 mass% aqueous solution of tetramethylammonium hydroxide at 23°C for 1 minute is Ra(2), and the difference between these (Ra(2) - Ra(1)) is 10 nm or more and 200 nm or less.

3. The photosensitive resin composition according to claim 1 or 2, further comprising a compound represented by any one of formulas (5) to (10) (hereinafter sometimes referred to as "compound (C)"), wherein the content of compound (C) is 0.1 to 1 mass % when the total mass of the photosensitive resin composition is 100 mass %. (R ３ represents a hydrogen atom, a hydroxyl group, or a monovalent organic group having 1 to 10 carbon atoms; R ４ and R ５ each independently represents a hydrogen atom or a monovalent organic group having 1 to 10 carbon atoms; R ６ , R ７ , R ９ , R １０ and R １３ From R ２０ each independently represents a monovalent organic group having 1 to 4 carbon atoms; R ８ represents a monovalent organic group having 1 to 6 carbon atoms, and R １１ and R １２ each independently represents a monovalent organic group having 1 to 10 carbon atoms, and m is 1 or 2.

4. The photosensitive resin composition according to claim 1 or 2, wherein the static contact angle of water on the surface of a resin film obtained by applying the photosensitive resin composition to a substrate and heating it at 120°C for 3 minutes is θ(1), and the static contact angle of water on the surface of the film after treating the resin film with a 2.38 mass% aqueous solution of tetramethylammonium hydroxide at 23°C for 1 minute is θ(2), and the difference between these (θ(1) - θ(2)) is 5° or more and less than 30°.

5. The photosensitive resin composition according to claim 1 or 2, wherein Mw(A) is the weight average molecular weight of resin (A) and Mw(B) is the weight average molecular weight of resin (B), Mw(A) is 10,000 to 40,000, and Mw(A) / Mw(B) is 1 to 20.

6. The photosensitive resin composition according to claim 1 or 2, wherein all or part of the carboxyl group terminals of resin (A) have a structure of formula (1) or formula (2), and the solubility parameter (SP value) of the amine that reacts with the carboxyl group terminals to give the structure of formula (1) or formula (2) is 8.0 to 16.

0. (In formula (1), R １ represents a monovalent organic group having 1 to 20 carbon atoms, and * represents the point of attachment to a dicarboxylic acid residue, a tricarboxylic acid residue, or a tetracarboxylic acid residue. ２ represents a monovalent organic group having 1 to 20 carbon atoms, and * represents the point of attachment to a dicarboxylic acid residue, tricarboxylic acid residue, or tetracarboxylic acid residue.) 7. The photosensitive resin composition according to claim 1 or 2, wherein R(A) (nm / min) is the dissolution rate of resin (A) in a 2.38 mass% aqueous solution of tetramethylammonium hydroxide at 23°C, and R(B) (nm / min) is the dissolution rate of resin (B) in a 2.38 mass% aqueous solution of tetramethylammonium hydroxide at 23°C, R(A) is 500 to 5000 nm / min, and R(B) / R(A) is 2.5 to 30.

8. The photosensitive resin composition according to claim 1 or 2, wherein the resin (A) has carboxyl groups and esterified carboxyl groups in its molecular structure, and the proportion of the esterified carboxyl groups is 50 to 80 mol % when the total amount of carboxyl groups and esterified carboxyl groups is 100 mol %.

9. The photosensitive resin composition according to claim 5, wherein the Mw(A) / Mw(B) is 7 to 10.

10. The photosensitive resin composition according to claim 1 or 2, wherein the phase-separated structure of the resin film obtained by applying the photosensitive resin composition to a substrate and heat-treating it is such that, when an image of a cross section of the resin film is analyzed under the following conditions, one phase occupies 30 to 50% of the area of ​​the entire image. <Image Analysis Conditions> The cross section of the heat-treated resin film is observed using a transmission electron microscope, and a 2 μm square region is cut out from the obtained image. The image is converted to 16 bits using the image analysis software "ImageJ," and then smoothed. A Gaussian filter of σ = 2.0 is used. Next, the image background is subtracted. The rolling ball radius is 30 pixels. Next, the image contrast is enhanced. The number of saturated pixels is 0.35%. Next, the image is binarized by setting a threshold value using IsoData Auto, and the area ratio of the colored area to the entire image is calculated.

11. A cured film obtained by curing the photosensitive resin composition according to claim 1 or 2.

12. The cured film according to claim 11, wherein the surface roughness of the cured film according to claim 11 is Ra(3) and the surface roughness of a film obtained by treating the cured film with oxygen plasma is Ra(4), and the difference between the surface roughnesses (Ra(4) - Ra(3)) is 10 nm or more and 200 nm or less.

13. The cured film according to claim 11, wherein, when an image of a cross section of the cured film is analyzed under the following conditions, one phase occupies 30 to 50% of the area of ​​the entire image. <Image analysis conditions> A cross section of the cured film was observed using a transmission electron microscope, and a 2 μm square region was cut out from the obtained image. The image was converted to 16 bits using image analysis software "ImageJ" and then smoothed using a Gaussian filter σ=2.

0. Next, the background of the image is subtracted. The rolling ball radius at this time is set to 30 pixels. Next, the contrast of the image is enhanced. The number of saturated pixels at this time is set to 0.35%. Next, the image is binarized by setting a threshold value with IsoData Auto, and the area ratio of the colored area to the entire image is calculated.

14. An interlayer insulating film using the cured film according to claim 11.

15. A semiconductor protective film using the cured film according to claim 11.

Images