Positive photosensitive resin composition, insulating resin film, method of forming insulating resin film, and semiconductor device

Abstract

A positive photosensitive resin composition according to the present invention comprises: (A) an alkali-soluble resin which has a phenolic hydroxyl group and an imide group; (B) a photoacid generator; and (C) a thermal crosslinking agent. The photoacid generator contains an o-quinone diazide compound represented by formula (I). Therein, Q is a group represented by formula (3a) or the like.

Description

Positive photosensitive resin composition, insulating resin film, method for forming insulating resin film, and semiconductor device

[0001] The present disclosure relates to a positive photosensitive resin composition, an insulating resin film having a pattern including openings, a method for forming an insulating resin film having a pattern including openings, and a semiconductor device.

[0002] Patent Document 1 discloses a positive photosensitive resin composition containing an alkali-soluble resin having an imide bond and a phenolic hydroxyl group as a material capable of forming a surface protective layer or an interlayer insulating layer of a semiconductor element.

[0003] International Publication No. 2021 / 261448

[0004] The present disclosure relates to a positive photosensitive resin composition that can form an insulating resin film having a well-defined pattern with high resolution.

[0005] The present disclosure includes the following: [1] A photo-acid generator comprising: (A) an alkali-soluble resin having a phenolic hydroxyl group and an imide group; (B) a photoacid generator which is a compound that generates an acid by light; and (C) a thermal crosslinker which is a compound that crosslinks the alkali-soluble resin by heat, wherein the photoacid generator is represented by the following formula (I): R １ is an alkanediyl group having 1 to 3 carbon atoms, and R ２ is an alkyl group having 1 to 3 carbon atoms, p is an integer of 0 to 4, and multiple R ２ may be the same or different, and Q is represented by the following formula (3a), (3b) or (3c): [2] A positive photosensitive resin composition, wherein the alkali-soluble resin is a group represented by the following formula (II): and R ３ is a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and Z １[3] The positive photosensitive resin composition according to [1], wherein the thermal crosslinking agent contains an alkoxy compound having a plurality of alkoxy groups. [4] The positive photosensitive resin composition according to [1] or [2], wherein a portion of a 5 μm-thick photosensitive layer containing the positive photosensitive resin composition, which corresponds to a through-hole having a width of 5 to 20 μm, is exposed to light, and the exposed photosensitive layer is heated to 1000 mJ / m ２ The positive photosensitive resin composition according to any one of [1] to [3], wherein when the photosensitive layer is developed under conditions in which the through-holes are formed using an aqueous tetramethylammonium hydroxide solution having a concentration of 2.38 mass % at an exposure dose of 1000 nm, the remaining film thickness of the photosensitive layer is 95% or more of the film thickness of the photosensitive layer before exposure. [5] A method for forming an insulating resin film, comprising: exposing a part of a photosensitive layer containing the positive photosensitive resin composition according to any one of [1] to [4]; forming an insulating resin film having a pattern including openings by development that removes part of the photosensitive layer; and heating the insulating resin film. [6] An insulating resin film having a pattern including openings, comprising a cured product of the positive photosensitive resin composition according to any one of [1] to [4]. [7] A semiconductor device comprising: a semiconductor chip; and a wiring portion including a conductor wiring layer connected to the semiconductor chip and one or more insulating layers, wherein at least a part of the one or more insulating layers is the insulating resin film according to [6].

[0006] A positive photosensitive resin composition can be provided that can form an insulating resin film having a well-defined pattern with high resolution.

[0007] 1 is a flowchart showing an example of a method for forming an insulating resin film having a pattern.

[0008] The present invention is not limited to the following examples. In this disclosure, the term "process" includes not only an independent process but also a process that cannot be clearly distinguished from other processes as long as the intended function of the process is achieved. The term "layer" encompasses not only a structure that is formed over the entire surface when observed in a plan view, but also a structure that is formed only on a portion of the surface. Numerical ranges indicated using "to" indicate ranges that include the numerical values ​​before and after "to" as the minimum and maximum values, respectively. In numerical ranges described in stages in this specification, the upper or lower limit of a numerical range of a certain stage may be replaced with the upper or lower limit of a numerical range of another stage. In numerical ranges described in this specification, the upper or lower limit of the numerical range may be replaced with the value shown in the examples.

[0009] Photosensitive Resin Composition An example of a photosensitive resin composition includes (A) an alkali-soluble resin having a phenolic hydroxyl group and an imide group, (B) a photoacid generator that generates an acid when exposed to light, and (C) a thermal crosslinker that crosslinks the alkali-soluble resin when exposed to heat. The photosensitive resin composition according to the present disclosure can function as a positive-type photosensitive resin composition based on a change in solubility in an alkaline developer due to exposure to light. Furthermore, a film containing the photosensitive resin composition according to the present disclosure can be thermally cured mainly by a crosslinking reaction between the thermal crosslinker and the alkali-soluble resin to form an insulating resin film that is a cured film containing a cured product of the photosensitive resin composition.

[0010] (A) Alkali-Soluble Resin The alkali-soluble resin may be a polymer having a structural unit having a phenolic hydroxyl group and an imide group. The alkali-soluble resin may have a cyclic imide group containing an imide group and a hydrocarbon group that forms a cyclic structure together with the imide group. The cyclic imide group may be a five-membered ring. The alkali-soluble resin may contain an aromatic group, an alicyclic group, or both that form a condensed ring with the cyclic imide group.

[0011] The alkali-soluble resin having a cyclic imide group may be, for example, a polymer containing a structural unit which is a group obtained by removing one or more hydrogen atoms from a bisphenolimide compound represented by the following formula (II): ３is a hydrogen atom or an alkyl group having 1 to 3 carbon atoms (for example, a methyl group), and Z １ is a tetravalent organic group. The alkali-soluble resin having a structural unit derived from a bisphenolimide compound represented by formula (II) may be a novolak resin containing a structural unit derived from a bisphenolimide compound represented by formula (II).

[0012] Z １ may be one cyclic hydrocarbon group which may have a substituent (for example, an alkyl group having 1 to 3 carbon atoms), or a group having two or more cyclic hydrocarbon groups which may have a substituent (for example, an alkyl group having 1 to 3 carbon atoms) and a divalent organic group or a covalent bond bonding them together.

[0013] Z １ Examples of the cyclic hydrocarbon group include groups in which one or more hydrogen atoms have been removed from the following cyclic hydrocarbon compounds:

[0014] Z １ The divalent organic group linking the two cyclic hydrocarbon groups may be, for example, a divalent group selected from an oxy group (-O-), a thio group (-S-), a carbonyl group, an alkylene group having 1 to 3 carbon atoms, a phenylene group, an alkylphenylene group, and groups consisting of combinations thereof. Examples of the alkylene group having 1 to 3 carbon atoms include a methylene group, an ethylene group, an ethylidene group, a propane-1,3-diyl group, a propane-1,1-diyl group, and a propane-2,2-diyl group. Z １ Specific examples of the divalent organic group linking two cyclic hydrocarbon groups include alkylene groups having 1 to 3 carbon atoms as well as the following:

[0015] In these formulas, R １０ represents an alkyl group having 1 to 3 carbon atoms (e.g., a methyl group), and multiple R １０ may be the same or different. q represents an integer of 0 to 4, and multiple q's in one formula may be the same or different. R １１ represents an alkylene group (e.g., propane-2,2-diyl group, methylene group), an oxy group, a thio group, or a direct bond. １２represents an alkylene group (for example, an ethane-1,2-diyl group).

[0016] The bisphenolimide compound may be a compound represented by the following formula (IIA), (IIB), or (IIC): ３ is R in formula (II) ３ R in formula (IIB) is defined as ４ represents a direct bond (covalent bond) or a divalent organic group. ４ Examples of divalent organic groups as １ The divalent organic group bonding two cyclic hydrocarbon groups includes the same as the examples given in formula (IIC). ５ represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms (for example, a methyl group).

[0017] Formula (IIB) may be, for example, the following formula (IIB'): ３ and R ４ is R in formula (IIB) ３ and R ４ is defined similarly.

[0018] In the bisphenolimide compound represented by formula (IIA), (IIB), or (IIB'), from the viewpoint of improving solubility in solvents, at least one of the two phenolic hydroxyl groups may be bonded to the meta- or ortho-position relative to the imide group. Examples of the bisphenolimide compound represented by formula (IIA) in which the phenolic hydroxyl group is bonded to the meta- or ortho-position relative to the imide group include compounds represented by formulas (IIA-1), (IIA-2), (IIA-3), or (IIA-4) below. Examples of the bisphenolimide compound represented by formula (IIB) in which the phenolic hydroxyl group is bonded to the meta- or ortho-position relative to the imide group include compounds represented by formulas (IIB-1), (IIB-2), (IIB-3), or (IIB-4) below. These compounds tend to have an excellent balance between solubility and mechanical strength. R in formulas (IIB-1), (IIB-2), (IIB-3), and (IIB-4) ４is R in formula (IIB). ４ is defined similarly.

[0019] The novolak resin containing a structural unit derived from a bisphenolimide compound represented by formula (II) may have a polymer chain in which structural units derived from a phenolic compound selected from phenol, o-cresol, m-cresol, and p-cresol or a bisphenolimide compound are alternately bonded with structural units derived from a reactive compound selected from an aldehyde compound, a compound having multiple methoxymethyl groups, and a compound having multiple hydroxymethyl groups. The structural unit derived from a bisphenolimide compound may be a residue in which one or more hydrogen atoms have been removed from an aromatic group (particularly a benzene ring to which a phenolic hydroxyl group is bonded) in the bisphenolimide compound. The structural unit derived from the bisphenolimide compound may be bonded to another structural unit at the ortho- or para-position relative to the phenolic hydroxyl group.

[0020] The aldehyde compound constituting the novolac resin may be formaldehyde. The compound having multiple methoxymethyl groups may be a compound having an aromatic ring (e.g., a benzene ring) to which methoxymethyl groups are bonded. The compound having multiple hydroxymethyl groups may be a compound having an aromatic ring (e.g., a benzene ring) to which hydroxymethyl groups are bonded. Examples of compounds having multiple methoxymethyl groups include compounds represented by the following formula (21) or (22). In these formulas, R １０ represents an alkyl group having 1 to 3 carbon atoms (e.g., a methyl group). １０ may be the same or different. p represents an integer of 0 to 4, and q and r each independently represent an integer of 0 to 4. The compound having multiple methoxymethyl groups may be bis(methoxymethyl)biphenyl, dimethoxymethylbenzene, or a combination thereof. An example of a compound having multiple hydroxymethyl groups includes 2,6-bis(hydroxymethyl)-p-cresol.

[0021] The residue derived from formaldehyde is usually a methylene group. The residue derived from a compound having two or more methoxymethyl groups can be, for example, a divalent group represented by the following formula (21A) or (22B). R in formula (21A) and (22B) １０ , p, q and r are R in formulas (21) and (22). １０ , p, q and r are defined similarly.

[0022] In the phenolic compounds that react with aldehyde compounds or the like in the reaction to produce the novolac resin, the proportion of the bisphenolimide compound may be 10 mol% or more and 100 mol% or less, 20 mol% or more and 100 mol% or less, 30 mol% or more and 100 mol% or less, or 40 mol% or more and 100 mol% or less, based on the total amount of the phenolic compounds. A high proportion of the bisphenolimide compound is likely to provide particularly excellent effects in terms of a good shape and high resolution of the insulating resin film. From the same perspective, the proportion of the bisphenolimide compound may be 50 mol% or more, 60 mol% or more, 70 mol% or more, 80 mol% or more, or 90 mol% or more, based on the total amount of the phenolic compounds, or may be substantially 100 mol%.

[0023] The novolac resin, which is an alkali-soluble resin, can be synthesized, for example, by a method similar to the method for synthesizing a general phenol novolac resin or cresol novolac resin.

[0024] The weight average molecular weight (Mw) of the alkali-soluble resin may be 1,000 to 500,000, 2,000 to 400,000, 3,000 to 350,000, or 5,000 to 300,000, from the viewpoint of the balance between solubility in an alkaline aqueous solution, photosensitive properties, and mechanical strength of the insulating resin film. In the present disclosure, the weight average molecular weight is a converted value measured by gel permeation chromatography (GPC) using a standard polystyrene calibration curve.

[0025] (B) Photoacid Generator The photoacid generator is a compound represented by the following formula (I): In formula (I), R １ is an alkanediyl group having 1 to 3 carbon atoms, and R２ is an alkyl group having 1 to 3 carbon atoms, p is an integer of 0 to 4, and multiple R ２ may be the same or different. Q in formula (I) is a group represented by the following formula (3a), (3b), or (3c), or a hydrogen atom. Multiple Qs in the same molecule may be the same or different, and at least one of the multiple Qs in the same molecule is a group represented by formula (3a), (3b), or (3c). R ２ may be a methyl group. p may be 0 to 3, 0 to 2, 0 to 1, or 0. Two or more, or three or more of the four Qs in the same molecule may be groups represented by formula (3a), (3b), or (3c).

[0026] The combination of an alkali-soluble resin having a phenolic hydroxyl group and an imide group with an o-quinonediazide compound represented by formula (I) can contribute to the formation of an insulating resin film having a well-shaped pattern with high resolution.

[0027] The o-quinonediazide compound represented by (I) may be a compound represented by the following formula (IA): ２ , Q and p are R in formula (I). ２ , Q and p are defined similarly.

[0028] The photoacid generator may further contain a compound other than the o-quinonediazide compound represented by formula (I). The proportion of the o-quinonediazide compound represented by formula (I) in the photoacid generator may be 50% by mass or more, 60% by mass or more, 70% by mass or more, 80% by mass or more, or 90% by mass or more but 100% by mass or less, or may be substantially 100% by mass.

[0029] From the viewpoint of good sensitivity, the content of the photoacid generator or the o-quinonediazide compound represented by formula (I) may be 1 to 50 mass %, 3 to 35 mass %, or 5 to 20 mass % relative to the content of the alkali-soluble resin of the component (A).

[0030] (C) Thermal Crosslinking Agent The thermal crosslinking agent of component (C) contains one or more compounds that crosslink the alkali-soluble resin by heat. The compound constituting the thermal crosslinking agent may have multiple functional groups that can react with the alkali-soluble resin and bond to the molecular chain of the alkali-soluble resin. Examples of such functional groups include alkoxy groups, epoxy groups, and oxazoline groups. The thermal crosslinking agent may contain an alkoxy compound having multiple alkoxy groups.

[0031] The alkoxy compound that can be used as a thermal crosslinking agent is thought to function as a thermal crosslinking agent that crosslinks molecular chains of an alkali-soluble resin mainly through a reaction between an aromatic group (phenylene group) to which a phenolic hydroxyl group is bonded and an alkoxy group. The number of alkoxy groups in the alkoxy compound may be 2 or more, 3 or more, or 4 or more, and may be 20 or less, 15 or less, or 10 or less.

[0032] At least a portion of the two or more alkoxy groups of the alkoxy compound may be methoxy groups. In other words, the alkoxy compound may have multiple methoxy groups. The alkoxy compound may have four or more methoxy groups.

[0033] The alkoxy compound may have a cyclic group obtained by removing one or more hydrogen atoms from benzene, 1,3,5-triazine, glycoluril, 2-imidazolidinone, or urea, and an alkoxyalkyl group (e.g., a methoxymethyl group or a 1,3-dimethoxypropan-2-yl group) may be bonded to the cyclic group. An alkoxy compound having a cyclic group (benzene ring) obtained by removing a hydrogen atom from benzene may have a phenolic hydroxyl group bonded to the cyclic group. In the present disclosure, a compound having an alkoxy group and a phenolic hydroxyl group may be considered a thermal crosslinking agent for component (C) rather than an alkali-soluble resin. An alkoxy compound having an alkoxy group and a phenolic hydroxyl group may contribute to improving the sensitivity of the photosensitive resin composition.

[0034] The weight average molecular weight of the alkoxy compound may be 3000 or less, 2000 or less, or 1500 or less, or may be 100 or more, from the viewpoint of the balance of solubility in an alkaline developer, photosensitive properties, and mechanical strength.

[0035] Specific examples of alkoxy compounds having a phenolic hydroxyl group include compounds represented by the following formula (41), (42), (43), (44), (45), or (46). Specific examples of alkoxy compounds having a cyclic group formed by removing one or more hydrogen atoms from 1,3,5-triazine, glycoluril, 2-imidazolidinone, or urea include compounds represented by the following formula (47), (48), (49), or (50).

[0036] In formulas (41) to (50), R ４０ represents an alkoxyalkyl group, and multiple R ４０ may be the same or different. ４０ may be a methoxyalkyl group or a dimethoxyalkyl group, an example of which is a methoxymethyl group (-CH ２ OCH ３ ), and a 1,3-dimethoxypropan-2-yl group represented by the following formula:

[0037] From the viewpoints of heat resistance of the insulating resin film (cured film) and suppression of warpage, the content of the thermal crosslinking agent (or alkoxy compound) may be 1 to 70 mass %, 2 to 50 mass %, or 3 to 40 mass % relative to the content of the alkali-soluble resin of the component (A).

[0038] In the photosensitive resin composition, the total content of the (A) alkali-soluble resin, the (B) photoacid generator, and the (C) thermal crosslinking agent may be 50% by mass or more, 60% by mass or more, 70% by mass or more, 80% by mass or more, 90% by mass or more, or 95% by mass or more, based on the amount of the photosensitive resin composition. When the photosensitive resin composition contains a solvent, the amount of the photosensitive resin composition herein is the amount excluding the solvent.

[0039] Other Components In addition to components (A) to (C), the photosensitive resin composition may further contain other components such as an elastomer, an adhesion aid, a solvent, a compound that generates an acid upon heating, a dissolution promoter, a dissolution inhibitor, a Cu rust inhibitor, a coupling agent, a surfactant, and a leveling agent. The photosensitive resin composition may further contain, in addition to component (A), an alkali-soluble resin that does not fall under component (A).

[0040] The elastomer may be, for example, one or more selected from styrene-based elastomers, olefin-based elastomers, urethane-based elastomers, polyester-based elastomers, polyamide-based elastomers, acrylic-based elastomers, and silicone-based elastomers.

[0041] The elastomer may be an acrylic elastomer containing a (meth)acrylic acid alkyl ester as a monomer unit. The (meth)acrylic acid alkyl ester may have an alkyl group having 1 to 20 carbon atoms. The acrylic elastomer may further contain, as a monomer unit, one or more acrylic monomers selected from (meth)acrylic acid, an aliphatic alcohol and ester having an amino group, a (meth)acrylic acid alkyl ester having a hydroxyalkyl group having 4 to 20 carbon atoms, and (meth)acrylic acid. The content of the elastomer may be 0 to 50 mass%, 0.5 to 50 mass%, 1 to 30 mass%, or 2 to 20 mass% relative to the amount of the alkali-soluble resin. "(Meth)acrylic acid" means acrylic acid or methacrylic acid.

[0042] The adhesion promoter may include a nitrogen-containing aromatic compound, examples of which include 1H-tetrazole, 5-aminotetrazole, 5-phenyltetrazole, and 5-methyltetrazole. The content of the adhesion promoter may be 0 to 20 mass%, 0.01 to 20 mass%, 0.015 to 10 mass%, or 0.02 to 7 mass% relative to the content of the alkali-soluble resin of component (A).

[0043] Examples of solvents include γ-butyrolactone, ethyl lactate, propylene glycol monomethyl ether acetate, benzyl acetate, n-butyl acetate, ethoxyethyl propionate, 3-methylmethoxypropionate, N-methyl-2-pyrrolidone, N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide, hexamethylphosphorylamide, tetramethylene sulfone, diethyl ketone, diisobutyl ketone, methyl amyl ketone, cyclohexanone, propylene glycol monomethyl ether, propylene glycol monopropyl ether, propylene glycol monobutyl ether, and dipropylene glycol monomethyl ether. These solvents can be used alone or in combination of two or more. The solvent may include ethyl lactate, γ-butyrolactone, or a combination thereof. In a photosensitive resin composition containing a solvent, the concentration of components other than the solvent (solid content) may be 1 to 80% by mass based on the mass of the photosensitive resin composition containing the solvent.

[0044] The compound that generates an acid upon heating promotes the thermal crosslinking reaction between the alkali-soluble resin and the oxazoline compound or alkoxy compound, which can result in further improved heat resistance of the cured film. The compound that generates an acid upon heating can also contribute to improved resolution. Examples of the compound that generates an acid upon heating include salts formed from a strong acid and a base, such as onium salts, and imide sulfonates. The content of the compound that generates an acid upon heating may be 0 to 30% by mass, 0.1 to 30% by mass, 0.2 to 20% by mass, or 0.5 to 10% by mass relative to the content of the alkali-soluble resin of component (A).

[0045] The dissolution promoter is a component that increases the dissolution rate of the exposed area in a developer, and can contribute to improving sensitivity and resolution. The dissolution promoter may include a compound having a carboxy group, a sulfo group, or a sulfonamide group. The content of the dissolution promoter may be 0 to 30% by mass, or 0.01 to 30% by mass, relative to the content of the alkali-soluble resin of component (A).

[0046] The dissolution inhibitor is a compound that inhibits the dissolution of exposed areas in an alkaline aqueous solution and is used to control the film thickness, development time, and contrast after development. Examples of dissolution inhibitors include diphenyliodonium nitrate, bis(p-tert-butylphenyl)iodonium nitrate, diphenyliodonium bromide, diphenyliodonium chloride, and diphenyliodonium iodide. The content of the dissolution inhibitor may be 0 to 20% by mass, 0.01 to 20% by mass, 0.01 to 15% by mass, or 0.05 to 10% by mass relative to the content of the alkali-soluble resin of component (A).

[0047] The coupling agent may include an organic silane compound (silane coupling agent), an aluminum chelate compound, or a combination thereof. Examples of commercially available organic silane compounds include KBM-403, KBM-803, and KBM-903 (trade names, manufactured by Shin-Etsu Chemical Co., Ltd.). The content of the coupling agent may be 0 to 20% by mass, 0.1 to 20% by mass, or 0.5 to 10% by mass relative to the content of the alkali-soluble resin of component (A).

[0048] Examples of surfactants or leveling agents include polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl ether, and polyoxyethylene octylphenol ether. Examples of commercially available products include Megafac F-171, F-565, and RS-78 (trade names, manufactured by DIC Corporation). The content of the surfactant or leveling agent may be 0 to 5 mass%, 0.001 to 5 mass%, or 0.01 to 3 mass%, relative to the content of the alkali-soluble resin of component (A).

[0049]

[0023] Method for forming an insulating resin film having a pattern including openings can be formed by photolithography using the photosensitive resin composition according to the present disclosure. Fig. 1 is a flowchart showing an example of a method for forming an insulating resin film having a pattern including openings. The method shown in Fig. 1 includes a step S1 of forming a photosensitive layer including the photosensitive resin composition, a step S2 of exposing a portion of the photosensitive layer to light, a step S3 of removing a portion of the photosensitive layer through development to form an insulating resin film having a pattern including openings, and a step S4 of heating the insulating resin film.

[0050] The photosensitive layer containing the photosensitive resin composition can be applied to, for example, a glass substrate, a semiconductor substrate, a metal oxide insulating substrate (e.g., TiO ２ , SiO ２ The photosensitive layer may be formed on any substrate, such as a silicon nitride substrate. The photosensitive layer may be formed, for example, by a method including coating a solvent-containing positive photosensitive resin composition on the substrate and removing the solvent from the coating. The coating may be heated to remove the solvent. The thickness of the photosensitive layer may be 0.1 to 40 μm.

[0051] A portion of the photosensitive layer is exposed by irradiation with actinic rays through a mask. The actinic rays may be ultraviolet light, visible light, or radioactive rays, and may be g-rays, h-rays, i-rays, or a combination thereof.

[0052] By developing to remove a portion of the photosensitive layer, a resin film (insulating resin film) having a pattern including openings is formed. A developer may be used for the development. Examples of development using a developer include shower development, spray development, immersion development, and puddle development. The resin film (insulating resin film) after development may be washed with water or the like.

[0053] The developer may be an alkaline aqueous solution. The alkaline aqueous solution may contain one or more bases selected from sodium carbonate, sodium hydroxide, potassium hydroxide, sodium silicate, ammonia, ethylamine, diethylamine, triethylamine, triethanolamine, and tetramethylammonium hydroxide (TMAH). The concentration of the base in the alkaline aqueous solution may be 0.1 to 10% by mass based on the mass of the alkaline aqueous solution. The developer may contain alcohol or a surfactant.

[0054] The photosensitive layer containing the photosensitive resin composition and having a thickness of 5 μm was exposed to light in the areas corresponding to the through holes having a width of 5 to 20 μm. ２ When the photosensitive layer is developed under conditions in which through-holes are formed using an aqueous tetramethylammonium hydroxide solution having a concentration of 2.38 mass % at an exposure dose of 1000 nm, the remaining film thickness of the photosensitive layer may be 95% or more of the film thickness of the photosensitive layer before exposure.

[0055] By heating the resin film (insulating resin film) that is the photosensitive layer remaining after development, an insulating resin film that is a resin film containing a thermoset product of the photosensitive resin composition is formed mainly by a reaction between the alkali-soluble resin and the thermal crosslinking agent. The heating temperature may be 300°C or less, 270°C or less, or 250°C or less, or may be 160°C or more. The heating time may be, for example, 0.5 hours or more and 5 hours or less.

[0056] The resin film (insulating resin film) can be heated using a heating device such as a quartz tube furnace, a hot plate, a rapid thermal annealer, a vertical diffusion furnace, an infrared curing furnace, an electron beam curing furnace, a microwave curing furnace, a microwave curing device, a frequency-variable microwave curing device, etc. The heating atmosphere may be, for example, an air atmosphere or an inert gas atmosphere containing nitrogen or the like.

[0057] The insulating resin film may be, for example, an insulating layer constituting a wiring portion of a semiconductor device. The semiconductor device may have a semiconductor chip, a conductor wiring layer connected to the semiconductor chip, and a wiring portion (rewiring portion) including one or more insulating layers, and at least a portion of the one or more wiring layers may be an insulating resin film including a cured product of the photosensitive resin composition according to the present disclosure.

[0058] FIG. 2 is a partial cross-sectional view showing an example of a semiconductor device having an insulating layer. The semiconductor device 100 shown in FIG. 2 includes a semiconductor chip 10 and a wiring section 20 provided on the semiconductor chip 10. The wiring section 20 includes a conductor wiring layer 31 connected to the semiconductor chip 10, a surface protective layer 41, a cover coat layer 42, and conductive balls 50. The semiconductor device 100 may be a semiconductor package having a wafer-level package (WLP) configuration. The surface protective layer 41 and the cover coat layer 42 are stacked in this order from the semiconductor chip 10 side, and the conductive balls 50 are provided outside the cover coat layer 42. The surface protective layer 41 and the cover coat layer 42 are insulating layers, and one or both of them may be an insulating resin film containing a cured product of the photosensitive resin composition according to the present disclosure.

[0059] The semiconductor chip 10 has a chip main body 11 having a circuit surface, pads 12 provided on the circuit surface of the chip main body 11, and a protective film 13 having a pattern including openings through which the pads 12 are exposed. The conductor wiring layer 31 of the wiring section 20 is a rewiring layer connected to the pads 12 and extends to the inside of the conductive balls 50 between a surface protective layer 41 and a cover coat layer 42. A connection section 32 for connecting to the conductive balls 50 is provided on an end of the conductor wiring layer 31. A barrier metal 33 is provided between the connection section 32 and the conductive balls 50. The pads 12, conductor wiring layer 31, connection section 32, barrier metal 33, and conductive balls 50 are electrically connected in this order.

[0060] The wiring portion (rewiring portion) of the semiconductor device may have multiple conductor wiring layers, and an insulating resin film containing a cured product of the photosensitive resin composition according to the present disclosure may be provided as an interlayer insulating layer provided between adjacent conductor wiring layers. In the semiconductor device, the interlayer insulating layer, the surface protective layer, or both of them may be an insulating resin film containing a cured product of the photosensitive resin composition according to the present disclosure.

[0061] The semiconductor device may be a memory. Examples of electronic devices including the semiconductor device according to the present disclosure include mobile phones, smartphones, tablet terminals, personal computers, and hard disk drives.

[0062] The present invention is not limited to the following examples.

[0063] 1. Raw materials The following raw materials were prepared. (A) Alkali-soluble resins A1: Novolak resin having a phenolic hydroxyl group and an imide group (acid-catalyzed reaction product of bis(o-hydroxy-p-methylphenyl)4,4'-oxyphthalimide and 1,4-bismethoxymethylbenzene, weight-average molecular weight: 270,000) A2: Novolak resin having a phenolic hydroxyl group and an imide group (acid-catalyzed reaction product of bis(o-hydroxy-p-methylphenyl)4,4'-biphthalimide and 1,4-bismethoxymethylbenzene, weight-average molecular weight: 13,000) A3: Novolak resin having a phenolic hydroxyl group and an imide group (acid-catalyzed reaction product of bis(o-hydroxyphenyl)4,4'-oxyphthalimide and 1,4-bismethoxymethylbenzene, weight-average molecular weight: 42,000) A4: Novolak resin having a phenolic hydroxyl group and an imide group (bis(m-hydroxyphenyl)pyrrolimetimide, an acid-catalyzed reaction product of o-cresol and p-cresol with 1,4-bismethoxymethylbenzene and formaldehyde, molar ratio: bis(m-hydroxyphenyl)pyrrolimetimide / o-cresol / p-cresol / 1,4-bismethoxymethylbenzene / formaldehyde = 10 / 60 / 30 / 30 / 70, weight average molecular weight: 150,000) A'1: p-hydroxystyrene-styrene copolymer (molar ratio: p-hydroxystyrene / styrene = 85 / 15, weight average molecular weight: 10,000, manufactured by Maruzen Petrochemical Co., Ltd., trade name "CST85")

[0064] (B) Photoacid generator B1: 1-naphthoquinone-2-diazide-5-sulfonic acid ester of 2,2-bis[4,4-bis(4-hydroxyphenyl)cyclohexyl]propane (a compound represented by formula (10), in which Q is a group represented by formula (3a), esterification rate of approximately 90%, manufactured by Toyo Gosei Co., Ltd., trade name "TEKP-250") B'1: 1-naphthoquinone-2-diazide-5-sulfonic acid ester of 1,1-bis(4-hydroxyphenyl)-1-[4-{1-(4-hydroxyphenyl)-1-methylethyl}phenyl]ethane (a compound represented by formula (11) in which Q is a group represented by formula (3a), esterification rate approximately 63%, manufactured by Daito ChemiX Co., Ltd., trade name "PA28")

[0065] (C) Thermal crosslinking agent C1: 4,4'-[1-[4-[1-[4-hydroxy-3,5-bis(methoxymethyl)phenyl]-1-methylethyl]phenyl]ethylidene]bis[2,6-bis(methoxymethyl)phenol] (represented by formula (42), R ４０ is a methoxymethyl group, manufactured by Honshu Chemical Industry Co., Ltd., trade name "HMOM-TPPA") C2: 2,2-bis(4-hydroxy-3,5-dimethoxymethyl-phenyl)propane (represented by formula (44), R ４０ is a methoxymethyl group, manufactured by Asahi Organic Chemicals Co., Ltd., trade name "TMX-BIP") (D) Silane coupling agent D1: 3-glycidyloxypropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., trade name "KBM403")

[0066] 2. Photosensitive Resin Composition Each component was mixed with a solvent in the blending ratio (parts by mass) shown in Table 1. When the alkali-soluble resin was A1, A2, or A3, the solvent was γ-butyrolactone. When the alkali-soluble resin was A4 or A'1, the solvent was ethyl lactate. The mixture was pressure-filtered through a polytetrafluoroethylene filter with 0.2 μm pores to prepare a photosensitive resin composition.

[0067] 3. Evaluation Via Resolution The photosensitive resin composition was applied to a silicon substrate by spin coating. The coating was heated at 120°C for 3 minutes to remove the solvent, forming a photosensitive layer with a film thickness of 5 to 6 μm. Next, using an i-line stepper (Canon, product name "FPA-3000iW"), the photosensitive layer was subjected to reduced projection exposure with i-line (365 nm) through a mask having a pattern corresponding to through-holes with widths that varied stepwise in the range of 1 μm to 100 μm. The i-line exposure dose was 1000 mJ / cm. ２After exposure, a portion of the photosensitive layer was removed by development using a 2.38% by mass aqueous solution of tetramethylammonium hydroxide (TMAH). The remaining photosensitive layer, which was the insulating resin film, was washed with water. The insulating resin film was observed, and the smallest width of the formed through holes was recorded as the via resolution. A smaller via resolution means better resolution.

[0068] Pattern Angle The photosensitive resin composition was applied to a silicon substrate by spin coating. The coating was heated at 120°C for 3 minutes to remove the solvent, forming a photosensitive layer with a film thickness of 5 to 6 μm. Next, using an i-line stepper (Canon, product name "FPA-3000iW"), the photosensitive layer was subjected to reduced projection exposure with i-line (365 nm) through a mask having a pattern corresponding to the 5 μm-wide through-holes. The i-line exposure dose was 1000 mJ / cm ２ After exposure, a portion of the photosensitive layer was removed by development using a 2.38% by mass aqueous solution of TMAH. The remaining photosensitive layer, which was the insulating resin film, was washed with water. The insulating resin film was observed, and the angle of the wall surface of the through-hole relative to the surface of the silicon substrate was recorded as the pattern angle. A large pattern angle means that a pattern with a good shape was formed.

[0069] Developed Film Remaining Rate The photosensitive resin composition was applied to a silicon substrate by spin coating. The coating was heated at 120°C for 3 minutes to remove the solvent, forming a photosensitive layer with a film thickness of 5 to 6 μm. Next, using an i-line stepper (Canon, product name "FPA-3000iW"), the photosensitive layer was subjected to reduced projection exposure with i-line (365 nm) through a mask having a pattern corresponding to through-holes with a width of 5 μm. The i-line exposure dose was 1000 mJ / cm. ２ After the exposure, a part of the photosensitive layer was removed by development using a TMAH aqueous solution with a concentration of 2.38% by mass. The development time with the TMAH aqueous solution was adjusted to an exposure dose of 1000 mJ / cm. ２ The time was adjusted so that a through hole could be formed when the thickness of the insulating resin film remaining as the photosensitive layer was measured, and the remaining film ratio (%) was calculated as the ratio of the measured thickness to the thickness of the photosensitive layer before exposure.

[0070] Glass transition temperature (Tg) The photosensitive resin composition was applied to a silicon substrate by spin coating. The coating was heated at 120°C for 3 minutes to form a photosensitive layer with a film thickness of 8 to 9 μm. The photosensitive layer was then exposed to light of all wavelengths through a mask using an aligner (manufactured by SUSS MicroTec K.K., product name "MA-8"). The exposure dose was 1500 mJ / cm. ２ After exposure, an insulating resin film having a pattern including 10 mm-wide linear portions was formed by development using a 2.38% TMAH aqueous solution. The formed insulating resin film was heated in an inert gas oven (INH-9CD-S) under a nitrogen atmosphere, with the temperature increased to 230°C over 1 hour and maintained at 230°C for 2 hours, thereby promoting curing of the insulating resin film. The thickness of the cured insulating resin film after heating was approximately 7 μm. The glass transition temperature (Tg) of the formed cured film was measured by thermomechanical analysis using a TMA / 7100 (manufactured by Hitachi High-Tech Corporation). The sample used for the measurement had a width of 4 mm and a film thickness of approximately 7 μm. The measurement conditions were as follows: Chuck distance: 10 mm Load: 10 gf Heating rate: 5°C / min

[0071]

[0072] As shown in Table 1, it was confirmed that the photosensitive resin compositions of the examples, which comprise (A) an alkali-soluble resin having a phenolic hydroxyl group and an imide group, (B) a photoacid generator, and (C) a thermal crosslinker, wherein the photoacid generator comprises a compound represented by formula (I), are capable of forming insulating resin films having well-defined patterns with high resolution. The photosensitive resin compositions of the examples were also excellent in terms of the residual film rate after development and heat resistance.

[0073] 10...semiconductor chip, 11...chip main body portion, 12...pad portion, 13...protective film, 20...wiring portion, 31...conductor wiring layer, 32...connection portion, 33...barrier metal, 41...surface protection layer (insulating layer), 42...cover coat layer (insulating layer), 50...conductive ball, 100...semiconductor device

Claims

1. A photo-acid generating composition comprising: (A) an alkali-soluble resin having a phenolic hydroxyl group and an imide group; (B) a photoacid generator which is a compound that generates an acid by light; and (C) a thermal crosslinking agent which is a compound that crosslinks the alkali-soluble resin by heat, wherein the photoacid generator is represented by the following formula (I): R １ is an alkanediyl group having 1 to 3 carbon atoms; R ２ is an alkyl group having 1 to 3 carbon atoms, p is an integer of 0 to 4, and multiple R ２ may be the same or different, and Q is represented by the following formula (3a), (3b) or (3c): or a hydrogen atom, wherein multiple Q's in one molecule may be the same or different, and at least one of the multiple Q's in one molecule is a group represented by formula (3a), (3b) or (3c).

2. The alkali-soluble resin is represented by the following formula (II): R ３ is a hydrogen atom or an alkyl group having 1 to 3 carbon atoms; Z １ The positive photosensitive resin composition according to claim 1 , wherein is a tetravalent organic group.

3. The positive photosensitive resin composition according to claim 1, wherein the thermal crosslinking agent comprises an alkoxy compound having a plurality of alkoxy groups.

4. A portion of the 5 μm-thick photosensitive layer containing the positive photosensitive resin composition, which corresponds to a through hole having a width of 5 to 20 μm, is exposed to light, and the exposed photosensitive layer is then exposed to light at a dose of 1000 mJ / m ２ 2. The positive photosensitive resin composition according to claim 1, wherein when the composition is developed under conditions in which the through holes are formed with an aqueous tetramethylammonium hydroxide solution having a concentration of 2.38 mass % at an exposure dose of 1000 nm, the thickness of the remaining photosensitive layer is 95% or more of the thickness of the photosensitive layer before exposure.

5. A method for forming an insulating resin film, comprising: exposing a part of a photosensitive layer containing the positive photosensitive resin composition according to any one of claims 1 to 4 to light; forming an insulating resin film having a pattern including openings by developing to remove a part of the photosensitive layer; and heating the insulating resin film.

6. An insulating resin film comprising a cured product of the positive photosensitive resin composition according to any one of claims 1 to 4 and having a pattern including openings.

7. A semiconductor device comprising: a semiconductor chip; and a wiring section including a conductor wiring layer connected to said semiconductor chip and one or more insulating layers, wherein at least a portion of said one or more insulating layers is the insulating resin film according to claim 6.

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