Photosensitive resin composition

Abstract

To provide a photosensitive resin composition which can be developed with an alkaline aqueous solution, does not cause cracks or the like even when cured at 250°C or less, and forms a cured film which has high reliability against mechanical and thermal shock. The resin film of the photosensitive resin composition is formed by irradiating the resin film with 100 to 2000 mJ / cm 2 and heat-treating the cured film at 150 to 250°C for 1 to 3 hours in a nitrogen atmosphere to prepare a strip sample of the cured film having a thickness of 10 μm and a width of 10 mm. When the strip sample is repeatedly pulled under a fatigue test at a set temperature of 25°C, a chuck distance of 20 mm, a test speed of 5 mm / min, and a repeated load stress of 100 MPa, the strip sample is pulled for 100 cycles or more until it breaks.

Description

[Technical Field]

[0001] The present invention relates to a photosensitive resin composition, a method for selecting a photosensitive resin composition, a method for producing a patterned cured film, and a method for producing a semiconductor device. [Background technology]

[0002] To achieve high-speed transmission and miniaturization of semiconductor devices, high-density semiconductor packages have been proposed that combine materials with different physical properties in complex ways. Because such semiconductor packages place large stresses on the semiconductor elements and rewiring layers, materials that can alleviate the stress and have high mechanical reliability are required.

[0003] To reduce the stress on the low-k material formed on semiconductor elements, a surface passivation film capable of relieving stress is required, and fan-out packages require interlayer insulating films that can withstand higher stress than conventional ones. Furthermore, to reduce the low heat resistance of semiconductor elements and the stress on semiconductor packages, materials used for surface passivation films and interlayer insulating films are required to be thermally cured at temperatures below 250°C.

[0004] In response to such demands, it has been proposed to use a patterned cured film formed from a photosensitive resin composition containing a polyimide resin, a polybenzoxazole resin, or a phenolic resin that can be cured at low temperatures as a surface protective film or an interlayer insulating film (see, for example, Patent Documents 1 to 5). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2008-309885 [Patent Document 2] Japanese Patent Application Laid-Open No. 2007-57595 [Patent Document 3] Japanese Patent Application Laid-Open No. 2008-076583 [Patent Document 4] International Publication No. 2010 / 073948 [Patent Document 5] Japanese Patent Application Publication No. 2018-185480 Summary of the Invention [Problem to be solved by the invention]

[0006] Photosensitive resin compositions for forming surface protective films or interlayer insulating films are required to have high reliability even when cured at temperatures of 250°C or less in order to reduce stress, warpage, and damage to semiconductor elements. Furthermore, there is a strong demand for photosensitive materials that can be developed with an alkaline aqueous solution due to environmental load, safety, and equipment constraints. However, these materials are difficult to satisfy with sufficient mechanical reliability in a package configuration that is subject to high stress, and cracks may occur in the protective film or insulating film.

[0007] The present disclosure aims to provide a simple method for selecting a photosensitive resin composition that can be developed with an alkaline aqueous solution, does not generate cracks or the like even when cured at 250°C or less, and forms a cured film that has high reliability against mechanical and thermal shock; a photosensitive resin composition selected by this selection method; a method for producing a patterned cured film using a photosensitive resin composition selected by this selection method; and a method for producing a semiconductor device. [Means for solving the problem]

[0008] One aspect of the present disclosure is to form a resin film of a photosensitive resin composition by applying a radiation of 100 to 2000 mJ / cm 2 and heat-treating the cured film at 150 to 250°C for 1 to 3 hours in a nitrogen atmosphere to prepare a strip sample of the cured film having a thickness of 10 μm and a width of 10 mm. The strip sample is subjected to a fatigue test in which it is repeatedly pulled under the conditions of a set temperature of 25°C, a chuck distance of 20 mm, a test speed of 5 mm / min, and a repeated load stress of 100 MPa, and photosensitive resin compositions are selected that can withstand 100 or more pulling cycles until the strip sample breaks in the fatigue test.

[0009] The fatigue test of the above strip sample may be carried out under the conditions of a set temperature of -55°C, a chuck distance of 20 mm, a test speed of 5 mm / min, and a repeated load stress of 120 MPa.

[0010] Another aspect of the present disclosure is to provide a resin film of a photosensitive resin composition at 100 to 2000 mJ / cm 2 and heat-treating the cured film at 150 to 250°C for 1 to 3 hours in a nitrogen atmosphere to prepare a strip sample of the cured film having a thickness of 10 μm and a width of 10 mm. When the strip sample is repeatedly stretched under a fatigue test at a set temperature of 25°C, a chuck distance of 20 mm, a test speed of 5 mm / min, and a repeated load stress of 100 MPa, or at a set temperature of -55°C, a chuck distance of 20 mm, a test speed of 5 mm / min, and a repeated load stress of 120 MPa, the strip sample is stretched 100 cycles or more until it breaks.

[0011] Another aspect of the present disclosure relates to a method for producing a patterned cured film, including the steps of applying a photosensitive resin composition selected by the above-described method for selecting a photosensitive resin composition to a part or the entire surface of a substrate and drying the composition to form a resin film, exposing at least a part of the resin film to light, developing the exposed resin film to form a patterned resin film, and heating the patterned resin film.

[0012] Another aspect of the present disclosure relates to a method for manufacturing a semiconductor device, including a patterned cured film formed by the above-described method for manufacturing a patterned cured film, as an interlayer insulating layer or a surface protective layer. [Effects of the Invention]

[0013] According to the present disclosure, it is possible to provide a simple method for selecting a photosensitive resin composition that can be developed with an alkaline aqueous solution, does not generate cracks or the like even when cured at 250°C or less, and forms a cured film that has high reliability against mechanical and thermal shock.

[0014] The present disclosure provides a method for selecting a photosensitive resin composition that does not crack due to thermal shock such as a temperature cycle test when used in a surface protective film or an interlayer insulating film. Materials are selected through fatigue tests at 25°C or at an unprecedentedly low temperature of -55°C. Fatigue fracture resistance at 25°C and -55°C correlates with thermal shock reliability (packaging reliability). This simple and quick fatigue test allows for quick and easy evaluation of thermal shock reliability (packaging reliability), which typically requires time for sample preparation and evaluation. When a patterned cured film is produced using the selected photosensitive resin composition, a semiconductor device with excellent thermal shock reliability can be manufactured that does not develop cracks or the like during a temperature cycle test. [Brief explanation of the drawings]

[0015] [Figure 1] 1A to 1C are schematic cross-sectional views illustrating an embodiment of a manufacturing process for a semiconductor device. [Figure 2] 1A to 1C are schematic cross-sectional views illustrating an embodiment of a manufacturing process for a semiconductor device. [Figure 3] 1A to 1C are schematic cross-sectional views illustrating an embodiment of a manufacturing process for a semiconductor device. [Figure 4] 1A to 1C are schematic cross-sectional views illustrating an embodiment of a manufacturing process for a semiconductor device. [Figure 5] 1A to 1C are schematic cross-sectional views illustrating an embodiment of a manufacturing process for a semiconductor device. [Figure 6] 1 is a schematic cross-sectional view showing an embodiment of an electronic component (semiconductor device). [Figure 7] 1 is a schematic cross-sectional view showing an embodiment of an electronic component (semiconductor device). DETAILED DESCRIPTION OF THE INVENTION

[0016] Hereinafter, embodiments for carrying out the present disclosure will be described in detail. However, the present invention is not limited to the following embodiments. In this specification, 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 effect of the process is achieved. In this specification, the term "layer" includes a structure with a shape formed on the entire surface as well as a structure with a shape formed on a part of the surface when observed in a plan view.

[0017] In this specification, a numerical range indicated using "to" indicates a range that includes 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 in one stage may be replaced with the upper or lower limit of a numerical range in another stage. Furthermore, in numerical ranges described in this specification, the upper or lower limit of that numerical range may be replaced with a value shown in an example.

[0018] When referring to the amount of each component in a composition herein, if the composition contains multiple substances corresponding to each component, the total amount of the multiple substances present in the composition is used unless otherwise specified. In this specification, "(meth)acrylic acid" refers to at least one of "acrylic acid" and its corresponding "methacrylic acid." The same applies to other similar expressions such as (meth)acrylate.

[0019] [Method for selecting photosensitive resin composition] In one aspect of the method for selecting a photosensitive resin composition according to the present embodiment, a resin film of the photosensitive resin composition is subjected to irradiation with 100 to 2000 mJ / cm 2 2 The cured film is exposed to light at 1000 Hz, and then heat-treated in nitrogen at 150 to 250°C for 1 to 3 hours to prepare a strip sample of the cured film having a thickness of 10 μm and a width of 10 mm. A fatigue test is then conducted in which the strip sample is repeatedly pulled under the conditions of a set temperature of 25°C, a chuck distance of 20 mm, a test speed of 5 mm / min, and a repeated load stress of 100 MPa, and photosensitive resin compositions are selected that can withstand 100 or more pulling cycles until the strip sample breaks in the fatigue test.

[0020] In another aspect of the method for selecting a photosensitive resin composition according to the present embodiment, a resin film of the photosensitive resin composition is subjected to irradiation with 100 to 2000 mJ / cm 2 2 The cured film is exposed to light at 100°C and then heat-treated in a nitrogen atmosphere at 150 to 250°C for 1 to 3 hours to prepare a strip sample of the cured film having a thickness of 10 μm and a width of 10 mm. A fatigue test is then carried out in which the strip sample is repeatedly pulled under the conditions of a set temperature of -55°C, a chuck distance of 20 mm, a test speed of 5 mm / min, and a repeated load stress of 120 MPa, and photosensitive resin compositions are selected that can withstand 100 or more pulling cycles until the strip sample breaks in the fatigue test.

[0021] The procedure for the method for selecting a photosensitive resin composition according to this embodiment will be described in detail below. First, the photosensitive resin composition is applied to a substrate and dried to form a resin film. The type of substrate is not particularly limited, and for example, a silicon wafer with copper formed on its surface can be used. The photosensitive resin composition may be applied to the copper surface of the silicon wafer using a spin coater. The resin film is exposed and developed to form a resin pattern on the copper. The exposure conditions for the resin film are 500 to 1500 mJ / cm. 2 , or 800 to 1200 mJ / cm 2 The exposed resin film can be developed using a developer such as an alkaline aqueous solution to obtain a resin pattern. The resin pattern can be heated under nitrogen to form a cured film of the resin pattern. The heating temperature of the resin pattern can be 160 to 230°C or 180 to 220°C, and the heating time can be 1.5 to 2.5 hours or 1.8 to 2.2 hours. The substrate on which the cured film of the resin pattern has been formed can be immersed in a copper etching solution to obtain a strip sample (a strip-shaped cured film) for fatigue testing.

[0022] In the method for selecting a photosensitive resin composition according to the present embodiment, a fatigue test is performed on a strip sample, and photosensitive resin compositions that can withstand 100 or more cycles of tension before the strip sample breaks are selected. The fatigue test can be performed under either the following conditions (1) or (2). Condition (1): The strip sample is repeatedly pulled (0 to 100 MPa) under the conditions of a set temperature of 25°C, a chuck distance of 20 mm, a test speed of 5 mm / min, and a repeated load stress of 100 MPa. Condition (2): The strip sample is repeatedly pulled (0 to 120 MPa) under the conditions of a set temperature of -55°C, a chuck distance of 20 mm, a test speed of 5 mm / min, and a repeated load stress of 120 MPa.

[0023] By selecting a photosensitive resin composition that can withstand 100 or more tensile cycles until a strip sample breaks in a fatigue test, a cured film with excellent thermal shock reliability can be obtained, and the occurrence of cracks and the like can be reduced in temperature cycle tests for semiconductor packages. The number of tensile cycles at which the strip sample breaks in a fatigue test is defined as "fatigue fracture resistance." The number of tensile cycles at which the strip sample breaks is preferably 250 or more, more preferably 500 or more, even more preferably 800 or more, and particularly preferably 1000 or more.

[0024] The photosensitive resin composition selected by the method for selecting a photosensitive resin composition according to this embodiment can suppress cracks in the resin layer even in a package that is significantly warped and that is subject to stresses caused by the difference in linear expansion coefficients between copper and resin, and organic materials such as encapsulants, and can manufacture a semiconductor device that is highly reliable against thermal shock due to temperature cycles, even in a package configuration that is subject to high stress.

[0025] After 100 cycles of fatigue testing, the strip sample is subjected to a tensile test in which the strip sample is pulled at a set temperature of 25°C, a chuck distance of 20 mm, and a test speed of 5 mm / min. The elongation at break of the strip sample is preferably 10 to 60%. When the elongation of the cured film is 10% or more, stress is easily relieved, and stress tends to be concentrated on the semiconductor element or other organic components, improving the reliability of the semiconductor package. When the elongation of the cured film is 60% or less, the cured film tends to be less likely to become brittle during temperature cycling. The elongation of the cured film is more preferably 15% or more in terms of better stress relief, and even more preferably 20% or more in terms of improved crack resistance.

[0026] The elongation percentage is obtained by measuring the elongation percentage at the time of fracture of a sample after 100 cycles of fatigue testing under condition (1) or condition (2) using a special autograph with a constant temperature bath (AG-1kNXplus) manufactured by Shimadzu Corporation, at a set temperature of -55°C, a chuck distance of 20 mm, and a test speed of 5 mm / min.

[0027] The yield stress of the strip sample (cured film of the photosensitive resin composition) measured in the tensile test is preferably 120 to 200 MPa. When the yield stress is 120 MPa or more, the cured film is less likely to undergo plastic deformation in a package with high stress, making it less likely to develop defects due to repeated stress. When the yield stress of the cured film is 200 MPa or less, impact resistance tends to be improved. The yield stress of the cured film is more preferably 125 MPa or more, and even more preferably 140 MPa or more, in terms of maintaining crack resistance after thermal history.

[0028] The yield stress can be obtained by plotting a curve in the above tensile test with elongation on the horizontal axis and stress on the vertical axis, and taking the stress value at the intersection of the tangent to the plot showing 5% elongation and the tangent to the plot showing 15% elongation as the yield stress.

[0029] In the tensile test, measurements are made under three different stress conditions resulting in a number of repeated pulls ranging from 2 to 1000. The horizontal axis represents the number of repeated pulls at which the sample breaks, and the vertical axis represents the stress conditions under which the sample breaks. The stress value at 1000 cycles on the approximate straight line obtained from the three points can be determined as the critical stress of the cured film of the photosensitive resin composition. The critical stress of the cured film is preferably 120 MPa or more, and more preferably 125 MPa or more in terms of maintaining crack resistance after thermal history.

[0030] The Young's modulus of the strip sample measured in the tensile test is preferably 0.5 to 2.8 GPa. When the Young's modulus of the cured film is 0.5 GPa or more, the cured film is less likely to deform when stress is applied, making it easier to prevent stress from concentrating on materials with a high Young's modulus that are mounted on semiconductor packages. When the Young's modulus of the cured film is 2.8 GPa or less, the cured film relieves stress and is less likely to damage semiconductor elements. The Young's modulus of the cured film is more preferably 1.0 to 2.7 GPa, and even more preferably 1.4 to 2.6 GPa.

[0031] In the above tensile test, Young's modulus can be calculated from the slope of a curve obtained by plotting elongation on the horizontal axis and stress on the vertical axis in an elongation range of 0 to 5%.

[0032] The glass transition temperature (Tg) of the cured film of the photosensitive resin composition according to this embodiment is preferably 150° C. or higher, more preferably 170° C. or higher, and even more preferably 180° C. or higher. When the Tg of the cured film is 150° C. or higher, stress during temperature changes such as in a temperature cycle test can be reduced. The upper limit of the Tg of the cured film may be 300° C. or lower.

[0033] Tg can be determined by measuring the viscoelasticity of the above-mentioned strip sample using a dynamic viscoelasticity measuring device manufactured by UBM Corporation at a chuck distance of 20 mm, a frequency of 10 Hz, and a temperature rise rate of 5°C / min in the temperature range of 40 to 260°C, and the temperature at which tan δ reaches its maximum value can be taken as the glass transition temperature.

[0034] The linear expansion coefficient of the cured film of the photosensitive resin composition according to this embodiment is 20 to 100 ppm / °C (20 × 10 -6 ~100×10 -6 When the linear expansion coefficient of the cured film is 100 ppm / °C or less, stress caused by temperature changes can be suppressed. When the linear expansion coefficient of the cured film is 20 ppm / °C or more, the occurrence of cracks can be easily suppressed.

[0035] The adhesion rate of the cured film of the photosensitive resin composition according to this embodiment to the electroplated copper substrate is preferably 75% or more. If the adhesion rate is 75% or more, the cured film will peel off from the underlying electroplated copper pattern when stress is applied, and stress will tend to concentrate on the material with a high adhesion rate to the electroplated copper mounted on the semiconductor package. The higher the adhesion rate, the better, with 90% or more being more preferable, 95% or more being even more preferable, and 100% being particularly preferable.

[0036] The adhesion rate can be measured by the following procedure. First, a photosensitive resin composition is applied to an electrolytically plated copper substrate using a spin coater so that the cured film thickness is 10 μm. The photosensitive resin composition is then heated under nitrogen at 200°C for 2 hours to form a cured film. Next, the cured film is subjected to a temperature cycle test 200 times under atmospheric pressure air atmosphere, at temperatures from -65 to 150°C, with a 15-minute pause, starting and ending at -65°C. After this, the cured film is cut into a grid pattern using the cross-cut method specified in JIS K 5600-5-6. A tape peel test is performed on the cured film cut into a grid pattern, and the proportion of the grid (cured film) adhering to the electrolytically plated copper substrate (adhesion rate) is calculated.

[0037] When the photosensitive resin composition according to the embodiment is subjected to the fatigue test described above, the number of pulling cycles until a strip sample breaks is 100 or more. The photosensitive resin composition may be a positive-type photosensitive resin composition or a negative-type photosensitive resin composition. The photosensitive resin composition may contain, for example, (A) an alkali-soluble resin, (B) a thermosetting resin, and (C) a photosensitizer. Each component that may be contained in the photosensitive resin composition will be described in detail below.

[0038] (Component (A): alkali-soluble resin) The photosensitive resin composition according to this embodiment may contain an alkali-soluble resin as component (A) in order to improve alkaline developability. In this specification, the alkali-soluble resin refers to a resin that is soluble in an alkaline aqueous solution (developer). The alkaline aqueous solution is an alkaline solution such as a tetramethylammonium hydroxide (TMAH) aqueous solution, a metal hydroxide aqueous solution, or an organic amine aqueous solution. Generally, a TMAH aqueous solution with a concentration of 2.38% by mass is used for development. The solubility of component (A) in an alkaline developer can be confirmed, for example, as follows.

[0039] A varnish obtained by dissolving a resin in a solvent is spin-coated onto a substrate such as a silicon wafer to form a coating film with a thickness of approximately 5 μm. This is then immersed in either an aqueous TMAH solution, an aqueous metal hydroxide solution, or an aqueous organic amine solution at 20 to 25°C. If the resulting coating film is uniformly soluble, the resin can be considered soluble in an alkaline developer.

[0040] There are no particular limitations on the component (A) as long as it dissolves in a 2.38% by mass aqueous solution of TMAH, but it is preferably a compound having a phenolic hydroxyl group or a carboxyl group.

[0041] Examples of the compound having a phenolic hydroxyl group include polyimide resins, polybenzoxazole resins, polyamide resins, novolak resins which are condensates of phenol and formaldehyde, cresol and formaldehyde condensed novolak resins, phenol-naphthol / formaldehyde condensed novolak resins, polyhydroxystyrene or copolymers thereof, phenol-xylylene glycol condensed resins, cresol-xylylene glycol condensed resins, phenol-dicyclopentadiene condensed resins, and acrylic polymers having a phenolic hydroxyl group.

[0042] The acrylic polymer having a phenolic hydroxyl group is not particularly limited, but an acrylic polymer represented by the following general formula (1) can be used: In formula (1), R1 represents a hydrogen atom or a methyl group.

[0043] [ka]

[0044] The phenolic hydroxyl group equivalent of the acrylic polymer having a phenolic hydroxyl group is preferably 200 to 700 g / eq from the viewpoint of pattern formability and reducing voids during thermocompression bonding.

[0045] The acrylic polymer having a phenolic hydroxyl group may be a copolymer having a structural unit represented by formula (1) as well as a structural unit other than the structural unit represented by formula (1) (hereinafter simply referred to as "other structural units"). The other structural units are structural units derived from monomers copolymerizable with the monomer having the structural unit represented by formula (1). The monomer having the other structural unit is not particularly limited, but a (meth)acrylate compound or a vinyl compound can be used.

[0046] Examples of monomers having other structural units include methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, octyl acrylate, methoxymethyl acrylate, methoxyethyl acrylate, ethoxyethyl acrylate, butoxyethyl acrylate, methoxyethoxyethyl acrylate, acrylic acid, methacrylic acid, hydroxyethyl acrylate, hydroxyethyl methacrylate, acrylonitrile, methacrylonitrile, ethacrylonitrile, dihydrodicyclopentenyl acrylate, dihydrodicyclopentenyl methacrylate, dihydrodicyclopentenyl itaconate, dihydrodicyclopentenyl maleate, dihydrodicyclopentenyl fumarate, dihydrodicyclopentenyloxyethyl acrylate, dihydrodicyclopentenyloxyethyl methacrylate, dihydrodicyclopentenyloxyethyl itaconate, and dihydrodicyclopentenyl maleate. Oxyethyl, dihydrodicyclopentenyloxyethyl fumarate, vinyl methacrylate, vinyl acrylate, 1,1-dimethylpropenyl methacrylate, 1,1-dimethylpropenyl acrylate, 3,3-dimethylbutenyl methacrylate, 3,3-dimethylbutenyl acrylate, divinyl itaconate, divinyl maleate, divinyl fumarate, dicyclopentadiene, methyldicyclopentadiene, ethylidenenorbornene, 1,1-dimethylpropenyl methacrylate, 1,1-dimethylpropenyl acrylate, 3,3-dimethylbutenyl methacrylate, 3,3-dimethylbutenyl acrylate, vinyl 1,1-dimethylpropenyl ether, vinyl 3,3-dimethylbutenyl ether, 1-acryloyloxy-1-phenylethene, 1-acryloyloxy-2-phenylethene, 1-methacryloyloxy-1-phenylethene, and 1-methacryloyloxy-2-phenylethene.

[0047] Component (A) may contain a compound having a carboxyl group. The compound having a carboxyl group is not particularly limited, but an acrylic polymer having a carboxyl group in the side chain is preferably used.

[0048] The component (A) may be a mixture of (A1) an alkali-soluble resin having a Tg of 150° C. or higher and (A2) an alkali-soluble resin having a Tg of 120° C. or lower. This configuration allows for the production of a cured film with even greater reliability.

[0049] When mixing (A1) an alkali-soluble resin with a Tg of 150°C or higher and (A2) an alkali-soluble resin with a Tg of 120°C or lower, it is preferable to mix 5 to 30 parts by mass of (A2) per 100 parts by mass of (A1). If the amount of (A2) is 5 parts by mass or more, the elongation of the cured film tends to be impaired and the fatigue fracture resistance tends to decrease, while if it is 30 parts by mass or less, the strength of the cured film tends to be impaired and the fatigue fracture resistance tends to decrease.

[0050] The Tg of component (A) is the peak temperature of tan δ when a film of component (A) is measured using a viscoelasticity analyzer (product name "RSA-2", manufactured by Rheometrics) at a heating rate of 5°C / min, a frequency of 1 Hz, and a measurement temperature of -150 to 300°C.

[0051] The weight-average molecular weight (Mw) of component (A) is preferably controlled within the range of 2,000 to 200,000, more preferably 3,000 to 100,000, and even more preferably 5,000 to 80,000. In particular, the Mw of the alkali-soluble resin (A1) is preferably 2,000 to 50,000, more preferably 4,000 to 30,000 from the viewpoint of reliability, and even more preferably 2,000 to 30,000 from the viewpoint of resolution during pattern formation. Furthermore, the Mw of the alkali-soluble resin (A2) is preferably 10,000 to 100,000, more preferably 15,000 to 100,000 from the viewpoint of reliability, and even more preferably 15,000 to 70,000 from the viewpoint of resolution during pattern formation.

[0052] In this specification, Mw is a value obtained by measuring by gel permeation chromatography (GPC) and converting it using a standard polystyrene calibration curve. As a measuring device, for example, a high performance liquid chromatograph (trade name "C-R4A", manufactured by Shimadzu Corporation) can be used.

[0053] From the viewpoint of further improving fatigue fracture resistance, component (A) may contain an alkali-soluble resin having an imide group. As the alkali-soluble resin having an imide group, an acrylic polymer obtained by polymerizing a (meth)acrylate compound having an imide group is preferably used, since the concentration of the imide group can be adjusted as desired. As the alkali-soluble resin having an imide group, an alkali-soluble polyimide can also be used. From the viewpoint of resolution, the alkali-soluble resin having an imide group is preferably used in combination with a novolac resin or a phenolic resin.

[0054] The alkali-soluble resin having an imide group may be a copolymer of a (meth)acrylate compound having an imide group and a (meth)acrylate compound having a phenolic hydroxyl group or a carboxyl group. Examples of the (meth)acrylate compound having an imide group include N-acryloyloxyethylhexahydrophthalimide and N-methacryloyloxyethylhexahydrophthalimide. The proportion of structural units based on the (meth)acrylate compound having an imide group, based on all monomer units constituting the alkali-soluble resin having an imide group, is preferably 10% by mass or more in order to improve the toughness of the cured film, more preferably 20% by mass or more in order to impart sufficient fatigue fracture resistance, and preferably 60% by mass or less in order to maintain alkali solubility.

[0055] The content of the alkali-soluble resin having an imide group, based on the total amount of component (A), is preferably 10% by mass or more in terms of improving the toughness of the cured film, more preferably 20% by mass or more in terms of suppressing deterioration during thermal history, and even more preferably 30% by mass or more in terms of imparting sufficient fatigue fracture resistance.

[0056] Component (A) may contain an alkali-soluble resin having an imide group and an alkali-soluble resin not having an imide group, which allows for a high degree of compatibility between fine processability during development of the photosensitive resin composition and fatigue fracture resistance of the cured film.

[0057] The content of the alkali-soluble resin having an imide group, based on the total amount of solids contained in the photosensitive resin composition, is preferably 5% by mass or more in terms of improving the strength of the cured film, more preferably 10% by mass or more in terms of improving the fatigue fracture strength, even more preferably 20% by mass or more in terms of maintaining sufficient fatigue fracture strength even after thermal degradation of the cured film, even more preferably 30% by mass or more in terms of improving the toughness of the cured film, and preferably 80% by mass or less in terms of maintaining the micro-processability of the photosensitive resin composition during development. The content of the alkali-soluble resin having an imide group contained in the photosensitive resin composition is particularly preferably 30 to 80% by mass.

[0058] ((B) component: thermosetting resin) The photosensitive resin composition according to this embodiment preferably contains a thermosetting resin (B). Examples of the thermosetting resin (B) include acrylate resins, epoxy resins, cyanate ester resins, maleimide resins, allylnadimide resins, phenolic resins, urea resins, melamine resins, alkyd resins, unsaturated polyester resins, diallyl phthalate resins, silicone resins, resorcinol formaldehyde resins, triallyl cyanurate resins, polyisocyanate resins, resins containing tris(2-hydroxyethyl)isocyanurate, resins containing triallyl trimellitate, and thermosetting resins synthesized from cyclopentadiene. From the viewpoints of the resolution, insulation reliability, and adhesion to metals of the photosensitive resin composition, the thermosetting resin is preferably a compound having a methylol group, an alkoxyalkyl group, or a glycidyl group.

[0059] By incorporating a compound having a glycidyl group as component (B) into a photosensitive resin composition, when the resin film after pattern formation is heated and cured, it reacts with component (A) to form a crosslinked structure. This prevents the cured film from becoming brittle and melting. Conventional known compounds having a glycidyl group can be used. Examples of compounds having a glycidyl group include bisphenol A epoxy resin, bisphenol F epoxy resin, phenol novolac epoxy resin, cresol novolac epoxy resin, alicyclic epoxy resin, glycidyl amine, heterocyclic epoxy resin, and polyalkylene glycol diglycidyl ether.

[0060] When a compound having a glycidyl group is blended into the photosensitive resin composition, the amount is preferably 1 to 30 parts by mass, and more preferably 3 to 25 parts by mass, per 100 parts by mass of component (A), from the viewpoints of solubility in an alkaline aqueous solution and the physical properties of the cured film.

[0061] (Component (C): Photosensitizer) The photosensitive resin composition according to this embodiment preferably contains a photosensitizer (C). As the photosensitizer (C), a photoradical polymerization initiator that generates radicals upon light irradiation or a photoacid generator that generates an acid upon light irradiation can be used.

[0062] Examples of the photo-radical polymerization initiator include alkylphenone-based photo-polymerization initiators, acylphosphine-based photo-polymerization initiators, intramolecular hydrogen abstraction photo-polymerization initiators, and cationic photo-polymerization initiators. These photo-polymerization initiators are commercially available from IGM Resins as Omnirad 651, Omnirad 184, Omnirad 1173, Omnirad 2959, Omnirad 127, Omnirad 907, Omnirad 369, Omnirad 379EG, Omnirad 819, Omnirad MBF, Omnirad TPO, and Omnirad 784; and from BASF as Irgacure OXE01, Irgacure OXE02, Irgacure OXE03, and Irgacure OXE04. These photoradical polymerization initiators may be used alone or in combination of two or more depending on the purpose, application, etc.

[0063] Photoacid generators generate acid upon irradiation with light, and have the function of increasing the solubility of the irradiated portion in an alkaline aqueous solution. Examples of photoacid generators include o-quinonediazide compounds, aryldiazonium salts, diaryliodonium salts, and triarylsulfonium salts. Among these, o-quinonediazide compounds are preferred due to their high sensitivity. Examples of o-quinonediazide compounds that can be used include compounds obtained by condensing o-quinonediazide sulfonyl chloride with a hydroxy compound, an amino compound, or the like in the presence of a dehydrochlorinating agent. The reaction temperature may be 0 to 40°C, and the reaction time may be 1 to 10 hours.

[0064] Examples of o-quinone diazide sulfonyl chlorides include benzoquinone-1,2-diazide-4-sulfonyl chloride, naphthoquinone-1,2-diazide-5-sulfonyl chloride, and naphthoquinone-1,2-diazide-4-sulfonyl chloride.

[0065] Examples of hydroxy compounds include hydroquinone, resorcinol, pyrogallol, bisphenol A, bis(4-hydroxyphenyl)methane, 1,1-bis(4-hydroxyphenyl)-1-[4-{1-(4-hydroxyphenyl)-1-methylethyl}phenyl]ethane, 2,2-bis(4-hydroxyphenyl)hexafluoropropane, 2,3,4-trihydroxybenzophenone, 2,3,4,4'-tetrahydroxybenzophenone, and 2,2',4,4'-tetrahydroxybenzophenone. benzophenone, 2,3,4,2',3'-pentahydroxybenzophenone, 2,3,4,3',4',5'-hexahydroxybenzophenone, bis(2,3,4-trihydroxyphenyl)methane, bis(2,3,4-trihydroxyphenyl)propane, 4b,5,9b,10-tetrahydro-1,3,6,8-tetrahydroxy-5,10-dimethylindeno[2,1-a]indene, tris(4-hydroxyphenyl)methane, and tris(4-hydroxyphenyl)ethane.

[0066] Examples of the amino compound include p-phenylenediamine, m-phenylenediamine, 4,4'-diaminodiphenyl ether, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenyl sulfone, 4,4'-diaminodiphenyl sulfide, o-aminophenol, m-aminophenol, p-aminophenol, 3,3'-diamino-4,4'-dihydroxybiphenyl, 4,4'-diamino-3,3'-dihydroxybiphenyl, bis(3-amino-4-hydroxyphenyl)propane, bis(4-amino-3-hydroxyphenyl)propane, bis(3-amino-4-hydroxyphenyl)sulfone, bis(4-amino-3-hydroxyphenyl)sulfone, bis(3-amino-4-hydroxyphenyl)hexafluoropropane, and bis(4-amino-3-hydroxyphenyl)hexafluoropropane.

[0067] From the viewpoint of reactivity during synthesis of the o-quinone diazide compound and an appropriate absorption wavelength range during exposure of a resin film, it is preferable to use a compound obtained by a condensation reaction between 1,1-bis(4-hydroxyphenyl)-1-[4-{1-(4-hydroxyphenyl)-1-methylethyl}phenyl]ethane and 1-naphthoquinone-2-diazide-5-sulfonyl chloride, or a compound obtained by a condensation reaction between tris(4-hydroxyphenyl)methane or tris(4-hydroxyphenyl)ethane and 1-naphthoquinone-2-diazide-5-sulfonyl chloride.

[0068] Examples of the dehydrochlorinating agent include sodium carbonate, sodium hydroxide, sodium bicarbonate, potassium carbonate, potassium hydroxide, trimethylamine, triethylamine, and pyridine. Examples of the reaction solvent include dioxane, acetone, methyl ethyl ketone, tetrahydrofuran, diethyl ether, and N-methylpyrrolidone.

[0069] The o-quinone diazide sulfonyl chloride and the hydroxy compound and / or amino compound are preferably blended so that the total moles of the hydroxy group and the amino group per mole of o-quinone diazide sulfonyl chloride is 0.5 to 1. The preferred blending ratio of the dehydrochlorinating agent to o-quinone diazide sulfonyl chloride is in the range of 0.95 / 1 to 1 / 0.95 molar equivalents.

[0070] The content of component (C) is preferably 3 to 100 parts by mass, more preferably 5 to 50 parts by mass, and even more preferably 5 to 30 parts by mass per 100 parts by mass of component (A), in terms of the difference in dissolution rate between exposed and unexposed areas and the tolerance range of sensitivity.

[0071] (Component (D): a low molecular weight compound having a phenolic hydroxyl group) The photosensitive resin composition according to the embodiment may contain a low molecular weight compound having a phenolic hydroxyl group. The low molecular weight compound having a phenolic hydroxyl group is used to increase the dissolution rate of the exposed area during development with an alkaline aqueous solution and improve sensitivity. By including component (D), when the resin film after pattern formation is heated and cured, component (D) reacts with component (A) to form a crosslinked structure. This prevents the cured film from becoming brittle and melting.

[0072] The molecular weight of component (D) is preferably 2000 or less, and in consideration of solubility in an alkaline aqueous solution and the balance between photosensitive characteristics and cured film properties, the number average molecular weight (Mn) is preferably 94 to 2000, more preferably 108 to 2000, and even more preferably 108 to 1500.

[0073] As the low molecular weight compound having a phenolic hydroxyl group, conventionally known compounds can be used, but the compound represented by the following general formula (2) is particularly preferred because it has an excellent balance between the effect of promoting dissolution of the exposed area and the effect of preventing melting during curing of the resin film.

[0074] [ka]

[0075] In formula (2), X represents a single bond or a divalent organic group, and R 1 , R 2 , R 3 and R 4 each independently represents a hydrogen atom or a monovalent organic group; s and t each independently represent an integer of 1 to 3; u and v each independently represent an integer of 0 to 4.

[0076] In formula (2), a compound in which X is a single bond is a biphenol (dihydroxybiphenyl) derivative. Examples of the divalent organic group represented by X include alkylene groups having 1 to 10 carbon atoms, such as methylene, ethylene, and propylene; alkylidene groups having 2 to 10 carbon atoms, such as ethylidene; arylene groups having 6 to 30 carbon atoms, such as phenylene; groups in which some or all of the hydrogen atoms of these hydrocarbon groups have been substituted with halogen atoms, such as fluorine atoms; sulfone groups; carbonyl groups; ether bonds; thioether bonds; and amide bonds. Among these, divalent organic groups represented by the following general formula (3) are preferred:

[0077] [ka]

[0078] In formula (3), X' represents a single bond, an alkylene group (for example, an alkylene group having 1 to 10 carbon atoms), an alkylidene group (for example, an alkylidene group having 2 to 10 carbon atoms), a group in which some or all of the hydrogen atoms of these groups have been substituted with halogen atoms, a sulfone group, a carbonyl group, an oxy group, a thio group, or an amido group; R" represents a hydrogen atom, a hydroxy group, an alkyl group, or a haloalkyl group; g represents an integer of 1 to 10; and multiple R"s may be the same or different.

[0079] The amount of the low molecular weight compound having a phenolic hydroxyl group added is preferably 1 to 50 parts by mass, more preferably 2 to 30 parts by mass, and even more preferably 3 to 25 parts by mass, per 100 parts by mass of component (A), from the standpoints of the development time, the tolerance for the residual film rate in unexposed areas, and the properties of the cured film.

[0080] (Other ingredients) In addition to the above, the photosensitive resin composition according to the embodiment may further contain components such as a compound that generates an acid upon heating, an elastomer, a dissolution promoter, a dissolution inhibitor, a coupling agent, a solvent, a surfactant, and a leveling agent.

[0081] (Compounds that produce acids when heated) The photosensitive resin composition according to the embodiment may contain a compound that generates an acid upon heating. By using a compound that generates an acid upon heating, it becomes possible to generate an acid when the patterned resin film is heated, which promotes the reaction between the (A), (B), and (D) components, i.e., the thermal crosslinking reaction, and improves the heat resistance of the patterned cured film. Furthermore, since the compound that generates an acid upon heating also generates an acid upon light irradiation, the solubility of the exposed portion in an alkaline aqueous solution increases. This further increases the difference in solubility in an alkaline aqueous solution between the unexposed and exposed portions, further improving the resolution.

[0082] The compound that generates an acid upon heating is preferably one that generates an acid upon heating to, for example, 50 to 250° C. 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 imidosulfonates.

[0083] Examples of onium salts include diaryliodonium salts such as aryldiazonium salts and diphenyliodonium salts; di(alkylaryl)iodonium salts such as diaryliodonium salts and di(t-butylphenyl)iodonium salts; trialkylsulfonium salts such as trimethylsulfonium salts; dialkylmonoarylsulfonium salts such as dimethylphenylsulfonium salts; diarylmonoalkyliodonium salts such as diphenylmethylsulfonium salts; and triarylsulfonium salts. Among these, di(t-butylphenyl)iodonium salt of paratoluenesulfonic acid, di(t-butylphenyl)iodonium salt of trifluoromethanesulfonic acid, trimethylsulfonium salt of trifluoromethanesulfonic acid, dimethylphenylsulfonium salt of trifluoromethanesulfonic acid, diphenylmethylsulfonium salt of trifluoromethanesulfonic acid, di(t-butylphenyl)iodonium salt of nonafluorobutanesulfonic acid, diphenyliodonium salt of camphorsulfonic acid, diphenyliodonium salt of ethanesulfonic acid, dimethylphenylsulfonium salt of benzenesulfonic acid, and diphenylmethylsulfonium salt of toluenesulfonic acid are preferred.

[0084] In addition to the onium salts described above, salts formed from strong acids and bases such as pyridinium salts can also be used as salts formed from the following strong acids and bases. Examples of strong acids include arylsulfonic acids such as p-toluenesulfonic acid and benzenesulfonic acid; perfluoroalkylsulfonic acids such as camphorsulfonic acid, trifluoromethanesulfonic acid, and nonafluorobutanesulfonic acid; and alkylsulfonic acids such as methanesulfonic acid, ethanesulfonic acid, and butanesulfonic acid. Examples of bases include alkylpyridines such as pyridine and 2,4,6-trimethylpyridine, N-alkylpyridines such as 2-chloro-N-methylpyridine, and halogenated N-alkylpyridines.

[0085] Imidosulfonates include, for example, naphthoylimidosulfonates and phthalimidosulfonates.

[0086] In addition to the compounds described above, compounds having a structure represented by the following general formula (4) or compounds having a sulfonamide structure represented by the following general formula (5) can also be used as compounds that generate an acid upon heating. R 5 R 6 C=NO-SO2-R 7 (4) -NH-SO2-R 8 (5)

[0087] In formula (4), R 5 is, for example, a cyano group, and R 6 is, for example, a methoxyphenyl group, a phenyl group, etc., and R 7 is, for example, an aryl group such as a p-methylphenyl group or a phenyl group; an alkyl group such as a methyl group, an ethyl group or an isopropyl group; or a perfluoroalkyl group such as a trifluoromethyl group or a nonafluorobutyl group.

[0088] In formula (5), R 8is, for example, an alkyl group such as a methyl group, an ethyl group, or a propyl group, an aryl group such as a methylphenyl group or a phenyl group, or a perfluoroalkyl group such as a trifluoromethyl group or a nonafluorobutyl group. Examples of the group bonded to the N atom of the sulfonamide structure represented by general formula (5) include 2,2'-bis(4-hydroxyphenyl)hexafluoropropane, 2,2'-bis(4-hydroxyphenyl)propane, and di(4-hydroxyphenyl)ether.

[0089] When a compound that generates an acid upon heating is used, the amount added may be 0.1 to 30 parts by mass, 0.2 to 20 parts by mass, or 0.5 to 10 parts by mass per 100 parts by mass of the component (A).

[0090] (Elastomer) The photosensitive resin composition according to the embodiment may contain an elastomer component in addition to the above. The elastomer is used to impart flexibility to the cured product of the photosensitive resin composition. As the elastomer, a conventionally known elastomer can be used, but it is preferable that the Tg of the polymer constituting the elastomer is 20°C or less.

[0091] Examples of the elastomer include styrene-based elastomers, olefin-based elastomers, urethane-based elastomers, polyester-based elastomers, polyamide-based elastomers, acrylic-based elastomers, and silicone-based elastomers. These may be used alone or in combination of two or more.

[0092] When an elastomer is used, the blending amount may be 1 to 50 parts by mass or 5 to 30 parts by mass per 100 parts by mass of component (A). When the blending amount of elastomer is 1 part by mass or more, the thermal shock resistance of the cured film tends to be improved, while when the blending amount is 50 parts by mass or less, the resolution and heat resistance of the obtained cured film tend not to decrease, and the compatibility and dispersibility with other components tend not to decrease.

[0093] (solubility enhancer) By incorporating a dissolution promoter into the photosensitive resin composition, the dissolution rate of the exposed area during development with an alkaline aqueous solution can be increased, thereby improving sensitivity and resolution. Conventional dissolution promoters can be used. Examples of dissolution promoters include compounds having a carboxy group, sulfonic acid, or sulfonamide group. When a dissolution promoter is used, its amount can be determined based on the dissolution rate in the alkaline aqueous solution, and can be, for example, 0.01 to 30 parts by mass per 100 parts by mass of component (A).

[0094] (dissolution inhibitors) Dissolution inhibitors are compounds that inhibit the solubility of component (A) in an alkaline aqueous solution and are used to control the residual film thickness, development time, and contrast. Examples of dissolution inhibitors include diphenyliodonium nitrate, bis(p-tert-butylphenyl)iodonium nitrate, diphenyliodonium bromide, diphenyliodonium chloride, and diphenyliodonium iodide. When a dissolution inhibitor is used, the amount may be 0.01 to 20 parts by mass, 0.01 to 15 parts by mass, or 0.05 to 10 parts by mass per 100 parts by mass of component (A), taking into account the tolerance range for sensitivity and development time.

[0095] (coupling agent) By incorporating a coupling agent into the photosensitive resin composition, the adhesiveness of the patterned cured film formed to the substrate can be improved. Examples of coupling agents include organic silane compounds and aluminum chelate compounds.

[0096] Examples of the organic silane compound include vinyltriethoxysilane, γ-glycidoxypropyltriethoxysilane, γ-methacryloxypropyltrimethoxysilane, ureapropyltriethoxysilane, methylphenylsilanediol, ethylphenylsilanediol, n-propylphenylsilanediol, isopropylphenylsilanediol, n-butylphenylsilanediol, isobutylphenylsilanediol, tert-butylphenylsilanediol, diphenylsilanediol, ethylmethylphenylsilanol, n-propylmethylphenylsilanol, isopropylmethylphenylsilanol, n-butylmethylphenylsilanol, isobutylmethylphenylsilanol, tert-butylmethylphenylsilanol, ethyl n-propylphenylsilanol, ethylisopropylphenylsilanol, n-butylethylphenylsilanol, and isobutylmethylphenylsilanol. butylethylphenylsilanol, tert-butylethylphenylsilanol, methyldiphenylsilanol, ethyldiphenylsilanol, n-propyldiphenylsilanol, isopropyldiphenylsilanol, n-butyldiphenylsilanol, isobutyldiphenylsilanol, tert-butyldiphenylsilanol, phenylsilanetriol, 1,4-bis(trihydroxysilyl)benzene, 1,4-bis(methyldihydroxysilyl)benzene, 1,4-bis(ethyldihydroxysilyl)benzene, 1,4-bis(propyldihydroxysilyl)benzene, 1,4-bis(butyldihydroxysilyl)benzene, 1,4-bis(dimethylhydroxysilyl)benzene, 1,4-bis(diethylhydroxysilyl)benzene, 1,4-bis(dipropylhydroxysilyl)benzene, and 1,4-bis(dibutylhydroxysilyl)benzene.

[0097] When a coupling agent is used, the amount added may be 0.1 to 20 parts by mass or 0.5 to 10 parts by mass per 100 parts by mass of the component (A).

[0098] (Surfactant or leveling agent) Adding a surfactant or leveling agent to a photosensitive resin composition can improve coatability. Specifically, for example, the inclusion of a surfactant or leveling agent can prevent striations (uneven film thickness) and improve developability. Examples of surfactants or leveling agents include polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl ether, and polyoxyethylene octylphenol ether. Commercially available surfactants or leveling agents include Megafac F171, F173, and R-08 (manufactured by DIC Corporation, trade names), Fluorad FC430 and FC431 (manufactured by Sumitomo 3M Limited, trade names), and organosiloxane polymers KP341, KBM303, KBM403, and KBM803 (manufactured by Shin-Etsu Chemical Co., Ltd., trade names).

[0099] When a surfactant or leveling agent is used, the amount added may be 0.001 to 5 parts by mass or 0.01 to 3 parts by mass per 100 parts by mass of the component (A).

[0100] (solvent) The photosensitive resin composition contains a solvent for dissolving or dispersing each component, which makes it easy to apply the composition onto a substrate and enables the formation of a coating film of uniform thickness.

[0101] Examples of the solvent 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. The solvents can be used alone or in combination of two or more.

[0102] The amount of the solvent to be added is not particularly limited, but it is preferable to adjust the ratio of the solvent in the photosensitive resin composition to 20 to 90 mass %.

[0103] The photosensitive resin composition according to this embodiment can be developed using an alkaline aqueous solution such as sodium hydroxide, potassium hydroxide, sodium silicate, ammonia, ethylamine, diethylamine, triethylamine, triethanolamine, tetramethylammonium hydroxide (TMAH), etc. By using the photosensitive resin composition according to this embodiment, it is possible to form a resist pattern with a good shape, good adhesion, and heat resistance, with sufficiently high sensitivity and resolution.

[0104] [Method of manufacturing patterned cured film] The method for producing a patterned cured film (resist pattern) according to this embodiment includes the steps of applying the above-described photosensitive resin composition to a part or the entire surface of a substrate and drying it to form a resin film (application and drying (film formation) step), exposing at least a part of the resin film to light (exposure step), developing the exposed resin film to form a patterned resin film (development step), and heating the patterned patterned resin film (photosensitive resin film). Each step will be described below.

[0105] (Coating and drying (film formation) process) First, the photosensitive resin composition according to this embodiment is applied to a substrate and dried to form a resin film. In this process, the photosensitive resin composition is spin-coated onto a substrate such as a glass substrate, semiconductor, metal oxide insulator (e.g., TiO2, SiO2), or silicon nitride using a spinner or the like to form a coating film. The substrate on which this coating film has been formed is then dried using a hot plate, oven, or the like. There are no particular restrictions on the drying temperature or drying time, but drying at 80 to 140°C for 1 to 7 minutes is sufficient. This results in the formation of a photosensitive resin film on the substrate.

[0106] (Exposure process) Next, in the exposure step, the resin film formed on the substrate is irradiated with actinic rays such as ultraviolet light, visible light, or radiation through a mask. In the above-mentioned photosensitive resin composition, component (A) has high transparency to i-rays, so i-ray irradiation can be used suitably. After exposure, post-exposure baking (PEB) can also be performed as necessary. The post-exposure baking temperature is preferably 70 to 140°C, and the post-exposure baking time is preferably 1 to 5 minutes.

[0107] (Developing process) In the development step, the exposed portions of the resin film after the exposure step are removed with a developer, thereby patterning the resin film and obtaining a patterned resin film. Suitable developers include aqueous alkaline solutions such as sodium hydroxide, potassium hydroxide, sodium silicate, ammonia, ethylamine, diethylamine, triethylamine, triethanolamine, and tetramethylammonium hydroxide (TMAH). The base concentration of these aqueous solutions may be 0.1 to 10% by mass. Alcohols or surfactants may also be added to the developer. These may be blended in amounts of 0.01 to 10 parts by mass or 0.1 to 5 parts by mass, respectively, per 100 parts by mass of the developer. When developing using a developer, the developer is applied to the resin film by, for example, shower development, spray development, immersion development, or puddle development, and then allowed to stand at 18 to 40°C for 30 to 360 seconds. After standing, the patterned resin film is washed with water and spin-dried.

[0108] (heat treatment process) Next, in the heat treatment step, the patterned resin film is heat treated to form a patterned cured film (resist pattern). The heating temperature in the heat treatment step may be 250°C or less, 225°C or less, or 140 to 200°C, in order to sufficiently prevent heat damage to the electronic device.

[0109] The heat treatment can be performed using an oven such as a quartz tube furnace, a hot plate, a rapid thermal annealer, a vertical diffusion furnace, an infrared curing oven, an electron beam curing oven, or a microwave curing oven. The heat treatment can be performed in either air or an inert atmosphere such as nitrogen, but nitrogen is preferred because it can prevent oxidation of the pattern. The above-mentioned heating temperature range is lower than conventional heating temperatures, minimizing damage to the substrate and electronic device. Therefore, by using the method for producing a patterned cured film according to this embodiment, electronic devices can be produced with a high yield. This also leads to energy savings in the process. Furthermore, the photosensitive resin composition according to this embodiment exhibits small volume shrinkage (cure shrinkage) during the heat treatment process, which is common in photosensitive polyimides and the like, preventing a decrease in dimensional accuracy.

[0110] The heat treatment time in the heat treatment step may be any time long enough to cure the photosensitive resin composition, but is preferably about 5 hours or less in terms of work efficiency.

[0111] The heat treatment can be performed using a microwave curing device or a variable frequency microwave curing device, in addition to the oven described above. By using these devices, it is possible to effectively heat only the resin film while maintaining the temperatures of the substrate and electronic device at a desired temperature (for example, 200°C or less).

[0112] In a variable-frequency microwave curing device, microwaves are irradiated in pulses while changing their frequency, preventing standing waves and allowing the substrate surface to be heated uniformly. Furthermore, when the substrate includes metal wiring, such as electronic components described below, irradiating microwaves in pulses while changing their frequency can prevent discharges from the metal and protect the electronic components from damage. Furthermore, when heating using variable-frequency microwaves, the physical properties of the cured film are less likely to deteriorate even if the curing temperature is lowered compared to when using an oven (see J. Photopolym. Sci. Technol., 18, 327-332 (2005)).

[0113] The frequency of the variable-frequency microwave is in the range of 0.5 to 20 GHz, but may be in the range of 1 to 10 GHz or 2 to 9 GHz in practice. It is desirable to continuously change the frequency of the microwave to be irradiated, but in practice the frequency is changed stepwise during irradiation. In this case, the shorter the irradiation time of the microwave of a single frequency, the less likely it is to cause standing waves, discharge from metal, etc., so the microwave irradiation time is preferably 1 millisecond or less, and more preferably 100 microseconds or less.

[0114] The output of the microwaves to be irradiated varies depending on the size of the device or the amount of the object to be heated, but is generally in the range of 10 to 2000 W, and in practice may be 100 to 1000 W, 100 to 700 W, or 100 to 500 W. If the output is 10 W or higher, the object to be heated can be easily heated in a short time, and if it is 2000 W or lower, a sudden rise in temperature is unlikely to occur.

[0115] It is preferable to irradiate microwaves by turning them on and off in a pulsed manner. By irradiating microwaves in a pulsed manner, the set heating temperature can be maintained and damage to the cured film and substrate can be avoided, which is preferable. The duration of each pulsed microwave irradiation varies depending on the conditions, but is preferably approximately 10 seconds or less.

[0116] According to the method for producing a patterned cured film as described above, a patterned cured film having sufficiently high sensitivity and resolution and good heat resistance can be obtained. The patterned cured film according to this embodiment can be used as an interlayer insulating layer or a surface protective layer of a semiconductor device.

[0117] [Semiconductor device manufacturing process] As an example of the method for producing a patterned cured film (resist pattern) according to this embodiment, a manufacturing process for a semiconductor device will be described with reference to the drawings. Figures 1 to 5 are schematic cross-sectional views showing one embodiment of the manufacturing process for a semiconductor device having a multilayer wiring structure.

[0118] First, prepare a structure 100 shown in Fig. 1. The structure 100 includes a semiconductor substrate 1 such as a Si substrate having circuit elements, a protective film 2 such as a silicon oxide film having a predetermined pattern that exposes the circuit elements and covers the semiconductor substrate 1, a first conductor layer 3 formed on the exposed circuit elements, and an interlayer insulating layer 4 made of a polyimide resin or the like that is formed on the protective film 2 and the first conductor layer 3 by a method such as spin coating.

[0119] Next, a photosensitive resin layer 5 having a window portion 6A is formed on the interlayer insulating layer 4, thereby obtaining the structure 200 shown in Figure 2. The photosensitive resin layer 5 is formed by applying a photosensitive resin such as a chlorinated rubber, phenol novolac, polyhydroxystyrene, or polyacrylic ester by spin coating. The window portion 6A is formed by known photoetching techniques so that a predetermined portion of the interlayer insulating layer 4 is exposed.

[0120] After etching the interlayer insulating layer 4 to form the window portion 6B, the photosensitive resin layer 5 is removed, yielding the structure 300 shown in FIG. 3. The interlayer insulating layer 4 can be etched by dry etching using a gas such as oxygen or carbon tetrafluoride. This etching selectively removes the interlayer insulating layer 4 in the portion corresponding to the window portion 6A, resulting in an interlayer insulating layer 4 provided with the window portion 6B so that the first conductor layer 3 is exposed. Next, the photosensitive resin layer 5 is removed using an etching solution that corrodes only the photosensitive resin layer 5 without corroding the first conductor layer 3 exposed from the window portion 6B.

[0121] Furthermore, a second conductor layer 7 is formed in the portion corresponding to the window portion 6B, thereby obtaining the structure 400 shown in FIG. 4. A known photolithography technique can be used to form the second conductor layer 7. This allows electrical connection between the second conductor layer 7 and the first conductor layer 3.

[0122] Finally, a surface protection layer 8 is formed on the interlayer insulating layer 4 and the second conductor layer 7 to obtain the semiconductor device 500 shown in FIG. 5 . In this embodiment, the surface protection layer 8 is formed as follows: First, the photosensitive resin composition according to the above embodiment is applied to the interlayer insulating layer 4 and the second conductor layer 7 by spin coating, and then dried to form a resin film. Next, the resin film is irradiated with light through a mask having a pattern corresponding to the window portion 6C drawn thereon, and then developed with an alkaline aqueous solution to pattern the resin film. The resin film is then cured by heating to form a film serving as the surface protection layer 8. This surface protection layer 8 protects the first conductor layer 3 and the second conductor layer 7 from external stress, alpha rays, and the like, and the resulting semiconductor device 500 has excellent reliability.

[0123] Although the above embodiment shows a method for manufacturing a semiconductor device having a two-layer wiring structure, when forming a multilayer wiring structure of three or more layers, the above steps can be repeated to form each layer. That is, by repeating the steps of forming the interlayer insulating layer 4 and the steps of forming the surface protective layer 8, it is possible to form a multilayer pattern. Furthermore, in the above example, not only the surface protective layer 8 but also the interlayer insulating layer 4 can be formed using the photosensitive resin composition according to this embodiment.

[0124] [Electronic Components] Next, an electronic component according to this embodiment will be described. The electronic component according to this embodiment has a patterned cured film formed by the above-described manufacturing method as an interlayer insulating layer or a surface protective layer. Electronic components include semiconductor devices, multilayer wiring boards, various electronic devices, and the like. Specifically, the patterned cured film can be used as a surface protective layer, an interlayer insulating layer, an interlayer insulating layer of a semiconductor device, or the like. The electronic component according to this embodiment is not particularly limited except that it has a surface protective layer or an interlayer insulating layer formed using the above-described photosensitive resin composition, and can have various structures.

[0125] Furthermore, the photosensitive resin composition described above has excellent stress relaxation properties, adhesive properties, etc., and can therefore be used as various structural materials in various packages of various structures that have been developed recently. Figures 6 and 7 show the cross-sectional structure of an example of such a semiconductor device.

[0126] Fig. 6 is a schematic cross-sectional view showing a wiring structure as one embodiment of a semiconductor device. The semiconductor device 600 shown in Fig. 6 includes a silicon chip 23, an interlayer insulating layer 11 provided on one side of the silicon chip 23, an Al wiring layer 12 formed on the interlayer insulating layer 11 and having a pattern including pad portions 15, an insulating layer 13 (e.g., a P-SiN layer) and a surface protective layer 14 sequentially stacked on the interlayer insulating layer 11 and the Al wiring layer 12 while forming openings above the pad portions 15, an island-shaped core 18 disposed on the surface protective layer 14 near the opening, and a rewiring layer 16 extending on the surface protective layer 14 so as to contact the pad portions 15 within the openings of the insulating layer 13 and the surface protective layer 14 and to contact the surface of the core 18 opposite to the surface protective layer 14. The semiconductor device 600 further includes a cover coat layer 19 formed to cover the surface protection layer 14, the core 18, and the rewiring layer 16, with an opening formed in the portion of the rewiring layer 16 above the core 18; a conductive ball 17 connected to the rewiring layer 16 in the opening of the cover coat layer 19 with a barrier metal 20 sandwiched therebetween; a collar 21 for holding the conductive ball; and an underfill 22 provided on the cover coat layer 19 around the conductive ball 17. The conductive ball 17 is used as an external connection terminal and is made of solder, gold, or the like. The underfill 22 is provided to relieve stress when the semiconductor device 600 is mounted.

[0127] Fig. 7 is a schematic cross-sectional view showing a wiring structure as one embodiment of a semiconductor device. In the semiconductor device 700 of Fig. 7, an Al wiring layer (not shown) and pad portions 15 of the Al wiring layer are formed on a silicon chip 23, an insulating layer 13 is formed thereon, and a surface protection layer 14 of the element is further formed thereon. A rewiring layer 16 is formed on the pad portions 15, and this rewiring layer 16 extends to the top of connection portions 24 with the conductive balls 17. Furthermore, a cover coat layer 19 is formed on the surface protection layer 14. The rewiring layer 16 is connected to the conductive balls 17 via a barrier metal 20.

[0128] 6 and 7, the above-mentioned photosensitive resin composition can be used as a material for forming not only the interlayer insulating layer 11 and the surface protective layer 14, but also the cover coat layer 19, the core 18, the collar 21, the underfill 22, etc. A cured product using the above-mentioned photosensitive resin composition has excellent adhesion to metal layers such as the Al wiring layer 12 and the rewiring layer 16, and to sealing materials, and also has a high stress relaxation effect, so that a semiconductor device using this cured product for the cover coat layer 19, the core 18, the collar 21 such as solder, the underfill 22 used in flip chips, etc. will have extremely excellent reliability.

[0129] The photosensitive resin composition according to this embodiment is particularly suitable for use in the surface protection layer 14 and / or cover coat layer 19 of a semiconductor device having a rewiring layer 16 in Figures 6 and 7. The thickness of the surface protection layer or cover coat layer may be, for example, 3 to 20 µm or 5 to 15 µm.

[0130] By using the photosensitive resin composition according to this embodiment, curing can be achieved using low-temperature heating at 200°C or below, whereas the conventional heating process required 300°C or higher. Furthermore, the photosensitive resin composition according to this embodiment exhibits small volume shrinkage (cure shrinkage) during the heating process, as seen with photosensitive polyimides and the like, thereby preventing a decrease in dimensional accuracy. The patterned cured film formed from the photosensitive resin composition according to this embodiment has a high glass transition temperature, and therefore serves as a surface protection layer with excellent heat resistance. As a result, highly reliable electronic components such as semiconductor devices can be produced at high yields. [Example]

[0131] The present invention will be described in more detail below with reference to examples, although the present invention is not limited to the following examples.

[0132] The materials used to prepare the photosensitive resin compositions of the Examples and Comparative Examples are shown below.

[0133] (Component (A): alkali-soluble resin) As the component (A), P-1 to P-9 were prepared. The Mw and Tg of P-1 to P-9 are shown in Table 1.

[0134] (P-1) Cresol novolak resin (m-cresol / p-cresol (molar ratio) = 60 / 40, Mw = 12,000, Tg = 165°C, product name "EP4020G", manufactured by Asahi Organic Chemicals Co., Ltd.) (P-2) Cresol novolak resin (m-cresol / p-cresol (molar ratio) = 60 / 40, Mw = 4500, Tg = 150°C, product name "EP4080G", manufactured by Asahi Organic Chemicals Co., Ltd.)

[0135] (P-3) A flask was charged with 35.6 g of 4-hydroxyphenyl methacrylate, 78.0 g of 2-hydroxyethyl methacrylate, 20.0 g of N-acryloyloxyethylhexahydrophthalimide (trade name "M-140", manufactured by Toagosei Co., Ltd.), 300 g of N,N-dimethylacetamide (DMAC), and 6.43 g of azoisobutyronitrile (AIBN), and the mixture was reacted for 6 hours at 80°C under a nitrogen atmosphere. After adding 200 g of methanol, the mixture was slowly added dropwise to 1000 g of ion-exchanged water, and the precipitated polymer was filtered and dried to obtain P-3.

[0136] (P-4) A flask was charged with 44.5 g of 4-hydroxyphenyl methacrylate, 39.0 g of 2-hydroxyethyl methacrylate, 45.0 g of N-acryloyloxyethylhexahydrophthalimide, 300 g of DMAC, and 6.43 g of AIBN, and the mixture was reacted for 6 hours at 80°C under a nitrogen atmosphere. After adding 200 g of methanol, the mixture was slowly added dropwise to 1000 g of ion-exchanged water, and the precipitated polymer was filtered and dried to obtain P-4.

[0137] (P-5) A flask was charged with 43.0 g of methacrylic acid, 39.0 g of 2-hydroxyethyl methacrylate, 20.0 g of N-acryloyloxyethylhexahydrophthalimide, 300 g of DMAC, and 5.10 g of AIBN, and the mixture was reacted for 6 hours at 80°C under a nitrogen atmosphere. After adding 200 g of methanol, the mixture was slowly added dropwise to 1000 g of ion-exchanged water, and the precipitated resin was filtered and dried to obtain P-5.

[0138] (P-6) A 300 mL flask equipped with a stirrer, thermometer, nitrogen replacement device (nitrogen inlet tube), and reflux condenser with a water receiver was charged with 14.64 g (0.04 mol) of the amine components 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane (trade name "BIS-AP-AF" manufactured by Central Glass Co., Ltd.), 19.48 g (0.045 mol) of polyoxypropylenediamine (trade name "D-400" manufactured by BASF), and 2.485 g (0.01 mol) of 3,3'-(1,1,3,3-tetramethyldisiloxane-1,3-diyl)bispropylamine (trade name "BY16-871EG" manufactured by Dow Corning Toray Co., Ltd.), and 80 g of the solvent N-methyl-2-pyrrolidone (NMP), and the mixture was stirred to dissolve the amine components in the solvent. While the flask was cooled in an ice bath, 31 g (0.1 mol) of 4,4'-oxydiphthalic dianhydride (ODPA) was added little by little to the solution in the flask. After the addition was completed, the solution was heated to 180°C while blowing in nitrogen gas and kept at that temperature for 5 hours to obtain an NMP solution of P-6.

[0139] (P-7) A flask equipped with a stirrer, thermometer, nitrogen purge system (nitrogen inlet tube), and reflux condenser with a water receiver was charged with 7.15 g (0.025 mol) of the diamine 5,5'-methylenebis(anthranilic acid) (trade name "MBAA", Wakayama Seika Kogyo Co., Ltd., molecular weight 286), 25.98 g (0.06 mol) of "D-400 (polyoxypropylenediamine)", and 2.48 g (0.01 mol) of "BY16-871EG (3,3'-(1,1,3,3-tetramethyldisiloxane-1,3-diyl)bispropylamine)", and 110 g of NMP solvent. The mixture was stirred to dissolve the diamine in the solvent. While the flask was cooled in an ice bath, 31 g (0.1 mol) of ODPA was added in small portions to the solution in the flask. After the addition was completed, the temperature of the solution was raised to 180° C. while blowing nitrogen gas into it, and the temperature was maintained for 5 hours to obtain an NMP solution of P-7.

[0140] (P-8) A flask was charged with 44.5 g of 4-hydroxyphenyl methacrylate, 39.0 g of 2-hydroxyethyl methacrylate, 45.0 g of methyl methacrylate, 300 g of DMAC, and 6.43 g of AIBN, and the mixture was reacted for 6 hours at 80°C under a nitrogen atmosphere. After adding 200 g of methanol, the mixture was slowly added dropwise to 1000 g of ion-exchanged water, and the precipitated polymer was filtered and dried to obtain P-8.

[0141] (P-9) 55 g of ethyl lactate was weighed into a 100 mL three-neck flask equipped with a stirrer, a nitrogen inlet tube, and a thermometer, and separately weighed polymerizable monomers (34.7 g of n-butyl acrylate (BA), 2.2 g of lauryl acrylate (LA), 3.9 g of acrylic acid (AA), 2.6 g of hydroxybutyl acrylate (HBA), 1.7 g of 1,2,2,6,6-pentamethylpiperidin-4-yl methacrylate (trade name "FA-711MM", manufactured by Hitachi Chemical Co., Ltd.), and 0.29 g of AIBN were added. The mixture was stirred at room temperature (25°C) at approximately 160 rpm (min -1While stirring at a rotation speed of 1000 rpm, nitrogen gas was passed through at a flow rate of 400 mL / min for 30 minutes to remove dissolved oxygen. The nitrogen gas flow was then stopped, the flask was sealed, and the temperature was raised to 65°C in a thermostatic water bath over approximately 25 minutes. The same temperature was maintained for 10 hours to carry out the polymerization reaction, yielding a solution of acrylic resin P-9 in ethyl lactate. The polymerization rate was 99%.

[0142] [Table 1]

[0143] ((B) component: thermosetting resin) (B-1): 4,4',4''-Ethylidene tris[2,6-(methoxymethyl)phenol] (trade name "HMOM-TPHAP", manufactured by Honshu Chemical Industry Co., Ltd.) (B-2): Bisphenol A bis(triethylene glycol glycidyl ether) ether (product name "BEO-60E", manufactured by New Japan Chemical Co., Ltd.)

[0144] (Component (C): Photosensitizer) (C-1): 1-naphthoquinone-2-diazide-5-sulfonic acid ester of tris(4-hydroxyphenyl)methane (esterification rate: approximately 95%)

[0145] (Component (D): a low molecular weight compound having a phenolic hydroxyl group) (D-1): 1,1-bis(4-hydroxyphenyl)-1-[4-{1-(4-hydroxyphenyl)-1-methylethyl}phenyl]ethane (trade name "TrsP-PA-MF", manufactured by Honshu Chemical Industry Co., Ltd.)

[0146] Components (A) to (D) were mixed in the amounts (parts by mass) shown in Table 2, 120 parts by mass of ethyl lactate as a solvent, and 2 parts by mass of a 50% by mass ethanol solution of 3-glycidoxypropyltriethoxysilane (trade name "KBE-403", manufactured by Shin-Etsu Chemical Co., Ltd.) as a coupling agent. The mixture was filtered under pressure using a polytetrafluoroethylene resin filter with 3 μm pores to prepare a photosensitive resin composition.

[0147] [Table 2]

[0148] <Evaluation of Photosensitive Resin Composition> The photosensitive resin composition was evaluated as follows, and the results are shown in Table 3.

[0149] (Preparation of evaluation samples) The photosensitive resin composition was applied by a spin coater to a 6-inch silicon wafer with copper formed on the surface by sputtering so that the film thickness after curing would be 10 μm, and the wafer was heated on a hot plate at 100°C for 5 minutes to form a resin film. A high-precision parallel exposure machine (product name "EXM-1172-B-∞", manufactured by Oak Manufacturing Co., Ltd.) was used to expose the resin film to 1000 mJ / cm through a photomask designed to obtain a strip pattern with a width of 10 mm. 2 The resin film was exposed under these conditions and developed using a 2.38% by mass TMAH aqueous solution to obtain a strip pattern of the resin film. The strip pattern was heated under nitrogen at 200°C for 2 hours, and then immersed in a copper etching solution to produce strip samples of the cured film with a thickness of 10 μm and a width of 10 mm.

[0150] (fatigue fracture resistance) Using a special autograph equipped with a thermostatic chamber (AG-1kNXplus) manufactured by Shimadzu Corporation, fatigue tests were carried out on the above strip samples under the following conditions. Condition (1): The strip sample is repeatedly pulled (0 to 100 MPa) under the conditions of a set temperature of 25°C, a chuck distance of 20 mm, a test speed of 5 mm / min, and a repeated load stress of 100 MPa. Condition (2): The strip sample is repeatedly pulled (0 to 120 MPa) under the conditions of a set temperature of -55°C, a chuck distance of 20 mm, a test speed of 5 mm / min, and a repeated load stress of 120 MPa.

[0151] Measurements were performed three times under each condition, and fatigue fracture resistance was evaluated as follows: if the average number of tensile cycles at which the strip sample broke exceeded 1,000, it was given an "A"; if it was between 100 and 1,000, it was given a "B"; and if fracture occurred in less than 100 cycles, it was given a "C."

[0152] (stretch) In the examples, after 100 cycles of fatigue testing under the above conditions, strip samples were subjected to tension measurement using a special autograph with a constant temperature bath (AG-1kNXplus) manufactured by Shimadzu Corporation at a set temperature of 25°C, a chuck distance of 20 mm, and a test speed of 5 mm / min, to measure the elongation at break.

[0153] (yield stress) In the above tensile test, the stress value at the intersection of the tangent line to the plot showing 5% elongation and the tangent line to the plot showing 15% elongation was taken as the yield stress.

[0154] (Young's modulus) In the above tensile test, Young's modulus was calculated from the slope of the curve obtained by plotting the elongation rate on the horizontal axis and the stress on the vertical axis in the elongation range of 0 to 5%.

[0155] The strip samples prepared in the comparative examples broke in less than 100 cycles of the fatigue test, so the elongation, yield stress, and Young's modulus of the comparative examples were measured using strip samples that were not subjected to the fatigue test.

[0156] (glass transition temperature) The viscoelasticity of the strip sample was measured using a dynamic viscoelasticity measuring device manufactured by UBM Corporation, with a chuck distance of 20 mm, a frequency of 10 Hz, and a temperature rise rate of 5°C / min in the temperature range of 40 to 260°C, and the temperature showing the maximum value of tan δ was taken as the glass transition temperature (Tg).

[0157] (Adhesion rate) The photosensitive resin composition was applied to the surface of an electrolytically plated copper substrate using a spin coater so that the cured film thickness would be 10 μm, and then heated on a hot plate at 120°C for 3 minutes to form a resin film. The resin film was then cured by heating at 200°C for 2 hours in a nitrogen atmosphere to prepare a sample for adhesion evaluation.

[0158] The adhesion rate evaluation sample was subjected to a temperature cycle test 200 times under atmospheric pressure air conditions, with temperatures ranging from -65 to 150°C and a 15-minute pause, starting and ending at -65°C. The test was then cut into a grid using the cross-cut method specified in JIS K 5600-5-6. Tape with an adhesive strength of 10±1 N per 25 mm width was then applied to 25 grids (cured film). The tape was then peeled off vertically in 0.5 to 1.0 seconds within 5 minutes of application. The number of grids where the cured film had peeled along the edges of the cut or at the intersections was counted, and the percentage of grids (cured film) that remained attached to the electroplated copper substrate (adhesion rate) was calculated. Adhesion rates were evaluated as follows: 100% adhesion rate ("A"), 75% or greater but less than 100% adhesion rate ("B"), and less than 75% adhesion rate ("C").

[0159] (Reliability) A photosensitive resin composition was applied to a 400 μm-thick, 8-inch silicon wafer using a spin coater to a cured film thickness of 10 μm. The wafer was then heated on a hot plate at 100°C for 5 minutes, and then heated under nitrogen at 200°C for 2 hours to produce a first-layer cured film. A seed layer was formed using a sputtering device to form 200 nm of Cu on 50 nm of Ti, and a resist material was patterned and electroplated to a copper thickness of 5 μm. The resist material was stripped with NMP, and the Cu and Ti were removed by etching to produce a 350 μm-diameter first-layer copper pattern. A photomask designed to leave a 70% copper residual ratio by a copper mesh pattern was used for the areas other than the copper pattern.

[0160] Next, the photosensitive resin composition was applied by a spin coater so that the film thickness after curing on the copper would be 5 μm, and after heating on a hot plate at 100°C for 5 minutes, it was exposed to 600 mJ / cm using a stepper exposure machine (Sc6k manufactured by Therma Precision Co., Ltd.) through a photomask designed to form an 80 μm diameter opening in the center of the first layer copper pattern with a diameter of 350 μm. 2 After exposure, the film was developed with a 2.38% by mass aqueous solution of TMAH to create openings with a diameter of 80 μm, and then heated under nitrogen at 200° C. for 2 hours to form a second cured film.

[0161] A seed layer was formed using a sputtering system, forming 200 nm of Cu on 50 nm of Ti. A resist material was patterned using a photomask designed to create a 240 μm diameter opening in the center of a 350 μm diameter first-layer copper pattern. Electroplating was then performed to a copper thickness of 5 μm. The resist material was stripped with NMP, and the Cu and Ti were removed by etching to create a 240 μm diameter second-layer copper pattern. A photomask designed to leave a copper mesh pattern with a 30% copper residual ratio was used in areas other than the copper pattern. Flux was applied to the 240 μm diameter second-layer copper pattern, and 250 μm diameter solder balls (Eco Solder Ball SM705, manufactured by Senju Metal Industry Co., Ltd.) were mounted. Reflow was performed under nitrogen atmosphere under profile conditions conforming to JEDEC (Semiconductor Technology Association; J-STD-020D). The package was then flux-cleaned to obtain a reliability evaluation package.

[0162] A temperature cycle test was conducted on the above package under the JESD22-A104 condition B standard, which involves repeating 1,000 cycles of -55°C for 15 minutes and 125°C for 15 minutes, and 300 locations on the sidewall of the 240μm diameter second-layer copper pattern were observed. Package reliability (thermal shock reliability) was evaluated by assigning an "A" if cracks occurred in less than 5%, a "B" if cracks occurred in 5-20%, and a "C" if cracks occurred in more than 20%.

[0163] [Table 3]

[0164] As shown in Table 3, the fatigue tests under conditions (1) and (2) correlate with package reliability, and it can be confirmed that by evaluating the fatigue fracture resistance of the cured film, it is possible to easily evaluate thermal shock reliability (packaging reliability), which requires time for sample preparation and evaluation, in a short time. By using a photosensitive resin composition selected in the fatigue test and having a fatigue fracture resistance of 100 cycles or more, it is possible to form a patterned cured film with excellent thermal shock reliability (packaging reliability), and semiconductor devices using this film will also have excellent thermal shock reliability. [Explanation of symbols]

[0165] 1...semiconductor substrate, 2...protective film, 3...first conductor layer, 4...interlayer insulating layer, 5...photosensitive resin layer, 6A, 6B, 6C...window portion, 7...second conductor layer, 8...surface protective layer, 11...interlayer insulating layer, 12...Al wiring layer, 13...insulating layer, 14...surface protective layer, 15...pad portion, 16...rewiring layer, 17...conductive ball, 18...core, 19...cover coat layer, 20...barrier metal, 21...collar, 22...underfill, 23...silicon chip, 24...connection portion, 100, 200, 300, 400...structure, 500...semiconductor device, 600...semiconductor device, 700...semiconductor device.

Claims

1. A photosensitive resin composition used in a curing step in which a cured film is obtained by exposure to light at 100 to 2000 mJ / cm 2 and heat treatment at 150 to 250°C for 1 to 3 hours under nitrogen, the cured film has a property that, when a strip sample having a film thickness of 10 μm and a width of 10 mm is subjected to a fatigue test in which the strip sample is repeatedly pulled under the conditions of a set temperature of 25° C., a chuck distance of 20 mm, a test speed of 5 mm / min, and a repeated load stress of 100 MPa, the strip sample is pulled for 100 cycles or more until it breaks, the photosensitive resin composition comprises (A) an alkali-soluble resin, (B) a thermosetting resin, (C) a photosensitizer, and (D) a low molecular weight compound having a phenolic hydroxyl group, the alkali-soluble resin (A) comprising an alkali-soluble resin having an imide group and an alkali-soluble resin not having an imide group; the alkali-soluble resin having an imide group is an acrylic polymer obtained by polymerizing an N-acryloyloxyethylhexahydrophthalimide or N-methacryloyloxyethylhexahydrophthalimide compound, or an alkali-soluble polyimide; the alkali-soluble resin having no imide group is a novolak resin or a phenolic resin, a content of the alkali-soluble resin having an imide group in the photosensitive resin composition is 10 mass % or more based on the total amount of the alkali-soluble resin (A).

2. 2. The photosensitive resin composition according to claim 1, wherein a strip sample after 100 cycles of the fatigue test is subjected to a tensile test in which the strip sample is pulled under conditions of a set temperature of 25°C, a chuck distance of 20 mm, and a test speed of 5 mm / min, and the elongation at break of the strip sample is 10 to 60%.

3. 3. The photosensitive resin composition according to claim 2, wherein the yield stress of the strip sample in the tensile test is 120 to 200 MPa.

4. 4. The photosensitive resin composition according to claim 2, wherein the Young's modulus of the strip sample in the tensile test is 0.5 to 2.8 GPa.

5. The photosensitive resin composition according to any one of claims 1 to 4, wherein the cured film has a glass transition temperature of 150°C or higher.

6. A photosensitive resin composition used in a curing step in which a cured film is obtained by exposing to light at 100 to 2000 mJ / cm 2 and then heat-treating in nitrogen at 150 to 250°C for 1 to 3 hours, the cured film has the property that, when a strip sample having a film thickness of 10 μm and a width of 10 mm is subjected to a fatigue test in which the strip sample is repeatedly pulled under the conditions of a set temperature of −55° C., a chuck distance of 20 mm, a test speed of 5 mm / min, and a repeated load stress of 120 MPa, the strip sample is pulled for 100 cycles or more until it breaks, the photosensitive resin composition comprises (A) an alkali-soluble resin, (B) a thermosetting resin, (C) a photosensitizer, and (D) a low molecular weight compound having a phenolic hydroxyl group, the alkali-soluble resin (A) comprising an alkali-soluble resin having an imide group and an alkali-soluble resin not having an imide group; the alkali-soluble resin having an imide group is an acrylic polymer obtained by polymerizing an N-acryloyloxyethylhexahydrophthalimide or N-methacryloyloxyethylhexahydrophthalimide compound, or an alkali-soluble polyimide; the alkali-soluble resin having no imide group is a novolak resin or a phenolic resin, a content of the alkali-soluble resin having an imide group in the photosensitive resin composition is 10 mass % or more based on the total amount of the alkali-soluble resin (A).

7. 7. The photosensitive resin composition according to claim 6, wherein a strip sample after 100 cycles of the fatigue test is subjected to a tensile test in which the strip sample is pulled under conditions of a set temperature of 25°C, a chuck distance of 20 mm, and a test speed of 5 mm / min, and the elongation at break of the strip sample is 10 to 60%.

8. 8. The photosensitive resin composition according to claim 7, wherein the yield stress of the strip sample in the tensile test is 120 to 200 MPa.

9. 9. The photosensitive resin composition according to claim 7, wherein the Young's modulus of the strip sample in the tensile test is 0.5 to 2.8 GPa.

10. The photosensitive resin composition according to any one of claims 6 to 9, wherein the cured film has a glass transition temperature of 150°C or higher.

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