Photosensitive resin composition

Abstract

To provide a photosensitive resin composition which enable formation of a cured film that enables development in an alkali aqueous solution, prevents generation of cracks when cured at 250°C or lower, and has high mechanical and thermal impact reliability.SOLUTION: There is provided a photosensitive resin composition in which a strip sample of a cured film with a film thickness of 10 μm and a width of 10 mm is manufactured by exposing a resin film of the photosensitive resin composition with light of 100 to 2,000 mJ / cm2, subjecting the resin film to heat treatment under nitrogen at 150 to 250°C for 1 to 3 hours, when a fatigue test for repeatedly pulling the strip sample is performed under conditions of a set temperature of 25°C, a distance between chucks of 20 mm, test speed of 5 mm / min and stress of a repeated load of 100 MPa, the number of pulling until the strip sample is broken is 100 cycles or more.SELECTED DRAWING: None

Description

Technical Field

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

Background Art

[0002] In order to achieve high-speed transmission and miniaturization of semiconductor devices, semiconductor packages that combine materials with different physical properties in a complex manner to increase density have been proposed. In such semiconductor packages, since the stress on the semiconductor element and the redistribution layer increases, materials that relieve stress and have high mechanical reliability are required.

[0003] In order to reduce the stress on the Low-k material formed on the semiconductor element, a surface protective film capable of relieving stress is required, and an interlayer insulating film capable of withstanding higher stress than conventional ones is required for fan-out type packages. Further, in order to reduce the low heat resistance of the semiconductor element and the stress of the semiconductor package, the materials used for the surface protective film and the interlayer insulating film are required to be thermally cured at a temperature of 250°C or lower.

[0004] In response to such requirements, 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 phenol resin that can be cured at a low temperature 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

Patent Document 2

Patent Document 3

Patent Document 4

[0006] For photosensitive resin compositions for forming surface protective films or interlayer insulating films, materials having high reliability even when cured at a temperature of 250°C or lower are required to reduce stress, warpage, and damage to semiconductor elements. Furthermore, due to environmental load, safety, and device surface constraints, photosensitive materials that can be developed with an aqueous alkali solution are strongly demanded. However, it is difficult for these materials to satisfy sufficient mechanical reliability in a package form with high stress, and cracks may occur in the protective film or insulating film.

[0007] The present disclosure provides a simple screening method for a photosensitive resin composition that can be developed with an aqueous alkali solution, forms a cured film having high reliability mechanically and thermally shockingly without cracks or the like even when cured at 250°C or lower, a photosensitive resin composition selected by this screening method, a method for manufacturing a patterned cured film using the photosensitive resin composition selected by this screening method, and a method for manufacturing a semiconductor device. [Means for Solving the Problems]

[0008] One aspect of the present disclosure is to expose a resin film of a photosensitive resin composition at 100 to 2000 mJ / cm 2 and perform heat treatment at 150 to 250°C for 1 to 3 hours under nitrogen to produce a strip sample of a cured film with a film thickness of 10 μm and a width of 10 mm, and perform a fatigue test of repeatedly pulling the strip sample under the conditions that the set temperature is 25°C, the chuck distance is 20 mm, the test speed is 5 mm / min, and the stress of the repeated load is 100 MPa, and select a photosensitive resin composition in which the number of pulling cycles until the strip sample breaks in the fatigue test is 100 cycles or more, relating to a screening method of a photosensitive resin composition.

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

[0010] Another aspect of the present disclosure is that a resin film of a photosensitive resin composition is exposed at 100 to 2000 mJ / cm 2 and heat-treated at 150 to 250°C for 1 to 3 hours under nitrogen to produce a strip sample of a cured film with a film thickness of 10 μm and a width of 10 mm. When a fatigue test of repeatedly pulling the strip sample is performed under the condition that the set temperature is 25°C, the distance between chucks is 20 mm, the test speed is 5 mm / min, and the stress of the repeated load is 100 MPa, or under the condition that the set temperature is -55°C, the distance between chucks is 20 mm, the test speed is 5 mm / min, and the stress of the repeated load is 120 MPa, the present disclosure relates to a photosensitive resin composition in which the number of pulling cycles until the strip sample breaks is 100 cycles or more.

[0011] Another aspect of the present disclosure relates to a method for manufacturing a patterned cured film, including a step of applying and drying a photosensitive resin composition selected by the above-described method for selecting a photosensitive resin composition on a part or the whole surface of a substrate to form a resin film, a step of exposing at least a part of the resin film, a step of developing the exposed resin film to form a patterned resin film, and a step of 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 protection layer.

Advantages 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 aqueous alkali solution and forms a cured film having high reliability mechanically and thermally shockingly without cracks or the like even when cured at 250°C or lower.

[0014] The present disclosure provides a method for selecting a photosensitive resin composition that does not cause cracks due to thermal shock such as a temperature cycle test when used as a surface protective film or an interlayer insulating film, and selects materials by a fatigue test at 25°C or -55°C, which is an unprecedentedly low temperature. The fatigue fracture resistance at 25°C and -55°C is correlated with the thermal shock reliability (package reliability), and the evaluation of the thermal shock reliability (package reliability), which requires time for sample preparation and evaluation, can be easily evaluated in a short time by a fatigue test that is simple and can be evaluated immediately. When a pattern cured film is manufactured using the selected photosensitive resin composition, a semiconductor device excellent in thermal shock reliability that does not cause cracks or the like in a temperature cycle test can be manufactured.

Brief Description of the Drawings

[0015]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Embodiments for Carrying Out 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 "step" includes not only an independent step but also a step in which, even if it cannot be clearly distinguished from other steps, the intended action of the step is achieved. In this specification, the term "layer" includes, in addition to a structure formed over the entire surface when observed as a plan view, a structure formed partially.

[0017] In this specification, a numerical range indicated using "~" indicates a range including the numerical values described before and after "~" as the minimum value and the maximum value, respectively. In the numerical ranges described stepwise in this specification, the upper limit value or the lower limit value of a certain stepwise numerical range may be replaced with the upper limit value or the lower limit value of another stepwise numerical range. Further, in the numerical ranges described in this specification, the upper limit value or the lower limit value of the numerical range may be replaced with the value shown in the examples.

[0018] When referring to the amount of each component in a composition in this specification, when there are a plurality of substances corresponding to each component in the composition, unless otherwise specified, it means the total amount of the plurality of substances present in the composition. In this specification, "(meth)acrylic acid" means at least one of "acrylic acid" and the 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 this embodiment, a resin film of the photosensitive resin composition is exposed at 100 to 2000 mJ / cm 2 and heat-treated under nitrogen at 150 to 250°C for 1 to 3 hours to prepare a strip sample of a cured film with a film thickness of 10 μm and a width of 10 mm. Under the conditions where the set temperature is 25°C, the chuck distance is 20 mm, the test speed is 5 mm / min, and the stress of the repeated load is 100 MPa, a fatigue test is performed in which the strip sample is repeatedly pulled, and a photosensitive resin composition is selected in which the number of pulling cycles until the strip sample breaks in the fatigue test is 100 cycles or more.

[0020] In another aspect of the method for selecting a photosensitive resin composition according to the present embodiment, the resin film of the photosensitive resin composition is exposed at 100 to 2000 mJ / cm 2 and heat-treated at 150 to 250 °C for 1 to 3 hours under nitrogen to produce a strip sample of a cured film with a film thickness of 10 μm and a width of 10 mm. Under the conditions that the set temperature is -55 °C, the chuck distance is 20 mm, the test speed is 5 mm / min, and the stress of the repeated load is 120 MPa, a fatigue test is performed by repeatedly pulling the strip sample, and a photosensitive resin composition in which the number of pulling cycles until the strip sample breaks in the fatigue test is 100 cycles or more is selected.

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

[0022] In the method for selecting a photosensitive resin composition according to the present embodiment, a fatigue test of the strip sample is performed, and a photosensitive resin composition in which the number of pulling cycles until the strip sample breaks is 100 cycles or more is selected. The fatigue test can be performed under any of the following conditions (1) or (2). Condition (1): Under the conditions that the set temperature is 25°C, the distance between chucks is 20 mm, the test speed is 5 mm / min, and the stress of the repeated load is 100 MPa, the strip sample is repeatedly pulled (0 - 100 MPa). Condition (2): Under the conditions that the set temperature is -55°C, the distance between chucks is 20 mm, the test speed is 5 mm / min, and the stress of the repeated load is 120 MPa, the strip sample is repeatedly pulled (0 - 120 MPa).

[0023] By selecting a photosensitive resin composition in which the number of pulling cycles until the strip sample breaks in the fatigue test is 100 cycles or more, a cured film excellent in thermal shock reliability characteristics can be obtained, and the occurrence of cracks and the like can be reduced in the temperature cycle test of the semiconductor package. The number of pulling cycles at which breakage occurs in the strip sample in the fatigue test is defined as "fatigue fracture resistance". The number of pulling cycles when the strip sample breaks is preferably 250 cycles or more, more preferably 500 cycles or more, still more preferably 800 cycles or more, and particularly preferably 1000 cycles or more.

[0024] According to the photosensitive resin composition selected by the selection method of the photosensitive resin composition according to the present embodiment, even in a package with a large difference in the linear expansion coefficient between copper and resin, stress derived from organic materials such as a sealing material, and warpage, cracks in the resin layer can be suppressed, and in a package form with high stress, a semiconductor device excellent in reliability against thermal shock due to temperature cycling can be manufactured.

[0025] After conducting a fatigue test for 100 cycles, the elongation at break of the strip sample in a tensile test where the strip sample is pulled under the conditions of a set temperature of 25°C, a chuck distance of 20 mm, and a test speed of 5 mm / min is preferably 10 to 60%. When the elongation rate of the cured film is 10% or more, stress relaxation becomes easier, and stress tends to concentrate on the semiconductor element or other organic members, improving the reliability of the semiconductor package. When the elongation rate of the cured film is 60% or less, the cured film tends to be less likely to become fragile during temperature cycling. The elongation rate of the cured film is more preferably 15% or more in terms of being able to relax stress more, and even more preferably 20% or more in terms of improving crack resistance.

[0026] The elongation rate is obtained by measuring the elongation rate at break when pulling a sample after conducting a fatigue test of condition (1) or condition (2) for 100 cycles using an autograph (AG-1kNXplus) with a special thermostatic chamber manufactured by Shimadzu Corporation, with a set temperature of -55°C, a chuck distance of 20 mm, and a test speed of 5 mm / min until it breaks.

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

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

[0029] In the above tensile test, measurements are made under three different stress conditions where the number of repeated tensile cycles is 2 to 1000. Plot the horizontal axis as the number of repeated tensile cycles at break and the vertical axis as the measured stress conditions, and the stress value at 1000 cycles of the approximate straight line obtained from the three points can be determined as the limit stress of the cured film of the photosensitive resin composition. The limit 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 heat history.

[0030] The Young's modulus of the strip sample measured in the above 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 difficult to deform when stress is applied, and it is easy to suppress the concentration of stress on materials with a high Young's modulus mounted on the semiconductor package. When the Young's modulus of the cured film is 2.8 GPa or less, the stress is relaxed by the cured film and it is difficult to damage the semiconductor element. 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] The Young's modulus can be calculated from the slope in the elongation range of 0 to 5% of the curve obtained by plotting the horizontal axis as the elongation rate and the vertical axis as the stress in the above tensile test.

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

[0033] Tg can be obtained by using a dynamic viscoelasticity measuring device manufactured by UBM Corporation, measuring the viscoelasticity of the above strip sample in the temperature range of 40 to 260 °C with a chuck distance of 20 mm, a frequency of 10 Hz, and a heating rate of 5 °C / min, and taking the temperature showing the maximum value of tanδ as the glass transition temperature.

[0034] The linear expansion coefficient of the cured film of the photosensitive resin composition according to this embodiment is preferably 20 to 100 ppm / °C (20×10 -6 ~100×10 -6 / °C). When the linear expansion coefficient of the cured film is 100 ppm / °C or less, the stress during temperature change can be suppressed. When the linear expansion coefficient of the cured film is 20 ppm / °C or more, the generation of cracks is likely to be suppressed.

[0035] The adhesion rate of the cured film of the photosensitive resin composition according to this embodiment to the electrolytic copper plating substrate is preferably 75% or more. When the adhesion rate is 75% or more, when stress is applied, the cured film peels off from the electrolytic copper plating pattern that is the base, and stress tends to concentrate on a material with a high adhesion rate to the electrolytic copper plating mounted on the semiconductor package. The higher the adhesion rate, the better, more preferably 90% or more, still more preferably 95% or more, and particularly preferably 100%.

[0036] The adhesion rate can be measured by the following procedure. First, the photosensitive resin composition is applied to an electrolytic copper plating substrate using a spin coater so that the film thickness after curing is 10 μm, and heated under nitrogen at 200°C for 2 hours to form a cured film. Next, for the cured film, a temperature cycle test is repeated 200 times under an atmospheric air atmosphere with a temperature range of -65 to 150°C and a dwell time of 15 minutes, with -65°C as the start and end temperatures. After that, the cured film is cut into a grid pattern by the cross-cut method defined in JIS K 5600-5-6. A tape peeling test of the cured film cut into a grid pattern is performed to calculate the ratio (adhesion rate) of the grid (cured film) adhering to the electrolytic copper plating substrate.

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

[0038] ((A) Component: Alkali-soluble resin) From the viewpoint of improving the alkali developability, the photosensitive resin composition according to the present embodiment can contain an alkali-soluble resin as the (A) component. In the present specification, the alkali-soluble resin means a resin that is soluble in an aqueous alkali solution (developer). The aqueous alkali solution is an alkaline solution such as an aqueous solution of tetramethylammonium hydroxide (TMAH), an aqueous solution of a metal hydroxide, or an aqueous solution of an organic amine. Generally, an aqueous TMAH solution having a concentration of 2.38% by mass is used for development. The fact that the (A) component is soluble in the alkali developer can be confirmed, for example, as follows.

[0039] A varnish obtained by dissolving the resin in an arbitrary solvent is spin-coated on a substrate such as a silicon wafer to form a coating film having a thickness of about 5 μm. This is immersed in any of an aqueous TMAH solution, an aqueous metal hydroxide solution, or an aqueous organic amine solution at 20 to 25°C. As a result, when the coating film can be uniformly dissolved, the resin can be regarded as soluble in the alkali developer.

[0040] The (A) component is not particularly limited as long as it is soluble in a 2.38% by mass aqueous TMAH solution, but 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 resin, polybenzoxazole resin, polyamide resin, novolak resin which is a condensate of phenol-formaldehyde, cresol-formaldehyde condensed novolak resin, phenol-naphthol / formaldehyde condensed novolak resin, polyhydroxystyrene or its copolymer, phenol-xylylene glycol condensed resin, cresol-xylylene glycol condensed resin, phenol-dicyclopentadiene condensed resin, and an acrylic polymer 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]

Chemical formula

[0044] From the viewpoints of pattern formability and void reduction during thermocompression bonding, the phenolic hydroxyl group equivalent of the acrylic polymer having a phenolic hydroxyl group is preferably 200 to 700 g / eq.

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

[0046] Examples of monomers having other structural units include, for example, 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, dicyclopentenyl acrylate, dicyclopentenyl methacrylate, dicyclopentenyl itaconate, dicyclopentenyl maleate, dicyclopentenyl fumarate, dicyclopentenyl oxyethyl acrylate, dicyclopentenyl oxyethyl methacrylate, dicyclopentenyl oxyethyl itaconate, dicyclopentenyl oxyethyl maleate, dicyclopentenyl oxyethyl 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, ethylidene norbornene, 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. Although not particularly limited, an acrylic polymer having a carboxyl group in the side chain is preferably used as the compound having a carboxyl group.

[0048] (A) component may be used by mixing (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. By adopting such a configuration, a cured film having more excellent reliability can be obtained.

[0049] When mixing (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, it is preferable to blend (A2) in an amount of 5 to 30 parts by mass with respect to 100 parts by mass of (A1). When the blending 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. When 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 the (A) component is the peak temperature of tanδ when measured under the conditions of a temperature rising rate of 5 °C / min, a frequency of 1 Hz, and a measurement temperature of -150 to 300 °C using a viscoelastic analyzer (trade name "RSA-2", manufactured by Rheometrics) for the (A) component formed into a film.

[0051] The weight average molecular weight (Mw) of the (A) component is preferably controlled within the range of 2000 to 200000, more preferably 3000 to 100000, and still more preferably 5000 to 80000. In particular, the Mw of the alkali-soluble resin of (A1) is preferably 2000 to 50000, more preferably 4000 to 30000 from the viewpoint of reliability, and still more preferably 2000 to 30000 from the viewpoint of resolution during pattern formation. Also, the Mw of the alkali-soluble resin of (A2) is preferably 10000 to 100000, more preferably 15000 to 100000 from the viewpoint of reliability, and still more preferably 15000 to 70000 from the viewpoint of resolution during pattern formation.

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

[0053] (A) component may contain an alkali-soluble resin having an imide group from the viewpoint of further improving the fatigue fracture resistance. 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 in that the concentration of the imide group can be arbitrarily adjusted. 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 novolak resin or a phenol 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 the structural unit based on the (meth)acrylate compound having an imide group 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 sufficiently imparting fatigue fracture resistance, and preferably 60% by mass or less in terms of not impairing the alkali solubility, based on all monomer units constituting the alkali-soluble resin having an imide group.

[0055] The content of the alkali-soluble resin having an imide group 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 heat history, and further preferably 30% by mass or more in terms of sufficiently imparting fatigue fracture resistance, based on the total amount of the (A) component.

[0056] The (A) component may contain an alkali-soluble resin having an imide group and an alkali-soluble resin having no imide group. Thereby, it is possible to highly achieve both the fine processability during development of the photosensitive resin composition and the fatigue fracture resistance of the cured film.

[0057] The content of the alkali-soluble resin having an imide group 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, still more preferably 20% by mass or more in terms of maintaining sufficient fatigue fracture strength even after heat deterioration of the cured film, still 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 fine processability during development of the photosensitive resin composition. 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 the present embodiment preferably contains a (B) thermosetting resin. Examples of the (B) thermosetting resin include acrylate resin, epoxy resin, cyanate ester resin, maleimide resin, allyl nadimide resin, phenol resin, urea resin, melamine resin, alkyd resin, unsaturated polyester resin, diallyl phthalate resin, silicone resin, resorcinol formaldehyde resin, triallyl cyanurate resin, polyisocyanate resin, a resin containing tris(2-hydroxyethyl) isocyanurate, a resin containing triallyl trimellitate, and a thermosetting resin synthesized from cyclopentadiene. From the viewpoints of the resolution, insulation reliability, and adhesion to metal of the photosensitive resin composition, the thermosetting resin is more preferably a compound having any one selected from a methylol group, an alkoxyalkyl group, and a glycidyl group.

[0059] By incorporating a compound having a glycidyl group as component (B) into the photosensitive resin composition, when the resin film after pattern formation is heated and cured, it reacts with component (A) to form a crosslinked structure. Thereby, the brittleness and melting of the cured film can be prevented. As the compound having a glycidyl group, conventionally known ones can be used. Examples of the compound having a glycidyl group include bisphenol A epoxy resin, bisphenol F epoxy resin, phenol novolac epoxy resin, cresol novolac epoxy resin, alicyclic epoxy resin, glycidylamine, heterocyclic epoxy resin, and polyalkylene glycol diglycidyl ether.

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

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

[0062] Examples of the radical photoinitiator include alkylphenone-based photoinitiators, acylphosphine-based photoinitiators, intramolecular hydrogen abstraction-type photoinitiators, and cationic photoinitiators. These photoinitiators can be purchased as Omnirad 651, Omnirad 184, Omnirad 1173, Omnirad 2959, Omnirad 127, Omnirad 907, Omnirad 369, Omnirad 379EG, Omnirad 819, Omnirad MBF, Omnirad TPO, Omnirad 784 manufactured by IGM Resins; Irgacure OXE01, Irgacure OXE02, Irgacure OXE03, Irgacure OXE04, etc. manufactured by BASF. These radical photoinitiators may be used alone or in combination of two or more types according to the purpose, application, etc.

[0063] The photoacid generator has a function of generating an acid upon light irradiation and increasing the solubility of the irradiated portion in an alkaline aqueous solution. Examples of the photoacid generator include o-quinonediazide compounds, aryldiazonium salts, diaryliodonium salts, and triarylsulfonium salts. Among these, o-quinonediazide compounds are preferred because of their high sensitivity. As the o-quinonediazide compound, for example, a compound obtained by subjecting o-quinonediazide sulfonyl chloride and a hydroxy compound, an amino compound, etc. to a condensation reaction in the presence of a dehydrochlorinating agent can be used. The reaction temperature may be 0 to 40 °C, and the reaction time may be 1 to 10 hours.

[0064] Examples of the o-quinonediazide sulfonyl chloride 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 the hydroxy compound 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, 2,2',4,4'-tetrahydroxybenzophenone, 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-dimethylinden[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 perspective of reactivity when synthesizing o - quinonediazide compounds and from the perspective of having an appropriate absorption wavelength range when exposing the resin film, it is preferable to use a compound obtained by subjecting 1,1 - bis(4 - hydroxyphenyl)-1 - [4 - {1 - (4 - hydroxyphenyl)-1 - methylethyl}phenyl]ethane and 1 - naphthoquinone - 2 - diazide - 5 - sulfonyl chloride to a condensation reaction, a compound obtained by subjecting tris(4 - hydroxyphenyl)methane or tris(4 - hydroxyphenyl)ethane and 1 - naphthoquinone - 2 - diazide - 5 - sulfonyl chloride to a condensation reaction.

[0068] Examples of the dehydrochlorinating agent include sodium carbonate, sodium hydroxide, sodium hydrogen carbonate, 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 - quinonediazide sulfonyl chloride and the hydroxy compound and / or amino compound are preferably blended such that the total number of moles of the hydroxy group and the amino group is 0.5 to 1 mole with respect to 1 mole of the o - quinonediazide sulfonyl chloride. The preferable blending ratio of the dehydrochlorinating agent to the o - quinonediazide sulfonyl chloride is in the range of 0.95 / 1 to 1 / 0.95 molar equivalents.

[0070] From the viewpoints of the dissolution rate difference between the exposed part and the unexposed part and the allowable range of sensitivity, the content of component (C) is preferably 3 to 100 parts by mass, more preferably 5 to 50 parts by mass, and still more preferably 5 to 30 parts by mass with respect to 100 parts by mass of component (A).

[0071] (Component (D): Low - molecular - weight compound having a phenolic hydroxyl group) The photosensitive resin composition according to the embodiment can contain a low-molecular compound having a phenolic hydroxyl group. The low-molecular compound having a phenolic hydroxyl group is used to increase the dissolution rate of the exposed portion during development with an alkaline aqueous solution and improve the sensitivity. By containing the component (D), when the resin film after pattern formation is heated and cured, the component (D) reacts with the component (A) to form a crosslinked structure. Thereby, the brittleness and melting of the cured film can be prevented.

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

[0073] As the low-molecular compound having a phenolic hydroxyl group, conventionally known ones can be used, but the compound represented by the following general formula (2) is particularly preferable in terms of the balance between the effect of promoting the dissolution of the exposed portion and the effect of preventing the melting during the curing of the resin film.

[0074]

Chemical formula

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

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

[0077] [Chemical formula]

[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 thereof are substituted with halogen atoms, a sulfone group, a carbonyl group, an oxy group, a thio group, or an amide 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 a plurality of R'' may be the same as or different from each other.

[0079] The compounding amount of the low molecular weight compound having a phenolic hydroxyl group is preferably 1 to 50 parts by mass, more preferably 2 to 30 parts by mass, and still more preferably 3 to 25 parts by mass with respect to 100 parts by mass of the component (A) from the viewpoints of development time, allowable range of unexposed portion residual film ratio, and properties of the cured film.

[0080] (Other components) 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 by heating, an elastomer, a dissolution accelerator, a dissolution inhibitor, a coupling agent, a solvent, a surfactant, and a leveling agent.

[0081] (Compound that generates an acid by heating) The photosensitive resin composition according to the embodiment can 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 heating the pattern resin film, promoting the reaction of component (A), component (B), and component (D), that is, the thermal crosslinking reaction, and improving the heat resistance of the pattern cured film. In addition, 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. Therefore, the difference in solubility in the alkaline aqueous solution between the unexposed portion and the exposed portion becomes even greater, and the resolution is further improved.

[0082] The compound that generates an acid upon heating is preferably, for example, one that generates an acid when heated to 50 to 250°C. Examples of the compound that generates an acid upon heating include salts formed from strong acids such as onium salts and bases, and imide sulfonates.

[0083] Examples of onium salts include diaryl iodonium salts such as aryl diazonium salts and diphenyliodonium salts; di(alkylaryl) iodonium salts such as diaryl iodonium salts and di(t-butylphenyl) iodonium salts; trialkylsulfonium salts such as trimethylsulfonium salts; dialkylmonoaryl sulfonium salts such as dimethylphenylsulfonium salts; diarylmonoalkyl iodonium salts such as diphenylmethylsulfonium salts; and triarylsulfonium salts. Among these, the di(t-butylphenyl) iodonium salt of paratoluenesulfonic acid, the di(t-butylphenyl) iodonium salt of trifluoromethanesulfonic acid, the trimethylsulfonium salt of trifluoromethanesulfonic acid, the dimethylphenylsulfonium salt of trifluoromethanesulfonic acid, the diphenylmethylsulfonium salt of trifluoromethanesulfonic acid, the di(t-butylphenyl) iodonium salt of nonafluorobutanesulfonic acid, the diphenyliodonium salt of camphorsulfonic acid, the diphenyliodonium salt of ethanesulfonic acid, the dimethylphenylsulfonium salt of benzenesulfonic acid, and the diphenylmethylsulfonium salt of toluenesulfonic acid are preferred.

[0084] As salts formed from strong acids and bases, in addition to the above-mentioned onium salts, salts formed from the following strong acids and bases can also be used, for example, pyridinium salts. 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] Examples of imidosulfonates include naphthoylimidosulfonate and phthalimididosulfonate.

[0086] As compounds that generate acids upon heating, in addition to the above-mentioned ones, 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. R 5 R 6 C=N-O-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, a phenyl group, etc., an alkyl group such as a methyl group, an ethyl group, an isopropyl group, etc., or a perfluoroalkyl group such as a trifluoromethyl group, a nonafluorobutyl group.

[0088] In formula (5), R 8It is, 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 the general formula (5) include 2,2'-bis(4-hydroxyphenyl)hexafluoropropane, 2,2'-bis(4-hydroxyphenyl)propane, and di(4-hydroxyphenyl)ether.

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

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

[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 can be used alone or in combination of two or more.

[0092] When using an elastomer, the blending amount may be 1 to 50 parts by mass or 5 to 30 parts by mass with respect to 100 parts by mass of the component (A). When the blending amount of the elastomer is 1 part by mass or more, the thermal shock resistance of the cured film tends to improve. When it is 50 parts by mass or less, the resolution and the heat resistance of the obtained cured film are less likely to decrease, and the compatibility and dispersibility with other components are less likely to decrease.

[0093] (Dissolution promoter) By incorporating a dissolution accelerator into the photosensitive resin composition, the dissolution rate of the exposed area during development with an aqueous alkali solution can be increased, and the sensitivity and resolution can be improved. Conventionally known dissolution accelerators can be used. Examples of the dissolution accelerator include compounds having a carboxy group, a sulfonic acid, or a sulfonamide group. The blending amount when using the dissolution accelerator can be determined by the dissolution rate with respect to the aqueous alkali solution. For example, it can be 0.01 to 30 parts by mass with respect to 100 parts by mass of the component (A).

[0094] (Dissolution inhibitor) The dissolution inhibitor is a compound that inhibits the solubility of the component (A) in the aqueous alkali solution and is used to control the residual film thickness, development time, and contrast. Examples of the dissolution inhibitor include diphenyliodonium nitrate, bis(p-tert-butylphenyl)iodonium nitrate, diphenyliodonium bromide, diphenyliodonium chloride, and diphenyliodonium iodide. The blending amount when using the dissolution inhibitor may be 0.01 to 20 parts by mass, 0.01 to 15 parts by mass, or 0.05 to 10 parts by mass with respect to 100 parts by mass of the component (A) from the viewpoint of the allowable range of sensitivity and development time.

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

[0096] Examples of the organosilane 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, ethyln-propylphenylsilanol, ethylisopropylphenylsilanol, n-butylethylphenylsilanol, isobutylethylphenylsilanol, 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(propyl-dihydroxysilyl)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 using the coupling agent, the compounding amount may be 0.1 to 20 parts by mass or 0.5 to 10 parts by mass with respect to 100 parts by mass of the component (A).

[0098] (Surfactant or leveling agent) By blending a surfactant or a leveling agent into the photosensitive resin composition, the coatability can be further improved. Specifically, for example, by containing a surfactant or a leveling agent, striations (non-uniform film thickness) can be further prevented, and the developability can be further improved. Examples of the surfactant or the leveling agent include polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl ether, and polyoxyethylene octylphenol ether. Examples of commercially available products of the surfactant or the leveling agent include Megafac F171, F173, R-08 (trade name, manufactured by DIC Corporation), Fluorad FC430, FC431 (trade name, manufactured by Sumitomo 3M Limited), organosiloxane polymers KP341, KBM303, KBM403, and KBM803 (trade name, manufactured by Shin-Etsu Chemical Co., Ltd.).

[0099] When using a surfactant or a leveling agent, the blending amount may be 0.001 to 5 parts by mass or 0.01 to 3 parts by mass with respect to 100 parts by mass of the component (A).

[0100] (Solvent) The photosensitive resin composition contains a solvent to dissolve or disperse each component, thereby facilitating coating on a substrate and achieving the effect of forming a coating film with a 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 solvent can be used alone or in combination of two or more kinds.

[0102] The blending amount of the solvent is not particularly limited, but it is preferably adjusted so that the proportion of the solvent in the photosensitive resin composition is 20 to 90% by 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, and tetramethylammonium hydroxide (TMAH). By using the photosensitive resin composition according to this embodiment, it is possible to form a resist pattern with a good shape having sufficiently high sensitivity and resolution, good adhesion, and heat resistance.

[0104] [Method for manufacturing a pattern cured film] The method for manufacturing a pattern cured film (resist pattern) according to this embodiment includes a step of applying and drying the above-described photosensitive resin composition on a part or the whole surface of a substrate to form a resin film (coating · drying (film formation) step), a step of exposing at least a part of the resin film (exposure step), a step of developing the resin film after exposure to form a pattern resin film (development step), and a step of heating the patterned pattern resin film (photosensitive resin film) (heat treatment step). Hereinafter, each step will be described.

[0105] (Coating and Drying (Film Formation) Process) First, the photosensitive resin composition according to this embodiment is applied onto a substrate and dried to form a resin film. In this process, the photosensitive resin composition is spin-coated onto substrates such as glass substrates, semiconductors, metal oxide insulators (e.g., TiO2, SiO2, etc.), and silicon nitride using a spinner or the like to form a coating film. The substrate on which this coating film is formed is dried using a hot plate, an oven, or the like. There are no particular restrictions on the drying temperature and drying time, but it may be at 80 to 140 °C for 1 to 7 minutes. As a result, a photosensitive resin film is formed on the substrate.

[0106] (Exposure Process) Next, in the exposure process, actinic rays such as ultraviolet rays, visible light, and radiation are irradiated onto the resin film formed on the substrate through a mask. In the above-mentioned photosensitive resin composition, since the component (A) has high transparency to i-line, irradiation with i-line can be preferably used. Note that, after exposure, post-exposure baking (PEB) can be performed if necessary. The temperature of post-exposure baking is preferably 70 to 140 °C, and the time of post-exposure baking is preferably 1 to 5 minutes.

[0107] (Development Process) In the development process, the exposed portion of the resin film after the exposure process is removed with a developer, whereby the resin film is patterned to obtain a patterned resin film. As the developer, for example, an alkaline aqueous solution such as sodium hydroxide, potassium hydroxide, sodium silicate, ammonia, ethylamine, diethylamine, triethylamine, triethanolamine, and tetramethylammonium hydroxide (TMAH) is preferably used. The base concentration of these aqueous solutions may be 0.1 to 10% by mass. Alcohols or surfactants can also be added to the above developer for use. These may be blended in the range of 0.01 to 10 parts by mass or 0.1 to 5 parts by mass with respect to 100 parts by mass of the developer, respectively. When developing using a developer, for example, the developer is disposed on the resin film by methods such as shower development, spray development, immersion development, and paddle development, and left for 30 to 360 seconds under the conditions of 18 to 40 °C. After leaving, it is washed with water and spin-dried to wash the patterned resin film.

[0108] (Heat treatment step) Next, in the heat treatment step, a pattern cured film (resist pattern) can be formed by heat-treating the pattern resin film. The heating temperature in the heat treatment step is 250°C or lower, 225°C or lower, or may be 140 to 200°C from the viewpoint of sufficiently preventing damage to the electronic device due to heat.

[0109] The heat treatment can be performed using an oven such as a quartz tube furnace, a hot plate, rapid thermal annealing, a vertical diffusion furnace, an infrared curing furnace, an electron beam curing furnace, or a microwave curing furnace. Also, either the atmosphere or an inert atmosphere such as nitrogen can be selected, but nitrogen is desirable because it can prevent oxidation of the pattern. Since the above-mentioned heating temperature range is lower than the conventional heating temperature, damage to the substrate and the electronic device can be suppressed to a small level. Therefore, by using the method for manufacturing a pattern cured film according to the present embodiment, an electronic device can be manufactured with a high yield. Further, it leads to energy saving of the process. Furthermore, according to the photosensitive resin composition according to the present embodiment, since the volume shrinkage (curing shrinkage) in the heat treatment step seen in photosensitive polyimide or the like is small, a decrease in dimensional accuracy can be prevented.

[0110] The heat treatment time in the heat treatment step may be a time sufficient for the photosensitive resin composition to cure, but is preferably approximately 5 hours or less in consideration of work efficiency.

[0111] [[ID=I5]] The heat treatment can also be performed using a microwave curing device or a frequency-variable microwave curing device in addition to the above-mentioned oven. By using these devices, it is possible to effectively heat only the resin film while maintaining the temperature of the substrate and the electronic device at a desired temperature (for example, 200°C or lower).

[0112] In a variable-frequency microwave curing apparatus, since microwaves are irradiated in a pulsed manner while changing their frequency, standing waves can be prevented, and the substrate surface can be heated uniformly. Further, when the substrate includes metal wiring like the electronic components described later, irradiating microwaves in a pulsed manner while changing the frequency can prevent the occurrence of discharges from the metal and protect the electronic components from destruction. Furthermore, when heating is performed using variable-frequency microwaves, even if the curing temperature is lowered compared to the case of using an oven, the physical properties of the cured film are less likely to deteriorate (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 in practical use, it may be in the range of 1 to 10 GHz or 2 to 9 GHz. Also, it is desirable that the frequency of the irradiated microwave changes continuously, but in practice, the frequency is changed stepwise for irradiation. At that time, the time for irradiating the microwave of a single frequency should be as short as possible because standing waves, discharges from the metal, etc. are less likely to occur. Therefore, the irradiation time of the microwave is preferably 1 millisecond or less, and more preferably 100 microseconds or less.

[0114] The output of the irradiated microwave varies depending on the size of the apparatus or the amount of the object to be heated, but is generally in the range of 10 to 2000 W, and in practical use, it may be 100 to 1000 W, 100 to 700 W, or 100 to 500 W. When the output is 10 W or more, it becomes easier to heat the object to be heated in a short time, and when it is 2000 W or less, a rapid temperature rise is less likely to occur.

[0115] It is preferable to turn the microwave on and off in a pulsed manner for irradiation. Irradiating the microwave in a pulsed manner is preferable in that the set heating temperature can be maintained and damage to the cured film and the substrate can be avoided. The time for irradiating the pulsed microwave once varies depending on the conditions, but is generally preferably 10 seconds or less.

[0116] According to the method for manufacturing a pattern hardening film as described above, a pattern hardening film having sufficiently high sensitivity and resolution and good heat resistance can be obtained. The pattern hardening film according to the present embodiment can be used as an interlayer insulating layer or a surface protection layer of a semiconductor element.

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

[0118] First, a structure 100 shown in FIG. 1 is prepared. 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 where the circuit elements are exposed and covering 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 formed by spin coating or the like on the protective film 2 and the first conductor layer 3.

[0119] Next, a photosensitive resin layer 5 having a window portion 6A is formed on the interlayer insulating layer 4 to obtain a structure 200 shown in FIG. 2. The photosensitive resin layer 5 is formed, for example, by applying a photosensitive resin such as a chlorinated rubber type, a phenol novolak type, a polyhydroxystyrene type, or a polyacrylate type by spin coating. The window portion 6A is formed by a known photolithography technique 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 to obtain the structure 300 shown in FIG. 3. For the etching of the interlayer insulating layer 4, dry etching means using a gas such as oxygen or carbon tetrafluoride can be used. By this etching, the interlayer insulating layer 4 in the portion corresponding to the window portion 6A is selectively removed, and the interlayer insulating layer 4 provided with the window portion 6B is obtained such that the first conductor layer 3 is exposed. Next, the photosensitive resin layer 5 is removed using an etching solution that etches 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 to obtain the structure 400 shown in FIG. 4. For the formation of the second conductor layer 7, a known photolithography technique can be used. Thereby, an electrical connection between the second conductor layer 7 and the first conductor layer 3 is made.

[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 the present embodiment, the surface protection layer 8 is formed as follows. First, the photosensitive resin composition according to the above-described embodiment is applied onto the interlayer insulating layer 4 and the second conductor layer 7 by the spin coating method and dried to form a resin film. Next, after irradiating light through a mask having a pattern corresponding to the window portion 6C drawn in a predetermined portion, the resin film is developed with an aqueous alkali solution to pattern the resin film. Thereafter, the resin film is cured by heating to form a film 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, α-rays, etc., and the obtained semiconductor device 500 has excellent reliability.

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

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

[0125] Further, since the above-described photosensitive resin composition is also excellent in stress relaxation properties, adhesiveness, etc., it can also be used as various structural materials in packages having various structures developed in recent years. Cross-sectional structures of an example of such a semiconductor device are shown in FIGS. 6 and 7.

[0126] FIG. 6 is a schematic cross-sectional view showing a wiring structure as an 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 surface side of the silicon chip 23, an Al wiring layer 12 having a pattern including a pad portion 15 formed on the interlayer insulating layer 11, an insulating layer 13 (for example, a P-SiN layer) and a surface protection layer 14 sequentially laminated on the interlayer insulating layer 11 and the Al wiring layer 12 while forming an opening on the pad portion 15, an island-shaped core 18 disposed in the vicinity of the opening on the surface protection layer 14, and a rewiring layer 16 extending on the surface protection layer 14 so as to be in contact with the pad portion 15 within the opening of the insulating layer 13 and the surface protection layer 14 and in contact with the surface of the core 18 opposite to the surface protection layer 14. Further, the semiconductor device 600 includes a cover coat layer 19 formed to cover the surface protection layer 14, the core 18, and the rewiring layer 16, and having an opening formed in a portion of the rewiring layer 16 on the core 18, a conductive ball 17 connected to the rewiring layer 16 with a barrier metal 20 interposed therebetween in the opening of the cover coat layer 19, 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 formed 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 an embodiment of a semiconductor device. In the semiconductor device 700 of FIG. 7, an Al wiring layer (not shown) and a pad portion 15 of the Al wiring layer are formed on a silicon chip 23, an insulating layer 13 is formed on the upper part thereof, and a surface protection layer 14 of the element is further formed. A rewiring layer 16 is formed on the pad portion 15, and the rewiring layer 16 extends up to the upper part of a connection portion 24 with the conductive ball 17. Further, a cover coat layer 19 is formed on the surface protection layer 14. The rewiring layer 16 is connected to the conductive ball 17 via a barrier metal 20.

[0128] In the semiconductor devices of FIGS. 6 and 7, the above-described photosensitive resin composition can be used not only for the interlayer insulating layer 11 and the surface protection layer 14, but also as a material for forming the cover coat layer 19, the core 18, the color 21, the underfill 22, etc. The cured product using the above-described photosensitive resin composition is excellent in adhesion to metal layers such as the Al wiring layer 12 and the rewiring layer 16, and sealing materials, etc., and has a high stress relaxation effect. Therefore, a semiconductor device using this cured product for the cover coat layer 19, the core 18, the color 21 such as solder, the underfill 22 used for flip chip, etc. will be extremely reliable.

[0129] The photosensitive resin composition according to this embodiment is particularly preferably used for the surface protection layer 14 and / or the cover coat layer 19 of the semiconductor device having the rewiring layer 16 in FIGS. 6 and 7. The film thickness of the surface protection layer or the 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 carried out using low-temperature heating of 200°C or less in the above heat treatment step that conventionally required 300°C or more. Furthermore, since the photosensitive resin composition according to this embodiment has a small volume shrinkage (curing shrinkage) in the heat treatment step seen in photosensitive polyimide, etc., a decrease in dimensional accuracy can be prevented. The pattern cured film formed from the photosensitive resin composition according to this embodiment has a high glass transition temperature, and thus becomes a surface protection layer with excellent heat resistance. As a result, electronic components such as highly reliable semiconductor devices can be obtained with good yield and high productivity.

Examples

[0131] Hereinafter, the present invention will be described more specifically with reference to examples. However, 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] ((A) component: alkali-soluble resin) (A) As components, P-1 to P-9 were prepared. The Mw and Tg of P-1 to P-9 are summarized in Table 1.

[0134] (P-1) Cresol novolak resin (m-cresol / p-cresol (molar ratio) = 60 / 40, Mw = 12000, Tg = 165 °C, trade 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, trade name "EP4080G", manufactured by Asahi Organic Chemicals Co., Ltd.)

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

[0136] (P-4) Into a flask, 44.5 g of 4-hydroxyphenyl methacrylate, 39.0 g of 2-hydroxyethyl methacrylate, 45.0 g of N-acryloyloxyethyl hexahydrophthalimide, 300 g of DMAC, and 6.43 g of AIBN were added, and the reaction was carried out at 80 °C for 6 hours under a nitrogen atmosphere. After adding 200 g of methanol, it was slowly dropped into 1000 g of ion-exchanged water, and the precipitated polymer was filtered and dried to obtain P-4.

[0137] (P-5) Into a flask, 43.0 g of methacrylic acid, 39.0 g of 2-hydroxyethyl methacrylate, 20.0 g of N-acryloyloxyethyl hexahydrophthalimide, 300 g of DMAC, and 5.10 g of AIBN were added, and the reaction was carried out at 80 °C for 6 hours under a nitrogen atmosphere. After adding 200 g of methanol, it was slowly dropped into 1000 g of ion-exchanged water, and the precipitated resin was filtered and dried to obtain P-5.

[0138] (P-6) Into a 300 mL flask equipped with a stirrer, a thermometer, a nitrogen replacement device (nitrogen inlet tube), and a reflux condenser with a water receiver, 14.64 g (0.04 mol) of 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane (trade name "BIS-AP-AF", manufactured by Central Glass Co., Ltd.), which is an amine component, 19.48 g (0.045 mol) of polyoxypropylene diamine (trade name "D-400", manufactured by BASF), 2.485 g (0.01 mol) of 3,3'-(1,1,3,3-tetramethyldisiloxane-1,3-diyl)bispropylamine (trade name "BY16-871EG", manufactured by Toray Dow Corning Co., Ltd.), and 80 g of N-methyl-2-pyrrolidone (NMP), which is a solvent, were charged, and the mixture was stirred to dissolve the amine component in the solvent. While cooling the above flask 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 nitrogen gas and kept warm for 5 hours to obtain an NMP solution of P-6.

[0139] (P-7) Into a flask equipped with a stirrer, a thermometer, a nitrogen replacement device (nitrogen inlet tube), and a reflux condenser with a moisture receiver, 7.15 g (0.025 mol) of 5,5'-methylenebis(anthranilic acid) (trade name "MBAA", manufactured by Wakayama Seika Kogyo Co., Ltd., molecular weight 286), which is a diamine, 25.98 g (0.06 mol) of "D-400 (polyoxypropylene diamine)", and 2.48 g (0.01 mol) of "BY16-871EG (3,3'-(1,1,3,3-tetramethyldisiloxane-1,3-diyl)bispropylamine)" were charged, and 110 g of NMP, which is a solvent, was added and stirred to dissolve the diamine in the solvent. While cooling the above flask in an ice bath, 31 g (0.1 mol) of 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 nitrogen gas and kept warm for 5 hours to obtain an NMP solution of P-7.

[0140] (P-8) Into a flask, 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 were added, and the reaction was carried out at 80 °C for 6 hours under a nitrogen atmosphere. After adding 200 g of methanol, it was slowly dropped into 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-necked flask equipped with a stirrer, a nitrogen inlet tube, and a thermometer, and a polymerizable monomer separately weighed (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. At room temperature (25 °C), about 160 rpm (min -1While stirring at the stirring rotation speed of ), nitrogen gas was flowed at a flow rate of 400 mL / min for 30 minutes to remove dissolved oxygen. Then, the inflow of nitrogen gas was stopped, the flask was sealed, and the temperature was raised to 65 °C in about 25 minutes in a constant temperature water bath. The polymerization reaction was carried out while maintaining the same temperature for 10 hours to obtain an ethyl lactate solution of acrylic resin P-9. The polymerization rate at this time was 99%.

[0142]

Table 1

[0143] (Component (B): 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 (trade name “BEO-60E”, manufactured by Shin Nippon Rika Co., Ltd.)

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

[0145] (Component (D): Low molecular compound having 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) in the blending 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 were mixed. The mixture was pressure-filtered using a polytetrafluoroethylene resin filter with 3 μm pores to prepare a photosensitive resin composition.

[0147] [Table 2]

[0148] [Evaluation of the photosensitive resin composition] The following evaluations were performed on the photosensitive resin composition. The results are shown in Table 3.

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

[0150] (Fatigue fracture resistance) Using an autograph (AG-1kNXplus) with a special thermostatic chamber manufactured by Shimadzu Corporation, the fatigue tests of the above strip samples were each carried out under the following conditions. Condition (1): The strip sample was 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 stress of the repeated load of 100 MPa. Condition (2): The strip sample was 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 stress of the repeated load of 120 MPa.

[0151] The fatigue fracture resistance was evaluated as follows: under each condition, the measurement was performed three times, and when the average number of tensile cycles at which the strip sample broke exceeded 1000 cycles, it was designated as "A"; when it was between 100 and 1000 cycles, it was designated as "B"; and when the fracture occurred in less than 100 cycles, it was designated as "C".

[0152] (Elongation) In the examples, for the strip samples after performing the fatigue test under the above conditions for 100 cycles, using an autograph (AG-1kNXplus) with a special thermostat manufactured by Shimadzu Corporation, the strip samples were pulled under the conditions of a set temperature of 25°C, a distance between chucks of 20 mm, and a test speed of 5 mm / min, and the elongation rate at break was measured.

[0153] (Yield stress) In the above tensile test, the value of the stress at the intersection of the tangent line at the plot showing 5% elongation rate and the tangent line at the plot showing 15% elongation rate of the curve obtained by plotting the elongation rate on the horizontal axis and the stress on the vertical axis was defined as the yield stress.

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

[0155] For the strip samples prepared in the comparative examples, since the strip samples broke in less than 100 cycles of the fatigue test, the elongation, yield stress, and Young's modulus of the comparative examples were measured using strip samples without performing the fatigue test.

[0156] (Glass transition temperature) Using a dynamic viscoelasticity measuring device manufactured by UBM Corporation, the viscoelasticity of the strip sample was measured in the temperature range of 40 to 260°C at a distance between chucks of 20 mm, a frequency of 10 Hz, and a heating rate of 5°C / min, and the temperature showing the maximum value of tanδ was defined as the glass transition temperature (Tg).

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

[0158] For the sample for adhesion rate evaluation, a temperature cycle test was repeated 200 times under an atmospheric pressure air atmosphere, with the temperature ranging from -65 to 150 °C and a dwell time of 15 minutes, using -65 °C as the starting and ending temperatures. After that, it was cut in a grid pattern by the cross-cut method specified in JIS K 5600-5-6. Then, a tape with an adhesion strength of 10 ± 1 N per 25 mm width was attached to a 25-cell grid (cured film), and the tape was peeled off vertically within 5 minutes at a rate of 0.5 to 1.0 seconds. The number of grids that were peeled off at the edges of the cuts or at the intersections where the cured film was peeled off was measured, and the ratio (adhesion rate) of the grids (cured film) adhering to the electrolytically plated copper substrate was calculated. The adhesion rate was evaluated as "A" when it was 100%, "B" when it was 75% or more and less than 100%, and "C" when it was less than 75%.

[0159] (Reliability) A photosensitive resin composition was applied to an 8-inch silicon wafer with a thickness of 400 μm by a spin coater so that the film thickness after curing would be 10 μm, and then heated on a hot plate at 100 °C for 5 minutes. After that, it was heated under nitrogen at 200 °C for 2 hours to prepare the first cured film. A seed layer was formed by a sputtering apparatus such that 50 nm of Ti and 200 nm of Cu were formed thereon. A resist material was patterned, and electrolytic plating was performed so that the copper thickness would be 5 μm. The resist material was removed with NMP, and Cu and Ti were removed by etching to prepare a first copper pattern with a diameter of 350 μm. For the parts other than the copper pattern, a photomask designed so that the residual copper rate would be 70% was used with a copper mesh pattern.

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

[0161] A seed layer was formed by a sputtering apparatus such that 50 nm of Ti and 200 nm of Cu were formed thereon. Through a photomask designed to form a 240-μm-diameter opening at the center of the first-layer copper pattern with a diameter of 350 μm, a resist material was patterned and electrolytically plated so that the copper thickness would be 5 μm. The resist material was removed with NMP, and Cu and Ti were removed by etching to produce a second-layer copper pattern with a diameter of 240 μm. For the portions other than the copper pattern, a photomask designed such that the copper mesh pattern would have a residual copper rate of 30% was used. A flux was applied onto the second-layer copper pattern with a diameter of 240 μm, a 250-μm-diameter solder ball (Eco Solder Ball SM705 manufactured by Senju Metal Industry Co., Ltd.) was mounted, and reflow was performed under a nitrogen atmosphere under profile conditions conforming to JEDEC (Semiconductor Technology Association; J-STD-020D). After that, the flux was washed to obtain a package for reliability evaluation.

[0162] The temperature cycle test of the above package was carried out under the condition of repeating 1000 times the standard of JESD22-A104 conditionB, which is a cycle of 15 min at -55 °C and 15 min at 125 °C, and 300 locations on the side walls of the second-layer copper pattern with a diameter of 240 μm were observed. When the number of locations where cracks occurred was less than 5%, it was rated as "A"; when it was 5 - 20%, it was rated as "B"; and when it exceeded 20%, it was rated as "C", and the package reliability (thermal shock reliability) was evaluated.

[0163]

Table 3

[0164] As shown in Table 3, the fatigue tests under conditions (1) and (2) are correlated with package reliability. By evaluating the fatigue fracture resistance of the cured film, it can be confirmed that the evaluation of thermal shock reliability (package reliability), which requires time for sample preparation and evaluation, can be easily performed in a short time. If a photosensitive resin composition with a fatigue fracture resistance of 100 cycles or more selected by the fatigue test is used, a pattern cured film excellent in thermal shock reliability (package reliability) can be formed, and a semiconductor device using this film is also excellent in thermal shock reliability.

Explanation of Signs

[0165] 1…Semiconductor substrate, 2…Protective film, 3…First conductor layer, 4…Interlayer insulation layer, 5…Photosensitive resin layer, 6A, 6B, 6C…Window portions, 7…Second conductor layer, 8…Surface protective layer, 11…Interlayer insulation layer, 12…Al wiring layer, 13…Insulation layer, 14…Surface protective layer, 15…Pad portion, 16…Rewiring layer, 17…Conductive ball, 18…Core, 19…Cover coat layer, 20…Barrier metal, 21…Color, 22…Underfill, 23…Silicon chip, 24…Connection portion, 100, 200, 300, 400…Structures, 500…Semiconductor device, 600…Semiconductor device, 700…Semiconductor device.

Claims

【Claim 1】 The resin film of the photosensitive resin composition is exposed at 100 to 2000 mJ / cm ２ and heat-treated at 150 to 250 °C for 1 to 3 hours under nitrogen to prepare a strip sample of a cured film with a film thickness of 10 μm and a width of 10 mm. When a fatigue test of repeatedly pulling the strip sample is performed under the conditions that the set temperature is 25 °C, the distance between chucks is 20 mm, the test speed is 5 mm / min, and the stress of the repeated load is 100 MPa, the number of pulling cycles until the strip sample breaks is 100 cycles or more. A photosensitive resin composition.

Images