Epoxy resin composition, film, semiconductor device, and method for manufacturing a semiconductor device.

Abstract

To provide a resin composition and a film that provide a semiconductor sealing film having excellent adhesion, electrical connection, reliability and film flexibility.SOLUTION: An epoxy resin composition contains (A) epoxy resin, (B) phenolic resin, (C) polyvinyl acetal resin, and (D) curing accelerator. The (C) polyvinyl acetal resin has a glass transition temperature (Tg) of 75°C or higher.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to epoxy resin compositions and films used as semiconductor encapsulation films such as NCF (Non-Conductive Film) during semiconductor mounting, semiconductor devices containing the same, and methods for manufacturing semiconductor devices. [Background technology]

[0002] Conventionally, in semiconductor packaging, the flip-chip method is used, in which the side of the IC (Integrated Circuit) chip with electrodes (bumps) formed on it faces the side of the substrate with electrodes (electrode pads) formed on it, and electrically connects the bumps of the IC chip and the electrode pads of the substrate. In this flip-chip method, in order to protect the connection between the electrodes from the outside and to alleviate stress caused by the difference in the coefficient of thermal expansion between the IC chip and the substrate, a liquid thermosetting adhesive called an underfill agent is usually poured between the semiconductor chip and the substrate after the electrodes are connected and allowed to harden.

[0003] In recent years, IC chips have been miniaturized rapidly. Consequently, the pitch between adjacent electrodes and the gap between the semiconductor chip and the substrate tend to become increasingly narrow. Therefore, when underfill material is injected between the IC chip and the substrate using capillary action, problems such as void formation and the need for long injection times occur. For this reason, a so-called first-in method has been attempted, in which a liquid adhesive called NCP (Non-Conductive Paste) or a film adhesive called NCF (Non-Conductive Film) is applied or attached to the IC chip or substrate in advance, and then the resin is cured by thermal compression bonding (TCB) using a flip-chip bonder or the like to connect the bumps of the IC chip and the electrode pads of the substrate (see Patent Document 1). [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2013-219286 [Overview of the Initiative] [Problems that the invention aims to solve]

[0005] The characteristics required of NCF include a variety of other features, as follows: First, when the NCF film is interposed between the semiconductor wafer / chip and the substrate, it is required that the film conforms well to the irregularities caused by electrodes on the surface of the semiconductor wafer / chip and the substrate, and that no voids are formed. If voids are formed, the adhesive strength and bulk strength of the NCF will decrease. "Adhesive strength" is an indicator of the strength of the interfacial adhesion between the NCF and the semiconductor wafer / chip and / or substrate, while "bulk strength" is an indicator of the brittleness of the cured product. A decrease in adhesive strength and bulk strength reduces the reliability of the semiconductor package.

[0006] Furthermore, NCF (Non-Corrosion Fiber) is required to have high solder wettability and excellent electrical connectivity. Furthermore, the NCF is required to exhibit excellent reliability after curing. Specifically, "excellent reliability" means that the adhesive strength remains high even after exposure to high temperature and high humidity environments, and that connection failures after heat cycling of semiconductor packages on which the NCF is mounted are suppressed.

[0007] Furthermore, NCF (Non-Covered Film) needs to be transported in tape form within or between equipment such as laminators during the process of attaching it to semiconductor wafers, and resistance to bending is required to ensure handling. On the other hand, polymer materials such as phenoxy resin and acrylic polymer are often used as film-forming agents for NCF. However, it has been found that using phenoxy resin makes it difficult to impart flexibility to the film, resulting in insufficient resistance to bending. As a result, when NCF is transported in tape form within or between equipment such as laminators, fragments of NCF are generated, leading to contamination of the equipment and wafers. In addition, chips and burrs occur in the NCF during the dicing process performed after the wafer attachment process, which can lead to mounting defects. Moreover, it has been found that while acrylic polymer can impart flexibility, it results in a high coefficient of thermal expansion (CTE), low adhesive strength at high temperatures, and insufficient reliability.

[0008] The present invention aims to provide a resin composition and film that solve the above problems, and more specifically, a resin composition and film that can provide a semiconductor encapsulation film with excellent adhesion, electrical connectivity, reliability, and film flexibility. [Means for solving the problem]

[0009] The specific means for solving the aforementioned problems are as follows: The first embodiment of the present invention is the following resin composition. (1)(A) Epoxy resin and, (B) Phenolic resin and (C) Polyvinyl acetal resin and (D) A curing accelerator, (C) The glass transition temperature (Tg) of the polyvinyl acetal resin is 75°C or higher. Epoxy resin composition. (2)(C) The epoxy resin composition according to (1) above, wherein the glass transition temperature (Tg) of the polyvinyl acetal resin is 90°C or higher. (3)(C) The epoxy resin composition according to (1) or (2) above, wherein the glass transition temperature (Tg) of the polyvinyl acetal resin is 100°C or higher. (4) The epoxy resin composition according to any one of (1) to (3) above, wherein the amount of polyvinyl acetal resin blended is 0.1 to 10% by mass relative to the total mass of the epoxy resin composition. (5)(C)An epoxy resin composition according to any one of (1) to (4) above, wherein the ratio of acetacetal groups to the total acetal groups in the polyvinyl acetal resin is 10 to 100 mol%. (6)(C)An epoxy resin composition according to any one of (1) to (5) above, wherein the polyvinyl acetal resin has a reactive functional group. (7)(C) The epoxy resin composition according to (6) above, wherein the reactive functional group of the polyvinyl acetal resin is a carboxyl group. (8)(D) The epoxy resin composition according to any one of (1) to (7) above, wherein the curing accelerator is an imidazole compound.

[0010] A second embodiment of the present invention is (9) a film comprising the epoxy resin composition described in any of (1) to (8) above. A third embodiment of the present invention is (10) a semiconductor device comprising an epoxy resin composition according to any of (1) to (8) above or a film according to (9) above.

[0011] A fourth embodiment of the present invention is the following method for manufacturing a semiconductor device. (11) A step of attaching the film described in (9) above to a wafer having electrodes to obtain a laminate of the film and the wafer. The process of separating a laminate of film and wafer into individual chips. A step of aligning the individualized chips with a substrate having electrodes so that the electrodes of the chips and the electrodes of the substrate come into contact, and A step of pressing a positioned chip and a substrate by heating and pressurizing so that a metal bond is formed between the electrodes of the chip and the electrodes of the substrate. A method for manufacturing a semiconductor device, including the above step.

Advantages of the Invention

[0012] According to the first embodiment of the present invention, an epoxy resin composition capable of providing a film for semiconductor encapsulation applications with excellent adhesiveness, electrical connectivity, reliability, and film flexibility can be obtained. Also, according to the second embodiment of the present invention, a film for semiconductor encapsulation applications with excellent adhesiveness, electrical connectivity, reliability, and film flexibility can be obtained. Furthermore, according to the third embodiment of the present invention, a semiconductor device with excellent electrical connectivity and reliability can be obtained. According to the fourth embodiment of the present invention, a method for manufacturing a semiconductor device with excellent electrical connectivity and reliability can be obtained.

Modes for Carrying Out the Invention

[0013] [Resin Composition] The epoxy resin composition according to the first embodiment of the present invention comprises (A) an epoxy resin, (B) a phenolic resin, (C) a polyvinyl acetal resin, (D) a curing accelerator, and the glass transition temperature (Tg) of the (C) polyvinyl acetal resin is 75°C or higher. According to this embodiment, a resin composition capable of providing a film for semiconductor encapsulation applications with excellent adhesiveness, electrical connectivity, reliability, and film flexibility can be obtained.

[0014] (A) Epoxy resin (A)エポキシ樹脂 The epoxy resin composition of this embodiment includes (A) epoxy resin (hereinafter also referred to as "component (A)"). (A) epoxy resin is a thermosetting component and contributes to film formation. (A) epoxy resin is a general term for thermosetting resins that can be cured by crosslinking and networking epoxy groups present in the compound, and includes prepolymer compounds before crosslinking and networking. (A) epoxy resin is not particularly limited as long as it has two or more epoxy groups. From the viewpoint of curing speed and reliability, compounds having 2 to 6 epoxy groups are more preferred.

[0015] In this embodiment, (A) epoxy resin includes an epoxy resin that is solid at room temperature (hereinafter also referred to as "solid epoxy resin") or an epoxy resin that is liquid at room temperature (hereinafter also referred to as "liquid epoxy resin"). From the viewpoint of film flexibility, it is preferable to use a combination of solid epoxy resin and liquid epoxy resin.

[0016] Examples of solid epoxy resins include bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, naphthalene type epoxy resin, phenol novolac type epoxy resin, phenol aralkyl type epoxy resin, cresol novolac type epoxy resin, biphenyl type epoxy resin, biphenyl novolac type epoxy resin, biphenyl aralkyl type epoxy resin, triphenylmethane type epoxy resin, and dicyclopentadiene type epoxy resin. Among the above, triphenylmethane-type epoxy resin, biphenyl aralkyl-type epoxy resin, phenol aralkyl-type epoxy resin, and dicyclopentadiene-type epoxy resin are preferred from the viewpoint of heat resistance, adhesion, and reliability. The solid epoxy resin may be any one of the above types, or two or more types may be used in combination.

[0017] The solid epoxy resin preferably has a number-average molecular weight (Mn) of 200 to 6000, and more preferably 300 to 4000. The number-average molecular weight (Mn) is measured using gel permeation chromatography (GPC) and converted using a polystyrene standard.

[0018] Examples of liquid epoxy resins include bisphenol A type epoxy resins with an average molecular weight of approximately 400 or less; branched polyfunctional bisphenol A type epoxy resins such as p-glycidyloxyphenyldimethyltrisbisphenol A diglycidyl ether; bisphenol F type epoxy resins; phenol novolac type epoxy resins with an average molecular weight of approximately 570 or less; and alicyclic epoxy resins such as vinyl(3,4-cyclohexene) dioxide, 3,4-epoxycyclohexylcarboxylic acid (3,4-epoxycyclohexyl)methyl, bis(3,4-epoxy-6-methylcyclohexylmethyl) adipate, and 2-(3,4-epoxycyclohexyl)5,1-spiro(3,4-epoxycyclohexyl)-m-dioxane. Examples of epoxy resins include: biphenyl-type epoxy resins such as 3,3',5,5'-tetramethyl-4,4'-diglycidyloxybiphenyl; glycidyl ester-type epoxy resins such as diglycidyl hexahydrophthalate, diglycidyl 3-methylhexahydrophthalate, and diglycidyl hexahydroterephthalate; glycidylamine-type epoxy resins such as diglycidylaniline, diglycidyltoluidine, triglycidyl-p-aminophenol, tetraglycidyl-m-xylylenediamine, and tetraglycidylbis(aminomethyl)cyclohexane; and hydantoin-type epoxy resins such as 1,3-diglycidyl-5-methyl-5-ethylhydantoin; and naphthalene ring-containing epoxy resins. Also, epoxy resins with a silicone backbone, such as 1,3-bis(3-glycidoxypropyl)-1,1,3,3-tetramethyldisiloxane, are also included. Furthermore, diepoxide compounds such as (poly)ethylene glycol diglycidyl ether, (poly)propylene glycol diglycidyl ether, butanediol diglycidyl ether, neopentyl glycol diglycidyl ether, and cyclohexanedimethanol diglycidyl ether; and triepoxide compounds such as trimethylolpropane triglycidyl ether and glycerin triglycidyl ether are also examples. Among the liquid epoxy resins mentioned above, from the viewpoint of suppressing void formation, bisphenol-type epoxy resins, aminophenol-type epoxy resins, and silicone-modified epoxy resins are preferred, and bisphenol A-type epoxy resins and bisphenol F-type epoxy resins are even more preferred. Liquid epoxy resin may be any one of the above types, or two or more types may be used in combination.

[0019] The liquid epoxy resin preferably has a viscosity of 100,000 mPa·s or less at room temperature (25°C). In this specification, viscosity refers to the value measured at a measurement temperature of 25°C using an appropriate viscometer depending on the viscosity range.

[0020] The liquid epoxy resin content is preferably 0.5 to 70 parts by mass, and more preferably 1 to 67 parts by mass, per 100 parts by mass of the epoxy resin of component (A).

[0021] (B) Phenolic resin The epoxy resin composition of this embodiment includes (B) phenol resin (hereinafter also referred to as "component (B)"). (B) phenol resin is an epoxy resin curing agent that reacts with the epoxy groups of the epoxy resin and contributes to film formation and solder wettability. (B) phenol resin is a general term for thermosetting resins that can be crosslinked and networked by phenolic hydroxyl groups present in the compound, and includes prepolymer compounds before crosslinking and networking. Examples of (B) phenol resins include phenol novolac resins and their alkylated or allylated derivatives, cresol novolac resins, phenol aralkyl (including phenylene and biphenylene skeletons) resins, naphthol aralkyl resins, triphenolmethane resins, dicyclopentadiene type phenol resins, etc. Among these, cresol novolac resins and phenol aralkyl resins are preferred because they can provide high solder wettability. Any one of the above (B) phenolic resins may be used, or two or more may be used in combination.

[0022] In the epoxy resin composition, the ratio of the number of epoxy group equivalents of (A) epoxy resin to the number of hydroxyl group equivalents of (B) phenol resin ([number of hydroxyl group equivalents of (B) component] / [number of epoxy group equivalents of (A) component]) is preferably 0.6 to 1.5, and more preferably 0.7 to 1.3. In this specification, functional group equivalents such as epoxy equivalent and hydroxyl group equivalent represent the molecular weight of the compound per functional group, and functional group equivalent numbers such as epoxy group equivalent number and hydroxyl group equivalent number represent the number of functional groups (equivalents) per mass (amount charged) of compound. The epoxy equivalent of (A) epoxy resin is theoretically the number obtained by dividing the molecular weight of component (A) by the number of epoxy groups in one molecule. The hydroxyl group equivalent of component (B) is theoretically the number obtained by dividing the molecular weight of component (B) by the number of hydroxyl groups in one molecule. The epoxy group equivalent number of component (A) is the number of epoxy groups (equivalents) per mass (amount charged) of component (A), and is the quotient obtained by dividing the mass (g) of epoxy resin (A) by the epoxy equivalent of that epoxy resin (if multiple epoxy resins are included, it is the sum of such quotients for each epoxy resin). The hydroxyl group equivalent number of component (B) is the number of hydroxyl groups (equivalents) per mass (amount charged) of component (B), and is the quotient obtained by dividing the mass (g) of phenol resin (B) by the hydroxyl group equivalent of that phenol resin (if multiple phenol resins are included, it is the sum of such quotients for each phenol resin). By setting [(B) hydroxyl group equivalent number] / [(A) Epoxy group equivalent number] within the above range, solder wettability is further enhanced, and electrical connectivity and reliability are further improved.

[0023] (C) Polyvinyl acetal resin The epoxy resin composition of this embodiment contains (C) polyvinyl acetal resin (hereinafter also referred to as "component (C)"). In this embodiment, the glass transition temperature (Tg) of the (C) polyvinyl acetal resin is 75°C or higher. By incorporating a (C) polyvinyl acetal resin with a glass transition temperature (Tg) of 75°C or higher, flexibility can be imparted to the film, and excellent reliability can be obtained.

[0024] The inventors have discovered that film-forming properties can be imparted to epoxy resin compositions by incorporating polyvinyl acetal resin. The film-forming agent imparts film-forming ability and assists in film formation by preventing distortion and repulsion during film formation. Here, distortion refers to the shrinking of the film edges toward the center during the film formation process, and repulsion refers to the occurrence of crater-like irregularities on the film surface during the film formation process. Even more surprisingly, the inventors have found that by including (C) polyvinyl acetal resin with a glass transition temperature (Tg) of 75°C or higher as the film-forming agent, superior film flexibility and reliability are obtained compared to when polyvinyl acetal resin with a glass transition temperature (Tg) of less than 75°C is included as the film-forming agent. Normally, when the temperature of a polymer compound is lowered below its glass transition temperature, the partial mobility of the molecular chains is lost, flexibility is lost, and it becomes a glassy state. It might seem that a film-forming agent with a low glass transition temperature (Tg) and high flexibility would be suitable for increasing the flexibility of the film, but in this embodiment, the results were contrary to that assumption.

[0025] In this embodiment, the Tg of the polyvinyl acetal resin is 75°C or higher, more preferably 80°C or higher, and even more preferably 100°C or higher. If the Tg of the polyvinyl acetal resin is less than 75°C, sufficient moisture resistance reliability (adhesion) cannot be obtained. The upper limit of the Tg of the polyvinyl acetal resin is not particularly limited, but for example, it is 150°C or lower, and preferably 130°C or lower.

[0026] (C) The polyvinyl acetal resin is not particularly limited, but examples include a polyvinyl acetal resin having a constituent unit represented by the following formula (1-1), a constituent unit represented by the following formula (1-2), and a constituent unit represented by the following formula (1-3).

[0027] [ka]

[0028] [ka]

[0029] [ka]

[0030] In the above equation (1-1), R 1 represents a hydrogen atom or an alkyl group having 1 to 12 carbon atoms. Examples of alkyl groups having 1 to 12 carbon atoms include linear or branched alkyl groups such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, s-butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, and dodecyl groups. Among these, linear or branched alkyl groups having 1 to 3 carbon atoms, such as methyl, ethyl, propyl, and isopropyl groups, are preferred, and methyl or propyl groups are particularly preferred. (C) When the polyvinyl acetal resin has multiple structural units represented by the above formula (1-1), multiple R 1 They may be the same or different.

[0031] (C) The ratio of the constituent units represented by formula (1-1) to the total constituent units of the polyvinyl acetal resin is not particularly limited, but is, for example, 40 to 85 mol%, preferably 45 to 80 mol%, and more preferably 60 to 78 mol%.

[0032] (C) The ratio of the constituent units represented by formula (1-2) to the total constituent units of the polyvinyl acetal resin is not particularly limited, but is, for example, 0.1 to 20 mol%, preferably 0.1 to 15 mol%.

[0033] (C) The ratio of the constituent units represented by formula (1-3) to the total constituent units constituting the polyvinyl acetal resin is not particularly limited, but is, for example, 12 to 55 mol%, preferably 17 to 50 mol%, and more preferably 20 to 36 mol%.

[0034] (C) Polyvinyl acetal resin having the constituent units represented by the above formulas (1-1), (1-2), and (1-3) can also be represented as polyvinyl acetal having the constituent units represented by the following formula (1). [ka]

[0035] R in equation (1) above 1 This is R in equation (1-1) above. 1 It is synonymous with [the above]. q, r, and s are the proportions of each constituent unit to the total constituent units of the (C) polyvinyl acetal resin. q is not particularly limited, but is, for example, 40-85 mol%, preferably 45-80 mol%, and more preferably 60-78 mol%. r is not particularly limited, but is, for example, 0.1-20 mol%, preferably 0.1-15 mol%. s is not particularly limited, but is, for example, 12-55 mol%, preferably 17-50 mol%, and more preferably 20-36 mol%. The proportions of each constituent unit, represented by q, r, and s, can be measured, for example, by methods conforming to JIS K6728:1977 or JIS K6729:1977. They can also be measured by NMR.

[0036] In formulas (1) and (1-1), the constituent unit represented by formula (1-1) is also called an acetal group, R 1 When is a methyl group, the constituent unit represented by formula (1-1) is called an acetal group. In this embodiment, the ratio of acetal groups to the total acetal groups in (C) polyvinyl acetal resin is preferably 10 to 100 mol%, more preferably 30 to 100 mol%, and even more preferably 80 to 100 mol%. Having the ratio of acetal groups within this range further improves moisture resistance reliability (adhesion).

[0037] (C) The polyvinyl acetal resin may have constituent units represented by the following formulas (1-4). [ka] In the formula, R 2 (C) is a reactive functional group such as a carboxylic acid group, carboxyl group, amino group, or imino group. The reactive functional group is preferably a carboxyl group. The carboxylic acid group is not particularly limited, but examples include an acetate group, propionic acid group, butyric acid group, etc. (C) The presence of a reactive functional group in the polyvinyl acetal resin improves the compatibility of the (C) polyvinyl acetal resin with respect to the (A) epoxy resin, and the stress relaxation effect is increased, thus further improving the flexibility of the film. (C) When the polyvinyl acetal resin has a plurality of constituent units represented by the above formula (1-4), a plurality of R 2 They may be the same or different. (C) The ratio of the constituent units represented by formula (1-4) to the total constituent units constituting the polyvinyl acetal resin is not particularly limited, but is, for example, 0.01 to 10 mol%, and preferably 0.5 to 5 mol%.

[0038] (C) The number-average molecular weight (Mn) of the polyvinyl acetal resin is not particularly limited, but from the viewpoint of flexibility and film-forming properties, it is preferably 10,000 to 200,000, more preferably 15,000 to 150,000. The number-average molecular weight (Mn) is measured using gel permeation chromatography (GPC) and converted using a polystyrene standard.

[0039] In the epoxy resin composition of this embodiment, (C) polyvinyl acetal resin can be used alone or in combination of two or more types. (C) polyvinyl acetal resin can be manufactured by known methods (for example, the method described in Japanese Patent Application Publication No. 2012-102270). In addition, commercially available products can be used as (C) polyvinyl acetal resin.

[0040] The amount of (C) polyvinyl acetal resin in the resin composition is not particularly limited, but is preferably 0.1 to 10% by mass, more preferably 0.2 to 7% by mass, and even more preferably 0.3 to 5% by mass, relative to the total mass of the resin composition. By setting the amount of (C) polyvinyl acetal resin within this range, the viscosity of the resin composition becomes within an appropriate range, allowing for suitable filling of fine irregularities caused by bumps and wiring when NCF is attached to a wafer, and suppressing the occurrence of voids and unfilled areas. Furthermore, suitable reactivity is obtained.

[0041] (D) Curing accelerator The epoxy resin composition of this embodiment contains (D) a curing accelerator (hereinafter also referred to as "component (D)"). The curing accelerator of component (D) is not particularly limited as long as it is a curing accelerator for epoxy resin, but compounds containing nitrogen atoms are preferred because they can impart an appropriate curing rate. Examples of compounds containing nitrogen atoms include imidazole compounds, tertiary amines, diazabicycloundecene and diazabicycloundecene salts, imidazolines, aliphatic amines, aromatic amines, triazoles, tetrazoles, and hydrazides. Among these, component (D) is preferably an imidazole compound.

[0042] Examples of imidazole compounds include 2-methylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, and 2-phenyl-4,5-dihydroxymethylimidazole. Among these, 2-phenyl-4,5-dihydroxymethylimidazole is more preferred. In particular, by using 2-phenyl-4,5-dihydroxymethylimidazole, the resin composition is in a semi-cured state during soldering, resulting in a good connection. Furthermore, the curing rate of the resin composition is moderately slowed, and for example, when using a pressurized reflow oven, curing can be performed after void removal, thus leaving no voids in the cured product.

[0043] The amount of curing accelerator component (D) is preferably 0.01 to 5.0% by mass, more preferably 0.05 to 2.0% by mass, and even more preferably 0.1 to 1.0% by mass, relative to the total mass of (A) epoxy resin, (B) phenolic resin, (C) polyvinyl acetal resin, and (D) curing accelerator. By setting the amount of curing accelerator component (D) within this range, appropriate curability can be imparted, further improving productivity, electrical connectivity, and reliability.

[0044] (E) Silane coupling agent The epoxy resin composition of this embodiment may contain (E) a silane coupling agent (hereinafter also referred to as "component (E)") to the extent that it does not impair the effects of the present invention. The silane coupling agent has two or more different functional groups in its molecule, one of which is a silanol functional group that chemically bonds with inorganic materials, and the other is a functional group that chemically bonds with organic materials. The (E) silane coupling agent can improve the adhesion to wafers, chips, and substrates when the epoxy resin composition is used as NCF.

[0045] (E) Examples of silane coupling agents include, but are not limited to, various coupling agents such as epoxy, amino, vinyl, methacrylic, acrylic, and mercapto-based coupling agents, depending on the type of functional group that chemically bonds with the organic material. Among these, epoxy-based silane coupling agents and amino-based silane coupling agents are preferred from the viewpoint of adhesion, and amino-based silane coupling agents are more preferred.

[0046] Specific examples of epoxy silane coupling agents include 3-glycidoxypropyltrimethoxysilane (product name: KBM-403, manufactured by Shin-Etsu Chemical Co., Ltd.), 3-glycidoxypropyltriethoxysilane (product name: KBE-403, manufactured by Shin-Etsu Chemical Co., Ltd.), 3-glycidoxypropylmethyldiethoxysilane (product name: KBE-402, manufactured by Shin-Etsu Chemical Co., Ltd.), 3-glycidoxypropylmethyldimethoxysilane (product name: KBM-402, manufactured by Shin-Etsu Chemical Co., Ltd.), 8-glycidoxyoctyltrimethoxysilane (product name: KBM-4803, manufactured by Shin-Etsu Chemical Co., Ltd.), and 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane (product name: Sylace S530, manufactured by JNC Corporation). Specific examples of amino-based silane coupling agents include N-phenyl-3-aminopropyltrimethoxysilane (product name: KBM-573, manufactured by Shin-Etsu Chemical Co., Ltd.), N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane (product name: KBM-602, manufactured by Shin-Etsu Chemical Co., Ltd.), N-2-(aminoethyl)-3-aminopropyltrimethoxysilane (product name: KBM-603, manufactured by Shin-Etsu Chemical Co., Ltd.), 3-aminopropyltrimethoxysilane (product name: KBM-903, manufactured by Shin-Etsu Chemical Co., Ltd.), 3-aminopropyltriethoxysilane (product name: KBE-903, manufactured by Shin-Etsu Chemical Co., Ltd.), and 3-triethoxysilyl-N-(1,3-dimethylbutylidene)propylamine (product name: KBE-9103P, manufactured by Shin-Etsu Chemical Co., Ltd.). (E) One silane coupling agent may be used, or two or more may be used in combination.

[0047] When an epoxy resin composition contains an (E) silane coupling agent, the amount of the (E) silane coupling agent is preferably 0.01 to 3.5% by mass, and more preferably 0.05 to 3.0% by mass, relative to the total mass of the epoxy resin composition.

[0048] (F) Inorganic filler The epoxy resin composition of this embodiment may contain (F) inorganic filler (hereinafter also referred to as "(F) component") to the extent that it does not impair the effects of the present invention. By incorporating (F) inorganic filler into the epoxy resin composition, the coefficient of thermal expansion of the epoxy resin composition can be lowered, and when used as NCF, connection failures after heat cycling of the mounted semiconductor package can be suppressed. Inorganic fillers consist of granular bodies formed from inorganic materials and are not particularly limited as long as they have the effect of lowering the coefficient of thermal expansion when added. Examples of inorganic materials include silica, alumina, aluminum nitride, calcium carbonate, aluminum silicate, magnesium silicate, magnesium carbonate, barium sulfate, barium carbonate, lime sulfate, aluminum hydroxide, calcium silicate, potassium titanate, titanium oxide, zinc oxide, silicon carbide, silicon nitride, and boron nitride. One or more inorganic fillers may be used. Silica fillers are preferred because they allow for a higher filling capacity. Amorphous silica is preferred.

[0049] Inorganic fillers are preferably surface-treated with a coupling agent such as a silane coupling agent. This allows the thixotropic index (TI) of the resin composition to be within an appropriate range, thereby further improving the film-forming ability.

[0050] The shape of the inorganic filler is not particularly limited and may be spherical, flaky, needle-shaped, amorphous, or any other shape.

[0051] The average particle size of the inorganic filler is preferably less than 1.0 μm, more preferably 0.7 μm or less, and even more preferably 0.5 μm or less. By setting the average particle size of the inorganic filler within this range, the transmittance of the film can be increased, and the visibility of alignment marks during mounting can be improved.

[0052] In this specification, the average particle size is the particle size at 50% of the cumulative value in the volume-based particle size distribution, measured by laser diffraction-scattering. The maximum particle size is the largest particle size in the volume-based particle size distribution, measured by laser diffraction-scattering.

[0053] (F) The amount of inorganic filler added is preferably 30 to 80% by mass, more preferably 35 to 75% by mass, and even more preferably 40 to 70% by mass, relative to the total mass of the resin composition. (F) By setting the amount of inorganic filler above the lower limit, the coefficient of linear expansion is reduced, the heat cycle resistance is increased, and the thermal conductivity is also improved. (F) By setting the amount of inorganic filler below the upper limit, the viscosity of the resin composition is within an appropriate range, making it suitable for filling fine irregularities caused by bumps and wiring when attaching NCF to a wafer, and suppressing the occurrence of voids and unfilled areas. In addition, the decrease in connectivity due to filler entrapment during mounting is suppressed.

[0054] (G) Other additives The epoxy resin composition may further contain, as necessary, ion trapping agents, leveling agents, antioxidants, defoaming agents, flame retardants, colorants, reactive diluents, plasticizers, and / or other additives, to the extent that it does not impair the purpose of this embodiment. For example, the addition of a plasticizer can further enhance the flexibility of the film. The type and amount of each additive are as per conventional methods.

[0055] (H) Solvent The epoxy resin composition may contain a solvent used in varnish production. Examples of solvents include ketones such as methyl ethyl ketone and methyl isobutyl ketone; aromatic solvents such as toluene and xylene; high-boiling point solvents such as dioctyl phthalate and dibutyl phthalate; and glycol ethers such as propylene glycol monomethyl ether acetate. This solvent volatilizes during the film production of the epoxy resin composition and does not remain in the final film at levels that would cause voids in the semiconductor package.

[0056] (I) Fluxant The epoxy resin composition of this embodiment preferably contains substantially no fluxing agent. Generally, resin compositions that can be used as NCF (Non-Corrosion Fiber) use organic acids such as carboxylic acids or rosin derivatives as fluxing agents to improve solder wettability. However, many organic acids have low molecular weight components, which can cause variations in properties due to volatilization during the drying process and void generation due to volatilization during reflow soldering. In addition, the reactivity of organic acids can cause a reduction in lifespan. On the other hand, while rosin derivatives have low volatility, their solubility in solvents is low, making them difficult to apply to films. The epoxy resin composition of this embodiment can have excellent solder wettability even without containing a fluxing agent.

[0057] [Manufacturing of resin compositions] The epoxy resin composition of this embodiment can be obtained by stirring, melting, mixing, and dispersing, simultaneously or separately, components (A) to (D), and components (E), (F), and (G) and other additives, etc., in or without a solvent (H), while applying heat treatment as necessary. The apparatus for these mixing, stirring, and dispersion operations is not particularly limited, but a mixing machine equipped with stirring and heating devices, a three-roll mill, a ball mill, a planetary mixer, a bead mill, etc., can be used. These apparatuses may also be used in appropriate combinations.

[0058] The epoxy resin composition of this embodiment can be used, for example, to form films for semiconductor encapsulation applications.

[0059] [film] A film according to a second embodiment of the present invention comprises the epoxy resin composition of the first embodiment described above. This film can be used as a film for semiconductor encapsulation applications, exhibiting excellent adhesion, electrical connectivity, reliability, and film flexibility. The film for semiconductor encapsulation applications contains NCF.

[0060] The film can be provided as a film attached to a support or as a film peeled off from a support, after the epoxy resin composition prepared in the above procedure has been diluted with a solvent to form a varnish, applied to at least one side of a support, and dried.

[0061] Suitable solvents for use as varnish include ketones such as methyl ethyl ketone and methyl isobutyl ketone; aromatic solvents such as toluene and xylene; high-boiling point solvents such as dioctyl phthalate and dibutyl phthalate; and glycol ethers such as propylene glycol monomethyl ether acetate. The amount of solvent used is not particularly limited and can be the amount conventionally used, but preferably it is 20 to 90% by mass relative to the total mass of the varnish. This solvent volatilizes during the film preparation of the epoxy resin composition and does not remain in the final film at a level that would cause voids in the semiconductor package.

[0062] The support is appropriately selected according to the desired form in the method for manufacturing the resin composition and is not particularly limited, but examples include metal foil such as copper or aluminum, and resin carrier films such as polyester, polyethylene, and polyethylene terephthalate (PET). When the film of this embodiment is provided in the form of a film peeled from the support, it is preferable that the support is released with a release agent such as a silicone compound.

[0063] The method of applying the varnish is not particularly limited, but examples include the slot die method, gravure method, doctor coater method, etc., and can be appropriately selected depending on the desired film thickness. The application is carried out so that the thickness of the film formed after drying is the desired thickness. Such a thickness can be derived from the solvent content by those skilled in the art.

[0064] The drying conditions are designed appropriately according to the type and amount of solvent used in the varnish, the amount of varnish used, and the thickness of the application, and are not particularly limited, but for example, they can be set at 60-150°C and carried out under atmospheric pressure.

[0065] The film thickness is not particularly limited, but is preferably 1 μm or more, and more preferably 5 μm or more. Furthermore, the thickness is preferably 100 μm or less, and more preferably 50 μm or less.

[0066] If necessary, a separator film may be provided on top of the film. The composition of the separator film is arbitrary and includes, for example, polyester films such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate, and plastic films such as polyolefin films such as polypropylene and polyethylene. It is preferable that the release surface (the surface in contact with the epoxy resin composition film) of these films is treated with a release agent. Examples of release agents used in the release agent treatment include silicone-based, fluorine-based, and long-chain alkyl-based release agents. There are no particular restrictions on the thickness of the separator film, but it is usually between 20 μm and 250 μm. A backgrind tape or dicing tape may be provided instead of a separator film.

[0067] The film of this embodiment has excellent visibility. Therefore, when used as an NCF (Non-Cross Fiber), the recognition marks that serve as markers for wafers and chips can be confirmed through the NCF attached to the wafer.

[0068] The film of this embodiment has excellent bending resistance. Therefore, it offers excellent handling when transporting within or between devices such as laminators, and when mounting it to devices. Furthermore, when used as NCF, there is no risk of chipping or burrs occurring during the dicing process performed after lamination.

[0069] The film of this embodiment exhibits good adhesion to wafers, chips, and substrates when used as an NCF (Non-Covered Film). The film of this embodiment exhibits good moisture resistance reliability (adhesion) when used as NCF. The film of this embodiment can be applied to reflow soldering, thus offering high productivity. The film of this embodiment also possesses a flux effect and exhibits excellent solderability.

[0070] [Semiconductor device] A semiconductor device according to a third embodiment of the present invention includes the epoxy resin composition of the first embodiment or the film of the second embodiment described above.

[0071] The semiconductor device of this embodiment is not particularly limited as long as the epoxy resin composition of the first embodiment or the film of the second embodiment is used during the manufacture of the semiconductor device. A specific example of a semiconductor device is a semiconductor device having a flip-chip structure. The flip-chip has protruding electrodes called bumps, which are connected to electrodes such as a substrate. Examples of bump materials include solder, gold, and copper, and examples include structures in which each is used alone or in which a solder layer is formed on copper. Substrates connected to the flip-chip include single-layer or stacked organic substrates such as FR-4, and inorganic substrates such as silicon, glass, and ceramic. Electrodes are used that have copper, gold plating or tin plating on copper, OSP (Organic Solderability Preservative) treatment on copper, or a solder layer formed on copper. Examples of semiconductor devices with a flip-chip structure include memory devices such as DRAM (Dynamic Random Access Memory), processor devices such as CPU (Central Processing Unit) and GPU (Graphics Processing Unit), light-emitting elements such as LED (Light Emitting Diode), and driver ICs used in LCDs (Liquid Crystal Displays).

[0072] [Manufacturing method for semiconductor devices] A fourth embodiment of the present invention is a semiconductor manufacturing method, A step of attaching the film of the second embodiment described above to a wafer having electrodes to obtain a laminate of film and wafer, The process of separating a laminate of film and wafer into individual chips. A step of aligning the individualized chips with a substrate having electrodes so that the electrodes of the chips and the electrodes of the substrate come into contact, and A process of pressing the aligned chip and substrate together by heating and pressurizing so that a metallic bond is formed between the electrodes of the chip and the electrodes of the substrate. Includes.

[0073] First, a film according to the second embodiment is attached to one side of a wafer having electrodes to obtain a laminate of film and wafer. Specifically, if a separator film is provided on the film, the separator film is peeled off and the epoxy resin composition film is attached to one side of the wafer having electrodes. Here, the film can follow the irregularities caused by the electrodes on the wafer well and suppress the generation of voids at the interface between the film and the wafer.

[0074] Furthermore, wafers with electrodes may have low strength. Therefore, the wafer may be reinforced by fixing it to a support such as support glass via a temporary fixing material. In this case, after bonding the wafer-side surface of the laminate of the support and wafer to the film, the support is peeled off together with the temporary fixing material.

[0075] It is preferable to further laminate a dicing tape onto the film and wafer laminate before the next dicing step. In this case, the dicing tape may be attached to the wafer first, and the film may be attached to the side of the wafer opposite to the dicing tape. Alternatively, the film may be attached to the wafer first, and the dicing tape may be attached to the side of the wafer opposite to the film.

[0076] Next, the laminate of film and wafer is separated into individual chips (dicing process). At this time, the film is cut along with the wafer. The method of cutting the wafer is not particularly limited and can be carried out by various conventionally known dicing methods. For example, a method of cutting semiconductor wafers using a dicing blade can be used. Alternatively, other dicing methods such as laser dicing may be employed.

[0077] After the dicing process, the chips are picked up. At this time, the chips are picked up with the individualized film attached. In other words, the chips with the film attached are peeled off from the adhesive layer of the dicing tape. If the adhesive layer is made of an energy-ray curable adhesive, it is preferable to irradiate the adhesive layer with energy rays before picking up. This reduces the adhesive strength of the adhesive, making it easier to pick up the chips. If necessary, the spacing between the chips may be increased by expanding the dicing tape before picking up.

[0078] Next, the individualized chips are aligned onto a substrate with electrodes so that the electrodes on the chips and the electrodes on the substrate are in contact. After proper alignment, the chips are placed on the substrate.

[0079] Furthermore, the aligned chip and substrate are pressed together by heating and pressurizing to form a metallic bond between the electrodes of the chip and the electrodes of the substrate. This bonds the chip and substrate via a film, and electrically connects the electrodes of the chip and the electrodes of the substrate (soldering). The heating and pressurizing conditions depend on the metal composition used, but for example, they can be a temperature of 50-300°C, a pressure of 5-450N, and a time of 0.5-60 seconds. Heating and pressing include, but are not limited to, thermal compression bonding (TCB). While TCB conditions are not particularly limited, they can be appropriately selected depending on the semiconductor chip size, bump material, number of bumps, etc.

[0080] After soldering is complete, the film interposed between the chip and the substrate is cured. Curing can be performed, for example, by heating at 100-200°C for 1-120 minutes. Alternatively, this curing process may be carried out under pressure. Furthermore, this curing process may be omitted if the film has been cured by the heating and pressurizing process described above. [Examples]

[0081] The present invention will be described in more detail below with reference to examples and comparative examples, but the present invention is not limited to these examples. In the following examples, parts and % refer to parts by mass and mass%, respectively, unless otherwise specified.

[0082] (Example 1~ 3、6 , 11 and 12, Reference Example 1 ~6 (Comparative Examples 1-4) Each solid material was dissolved in methyl ethyl ketone. The materials were mixed and dispersed according to the proportions shown in the table below, and if necessary, diluted with methyl ethyl ketone to a viscosity suitable for coating, thereby preparing a coating varnish for the resin composition. A release agent was applied to a PET (polyethylene terephthalate) film (38 μm thick), and then a coating varnish was applied to a dry thickness of approximately 10 μm. The varnished and release agent-treated PET film was then dried in a dryer at 100°C for 10 minutes to remove the solvent, resulting in a 10 μm thick film. Note that the values ​​for each composition in the table represent parts by mass.

[0083] The components used in the preparation of the resin composition are as follows: (A) Epoxy resin (A1) Bisphenol F type epoxy resin (Product name: YDF-8170, epoxy equivalent weight 158 ​​g / eq, manufactured by Nippon Steel Chemical & Material Co., Ltd.) (A2) Triphenylmethane type epoxy resin (Product name: EPPN-501HY, epoxy equivalent 163-175 g / eq, manufactured by Nippon Kayaku Co., Ltd.) (A3) Dicyclopentadiene type epoxy resin (Product name: HP-7200L, epoxy equivalent weight 242-252 g / eq, manufactured by DIC Corporation) (B) Phenolic resin (B1) cresol Novolac-type phenolic resin (Product name: CRG-951, hydroxyl group equivalent 119 g / eq, manufactured by Aica Kogyo Co., Ltd.) (B2) Biphenyl aralkyl type phenolic resin (Product name: MEHC-7851 SS, hydroxyl group equivalent 201-205 g / eq, manufactured by Meiwa Kasei Co., Ltd.) (B3) Aralkyl-type phenolic resin (Product name: MEHC-7800 4S, hydroxyl group equivalent 176-180 g / eq, manufactured by Meiwa Kasei Co., Ltd.) (C) Polyvinyl acetal resin (C1) Product name: KS-23Z (Tg: 110℃, acetacetal ratio 98%, manufactured by Sekisui Material Solutions Co., Ltd.) (C2) Product name: KS-10 (Tg: 105℃, acetacetal ratio 89%, manufactured by Sekisui Material Solutions Co., Ltd.) (C3) Product name: BX-5Z (Tg: 92℃, acetacetal ratio 57%, manufactured by Sekisui Material Solutions Co., Ltd.) (C4) Product name: BX-L (Tg: 80℃, acetacetal ratio 36%, manufactured by Sekisui Material Solutions Co., Ltd.) (C'5) Product name: BL-1 (Tg: 70℃, acetacetal ratio 5%, manufactured by Sekisui Material Solutions Co., Ltd.) (C'6) Product name: BL-S (Tg: 66℃, acetacetal ratio 2%, manufactured by Sekisui Material Solutions Co., Ltd.) (C'') Phenoxy resin (C''1)BisA type phenoxy resin (product name: YP-50, Tg: 84℃, manufactured by Nippon Steel Chemical & Material Co., Ltd.) (D) Curing accelerator (D1) 2-phenyl-4,5-dihydroxymethylimidazole (product name: 2PHZ-PW, manufactured by Shikoku Chemicals Co., Ltd.) (E) Silane coupling material (E1) N-phenyl-3-aminopropyltrimethoxysilane (product name: KBM-573, manufactured by Shin-Etsu Chemical Co., Ltd.) (E2)3-Glycidoxypropyltrimethoxysilane (Product name: KBM-403, manufactured by Shin-Etsu Chemical Co., Ltd.) (F) Inorganic filler (F1) Phenylsilane-treated filler (Product name: Sciqas 0.1μm, average particle size 0.1μm, manufactured by Sakai Chemical Industry Co., Ltd.) (G) Plasticizer (G1) Bis(2-ethylhexanoic acid) triethylene glycol (product name: G-260, manufactured by Sumitomo Chemical Co., Ltd.)

[0084] The acetal ratio of the polyvinyl acetal resin of component (C) and component (C') was measured by NMR under the following conditions. Measurement method: 1 H-NMR Equipment: JNM-ECX400 Equipment manufacturer: JEOL Ltd. Solvent: Deuterated chloroform Evaluation method: The total acetal group and butyral group content was determined from the area ratio of the hydrogen atom signal of the -CH3 at the butyral group terminus (around 0.9 ppm) and the hydrogen atom signal of the O-CH-O in the total acetal (butyral + acetal) (around 4.5 ppm, 4.7 ppm, and 4.9 ppm), and the acetal ratio was calculated from there.

[0085] The following evaluations were performed using the films prepared according to the procedure described above.

[0086] (Film flexibility (bending resistance)) The film prepared using the above procedure was cut into 10mm x 100mm pieces to create test specimens. These specimens were folded 180 degrees by hand, and the presence or absence of cracks in the film and peeling from the PET coated with the release agent was visually checked. If no cracks occurred and there was no peeling from the PET, the result was "3"; if there were cracks but no peeling from the PET, the result was "2"; and if there were cracks and peeling from the PET occurred, the result was "1". The results are shown in Table 1.

[0087] (Adhesive strength) The film fabricated by the above procedure was attached to SiN with a 1 mm corner using a vacuum pressure laminator (manufactured by Naiki Seisakusho Co., Ltd., model number: MLP500 / 600). The SiN with a 1 mm corner was placed on the SiN of 20 mm × 40 mm such that the NCF was adhered to the SiN, and temporarily fixed on an 80°C hot plate and then post-cured at 150°C for 1 hour. Using a universal bond tester (Dage 4000 by Nordson Advanced Technology), the adhesive strength (unit: N / mm 2 ) was measured in shear mode. It was carried out with N = 14, and the average value of the adhesive strength was obtained. The results are shown in Table 1.

[0088] (Moisture resistance reliability (adhesive strength)) The test piece fabricated by the above adhesive strength evaluation method was left under the conditions of 85°C and 85% RH for 24 hours, and similarly, the adhesive strength (unit: N / mm 2 ) was measured and taken as the adhesive strength after the moisture resistance test. In the present invention, the adhesive strength after the moisture resistance test is preferably 45 N / mm 2 or more, more preferably 50 N / mm 2 or more. The results are shown in Table 1.

[0089]

Table 1

[0090] Examples 1 to 3、6 , 11, and 12 had good film flexibility (folding resistance), adhesiveness, and moisture resistance reliability. Examples 2 and 3 are examples in which (A) the combination of epoxy resins was changed compared to Example 1. Reference Examples 1 and 2 is an example in which (B) the combination of phenolic resins was changed compared to Example 1 Reference example . Examples 6 and Reference example 3 are examples in which (C) the blending amount of the components was changed compared to Example 1 and reference examples . Reference examples 4~6 is an example in which (C) the type of the components was changed compared to Example 1 See youThese are examples. Example 11 is an example in which (F) inorganic filler is not included compared to Example 1. Example 12 is an example in which the type of (E) silane coupling agent is changed compared to Example 1. Comparative Examples 1 and 2 were examples in which component (C) with a Tg of less than 75°C was incorporated, and both showed low adhesive strength after the humidity resistance test, resulting in low reliability. Comparative Example 3 was an example in which phenoxy resin was incorporated instead of component (C), resulting in low film flexibility (bending resistance). Comparative Example 4 was an example in which component (C) was not incorporated, resulting in low film flexibility (bending resistance), as well as low adhesive strength after the humidity resistance test, resulting in low reliability.

Claims

1. (A) Epoxy resin and (B) Phenolic resin and (C) Polyvinyl acetal resin and (D) A semiconductor encapsulation film formed from an epoxy resin composition containing a curing accelerator, (C) The glass transition temperature (Tg) of the polyvinyl acetal resin is 110°C or higher. (B) The phenol resin comprises a cresol novolac resin and a phenol aralkyl resin, (C) The amount of polyvinyl acetal resin blended is 0.3 to 10% by mass relative to the total mass of the epoxy resin composition. Film for semiconductor encapsulation.

2. (C) The semiconductor encapsulation film according to claim 1, wherein the ratio of acetacetal groups to the total acetal groups in the polyvinyl acetal resin is 10 to 100 mol%.

3. (C) The semiconductor encapsulation film according to claim 1 or 2, wherein the polyvinyl acetal resin has a reactive functional group selected from the group consisting of carboxylic acid groups, carboxyl groups, amino groups, and imino groups.

4. (C) The semiconductor encapsulation film according to claim 3, wherein the reactive functional group of the polyvinyl acetal resin is a carboxyl group.

5. (D) The semiconductor encapsulation film according to any one of claims 1 to 4, wherein the curing accelerator is an imidazole compound.

6. (D) The semiconductor encapsulation film according to any one of claims 1 to 5, wherein the curing accelerator is 2-phenyl-4,5-dihydroxymethylimidazole.

7. (E) A semiconductor encapsulation film according to any one of claims 1 to 6, comprising a silane coupling agent.

8. (F) A semiconductor encapsulation film according to any one of claims 1 to 7, comprising an inorganic filler.

9. A semiconductor encapsulation film according to any one of claims 1 to 8, comprising a plasticizer.

10. A semiconductor encapsulation film according to any one of claims 1 to 9, wherein no solvent remains.

11. A semiconductor encapsulation film according to any one of claims 1 to 10, which is interposed between a chip and a substrate in an application where a metallic bond is formed between the electrodes of a chip and the electrodes of a substrate.

12. A semiconductor device comprising a semiconductor encapsulation film according to any one of claims 1 to 11.

13. A step of attaching a semiconductor encapsulation film according to any one of claims 1 to 11 to a wafer having electrodes to obtain a laminate of the film and the wafer. The process of separating a laminate of film and wafer into individual chips. A step of aligning the individualized chips with a substrate having electrodes so that the electrodes of the chips and the electrodes of the substrate come into contact, and A process of pressing the aligned chip and substrate together by heating and pressurizing so that a metallic bond is formed between the electrodes of the chip and the electrodes of the substrate. A method for manufacturing a semiconductor device, including the method described above.

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