Adhesive for semiconductors, semiconductor device and manufacturing method thereof

Abstract

An adhesive agent for semiconductors according to the present invention, which comprises a thermoplastic resin, a heat-curable resin, a curing agent, and a flux compound having at least one carboxyl group, in which the flux compound has a structure such that a carbon atom located at α-position in the carboxyl group is substituted by at least one electron-withdrawing group.

Description

[Technical Field]

[0001] The present disclosure relates to an adhesive for semiconductors, as well as a semiconductor device and a method for manufacturing the same. [Background technology]

[0002] Conventionally, a wire bonding method using thin metal wires such as gold wires has been widely used to connect a semiconductor chip to a substrate.

[0003] In recent years, in order to meet the demands for higher functionality, higher integration, and higher speed for semiconductor devices, the flip-chip connection method (FC connection method) is becoming more widespread. This method involves forming conductive protrusions called bumps on a semiconductor chip or substrate to directly connect the semiconductor chip to the substrate.

[0004] For example, the COB (Chip On Board) type connection method, which is widely used for connecting semiconductor chips and substrates in BGA (Ball Grid Array), CSP (Chip Size Package), etc., also falls under the FC connection method. The FC connection method is also widely used in COC (Chip On Chip) type connection methods, in which connecting parts (bumps or wiring) are formed on semiconductor chips to connect semiconductor chips, and COW (Chip On Wafer) type connection methods, in which connecting parts (bumps or wiring) are formed on semiconductor wafers to connect semiconductor chips and semiconductor wafers (see, for example, Patent Document 1).

[0005] Furthermore, in the case of packages where there is a strong demand for further miniaturization, thinning, and high functionality, chip-stacked packages, POP (Package On Package), TSV (Through-Silicon Via), and other technologies that stack and multi-layer the above-mentioned connection methods are beginning to become widespread. These stacking and multi-layering technologies arrange semiconductor chips and other components in three dimensions, making it possible to make packages smaller than methods that arrange them in two dimensions. Furthermore, stacking and multi-layering technologies are effective in improving semiconductor performance, reducing noise, reducing mounting area, and saving power, and are therefore attracting attention as a next-generation semiconductor wiring technology.

[0006] Generally, metal bonding is used to connect connecting parts to each other in order to ensure sufficient connection reliability (e.g., insulation reliability). The main metals used for the above connecting parts (e.g., bumps and wiring) include solder, tin, gold, silver, copper, nickel, etc., and conductive materials containing a combination of these metals are also used. The metals used for connecting parts may oxidize on their surfaces to form oxide films, or impurities such as oxides may adhere to the surfaces, resulting in impurities on the connecting surfaces of the connecting parts. If such impurities remain, there is a concern that the connection reliability (e.g., insulation reliability) between a semiconductor chip and a substrate or between two semiconductor chips may decrease, thereby undermining the benefits of adopting the above-mentioned connection method.

[0007] One method for suppressing the generation of these impurities is to coat the connection parts with an anti-oxidation film, known as OSP (Organic Solderbility Preservatives) treatment, but this anti-oxidation film can sometimes cause a decrease in solder wettability and connectivity during the connection process.

[0008] Therefore, as a method for removing the oxide film and impurities, a method has been proposed in which a fluxing agent is contained in an adhesive for semiconductors (see, for example, Patent Document 2). [Prior art documents] [Patent documents]

[0009] [Patent Document 1] Japanese Patent Application Laid-Open No. 2008-294382 [Patent Document 2] International Publication No. 2013 / 125086 Summary of the Invention [Problem to be solved by the invention]

[0010] In recent years, in order to improve productivity, a process has been proposed in which multiple semiconductor chips are mounted and temporarily fixed on a mounting substrate (semiconductor chip, semiconductor wafer, wiring circuit board, etc.) using a semiconductor adhesive, and then cured and sealed all at once. In this process, heat (approximately 60 to 155°C) is applied to the stage to the extent that the semiconductor adhesive becomes flowable, temporarily fixing the semiconductor chips to the mounting substrate, and then the semiconductor adhesive is reflowed at a temperature above the melting point of the connecting parts (bumps or wiring) (for example, approximately 260°C) to cure the semiconductor adhesive all at once. This process allows multiple packages to be produced efficiently.

[0011] In the above process, voids may remain in the semiconductor adhesive, and in order to prevent the occurrence of these voids, a method of performing bulk curing under pressure conditions has been proposed. However, when the number of semiconductor chips increases, voids may remain even with the above method, and it has become clear that there is room for further improvement.

[0012] Therefore, one of the objects of the present disclosure is to reduce voids that may remain in a semiconductor adhesive during a process in which multiple semiconductor chips are temporarily fixed to a mounting member via a semiconductor adhesive and then cured and sealed all at once.

[0013] On the other hand, metal bonding is generally used to connect parts together in order to ensure sufficient connectivity and insulation reliability.If the semiconductor adhesive does not have sufficient flux activity (effectiveness in removing oxide films and impurities from the metal surface), the oxide films and impurities on the metal surface cannot be removed, a good metal-metal bond cannot be formed, and conductivity may not be ensured.

[0014] The present disclosure aims to provide a semiconductor adhesive that can reduce the above-mentioned voids and enable the fabrication of a semiconductor device with excellent connectivity. The present disclosure also aims to provide a semiconductor device and a method for manufacturing a semiconductor device using the semiconductor adhesive. [Means for solving the problem]

[0015] In order to achieve the above object, the present disclosure provides a semiconductor adhesive comprising a thermoplastic resin, a thermosetting resin, a curing agent, and a flux compound having at least one carboxyl group, wherein the flux compound has a structure in which at least one electron-withdrawing group is substituted on the alpha carbon of the carboxyl group.

[0016] The inventors have inferred that in a process in which multiple semiconductor chips are temporarily fixed to a mounting substrate using a semiconductor adhesive and then cured and sealed all at once, when a large number of semiconductor chips are mounted, the semiconductor adhesive partially cures during the temporary fixation process, resulting in voids more likely to remain in the semiconductor adhesive. In other words, because the semiconductor chips are mounted sequentially in the above process, the initially mounted semiconductor chips and the semiconductor adhesive continue to be subjected to thermal history from the stage until the final semiconductor chip is mounted. Therefore, it is inferred that as the number of semiconductor chips increases, the semiconductor adhesive temporarily fixing the initially mounted semiconductor chips partially cures, resulting in voids remaining and not being removed by the pressure applied during the batch curing process. Based on this inference, the inventors conducted further studies and completed the present disclosure.

[0017] It is believed that the semiconductor adhesive of the present disclosure has an electron-withdrawing group at the α-position carbon adjacent to the carboxyl group, which facilitates the removal of the carboxyl group's proton, thereby enabling the adhesive to exhibit high flux activity. In other words, the semiconductor adhesive of the present disclosure can remove an oxide film on the solder surface or an anti-oxidation film known as an OSP (organic solderability preservative) treatment, improving solder wettability during the connection process. This prevents cracks and peeling at the connection portion, enabling the fabrication of semiconductor devices with excellent connectivity. Furthermore, the semiconductor adhesive of the present disclosure can reduce voids that may remain in the semiconductor adhesive during the process of temporarily fixing multiple semiconductor chips to a mounting member via the semiconductor adhesive and then curing and sealing them all at once.

[0018] The flux compound may contain a compound having two carboxyl groups. A compound having two carboxyl groups is less likely to volatilize even at high temperatures during connection than a compound having one carboxyl group, and can further suppress the occurrence of voids. Furthermore, the use of a compound having two carboxyl groups can further suppress the increase in viscosity of the semiconductor adhesive during storage, connection work, etc., compared to a compound having three or more carboxyl groups, thereby further improving the connection reliability of semiconductor devices.

[0019] The flux compound may contain a compound represented by the following general formula (2-1) or (2-2): The compound represented by the following general formula (2-1) or (2-2) can further improve the reflow resistance and connection reliability of the semiconductor device. [ka] [ka] [In formulas (2-1) and (2-2), R 1 represents an electron-withdrawing group, and R 2 represents a hydrogen atom or an electron-withdrawing group, and R3 represents a hydrogen atom or a monovalent organic group, and n represents an integer of 0 to 15. 3 may be the same or different.]

[0020] The flux compound may contain a compound represented by the following general formula (3-1) or (3-2): The compound represented by the following general formula (3-1) or (3-2) can further improve the reflow resistance and connection reliability of the semiconductor device. [ka] [ka] [In formulas (3-1) and (3-2), R 1 represents an electron-withdrawing group, and R 2 represents a hydrogen atom or an electron-withdrawing group, and R 3 represents a hydrogen atom or a monovalent organic group, and m represents an integer of 0 to 10.]

[0021] The melting point of the flux compound may be 170° C. or lower. Such a compound exhibits sufficient flux activity before the curing reaction between the thermosetting resin and the curing agent occurs, and therefore, a semiconductor adhesive containing this compound can realize a semiconductor device with even more excellent connection reliability.

[0022] The thermosetting resin may contain an epoxy resin. By using an adhesive for semiconductors containing an epoxy resin, a semiconductor device with even more excellent connection reliability can be realized.

[0023] The curing agent may include an amine-based curing agent, which exhibits excellent curing properties through a curing reaction between the thermosetting resin and the curing agent, thereby further improving the reflow resistance of the semiconductor device.

[0024] The amine-based curing agent may include an imidazole-based curing agent. Use of such a compound can further improve the stability of the adhesive for semiconductors.

[0025] The structure of the imidazole-based curing agent may include a triazine ring. Use of such a compound can further improve the stability of the adhesive for semiconductors.

[0026] The present disclosure also provides a method for manufacturing a semiconductor device in which the respective connection portions of a semiconductor chip and a wiring circuit board are electrically connected to each other, or a semiconductor device in which the respective connection portions of multiple semiconductor chips are electrically connected to each other, comprising a sealing step of curing the semiconductor adhesive of the present disclosure by applying heat under a pressurized atmosphere, and sealing at least a portion of the connection portion with the cured semiconductor adhesive.

[0027] The manufacturing method may further include, before the sealing step, a step of arranging a plurality of semiconductor chips on a stage, and a temporary fixing step of sequentially arranging other semiconductor chips on each of the plurality of semiconductor chips arranged on the stage via the semiconductor adhesive while heating the stage to 60 to 155°C, thereby obtaining a plurality of stacks in which the semiconductor chips, the semiconductor adhesive, and the other semiconductor chips are stacked in this order.

[0028] Alternatively, the manufacturing method may further include a step of placing a wiring circuit board or a semiconductor wafer on a stage before the sealing step, and a temporary fixing step of sequentially placing multiple semiconductor chips on the wiring circuit board or semiconductor wafer placed on the stage via the semiconductor adhesive while heating the stage to 60 to 155°C, thereby obtaining a laminate in which the wiring circuit board, the semiconductor adhesive, and multiple semiconductor chips are stacked in this order, or a laminate in which the semiconductor wafer, the semiconductor adhesive, and multiple semiconductor chips are stacked in this order.

[0029] The present disclosure further provides a semiconductor device in which the connection portions of a semiconductor chip and a wiring circuit board are electrically connected to each other, or a semiconductor device in which the connection portions of multiple semiconductor chips are electrically connected to each other, wherein at least a portion of the connection portions is sealed with a cured product of the semiconductor adhesive of the present disclosure that has been cured by applying heat under a pressurized atmosphere. [Effects of the Invention]

[0030] According to the present disclosure, it is possible to reduce voids that may remain in the semiconductor adhesive during a process in which multiple semiconductor chips are temporarily fixed to a mounting member via a semiconductor adhesive and then cured and sealed all at once. According to the present disclosure, it is possible to provide a semiconductor adhesive that can reduce such voids and enables the fabrication of a semiconductor device with excellent connectivity, as well as a semiconductor device using the semiconductor adhesive and a method for manufacturing the same. [Brief explanation of the drawings]

[0031] [Figure 1] 1 is a schematic cross-sectional view showing an embodiment of a semiconductor device; [Figure 2] 1 is a schematic cross-sectional view showing an embodiment of a semiconductor device; [Figure 3] 1 is a schematic cross-sectional view showing an embodiment of a semiconductor device; [Figure 4] FIG. 1 is a circuit diagram of a semiconductor chip used in evaluating connectivity. DETAILED DESCRIPTION OF THE INVENTION

[0032] An embodiment of the present disclosure will be described in detail below, with reference to the drawings where appropriate. In the drawings, identical or corresponding parts are designated by the same reference numerals, and duplicate explanations will be omitted. Furthermore, unless otherwise specified, positional relationships such as up, down, left, and right are based on the positional relationships shown in the drawings. Furthermore, the dimensional ratios of the drawings are not limited to those shown.

[0033] The upper and lower limits of the ranges of values ​​described herein can be combined in any combination. The values ​​described in the examples can also be used as the upper or lower limits of the ranges of values. In this specification, "(meth)acrylic" means acrylic or its corresponding methacrylic.

[0034] <Semiconductor adhesive and its manufacturing method> The semiconductor adhesive of this embodiment contains a thermoplastic resin (hereinafter sometimes referred to as "component (a)"), a thermosetting resin (hereinafter sometimes referred to as "component (b)"), a curing agent (hereinafter sometimes referred to as "component (c)"), and a flux compound having at least one carboxyl group (hereinafter sometimes referred to as "component (d)"). The semiconductor adhesive of this embodiment may also contain a filler (hereinafter sometimes referred to as "component (e)"), if necessary.

[0035] The heat generation value of the DSC curve obtained by differential scanning calorimetry (DSC) of the semiconductor adhesive of this embodiment between 60 and 155°C may be 20 J / g or less. Here, the differential scanning calorimetry is performed by heating the semiconductor adhesive in an air or nitrogen atmosphere using a sample semiconductor adhesive weighing 10 mg, a measurement temperature range of 30 to 300°C, and a temperature rise rate of 10°C / min. The heat generation value is calculated by integrating the peak area.

[0036] Conventional semiconductor adhesives have an exothermic peak in the temperature range of 60 to 155°C on their DSC curves. It is believed that the heat generated in this temperature range is due to the reaction between the thermosetting resin and the flux compound in the semiconductor adhesive. As this reaction progresses, the semiconductor adhesive is presumably partially cured and its fluidity is reduced. Meanwhile, temporary fixing of semiconductor chips with a semiconductor adhesive is typically achieved by heating the semiconductor adhesive to, for example, 60 to 155°C to allow it to flow appropriately. Therefore, if a conventional semiconductor adhesive is used in a process in which multiple semiconductor chips are mounted and temporarily fixed on a mounting substrate (semiconductor chip, semiconductor wafer, wiring circuit board, etc.) via the semiconductor adhesive, and then cured and sealed all at once under pressure, it is presumed that the reaction between the thermosetting resin and the flux compound in the semiconductor adhesive during temporary fixing of the semiconductor chips causes partial curing of the semiconductor adhesive, resulting in insufficient fluidity during bulk curing under pressure. On the other hand, in the semiconductor adhesive of this embodiment, if the heat generation rate in the DSC curve between 60 and 155°C is 20 J / g or less, curing does not proceed easily in the temperature range (e.g., 60 to 155°C) where the semiconductor chip is temporarily fixed. Therefore, by using a semiconductor adhesive that satisfies the above-mentioned heat generation rate condition in the above process, multiple semiconductor chips can be temporarily fixed while maintaining sufficient fluidity of the semiconductor adhesive, and the occurrence of voids during simultaneous curing can be reduced. Furthermore, as a result of the reduced occurrence of voids, it is expected that defects (such as peeling of the semiconductor adhesive or poor electrical connection at the connection) will be less likely to occur even if the adhesive is heated to a temperature above the melting point of the connection portion (e.g., 260°C) in the reflow process. In other words, a semiconductor adhesive that satisfies the above-mentioned heat generation rate condition tends to improve reflow reliability (reflow resistance) in the manufacture of semiconductor devices.

[0037] The calorific value in the range from 60 to 155°C in the DSC curve is preferably 15 J / g or less, more preferably 10 J / g or less, and even more preferably 5 J / g or less, from the viewpoint of easily achieving the effects of the present invention. The calorific value in the range from 60 to 155°C in the DSC curve may be 20% or less, 15% or less, or 10% or less of the calorific value in the range from 60 to 280°C, from the viewpoint of easily achieving the effects of the present invention. The calorific value in the range from 60 to 280°C in the DSC curve may be 50 J / g or more or 100 J / g or more, and may be 200 J / g or less or 180 J / g or less, and may be 50 to 200 J / g, 100 to 200 J / g, or 100 to 180 J / g, from the viewpoint of easily achieving the effects of the present invention. Preferably, the DSC curve does not have an exothermic peak with an onset temperature of 155°C or less.

[0038] The semiconductor adhesive of this embodiment, which exhibits the above DSC curve, can be obtained, for example, by blending a curing agent and a flux compound so that the ratio of the number of moles of acid groups in the total flux compound to the number of moles of reactive groups (groups that react with acid groups in the flux compound) in the total curing agent is 0.01 to 4.8. That is, the method for producing a semiconductor adhesive of this embodiment may include a step of mixing a thermoplastic resin, a thermosetting resin, a curing agent, and a flux compound having at least one carboxyl group, and in this step, the curing agent and the flux compound may be blended so that the ratio of the number of moles of acid groups in the total flux compound to the number of moles of reactive groups in the total curing agent is 0.01 to 4.8.

[0039] The inventors of the present invention speculate that the reason why a semiconductor adhesive exhibiting the above DSC curve can be obtained by setting the molar ratio of the curing agent to the flux compound within the above range is as follows: As mentioned above, the thermosetting resin in the semiconductor adhesive reacts with the flux compound in the temperature range of 60 to 155°C. However, it is speculated that when the molar ratio of the curing agent to the flux compound is within the above range, the flux compound can form a salt with the curing agent and stabilize before reacting with the thermosetting resin. Therefore, it is speculated that the reaction between the thermosetting resin and the flux compound is suppressed, resulting in a semiconductor adhesive exhibiting the above DSC curve.

[0040] Hereinafter, each component constituting the adhesive for semiconductor use of this embodiment will be described.

[0041] (a) Thermoplastic resin The component (a) is not particularly limited, but examples thereof include phenoxy resin, polyimide resin, polyamide resin, polycarbodiimide resin, cyanate ester resin, acrylic resin, polyester resin, polyethylene resin, polyethersulfone resin, polyetherimide resin, polyvinyl acetal resin, urethane resin, and acrylic rubber. Among these, from the viewpoint of excellent heat resistance and film formability, phenoxy resin, polyimide resin, acrylic resin, acrylic rubber, cyanate ester resin, and polycarbodiimide resin are preferred, and phenoxy resin, polyimide resin, and acrylic resin are more preferred. These components (a) can be used alone or as a mixture or copolymer of two or more.

[0042] The weight-average molecular weight (Mw) of component (a) is preferably 10,000 or more, more preferably 40,000 or more, and even more preferably 60,000 or more. Such component (a) can further improve the film-formability and heat resistance of the adhesive. Furthermore, a weight-average molecular weight of 10,000 or more can easily impart flexibility to a film-shaped semiconductor adhesive, thereby making it easier to achieve even better processability. Furthermore, the weight-average molecular weight of component (a) is preferably 1,000,000 or less, and more preferably 500,000 or less. Such component (a) reduces the viscosity of the film, improving its embeddability into bumps and enabling even more void-free mounting. From these viewpoints, the weight-average molecular weight of component (a) is preferably 10,000 to 1,000,000, more preferably 40,000 to 500,000, and even more preferably 60,000 to 500,000.

[0043] In this specification, the weight average molecular weight refers to a weight average molecular weight measured using GPC (gel permeation chromatography) in terms of polystyrene. An example of the measurement conditions for the GPC method is shown below. Apparatus: HCL-8320GPC, UV-8320 (product name, manufactured by Tosoh Corporation), or HPLC-8020 (product name, manufactured by Tosoh Corporation) Column: TSKgel superMultiporeHZ-M x 2, or 2 pieces of GMHXL + 1 piece of G-2000XL Detector: RI or UV detector Column temperature: 25 to 40°C Eluent: A solvent that dissolves polymer components is selected. Examples of solvents include tetrahydrofuran (THF), N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMA), N-methylpyrrolidone (NMP), and toluene. When a polar solvent is selected, the phosphoric acid concentration may be adjusted to 0.05 to 0.1 mol / L (usually 0.06 mol / L) and the LiBr concentration may be adjusted to 0.5 to 1.0 mol / L (usually 0.63 mol / L). Flow rate: 0.30~1.5mL / min Standard material: polystyrene

[0044] (a) Component content C a (b) component content C b Ratio of C b / C a (mass ratio) is preferably 0.01 or more, more preferably 0.1 or more, even more preferably 1 or more, and is preferably 5 or less, more preferably 4.5 or less, even more preferably 4 or less. b / C a By making the ratio C 0.01 or more, better curing properties and adhesive strength can be obtained, and b / C a By setting the ratio C to 5 or less, better film formability can be obtained. b / C a is preferably 0.01 to 5, more preferably 0.1 to 4.5, and even more preferably 1 to 4.

[0045] From the viewpoint of improving connection reliability, the glass transition temperature of component (a) is preferably -50°C or higher, more preferably -40°C or higher, and even more preferably -30°C or higher. From the viewpoint of lamination, the glass transition temperature is preferably 220°C or lower, more preferably 200°C or lower, and even more preferably 180°C or lower. The glass transition temperature of component (a) is preferably -50 to 220°C, more preferably -40 to 200°C, and even more preferably -30 to 180°C. A semiconductor adhesive containing such component (a) can further reduce the amount of wafer warpage during a wafer-level mounting process, and can further improve the heat resistance and film formability of the semiconductor adhesive. The glass transition temperature of component (a) can be measured using a differential scanning calorimeter (DSC).

[0046] The content of component (a) is preferably 30% by mass or less, more preferably 25% by mass or less, and even more preferably 20% by mass or less, based on the total solid content of the semiconductor adhesive. When the content of component (a) is 30% by mass or less, the semiconductor adhesive can achieve good reliability during temperature cycle testing, and can maintain good adhesive strength at reflow temperatures of around 260°C even after moisture absorption. Furthermore, the content of component (a) is preferably 1% by mass or more, more preferably 3% by mass or more, and even more preferably 5% by mass or more, based on the total solid content of the semiconductor adhesive. When the content of component (a) is 1% by mass or more, the semiconductor adhesive can further reduce the amount of wafer warpage during wafer-level mounting processes, and can further improve the heat resistance and film formability of the semiconductor adhesive. When the content of component (a) is 5% by mass or more, the occurrence of burrs and chips during wafer contour processing can be suppressed. From the above viewpoints, and from the viewpoint of easily imparting flexibility to the film-shaped semiconductor adhesive and easily achieving even better processability, the content of component (a) is preferably 1 to 30 mass%, more preferably 3 to 30 mass%, and even more preferably 5 to 30 mass%, based on the total solid content of the semiconductor adhesive. Note that the "total solid content of the semiconductor adhesive" refers to the total amount of the semiconductor adhesive minus the amount of solvent contained in the semiconductor adhesive. In this specification, the "total solid content of the semiconductor adhesive" may also be referred to as the "total amount of components (a) to (e)."

[0047] (b) Thermosetting resin Component (b) can be any component having two or more reactive groups in the molecule. When the semiconductor adhesive contains a thermosetting resin, the adhesive can be cured by heating, and the cured adhesive exhibits high heat resistance and adhesive strength to the chip, resulting in excellent reflow resistance.

[0048] Examples of component (b) include epoxy resins, phenolic resins, imide resins, urea resins, melamine resins, silicone resins, (meth)acrylic compounds, and vinyl compounds. Among these, epoxy resins, phenolic resins, and imide resins are preferred, with epoxy resins and imide resins being more preferred, and epoxy resins being even more preferred, from the viewpoint of excellent heat resistance (reflow resistance) and storage stability. These components (b) can be used alone or as a mixture or copolymer of two or more. Among conventional semiconductor adhesives, particularly when the thermosetting resin is an epoxy resin, melamine resin, or urea resin, reaction with the flux compound (described below) tends to proceed easily in the temperature range of 60 to 155°C, resulting in partial curing before overall curing. However, in the present embodiment, even when the thermosetting resin contains at least one resin selected from the group consisting of epoxy resins, melamine resins, and urea resins, such reaction and partial curing are unlikely to occur.

[0049] Examples of epoxy resins and imide resins that can be used include bisphenol A epoxy resins, bisphenol F epoxy resins, naphthalene epoxy resins, phenol novolac epoxy resins, cresol novolac epoxy resins, phenol aralkyl epoxy resins, biphenyl epoxy resins, triphenylmethane epoxy resins, dicyclopentadiene epoxy resins, and various polyfunctional epoxy resins, nadimide resins, allylnadimide resins, maleimide resins, amide-imide resins, imide acrylate resins, various polyfunctional imide resins, and various polyimide resins. These can be used alone or in combination of two or more.

[0050] In order to prevent component (b) from decomposing and generating volatile components when connected at high temperatures, it is preferable to use one whose thermal weight loss rate at 250°C is 5% or less when the temperature at the time of connection is 250°C, and it is preferable to use one whose thermal weight loss rate at 300°C is 5% or less when the temperature at the time of connection is 300°C.

[0051] It is preferable that component (b) contains substantially no epoxy resin that is liquid at 35°C (for example, the content of epoxy resin that is liquid at 35°C is 0.1 part by mass or less per 100 parts by mass of component (b)). In this case, mounting can be performed without the liquid epoxy resin decomposing or volatilizing during thermocompression bonding, and outgassing contamination around the chip is suppressed, making it easier to achieve even better package throughput.

[0052] The content of component (b) is, for example, 5% by mass or more, preferably 15% by mass or more, and more preferably 30% by mass or more, based on the total solid content of the adhesive for semiconductors. The content of component (b) is, for example, 80% by mass or less, preferably 70% by mass or less, and more preferably 60% by mass or less, based on the total solid content of the adhesive for semiconductors. The content of component (b) is, for example, 5 to 80% by mass, preferably 15 to 70% by mass, and more preferably 30 to 60% by mass, based on the total solid content of the adhesive for semiconductors.

[0053] (c) Hardener Component (c) may be a curing agent capable of forming a salt with the fluxing agent described below. Examples of component (c) include amine-based curing agents (amines) and imidazole-based curing agents (imidazoles). When component (c) contains an amine-based or imidazole-based curing agent, it exhibits flux activity that suppresses the formation of an oxide film at the connection, thereby improving connection reliability and insulation reliability. Furthermore, when component (c) contains an amine-based or imidazole-based curing agent, storage stability is further improved and decomposition or deterioration due to moisture absorption tends to be less likely to occur. Furthermore, when component (c) contains an amine-based or imidazole-based curing agent, it becomes easier to adjust the curing speed, and the fast curing property makes it easier to achieve short-time connections for the purpose of improving productivity.

[0054] Each curing agent will be described below.

[0055] (i) Amine-based curing agents As the amine-based curing agent, for example, dicyandiamide can be used.

[0056] The content of the amine-based curing agent is preferably 0.1 parts by mass or more per 100 parts by mass of the component (b). Furthermore, the content of the amine-based curing agent is preferably 10 parts by mass or less, more preferably 5 parts by mass or less, per 100 parts by mass of the component (b). When the content of the amine-based curing agent is 0.1 parts by mass or more, curability tends to improve, while when it is 10 parts by mass or less, the semiconductor adhesive does not harden before a metal bond is formed, and connection defects tend to be less likely to occur. From these viewpoints, the content of the amine-based curing agent is preferably 0.1 to 10 parts by mass, more preferably 0.1 to 5 parts by mass, per 100 parts by mass of the component (b).

[0057] (ii) Imidazole-based curing agents Examples of imidazole curing agents include 2-phenylimidazole, 2-phenyl-4-methylimidazole, 1-benzyl-2-methylimidazole, 1-benzyl-2-phenylimidazole, 1-cyanoethyl-2-undecylimidazole, 1-cyano-2-phenylimidazole, 1-cyanoethyl-2-undecylimidazole trimellitate, 1-cyanoethyl-2-phenylimidazolium trimellitate, 2,4-diamino-6-[2'-methylimidazolyl-(1')]-ethyl-s-triazine, and 2,4-diamino-6-[2'-methylimidazolyl-(1')]-ethyl-s-triazine. -[2'-undecylimidazolyl-(1')]-ethyl-s-triazine, 2,4-diamino-6-[2'-ethyl-4'-methylimidazolyl-(1')]-ethyl-s-triazine, 2,4-diamino-6-[2'-methylimidazolyl-(1')]-ethyl-s-triazine isocyanuric acid adduct, 2-phenylimidazole isocyanuric acid adduct, 2-phenyl-4,5-dihydroxymethylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole, and adducts of epoxy resins and imidazoles. Among these, from the viewpoints of excellent curing properties, storage stability, and connection reliability, 1-cyanoethyl-2-undecylimidazole, 1-cyano-2-phenylimidazole, 1-cyanoethyl-2-undecylimidazole trimellitate, 1-cyanoethyl-2-phenylimidazolium trimellitate, 2,4-diamino-6-[2'-methylimidazolyl-(1')]-ethyl-s-triazine, 2,4-diamino-6-[2'-ethyl-4'-methylimidazolyl-(1')]-ethyl-s-triazine, 2,4-diamino-6-[2'-methylimidazolyl-(1')]-ethyl-s-triazine isocyanuric acid adduct, 2-phenylimidazole isocyanuric acid adduct, 2-phenyl-4,5-dihydroxymethylimidazole, and 2-phenyl-4-methyl-5-hydroxymethylimidazole are preferred. These may be used alone or in combination of two or more kinds, and may also be microencapsulated to form latent curing agents.

[0058] The content of the imidazole curing agent is preferably 0.1 parts by mass or more per 100 parts by mass of component (b). Furthermore, the content of the imidazole curing agent is preferably 10 parts by mass or less, more preferably 5 parts by mass or less, and even more preferably 2.3 parts by mass or less per 100 parts by mass of component (b). When the content of the imidazole curing agent is 0.1 parts by mass or more, curability tends to be improved. When the content of the imidazole curing agent is 10 parts by mass or less, the semiconductor adhesive does not harden before a metal bond is formed, which makes it less likely to cause poor connection and also helps to suppress the generation of voids in a curing process under a pressurized atmosphere. From these viewpoints, the content of the imidazole curing agent is preferably 0.1 to 10 parts by mass, more preferably 0.1 to 5 parts by mass, and even more preferably 0.1 to 2.3 parts by mass per 100 parts by mass of component (b).

[0059] Component (c) can be used alone or in a mixture of two or more. For example, an imidazole-based curing agent can be used alone or together with an amine-based curing agent. Other curing agents that function as curing agents for component (b) can also be used as component (c).

[0060] The content of component (c) is preferably 0.5 parts by mass or more per 100 parts by mass of component (b). Furthermore, the content of component (c) is preferably 20 parts by mass or less, more preferably 6 parts by mass or less, and even more preferably 4 parts by mass or less per 100 parts by mass of component (b). When the content of component (c) is 0.5 parts by mass or more, curing tends to proceed sufficiently. When the content of component (c) is 20 parts by mass or less, curing tends to proceed more rapidly, preventing an increase in the number of reaction sites, shortening of molecular chains, remaining unreacted groups, and other factors that could reduce reliability. Furthermore, it tends to prevent the formation of voids during curing under a pressurized atmosphere. From these perspectives, the content of component (c) is preferably 0.2 to 20 parts by mass, more preferably 0.5 to 6 parts by mass, and even more preferably 0.5 to 4 parts by mass per 100 parts by mass of component (b).

[0061] The content of component (c) is preferably 0.5% by mass or more, based on the total solid content of the semiconductor adhesive. Furthermore, the content of component (c) is preferably 2.3% by mass or less, more preferably 2.0% by mass or less, and even more preferably 1.5% by mass or less, based on the total solid content of the semiconductor adhesive. When the content of component (c) is 0.5% by mass or more, curing tends to proceed sufficiently. When the content of component (c) is 2.3% by mass or less, rapid curing is suppressed, which tends to prevent an increase in reactive sites and a decrease in reliability due to shortened molecular chains or remaining unreacted groups. Additionally, it tends to prevent voids from remaining during curing under a pressurized atmosphere. From these viewpoints, the content of component (c) is preferably 0.5 to 2.3% by mass, more preferably 0.5 to 2.0% by mass, and even more preferably 0.5 to 1.5% by mass, based on the total solid content of the semiconductor adhesive.

[0062] When the adhesive for semiconductors contains an amine-based curing agent as component (c), excellent curing properties are exhibited by the curing reaction with the epoxy resin, and the reflow resistance of the semiconductor device can be further improved.

[0063] (d) Flux compounds Component (d) is a compound with flux activity (activity to remove oxides and impurities), such as an organic acid. By including component (d) in a semiconductor adhesive, oxide films on metals at connection points and coatings caused by OSP treatment can be removed, making it easier to achieve excellent connection reliability. As component (d), one type of flux compound (e.g., organic acid) may be used alone, or two or more types of flux compounds (e.g., organic acids) may be used in combination.

[0064] Component (d) has at least one carboxyl group as an acid group. When component (d) is a compound having a carboxyl group (e.g., carboxylic acid), even better connection reliability is likely to be achieved. Because component (d) is a compound having a carboxyl group (e.g., carboxylic acid), from the viewpoint of making it easier to achieve the effects of the present invention, component (b) is preferably at least one thermosetting resin selected from the group consisting of epoxy resins, urethane resins, and urea resins, and component (c) is preferably at least one curing agent selected from the group consisting of amine-based curing agents and imidazole-based curing agents. Component (d) may further have an acid group other than a carboxyl group.

[0065] Component (d) has a structure in which at least one electron-withdrawing group is substituted on the α-carbon of a carboxyl group. Examples of compounds having such a structure include compounds having a structure represented by the following general formula (1-1), (1-2), or (1-3). [ka] [ka] [ka]

[0066] In formulas (1-1) to (1-3), R 1 represents an electron-withdrawing group, and R 2 represents a hydrogen atom or an electron-withdrawing group.

[0067] Examples of electron-withdrawing groups include sulfonyl, nitro, cyano, halogen, and carbonyl groups. Component (d) may contain two or more types of electron-withdrawing groups. Furthermore, the α-carbon of the carboxyl group in component (d) may constitute a part of the electron-withdrawing group. For example, in the above formula (1-2), the α-carbon of the carboxyl group constitutes a part of the carbonyl group. That is, component (d) can be said to have a structure in which the electron-withdrawing group is directly bonded to the α-carbon of the carboxyl group, or a structure in which the α-carbon of the carboxyl group constitutes a part of the electron-withdrawing group. From the viewpoint of easily obtaining excellent flux activity and easily achieving the effects of the present invention, the electron-withdrawing group preferably contains at least one selected from the group consisting of a cyano group, a halogen group, and a carbonyl group, and more preferably contains a carbonyl group.

[0068] The component (d) may contain a compound represented by the following general formula (2-1) or (2-2). [ka] [ka]

[0069] In formulas (2-1) and (2-2), R 1 represents an electron-withdrawing group, and R 2 represents a hydrogen atom or an electron-withdrawing group, and R 3 represents a hydrogen atom or a monovalent organic group, and n represents an integer of 0 to 15. 3 may be the same or different from each other.

[0070] The component (d) may contain a compound represented by the following general formula (3-1) or (3-2). [ka] [ka]

[0071] In formulas (3-1) and (3-2), R 1 represents an electron-withdrawing group, and R 2 represents a hydrogen atom or an electron-withdrawing group, and R 3 represents a hydrogen atom or a monovalent organic group, and m represents an integer of 0 to 10.

[0072] In formulas (2-1), (2-2), (3-1) and (3-2), R 3 may be a hydrogen atom or an alkyl group, and may be a hydrogen atom or an alkyl group having 1 to 10 carbon atoms. n may be an integer of 1 to 15. m may be an integer of 0 to 15.

[0073] Component (d) is preferably a compound having 1 to 3 acid groups, more preferably a compound having 1 to 3 carboxyl groups as the acid groups. Component (d) preferably contains at least one selected from the group consisting of monocarboxylic acids, dicarboxylic acids, and tricarboxylic acids. When component (d) having 1 to 3 carboxyl groups is used, the increase in viscosity of the adhesive for semiconductors during storage, connection work, etc. can be further suppressed compared to when a compound having four or more carboxyl groups is used, thereby further improving the connection reliability of semiconductor devices.

[0074] Component (d) is preferably a compound having two carboxyl groups (dicarboxylic acid). Compared with compounds having one carboxyl group (monocarboxylic acid), dicarboxylic acids are less likely to volatilize even at high temperatures during connection, further reducing the occurrence of voids. Furthermore, the use of a compound having two carboxyl groups can further reduce the increase in viscosity of the semiconductor adhesive during storage, connection work, etc., compared with compounds having three or more carboxyl groups, thereby further improving the connection reliability of semiconductor devices.

[0075] The melting point of component (d) is preferably 25°C or higher, more preferably 60°C or higher, even more preferably 100°C or higher, and preferably 170°C or lower, more preferably 150°C or lower, and even more preferably 130°C or lower. When the melting point of component (d) is 170°C or lower, flux activity is likely to be fully exhibited before the curing reaction between the thermosetting resin and the curing agent occurs. Therefore, when a semiconductor adhesive containing such component (d) is used, component (d) melts upon chip mounting, removing the oxide film on the solder surface, thereby achieving a semiconductor device with even more excellent connection reliability. Furthermore, when the melting point of component (d) is 25°C or higher, the reaction is less likely to start at room temperature or on a high-temperature stage, resulting in even more excellent storage stability. From these perspectives, the melting point of component (d) is preferably 25 to 170°C, more preferably 60 to 150°C, and even more preferably 100 to 130°C.

[0076] (d) The melting point of a component can be measured using a standard melting point measurement device. The sample for which the melting point is to be measured must be pulverized into a fine powder and a small amount must be used to minimize temperature deviations within the sample. A capillary tube with one end closed is often used as the sample container, but some measurement devices use a container sandwiched between two microscope cover glasses. A rapid increase in temperature creates a temperature gradient between the sample and the thermometer, resulting in measurement errors. Therefore, when measuring the melting point, it is desirable to increase the temperature at a rate of less than 1°C per minute.

[0077] As mentioned above, samples for melting point measurement are prepared as fine powders. Because of diffuse reflection from the surface, the sample is opaque before melting. The temperature at which the sample begins to become transparent is typically used as the lower limit of the melting point, and the temperature at which the sample is completely melted is typically used as the upper limit. While various types of measurement devices exist, the most classic is a double-tube thermometer equipped with a capillary tube filled with the sample, which is then heated in a hot bath. A highly viscous liquid, often concentrated sulfuric acid or silicone oil, is used to attach the capillary tube to the double-tube thermometer, and the sample is placed near the reservoir at the tip of the thermometer. Alternatively, a melting point measurement device can be used that uses a metal heat block to heat the sample, adjusting the heat while measuring the light transmittance, thereby automatically determining the melting point.

[0078] In this specification, a melting point of 170°C or lower means that the upper limit of the melting point is 170°C or lower, and a melting point of 25°C or higher means that the lower limit of the melting point is 25°C or higher.

[0079] Specific examples of component (d) include 2-fluoropropionic acid, fluoromalonaldehyde acid, 2-fluoroisobutyric acid, 3-amino-2-fluoropropanoic acid, 2,2-difluoropropionic acid, 2-bromo-2-fluoropropanoic acid, 1-fluorocyclopropanecarboxylic acid, 2-fluoro-3-methylbutanoic acid, chloroacetic acid, 2-chloroacrylic acid, 2-chloropropionic acid, chlorofluoroacetic acid, dichloroacetic acid, bromochloroacetic acid, chloroiodoacetic acid, bromoacetic acid, 2-bromoacrylic acid, 2-bromopropionic acid, dibromoacetic acid, bromoiodoacetic acid, glucoxylic acid, pyruvic acid, oxamic acid, oxalic acid, 2-oxopropanedioic acid, 2-bromopropanedioic acid, oxaloacetic acid, and cyanoacetic acid. Acid, 1-cyano-1-cyclopropanoic acid, α-cyanocinnamic acid, α-cyano-3-hydroxycinnamic acid, α-cyano-4-hydroxycinnamic acid, 2-oxobutyric acid, 2-oxopentanoic acid, N,N-dimethyloxamic acid, 4-methyl-2-oxopentanoic acid, 3,3-dimethyl-2-oxobutyric acid, 3-methyl-2-oxopentanoic acid, phenylglyoxylic acid, phenylpyruvic acid, 3-bromo-2-oxopropionic acid, 2-oxo-4-phenylbutyric acid, 4-hydroxyphenylpyruvic acid, (2,6-dimethylanilino)(oxo)acetic acid, 4-hydroxy-3-methoxyphenylpyruvic acid, potassium trihydrogen dioxalate dihydrate, 2-oxoglutaric acid (α-ketoglutaric acid), and the like. Among these, from the viewpoint of easily obtaining excellent flux activity and easily achieving the effects of the present invention, oxalic acid, 2-oxopropanedioic acid, 2-bromopropanedioic acid, oxaloacetic acid, α-cyano-3-hydroxycinnamic acid, α-cyano-4-hydroxycinnamic acid, 4-hydroxy-3-methoxyphenylpyruvic acid, and 2-oxoglutaric acid are preferred, and 2-oxoglutaric acid is particularly preferred. These may be used alone or in combination of two or more.

[0080] The content of component (d) is preferably 0.1% by mass or more, based on the total solid content of the semiconductor adhesive. Furthermore, the content of component (d) is preferably 10% by mass or less, more preferably 5% by mass or less, and even more preferably 2% by mass or less, based on the total solid content of the semiconductor adhesive. From the viewpoint of connection reliability and reflow resistance during semiconductor device fabrication, the content of component (d) is preferably 0.1 to 10% by mass, more preferably 0.1 to 5% by mass, and even more preferably 0.1 to 2% by mass, based on the total solid content of the semiconductor adhesive. When a compound having flux activity corresponds to components (a) to (c), the content of component (d) is calculated assuming that the compound also corresponds to component (d). The same applies to the number of moles of acid groups, etc., described below.

[0081] In this embodiment, the ratio of the number of moles of acid groups in the total amount of component (d) to the number of moles of reactive groups in the total amount of component (c) is preferably 0.01 or more and 4.8 or less, more preferably 0.1 or more, even more preferably 0.5 or more, more preferably 4.0 or less, even more preferably 3.0 or less.

[0082] When component (d) contains at least one selected from the group consisting of monocarboxylic acids, dicarboxylic acids, and tricarboxylic acids, the ratio of the number of moles of acid groups in the total amount of component (d) to the number of moles of reactive groups in the total amount of component (c) is 0.01 to 4.8, and the ratio of the number of moles of monocarboxylic acids to the number of moles of reactive groups in the total amount of component (c) is 0.01 to 4.8, and the ratio of the number of moles of dicarboxylic acids to the number of moles of reactive groups in the total amount of component (c) is 0.01 to 2.4, It is preferable that the ratio of the number of moles of tricarboxylic acid to the number of moles of reactive groups in the total amount of component (c) is 0.01 to 1.6, and more preferably the ratio of the number of moles of monocarboxylic acid to the number of moles of reactive groups in the total amount of component (c) is 0.5 to 3.0, the ratio of the number of moles of dicarboxylic acid to the number of moles of reactive groups in the total amount of component (c) is 0.25 to 1.5, and the ratio of the number of moles of tricarboxylic acid to the number of moles of reactive groups in the total amount of component (c) is 0.5 / 3 to 1.0.

[0083] (e) Filler The semiconductor adhesive of this embodiment may contain a filler (component (e)) as needed. Component (e) can control the viscosity of the semiconductor adhesive, the physical properties of the cured product of the semiconductor adhesive, and the like. Specifically, component (e) can, for example, suppress the generation of voids during connection, reduce the moisture absorption rate of the cured product of the semiconductor adhesive, and the like.

[0084] The component (e) can be an insulating inorganic filler, whiskers, a resin filler, etc. The component (e) can be used alone or in combination of two or more.

[0085] Examples of insulating inorganic fillers include glass, silica, alumina, titanium oxide, carbon black, mica, and boron nitride. Among these, silica, alumina, titanium oxide, and boron nitride are preferred, and silica, alumina, and boron nitride are more preferred.

[0086] Whiskers include, for example, aluminum borate, aluminum titanate, zinc oxide, calcium silicate, magnesium sulfate, and boron nitride.

[0087] Examples of the resin filler include fillers made of resins such as polyurethane and polyimide.

[0088] Resin fillers have a smaller thermal expansion coefficient than organic components (epoxy resins, curing agents, etc.), and therefore are excellent in improving connection reliability. Resin fillers also allow for easy adjustment of the viscosity of semiconductor adhesives. Resin fillers also have a superior stress-relieving function compared to inorganic fillers.

[0089] Inorganic fillers have a smaller coefficient of thermal expansion than resin fillers, and therefore can reduce the coefficient of thermal expansion of adhesive compositions. In addition, inorganic fillers are often general-purpose products with controlled particle sizes, making them suitable for viscosity adjustment.

[0090] Since the resin filler and the inorganic filler each have advantageous effects, either one may be used depending on the application, or both may be mixed and used to exhibit the functions of both.

[0091] There are no particular restrictions on the shape, particle size, or content of component (e). Component (e) may also have its physical properties appropriately adjusted by surface treatment.

[0092] The content of component (e) is preferably 10% by mass or more, more preferably 15% by mass or more, and preferably 80% by mass or less, more preferably 60% by mass or less, based on the total solid content of the adhesive for semiconductors. The content of component (e) is preferably 10 to 80% by mass, more preferably 15 to 60% by mass, based on the total solid content of the adhesive for semiconductors.

[0093] Component (e) is preferably made of an insulating material, which makes it easier to prevent a decrease in insulation reliability (particularly HAST resistance) compared to when component (e) is made of a conductive material (e.g., solder, gold, silver, copper, etc.).

[0094] (Other ingredients) The semiconductor adhesive of this embodiment may contain additives such as antioxidants, silane coupling agents, titanium coupling agents, leveling agents, and ion trapping agents. These may be used alone or in combination of two or more. The amounts of these additives may be adjusted appropriately so that the effects of each additive are exerted.

[0095] The semiconductor adhesive of this embodiment may be in the form of a film. In this case, workability can be improved when sealing gaps between a semiconductor chip and a wiring substrate or gaps between multiple semiconductor chips using a pre-applied method. An example of a method for producing a semiconductor adhesive (film-like adhesive) of this embodiment formed into a film is shown below.

[0096] First, components (a), (b), (c), and (d), as well as optional component (e), etc., are added to an organic solvent and dissolved or dispersed by stirring, mixing, kneading, etc. to prepare a resin varnish. The resin varnish is then applied to a release-treated substrate film using a knife coater, roll coater, applicator, etc., and the organic solvent is then removed by heating, thereby forming a film-like adhesive on the substrate film.

[0097] The thickness of the film adhesive is not particularly limited, but is preferably 0.5 to 1.5 times, more preferably 0.6 to 1.3 times, and even more preferably 0.7 to 1.2 times the height of the bumps before connection.

[0098] If the thickness of the film adhesive is 0.5 times or more the height of the bump, it is possible to sufficiently suppress the occurrence of voids due to unfilled adhesive, further improving connection reliability. Furthermore, if the thickness is 1.5 times or less, it is possible to sufficiently suppress the amount of adhesive extruded from the chip connection area during connection, thereby preventing adhesive from adhering to unnecessary areas. If the thickness of the film adhesive is more than 1.5 times, the bump must eliminate a large amount of adhesive, making electrical conduction failure more likely. Furthermore, in response to the weakening of bumps due to narrower pitches and more pins (reduced bump diameter), eliminating a large amount of resin is undesirable because it causes greater damage to the bumps.

[0099] Since the height of a bump is generally 5 to 100 μm, the thickness of the film adhesive is preferably 2.5 to 150 μm, and more preferably 3.5 to 120 μm.

[0100] The organic solvent used in preparing the resin varnish is preferably one that can uniformly dissolve or disperse each component, such as dimethylformamide, dimethylacetamide, N-methyl-2-pyrrolidone, dimethyl sulfoxide, diethylene glycol dimethyl ether, toluene, benzene, xylene, methyl ethyl ketone, tetrahydrofuran, ethyl cellosolve, ethyl cellosolve acetate, butyl cellosolve, dioxane, cyclohexanone, and ethyl acetate. These organic solvents can be used alone or in combination of two or more. The stirring, mixing, and kneading during the preparation of the resin varnish can be performed using, for example, a stirrer, a grinder, a three-roll mill, a ball mill, a bead mill, or a homodisper.

[0101] The substrate film is not particularly limited as long as it has heat resistance sufficient to withstand the heating conditions when volatilizing the organic solvent, and examples thereof include polyolefin films such as polypropylene film and polymethylpentene film, polyester films such as polyethylene terephthalate film and polyethylene naphthalate film, polyimide film, and polyetherimide film. The substrate film is not limited to a single layer made of these films, and may be a multilayer film made of two or more materials.

[0102] The drying conditions for volatilizing the organic solvent from the resin varnish applied to the substrate film are preferably conditions that allow the organic solvent to volatilize sufficiently, specifically, heating at 50 to 200°C for 0.1 to 90 minutes is preferred. The organic solvent is preferably removed to 1.5 mass% or less of the total amount of the film-like adhesive.

[0103] The adhesive for a semiconductor of this embodiment may also be formed directly on a wafer. Specifically, for example, the resin varnish may be spin-coated directly onto a wafer to form a film, and then the organic solvent may be removed to form a layer of the adhesive for a semiconductor directly on the wafer.

[0104] The minimum melt viscosity of the semiconductor adhesive of this embodiment is preferably 200 to 10,000 Pa·s, and more preferably 200 to 5,000 Pa·s, from the viewpoint of more easily eliminating voids during curing under a pressurized atmosphere and achieving even better reflow resistance. The minimum melt viscosity can be measured by the method described in the Examples. The temperature (melting temperature) at which the semiconductor adhesive exhibits the minimum melt viscosity is preferably 100 to 250°C, more preferably 120 to 230°C, and even more preferably 140 to 200°C.

[0105] From the viewpoint of facilitating temporary fixing of semiconductor chips in a temperature range of 60 to 170°C, the semiconductor adhesive of this embodiment preferably has a melt viscosity of 2000 to 30000 Pa·s at 80°C, preferably a melt viscosity of 400 to 20000 Pa·s at 130°C, and more preferably a melt viscosity of 4000 to 20000 Pa·s at 80°C and a melt viscosity of 400 to 5000 Pa·s at 130°C. The above melt viscosities can be measured by the method described in the Examples.

[0106] The semiconductor adhesive of the present embodiment described above can be suitably used in processes in which curing is performed by applying heat under a pressurized atmosphere, and can be particularly suitably used in processes in which multiple semiconductor chips are mounted and temporarily fixed on a mounting member (semiconductor chip, semiconductor wafer, wiring circuit board, etc.) via the semiconductor adhesive, and then cured and sealed all at once under pressurized conditions. When the semiconductor adhesive of the present embodiment is used in this process, voids within the adhesive are easily removed by pressure, making it easier to achieve even better reflow resistance.

[0107] <Semiconductor device> The semiconductor device of this embodiment is a semiconductor device in which the connection portions of a semiconductor chip and a wiring circuit board are electrically connected to each other, or a semiconductor device in which the connection portions of multiple semiconductor chips are electrically connected to each other. In this semiconductor device, at least a portion of the connection portions is sealed with a cured product of the semiconductor adhesive that has been cured by applying heat under a pressurized atmosphere. The semiconductor device of this embodiment will be described below with reference to Figures 1, 2, and 3. Figures 1, 2, and 3 are each a cross-sectional view showing one embodiment of a semiconductor device that can be manufactured by a method according to an embodiment described below.

[0108] FIG. 1 is a schematic cross-sectional view showing a COB-type connection between a semiconductor chip and a substrate. The semiconductor device 100 shown in FIG. 1 includes a semiconductor chip 1, a substrate 2 (wired circuit board), and an adhesive layer 40 interposed therebetween. In the semiconductor device 100, the semiconductor chip 1 includes a semiconductor chip body 10, wiring or bumps 15 disposed on the surface of the semiconductor chip body 10 facing the substrate 2, and solder 30 disposed on the wiring or bumps 15 as a connection portion. The substrate 2 includes a substrate body 20 and wiring or bumps 16 disposed on the surface of the substrate body 20 facing the semiconductor chip 1 as a connection portion. The solder 30 of the semiconductor chip 1 and the wiring or bumps 16 of the substrate 2 are electrically connected by metal bonding. The semiconductor chip 1 and the substrate 2 are flip-chip connected by the wiring or bumps 16 and the solder 30. The wiring or bumps 15, 16 and the solder 30 are sealed by the adhesive layer 40, thereby isolating them from the external environment.

[0109] 2 shows a COC type connection between semiconductor chips. The configuration of the semiconductor device 300 shown in FIG. 2 is the same as that of the semiconductor device 100, except that two semiconductor chips 1 are flip-chip connected via wiring or bumps 15 and solder 30.

[0110] In FIGS. 1 and 2, the connection portions such as wiring or bumps 15 may be metal films (for example, gold plating) called pads, or may be post electrodes (for example, copper pillars).

[0111] The semiconductor chip body 10 is not particularly limited, and various semiconductors can be used, such as elemental semiconductors composed of the same type of element, such as silicon and germanium, and compound semiconductors, such as gallium arsenide and indium phosphide.

[0112] The substrate 2 is not particularly limited as long as it is a wired circuit board, and examples that can be used include circuit boards in which wiring (wiring pattern) is formed by etching away unnecessary portions of a metal layer formed on the surface of an insulating substrate whose main component is glass epoxy, polyimide, polyester, ceramic, epoxy, bismaleimide triazine, etc.; circuit boards in which wiring (wiring pattern) is formed on the surface of the insulating substrate by metal plating, etc.; and circuit boards in which wiring (wiring pattern) is formed by printing a conductive material on the surface of the insulating substrate.

[0113] The materials of the connecting parts such as the wiring or bumps 15 and 16 and the solder 30 are mainly composed of gold, silver, copper, solder (the main component is, for example, tin-silver, tin-lead, tin-bismuth, tin-copper, tin-silver-copper), tin, nickel, etc., and may be composed of only a single component or multiple components. The connecting parts may have a structure in which these metals are laminated. Of the metal materials, copper and solder are relatively inexpensive and are preferable. From the viewpoint of improving connection reliability and suppressing warpage, the connecting parts may contain solder.

[0114] The pad material may be mainly composed of gold, silver, copper, solder (main components include, for example, tin-silver, tin-lead, tin-bismuth, tin-copper, and tin-silver-copper), tin, nickel, or the like, and may be composed of a single component or multiple components. The pad may have a structure in which these metals are laminated. From the viewpoint of connection reliability, the pad may contain gold or solder.

[0115] A metal layer mainly composed of gold, silver, copper, solder (main components of which may be, for example, tin-silver, tin-lead, tin-bismuth, or tin-copper), tin, nickel, or the like may be formed on the surface of the wiring or bumps 15, 16 (wiring pattern). This metal layer may be composed of only a single component, or may be composed of multiple components. The metal layer may have a structure in which multiple metal layers are stacked. The metal layer may contain relatively inexpensive copper or solder. From the viewpoint of improving connection reliability and suppressing warpage, the metal layer may contain solder.

[0116] Semiconductor devices (packages) such as those shown in FIG. 1 or 2 may be stacked and electrically connected using gold, silver, copper, solder (main components of which may be, for example, tin-silver, tin-lead, tin-bismuth, tin-copper, or tin-silver-copper), tin, nickel, or the like. The metal used for connection may be relatively inexpensive copper or solder. For example, as seen in TSV technology, an adhesive layer may be interposed between semiconductor chips for flip-chip connection or stacking, and holes may be formed through the semiconductor chips to connect to electrodes on the patterned surface.

[0117] FIG. 3 is a cross-sectional view showing another embodiment of a semiconductor device (a semiconductor chip stacking type embodiment (TSV)). In the semiconductor device 500 shown in FIG. 3, wiring or bumps 15 formed on an interposer body 50 serving as a substrate are connected to solder 30 of the semiconductor chip 1, thereby flip-chip connecting the semiconductor chip 1 and the interposer 5. An adhesive layer 40 is interposed between the semiconductor chip 1 and the interposer 5. On the surface of the semiconductor chip 1 opposite the interposer 5, semiconductor chips 1 are repeatedly stacked via wiring or bumps 15, solder 30, and adhesive layer 40. The wiring or bumps 15 on the pattern surfaces on the front and back of the semiconductor chip 1 are connected to each other by through electrodes 34 filled in holes that penetrate the interior of the semiconductor chip body 10. Copper, aluminum, etc. can be used as the material for the through electrodes 34.

[0118] Such TSV technology makes it possible to acquire signals from the backside of the semiconductor chip, which is not normally used. Furthermore, because the through electrodes 34 are passed vertically through the semiconductor chip 1, the distance between opposing semiconductor chips 1 and between the semiconductor chip 1 and the interposer 5 can be shortened, enabling flexible connections. In such TSV technology, the adhesive layer can be used as a sealing material between opposing semiconductor chips 1 and between the semiconductor chip 1 and the interposer 5.

[0119] <Method of manufacturing a semiconductor device> One embodiment of a method for manufacturing a semiconductor device includes a lamination step of laminating a first member having a connection portion and a second member having a connection portion via a semiconductor adhesive so that the connection portion of the first member faces the connection portion of the second member, and a sealing step of curing the semiconductor adhesive by applying heat under a pressurized atmosphere and sealing at least a portion of the connection portion with the cured semiconductor adhesive. Here, the first member is, for example, a wiring circuit board, a semiconductor chip, or a semiconductor wafer, and the second member is a semiconductor chip. In the sealing step, the laminate obtained in the lamination step is heated under a pressurized atmosphere to a temperature equal to or higher than the melting point of the opposing connection portions, thereby joining the opposing connection portions so that they are electrically connected.

[0120] When the first component is a semiconductor chip, the stacking process includes, for example, a process of arranging a plurality of semiconductor chips on a stage, and a temporary fixing process of sequentially placing other semiconductor chips on each of the plurality of semiconductor chips arranged on the stage via a semiconductor adhesive while heating the stage, thereby obtaining a plurality of laminates (temporary fixed bodies) in which the semiconductor chips, the semiconductor adhesive, and the other semiconductor chips are stacked in this order.

[0121] When the first component is a wiring circuit board or a semiconductor wafer having a plurality of semiconductor chips as a substrate, the stacking process includes, for example, a step of placing the wiring circuit board or the semiconductor wafer on a stage, and a temporary fixing step of sequentially placing a plurality of semiconductor chips on the wiring circuit board or the semiconductor wafer placed on the stage via a semiconductor adhesive while heating the stage, to obtain a laminate (temporary fixed body) in which the wiring circuit board, the semiconductor adhesive, and a plurality of the semiconductor chips are stacked in this order, or a laminate (temporary fixed body) in which the semiconductor wafer, the semiconductor adhesive, and a plurality of the semiconductor chips are stacked in this order.

[0122] In the temporary fixing step, for example, first, a semiconductor adhesive is placed on a first member or a second member (for example, a film-like semiconductor adhesive is attached), and then, the individual semiconductor chips on the dicing tape are picked up and adsorbed onto a crimping tool (a crimping head) of a crimping machine, and temporarily fixed to a wiring circuit board, another semiconductor chip, or a semiconductor wafer.

[0123] The method for disposing the semiconductor adhesive is not particularly limited, and for example, when the semiconductor adhesive is in film form, methods such as heat pressing, roll lamination, and vacuum lamination may be used. The area and thickness of the semiconductor adhesive to be disposed are appropriately set depending on the sizes of the first and second members, the height of the connection portions (bumps), etc. The semiconductor adhesive may be disposed on a semiconductor chip, or a semiconductor wafer on which the semiconductor adhesive has been disposed may be diced and then separated into individual semiconductor chips.

[0124] The temporary fixing process requires alignment to electrically connect the connecting parts, so a crimping machine such as a flip-chip bonder is generally used.

[0125] When the bonding tool picks up the semiconductor chip for temporary fixation, it is preferable that the bonding tool be kept at a low temperature so as not to transfer heat to the semiconductor adhesive on the semiconductor chip. On the other hand, during the bonding (temporary bonding), it is preferable that the semiconductor chip be heated to a high temperature so as to increase the fluidity of the semiconductor adhesive and efficiently eliminate trapped voids. However, heating to a temperature lower than the initiation temperature of the curing reaction of the semiconductor adhesive is preferable. To shorten the cooling time, it is preferable that the difference between the temperature of the bonding tool when picking up the semiconductor chip and the temperature of the bonding tool when temporary fixation is small. This temperature difference is preferably 100°C or less, more preferably 60°C or less, and even more preferably substantially 0°C. If the temperature difference is 100°C or more, it takes a long time for the bonding tool to cool, which tends to reduce productivity. The initiation temperature of the curing reaction of the semiconductor adhesive refers to the onset temperature measured using a DSC (PerkinElmer, DSC-Pyirs1) with a sample weight of 10 mg, a heating rate of 10°C / min, and an air or nitrogen atmosphere.

[0126] The load applied for temporary fixation is appropriately set taking into consideration the number of connection portions (bumps), absorbing variations in the height of the connection portions (bumps), and controlling the amount of deformation of the connection portions (bumps). In the temporary fixation process, it is preferable that the opposing connection portions are in contact with each other after pressure bonding (pre-pressure bonding). If the connection portions are in contact with each other after pressure bonding, metal bonds are more likely to be formed at the connection portions during pressure bonding (full pressure bonding) in the sealing process, and there is also a tendency for the semiconductor adhesive to be less likely to be trapped. The load is preferably large to eliminate voids and ensure contact at the connection portions; for example, a load of 0.0001 N to 0.2 N per connection portion (e.g., bump) is preferred, more preferably 0.0005 to 0.15 N, and even more preferably 0.001 to 0.1 N.

[0127] From the viewpoint of improving productivity, the shorter the pressure-bonding time in the temporary fixing step, the more preferable, and may be, for example, 5 seconds or less, 3 seconds or less, or 2 seconds or less.

[0128] The heating temperature of the stage is lower than the melting point of the connecting portion of the first member and the melting point of the connecting portion of the second member, and may typically be 60 to 150° C. or 70 to 100° C. Heating at such a temperature can efficiently eliminate voids trapped in the adhesive for semiconductors.

[0129] The temperature of the pressure bonding tool during temporary fixing is preferably set so that the temperature difference between it and the temperature of the pressure bonding tool used when picking up the semiconductor chip is small, as described above, and may be, for example, 80 to 350°C, or 100 to 170°C.

[0130] When the lamination process includes the temporary fixing process, the sealing process following the temporary fixing process may involve collectively curing the semiconductor adhesive in multiple laminates or in a laminate including multiple semiconductor chips to seal multiple connections. The sealing process joins opposing connections by metal bonding, and typically fills gaps between the connections with the semiconductor adhesive. The sealing process is performed using an apparatus capable of heating above the melting point of the metal in the connections and applying pressure. Examples of such an apparatus include a pressure reflow furnace and a pressure oven.

[0131] The heating temperature (connection temperature) in the sealing process is preferably set to a temperature equal to or higher than the melting point of at least one of the metals in the opposing connection parts (e.g., bump-bump, bump-pad, bump-wiring). For example, if the metal in the connection part is solder, the temperature is preferably 200°C or higher and 450°C or lower. If the heating temperature is low, the metal in the connection part may not melt, and a sufficient metal bond may not be formed. If the heating temperature is too high, the effect of void suppression may become relatively small, and the solder may be more likely to splash.

[0132] When pressure is applied to bond the connection portions using a crimping machine, the heat of the crimping machine is not easily transferred to the semiconductor adhesive (fillet) that protrudes from the side of the connection portion. Therefore, after the crimping (main crimping), a heat treatment is often required to sufficiently promote the curing of the semiconductor adhesive. Therefore, it is preferable to apply pressure in the sealing process by atmospheric pressure in a pressure reflow oven, pressure oven, or the like, rather than by a crimping machine. Pressure application by atmospheric pressure allows heat to be applied to the entire structure, shortening or eliminating the heat treatment after the crimping (main crimping), thereby improving productivity. Furthermore, pressure application by atmospheric pressure makes it easier to simultaneously perform the main crimping of multiple laminates (temporary fixtures) or laminates (temporary fixtures) comprising multiple temporarily fixed semiconductor chips. Furthermore, pressure application by atmospheric pressure is preferable to direct pressure application using a crimping machine from the viewpoint of fillet suppression. Fillet suppression is important in light of the trend toward miniaturization and high density of semiconductor devices.

[0133] The atmosphere in which pressure bonding is carried out in the sealing step is not particularly limited, but an atmosphere containing air, nitrogen, formic acid, or the like is preferred.

[0134] The pressure for crimping in the sealing step is set appropriately depending on the size and number of components to be connected. The pressure may be, for example, above atmospheric pressure and 1 MPa or less. A higher pressure is preferable from the viewpoint of suppressing voids and improving connectivity, while a lower pressure is preferable from the viewpoint of suppressing fillets. Therefore, the pressure is more preferably 0.05 to 0.5 MPa.

[0135] The crimping time varies depending on the metal constituting the connection, but from the viewpoint of improving productivity, the shorter the time, the better. When the connection is a solder bump, the connection time is preferably 20 seconds or less, more preferably 10 seconds or less, and even more preferably 5 seconds or less. When the metal connection is copper-copper or copper-gold, the connection time is preferably 60 seconds or less.

[0136] When multiple semiconductor chips are stacked three-dimensionally, such as in a semiconductor device with a TSV structure, the multiple semiconductor chips may be stacked one by one and temporarily fixed in place, and then the stacked multiple semiconductor chips may be heated and pressurized together to obtain the semiconductor device. [Example]

[0137] The present disclosure will be described in more detail below using examples, but the present disclosure is not limited to these examples.

[0138] The compounds used in each of the examples and comparative examples are as follows. (a) Component: Thermoplastic resin Polyurethane (manufactured by DIC Covestro Polymer Co., Ltd., product name "T-8175N", Tg: -23°C, Mw: 120000) Phenoxy resin (manufactured by Nippon Steel & Sumikin Chemical Co., Ltd., product name "FX293", Tg: approx. 160°C, Mw: approx. 40,000)

[0139] (b) Component: Thermosetting resin Triphenolmethane-containing multifunctional solid epoxy (manufactured by Mitsubishi Chemical Corporation, product name "EP1032H60") Bisphenol F liquid epoxy (manufactured by Mitsubishi Chemical Corporation, product name "YL983U")

[0140] (c) Component: Hardener 2,4-Diamino-6-[2'-methylimidazolyl-(1')]-ethyl-s-triazine isocyanuric acid adduct (manufactured by Shikoku Chemicals Corporation, trade name "2MAOK-PW", Mw: 384)

[0141] (d) Component: Flux compound α-Ketoglutaric acid (Fujifilm Wako Pure Chemical Industries, Ltd., melting point: 118°C, Mw: 146) Glutaric acid (Fujifilm Wako Pure Chemical Industries, Ltd., melting point: 98°C, Mw: 132) Benzilic acid (Fujifilm Wako Pure Chemical Industries, Ltd., melting point: 152°C, Mw: 228)

[0142] (e) Filler Silica filler (manufactured by Admatechs Co., Ltd., product name "SE2030", average particle size 0.5 μm) Epoxy silane surface-treated silica filler (manufactured by Admatechs Co., Ltd., product name "SE2030-SEJ", average particle size 0.5 μm) Methacrylic surface-treated silica filler (manufactured by Admatechs Co., Ltd., product name "YA050C-SM1", average particle size approximately 0.05 μm)

[0143] The weight average molecular weight (Mw) of the component (a) was determined by the GPC method, the details of which are as follows. Device name: HPLC-8020 (product name, manufactured by Tosoh Corporation) Column: 2 pieces of GMHXL + 1 piece of G-2000XL Detector: RI detector Column temperature: 35℃ Flow rate: 1mL / min Standard material: polystyrene

[0144] <Preparation of film-type adhesive for semiconductors> The thermoplastic resin, thermosetting resin, curing agent, flux compound, and filler in the amounts (unit: parts by mass) shown in Table 1 were added to an organic solvent (cyclohexanone) so that the NV value ([mass of paint after drying] / [mass of paint before drying] × 100) was 50%. Then, 1.0 mm diameter zirconia beads and 2.0 mm diameter zirconia beads in the same mass as the solids (thermoplastic resin, thermosetting resin, curing agent, flux compound, and filler) were added to the same container and mixed for 30 minutes in a ball mill (Fritsch Japan Co., Ltd., planetary mill P-7). After mixing, the zirconia beads were removed by filtration to prepare the coating varnish.

[0145] The obtained coating varnish was applied onto a base film (manufactured by Teijin DuPont Films Limited, trade name "Purellex A55") using a small precision coating apparatus (manufactured by Yasui Seiki Co., Ltd.), and dried in a clean oven (manufactured by ESPEC) at 100 °C for 10 minutes to obtain a film-shaped adhesive with a film thickness of 20 μm.

[0146] The evaluation methods for the film-shaped adhesives obtained in the examples and comparative examples are shown below. The evaluation results are shown in Table 1.

[0147] <DSC Measurement> [[ID=##]]10 mg of the obtained film-shaped adhesive was weighed into an aluminum pan (manufactured by Epolid Service Co., Ltd.), covered with an aluminum lid, and the evaluation sample was sealed in the sample pan using a crimper. Using a differential scanning calorimeter (Thermo plus DSC8235E, manufactured by Rigaku Corporation), measurements were taken under a nitrogen atmosphere at a heating rate of 10 °C / min and a measurement temperature range of 30 to 300 °C. As the analysis method for the heat generation amount, the partial area analysis method was used. By specifying the analysis in the temperature range of 60 to 280 °C for each DSC curve, the baseline of the analysis temperature range was specified and the integral of the peak area was performed to calculate the total heat generation amount (unit: J / g). Subsequently, by specifying 155 °C as the split temperature, the partial areas of 60 to 155 °C and 155 to 280 °C were integrated respectively to calculate each heat generation amount (unit: J / g). On the other hand, as the analysis method for the onset temperature, the full area (JIS method) analysis technique was used. By specifying the analysis in the temperature range of 60 to 280 °C, the intersection point of the baseline of the peak in each DSC curve and the maximum slope point was calculated to obtain the onset temperature (unit: °C).

[0148] <High Temperature Stability Evaluation> The film-shaped adhesives (initial samples) obtained in the examples and comparative examples were placed in an oven set at 80 °C, and after heat treatment for 6 hours, the samples were taken out to obtain evaluation samples A after heat treatment at 80 °C.

[0149] The film adhesives (initial samples) obtained in the examples and comparative examples were placed in an oven set at 100°C and heat-treated for 1 hour, after which the samples were removed to obtain evaluation sample B after heat treatment at 100°C.

[0150] Using evaluation sample A and evaluation sample B, the calorific value (unit: J / g) from 60 to 250°C was calculated using a differential scanning calorimeter (Thermo plus DSC8235E, manufactured by Rigaku Corporation) in the same manner as before the heat treatment. This was defined as the calorific value after the heat treatment.

[0151] The reaction rate was calculated using the two obtained heat release values ​​(heat release value of the initial sample and heat release value of evaluation sample A, or heat release value of the initial sample and heat release value of evaluation sample B) according to the following formula. Reaction rate (%) = (initial heat generation amount - heat generation amount after heat treatment) / initial heat generation amount x 100 A response rate of less than 5% was rated as "A," a response rate of 5% or more but less than 10% was rated as "B," and a response rate of 10% or more was rated as "C."

[0152] <Viscosity measurement> Using the film-like adhesives (initial samples) obtained in the Examples and Comparative Examples, a desktop laminator (product name: Hotdog GK-13DX, manufactured by Lamy Corporation) was used to laminate the film-like adhesives multiple times until they reached 400 μm, thereby preparing samples for viscosity measurement. The lamination conditions were a device set temperature of 50°C and a device conveying speed level of 9.

[0153] The laminated viscosity measurement samples were punched out using a 10 mm square punch, and the initial samples and evaluation sample A of the examples and comparative examples were used to measure the melt viscosity at 80°C (80°C viscosity), the melt viscosity at 130°C (130°C viscosity), the minimum melt viscosity, and the temperature showing the minimum melt viscosity (melting temperature) using a rotational rheometer (manufactured by TA Instruments, product name: ARES-G2). [Measurement conditions] Measuring tool size: 9mmφ Sample thickness: 400 μm Heating rate: 10°C / min Frequency: 10Hz Temperature range: 30~170℃

[0154] <Void evaluation> (Production of laminate C (temporarily fixed body C) after temporary pressure bonding) The film adhesive (initial sample) obtained in the above examples and comparative examples was thinned to a film thickness of 40 μm using a desktop laminator (product name: Hotdog GK-13DX, manufactured by Lamy Corporation), and then cut into 7.5 mm square pieces. These were then attached to semiconductor chips with multiple solder bumps (chip size: 7.3 mm x 7.3 mm, thickness: 0.1 mm, bump (connection part) height: approximately 45 μm (total of copper pillar and solder), number of bumps: 1048 pins, pitch: 80 μm, product name: WALTS-TEG CC80, manufactured by Waltz Corporation) at 80°C. The semiconductor chip with the film-like adhesive attached was successively pressure-bonded and temporarily fixed to another semiconductor chip (chip size: 10 mm × 10 mm, thickness: 0.1 mm, number of bumps: 1048 pins, pitch: 80 μm, product name: WALTS-TEG IP80, manufactured by Waltz Corporation) by applying heat and pressure using a flip chip bonder (FCB3, manufactured by Panasonic Corporation), to obtain a temporarily pressure-bonded laminate C (temporarily fixed body C). The pressure-bonding conditions were 130°C, 75 N, and 3 seconds.

[0155] The laminate (temporary fixed body C) after the above pre-press bonding was placed in an oven set at 80°C and heated for 6 hours, after which the sample was removed to obtain laminate D (temporary fixed body D) after pre-press bonding after heat treatment at 80°C.

[0156] The laminate D (temporarily fixed body D) after the temporary pressure bonding was placed in the oven of a pressure oven device (manufactured by NTT Advanced Technology Corporation). The pressure inside the oven was set to 0.8 MPa, and the temperature was increased from room temperature to 190°C at a rate of 20°C / min. Next, while maintaining the pressure and temperature, the bonded body was heated in a pressurized atmosphere for 1 hour, and a mounting sample E for evaluation was obtained.

[0157] (Analysis and evaluation) An external image of the mounting sample for evaluation was taken using an ultrasound imaging diagnostic device (product name: Insight-300, manufactured by Insight Corporation). [Measurement conditions] Probe frequency: 180MHz Diagnostic mode: Echo (pulse-echo method)

[0158] From the obtained images, an image of the adhesive layer between the chips was scanned using a scanner (GT-9300UF, manufactured by Seiko Epson Corporation). In the scanned images, voids were identified by color correction and two-tone gradation using image processing software (Adobe Photoshop (trade name)), and the percentage of voids was calculated using a histogram. The area of ​​the entire adhesive layer, including voids, was taken as 100%. When the void area percentage was less than 10%, it was rated as "A," when the void area percentage was 10% or more but less than 30%, it was rated as "B," and when it was 30% or more, it was rated as "C." The evaluation results are shown in Table 1.

[0159] <Check for cracks in the connection area> (Production of laminate F (temporarily fixed body F) after temporary pressure bonding) The film adhesive (initial sample) obtained in the above examples and comparative examples was thinned to a film thickness of 40 μm using a desktop laminator (product name: Hotdog GK-13DX, manufactured by Lamy Corporation), and then cut into 7.5 mm square pieces. These were then attached to semiconductor chips with multiple solder bumps (chip size: 7.3 mm x 7.3 mm, thickness: 0.1 mm, bump (connection part) height: approximately 45 μm (total of copper pillar and solder), number of bumps: 1048 pins, pitch: 80 μm, product name: WALTS-TEG CC80, manufactured by Waltz Corporation) at 80°C. The semiconductor chip with the film adhesive attached was successively bonded and temporarily fixed to another semiconductor chip (chip size: 10 mm x 10 mm, thickness: 0.1 mm, number of bumps: 1048 pins, pitch: 80 μm, product name: WALTS-TEG IP80, manufactured by Waltz Corporation) by heating and pressurizing using a flip chip bonder (FCB3, manufactured by Panasonic Corporation), to obtain a temporarily bonded laminate F (temporarily fixed body F). The bonding conditions were 190 ° C / 25 N / 10 seconds, 260 ° C / 25 N / 20 seconds, and 100 ° C / 25 N / 5 seconds (set temperature rise time for each temperature rise: 0.1 seconds).

[0160] The laminate F (temporarily fixed body F) after the temporary pressure bonding was placed in the oven of a pressure oven device (manufactured by NTT Advanced Technology Corporation). The pressure inside the oven was set to 0.8 MPa, and the temperature was increased from room temperature to 190°C at a rate of 20°C / min. Next, while maintaining the pressure and temperature, the bonded body was heated in a pressurized atmosphere for 1 hour, and a mounting sample G for evaluation was obtained.

[0161] The above evaluation mounted sample was polished using a tabletop polisher (Refine Polisher, Refine Tech Co., Ltd.) until the bump connections inside the chip were exposed. The waterproof abrasive paper used for polishing was initially 200 cm diameter and 1000 grit, then replaced with waterproof abrasive paper with 2000 grit, and polished until the connections were exposed. Further polishing was then performed using alumina liquid (hanging liquid) A-0.3 micron (Refine Tech Co., Ltd.). The exposed bump connections were observed using a SEM (TM3030Plus tabletop microscope, Hitachi High-Technologies Corporation) to check for cracks inside the solder and at the solder-Cu wiring interface.

[0162] <Connectivity evaluation> The resulting evaluation sample G was evaluated for connectivity by measuring the resistance of the chip's inner periphery using a circuit tester (POCKET TESTER 4300 COUNT, manufactured by CUSTOM). Figure 4 shows the circuit diagram of the lower chip used for mounting (chip size: 7.3 mm x 7.3 mm, thickness: 0.1 mm, bump (connection) height: approximately 45 μm (total of copper pillars and solder), number of bumps: 1048 pins, pitch: 80 μm, product name: WALTS-TEG CC80, manufactured by Waltz Corporation). In this circuit, the resistance between terminals a and b in the diagram represents the resistance of the chip's inner periphery. A resistance value of less than 35 Ω indicates good connectivity, while a resistance value of 35 Ω or greater or an unmeasurable resistance value indicates poor connectivity.

[0163] <Evaluation of solder wettability> For the above evaluation mounting samples, the cross section of the connection was observed using an SEM in the same way as for checking for cracks in the connection, and the results were rated as "A" (good) if 90% or more of the solder was wetted on the top surface of the Cu wiring, and "B" (insufficient wetness) if the solder was wetted less than 90%.

[0164] [Table 1] [Explanation of symbols]

[0165] 1...semiconductor chip, 2...substrate, 10...semiconductor chip body, 15, 16...wiring or bumps, 20...substrate body, 30...solder, 34...through electrode, 40...adhesive layer, 50...interposer body, 100, 300, 500...semiconductor device.

Claims

1. An adhesive for semiconductors comprising a thermoplastic resin, a thermosetting resin, a curing agent, a flux compound having at least one carboxyl group, and a filler, The flux compound has a structure in which at least one electron-withdrawing group is substituted on the α-position carbon of the carboxyl group.

2. The adhesive for semiconductors according to claim 1 , wherein the flux compound includes a compound having two carboxyl groups.

3. 3. The adhesive for semiconductors according to claim 1, wherein the flux compound comprises a compound represented by the following general formula (2-1) or (2-2): 【Chemical 1】 【Chemistry 2】 [In formulas (2-1) and (2-2), R １ represents an electron-withdrawing group, and R ２ represents a hydrogen atom or an electron-withdrawing group, and R ３ represents a hydrogen atom or a monovalent organic group, and n represents an integer of 0 to 15. ３ may be the same or different.

4. The adhesive for semiconductors according to any one of claims 1 to 3, wherein the flux compound comprises a compound represented by the following general formula (3-1) or (3-2): 【Chemistry 3】 【Chemistry 4】 [In formulas (3-1) and (3-2), R １ represents an electron-withdrawing group, and R ２ represents a hydrogen atom or an electron-withdrawing group, and R ３ represents a hydrogen atom or a monovalent organic group, and m represents an integer of 0 to 10.

5. 5. The adhesive for semiconductors according to claim 1, wherein the flux compound has a melting point of 170° C. or lower.

6. The adhesive for semiconductors according to any one of claims 1 to 5, wherein the thermosetting resin comprises an epoxy resin.

7. The adhesive for semiconductors according to any one of claims 1 to 6, wherein the curing agent includes an amine-based curing agent.

8. The adhesive for semiconductors according to any one of claims 1 to 7, wherein the curing agent comprises an imidazole-based curing agent.

9. The adhesive for semiconductors according to claim 8 , wherein the structure of the imidazole-based curing agent includes a triazine ring.

10. A semiconductor adhesive described in any one of claims 1 to 9, wherein the ratio of the number of moles of acid groups in the total amount of the flux compound to the number of moles of reactive groups in the total amount of the curing agent is 0.5 or more.

11. A method for manufacturing a semiconductor device in which connection portions of a semiconductor chip and a wiring circuit board are electrically connected to each other, or a semiconductor device in which connection portions of a plurality of semiconductor chips are electrically connected to each other, comprising: A method for manufacturing a semiconductor device, comprising a sealing step of curing a semiconductor adhesive described in any one of claims 1 to 10 by applying heat under a pressurized atmosphere, and sealing at least a portion of the connection portion with the cured semiconductor adhesive.

12. Before the sealing step, placing a plurality of semiconductor chips on a stage; 12. The method for manufacturing a semiconductor device according to claim 11, further comprising a temporary fixing process in which, while heating the stage to 60 to 155°C, other semiconductor chips are sequentially placed on top of each of the plurality of semiconductor chips placed on the stage via the semiconductor adhesive, thereby obtaining a plurality of stacks in which the semiconductor chips, the semiconductor adhesive, and the other semiconductor chips are stacked in this order.

13. Before the sealing step, placing a printed circuit board or a semiconductor wafer on a stage; 12. The method for manufacturing a semiconductor device according to claim 11, further comprising a temporary fixing process in which, while heating the stage to 60 to 155°C, a plurality of semiconductor chips are sequentially placed on the wiring circuit board or semiconductor wafer placed on the stage via the semiconductor adhesive, to obtain a laminate in which the wiring circuit board, the semiconductor adhesive, and a plurality of the semiconductor chips are stacked in this order, or a laminate in which the semiconductor wafer, the semiconductor adhesive, and a plurality of the semiconductor chips are stacked in this order.

14. A semiconductor device in which the connection portions of a semiconductor chip and a wiring circuit board are electrically connected to each other, or a semiconductor device in which the connection portions of multiple semiconductor chips are electrically connected to each other, wherein at least a portion of the connection portions is sealed with a cured product of the semiconductor adhesive according to any one of claims 1 to 10, which has been cured by applying heat under a pressurized atmosphere.

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