Adhesive for semiconductor, and semiconductor device

Abstract

To reduce voids that remain in adhesive for a semiconductor in a process which temporarily fixes a plurality of semiconductor chips on a target member via adhesive for a semiconductor and collectively performs curing and sealing.SOLUTION: An adhesive for a semiconductor containing a thermoplastic resin, a thermosetting resin, a curing agent having a reactive group, and a flux compound having an acid group, where a heat value Q1 at 60 to 155°C on a DSC curve obtained by differential scanning calorimetry when the adhesive for a semiconductor is heated at a temperature rising rate of 10°C / min is 20 J / g or less.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to an adhesive for semiconductors and a method for manufacturing the same, 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, which form connection parts (bumps or wiring) on ​​semiconductor chips to connect between semiconductor chips, and COW (Chip On Wafer) type connection methods, which form connection parts (bumps or wiring) on ​​semiconductor wafers to connect between semiconductor chips and semiconductor wafers (see, for example, Patent Document 1).

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

[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 way to prevent the generation of these impurities is to coat the connection area with an anti-oxidation film, known as an 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 cured all at once by reflow at a temperature above the melting point of the connection (for example, approximately 260°C). This process allows multiple semiconductor 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 aspect of the present invention reduces voids that may remain in a semiconductor adhesive in a process in which multiple semiconductor chips are temporarily fixed onto a mounting member via a semiconductor adhesive and then cured and sealed all at once. [Means for solving the problem]

[0013] The inventors of the present invention have speculated that when a large number of semiconductor chips are mounted in the above process, the semiconductor adhesive partially hardens during temporary fixation, resulting in voids remaining in the semiconductor adhesive. In other words, since 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 speculated that when the number of semiconductor chips is large, the semiconductor adhesive temporarily fixing the initially mounted semiconductor chips partially hardens, resulting in voids remaining without being removed by the pressure applied during the bulk hardening. Based on this speculation, the inventors of the present invention conducted further studies and completed the present invention.

[0014] Some aspects of the present invention provide the following.

[0015] [1] A semiconductor adhesive comprising a thermoplastic resin, a thermosetting resin, a curing agent having a reactive group, and a flux compound having an acid group, wherein the heat generation value between 60 and 155°C in a DSC curve obtained by differential scanning calorimetry in which the semiconductor adhesive is heated at a temperature increase rate of 10°C / min is 20 J / g or less.

[0016] [2] The adhesive for semiconductors according to [1], wherein the weight average molecular weight (Mw) of the thermoplastic resin is 10,000 or more.

[0017] [3] The adhesive for semiconductors according to [1] or [2], wherein the content of the thermoplastic resin is 1 to 30 mass % based on the total solid content of the adhesive for semiconductors.

[0018] [4] The adhesive for semiconductors according to any one of [1] to [3], wherein the content of the thermoplastic resin is 5 mass % or more based on the total solid content of the adhesive for semiconductors.

[0019] [5] The adhesive for a semiconductor according to any one of [1] to [4], wherein the curing agent includes an amine-based curing agent.

[0020] [6] The adhesive for a semiconductor according to any one of [1] to [5], wherein the curing agent includes an imidazole-based curing agent.

[0021] [7] The adhesive for semiconductors according to any one of [1] to [6], wherein the content of the curing agent is 2.3 mass % or less based on the total solid content of the adhesive for semiconductors.

[0022] [8] The adhesive for a semiconductor according to any one of [1] to [7], wherein the melting point of the flux compound is 25 to 230°C.

[0023] [9] The adhesive for a semiconductor according to any one of [1] to [8], wherein the melting point of the flux compound is 100 to 170°C.

[0024]

[10] The adhesive for a semiconductor according to any one of [1] to [9], wherein the thermosetting resin contains an epoxy resin.

[0025]

[11] The adhesive for a semiconductor according to any one of [1] to

[10] , wherein the thermosetting resin does not substantially contain an epoxy resin that is liquid at 35°C.

[0026]

[12] The adhesive for semiconductors according to any one of [1] to

[11] , which is in the form of a film.

[0027]

[13] The adhesive for a semiconductor according to any one of [1] to

[12] , which is cured by applying heat under a pressurized atmosphere. This adhesive for a semiconductor may be cured by applying heat under a pressurized atmosphere, and used to seal connections of a semiconductor chip with the cured adhesive for a semiconductor.

[0028]

[14] The adhesive for semiconductors according to any one of [1] to

[13] , wherein the adhesive for semiconductors has a minimum melt viscosity of 400 to 2500 Pa·s.

[0029]

[15] A semiconductor adhesive described in any one of [1] to

[14] , wherein the ratio of the number of moles of the acid groups in the total amount of the flux compound to the number of moles of the reactive groups in the total amount of the curing agent is 0.01 to 4.8.

[0030]

[16] A method for manufacturing an adhesive for semiconductors, comprising a step of mixing a thermoplastic resin, a thermosetting resin, a curing agent having a reactive group, and a flux compound having an acid group, wherein in the step, the curing agent and the flux compound are blended so that the ratio of the number of moles of the acid groups in the total amount of the flux compound to the number of moles of the reactive groups in the total amount of the curing agent is 0.01 to 4.8.

[0031]

[17] The flux compound includes at least one selected from the group consisting of monocarboxylic acids, dicarboxylic acids, and tricarboxylic acids;

[16] A method for producing a semiconductor adhesive, wherein in the process, the curing agent and the flux compound are blended so that the ratio of the number of moles of the monocarboxylic acid to the number of moles of reactive groups in the total amount of the curing agent is 0.01 to 4.8, the ratio of the number of moles of the dicarboxylic acid to the number of moles of reactive groups in the total amount of the curing agent is 0.01 to 2.4, and the ratio of the number of moles of the tricarboxylic acid to the number of moles of reactive groups in the total amount of the curing agent is 0.01 to 1.6.

[0032]

[18] A method for producing an adhesive for semiconductors according to

[16] or

[17] , wherein the weight average molecular weight (Mw) of the thermoplastic resin is 10,000 or more.

[0033]

[19] A method for producing a semiconductor adhesive according to any one of

[16] to

[18] , wherein the blending amount of the thermoplastic resin is 1 to 30 mass % based on the total solid content of the semiconductor adhesive.

[0034]

[20] A method for producing an adhesive for semiconductors according to any one of

[16] to

[19] , wherein the amount of the thermoplastic resin is 5 mass% or more based on the total solid content of the adhesive for semiconductors.

[0035]

[21] The method for producing an adhesive for a semiconductor according to any one of

[16] to

[20] , wherein the curing agent includes an amine-based curing agent.

[0036]

[22] A method for producing an adhesive for a semiconductor according to any one of

[16] to

[21] , wherein the curing agent includes an imidazole-based curing agent.

[0037]

[23] A method for producing a semiconductor adhesive according to any one of

[16] to

[22] , wherein the amount of the curing agent is 2.3 mass % or less based on the total solid content of the semiconductor adhesive.

[0038]

[24] The method for producing an adhesive for a semiconductor according to any one of

[16] to

[23] , wherein the melting point of the flux compound is 25 to 230°C.

[0039]

[25] The method for producing an adhesive for a semiconductor according to any one of

[16] to

[24] , wherein the melting point of the flux compound is 100 to 170°C.

[0040]

[26] A method for producing an adhesive for a semiconductor according to any one of

[16] to

[25] , wherein the thermosetting resin contains an epoxy resin.

[0041]

[27] The method for producing an adhesive for a semiconductor according to any one of

[16] to

[26] , wherein the thermosetting resin does not substantially contain an epoxy resin that is liquid at 35°C.

[0042]

[28] A method for manufacturing a semiconductor adhesive described in any of

[16] to

[27] , further comprising a step of molding a mixture containing the thermoplastic resin, the thermosetting resin, the curing agent, and the flux compound into a film.

[0043]

[29] A method for manufacturing 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 method for manufacturing a semiconductor device in which the connection portions of a plurality of semiconductor chips are electrically connected to each other, the method comprising a sealing step of applying heat to cure the adhesive for a semiconductor according to any one of [1] to

[15] , and sealing at least a part of the connection portions with the cured adhesive for a semiconductor. The adhesive for a semiconductor may be cured by applying heat under a pressurized atmosphere.

[0044]

[30] The method for manufacturing a semiconductor device described in

[29] further includes the steps of: before the sealing step, arranging a plurality of semiconductor chips on a stage; and, while heating the stage to 60 to 155°C, sequentially arranging other semiconductor chips on top of each of the plurality of semiconductor chips arranged on the stage via the semiconductor adhesive, thereby obtaining a plurality of stacks each having the semiconductor chip, the semiconductor adhesive, and the other semiconductor chip, stacked in this order.

[0045]

[31] The method for manufacturing a semiconductor device described in

[29] further comprises the steps of: before the sealing step, placing a wiring circuit board or a semiconductor wafer on a stage; and, while heating the stage to 60 to 155°C, sequentially placing multiple semiconductor chips on the wiring circuit board or semiconductor wafer placed on the stage via the semiconductor adhesive, thereby obtaining a laminate having the wiring circuit board, the semiconductor adhesive, and multiple semiconductor chips stacked in this order, or a laminate having the semiconductor wafer, the semiconductor adhesive, and multiple semiconductor chips stacked in this order.

[0046]

[32] A semiconductor device comprising a semiconductor chip having a connecting portion and a wiring circuit board having a connecting portion, wherein the connecting portion of the semiconductor chip and the connecting portion of the wiring circuit board are electrically connected to each other, or a semiconductor device comprising a plurality of semiconductor chips having connecting portions, wherein the connecting portions of the respective semiconductor chips are electrically connected to each other, wherein at least a portion of the connecting portion is sealed with a cured product of the adhesive for semiconductor according to any one of [1] to

[15] that has been cured by applying heat under a pressurized atmosphere. In other words, this semiconductor device is a semiconductor device in which the connecting portions of the semiconductor chip and the wiring circuit board are electrically connected to each other, or a semiconductor device in which the connecting portions of a plurality of semiconductor chips are electrically connected to each other. [Effects of the Invention]

[0047] According to one aspect of the present invention, in 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, it is possible to reduce voids that may remain in the semiconductor adhesive. According to another aspect of the present invention, it is possible to provide a semiconductor adhesive that can reduce such voids, a method for manufacturing the same, and a semiconductor device in which such voids are reduced, and a method for manufacturing the same. [Brief explanation of the drawings]

[0048] [Figure 1] FIG. 1 is a schematic diagram showing a method for determining the onset temperature of an exothermic peak from a DSC curve. [Figure 2] FIG. 1 is a schematic diagram showing a method for determining the calorific value between 60 and 155° C. from a DSC curve. [Figure 3] FIG. 1 is a schematic diagram showing a method for determining the calorific value between 60 and 155° C. from a DSC curve. [Figure 4] 1 is a schematic cross-sectional view showing an embodiment of a semiconductor device; [Figure 5] 1 is a schematic cross-sectional view showing an embodiment of a semiconductor device; [Figure 6] 1 is a schematic cross-sectional view showing an embodiment of a semiconductor device; [Figure 7]1A to 1C are schematic cross-sectional views showing an embodiment of a method for manufacturing a semiconductor device. DETAILED DESCRIPTION OF THE INVENTION

[0049] An embodiment of the present invention will be described in detail below, with reference to the drawings where necessary. 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.

[0050] 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.

[0051] <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 having a reactive group (hereinafter sometimes referred to as "component (c)"), and a flux compound having an acid 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.

[0052] 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 is 20 J / g or less. Here, the differential scanning calorimetry is performed by heating the semiconductor adhesive in an air or nitrogen atmosphere with a sample weight of 10 mg, a measurement temperature range of 30 to 300°C, and a heating rate of 10°C / min. The heat generation value is calculated by integrating the peak area.

[0053] 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 thermosetting resin and the flux compound in the semiconductor adhesive react during temporary fixing of the semiconductor chips, causing the adhesive to partially cure, preventing it from flowing sufficiently during bulk curing under pressure. The semiconductor adhesive of this embodiment has a calorific value of 20 J / g or less between 60 and 155°C on the DSC curve, and therefore does not cure easily in the temperature range (e.g., 60 to 155°C) where the semiconductor chips are temporarily fixed. Therefore, by using the semiconductor adhesive of this embodiment 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 (e.g., 260°C) during the reflow process. In other words, the semiconductor adhesive of this embodiment tends to improve reflow reliability (reflow resistance) in the manufacture of semiconductor devices.

[0054] The calorific value in the range of 60 to 155°C in the DSC curve may be 15 J / g or less, or 10 J / g or less, from the viewpoint of easily achieving the effects of the present invention. The calorific value in the range of 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 of 60 to 280°C, from the viewpoint of easily achieving the effects of the present invention. The calorific value in the range of 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, or 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. The DSC curve may not have an exothermic peak with an onset temperature of 155°C or less, from the viewpoint of easily achieving the effects of the present invention.

[0055] Fig. 1 is a schematic diagram showing a method for determining the onset temperature of an exothermic peak from a DSC curve. The DSC curve shown in Fig. 1 includes a baseline L0 in the temperature range of 60 to 280°C and an exothermic peak P due to the curing reaction of the adhesive, which is observed partway along the baseline L0. The onset temperature is the temperature T at the intersection of an extension line L1 of the baseline L0 below the exothermic peak P and a tangent line L2 to the DSC curve at the point where the DSC curve shows the maximum gradient at the exothermic peak P.

[0056] 2 and 3 are schematic diagrams showing a method for determining the calorific value between 60 and 155°C from a DSC curve. As shown in FIG. 2, when a DSC curve contains only an exothermic peak P including a portion at or below 155°C as an exothermic peak, the calorific value Q1 of the portion of exothermic peak P at or below 155°C is the calorific value between 60 and 155°C. The calorific value Q1 is determined from the area of ​​the region below 155°C enclosed by exothermic peak P and an extension line L1 of baseline L0. As shown in FIG. 3, when a DSC curve further contains a peak other than exothermic peak P in the region below 155°C, the sum of the calorific value Q2 of that peak and the calorific value Q1 of exothermic peak P at or below 155°C is the calorific value between 60 and 155°C. When more exothermic peaks are observed in the region below 60 and 155°C, the sum of the calorific values ​​of those exothermic peaks is the calorific value between 60 and 155°C.

[0057] 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 moles of acid groups in the total flux compound to the 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 includes a step of mixing a thermoplastic resin, a thermosetting resin, a curing agent having reactive groups, and a flux compound having acid groups, in which the curing agent and the flux compound are blended so that the ratio of the moles of acid groups in the total flux compound to the moles of reactive groups in the total curing agent is 0.01 to 4.8. In the semiconductor adhesive obtained by this method, the ratio of the moles of acid groups in the total flux compound to the moles of reactive groups in the total curing agent is typically 0.01 to 4.8. However, some of the reactive groups in the curing agent and some of the acid groups in the flux compound may form salts. The ratio of the number of moles including the number of reactive groups and acid groups forming the salt may be within the above range.

[0058] 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.

[0059] Hereinafter, each component constituting the adhesive for semiconductor use of this embodiment will be described.

[0060] (a) Thermoplastic resin 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, the thermoplastic resin may be selected from phenoxy resin, polyimide resin, acrylic resin, acrylic rubber, cyanate ester resin, and polycarbodiimide resin, or may be selected from phenoxy resin, polyimide resin, and acrylic resin. These components (a) can be used alone, or can be used as a mixture or copolymer of two or more types.

[0061] The weight-average molecular weight (Mw) of component (a) may be 10,000 or more, 40,000 or more, or 60,000 or more. Such component (a) can further improve the film-formability and heat resistance of the adhesive. A weight-average molecular weight of 10,000 or more easily imparts flexibility to the film-shaped semiconductor adhesive, making it easier to achieve even better processability. The weight-average molecular weight of component (a) may be 1,000,000 or less, or 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 perspectives, the weight-average molecular weight of component (a) may be 10,000 to 1,000,000, 40,000 to 500,000, or 60,000 to 500,000.

[0062] 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

[0063] (a) Component content C a (b) component content C b Ratio of C b / C a The ratio C (mass ratio) may be 0.01 or more, 0.1 or more, or 1 or more, and may be 5 or less, 4.5 or less, or 4 or less. b / C a By making the ratio C 0.01 or more, better curing properties and adhesive strength can be obtained. b / C a By setting the ratio C to 5 or less, better film formability can be obtained. b / C a may be 0.01 to 5, 0.1 to 4.5, or 1 to 4.

[0064] From the viewpoint of improving connection reliability, etc., the glass transition temperature of component (a) may be -50°C or higher, -40°C or higher, or -30°C or higher. From the viewpoint of lamination, etc., the glass transition temperature of component (a) may be 220°C or lower, 200°C or lower, or 180°C or lower. The glass transition temperature of component (a) may be -50 to 220°C, -40 to 200°C, or -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).

[0065] The content of component (a) may be 30% by mass or less, 25% by mass or less, or 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 in a temperature cycle test and can achieve good adhesive strength at a reflow temperature of around 260°C even after moisture absorption. The content of component (a) may be 1% by mass or more, 3% by mass or more, or 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 a wafer-level mounting process 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 viewpoint, and from the viewpoint of easily imparting flexibility to a film-shaped semiconductor adhesive and easily achieving even better processability, the content of component (a) may be 1 to 30 mass%, 3 to 30 mass%, or 5 to 30 mass%, based on the total solid content of the semiconductor adhesive. The "total solid content of the semiconductor adhesive" refers to the amount obtained by subtracting the amount of solvent contained in the semiconductor adhesive from the total amount of the semiconductor adhesive. In this specification, the "total solid content of the semiconductor adhesive" may also be rephrased as "the total amount of components (a), (b), (c), (d), and (e)."

[0066] (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.

[0067] Examples of component (b) include epoxy resins, phenolic resins, imide resins, urea resins, melamine resins, silicone resins, (meth)acrylic compounds, and vinyl compounds. From the viewpoint of excellent heat resistance (reflow resistance) and storage stability, the thermosetting resin may be selected from epoxy resins, phenolic resins, and imide resins, or may be selected from epoxy resins and imide resins, or may be an epoxy resin. 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 in the temperature range of 60 to 155°C, resulting in partial curing before overall curing. However, in this 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.

[0068] Examples of epoxy resins and imide resins 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.

[0069] In order to prevent the (b) component from decomposing and generating volatile components when connected at high temperatures, the component may have a thermal weight loss rate of 5% or less at 250°C when the temperature at the time of connection is 250°C, and may have a thermal weight loss rate of 5% or less at 300°C when the temperature at the time of connection is 300°C.

[0070] Component (b) may be substantially free of an epoxy resin that is liquid at 35°C. For example, the content of the epoxy resin that is liquid at 35°C may be 0.1 parts 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 obtain semiconductor packages with even better throughput.

[0071] The content of component (b) may be, for example, 5% by mass or more, 15% by mass or more, or 30% by mass or more, based on the total solid content of the adhesive for semiconductors. The content of component (b) may be, for example, 80% by mass or less, 70% by mass or less, or 60% by mass or less, based on the total solid content of the adhesive for semiconductors. The content of component (b) may be, for example, 5 to 80% by mass, 15 to 70% by mass, or 30 to 60% by mass, based on the total solid content of the adhesive for semiconductors.

[0072] (c) Hardener Component (c) is a compound that reacts with the reactive group of the thermosetting resin or accelerates the curing reaction of the thermosetting resin. It may be a compound having a reactive group capable of forming a salt with the fluxing agent described below. Examples of component (c) include amine-based curing agents, which are compounds having an amino group as a reactive group, and imidazole-based curing agents, which are compounds having an imidazole group as a reactive group. 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. When component (c) contains an amine-based or imidazole-based curing agent, it further improves storage stability and tends to be less susceptible to decomposition or degradation due to moisture absorption. When component (c) contains an amine-based or imidazole-based curing agent, it becomes easier to adjust the curing speed, and its fast curing property facilitates the realization of short-time connections for the purpose of improving productivity.

[0073] Each curing agent will be described below.

[0074] (i) Amine-based curing agents As the amine-based curing agent, for example, dicyandiamide can be used.

[0075] The content of the amine-based curing agent may be 0.1 parts by mass or more, 10 parts by mass or less, or 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 be improved. When the content of the amine-based curing agent 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 may be 0.1 to 10 parts by mass, or 0.1 to 5 parts by mass, per 100 parts by mass of the component (b).

[0076] (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. From the viewpoint of excellent curing property, storage stability and connection reliability, imidazole curing agents are 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 ... The latent curing agent may be selected from the group consisting of 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. These may be used alone or in combination. Microcapsules containing these may be used as the latent curing agent.

[0077] The content of the imidazole-based curing agent may be 0.1 parts by mass or more, 10 parts by mass or less, 5 parts by mass or less, or 2.3 parts by mass or less, per 100 parts by mass of component (b). When the content of the imidazole-based curing agent is 0.1 parts by mass or more, curability tends to be improved. When the content of the imidazole-based curing agent is 10 parts by mass or less, the semiconductor adhesive does not harden before a metal bond is formed, connection failure is less likely to occur, and the occurrence of voids in a curing process under a pressurized atmosphere is easily suppressed. From these viewpoints, the content of the imidazole-based curing agent may be 0.1 to 10 parts by mass, 0.1 to 5 parts by mass, or 0.1 to 2.3 parts by mass, per 100 parts by mass of component (b).

[0078] 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).

[0079] The content of component (c) may be 0.5 parts by mass or more, 20 parts by mass or less, 6 parts by mass or less, or 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 rapidly, preventing an increase in the number of reaction sites, and tends to prevent a decrease in reliability due to shortened molecular chains or remaining unreacted groups. In addition, it tends to prevent the formation of voids during curing under a pressurized atmosphere. From these perspectives, the content of component (c) may be 0.2 to 20 parts by mass, 0.5 to 6 parts by mass, or 0.5 to 4 parts by mass, per 100 parts by mass of component (b).

[0080] The content of component (c) may be 0.5% by mass or more, 2.3% by mass or less, 2.0% by mass or less, or 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 progression and an increase in the number of reaction sites tends to be suppressed, and a decrease in reliability due to shortened molecular chains or remaining unreacted groups tends to be prevented. In addition, the remaining of voids during curing under a pressurized atmosphere tends to be suppressed. From these perspectives, the content of component (c) may be 0.5 to 2.3% by mass or 0.5 to 2.0% by mass, based on the total solid content of the semiconductor adhesive.

[0081] When the adhesive for semiconductors contains an amine-based curing agent as component (c), it exhibits flux activity that removes oxide films, and can further improve connection reliability.

[0082] (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.

[0083] Component (d) has one or more acid groups. The acid group is, for example, a carboxyl group. When component (d) is a compound having a carboxyl group (for example, a carboxylic acid), even better connection reliability is likely to be obtained. When component (d) is a compound having a carboxyl group (for example, a carboxylic acid), from the viewpoint of making it easier to obtain the effects of the present invention, component (b) may be at least one thermosetting resin selected from the group consisting of epoxy resins, urethane resins, and urea resins, and component (c) may be at least one curing agent selected from the group consisting of amine-based curing agents and imidazole-based curing agents.

[0084] Examples of compounds having a carboxyl group include compounds having a group represented by the following formula (1). [ka] In formula (1), R 1 represents a hydrogen atom or an electron-donating group.

[0085] Examples of the electron-donating group include an alkyl group, a hydroxyl group, an amino group, an alkoxy group, and an alkylamino group.

[0086] The alkyl group may be an alkyl group having 1 to 10 carbon atoms, or an alkyl group having 1 to 5 carbon atoms. When the number of carbon atoms in the alkyl group is within the above range, an excellent balance between electron donating property and steric hindrance is achieved.

[0087] The alkyl group may be linear or branched, or may be linear. When the alkyl group is linear, the number of carbon atoms in the alkyl group may be equal to or less than the number of carbon atoms in the main chain of the flux compound, from the viewpoint of the balance between electron donating property and steric hindrance.

[0088] The alkoxy group may be an alkoxy group having 1 to 10 carbon atoms, or an alkoxy group having 1 to 5 carbon atoms. When the number of carbon atoms in the alkoxy group is within the above range, an excellent balance between electron donating property and steric hindrance is achieved.

[0089] The alkyl group portion of the alkoxy group may be linear or branched, or may be linear. When the alkoxy group is linear, the number of carbon atoms in the alkoxy group may be equal to or less than the number of carbon atoms in the main chain of the flux compound, from the viewpoint of the balance between electron donating property and steric hindrance.

[0090] Examples of the alkylamino group include a monoalkylamino group and a dialkylamino group. The monoalkylamino group may be a monoalkylamino group having 1 to 10 carbon atoms, or a monoalkylamino group having 1 to 5 carbon atoms. The alkyl group portion of the monoalkylamino group may be linear or branched, or may be linear. The dialkylamino group may be a dialkylamino group having 2 to 20 carbon atoms, or a dialkylamino group having 2 to 10 carbon atoms. The alkyl group portion of the dialkylamino group may be linear or branched, or may be linear.

[0091] Component (d) may be a compound having 1 to 3 acid groups, or may be a compound having 1 to 3 carboxyl groups as the acid groups. Component (d) may include 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 semiconductor adhesive during storage, connection work, etc. can be further suppressed compared to when a compound having four or more carboxyl groups is used, and the connection reliability of the semiconductor device can be further improved.

[0092] Component (d) may contain a monocarboxylic acid. For example, when the thermosetting resin is an epoxy resin, urethane resin, or urea resin, a portion of component (b) reacts with a portion of component (d) to form an ester during thermal polymerization (curing). However, when a compound having one carboxyl group is used, the ester bond derived from this ester is unlikely to exist in the polymer main chain. Therefore, even if ester hydrolysis occurs due to moisture absorption, the molecular chain is not significantly reduced. Therefore, the adhesion strength (e.g., adhesion to silicon) after moisture absorption and the bulk strength of the cured product can be maintained at a high level, and the reflow resistance and connection reliability of the semiconductor device can be further improved.

[0093] The melting point of component (d) may be 25°C or higher, 90°C or higher, or 100°C or higher, or 230°C or lower, 180°C or lower, 170°C or lower, or 160°C or lower. When component (d) has a melting point of 230°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, with a semiconductor adhesive containing component (d), 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 component (d) has a melting point of 25°C or higher, reaction at room temperature is less likely to initiate, resulting in even more excellent storage stability. From these perspectives, component (d) may have a melting point of 25 to 230°C, 90 to 180°C or lower, 100 to 170°C, or 100 to 160°C.

[0094] (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 sudden increase in temperature creates a temperature gradient between the sample and the thermometer, resulting in measurement errors, so it is desirable to increase the temperature at a rate of less than 1°C per minute when measuring the melting point.

[0095] As mentioned above, because the sample is prepared as a fine powder, it is opaque before melting due to diffuse reflection from the surface. The lower limit of the melting point is usually determined as the temperature at which the sample begins to become transparent, and the upper limit is determined as the temperature at which the sample is completely melted. While various types of measurement devices exist, the most classic is a double-tube thermometer with a capillary tube filled with the sample attached and heated in a hot bath. A highly viscous liquid, often concentrated sulfuric acid or silicone oil, is used as the hot bath liquid to attach the capillary tube to the double-tube thermometer, and the sample is attached so that it is near the reservoir at the tip of the thermometer. Melting point measurement devices can also be used that use a metal heat block to heat the sample, and automatically determine the melting point by adjusting the heating while measuring the light transmittance.

[0096] In this specification, a melting point of 230°C or lower means that the upper limit of the melting point is 230°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.

[0097] Specific examples of component (d) include malonic acid, methylmalonic acid, dimethylmalonic acid, ethylmalonic acid, allylmalonic acid, 2,2'-thiodiacetic acid, 3,3'-thiodipropionic acid, 2,2'-(ethylenedithio)diacetic acid, 3,3'-dithiodipropionic acid, 2-ethyl-2-hydroxybutyric acid, dithiodiglycolic acid, diglycolic acid, acetylenedicarboxylic acid, maleic acid, malic acid, 2-isopropylmalic acid, tartaric acid, itaconic acid, 1,3-acetonedicarboxylic acid, tricarbalilic acid, muconic acid, β-hydromuconic acid, succinic acid, and methylsuccinic acid. Citric acid, dimethylsuccinic acid, glutaric acid, α-ketoglutaric acid, 2-methylglutaric acid, 3-methylglutaric acid, 2,2-dimethylglutaric acid, 3,3-dimethylglutaric acid, 2,2-bis(hydroxymethyl)propionic acid, citric acid, adipic acid, 3-tert-butyladipic acid, pimelic acid, phenyloxalic acid, phenylacetic acid, nitrophenylacetic acid, phenoxyacetic acid, nitrophenoxyacetic acid, phenylthioacetic acid, hydroxyphenylacetic acid, dihydroxyphenylacetic acid, mandelic acid, hydroxymandelic acid, dihydroxymandelic acid, 1,2,3 ,4-Butanetetracarboxylic acid, suberic acid, 4,4'-dithiodibutyric acid, cinnamic acid, nitrocinnamic acid, hydroxycinnamic acid, dihydroxycinnamic acid, coumaric acid, phenylpyruvic acid, hydroxyphenylpyruvic acid, caffeic acid, homophthalic acid, tolylacetic acid, phenoxypropionic acid, hydroxyphenylpropionic acid, benzyloxyacetic acid, phenyllactic acid, tropic acid, 3-(phenylsulfonyl)propionic acid, 3,3-tetramethyleneglutaric acid, 5-oxoazelaic acid, azelaic acid, phenylsuccinic acid, 1,2-phenylenediacetic acid, 1,3 -Phenylenediacetic acid, 1,4-phenylenediacetic acid, benzylmalonic acid, sebacic acid, dodecanedioic acid, undecanedioic acid, diphenylacetic acid, benzilic acid, dicyclohexylacetic acid, tetradecanedioic acid, 2,2-diphenylpropionic acid, 3,3-diphenylpropionic acid, 4,4-bis(4-hydroxyphenyl)valeric acid (diphenolic acid), pimaric acid, palustric acid, isopimaric acid, abietic acid, dehydroabietic acid, neoabietic acid, agatic acid, benzoic acid, 2-hydroxybenzoic acid, 3-hydroxybenzoic acid, 4-hydroxybenzoic acid, 2,3-Dihydroxybenzoic acid, 2,4-dihydroxybenzoic acid, 2,5-dihydroxybenzoic acid, 2,6-dihydroxybenzoic acid, 3,4-dihydroxybenzoic acid, 2,3,4-trihydroxybenzoic acid, 2,4,6-trihydroxybenzoic acid, 3,4,5-trihydroxybenzoic acid, 1,2,3-benzenetricarboxylic acid, 1,2,4-benzenetricarboxylic acid, 1,3,5-benzenetricarboxylic acid, 2-[bis(4-hydroxyphenyl)methyl]benzoic acid, 1-naphthoic acid, 2- Examples of suitable hydroxybenzoic acids include naphthoic acid, 1-hydroxy-2-naphthoic acid, 2-hydroxy-1-naphthoic acid, 3-hydroxy-2-naphthoic acid, 6-hydroxy-2-naphthoic acid, 1,4-dihydroxy-2-naphthoic acid, 3,5-dihydroxy-2-naphthoic acid, 3,7-dihydroxy-2-naphthoic acid, 2,3-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 2-phenoxybenzoic acid, biphenyl-4-carboxylic acid, biphenyl-2-carboxylic acid, and 2-benzoylbenzoic acid. From the viewpoint of easily achieving excellent flux activity and the effects of the present invention, component (d) may contain benzilic acid, diphenylacetic acid, or a combination thereof.

[0098] The content of component (d) may be 0.1% by mass or more, 10% by mass or less, 5% by mass or less, or 2% by mass or less, based on the total solid content of the adhesive for semiconductors. From the viewpoint of connection reliability and reflow resistance during semiconductor device fabrication, the content of component (d) may be 0.1 to 10% by mass, 0.1 to 5% by mass, or 0.1 to 2% by mass, based on the total solid content of the adhesive for semiconductors. 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.

[0099] 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) may be 0.01 or more, or 4.8 or less. This molar ratio may be 0.1 or more, 0.5 or more, 4.0 or less, or 3.0 or less. Some of the reactive groups in component (c) and some of the acid groups in component (d) may form salts, and in this case, the ratio of the number of moles, including the number of reactive groups and acid groups that form the salt, may be within the above range.

[0100] 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) may be 0.01 to 4.8, 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) may be 0.01 to 4.8, 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) may be 0.01 to 2.4, and the ratio of the number of moles of tricarboxylic acids to the number of moles of reactive groups in the total amount of component (c) may be 0.01 to 1.6. 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) may be 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) may be 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) may be 0.5 / 3 to 1.0.

[0101] (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.

[0102] 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.

[0103] Examples of insulating inorganic fillers include glass, silica, alumina, titanium oxide, carbon black, mica, and boron nitride. The insulating inorganic filler may be selected from silica, alumina, titanium oxide, and boron nitride, or may be selected from silica, alumina, and boron nitride.

[0104] Whiskers include, for example, aluminum borate, aluminum titanate, zinc oxide, calcium silicate, magnesium sulfate, and boron nitride.

[0105] Examples of the resin filler include fillers made of resins such as polyurethane and polyimide.

[0106] 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 make it easy to adjust the viscosity of semiconductor adhesives. Resin fillers are superior in stress relief compared to inorganic fillers.

[0107] Inorganic fillers have a smaller coefficient of thermal expansion than resin fillers, and therefore can achieve a low coefficient of thermal expansion for adhesive compositions. Many inorganic fillers are general-purpose products with controlled particle sizes, making them suitable for viscosity adjustment.

[0108] 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.

[0109] There are no particular limitations on the shape, particle size, or content of component (e). Component (e) may have its physical properties appropriately adjusted by surface treatment.

[0110] The content of component (e) may be 10% by mass or more, or 15% by mass or more, or 80% by mass or less, or 60% by mass or less, based on the total solid content of the adhesive for semiconductors. The content of component (e) may be 10 to 80% by mass, or 15 to 60% by mass, based on the total solid content of the adhesive for semiconductors.

[0111] Component (e) is preferably made of an insulating material. If component (e) is made of a conductive material (e.g., solder, gold, silver, or copper), the insulation reliability (especially HAST resistance) may be reduced.

[0112] (Other ingredients) The adhesive for semiconductors 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.

[0113] 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.

[0114] 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 coating film is heated to remove the organic solvent, thereby forming a film-like adhesive on the substrate film.

[0115] The thickness of the film adhesive is not particularly limited, but may be, for example, 0.5 to 1.5 times, 0.6 to 1.3 times, or 0.7 to 1.2 times the height of the bump before connection.

[0116] 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. 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. In response to the weakening of bumps due to narrower pitches and more pins (miniaturization of bump diameter), eliminating a large amount of resin can potentially increase damage to the bumps.

[0117] Since the height of the bumps is generally 5 to 100 μm, the thickness of the film adhesive may be 2.5 to 150 μm, or 3.5 to 120 μm.

[0118] The organic solvent used in preparing the resin varnish may have the property of being able to uniformly dissolve or disperse each component. Examples of organic solvents include 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. Stirring, mixing, and kneading during the preparation of the resin varnish can be performed using, for example, a stirrer, a kneading machine, a three-roll mill, a ball mill, a bead mill, or a homodisper.

[0119] 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 also be a multilayer film made of two or more materials.

[0120] The drying conditions for volatilizing the organic solvent from the resin varnish applied to the substrate film may be any conditions that allow the organic solvent to volatilize sufficiently, and specifically may be heating at 50 to 200°C for 0.1 to 90 minutes. The organic solvent may be removed to 1.5 mass% or less of the total amount of the film-like adhesive.

[0121] The adhesive for a semiconductor of this embodiment may 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.

[0122] The minimum melt viscosity of the adhesive for semiconductors of this embodiment may be 400 to 2500 Pa·s, from the viewpoint that voids are more easily removed during curing under a pressurized atmosphere and more excellent reflow resistance is obtained. The minimum melt viscosity can be measured by the method described in the Examples. The temperature at which the adhesive for semiconductors exhibits the minimum melt viscosity (melting temperature) may be 100 to 200°C or 120 to 170°C.

[0123] From the viewpoint of facilitating temporary fixing of semiconductor chips in a temperature range of 60 to 155° C., the semiconductor adhesive of this embodiment may have a melt viscosity of 2000 to 10000 Pa·s at 80° C., or may have a melt viscosity of 500 to 5000 Pa·s at 130° C., or may have a melt viscosity of 2000 to 10000 Pa·s at 80° C. and a melt viscosity of 500 to 5000 Pa·s at 130° C. The melt viscosity can be measured by the method described in the examples.

[0124] 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 used in particular 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.

[0125] <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. The semiconductor device of this embodiment will be described below with reference to Figures 4, 5, and 6. Figures 4, 5, and 6 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.

[0126] FIG. 4 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. 4 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 as a connection portion disposed on the wiring or bumps 15. The substrate 2 includes a substrate body 20 and wiring or bumps 16 as a connection portion disposed on the surface of the substrate body 20 facing the semiconductor chip 1. 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 and are isolated from the external environment. The adhesive layer 40 can be a cured product of the above-mentioned adhesive for semiconductors.

[0127] 5 shows a COC type connection in which semiconductor chips are connected to each other. The configuration of the semiconductor device 300 shown in FIG. 5 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.

[0128] 5 and 6, the connection portion such as wiring or bump 15 may be a metal film (for example, gold plating) called a pad, or may be a post electrode (for example, copper pillar).

[0129] The semiconductor chip body 10 is not particularly limited, and can be a chip formed from various semiconductors such as elemental semiconductors composed of the same type of element, such as silicon or germanium, or compound semiconductors, such as gallium arsenide or indium phosphide.

[0130] 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.

[0131] Gold, silver, copper, solder, tin, nickel, etc. are used as the main component of the connection parts such as the wiring or bumps 15 and 16, solder 30, etc. The main component of the solder 30 may be, for example, tin-silver, tin-lead, tin-bismuth, tin-copper, or tin-silver-copper. The connection parts may be composed of only a single component, or may be composed of multiple components. The connection parts may have a structure in which these metals are laminated. Of the metal materials, copper and solder are relatively inexpensive. The connection parts may contain solder from the viewpoint of improving connection reliability and suppressing warpage.

[0132] The main component of the pad may be gold, silver, copper, solder, tin, nickel, or the like. The main component of the solder may be, for example, tin-silver, tin-lead, tin-bismuth, tin-copper, or tin-silver-copper. The pad may be composed of only a single component, or may be composed of 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.

[0133] A metal layer mainly composed of gold, silver, copper, solder, tin, nickel, etc. may be formed on the surface of the wiring or bumps 15, 16 (wiring pattern). The main component of the solder may be, for example, tin-silver, tin-lead, tin-bismuth, or tin-copper. 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.

[0134] Semiconductor devices (or semiconductor packages) such as those shown in FIG. 4 or 5 may be stacked and electrically connected using gold, silver, copper, solder, tin, nickel, or the like. The main component of the solder may be, for example, tin-silver, tin-lead, tin-bismuth, tin-copper, or tin-silver-copper. 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.

[0135] FIG. 6 is a cross-sectional view showing another embodiment of a semiconductor device. The semiconductor device 500 shown in FIG. 6 is a semiconductor chip stacking type TSV. In the semiconductor device 500 shown in FIG. 6, 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 patterned surfaces on the front and back of the semiconductor chip 1 are connected to each other by through electrodes 34 filled in holes penetrating the interior of the semiconductor chip body 10. The through electrodes 34 may be made of copper, aluminum, or the like.

[0136] 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.

[0137] <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 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. The sealing step includes heating the laminate (hereinafter sometimes referred to as a "temporary fixed body") obtained in the lamination step to a temperature equal to or higher than the melting point of the opposing connection portions to electrically connect the opposing connection portions, and curing the semiconductor adhesive by applying heat.

[0138] 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 arranging 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 temporary fixing bodies which are laminates each having a semiconductor chip, a semiconductor adhesive, and another semiconductor chip, which are stacked in this order.

[0139] When the first component is a wiring circuit board or a semiconductor wafer on which a plurality of semiconductor chips are mounted, the lamination 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 temporary fixing body having the wiring circuit board, the semiconductor adhesive, and a plurality of the semiconductor chips, or a temporary fixing body having the semiconductor wafer, the semiconductor adhesive, and a plurality of the semiconductor chips.

[0140] In the temporary fixing step, for example, a semiconductor adhesive is first placed on a first member or a second member. A film-like semiconductor adhesive may be attached to the first member or the second member. Next, 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.

[0141] 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. The semiconductor wafer on which the semiconductor adhesive has been disposed may be diced into individual pieces.

[0142] 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.

[0143] When the bonding tool picks up the semiconductor chip for temporary fixation, the bonding tool may be kept at a low temperature to prevent heat transfer to the semiconductor adhesive on the semiconductor chip. During the bonding (temporary bonding), the semiconductor chip may be heated to a relatively high temperature to increase the fluidity of the semiconductor adhesive and efficiently eliminate trapped voids. The semiconductor chip may be heated to a temperature lower than the initiation temperature of the curing reaction of the semiconductor adhesive. To shorten the cooling time, the difference between the temperature of the bonding tool when picking up the semiconductor chip and the temperature of the bonding tool when temporarily fixing the semiconductor chip may be small. This temperature difference may be 100°C or less, 60°C or less, or substantially 0°C. A temperature difference of 100°C or more tends to reduce productivity due to the long cooling time required for the bonding tool. The initiation temperature of the curing reaction of the semiconductor adhesive refers to the onset temperature of the exothermic peak of the curing reaction when 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.

[0144] 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, opposing connection portions may be 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 may be large to eliminate voids and ensure contact between the connection portions, and may be, for example, 0.009 N to 0.2 N per connection portion (e.g., bump).

[0145] From the viewpoint of improving productivity, the pressure bonding time in the temporary fixing step may be, for example, 5 seconds or less, 3 seconds or less, or 2 seconds or less.

[0146] 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 is usually 60 to 150° C. By heating at such a temperature, voids trapped in the adhesive for semiconductors can be efficiently eliminated.

[0147] When the lamination step includes the temporary fixing step, the sealing step following the temporary fixing step may involve collectively curing the semiconductor adhesive in the plurality of laminates or the laminate including the plurality of semiconductor chips to collectively seal the plurality of connection portions. The sealing step joins the opposing connection portions by metallic bonding, and typically fills the gaps between the connection portions with the semiconductor adhesive.

[0148] In the sealing process, the connection portions may be joined by heating the temporary fixing body at a temperature equal to or higher than the melting point of at least one of the metals of the opposing connection portions (e.g., bump-bump, bump-pad, bump-wiring). For example, if the metal of the connection portion is solder, the heating temperature may be 220°C or higher and 330°C or lower. If the heating temperature is low, the metal of the connection portion may not melt, and a sufficient metal bond may not be formed. If the heating temperature is excessively high, the effect of void suppression may be relatively small, and the solder may be more likely to splash. To join the connection portions, the temporary fixing body may be heated while being pressurized using a crimping machine. The semiconductor adhesive may be cured by heating for joining the connection portions. The curing reaction of the semiconductor adhesive may be partially promoted during heating for joining the connection portions, and then the semiconductor adhesive may be further cured by applying heat under a pressurized atmosphere. Examples of devices for heating under a pressurized atmosphere include a pressurized reflow furnace and a pressurized oven.

[0149] When pressure is applied to bond the connection portions using a crimping machine, heat from the crimping machine is not easily transferred to the semiconductor adhesive (fillet) that protrudes from the side of the connection portions. Therefore, after the crimping process, a heat treatment is often required to sufficiently promote the curing of the semiconductor adhesive. Therefore, the pressure in the sealing process may be applied by atmospheric pressure in a pressure reflow oven, pressure oven, or the like, rather than by a crimping machine. Heat may be applied in a pressurized atmosphere to bond the connection portions and cure the semiconductor adhesive. Pressure application by atmospheric pressure allows heat to be applied to the entire assembly, shortening or eliminating the post-compression heat treatment, thereby improving productivity. Pressure application by atmospheric pressure facilitates the simultaneous permanent compression bonding of multiple stacks (temporary fixtures) or stacks (temporary fixtures) including multiple temporarily fixed semiconductor chips. Pressure application by atmospheric pressure is more advantageous than direct pressure application using a crimping machine in terms of fillet suppression. Fillet suppression is important given the trend toward smaller and denser semiconductor devices.

[0150] The pressurized atmosphere in which pressure bonding is performed in the sealing step is not particularly limited, but may be an atmosphere containing air, nitrogen, formic acid, or the like.

[0151] 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. From the viewpoint of suppressing voids and improving connectivity, the pressure may be high. From the viewpoint of suppressing fillets, the pressure may be low. Therefore, the pressure may be 0.05 to 0.5 MPa.

[0152] The bonding time for the main bonding varies depending on the constituent metal of the connection portion, but a shorter time is preferable from the viewpoint of improving productivity. When the connection portion is a solder bump, the connection time may be 20 seconds or less, 10 seconds or less, or 5 seconds or less. When the metal connection is copper-copper or copper-gold, the connection time may be 60 seconds or less.

[0153] 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.

[0154] Fig. 7 is a schematic cross-sectional view showing one embodiment of a method for manufacturing a semiconductor device. In the method shown in Fig. 7, an adhesive layer 40A made of a semiconductor adhesive is interposed between a semiconductor chip 1 having a plurality of solders 30 as connecting portions and a semiconductor wafer 3 having a plurality of solders 32 as connecting portions, and the semiconductor chip 1, the semiconductor wafer 3, and the adhesive layer 40A are heated, whereby the connecting portions (solder 30) of the semiconductor chip 1 and the connecting portions (solder 32) of the semiconductor wafer 3 are electrically connected to each other, and a bonded body 95 is formed in which the electrically connected connecting portions (solder 30, 32) are sealed by the adhesive layer 40 made of the hardened semiconductor adhesive. More specifically, the process of forming the bonded body 95 includes placing the semiconductor wafer 3 on the stage 60 as shown in (a) of Figure 7; forming a temporary fixing body 90, which is a laminate consisting of the semiconductor wafer 3, the adhesive layer 40A, and the semiconductor chip 1 as shown in (b) of Figure 7; heating and pressurizing the temporary fixing body 90 to a temperature at which at least one of the solders 30 and 32, which are the connecting portions, melts as shown in (c) of Figure 7, thereby forming a bonded body 95, in which the solders 30 and 32, which are the connecting portions, are electrically connected, as shown in (d) of Figure 7; and heating the bonded body 95 in a pressurized atmosphere in a pressurized oven 85 as shown in (e) of Figure 7, thereby forming a hardened adhesive layer 40 that seals the connecting portions (solder 30 and 32).

[0155] The semiconductor chip 1 has a semiconductor chip body 10, wiring or bumps 15 provided on the semiconductor chip body 10, and solder 30 as a connection portion provided on the wiring or bumps 15. The semiconductor wafer 3 has a wafer body 11, wiring or bumps 15 provided on the wafer body 11, solder 32 as a connection portion provided on the wiring or bumps 15, and a passivation film 17 provided on the wafer body 11 and covering the wiring or bumps 15.

[0156] The temporary fixing body 90 is formed by thermocompression bonding the adhesive-attached semiconductor chip 1' to the semiconductor wafer 3 by a compression bonding tool 70 on a heated stage 60. The heating temperature of the stage 60 is lower than the melting points of the solders 30 and 32, and may be, for example, 60 to 150°C, or 70 to 100°C. The temperature of the compression bonding tool 70 may be, for example, 80 to 350°C, or 100 to 170°C. The time for thermocompression bonding to form the temporary fixing body 90 may be, for example, 5 seconds or less, 3 seconds or less, or 2 seconds or less.

[0157] The bonded body 95 is formed by applying pressure to the temporary fixing body 90 on the heated stage 60 using a crimping tool 80 while heating the temporary fixing body 90 to at least one of the melting points of the solder 30 and the solder 32. The temperature of the crimping tool 80 may be, for example, 180°C or higher, 220°C or higher, or 250°C or higher, or 350°C or lower, 320°C or lower, or 300°C or lower. The heating temperature of the stage 60 during thermocompression bonding to form the bonded body 95 may be 60 to 150°C, or 70 to 100°C. The time for thermocompression bonding by the crimping tool 80 to form the bonded body 95 may be, for example, 5 seconds or shorter, 3 seconds or shorter, or 2 seconds or shorter.

[0158] The adhesive layer 40A is sufficiently cured by heating and pressurizing in the pressure oven 85. However, the adhesive layer 40A may be partially cured during the heating and pressurizing process for forming the bonded body 95. The heating temperature in the pressure oven 85 may be a temperature that is lower than the melting point of the solders 30 and 32 and that allows the adhesive layer 40A to be cured, for example, 170 to 200°C.

[0159] A bonded structure 95 having a plurality of semiconductor chips 1 may be formed by sequentially mounting a plurality of semiconductor chips 1 on one semiconductor wafer 3 via an adhesive layer 40, and then the bonded structure 95 may be heated and pressurized in a pressure oven 85. In this case, the adhesive layer 40A between the semiconductor chips 1 initially placed on the semiconductor wafer 3 and the semiconductor wafer 3 continues to be subjected to a thermal history by the stage 60 until the mounting of all the semiconductor chips 1 is completed. Even after being subjected to a long period of thermal history, the adhesive layer 40A including the semiconductor adhesive according to the above-described embodiment can provide a bonded structure 95 with high reliability. [Example]

[0160] The present invention will be described in more detail below with reference to examples, although the present invention is not limited to these examples.

[0161] 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 "ZX1356-2", Tg: approx. 71°C, Mw: approx. 63,000) Phenoxy resin (manufactured by Nippon Steel & Sumikin Chemical Co., Ltd., product name "FX293", Tg: approximately 160°C, Mw: approximately 40,000)

[0162] (b) Component: Thermosetting resin - Multifunctional solid epoxy resin containing a triphenolmethane skeleton (manufactured by Mitsubishi Chemical Corporation, product name "EP1032H60") Bisphenol F liquid epoxy resin (manufactured by Mitsubishi Chemical Corporation, product name "YL983U")

[0163] (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) 2-Phenyl-4,5-dihydroxymethylimidazole (manufactured by Shikoku Chemicals Corporation, trade name "2PHZ-PW", Mw: 204)

[0164] (d) Component: Flux compound Diphenolic acid (Tokyo Chemical Industry Co., Ltd., melting point: 177°C, molecular weight: 286) Benzilic acid (Fujifilm Wako Pure Chemical Industries, Ltd., melting point: 152°C, molecular weight: 228) Diphenylacetic acid (Fujifilm Wako Pure Chemical Industries, Ltd., melting point: 149°C, molecular weight: 212) Glutaric acid (Fujifilm Wako Pure Chemical Industries, Ltd., melting point: 98°C, molecular weight: 132)

[0165] (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) Methacrylic surface-treated silica filler (manufactured by Admatechs Co., Ltd., product name "180nm SM-EH1", average particle size approximately 0.18μm)

[0166] (a) The weight average molecular weight (Mw) of the component was determined by the GPC method. The details of the GPC method are as follows. Apparatus name: HPLC-8020 (product name, manufactured by Tosoh Corporation) Columns: 2 pieces of GMHXL + 1 piece of G-2000XL Detector: RI detector Column temperature: 35 °C Flow rate: 1 mL / min Standard substance: Polystyrene

[0167] <Preparation of Adhesive for Film状 Semiconductor> A thermoplastic resin, a thermosetting resin, a curing agent, a flux compound, and a filler in the blending amounts (unit: parts by mass) shown in Table 1 were added to an organic solvent (cyclohexanone) so that the NV value ([mass of adhesive after drying] / [mass of coating varnish before drying] × 100) was 50%. In the same container as these mixtures, beads of Φ1.0 mm and zirconia beads of Φ2.0 mm with the same mass as the blending amount of the solid components (thermoplastic resin, thermosetting resin, curing agent, flux compound, and filler) were added, and the mixture was stirred with a ball mill (Fritsch Japan Co., Ltd., planetary type fine grinder P-7) for 30 minutes. After stirring, the zirconia beads were removed by filtration to prepare a coating varnish.

[0168] The obtained coating varnish was applied onto a base film (manufactured by Toyobo Film Solutions Co., Ltd., trade name "Purelex A55") using a small precision coating apparatus (Yasui Seiki). The coating film was dried at 100 °C for 10 minutes in a clean oven (manufactured by ESPEC) to obtain a film状 adhesive with a film thickness of 20 μm.

[0169] <DSC Measurement> 10 mg of the resulting film-like adhesive was weighed into an aluminum pan (manufactured by Epolead Services Co., Ltd.), covered with an aluminum lid, and the evaluation sample was sealed in the sample pan using a crimper. DSC measurements were performed using a differential scanning calorimeter (Thermo plus DSC8235E, manufactured by Rigaku Corporation) under a nitrogen atmosphere at a heating rate of 10°C / min over a measurement temperature range of 30 to 300°C. The calorific value was analyzed using a partial area analysis method. Analysis was instructed for each DSC curve in the temperature range of 60 to 280°C, and the total calorific value (unit: J / g) was calculated by specifying a baseline for the analysis temperature range and integrating the peak area. Next, 155°C was specified as the dividing temperature, and the partial areas from 60 to 155°C and from 155 to 280°C were integrated to calculate the calorific value (unit: J / g). On the other hand, as a means of analyzing the onset temperature, the total area analysis method (JIS method) was used, and by instructing the analysis in the temperature range of 60°C to 280°C, the intersection point of the baseline of the peak and the maximum slope point in each DSC curve was calculated, and the onset temperature (unit: °C) was obtained.

[0170] [Table 1] *In the table, the molar ratio r indicates the ratio of the number of moles of acid groups in the total amount of flux compound to the number of moles of reactive groups in the total amount of hardener.

[0171] The film adhesives obtained in the examples and comparative examples were evaluated using the following methods. The evaluation results are shown in Table 2.

[0172] <Film Formability Evaluation> The 20 μm film adhesives obtained in the examples and comparative examples were punched out by hitting them from above with a hammer using a punch (φ20 mm). If the punched sample was not cracked, it was rated as "A", and if it was cracked and / or chipped, it was rated as "B".

[0173] <High temperature storage stability evaluation> The DSC curve obtained above was analyzed to calculate the calorific value (unit: J / g) from 60 to 280° C. This was defined as the initial calorific value.

[0174] The film adhesives (initial samples) obtained in the Examples and Comparative Examples were placed in an oven set to 100°C and heat-treated for 1 hour. After heat treatment, the samples were removed to obtain evaluation sample A after heat treatment at 100°C.

[0175] The film-like adhesives (initial samples) obtained in the Examples and Comparative Examples were placed in an oven set to 80°C and heat-treated for 12 hours. After heat treatment, the samples were removed to obtain evaluation sample B after heat treatment at 80°C.

[0176] Using evaluation sample A and evaluation sample B, the calorific value (unit: J / g) from 60 to 280°C was calculated using the same procedure as before heating, and this was defined as the calorific value after treatment.

[0177] 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 10% was rated as "A," a response rate of 10% or more but less than 20% was rated as "B," and a response rate of 20% or more was rated as "C."

[0178] <Viscosity measurement> Using the initial samples and evaluation sample A of the examples and comparative examples, 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) were measured using a rotational rheometer (manufactured by TA Instruments, product name: ARES-G2). [Measurement conditions] Heating rate: 10°C / min Frequency: 10Hz Temperature range: 30~170℃

[0179] <Void evaluation> (Fabrication of semiconductor devices) The evaluation sample A prepared above was cut into a 7.5 mm square and attached to a semiconductor chip with multiple solder bumps (chip size: 7.3 mm × 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) at 80 °C. The semiconductor chip with the film-like adhesive attached was sequentially pressure-bonded 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), temporarily fixing the semiconductor chips together. Pressure-bonding conditions were 130 °C, 75 N, and 2 seconds.

[0180] The temporarily fixed laminate (temporarily fixed body) was heat treated in an oven at 100°C for 3 hours, then removed and heated and pressurized in a pressure oven at 200°C for 1 hour at 0.6 MPa to obtain a sample for void evaluation.

[0181] (Analysis and evaluation) The appearance of the sample was photographed using an ultrasound imaging diagnostic device (Insight-300, manufactured by Insight Corporation). From the obtained image, an image of the adhesive layer between the chips was captured using a scanner (GT-9300UF, manufactured by Seiko Epson Corporation). In the captured image, voids were identified by color correction and two-tone gradation using image processing software (Adobe Photoshop (trade name)), and the proportion of voids was calculated using a histogram. The area of ​​the entire adhesive layer, including voids, was taken as 100%. A void area percentage of less than 10% was assigned an "A," a void area percentage of 10% or more but less than 30% was assigned a "B," and a void area percentage of 30% or more was assigned a "C." The evaluation results are shown in Table 2.

[0182] [Table 2] [Explanation of symbols]

[0183] 1...semiconductor chip, 2...substrate, 3...semiconductor wafer, 10...semiconductor chip body, 11...wafer body, 15, 16...wiring or bump, 20...substrate body, 30, 32...solder, 34...through electrode, 40...adhesive layer, 50...interposer body, 90...laminated body (temporary fixed body), 95...bonded body, 100, 300, 500...semiconductor device.

Claims

1. A semiconductor adhesive comprising a thermoplastic resin, a thermosetting resin, a curing agent having a reactive group, and a flux compound having an acid group, The adhesive for semiconductors has a heat release value of 20 J / g or less between 60 and 155°C in a DSC curve obtained by differential scanning calorimetry in which the adhesive for semiconductors is heated at a temperature increase rate of 10°C / min.

2. 2. The adhesive for semiconductors according to claim 1, wherein the thermoplastic resin has a weight average molecular weight of 10,000 or more.

3. 3. The adhesive for semiconductors according to claim 1, wherein the content of the thermoplastic resin is 1 to 30 mass % based on the total solid content of the adhesive for semiconductors.

4. The adhesive for semiconductors according to any one of claims 1 to 3, wherein the curing agent includes an amine-based curing agent.

5. The adhesive for semiconductors according to any one of claims 1 to 4, wherein the curing agent comprises an imidazole-based curing agent.

6. 6. A semiconductor adhesive according to claim 1, wherein the content of the curing agent is 2.3 mass % or less based on the total solid content of the semiconductor adhesive.

7. The adhesive for semiconductors according to any one of claims 1 to 6, wherein the melting point of the flux compound is 25 to 230°C.

8. The adhesive for semiconductors according to any one of claims 1 to 7, wherein the thermosetting resin contains an epoxy resin.

9. The adhesive for semiconductors according to any one of claims 1 to 8, wherein the thermosetting resin does not substantially contain an epoxy resin that is liquid at 35°C.

10. The adhesive for semiconductors according to any one of claims 1 to 9, which is in the form of a film.

11. A semiconductor adhesive according to any one of claims 1 to 10, which is used to harden the semiconductor adhesive by applying heat under a pressurized atmosphere and seal the connection portion of a semiconductor chip with the hardened semiconductor adhesive.

12. The adhesive for semiconductors according to any one of claims 1 to 11, wherein the adhesive for semiconductors has a minimum melt viscosity of 400 to 2500 Pa·s.

13. A semiconductor adhesive according to any one of claims 1 to 12, wherein the ratio of the number of moles of the acid groups in the total amount of the flux compound to the number of moles of the reactive groups in the total amount of the curing agent is 0.01 to 4.

8.

14. The method includes a step of mixing a thermoplastic resin, a thermosetting resin, a curing agent having a reactive group, and a flux compound having an acid group, In the step, the curing agent and the flux compound are blended so that the ratio of the number of moles of the acid groups in the total amount of the flux compound to the number of moles of the reactive groups in the total amount of the curing agent is 0.01 to 4.

8.

15. the flux compound comprises at least one selected from the group consisting of a monocarboxylic acid, a dicarboxylic acid, and a tricarboxylic acid; 15. A method for manufacturing a semiconductor adhesive as described in claim 14, wherein in the process, the curing agent and the flux compound are blended so that the ratio of the number of moles of the monocarboxylic acid to the number of moles of the reactive groups in the total amount of the curing agent is 0.01 to 4.8, the ratio of the number of moles of the dicarboxylic acid to the number of moles of the reactive groups in the total amount of the curing agent is 0.01 to 2.4, and the ratio of the number of moles of the tricarboxylic acid to the number of moles of the reactive groups in the total amount of the curing agent is 0.01 to 1.

6.

16. The method for producing an adhesive for semiconductors according to claim 14 or 15, wherein the weight average molecular weight of the thermoplastic resin is 10,000 or more.

17. A method for producing a semiconductor adhesive according to any one of claims 14 to 16, wherein the blending amount of the thermoplastic resin is 1 to 30 mass% based on the total solid content of the semiconductor adhesive.

18. The method for producing a semiconductor adhesive according to any one of claims 14 to 17, wherein the curing agent includes an amine-based curing agent.

19. The method for producing a semiconductor adhesive according to any one of claims 14 to 18, wherein the curing agent includes an imidazole-based curing agent.

20. A method for producing a semiconductor adhesive according to any one of claims 14 to 19, wherein the amount of the curing agent is 2.3 mass% or less based on the total solid content of the semiconductor adhesive.

21. The method for producing a semiconductor adhesive according to any one of claims 14 to 20, wherein the melting point of the flux compound is 25 to 230°C.

22. The method for producing an adhesive for a semiconductor according to any one of claims 14 to 21, wherein the thermosetting resin contains an epoxy resin.

23. The method for producing an adhesive for a semiconductor according to any one of claims 14 to 22, wherein the thermosetting resin does not substantially contain an epoxy resin that is liquid at 35°C.

24. A method for producing a semiconductor adhesive according to any one of claims 14 to 23, further comprising a step of forming a mixture containing the thermoplastic resin, the thermosetting resin, the curing agent, and the flux compound into a film.

25. A method for manufacturing 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 method for manufacturing a semiconductor device in which the connection portions of multiple semiconductor chips are electrically connected to each other, comprising a sealing step of hardening a semiconductor adhesive described in any one of claims 1 to 13 by applying heat, and sealing at least a portion of the connection portion with the hardened semiconductor adhesive.

26. Before the sealing step, placing a plurality of semiconductor chips on a stage; 26. The method for manufacturing a semiconductor device according to claim 25, 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, to obtain a plurality of stacks each having the semiconductor chip, the semiconductor adhesive, and the other semiconductor chip, stacked in this order.

27. Before the sealing step, placing a printed circuit board or a semiconductor wafer on a stage; 26. The method for manufacturing a semiconductor device according to claim 25, further comprising a temporary fixing process in which, while heating the stage to 60 to 155°C, a plurality of semiconductor chips are sequentially arranged on the wiring circuit board or semiconductor wafer arranged on the stage via the semiconductor adhesive, to obtain a laminate having the wiring circuit board, the semiconductor adhesive, and a plurality of the semiconductor chips stacked in this order, or a laminate having the semiconductor wafer, the semiconductor adhesive, and a plurality of the semiconductor chips stacked in this order.

28. A semiconductor device comprising a semiconductor chip having a connection portion and a wiring circuit board having a connection portion, wherein the connection portion of the semiconductor chip and the connection portion of the wiring circuit board are electrically connected to each other; or A semiconductor device comprising a plurality of semiconductor chips each having a connecting portion, the connecting portions of the semiconductor chips being electrically connected to each other, A semiconductor device, wherein at least a portion of the connection portion is sealed with a cured product of the adhesive for semiconductors according to any one of claims 1 to 13.

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