Manufacturing method of the joint

Abstract

To provide a method for producing a zygote capable of preventing contamination of a non-joint member due to a buffering material, even when producing the zygote due to heating and pressing time of a laminate using a buffering material, and a method for producing that guarantees bulk zygosity due to the buffering material, and a method for producing that guarantees the bulk zygosity when a plurality of laminates is arranged on the same pressing tools.SOLUTION: A method for producing a zygote in which a first material to be joined and a second material to be joined are joined, the method comprises: arranging a membrane body on the first material to be joined; placing the second material to be joined on the membrane body to form a laminate; and arranging a pressing tool on an edge face in a lamination direction of the laminate, and prior to applying heat and pressure on the laminate to join the first material to be joined and the second material to be joined, a metal material is arranged on the laminate and the buffer material is arranged on the metal material.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a method for producing a bonded body and a method for preventing adhesion of a buffer material.

Background Art

[0002] Conventionally, there has been known a semiconductor device in which a semiconductor element and a substrate such as a circuit board are sinter-bonded using a sinterable bonding material containing metal fine particles. For example, in a method for manufacturing a semiconductor device such as an IGBT through which a large current flows and which generates a large amount of heat, the use of harmful chemical substances instead of solder is restricted, and a sintering precursor containing metal fine particles excellent in heat dissipation is used, and a step of sinter-bonding a semiconductor element and a circuit board or the like is employed.

[0003] However, when a bonded body is produced by heating and pressurizing a laminate in which members to be bonded such as a semiconductor element and a circuit board are laminated via a bonding layer, one of the members to be bonded may suffer damage such as scratches due to the heating and pressurization. In view of such a problem, Patent Document 1 attempts to interpose a buffer material such as polytetrafluoroethylene (PTFE) between a pressing member and the laminate during heating and pressing, and heat and press the laminate via the buffer material.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problem to be Solved by the Invention

[0005] However, when a buffer material such as a resin sheet or PTFE is interposed between the laminate and the pressurizing member, a problem arises in that during heating and pressurizing, the components of the buffer material fuse to the adjacent and contacting members to be bonded, contaminating the members to be bonded. This contamination causes various problems, such as hindering wire bonding to the members to be bonded when the members to be bonded are semiconductor elements. Furthermore, when multiple laminates are arranged on the same pressing jig and multiple bonded bodies are manufactured simultaneously, it is difficult to ensure consistent bonding in a single batch.

[0006] Therefore, the object of the present invention is to provide a method for manufacturing a bonded body that can prevent contamination of the members to be joined by the cushioning material even when the bonded body is manufactured by heating and pressurizing a laminated body using a cushioning material, and a manufacturing method that ensures simultaneous joining when multiple bonded bodies are manufactured at the same time by arranging multiple laminated bodies on the same pressing jig. Furthermore, the phrase "ensuring simultaneous bonding when multiple laminates are placed on the same pressing jig and multiple bonded bodies are manufactured simultaneously" will also be referred to as "ensuring simultaneous bonding" below. [Means for solving the problem]

[0007] As a result of diligent research to solve the above problems, the present inventors have found that by placing a buffer material between a laminate consisting of a first material to be joined, a film, and a second material to be joined, and a pressing jig, and by placing a predetermined metal material between the buffer material and the second material to be joined, contamination of the second material to be joined by the buffer material can be prevented, and simultaneous joining of multiple joined bodies can be ensured.

[0008] In other words, the present invention is a method for manufacturing a joined body in which a first material to be joined and a second material to be joined are joined together. A step of arranging a film on the first material to be bonded, A step of placing the second material to be joined on the film to form a laminate, The process includes the step of arranging a pressing jig on the end face of the laminate in the stacking direction, The present invention provides a method for manufacturing a joined body, wherein, prior to heating and pressurizing the laminate using the aforementioned pressing jig to join the first to be joined material and the second to be joined material, a metal material is placed on the laminate and a cushioning material is placed on the metal material.

[0009] Furthermore, in the present invention, when preparing a laminate in which a first material to be joined, a film, and a second material to be joined are stacked in this order, a pressing jig is placed on the end face of the laminate in the stacking direction, a cushioning material is placed between the laminate and the pressing jig, the laminate is heated and pressurized using the pressing jig, and a joined body is manufactured by joining the first material to be joined and the second material to be joined, The present invention provides a method for preventing the adhesion of a cushioning material, which involves arranging a metal material between the laminate and the cushioning material to prevent the cushioning material from adhering to the joint. [Effects of the Invention]

[0010] According to the present invention, even when manufacturing a bonded body by heating and pressurizing a laminated body using a cushioning material, it is possible to prevent contamination of the members to be joined by the cushioning material, and to provide a manufacturing method that ensures simultaneous joining when manufacturing multiple bonded bodies at the same time. [Brief explanation of the drawing]

[0011] [Figure 1] Figure 1 is a schematic diagram showing the steps of the manufacturing method for the jointed body of the present invention. [Modes for carrying out the invention]

[0012] The present invention will be described below based on its preferred embodiments. Figure 1 is a process diagram illustrating the joining method of the jointed body according to the present invention.

[0013] First, as shown in Figure 1, a film 12X is placed on the first workpiece 11. The film functions to join the first workpiece and the second workpiece, as described below, and examples include a metal sheet, a metal foil, or other flat metal body, a sintered bonding material containing metal nanoparticles, or a bonding paste utilizing transitional liquid-phase sintering (TLPS), which is a sintered precursor that is formed flat by coating. The film 12X may be placed to join the first workpiece 11 with a predetermined bonding material, or it may simply be placed on top.

[0014] As the aforementioned film, for example, a sintered precursor containing metal nanoparticles can be used. This sintered precursor can be, for example, a paste, a dried paste, or a sheet containing metal nanoparticles and at least one of a resin and an organic solvent. Specifically, a member having a metal surface can be used as the first material to be bonded, and the aforementioned sintered precursor can be used as the film 12X. When a paste is used as the sintering precursor, it is preferable to directly coat the paste onto the first material to be joined. When a dried paste is used as the sintering precursor, it is preferable to directly coat the paste onto the first material to be joined and dry it to obtain a dried paste. When a sheet is used as the sintering precursor, the sheet can be pressed onto the first material to be joined, or it can be used without pressing. When used without pressing, it is preferable to use a temporary fixing composition between the sheet and a support base made of metal such as copper.

[0015] The method for applying the paste is not particularly limited, but examples include screen printing, gravure printing, dispensing, reverse coating, and doctor blade methods.

[0016] The metal fine particles contained in the sintering precursor are not particularly limited, but from the viewpoint of improving the bondability between the first member to be bonded 11 and the second member to be bonded 13 located above and below the film body 12X after sintering, particles of copper, silver, palladium, zinc, aluminum, gold or nickel, or mixtures or alloys of these are preferred. From the viewpoint of maintaining good bondability between the first member to be bonded 11 and the second member to be bonded 13, when the film body 12X contains volatile components such as in a paste, the thickness thereof is preferably 1 µm or more and 300 µm or less. In the case of a product that does not contain volatile components, such as a dried paste or a sheet, the thickness is preferably 0.8 µm or more and 240 µm or less so that the bonding layer described later can ensure sufficient bonding strength.

[0017] Volume cumulative particle diameter D of metal fine particles SEM50 is preferably 0.01 µm or more and 30 µm or less from the viewpoint of maintaining good bonding between the first member to be bonded and the second member to be bonded. From the same viewpoint, D SEM50 is more preferably 0.03 µm or more and 20 µm or less, and even more preferably 0.05 µm or more and 15 µm or less. Volume cumulative particle diameter D SEM50 is obtained, for example, by the following measurement method. The magnification is appropriately adjusted with a scanning electron microscope (SEM), and metal fine particles with clear outlines are photographed. After reading the SEM image of the metal fine particles using Mac-View manufactured by Mountech Co., Ltd., 50 or more metal fine particles on the SEM image are randomly selected, and the particle diameter (Heywood diameter) of the particles is measured. Next, from the obtained Heywood diameter, the volume when the particle is assumed to be a true sphere is calculated, and the particle diameter at 50% by volume of the cumulative volume is taken as the volume cumulative particle diameter D SEM50 .

[0018] There is no particular limitation on the shape of the metal fine particles, and examples thereof include spherical, polyhedral, flat, irregular shapes, or combinations thereof. Further, the metal fine particles may have two or more peaks in their particle size distribution.

[0019] The metal fine particles may have a surface treatment agent attached to their surfaces. By having a surface treatment agent attached to the surfaces of the metal fine particles, excessive aggregation and oxidation of the metal fine particles can be suppressed.

[0020] The surface treatment agent is not particularly limited, and for example, fatty acids, aliphatic amines, silane coupling agents, titanate coupling agents, aluminate coupling agents and the like can be used. By using these, it is possible to interact with the surfaces of the particles, improve the compatibility with the organic solvent contained in the paste and the resin in the sheet, improve the fluidity of the paste, and prevent oxidation of the particle surfaces. Specific examples of fatty acids or aliphatic amines include benzoic acid, pentanoic acid, hexanoic acid, octanoic acid, nonanoic acid, decanoic acid, lauric acid, palmitic acid, oleic acid, stearic acid, pentylamine, hexylamine, octylamine, decylamine, laurylamine, oleylamine, stearylamine, and the like. These fatty acids and aliphatic amines can each be used alone in one kind, or in combination of two or more kinds.

[0021] The paste and the sintering precursor which is a dried product of the paste may appropriately contain a regulator for adjusting various properties of the paste and the sintering precursor. Examples of the regulator include a reducing agent, a viscosity regulator, and a surface tension regulator.

[0022] As the reducing agent, those that promote sintering of the metal fine particles are preferred, and examples thereof include monoalcohols, polyhydric alcohols, amino alcohols, citric acid, oxalic acid, formic acid, ascorbic acid, aldehydes, hydrazine and derivatives thereof, hydroxylamine and derivatives thereof, dithiothreitol, phosphite, hydrophosphite, phosphorous acid and derivatives thereof, and the like.

[0023] As the viscosity regulator, any agent that can adjust the viscosity level of the paste is acceptable, and examples thereof include ketones, esters, alcohols, glycols, hydrocarbons, polymers, and the like.

[0024] The surface tension modifier can be any agent capable of adjusting the surface tension of the paste, and examples include polymers such as acrylic surfactants, silicone surfactants, alkyl polyoxyethylene ethers, and fatty acid glycerol esters, as well as monomers such as alcohols, hydrocarbons, esters, and glycols.

[0025] When obtaining a dried product from a paste, it is not necessary to remove the entire amount of the organic solvent; it is sufficient to remove the organic solvent to the extent that the paste coating loses its fluidity. Therefore, some organic solvent may remain in the sintering precursor. The proportion of organic solvent contained in the sintering precursor can be, for example, 15% by mass or less, and in particular, 10% by mass or less.

[0026] The aforementioned organic solvent is not particularly limited in type, as long as it can disperse metal nanoparticles into a paste. Examples of organic solvents include monoalcohols, polyhydric alcohols, polyhydric alcohol alkyl ethers, polyhydric alcohol aryl ethers, polyethers, esters, nitrogen-containing heterocyclic compounds, amides, amines, terpene alcohols, ketones, and saturated hydrocarbons. These organic solvents can be used individually or in combination of two or more.

[0027] Examples of monoalcohols that can be used include 1-propanol, 1-butanol, 1-pentanol, 1-hexanol, cyclohexanol, 1-heptanol, 1-octanol, 1-nonanol, 1-decanol, glycidol, benzyl alcohol, methylcyclohexanol, 2-methyl-1-butanol, 3-methyl-2-butanol, 4-methyl-2-pentanol, 2-propanol, 2-ethylbutanol, 2-ethylhexanol, 2-octanol, 2-methoxyethanol, 2-ethoxyethanol, 2-n-butoxyethanol, and 2-phenoxyethanol.

[0028] Examples of polyhydric alcohols that can be used include ethylene glycol, propylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, diethylene glycol, dipropylene glycol, triethylene glycol, tetraethylene glycol, and hexylene glycol.

[0029] Examples of polyhydric alcohol alkyl ethers that can be used include ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, and propylene glycol monobutyl ether.

[0030] As polyhydric alcohol aryl ethers, ethylene glycol monophenyl ether, etc., can be used. As polyethers, polyethylene glycol, polypropylene glycol, etc., can be used. As esters, ethyl cellosolve acetate, butyl cellosolve acetate, γ-butyrolactone, etc., can be used. As nitrogen-containing heterocyclic compounds, N-methylpyrrolidone, 1,3-dimethyl-2-imidazolidinone, etc., can be used. As amides, formamide, N-methylformamide, N,N-dimethylformamide, etc., can be used. As amines, monoethanolamine, diethanolamine, triethanolamine, tripropylamine, tributylamine, etc., can be used. As terpene alcohols, isobornylcyclohexanol, terpineol, etc., can be used. As ketones, methyl ethyl ketone, etc., can be used. As saturated hydrocarbons, for example, heptane, octane, nonane, decane, undecane, dodecane, tridecane, tetradecane, pentadecane, hexadecane, etc., can be used.

[0031] Furthermore, in sintering precursors consisting of sheets in which metal fine particles are dispersed in resin, the resin can be, for example, various polyolefin resins such as polyethylene, polypropylene, polymethylpentene, and copolymers thereof; various polyamide resins such as nylon 6, nylon 66, nylon 12, nylon 11, metaxylylene adipamide (mXD6), hexamethylene terephthalamide (6T), and copolymers thereof; polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyethylene-2,6-naphthalate (PEN), polymethylene terephthalate (PMT), polypropylene terephthalate (PPT), polyethylene-p-oxybenzoate Examples of materials include polyesters copolymerized with poly-1,4-cyclohexylenedimethylene terephthalate (PCT) and various polyester resins such as diol components like diethylene glycol, neopentyl glycol, and polyalkylene glycol, or dicarboxylic acid components like adipic acid, sebatic acid, phthalic acid, isophthalic acid, and 2,6-naphthalenedicarboxylic acid. Other examples include thermoplastic resins such as acrylic resin, methacrylic resin, polyacetal (POM) resin, polyphenylene sulfide (PPS) resin, polycarbonate resin, polyvinyl chloride (PVC), and polyvinylidene chloride (PVdC). Thermosetting resins such as phenolic resin, epoxy resin, urea resin, melamine resin, and silicone resin may also be used.

[0032] Next, as shown in Figure 1, the second material to be joined 13 is placed on the film 12X to form a laminate 15.

[0033] There are no particular restrictions on the types of the first material to be joined 11 and the second material to be joined 13. Generally, it is preferable that both the first material to be joined 11 and the second material to be joined 13 contain metal on their joining surfaces. For example, at least one of the first material to be joined 11 and the second material to be joined 13 may be a member having a metal surface. Here, "metal" refers to the metal itself that does not form a compound with other elements, or an alloy of two or more types of metals. Examples of such metals include copper, silver, gold, aluminum, palladium, nickel, or alloys consisting of two or more of these. If it is composed of two or more types of metal, the surface may be an alloy. The metal surface is generally preferably flat, but may be curved in some cases. The second material to be joined 13 can be placed on the film 12X such that, in a plan view, its periphery is located inward, at the same level as, or outward from the periphery of the film 12X.

[0034] Specific examples of the first material to be joined 11 and the second material to be joined 13 include, independently, spacers, heat sinks, semiconductor elements made of the aforementioned metals, and substrates having at least one of the aforementioned metals on their surface. As substrates, for example, insulating substrates having a metal layer such as copper on the surface of ceramics, silicon nitride, or aluminum nitride plates can be used. When a semiconductor element is used as the material to be joined, the semiconductor element contains one or more elements such as Si, Ga, Ge, C, N, and As. The first material to be joined 11 is preferably a substrate. The second material to be joined 13 is preferably a spacer, a heat sink, or a semiconductor element.

[0035] Next, the laminate 15 is clamped with a predetermined pressing jig 16, and a metal material 17 is placed between the laminate 15 and the pressing jig 16, so that the metal material 17 is in contact with the laminate 15, specifically the second material to be joined 13, and a buffer material 18 is placed on the metal material 17. In the embodiment shown in Figure 1, the buffer material 18 is placed between the second material to be joined 13 in the laminate 15 and the pressing jig 16, and the metal material 17 is placed between the second material to be joined 13 and the buffer material 18. As a result, heating and pressurizing as described below can be performed without damaging the surface of the laminate 15, specifically the second material to be joined 13, and without the components of the buffer material 18 fusing (adhering) to the surface of the second material to be joined 13, and a joined body of the first material to be joined 11 and the second material to be joined 13 can be manufactured.

[0036] The cushioning material 18 mitigates damage to the laminate 15 during the heating and pressurizing process described below (in this embodiment, it mitigates damage to the second joined material 13 in the laminate 15), and is also effective in ensuring batch bonding when manufacturing multiple joined bodies simultaneously. Here, batch bonding refers to the evaluation that when multiple laminates are heated and pressurized and bonded using the same pressing jig, and multiple joined bodies are manufactured simultaneously, the desired bonding strength is ensured in all of those joined bodies. The desired bonding strength is preferably 40 MPa or more in all joined bodies. The cushioning material 18 is preferably composed of at least one selected from the group consisting of, for example, fluororesin, silicone resin, and carbon fiber. In Figure 1, the cushioning material 18 is formed in a sheet shape, but the shape of the cushioning material 18 does not necessarily have to be sheet-shaped; it may be any shape that provides a cushioning effect. For example, it may be lattice-shaped, linear, etc. In a plan view, the cushioning material 18 is arranged on the second joined material 13 so as to extend outward from the periphery of the second joined body 13. The cushioning material 18 may cover multiple laminates on the same pressing jig collectively, or it may cover each laminate individually.

[0037] The thickness of the cushioning material 18 is preferably 5 μm to 500 μm, more preferably 10 μm to 450 μm, and even more preferably 20 μm to 400 μm, from the viewpoint of ensuring jointability. The cushioning material 18 may be a single layer, or it may be one or more layers of two or more types.

[0038] The metal material 17 ensures the cushioning effect of the cushioning material 18 while preventing the components of the cushioning material 18 from adhering to the laminate 15 (or, in this embodiment, to the second material to be joined 13) during the heating and pressurizing process described below.

[0039] From the viewpoint of minimizing damage to the surface of the second joined material 13, the metal material 17 is preferably made of a metal or alloy with an elastic modulus of 250 GPa or less. Examples of such metals include aluminum (76 GPa), nickel (205 GPa), silver (100 GPa), gold (88 GPa), copper (136 GPa), and iron (190 GPa), and it is preferable that the metal material 17 consists of at least one selected from the group consisting of these, and examples of alloys include alloy steel mainly composed of iron, such as stainless steel. More preferably, from the viewpoint of easily ensuring a cushioning effect, the metal material 17 is preferably made of at least one selected from the group consisting of aluminum, silver, gold, copper, iron, etc., with an elastic modulus of 200 GPa or less.

[0040] From the viewpoint of not scratching the laminate 15 (the second material to be joined in this embodiment), the arithmetic mean roughness Sa of the surface of the metal material facing the laminate, measured in accordance with ISO 25178, is preferably 400 μm or less, more preferably 300 μm or less, and even more preferably 250 μm or less. There is no particular limit to the lower limit of the arithmetic mean roughness Sa; the smaller the value, the less likely the laminate 15 (the second material to be joined in this embodiment) is to be scratched.

[0041] The thickness of the metal material 17 is preferably 0.01 μm to 200 μm, more preferably 0.1 μm to 180 μm, and even more preferably 0.5 μm to 150 μm, from the viewpoint of handling and providing uniform bonding strength. The metal material 17 may be a single layer, or it may be one or more layers of two or more types.

[0042] From the viewpoint of workability, the ratio of the thickness of the cushioning material 18 to the thickness of the metal material 17 is preferably 0.025 or more and 50000 or less, and more preferably 0.05 or more and 4500 or less. Furthermore, the cushioning material 17 and the metal material 18 can be used individually, or they can be used as a single unit, for example, a cushioning material with the metal material laminated on one side by a sputtering method or the like.

[0043] In Figure 1, a buffer material 18 is placed between the metal material 17 and the pressing jig 16 so as to cover the entire upper surface of the metal material 17. However, the shape of the buffer material is not particularly limited as long as it extends in a two-dimensional direction perpendicular to the lamination direction of the laminate 15. For example, it may be lattice-shaped, linear, plate-shaped, or sheet-shaped. In plan view, the buffer material 18 is arranged to extend outward from the periphery of the second joining material 13.

[0044] Next, the laminate 15 is heated, and pressure is applied between the first material to be joined 11 and the second material to be joined 13 of the laminate 15 using a pressing jig 16. This step is a firing step for the film 12X, and in this step the film 12X is fired to become a bonding layer 12 for the first material to be joined 11 and the second material to be joined 13. Regarding the timing of heating and pressurizing, pressurizing may be performed under heating, heating under pressurizing, or pressurizing and heating may be performed simultaneously, and the order does not matter.

[0045] The heating temperature of the laminate 15 is specifically 180°C to 400°C, more preferably 200°C to 350°C. By setting the heating temperature within this range, the sintering of copper particles and the like in the film 12X is promoted, ensuring sufficient bonding strength between the second workpiece 13 and the first workpiece 11, and preventing the second workpiece 13 from being damaged by heat. The heating time is preferably 1 second to 60 minutes, and more preferably 1 minute to 30 minutes. Heating can be carried out using any of the following: an oxygen-containing atmosphere such as air, an inert atmosphere such as nitrogen, or a hydrogen-containing atmosphere.

[0046] The pressure is preferably 1 MPa to 40 MPa, and more preferably 10 MPa to 30 MPa, from the viewpoint of ensuring sufficient bonding strength with the first material to be joined 11 and the second material to be joined 13. The pressure holding time is preferably 1 second to 60 minutes, and more preferably 1 minute to 30 minutes. Through this heating and pressurizing process, the first material to be joined 11 and 13 are joined together as a single unit.

[0047] According to the manufacturing method of the present invention, it is possible to manufacture a bonded body or the like included in a semiconductor device.

[0048] Although the present invention has been described above based on its preferred embodiments, the present invention is not limited to the above embodiments. For example, in the above embodiments, the metal material 17 and the cushioning material 18 were arranged on the side of the laminate 15 where the second material to be joined 13 is located, but instead, the metal material 17 and the cushioning material 18 may be arranged on the side of the laminate 15 where the first material to be joined 11 is located. Alternatively, the metal material 17 and the cushioning material 18 may be arranged on both the side of the laminate 15 where the first material to be joined 11 is located and the side where the second material to be joined 13 is located, respectively.

[0049] Furthermore, although the metal material 17 and the cushioning material 18 were separate components in the above embodiment, a composite material in which the metal material 17 and the cushioning material 18 are integrated may be used instead. For example, a composite material may be used in which the metal material 17 is formed on one side of the cushioning material 18 by a sputtering method or the like, and prior to heating and pressurizing the laminate 15 with the pressing jig 16, the composite material may be placed between the laminate 15 and the pressing jig 16 so that the metal surface is in contact with the laminate 15, and then the first material to be joined 11 and the second material to be joined 13 may be joined.

[0050] Furthermore, this disclosure also encompasses the following inventions. [1] A method for manufacturing a joined body in which a first material to be joined and a second material to be joined are joined together, A step of arranging a film on the first material to be bonded, A step of placing the second material to be joined on the film to form a laminate, The process includes the step of arranging a pressing jig on the end face of the laminate in the stacking direction, A method for manufacturing a joined body, comprising: heating and pressurizing the laminate using the pressing jig to join the first to be joined and the second to be joined, before arranging a metal material on the laminate and arranging a cushioning material on the metal material. [2] The method for manufacturing a joint according to [1], wherein the metal material is a metal or alloy having an elastic modulus of 250 GPa or less. [3] The method for manufacturing a joint according to [1] or [2], wherein the cushioning material consists of at least one selected from the group consisting of fluororesin, silicone resin, and carbon fiber. [4] A method for manufacturing a bonded body according to any one of [1] to [3], wherein the thickness of the metal material is 0.01 μm or more and 200 μm or less. [5] A method for manufacturing a joint according to any one of [1] to [4], wherein the thickness of the cushioning material is 5 μm or more and 500 μm or less. [6] A method for manufacturing a bonded body according to any one of [1] to [5], wherein the arithmetic mean roughness Sa of the surface of the metal material facing the laminate, measured in accordance with ISO 25178, is 400 μm or less. [7] A method for manufacturing a bonded body according to any one of [1] to [6], wherein the first material to be bonded is a substrate and the second material to be bonded is a semiconductor element. [8] The film body is a sintering precursor containing metal fine particles, the method for producing a bonded body according to any one of [1] to [7]. [9] The method for producing a bond according to [8], wherein the sintering precursor containing the metal fine particles comprises particles of copper, silver, palladium, zinc, aluminum, gold, or nickel, or mixtures thereof or alloys thereof, as the metal fine particles.

[10] When manufacturing a joined body by preparing a laminate in which a first material to be joined, a film body and a second material to be joined are stacked in this order, and a pressing jig is placed on the end face of the laminate in the stacking direction, and a cushioning material is placed between the laminate and the pressing jig, and the first material to be joined and the second material to be joined are joined while the laminate is heated and pressurized using the pressing jig, A method for preventing the adhesion of a cushioning material, comprising arranging a metal material between the laminate and the cushioning material to prevent the cushioning material from adhering to the joint. [Examples]

[0051] The present invention will be described in more detail below with reference to examples. However, the scope of the present invention is not limited to these examples. Also, unless otherwise specified, "%" means "mass%".

[0052] [Example 1] (1) Preparation of paste Copper particles (spherical, D 50 A paste was prepared by mixing (0.16 μm) hexylene glycol and polyethylene glycol 300 as organic solvents and bis(2-hydroxyethyl)iminotris(hydroxymethyl)methane, a type of amino alcohol, as a reducing agent. The paste contained 82% copper particles, 17.9% organic solvent, and 0.1% reducing agent.

[0053] (2) Application of paste to the first workpiece A bonding paste was applied by screen printing onto a substrate, which served as the first material to be bonded, consisting of a copper plate (20 mm x 20 mm, 2.0 mm thick), to form a rectangular coating with dimensions of 0.6 cm x 0.6 cm. This coating was dried in an atmospheric environment at 110°C for 20 minutes to remove the organic solvent, thereby forming a film body consisting of a dried sintered precursor.

[0054] (3) Placing the second material to be bonded onto the dried coating (formation of a laminate) As the second material to be bonded, a SiC Schottky diode bare chip GP3D050A120X manufactured by SemiQ, Inc. was prepared (4.93 mm × 4.93 mm, thickness 0.200 ± 0.025 mm, anode electrode: Al, cathode electrode: Ni / Ag). Next, the Ni / Ag side of this SiC chip was placed in the center of the dried film, and a load of 0.8 MPa for 2 seconds was applied to form a laminate in which the first material to be bonded, the film, and the second material to be bonded were stacked in that order.

[0055] (4) Placement of cushioning material and metal material Next, an aluminum foil (product name LUXAL, 10mm x 10mm, 60μm thick, manufactured by Toyo Aluminum Co., Ltd.) with an arithmetic mean roughness Sa of 8.9μm, measured in accordance with ISO 25178, was placed on the SiC chip as a metal material. Furthermore, a PTFE material (product name 900UL, 10mm x 10mm, 50μm thick) was placed on the aluminum foil as a buffer material.

[0056] (5) Firing of the laminate (for evaluation of contamination and scratches on SiC chips) (4) The laminate with the buffer material and metal material arranged was placed on a pressing jig, and pressure was applied in a nitrogen atmosphere through the buffer material and metal material until a pressure of 20 MPa was reached between the first and second materials to be joined. The laminate was then heated to 300°C. The holding time was 20 minutes, the heating rate was set to an average of 17.3°C / second, and the pressure increase rate was set to 1.3 MPa / second. In this way, a joint consisting of the first and second materials to be joined was manufactured.

[0057] (6) Firing of the laminate (for evaluation of joint bonding properties) In (4), four laminates with the cushioning material and metal material arranged were placed on a pressing jig, and then pressure was applied in a nitrogen atmosphere until a pressure of 20 MPa was reached between each first and second joined member. After that, the laminates were heated to 300°C. The holding time was 20 minutes, the heating rate was set to an average of 17.3°C / second, and the pressure increase rate was set to 1.3 MPa / second. In this way, four joined bodies consisting of the first and second joined members were manufactured in one batch.

[0058] [Example 2] The bonded body was manufactured in the same manner as in Example 1, except that the metal material used was 8021 material (manufactured by Toyo Aluminum Co., Ltd.), which is an Al foil with a thickness of 35 μm and an arithmetic mean roughness Sa of 60 μm measured in accordance with ISO 25178.

[0059] [Example 3] The bonded body was manufactured in the same manner as in Example 2, except that the metal material used was 8021 material (manufactured by Toyo Aluminum Co., Ltd.), which is an Al foil with a thickness of 35 μm and an arithmetic mean roughness Sa of 238.7 μm as measured in accordance with ISO 25178.

[0060] [Comparative Example 1] The joint was manufactured in the same manner as in Example 1, except that no metal material was used.

[0061] [Comparative Example 2] The joint was manufactured in the same manner as in Example 1, except that no cushioning material was provided.

[0062] [Evaluation of SiC chip contamination] For the bonded bodies prepared in (5), surface contamination of the Al anode electrode of the SiC chip, which is the second bonded material of the bonded bodies prepared in the examples and comparative examples, was evaluated using EDX. The EDX evaluation conditions are as follows. • Measurement device name: JSM-F100 (manufactured by JEOL Ltd.) • Incident voltage: 5kV Magnification: ×75 • WD: 10mm • Live performance time: 240 seconds • Vacuum mode: HV Under the conditions described above, EDX evaluation was performed at four locations on the Al anode electrode of each laminate. There was no overlap in the measurement areas at the four locations. Using the qualitative analysis spectral mode, the F / Al (Atom% ratio) was calculated using the Atom% values ​​obtained from the intensity of the F (fluorine) K line and Al (aluminum) K line at each of the four locations. Subsequently, the average value of the four locations was calculated. A larger F / Al value indicates a greater amount of buffer material (PTFE) adhering to the substrate. Comparative Example 1 did not have a metal material to prevent adhesion, resulting in 1.2 × 10 -2 As a result, the presence of cushioning material was confirmed.

[0063] [Assessment of overall bonding ability] The bondability of the four bonded bodies prepared in (6) was evaluated by measuring the die shear strength using a bond tester. The die shear strength measurement conditions are as follows. ·Measuring device name: Condor Sigma (manufactured by XYZTEC) • Load cell: 200 kgf • Shearing tool: Width 6.0mm, Thickness 2.0mm, Shaft 1 / 4" (Model number: T0S663060) • Share speed: 50 μm / s • Share height: 0.02mm (The zero point is the top of the printed coating, which is 6.0mm square) The joint strength (MPa) was defined as the force (N) at which the second joined material fractured divided by the joint area (area of ​​the second joined material: 24.3 mm²). If the material did not fracture even when a force of 1459 N was applied, the joint strength was considered to be >60 MPa. For those where all four joint strengths were >60 MPa, we determined that the overall joint performance was superior. Comparative Example 2 did not use a buffer material that is effective in ensuring consistent bonding when manufacturing multiple joints simultaneously. As a result, there was variation in bonding strength, with three joints reaching >60 MPa and one joint reaching 8.6 MPa, resulting in poor consistent bonding performance.

[0064] [Presence or absence of scratches on the SiC chip] For the bonded bodies prepared in (5), the degree of scratches on the Al anode electrode of the SiC chip, which is the second bonded material of the bonded bodies prepared in the examples and comparative examples, was confirmed by the arithmetic mean roughness Sa measured in accordance with ISO 25178. The measurement conditions for the arithmetic mean roughness Sa are as follows. ·Measuring device name: Zegage Pro (manufactured by Zygo Corporation) Objective lens magnification: ×1.4 • Zoom lens: ×1.0 After acquiring surface shape data on the SiC chip, the Al anode electrode region was selected using masking (3.5 mm square) to specify the analysis area, and the arithmetic mean roughness Sa was obtained. In Comparative Example 2, no cushioning material was used, resulting in a thickness of 0.801 μm, indicating that the SiC chip was damaged by pressure bonding.

[0065] [Table 1]

[0066] As is clear from Table 1, in the example's bonded structure, the amount of PTFE adhering to the SiC chip, which is the second material to be bonded, is less than in the comparative example, and the SiC chip is less contaminated. Furthermore, the example also shows superior single-piece bonding performance. [Explanation of Symbols]

[0067] 11 First material to be joined 12X membrane body 12 Bonding layer 13 Second material to be joined 15 Laminate 16 Pressing jig 17 Metal materials 18 Cushioning material

Claims

1. A method for manufacturing a joined body in which a first joined material and a second joined material are joined together, The steps include: arranging a film on the first material to be bonded, A step of placing the second material to be joined on the film to form a laminate, The process includes the step of arranging a pressing jig on the end face in the stacking direction of the laminate, Prior to heating and pressurizing the laminate using the pressing jig to join the first to be joined and the second to be joined, a metal material is placed on the laminate, and a cushioning material is placed on the metal material. A method for manufacturing a joint, A method for manufacturing a bonded body, wherein the thickness of the cushioning material is 20 μm or more and 400 μm or less.

2. The method for manufacturing a jointed body according to claim 1, wherein the metal material is a metal or alloy having an elastic modulus of 250 GPa or less.

3. The method for manufacturing a bonded body according to claim 1 or 2, wherein the cushioning material consists of at least one selected from the group consisting of fluororesin, silicone resin, and carbon fiber.

4. The method for manufacturing a bonded body according to claim 1 or 2, wherein the thickness of the metal material is 0.01 μm or more and 200 μm or less.

5. A method for manufacturing a bonded body according to claim 1 or 2, wherein the arithmetic mean roughness Sa of the surface of the metal material facing the laminate, measured in accordance with ISO 25178, is 400 μm or less.

6. A method for manufacturing a bonded body according to claim 1 or 2, wherein the first material to be bonded is a substrate and the second material to be bonded is a semiconductor element.

7. The method for manufacturing a bonded body according to claim 1 or 2, wherein the film body is a sintering precursor containing metal fine particles.

8. The method for producing a bonded body according to claim 7, wherein the sintering precursor containing the metal fine particles comprises particles of copper, silver, palladium, zinc, aluminum, gold, or nickel, or mixtures thereof or alloys thereof, as the metal fine particles.

9. When manufacturing a joined body by preparing a laminate in which a first material to be joined, a film, and a second material to be joined are stacked in this order, a pressing jig is placed on the end face of the laminate in the stacking direction, a cushioning material is placed between the laminate and the pressing jig, and the first material to be joined and the second material to be joined are joined while the laminate is heated and pressurized using the pressing jig, A method for preventing adhesion of a cushioning material, comprising arranging a metal material between the laminate and the cushioning material to prevent the cushioning material from adhering to the joint, A method for preventing adhesion of a cushioning material, wherein the thickness of the cushioning material is 20 μm or more and 400 μm or less.

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