KR102354209B1 - Bonding material and bonding method using the same - Google Patents

Abstract

It is easy to print on a metal substrate such as a copper substrate, and it prevents voids from forming in the metal bonding layer or at the interface between the metal bonding layer and the Si chip or copper substrate without performing preliminary firing when bonding the Si chip to the metal substrate. A bonding material capable of bonding and a bonding method using the bonding material are provided. A bonding material comprising metal particles, a metal paste containing a solvent and a dispersant, wherein the metal particles include first metal particles (small particles) having an average primary particle diameter of 1 to 40 nm, and an average primary particle diameter of 41 to 110 It contains the 2nd metal particle (heavy particle) of nanometer, and the 3rd metal particle (large particle) with an average primary particle diameter of 120 nm - 10 micrometers, The 1st metal particle is 1.4 with respect to a total of 100 mass % of metal particles. to 49 mass %, the second metal particle is 36 mass % or less, the third metal particle is 50 to 95 mass %, and the ratio of the mass of the first metal particle to the mass of the second metal particle is 14/36 do more than

Description

Bonding material and bonding method using the same

The present invention relates to a bonding material and a bonding method using the same, particularly a bonding material containing a metal paste containing metal particles such as silver fine particles, and electronic components such as Si chips on a metal substrate such as a copper substrate using the bonding material It relates to a method of joining.

In recent years, it has been proposed to use a metal paste containing metal particles such as silver fine particles as a bonding material, and to sinter a metal such as silver in the bonding material by heating with the bonding material interposed between the materials to be joined, thereby joining the objects to be joined. There is (for example, refer patent documents 1 - 3).

When using such a bonding material to fix an electronic component such as a Si chip on a metal substrate such as a copper substrate, a metal paste in which metal particles such as silver fine particles are dispersed in a solvent is applied on the substrate and then heated to remove the solvent By doing so, a pre-dried film is formed on the substrate, the electronic component is placed on the pre-dried film, and then the electronic component is heated while applying pressure, whereby the electronic component can be bonded to the substrate through the metal bonding layer.

Japanese Patent Laid-Open No. 2011-80147 (paragraph 0014-0020) Japanese Patent Laid-Open No. 2011-21255 (paragraph 0032-0042) Japanese Patent Publication No. 5976684 (paragraph 0014-0022)

However, the bonding materials of Patent Documents 1 and 2 can be satisfactorily bonded when used for bonding copper substrates or a copper substrate and a copper chip, but are used when bonding a Si chip to a metal substrate such as a copper substrate. On the other hand, voids may occur in the metal bonding layer or at the interface between the metal bonding layer and the Si chip or the copper substrate, and bonding may not be performed satisfactorily. In addition, the bonding material of Patent Documents 1 and 2 has too high a viscosity, so that it may not be able to be printed satisfactorily by a predetermined printing method as in the case of printing on a substrate by inkjet printing or the like. In addition, the bonding material of Patent Document 3, when bonding the Si chip to a metal substrate such as a copper substrate, is applied on the metal substrate and then subjected to preliminary firing to volatilize a certain amount of solvent to form a preliminary drying film, and this preliminary firing If the Si chip is not placed on the film formation and main firing is not performed, voids may be generated in the metal bonding layer or the like, and bonding may not be performed satisfactorily.

Therefore, in view of these conventional problems, the present invention is easy to print on a metal substrate such as a copper substrate, and when bonding a Si chip to a metal substrate, even if preliminary firing is not performed, in the metal bonding layer or between the metal bonding layer and the Si chip. An object of the present invention is to provide a bonding material and a bonding method using the same, which can prevent voids from forming at the interface with a copper substrate and can be bonded well.

As a result of intensive research to solve the above problems, the present inventors have found that, in a bonding material comprising metal particles and a metal paste containing a solvent and a dispersant, as the metal particles, the first metal having an average primary particle diameter of 1 to 40 nm Using the particles, the second metal particles having an average primary particle diameter of 41 to 110 nm, and the third metal particles having an average primary particle diameter of 120 nm to 10 μm, the first 1.4 to 49 mass % of the metal particles, 36 mass % or less of the second metal particles, and 50 to 95 mass % of the third metal particles, the ratio of the mass of the first metal particles to the mass of the second metal particles It has been found that, by making is 14/36 or more, it is possible to provide a bonding material capable of easily printing on a metal substrate such as a copper substrate and satisfactorily bonding a Si chip to a metal substrate, and a bonding method using the same, and the present invention came to completion.

That is, the bonding material according to the present invention is a bonding material comprising metal particles, a metal paste containing a solvent and a dispersant, wherein the metal particles include first metal particles having an average primary particle diameter of 1 to 40 nm, and an average primary The second metal particles having a particle diameter of 41 to 110 nm and the third metal particles having an average primary particle diameter of 120 nm to 10 μm are included, and the first metal particles are contained in an amount of 1.4 to 49 with respect to a total of 100% by mass of the metal particles. mass%, the second metal particle is 36% by mass or less, the third metal particle is contained in a ratio of 50 to 95% by mass, and the ratio of the mass of the first metal particle to the mass of the second metal particle is 14/36 or more characterized.

In this bonding material, it is preferable that the first metal particles are coated with an organic compound having 8 or less carbon atoms, and it is preferable that the second metal particles are coated with an organic compound having 8 or less carbon atoms. Further, the second metal particles are coated with an organic compound having 8 or less carbon atoms, the third metal particles are coated with an organic compound having 9 or more carbon atoms, and the ratio of the mass of the first metal particles to 100% by mass of the total of the metal particles is 1.4 to It is preferable that it is 25 mass %. In these cases, it is preferable that a C8 or less organic compound is a C1-C6 saturated fatty acid or an unsaturated fatty acid, and it is preferable that it is hexanoic acid or sorbic acid. Moreover, it is preferable that the ratio of the mass of the 2nd metal particle with respect to a total of 100 mass % of a metal particle is 2-17 mass %. Further, it is preferable that the solvent is a polar solvent, and the polar solvent is at least one of 1-decanol, 1-dodecanol, 2-ethyl 1,3-hexanediol and 2-methyl-butane-1,3,4-triol. It is preferable that it is 1 or more types. Moreover, it is preferable that a dispersing agent is at least 1 or more types of a carboxylic acid type dispersing agent and a phosphoric acid ester type dispersing agent. Moreover, it is preferable that content of the total of the metal particles in a bonding material is 87-97 mass %. Moreover, it is preferable that a metal particle is a gold particle, a silver particle, a copper particle, or a nickel particle, It is more preferable that it is a silver particle or a copper particle, It is most preferable that it is a silver particle.

Further, the bonding method according to the present invention is characterized in that the bonding material is interposed between the objects to be joined and heated to sinter the metal in the bonding material to form a metal bonding layer, and the objects to be joined are joined by the metal bonding layer. do it with

Further, in the method for manufacturing a bonding material according to the present invention, in the method for manufacturing a bonding material comprising metal particles, a metal paste containing a solvent and a dispersing agent, the first metal particles having an average primary particle diameter of 1 to 40 nm and an average To prepare metal particles comprising a second metal particle having a primary particle diameter of 41 to 110 nm and a third metal particle having an average primary particle diameter of 120 nm to 10 μm, with respect to a total of 100% by mass of the metal particles, The first metal particles are 1.4 to 49 mass %, the second metal particles are 36 mass % or less, and the third metal particles are 50 to 95 mass %, and the mass of the first metal particles with respect to the mass of the second metal particles. It is characterized by kneading this metal particle, a solvent, and a dispersing agent with the ratio of 14/36 or more.

In this bonding material manufacturing method, the second metal particles are coated with an organic compound having 8 or less carbon atoms, the third metal particles are coated with an organic compound having 9 or more carbon atoms, and the amount of the first metal particles with respect to a total of 100% by mass of the metal particles It is preferable to make the ratio of mass into 1.4-25 mass %. Moreover, it is preferable that the ratio of the mass of the 2nd metal particle with respect to a total of 100 mass % of a metal particle shall be 2-17 mass %. Moreover, it is preferable that the solvent is a polar solvent.

In addition, in this specification, "average primary particle diameter of metal particles" means the average value of primary particle diameters obtained from transmission electron micrograph (TEM image) or scanning electron micrograph (SEM image) of metal particles. it means.

According to the present invention, it is easy to print on a metal substrate such as a copper substrate, and when the Si chip is bonded to the metal substrate, voids are generated in the metal bonding layer or at the interface between the metal bonding layer and the Si chip or copper substrate without performing preliminary firing. It is possible to provide a bonding material and a bonding method using the same, which can be prevented from occurring and can be bonded satisfactorily.

BRIEF DESCRIPTION OF THE DRAWINGS The ratio (mass %) of the mass of a 1st metal particle (small particle A), a 2nd metal particle (heavy particle B), and a 3rd metal particle (large particle C) in embodiment of the bonding material by this invention. It is a diagram showing the range in triangular coordinates.

In an embodiment of the bonding material according to the present invention, in the bonding material comprising metal particles and a metal paste containing a solvent and a dispersing agent, the metal particles include first metal particles having an average primary particle diameter of 1 to 40 nm and an average of 1 Second metal particles having a primary particle diameter of 41 to 110 nm and third metal particles having an average primary particle diameter of 120 nm to 10 μm are included, and the first metal particles are contained in an amount of 1.4 to 100% by mass of the total of the metal particles. 49 mass %, the second metal particle is 36 mass % or less, and the third metal particle is 50 to 95 mass %, and the ratio of the mass of the first metal particle to the mass of the second metal particle (the first metal particle) The mass/mass of the second metal particle) of 14/36 or more.

That is, in the embodiment of the bonding material according to the present invention, as shown in FIG. 1 , the mass of the first metal particle (small particle A), the second metal particle (heavy particle B), and the third metal particle (large particle C) The ratio (mass %) is the point A (100, 0, 0) which is 100 mass %, 0 mass %, and 0 mass %, respectively, and the point B (0, 100, 0 mass %) which is 0 mass %, 100 mass %, and 0 mass %. 0) and point a(49, 1, 50), point b on the coordinates (triangular coordinates) of triangle ABC with vertices C(0, 0, 100) which are 0 mass%, 0 mass%, 100 mass% (14, 36, 50), point c(1.4, 3.6, 95), point d(5, 0, 95), and point e(49, 0, 51) within the region of the pentagon obtained by connecting straight lines in this order. (including the pentagonal line). In addition, in the triangular coordinates of FIG. 1 , the straight line bC is the ratio of the mass of the first metal particle to the mass of the second metal particle (heavy particle B) (except for the point C) (the mass of the first metal particle / the second The case where the metal particle mass) is 14/36 is shown.

In addition, the ratio (mass %) of the mass of the 1st metal particle (small particle A), the 2nd metal particle (heavy particle B), and the 3rd metal particle (large particle C) is 100 mass % of a total of metal particles, It is preferable that the ratio of the first metal particles is 2 to 40 mass%, the second metal particles are 32 mass% or less, and the third metal particles are 50 to 95 mass%, the first metal particles are 2.5 to 30 mass%, It is more preferable to make the 2nd metal particle into 29 mass % or less, and to make the 3rd metal particle into the ratio of 50-95 mass %. In particular, when the bonding material is used for bonding the Si chip and the metal substrate, the ratio of the mass of the first metal particles to the total of 100% by mass of the metal particles in order to reduce the viscosity of the bonding material to facilitate printing on the metal substrate. It is preferable to set it as 1.4-25 mass %. In addition, when the bonding material is used for bonding the Si chip and the metal substrate, in order to properly bond the Si chip, the ratio of the mass of the second metal particles to the total of 100% by mass of the metal particles is 17% by mass or less. Preferably, in order to reduce the viscosity of the bonding material to facilitate printing on the metal substrate, it is more preferable that the ratio of the mass of the second metal particles to the total of 100% by mass of the metal particles is 2 to 17% by mass.

The average primary particle diameter of the first metal particles (small particles) is 1 to 40 nm, and in order to prevent voids from forming when the bonding material is used for bonding the Si chip and the metal substrate, and for good bonding, 5 to It is preferable that it is 30 nm, and it is more preferable that it is 10-20 nm. The average primary particle diameter of the second metal particles (heavy particles) is 41 to 110 nm, and when the bonding material is used for bonding the Si chip and the metal substrate, it is easy to print on the metal substrate and in order to bond the Si chip well. , It is preferable that it is 50-105 nm, and it is more preferable that it is 55-100 nm. Since these first metal particles (small particles) and second metal particles (heavy particles) have a small particle diameter and are easy to aggregate, it is preferable that they are each coated with an organic compound having 8 or less carbon atoms (preferably different organic compounds). . The organic compound is preferably a saturated fatty acid or unsaturated fatty acid having 1 to 6 carbon atoms, more preferably hexanoic acid or sorbic acid. In addition, the average primary particle diameter of the third metal particles (large particles) is 120 nm to 10 μm, and when the bonding material is used for bonding the Si chip and the metal substrate, in order to facilitate printing on the metal substrate, 0.2 to It is preferable that it is 5 micrometers, and it is more preferable that it is 0.3-3 micrometers. The third metal particles (large particles) may be coated with an organic compound (such as a fatty acid or an amine). In particular, when the bonding material is used for bonding the Si chip and the metal substrate, the ratio of the mass of the first metal particles to the total of 100% by mass of the metal particles in order to reduce the viscosity of the bonding material to facilitate printing on the metal substrate. It is preferable to be 1.4-25 mass % and to coat|cover the 3rd metal particle with a C9 or more organic compound while coat|covering a 2nd metal particle with a C8 or less organic compound. In this way, by making the carbon number of the organic compound covering the third metal particles greater than the carbon number of the organic compound covering the second metal particles (the main chain in the molecule of the organic compound is lengthened), the first metal without adding the second metal particles Compared to the case where the particles and the third metal particles are added, the viscosity of the bonding material can be lowered. Examples of such organic compounds having 9 or more carbon atoms include lauric acid, stearic acid, palmitic acid, oleic acid, linoleic acid, linolenic acid, laurylamine, undecylamine, and dodecylamine having 9 to 20 carbon atoms (such as carboxylic acid) Fatty acids, amines, etc. can be used, but in order to lower the viscosity of the bonding material, it is preferable to use an amine or carboxylic acid having 12 to 20 carbon atoms, more preferably an amine or carboxylic acid having 14 to 18 carbon atoms. . Further, the metal particles are preferably gold particles, silver particles, copper particles or nickel particles (in order to properly bond the Si chip when the bonding material is used for bonding the Si chip and the metal substrate), and (conductivity of the bonding material) It is more preferable that they are silver particles or copper particles (to improve the oxidation resistance of the bonding material), and silver particles are most preferable (to improve the oxidation resistance of the bonding material). The total content of the metal particles in the bonding material is preferably 87 to 97% by mass, and 90 to 95% by mass (for satisfactory bonding of the Si chip when the bonding material is used for bonding between the Si chip and the metal substrate). It is more preferable that

The average primary particle diameter of the metal particles is, for example, a transmission electron microscope (TEM) (JEM-1011 manufactured by Nippon Electronics Co., Ltd.) or a scanning electron microscope (SEM) (Hitachi High Technologies) of the metal particles. Primary particle diameter (diameter of a circle corresponding to a circle with the same area) of 100 or more arbitrary metal particles on an image (SEM image or TEM image) observed at a predetermined magnification with S-4700 manufactured by Corporation can be calculated from Calculation of the average primary particle diameter (number average) of this metal particle can be performed, for example by image analysis software (A phase group (trademark) manufactured by Asahi Chemical Engineering Co., Ltd.).

The content of the solvent in the metal paste is preferably 1 to 10% by mass (in order to obtain a metal paste having a viscosity in which metal particles can form a metal bonding layer by sintering and easy to print on a metal substrate), and 2 to It is more preferable that it is 8 mass %. As this solvent, various polar solvents (dispersion medium) can be used. For example, as a polar solvent, water, alcohol, polyol, glycol ether, 1-methylpyrrolidinone, pyridine, terpineol, butylcarbitol, butylcarbitol acetate, texanol, phenoxypropanol, diethylene glycol mono Butyl ether, diethylene glycol monobutyl ether acetate, γ-butyrolactone, ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, methoxybutyl acetate, methoxypropyl acetate, diethylene glycol monoethyl ether acetate, lactic acid Ethyl, 1-octanol, and the like can be used. As such a polar solvent, 1-decanol, 1-dodecanol, 1-tetradecanol, 3-methyl-1,3-butanediol 3-hydroxy-3-methylbutyl acetate, 2-ethyl-1,3-hexane Diol, hexyldiglycol, 2-ethylhexylglycol, dibutyldiglycol, glycerin, dihydroxyterpineol, dihydroterpinylacetate, 2-methyl-butane-2,3,4-triol (isopretriol A (IPTL-A, manufactured by Nippon Terpene Chemical Co., Ltd.), 2-methyl-butane-1,3,4-triol (isopretriol B (IPTL-B, manufactured by Nippon Terpene Chemical), Tersolve IPG-2Ac (manufactured by Nippon Terpene Chemicals), Tersolve MTPH (manufactured by Nippon Terpene Chemicals), Tersolve DTO-210 (manufactured by Nippon Terpene Chemicals), Tersolve THA- 90 (Nippon Terpene Chemical Co., Ltd.) Tersolv THA-70 (Nippon Terpene Chemical Co., Ltd.) Tersolv TOE-100 (Nippon Terpene Chemical Co., Ltd.), dihydroterpinyloxyethanol (Nippon Terpene Chemical Co., Ltd.), terpinyl methyl ether (Nippon Terpene Chemical Co., Ltd.), dihydroterpinyl methyl ether (Nippon Terpene Chemical Co., Ltd.), etc. are preferably used; At least one of 1-decanol, 1-dodecanol, 2-ethyl 1,3-hexanediol and 2-methyl-butane-1,3,4-triol (isopretriol B (IPTL-B)) It is more preferable to use

It is preferable that it is 0.01-2 mass %, and, as for content of the dispersing agent in a metal paste, it is more preferable that it is 0.03-0.7 mass %. As this dispersing agent, various commercially available dispersing agents can be used. For example, Sanyo Chemical Co., Ltd. Beurite LCA-H, LCA-25NH, Kyoesha Chemical Co., Ltd. Floren DOPA-15B, Nippon Lubrizol Co., Ltd. Brush Plus AX5, Sol Sparse 9000, Sol Six 250, EFKA 4008 by EFKA Additives, Ajisper PA111 by Ajinomoto Fine Techno, Co., Ltd. TEXAPHOR-UV21 by Cognis Japan, Big Chemi Japan Co., Ltd. DisperBYK2020, BYK220S made by Kaisha, Dispalon 1751N made by Kusumoto Chemicals, Hip Rad ED-152, FTX-207S made by Neos, Ftergent 212P, AS-1100 made by Toagosei Co., Ltd. , Gao Cera 2000, KDH-154, MX-2045L, made by Kao Corporation, Homogenol L-18, Leodol SP-010V, Epan U103, Cyanol DC902B, Neugen manufactured by Daiichi Kogyo Seiyaku Co., Ltd. EA-167, Flysurf A219B, Megapack F-477 manufactured by DIC Corporation, Silface SAG503A manufactured by Nisshin Chemical Co., Ltd., Dinol 604, SN Spaz 2180 manufactured by Sannofco Corporation, SN Leveler S-906, AGC Seimi Chemical S-386, Nippon Lubrizol Corporation Sol Plus D540, Sol Sparse 44000, Sol Sparse 43000, Sol Sparse 20000, Sol Sparse 27000, CRODA Cirrasol G-265, Hypermer KD1, Hypermer KD2, Hypermer KD3, Hypermer KD4, Hypermer KD9, Hypermer KD11, Hypermer KD12, Hypermer KD16, Hypermer KD57, Armer163, CRODA Synperoic T701, Zephrym PD2246SF, Zephrym 3300B manufactured by CRODA. Sunspearl PS-2 made by Corporation, Carribon L400, DisperBYK made by Big Chemie Japan Corporation 2055, DisperBYK2155, DisperBYK2055, DisperBYK193, BYKP105, BYKPR606, DisperBYK2013, DisperBYK108, DisperBYK109, DisperBYK145, DisperBYK2008, DisperBYK2096, DisperBYK2152, BYK-LPC22145, BYK-LPC22125, etc. It is preferable that it is at least 1 sort(s) or more of a carboxylic acid type dispersing agent, such as oxyacetic acid, and a phosphoric acid ester type dispersing agent.

The viscosity of the metal paste is preferably 5 to 2500 Pa·s, more preferably 5 to 1000 Pa·s, and most preferably 10 to 500 Pa·s, measured at ^{2s −1 at 25° C.,} The ^{viscosity measured at 20s -1} is preferably 1 to 150 Pa·s, more preferably 1 to 100 Pa·s, and most preferably 2 to 35 Pa·s.

In an embodiment of the method for manufacturing a bonding material according to the present invention, in the method for manufacturing a bonding material comprising metal particles, a metal paste containing a solvent and a dispersant, the first metal particles having an average primary particle diameter of 1 to 40 nm; Metal particles containing second metal particles having an average primary particle diameter of 41 to 110 nm and third metal particles having an average primary particle diameter of 120 nm to 10 μm are prepared, and the total amount of the metal particles is 100% by mass. , 1.4 to 49 mass % of the first metal particle, 36 mass % or less of the second metal particle, and 50 to 95 mass % of the third metal particle, and the amount of the first metal particle with respect to the mass of the second metal particle The mass ratio is set to 14/36 or more, and this metal particle, a solvent, and a dispersing agent are knead|mixed.

In an embodiment of the bonding method according to the present invention, the bonding material is applied between the objects to be joined, for example, a Si chip (where the bonding surface of the metal substrate is silver-plated or gold-plated) and (the bonding surface of the Si chip is silver-plated or gold-plated) A metal bonding layer is formed by sintering a metal such as silver in a bonding material by interposing it with a metal substrate (such as a copper substrate or a copper substrate without copper substrate) and heating, and the metal bonding layer allows the objects to be joined (e.g. For example, a Si chip and a metal substrate) are bonded.

Specifically, the bonding material is applied (by printing, etc.) to at least one of the two to-be-joined objects, and the bonding material is arrange|positioned so that it may interpose between the to-be-joined objects, By heating at 210-400 degreeC, preferably 210-300 degreeC, The metal in the metal paste is sintered to form a metal bonding layer, and the to-be-joined objects can be joined by this metal bonding layer. Further, a bonding material is applied to one side of the two to-be-joined objects, and the bonding material is dried by heating at 60-200 degreeC, preferably 80-170 degreeC, and a pre-drying film is formed, and the other to-be-joined material is formed on this pre-dried film|membrane. After mounting, by heating at 210 to 400° C., preferably 210 to 300° C., the metal in the metal paste is sintered to form a metal bonding layer, and the to-be-joined objects may be joined by this metal bonding layer. In addition, at the time of heating, although it is not necessary to apply pressure between to-be-joined objects, you may apply pressure. Moreover, even if it heats in inert atmosphere, such as nitrogen atmosphere, although to-be-joined objects can be joined, even if it heats in air, to-be-joined objects can be joined.

When the embodiment of the bonding material described above is used for bonding a Si chip and a metal substrate such as a copper substrate, printing on the metal substrate is easy, and even without preliminary firing, the inside of the metal bonding layer or the interface between the metal bonding layer and the Si chip or copper substrate It is possible to prevent voids from forming on the surface and to ensure good bonding. In particular, good even if the area of the bonding surface between the Si chip and the metal substrate is large (in the case where the area of the bonding surface is preferably 25 mm 2 or less, more preferably 1 to 25 mm 2 , and most preferably 4 to 25 mm 2 ) can be tightly joined.

Example

Hereinafter, the bonding material by this invention and the Example of the bonding method using the same are demonstrated in detail.

[Example 1]

3400 g of water was put into a 5 L reactor, and dissolved oxygen was removed by flowing nitrogen at a flow rate of 3000 mL/min from a nozzle installed at the bottom of the reactor for 600 seconds into the water in the reactor, and then nitrogen at a flow rate of 3000 mL/min from the top of the reactor. was supplied into the reaction tank to make the inside of the reaction tank a nitrogen atmosphere, and while stirring with a stirring bar having a stirring blade installed in the reaction tank, the temperature of the water in the reaction tank was adjusted to 60°C. After adding 7 g of ammonia water containing 28 mass % ammonia to the water in this reaction tank, it stirred for 1 minute and set it as the uniform solution. 45.5 g (molar ratio to silver 1.98) of hexanoic acid (manufactured by Wako Pure Chemical Industries, Ltd.), which is a saturated fatty acid (manufactured by Wako Pure Chemical Industries, Ltd.), was added to the solution in this reaction tank as an organic compound, stirred for 4 minutes to dissolve, and then 50% by mass of hydrazine as a reducing agent 23.9 g (4.82 equivalents with respect to silver) of a hydrate (made by Otsuka Chemical Co., Ltd.) was added, and it was set as the reducing agent solution.

Further, an aqueous silver nitrate solution obtained by dissolving 33.8 g of silver nitrate crystals (manufactured by Wako Pure Chemical Industries, Ltd.) in 180 g of water was prepared as a silver salt aqueous solution, the temperature of the silver salt aqueous solution was adjusted to 60° C. Copper nitrate trihydrate (manufactured by Wako Pure Chemical Industries, Ltd.) 0.00008 g (1 ppm in terms of copper with respect to silver) was added. In addition, addition of copper nitrate trihydrate was performed by adding the aqueous solution which diluted the aqueous solution of copper nitrate trihydrate of high concentration to some extent so that it might become the addition amount of copper of the objective.

Then, the silver salt aqueous solution was added to the reducing agent solution at once, mixed, and the reduction reaction was started while stirring. In about 10 seconds from the start of the reduction reaction, the color change of the slurry as the reaction solution is completed, and after aging for 10 minutes while stirring, the stirring is terminated, the solid-liquid separation is performed by suction filtration, and the obtained solid is washed with pure water, , and vacuum-dried at 40°C for 12 hours to obtain a dry powder of silver fine particles (silver nanoparticles) (coated with hexanoic acid). In addition, as for the ratio of silver in this silver microparticles|fine-particles, it computed that it was 97 mass % from the weight after removing hexanoic acid by heating. Moreover, when the average primary particle diameter of this silver fine particle was calculated|required with the transmission electron microscope (TEM), it was 17 nm.

Furthermore, 180.0 g of pure water was put into a 300 mL beaker, and silver nitrate aqueous solution was manufactured as a raw material liquid by adding and dissolving 33.6 g of silver nitrate (made by Toyo Chemical Corporation).

Furthermore, 3322.0 g of pure water was put into a 5 L beaker, and nitrogen was vented in this pure water for 30 minutes to remove dissolved oxygen, and the temperature was raised to 40°C. To this pure water (for coating silver fine particles), 44.8 g of sorbic acid (manufactured by Wako Pure Chemical Industries, Ltd.) as an organic compound was added, followed by 7.1 g of 28% aqueous ammonia as a stabilizer (manufactured by Wako Pure Chemical Industries, Ltd.) was added

While stirring the aqueous solution after adding this aqueous ammonia, after 5 minutes from the time of addition of the aqueous ammonia (at the start of the reaction), 14.91 g of 80% pure hydrous hydrazine (manufactured by Otsuka Chemical Co., Ltd.) as a reducing agent is added and reduced A reducing agent-containing aqueous solution was prepared as a liquid. After 9 minutes from the start of the reaction, the raw material solution (silver nitrate aqueous solution) whose liquid temperature is adjusted to 40°C is added to the reducing solution (reducing agent-containing aqueous solution) at once and reacted, stirred for another 80 minutes, and then the temperature rise rate is 1 The liquid temperature was raised from 40°C to 60°C at a rate of °C/min to complete stirring.

After forming the aggregates of silver fine particles (silver nanoparticles) coated with sorbic acid in this way, the liquid containing the aggregates of the silver fine particles is filtered with No. 5C filter paper, and the recovered product by this filtration is purified water It wash|cleaned and obtained the aggregate of silver microparticles|fine-particles. The aggregate of this silver microparticles|fine-particles was dried at 80 degreeC in a vacuum dryer for 12 hours, and the dry powder of the aggregate of silver microparticles|fine-particles was obtained. Thus, the dry powder of the aggregate of the obtained silver fine particles was pulverized, and the magnitude|size of the secondary aggregate was adjusted. Moreover, it was 85 nm when the average primary particle diameter of this silver fine particle was calculated|required with the scanning electron microscope (SEM).

Next, 14.5 g of dry powder (first silver particles (small particles)) of silver fine particles (coated with hexanoic acid) having an average primary particle diameter of 17 nm and an average primary particle diameter of 85 nm (with sorbic acid) 7.5 g of dry powder (second silver particles (heavy particles)) of silver particles (coated) and micrometer size (with an average primary particle diameter of 0.3 μm as determined by SEM image) as third silver particles (large particles) of (coated with oleic acid) silver particles (AG2-1C manufactured by DOWA Electronics Co., Ltd.) 70 g and butoxyethoxyacetic acid (BEA) (manufactured by Tokyo Kasei Kogyo Co., Ltd.) as a first dispersant (carboxylic acid dispersant) 0.5 g and 0.05 g of a phosphate ester-based dispersant (SOLPLUS D540 manufactured by Lubrizol) as a second dispersing agent, 2.45 g of 1-decanol (manufactured by Wako Pure Chemical Industries, Ltd.) as a first solvent, and octanediol ( 1.5 g of 2-ethyl-1,3-hexanediol manufactured by Kyowa Hakko Chemical Co., Ltd.) and 2-methyl-butane-1,3,4-triol (isoprenetriol B (IPTL-) as a third solvent B)) (manufactured by Nippon Terpene Chemical Co., Ltd.) 3.5 g was kneaded, and the resulting kneaded product was passed through a triaxial roll to obtain a bonding material containing silver paste. In addition, in this bonding material (silver paste), the total content of the first silver particles, the second silver particles, and the third silver particles is 92 mass %, and the mass ratio of the first silver particles, the second silver particles, and the third silver particles ( first silver particle:second silver particle:third silver particle) is 16:8:76.

The viscosity of this bonding material (silver paste) was determined with a rheometer (viscoelasticity measuring device) (using a HAAKE RheoStress 600 manufactured by Thermo Corporation, a cone having a cone diameter of 35 mm and a cone angle of 2°), and was found to be 2s ^{-1 at 25°C.} 309 (Pa s) at 309 (Pa s), 20s ^-1 to 26 (Pa s), and the ratio of the viscosity of 2s ^{-1 to the viscosity of 20s -1 measured at 25°C (the viscosity of 2s -1} / the viscosity of 20s ^-1 ) ) (thix ratio) Ti was 11.7, and the printability (printability) of the bonding material (silver paste) was good.

In addition, while preparing a copper substrate and a substrate plated with silver on one side (surface to become a bonding surface) of this copper substrate, (the surface to become a bonding surface) with silver Prepare two plated Si chips, place a 50 µm thick metal mask on each substrate, and apply the bonding material (silver paste) with a metal squeegee to the same size as the area of the back surface of the Si chip and 50 µm thick After coating on each substrate so as to become sintering was performed to sinter the silver in the silver paste to form a silver bonding layer, and the Si chip was bonded to each substrate by the silver bonding layer.

From the image (C-SAM image) obtained by the ultrasonic microscope (C-SAM) (D9500 manufactured by SONOSCAN) about the two bonded bodies obtained in this way, the silver bonding layer (the inside of the silver bonding layer, a board|substrate, and a Si chip) When the presence or absence of a void in each interface) was observed, a void was not observed in any joined body, and it was joined well. In addition, when the entire surface of the C-SAM phase is black, it is judged that there is no void and good bonding is achieved. It was judged that it was not, and when the whole surface of a C-SAM image was white, there was a void in the whole surface, and it was judged that the bonding state is not favorable (or it is a peeled state).

[Example 2]

The amounts of the first to third silver particles in the bonding material (silver paste) were respectively 14.5 g, 0 g, and 77.5 g (mass ratio of the first silver particle, the second silver particle, and the third silver particle (the first silver particle: the second silver)) A bonding material was prepared in the same manner as in Example 1, except that the particle:third silver particle) was 16:0:84), and the viscosity was determined at 2s ⁻¹ to 712 (Pa) at 25°C. ·s), 20s ⁻¹ to 49 (Pa·s), the thix ratio Ti was 14.6, and the printability (printability) of the bonding material (silver paste) was good. In addition, using the obtained bonding material, two bonded bodies were produced in the same manner as in Example 1, and the presence or absence of voids in the silver bonding layer was observed. there was.

[Example 3]

The amounts of the first to third silver particles in the bonding material (silver paste) were respectively 19.78 g, 0 g, and 72.22 g (mass ratio of the first silver particle, the second silver particle, and the third silver particle (the first silver particle: the second silver)) particles: a third silver particles) to 22: 0: 78) as would be the exception of example 1 and by the method similar to, produce a bonding material, and in the 2s ^-1 in the bar, 25 ℃ determined its viscosity 1034 (㎩ ·s), 20s ⁻¹ to 47 (Pa·s), the thixotropic Ti was 22.0, and the printability (printability) of the bonding material (silver paste) was good. In addition, using the obtained bonding material, two bonded bodies were produced by the same method as in Example 1, and the presence or absence of voids in the silver bonding layer was observed. there was.

[Example 4]

The amounts of the first to third silver particles in the bonding material (silver paste) were respectively 14.5 g, 12.5 g, and 65.0 g (mass ratio of the first silver particle, the second silver particle, and the third silver particle (the first silver particle: the second silver particle) A bonding material was prepared in the same manner as in Example 1, except that the silver particle: the third silver particle) was 16:14:70), and the viscosity was determined at 25° C. at 2s ⁻¹ to 357 ( Pa·s), 20s ⁻¹ to 22 (Pa·s), the thixotropic Ti was 16.0, and the printability (printability) of the bonding material (silver paste) was good. In addition, using the obtained bonding material, two bonded bodies were produced by the same method as in Example 1, and the presence or absence of voids in the silver bonding layer was observed. there was.

[Example 5]

The amounts of the first to third silver particles in the bonding material (silver paste) were respectively 14.75 g, 14.75 g, and 62.5 g (mass ratio of the first silver particle, the second silver particle, and the third silver particle (the first silver particle: the second silver particle) A bonding material was prepared in the same manner as in Example 1, except that the silver particles: the third silver particles) were 16:16:68), and the viscosity was determined at 2s ⁻¹ to 287 ( Pa·s), 20s ⁻¹ to 25 (Pa·s), the thixotropic Ti was 11.6, and the printability (printability) of the bonding material (silver paste) was good. In addition, using the obtained bonding material, two bonded bodies were produced by the same method as in Example 1, and the presence or absence of voids in the silver bonding layer was observed. there was.

[Example 6]

The amounts of the first to third silver particles in the bonding material (silver paste) were respectively 12.5 g, 7.5 g, and 72.0 g (mass ratio of the first silver particle, the second silver particle, and the third silver particle (the first silver particle: the second silver particle) are particles of claim 3 particles) of 14: 8: 78) as would be the exception of example 1 and by the same method to prepare a bonding material, at 2s ^-1 211 in the bar, 25 ℃ determined its viscosity ( Pa·s), 20 s ⁻¹ to 17 (Pa·s), the thixotropy Ti was 12.4, and the printability (printability) of the bonding material (silver paste) was good. In addition, using the obtained bonding material, two bonded bodies were produced by the same method as in Example 1, and the presence or absence of voids in the silver bonding layer was observed. there was.

[Example 7]

The amounts of the first to third silver particles in the bonding material (silver paste) were respectively 7.25 g, 7.25 g, and 77.5 g (mass ratio of the first silver particle, the second silver particle, and the third silver particle (the first silver particle: the second silver particle) A bonding material was prepared in the same manner as in Example 1, except that the silver particles: the third silver particles) were set to 8:8:84), and the viscosity was determined at 2s ⁻¹ to 118 ( Pa·s), 20s ⁻¹ to 15 (Pa·s), the thixotropic Ti was 8.1, and the printability (printability) of the bonding material (silver paste) was good. In addition, using the obtained bonding material, two bonded bodies were produced by the same method as in Example 1, and the presence or absence of voids in the silver bonding layer was observed. there was.

[Example 8]

The amounts of the first to third silver particles in the bonding material (silver paste) were respectively 14.5 g, 26.8 g, and 50.7 g (mass ratio of the first silver particle, the second silver particle, and the third silver particle (the first silver particle: the second silver particle) A bonding material was prepared in the same manner as in Example 1, except that the silver particle: the third silver particle) was 16:29:55), and the viscosity was determined at 2s ⁻¹ to 28 ( Pa·s), 20s ⁻¹ to 9 (Pa·s), the thixotropy Ti was 3.0, and the printability (printability) of the bonding material (silver paste) was good. In addition, using the obtained bonding material, two bonded bodies were produced in the same manner as in Example 1, and the presence or absence of voids in the silver bonding layer was observed. In the bonded body of the silver-plated copper substrate, voids were not observed , but were bonded favorably, in the bonded body of the copper substrate not subjected to silver plating, voids were observed and bonding was not satisfactory.

[Example 9]

The amounts of the first to third silver particles in the bonding material (silver paste) were respectively 14.5 g, 17.5 g, and 60.0 g (mass ratio of the first silver particle, the second silver particle, and the third silver particle (the first silver particle: the second silver particle) A bonding material was prepared in the same manner as in Example 1, except that the silver particle: the third silver particle) was 16:19:65), and the viscosity was determined at 2s ⁻¹ to 96 ( Pa·s), 20 s ⁻¹ to 20 (Pa·s), the thixotropic Ti was 4.8, and the printability (printability) of the bonding material (silver paste) was good. In addition, using the obtained bonding material, two bonded bodies were produced in the same manner as in Example 1, and the presence or absence of voids in the silver bonding layer was observed. In the bonded body of the silver-plated copper substrate, voids were not observed , but were bonded favorably, in the bonded body of the copper substrate not subjected to silver plating, voids were observed and bonding was not satisfactory.

[Example 10]

The amounts of the first to third silver particles in the bonding material (silver paste) were respectively 7.5 g, 9.75 g, and 74.75 g (mass ratio of the first silver particle, the second silver particle, and the third silver particle (the first silver particle: the second silver particle) A bonding material was prepared in the same manner as in Example 1, except that the silver particle: the third silver particle) was set to 8:11:81), and the viscosity was determined at 2s ⁻¹ to 86 ( Pa.s), 20s ^-1 to 13 (Pa·s), the thixotropic Ti was 6.6, and the printability (printability) of the bonding material (silver paste) was good. In addition, using the obtained bonding material, two bonded bodies were produced by the same method as in Example 1, and the presence or absence of voids in the silver bonding layer was observed. there was.

[Example 11]

The amounts of the first to third silver particles in the bonding material (silver paste) were respectively 4.5 g, 7.5 g, and 80.0 g (mass ratio of the first silver particle, the second silver particle, and the third silver particle (the first silver particle: the second silver particle) A bonding material was prepared in the same manner as in Example 1, except that the silver particle: the third silver particle) was set to 5:8:87), and the viscosity was determined at 2s ⁻¹ to 62 ( Pa·s), 20s ⁻¹ to 13 (Pa·s), the thixotropic Ti was 4.7, and the printability (printability) of the bonding material (silver paste) was good. In addition, using the obtained bonding material, two bonded bodies were produced in the same manner as in Example 1, and the presence or absence of voids in the silver bonding layer was observed. there was.

[Example 12]

The amounts of the first to third silver particles in the bonding material (silver paste) were respectively 27.6 g, 0 g, and 64.4 g (mass ratio of the first silver particle, the second silver particle, and the third silver particle (the first silver particle: the second silver)) particles: a third silver particles) to 30: 0: 70) as would be the exception of example 1 and by the method similar to, produce a bonding material, and in the 2s ^-1 was determined according to its viscosity, to 25 ℃ 2135 (㎩ ·s), 20s ⁻¹ to 127 (Pa·s), the thixotropic Ti was 16.9, and the printability (printability) of the bonding material (silver paste) was good. In addition, using the obtained bonding material, two bonded bodies were produced by the same method as in Example 1, and the presence or absence of voids in the silver bonding layer was observed. there was.

[Example 13]

The amounts of the first to third silver particles in the bonding material (silver paste) were respectively 27.6 g, 18.4 g, and 46.0 g (mass ratio of the first silver particle, the second silver particle, and the third silver particle (the first silver particle: the second silver particle) A bonding material was prepared in the same manner as in Example 1, except that the silver particles: the third silver particles) were set to 30:20:50), and the viscosity thereof was determined at 2s ^-1 to 2186 ( Pa·s), 20s ⁻¹ to 96 (Pa·s), the thixotropic Ti was 22.8, and the printability (printability) of the bonding material (silver paste) was good. In addition, using the obtained bonding material, two bonded bodies were produced in the same manner as in Example 1, and the presence or absence of voids in the silver bonding layer was observed. In the bonded body of the silver-plated copper substrate, voids were not observed , but were bonded favorably, in the bonded body of the copper substrate not subjected to silver plating, voids were observed and bonding was not satisfactory.

[Example 14]

The amounts of the first to third silver particles in the bonding material (silver paste) were respectively 2.3 g, 2.3 g, and 87.4 g (mass ratio of the first silver particle, the second silver particle, and the third silver particle (the first silver particle: the second silver particle) A bonding material was prepared in the same manner as in Example 1, except that the silver particle: the third silver particle) was set to 2.5:2.5:95), and the viscosity was determined at 2s ⁻¹ to 37 ( Pa·s), 20s ⁻¹ to 11 (Pa·s), the thixotropic Ti was 3.4, and the printability (printability) of the bonding material (silver paste) was good. In addition, using the obtained bonding material, two bonded bodies were produced by the same method as in Example 1, and the presence or absence of voids in the silver bonding layer was observed. there was.

[Example 15]

As the third silver particles (large particles), instead of the micrometer-sized (coated with oleic acid) silver particles (AG2-1C manufactured by DOWA Electronics) (having an average primary particle diameter of 0.3 µm as determined by SEM image) , except that micrometer-sized (coated with sorbic acid) silver particles (super-fine silver powder-2 manufactured by DOWA Electronics Co., Ltd.) (with an average primary particle diameter determined by SEM image of 0.3 µm) were used. A bonding material was prepared in the same manner as in 1, and the viscosity was determined. At 25°C, 2s ⁻¹ to 826 (Pa·s), 20s ⁻¹ to 69 (Pa·s), and the thixotropic Ti was 12.0. , the printability (printability) of the bonding material (silver paste) was good.

[Comparative Example 1]

The amounts of the first to third silver particles in the bonding material (silver paste) were respectively 4.5 g, 17.5 g, and 70.0 g (mass ratio of the first silver particle, the second silver particle, and the third silver particle (the first silver particle: the second silver particle) A bonding material was prepared in the same manner as in Example 1, except that the silver particle: the third silver particle) was set to 5:19:76), and the viscosity was determined at 2s ⁻¹ to 20 ( Pa·s), 20s ⁻¹ to 8 (Pa·s), the thixotropic Ti was 2.4, and the printability (printability) of the bonding material (silver paste) was good. In addition, using the obtained bonding material, two bonded bodies were produced in the same manner as in Example 1, and the presence or absence of voids in the silver bonding layer was observed. In any of the bonded bodies, voids were observed, and the bonding was not satisfactory. .

[Comparative Example 2]

The amounts of the first to third silver particles in the bonding material (silver paste) were respectively 9.2 g, 27.6 g, and 55.2 g (mass ratio of the first silver particle, the second silver particle, and the third silver particle (the first silver particle: the second silver particle) A bonding material was prepared in the same manner as in Example 1, except that the silver particle: the third silver particle) was 10:30:60), and the viscosity was determined at 2s ⁻¹ to 13 ( Pa·s), 20s ⁻¹ to 7 (Pa·s), the thixotropic Ti was 1.7, and the printability (printability) of the bonding material (silver paste) was good. In addition, using the obtained bonding material, two bonded bodies were produced in the same manner as in Example 1, and the presence or absence of voids in the silver bonding layer was observed. Voids were observed in any of the bonded bodies, and bonding was not satisfactory.

[Comparative Example 3]

The amounts of the first to third silver particles in the bonding material (silver paste) were respectively 27.6 g, 27.6 g, and 36.8 g (mass ratio of the first silver particle, the second silver particle, and the third silver particle (the first silver particle: the second silver particle) A bonding material was prepared in the same manner as in Example 1, except that the silver particle: the third silver particle) was set to 30:30:40), and an attempt was made to obtain the viscosity, but the measurement exceeded the measurement upper limit of the viscosity. It could not be done, and the printability (printability) of the bonding material (silver paste) was not favorable. In addition, using the obtained bonding material, two bonded bodies were produced in the same manner as in Example 1, and the presence or absence of voids in the silver bonding layer was observed. In the bonded body of the silver-plated copper substrate, voids were not observed , but were bonded favorably, in the bonded body of the copper substrate not subjected to silver plating, voids were observed and bonding was not satisfactory.

[Comparative Example 4]

The amounts of the first to third silver particles in the bonding material (silver paste) were respectively 46.0 g, 9.2 g, and 36.8 g (mass ratio of the first silver particle, the second silver particle, and the third silver particle (the first silver particle: the second silver particle) A bonding material was prepared in the same manner as in Example 1, except that the silver particle: the third silver particle) was set to 50:10:40), and an attempt was made to obtain the viscosity, but it was measured exceeding the measurement upper limit of the viscosity. It could not be done, and the printability (printability) of the bonding material (silver paste) was not favorable. In addition, using the obtained bonding material, two bonded bodies were produced in the same manner as in Example 1, and the presence or absence of voids in the silver bonding layer was observed. In the bonded body of the silver-plated copper substrate, voids were not observed , but were bonded favorably, in the bonded body of the copper substrate not subjected to silver plating, voids were observed and bonding was not satisfactory.

Tables 1 to 2 show the manufacturing conditions and characteristics of the bonding materials of these Examples and Comparative Examples. In addition, in Table 1, the case where voids were not observed in any bonded body was ○, the case in which voids were observed in any bonded body was x, and no voids were observed in the silver-plated copper substrate bonded body, but silver plating was performed. The case where a void was observed in the joined body of the copper substrate which is not made is shown by (triangle|delta).

As can be seen from these results, in all of the bonding materials of Examples 1 to 15, 1.4 to 49 mass% of the first silver particles (small particles) and 1.4 to 49 mass% of the second silver particles (heavy particles) with respect to a total of 100 mass% of the silver particles 36 mass % or less, the 3rd silver particle (large particle) is 50-95 mass %, and the ratio of the mass of the 1st silver particle (small particle) to the mass of the 2nd silver particle (heavy particle) is 14/36 or more. However, none of the bonding materials of Comparative Examples 1 to 4 were within this range. That is, in all of the bonding materials of Examples 1 to 15, the ratio (mass %) of the mass of the first silver particle (small particle), the second silver particle (heavy particle), and the third silver particle (large particle) is shown in FIG. 1 . Point a(49, 1, 50), point b(14, 36, 50), point c(1.4, 3.6, 95), point d(5, 0, 95) and point e(49, 0, 51) are in the pentagonal region (including the pentagonal line) obtained by linearly connecting them in this order, but in the bonding materials of Comparative Examples 1 to 4, the mass ratio of small particles, heavy particles, and large particles (mass %) is outside the range of the pentagon.

Further, as shown in Tables 1 and 2, in the case of Examples 8, 9, and 13 in which the mass ratio of the second silver particles (heavy particles) among the silver particles of the bonding material was 19% by mass or more, the silver-plated copper substrate bonded body Although voids were not observed in the case of voids, the mass ratio of the second silver particles (heavy particles) among the silver particles of the bonding material should be less than 19% by mass because voids were observed in the bonded body of the copper substrate not subjected to silver plating. it can be seen that Further, from the comparison between Example 2 and Examples 1, 4, 5, 8 and 9, when the second silver particles (heavy particles) were added to the bonding material, the mass ratio of the third silver particles (large particles) decreased, and the bonding material It can be seen that the viscosity of By such a decrease in the viscosity of the bonding material, the printability of the bonding material is improved, and the handling of the bonding material is also improved. Therefore, it is preferable to add a 2nd silver particle (heavy particle) in a bonding material. Further, from the comparison between Example 12 and Example 13, when the mass ratio of the first silver particles (small particles) among the silver particles of the bonding material becomes 30% by mass, even if the second silver particles (heavy particles) are added to the bonding material, the bonding material It can be seen that the viscosity does not decrease. Further, from the comparison between Example 1 and Example 15, as in Example 15, when the second silver particles (heavy particles) and the third silver particles (large particles) were coated with an organic compound (sorbic acid having 6 carbon atoms) having the same carbon number, , it can be seen that the viscosity of the bonding material increases. Therefore, it is preferable to make the carbon number of the organic compound which coat|covers 3rd silver particle (large particle) more than carbon number of the organic compound which coat|covers 2nd silver particle (heavy particle) (lengthens the main chain in a molecule|numerator of an organic compound) .

Claims (19)

A bonding material comprising silver particles, a silver paste comprising a polar solvent and a dispersant, wherein the silver particles include first silver particles having an average primary particle diameter of 1 to 40 nm coated with an organic compound having 8 or less carbon atoms, and 8 carbon atoms Second silver particles having an average primary particle diameter of 41 to 110 nm coated with the following organic compound, and third silver particles having an average primary particle diameter of 120 nm to 10 μm, in 100% by mass of the silver particles in total In contrast, the first silver particles are contained in a proportion of 1.4 to 49 mass %, the second silver particles 36 mass % or less, and the third silver particles 50 to 95 mass %, and the first silver particles with respect to the mass of the second silver particles. The mass ratio of the particles is 14/36 or more, and the average primary particle diameter of the silver particles is an image obtained by observing silver fine particles with a transmission electron microscope (TEM) or metal particles with a scanning electron microscope (SEM) at a predetermined magnification. It is calculated from the primary particle diameter (diameter of a circle corresponding to a circle with the same area) of 100 or more arbitrary silver particles of (SEM image or TEM image), The bonding material characterized by the above-mentioned. The method according to claim 1, wherein the third silver particles are coated with an organic compound having 9 or more carbon atoms, and the ratio of the mass of the first silver particles to 100% by mass of the total of the silver particles is 1.4 to 25% by mass. which is a bonding material. The bonding material according to claim 1, wherein the organic compound having 8 or less carbon atoms is a saturated fatty acid or an unsaturated fatty acid having 1 to 6 carbon atoms. The bonding material according to claim 1, wherein the organic compound having 8 or less carbon atoms is hexanoic acid or sorbic acid. According to claim 1, 2 to 40 mass % of the first silver particles with respect to a total of 100 mass % of the silver particles, and a ratio of the mass of the second silver particles is 2 to 17 mass %, binder. The method according to claim 1, wherein the polar solvent is at least one or more of 1-decanol, 1-dodecanol, 2-ethyl 1,3-hexanediol and 2-methyl-butane-1,3,4-triol. Characterized by the bonding material. The bonding material according to claim 1, wherein the dispersant is at least one or more of a carboxylic acid-based dispersant and a phosphoric acid ester-based dispersant. The bonding material according to claim 1, wherein the total content of the silver particles in the bonding material is 87 to 97 mass%. A bonding method characterized in that the bonding material according to claim 1 is interposed between the objects to be joined and heated to sinter the silver in the bonding material to form a silver bonding layer, and the to-be-joined objects are joined to each other by the silver bonding layer. A method for producing a bonding material comprising silver particles, a silver paste comprising a polar solvent and a dispersing agent, the method comprising: first silver particles having an average primary particle diameter of 1 to 40 nm coated with an organic compound having 8 or less carbon atoms; and 8 or less carbon atoms; silver particles comprising second silver particles having an average primary particle diameter of 41 to 110 nm and third silver particles having an average primary particle diameter of 120 nm to 10 μm coated with an organic compound of With respect to a total of 100 mass %, 1.4-49 mass % of 1st silver particle, 36 mass % or less of 2nd silver particle, and 50-95 mass % of 3rd silver particle, In the mass of 2nd silver particle The ratio of the mass of the first silver particles to the silver particles is 14/36 or more, the silver particles, the polar solvent, and the dispersing agent are kneaded, and the average primary particle diameter of the silver particles is determined using a transmission electron microscope (TEM) or a metal Primary particle diameter (diameter of a circle corresponding to a circle having the same area) of 100 or more arbitrary silver particles of an image (SEM image or TEM image) in which the particles were observed with a scanning electron microscope (SEM) at a predetermined magnification A method for manufacturing a bonding material, characterized in that calculated from 11. The method according to claim 10, wherein the third silver particles are coated with an organic compound having 9 or more carbon atoms, and the ratio of the mass of the first silver particles to 100% by mass of the total of the silver particles is 1.4 to 25% by mass. A method for manufacturing a bonding material. 11. The method according to claim 10, wherein the amount of the first silver particles is 2 to 40% by mass, and the ratio of the mass of the second silver particles to 100% by mass of the total of the silver particles is 2 to 17% by mass. , a method of manufacturing a bonding material. delete delete delete delete delete delete delete

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