Alloy, particles, alloy tape, preform, sintered body, bonded body, electronic device, and method for producing sintered body

Abstract

Provided is an alloy with which it is possible to easily form a sintered body having excellent bonding reliability. This alloy contains a phase in which a metal element (Y) is solid-dissolved in a metal element (X), and the metal element (X) is precipitated on the surface by heat treatment in a gas-phase, liquid-phase or solid-phase atmosphere in which a compound is to be formed with the metal element (Y). Furthermore, the metal element (X) is preferably precipitated on the surface by heat treatment in an oxygen atmosphere, the metal element (X) is preferably Ag and / or Cu, the metal element (X) preferably contains Ag, and the metal element (Y) preferably contains Si and / or Ge.

Description

Technical Field

[0001] This invention relates to alloys, particles, alloy strips, preforms, sintered bodies, joints, electronic devices, and methods for manufacturing sintered bodies. Furthermore, this application claims priority to Japanese Patent Application No. 2023-146497, filed on September 8, 2023, the contents of which are incorporated herein by reference. Background Technology

[0002] Semiconductors used in power devices require high efficiency, low loss, and high-frequency switching, leading to the expanding use of wide-bandgap semiconductors such as SiC and GaN. For these semiconductors, operating temperatures sometimes exceed 200°C, and the bonding materials used for bonding need to maintain high bonding reliability even when operating in the high-temperature range of the semiconductor and under harsh temperature cycling conditions.

[0003] In recent years, the use of silver (Ag) paste, which has high electrical and thermal conductivity, a high melting point, and stability, has attracted attention. However, due to the high melting point of Ag, the substrate can suffer thermal damage when bulk bonding is desired. Therefore, low-temperature sintering technology using nanoparticles has been adopted to reduce the bonding temperature.

[0004] Materials that exhibit high bonding reliability even when operating in such high-temperature ranges and harsh temperature cycling environments include, for example, metal sintered joints as described in Patent Document 1.

[0005] Existing technical documents

[0006] Patent documents

[0007] Patent Document 1: International Publication No. 2018 / 037992 Summary of the Invention

[0008] The problem the invention aims to solve

[0009] However, regarding the sintered metal joint of Patent Document 1, there is a limitation that sintering is required under specific pressure and heating conditions in order to achieve high joint reliability, and there is room for improvement in the joint reliability of the resulting sintered body.

[0010] Furthermore, for typical metal nanoparticles, reducing the particle size lowers the sintering temperature, but this also increases porosity, making them prone to cracking due to repeated heating. Therefore, to ensure sufficient bonding reliability after bonding, it is necessary to carefully define the composition and detailed heat treatment conditions of the sintered metal bond.

[0011] The present invention aims to solve the above-mentioned problems and provide an alloy that can easily form sintered bodies with excellent bonding reliability.

[0012] Problem Solving Methods

[0013] In order to solve the above problems, the inventors conducted in-depth research and found that if the alloy contains a phase formed by the solid solution of metal element Y in metal element X, and the metal element X is precipitated to the surface through a specific treatment, a sintered body with excellent bonding reliability can be easily formed.

[0014] That is, the present invention provides an alloy comprising a phase formed by the solid dissolution of a metallic element Y in a metallic element X, wherein the metallic element X is precipitated on the surface by heat treatment in a gaseous, liquid or solid atmosphere in which a compound is to be formed with the metallic element Y.

[0015] The aforementioned alloy is formed by heat treatment in a gaseous, liquid, or solid atmosphere in which the metal element Y is to form a compound, and the metal element X is precipitated on the alloy surface. The precipitated metal element X can bond strongly to the nearby alloy, thereby enabling excellent bonding reliability.

[0016] The alloy is preferably subjected to heat treatment in an oxygen atmosphere to oxidize the metal element Y and precipitate the metal element X on the alloy surface.

[0017] In the above alloy, the preferred metallic element X is Ag and / or Cu. With the above configuration, it is easy to operate at high temperatures.

[0018] In the above alloy, it is preferable that the metal element X is Ag and the metal element Y is Si and / or Ge. With this configuration, the metal element X and the metal element Y are less likely to form compounds, and the alloy readily contains a phase that has undergone solid solution.

[0019] In the above alloy, it is preferable that the metal element X is Cu, the metal element Y is W, and / or Cr. With this configuration, the metal element X and the metal element Y are less likely to form compounds, and the alloy readily contains a phase that has undergone solid solution.

[0020] The alloy preferably contains metal element Y as a supersaturated solid solution of metal element X. With this configuration, metal element X can be easily precipitated on the alloy surface during heat treatment.

[0021] In the above alloy, the molar ratio of metal element X to metal element Y [metal element X / metal element Y] is preferably 95 / 5 to 10 / 90. With the above configuration, it readily includes a phase formed by the solid solution of metal element Y in metal element X.

[0022] In addition, the present invention provides particles comprising the above-described alloy.

[0023] The average particle size of the silver particles is preferably 0.1~100μm.

[0024] In addition, the present invention provides an alloy strip comprising the above-mentioned alloy.

[0025] In addition, the present invention provides a paste comprising the above-mentioned particles, organic matter, and Ag powder and / or Cu powder.

[0026] In addition, the present invention provides a preform comprising the above-described alloy.

[0027] The aforementioned preforms are preferably in sheet or spherical form.

[0028] In addition, the present invention provides a sintered body of the above alloy.

[0029] In addition, the present invention provides a joint comprising the above-described sintered body.

[0030] In addition, the present invention provides a substrate comprising the above-described bonding body.

[0031] In addition, the present invention provides an electronic device comprising the above-described junction.

[0032] In addition, the present invention provides a method for manufacturing a sintered body, the method comprising a step of heat treatment in a gaseous, liquid or solid atmosphere in which a compound is to be formed with the aforementioned metal element Y.

[0033] In addition, the present invention provides a method for manufacturing a sintered body, the method comprising a step of heat-treating an alloy in an oxygen atmosphere.

[0034] In the above-mentioned method for manufacturing sintered bodies, the oxygen concentration during heat treatment is preferably 0.01 to 30%.

[0035] The effects of the invention

[0036] The alloys according to the present invention can easily provide sintered bodies with excellent bonding reliability. Therefore, electronic devices using the alloys of the present invention exhibit excellent bonding reliability. Attached Figure Description

[0037] Figure 1 This is a SEM image of the sintered body of the present invention.

[0038] Figure 2 This is a cross-sectional view illustrating one embodiment of the electronic device of the present invention.

[0039] Symbol Explanation

[0040] 1. Electronic devices

[0041] 10 substrate

[0042] 20. Conjugate

[0043] 30. The object to be joined Detailed Implementation

[0044] [alloy]

[0045] An alloy comprising an embodiment of the present invention comprises a phase formed by the solid solution of metallic element Y in metallic element X, wherein metallic element X is precipitated on the surface by heat treatment in a gaseous, liquid, or solid atmosphere in which a compound is to be formed with metallic element Y. The alloy is formed by heat treatment in a gaseous, liquid, or solid atmosphere in which a compound is to be formed with metallic element Y, thereby causing metallic element Y in the solid solution phase to form a compound and metallic element X to precipitate on the alloy surface. The precipitated metallic element X can strongly bond with nearby alloys or bonding materials, thereby achieving excellent bonding reliability. Furthermore, since metallic element X precipitates and bonds, bonding can be easily achieved without specific pressure conditions. Only one of metallic element X and metallic element Y may be used in the alloy, or two or more may be used in combination.

[0046] As an element contained in the gaseous, liquid, or solid phase of the compound to be formed with the aforementioned metallic element Y, it is preferable to include, for example, oxygen and sulfur, including sulfur dioxide and hydrogen sulfide. That is, the aforementioned alloy is preferably an alloy in which the aforementioned metallic element Y is oxidized by heat treatment in an oxygen atmosphere, and the aforementioned metallic element X is precipitated on the alloy surface.

[0047] The alloy preferably has a eutectic structure of the aforementioned metal element X and the aforementioned metal element Y. Because the alloy has a eutectic structure, it is easy to include a phase in which the aforementioned metal element X is dissolved in metal element Y.

[0048] Furthermore, in the aforementioned alloy, it is preferable that the phase in which the solid solution has occurred exists on the alloy surface. Specifically, the proportion of the phase in which the solid solution has occurred in the entire alloy surface (100%) is preferably 10% or more, more preferably 15% or more, and even more preferably 20% or more. By ensuring that the proportion of the phase in which the solid solution has occurred on the alloy surface is 10% or more, the metallic element X can be sufficiently precipitated on the surface during sintering.

[0049] Furthermore, the proportion of the phase that has undergone solid solution in 100% of the total amount of the alloy is preferably 3% by mass or more, more preferably 5% by mass or more, and even more preferably 10% by mass or more. By ensuring that the proportion of the phase that has undergone solid solution is 3% by mass or more, the metallic element X can be sufficiently precipitated on the surface during sintering.

[0050] It should be noted that, in this invention, metalloids are also treated as metallic elements. Examples of such metalloids include Si and Ge.

[0051] As the aforementioned metallic element X, it is preferable to include Ag and / or Cu. Since Ag and Cu have high melting points, using them as metallic element X can increase the melting point of the alloy, making it easier to work at high temperatures.

[0052] Examples of the aforementioned metallic element Y include Si, Ge, W, and Cr. Particularly when the aforementioned metallic element X contains Ag, the aforementioned metallic element Y preferably contains Si and / or Ge. When the aforementioned metallic element Y contains Cu, the aforementioned metallic element Y preferably contains W and / or Cr. With the above configuration, the aforementioned metallic element X and the aforementioned metallic element Y are less likely to form compounds, and more likely to form a phase in which solid solution has occurred.

[0053] Furthermore, the aforementioned alloy preferably contains the aforementioned metallic element Y as a supersaturated solid solution of metallic element X. With the above-described configuration, metallic element X can be easily precipitated on the alloy surface during heat treatment in an oxygen atmosphere. It should be noted that, in this invention, the supersaturated solid solution can be prepared by rapidly cooling the melt of metallic element X and metallic element Y, thereby causing metallic element Y to be stably dissolved in metallic element X in a larger quantity than usual. In the aforementioned supersaturated solid solution, it is preferable that metallic element Y is dissolved in 0.5 moles or more of 100 moles of metallic element X, more preferably 1 mole or more, and even more preferably 1.5 moles or more.

[0054] The molar ratio of metal element X to metal element Y [metal element X / metal element Y] is preferably 95 / 5 to 10 / 90, more preferably 93 / 7 to 30 / 70, even more preferably 90 / 10 to 50 / 50, and particularly preferably 90 / 10 to 70 / 30. By setting the above molar ratio to 95 / 5 to 10 / 90, it is easy to include a phase formed by metal element Y dissolved in metal element X. In addition, even when the proportion of metal element Y is large, it is easy to include a phase formed by metal element Y dissolved in a portion of metal element X.

[0055] In the aforementioned alloy (100% by mass), the content of the aforementioned metallic element X is preferably 1 to 99% by mass, more preferably 10 to 98% by mass, and even more preferably 50 to 97% by mass. By making the content of metallic element X 1% by mass or more, it is easy to include the phase formed by the solid solution of metallic element Y in metallic element X. In addition, by making it 99% by mass or less, it is easy to achieve reliable bonding.

[0056] In the aforementioned alloy (100% by mass), the content of metallic element Y is preferably 1 to 99% by mass, more preferably 2 to 90% by mass, and even more preferably 3 to 50% by mass. By making the content of metallic element Y 1% by mass or more, bonding reliability can be easily achieved. In addition, by making it 99% by mass or less, a phase formed by metallic element Y dissolved in metallic element X can be easily included.

[0057] Furthermore, in the total amount of the above alloy (100% by mass), the combined content of metal element X and metal element Y is preferably 90% by mass or more, more preferably 95% by mass or more, and even more preferably 100% by mass.

[0058] Furthermore, the alloy described above may contain components other than metallic elements X and Y. From the viewpoint of ensuring reliable connection, it is preferable that it does not contain these other components. Examples of these other components include elements that readily form compounds with metallic elements X or Y, and compounds containing these elements. When the alloy contains these other components, it is preferable that the content is 10% by mass or less, more preferably 5% by mass or less, and even more preferably 1% by mass or less, relative to the total mass percentage of the alloy.

[0059] There are no particular limitations on the manufacturing method of the above alloy, but it is preferable to produce it by quenching the melt of the above-mentioned metal element X and the above-mentioned metal element Y. In addition, examples of quenching methods include water atomization, gas atomization, and single-roller method.

[0060] The forms of the metal elements X and Y to be melted are not particularly limited, but from the viewpoint of ease of melting, powder form is preferred. In particular, from the viewpoint of efficient melting, a eutectic powder of the metal elements X and Y is preferred as the form of the metal elements X and Y.

[0061] [particle]

[0062] As one embodiment of the present invention, particles comprising the above-described alloy can be cited.

[0063] The average particle size (median particle size) of the aforementioned particles is preferably 0.1 to 100 μm, more preferably 0.3 to 50 μm, even more preferably 0.5 to 30 μm, and particularly preferably 1.0 to 10 μm. By making the average particle size 0.1 μm or more, processing becomes easier; by making it 100 μm or less, the surface area of ​​the particles becomes sufficient, facilitating aggregation in a short time. It should be noted that the aforementioned average particle size (median particle size) can be determined by laser diffraction / scattering.

[0064] Furthermore, there are no particular limitations on the shape of the aforementioned particles; for example, they can be spherical, sheet-like (flat), or polyhedral.

[0065] There are no particular limitations on the manufacturing method of the aforementioned particles. For example, they can be prepared by using gas atomization or water atomization to micronize the molten material of heated metal element X and metal element Y.

[0066] [Alloy Strip]

[0067] As one embodiment of the present invention, an alloy strip comprising the above-mentioned alloy can be cited.

[0068] The thickness of the aforementioned alloy strip is preferably 1 μm to 2 mm, more preferably 10 μm to 1 mm, and even more preferably 50 μm to 0.5 mm. A thickness of 1 μm or more facilitates strip formation, while a thickness of 2 mm or less allows for rapid cooling.

[0069] The width of the aforementioned strip is preferably 0.1 to 100 mm, more preferably 0.5 to 50 mm, and even more preferably 1 mm to 10 mm. A width of 0.1 mm or more facilitates strip formation, while a width of 100 mm or less facilitates rapid cooling.

[0070] There are no particular limitations on the manufacturing method of the aforementioned alloy strip. For example, it can be manufactured by rapidly cooling a molten mixture of heated metal element X and metal element Y using a single-roll method.

[0071] Furthermore, as one embodiment of the present invention, a particle-containing composition comprising the aforementioned particles can be provided. The particle-containing composition is not particularly limited and can be produced in various ways. For example, a particle-containing composition called alloy ink can be prepared by dispersing the particles in a suspended state in a suitable organic solvent (dispersion medium). Alternatively, a particle-containing composition called paste can be prepared by dispersing the aforementioned particles in a mixed state in an organic solvent. The particle-containing composition is preferably a paste. It should be noted that only one type of particle may be used in the particle-containing composition, or two or more may be used in combination.

[0072] [paste]

[0073] In addition to the aforementioned particles, the above-mentioned paste also contains organic matter.

[0074] Examples of the aforementioned organic compounds include: reducing organic compounds, basic compounds, coordination organic compounds other than those belonging to the category of basic compounds, resins, organic solvents, etc. Only one of the aforementioned organic compounds may be used, or two or more may be used in combination.

[0075] <Reduced organic compounds>

[0076] Examples of reducing organic compounds include, but are not limited to, substances listed below as organic solvents. Examples include: alcohols (lower alcohols such as ethanol, higher alcohols such as palmitol), aldehydes (formaldehyde, acetaldehyde, cyclic trimers and tetramers of these aldehydes), amino acids, organic acids (carboxylic acids, etc.), and aromatic compounds (polyphenols, phenolic acid compounds, etc.). From the viewpoint of exhibiting acidity, organic acids (carboxylic acids, etc.) and aromatic compounds are preferred; from the viewpoint of being easily handled at room temperature and having low toxicity, carboxylic acids are more preferred. Only one of these compounds may be used, or two or more may be used.

[0077] Examples of the aforementioned carboxylic acids include formic acid, acetic acid, lactic acid, propionic acid, acrylic acid, malic acid, hexanoic acid, succinic acid, octanoic acid, tartaric acid, and oxalic acid. Among these, formic acid and oxalic acid are preferred from the viewpoint of easily obtaining sintered bodies with excellent reducing properties and excellent electrical conductivity.

[0078] From the viewpoint of excellent reducing properties and superior void suppression, the aforementioned reducing organic compound preferably contains formic acid. Furthermore, from the viewpoint of being able to exert reducing properties over a wide temperature range, the aforementioned reducing organic compound preferably contains, in addition to formic acid, a compound with a boiling point higher than formic acid (especially a compound with a boiling point higher than that of a coordination organic compound).

[0079] When formic acid is included as a reducing organic compound, the content of formic acid relative to the total amount of the reducing organic compound (100% by mass) is preferably 50% by mass or more, more preferably 60% by mass or more, and even more preferably 80% by mass or more. Furthermore, when formic acid is included along with other reducing organic compounds (e.g., compounds with boiling points higher than formic acid), the content of the other reducing organic compounds relative to 1 mole of formic acid is preferably 0.1 moles or less, more preferably 0.05 moles or less.

[0080] Relative to the total amount of the above paste (100% by mass), the content of the above-mentioned reducing organic matter is preferably 5% by mass or less (e.g., 0.1 to 5% by mass), more preferably 0.1 to 4.0% by mass, further preferably 0.2 to 3.7% by mass, and particularly preferably 0.3 to 3.5% by mass.

[0081] <Alkaline compounds>

[0082] As for the aforementioned alkaline compound, there is no particular limitation as long as it can function as a base and achieve the effects of the present invention. Specific examples include nitrogen-containing compounds such as ammonia, amine compounds, phosphine, and phosphorus-containing compounds such as phosphate esters. From the viewpoint of easily obtaining a sintered body with excellent electrical conductivity, nitrogen-containing compounds represented by the following formula (1) are preferred.

[0083] [Chemical Formula 1]

[0084]

[0085] In equation (1), R a ~R c "Same or different" refers to a hydrogen atom or a hydrocarbon group that may have substituents. "Same or different" also refers to a substituent selected from at least one group chosen from amino, N-substituted amino, N,N-substituted amino, imino, N-substituted imino, and hydroxyl. Wherein, R... a ~R c They are not both hydrogen atoms. The double lines containing dashed lines indicate either a single or double bond; in the case of a double bond, R is absent. c R a ~R c Any two atoms in the atom can also bond together with each other and form a ring with the adjacent nitrogen atom.

[0086] As R a ~R c The hydrocarbon group can be an aliphatic hydrocarbon group, an alicyclic hydrocarbon group, or an aromatic hydrocarbon group, among which aliphatic hydrocarbon groups and alicyclic hydrocarbon groups are preferred, and aliphatic hydrocarbon groups are more preferred.

[0087] Examples of aliphatic hydrocarbon groups include straight-chain or branched alkyl groups, straight-chain or branched alkenyl groups, straight-chain or branched alkynyl groups, and straight-chain or branched alkyl groups, with straight-chain or branched alkyl groups being preferred.

[0088] The linear or branched alkyl group is preferably a linear alkyl group with 1 to 20 carbon atoms, more preferably a linear alkyl group with 1 to 15 carbon atoms, or preferably a branched alkyl group with 3 to 12 carbon atoms, more preferably a linear alkyl group with 3 to 8 carbon atoms, and even more preferably a branched alkyl group with 3 to 6 carbon atoms. Examples include: methyl, ethyl, propyl, butyl, pentyl, hexyl, decyl, dodecyl, tetradecyl, octadecyl, isopropyl, isobutyl, sec-butyl, tert-butyl, 2-ethylhexyl, etc.

[0089] The linear or branched alkenyl group is preferably a linear alkenyl group with 2 to 12 carbon atoms, more preferably 2 to 8 carbon atoms, and even more preferably 2 to 4 carbon atoms. Alternatively, it is preferably a branched alkenyl group with 3 to 12 carbon atoms, more preferably 3 to 8 carbon atoms, and even more preferably 3 to 6 carbon atoms. Examples include: vinyl, 1-propenyl, 2-propenyl, 1-butenyl, 2-butenyl, 3-butenyl, 1-pentenyl, 2-pentenyl, 3-pentenyl, 4-pentenyl, 1-hexenyl, 3-hexenyl, 5-hexenyl, 1-heptenyl, 1-octenyl, 1-nonenyl, 1-decenyl, isopropenyl, 2-methyl-1-propenyl, methallyl, 3-methyl-2-butenyl, 4-methyl-3-pentenyl, etc.

[0090] The linear or branched alkynyl group is preferably a linear alkynyl group with 2 to 12 carbon atoms, more preferably 2 to 8 carbon atoms, and even more preferably 2 to 4 carbon atoms. Alternatively, it is preferably a branched alkynyl group with 3 to 12 carbon atoms, more preferably 3 to 8 carbon atoms, and even more preferably 3 to 6 carbon atoms. Examples include: ethynyl, 1-propynyl, 2-propynyl, 1-butynyl, 2-butynyl, 3-butynyl, 1-pentynyl, 2-pentynyl, 3-pentynyl, 4-pentynyl, 1-hexynyl, 2-hexynyl, 3-hexynyl, 4-hexynyl, 5-hexynyl, 1-hepynyl, 1-octyynyl, 1-nonynyl, 1-decynyl, trimethylsilylethynyl, triethylsilylethynyl, etc.

[0091] The linear or branched alkane chain is preferably a linear alkane chain with 1 to 12 carbon atoms, more preferably 1 to 8 carbon atoms, and even more preferably 2 to 4 carbon atoms. Alternatively, it is preferably a branched alkane chain with 3 to 12 carbon atoms, more preferably 3 to 8 carbon atoms, and even more preferably 3 to 6 carbon atoms. Examples include: methyl alkane, propylene alkane, isopropylene alkane, butyl alkane, isobutyl alkane, sec-butyl alkane, pentyl alkane, isopentyl alkane, octyl alkane, isooctyl alkane, etc.

[0092] Examples of alicyclic hydrocarbon groups include cycloalkyl and cycloalkenyl groups.

[0093] The cycloalkyl group is preferably a cycloalkyl group with 3 to 12 carbon atoms, more preferably a cycloalkyl group with 4 to 10 carbon atoms, and even more preferably a cycloalkyl group with 5 to 8 carbon atoms. Examples include cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, cyclononyl, cyclodecyl, etc.

[0094] The cycloalkenyl group is preferably a cycloalkenyl group with 3 to 12 carbon atoms, more preferably a cycloalkenyl group with 4 to 10 carbon atoms, and even more preferably a cycloalkenyl group with 5 to 8 carbon atoms, for example: cyclopentenyl, cyclohexenyl, etc.

[0095] As an aromatic hydrocarbon group, it is preferably an aryl group with 6 to 18 carbon atoms, more preferably with 6 to 14 carbon atoms, and even more preferably with 6 to 10 carbon atoms, such as phenyl, naphthyl, etc.

[0096] In equation (1), the double lines containing dashed lines represent single or double bonds. When the double lines containing dashed lines represent double bonds, R does not exist. c R in equation (1) a and R b The bonded nitrogen atom represents an imino or an N-substituted imino.

[0097] R a ~R c The total number of amino groups, N-substituted amino groups, and N,N-substituted amino groups that may be present is preferably 0 to 6, more preferably 1 to 4, and even more preferably 1 to 2.

[0098] R a ~R c The total number of imino groups and N-substituted imino groups that may be present is preferably 0 to 4, more preferably 1 to 3, and even more preferably 1 to 2.

[0099] R a ~R c The total number of hydroxyl groups that may be present is preferably 0 to 6, more preferably 1 to 4, and even more preferably 1 to 2.

[0100] The substituents of the above-mentioned N-substituted amino, N,N-substituted amino, and N-substituted imino groups are the same as those of the above-mentioned R. a ~R c The hydrocarbon groups involved are the same.

[0101] R a ~R c Any two atoms in the ring can bond to each other and form a ring together with the adjacent nitrogen atom. Examples of the rings that can be formed include: pyrrolidine ring, pyrrololine ring, piperidine ring, pyrrole ring, imidazoline ring, imidazoline ring, piperazine ring, imidazoline ring, pyridine ring, diazine ring, triazine ring, etc.

[0102] R a ~R cThe hydrocarbon group involved can have substituents other than amino, N-substituted amino, N,N-substituted amino, imino, N-substituted imino, or hydroxyl. Examples of such substituents include: halogen atoms (fluorine, chlorine, bromine, iodine), oxo groups, substituted oxygen groups (alkoxy groups with 1 to 4 carbon atoms, aryl groups with 6 to 10 carbon atoms, aryloxy groups with 6 to 10 carbon atoms, arylalkoxy groups with 7 to 16 carbon atoms, acyloxy groups with 1 to 4 carbon atoms, etc.), carboxyl groups, substituted oxygen carbonyl groups (alkoxy carbonyl groups with 1 to 4 carbon atoms, aryloxy carbonyl groups with 6 to 10 carbon atoms, arylalkoxy carbonyl groups with 7 to 16 carbon atoms, etc.), cyano, nitro, sulfono, mercapto, heterocyclic groups, etc.

[0103] As a specific example of a basic compound represented by formula (1), one could cite, for example, R in formula (1). a ~R c At least one of them is a linear or branched alkylamine; R in formula (1) a R b Independently composed of hydrogen atoms or straight-chain or branched alkyl groups, R c It is a monoalkyl alcohol amine with a straight-chain or branched alkyl group having one hydroxyl group; R in formula (1) a It is a hydrogen atom or a straight-chain or branched alkyl group, R b and R c Dialkylamines that are the same or different from linear or branched alkyl groups having a hydroxyl group; R in formula (1) a ~R c The same or different are trialkylolamines with a straight-chain or branched alkyl group having a hydroxyl group; R in formula (1) a R b The same or different are hydrogen atoms, straight-chain or branched alkyl groups, R c It is an aminoalkane diol with two hydroxyl groups, either linear or branched alkyl groups; R in formula (1) a ~R c It is a diamine having a total of 1 amino group; R in formula (1) a ~R c It is a triamine having a total of 2 amino groups; R in formula (1) a ~R c It is a diaminoalkanol having a total of 1 amino group and a total of 1 hydroxyl group; R in formula (1) a ~R c An imidazole compound containing a total of 1 imino group and forming a ring by containing the nitrogen atom of the imino group; R in formula (1) a R bNitrogen-containing aromatic compounds (pyridine compounds, diazine compounds, triazine compounds, etc.) whose bonded nitrogen atom is an imino group and which contains the imino group to form a ring.

[0104] Examples of the aforementioned alkylamines include: methylamine, ethylamine, propylamine, butylamine, pentanamine, dimethylamine, diethylamine, dipropylamine, dibutylamine, dipentanamine, piperidine, trimethylamine, triethylamine, dimethyldecylamine, dimethyldodecylamine, 4-dimethylaminopyridine, 2-aminopyrazine, 2-aminopyrimidine, 3-aminopyridazine, 2-aminotriazine, diazabicyclononene, diazabicycloundecene, etc.

[0105] Examples of the aforementioned monoalkanolamines include: 2-aminoethanol, 3-aminopropanol, 1-amino-2-propanol, 1-amino-2-methyl-2-propanol, 2-amino-2-methyl-1-propanol, 4-amino-1-butanol, 6-amino-1-hexanol, 10-amino-1-decanol, 12-amino-1-dodecanol, N-methyl-2-aminoethanol, N-ethyl-2-aminoethanol, N-propyl-2-aminoethanol, 2-dimethylaminoethanol, 6-diethylaminohexanol, 1-(2-hydroxyethyl)pyrrolidine, 2-(hydroxymethyl)pyrrolidine, 2-(2-hydroxyethyl)-1-methylpyrrolidine, 1-piperidineethanol, 1-ethanol-4-propanolpiperidine, etc.

[0106] Examples of the aforementioned dialkyl alcoholamines include: diethanolamine, di-n-propanolamine, diisopropanolamine, di-n-butanolamine, diisobutanolamine, N-methyldiethanolamine, etc.

[0107] Examples of the aforementioned trialkylolamines include triethanolamine, tri-n-propanolamine, triisopropanolamine, tri-n-butanolamine, and triisobutanolamine.

[0108] Examples of the aforementioned aminoalkane diols include: 1-amino-2,3-propanediol, 4-amino-1,2-butanediol, 4-amino-1,3-butanediol, 2-amino-1,3-propanediol, 2-amino-2-methyl-1,3-propanediol, 1-methylamino-2,3-propanediol, 1-ethylamino-2,3-propanediol, 1-propylamino-2,3-propanediol, 1-butylamino-2,3-propanediol, 3-dimethylamino-1,2-propanediol, and 2-diethylamino-1,3-propanediol.

[0109] Examples of the aforementioned diamines include: 1,3-propanediamine, 2,2-dimethyl-1,3-propanediamine, 1,4-butanediamine, 1,5-pentanediamine, 1,6-hexanediamine, 1,7-heptanediamine, 1,8-octanediamine, 1,5-diamino-2-methylpentane, N,N'-dimethylethylenediamine, N,N'-diethylethylenediamine, N,N'-dimethyl-1,3-propanediamine, N,N'-diethyl-1,3-propanediamine, N,N'-dimethyl-1,4-butanediamine, N,N'-diethyl-1 4-Butanediamine, N,N'-dimethyl-1,6-hexanediamine, N,N-dimethylethylenediamine, N,N-diethylethylenediamine, N,N-dimethyl-1,3-propanediamine, N,N-diethyl-1,3-propanediamine, N,N-dimethyl-1,4-butanediamine, N,N-diethyl-1,4-butanediamine, N,N-dimethyl-1,6-hexanediamine, 1,2-cyclohexanediamine, 1,4-cyclohexanediamine, piperazine, N-methylpiperazine, N-ethylpiperazine, N,N'-dimethylpiperazine, homopiperazine, etc.

[0110] Examples of the aforementioned triamines include: diethylenetriamine, N,N,N',N”,N”-pentamethyldiethylenetriamine, N,N,N',N”,N”-penta(2-hydroxypropyl)diethylenetriamine, 3,3'-diaminodipropylamine, N-(3-aminopropyl)-N-methyl-1,3-propanediamine, N'-[3-(dimethylamino)propyl]-N,N-dimethyl-1,3-propanediamine, 2,6,10-trimethyl-2,6,10-triazaundecane, N-(2-aminoethyl)piperazine, 1,4,7-triazacyclononane, N,N,N',N”,N”-penta(2-hydroxypropyl)diethylenetriamine, 1-(2-aminoethyl)-4-methylpiperazine, 1-(2-dimethylaminoethyl)-4-methylpiperazine, etc.

[0111] Examples of the aforementioned diaminoalkanols include: 1,3-diaminopropane-2-ol, 2-(2-aminoethylamino)ethanol, 2-(2-aminopropylamino)ethanol, 2-(2-aminoethylmethylamino)ethanol, 1-(2-hydroxyethyl)piperazine, 4-methylpiperazine-1-ethanol, 1,4-bis(2-hydroxyethyl)piperazine, etc.

[0112] Examples of the aforementioned imidazole compounds include: imidazole, 2-methylimidazolium, 2-propylimidazolium, N-methylimidazolium, N-propylimidazolium, N-butylimidazolium, 1-(2-hydroxyethyl)imidazolium, 2-ethyl-4-methylimidazolium, 1,2-dimethylimidazolium, 1-benzyl-2-methylimidazolium, 1-cyanoethyl-2-methylimidazolium, 1-cyanoethyl-2-ethyl-4-methylimidazolium, 2-phenyl-4,5-dihydroxymethylimidazolium, 1-acetylimidazolium, 2-hydroxybenzimidazole, etc.

[0113] Examples of nitrogen-containing aromatic compounds mentioned above include: pyridine, α-methylpyridine, β-methylpyridine, γ-methylpyridine, 2,6-dimethylpyridine, 2,3-dimethylpyridine, pyrazine, 2-hydroxypyrazine, pyrimidine, 2-hydroxypyrimidine, 4-hydroxypyrimidine, pyridazine, 3-hydroxypyridazine, 4-hydroxypyridazine, triazine, 2-hydroxytriazine, etc.

[0114] From the viewpoint that metal ions formed by the dissolution of metal oxides on the surface of metal particles can be easily stabilized through chelation coordination, the basic compound contained in the above-mentioned paste is preferably a basic compound with chelation coordination properties having an ethylenediamine structure or an ethanolamine structure in its molecular structure. The amino group in the above structure can be any one of primary amino, secondary amino, or tertiary amino groups, and from the viewpoint of suppressing side reactions between the basic compound and reducing organic matter, a tertiary amino group is preferred.

[0115] The aforementioned basic compound preferably contains, in addition to the basic compound with the aforementioned chelating coordination properties, an alkylamine having at least one straight-chain alkyl group having 1 to 20 carbon atoms (preferably 1 to 15 carbon atoms).

[0116] In the above-mentioned paste, the molar ratio (basic group / acidic group) of the basic group of the basic compound to the acidic group of the reducing organic compound is 0.4 or more, preferably 0.5 or more, more preferably 0.6 or more, further preferably 1.0 or more, and particularly preferably 1.6 or more. When the above molar ratio is less than 0.4, sometimes the reaction between the reducing organic compound and the metal based on the acidic group occurs, and the metal paste becomes a solid in a coagulated state and cannot maintain the paste state. The above molar ratio is preferably 2.0 or less, more preferably 1.8 or less, and further preferably 1.7 or less. When the above molar ratio is 2.0 or less, the surface of the metal particles is easily reduced, and the conductivity of the sintered body is excellent. It should be noted that the number of moles of acidic groups contained in the reducing organic compound refers to the value obtained by multiplying the number of moles of the reducing organic compound by the number of acidic groups contained in the reducing organic compound, and the number of moles of basic groups contained in the basic compound refers to the value obtained by multiplying the number of moles of the basic compound by the number of basic groups contained in the basic compound.

[0117] Relative to the total amount (100% by mass) of the above paste, the content of the above alkaline compound in the above paste is preferably 0.1 to 10% by mass, more preferably 0.3 to 9% by mass, and even more preferably 0.5 to 8% by mass.

[0118] <Coordination Organic Compounds>

[0119] The aforementioned coordination organic compound is a compound located on the metal surface of the aforementioned metal particles, and is other than compounds belonging to the aforementioned basic compounds. Preferably, the aforementioned coordination organic compound has a boiling point higher than at least one of the aforementioned reducing organic compounds. In this case, the aforementioned coordination organic compound is more likely to remain during calcination than the aforementioned reducing organic compounds, and it easily inhibits the contact between the aforementioned reducing organic compounds and the active metal surface; therefore, the decomposition of the aforementioned reducing organic compounds is suppressed.

[0120] Examples of such coordinating organic compounds include at least one compound selected from compounds having a carboxyl group, compounds having a ketone group (e.g., diketones such as acetylacetone, β-keto esters), compounds having a hydroxyl group, compounds having a sulfonyl group, and compounds having a thiol group. From the viewpoint of easily causing the molten metal oxide to precipitate as small-diameter metal particles, compounds having a carboxyl group are preferred.

[0121] The compounds containing carboxyl groups are preferably monocarboxylic or dicarboxylic acids, and from the viewpoint that it is easier to sinter the metal particle aggregates in subsequent processes, monocarboxylic acids are more preferred.

[0122] The aforementioned carboxylic acids can be those identical to those described for the reducing organic compounds. Furthermore, from the viewpoint of being readily available and having low toxicity and odor, they can be carboxylic acids with 2 to 15 carbon atoms (preferably 5 to 12, more preferably 8 to 10). Specific examples include: acetic acid (boiling point 118°C), lactic acid (boiling point 122°C), propionic acid (boiling point 141°C), acrylic acid (boiling point 141°C), malic acid (boiling point 167°C), valeric acid (boiling point 186°C), hexanoic acid (boiling point 205°C), heptanoic acid (boiling point 223°C), 2-ethylhexanoic acid (boiling point 228°C), succinic acid (boiling point 235°C), octanoic acid (boiling point 237°C), nonanoic acid (boiling point 254°C), decanoic acid (boiling point 269°C), dodecanoic acid (boiling point 299°C), tartaric acid (boiling point 275°C), and oxalic acid (boiling point 365°C). Since carboxylic acids function as both reducing and coordinating organic compounds, when using a carboxylic acid as a coordinating organic compound, it is sufficient to combine it with other carboxylic acids having higher boiling points than the one with the lowest boiling point. In this case, the carboxylic acid with the relatively higher boiling point primarily functions as a protecting agent, while the carboxylic acid with the relatively lower boiling point primarily functions as a reducing agent.

[0123] From the viewpoint that it is less volatile than formic acid (boiling point 101°C), the above-mentioned carboxylic acid preferably has a boiling point of more than 110°C under normal pressure, more preferably more than 150°C, and even more preferably more than 200°C.

[0124] In the above paste, the ratio of the molar number of coordinating functional groups in the above-mentioned coordinating organic compound to the molar number of acidic groups in the above-mentioned reducing organic compound (coordinating functional group / acidic group) is preferably 0.05 to 1.20, more preferably 0.40 to 1.10, and even more preferably 0.50 to 0.70. When the above molar ratio is 0.05 or higher, it is easy to obtain the precipitation of small-diameter metal particles, and when the above molar ratio is 1.20 or lower, the coordinating organic compound is less likely to remain during firing.

[0125] The molar ratio (coordinating functional group / basic compound) of the aforementioned coordination organic compound in the paste to the basic group of the aforementioned basic compound is preferably 0.10 to 1.00, more preferably 0.15 to 0.75, and even more preferably 0.20 to 0.60. When the above molar ratio is 0.10 or higher, it is easy to obtain the precipitation of small-diameter metal particles; when the above molar ratio is 1.00 or lower, the coordination organic compound is less likely to remain during firing.

[0126] Relative to the total amount (100% by mass) of the above paste, the content of the above-mentioned coordinating organic compound in the above paste is preferably 0.1 to 10% by mass, more preferably 0.2 to 9% by mass, and even more preferably 0.3 to 8% by mass.

[0127] <Resin>

[0128] Examples of the aforementioned resins include: thermoplastic resins (polyester resins, polyamide resins, polyurethane resins, polyimide resins, polyolefin resins, (meth)acrylic resins, styrene resins, halogenated vinyl resins, polyvinyl acetal resins, cellulose resins (ethyl cellulose resins, alkyl cellulose resins, etc.), thermoplastic silicone resins, etc.) and thermosetting resins (epoxy resins, unsaturated polyester resins, diallyl phthalate resins, silicone resins, etc.). From the viewpoint of mitigating internal stress during heating, thermoplastic resins are preferred, while from the viewpoint of the adhesion and strength of the metal particle aggregates to the substrate, (meth)acrylic resins and polyvinyl acetal resins are preferred.

[0129] Examples of polyvinyl acetal resins mentioned above include polyvinyl butyral.

[0130] Relative to the total amount (100% by mass) of the above paste, the content of the above resin in the above paste is preferably 1.0% by mass or less, more preferably 0.05 to 1.0% by mass, and even more preferably 0.1 to 0.9% by mass.

[0131] <Organic solvents>

[0132] To adjust flowability (viscosity) and workability, the paste may also contain an organic solvent. The organic solvent is preferably an organic solvent comprising at least organic solvent (a), organic solvent (b), and organic solvent (c). Organic solvent (a), organic solvent (b), and organic solvent (c) are different compounds and satisfy the following formulas (1) to (6). Only one of organic solvent (a), organic solvent (b), and organic solvent (c) may be used, or two or more may be used.

[0133] 150℃≤Ta≤250℃(1)

[0134] 150℃≤Tb≤250℃(2)

[0135] 250℃≤Tc≤350℃(3)

[0136] δa≥10.0(4)

[0137] δc≤9.0(5)

[0138] δc≤δb≤δa(6)

[0139] In the formula, Ta~Tc represent the boiling points of organic solvents (a)~(c), respectively, and δa~δc represent the Hansen solubility parameters of organic solvents (a)~(c), respectively. It should be noted that in this specification, the Hansen solubility parameter is referred to as the "SP value", and sometimes expressed as "δ".

[0140] It should be noted that the organic solvents (a) to (c) are any solvents that can be uniformly dissolved into a liquid state when mixed in the proportions used in the above-mentioned bonding conductor paste. Each of them can be liquid or solid at room temperature.

[0141] The organic solvent (a) at least satisfies formula (1). That is, the boiling point Ta of the organic solvent (a) satisfies 150℃≤Ta≤250℃, preferably 150℃<Ta<250℃, more preferably 155℃≤Ta≤220℃, and even more preferably 160℃≤Ta≤200℃. By using an organic solvent (a) with a boiling point within the above range, the organic solvent readily volatilizes during sintering, making it easy to form a sintered body.

[0142] The organic solvent (a) at least satisfies formula (4) [δa ≥ 10.0]. The SP value δa of the organic solvent (a) is 10.0 or more, preferably 10.3 or more, and more preferably 10.4 or more, within the range of satisfying formula (6). By making the above-mentioned δa 10.0 or more, the dispersibility of the above-mentioned particles with the Ag and / or Cu powders is excellent, and the separation of metal particles from the organic solvent is less likely to occur. The δa of the organic solvent (a) is, for example, 16.0 or less, and can be 15.0 or less.

[0143] Examples of organic solvents (a) include alcohol solvents, urea solvents, and aprotic polar solvents. Among the aforementioned alcohol solvents, compounds having one or more hydroxyl groups are examples, with tertiary alcohols and ether alcohols being preferred. The aforementioned alcohol solvents may also have two or more hydroxyl groups. Ether alcohols are compounds having both an ether bond and a hydroxyl group, and examples include (poly)alkylene glycol monoalkyl ethers and alkoxy-substituted alcohols.

[0144] Examples of organic solvents (a) include: pinacol (δ 10.7, boiling point 172 °C), tetramethylurea (δ 10.6, boiling point 177 °C), 3-methoxybutanol (δ 10.6, boiling point 161 °C), 1-methylcyclohexanol (δ 10.4, boiling point 155 °C), and methyl carbitol (diethylene glycol monomethyl ether) (δ 10.7, boiling point 193 °C).

[0145] The organic solvent (b) at least satisfies formula (2). That is, the boiling point Tb of the organic solvent (b) satisfies 150℃≤Tb≤250℃, preferably 150℃<Tb<250℃, more preferably 180℃≤Tb≤248℃, and even more preferably 200℃≤Tb≤245℃. By using an organic solvent (b) with a boiling point within the above range, the organic solvent readily volatilizes during sintering, making it easy to form a sintered body. In addition, by using an organic solvent (b) with a boiling point below 250℃, the generation of voids during sintering can be suppressed.

[0146] The organic solvent (b) at least satisfies formula (6). The SP value δb of the organic solvent (b) is preferably 8.0 to 12.0, more preferably 8.5 to 11.0, and even more preferably 9.0 to 10.5 within the range of formula (6). When δb is within the above range, the compatibility of organic solvent (a) and organic solvent (c) is improved, they are not easy to separate, and they tend to have better continuous discharge stability and storage stability.

[0147] Examples of organic solvents (b) include alcohol solvents, ester solvents, ketone solvents, and amine solvents. Among the aforementioned alcohol solvents, solvent compounds having one or more hydroxyl groups are examples, with tertiary alcohols, ether alcohols, and ester alcohols being preferred. Ether alcohols are compounds having both an ether bond and a hydroxyl group, and examples include (poly)alkylene glycol monoalkyl ethers and alkoxy-substituted alcohols. Ester alcohols are compounds having both an ester bond and a hydroxyl group, and examples include (poly)alkylene glycol monoalkyl ether monoesters. Examples of ester solvents include diacetates of (poly)alkylene glycols and other diols. Cyclic ketone solvents are preferred. Alkylamine solvents are preferred.

[0148] As an organic solvent (b), it can be selected based on the premise that it satisfies equation (6) in relation to organic solvents (a) and (c). Specifically, it can be used for example: d-Camphor (δ10.4, boiling point 204℃), 1-Heptanol (δ10.0, boiling point 177℃), butylcarbitol (diethylene glycol monobutyl ether) (δ10.2, boiling point 231℃), ethylcarbitol (diethylene glycol monoethyl ether) (δ10.5, boiling point 196℃), tripropylene glycol monomethyl ether (δ9.4, boiling point 243℃), α-terpineol (δ9.3... The following are listed: dihydroterpineol (δ 9.0, boiling point 210℃), 1,3-butanediol diacetate (δ 9.2, boiling point 232℃), propylene glycol diacetate (δ 9.3, boiling point 190℃), butyl carbitol acetate (δ 9.0, boiling point 247℃), dipropylene glycol butyl ether (δ 9.2, boiling point 230℃), isophorone (δ 9.5, boiling point 213℃), 1-decyl alcohol (δ 9.6, boiling point 230℃), propylene glycol monobutyl ether (δ 9.0, boiling point 170℃), 1-nonanol (δ 9.8, boiling point 214℃), etc.

[0149] The boiling point Tb of the organic solvent (b) is preferably higher than the boiling point Ta of the organic solvent (a), that is, preferably Tb > Ta. The temperature difference between Tb and Ta [Tb-Ta] is preferably 2°C or more, more preferably 5°C or more, and even more preferably 10°C or more. When the above temperature difference is 2°C or more, the generation of voids during sintering can be further suppressed.

[0150] The organic solvent (c) at least satisfies equation (3). That is, the boiling point Tc of the organic solvent (c) satisfies 250℃≤Tc≤350℃, preferably 250℃<Tc<350℃, more preferably 250℃<Tc≤320℃, and even more preferably 250℃<Tc≤300℃. By using an organic solvent (c) with a boiling point within the above range, the rapid volatilization of organic solvent (a) and organic solvent (b) during sintering can be suppressed, thereby suppressing the formation of voids.

[0151] The organic solvent (c) must at least satisfy formula (5) [δc ≤ 9.0]. The SP value δc of the organic solvent (c) is 9.0 or less, preferably 8.7 or less, and more preferably 8.5 or less. By making the above-mentioned δc 9.0 or less, the generation of voids during sintering can be suppressed. The δc of the organic solvent (c) is, for example, 6.0 or more, and can be 7.0 or more.

[0152] Examples of organic solvents (c) include ether solvents, alkane solvents, and ester solvents. Examples of ether solvents include (poly)alkylene glycol dialkyl ethers. Examples of alkane solvents are alkanes with 14 or more carbon atoms (e.g., 14 to 20 carbon atoms). Examples of ester solvents are esters of (poly)alkylene glycol alkyl ethers and fatty acids.

[0153] Examples of organic solvents (c) include: dibutylcarbidol (diethylene glycol dibutyl ether) (δ8.3, boiling point 255℃), tetradecane (δ7.9, boiling point 254℃), hexadecane (δ8.0, boiling point 287℃), etc.

[0154] The boiling point Tc of the organic solvent (c) is preferably higher than the boiling point Tb of the organic solvent (b), that is, preferably Tc > Tb. The temperature difference between Tc and Tb [Tc-Tb] is preferably 2°C or more, more preferably 6°C or more, and even more preferably 10°C or more. When the above temperature difference is 2°C or more, the generation of voids during sintering can be further suppressed.

[0155] The boiling point Tc of the organic solvent (c) is preferably higher than the boiling point Ta of the organic solvent (a), that is, preferably Tc > Ta. The temperature difference between Tc and Ta [Tc-Ta] is preferably 30°C or more, more preferably 50°C or more, and even more preferably 60°C or more. When the above temperature difference is 30°C or more, the generation of voids during sintering can be further suppressed.

[0156] The SP values ​​δa, δb, and δc of organic solvent (a), organic solvent (b), and organic solvent (c) satisfy the relationship described in equation (6) above [δc ≤ δb ≤ δa]. Preferably, δb is higher than δc, i.e., preferably δc < δb. Furthermore, preferably, δa is higher than δb, i.e., preferably δb < δa.

[0157] The difference between δb and δc [δb-δc] is preferably 0.1 or more, more preferably 0.2 or more, and even more preferably 0.5 or more. When the difference is 0.1 or more, the dispersibility of the metal particles is better, and the continuous discharge stability is better. The difference is preferably 2.0 or less, more preferably 1.5 or less, and even more preferably 1.3 or less. When the difference is 2.0 or less, the particles are less likely to separate from the Ag and / or Cu powder and organic solvents, and the continuous discharge stability and storage stability are better.

[0158] The difference between δa and δb [δa-δb] is preferably 0.1 or more, more preferably 0.2 or more, and even more preferably 0.5 or more. When the difference is 0.1 or more, the dispersibility of the metal particles is better, and the continuous discharge stability is better. The difference is preferably 2.5 or less, more preferably 2.0 or less, and even more preferably 1.8 or less. When the difference is 2.5 or less, the metal particles are less likely to separate from the organic solvent, and the continuous discharge stability and storage stability are better.

[0159] Based on equations (4) and (5), the difference between δa and δc [δa-δc] is 1.0 or more, preferably 1.5 or more, and more preferably 2.0 or more. When the difference is 1.0 or more, the generation of voids during sintering can be further suppressed. The difference is preferably 5.0 or less, more preferably 4.0 or less, and even more preferably 3.0 or less. When the difference is 5.0 or less, the particles are less likely to separate from the Ag and / or Cu powder and organic solvent, resulting in better continuous discharge stability and storage stability.

[0160] The ratio of organic solvent (a) to the total amount of organic solvent (a), organic solvent (b), and organic solvent (c) in 100% by mass [organic solvent (a) / {organic solvent (a) + organic solvent (b) + organic solvent (c)}] is preferably 5 to 70% by mass, more preferably 10 to 60% by mass, and even more preferably 15 to 50% by mass. When the above ratio is within the above range, the organic solvent is easily volatilized during sintering, and a sintered body can be easily formed. Moreover, the dispersibility of the above particles with the Ag and / or Cu powders is better.

[0161] The ratio of organic solvent (b) to the total amount of organic solvent (a), organic solvent (b) and organic solvent (c) in a 100% mass percentage [organic solvent (b) / {organic solvent (a) + organic solvent (b) + organic solvent (c)}] is preferably 5 to 70% by mass, more preferably 10 to 60% by mass, and even more preferably 15 to 50% by mass. When the above ratios are within the above ranges, the compatibility of each organic solvent is excellent, and the continuous discharge stability and storage stability are even better.

[0162] The ratio of organic solvent (c) to the total amount of organic solvent (a), organic solvent (b), and organic solvent (c) in 100% by mass [organic solvent (c) / {organic solvent (a) + organic solvent (b) + organic solvent (c)}] is preferably 5 to 70% by mass, more preferably 10 to 60% by mass, and even more preferably 15 to 50% by mass. When the above ratio is within the above range, the generation of voids during sintering can be further suppressed.

[0163] The content of organic solvent (c) is preferably 20 to 400 parts by mass, more preferably 30 to 300 parts by mass, and even more preferably 50 to 200 parts by mass, relative to 100 parts by mass of organic solvent (a). When the content is within the above range, the balance between the amount of organic solvent (a) and organic solvent (c) is good, the void suppression during sintering and the dispersibility of the above particles with the Ag and / or Cu powders are better.

[0164] Relative to the combined mass of organic solvent (a) and organic solvent (c) of 100 parts by mass, the content of organic solvent (b) is preferably 10 to 200 parts by mass, more preferably 20 to 150 parts by mass, and even more preferably 40 to 100 parts by mass. When the content is within the above range, the compatibility between organic solvent (a) and organic solvent (c) is further improved, and the continuous discharge stability and low-temperature storage performance are superior.

[0165] The aforementioned organic solvents may also include other solvents (organic solvents) besides organic solvent (a), organic solvent (b), and organic solvent (c). The total content of organic solvents (a), (b), and (c) relative to 100% by mass is preferably 50% by mass or more, more preferably 70% by mass or more, further preferably 80% by mass or more, more preferably 90% by mass or more, and particularly preferably 95% by mass or more. When the content is 50% by mass or more, the dispersibility of the particles with the Ag and / or Cu powders and the compatibility with each organic solvent are superior, as are the continuous discharge stability, storage stability, and void formation inhibition during sintering.

[0166] When organic solvents (a), (b), and (c) are mixed in the proportions used in the bonding conductor paste described above, they preferably dissolve uniformly at room temperature without phase separation. Furthermore, in the bonding conductor paste described above, organic solvents (a), (b), and (c) preferably dissolve uniformly at room temperature without phase separation. Particularly, it is preferable that phase separation does not occur at 22–28°C (preferably 10–30°C, more preferably 0–35°C).

[0167] In the above paste, relative to the total of 100 parts by mass of the above particles, organic matter other than organic solvents, and Ag and / or Cu powders, the content of the above organic solvents is preferably 0.5 to 30 parts by mass or less, more preferably 2 to 20 parts by mass or less.

[0168] In addition, the paste preferably contains Ag and / or Cu powder in addition to the aforementioned particles. Specifically, when the particles contain Ag as the aforementioned metallic element X, Ag powder is preferred. When the particles contain Cu as the aforementioned metallic element X, Cu powder is preferred.

[0169] The average particle size (median particle size) of the Ag and / or Cu powders is preferably 0.1 to 100 μm, more preferably 0.3 to 50 μm, and even more preferably 0.5 to 10 μm. By having an average particle size of 0.1 μm or more, processing becomes easier. By having a particle size of 100 μm or less, bonding reliability is easily achieved.

[0170] The shape of the Ag and / or Cu powder is not particularly limited, and examples include spherical, flake-shaped (flat), and polyhedral shapes. Particles of the same shape can be used alone, or particles of different shapes can be used in combination. Among these, spherical shapes are preferred for proper dispersion in the paste.

[0171] The content of the Ag and / or Cu powder is preferably 5 to 2000 parts by mass, more preferably 20 to 1500 parts by mass, further preferably 30 to 1200 parts by mass, and particularly preferably 50 to 1000 parts by mass, relative to 100 parts by mass of the particles. By making the content of Ag and / or Cu powder 5 parts by mass or more, it can be fully bonded to the alloy particles during sintering, and by making it 2000 parts by mass or less, the coefficient of linear expansion is easily reduced.

[0172] In addition, the paste may contain other components besides those mentioned above. Examples of such other components include surfactants other than organic compounds and viscosity modifiers other than organic compounds. The content of these other components is preferably 5% by mass or less, and may also be 3% by mass or less, relative to 100% of the total amount of the organic compound.

[0173] [Precast components]

[0174] As one embodiment of the present invention, a preform comprising the above-described alloy can be cited. The preform refers to a material obtained by molding the above-described alloy, the above-described particles, the above-described alloy strip, or the above-described paste into a specific shape.

[0175] The shape of the aforementioned preform is not particularly limited, and can be in the form of sheet, sphere, ring, cylinder, strip, square, disc, washer, small piece, or line, etc., with sheet and sphere being particularly preferred.

[0176] [Sintered body]

[0177] As one embodiment of the present invention, the sintered body of the above alloy can be cited as an example. Figure 1 This is a magnified SEM image of the sintered body of the aforementioned alloy. Precipitations (nodules) of the aforementioned metallic element X can be confirmed on the surface of the sintered body. The sintered body can easily bond with nearby alloys and substrates through the precipitation of the aforementioned metallic element X.

[0178] [Manufacturing method of sintered body]

[0179] Furthermore, as one embodiment of the present invention, a method for manufacturing the sintered body of the above-mentioned alloy can be provided. As a method for manufacturing the sintered body, it can be produced by heat treatment of the alloy in a gaseous, liquid, or solid atmosphere in which a compound is to be formed with the metal element Y. More preferably, the heat treatment is performed in an oxygen atmosphere. When heat treatment is performed in an oxygen atmosphere, the oxygen concentration is preferably 0.01 to 30%, more preferably 0.05 to 25%, and even more preferably 0.1 to 21%. By setting the oxygen concentration to 0.01% or higher, the metal element Y can be oxidized, and the metal element X can be precipitated. Furthermore, by setting it to 30% or less, the oxidation rate of the metal element Y can be made moderate.

[0180] Furthermore, the heat treatment temperature (sintering temperature) is preferably 150~500℃, more preferably 180~450℃, and even more preferably 200~400℃. The heat treatment time (sintering time) is preferably, for example, 10 seconds to 2 hours, more preferably 3 minutes to 1 hour. Moreover, the sintered body can be a sintered body sintered without pressure or a sintered body sintered under pressure. In the case of pressure application, the pressure is, for example, 0.3~40 MPa.

[0181] [Assembly]

[0182] The sintered body described above can be used as a bonding body for joining materials together. For example, the preform can be coated or mounted between two materials to be joined, and organic matter can be volatilized by heating or the like as needed. Then, the preform is sintered by heating, pressurizing, or irradiating with active energy rays in the presence of oxygen to obtain a bonding body that joins the materials together. Examples of materials to be joined include substrates and electronic components. That is, it can be used for joining substrates together or for joining substrates with electronic components.

[0183] The thickness of the above-mentioned joint is preferably 5μm to 500μm, more preferably 20 to 300μm, and even more preferably 40 to 150μm.

[0184] [Electronic Components]

[0185] As one embodiment of the present invention, an electronic device comprising the above-described sintered body and / or the above-described bonding body can be cited. The electronic device is formed by bonding an object to a substrate via the above-described sintered body and / or the above-described bonding body. Figure 2 This is a schematic cross-sectional view of the electronic device. 1 represents the electronic device, 10 represents the substrate, 20 represents the bonding body, and 30 represents the object being bonded.

[0186] Examples of substrates include: metal substrates such as copper substrates, ceramic substrates, metal-ceramic substrates, SiC substrates, gallium nitride substrates, glass epoxy substrates, BT resin substrates, glass substrates, and resin substrates. Since the alloy of the present invention can be sintered at relatively low temperatures, substrates with low heat resistance can also be used. Ceramic substrates and metal-ceramic substrates are preferred as substrates, and copper-ceramic substrates and aluminum-ceramic substrates are more preferred.

[0187] Examples of the objects to be joined include electronic components and heat sinks. Examples of electronic components include semiconductor elements, LED elements, and other electronic components (chips, dies). Specifically, examples of semiconductor elements include power semiconductor elements. Furthermore, it is preferable that the bonding surface between the object to be joined and the bonding layer is silver-plated. Examples of materials for the objects to be joined include Si (silicon), SiC (silicon carbide), GaN, and diamond.

[0188] The aforementioned electronic devices can be manufactured by applying the alloy to a substrate using printing methods (specifically, distributor printing, mask printing, screen printing, inkjet printing, etc.), mounting the substrate on the coating layer, and then sintering it.

[0189] As for the sintering conditions, sintering can be carried out under the same conditions as those described in the above-described method for manufacturing sintered bodies.

[0190] Through the sintering process described above, the metallic element X in the alloy precipitates, thereby enabling strong bonding with the substrate and the bonded material. Therefore, electronic devices comprising the sintered body and / or bonded body can be easily formed and exhibit excellent bonding reliability.

[0191] The various methods disclosed in this specification can also be combined with any other features disclosed in this specification. Furthermore, the various configurations and combinations thereof in each embodiment are examples, and appropriate additions, omissions, and other modifications can be made without departing from the spirit of the invention. The invention is not limited to the embodiments, but only to the scope of the claims.

[0192] Example

[0193] Hereinafter, an embodiment of the present invention will be described in more detail based on an example.

[0194] Example 1

[0195] The silver (Ag) ingots (99.99% purity) were mixed to achieve a content of 84 mol% (95 mass%) and silicon (Si) ingots (99.9999% purity) to achieve 16 mol% (5 mass%), and then heated to 1450°C to melt the mixture. The resulting solution was quenched and pulverized using a gas atomizing device (trade name "RQP-20K", manufactured by Makabe Giken Co., Ltd.) to obtain alloy particles of Example 1 with an average particle size of 5 μm. It should be noted that in the alloy particles of Example 1, Si was dissolved in 5 mol of 100 mol of Ag.

[0196] Example 2

[0197] The mixture was prepared in a manner that achieved a silver (Ag) ingot purity of 99.99% (97% by mass) content of 89 mol% (97% by mass) and a silicon (Si) ingot purity of 99.9999% (3% by mass) content. Otherwise, it was pulverized using the same method as in Example 1. The alloy particles of Example 2 were obtained by classifying the average particle size to below 20 μm using an ultrasonic vibrating sieve (trade name "TSK-DGD type", manufactured by TOKYO-SCREEN Co., Ltd.). It should be noted that the alloy particles of Example 2 were confirmed to contain Si dissolved in Ag.

[0198] Example 3

[0199] The silver (Ag) ingots (99.99% purity) were mixed to achieve a content of 89 mol% (97 mass%) and silicon (Si) ingots (99.9999% purity) to achieve 11 mol% (3 mass%), and then heated to 1450°C to melt the mixture. The resulting solution was then quenched using a liquid quenching and solidification apparatus (trade name "RQP-20K", manufactured by Nisshin Giken Co., Ltd.) to produce the alloy strip of Example 3. It should be noted that it was confirmed that the alloy strip of Example 3 contained Si dissolved in Ag.

[0200] Comparative Example 1

[0201] The silver (Ag) ingots (99.99% purity) were mixed to achieve a content of 89 mol% (97 mass%) and silicon (Si) ingots (99.9999% purity) to achieve 11 mol% (3 mass%), and then heated to 1450°C to melt the mixture. The resulting solution was slowly cooled in a test tube to produce the ingot of Comparative Example 1. It should be noted that the presence of Si dissolved in Ag in the ingot of Comparative Example 1 was not confirmed.

[0202] [Table 1]

[0203]

[0204] [evaluate]

[0205] The raw materials from the examples and comparative examples were sintered for 1 hour under the conditions described in Table 2 to produce sintered bodies. It should be noted that sintering was carried out under conditions of 0% oxygen concentration and 100% nitrogen concentration to produce sintered bodies.

[0206] The above sintered bodies were photographed using SEM at 3000x magnification. Cases where nodules were confirmed on the surface were rated as ○, and cases where nodules were not confirmed were rated as ×. The results are recorded in Table 2.

[0207] [Table 2]

[0208]

[0209] It was confirmed that in the alloy of the embodiment, when heated in the presence of oxygen, metal element X precipitates on the surface. On the other hand, in the case where no phase of metal element Y is formed by the solidification of metal element X (Comparative Example 1), even when heated in the presence of oxygen, it was not confirmed that metal element X precipitates on the surface.

[0210] The following describes variations of the present invention.

[0211] [Postscript 1]

[0212] An alloy comprising a phase formed by a metal element Y dissolved in a metal element X, wherein the metal element X is precipitated on the surface by heat treatment in a gaseous, liquid, or solid atmosphere in which a compound is to be formed with the metal element Y.

[0213] [Postscript 2]

[0214] According to the alloy described in Appendix 1, the aforementioned metallic element X is precipitated on the surface by heat treatment in a gaseous atmosphere.

[0215] [Postscript 3]

[0216] According to the alloy described in Appendix 1 or 2, the aforementioned metallic element X is precipitated on the surface by heat treatment in an oxygen atmosphere.

[0217] [Postscript 4]

[0218] According to any one of Appendix 1 to 3, in the alloy, the phase that has undergone the above-mentioned solid solution exists on the surface of the alloy.

[0219] [Postscript 5]

[0220] The alloy according to any one of Appendices 1 to 4, wherein the proportion of the phase in which the above-mentioned solid solution has occurred in the entire surface (100%) of the alloy is 10% or more.

[0221] [Postscript 6]

[0222] According to any one of Appendices 1 to 5, the proportion of the phase that has undergone the above-mentioned solid solution in 100% by mass of the total amount of the alloy is 3% by mass or more.

[0223] [Postscript 7]

[0224] The alloy according to any one of Appendices 1 to 6, wherein the aforementioned metallic element X is Ag and / or Cu.

[0225] [Postscript 8]

[0226] According to the alloy described in Appendix 7, wherein the aforementioned metallic element X comprises Ag and the aforementioned metallic element Y comprises Si and / or Ge.

[0227] [Postscript 9]

[0228] According to the alloy described in Appendix 7, wherein the aforementioned metallic element X comprises Cu, and the aforementioned metallic element Y comprises W and / or Cr.

[0229] [Postscript 10]

[0230] The alloy according to any one of Appendices 1 to 9 contains the aforementioned metallic element Y as a supersaturated solid solution of the aforementioned metallic element X.

[0231] [Postscript 11]

[0232] In any one of the appendices 1 to 10, the molar ratio of the metal element X to the metal element Y [metal element X / metal element Y] is 95 / 5 to 10 / 90.

[0233] [Postscript 12]

[0234] According to any one of the appendices 1 to 11, in the alloy of the above alloy, the content of the above metal element X in 100% by mass is preferably 1 to 99% by mass, more preferably 10 to 98% by mass, and even more preferably 50 to 97% by mass.

[0235] [Postscript 13]

[0236] According to any one of Appendix 1 to 12, in the alloy, the content of the metal element Y in 100% by mass of the alloy is preferably 1 to 99% by mass, more preferably 2 to 90% by mass, and even more preferably 3 to 50% by mass.

[0237] [Postscript 14]

[0238] A particle comprising any one of the alloys described in Appendix 1 to 13.

[0239] [Postscript 15]

[0240] According to Appendix 14, the particles have an average particle size of 0.1 to 100 μm.

[0241] [Postscript 16]

[0242] An alloy strip comprising any one of the alloys described in Appendix 1 to 13.

[0243] [Postscript 17]

[0244] The alloy strip described in Appendix 16 has a thickness of 1 μm to 2 mm.

[0245] [Postscript 18]

[0246] According to Appendix 16 or 17, the alloy strip has a width of 0.1 to 100 mm.

[0247] [Postscript 19]

[0248] A paste comprising the particles described in Appendix 14 or 15, organic matter, and Ag powder and / or Cu powder.

[0249] [Postscript 20]

[0250] A preform comprising any one of the alloys described in Annexes 1 to 13.

[0251] [Postscript 21]

[0252] According to Appendix 20, the preform is in sheet or spherical form.

[0253] [Postscript 22]

[0254] A sintered body, which is a sintered body of the alloy described in any one of Appendices 1 to 13.

[0255] [Postscript 23]

[0256] A joint comprising the sintered body described in Appendix 22.

[0257] [Postscript 24]

[0258] A substrate comprising the bonding body described in Appendix 23.

[0259] [Postscript 25]

[0260] An electronic device comprising the junction described in Appendix 23 or 24.

[0261] [Postscript 26]

[0262] A method for manufacturing a sintered body, comprising: a step of heat-treating the alloy as described in any one of Appendices 1 to 13 in a gaseous, liquid, or solid atmosphere in which a compound is to be formed with the metal element Y.

[0263] [Postscript 27]

[0264] The method for manufacturing the sintered body according to Appendix 26 includes a step of heat treatment in an oxygen atmosphere.

[0265] [Postscript 28]

[0266] According to the method for manufacturing the sintered body described in Appendix 27, the oxygen concentration during the heat treatment is 0.01~30%.

Claims

1. An alloy comprising a phase formed by the solid solution of metallic element Y in metallic element X, in, The metal element X is precipitated on the surface by heat treatment in a gaseous, liquid, or solid atmosphere in which it is to form a compound with the metal element Y.

2. The alloy according to claim 1, wherein, The metal element X is precipitated on the surface by heat treatment in an oxygen atmosphere.

3. The alloy according to claim 1 or 2, wherein, The metallic element X is Ag and / or Cu.

4. The alloy according to claim 3, wherein, The metal element X contains Ag, and the metal element Y contains Si and / or Ge.

5. The alloy according to claim 3, wherein, The metal element X contains Cu, and the metal element Y contains W and / or Cr.

6. The alloy according to claim 1 or 2, comprising the metal element Y as a supersaturated solid solution of the metal element X.

7. The alloy according to claim 1 or 2, wherein, The molar ratio of metal element X to metal element Y [metal element X / metal element Y] is 95 / 5 to 10 / 90.

8. A particle comprising the alloy of claim 1 or 2.

9. The particles according to claim 8, wherein the average particle size is 0.1~100 μm.

10. An alloy strip comprising the alloy of claim 1 or 2.

11. A paste comprising: The particles of claim 8 Organic matter, and Ag powder and / or Cu powder.

12. A preform comprising the alloy of claim 1 or 2.

13. The preform according to claim 12, wherein it is in sheet or spherical shape.

14. A sintered body, which is a sintered body of the alloy according to claim 1 or 2.

15. A joint comprising the sintered body of claim 14.

16. A substrate comprising the bonding body of claim 15.

17. An electronic device comprising the junction of claim 15.

18. A method for manufacturing a sintered body, comprising: The process of heat-treating the alloy according to claim 1 or 2 in a gaseous, liquid, or solid atmosphere in which a compound is to be formed with the metallic element Y.

19. The method for manufacturing a sintered body according to claim 18, comprising: The process of heat treatment in an oxygen atmosphere.

20. The method for manufacturing a sintered body according to claim 19, wherein, The oxygen concentration during the heat treatment is 0.01~30%.

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