JP2020045514A - Method for producing joined body, copper paste for forming sintered copper pillar, and pillar-fitted member for joining - Google Patents

Abstract

To provide a copper paste for forming a sintered copper pillar capable of efficiently forming a pillar for joining capable of improving joining reliability and reducing electromigration at high precision, a method for producing a joined boy capable of obtaining a joined body having sufficient joining strength using the copper paste, and a piller-fitted member for joining.SOLUTION: A method for producing a joined body comprising a process of producing a joined body having a first member, a second member and a sintered copper pillar for joining the first member and the second member includes a process where a piller precursor arranged between the first member and the second member is sintered to form a sintered copper piller. The pillar precursor includes metal particles and an organic dispersion medium, and the metal particles include copper particles.SELECTED DRAWING: None

Description

  The present invention relates to a method for manufacturing a joined body, a copper paste for forming a sintered copper pillar, and a member with a pillar for joining.

  Generally, solder bonding is used for electrical bonding in an electronic device. For example, in flip chip bonding of a micro device, a solder ball or a solder paste is used for bonding a micro device and an electrode pad on a substrate.

  In recent years, in flip chip bonding, a method has been used in which metal pillars are formed on a microdevice and the metal pillars and electrode pads on a substrate are soldered together with the narrower pitch of terminals. However, in the solder joining, (1) Kirkendall voids occur between the solder and the electrode pad and between the solder and the metal pillar. (2) When the reflow process is performed again after the joining, (3) signal reflection occurs due to impedance mismatch at the interface between dissimilar metals.

  On the other hand, a method of joining using a metal other than solder has been studied. For example, in Patent Literature 1 below, a copper pillar provided on a microdevice and a copper pad on a substrate are bonded using a bonding agent (copper paste) in which copper microparticles and copper nanoparticles are mixed. A method has been proposed.

  However, even in the above method, it is necessary to form copper pillars on the device in advance. Copper pillars are mainly formed by electrolytic plating, and there is a problem that it takes time to form pillars. There is also a problem that when the plating speed is set to be high, the variation in height becomes large.

  Methods for forming metal pillars by a method other than electrolytic plating are being studied. For example, Patent Literature 2 below discloses a method in which a low-melting metal powder is melted using a paste in which a high-melting metal powder, a low-melting metal powder, and a binder are mixed to form a metal pillar itself, and bonding performed by the method. The body has been proposed.

U.S. Patent Application Publication No. 2016/0351529 JP-A-2006-115846

  In the method described in Patent Document 2, a low-melting-point alloy and a solder alloy are used as the low-melting-point metal powder. There is a problem of migration. Another problem is that when pillars are formed on a copper lead frame, interface peeling may occur due to a difference in thermal expansion coefficient.

  The present invention provides a sintered copper pillar-forming copper paste capable of efficiently and accurately forming a bonding pillar capable of improving connection reliability and reducing electromigration, and using such a copper paste. It is an object of the present invention to provide a method for manufacturing a joined body for obtaining a joined body having sufficient joining strength by using a method and a member with a joining pillar.

  In order to solve the above-mentioned problems, the present invention is a method for manufacturing a joined body including a first member, a second member, and a sintered copper pillar for joining the first member and the second member. Forming a sintered copper pillar by sintering a pillar precursor disposed between the first member and the second member, wherein the pillar precursor comprises metal particles, an organic dispersion medium, And a method for producing a joined body in which metal particles contain copper particles.

  According to the method for manufacturing a joined body of the present invention, by sintering a pillar precursor containing the above components, a sintered copper pillar having excellent connection reliability and less likely to cause electromigration is formed efficiently and accurately. be able to. Then, by joining the members by such a sintered copper pillar, a joined body having sufficient joining strength can be obtained. In addition, even when the member is a copper lead frame, it is possible to sufficiently suppress interfacial peeling due to a difference in thermal expansion coefficient.

  It is preferable that the copper particles include sub-micro copper particles having a volume average particle diameter of 0.01 μm or more and less than 0.8 μm from the viewpoint that it is easy to secure bonding strength and connection reliability.

  In the method for producing a joined body of the present invention, the content of copper contained in the sintered copper pillar is such that the sintered copper pillar having excellent thermal conductivity and electric conductivity is easily formed. 96% by mass or more based on the total mass of components constituting the pillars (excluding carbon, oxygen, and nitrogen), and the volume ratio of copper in the sintered copper pillars is 50% by volume or more. Is preferred.

  The sintered copper pillar has a shortest distance H between the joint surface with the first member and the joint surface with the second member of 5 to 200 μm, and a minimum diameter W of 10 to 10 in a cross section perpendicular to the direction in which the pillar extends. The ratio of H to W (H / W) may be from 0.01 to 4.0 at 500 μm.

  The first member and / or the second member has at least one metal selected from the group consisting of copper, nickel, silver, platinum, gold, and palladium on a bonding surface with the sintered copper pillar. It may be.

  The method for manufacturing a joined body according to the present invention is a method for obtaining a joined body having a shear strength of 4 MPa or more between a first member and / or a second member having the above-described metal on a joint surface and a sintered copper pillar. It may be.

  In the method for manufacturing a joined body of the present invention, a copper paste containing metal particles and an organic dispersion medium is formed into a pillar shape by screen printing or stencil printing on the first member, and then the second member is mounted. By doing so, a pillar precursor can be provided between the first member and the second member.

  The pillar-shaped copper paste has a height of 10 to 200 μm, a maximum diameter of the wetting spread on the first member side of 50 μm or less, and an indentation depth of 50 μm or less when the second member is mounted. You may.

  In the method for manufacturing a joined body of the present invention, the joined body is a micro device as a first member, a substrate having an electrode as a second member, and a sintered copper pillar for electrically joining the micro device and the electrode. An electronic device comprising:

  In this case, the method for manufacturing a joined body of the present invention may further include a step of filling a resin around the sintered copper pillar.

  The present invention is also a copper paste for forming a sintered copper pillar for joining members, wherein the copper paste contains metal particles and an organic dispersion medium, and the metal particles have a volume average particle size. Sub-micro copper particles of 0.01 μm or more and less than 0.8 μm are contained at a ratio of 30% by mass or more and 100% by mass or less based on the total mass of the metal particles, and the content of the organic dispersion medium is the total mass of the copper paste. The present invention provides a copper paste for forming a sintered copper pillar in an amount of 5% by mass or more and 70% by mass or less on the basis of:

  According to the copper paste for forming a sintered copper pillar of the present invention, by having the above-described configuration, it is possible to efficiently and accurately form a bonding pillar capable of improving connection reliability and reducing electromigration. .

  The metal particles may further include micro copper particles having a volume average particle diameter of 0.8 μm or more and 50 μm or less at a ratio of more than 0% by mass and 50% by mass or less based on the total mass of the metal particles. In this case, it is possible to reduce the volume shrinkage and the occurrence of voids when sintering the copper paste or the pillar precursor formed into the pillar shape, and it is easy to secure the joining strength of the joined body joined by the sintered copper pillar. Becomes

  The copper paste for forming a sintered copper pillar of the present invention preferably has a viscosity at 25 ° C. of 50 to 2000 Pa · s and a thixotropy index of 2.0 to 20 measured in accordance with JIS Z3284. In this case, it becomes easy to form the copper paste into a pillar shape by various printing methods, and it is possible to suppress the printed copper paste from spreading excessively.

  The present invention also includes a member having a metal layer and a pillar provided on the metal layer, and a member with a pillar for joining joined to another member via the pillar, wherein the pillar is made of sintered copper. And the content of copper contained in the pillar is 96% by mass or more based on the total mass of the components constituting the pillar (excluding carbon, oxygen and nitrogen), and the volume ratio of copper in the pillar is Is 50% by volume or more.

  The joining pillar made of sintered copper and having the above configuration can be formed in a shorter time than electrolytic plating, is excellent in shortened thermal conductivity and electric conductivity, and is less likely to cause electromigration. According to the member with a pillar for joining of the present invention including such pillars, it is easy to ensure the connection reliability of a joined body obtained by joining to another member, and the manufacturing process of the joined body can be shortened. Time can be saved.

  The member with a pillar for joining of the present invention preferably has a shear strength between the pillar and the metal layer of 4 MPa or more.

  According to the present invention, a copper paste for forming a sintered copper pillar capable of efficiently and accurately forming a bonding pillar capable of improving connection reliability and reducing electromigration, and such a copper paste To provide a method for manufacturing a joined body to obtain a joined body having sufficient joining strength, and a member with a pillar for joining.

  According to the copper paste for forming a sintered copper pillar according to the present invention, the bonding pillar can be formed in a shorter time than the electrolytic plating method, and therefore, the productivity of the bonded body can be improved. Further, the sintered copper pillar formed using the copper paste for forming a sintered copper pillar of the present invention is less likely to cause electromigration, and has a difference in thermal expansion coefficient even when the member to be joined is a copper lead frame. Therefore, it is possible to sufficiently suppress the interface peeling due to the above, so that it is easier to secure the connection reliability in the electrical joining of the electronic device than in the solder joining.

It is a schematic cross section showing one embodiment of a joined object concerning the present invention. It is a schematic cross section for explaining one Embodiment of the manufacturing method of the joined object concerning the present invention. It is a schematic cross section for explaining one Embodiment of the manufacturing method of the joined object concerning the present invention. It is a schematic cross section for explaining one Embodiment of the manufacturing method of the joined object concerning the present invention. It is a schematic cross section which shows one Embodiment of the member with a pillar for joining which concerns on this invention.

  Hereinafter, embodiments for carrying out the present invention will be described in detail. However, the present invention is not limited to the following embodiments. In the following embodiments, the constituent elements (including element steps and the like) are not essential unless otherwise specified, and unless it is deemed essential in principle. The same applies to numerical values and their ranges, and does not limit the present invention.

  In the present specification, the term “step” is included in the term as well as an independent step, even if it cannot be clearly distinguished from other steps as long as the purpose of the step is achieved. In this specification, a numerical range indicated by using “to” indicates a range including numerical values described before and after “to” as a minimum value and a maximum value, respectively. In the present specification, the content of each component in the composition, if there are a plurality of substances corresponding to each component in the composition, unless otherwise specified, the total of the plurality of substances present in the composition Means quantity.

[Joint body]
FIG. 1 is a schematic cross-sectional view for explaining one embodiment of a joined body according to the present invention. A joint body 10 shown in FIG. 1 includes a first member 1, a second member 2, and a sintered copper pillar 3 for joining the first member 1 and the second member 2.

  The lower surface and the upper surface of the sintered copper pillar form a bonding surface with the first member and a bonding surface with the second member, respectively, and they are bonded by metal bonding. By forming such a metal bond, the joined body can be firmly joined with low electric resistance.

  Examples of the first member 1 and the second member 2 include an active or passive electronic device, a wiring board on which the electronic device is mounted, a package having an electronic device and a redistribution layer provided on the electronic device, and the like. .

  Examples of the electronic device include a coil, a capacitor, a SAW filter, a power IC, a logic chip, a memory chip, a sensor, a piezoelectric element, a transistor, a diode, and the like.

  Examples of the wiring board include a mounting substrate, a lead frame such as a copper lead frame, a ceramic substrate, a resin molded product having a printed metal wiring such as a MID (Molded Interconnect Device, molded circuit component), a package having a rewiring layer, and the like. .

  One of the first member and the second member may be an active or passive electronic device, and the other may be a wiring board on which the electronic device is mounted. In this case, it is possible to mount the electronic device with excellent reliability.

  Further, both the first member and the second member may be a package having an electronic device and a rewiring layer provided on the electronic device. In this case, highly reliable package-on-package mounting becomes possible.

  The first member and / or the second member has at least one metal selected from the group consisting of copper, nickel, silver, platinum, gold, and palladium on a bonding surface with the sintered copper pillar. You may. These metals can reduce and remove the oxide film on the surface under a reducing atmosphere such as hydrogen or formic acid at a sintering temperature of 300 ° C. or less. Therefore, the joined body can have high joining strength due to metal bonding between the exposed metal surface of the member and the sintered copper pillar. The above metal may be provided as a metal film or a sintered metal layer on the first member and / or the second member.

  The sintered copper pillar preferably has a copper content of 96% by mass or more based on the total mass of components (excluding carbon, oxygen, and nitrogen) constituting the sintered copper pillar, It is more preferably at least 0.5% by mass, and even more preferably at least 97% by mass. The above-mentioned carbon, oxygen, and nitrogen are components that may be randomly included in the sintered copper pillar due to filling of an underfill by mounting or filling of a sealing material.

  When the content of copper in the sintered copper pillar is within the above range, it becomes easy to form the sintered copper pillar by printing and sintering a copper paste for forming a sintered copper pillar described below, and to secure the bonding strength and obtain the electro-resistance. This is advantageous in terms of suppressing migration. Further, when the bonding surface contains copper, the bonding is made of the same kind of metal, so that it is easy to suppress the occurrence of Kirkendall voids, and a bonded body with even more excellent connection reliability can be obtained.

  From the viewpoint of thermal conductivity and electric conductivity, the volume ratio of copper in the sintered copper pillar is preferably 50% by volume or more, more preferably 60% by volume or more. More preferably, it is at least volume%. The larger the volume ratio of copper in the sintered copper pillar, the higher the thermal conductivity and electrical conductivity of the sintered copper pillar, which is preferable. In this specification, portions other than copper of the sintered copper pillar are expressed as holes. However, when a resin component such as a filler or an underfill is contained in the pores, the volume of the component is also included as the volume of the pores. The volume ratio of copper in the sintered copper pillar can be determined from the SEM image of the cross section of the sintered copper pillar.

  In the sintered copper pillar, the shortest distance H between the joint surface with the first member and the joint surface with the second member (sometimes referred to as the “height of the sintered copper pillar”) is 5 to 200 μm. May be 10 to 150 μm, or 20 to 100 μm.

  The sintered copper pillar has a minimum diameter W (sometimes referred to as “width (diameter) of the sintered copper pillar)” in a cross section perpendicular to the direction in which the pillar extends, and may be 10 to 500 μm, or 25 to 300 μm. And may be 50 to 150 μm.

  In the sintered copper pillar, the ratio (H / W) of the above H and the above W (sometimes referred to as “cross-sectional aspect ratio of the sintered copper pillar”) may be 0.01 to 4.0. 0.1 to 2.5, or 0.15 to 2.0.

  The above H and the above W can be obtained from the SEM image of the cross section of the sintered copper pillar.

  In the joined body of the present embodiment, the shear strength between the joint surface of the first member and / or the second member and the sintered copper pillar can be 4 MPa or more, and may be 10 MPa or more. , 20 MPa or more. At this time, the joining surface of the first member and / or the second member can include the above-described metal, and may include the above-described metal as a metal layer.

  For the shear strength, for example, using a bonding strength test device, the tool of the device pushes the sintered copper pillar horizontally at a constant speed, and the maximum strength when the joint surface between the sintered copper pillar and the member is peeled is the cross-sectional area of the pillar It can be calculated by dividing by.

[Method of manufacturing bonded body]
The method for manufacturing a joined body according to the present embodiment is a method for manufacturing the joined body according to the above-described embodiment, and includes sintering a pillar precursor disposed between the first member and the second member. And thereby forming a sintered copper pillar. The pillar precursor contains metal particles and an organic dispersion medium, and the metal particles can include copper particles.

  In this embodiment, after forming a copper paste (copper paste for forming a sintered copper pillar) into a pillar shape by printing on the first member, the first member and the second member are mounted by mounting the second member. A pillar precursor can be provided between the second member and the second member.

<Copper paste for forming sintered copper pillars>
The copper paste for forming a sintered copper pillar according to the present embodiment contains metal particles and an organic dispersion medium, and the metal particles include copper particles.

  Examples of the copper particles include sub-micro copper particles and micro copper particles. The sub-micro copper particles refer to copper particles having a particle size of 0.01 μm or more and less than 0.8 μm. Micro copper particles refer to copper particles having a particle size of 0.8 μm or more and less than 50 μm.

  The copper paste of the present embodiment contains sub-micro copper particles, and may further contain other metal particles other than the micro copper particles and / or the copper particles, if necessary.

(Sub-micro copper particles)
As the sub-micro copper particles, copper particles having sinterability in a temperature range of 150 ° C. or more and 300 ° C. or less can be used. Examples of the sub-micro copper particles include those containing copper particles having a particle diameter of 0.01 μm or more and less than 0.8 μm, for example, copper particles having a volume average particle diameter of 0.01 μm or more and less than 0.8 μm. Can be used. When the volume average particle diameter of the sub-micro copper particles is 0.01 μm or more, it is easy to obtain effects such as suppression of the synthesis cost of the sub-micro copper particles, good dispersibility, and suppression of the use amount of the surface treatment agent. When the volume average particle diameter of the sub-micro copper particles is less than 0.8 μm, the effect that the sinterability of the sub-micro copper particles is excellent is easily obtained. From the viewpoint of exhibiting the above effect even more, the upper limit of the volume average particle diameter of the sub-micro copper particles may be 0.6 μm or less, may be 0.5 μm or less, and 0.4 μm or less. Is also good. The lower limit of the volume average particle size of the sub-micro copper particles may be 0.02 μm or more, 0.05 μm or more, or 0.1 μm or more. The volume average particle diameter of the sub-micro copper particles may be, for example, 0.01 μm or more and 0.5 μm or less, or may be 0.12 μm or more and less than 0.8 μm, or 0.15 μm or more and less than 0.8 μm. May be 0.15 μm or more and 0.6 μm or less, 0.2 μm or more and 0.5 μm or less, or 0.3 μm or more and 0.45 μm or less.

  In addition, in this specification, a volume average particle diameter means 50% volume average particle diameter. When determining the volume average particle size of copper particles, a light scattering method particle size distribution measurement is performed by dispersing a copper particle as a raw material or a dry copper particle obtained by removing a volatile component from a copper paste in a dispersion medium using a dispersant. It can be determined by a method using a device (for example, a Shimadzu nanoparticle size distribution measuring device (SALD-7500nano, manufactured by Shimadzu Corporation)) or the like. When a light scattering particle size distribution analyzer is used, hexane, toluene, α-terpineol, 4-methyl-1,3-dioxolan-2-one, or the like can be used as a dispersion medium.

  The shape of the sub-micro copper particles is not particularly limited. Examples of the shape of the sub-micro copper particles include a sphere, a lump, a needle, a column, a flake, a substantially sphere, and an aggregate thereof. From the viewpoint of dispersibility and filling properties, the shape of the sub-micro copper particles may be spherical, substantially spherical, or flake-like, and from the viewpoint of combustibility, dispersibility, mixability with flake-like micro particles, etc. Or it may be substantially spherical. In the present specification, the “flake shape” includes a flat shape such as a plate shape and a scale shape.

  The sub-micro copper particles may have an aspect ratio of 5 or less or 3 or less from the viewpoint of dispersibility, filling properties, and mixing with the flake-like micro particles. In the present specification, the “particle aspect ratio” indicates the long side / thickness of the particle. The measurement of the long side and the thickness of the particle can be obtained, for example, from an SEM image of the particle.

  The sub-micro copper particles may be treated with a specific surface treatment agent. Specific surface treatment agents include, for example, organic acids having 2 to 18 carbon atoms. Examples of the organic acid having 2 to 18 carbon atoms include acetic acid, propanoic acid, butanoic acid, pentanoic acid, hexanoic acid, heptanoic acid, caprylic acid, methylheptanoic acid, ethylhexanoic acid, propylpentanoic acid, pelargonic acid, and methyloctane. Acid, ethylheptanoic acid, propylhexanoic acid, capric acid, methylnonanoic acid, ethyloctanoic acid, propylheptanoic acid, butylhexanoic acid, undecanoic acid, methyldecanoic acid, ethylnonanoic acid, propyloctanoic acid, butylheptanoic acid, lauric acid, methylundecane Acid, ethyldecanoic acid, propylnonanoic acid, butyloctanoic acid, pentylheptanoic acid, tridecanoic acid, methyldodecanoic acid, ethylundecanoic acid, propyldecanoic acid, butylnonanoic acid, pentyloctanoic acid, myristic acid, methyltridecanoic acid, ethyldodeca Acid, propylundecanoic acid, butyldecanoic acid, pentylnonanoic acid, hexyloctanoic acid, pentadecanoic acid, methyltetradecanoic acid, ethyltridecanoic acid, propyldodecanoic acid, butylundecanoic acid, pentyldecanoic acid, hexylnonanoic acid, palmitic acid, methylpentadecanoic acid, Ethyltetradecanoic acid, propyltridecanoic acid, butyldodecanoic acid, pentylundecanoic acid, hexyldecanoic acid, heptylnonanoic acid, heptadecanoic acid, octadecanoic acid, methylcyclohexanecarboxylic acid, ethylcyclohexanecarboxylic acid, propylcyclohexanecarboxylic acid, butylcyclohexanecarboxylic acid, pentyl Cyclohexanecarboxylic acid, hexylcyclohexanecarboxylic acid, heptylcyclohexanecarboxylic acid, octylcyclohexanecarboxylic , Saturated fatty acids such as nonylcyclohexanecarboxylic acid; octenoic acid, nonenoic acid, methylnonenoic acid, decenoic acid, undecenoic acid, dodecenoic acid, tridecenoic acid, tetradecenoic acid, myristoleic acid, pentadecenoic acid, hexadecenoic acid, palmitoleic acid, sabienoic acid, Unsaturated fatty acids such as oleic acid, vaccenic acid, linoleic acid, linoleic acid, and linolenic acid; terephthalic acid, pyromellitic acid, o-phenoxybenzoic acid, methylbenzoic acid, ethylbenzoic acid, propylbenzoic acid, butylbenzoic acid, pentyl And aromatic carboxylic acids such as benzoic acid, hexyl benzoic acid, heptyl benzoic acid, octyl benzoic acid, and nonyl benzoic acid. One type of organic acid may be used alone, or two or more types may be used in combination. By combining such an organic acid with the above-mentioned sub-micro copper particles, there is a tendency that both dispersibility of the sub-micro copper particles and desorption of the organic acid during sintering can be compatible.

  The treatment amount of the surface treating agent may be 0.07% by mass or more and 2.1% by mass or less, 0.10% by mass or more and 1.6% by mass or less, and 0.2% by mass or more. It may be 1.1% by mass or less.

  Commercially available sub-micro copper particles can be used. Examples of commercially available sub-micro copper particles include CH-0200 (manufactured by Mitsui Kinzoku Mining Co., Ltd., volume average particle size 0.36 μm) and HT-14 (manufactured by Mitsui Kinzoku Mining Co., Ltd .; 41 μm), CT-500 (manufactured by Mitsui Kinzoku Mining Co., Ltd., volume average particle size 0.72 μm), Tn-Cu100 (manufactured by Taiyo Nissan Co., volume average particle size 0.12 μm), Cu-C-40 (Fukuda metal foil) Powder industry, volume average particle size 0.2 μm).

  The content of the sub-micro copper particles may be 30% by mass or more and 100% by mass or less, 40% by mass or more and 90% by mass or less, or 50% by mass or more based on the total mass of the metal particles. It may be 80% by mass or less. When the content of the sub-micro copper particles is within the above range, it becomes easy to secure the joining strength of the joined body obtained by sintering the pillar precursor formed by the copper paste, and the members of the joined body are micro-sized. If it is a device, the microdevice tends to exhibit good die shear strength and connection reliability.

  From the viewpoint of promoting sintering, good connection between the first member and the second member, and manifesting low-temperature sinterability, the content of the sub-micro copper particles is not less than 20% by mass and not less than 95% by mass based on the total amount of the copper paste. It may be not more than 30% by mass, not more than 30% by mass and not more than 85% by mass, or may be not less than 40% by mass and not more than 75% by mass.

(Micro copper particles)
As the micro copper particles, copper particles having a particle diameter of 0.8 μm or more and 50 μm or less can be used. For example, copper particles having a volume average particle diameter of 0.8 μm or more and 50 μm or less can be used.

  The micro copper particles are preferably blended in combination with the sub-micro copper particles. In this case, it is possible to reduce the volume shrinkage and the occurrence of voids when the pillar precursor formed by the copper paste is sintered, and it is easy to secure the joining strength of the joined body obtained by sintering the pillar precursor. When the member of the joined body is a micro device, the micro device tends to exhibit good die shear strength and connection reliability. From the viewpoint of exhibiting the above effect even more, the volume average particle diameter of the micro copper particles may be 0.8 μm or more and 20 μm or less, 0.8 μm or more and 10 μm or less, or 2 μm or more and 20 μm or less. The thickness may be 2 μm or more and 10 μm or less, 3 μm or more and 20 μm or less, or 3 μm or more and 10 μm or less.

  The shape of the micro copper particles is not particularly limited. Examples of the shape of the micro copper particles include a sphere, a lump, a needle, a flake, a substantially sphere, and an aggregate thereof.

  In the present embodiment, flake-like micro copper particles can be combined with sub-micro copper particles. In this case, the micro copper particles in the pillar precursor are oriented substantially parallel to the bonding surface, so that volume shrinkage in the bonding surface direction when the pillar precursor is sintered can be suppressed, and the pillar precursor is fired. It becomes easy to secure the joining strength of the joined body obtained by tying. When the member of the joined body is a micro device, the micro device tends to show good die shear strength and connection reliability. In light of the further effect, the aspect ratio of the flake-shaped micro copper particles is preferably 3 or more, more preferably 4 or more, and still more preferably 6 or more.

  The presence or absence of the treatment with the surface treatment agent in the micro copper particles is not particularly limited. From the viewpoints of dispersion stability and oxidation resistance, the micro copper particles may be treated with a surface treatment agent. The surface treatment agent may be removed during bonding. Examples of such surface treatment agents include aliphatic carboxylic acids such as dodecanoic acid, palmitic acid, heptadecanoic acid, stearic acid, arachidic acid, linoleic acid, linoleic acid, and oleic acid; terephthalic acid, pyromellitic acid, o- Aromatic carboxylic acids such as phenoxybenzoic acid; aliphatic alcohols such as cetyl alcohol, stearyl alcohol, isobornylcyclohexanol, and tetraethylene glycol; aromatic alcohols such as p-phenylphenol; octylamine, dodecylamine, stearylamine and the like Alkylamines; aliphatic nitriles such as stearonitrile and decanitrile; silane coupling agents such as alkylalkoxysilanes; and high-molecular-weight compounds such as polyethylene glycol, polyvinyl alcohol, polyvinylpyrrolidone, and silicone oligomers. Treating material and the like. One type of surface treatment agent may be used alone, or two or more types may be used in combination.

  Commercially available micro copper particles can be used. Examples of commercially available flake-shaped micro copper particles include, for example, MA-C025KFD (manufactured by Mitsui Kinzoku Mining Co., Ltd., volume average particle size 7.5 μm), 4L3N (Fukuda Metal Foil Powder Co., Ltd., volume average particle size) 3.0 μm), 3L3N (Fukuda Metal Foil & Powder Industry Co., Ltd., volume average particle size 5.7 μm), 3L3 (Fukuda Metal Foil Powder Co., Ltd., volume average particle size 8.0 μm), 2L3N (Fukuda Metal Foil) Powder Industry Co., Ltd., volume average particle size 9.9 μm), 1110F (Mitsui Metal Mining Co., Ltd., volume average particle size 3.8 μm), 1050YP (Mitsui Metal Mining Co., Ltd., volume average particle size 0.94 μm) 1100YP (Mitsui Metal Mining Co., Ltd., volume average particle size 1.2 μm), 1200 YP (Mitsui Metal Mining Co., Ltd., volume average particle size 3.4 μm), 1400 YP (Mitsui Metal Mining Co., Ltd.) Ltd., volume average particle size 5.2 .mu.m) and the like.

  Examples of the spherical or substantially spherical micro copper particles include 1050Y (Mitsui Metal Mining Co., Ltd., volume average particle size 0.81 μm), 1100Y (Mitsui Metal Mining Co., Ltd., volume average particle size 1.1 μm), 1200Y 1300Y (Mitsui Metal Mining Co., Ltd., volume average particle size 4.6 μm), 1400Y (Mitsui Metal Mining Co., Ltd., volume average particle size 5. 5 μm), 1200 YM (Mitsui Metal Mining Co., Ltd., volume average particle size 1.9 μm), 1300 YM (Mitsui Metal Mining Co., Ltd., volume average particle size 3.4 μm), 1400 YM (Mitsui Metal Mining Co., Ltd., volume average) Particle size 4.2 μm), Cu-HWQ 1.5 μm (Fukuda Metal Foil & Powder Co., Ltd., volume average particle size 1.5 μm), Cu-HWQ 1.5 μm (Fukuda Metal Foil Powder Co., Ltd.) Co., Ltd., volume average particle size 1.4 μm), Cu-HWQ 3.0 μm (Fukuda Metal Foil Powder Industry Co., Ltd., volume average particle size 3.0 μm), Cu-HWQ 5.0 μm (Fukuda Metal Foil Powder Industry) Co., Ltd., volume average particle size 4.1 μm), and Cu-HWQ 10 μm (Fukuda Metal Foil Powder Industry Co., Ltd., volume average particle size 9.4 μm).

  The content of the micro copper particles is preferably from 0% by mass to 70% by mass, more preferably from 5% by mass to 50% by mass, and more preferably from 10% by mass to 40% by mass, based on the total mass of the metal particles. Is more preferable.

  The copper paste of the present embodiment is obtained by mixing micro copper particles having a volume average particle diameter of 0.8 μm or more and 50 μm or less, preferably 2 μm or more and 50 μm or less with 0 mass% based on the total mass of the metal particles. It can be contained in a proportion of not more than 50% by mass. In this case, it is possible to reduce the volume shrinkage and the occurrence of voids when sintering the copper paste formed into the pillar shape, and it is easy to secure the joining strength of the joined body joined by the sintered copper pillar.

  When blending the flaky micro copper particles, the content of the flaky micro copper particles is preferably 0% by mass or more and 70% by mass or less based on the total mass of the metal particles from the viewpoint of effectively obtaining the effects described above. It is more preferably 5% by mass or more and 50% by mass or less, further preferably 10% by mass or more and 40% by mass or less. From the viewpoint of suppressing the occurrence of cracks while sufficiently securing the strength of the sintered copper pillar, Particularly preferred is 20% by mass to 40% by mass.

  In addition, while suppressing the variation in the height of the pillar precursor, from the viewpoint of suppressing the occurrence of cracks in the sintered copper pillar and sufficiently securing the bonding strength, the content of the flake-shaped micro copper particles is determined by the content of the metal particles. It is preferably from 20% by mass to 40% by mass based on the total mass.

  The copper paste of the present embodiment may include copper nanoparticles as long as the effects of the micro copper particles and the sub-micro copper particles are not impaired. Copper nanoparticles refer to copper particles having a particle size of less than 0.01 μm. From the viewpoint of making the sintered copper pillars more dense and improving the copper content, the content of the copper nanoparticles is preferably 30% by mass or less, more preferably 15% by mass or less, based on the total mass of the metal particles. More preferably, it is not contained.

(Other metal particles other than copper particles)
The metal particles may include other metal particles other than copper particles such as sub-micro copper particles and micro copper particles, and may include, for example, particles of nickel, silver, gold, palladium, platinum and the like. Other metal particles other than copper particles may have a volume average particle size of 0.01 μm or more and 10 μm or less, may be 0.01 μm or more and 5 μm or less, or may be 0.05 μm or more and 3 μm or less. . When other metal particles are contained, the content thereof may be less than 20% by mass or 10% by mass or less based on the total mass of the metal particles from the viewpoint of obtaining sufficient bonding properties. You may. Other metal particles may not be included. The shape of other metal particles is not particularly limited.

  When the copper paste contains metal particles other than copper particles, particularly when it contains metal particles having a metal type having a low melting point, the sintering temperature can be lowered. Furthermore, since a sintered body in which a plurality of kinds of metals are dissolved or dispersed can be obtained, mechanical properties such as yield stress and fatigue strength of the sintered body are improved, and connection reliability is easily improved. Further, by adding a plurality of types of metal particles, the sintered body can have sufficient bonding strength to a specific adherend. When the member of the joined body is a micro device, the die shear strength and connection reliability of the micro device are easily improved.

(Organic dispersion medium)
The organic dispersion medium may include a solvent having a boiling point of less than 300 ° C and / or a solvent having a boiling point of 300 ° C or more.

  Examples of the solvent having a boiling point of less than 300 ° C. include α-terpineol, diethylene glycol monobutyl ether, diethylene glycol monobutyl ether acetate, 4-methyl-1,3-dioxolan-2-one, diethylene glycol monobutyl ether, and the like. Solvents having a boiling point below 300 ° C. can be easily removed in a drying step or a heating step before sintering the pillar precursor.

  For the solvent having a boiling point of 300 ° C. or higher, it is preferable to select a structure having a high affinity for the metal particle surface in order to improve the dispersibility of the metal particles contained therein. When the metal particles have been surface-treated with a surface treatment agent containing an alkyl group, it is preferable to select a solvent having an alkyl group. Examples of such a solvent having a boiling point of 300 ° C. or higher include isobornylcyclohexanol (MTPH, manufactured by Nippon Terpene Co., Ltd.), butyl stearate, exepal BS (manufactured by Kao Corporation), stearyl stearate, exexel SS (manufactured by Kao Corporation) ), 2-ethylhexyl stearate, Exepearl EH-S (manufactured by Kao Corporation), isotridecyl stearate, exepearl TD-S (manufactured by Kao Corporation), isooctadecanol, fine oxocol 180 (manufactured by Nissan Chemical Industries, Ltd.), fine oxo Cole 180T (manufactured by Nissan Chemical Co., Ltd.), 2-hexyldecanol, Fineoxocol 1600 (manufactured by Nissan Chemical Co., Ltd.), tributyrin, tetraethylene glycol, heptadecane, octadecane, nonadecane, eicosan, heneicosan, docosan, methylheptadecane, tride Silcyclohexane, tetradecylcyclohexane, pentadecylcyclohexane, hexadecylcyclohexane, undecylbenzene, dodecylbenzene, tetradecylbenzene, tridecylbenzene, pentadecylbenzene, hexadecylbenzene, heptadecylbenzene, nonylnaphthalene, diphenylpropane, octanoic acid Octyl, methyl myristate, ethyl myristate, methyl linoleate, methyl stearate, triethylene glycol bis (2-ethylhexanoate), tributyl citrate, pentyl phenol, dibutyl sebacate, oleyl alcohol, cetyl alcohol, methoxyphenethyl alcohol Benzylphenol, hexadecanitrile, heptadecanitrile, benzyl benzoate, cinmethylin and the like. That.

  As the solvent having a boiling point of 300 ° C or higher, a solvent having a boiling point of 310 ° C or higher is more preferable. The dispersion medium having such a boiling point remains in the pillar precursor up to a firing temperature of 150 ° C. to 300 ° C., and can maintain adhesion and flexibility. On the other hand, as the solvent having a boiling point of 300 ° C or higher, a solvent having a boiling point of 450 ° C or lower is preferable, and a solvent having a boiling point of 400 ° C or lower is more preferable. Even if the solvent is at a temperature below the boiling point, the solvent is volatilized and removed by its vapor pressure, but in the case of a solvent having a boiling point of more than 450 ° C, the volatilization rate is too slow even at a sintering temperature of 150 ° C to 300 ° C, and the solvent remains. It is not preferable because sintering is easily inhibited by the solvent.

  The content of the organic dispersion medium may be 5 to 50 parts by mass based on 100 parts by mass of the total mass of the metal particles. When the content of the organic dispersion medium is within the above range, the viscosity of the copper paste can be adjusted to be more appropriate, and sintering of the copper particles is not easily inhibited.

  The type of the organic dispersion medium contained in the copper paste can be analyzed by, for example, gas chromatography-mass spectrometry of hot desorbed gas and TOF-SIMS. As another analysis method, the supernatant obtained by separating the particle components by centrifugation may be identified by ordinary organic analysis, for example, FT-IR, NMR, liquid chromatography, or a combination thereof. The ratio of the type of the organic dispersion medium can be determined by liquid chromatography, NMR, or the like.

(Flexibility imparting component)
The copper paste of the present embodiment can include a flexibility-imparting component. Examples of the flexibility-imparting component include a thermally decomposable resin.

  The thermally decomposable resin is preferably an amorphous polymer that can exhibit adhesiveness or tackiness for the purpose of temporarily fixing the adherend and the pillar precursor from the formation of the pillar precursor to baking. Further, the thermally decomposable resin preferably has a thermal decomposability that can be decomposed at a sintering temperature and decomposed without residue.

  The heat decomposable temperature of the heat decomposable resin is preferably 300 ° C. or lower, more preferably 250 ° C. or lower. The thermal decomposition temperature of the thermally decomposable resin is the temperature at which the thermally decomposable resin begins to decompose, and is defined as a 5% weight loss temperature in TG / DTA measurement. However, this temperature means a decomposition starting temperature not in an oxidizing atmosphere such as air but in a reducing atmosphere containing hydrogen or formic acid or in an inert gas atmosphere from which oxygen has been removed.

  The residue of the pyrolyzable resin after pyrolysis is preferably as small as possible to prevent sintering of the copper particles. The amount of the residue at the sintering temperature is usually preferably 5% by mass or less based on the mass of the resin before pyrolysis. % By mass or less is more preferable. The amount of the residue after the thermal decomposition of the thermally decomposable resin is the weight after holding the TG / DTA of the thermally decomposable resin in the inert gas (nitrogen or argon) containing 3 to 5% by mass at the sintering temperature for the sintering time. It can be measured as a change. Note that TG / DTA measurement in air is not preferable because oxidative decomposition proceeds and the amount of residue is smaller than that in a reducing atmosphere.

  Note that the thermally decomposable resin needs to have solubility in the organic dispersion medium described above. Examples of the thermally decomposable resin having solubility in an organic dispersion medium and the above-mentioned desired properties include polycarbonate, polymethacrylic acid, polymethacrylate, and polyester.

  The amount of the thermally decomposable resin in the copper paste may be 25% by mass or less, 15% by mass or less, 5% by mass or less, or 3% by mass or less. Good. If the purpose is to form a sintered copper pillar, it is not necessary to mix a thermally decomposable resin. On the other hand, the amount of the thermally decomposable resin in the paste may be 5% by mass or more from the viewpoint of increasing the ratio of the flexibility-imparting component contained in all the solvents and reducing the progress of drying.

  The viscosity of the copper paste for forming a sintered copper pillar of the present embodiment can be adjusted to a viscosity suitable for a printing / coating method for forming a pillar precursor. The viscosity of the copper paste at 25 ° C. may be from 50 Pa · s to 2000 Pa · s, from 100 Pa · s to 1750 Pa · s, or from 200 Pa · s to 1500 Pa · s. . When the viscosity of the copper paste is in the above range, it becomes easy to form a pillar precursor by various printing methods described below.

  In this specification, the viscosity of the copper paste for forming a sintered copper pillar means a value measured by an E-type viscometer at 25 ° C. and a rotation speed of 0.5 rpm. As the E-type viscometer, for example, a VISCOMMETER-TV33 type viscometer manufactured by Toki Sangyo Co., Ltd. can be used. As the jig for measuring the cone rotor, for example, 3 ° × R14, SPP can be applied.

  The copper paste for forming a sintered copper pillar of the present embodiment may have a thixotropy index (hereinafter, also referred to as TI value) of 2.0 or more and 20 or less, or 3.0 or more and 15 or less, It may be 4.0 or more and 10 or less. When the TI value of the copper paste is within this range, the viscosity of the copper paste becomes low due to the shearing force. Therefore, before printing, a manual operation or a stirring device (for example, a rotation and revolution type stirring device (Planetary Vacuum Mixer ARV-310, stock) (Shinky Co., Ltd.) etc.) makes it easy to print, and after the copper paste adheres to the member to be adhered, the viscosity is restored by standing and the excessive spread of printed matter can be suppressed. it can.

In the present specification, the TI value is μ _0.5 , measured at 25 ° C. under a condition of a rotation speed of 0.5 rpm using an E-type viscometer, and measured at 25 ° C. under a condition of a rotation speed of 5 rpm. viscosity as is at a ₅ mu, and the value calculated by the following equation.
TI value = μ _0.5 / μ ₅

(Method of preparing copper paste)
The copper paste can be prepared by mixing the above-described copper particles, the organic dispersion medium, and if necessary, the flexibility-imparting component, other metal particles, and any additives. For example, it can be prepared by dissolving a flexibility-imparting component in an organic solvent, adding sub-micro copper particles, micro copper particles, other metal particles, and an optional additive, and performing a dispersion treatment. Alternatively, it is prepared by adding a solution in which a flexibility-imparting component is mixed and dissolved in an organic solvent, a dispersion obtained by mixing and dispersing copper particles in a solvent, and adding other metal particles and optional additives. Can be.

  When the copper particles include sub-micro copper particles and micro copper particles, a dispersing agent is added to an organic solvent or a component for imparting flexibility, if necessary, the sub-micro copper particles are first mixed, and then a dispersion treatment is performed. Dispersion treatment may be performed by adding copper particles and, if necessary, other metal particles. The dispersion method and dispersion conditions suitable for dispersion may differ between the sub-micro copper particles and the micro copper particles. Generally, sub-micro copper particles require a stronger dispersion than micro copper particles.On the other hand, micro copper particles are easy to disperse, and not only a dispersion with low strength is sufficient, but also a strong dispersion causes deformation of the micro copper particles. Occurs. By performing the above procedure, the dispersibility is improved, and the performance of the copper paste can be further improved. Aggregates may be removed by performing a classification operation on the dispersion.

  In the present preparation method, a stirring treatment may be performed after the respective components are mixed. For the copper paste, the maximum particle size of the dispersion may be adjusted by a classification operation. At this time, the maximum particle size of the dispersion may be 20 μm or less, and may be 10 μm or less.

  The dispersion treatment can be performed using a disperser or a stirrer. For example, Ishikawa type stirrer, Silverson stirrer, cavitation stirrer, rotation revolving type stirrer, ultra-thin high-speed rotary type disperser, ultrasonic disperser, Raikai machine, twin-screw kneader, bead mill, ball mill, three-roll mill, homomixer , A planetary mixer, an ultra-high pressure type disperser, and a thin layer shear disperser.

  The stirring process can be performed using a stirrer. For example, an Ishikawa-type stirrer, a rotation revolving-type stirrer, a Raikai machine, a twin-screw kneader, a three-roll mill, and a planetary mixer are exemplified.

  The classification operation can be performed using, for example, filtration, spontaneous sedimentation, and centrifugation. Examples of the filter for filtration include a water comb, a metal mesh, a metal filter, and a nylon mesh.

(Formation of pillar precursor)
In the method of the present embodiment, a copper paste (copper paste for forming a sintered copper pillar) is formed into a pillar shape by printing on a first member, and then the first member is mounted. A pillar precursor can be provided between the member and the second member.

  As a printing method of the copper paste, for example, screen printing, transfer printing, offset printing, jet printing, dispenser, jet dispenser, needle dispenser, comma coater, slit coater, die coater, gravure coater, slit coat, letterpress printing, intaglio printing, Gravure printing, stencil printing, soft lithography, bar coating, applicator, particle deposition method, spray coater, spin coater, dip coater, electrodeposition coating and the like can be used.

  It is preferable to form the copper paste into a pillar shape by screen printing or stencil printing from the viewpoint that the manufacturing process is simple, shape stability is easily maintained, and thick film printing is easily performed. In this case, for example, the metal mask 4 is arranged on the first member 1 (FIG. 2A), and then the copper paste 3a is extended by using a squeegee 5, and the copper paste is 3a is filled (FIGS. 2B and 2C). Thus, the copper paste 3b formed in a pillar shape is provided on the first member 1 (FIG. 3A).

  The metal mask used for screen printing or stencil printing may have a via diameter of 30 μm to 200 μm, or 50 μm to 100 μm. The arrangement of the holes may be a lattice shape, and the pitch interval may be 1 μm or more and 500 μm or less. The squeegee angle may be 10 ° or more and 90 ° or less, or may be 45 ° or more and 70 ° or less.

  The printing height H1 may be 5 μm or more and 500 μm or less, or may be 10 μm or more and 200 μm or less. Further, the wetting spread W1 from the end of the pillar after printing may be 100 μm or less, or may be 50 μm or less.

  The indentation depth (H1-H2) when the second member 2 is mounted may be 500 μm or less, 100 μm or less, or 50 μm or less from the top of the pillar-shaped copper paste. H2 is set in consideration of the height of the formed sintered copper pillar or pillar precursor.

  For example, when the first member and the second member are a microdevice and a substrate, the mounting of the second member is performed using, for example, a chip mounter, a flip chip bonder, or a positioning jig made of carbon or ceramics. Can be.

  Thus, the pillar precursor 3c is provided between the first member 1 and the second member 2 (FIG. 3B).

  Next, a sintered copper pillar 3 is formed by sintering the pillar precursor 3c disposed between the first member 1 and the second member 2, thereby obtaining a joined body 10 (( c)).

  The pillar precursor may be appropriately dried from the viewpoint of suppressing the flow and the generation of voids during sintering. The gas atmosphere during drying may be the air, an oxygen-free atmosphere such as nitrogen or a rare gas, or a reducing atmosphere such as hydrogen or formic acid. The drying method may be drying at room temperature, drying by heating, or drying under reduced pressure. For heating drying or reduced pressure drying, for example, a hot plate, a hot air dryer, a hot air heating furnace, a nitrogen dryer, an infrared dryer, an infrared heating furnace, a far infrared heating furnace, a microwave heating device, a laser heating device, an electromagnetic A heating device, a heater heating device, a steam heating furnace, a hot plate pressing device, or the like can be used. The drying temperature and time may be appropriately adjusted according to the type and amount of the organic dispersion medium and the flexibility-imparting component used. The drying temperature and time may be, for example, from 50 ° C. to 180 ° C. for 30 seconds to 120 minutes.

  The sintering of the pillar precursor can be performed by heat treatment. The heating treatment includes, for example, a hot plate, a hot air dryer, a hot air heating furnace, a nitrogen dryer, an infrared dryer, an infrared heating furnace, a far infrared heating furnace, a microwave heating device, a laser heating device, an electromagnetic heating device, A heater heating device, a steam heating furnace, or the like can be used.

  The gas atmosphere during sintering may be a reducing atmosphere from the viewpoint of removing copper particles contained in the pillar precursor and surface oxides on the adhered surface. Examples of the reducing atmosphere include pure hydrogen gas, a mixed gas of hydrogen and nitrogen represented by a forming gas, nitrogen in formic acid gas, mixed gas of hydrogen and rare gas, and rare gas containing formic acid gas. No.

  In the present embodiment, when the diameter of the pillar precursor is small (especially when the diameter is 200 μm or less), formic acid enters the pillar precursor, so that the copper particles are easily reduced, and the copper particles are reduced in a reducing atmosphere containing formic acid gas. Can be sufficiently sintered. In this case, sintering can be performed using a formic acid reflow furnace, and the degree of sintering can be efficiently improved.

  The maximum temperature reached during the heat treatment may be 150 ° C. or more and 300 ° C. or less from the viewpoint of sufficiently promoting sintering, reducing thermal damage to members such as microdevices and substrates, and improving the yield. The temperature may be not lower than 250 ° C and not lower than 200 ° C. If the ultimate temperature is 150 ° C. or higher, sintering tends to proceed sufficiently even when the ultimate temperature holding time is 60 minutes or less.

  The maximum temperature holding time at which the organic dispersion medium and the flexibility-imparting component can be sufficiently removed, the sintering can be sufficiently advanced, and from the viewpoint of improving the yield, even if it is 1 minute or more and 60 minutes or less. The time may be 1 minute or more and less than 40 minutes, or 1 minute or more and less than 30 minutes.

  The method for manufacturing a joined body of the present embodiment may further include a step of filling a resin around the sintered copper pillar. In this case, a joined body 20 in which the sealing material 6 is provided between the first member 1 and the second member 2 is obtained.

  As the sealing material, from the viewpoint of protecting the joining portion from heat, moisture and impact and further improving the connection reliability, a sealing material for compression molding, a liquid sealing material, a sealing material for transfer molding, a sealing material for underfill. A stop may be used.

<Members with pillars for joining>
The member with a pillar for joining of the present embodiment is a member with a pillar for joining, which includes a member having a metal layer and a pillar provided on the metal layer, and is joined to another member via the pillar. The pillar is made of sintered copper, and the content of copper contained in the pillar is 96% by mass or more based on the total mass of the components constituting the pillar (excluding carbon, oxygen, and nitrogen). Is 50% by volume or more.

  FIG. 5 is a schematic sectional view showing one embodiment of a member with a pillar for joining. 5 includes a first member 1 and a pillar 3 d provided on the first member 1. The joining pillar-attached member 30 is joined to the second member.

  The member with a pillar for joining 30 is used, for example, in the same manner as in the method for manufacturing a joined body of the present embodiment described above, until the copper paste is formed into a pillar shape on the first member (FIG. 3A). ), And by sintering a copper paste formed into a pillar shape.

  The selection of the members, the preparation of the copper paste, and the molding and sintering of the copper paste can be performed in the same manner as in the above-described method for manufacturing a joined body of the present embodiment. The same applies to preferable conditions.

  The joining pillar made of sintered copper and having the above configuration can be formed in a shorter time than electrolytic plating, is excellent in shortened thermal conductivity and electric conductivity, and is less likely to cause electromigration. According to the joining pillar-equipped member including such pillars, it is easy to secure the connection reliability of the joined body obtained by joining to another member, and the manufacturing process of the joined body can be shortened. Can be planned.

  When joining the member with a pillar for joining of this embodiment to another member via a pillar, a copper paste can be used. In this case, the pillars are joined with the same kind of sintered copper, so that the effects of improving electromigration resistance, suppressing Kirkendall voids, improving thermal conductivity, and improving data transmission characteristics can be obtained. A package having excellent characteristics can be obtained. The above-mentioned copper paste can have the same configuration as the copper paste for forming a sintered copper pillar of the present embodiment.

  Hereinafter, the present invention will be described more specifically with reference to Examples and Comparative Examples, but the present invention is not limited to the following Examples.

(Example 1)
Preparation of copper paste, production and evaluation of a joined body, and production and evaluation of a member with a pillar for joining were performed by the following methods.

[Preparation of copper paste]
0.42 g (8.4% by mass) of α-terpineol (manufactured by Wako Pure Chemical Industries, Ltd.) and 0.18 g (3.6% by mass) of tributyrin as a dispersion medium, and CH-0200 (Mitsui Metals) as sub-micro copper particles 3.47 g (69.52 mass%) (trade name, 50% volume average particle size: 0.36 μm), and MA-C025 (trade name, volume average particle size, manufactured by Mitsui Mining & Smelting Co., Ltd.) as micro copper particles 7.5 μm) 0.83 g (16.544 mass%), zinc (Alfa Aesar, product number: 13789) 0.01 g (0.176 mass%), and lauric acid (Mitsui Metal Mining Co., Ltd.) as a surface treatment agent 0.1 g (1.76 mass%) was kneaded in an agate mortar until dry powder disappeared, and the mixture was transferred to a plastic bottle. The amount in parentheses indicates the amount of the copper paste based on the total amount.

The sealed plastic bottle was stirred for 2 minutes at 2000 min ⁻¹ (2000 rotations / minute) using a rotation and revolution type stirring device (Planetary Vacuum Mixer ARV-310, manufactured by Sinky Co., Ltd.). Thus, a copper paste 1 was obtained.

[Preparation of bonded body]
Using the copper paste 1, a joined body was formed by the following method. A stainless steel metal mask (784 openings per 7 mm square, with a thickness of 130 mm) arranged in a grid pattern on a copper plate (15 mm square, thickness 0.3 mm) as a first member with a pitch of 250 μm in the thickness: 50 μm), and a copper paste was applied by stencil printing using a metal squeegee. A Ni-plated Si chip (3 mm square, 0.15 mm thick) as a second member is placed on the pillar-shaped copper paste provided on the substrate, and the upper part of the Si chip is pressed using a pressing jig with a spencer. 10 μm. Thereafter, the laminate (copper plate / pillar precursor / Si chip) is put into a hydrogen sintering furnace (hydrogen 100% reducing atmosphere), heated to 225 ° C. at a rate of 7.5 ° C./min, and heated at 225 ° C. to 60 ° C. Hold for minutes. Thereafter, the assembly was cooled to 200 ° C. over 5 minutes, kept at 200 ° C. for 5 minutes, and rapidly cooled to room temperature to obtain a joined body 1.

[Evaluation of bonding condition]
The joined body obtained above was put into a cup, fixed with a sample clip (Samplklip I, manufactured by Buehler), and an epoxy casting resin (trade name “Epomount”, manufactured by Refinetech) was attached to the periphery of the joined body. The mixture was poured until the whole was filled, left in a vacuum desiccator, and degassed by reducing the pressure for 1 minute.

  Thereafter, the epoxy cast resin was cured by being left at room temperature (25 ° C.) for 10 hours to obtain a cast sample. The cast sample was cut using a Refineso Excel (manufactured by Refinetech) equipped with a resinoid cutting wheel near the cross section of the cast sample to be observed. Then, a cross section was cut with a polishing apparatus (Refine Polisher HV, manufactured by Refinetech) equipped with water-resistant abrasive paper (Carbomac Paper, manufactured by Refinetech), and a joint portion of the sintered copper pillar was obtained. Further, an end portion of the mask coming out of the mask was cut off in the CP mode using an ion milling apparatus “IM4000” (manufactured by Hitachi, Ltd.) to prepare an observation sample.

The cross section of the bonding portion in the observation sample was observed at an applied voltage of 10 kV and various magnifications, and the bonding state was evaluated based on the following criteria.
[Criteria]
A: The sintered copper pillar is joined to the copper substrate and the Si chip.
B: Cracks or peeling are seen in a part of the joint, but they are joined.
C: The sintered copper pillar was not bonded to the copper substrate and the Si chip.

[Production of a member with a pillar for joining]
Using the copper paste 1, a member with a pillar for joining was produced by the following method, and this was used as a sample for shear strength measurement. A stainless metal mask (784 apertures per 7 mm square) in which a Ni-plated Si chip (10 mm square, thickness 0.15 mm) as a member is formed in a lattice pattern with openings of 130 μm in a grid pattern at a pitch interval of 250 μm. , Thickness: 50 μm), and a copper paste was applied by stencil printing using a metal squeegee. The Si chip provided with the pillar-shaped copper paste was placed in a hydrogen sintering furnace (100% hydrogen reducing atmosphere), heated to 225 ° C. at a rate of 7.5 ° C./min, and held at 225 ° C. for 60 minutes. Thereafter, the mixture was cooled to 200 ° C. over 5 minutes, kept at 200 ° C. for 5 minutes, and then rapidly cooled to room temperature to obtain a member 1 with a pillar for bonding provided with a sintered copper pillar on a Si chip.

[Measurement of bonding strength]
With respect to the joining strength between the sintered copper pillar and the Si chip in the joining pillar-attached member 1, the shear strength was measured by the following method. The sintered copper pillar of the member 1 with a pillar for joining is subjected to a tool height of 10 μm and a measuring speed by a bonding strength tester “Universal Bond Tester System 650” (manufactured by Hugle Electronics) equipped with an SMS-5K-21859 load cell. The wafer was pushed horizontally at 10 μm / s, and the shear strength with the Si chip as the adherend was measured. The average of six or more measured values was defined as the shear strength.

[Variation in pillar height]
The shape of the sintered copper pillar in the member 1 with a pillar for joining was read in a grid by using a laser displacement meter “LEXT OSL4100” (manufactured by OLYMPUS). Thereafter, the distance between the bottom of the sintered copper pillar and the vertex of the pillar (the highest point at the center) was calculated as the pillar height. The standard deviation (σ) was determined from the height values at 10 points, and this was evaluated as a height variation.

(Example 2)
In the production of the joined body, a Cu chip (3 mm square, 0.15 mm in thickness) was used instead of the Ni-plated Si chip, and in the production of the joining pillar-attached member, the Ni-plated Si chip was substituted. In the same manner as in Example 1 except that a Cu plate (15 mm square, thickness 0.3 mm) was used, preparation of a copper paste, production and evaluation of a joined body, and production of a member with a pillar for joining and The evaluation was performed.

(Example 3)
Production and evaluation of a joined body, and production and evaluation of a member with a pillar for joining were performed in the same manner as in Example 1 except that the copper paste 3 shown below was used instead of the copper paste 1.

0.455 g (9.1% by mass) of α-terpineol (manufactured by Wako Pure Chemical Industries, Ltd.) and 0.195 g (3.9% by mass) of tributyrin as a dispersion medium and CH-0200 (Mitsui Metals) as sub-micro copper particles Co., Ltd., 50% volume average particle diameter: 0.36 μm) 4.34 g (86.826 mass%) and zinc (Alfa Aesar, product number: 13789) 0.01 g (0.174 mass%) The mixture was kneaded in an agate mortar until dry powder disappeared, and the mixture was transferred to a plastic bottle. The sealed plastic bottle was stirred for 2 minutes at 2000 min ⁻¹ (2000 rotations / minute) using a rotation and revolution type stirring device (Planetary Vacuum Mixer ARV-310, manufactured by Sinky Co., Ltd.). Thus, a copper paste 3 was obtained.

(Example 4)
In the manufacture of the joined body and the member with a pillar for joining, copper was used in the same manner as in Example 3 except that a Cu chip (3 mm square, 0.15 mm thick) was used instead of the Ni-plated Si chip. Preparation of paste, production of a joined body and its evaluation, and production of a member with a pillar for joining and its evaluation were performed.

(Example 5)
Production and evaluation of a joined body and production and evaluation of a member with a pillar for joining were performed in the same manner as in Example 1 except that the copper paste 5 shown below was used instead of the copper paste 1.

0.42 g (8.4% by mass) of α-terpineol (manufactured by Wako Pure Chemical Industries, Ltd.) and 0.18 g (3.6% by mass) of tributyrin as a dispersion medium, and CH-0200 (Mitsui Metals) as sub-micro copper particles 3.47 g (70.4% by mass), 50% volume average particle size: 0.36 μm, and 3L3N as micro copper particles (50% volume average particle size: 5,5%). 7 μm) 0.83 g (17.424% by mass) and 0.01 g (0.176% by mass) of zinc (manufactured by Alfa Aesar, product number: 13789) are kneaded in an agate mortar until there is no dry powder, and mixed. The solution was transferred to a plastic bottle. The sealed plastic bottle was stirred for 2 minutes at 2000 min ⁻¹ (2000 rotations / minute) using a rotation and revolution type stirring device (Planetary Vacuum Mixer ARV-310, manufactured by Sinky Co., Ltd.). Thus, a copper paste 5 was obtained.

(Example 6)
In the manufacture of the joined body and the member with a pillar for joining, copper was used in the same manner as in Example 5 except that a Cu chip (3 mm square, 0.15 mm thick) was used instead of the Ni-plated Si chip. Preparation of paste, production of a joined body and its evaluation, and production of a member with a pillar for joining and its evaluation were performed.

(Example 7)
Production and evaluation of a joined body, and production and evaluation of a member with a pillar for joining were performed in the same manner as in Example 1 except that the copper paste 7 shown below was used instead of the copper paste 1.

0.455 g (9.1% by mass) of α-terpineol (manufactured by Wako Pure Chemical Industries, Ltd.) and 0.195 g (3.9% by mass) of tributyrin as a dispersion medium and CH-0200 (Mitsui Metals) as sub-micro copper particles 3.91 g (78.3 mass%) of 50% volume average particle size: 0.36 μm, manufactured by Sharp Corporation, and 3L3N (manufactured by Fukuda Metal Foil & Powder Co., Ltd .; 0.4263 g (8.526 mass%) and 0.01 g (0.174 mass%) of zinc (manufactured by Alfa Aesar, product number: 13789) are kneaded in an agate mortar until there is no dry powder, and mixed. The solution was transferred to a plastic bottle. The sealed plastic bottle was stirred for 2 minutes at 2000 min ⁻¹ (2000 rotations / minute) using a rotation and revolution type stirring device (Planetary Vacuum Mixer ARV-310, manufactured by Sinky Co., Ltd.). Thus, a copper paste 7 was obtained.

(Example 8)
Production and evaluation of a joined body, and production and evaluation of a member with a pillar for joining were performed in the same manner as in Example 1 except that a copper paste 8 shown below was used instead of the copper paste 1.

0.420 g (8.4% by mass) of α-terpineol (manufactured by Wako Pure Chemical Industries, Ltd.) and 0.180 g (3.6% by mass) of tributyrin as a dispersion medium and CH-0200 (Mitsui Metals) as sub-micro copper particles Co., Ltd., 50% volume average particle size: 0.36 μm, manufactured by Mitsui Kinzoku Co., Ltd.) 3.080 g (61.6 mass%) and 3L3N as micro copper particles (Fukuda Metal Foil & Powder Co., Ltd., 50% volume average) 1.3112 g (26.224 mass%) of zinc (Alfa Aesar, product number: 13789) 0.01 g (0.176 mass%) of 1.3112 g (26.224 mass%) of dried powder disappears in an agate mortar. And the mixture was transferred to a plastic bottle. The sealed plastic bottle was stirred for 2 minutes at 2000 min ⁻¹ (2000 rotations / minute) using a rotation and revolution type stirring device (Planetary Vacuum Mixer ARV-310, manufactured by Sinky Co., Ltd.). Thus, a copper paste 8 was obtained.

(Example 9)
In the production of the joined body and the member with a pillar for joining, copper was used in the same manner as in Example 8 except that a Cu chip (3 mm square, 0.15 mm thick) was used instead of the Ni-plated Si chip. Preparation of paste, production of a joined body and its evaluation, and production of a member with a pillar for joining and its evaluation were performed.

(Example 10)
Production and evaluation of a joined body, and production and evaluation of a member with a pillar for joining were performed in the same manner as in Example 1 except that the copper paste 10 shown below was used instead of the copper paste 1.

0.42 g (8.4% by mass) of α-terpineol (manufactured by Wako Pure Chemical Industries, Ltd.) and 0.18 g (3.6% by mass) of tributyrin as a dispersion medium, and CH-0200 (Mitsui Metals) as sub-micro copper particles 2.86 g (57.2% by mass), 50% volume average particle size: 0.36 μm, manufactured by Sharp Corporation, and 3L3N (50% volume average particle size, manufactured by Fukuda Metal Foil & Powder Co., Ltd.) as micro copper particles. 7 μm) 1.53 g (30.624% by mass) and 0.01 g (0.176% by mass) of zinc (manufactured by Alfa Aesar, product number: 13789) are kneaded in an agate mortar until there is no dry powder, and mixed. The solution was transferred to a plastic bottle. The sealed plastic bottle was stirred for 2 minutes at 2000 min ⁻¹ (2000 rotations / minute) using a rotation and revolution type stirring device (Planetary Vacuum Mixer ARV-310, manufactured by Sinky Co., Ltd.). Thus, a copper paste 10 was obtained.

(Example 11)
Production and evaluation of a joined body, and production and evaluation of a member with a pillar for joining were performed in the same manner as in Example 1 except that the copper paste 11 shown below was used instead of the copper paste 1.

0.42 g (8.4% by mass) of α-terpineol (manufactured by Wako Pure Chemical Industries, Ltd.) and 0.18 g (3.6% by mass) of tributyrin as a dispersion medium, and CH-0200 (Mitsui Metals) as sub-micro copper particles 2.64 g (52.8% by mass), 50% volume average particle size: 0.36 μm, manufactured by Fukuda Metal Foil & Powder Co., Ltd .; (7 μm) 1.7512 g (35.024% by mass) and 0.01 g (0.176% by mass) of zinc (manufactured by Alfa Aesar, product number: 13789) are kneaded in an agate mortar until there is no dry powder, and mixed. The solution was transferred to a plastic bottle. The sealed plastic bottle was stirred for 2 minutes at 2000 min ⁻¹ (2000 rotations / minute) using a rotation and revolution type stirring device (Planetary Vacuum Mixer ARV-310, manufactured by Sinky Co., Ltd.). Thus, a copper paste 11 was obtained.

(Example 12)
Production and evaluation of a joined body and production and evaluation of a member with a pillar for joining were performed in the same manner as in Example 1, except that the copper paste 12 shown below was used instead of the copper paste 1.

0.42 g (8.4% by mass) of α-terpineol (manufactured by Wako Pure Chemical Industries, Ltd.) and 0.18 g (3.6% by mass) of tributyrin as a dispersion medium, and CH-0200 (Mitsui Metals) as sub-micro copper particles 1.32 g (26.4% by mass) of 50% volume average particle size: 0.36 μm, manufactured by Sharp Corporation, and 3L3N (manufactured by Fukuda Metal Foil & Powder Co., Ltd., 50% volume average particle size: 5.0) as micro copper particles. 3.0712 g (61.424 mass%) and 0.01 g (0.176 mass%) of zinc (manufactured by Alfa Aesar, product number: 13789) are kneaded in an agate mortar until the dry powder disappears, and mixed. The solution was transferred to a plastic bottle. The sealed plastic bottle was stirred for 2 minutes at 2000 min ⁻¹ (2000 rotations / minute) using a rotation and revolution type stirring device (Planetary Vacuum Mixer ARV-310, manufactured by Sinky Co., Ltd.). Thus, a copper paste 12 was obtained.

(Example 13)
Production and evaluation of a joined body, and production and evaluation of a member with a pillar for joining were performed in the same manner as in Example 1 except that the copper paste 13 shown below was used instead of the copper paste 1.

0.425 g (8.5% by mass) of α-terpineol (manufactured by Wako Pure Chemical Industries, Ltd.) and 0.425 g (8.5% by mass) of tributyrin as dispersion media, and CH-0200 (Mitsui Metals) as sub-micro copper particles 2.90 g (58.1 mass%) of 50% volume average particle size: 0.36 μm, manufactured by Sharp Corporation, and 3L3N as micro copper particles (manufactured by Fukuda Metal Foil & Powder Co., Ltd., 50% volume average particle size: 5.50%). 7 μm) 0.83 g (24.734% by mass) and 0.01 g (0.166% by mass) of zinc (manufactured by Alfa Aesar, product number: 13789) are kneaded in an agate mortar until no dry powder is present and mixed. The solution was transferred to a plastic bottle. The sealed plastic bottle was stirred for 2 minutes at 2000 min ⁻¹ (2000 rotations / minute) using a rotation and revolution type stirring device (Planetary Vacuum Mixer ARV-310, manufactured by Sinky Co., Ltd.). Thus, a copper paste 13 was obtained.

(Example 14)
Production and evaluation of a joined body, and production and evaluation of a member with a pillar for joining were performed in the same manner as in Example 1 except that the copper paste 14 shown below was used instead of the copper paste 1.

0.75 g (15.0% by mass) of α-terpineol (manufactured by Wako Pure Chemical Industries, Ltd.) and 0.75 g (15.0% by mass) of tributyrin as dispersion media, and CH-0200 (Mitsui Metals) as sub-micro copper particles Co., Ltd., 50% volume average particle size: 0.36 μm) 2.45 g (49.0 mass%), and 3L3N as micro copper particles (Fukuda Metal Foil & Powder Co., Ltd., 50% volume average particle size: 5.50 g). 7 μm) 1.043 g (20.86% by mass) and 0.01 g (0.14% by mass) of zinc (manufactured by Alfa Aesar, product number: 13789) were kneaded in an agate mortar until the dry powder disappeared, and mixed. The solution was transferred to a plastic bottle. The sealed plastic bottle was stirred for 2 minutes at 2000 min ⁻¹ (2000 rotations / minute) using a rotation and revolution type stirring device (Planetary Vacuum Mixer ARV-310, manufactured by Sinky Co., Ltd.). Thus, a copper paste 14 was obtained.

(Example 15)
Production and evaluation of a joined body, and production and evaluation of a member with a pillar for joining were performed in the same manner as in Example 2 except that the copper paste 15 shown below was used instead of the copper paste 2.

1.250 g (25.0% by mass) of α-terpineol (manufactured by Wako Pure Chemical Industries, Ltd.) and 1.250 g (25.0% by mass) of tributyrin as dispersion media, and CH-0200 (Mitsui Metals) as sub-micro copper particles 1.75 g (35.0% by mass), 50% volume average particle size: 0.36 μm, and 3L3N (50% volume average particle size, manufactured by Fukuda Metal Foil & Powder Co., Ltd.) as micro copper particles. 7 μm) 1.043 g (14.9% by mass) and 0.01 g (0.1% by mass) of zinc (manufactured by Alfa Aesar, product number: 13789) were kneaded in an agate mortar until there was no dry powder, and mixed. The solution was transferred to a plastic bottle. The sealed plastic bottle was stirred for 2 minutes at 2000 min ⁻¹ (2000 rotations / minute) using a rotation and revolution type stirring device (Planetary Vacuum Mixer ARV-310, manufactured by Sinky Co., Ltd.). Thus, a copper paste 15 was obtained.

(Example 16)
Production and evaluation of a joined body, and production and evaluation of a member with a pillar for joining were performed in the same manner as in Example 2 except that a copper paste 16 shown below was used instead of the copper paste 2.

1.250 g (25.0% by mass) of α-terpineol (manufactured by Wako Pure Chemical Industries, Ltd.) and 1.250 g (25.0% by mass) of tributyrin as dispersion media, and CH-0200 (Mitsui Metals) as sub-micro copper particles 2.49 g (49.9% by mass, 50% volume average particle size: 0.36 μm) and 0.01 g (0.1% by mass) of zinc (manufactured by Alfa Aesar, product number: 13789). The mixture was kneaded in an agate mortar until dry powder disappeared, and the mixture was transferred to a plastic bottle. The sealed plastic bottle was stirred for 2 minutes at 2000 min ⁻¹ (2000 rotations / minute) using a rotation and revolution type stirring device (Planetary Vacuum Mixer ARV-310, manufactured by Sinky Co., Ltd.). Thus, a copper paste 16 was obtained.

(Example 17)
In the production of the joined body, a Cu chip (3 mm square, 0.15 mm in thickness) was used instead of the Ni-plated Si chip, and in the production of the joining pillar-attached member, the Ni-plated Si chip was substituted. In the same manner as in Example 10 except that a Cu plate (15 mm square, thickness 0.3 mm) was used, preparation of a copper paste, production and evaluation of a joined body, and production of a member with a pillar for joining and The evaluation was performed.

(Example 18)
In the production of the joined body and the member with a pillar for joining, the copper paste was prepared in the same manner as in Example 17 except that the sintering atmosphere was changed from a 100% hydrogen reducing atmosphere to a formic acid reducing atmosphere (formic acid gas concentration: 3%). Preparation, production and evaluation of a joined body, and production and evaluation of a member with a pillar for joining were performed.

(Example 19)
In the production of the joined body, an Au-plated Si chip (3 mm □, thickness 0.40 mm) is used instead of the Cu chip, and in the production of the member with a pillar for joining, Au plating is applied instead of the Cu plate. In the same manner as in Example 18 except that a Si chip (10 mm square, thickness 0.40 mm) was used, preparation of a copper paste, production and evaluation of a joined body, and production of a member with a pillar for joining and The evaluation was performed.

(Example 20)
In the production of the joined body, an Ag-plated Si chip (3 mm square, 0.40 mm thick) was used in place of the Cu chip, and in the production of the member with a pillar for joining, Ag plating was performed instead of the Cu plate. In the same manner as in Example 18 except that a Si chip (10 mm square, thickness 0.40 mm) was used, preparation of a copper paste, production and evaluation of a joined body, and production of a member with a pillar for joining and The evaluation was performed.

(Example 21)
In the production of the joined body, a Ni chip plated with Ni (3 mm square, 0.15 mm in thickness) was used instead of the Cu chip, and in the production of the member with pillars for joining, Ni plating was applied instead of the Cu plate. In the same manner as in Example 18 except that a Si chip (10 mm square, thickness 0.15 mm) was used, preparation of a copper paste, production and evaluation of a joined body, and production of a member with a pillar for joining and The evaluation was performed.

  Further, the viscosity and thixotropy index (TI value) of the copper paste 3, the copper paste 10, and the copper paste 16 were evaluated by the following methods. Table 4 shows the results.

[Measurement of viscosity]
Using an E-type viscometer (manufactured by Toki Sangyo Co., Ltd., product name: VISCOMTER-TV33) and a cone plate type rotor SSP or 3 ° × R14 as a measuring jig, and rotating at 0.5 rpm or 5 rpm, copper The viscosity of the paste at 25 ° C. was measured.

[Thixotropic index (TI value)]
From viscosity mu ₅ viscosity _{mu 0.5,} and the rotational speed 5rpm speed 0.5rpm measured above, to calculate the TI value by the following equation.
TI value = μ _0.5 / μ ₅

(Comparative Example 1)
Copper pillars were formed on a Ni-plated Si chip (10 mm square, 0.15 mm thick) as a member by electrolytic copper plating. The formation speed of the pillar was 0.3 μm / min, and it took 2.5 hours or more to form a pillar having a height of 50 μm. Also, when the plating speed was increased to 0.5 μm / min, the variation in pillar height became large.

  On the other hand, in the example, it can be seen that a sintered copper pillar having good height variation can be formed in 100 minutes, and both productivity and reliability can be achieved.

  Further, as shown in Tables 1 to 4, in the examples, copper sintered pillars can be formed on a copper plate in a good bonding state. In view of the fact that copper is a metal often used as a wiring or an electrode, the method for manufacturing a joined body according to the present invention is advantageous in reducing electromigration as compared with a case where a joining process based on solder bump joining is used. It can be said that. Note that electromigration is a phenomenon in which metal atoms used as wirings and electrodes move through crystal grain boundaries and the like, and cause a short circuit in equipment. Joining with the same kind of metal hardly generates an electric field, which is effective in reducing electromigration.

DESCRIPTION OF SYMBOLS 1 ... 1st member, 2 ... 2nd member, 3 ... sintered copper pillar, 3a ... copper paste, 4 ... metal mask, 5 ... squeegee, 10, 20 ... joined body, 30 ... joining member with pillar.

Claims (15)

A method of manufacturing a joined body including a first member, a second member, and a sintered copper pillar that joins the first member and the second member,
Forming a sintered copper pillar by sintering a pillar precursor disposed between the first member and the second member,
The pillar precursor contains metal particles and an organic dispersion medium,
A method for manufacturing a joined body, wherein the metal particles include copper particles.   The method for producing a joined body according to claim 1, wherein the copper particles include sub-micro copper particles having a volume average particle diameter of 0.01 µm or more and less than 0.8 µm. The content of copper contained in the sintered copper pillar is 96% by mass or more based on the total mass of the components constituting the sintered copper pillar (excluding carbon, oxygen, and nitrogen),
3. The method for manufacturing a joined body according to claim 1, wherein a volume ratio of copper in the sintered copper pillar is 50% by volume or more. 4.   The sintered copper pillar has a shortest distance H between a joint surface with the first member and a joint surface with the second member of 5 to 200 μm, and a minimum diameter W in a cross section perpendicular to a direction in which the pillar extends. The method for manufacturing a joined body according to any one of claims 1 to 3, wherein the ratio (H / W) of the H and the W (H / W) is 10 to 500 m, and 0.01 to 4.0.   The first member and / or the second member may include, on a bonding surface with the sintered copper pillar, at least one metal selected from the group consisting of copper, nickel, silver, platinum, gold, and palladium. The method for producing a joined body according to any one of claims 1 to 4, comprising:   The joined body according to claim 5, wherein a shear strength between the first member and / or the second member having the metal on the joint surface and the sintered copper pillar is 4 MPa or more. Production method.   After forming a copper paste containing the metal particles and the organic dispersion medium into a pillar shape by screen printing or stencil printing on the first member, the first member is mounted on the first member. The method for manufacturing a joined body according to claim 1, wherein the pillar precursor is provided between the member and the second member. The pillar-shaped copper paste has a height of 10 to 200 μm, a maximum diameter of the wet spread on the first member side is 50 μm or less,
The method for manufacturing a joined body according to claim 7, wherein the indentation depth when the second member is mounted is 50 µm or less.   An electronic device comprising: the joined body including a micro device as the first member, a substrate having an electrode as the second member, and the sintered copper pillar for electrically joining the micro device and the electrode. The method for producing a joined body according to any one of claims 1 to 8, which is a device.   The method for manufacturing a joined body according to claim 9, further comprising: filling a resin around the sintered copper pillar. A copper paste for forming a sintered copper pillar for joining members,
The copper paste contains metal particles and an organic dispersion medium,
The metal particles, the sub-micro copper particles having a volume average particle diameter of 0.01 μm or more and less than 0.8 μm, based on the total mass of the metal particles, containing 30% by mass or more and 100% by mass or less,
A copper paste for forming a sintered copper pillar, wherein the content of the organic dispersion medium is 5% by mass or more and 70% by mass or less based on the total mass of the copper paste.   12. The metal particle according to claim 11, further comprising micro copper particles having a volume average particle diameter of 0.8 µm or more and 50 µm or less, in a ratio of more than 0% by mass and 50% by mass or less based on the total mass of the metal particles. A copper paste for forming a sintered copper pillar according to the above.   The copper paste for forming a sintered copper pillar according to claim 11, wherein the viscosity at 25 ° C. is 50 to 2000 Pa · s, and the thixotropy index measured according to JIS Z3284 is 2.0 to 20. A member having a metal layer, comprising a pillar provided on the metal layer, a member with a pillar for joining to be joined to another member via the pillar,
The pillar is made of sintered copper,
The content of copper contained in the pillar is 96% by mass or more based on the total mass of components constituting the pillar (excluding carbon, oxygen, and nitrogen),
A member with a pillar for joining, wherein a volume ratio of copper in the pillar is 50% by volume or more. The member with a pillar for joining according to claim 14, wherein the shear strength between the pillar and the metal layer is 4 MPa or more.

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