JP6018831B2 - Manufacturing method of bonded structure - Google Patents

Description

  The present invention relates to a bonding composition used for bonding a semiconductor module or the like to a member such as a substrate, a bonding structure using the bonding composition, and a method for manufacturing the bonding structure.

  In a non-insulated semiconductor device which is one of power semiconductor devices used for an inverter or the like, a member for fixing a semiconductor element is also one of electrodes of the semiconductor device. For example, in a semiconductor device in which a power transistor is mounted on a fixing member using a Sn—Pb soldering material, the fixing member (base material) serves as a collector electrode of the power transistor. A current of several amperes or more flows through the collector electrode when the semiconductor device is operating, and the transistor chip generates heat. In order to avoid destabilization of characteristics and a decrease in service life due to this heat generation, it is necessary to sufficiently ensure the heat dissipation and heat resistance of the soldered portion. In order to ensure sufficient heat dissipation and heat resistance of the soldered portion, it is necessary to use a material having excellent heat dissipation.

  Also in an insulated semiconductor device, in order to operate a semiconductor element safely and stably, it is necessary to efficiently dissipate heat generated during operation of the semiconductor device to the outside of the semiconductor device. In this case, it is also necessary to ensure the bonding reliability of the soldered portion.

  As a bonding material having high heat dissipation and high bonding reliability, the following Patent Document 1 discloses a conductive adhesive containing a particulate silver compound. However, since bonding using this conductive adhesive is bonding by a cured product obtained by curing a thermosetting resin as a binder resin, heat dissipation and bonding reliability are compared with bonding by metal bonding at the bonding interface. There is a problem that the property becomes low.

  On the other hand, when the particle size of the metal particles is reduced to a size of 100 nm or less and the number of constituent atoms decreases, the surface area ratio to the volume of the particles increases rapidly, and the melting point or sintering temperature is significantly higher than in the bulk state. It is known to decline. Using this low-temperature firing function, a metal particle having an average particle diameter of 100 nm or less whose surface is coated with an organic material is used as a bonding material, and the organic material is decomposed by heating and the metal particles are sintered together to perform bonding. Are known. In this joining method, since the metal particles after joining are changed to bulk metal, and joining by metal bonding is obtained at the joining interface, heat resistance, joining reliability, and heat dissipation become extremely high. A bonding material for performing such bonding is disclosed in Patent Document 2 below, for example.

  In Patent Document 2, particles having an average particle diameter of 1 nm or more and 50 μm or less, which are one or more metal particle precursors selected from metal oxide, metal carbonate, or carboxylate metal salt particles, and an organic substance A bonding material containing a reducing agent is disclosed. In the total mass part in the bonding material, the content of the metal particle precursor is more than 50 parts by mass and 99 parts by mass or less.

JP 2003-309352 A JP 2008-178911 A

  In the conventional bonding material as described in Patent Document 2, there may be a variation in the interval between the members bonded by the bonding material. That is, the thickness of the joint formed by the joining material may vary. Therefore, there is a problem that reliability of electronic parts such as a semiconductor device using a conventional bonding material is lowered.

  The object of the present invention is used to join the first and second members to be joined. After joining, the joining reliability of the first and second members to be joined is increased, and the first and second members are further joined. It is providing the composition for joining which can control the space | interval between the to-be-joined member of high precision, the joining structure using this joining composition, and the manufacturing method of a joining structure.

  According to a wide aspect of the present invention, there is provided a bonding composition used for bonding the first and second members to be bonded, a bonding material containing metal atom-containing particles, and a CV value of a particle diameter of 10 The composition for joining containing the electroconductive particle which is% or less is provided.

  In a specific aspect of the bonding composition according to the present invention, the bonding material includes silver particles having an average particle diameter of 1 nm to 100 nm or copper particles having an average particle diameter of 1 nm to 100 nm. It is a bonding material containing silver oxide particles having an average particle diameter of 1 nm or more and 50 μm or less, or copper oxide particles having an average particle diameter of 1 nm or more and 50 μm or less and a reducing agent.

  In another specific aspect of the bonding composition according to the present invention, the metal atom-containing particles are sintered by heating at less than 400 ° C.

  In still another specific aspect of the bonding composition according to the present invention, the conductive particles include base particles and a conductive layer disposed on the surface of the base particles.

  In another specific aspect of the bonding composition according to the present invention, the outer surface of the conductive layer is a metal containing silver or copper.

  In still another specific aspect of the bonding composition according to the present invention, the outer surface of the conductive layer does not melt at 400 ° C.

  In another specific aspect of the bonding composition according to the present invention, the base particles are resin particles.

  Moreover, according to the wide situation of this invention, it is equipped with the 1st joining object member, the 2nd joining object member, and the junction part which joins this 1st, 2nd joining object member, This joining Part is formed using a bonding composition containing a bonding material containing metal atom-containing particles and conductive particles having a CV value of 10% or less of the particle diameter, and the bonding part is the bonding The composition is heated by sintering the metal atom-containing particles, and the first and second members to be joined are joined by the sintered product obtained by sintering the metal atom-containing particles. There is provided a bonded structure in which the conductive particles are disposed between the first and second members to be bonded.

  In a specific aspect of the bonded structure according to the present invention, when the average thickness of the bonded portion is T, the average diameter of the conductive particles in the thickness direction of the bonded portion after bonding is 0.8 T or more. Preferably there is.

  Moreover, according to the wide situation of this invention, between the 1st, 2nd joining object members, the joining material containing a metal atom containing particle and the electroconductive particle whose CV value of a particle diameter is 10% or less are contained. A step of disposing a bonding composition to be formed, and heating the bonding composition to sinter the metal atom-containing particles to form a bonded portion, whereby the first and second members to be bonded And joining the first and second members to be joined with the sintered product obtained by sintering the metal atom-containing particles, and between the first and second members to be joined, A bonded structure is provided that disposes conductive particles.

  Since the bonding composition according to the present invention contains a bonding material containing metal atom-containing particles and conductive particles having a particle diameter CV value of 10% or less, the bonding composition according to the present invention is used. When the first and second members to be joined are joined, the joining reliability of the first and second members to be joined is increased, and the interval between the first and second members to be joined is highly accurate. Can be controlled.

FIG. 1 is a cross-sectional view schematically showing a bonded structure using a bonding composition according to an embodiment of the present invention. FIG. 2 is a cross-sectional view showing conductive particles contained in the bonding composition according to one embodiment of the present invention. FIG. 3 is a cross-sectional view showing a modified example of the conductive particles shown in FIG.

  Hereinafter, the present invention will be described in detail.

  The joining composition according to the present invention is used to join the first joining target member and the second joining target member. The joining composition according to the present invention contains a joining material containing metal atom-containing particles and conductive particles having a particle diameter CV value of 10% or less. When the first and second joining target members are joined by the joining material having such a composition, the joining portion having the portion formed by the joining material containing the metal atom-containing particles, the first and second joining target members, It is possible to improve the bonding reliability. Furthermore, the space | interval between the 1st, 2nd joining object members can be controlled with high precision by the electroconductive particle arrange | positioned between the 1st, 2nd joining object members. By controlling the interval between the first and second members to be joined with high accuracy, it is possible to suppress the thickness of the joint portion from being partially reduced, and as a result, the heat dissipation of the joint portion is partially reduced. It can also be suppressed.

  Hereinafter, the present invention will be clarified by describing specific embodiments and examples of the present invention with reference to the drawings.

  FIG. 1 is a cross-sectional view schematically showing a bonded structure using a bonding composition according to an embodiment of the present invention. Note that the structure shown in FIG. 1 is merely an example of the bonded structure according to the present invention, and the bonded structure can be appropriately modified.

  The joining structure 1 shown in FIG. 1 joins the first joining target member 2, the second joining target members 3, 4, and the first joining target member 2 and the second joining target members 3, 4. Connecting portions 5 and 6. The joining parts 5 and 6 are formed using a joining composition containing a joining material containing metal atom-containing particles and conductive particles 21 having a particle diameter CV value of 10% or less.

  The joining portion 5 and the second joining target member 3 are arranged on the first surface 2a (one surface) side of the first joining target member 2. The joining portion 5 joins the first joining target member 2 and the second joining target member 3.

  The joining portion 6 and the second joining target member 4 are disposed on the second surface 2b (the other surface) side opposite to the first surface 2a of the first joining target member 2. The joining portion 6 joins the first joining target member 2 and the second joining target member 4.

  Conductive particles 21 are disposed between the first member 2 and the second members 3, 4, respectively. The joint 5 includes a sintered product 11, and the joint 6 includes a sintered product 12. The sintered bodies 11 and 12 are sintered bodies obtained by sintering the bonding material including the metal atom-containing particles. Sintered materials 11 and 12 are arranged between the first joining target member 2 and the second joining target members 3 and 4. The first joining target member 2 and the second joining target members 3 and 4 are joined by the sintered bodies 11 and 12.

  A heat sink 7 is arranged on the surface opposite to the joint portion 5 side of the second joining target member 3. A heat sink 8 is disposed on the surface of the second joining target member 4 on the side opposite to the joining portion 6 side. Therefore, the bonding structure 1 includes the heat sink 7, the second bonding target member 3, the bonding portion 5, the first bonding target member 2, the bonding portion 6, the second bonding target member 4, and the heat sink 8 stacked in this order. It has the part which was made.

  Examples of the first joining target member 2 include power semiconductor elements used for inverters, converters, and the like. In the joining structure 1 including the first joining target member 2, a large amount of heat is likely to be generated in the first joining target member 2 when the joining structure 1 is used. Therefore, it is necessary to efficiently dissipate the heat generated from the first joining target member 2 to the heat sinks 7 and 8. For this reason, high heat dissipation is calculated | required by the junction parts 5 and 6 arrange | positioned between the 1st joining object member 2 and the heat sinks 7 and 8. FIG.

  Examples of the second bonding target members 3 and 4 include a substrate formed of ceramic, plastic, or the like.

  The joining parts 5 and 6 are formed by heating the joining composition and sintering the metal atom-containing particles.

  When the average thickness of the joints 5 and 6 is T, the average diameter in the thickness direction of the joints 5 and 6 of the conductive particles 21 after joining is preferably 0.6 T or more, more preferably 0.8 T or more. More preferably, it is 0.9T or more, Especially preferably, it is 0.95T or more, Preferably it is 1T or less. When such a thickness relationship is satisfied, the distance between the first and second members to be joined can be controlled with high accuracy. The average thickness of the bonding parts 5 and 6 may be equal to the average diameter of the conductive particles 21 after bonding.

  Examples of the metal atom-containing particles contained in the bonding material include metal particles and metal compound particles. The metal compound particle includes a metal atom and an atom other than the metal atom. Specific examples of the metal compound particles include metal oxide particles, metal carbonate particles, metal carboxylate particles, and metal complex particles. The metal compound particles are preferably metal oxide particles. For example, the metal oxide particles are sintered after becoming metal particles by heating at the time of joining in the presence of a reducing agent. The metal oxide particles are metal particle precursors. Examples of the metal carboxylate particles include metal acetate particles.

  The bonding material including the metal atom-containing particles is a bonding material including metal particles having an average particle diameter of 1 nm or more and 100 nm or less, or reduced with metal oxide particles having an average particle diameter of 1 nm or more and 50 μm or less. It is preferable that the bonding material contains an agent. When such a bonding material is used, the metal atom-containing particles can be satisfactorily sintered by heating during bonding. The average particle diameter of the metal oxide particles is preferably 5 μm or less. The particle diameter of the metal atom-containing particles indicates the diameter when the metal atom-containing particles are spherical, and indicates the maximum diameter when the metal atom-containing particles are not true spherical.

Examples of the metal constituting the metal particle and the metal oxide particle include silver, copper, and gold. Of these, silver or copper is preferable, and silver is particularly preferable. Therefore, the metal particles are preferably silver particles or copper particles, and more preferably silver particles. The metal oxide particles are preferably silver oxide particles or copper oxide particles, and more preferably silver oxide particles. When silver particles and silver oxide particles are used, there are few residues after joining and the volume reduction rate is very small. Examples of the silver oxide in the silver oxide particles include Ag ₂ O and AgO.

  The metal atom-containing particles are preferably sintered by heating at less than 400 ° C. The temperature at which the metal atom-containing particles are sintered (sintering temperature) is more preferably 350 ° C. or lower, and preferably 300 ° C. or higher. When the temperature at which the metal atom-containing particles are sintered is equal to or lower than the above upper limit, the sintering can be efficiently performed, energy required for the sintering can be reduced, and the environmental load can be reduced.

  The content of the metal atom-containing particles in 100% by weight of the bonding material is preferably 10% by weight or more, more preferably 30% by weight or more, still more preferably 50% by weight or more, and 100% by weight or less, preferably 99% by weight. Below, more preferably 90% by weight or less. The total amount of the bonding material may be the metal atom-containing particles. When the content of the metal atom-containing particles is not less than the above lower limit, the metal atom-containing particles can be sintered more densely. As a result, heat dissipation and heat resistance at the joint are also increased.

  When the metal atom-containing particles are metal oxide particles, a reducing agent is preferably used. Examples of the reducing agent include alcohols (compounds having an alcoholic hydroxyl group), carboxylic acids (compounds having a carboxy group), amines (compounds having an amino group), and the like. As for the said reducing agent, only 1 type may be used and 2 or more types may be used together.

  Examples of the alcohols include alkyl alcohols. Specific examples of the alcohols include, for example, ethanol, propanol, butyl alcohol, pentyl alcohol, hexyl alcohol, heptyl alcohol, octyl alcohol, nonyl alcohol, decyl alcohol, undecyl alcohol, dodecyl alcohol, tridecyl alcohol, tetradecyl alcohol. , Pentadecyl alcohol, hexadecyl alcohol, heptadecyl alcohol, octadecyl alcohol, nonadecyl alcohol and icosyl alcohol. The alcohols are not limited to primary alcohol compounds, but secondary alcohol compounds, tertiary alcohol compounds, alkane diols, and alcohol compounds having a cyclic structure can also be used. Furthermore, as the alcohols, compounds having many alcohol groups such as ethylene glycol and triethylene glycol may be used. Moreover, you may use compounds, such as a citric acid, ascorbic acid, and glucose, as said alcohol.

  Examples of the carboxylic acids include alkyl carboxylic acids. Specific examples of the carboxylic acids include butanoic acid, pentanoic acid, hexanoic acid, heptanoic acid, octanoic acid, nonanoic acid, decanoic acid, undecanoic acid, dodecanoic acid, tridecanoic acid, tetradecanoic acid, pentadecanoic acid, hexadecanoic acid, heptadecanoic acid , Octadecanoic acid, nonadecanoic acid and icosanoic acid. The carboxylic acids are not limited to primary carboxylic acid type compounds, but secondary carboxylic acid type compounds, tertiary carboxylic acid type compounds, dicarboxylic acids, and carboxyl compounds having a cyclic structure can also be used.

  Examples of the amines include alkyl amines. Specific examples of the amines include butylamine, pentylamine, hexylamine, heptylamine, octylamine, nonylamine, decylamine, undecylamine, dodecylamine, tridecylamine, tetradecylamine, pentadecylamine, hexadecylamine, Examples include heptadecylamine, octadecylamine, nonadecylamine and icodecylamine. The amines may have a branched structure. Examples of amines having a branched structure include 2-ethylhexylamine and 1,5-dimethylhexylamine. The amines are not limited to primary amine compounds, and secondary amine compounds, tertiary amine compounds, and amine compounds having a cyclic structure can also be used.

  Furthermore, the reducing agent may be an organic substance having an aldehyde group, an ester group, a sulfonyl group, or a ketone group, or may be an organic substance such as a carboxylic acid metal salt. While the carboxylic acid metal salt is used as a precursor of metal particles, it also contains an organic substance, so that it is also used as a reducing agent for metal oxide particles.

  When a reducing agent having a melting point lower than the sintering temperature (joining temperature) of the metal atom-containing particles is used, the reducing agent tends to aggregate at the time of joining and voids are likely to occur at the joint. By using the carboxylic acid metal salt, the carboxylic acid metal salt is not melted by heating at the time of joining, so that the generation of voids can be suppressed. In addition to the carboxylic acid metal salt, a metal compound containing an organic substance may be used as the reducing agent.

  When the reducing agent is used, the content of the reducing agent in 100% by weight of the bonding material is preferably 1% by weight or more, more preferably 10% by weight or more, and preferably 90% by weight or less. Is 70% by weight or less, more preferably 50% by weight or less. When the content of the reducing agent is not less than the above lower limit, the metal atom-containing particles can be sintered more densely. As a result, heat dissipation and heat resistance at the joint are also increased.

  In 100% by weight of the bonding composition, the content of the bonding material is preferably 10% by weight or more, more preferably 30% by weight or more, still more preferably 60% by weight or more, preferably 99.99% by weight or less, and more. It is preferably 99.9% by weight or less, more preferably 99.5% by weight or less, still more preferably 99% by weight or less, particularly preferably 90% by weight or less, and most preferably 80% by weight or less.

  In FIG. 2, the electroconductive particle 21 contained in the composition for joining which concerns on one Embodiment of this invention is shown with sectional drawing.

  As shown in FIG. 2, the conductive particles 21 have base material particles 22 and a conductive layer 23 disposed on the surface 22 a of the base material particles 22. The conductive layer 23 is laminated on the surface 22 a of the base particle 22. The conductive layer 23 covers the surface 22 a of the base particle 22. The conductive layer 23 is a single layer.

  FIG. 3 shows a modification of the conductive particle 21 shown in FIG. The conductive particles 31 shown in FIG. 3 have base material particles 22 and a conductive layer 32 disposed on the surface 22 a of the base material particles 22. The conductive layer 32 is laminated on the surface 22 a of the base particle 22. The conductive layer 32 covers the surface 22 a of the base particle 22. The conductive layer 32 is a multilayer and has a two-layer structure. The conductive layer includes a first conductive layer 32A that is an inner layer and a second conductive layer 32B that is an outer layer. The second conductive layer 32B, which is the outer layer, is disposed on the outer surface of the first conductive layer 32A, which is the inner layer, and covers the outer surface of the first conductive layer 32A.

  The conductive particles may be metal particles, and have conductive particles (conductive particles 21 and 31 shown in FIGS. 2 and 3) having base particles and a conductive layer disposed on the surface of the base particles. Etc.). From the viewpoint of increasing the flexibility of the joint, increasing the flexibility of the conductive particles, allowing the conductive particles to be appropriately compressed and deformed, and further improving the impact resistance of the bonded structure, the above conductivity The particles are preferably conductive particles having resin particles and a conductive layer disposed on the surface of the resin particles. The substrate particles are preferably substrate particles excluding metal, and are preferably organic particles, inorganic particles excluding metal, or organic-inorganic hybrid particles.

  Examples of the resin for forming the resin particles include polyolefin resin, acrylic resin, phenol resin, melamine resin, benzoguanamine resin, urea resin, epoxy resin, unsaturated polyester resin, saturated polyester resin, polysulfone, polyphenylene oxide, and polyacetal. , Polyimide, polyamideimide, polyetheretherketone, polyethersulfone and the like. From the viewpoint of increasing the flexibility of the conductive particles, allowing the conductive particles to be appropriately compressed and deformed, and further improving the impact resistance of the bonded structure, the resin particles are not ethylenically-imparted in the molecule. It is preferably formed of a polymer obtained by polymerizing one or more polymerizable monomers containing a polymerizable monomer having a plurality of saturated groups.

  Examples of the metal for forming the conductive layer include gold, silver, palladium, copper, platinum, zinc, iron, lead, tin, aluminum, cobalt, indium, nickel, chromium, titanium, antimony, germanium, cadmium, Examples thereof include bismuth, thallium, tin-lead alloy, tin-copper alloy, tin-silver alloy, and tin-lead-silver alloy. Further, tin-doped indium oxide (ITO) may be used as the metal. As for the said metal, only 1 type may be used, 2 or more types may be used together, and an alloy may be sufficient as it.

  The method for forming the conductive layer on the surface of the resin particles is not particularly limited. As a method for forming the conductive layer, for example, a method by electroless plating, a method by electroplating, a method by physical vapor deposition, and a surface of base particles such as resin particles such as a metal powder or a paste containing a metal powder and a binder. And the like. Especially, since formation of a conductive layer is simple, the method by electroless plating is preferable. Examples of the method by physical vapor deposition include methods such as vacuum vapor deposition, ion plating, and ion sputtering.

  The average particle diameter of the conductive particles is preferably 1 μm or more, more preferably 2 μm or more, preferably 100 μm or less, more preferably 50 μm or less, still more preferably 30 μm or less, and particularly preferably 10 μm or less. When the average particle diameter of the conductive particles is equal to or more than the above lower limit, the thickness of the joint portion disposed between the first and second members to be joined can be increased, and heat dissipation and joint reliability by the joint portion can be increased. Can be further increased. When the average particle diameter of the conductive particles is not more than the above upper limit, the distance between the electrodes can be reduced, and the joint structure can be reduced in size and thickness. The particle diameter of the conductive particles indicates the diameter when the conductive particles are true spherical, and indicates the maximum diameter when the conductive particles are not true spherical.

  The thickness of the conductive layer is preferably 5 nm or more, more preferably 10 nm or more, still more preferably 50 nm or more, preferably 1000 nm or less, more preferably 500 nm or less, and still more preferably 300 nm or less. When the thickness of the conductive layer is not less than the above lower limit, the conductivity of the conductive particles can be sufficiently increased, and excessive cracking of the conductive layer can be suppressed. As a result of suppressing the cracking of the conductive layer, the thickness of the joint can be made even more uniform, so that the heat dissipation of the joint can be partially prevented from being lowered. When the thickness of the conductive layer is not more than the above upper limit, the stress at the interface due to the difference in thermal expansion coefficient between the base particles such as resin particles and the conductive layer is relaxed, and the conductive layer is peeled off from the base particles such as resin particles. It becomes difficult.

  The outer surface of the conductive layer is preferably a metal containing silver or copper, and more preferably a metal containing silver. The outer surface of the conductive layer is preferably silver or copper, and more preferably silver. When the outer surface of the conductive layer contains silver, the metal atom-containing particles are preferably silver atom-containing particles, and more preferably silver particles or silver oxide particles. When the outer surface of the conductive layer is copper, the metal atom-containing particles are preferably copper atom-containing particles, and more preferably copper particles or copper oxide particles. When the outer surface of the conductive layer is silver or copper and the sintered product constituting the joint is silver or copper, the conductivity and heat dissipation are further improved. When the outer surface of the conductive layer is silver and the sintered product constituting the joint is silver, the conductivity is considerably improved.

  The outer surface of the conductive layer is preferably not melted at 400 ° C. It is possible to suppress deformation of the conductive particles during the sintering of the metal atom-containing particles. For this reason, the space | interval between the 1st, 2nd joining object member can be controlled with higher precision after joining. Furthermore, since the thickness of the joint portion can be made even more uniform, it is possible to suppress a partial decrease in heat dissipation of the joint portion.

  The temperature at which the metal atom-containing particles are sintered is preferably lower than the temperature at which the surface of the conductive particles melts. The temperature at which the metal atom-containing particles are sintered is preferably 5 ° C. or lower, more preferably 10 ° C. or lower, than the temperature at which the surface of the conductive particles melts. When the temperature at which the metal atom-containing particles are sintered and the temperature at which the surfaces of the conductive particles are melted satisfy the above relationship, the conductive particles can be prevented from being deformed during the sintering of the metal atom-containing particles. For this reason, the space | interval between the 1st, 2nd joining object member can be controlled with higher precision after joining. Furthermore, since the thickness of the joint portion can be made even more uniform, it is possible to suppress a partial decrease in heat dissipation of the joint portion.

  The CV value (coefficient of variation in particle size distribution) of the particle diameter of the conductive particles is preferably 10% or less, more preferably 5% or less, and even more preferably 3% or less. When the CV value is less than or equal to the upper limit, the interval between the first and second members to be joined can be controlled with higher accuracy after joining. Furthermore, since the thickness of the joint portion can be made even more uniform, it is possible to suppress a partial decrease in heat dissipation of the joint portion.

  The CV value is represented by the following formula.

CV value (%) = (ρ / Dn) × 100
ρ: standard deviation of particle diameter of conductive particles Dn: average particle diameter

  In 100% by weight of the bonding composition, the content of the conductive particles is preferably 0.01% by weight or more, more preferably 0.1% by weight or more, still more preferably 0.5% by weight or more, particularly preferably. It is 1% by weight or more, preferably 40% by weight or less, more preferably 30% by weight or less, and still more preferably 15% by weight or less. When the content of the conductive particles is equal to or more than the lower limit, the conductive particles can be sufficiently present between the first and second members to be joined, and the first and second conductive particles are used. It can suppress that the space | interval between members to be joined becomes narrow partially. For this reason, it can also suppress that the heat dissipation of a junction part falls partially.

  When the bonding composition is a paste, the binder used for the paste is not particularly limited. The binder preferably disappears when the metal atom-containing particles are sintered. As for the said binder, only 1 type may be used and 2 or more types may be used together.

  Specific examples of the binder include aliphatic solvents, ketone solvents, aromatic solvents, ester solvents, ether solvents, alcohol solvents, paraffin solvents, petroleum solvents, and the like.

  Examples of the aliphatic solvent include cyclohexane, methylcyclohexane, and ethylcyclohexane. Examples of the ketone solvent include acetone and methyl ethyl ketone. Examples of the aromatic solvent include toluene and xylene. Examples of the ester solvent include ethyl acetate, butyl acetate and isopropyl acetate. Examples of the ether solvent include tetrahydrofuran (THF) and dioxane. Examples of the alcohol solvent include ethanol and butanol. Examples of the paraffinic solvent include paraffin oil and naphthenic oil. Examples of the petroleum solvent include mineral terpenes and naphtha.

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

(Bonding material (metal atom-containing particles))
(1) Silver particles having an average particle diameter of 15 nm (2) Copper particles having an average particle diameter of 12 nm (3) Silver oxide (Ag ₂ O) particles having an average particle diameter of 5 μm (4) The average particle diameter is 6 μm Copper oxide (CuO) particles (5) Silver particles having an average particle size of 1 nm (6) Silver particles having an average particle size of 100 nm (7) Copper particles having an average particle size of 1 μm (8) Copper particles having an average particle size of 100 nm (9) average particle diameter 1nm a is silver oxide _(Ag 2 O) particles (10) average particle diameter 50μm at a silver oxide _(Ag 2 O) particles (11) average copper oxide particle size 1nm (CuO) particles ( 12) Copper oxide (CuO) particles having an average particle diameter of 50 μm

(Conductive particles)
(1) Conductive particles A (average particle size 10 μm, a silver layer having a thickness of 300 nm is formed on the surface of divinylbenzene resin particles, CV value 4%)
(2) Conductive particles B (average particle size 10 μm, a silver layer having a thickness of 600 nm is formed on the surface of divinylbenzene resin particles, CV value 4%)
(3) Conductive particles C (average particle size 10 μm, copper layer having a thickness of 300 nm formed on the surface of divinylbenzene resin particles, CV value 4%)
(4) Conductive particles D (average particle size 10 μm, copper layer having a thickness of 600 nm formed on the surface of divinylbenzene resin particles, CV value 4%)
(5) Conductive particles E (average particle diameter 10 μm, copper-palladium alloy layer having a thickness of 300 nm formed on the surface of divinylbenzene resin particles, CV value 4%)
(6) Conductive particles F (average particle size 10 μm, nickel layer having a thickness of 300 nm on the surface of divinylbenzene resin particles and a silver layer having a thickness of 300 nm on the surface of the nickel layer, CV value 4%)
(7) Conductive particles G (average particle size 10 μm, a silver layer having a thickness of 3 nm is formed on the surface of divinylbenzene resin particles, CV value 12%)
(8) Conductive particles H (average particle size 10 μm, silver layer having a thickness of 300 nm formed on the surface of divinylbenzene resin particles, CV value 10%)

(Reducing agent)
(1) Ethanol (2) Butanoic acid

(solvent)
(1) Toluene (2) Ethyl acetate

Example 1
40 parts by weight of silver particles having an average particle diameter of 15 nm, 1 part by weight of conductive particles A, and 40 parts by weight of toluene as a solvent were blended and mixed to obtain a bonding composition.

(Examples 2-18 and Comparative Examples 1-3)
A joining composition was obtained in the same manner as in Example 1 except that the types and contents of the blending components were set as shown in Tables 1 and 2 below.

(Evaluation)
(1) Production of bonded structure A power semiconductor element was prepared as a first bonding target member. An aluminum nitride substrate was prepared as the second member to be joined.

  On the second member to be joined, the joining composition was applied to a thickness of about 30 μm to form a joining composition layer. Then, the said 1st joining object member was laminated | stacked on the composition layer for joining, and the laminated body was obtained. The obtained laminate is heated at 300 ° C. for 10 minutes to sinter the metal atom-containing particles contained in the bonding composition, thereby forming a bonded portion including the sintered product and conductive particles. And the said 1st, 2nd joining object member was joined with this sintered compact, and the joining structure was obtained.

(2) Thickness variation The cross section of the obtained bonded structure was observed to evaluate the minimum thickness and the maximum thickness of the bonded portion. The thickness variation was determined according to the following criteria. In addition, there exists a tendency which can suppress that the heat dissipation of a junction part falls partially, so that thickness dispersion | variation is small.

[Criteria for thickness variation]
○: Maximum thickness is less than 1.2 times the minimum thickness ○: Maximum thickness is 1.2 times or more and less than 1.5 times the minimum thickness ×: Maximum thickness is 1.5 times or more the minimum thickness

(3) Heat dissipation The heat dissipation was evaluated by measuring the thermal resistance of the obtained bonded structure. The heat dissipation was determined according to the following criteria.

[Criteria for heat dissipation]
○○: Less than 0.10 ° C / W ○: 0.10 ° C / W or more, less than 0.30 ° C / W ×: 0.30 ° C / W or more

(4) Joining strength The joining strength (joining reliability) was evaluated by measuring the shear strength of the obtained joined structure. The bonding strength was determined according to the following criteria.

[Judgment criteria for bonding strength]
○○: 10 MPa or more ○: 5 MPa or more, less than 10 MPa ×: less than 5 MPa

(5) Bonding reliability After the obtained bonded structure was allowed to stand at 250 ° C. for 500 hours, the shear strength was measured by the same method as the bonding strength to evaluate the bonding reliability. Bonding reliability was determined according to the following criteria.

[Judgment criteria for bonding reliability]
○○: Shear strength is 0.90 times or more of joint strength ○: Shear strength is 0.60 times or more and less than 0.90 times of joint strength ×: Shear strength is less than 0.60 times of joint strength

(6) Relationship between the average thickness of the joint and the average diameter of the conductive particles By observing a cross section of the obtained bonded structure, the average thickness T of the joint and the joint of the conductive particles after joining The average diameter in the thickness direction was evaluated.

  The results are shown in Tables 1 and 2 below.

DESCRIPTION OF SYMBOLS 1 ... Joining structure 2 ... 1st joining object member 2a ... 1st surface 2b ... 2nd surface 3, 4 ... 2nd joining object member 5, 6 ... Joining part 7, 8 ... Heat sink 11, 12 ... Sintered product 21 ... conductive particles 22 ... base material particles 22a ... surface 23 ... conductive layer 31 ... conductive particles 32 ... conductive layer 32A ... first conductive layer 32B ... second conductive layer

Claims (1)

A joining composition containing a joining material containing metal atom-containing particles, conductive particles having a particle diameter CV value of 10% or less, and a binder is disposed between the first and second joining target members. Process,
Heating the composition for bonding, sintering the metal atom-containing particles, forming a bonded portion, and bonding the first and second bonding target members,
The bonding composition is a paste,
When sintering the metal atom-containing particles, the binder is eliminated,
The first and second members to be joined are joined by a sintered product obtained by sintering the metal atom-containing particles, and the conductive particles are disposed between the first and second members to be joined. Manufacturing method of structure.

Images