WO2009116136A1 - Composite silver nanopaste, process for producing the composite silver nanopaste, and method for bonding the nanopaste - Google Patents

Composite silver nanopaste, process for producing the composite silver nanopaste, and method for bonding the nanopaste Download PDF

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Publication number
WO2009116136A1
WO2009116136A1 PCT/JP2008/054971 JP2008054971W WO2009116136A1 WO 2009116136 A1 WO2009116136 A1 WO 2009116136A1 JP 2008054971 W JP2008054971 W JP 2008054971W WO 2009116136 A1 WO2009116136 A1 WO 2009116136A1
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WO
WIPO (PCT)
Prior art keywords
silver
composite
resin
temperature
paste
Prior art date
Application number
PCT/JP2008/054971
Other languages
French (fr)
Japanese (ja)
Inventor
小松　晃雄
岩黒　弘明
良 松林
Original Assignee
株式会社応用ナノ粒子研究所
新電元工業株式会社
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority to PCT/JP2008/050558 priority Critical patent/WO2009090748A1/en
Application filed by 株式会社応用ナノ粒子研究所, 新電元工業株式会社 filed Critical 株式会社応用ナノ粒子研究所
Priority to JP2010503690A priority patent/JP5256281B2/en
Priority to PCT/JP2008/054971 priority patent/WO2009116136A1/en
Priority to PCT/JP2008/061822 priority patent/WO2009090767A1/en
Priority to JP2010503736A priority patent/JP5306322B2/en
Priority to PCT/JP2008/062238 priority patent/WO2009116185A1/en
Priority to CN2008801281306A priority patent/CN101990474B/en
Priority to EP08870788.0A priority patent/EP2298471B1/en
Priority to KR1020107017975A priority patent/KR101222304B1/en
Priority to PCT/JP2008/073660 priority patent/WO2009090846A1/en
Priority to JP2009549977A priority patent/JP4680313B2/en
Priority to US12/735,435 priority patent/US8348134B2/en
Priority to PCT/JP2008/073751 priority patent/WO2009090849A1/en
Publication of WO2009116136A1 publication Critical patent/WO2009116136A1/en
Priority to US13/707,384 priority patent/US8906317B2/en
Priority to US13/707,298 priority patent/US8459529B2/en

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    • H—ELECTRICITY
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    • H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
    • H01B1/00—Conductors or conductive bodies characterised by the conductive materials; Selection of materials as conductors
    • H01B1/20—Conductive material dispersed in non-conductive organic material
    • H01B1/22—Conductive material dispersed in non-conductive organic material the conductive material comprising metals or alloys
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Definitions

  • the present invention relates to a paste composed of composite silver nanoparticles in which an organic coating layer made of an organic substance is formed around a silver nucleus made of a large number of silver atoms. More specifically, the paste is applied and fired.
  • the present invention relates to a composite silver nanopaste in which the organic coating layer and other organic components are diffused to form a silver film, and a semiconductor bond and an electrode pattern are formed by the silver film, a method for manufacturing the same, and a nanopaste bonding method.
  • solder is an alloy of Sn and Pb, and the use of Pb is being prohibited as a recent environmental preservation measure. Therefore, development of a Pb-free alternative solder that replaces the conventional solder is desired.
  • Patent Document 1 Japanese Patent No. 3205793 was published as Patent Document 1.
  • Silver organic compounds (especially silver organic complexes) were selected as starting materials.
  • the silver organic compound is heated at a temperature higher than or equal to the decomposition start temperature and lower than the complete decomposition temperature in an inert gas atmosphere in which air is shut off, and the coating layer of the silver organic compound is formed around the decomposed and reduced silver core.
  • Composite silver nanoparticles were produced.
  • the particle size of silver nuclei is 1 to 100 nm, and is therefore commonly referred to as composite silver nanoparticles. Specifically, when 100 g of silver stearate was heated at 250 ° C. for 4 hours in a flask under a nitrogen stream, composite silver nanoparticles having a silver nucleus with a particle size of 5 nm were generated.
  • Patent Document 2 The inventor is one of the inventors of this international publication. A plurality of inventions are disclosed in this publication, and among them, a method of treating a metal inorganic compound with a surfactant is important. That is, a first step of colloiding a metal inorganic compound with a surfactant in a non-aqueous solvent to form an ultrafine particle precursor, and a reducing agent is added to the colloidal solution to reduce the ultrafine particle precursor. And a second step of generating composite metal nanoparticles in which a surfactant shell is formed as a coating layer on the outer periphery of the metal core.
  • the above-described method has a feature that since the metal inorganic compound is dissolved in a non-aqueous solvent, the produced composite metal nanoparticles are dispersed in the non-aqueous solvent and are not likely to be in a dumpling state.
  • the added surfactant has a large number of carbon atoms, the number of carbon atoms in the surfactant shell, which is an organic coating layer, is naturally large, and the temperature at which the surfactant shell is baked to disperse, that is, the firing temperature is increased. was there.
  • Patent Document 3 it is described that composite silver nanoparticles are made from silver carbonate and myristic acid (C number is 14). Further, it is described that composite silver nanoparticles were produced from silver carbonate and stearyl alcohol (C number is 18). However, since myristic acid (C number is 14) and stearyl alcohol (C number is 18) have a large carbon number, it goes without saying that there is a disadvantage that the firing temperature for silvering becomes high.
  • the present inventors reacted silver carbonate and decanol (C number 10 alcohol) to produce silver alcoholate-type composite silver nanoparticles composed of decanol residues around the silver nucleus. Succeeded in doing. Similarly, silver carbonate and dodecanol (C12 alcohol) were reacted to successfully produce silver alcoholate-type composite silver nanoparticles composed of dodecanol residues around the silver core.
  • the C number 10 composite silver nanoparticles and the C number 12 composite silver nanoparticles obtained in this way are more silverated than the C number 14 or C number 18 composite silver nanoparticles obtained in Patent Document 3. It goes without saying that the temperature is lowered. As a result of the decrease in the number of carbon atoms, there is an advantage that the silver content increases while the silvering temperature decreases.
  • the present inventors decided to produce a paste using the C number 10 composite silver nanoparticles. Similarly, a paste is prepared using the C number 12 composite silver nanoparticles. Using this paste, a test for fixing the semiconductor on the substrate is performed to confirm the effectiveness of the paste. Regarding the bonding method using paste, there are the following two patent publications.
  • Patent Document 4 composite metal ultrafine particles in which the periphery of a core portion substantially composed of a metal component having an average particle diameter of 1 to 10 nm is coated with a coating layer composed of an organic substance having 5 or more carbon atoms are prepared in advance, and the composite Preparing a metal paste by dispersing metal ultrafine particles in a solvent, attaching the metal paste onto a terminal electrode of a circuit board to form a metal paste ball mainly composed of composite metal ultrafine particles, and the metal There are described a step of bonding electrodes of a semiconductor element on a paste ball using a face-down method and a step of electrically connecting the semiconductor element and a circuit board by low-temperature firing.
  • Japanese Patent No. 3638487 is disclosed.
  • composite metal ultrafine particles in which the periphery of a core portion substantially composed of a metal component having an average particle diameter of 1 to 10 nm is coated with a coating layer composed of an organic substance having 5 or more carbon atoms are prepared in advance.
  • a process of forming a solder bump and a process of heat-sealing the solder bump to a terminal electrode of a circuit board are disclosed.
  • Patent Documents 4 and 5 describe that a metal paste is prepared by dispersing composite metal ultrafine particles in a solvent.
  • claim 3 of Patent Document 4 includes a metal having a high conductivity and a resin component.
  • a metal paste is described.
  • toluene is exemplified as a solvent, and the roles of Patent Documents 4 and 5 are imparted with a role of reducing the viscosity to make the paste into a solution.
  • the resin component is added to increase the viscosity, and an appropriate amount of solvent and resin component is added to produce a paste having a predetermined viscosity.
  • the present inventors also prepared C10 paste by dissolving the above-described C10 composite silver nanoparticles in toluene, and similarly dissolved C12 composite silver nanoparticles in toluene to obtain C12 paste.
  • Both pastes were prepared to have such a viscosity that they would flow naturally when tilted at room temperature so that they could be easily applied to a substrate or a semiconductor electrode.
  • Both pastes were stored in containers at room temperature for only 2 weeks. After storage for 2 weeks, a paste film having a thickness of 1 ⁇ m was formed on the circuit board by screen printing, and baked in an electric furnace at 350 ° C. for 20 minutes to form the paste film into a silver film.
  • the surface and cross section of the silver film were observed using an optical microscope and an electron microscope. As a result, some irregularities were found on the surface of the silver film. In the baking at 350 ° C., all organic substances are diffused, but the silver nuclei are not melted, but the surface is melted and the silver nuclei are sintered to form a silver film. Therefore, if the silver nuclei are large, the surface irregularities will be amplified. That is, it was considered that the unevenness on the surface was formed by sintering between large silver nuclei. The reason for the formation of large silver nuclei is considered to be the result of composite silver nanoparticles agglomerating with each other in the paste to form secondary particles during storage for 2 weeks.
  • the composite silver nanoparticles may have aggregated before the addition of the solvent, and the composite silver nanoparticles were finely ground and monodispersed in advance in a mortar, and then the solvent was added to prepare a paste.
  • a paste film was formed on the circuit board using this paste, and baked at 350 ° C. for 20 minutes. When observed with an electron microscope, the irregularities on the surface of the silver film were somewhat improved, but the irregularities still remained.
  • an object of the present invention is to provide a technology for pasting C10 or C12 composite silver nanoparticles in a form that does not aggregate, that is, a non-aggregating paste, and a non-fluidic pace that realizes the non-aggregating property by non-fluidity. Is to provide. Moreover, it is providing the manufacturing method of the non-fluid paste, and providing the joining method using a non-fluid paste simultaneously.
  • the present invention has been made in order to solve the above problems, and the first form of the present invention is an alcohol molecule residue having either 10 or 12 carbon atoms around a silver nucleus composed of an aggregate of silver atoms.
  • a composite silver nanoparticle formed with an organic coating layer composed of one or more alcohol molecule derivatives and / or alcohol molecules, silver fine particles, and a resin are mixed, and the resin is in a non-flowing state at 30 ° C. or less.
  • It is a composite silver nanopaste in which the composite silver nanoparticles and the silver fine particles are kept in a uniformly dispersed state and fluidized by heating and can be applied.
  • the resin of the present invention refers to a substance that is in a non-flowing state at 30 ° C.
  • the non-flowing state is a concept including both a solid state and a high viscosity state.
  • it refers to a substance that is evaporated or decomposed by high-temperature heating and has no residue such as carbonization or a small amount of residue.
  • the concept of resin is consistent throughout the specification. Therefore, the resin of the present invention is different from the resin of the general chemical concept.
  • a second aspect of the present invention is a composite silver nanopaste according to the first aspect, wherein the average particle diameter of the silver nuclei is 1 to 20 nm and the average particle diameter of the silver fine particles is 0.1 to 3.0 ⁇ m. is there.
  • the weight of the composite silver nanoparticles is 5 to 30 (wt%), the weight of the silver fine particles is 60 to 90 (wt%),
  • the composite silver nanopaste has a resin weight of 15 (wt%) or less.
  • the fourth form of the present invention is a composite silver nanopaste having a silver content of 80 (wt%) or more as a whole in the third form.
  • a fifth form of the present invention is a composite silver nanopaste according to any one of the first to fourth forms, wherein a desired amount of a solvent is added to make it flowable even at 30 ° C. or less and can be applied.
  • a sixth aspect of the present invention is the method according to any one of the first to fifth aspects, wherein the silver film is formed by applying to a substrate and baking at a temperature of 250 to 500 ° C. in a nitrogen atmosphere to disperse the organic matter.
  • the composite silver nanopaste has a bonding area ratio between the silver film and the substrate of 70% or more and a specific resistance of the silver film of 10 ( ⁇ cm) or less.
  • an organic coating layer comprising at least one alcohol molecule residue, alcohol molecule derivative and / or alcohol molecule having 10 or 12 carbon atoms around a silver nucleus composed of an aggregate of silver atoms. Is added to a predetermined amount of resin that is in a non-flowing state at 30 ° C. or less and fluidized by heating, and kneaded until the resin is uniformly dispersed at a temperature at which the resin is in a flowing state.
  • a predetermined amount of silver fine particles is added to a predetermined amount of resin that is in a non-flowing state at 30 ° C. or less and fluidized by heating, and is uniformly dispersed at a temperature at which the resin is in a flowing state.
  • a paste intermediate is formed by kneading, and an alcohol molecule residue, alcohol molecule derivative and / or alcohol molecule having either 10 or 12 carbon atoms is disposed around the silver nucleus composed of an aggregate of silver atoms.
  • a predetermined amount of composite silver nanoparticles formed with an organic coating layer composed of one or more of the above are added and kneaded until uniformly dispersed at the temperature, cooled to a temperature at which the resin becomes non-flowable after kneading, and the composite
  • This is a method for producing a composite silver nanopaste in which silver nanoparticles and silver fine particles are maintained in a uniformly dispersed state in the resin.
  • an organic coating layer composed of one or more alcohol molecule residues, alcohol molecule derivatives or alcohol molecules having 10 or 12 carbon atoms is formed around a silver nucleus composed of an aggregate of silver atoms.
  • a fixed amount of composite silver nanoparticles and a predetermined amount of silver fine particles are added to a predetermined amount of resin that is in a non-flowing state at 30 ° C. or less and fluidized by heating, and is uniformly dispersed at a temperature at which the resin is in a flowing state.
  • This is a method for producing a composite silver nanopaste, which is kneaded and cooled to a temperature at which the resin becomes non-flowing after kneading to keep the composite silver nanoparticles and the silver fine particles in a uniformly dispersed state in the resin.
  • a tenth aspect of the present invention is the composite according to any one of the seventh to ninth aspects, wherein the average particle diameter of the silver nuclei is 1 to 20 nm and the average particle diameter of the silver fine particles is 0.1 to 3.0 ⁇ m. It is a manufacturing method of silver nano paste.
  • the predetermined amount of the composite silver nanoparticles is 5 to 30 (wt%), and the predetermined amount of the silver fine particles is 60 to 90 ( wt%), the predetermined amount of the resin is 15 (wt%) or less, and the overall silver content is 80 (wt%) or more.
  • a twelfth aspect of the present invention is the composite silver nanopaste according to any one of the seventh to eleventh aspects, wherein a desired amount of a solvent is added to make a paste that can be applied by being fluidized at 30 ° C. or lower. It is a manufacturing method.
  • a composite silver nanopaste in a fluid state of any one of the first to sixth forms is prepared, and the composite silver nanopaste is applied onto a lower substrate to form a bonding paste layer.
  • the fourteenth aspect of the present invention is the nanopaste bonding method according to the thirteenth aspect, wherein the upper substrate is a semiconductor element.
  • an organic substance composed of one or more alcohol molecule residues, alcohol molecule derivatives and / or alcohol molecules having 10 or 12 carbon atoms around a silver nucleus composed of an aggregate of silver atoms. Since composite silver nanoparticles having a coating layer are used, an inexpensive composite silver nanopaste can be provided.
  • the composite silver nanopaste uses, for example, relatively inexpensive silver carbonate and alcohol as starting materials, and uses a relatively inexpensive alcohol having 10 or 12 carbon atoms, so that inexpensive composite silver nanoparticles can be used. .
  • it is C10 or C12, the number of carbon atoms is relatively small, and the silver content in the composite silver nanoparticles is relatively high.
  • C10 means decanol
  • C12 means dodecanol. That is, a composite silver nanoparticle having an organic coating layer composed of a large number of C10 alcoholate groups around a silver nucleus that is an aggregate of silver atoms is written as C10AgAL, and a composite silver having an organic coating layer composed of a large number of C12 alcoholate groups The nanoparticles are written as C12AgAL.
  • the alcohol residue is a concept including, for example, an alcoholate group CnH2n + 1O when the alcohol is written as CnH2n + 1OH.
  • the alcohol derivative is a concept including, for example, carboxylic acid. Alcohol refers to CnH2n + 1OH itself.
  • the silver fine particles have a particle size of submicron to micron size, and the composite silver nanoparticles are considered to play a role of an adhesive between the silver fine particles. It is a main component of silver containing silver fine particles.
  • the composite silver nanoparticles adhere to the surface of the silver fine particles, the organic components are diffused by firing, and the silver fine particles whose surfaces are melted are bonded to each other.
  • the resin has the greatest feature.
  • the resin has a property of being in a non-flowing state at 30 ° C. or less, holding the composite silver nanoparticles and the silver fine particles in a dispersed state, and fluidizing by heating.
  • the non-flowing state means a solid state or a high-viscosity state, and refers to a property of holding the composite silver nanoparticles and the silver fine particles fixedly in a dispersed state.
  • the temperature of 30 ° C. or lower is usually in the room temperature region, and when stored at room temperature, the paste is in a non-flowing state, and composite silver nanoparticles and silver fine particles dispersed inside are fixed in the paste by a resin, It cannot aggregate. That is, when the paste of the present invention is stored for a long time at a room temperature of 30 ° C. or lower, since the resin is in a non-flowing state, the silver fine particles and the composite silver nanoparticles are held in a fixed state in the resin, and the particles aggregate together.
  • This non-flowable paste can be referred to as a non-cohesive paste.
  • the resin when heated to 40 ° C. or higher, the resin is liquefied or the viscosity is suddenly lowered to be in a fluid state, and can be applied to an object as a paste. Accordingly, after the paste of the present invention is produced, it is stored at 30 ° C. or lower to be non-aggregated (non-fluidized). Just before applying the paste to the object, it is heated and fluidized to make a fluid paste, and if this fluid paste is applied to the object, the metal (silver) is not agglomerated so it is extremely dense.
  • a silver film can be formed. If the remaining fluid paste is immediately cooled to 30 ° C. or less, it can be stored for a long time as a non-aggregating paste.
  • the resin that changes from a high viscosity to a low viscosity by heating include isobornylcyclohexanol (referred to as rosin) and glycerin (referred to as syrup).
  • rosin isobornylcyclohexanol
  • syrup glycerin
  • resins that are solid at 30 ° C. or lower and liquefy when heated alcohols such as myristyl alcohol (C14), palmityl alcohol (C16), stearyl alcohol (C18), and behenyl alcohol (C22), and other substances can be used. .
  • These resins must have the property that all components are diffused when baked or there are very few residues such as carbides, and due to this property the electrical conductivity of the silver film formed by calcination And thermal conductivity can be greatly improved.
  • a dispersant is added to disperse the composite silver nanoparticles, or a surfactant is added.
  • a dispersant is added to disperse the composite silver nanoparticles, or a surfactant is added.
  • these impurity organic substances are added, not only the silver content is lowered, but also when fired, A large amount of gas is generated from the impurity organic substance, and a large amount of voids (bubble voids) are formed in the silver film by this gas.
  • the electrical conductivity is lowered and the bonding force with the substrate is lowered. Bonding performance is reduced.
  • the silver content can be kept high, and at the same time, the amount of generated gas is small, the number of voids is inevitably reduced, the increase in bonding force and electrical conductivity and There is an effect that the thermal conductivity can be increased.
  • the average particle diameter of the silver nuclei is 1 to 20 nm, and the average particle diameter of the silver fine particles is 0.1 to 3.0 ⁇ m.
  • the gap between the silver fine particles is filled with silver nuclei, and the silver fine particles are bonded to each other by the silver nuclei.
  • a conductor that is densely formed and has high strength and high electrical conductivity is provided.
  • the particle size relationship is as described above, the silver nuclei fill the gaps between the silver fine particles, and the gas nuclei are filled back into the bubble cavities (voids), and the number of voids is reduced. As a result, it is possible to improve the bonding strength and electrical conductivity with the substrate.
  • the weight of the composite silver nanoparticles is 5 to 30 (wt%), the weight of the silver fine particles is 60 to 90 (wt%), and the weight of the resin is 15 (wt %) Or less, a composite silver nanopaste with a high silver content can be provided.
  • the weight of the composite silver nanoparticle serving as an adhesive is 5 (wt%) or less, the adhesive strength between the silver fine particles is small, and when it is 30 (wt%) or more, the paste becomes expensive and the amount of organic matter is large. As a result, the amount of voids is slightly increased.
  • the composite silver nanoparticles are C10 or C12, the silver content is relatively high as described above.
  • the silver fine particles occupying the maximum weight are pure silver, the silver content in the entire paste can be further increased, and the electrical conductivity can be increased.
  • the weight of the silver fine particles is 60 (wt%) or less, the silver content is relatively lowered.
  • the weight is 90 (wt%) or more, the composite silver nanoparticles serving as an adhesive are reduced, and the adhesive strength between the silver particles is reduced.
  • the organic resin is as small as 15 wt% or less, the organic content is low, and when the paste film is baked, less gas is generated and less voids (bubble cavities) remain afterwards. Naturally, the higher the silver content, the less gas is generated and the fewer voids. The smaller the voids, the larger the bonding area ratio between the silver film and the substrate, and it is possible to form a silver film with high electrical conductivity and high bonding strength.
  • a composite silver nanopaste having a silver content of 80 (wt%) or more as a whole can be provided.
  • the silver content is less than 80 (wt%), the organic content becomes 20 (wt%) or more, the amount of gas generated during firing increases, the amount of voids increases, and effective bonding strength and electrical conduction. The degree cannot be obtained.
  • the silver content is preferably 85 (wt%) or more, most preferably 90 (wt%) or more, and can provide an innovative paste in the fields of semiconductor bonding and pattern formation.
  • a composite silver nanopaste that can be applied by adding a desired amount of solvent to make it flowable even at 30 ° C. or lower.
  • a paste to which only a resin is added is provided, and even if the paste is stored at 30 ° C. or lower, the paste does not have fluidity. They are fixed and do not cause mutual aggregation, and are non-aggregating pastes.
  • the solvent of the fifth embodiment is added and fluidized, and the fluid paste is applied to the substrate by a dispenser. be able to.
  • a composite silver nanopaste having a bonding area ratio of 70% or more and a specific resistance of the silver film of 10 ( ⁇ cm) or less can be provided.
  • Research by the present inventors has revealed that, when baked in a nitrogen atmosphere, the organic matter in the paste is not oxidized and the organic matter is evaporated and diffused by heating.
  • the alcoholate group bonded around the silver nucleus evaporates from the silver nucleus by the alcoholate group alone and hardly decomposes.
  • the resin component In a nitrogen atmosphere, the resin component is also evaporated and diffused without being decomposed by heating. Since it is not decomposed, the amount of gas generated is small, and the amount of void generation is inevitably small. As a result, the bonding area ratio between the silver film and the substrate is increased, and at the same time, the effect of increasing the bonding strength and electrical conductivity is obtained. Therefore, in a nitrogen atmosphere, if the bonding area ratio between the silver film and the substrate is 70% or more, the specific resistance of the silver film can be adjusted to 10 ( ⁇ cm), and preferably the bonding area ratio is 80% or more.
  • the specific resistance can be reduced to, for example, 8 ( ⁇ cm) or less, and more preferably, the specific resistance is decreased to, for example, 5 ( ⁇ cm) or less by setting the junction area ratio to 90% or more. It is possible to approach the specific resistance.
  • the evaporation temperature of the organic substance is lower than the oxidation temperature by air, there is an advantage that the firing temperature can be lowered and firing at a low temperature is possible as compared with firing in air.
  • the organic matter is oxidized in firing in the air, the organic matter is decomposed and diffused as CO2 or H2O. As a result, 1 mol of organic matter increases to 2 mol and 3 mol, and a large amount of gas is generated to generate voids.
  • the amount of generation increases so that it cannot be compared with that in a nitrogen atmosphere.
  • the amount of gas generated can be suppressed under a nitrogen atmosphere, the number of voids can be reduced, the bonding area ratio can be increased, and the bonding strength and electrical conductivity can be increased.
  • the organic substance evaporates as organic molecules, and thus evaporates while absorbing the heat of evaporation, so it may be locally cooled in the paste and the heat of the remaining silver nuclei. It is considered that the vibration is small and the silver nuclei slowly move into the gaps between the silver fine particles, contributing to the densification of the silver film and the reduction in the number of voids.
  • heat is generated by the oxidation reaction of organic matter, and this generated heat accelerates the thermal vibration of the silver nuclei, so that the silver nuclei do not move so as to fill the gaps between the silver fine particles. Conceivable. Therefore, it can be said that firing in a nitrogen atmosphere is more effective in densifying the silver film and reducing the number of voids, and improving the bonding strength and electrical conductivity than firing in the air.
  • an organic substance comprising at least one alcohol molecule residue, alcohol molecule derivative and / or alcohol molecule having 10 or 12 carbon atoms around a silver nucleus composed of an aggregate of silver atoms.
  • a predetermined amount of composite silver nanoparticles having a coating layer added thereto is added to a predetermined amount of resin that is in a non-flowing state at 30 ° C. or less and fluidized by heating, and is kneaded until uniformly dispersed at a temperature at which the resin is in a flowing state.
  • a method of producing a non-aggregating composite silver nanopaste that maintains the composite silver nanoparticles and the silver fine particles in a uniformly dispersed state in the resin can be provided.
  • the heating temperature is a temperature at which the resin is fluidized, and is adjusted below the temperature at which the organic matter does not evaporate.
  • the paste temperature rises due to frictional heat during kneading. For example, if it rises to about 40 ° C, the paste will naturally flow and uniform kneading becomes possible. (Natural heating) can be fluidized. Further, when the composite silver nanoparticles and the resin are kneaded first, the nano-sized composite silver nanoparticles are easily dispersed uniformly in the resin. Thereafter, when micron-sized silver fine particles are added and kneaded, the silver fine particles are uniformly dispersed in the resin, and it is easy to make a paste in which the resin, the composite silver nanoparticles, and the silver fine particles are independently and uniformly dispersed.
  • a known mixing device can be used for the kneading method, and not only a rotating centrifuge but also a rotating / revolving centrifuge can be used.
  • a predetermined amount of silver fine particles is added to a predetermined amount of resin that is in a non-flowing state at 30 ° C. or less and fluidized by heating, and is uniformly dispersed at a temperature at which the resin is in a flowing state. Kneading until a paste intermediate is formed, and the paste intermediate is surrounded by an alcohol molecule residue, alcohol molecule derivative and / or carbon atom having either 10 or 12 carbon atoms around a silver nucleus composed of an aggregate of silver atoms.
  • a method of producing a non-aggregating composite silver nanopaste that maintains the composite silver nanoparticles and the silver fine particles in a uniform dispersed state in the resin can be provided.
  • the heating temperature is a temperature at which the resin is fluidized, and is adjusted below the temperature at which the organic matter does not evaporate.
  • the paste temperature rises due to frictional heat during kneading. For example, if it rises to about 40 ° C, the paste will naturally flow and uniform kneading becomes possible. (Natural heating) can be fluidized.
  • the silver fine particles and the resin are kneaded first, the micron-sized silver fine particles are easily dispersed uniformly in the resin. After this, when nano-sized composite silver nanoparticles are added and kneaded, the composite silver nanoparticles are uniformly dispersed in the resin, and the three of the resin, silver fine particles, and composite silver nanoparticles are independently and uniformly dispersed. Easy to make. Needless to say, a known mixing device can be used for the kneading method, and not only a rotating centrifuge but also a rotating and rotating centrifuge can be used.
  • an organic coating layer composed of one or more alcohol molecule residues, alcohol molecule derivatives or alcohol molecules having 10 or 12 carbon atoms is formed around a silver nucleus composed of an aggregate of silver atoms.
  • a predetermined amount of composite silver nanoparticles and a predetermined amount of silver fine particles are added to a predetermined amount of resin that is in a non-fluid state at 30 ° C.
  • Manufacturing method can be provided. In this method, the composite silver nanoparticles, the silver fine particles, and the resin are kneaded together at the same time, so that the time required for kneading can be shortened.
  • the heating method may be either forced heating or friction heating by kneading as long as the fluidization of the resin is manifested.
  • a known mixing device can be used for the kneading method, and not only a rotating centrifuge but also a rotating / revolving centrifuge can be used.
  • a method for producing a composite silver nanopaste having an average particle size of the silver nuclei of 1 to 20 nm and an average particle size of the silver fine particles of 0.1 to 3.0 ⁇ m. Since the composite silver nanoparticles are nano-sized and the silver fine particles are micron-sized, if they are uniformly dispersed and mixed, the composite silver nanoparticles will be located between the silver fine particles even in a non-flowable paste (ie, non-aggregating paste). In this structure, the silver nuclei reliably fill the gaps between the silver fine particles. In addition, the silver nuclei naturally move back into the bubble cavities (voids) after the gas has diffused, and the number of voids is reduced. As a result, the bonding area ratio with the substrate, bonding strength, and electrical conduction It is possible to improve the degree.
  • the predetermined amount of the composite silver nanoparticles is 5 to 30 (wt%), the predetermined amount of the silver fine particles is 60 to 90 (wt%), and the predetermined amount of the resin Is 15 (wt%) or less, and a method for producing a composite silver nanopaste having an overall silver content of 80 (wt%) or more is provided.
  • the weight of the composite silver nanoparticle serving as an adhesive is 5 (wt%) or less, the adhesive strength between the silver fine particles is small, and when it is 30 (wt%) or more, the paste becomes expensive and the amount of organic matter is large. As a result, the amount of voids is slightly increased.
  • the composite silver nanoparticles are C10 or C12, the silver content is relatively high as described above. Further, since the silver fine particles occupying the maximum weight are pure silver, the silver content in the entire paste can be further increased, and the electrical conductivity can be increased. When the weight of the silver fine particles is 60 (wt%) or less, the silver content is relatively lowered. When the weight is 90 (wt%) or more, the composite silver nanoparticles serving as an adhesive are reduced, and the adhesive strength between the silver particles is reduced. Tends to decrease. Since the organic resin is as small as 15 wt% or less, the organic content is low, and when the paste film is baked, less gas is generated and less voids (bubble cavities) remain afterwards.
  • the manufacturing method of the composite silver nanopaste whose silver content rate is 80 (wt%) or more as a whole can be provided.
  • the silver content is less than 80 (wt%), the organic content becomes 20 (wt%) or more, the amount of gas generated during firing increases, the amount of voids increases, and effective bonding strength and electrical conduction. The degree cannot be obtained.
  • the silver content is preferably 85 (wt%) or more, most preferably 90 (wt%) or more, and can provide an innovative paste in the fields of semiconductor bonding and pattern formation.
  • a method for producing a composite silver nanopaste that is made into a paste that can be applied by adding a desired amount of a solvent to make it flowable at 30 ° C. or lower.
  • a desired amount of a solvent to make it flowable at 30 ° C. or lower.
  • the paste does not have fluidity. Therefore, the composite silver nanoparticles and silver fine particles are fixed in the non-flowable paste, and are mutually agglomerated. It is possible to realize a non-cohesive paste that does not generate odor.
  • the solvent of this embodiment can be added and fluidized, and the flowable paste can be applied to the substrate by a dispenser.
  • a solvent is added, the organic matter content in the paste increases, so there is a weak point that the amount of gas generated by firing increases and the amount of void generation increases.
  • a solvent is added immediately before coating, it is possible to avoid the composite silver nanoparticles from aggregating into secondary particles (ie, dumpling).
  • a composite silver nanopaste in a fluidized state is prepared, the composite silver nanopaste is applied onto the lower substrate to form a bonding paste layer, and / or the bonding
  • a nanopaste bonding method in which an upper substrate is placed on a paste layer to form a bonded body, and the bonded body is fired at a temperature of 250 to 500 ° C. in a nitrogen atmosphere and / or under no load.
  • an electrode pattern or conductor pattern
  • an upper substrate when placed on the bonding paste layer to form a bonded body and fired, it means a case where the lower substrate and the upper substrate are bonded with a conductor.
  • This form includes both.
  • Research by the present inventors has revealed that, when baked in a nitrogen atmosphere, the organic matter in the paste is not oxidized and the organic matter is evaporated and diffused by heating.
  • the alcoholate group bonded around the silver nucleus evaporates from the silver nucleus by the alcoholate group alone and hardly decomposes.
  • the resin component In a nitrogen atmosphere, the resin component is also evaporated and diffused without being decomposed by heating.
  • the amount of gas generated is small, and the amount of void generation is inevitably small.
  • the bonding area ratio between the silver film and the substrate increases, and at the same time, the effect of increasing the bonding strength and electrical conductivity can be obtained.
  • the evaporation temperature of the organic substance is lower than the oxidation temperature by air, there is an advantage that the firing temperature can be lowered and firing at a low temperature is possible as compared with firing in air.
  • the organic matter is oxidized in firing in the air, the organic matter is decomposed and diffused as CO2 or H2O.
  • the organic substance evaporates as organic molecules, and thus evaporates while absorbing the heat of evaporation, so it may be locally cooled in the paste and the heat of the remaining silver nuclei. It is considered that the vibration is small and the silver nuclei slowly move into the gaps between the silver fine particles, contributing to the densification of the silver film and the reduction in the number of voids.
  • heat is generated by the oxidation reaction of organic matter, and this generated heat accelerates the thermal vibration of the silver nuclei, so that the silver nuclei do not move so as to fill the gaps between the silver fine particles. Conceivable.
  • firing in a nitrogen atmosphere is more effective in densifying the silver film and reducing the number of voids, and improving the bonding strength and electrical conductivity than firing in the air.
  • the joining can be performed while applying a load, but it was confirmed that sufficient joining can be performed even under no load. That is, it was found that the bonding area ratio, bonding strength, and electrical conductivity can be realized within a specified range even under no load.
  • the range of the firing temperature is 250 to 500 ° C., and it was confirmed that sufficient bonding can be realized by using the paste of the present invention even at a low temperature firing of 250 ° C. or a high temperature firing of 500 ° C. This means that a junction that can withstand practical use can be realized even at a temperature during that time, that is, an intermediate temperature junction, which has been experimentally confirmed.
  • the nanopaste bonding method wherein the upper substrate is a semiconductor element.
  • the upper substrate is a semiconductor element.
  • a semiconductor element as an upper substrate is bonded to a circuit board as a lower substrate with a bonding paste layer.
  • a bonding paste layer There are various joining forms other than this example.
  • a circuit can be mounted on the substrate.
  • FIG. 1 is a production process diagram of composite silver nanoparticles CnAgAL.
  • FIG. 2 is a first process diagram of a formation reaction of composite silver nanoparticles.
  • FIG. 3 is a second process diagram of the formation reaction of composite silver nanoparticles.
  • FIG. 4 is a high-resolution transmission electron microscope view of C10AgAL.
  • FIG. 5 is a high-resolution transmission electron microscope view of C12AgAL.
  • FIG. 6 is a graph showing the relationship between the particle size and melting point of silver particles.
  • FIG. 7 is a thermal analysis diagram of C12AgAL.
  • FIG. 8 is a production process diagram of a composite silver nanopaste.
  • FIG. 9 is a characteristic diagram of viscosity and temperature of IBCH resin.
  • FIG. 9 is a characteristic diagram of viscosity and temperature of IBCH resin.
  • FIG. 10 is a thermal analysis diagram of IBCH resin with a temperature increase rate of 3 ° C./min.
  • FIG. 11 is a relationship diagram between the evaporation temperature of the IBCH resin and the temperature rise rate.
  • FIG. 12 is a characteristic diagram of viscosity and temperature of glycerin resin.
  • FIG. 13 is a thermal analysis diagram of the composite silver nanopaste (P5).
  • FIG. 14 is a relationship diagram of the bonding area ratio and silver content of various nanopastes.
  • FIG. 15 is a joint diagram of the nanopaste (P12) with the glass surface.
  • FIG. 16 is a bonding diagram of the nanopaste (P16) with the Cu surface.
  • FIG. 17 is a bonding diagram of the nanopaste (P19) to the glass surface.
  • FIG. 18 is a temperature time relationship diagram in the paste firing temperature raising program.
  • FIG. 19 is a thermal analysis diagram of the nanopaste (P20-2) in air firing.
  • FIG. 20 is a thermal analysis diagram of baking of the nanopaste (P20-2) in nitrogen.
  • FIG. 21 is a thermal analysis diagram in the air firing of the nanopaste (P21).
  • FIG. 22 is a thermal analysis diagram in the firing of the nanopaste (P21) in nitrogen.
  • FIG. 23 is a thermal analysis diagram in the air firing of the nanopaste (P22).
  • FIG. 24 is a thermal analysis diagram in baking of the nanopaste (P22) in nitrogen.
  • FIG. 25 is a thermal analysis diagram of the nanopaste (P23) in air firing.
  • FIG. 26 is a thermal analysis diagram in the firing of the nanopaste (P23) in nitrogen.
  • FIG. 27 is a comparison diagram of TG thermal analysis of nano pastes (P20-2, P21, P23) in nitrogen and air firing.
  • FIG. 28 is a production process diagram of a diode resin mold for a bonding test.
  • FIG. 29 is a bonding test measurement diagram of VF and ⁇ VF of the diode resin molded body.
  • FIG. 30 is a comparison diagram of VF when various pastes are fired in air and nitrogen.
  • FIG. 31 is a comparative diagram of ⁇ VF when various pastes are fired in air and nitrogen.
  • FIG. 32 is a comparison diagram of VF after the initial reflow heat test in the firing of various pastes in the air.
  • FIG. 33 is a comparative diagram of ⁇ VF after the initial reflow heat test in the air firing of various pastes.
  • FIG. 34 is a comparison diagram of VF after the initial reflow heat test in firing various pastes in nitrogen.
  • FIG. 35 is a comparative view of ⁇ VF after the initial and reflow heat test in firing various pastes in nitrogen.
  • Table 1 is a list of raw materials for producing composite silver nanoparticles used in the present invention.
  • Silver carbonate (Ag2CO3) is used as the silver raw material
  • decanol (C10H21OH) and dodecanol (C12H25OH) are used as the alcohol raw material.
  • the molecular weight, boiling point and melting point of the alcohol are as indicated.
  • FIG. 1 is a production process diagram of composite silver nanoparticles.
  • a mixed solution of a predetermined amount of Ag2CO3 powder and a predetermined amount of alcohol is prepared, and the mixed solution is sealed in a reaction vessel.
  • the mixture is heated at a generation temperature T (° C.) for a predetermined time under an Ar gas flow.
  • T generation temperature
  • the reaction time is preferably within 1 hour.
  • the composite silver nanoparticles start to aggregate with each other and become secondary particles. Therefore, it is desirable to cool rapidly after the reaction.
  • the composite silver nanoparticles are recovered from the reaction solution as a powder.
  • the composite silver nanoparticle is expressed as CnAgAL, and indicates that it is a silver alcoholate-type composite silver nanoparticle.
  • FIG. 2 is a first process diagram of the formation reaction of composite silver nanoparticles according to the present invention.
  • Rn in the formula (3) represents a hydrocarbon group of alcohol.
  • the carbon number n is limited to 10 or 12.
  • the hydrophilic group OH of the alcohol has a property of easily bonding to the surface of the silver carbonate fine particles.
  • the hydrophobic group Rn of alcohol has high affinity with the alcohol solvent. Therefore, as shown in the formula (4), when the silver carbonate fine particles are dispersed in an alcohol solvent, the alcohol surrounds the surface of the silver carbonate fine particles, and a stable silver carbonate fine particle colloid is formed.
  • FIG. 3 is a second process diagram of a formation reaction of composite silver nanoparticles according to the present invention.
  • Silver carbonate on the surface of the silver carbonate fine particles reacts with alcohol to form aldehyde R n-1 CHO simultaneously with silveration, as shown in formula (5).
  • aldehyde has a strong reducing action, and as shown in formula (7), silver carbonate is reduced to form carboxylic acid R n-1 COOH simultaneously with silveration.
  • FIG. 4 is a high-resolution transmission electron microscope diagram of C10AgAL.
  • a lattice image was observed in the silver nucleus, and it was confirmed that the silver nucleus was a single crystal of silver from the lattice spacing.
  • FIG. 5 is a high-resolution transmission electron microscope view of C12AgAL.
  • FIG. 6 is a graph showing the relationship between the silver particle size and the melting point. This relationship diagram is excerpted from Ph. Buffat and J-P. Borel, Phy. Rev. A13 (1976) 2287 (Non-patent Document 1).
  • the melting point rapidly decreases as the particle size of the silver particles decreases, and reaches 740 ° C. when the particle size is 5 (nm) and 365 ° C. when the particle size is 2 (nm).
  • the melting point in this paper is the temperature at which the silver particles melt completely.
  • the firing temperature in the present invention is the sintering temperature of silver nuclei, it is surface melting of silver nuclei and does not mean complete melting of silver nuclei.
  • the metallization temperature T3 (° C.) of composite silver nanoparticles having an average particle size of 5 (nm), which will be described later, is 200 to 300 ° C.
  • Table 2 is a list of types and physical properties of the composite silver nanoparticles used in the present invention.
  • C10AgAL was produced with a production temperature T of 120 ° C. and a production time of 22 minutes.
  • the DTA peak temperature T2 (° C.) is the temperature of the final reaction peak that appears after the exothermic reaction is started, and is also referred to as a decomposition temperature, which is a temperature at which organic substances are strongly diffused.
  • the metallization temperature T3 (° C.) is a temperature at which the decomposition ends and the reaction peak disappears, and is also a temperature at which silver nuclei are exposed. It is shown that the lower the DTA peak temperature T2 (decomposition temperature), the lower the metallization temperature T3.
  • FIG. 7 is a thermal analysis diagram of C12AgAL in air and nitrogen gas.
  • T2 decomposition temperature
  • T3 metallization temperature
  • a sharp exothermic peak is not observed, and a constant value is reached at about 220 ° C. through a slow step, which is considered to be the metallization temperature T3.
  • the TG in the air showing the weight curve drops to a constant value earlier than the TG in nitrogen.
  • the alcoholate group gradually diffuses from the composite silver nanoparticles, and the TG reaches a constant value when the entire amount of the organic matter is diffused.
  • the temperature at which the constant value has been reached is the metallization temperature T3. This temperature should coincide with the temperature at which the DTA has reached a constant value, but it is important to determine by expanding TG.
  • FIG. 8 is a production process diagram of composite silver nanopaste.
  • a predetermined weight percent of composite silver nanoparticle CnAgAL powder, a predetermined weight percent of silver fine particle Ag powder, and a predetermined weight percent of resin are prepared, and these three components are put into a mixing container.
  • the resin is fluidized by heating to 40 ° C. in a mixing container, and the paste is uniformly mixed.
  • a rotation-revolution centrifuge that performs rotation at 700 rpm and revolution at 2000 rpm was used. If the heating temperature is about 40 ° C., the temperature is naturally raised by frictional heat, and therefore a forced heating operation is unnecessary. However, when it is 40 ° C. or higher, it can be efficiently fluidized by heating with a heater. Thereafter, the composite silver nanopaste is rapidly cooled and solidified and recovered. By solidification, the uniformly dispersed composite silver nanoparticles and silver fine particles are fixed by the resin and do not aggregate during storage.
  • a method in which the manufacturing process of FIG. 8 is modified is also adopted.
  • a paste intermediate is produced by mixing a predetermined weight% of composite silver nanoparticles CnAgAL powder and a predetermined weight% of resin while heating.
  • a predetermined weight percent of silver fine particle Ag powder is uniformly mixed with this paste intermediate while heating to produce a composite silver nanopaste, which is rapidly cooled to solidify.
  • frictional heat forced heating is not necessary.
  • the composite silver nanoparticles are uniformly dispersed in the resin, and then the silver fine particles are uniformly dispersed. Therefore, the composite silver nanoparticles and the silver fine particles are dispersed independently, and uniform to eliminate the interaction between the two. It is characterized by further increasing dispersibility.
  • a paste intermediate is produced by mixing a predetermined weight% of silver fine particle Ag powder and a predetermined weight% of resin while heating.
  • a predetermined weight percent of composite silver nanoparticle CnAgAL powder is uniformly mixed with this paste intermediate while heating to produce a composite silver nanopaste, which is rapidly cooled to solidify.
  • frictional heat forced heating is not necessary.
  • the silver fine particles are first uniformly dispersed in the resin, and then the composite silver nanoparticles are uniformly dispersed. Therefore, the composite silver nanoparticles and the silver fine particles are independently dispersed to eliminate the interaction between the two. Uniform dispersibility is further increased.
  • Table 3 is an exemplary table of resins used in the present invention.
  • IBCH is a so-called rosin-like, has no fluidity at room temperature, and has a property of fluidizing rapidly by heating.
  • Glycerin is less viscous than ICBH and is in the form of a so-called syrup. Glycerin almost loses its fluidity when cooled to a refrigerator temperature or lower, and fluidizes when heated, so that it can be used as the resin of the present invention in the same manner as IBCH.
  • a substance that is solid at room temperature of 30 ° C. or lower has a property of being liquefied when heated to 40 ° C.
  • Table 4 is a relationship table between viscosity and temperature of IBCH. Since it is 150,000 centipoise (cP) at 30 ° C. or lower, it does not have fluidity, but when it is 40 ° C. or higher, particularly 50 ° C. or higher, fluidity is rapidly developed, and it is an optimal resin for the present invention.
  • cP centipoise
  • FIG. 9 is a characteristic diagram of viscosity and temperature of IBCH resin.
  • the relationship between the viscosity and the temperature shown in Table 4 is plotted, and it can be seen that the IBCH resin has a property of rapidly changing with respect to temperature as the viscosity is displayed on a logarithmic axis. All resins having such properties and having the property of being completely diffused by firing can be used in the present invention.
  • FIG. 10 is a thermal analysis diagram of IBCH resin with a temperature increase rate of 3 ° C./min. From DTA, the complete evaporation temperature is 205 ° C., and from TG, the weight is found to be 0% at 205 ° C., and it is proved that the entire amount has evaporated and disappeared.
  • Table 5 is a relationship table between the temperature rising rate of ICBH resin and the evaporation temperature.
  • a temperature increase rate of 3 (° C./min) means a program temperature increase in which the temperature is increased while increasing by 3 ° C. per minute.
  • the evaporation temperature decreases as the temperature increase rate decreases, and the evaporation temperature increases as the temperature increase rate increases.
  • the rate of temperature increase is set small, and the alcoholate group is diffused after the resin is completely evaporated.
  • the rate of temperature rise should be set large, and then the resin will completely evaporate.
  • a method in which alcoholate groups are diffused is employed.
  • FIG. 11 is a graph showing the relationship between the evaporation temperature of the IBCH resin and the temperature rise rate. The relationship between the evaporation temperature shown in Table 5 and the temperature increase rate is plotted. Based on this graph, the evaporation rate can be arbitrarily adjusted by adjusting the temperature increase rate.
  • Table 6 is a relationship table between viscosity and temperature of glycerin. At 0 ° C., it is 12100 centipoise (cP), and upon further cooling, the viscosity increases rapidly and facilitates a non-flowing state. On the other hand, when the temperature is set to 10 ° C. or higher, the viscosity becomes 3900 (cP) or lower and exhibits fluidity. While IBCH exhibits a slightly high temperature resin characteristic, glycerin is a resin that exhibits a low temperature resin characteristic, and by appropriately using both, non-fluidity / fluidity change can be realized. As described above, non-fluidity means non-aggregation of composite silver nanoparticles.
  • FIG. 12 is a characteristic diagram of viscosity and temperature of glycerin resin.
  • the relationship between the viscosity and the temperature shown in Table 6 is plotted, and it can be seen that the glycerin resin also has a property of rapidly changing with respect to temperature as the viscosity is displayed on the logarithmic axis. All resins having such properties and having the property of being completely diffused by firing can be used in the present invention.
  • Table 7 is a list of various composite silver nanopastes used in the joining test of the present invention.
  • the components of the composite silver nanopaste are composite silver nanoparticle CnAgAL, silver fine particle Ag, resin, and solvent, and the composite silver nanopaste to which the solvent is added is only P19.
  • the addition amount of each component is shown by weight% (wt%) and is 100 wt% in total.
  • the silver content of the silver core and silver fine particles of the composite silver nanoparticle is shown in the rightmost column, and the remaining amount (not shown) is an organic matter. That is, the content of the alcoholate group and the resin constituting the organic coating layer is shown.
  • the paste from P5 to P19 has a high composite silver nanoparticle weight of 35.7 to 83.3 (wt%), and as a result, the weight of silver fine particles is compared with 33.3 to 53.6 (wt%).
  • P12 and P17 do not contain silver fine particles, but are composed only of composite silver nanoparticles and a resin, and are accordingly expensive.
  • the results of the paste characteristics of this group show that when the silver content is 80% or less, the bonding area ratio with the substrate is relatively low, and the electrical conductivity and thermal conductivity are also reduced. I understood. Further, when the weight percentage of the composite silver nanoparticles is increased, many voids (bubble cavities) are generated in the fired silver film, and the electrical conductivity tends to be low (in contrast, the electrical resistivity is high).
  • the present inventors believe that at the present time, if the bonding area ratio S (%) is 70 (%) or more, it can be used for bonding. Of course, it is better that the bonding area ratio S (%) is higher than 70 (%), but as a criterion, S ⁇ 70 is not possible ( ⁇ ), 70 ⁇ S ⁇ 85 is possible ( ⁇ ), 85 ⁇ S ⁇ 90 is provided as good ( ⁇ ), and 90 ⁇ S is provided as excellent ( ⁇ ).
  • S ⁇ 70 is not possible ( ⁇
  • 70 ⁇ S ⁇ 85 is possible
  • 85 ⁇ S ⁇ 90 is provided as good
  • 90 ⁇ S is provided as excellent ( ⁇ ).
  • the following discussion is advanced aiming at a range of S ⁇ 85 ( ⁇ and ⁇ ).
  • the P20, P20-2, P21, P22, and P23 groups cleared all of the bonding area ratio, the number of voids, the VF test, and the ⁇ VF test.
  • the weight of the composite silver nanoparticles is 5 to 30 (wt%)
  • the weight of the silver fine particles is 60 to 90 (wt%)
  • the weight of the resin is 15 (wt%) or less. It has been found that the composite silver nanoparticles have the action of an adhesive of silver fine particles, and a small amount of 30 wt% or less is sufficient.
  • the resin is 15 wt% or less, and with this amount, the action of fixing the silver fine particles and the composite silver nanoparticles to each other is realized. If it is more than this, the organic content will increase and the silver content will be reduced.
  • a non-flowable paste (which may be referred to as a non-aggregating paste) was heated to 40 ° C. or more to be fluidized so that it could be applied to the specimen.
  • a non-flowable paste (which may be referred to as a non-aggregating paste) was heated to 40 ° C. or more to be fluidized so that it could be applied to the specimen.
  • a room temperature 30 ° C. or lower to fix the silver fine particles and the composite silver nanoparticles and prevent their aggregation.
  • Table 8 is a list of alcohols used as solvents.
  • the composite silver nanoparticles used in the present invention are alcoholate type composite silver nanoparticles of C10AgAL and C12AgAL, the organic coating layer surrounding the silver core is an alcoholate group, and when alcohol is used as a solvent, composite silver nanoparticles are used.
  • As the alcohol methanol, ethanol, butanol, hexanol, and octanol can be used.
  • organic solvents such as acetone, ether, benzene, ethyl acetate, terpineol, dihydroterpineol, butyl carbitol, cellosolve and the like can be used.
  • the addition of a solvent reduces the silver content and causes agglomeration of composite silver nanoparticles and silver fine particles when it is made into a fluid paste, so a non-fluid paste without a solvent during storage and storage. It is recommended to add a solvent just before coating. Even when the storage period is very short, there is a possibility of aggregation, and therefore the addition of a solvent immediately before coating is desired. Even when a solvent is added, the addition amount is preferably 10 wt% or less, and particularly preferably 5 wt% or less of the total amount.
  • Table 9 is a thermal analysis table of the composite silver nanopaste (P5).
  • the temperature increase rate (° C./min) was divided into four stages of 3, 10, 25, and 50, and in each case, the characteristic temperature in the air was derived from the thermal analysis of DTA ⁇ TG. Only when the rate of temperature increase was 3 (° C./min), thermal analysis was performed in nitrogen.
  • the characteristic temperature is a general term for the following T1, T2, and T3.
  • the decomposition start temperature T1 (° C.) is a temperature at which the paste starts an exothermic reaction, and is an oxidative decomposition start temperature of organic matter.
  • the decomposition temperature T2 (° C.) is the maximum peak temperature in the final stage of oxidative decomposition as the temperature rises.
  • the metallization temperature T3 (° C.) is a temperature at which the DTA becomes a constant value after passing the maximum peak, and is a temperature at which the entire amount of organic matter is diffused. As can be seen from Table 9, all characteristic temperatures tend to increase as the rate of temperature increase increases. In the thermal analysis in a nitrogen atmosphere (N2), the decomposition start temperature T1 and the decomposition temperature T2 do not appear clearly, but the final metallization temperature T3 can be measured. It is considered that a clear exothermic peak does not appear in DTA because organic substances are not oxidized in nitrogen and there is no exothermic reaction due to oxidative decomposition.
  • the alcoholate group constituting the organic coating layer separates and evaporates from the silver core and the resin also evaporates, a decrease in the weight of TG can be clearly detected, and the metallization temperature T3 can be considered as a temperature at which TG becomes a constant value. At this time, some dip is also observed in the DTA, which will be described later.
  • FIG. 13 is a thermal analysis diagram of the composite silver nanopaste (P5).
  • FIG. 13 is a graph of Table 9.
  • the horizontal axis represents characteristic temperatures T1, T2, and T3, and the vertical axis represents temperature.
  • T1, T2, and T3 are on the same straight line when the temperature increase rate is the same. There is a tendency for the temperature rise rate to move parallel to the straight line.
  • the thermal analysis in nitrogen has only one point of 3 (° C./min), but it is observed that the temperature is lower than the straight line in the case of 3 (° C./min). Since organic substances are diffused by evaporation in nitrogen, it is considered that the rate of air diffusion is faster than that of oxidative gas and T3 in nitrogen is smaller than T3 in air.
  • Table 10 is a relationship table between the types of composite silver nanopaste and the bonding area ratio.
  • Various pastes were applied to a glass substrate, and this was baked to form a silver film, and the bonding area ratio S (%) was derived from the back side of the glass substrate to complete Table 10.
  • Ag paste is a paste containing only silver fine particles, P16 high temperature 300 ° C. is fired in a furnace at 300 ° C., program temperature rise is 300 ° C. program temperature described later in FIG.
  • ArGas means firing in argon gas
  • DH + and DH ++ mean dihydroterpineol solvent addition, respectively.
  • FIG. 14 is a relationship diagram of the bonding area ratio S (%) of various nano pastes and the paste silver content (%).
  • FIG. 15 is a joint diagram of the nanopaste (P12) with the glass surface.
  • the paste silver content was 66.2% and the firing temperature was 300 ° C. in the air, but the 300 ° C. program firing of FIG. 14 described later was performed.
  • the bonded area ratio S of the silver film after firing was 33.9%.
  • the reason why the bonding area ratio is not possible is as follows. Judging from Table 7, the P12 paste does not contain any silver fine particles, the composite silver nanoparticles are 73.5 wt%, the resin is 26.5 wt% of the remaining amount, and the silver content is 66.2 wt%. is there.
  • the amount of organic matter is as extremely high as 33.8 wt%, and the entire silver film is made of composite silver nanoparticles.
  • FIG. 16 is a bonding diagram of the nano paste (P16) with the Cu surface.
  • the paste silver content is 90% and the firing temperature is 300 ° C. in air for 30 minutes, but no program firing is performed.
  • the bonding area ratio S of the silver film after firing was as extremely high as 95.4%.
  • the P16 paste contains 52 wt% of silver fine particles having a particle diameter of 0.4 ⁇ m, composite silver nanoparticles are 40 wt%, the silver content is 90 wt%, and the organic matter amount is 10 wt% as a result.
  • the amount of organic matter is small, the amount of gas generated is reduced, and the number of voids is rapidly reduced.
  • the composite silver nanoparticles are accumulated so as to fill the gaps between the silver fine particles to form a silver film, and as a result, the bonding area ratio is considered to be extremely high at 95.4%.
  • FIG. 17 is a joint diagram of nano paste (P19).
  • the paste silver content is 90% and the firing temperature is 300 ° C. in air for 30 minutes, but no program firing is performed.
  • the bonding area ratio S of the silver film after firing was as extremely high as 95.4%.
  • the reason why the bonding area ratio is excellent is as follows.
  • the P16 paste contains 52 wt% of silver fine particles having a particle size of 0.4 ⁇ m, composite silver nanoparticles are 40 wt%, the silver content is 87.4 wt%, and the organic matter amount is 10 wt% as a result.
  • FIG. 18 is a temperature / time relationship diagram in the paste.
  • FIG. 18 shows three types of temperature raising programs with the maximum temperatures of 300 ° C., 250 ° C., and 200 ° C., but the maximum temperature can be increased to 350 ° C., 400 ° C., 450 ° C., and 500 ° C.
  • the firing time can also be changed from 15 minutes and 20 minutes to 1 hour and 2 hours.
  • This firing temperature raising program can be realized by an electric furnace controlled by a computer. In the case of precise firing, it is preferable to use a computer-controlled temperature raising program.
  • Table 11 shows the relationship between the type of composite silver nanopaste, the bonding area ratio, and the specific resistance.
  • Three types of paste films of P12, P16, and P19 were applied to a glass plate having a width W (cm) and a length L (cm), and firing was performed for 15 minutes by a temperature rising program at 300 ° C. As a result, a silver film having a film thickness d ( ⁇ m) was formed.
  • the bonding area ratio S (%) between the silver film and the glass plate and the electrical resistivity ⁇ ( ⁇ cm) of the silver film were measured, and the results shown in Table 11 were obtained. When the electrical resistivity ⁇ ( ⁇ cm) was ⁇ ⁇ 10 ( ⁇ cm), good results were confirmed, and the pastes of P16 and P19 were accepted.
  • pastes P16 and P19 cleared the bonding area ratio and electrical resistivity tests. Furthermore, with respect to P16 and P19, a VF test and a ⁇ VF test on a diode test body described later were performed. Both P16 and P19 could not sufficiently clear the VF test and ⁇ VF test, which are semiconductor characteristic tests. However, it has been found that P16 and P19 can be sufficiently applied to the electrode pattern characteristics on the substrate.
  • the composite silver nanoparticles of P20 to P23 have a relatively small weight of 5 to 30 (wt%), the silver fine particles have a relatively large weight of 60 to 90 (wt%), but the silver content is 84 (Wt%) or more is set.
  • the composite silver nanoparticles of P16 and P19 have a weight of 30 (wt%) or more and the silver fine particles have a weight of 60 (wt%) or less, but the silver content is 85 (wt%) or more.
  • the pastes P20 to P23 are characterized in that the compounding ratio of the composite silver nanoparticles is decreased and the compounding ratio of the silver fine particles is increased accordingly.
  • the idea of the present inventors is that the composite silver nanoparticles may be small in that they play the role of an adhesive between the silver fine particles, and the contribution to the silver content rate is that the first is silver fine particles and the second is composite silver nanoparticles. In order.
  • the particle size of the silver fine particles used in the present invention is preferably 0.1 to 3.0 ⁇ m.
  • the average particle diameter of the silver nuclei of the composite silver nanoparticles is 1 to 20 nm.
  • the compounding ratio of the composite silver nanoparticles is sufficient to fill the gap.
  • the weight of the silver fine particles is 60 to 90 (wt%), whereas the weight described above is sufficient.
  • firing in nitrogen is advantageous for bonding.
  • organic substances are oxidized and decomposed, generating heat, and the generated heat causes silver nuclei to generate large thermal vibrations that are difficult to move into the gaps between the silver fine particles. Therefore, it was found that many voids were formed in the silver film. Void formation increases the electrical resistivity (lower electrical conductivity) and decreases thermal conductivity, which tends to adversely affect the semiconductor elements to be joined.
  • firing in air has a weak point in that the firing temperature is increased by an exothermic action.
  • the organic substance evaporates without being oxidatively decomposed, and the evaporation temperature is generally lower than the oxidative decomposition temperature. Therefore, there is an advantage that the firing temperature can be lower than the firing temperature in the air. Moreover, since it evaporates while absorbing heat, it has the effect of lowering the firing temperature. Therefore, at such a low firing temperature, the thermal vibration of the silver nuclei is small, and the silver nuclei move naturally into the gaps between the silver fine particles, so that the silver film can be densified. The densification of the silver film provides high electrical conductivity and high thermal conductivity, so that both the VF test and the ⁇ VF test described later can be cleared. Further, since the alcoholate group and the resin molecule evaporate as they are without being decomposed, the amount of generated gas is less than that of oxidative decomposition, and the amount of voids that are gas escape holes can be reduced.
  • FIG. 19 is a thermal analysis diagram of the nanopaste (P20-2) in air firing. Thermal analysis was performed by heating 16 mg of P20-2 paste from room temperature (RT) to 400 ° C. at a rate of temperature increase of 3 ° C./min.
  • the decomposition start temperature T1 was 158 ° C.
  • the maximum peak temperature decomposition temperature T2 was 237 ° C.
  • the metallization temperature T3 was 249 ° C.
  • TG has a constriction at 175 ° C.
  • the temperature at which the TG actually becomes a constant value is the same temperature as T3 (237 ° C.).
  • FIG. 20 is a thermal analysis diagram of baking of the nanopaste (P20-2) in nitrogen.
  • Thermal analysis was performed by heating 15 mg of P20-2 paste from room temperature (RT) to 400 ° C. at a rate of temperature increase of 3 ° C./min.
  • RT room temperature
  • T1 and T2 were not clear
  • the metallization temperature T3 was 173 ° C.
  • From TG, 173 ° C. is obtained as T3.
  • 19 and 20 were compared, it was found that the metallization temperature was 173 ° C. for firing in nitrogen and 249 ° C. for firing in air, and the temperature in nitrogen was considerably low.
  • the firing temperature can be set low in nitrogen, it is effective in reducing costs. Further, if the firing temperature in nitrogen is set to be as high as the firing temperature in air, the density of the produced silver film can be further improved, and high electrical conduction and high thermal conduction can be guaranteed.
  • FIG. 21 is a thermal analysis diagram of the nanopaste (P21) in air firing. Thermal analysis was performed by heating 15 mg of P21 paste from room temperature (RT) to 400 ° C. at a rate of temperature increase of 3 ° C./min.
  • the decomposition start temperature T1 was 152 ° C.
  • the maximum peak temperature decomposition temperature T2 was 253 ° C.
  • the metallization temperature T3 was 277 ° C.
  • TG has a constriction at 158 ° C., the temperature actually decreased slowly, and the temperature at which it reached a constant value was the same temperature as T3 (277 ° C.).
  • FIG. 22 is a thermal analysis diagram in the firing of the nanopaste (P21) in nitrogen. Thermal analysis was performed by heating 16 mg of P21 paste from room temperature (RT) to 400 ° C. at a rate of temperature increase of 3 ° C./min. In DTA, no exothermic peak was observed, decomposition start temperature T1 and decomposition temperature T2 were not clear, and metallization temperature T3 was 176 ° C. From TG, 176 ° C. is obtained as T3.
  • RT room temperature
  • metallization temperature T3 was 176 ° C. From TG, 176 ° C. is obtained as T3.
  • FIG. 21 and FIG. 22 are compared, it was found that the metallization temperature was 177 ° C. for firing in nitrogen and 277 ° C. for firing in air, and the temperature in nitrogen was considerably low.
  • the firing temperature can be set low in nitrogen, it is effective in reducing costs. It was also demonstrated that if the firing temperature in nitrogen is set as high as the firing temperature in air, the density of the resulting silver film can be further improved and high electrical conductivity and high thermal conductivity can be guaranteed.
  • FIG. 23 is a thermal analysis diagram of the nanopaste (P22) in air firing. Thermal analysis was performed by heating 15 mg of P22 paste from room temperature (RT) to 400 ° C. at a rate of temperature increase of 1 ° C./min.
  • the decomposition start temperature T1 was 128 ° C.
  • the maximum peak temperature decomposition temperature T2 was 220 ° C.
  • the metallization temperature T3 was 258 ° C.
  • TG has a constriction at 143 ° C., it actually decreased slowly, and the temperature at which it reached a constant value was 236 ° C., which was slightly lower than T3.
  • FIG. 24 is a thermal analysis diagram in baking of the nanopaste (P22) in nitrogen. Thermal analysis was performed by heating 15 mg of P22 paste from room temperature (RT) to 400 ° C. at a rate of temperature increase of 1 ° C./min. DTA was not shown, and the metallization temperature T3 from the TG was 152 ° C. In the air-fired TG shown together in the figure, it can be seen that the TG decreases from 152 ° C. to 230 ° C. That is, even if metallized in nitrogen, air diffusion still continues in the air, and it is necessary to raise the temperature by about 80 ° C. for metallization. Comparing FIG. 23 and FIG. 24, it was found that the metallization temperature was 177 ° C.
  • the firing temperature in nitrogen was considerably low. That is, the firing temperature can be set low in nitrogen. It was also demonstrated that if the firing temperature in nitrogen is set as high as the firing temperature in air, the density of the resulting silver film can be further improved and high electrical conductivity and high thermal conductivity can be guaranteed.
  • FIG. 25 is a thermal analysis diagram of the nanopaste (P23) in air firing. Thermal analysis was performed by heating 14 mg of P23 paste from room temperature (RT) to 400 ° C. at a rate of temperature increase of 3 ° C./min.
  • the decomposition start temperature T1 was 130 ° C.
  • the maximum peak temperature decomposition temperature T2 was 238 ° C.
  • the metallization temperature T3 was 267 ° C.
  • TG has a constriction at 158 ° C., but actually it slowly decreased, and the temperature at which it reached a constant value was the same temperature as T3 (267 ° C.).
  • FIG. 26 is a thermal analysis diagram in the firing of the nanopaste (P23) in nitrogen. Thermal analysis was performed by heating 14 mg of P23 paste from room temperature (RT) to 400 ° C. at a rate of temperature increase of 3 ° C./min. In DTA, no exothermic peak was observed, the decomposition start temperature T1 and the decomposition temperature T2 were not clear, and the metallization temperature T3 was 170 ° C. Also from TG, 170 ° C. is obtained as T3. 25 and 26 were compared, it was found that the metallization temperature was 170 ° C. for firing in nitrogen and 267 ° C. for firing in air, and the temperature in nitrogen was considerably low.
  • the firing temperature can be set low in nitrogen, it is effective in reducing costs. It was also demonstrated that if the firing temperature in nitrogen is set as high as the firing temperature in air, the density of the resulting silver film can be further improved and high electrical conductivity and high thermal conductivity can be guaranteed.
  • FIG. 27 is a comparison diagram of TG thermal analysis when nanopastes (P20-2, P21, P23) are fired in nitrogen and in air. It can be seen that even if the TG reaches a certain value in the firing in nitrogen, the TG still continues to decrease in the firing in the air. Clearly, it has been demonstrated that the metallization temperature T3 is lower in the firing in nitrogen than in the air.
  • Table 12 is a characteristic temperature table in air and nitrogen of P20-2, P21, P22, and P23.
  • the characteristic temperatures (T1, T2, T3) measured in FIGS. 19 to 27 are listed. Only P22 has a temperature increase rate of 1 ° C./min, but the temperature increase rate of other pastes is 3 ° C./min. It is clear that the metallization temperature T3 for firing in nitrogen is considerably lower than the metallization temperature T3 for firing in air. However, the fact that the metallization temperature T3 for firing in nitrogen is obtained from TG, the fact that it is lower in nitrogen is clear.
  • FIG. 28 is a production process diagram of a diode resin mold for a bonding test.
  • the composite silver nanopaste layers 6 and 12 are applied onto the lead frames 2 and 4, respectively.
  • the diode chip 8 is placed on the composite silver nanopaste layer 6, and the composite silver nanopaste layer 10 is applied on the diode chip 8. Finally, both ends of the connection terminal 14 are placed on the composite silver nanopaste layers 10 and 12 to complete the diode assembly 1.
  • the diode assembly 1 is fired in the electric furnace 16, and the composite silver nanopaste layers 6, 10, 12 are changed to silver conductor layers 6a, 10a, 12a.
  • the fired diode assembly 1 is sealed with a resin mold 20 to complete a diode resin mold body 18, and the diode resin mold body 18 is transferred to a VF test and a ⁇ VF test described later.
  • the lead frames protruding from the left and right serve as an anode 22 and a cathode 24 as electrodes.
  • FIG. 29 is a joint test measurement diagram of VF and ⁇ VF of the diode resin mold body.
  • a DC power supply 26 is connected in series with an ammeter 28 between the anode 22 and the cathode 24, and a DC voltage is applied variably.
  • (29B) is an explanatory diagram of the VF test. The forward voltage VF through which the rated current IO flows is measured. It can be seen that the smaller the forward voltage VF is, the smaller the electrical resistance of the joint surface is, and thus a better joined state.
  • (29C) is an explanatory diagram of the ⁇ VF test.
  • a ⁇ VF test is performed. First, a forward current VF is measured by passing a minute current, and then a predetermined large current is passed for a certain time, and the forward voltage VF immediately after that is measured. When the difference ⁇ VF (millivolt) is small, heat is efficiently conducted through the joint surface, indicating that the joint state is good. That is, the electrical conductivity is measured by the VF test, and the thermal conductivity is measured by the ⁇ VF test.
  • FIG. 30 is a comparative diagram of VF when various pastes are fired in air and nitrogen.
  • a diode resin mold body shown in FIG. 29 was prepared from four types of P20, P21, P22, and P23 as composite silver nanopaste, and a VF test was performed.
  • Pb-5Sn which is a high-temperature solder that has been conventionally used.
  • FIG. 30 to FIG. 35 all the firing test results using Pb-5Sn are data obtained under a nitrogen atmosphere, and in order to clarify this, FIG. 30 to FIG. in N2). Firing in the air (firing in the air) was performed in a box furnace, and a reflow furnace was used for firing in nitrogen.
  • Pb-5Sn is only fired in nitrogen, and if the measured value of other pastes is small compared to the measured value of Pb-5Sn, the paste of the present invention is superior to the conventional high-temperature solder ( ⁇ ). It is determined that it is acceptable ( ⁇ ) if it is approximately the same, and is impossible ( ⁇ ) if it is large. In the case of firing in nitrogen, four types of pastes were ⁇ , and in the case of firing in air, P20 was x, but the remaining three types were ⁇ .
  • FIG. 31 is a comparative diagram of ⁇ VF in the firing of various pastes in air and nitrogen.
  • the four types of diode resin molds P20, P21, P22, and P23 used in FIG. 30 were used, and the ⁇ VF test was performed.
  • a diode resin mold using Pb-5Sn of FIG. 30 was also tested.
  • firing in air (firing in air) was performed in a box furnace, and reflow furnace was used for firing in nitrogen.
  • Pb-5Sn is only fired in nitrogen. If the measured value of other pastes is small compared to the measured value of Pb-5Sn, the paste of the present invention is judged to be superior to the conventional high-temperature solder ( ⁇ ).
  • Table 13 is a comparison table of the paste of the present invention and conventional Pb-5Sn solder for VF and ⁇ VF. This table is a summary of the results obtained in FIGS. In the firing in nitrogen, all pastes of P20 to P23 showed good ( ⁇ ) in comparison with Pb-5Sn in the VF test and ⁇ VF test, and all pastes were good ( ⁇ ) as a comprehensive judgment. On the other hand, in the air baking, none of the pastes obtained ⁇ , and the paste of the present invention failed.
  • FIG. 32 is a comparison diagram of VF after the initial reflow heat test in the firing of various pastes in the air.
  • a diode resin mold body obtained by firing the above-described four kinds of composite silver nanopastes P20, P21, P22, and P23 in the atmosphere was used.
  • a diode resin mold body obtained by firing Pb-5Sn in nitrogen was used.
  • the VF test was performed at the initial stage and after the reflow heat test, and compared with each other.
  • the reflow heat resistance test is a program temperature rise test method performed using a reflow furnace, and a normal temperature (room temperature) -260 ° C.-normal temperature (room temperature) thermal cycle (5 to 15 minutes, average temperature increase rate is 25 ° C. / Min) is a test method for measuring VF and ⁇ VF by performing three cycles.
  • the temperature increase rate is set to 3 ° C./min, but the average temperature increase rate in the actual reflow furnace is set to a considerably large value of 25 ° C./min.
  • the reason is to accurately measure the metallization temperature T3 in the air and nitrogen in the thermal analysis. If the measured value of the other paste is small compared to the measured value of Pb-5Sn, it is judged that the paste of the present invention is superior to the conventional high-temperature solder ( ⁇ ). It is judged as impossible ( ⁇ ). In the initial test, only P23 was ( ⁇ ) and the remaining three were ( ⁇ ). After the reflow heat test, all the pastes are (x).
  • FIG. 33 is a comparative view of ⁇ VF after the initial and reflow heat test in the firing of various pastes in the air.
  • a diode resin mold body obtained by firing the above-described four kinds of composite silver nanopastes P20, P21, P22, and P23 in the atmosphere was used.
  • a diode resin mold body obtained by firing Pb-5Sn in the air was used.
  • the ⁇ VF test was performed at the initial stage and after the reflow heat test, and compared with each other. Compared with the measured value of Pb-5Sn, P22 paste is ( ⁇ ) in the initial test, and all other pastes are ( ⁇ ). After the reflow heat test, all four types of pastes were (x).
  • Table 14 is a comparison table of the paste of the present invention and conventional Pb-5Sn solder for VF and ⁇ VF. This table summarizes the results obtained in FIGS. 32 and 33.
  • VF value P23 was ( ⁇ ) in the initial test, but the other paste was ( ⁇ ), and after the reflow heat test, all pastes were ( ⁇ ).
  • ⁇ VF value P22 was ( ⁇ ) in the initial test, but the other paste was ( ⁇ ), and after the reflow heat test, all pastes were ( ⁇ ). Therefore, in the atmospheric comprehensive judgment, all four types of pastes were rejected.
  • FIG. 34 is a comparison diagram of VF after the initial reflow heat test in firing various pastes in nitrogen.
  • a diode resin mold body obtained by firing the above-described four kinds of composite silver nanopastes P20, P21, P22, and P23 in nitrogen was used.
  • a diode resin mold body obtained by firing Pb-5Sn in nitrogen was used.
  • the VF test was performed at the initial stage and after the reflow heat test, and compared with each other. Compared with the measured value of Pb-5Sn, all the four types of pastes showed ( ⁇ ) in the measurement at the initial stage and after the reflow heat test.
  • FIG. 35 is a comparative view of ⁇ VF after the initial and reflow heat test in firing various pastes in nitrogen.
  • a diode resin mold body obtained by firing the above-described four kinds of composite silver nanopastes P20, P21, P22, and P23 in nitrogen was used.
  • a diode resin mold body obtained by firing Pb-5Sn in nitrogen was used.
  • the ⁇ VF test was performed at the initial stage and after the reflow heat resistance test and compared with each other. Compared with the measured value of Pb-5Sn, all four types of pastes showed ( ⁇ ) in the measurement after the initial test and the reflow heat resistance test.
  • Table 15 is a comparison table of the paste of the present invention and conventional Pb-5Sn solder for VF and ⁇ VF. This table summarizes the results obtained in FIGS. 34 and 35. Regarding the VF value and ⁇ VF value, all pastes were ( ⁇ ) after the initial stage and after the reflow heat test.
  • an organic coating layer composed of at least one alcohol molecule residue, alcohol molecule derivative and / or alcohol molecule having 10 or 12 carbon atoms is formed around a silver nucleus composed of an aggregate of silver atoms.
  • the composite silver nanoparticles, the silver fine particles, and the resin are uniformly mixed, and the resin is in a solid or high-viscosity non-flowing state at 30 ° C. or less, and the composite silver nanoparticles and the silver fine particles are uniformly mixed.
  • a composite silver nanopaste that is kept in a dispersed state and fluidized by heating to enable coating.
  • a paste that prevents aggregation of composite silver nanoparticles by non-fluidity and develops coating performance by heat fluidity is provided.
  • the composite silver nanopaste of the present invention has a structure such as an electronic material such as a printed wiring / conductive material, a magnetic material such as a magnetic recording medium / electromagnetic wave absorber / electromagnetic resonator, a far infrared material / composite film forming material, etc. It can be applied to pastes in various fields such as materials, ceramics and metal materials such as sintering aids and coating materials, and medical materials.

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Abstract

This invention provides a technique for pasting composite silver nanoparticles of C10 or C12 in such a state that is not aggregated, that is, a nonaggregative paste. The composite silver nanopaste is characterized in that composite silver nanoparticles comprising an organic covering layer, formed of at least one of alcohol molecule residues having 10 or 12 carbon atoms, alcohol molecule derivatives and/or alcohol molecules, provided around silver nuclei formed of aggregates of silver atoms, fine particles of silver, and a resin are homogeneously mixed together to constitute the composite silver nanopaste, and the resin can hold the composite silver nanoparticles and the fine particles of silver in a homogeneously dispersed state in a solid or highly viscous nonfluid state at 30ºC or below while, upon heating, the resin becomes flowable and coatable. Preferably, the average particle diameter of the silver nuclei is 1 to 20 nm, the average particle diameter of the fine particles of silver is 0.1 to 3.0 μm, the weight of the composite silver nanoparticles is 5 to 30 (wt%), the weight of the fine particles of silver is 60 to 90 (wt%), and the weight of the resin is not more than 15 (wt%).

Description

複合銀ナノペースト、その製法及びナノペースト接合方法Composite silver nanopaste, its production method and nanopaste bonding method
　本発明は、多数の銀原子からなる銀核の周囲に有機物からなる有機被覆層を形成した複合銀ナノ粒子を成分とするペーストに関し、更に詳細には、前記ペーストを塗着して焼成することにより前記有機被覆層や他の有機成分を気散させて銀膜を形成し、この銀膜により半導体接合や電極パターンを形成する複合銀ナノペースト、その製法及びナノペースト接合方法に関する。 The present invention relates to a paste composed of composite silver nanoparticles in which an organic coating layer made of an organic substance is formed around a silver nucleus made of a large number of silver atoms. More specifically, the paste is applied and fired. The present invention relates to a composite silver nanopaste in which the organic coating layer and other organic components are diffused to form a silver film, and a semiconductor bond and an electrode pattern are formed by the silver film, a method for manufacturing the same, and a nanopaste bonding method.
　一般に、半導体、電子回路、電子機器などは各種の電子部品を基板に半田で溶融固定して電気的導通性を確保している。しかし、従来の半田はＳｎとＰｂの合金であり、近年の環境保全対策としてＰｂの使用が禁止されつつあるため、前記従来半田に替わるＰｂフリーの代替半田の開発が要望されている。 Generally, in semiconductors, electronic circuits, electronic devices, etc., various electronic components are fused and fixed to a substrate with solder to ensure electrical continuity. However, the conventional solder is an alloy of Sn and Pb, and the use of Pb is being prohibited as a recent environmental preservation measure. Therefore, development of a Pb-free alternative solder that replaces the conventional solder is desired.
　代替半田の特性として、Ｐｂを含有しないことは当然であるが、その他に熱伝導性が高く、融点が低く、電気伝導度が高くしかも安全性が高いことが要望されている。この期待に応える素材として銀が注目され、超微粒子として複合銀ナノ粒子が開発されるに到った。 As a characteristic of the alternative solder, it is natural that Pb is not contained, but there are other demands for high thermal conductivity, low melting point, high electrical conductivity and high safety. Silver has attracted attention as a material that meets this expectation, and composite silver nanoparticles have been developed as ultrafine particles.
　まず、特許文献１として特許第３２０５７９３号公報が公開された。出発物質として銀有機化合物（特に銀有機錯体）が選択された。空気を遮断した不活性ガス雰囲気下で、前記銀有機化合物を分解開始温度以上で、且つ完全分解温度未満の温度で加熱し、分解還元された銀核の周囲に前記銀有機化合物の被覆層を有した複合銀ナノ粒子が製造された。銀核の粒径は１～１００ｎｍであり、そのため通称で複合銀ナノ粒子と称される。具体的には、ステアリン酸銀１００ｇを窒素気流下のフラスコ内で２５０℃で４時間加熱すると、粒径５ｎｍの銀核を有する複合銀ナノ粒子が生成された。 First, Japanese Patent No. 3205793 was published as Patent Document 1. Silver organic compounds (especially silver organic complexes) were selected as starting materials. The silver organic compound is heated at a temperature higher than or equal to the decomposition start temperature and lower than the complete decomposition temperature in an inert gas atmosphere in which air is shut off, and the coating layer of the silver organic compound is formed around the decomposed and reduced silver core. Composite silver nanoparticles were produced. The particle size of silver nuclei is 1 to 100 nm, and is therefore commonly referred to as composite silver nanoparticles. Specifically, when 100 g of silver stearate was heated at 250 ° C. for 4 hours in a flask under a nitrogen stream, composite silver nanoparticles having a silver nucleus with a particle size of 5 nm were generated.
　前記製法では、ステアリン酸銀を溶媒無しの固相法で加熱するため、生成された複合銀ナノ粒子の銀核がたとえ５ｎｍであっても、多数の複合銀ナノ粒子が団子状態に結合して大きな２次粒子になる欠点がある。しかもステアリン酸銀を出発物質とするため、銀核の周囲に炭素数１７のステアリン酸基が有機被覆層となり、銀含有率が小さくなる欠点を有していた。 In the manufacturing method, since silver stearate is heated by a solid phase method without a solvent, even if the silver nuclei of the generated composite silver nanoparticles are 5 nm, a large number of composite silver nanoparticles are bound in a dumpling state. There is a drawback of becoming large secondary particles. In addition, since silver stearate is used as a starting material, a stearic acid group having 17 carbon atoms around the silver core becomes an organic coating layer, which has the disadvantage that the silver content is reduced.
　そこで、特許文献２としてＷＯ００／０７６６９９号公報が公開された。本発明者はこの国際公開公報の発明者の一人である。この公開公報には複数の発明が開示されているが、その中でも金属無機化合物を界面活性剤を用いて処理する方法が重要である。即ち、金属無機化合物を界面活性剤を用いて非水系溶媒中でコロイド化して超微粒子前駆体を形成する第１工程と、このコロイド溶液中に還元剤を添加して前記超微粒子前駆体を還元し、金属核の外周に界面活性剤殻を被覆層として形成した複合金属ナノ粒子を生成する第２工程から構成される。 Therefore, WO 00/076699 was published as Patent Document 2. The inventor is one of the inventors of this international publication. A plurality of inventions are disclosed in this publication, and among them, a method of treating a metal inorganic compound with a surfactant is important. That is, a first step of colloiding a metal inorganic compound with a surfactant in a non-aqueous solvent to form an ultrafine particle precursor, and a reducing agent is added to the colloidal solution to reduce the ultrafine particle precursor. And a second step of generating composite metal nanoparticles in which a surfactant shell is formed as a coating layer on the outer periphery of the metal core.
　前記方法は、非水系溶媒に金属無機化合物を溶解させるから、生成した複合金属ナノ粒子同士が非水系溶媒中に分散し、団子状態になり難い特徴を有している。しかし、添加した界面活性剤は炭素数が大きいため、有機被覆層である界面活性剤殻の炭素数は当然大きく、界面活性剤殻を焼成して気散させる温度、即ち焼成温度が高くなる欠点があった。 The above-described method has a feature that since the metal inorganic compound is dissolved in a non-aqueous solvent, the produced composite metal nanoparticles are dispersed in the non-aqueous solvent and are not likely to be in a dumpling state. However, since the added surfactant has a large number of carbon atoms, the number of carbon atoms in the surfactant shell, which is an organic coating layer, is naturally large, and the temperature at which the surfactant shell is baked to disperse, that is, the firing temperature is increased. was there.
　このような中で、複合銀ナノ粒子の研究が進展し、特許文献３としてＷＯ０１／０７０４３５号公報が公開された。この公開公報中で、炭酸銀とミリスチン酸（Ｃ数は１４）から複合銀ナノ粒子ができたと記載されている。また、炭酸銀とステアリルアルコール（Ｃ数は１８）から複合銀ナノ粒子が生成されたことが記載されている。しかし、ミリスチン酸（Ｃ数は１４）もステアリルアルコール（Ｃ数は１８）も炭素数が大きいため、銀化させるための焼成温度が高くなる欠点があることは云うまでもない。 Under such circumstances, research on composite silver nanoparticles has progressed, and WO 01/070435 has been published as Patent Document 3. In this publication, it is described that composite silver nanoparticles are made from silver carbonate and myristic acid (C number is 14). Further, it is described that composite silver nanoparticles were produced from silver carbonate and stearyl alcohol (C number is 18). However, since myristic acid (C number is 14) and stearyl alcohol (C number is 18) have a large carbon number, it goes without saying that there is a disadvantage that the firing temperature for silvering becomes high.
特許第３２０５７９３号公報Japanese Patent No. 3205793 ＷＯ００／０７６６９９号公報WO00 / 076699 ＷＯ０１／０７０４３５号公報WO01 / 070435 特許第３６３８４８６号公報Japanese Patent No. 3638486 特許第３６３８４８７号公報Japanese Patent No. 3638487
　本発明者等は、銀化温度を低下させるために、炭酸銀とデカノール（Ｃ数１０のアルコール）を反応させて、銀核の周囲にデカノール残基からなる銀アルコラート型複合銀ナノ粒子を生成することに成功した。同様に、炭酸銀とドデカノール（Ｃ数１２のアルコール）を反応させて、銀核の周囲にドデカノール残基からなる銀アルコラート型複合銀ナノ粒子を生成することにも成功した。 In order to lower the silvering temperature, the present inventors reacted silver carbonate and decanol (C number 10 alcohol) to produce silver alcoholate-type composite silver nanoparticles composed of decanol residues around the silver nucleus. Succeeded in doing. Similarly, silver carbonate and dodecanol (C12 alcohol) were reacted to successfully produce silver alcoholate-type composite silver nanoparticles composed of dodecanol residues around the silver core.
　このようにして得られたＣ数１０の複合銀ナノ粒子及びＣ数１２の複合銀ナノ粒子は、特許文献３で得られたＣ数１４又はＣ数１８の複合銀ナノ粒子よりも、銀化温度が低くなることは当然である。炭素数が小さくなる結果、銀化温度が低下すると同時に、銀含有率が増大する利点がある。 The C number 10 composite silver nanoparticles and the C number 12 composite silver nanoparticles obtained in this way are more silverated than the C number 14 or C number 18 composite silver nanoparticles obtained in Patent Document 3. It goes without saying that the temperature is lowered. As a result of the decrease in the number of carbon atoms, there is an advantage that the silver content increases while the silvering temperature decreases.
　そこで、本発明者等は、前記Ｃ数１０の複合銀ナノ粒子を用いてペーストを作製することにした。同様に、前記Ｃ数１２の複合銀ナノ粒子を用いてペーストを作製する。このペーストを用いて、半導体を基板上に固定する試験を行い、ペーストの有効性を確認する。ペーストを用いた接合方法については、下記の２件の特許公報が存在する。 Therefore, the present inventors decided to produce a paste using the C number 10 composite silver nanoparticles. Similarly, a paste is prepared using the C number 12 composite silver nanoparticles. Using this paste, a test for fixing the semiconductor on the substrate is performed to confirm the effectiveness of the paste. Regarding the bonding method using paste, there are the following two patent publications.
　特許文献４として、特許第３６３８４８６号公報が公開されている。ここには、平均粒径が１～１０ｎｍの実質的に金属成分からなるコア部の周囲を、炭素数が５以上の有機物からなる被覆層で被覆した複合金属超微粒子を予め作製し、該複合金属超微粒子を溶媒に分散させて金属ペーストを調整する工程と、該金属ペーストを回路基板の端子電極上に付着させて主に複合金属超微粒子からなる金属ペーストボールを形成する工程と、該金属ペーストボール上にフェイスダウン法を用いて半導体素子の電極を接合する工程と、低温焼成により半導体素子と回路基板とを電気的に接続する工程が記載されている。 Japanese Patent No. 3638486 is disclosed as Patent Document 4. Here, composite metal ultrafine particles in which the periphery of a core portion substantially composed of a metal component having an average particle diameter of 1 to 10 nm is coated with a coating layer composed of an organic substance having 5 or more carbon atoms are prepared in advance, and the composite Preparing a metal paste by dispersing metal ultrafine particles in a solvent, attaching the metal paste onto a terminal electrode of a circuit board to form a metal paste ball mainly composed of composite metal ultrafine particles, and the metal There are described a step of bonding electrodes of a semiconductor element on a paste ball using a face-down method and a step of electrically connecting the semiconductor element and a circuit board by low-temperature firing.
　また、特許文献５として、特許第３６３８４８７号公報が公開されている。この特許公報には、平均粒径が１～１０ｎｍの実質的に金属成分からなるコア部の周囲を、炭素数が５以上の有機物からなる被覆層で被覆した複合金属超微粒子を予め作製し、該複合金属超微粒子を溶媒に分散させて金属ペーストを調整する工程と、該金属ペーストを半導体素子の電極上に付着させ低温焼成して超微粒子電極を作製する工程と、該超微粒子電極上にはんだバンプを形成する工程と、該はんだバンプを回路基板の端子電極に加熱融着する工程が開示されている。 Also, as patent document 5, Japanese Patent No. 3638487 is disclosed. In this patent publication, composite metal ultrafine particles in which the periphery of a core portion substantially composed of a metal component having an average particle diameter of 1 to 10 nm is coated with a coating layer composed of an organic substance having 5 or more carbon atoms are prepared in advance. A step of preparing a metal paste by dispersing the composite metal ultrafine particles in a solvent, a step of depositing the metal paste on an electrode of a semiconductor element and firing at a low temperature to produce an ultrafine particle electrode, A process of forming a solder bump and a process of heat-sealing the solder bump to a terminal electrode of a circuit board are disclosed.
　前記特許文献４、５には、複合金属超微粒子を溶媒に分散させて金属ペーストを調整することが記載され、特に特許文献４の請求項３には、導電率が高い金属と樹脂分が添加される金属ペーストが記載されている。両文献には、溶媒としてトルエンのみが例示されており、特許文献４、５の溶媒とは粘性を低下させてペーストを溶液状にする役割が付与されている。前記樹脂分は粘性を増加させるために添加されるものであり、溶媒と樹脂分を適当量添加して所定粘性のペーストが作製されることになる。 Patent Documents 4 and 5 describe that a metal paste is prepared by dispersing composite metal ultrafine particles in a solvent. In particular, claim 3 of Patent Document 4 includes a metal having a high conductivity and a resin component. A metal paste is described. In both documents, only toluene is exemplified as a solvent, and the roles of Patent Documents 4 and 5 are imparted with a role of reducing the viscosity to make the paste into a solution. The resin component is added to increase the viscosity, and an appropriate amount of solvent and resin component is added to produce a paste having a predetermined viscosity.
　前記特許文献４及び５に従って、本発明者等も、前述したＣ１０の複合銀ナノ粒子をトルエンに溶解させてＣ１０ペーストを作製し、同様にＣ１２の複合銀ナノ粒子をトルエンに溶解させてＣ１２ペーストを作製した。両ペーストは、基板や半導体電極に塗着し易いように、室温で傾斜させたときに自然に流下する程度の粘性に調製された。両ペーストは、２週間だけ室温下で容器内に保管された。２週間の保管後、回路基板に膜厚１μｍのペースト膜をスクリーン印刷法で形成し、電気炉内で３５０℃・２０分間の焼成を行って、ペースト膜から銀膜に成形した。 According to Patent Documents 4 and 5, the present inventors also prepared C10 paste by dissolving the above-described C10 composite silver nanoparticles in toluene, and similarly dissolved C12 composite silver nanoparticles in toluene to obtain C12 paste. Was made. Both pastes were prepared to have such a viscosity that they would flow naturally when tilted at room temperature so that they could be easily applied to a substrate or a semiconductor electrode. Both pastes were stored in containers at room temperature for only 2 weeks. After storage for 2 weeks, a paste film having a thickness of 1 μm was formed on the circuit board by screen printing, and baked in an electric furnace at 350 ° C. for 20 minutes to form the paste film into a silver film.
　光学顕微鏡と電子顕微鏡を用いて、前記銀膜の表面及び断面が観察された。その結果、銀膜表面に多少の凹凸が発見された。３５０℃の焼成では、有機物は全て気散するが、銀核は溶融せず、表面融解して銀核同士が焼結して銀膜が形成される。従って、銀核が大きければ、表面の凹凸は増幅されることになる。つまり、前記表面の凹凸は、大きな銀核同士の焼結により形成されたものと考えられた。大きな銀核が形成された理由は、２週間の保管中に、ペースト内で複合銀ナノ粒子が相互に凝集して２次粒子化して団子粒子が形成された結果だと考えられる。凝集を防止するために、分散剤や界面活性剤をペーストに添加すると、ペースト中の銀含有率が低下し、また界面活性剤は３５０℃では完全に気散せず、銀膜中に有機物が残留する事態もある。従って、ペーストには余分な有機物を添加することは、低温焼成を視野におく限り、極力避けることが必要である。 The surface and cross section of the silver film were observed using an optical microscope and an electron microscope. As a result, some irregularities were found on the surface of the silver film. In the baking at 350 ° C., all organic substances are diffused, but the silver nuclei are not melted, but the surface is melted and the silver nuclei are sintered to form a silver film. Therefore, if the silver nuclei are large, the surface irregularities will be amplified. That is, it was considered that the unevenness on the surface was formed by sintering between large silver nuclei. The reason for the formation of large silver nuclei is considered to be the result of composite silver nanoparticles agglomerating with each other in the paste to form secondary particles during storage for 2 weeks. When a dispersant or a surfactant is added to the paste to prevent agglomeration, the silver content in the paste decreases, and the surfactant does not completely dissipate at 350 ° C., and organic substances are not present in the silver film. There is also a situation that remains. Therefore, it is necessary to avoid adding extra organic matter to the paste as much as possible as long as low temperature firing is considered.
　複合銀ナノ粒子が溶媒添加前に凝集していた可能性もあり、複合銀ナノ粒子を事前に乳鉢で微細に磨り潰して単分散化し、その後に溶媒を添加してペーストを作製した。このペーストを用いて回路基板上にペースト膜を形成し、３５０℃で２０分間の焼成を行った。電子顕微鏡で観察したところ、銀膜の表面の凹凸は多少改善されていたが、まだ凹凸が残留していた。 The composite silver nanoparticles may have aggregated before the addition of the solvent, and the composite silver nanoparticles were finely ground and monodispersed in advance in a mortar, and then the solvent was added to prepare a paste. A paste film was formed on the circuit board using this paste, and baked at 350 ° C. for 20 minutes. When observed with an electron microscope, the irregularities on the surface of the silver film were somewhat improved, but the irregularities still remained.
　以上の結果から、複合銀ナノ粒子を溶媒と混合して流動状態で保管すると、複合銀ナノ粒子同士の凝集が生起して２次粒子化し、保管時間が長くなるに従って、２次粒子の粒径が増加するという結論が得られた。この結果は、複合銀ナノ粒子をトルエン等の粘性の小さな溶媒に添加して、室温で流動性を有した流動性ペーストを事前に量産しておくことの問題点を浮き彫りにした。 From the above results, when the composite silver nanoparticles are mixed with a solvent and stored in a fluidized state, the composite silver nanoparticles agglomerate into secondary particles, and the particle size of the secondary particles increases as the storage time increases. The conclusion is reached that increases. This result highlights the problem of adding composite silver nanoparticles to a low viscosity solvent such as toluene and mass producing a fluid paste that has fluidity at room temperature in advance.
　従って、本発明の目的は、Ｃ１０又はＣ１２の複合銀ナノ粒子を凝集しない形態でペースト化する技術、つまり非凝集性ペーストを提供し、その非凝集性を非流動性により実現した非流動性ペースを提供することである。また、その非流動性ペーストの製造方法を提供し、同時に非流動性ペーストを利用した接合方法を提供することである。 Accordingly, an object of the present invention is to provide a technology for pasting C10 or C12 composite silver nanoparticles in a form that does not aggregate, that is, a non-aggregating paste, and a non-fluidic pace that realizes the non-aggregating property by non-fluidity. Is to provide. Moreover, it is providing the manufacturing method of the non-fluid paste, and providing the joining method using a non-fluid paste simultaneously.
　本発明は上記課題を解決するためになされたものであり、本発明の第１形態は、銀原子の集合体からなる銀核の周囲に、炭素数１０又は１２いずれかのアルコール分子残基、アルコール分子誘導体及び／又はアルコール分子の一種以上からなる有機被覆層を形成した複合銀ナノ粒子と、銀微粒子と、樹脂を混合して構成され、前記樹脂は３０℃以下で非流動状態にあって前記複合銀ナノ粒子と前記銀微粒子を均一分散状態に保持し、加熱により流動化して塗着可能になる複合銀ナノペーストである。本発明の樹脂とは、３０℃以下で非流動状態にあって加熱により流動化する物質を云い、前記非流動状態とは固体状態又は高粘度状態の両者を包含する概念である。特に、高温加熱により蒸発又は分解して炭化などの残留物が無いか、又は残留量が少ない物質を云う。前記樹脂の概念は本明細書を通して一貫している。従って、本発明の樹脂は、一般化学概念の樹脂とは異なる。 The present invention has been made in order to solve the above problems, and the first form of the present invention is an alcohol molecule residue having either 10 or 12 carbon atoms around a silver nucleus composed of an aggregate of silver atoms. A composite silver nanoparticle formed with an organic coating layer composed of one or more alcohol molecule derivatives and / or alcohol molecules, silver fine particles, and a resin are mixed, and the resin is in a non-flowing state at 30 ° C. or less. It is a composite silver nanopaste in which the composite silver nanoparticles and the silver fine particles are kept in a uniformly dispersed state and fluidized by heating and can be applied. The resin of the present invention refers to a substance that is in a non-flowing state at 30 ° C. or less and fluidizes by heating, and the non-flowing state is a concept including both a solid state and a high viscosity state. In particular, it refers to a substance that is evaporated or decomposed by high-temperature heating and has no residue such as carbonization or a small amount of residue. The concept of resin is consistent throughout the specification. Therefore, the resin of the present invention is different from the resin of the general chemical concept.
　本発明の第２形態は、前記第１形態において、前記銀核の平均粒径は１～２０ｎｍであり、前記銀微粒子の平均粒径は０．１～３．０μｍである複合銀ナノペーストである。 A second aspect of the present invention is a composite silver nanopaste according to the first aspect, wherein the average particle diameter of the silver nuclei is 1 to 20 nm and the average particle diameter of the silver fine particles is 0.1 to 3.0 μm. is there.
　本発明の第３形態は、前記第１又は第２形態において、前記複合銀ナノ粒子の重量は５～３０（ｗｔ％）、前記銀微粒子の重量は６０～９０（ｗｔ％）であり、前記樹脂の重量は１５（ｗｔ％）以下である複合銀ナノペーストである。 According to a third aspect of the present invention, in the first or second aspect, the weight of the composite silver nanoparticles is 5 to 30 (wt%), the weight of the silver fine particles is 60 to 90 (wt%), The composite silver nanopaste has a resin weight of 15 (wt%) or less.
　本発明の第４形態は、前記第３形態において、全体として銀含有率が８０（ｗｔ％）以上である複合銀ナノペーストである。 The fourth form of the present invention is a composite silver nanopaste having a silver content of 80 (wt%) or more as a whole in the third form.
　本発明の第５形態は、前記第１～第４形態のいずれかにおいて、所望量の溶剤を添加して、３０℃以下でも流動状態化させて塗着可能にする複合銀ナノペーストである。 A fifth form of the present invention is a composite silver nanopaste according to any one of the first to fourth forms, wherein a desired amount of a solvent is added to make it flowable even at 30 ° C. or less and can be applied.
　本発明の第６形態は、前記第１～第５形態のいずれかにおいて、基体に塗着し、窒素雰囲気下で２５０～５００℃の温度で焼成して有機物を気散させて銀膜を形成したときに、前記銀膜と基体との接合面積割合が７０％以上であり、前記銀膜の比抵抗が１０（μΩｃｍ）以下である複合銀ナノペーストである。 A sixth aspect of the present invention is the method according to any one of the first to fifth aspects, wherein the silver film is formed by applying to a substrate and baking at a temperature of 250 to 500 ° C. in a nitrogen atmosphere to disperse the organic matter. The composite silver nanopaste has a bonding area ratio between the silver film and the substrate of 70% or more and a specific resistance of the silver film of 10 (μΩcm) or less.
　本発明の第７形態は、銀原子の集合体からなる銀核の周囲に、炭素数１０又は１２いずれかのアルコール分子残基、アルコール分子誘導体及び／又はアルコール分子の一種以上からなる有機被覆層を形成した所定量の複合銀ナノ粒子を、３０℃以下で非流動状態にあり加熱により流動化する所定量の樹脂に添加し、前記樹脂が流動状態になる温度で均一分散するまで混練してペースト中間体を形成し、このペースト中間体に所定量の銀微粒子を添加して前記温度で均一分散するまで混練し、混練後に前記樹脂が非流動状態になる温度まで冷却して、前記複合銀ナノ粒子と前記銀微粒子を前記樹脂中に均一分散状態に保持する複合銀ナノペーストの製法である。 In the seventh aspect of the present invention, an organic coating layer comprising at least one alcohol molecule residue, alcohol molecule derivative and / or alcohol molecule having 10 or 12 carbon atoms around a silver nucleus composed of an aggregate of silver atoms. Is added to a predetermined amount of resin that is in a non-flowing state at 30 ° C. or less and fluidized by heating, and kneaded until the resin is uniformly dispersed at a temperature at which the resin is in a flowing state. Forming a paste intermediate, adding a predetermined amount of silver fine particles to the paste intermediate, kneading until uniformly dispersed at the temperature, cooling to a temperature at which the resin becomes non-flowing after the kneading, the composite silver This is a method for producing a composite silver nanopaste in which nanoparticles and the silver fine particles are kept in a uniformly dispersed state in the resin.
　本発明の第８形態は、所定量の銀微粒子を、３０℃以下で非流動状態にあり加熱により流動化する所定量の樹脂に添加し、前記樹脂が流動状態になる温度で均一分散するまで混練してペースト中間体を形成し、このペースト中間体に、銀原子の集合体からなる銀核の周囲に、炭素数１０又は１２いずれかのアルコール分子残基、アルコール分子誘導体及び／又はアルコール分子の一種以上からなる有機被覆層を形成した所定量の複合銀ナノ粒子を添加して前記温度で均一分散するまで混練し、混練後に前記樹脂が非流動状態になる温度まで冷却して、前記複合銀ナノ粒子と前記銀微粒子を前記樹脂中に均一分散状態に保持する複合銀ナノペーストの製法である。 In an eighth embodiment of the present invention, a predetermined amount of silver fine particles is added to a predetermined amount of resin that is in a non-flowing state at 30 ° C. or less and fluidized by heating, and is uniformly dispersed at a temperature at which the resin is in a flowing state. A paste intermediate is formed by kneading, and an alcohol molecule residue, alcohol molecule derivative and / or alcohol molecule having either 10 or 12 carbon atoms is disposed around the silver nucleus composed of an aggregate of silver atoms. A predetermined amount of composite silver nanoparticles formed with an organic coating layer composed of one or more of the above are added and kneaded until uniformly dispersed at the temperature, cooled to a temperature at which the resin becomes non-flowable after kneading, and the composite This is a method for producing a composite silver nanopaste in which silver nanoparticles and silver fine particles are maintained in a uniformly dispersed state in the resin.
　本発明の第９形態は、銀原子の集合体からなる銀核の周囲に、炭素数１０又は１２のアルコール分子残基、アルコール分子誘導体又はアルコール分子の一種以上からなる有機被覆層を形成した所定量の複合銀ナノ粒子と、所定量の銀微粒子を、３０℃以下で非流動状態にあり加熱により流動化する所定量の樹脂に添加し、前記樹脂が流動状態になる温度で均一分散するまで混練し、混練後に前記樹脂が非流動状態になる温度まで冷却して、前記複合銀ナノ粒子と前記銀微粒子を前記樹脂中に均一分散状態に保持する複合銀ナノペーストの製法である。 In the ninth embodiment of the present invention, an organic coating layer composed of one or more alcohol molecule residues, alcohol molecule derivatives or alcohol molecules having 10 or 12 carbon atoms is formed around a silver nucleus composed of an aggregate of silver atoms. A fixed amount of composite silver nanoparticles and a predetermined amount of silver fine particles are added to a predetermined amount of resin that is in a non-flowing state at 30 ° C. or less and fluidized by heating, and is uniformly dispersed at a temperature at which the resin is in a flowing state. This is a method for producing a composite silver nanopaste, which is kneaded and cooled to a temperature at which the resin becomes non-flowing after kneading to keep the composite silver nanoparticles and the silver fine particles in a uniformly dispersed state in the resin.
　本発明の第１０形態は、前記第７～第９形態のいずれかにおいて、前記銀核の平均粒径は１～２０ｎｍ、前記銀微粒子の平均粒径は０．１～３．０μｍである複合銀ナノペーストの製法である。 A tenth aspect of the present invention is the composite according to any one of the seventh to ninth aspects, wherein the average particle diameter of the silver nuclei is 1 to 20 nm and the average particle diameter of the silver fine particles is 0.1 to 3.0 μm. It is a manufacturing method of silver nano paste.
　本発明の第１１形態は、前記第７～第１０形態のいずれかにおいて、前記複合銀ナノ粒子の前記所定量は５～３０（ｗｔ％）、前記銀微粒子の前記所定量は６０～９０（ｗｔ％）、前記樹脂の前記所定量は１５（ｗｔ％）以下であり、全体として銀含有率が８０（ｗｔ％）以上である複合銀ナノペーストの製法である。 In an eleventh aspect of the present invention, in any one of the seventh to tenth aspects, the predetermined amount of the composite silver nanoparticles is 5 to 30 (wt%), and the predetermined amount of the silver fine particles is 60 to 90 ( wt%), the predetermined amount of the resin is 15 (wt%) or less, and the overall silver content is 80 (wt%) or more.
　本発明の第１２形態は、前記第７～第１１形態のいずれかにおいて、所望量の溶剤を添加して、３０℃以下でも流動状態化させて塗着可能なペーストにする複合銀ナノペーストの製法である。 A twelfth aspect of the present invention is the composite silver nanopaste according to any one of the seventh to eleventh aspects, wherein a desired amount of a solvent is added to make a paste that can be applied by being fluidized at 30 ° C. or lower. It is a manufacturing method.
　本発明の第１３形態は、前記第１～第６形態のいずれかの流動状態にある複合銀ナノペーストを用意し、前記複合銀ナノペーストを下部基体上に塗着して接合用ペースト層を形成し、及び／又は前記接合用ペースト層の上に上部基体を載置して接合体を形成し、前記接合体を窒素雰囲気下及び／又は無荷重下で２５０～５００℃の温度で焼成するナノペースト接合方法である。 In a thirteenth aspect of the present invention, a composite silver nanopaste in a fluid state of any one of the first to sixth forms is prepared, and the composite silver nanopaste is applied onto a lower substrate to form a bonding paste layer. Forming and / or placing an upper substrate on the joining paste layer to form a joined body, and firing the joined body at a temperature of 250 to 500 ° C. in a nitrogen atmosphere and / or under no load. This is a nanopaste bonding method.
　本発明の第１４形態は、前記第１３形態において、前記上部基体は半導体素子であるナノペースト接合方法である。 The fourteenth aspect of the present invention is the nanopaste bonding method according to the thirteenth aspect, wherein the upper substrate is a semiconductor element.
　本発明の第１形態によれば、銀原子の集合体からなる銀核の周囲に、炭素数１０又は１２いずれかのアルコール分子残基、アルコール分子誘導体及び／又はアルコール分子の一種以上からなる有機被覆層を形成した複合銀ナノ粒子を用いるから、安価な複合銀ナノペーストを提供できる。前記複合銀ナノペーストは、例えば、比較的安価な炭酸銀とアルコールを出発原料とし、アルコールの中でも比較的安価な炭素数１０又は１２のアルコールを使用するから、安価な複合銀ナノ粒子を利用できる。しかも、Ｃ１０又はＣ１２であるから、炭素数は比較的少なく、複合銀ナノ粒子における銀含有率が比較的高い特徴がある。前記複合銀ナノ粒子は、以下ではＣｎＡｇＡＬ（ｎ＝１０、１２）と書いたり、Ｃ１０ＡｇＡＬ、Ｃ１２ＡｇＡＬと書く場合もある。その意味は、炭素数ｎ＝１０又は１２の銀アルコラート型の複合銀ナノ粒子である。Ｃ１０はデカノール、Ｃ１２はドデカノールを意味している。つまり、銀原子の集合体である銀核の周囲に、多数のＣ１０アルコラート基からなる有機被覆層を有する複合銀ナノ粒子をＣ１０ＡｇＡＬと書き、多数のＣ１２アルコラート基からなる有機被覆層を有する複合銀ナノ粒子をＣ１２ＡｇＡＬと書く。アルコール残基とは、例えばアルコールをＣｎＨ２ｎ＋１ＯＨと書くと、そのアルコラート基ＣｎＨ２ｎ＋１Ｏ等を含む概念である。アルコール誘導体とは、例えばカルボン酸などを含む概念である。アルコールとはＣｎＨ２ｎ＋１ＯＨ自体を云う。 According to the first embodiment of the present invention, an organic substance composed of one or more alcohol molecule residues, alcohol molecule derivatives and / or alcohol molecules having 10 or 12 carbon atoms around a silver nucleus composed of an aggregate of silver atoms. Since composite silver nanoparticles having a coating layer are used, an inexpensive composite silver nanopaste can be provided. The composite silver nanopaste uses, for example, relatively inexpensive silver carbonate and alcohol as starting materials, and uses a relatively inexpensive alcohol having 10 or 12 carbon atoms, so that inexpensive composite silver nanoparticles can be used. . Moreover, since it is C10 or C12, the number of carbon atoms is relatively small, and the silver content in the composite silver nanoparticles is relatively high. Hereinafter, the composite silver nanoparticles may be written as CnAgAL (n = 10, 12), or as C10AgAL or C12AgAL. The meaning is silver alcoholate-type composite silver nanoparticles having n = 10 or 12 carbon atoms. C10 means decanol, and C12 means dodecanol. That is, a composite silver nanoparticle having an organic coating layer composed of a large number of C10 alcoholate groups around a silver nucleus that is an aggregate of silver atoms is written as C10AgAL, and a composite silver having an organic coating layer composed of a large number of C12 alcoholate groups The nanoparticles are written as C12AgAL. The alcohol residue is a concept including, for example, an alcoholate group CnH2n + 1O when the alcohol is written as CnH2n + 1OH. The alcohol derivative is a concept including, for example, carboxylic acid. Alcohol refers to CnH2n + 1OH itself.
　銀微粒子はサブミクロン～ミクロンサイズの粒径を有し、前記複合銀ナノ粒子は銀微粒子間の接着剤の役割を奏すると考えられる。銀微粒子が含有される銀の主成分である。銀微粒子の表面に前記複合銀ナノ粒子が付着し、焼成により有機成分が気散して、表面融解した銀核が表面融解した銀微粒子同士を相互に結合させるのである。
　本発明では、樹脂の機能に最大の特徴がある。前記樹脂は３０℃以下で非流動状態にあって前記複合銀ナノ粒子と前記銀微粒子を分散状態に保持し、加熱により流動化する性質を有する。前記非流動状態とは、固体状態又は高粘度状態を意味し、前記複合銀ナノ粒子と前記銀微粒子を分散状態に固定的に保持する性質を云う。３０℃以下とは、通常室温領域であり、室温で保管する場合には、ペーストは非流動状態にあり、内部に分散した複合銀ナノ粒子や銀微粒子は樹脂によりペースト内で固定され、相互に凝集することはできない。即ち、３０℃以下の室温で本発明のペーストを長期保存した場合、樹脂が非流動状態にあるから、樹脂中で銀微粒子と複合銀ナノ粒子が固定状態に保持され、それら粒子が相互に凝集することができず、ペースト保存中に粒子相互が凝集して団子化することが完全に防止される。この非流動性ペーストを非凝集性ペーストと称することができる。しかし、例えば４０℃以上に加熱すると、樹脂が液化したり急激に粘性が低下して流動状態になり、ペーストとして対象物に塗着可能になる。従って、本発明のペーストを製造した後は３０℃以下で保存して非凝集化（非流動化）しておく。ペーストを対象物に塗着する直前に加熱して流動化させて流動性ペーストにし、この流動性ペーストを対象物に塗着すれば、金属分（銀分）が凝集していないから極めて緻密な銀膜を形成することが可能になる。余った流動性ペーストは直ちに３０℃以下に冷却すれば、非凝集性ペーストとして長期保存することが出来る。加熱により高粘度から低粘度に変化する樹脂として、例えばイソボルニルシクロヘキサノール（松脂状と称する）やグリセリン（シロップ状と称する）がある。３０℃以下で固体であり、加熱すると液体化する樹脂として、例えばミリスチルアルコール（Ｃ１４）、パルミチルアルコール（Ｃ１６）、ステアリルアルコール（Ｃ１８）、ベヘニルアルコール（Ｃ２２）といったアルコール類、その他の物質が利用できる。これらの樹脂は、焼成したときに全ての成分が気散するか、又は炭化物などの残留物が極めて少ない性質を有することが必要であり、この性質により焼成により形成される銀膜の電気伝導性や熱伝導性を格段に向上できる。 The silver fine particles have a particle size of submicron to micron size, and the composite silver nanoparticles are considered to play a role of an adhesive between the silver fine particles. It is a main component of silver containing silver fine particles. The composite silver nanoparticles adhere to the surface of the silver fine particles, the organic components are diffused by firing, and the silver fine particles whose surfaces are melted are bonded to each other.
In the present invention, the resin has the greatest feature. The resin has a property of being in a non-flowing state at 30 ° C. or less, holding the composite silver nanoparticles and the silver fine particles in a dispersed state, and fluidizing by heating. The non-flowing state means a solid state or a high-viscosity state, and refers to a property of holding the composite silver nanoparticles and the silver fine particles fixedly in a dispersed state. The temperature of 30 ° C. or lower is usually in the room temperature region, and when stored at room temperature, the paste is in a non-flowing state, and composite silver nanoparticles and silver fine particles dispersed inside are fixed in the paste by a resin, It cannot aggregate. That is, when the paste of the present invention is stored for a long time at a room temperature of 30 ° C. or lower, since the resin is in a non-flowing state, the silver fine particles and the composite silver nanoparticles are held in a fixed state in the resin, and the particles aggregate together. In other words, it is possible to completely prevent the particles from aggregating and dumping during paste storage. This non-flowable paste can be referred to as a non-cohesive paste. However, for example, when heated to 40 ° C. or higher, the resin is liquefied or the viscosity is suddenly lowered to be in a fluid state, and can be applied to an object as a paste. Accordingly, after the paste of the present invention is produced, it is stored at 30 ° C. or lower to be non-aggregated (non-fluidized). Just before applying the paste to the object, it is heated and fluidized to make a fluid paste, and if this fluid paste is applied to the object, the metal (silver) is not agglomerated so it is extremely dense. A silver film can be formed. If the remaining fluid paste is immediately cooled to 30 ° C. or less, it can be stored for a long time as a non-aggregating paste. Examples of the resin that changes from a high viscosity to a low viscosity by heating include isobornylcyclohexanol (referred to as rosin) and glycerin (referred to as syrup). As resins that are solid at 30 ° C. or lower and liquefy when heated, alcohols such as myristyl alcohol (C14), palmityl alcohol (C16), stearyl alcohol (C18), and behenyl alcohol (C22), and other substances can be used. . These resins must have the property that all components are diffused when baked or there are very few residues such as carbides, and due to this property the electrical conductivity of the silver film formed by calcination And thermal conductivity can be greatly improved.
　通常のペーストでは、複合銀ナノ粒子を分散させるために分散剤を添加したり、界面活性剤を添加するが、これらの不純物有機物を添加すると、銀含有量が低下するだけでなく、焼成すると前記不純物有機物から大量のガスが発生し、このガスにより銀膜中に大量のボイド（気泡の抜け孔）が形成され、電気伝導度が低下すると同時に、基体との接合力が低下し、銀膜による接合性能が低下する。これに対し、本発明では樹脂以外の有機物を添加しないから、銀含有率を高く保持できると同時に、発生ガス量が少なく、必然的にボイド数が少なくなり、接合力の増大と電気伝導度及び熱伝導度を増大化できる効果がある。 In a normal paste, a dispersant is added to disperse the composite silver nanoparticles, or a surfactant is added. However, when these impurity organic substances are added, not only the silver content is lowered, but also when fired, A large amount of gas is generated from the impurity organic substance, and a large amount of voids (bubble voids) are formed in the silver film by this gas. At the same time, the electrical conductivity is lowered and the bonding force with the substrate is lowered. Bonding performance is reduced. On the other hand, since organic substances other than resin are not added in the present invention, the silver content can be kept high, and at the same time, the amount of generated gas is small, the number of voids is inevitably reduced, the increase in bonding force and electrical conductivity and There is an effect that the thermal conductivity can be increased.
　本発明の第２の形態によれば、前記銀核の平均粒径は１～２０ｎｍであり、前記銀微粒子の平均粒径は０．１～３．０μｍであるから、大きな銀微粒子間の隙間に複合銀ナノペーストが集積して、焼成して有機物が気散したときに、銀微粒子間の隙間が銀核によって充填され、しかも銀微粒子相互が銀核によって接着されるため、銀膜自体が緻密に形成されて高強度で高電気伝導性を有する導体が提供される。前述した粒径関係にあると、銀核が銀微粒子同士の隙間を充填し、ガスが気散した後の気泡空洞（ボイド）に銀核が埋め戻される形態になり、ボイド発生数が少なくなる結果、基体との接合強度及び電気伝導度の向上を図ることが出来る。 According to the second aspect of the present invention, the average particle diameter of the silver nuclei is 1 to 20 nm, and the average particle diameter of the silver fine particles is 0.1 to 3.0 μm. When the composite silver nanopaste accumulates and baked and organic matter is diffused, the gap between the silver fine particles is filled with silver nuclei, and the silver fine particles are bonded to each other by the silver nuclei. A conductor that is densely formed and has high strength and high electrical conductivity is provided. When the particle size relationship is as described above, the silver nuclei fill the gaps between the silver fine particles, and the gas nuclei are filled back into the bubble cavities (voids), and the number of voids is reduced. As a result, it is possible to improve the bonding strength and electrical conductivity with the substrate.
　本発明の第３形態によれば、前記複合銀ナノ粒子の重量は５～３０（ｗｔ％）、前記銀微粒子の重量は６０～９０（ｗｔ％）であり、前記樹脂の重量は１５（ｗｔ％）以下であるから、高銀含有率の複合銀ナノペーストを提供できる。接着剤の役割を果たす前記複合銀ナノ粒子の重量が５（ｗｔ％）以下では銀微粒子相互の接着強度が小さくなり、３０（ｗｔ％）以上ではペーストが高価格になると同時に、有機物量が多くなってボイドの発生量がやや増大する。また、複合銀ナノ粒子は、Ｃ１０又はＣ１２であるから、上述したように銀含有率が比較的高い。また、最大重量を占める銀微粒子は純銀であるから、ペースト全体における銀含有率を一層に高くでき、電気伝導度の増大化を実現できる。銀微粒子の重量が６０（ｗｔ％）以下になると、相対的に銀含有率が低下し、９０（ｗｔ％）以上では、接着剤となる複合銀ナノ粒子が少なくなり、銀粒子間の接着強度が低下する傾向がある。そして、有機分である樹脂は１５（ｗｔ％）以下と少ないから、有機物含量が少なく、ペースト膜を焼成したときに、発生するガスは少なく、後に残るボイド（気泡空洞）が少なくなる。銀含有率が大きくなるほど、発生ガスは少なく、ボイドが少なくなるのは理の当然である。ボイドが少ない分だけ、銀膜と基体との接合面積割合は大きくなり、電気伝導性が高く、接合強度の高い銀膜を形成することができる。 According to the third aspect of the present invention, the weight of the composite silver nanoparticles is 5 to 30 (wt%), the weight of the silver fine particles is 60 to 90 (wt%), and the weight of the resin is 15 (wt %) Or less, a composite silver nanopaste with a high silver content can be provided. When the weight of the composite silver nanoparticle serving as an adhesive is 5 (wt%) or less, the adhesive strength between the silver fine particles is small, and when it is 30 (wt%) or more, the paste becomes expensive and the amount of organic matter is large. As a result, the amount of voids is slightly increased. Moreover, since the composite silver nanoparticles are C10 or C12, the silver content is relatively high as described above. Further, since the silver fine particles occupying the maximum weight are pure silver, the silver content in the entire paste can be further increased, and the electrical conductivity can be increased. When the weight of the silver fine particles is 60 (wt%) or less, the silver content is relatively lowered. When the weight is 90 (wt%) or more, the composite silver nanoparticles serving as an adhesive are reduced, and the adhesive strength between the silver particles is reduced. Tends to decrease. Since the organic resin is as small as 15 wt% or less, the organic content is low, and when the paste film is baked, less gas is generated and less voids (bubble cavities) remain afterwards. Naturally, the higher the silver content, the less gas is generated and the fewer voids. The smaller the voids, the larger the bonding area ratio between the silver film and the substrate, and it is possible to form a silver film with high electrical conductivity and high bonding strength.
　本発明の第４形態によれば、全体として銀含有率が８０（ｗｔ％）以上の複合銀ナノペーストを提供できる。銀含有率が８０（ｗｔ％）未満になると、有機物含有率が２０（ｗｔ％）以上になり、焼成時の発生ガス量が増大して、ボイド量が増加し、有効な接合強度と電気伝導度が得られなくなる。銀含有率は、８５（ｗｔ％）以上が好ましく、９０（ｗｔ％）以上であれば最も好ましく、半導体接合やパターン形成等の分野でも画期的なペーストを提供できる。 According to the fourth embodiment of the present invention, a composite silver nanopaste having a silver content of 80 (wt%) or more as a whole can be provided. When the silver content is less than 80 (wt%), the organic content becomes 20 (wt%) or more, the amount of gas generated during firing increases, the amount of voids increases, and effective bonding strength and electrical conduction. The degree cannot be obtained. The silver content is preferably 85 (wt%) or more, most preferably 90 (wt%) or more, and can provide an innovative paste in the fields of semiconductor bonding and pattern formation.
　本発明の第５形態によれば、所望量の溶剤を添加して、３０℃以下でも流動状態化させて塗着可能にする複合銀ナノペーストが提供される。第１形態では、樹脂だけを添加したペーストが提供され、３０℃以下でペーストを保存しても、ペーストには流動性が無いから、この非流動性ペースト内で複合銀ナノ粒子や銀微粒子は固定化され、相互の凝集は発生せず、非凝集性ペーストである。相当期間だけ非凝集性ペースト、即ち非流動性ペーストとして保管した後、ペーストを接合する直前に、本第５形態の溶剤を添加して流動化させ、ディスペンサーにより流動性ペーストを基体に塗着させることができる。非流動性ペーストを流動化させるためには、加熱する場合と、溶剤を添加する場合の二つの方法がある。溶剤を添加する本形態では、ペースト内での有機物含量が増えるから、焼成によるガスが増大し、ボイド発生量が増える弱点がある。しかし、塗着する直前に溶剤を添加すれば、複合銀ナノ粒子が凝集して２次粒子化（つまり団子化）することを避けることは可能になる。 According to the fifth embodiment of the present invention, there is provided a composite silver nanopaste that can be applied by adding a desired amount of solvent to make it flowable even at 30 ° C. or lower. In the first embodiment, a paste to which only a resin is added is provided, and even if the paste is stored at 30 ° C. or lower, the paste does not have fluidity. They are fixed and do not cause mutual aggregation, and are non-aggregating pastes. After being stored as a non-aggregating paste for a considerable period, that is, as a non-fluid paste, immediately before joining the paste, the solvent of the fifth embodiment is added and fluidized, and the fluid paste is applied to the substrate by a dispenser. be able to. In order to fluidize the non-fluid paste, there are two methods: heating and adding a solvent. In the present embodiment in which a solvent is added, the organic matter content in the paste increases, so there is a weak point that the amount of gas generated by firing increases and the amount of void generation increases. However, if a solvent is added immediately before coating, it is possible to avoid the composite silver nanoparticles from agglomerating into secondary particles (ie, dumpling).
　本発明の第６形態によれば、基体に塗着し、窒素雰囲気下で２５０～５００℃の温度で焼成して有機物を気散させて銀膜を形成したときに、前記銀膜と基体との接合面積割合が７０％以上であり、前記銀膜の比抵抗が１０（μΩｃｍ）以下である複合銀ナノペーストを提供できる。窒素雰囲気下で焼成すると、ペースト内の有機物は酸化されず、加熱により有機物は蒸発して気散されることが本発明者等の研究により明らかになった。複合銀ナノ粒子の場合、窒素雰囲気下では、銀核の周囲に結合したアルコラート基がアルコラート基単体で銀核から蒸発し、殆んど分解しないことが分かった。また、窒素雰囲気下では、樹脂成分も加熱により分解しないで蒸発して気散される。分解されないから、発生ガス量は少なく、ボイド発生量も必然的に少なくなる。その結果、銀膜と基体との接合面積割合は増大し、同時に接合強度と電気伝導度が増大する効果が得られる。従って、窒素雰囲気下では、銀膜と基体との接合面積割合が７０％以上であれば、前記銀膜の比抵抗が１０（μΩｃｍ）に調整でき、好適には接合面積割合を８０％以上にすることにより、比抵抗を例えば８（μΩｃｍ）以下まで低下することができ、更に好適には接合面積割合を９０％以上にすることにより、比抵抗を例えば５（μΩｃｍ）以下まで低下させて純銀の比抵抗に接近させることが可能になる。また、有機物の蒸発温度は、空気による酸化温度よりも低いから、空気下焼成よりも焼成温度を低下でき、低温焼成を可能にする利点がある。更に、空気下焼成では、有機物が酸化されるため、有機物は分解されてＣＯ２やＨ２Ｏとなって気散する結果、１モルの有機物が２モル、３モルと増加し、大量のガス発生によりボイド発生量が窒素雰囲気下とは比較できないほど増大する弱点がある。これに対し、上述したように、窒素雰囲気下ではガスの発生量を抑制でき、ボイドが少なく、接合面積割合が増大し、接合強度と電気伝導度の増大を実現することができる。 According to the sixth aspect of the present invention, when a silver film is formed by applying an organic substance to a base material and baking it at a temperature of 250 to 500 ° C. in a nitrogen atmosphere to form the silver film, A composite silver nanopaste having a bonding area ratio of 70% or more and a specific resistance of the silver film of 10 (μΩcm) or less can be provided. Research by the present inventors has revealed that, when baked in a nitrogen atmosphere, the organic matter in the paste is not oxidized and the organic matter is evaporated and diffused by heating. In the case of composite silver nanoparticles, it was found that in a nitrogen atmosphere, the alcoholate group bonded around the silver nucleus evaporates from the silver nucleus by the alcoholate group alone and hardly decomposes. In a nitrogen atmosphere, the resin component is also evaporated and diffused without being decomposed by heating. Since it is not decomposed, the amount of gas generated is small, and the amount of void generation is inevitably small. As a result, the bonding area ratio between the silver film and the substrate is increased, and at the same time, the effect of increasing the bonding strength and electrical conductivity is obtained. Therefore, in a nitrogen atmosphere, if the bonding area ratio between the silver film and the substrate is 70% or more, the specific resistance of the silver film can be adjusted to 10 (μΩcm), and preferably the bonding area ratio is 80% or more. Thus, the specific resistance can be reduced to, for example, 8 (μΩcm) or less, and more preferably, the specific resistance is decreased to, for example, 5 (μΩcm) or less by setting the junction area ratio to 90% or more. It is possible to approach the specific resistance. Further, since the evaporation temperature of the organic substance is lower than the oxidation temperature by air, there is an advantage that the firing temperature can be lowered and firing at a low temperature is possible as compared with firing in air. Furthermore, since the organic matter is oxidized in firing in the air, the organic matter is decomposed and diffused as CO2 or H2O. As a result, 1 mol of organic matter increases to 2 mol and 3 mol, and a large amount of gas is generated to generate voids. There is a weak point that the amount of generation increases so that it cannot be compared with that in a nitrogen atmosphere. On the other hand, as described above, the amount of gas generated can be suppressed under a nitrogen atmosphere, the number of voids can be reduced, the bonding area ratio can be increased, and the bonding strength and electrical conductivity can be increased.
　前述したように、窒素雰囲気下では、有機物質が有機分子として蒸発するから、蒸発熱を吸収しながら蒸発するため、ペースト中で局所的には冷却される場合も有り、残留する銀核の熱振動は小さく、銀核は緩慢に銀微粒子間の隙間に移動して銀膜の緻密化と、ボイド数の低減化に寄与すると考えられる。これに対し、空気下で焼成した場合には、有機物の酸化反応により発熱し、この発生熱が銀核の熱振動を加速する結果、銀核が銀微粒子間の隙間を埋めるように移動しないと考えられる。従って、窒素雰囲気下での焼成が空気下での焼成より銀膜の緻密化とボイド数の低減や、接合強度と電気伝導度の向上に効果があると云える。 As described above, in a nitrogen atmosphere, the organic substance evaporates as organic molecules, and thus evaporates while absorbing the heat of evaporation, so it may be locally cooled in the paste and the heat of the remaining silver nuclei. It is considered that the vibration is small and the silver nuclei slowly move into the gaps between the silver fine particles, contributing to the densification of the silver film and the reduction in the number of voids. On the other hand, when baked in air, heat is generated by the oxidation reaction of organic matter, and this generated heat accelerates the thermal vibration of the silver nuclei, so that the silver nuclei do not move so as to fill the gaps between the silver fine particles. Conceivable. Therefore, it can be said that firing in a nitrogen atmosphere is more effective in densifying the silver film and reducing the number of voids, and improving the bonding strength and electrical conductivity than firing in the air.
　本発明の第７形態によれば、銀原子の集合体からなる銀核の周囲に、炭素数１０又は１２いずれかのアルコール分子残基、アルコール分子誘導体及び／又はアルコール分子の一種以上からなる有機被覆層を形成した所定量の複合銀ナノ粒子を、３０℃以下で非流動状態にあり加熱により流動化する所定量の樹脂に添加し、前記樹脂が流動状態になる温度で均一分散するまで混練してペースト中間体を形成し、このペースト中間体に所定量の銀微粒子を添加して前記温度で均一分散するまで混練し、混練後に前記樹脂が非流動状態になる温度まで冷却して、前記複合銀ナノ粒子と前記銀微粒子を前記樹脂中に均一分散状態に保持する非凝集性の複合銀ナノペーストの製法が提供できる。加熱温度は樹脂が流動化する温度であり、しかも有機物が蒸発しない温度以下で調整される。まず、複合銀ナノ粒子と樹脂を均一に混練し、その次に銀微粒子を添加して均一に混練する。ヒーターにより加熱しなくても、混練する際の摩擦熱によりペースト温度が上昇し、例えば４０℃位まで上昇すると自然にペーストが流動化し均一混練が可能になるから、強制加熱でなくても摩擦加熱（自然加熱）でも流動化を発現できる。また、先に複合銀ナノ粒子と樹脂の二者を混練すると、ナノサイズの複合銀ナノ粒子が樹脂中に均一に分散しやすい。この後に、ミクロンサイズの銀微粒子を添加して混練すると、銀微粒子が樹脂中に均一分散し、樹脂と複合銀ナノ粒子と銀微粒子の三者が独立的に均一に分散したペーストを作り易い。混練方法には公知の混連装置が利用でき、自転遠心器だけでなく、自転公転遠心器なども利用できる。 According to the seventh aspect of the present invention, an organic substance comprising at least one alcohol molecule residue, alcohol molecule derivative and / or alcohol molecule having 10 or 12 carbon atoms around a silver nucleus composed of an aggregate of silver atoms. A predetermined amount of composite silver nanoparticles having a coating layer added thereto is added to a predetermined amount of resin that is in a non-flowing state at 30 ° C. or less and fluidized by heating, and is kneaded until uniformly dispersed at a temperature at which the resin is in a flowing state. Forming a paste intermediate, adding a predetermined amount of silver fine particles to the paste intermediate and kneading until uniformly dispersed at the temperature, cooling to a temperature at which the resin becomes non-flowing after kneading, A method of producing a non-aggregating composite silver nanopaste that maintains the composite silver nanoparticles and the silver fine particles in a uniformly dispersed state in the resin can be provided. The heating temperature is a temperature at which the resin is fluidized, and is adjusted below the temperature at which the organic matter does not evaporate. First, composite silver nanoparticles and resin are uniformly kneaded, and then silver fine particles are added and uniformly kneaded. Even if it is not heated by a heater, the paste temperature rises due to frictional heat during kneading. For example, if it rises to about 40 ° C, the paste will naturally flow and uniform kneading becomes possible. (Natural heating) can be fluidized. Further, when the composite silver nanoparticles and the resin are kneaded first, the nano-sized composite silver nanoparticles are easily dispersed uniformly in the resin. Thereafter, when micron-sized silver fine particles are added and kneaded, the silver fine particles are uniformly dispersed in the resin, and it is easy to make a paste in which the resin, the composite silver nanoparticles, and the silver fine particles are independently and uniformly dispersed. A known mixing device can be used for the kneading method, and not only a rotating centrifuge but also a rotating / revolving centrifuge can be used.
　本発明の第８形態によれば、所定量の銀微粒子を、３０℃以下で非流動状態にあり加熱により流動化する所定量の樹脂に添加し、前記樹脂が流動状態になる温度で均一分散するまで混練してペースト中間体を形成し、このペースト中間体に、銀原子の集合体からなる銀核の周囲に、炭素数１０又は１２いずれかのアルコール分子残基、アルコール分子誘導体及び／又はアルコール分子の一種以上からなる有機被覆層を形成した所定量の複合銀ナノ粒子を添加して前記温度で均一分散するまで混練し、混練後に前記樹脂が非流動状態になる温度まで冷却して、前記複合銀ナノ粒子と前記銀微粒子を前記樹脂中に均一分散状態に保持する非凝集性の複合銀ナノペーストの製法を提供できる。
　加熱温度は樹脂が流動化する温度であり、しかも有機物が蒸発しない温度以下で調整される。まず、銀微粒子と樹脂を均一に混練し、その次に複合銀ナノ粒子を添加して均一に混練する。ヒーターにより加熱しなくても、混練する際の摩擦熱によりペースト温度が上昇し、例えば４０℃位まで上昇すると自然にペーストが流動化し均一混練が可能になるから、強制加熱でなくても摩擦加熱（自然加熱）でも流動化を発現できる。また、先に銀微粒子と樹脂の二者を混練すると、ミクロンサイズの銀微粒子が樹脂中に均一に分散し易い。この後に、ナノサイズの複合銀ナノ粒子を添加して混練すると、複合銀ナノ粒子が樹脂中に均一分散し、樹脂と銀微粒子と複合銀ナノ粒子の三者が独立的に均一に分散したペーストを作り易い。混練方法には公知の混連装置が利用でき、自転遠心器だけでなく、自転公転遠心器なども利用できることは云うまでもない。 According to the eighth aspect of the present invention, a predetermined amount of silver fine particles is added to a predetermined amount of resin that is in a non-flowing state at 30 ° C. or less and fluidized by heating, and is uniformly dispersed at a temperature at which the resin is in a flowing state. Kneading until a paste intermediate is formed, and the paste intermediate is surrounded by an alcohol molecule residue, alcohol molecule derivative and / or carbon atom having either 10 or 12 carbon atoms around a silver nucleus composed of an aggregate of silver atoms. Add a predetermined amount of composite silver nanoparticles formed with an organic coating layer composed of one or more alcohol molecules, knead until uniformly dispersed at the temperature, cool to a temperature at which the resin becomes non-flowing after kneading, A method of producing a non-aggregating composite silver nanopaste that maintains the composite silver nanoparticles and the silver fine particles in a uniform dispersed state in the resin can be provided.
The heating temperature is a temperature at which the resin is fluidized, and is adjusted below the temperature at which the organic matter does not evaporate. First, silver fine particles and a resin are uniformly kneaded, and then composite silver nanoparticles are added and uniformly kneaded. Even if it is not heated by a heater, the paste temperature rises due to frictional heat during kneading. For example, if it rises to about 40 ° C, the paste will naturally flow and uniform kneading becomes possible. (Natural heating) can be fluidized. Further, when the silver fine particles and the resin are kneaded first, the micron-sized silver fine particles are easily dispersed uniformly in the resin. After this, when nano-sized composite silver nanoparticles are added and kneaded, the composite silver nanoparticles are uniformly dispersed in the resin, and the three of the resin, silver fine particles, and composite silver nanoparticles are independently and uniformly dispersed. Easy to make. Needless to say, a known mixing device can be used for the kneading method, and not only a rotating centrifuge but also a rotating and rotating centrifuge can be used.
　本発明の第９形態によれば、銀原子の集合体からなる銀核の周囲に、炭素数１０又は１２のアルコール分子残基、アルコール分子誘導体又はアルコール分子の一種以上からなる有機被覆層を形成した所定量の複合銀ナノ粒子と、所定量の銀微粒子を、３０℃以下で非流動状態にあり加熱により流動化する所定量の樹脂に添加し、前記樹脂が流動状態になる温度で均一分散するまで混練し、混練後に前記樹脂が非流動状態になる温度まで冷却して、前記複合銀ナノ粒子と前記銀微粒子を前記樹脂中に均一分散状態に保持する非凝集性の複合銀ナノペーストの製法が提供できる。本方法では、複合銀ナノ粒子と銀微粒子と樹脂の三者を同時一体的に混練するから、混錬に要する時間を短縮できる効果がある。ナノサイズの複合銀ナノ粒子とミクロンサイズの銀微粒子が協働的に樹脂中に分散する傾向があるが、混錬時間を長くすることによって成分三者の均一分散性を確保することができる。加熱方式は強制加熱でも、混錬による摩擦加熱でも、樹脂の流動化を発現する限りどちらでも良い。更に、混練方法には公知の混連装置が利用でき、自転遠心器だけでなく、自転公転遠心器なども利用できることは云うまでもない。 According to the ninth aspect of the present invention, an organic coating layer composed of one or more alcohol molecule residues, alcohol molecule derivatives or alcohol molecules having 10 or 12 carbon atoms is formed around a silver nucleus composed of an aggregate of silver atoms. A predetermined amount of composite silver nanoparticles and a predetermined amount of silver fine particles are added to a predetermined amount of resin that is in a non-fluid state at 30 ° C. or less and fluidized by heating, and is uniformly dispersed at a temperature at which the resin is in a fluid state Kneading until the resin is cooled to a temperature at which the resin becomes a non-flowing state after kneading, and the composite silver nanoparticles and the silver fine particles are kept in a uniformly dispersed state in the resin. Manufacturing method can be provided. In this method, the composite silver nanoparticles, the silver fine particles, and the resin are kneaded together at the same time, so that the time required for kneading can be shortened. Although nano-sized composite silver nanoparticles and micron-sized silver fine particles tend to disperse in the resin in a cooperative manner, uniform dispersibility among the three components can be ensured by increasing the kneading time. The heating method may be either forced heating or friction heating by kneading as long as the fluidization of the resin is manifested. Furthermore, it is needless to say that a known mixing device can be used for the kneading method, and not only a rotating centrifuge but also a rotating / revolving centrifuge can be used.
本発明の第１０形態によれば、前記銀核の平均粒径は１～２０ｎｍ、前記銀微粒子の平均粒径は０．１～３．０μｍの複合銀ナノペーストの製法が提供される。複合銀ナノ粒子はナノサイズで銀微粒子はミクロンサイズであるから、これらを均一に分散混合すれば、非流動性ペースト（即ち、非凝集性ペースト）内においても、複合銀ナノ粒子が銀微粒子間の隙間に充填された構造になり、焼成時には銀核が前記銀微粒子間の隙間を確実に充填する。また、ガスが気散した後の気泡空洞（ボイド）に銀核が自然に移動して埋め戻される形態になり、ボイド発生数が少なくなる結果、基体との接合面積割合や接合強度及び電気伝導度の向上を図ることが出来る。 According to a tenth aspect of the present invention, there is provided a method for producing a composite silver nanopaste having an average particle size of the silver nuclei of 1 to 20 nm and an average particle size of the silver fine particles of 0.1 to 3.0 μm. Since the composite silver nanoparticles are nano-sized and the silver fine particles are micron-sized, if they are uniformly dispersed and mixed, the composite silver nanoparticles will be located between the silver fine particles even in a non-flowable paste (ie, non-aggregating paste). In this structure, the silver nuclei reliably fill the gaps between the silver fine particles. In addition, the silver nuclei naturally move back into the bubble cavities (voids) after the gas has diffused, and the number of voids is reduced. As a result, the bonding area ratio with the substrate, bonding strength, and electrical conduction It is possible to improve the degree.
　本発明の第１１形態によれば、前記複合銀ナノ粒子の前記所定量は５～３０（ｗｔ％）、前記銀微粒子の前記所定量は６０～９０（ｗｔ％）、前記樹脂の前記所定量は１５（ｗｔ％）以下であり、全体として銀含有率が８０（ｗｔ％）以上である複合銀ナノペーストの製法が提供される。
　接着剤の役割を果たす前記複合銀ナノ粒子の重量が５（ｗｔ％）以下では銀微粒子相互の接着強度が小さくなり、３０（ｗｔ％）以上ではペーストが高価格になると同時に、有機物量が多くなってボイドの発生量がやや増大する。また、複合銀ナノ粒子は、Ｃ１０又はＣ１２であるから、上述したように銀含有率が比較的高い。また、最大重量を占める銀微粒子は純銀であるから、ペースト全体における銀含有率を一層に高くでき、電気伝導度の増大化を実現できる。銀微粒子の重量が６０（ｗｔ％）以下になると、相対的に銀含有率が低下し、９０（ｗｔ％）以上では、接着剤となる複合銀ナノ粒子が少なくなり、銀粒子間の接着強度が低下する傾向がある。そして、有機分である樹脂は１５（ｗｔ％）以下と少ないから、有機物含量が少なく、ペースト膜を焼成したときに、発生するガスは少なく、後に残るボイド（気泡空洞）が少なくなる。銀含有率が大きくなるほど、発生ガスは少なく、ボイドが少なくなるのは当然である。ボイドが少ない分だけ、銀膜と基体との接合面積割合は大きくなり、電気伝導性が高く、接合強度の高い銀膜を形成することができる。
　更に、全体として銀含有率が８０（ｗｔ％）以上の複合銀ナノペーストの製法を提供できる。銀含有率が８０（ｗｔ％）未満になると、有機物含有率が２０（ｗｔ％）以上になり、焼成時の発生ガス量が増大して、ボイド量が増加し、有効な接合強度と電気伝導度が得られなくなる。銀含有率は、８５（ｗｔ％）以上が好ましく、９０（ｗｔ％）以上であれば最も好ましく、半導体接合やパターン形成等の分野でも画期的なペーストを提供できる。 According to an eleventh aspect of the present invention, the predetermined amount of the composite silver nanoparticles is 5 to 30 (wt%), the predetermined amount of the silver fine particles is 60 to 90 (wt%), and the predetermined amount of the resin Is 15 (wt%) or less, and a method for producing a composite silver nanopaste having an overall silver content of 80 (wt%) or more is provided.
When the weight of the composite silver nanoparticle serving as an adhesive is 5 (wt%) or less, the adhesive strength between the silver fine particles is small, and when it is 30 (wt%) or more, the paste becomes expensive and the amount of organic matter is large. As a result, the amount of voids is slightly increased. Moreover, since the composite silver nanoparticles are C10 or C12, the silver content is relatively high as described above. Further, since the silver fine particles occupying the maximum weight are pure silver, the silver content in the entire paste can be further increased, and the electrical conductivity can be increased. When the weight of the silver fine particles is 60 (wt%) or less, the silver content is relatively lowered. When the weight is 90 (wt%) or more, the composite silver nanoparticles serving as an adhesive are reduced, and the adhesive strength between the silver particles is reduced. Tends to decrease. Since the organic resin is as small as 15 wt% or less, the organic content is low, and when the paste film is baked, less gas is generated and less voids (bubble cavities) remain afterwards. Naturally, the higher the silver content, the less the generated gas and the fewer voids. The smaller the voids, the larger the bonding area ratio between the silver film and the substrate, and it is possible to form a silver film with high electrical conductivity and high bonding strength.
Furthermore, the manufacturing method of the composite silver nanopaste whose silver content rate is 80 (wt%) or more as a whole can be provided. When the silver content is less than 80 (wt%), the organic content becomes 20 (wt%) or more, the amount of gas generated during firing increases, the amount of voids increases, and effective bonding strength and electrical conduction. The degree cannot be obtained. The silver content is preferably 85 (wt%) or more, most preferably 90 (wt%) or more, and can provide an innovative paste in the fields of semiconductor bonding and pattern formation.
　本発明の第１２形態によれば、所望量の溶剤を添加して、３０℃以下でも流動状態化させて塗着可能なペーストにする複合銀ナノペーストの製法が提供できる。溶剤を添加しない場合には、３０℃以下でペーストを保存しても、ペーストには流動性が無いから、この非流動性ペースト内で複合銀ナノ粒子や銀微粒子は固定化され、相互の凝集が発生しない非凝集性ペーストを実現できる。相当期間だけ非流動性ペーストとして保管した後、ペーストを接合する直前に、本形態の溶剤を添加して流動化させ、ディスペンサーにより流動性ペーストを基体に塗着させることができる。流動性ペーストとして存在する時間を短縮すればするほど、前記凝集の発生確率を低下できる。非流動性ペーストを流動化させるためには、加熱する場合と、溶剤を添加する場合の二つの方法がある。溶剤を添加する本形態では、ペースト内での有機物含量が増えるから、焼成によるガスが増大し、ボイド発生量が増える弱点がある。しかし、前述したように、塗着する直前に溶剤を添加すれば、複合銀ナノ粒子が凝集して２次粒子化（つまり団子化）することを避けることは可能になる。 According to the twelfth aspect of the present invention, there can be provided a method for producing a composite silver nanopaste that is made into a paste that can be applied by adding a desired amount of a solvent to make it flowable at 30 ° C. or lower. When no solvent is added, even if the paste is stored at 30 ° C. or lower, the paste does not have fluidity. Therefore, the composite silver nanoparticles and silver fine particles are fixed in the non-flowable paste, and are mutually agglomerated. It is possible to realize a non-cohesive paste that does not generate odor. After being stored as a non-flowable paste for a considerable period of time, immediately before joining the paste, the solvent of this embodiment can be added and fluidized, and the flowable paste can be applied to the substrate by a dispenser. The shorter the time that exists as a fluid paste, the lower the probability of occurrence of aggregation. In order to fluidize the non-fluid paste, there are two methods: heating and adding a solvent. In the present embodiment in which a solvent is added, the organic matter content in the paste increases, so there is a weak point that the amount of gas generated by firing increases and the amount of void generation increases. However, as described above, if a solvent is added immediately before coating, it is possible to avoid the composite silver nanoparticles from aggregating into secondary particles (ie, dumpling).
　本発明の第１３形態によれば、流動状態化した複合銀ナノペーストを用意し、前記複合銀ナノペーストを下部基体上に塗着して接合用ペースト層を形成し、及び／又は前記接合用ペースト層の上に上部基体を載置して接合体を形成し、前記接合体を窒素雰囲気下及び／又は無荷重下で２５０～５００℃の温度で焼成するナノペースト接合方法が提供できる。下部基体上に接合用ペースト層を形成して焼成する場合は、下部基体上に電極パターン（又は導体パターン）を形成するケースである。また、前記接合用ペースト層の上に上部基体を載置して接合体を形成して焼成する場合は、下部基体と上部基体を導体で接合するケースを意味する。本形態はこの両者を包含する。
　窒素雰囲気下で焼成すると、ペースト内の有機物は酸化されず、加熱により有機物は蒸発して気散されることが本発明者等の研究により明らかになった。複合銀ナノ粒子の場合、窒素雰囲気下では、銀核の周囲に結合したアルコラート基がアルコラート基単体で銀核から蒸発し、殆んど分解しないことが分かった。また、窒素雰囲気下では、樹脂成分も加熱により分解しないで蒸発して気散される。分解されないから、発生ガス量は少なく、ボイド発生量も必然的に少なくなる。その結果、銀膜と基体との接合面積割合は増大し、同時に接合強度と電気伝導度が増大する効果が得られる。また、有機物の蒸発温度は、空気による酸化温度よりも低いから、空気下焼成よりも焼成温度を低下でき、低温焼成を可能にする利点がある。更に、空気下焼成では、有機物が酸化されるため、有機物は分解されてＣＯ２やＨ２Ｏとなって気散する結果、１モルの有機物が２モル、３モルと増加し、大量のガス発生によりボイド発生量が窒素雰囲気下とは比較できないほど増大する弱点がある。これに対し、上述したように、窒素雰囲気下ではガスの発生量を抑制でき、ボイドが少なく、接合面積割合が増大し、接合強度と電気伝導度の増大を実現することができる。 According to the thirteenth aspect of the present invention, a composite silver nanopaste in a fluidized state is prepared, the composite silver nanopaste is applied onto the lower substrate to form a bonding paste layer, and / or the bonding There can be provided a nanopaste bonding method in which an upper substrate is placed on a paste layer to form a bonded body, and the bonded body is fired at a temperature of 250 to 500 ° C. in a nitrogen atmosphere and / or under no load. In the case where a bonding paste layer is formed on the lower substrate and fired, an electrode pattern (or conductor pattern) is formed on the lower substrate. In addition, when an upper substrate is placed on the bonding paste layer to form a bonded body and fired, it means a case where the lower substrate and the upper substrate are bonded with a conductor. This form includes both.
Research by the present inventors has revealed that, when baked in a nitrogen atmosphere, the organic matter in the paste is not oxidized and the organic matter is evaporated and diffused by heating. In the case of composite silver nanoparticles, it was found that in a nitrogen atmosphere, the alcoholate group bonded around the silver nucleus evaporates from the silver nucleus by the alcoholate group alone and hardly decomposes. In a nitrogen atmosphere, the resin component is also evaporated and diffused without being decomposed by heating. Since it is not decomposed, the amount of gas generated is small, and the amount of void generation is inevitably small. As a result, the bonding area ratio between the silver film and the substrate increases, and at the same time, the effect of increasing the bonding strength and electrical conductivity can be obtained. Further, since the evaporation temperature of the organic substance is lower than the oxidation temperature by air, there is an advantage that the firing temperature can be lowered and firing at a low temperature is possible as compared with firing in air. Furthermore, since the organic matter is oxidized in firing in the air, the organic matter is decomposed and diffused as CO2 or H2O. As a result, 1 mol of organic matter increases to 2 mol and 3 mol, and a large amount of gas is generated to generate voids There is a weak point in which the amount of generation increases so much that it cannot be compared with that in a nitrogen atmosphere. On the other hand, as described above, the amount of gas generated can be suppressed under a nitrogen atmosphere, the number of voids can be reduced, the bonding area ratio can be increased, and the bonding strength and electrical conductivity can be increased.
　前述したように、窒素雰囲気下では、有機物質が有機分子として蒸発するから、蒸発熱を吸収しながら蒸発するため、ペースト中で局所的には冷却される場合も有り、残留する銀核の熱振動は小さく、銀核は緩慢に銀微粒子間の隙間に移動して銀膜の緻密化と、ボイド数の低減化に寄与すると考えられる。これに対し、空気下で焼成した場合には、有機物の酸化反応により発熱し、この発生熱が銀核の熱振動を加速する結果、銀核が銀微粒子間の隙間を埋めるように移動しないと考えられる。従って、窒素雰囲気下での焼成が空気下での焼成より銀膜の緻密化とボイド数の低減や、接合強度と電気伝導度の向上に効果があると云える。
　また、前記接合は荷重をかけながら行うこともできるが、無荷重下でも十分な接合を行えることを確認した。即ち、無荷重下でも接合面積割合や接合強度や電気伝導度を規定範囲内で実現できることが分かった。更に、焼成温度の範囲は２５０～５００℃であり、２５０℃という低温焼成でも、５００℃という高温焼成でも本発明のぺーストを使用すれば、十分な接合を実現できることが確認された。そのことはその間の温度、即ち中間温度接合でも実用に耐える接合を実現できることを意味しており、実験的に確認されたものである。 As described above, in a nitrogen atmosphere, the organic substance evaporates as organic molecules, and thus evaporates while absorbing the heat of evaporation, so it may be locally cooled in the paste and the heat of the remaining silver nuclei. It is considered that the vibration is small and the silver nuclei slowly move into the gaps between the silver fine particles, contributing to the densification of the silver film and the reduction in the number of voids. On the other hand, when baked in air, heat is generated by the oxidation reaction of organic matter, and this generated heat accelerates the thermal vibration of the silver nuclei, so that the silver nuclei do not move so as to fill the gaps between the silver fine particles. Conceivable. Therefore, it can be said that firing in a nitrogen atmosphere is more effective in densifying the silver film and reducing the number of voids, and improving the bonding strength and electrical conductivity than firing in the air.
The joining can be performed while applying a load, but it was confirmed that sufficient joining can be performed even under no load. That is, it was found that the bonding area ratio, bonding strength, and electrical conductivity can be realized within a specified range even under no load. Further, the range of the firing temperature is 250 to 500 ° C., and it was confirmed that sufficient bonding can be realized by using the paste of the present invention even at a low temperature firing of 250 ° C. or a high temperature firing of 500 ° C. This means that a junction that can withstand practical use can be realized even at a temperature during that time, that is, an intermediate temperature junction, which has been experimentally confirmed.
　本発明の第１４形態によれば、前記上部基体は半導体素子であるナノペースト接合方法が提供される。最も簡単な例では、下部基体である回路基板に上部基体である半導体素子を接合用ペースト層で接合するケースである。この例以外の様々な接合形態が存在する。本発明のペーストを用いることによって、基板上に回路を実装することが可能になる。 According to a fourteenth aspect of the present invention, there is provided the nanopaste bonding method, wherein the upper substrate is a semiconductor element. In the simplest example, a semiconductor element as an upper substrate is bonded to a circuit board as a lower substrate with a bonding paste layer. There are various joining forms other than this example. By using the paste of the present invention, a circuit can be mounted on the substrate.
図１は複合銀ナノ粒子ＣｎＡｇＡＬの製造工程図である。FIG. 1 is a production process diagram of composite silver nanoparticles CnAgAL. 図２は複合銀ナノ粒子の生成反応の第１工程図である。FIG. 2 is a first process diagram of a formation reaction of composite silver nanoparticles. 図３は複合銀ナノ粒子の生成反応の第２工程図である。FIG. 3 is a second process diagram of the formation reaction of composite silver nanoparticles. 図４はＣ１０ＡｇＡＬの高分解能透過電子顕微鏡図である。FIG. 4 is a high-resolution transmission electron microscope view of C10AgAL. 図５はＣ１２ＡｇＡＬの高分解能透過電子顕微鏡図である。FIG. 5 is a high-resolution transmission electron microscope view of C12AgAL. 図６は銀粒子の粒径と融点の関係図である。FIG. 6 is a graph showing the relationship between the particle size and melting point of silver particles. 図７はＣ１２ＡｇＡＬの熱解析図である。FIG. 7 is a thermal analysis diagram of C12AgAL. 図８は複合銀ナノペーストの製造工程図である。FIG. 8 is a production process diagram of a composite silver nanopaste. 図９はＩＢＣＨ樹脂の粘度と温度の特性図である。FIG. 9 is a characteristic diagram of viscosity and temperature of IBCH resin. 図１０は昇温率３℃／ｍｉｎのＩＢＣＨ樹脂の熱解析図である。FIG. 10 is a thermal analysis diagram of IBCH resin with a temperature increase rate of 3 ° C./min. 図１１はＩＢＣＨ樹脂の蒸発温度と昇温率の関係図である。FIG. 11 is a relationship diagram between the evaporation temperature of the IBCH resin and the temperature rise rate. 図１２はグリセリン樹脂の粘度と温度の特性図である。FIG. 12 is a characteristic diagram of viscosity and temperature of glycerin resin. 図１３は複合銀ナノペースト（Ｐ５）の熱解析図である。FIG. 13 is a thermal analysis diagram of the composite silver nanopaste (P5). 図１４は各種ナノペーストの接合面積割合と銀含有率の関係図である。FIG. 14 is a relationship diagram of the bonding area ratio and silver content of various nanopastes. 図１５はナノペースト（Ｐ１２）のガラス面との接合図である。FIG. 15 is a joint diagram of the nanopaste (P12) with the glass surface. 図１６はナノペースト（Ｐ１６）のＣｕ面との接合図である。FIG. 16 is a bonding diagram of the nanopaste (P16) with the Cu surface. 図１７はナノペースト（Ｐ１９）のガラス面との接合図である。FIG. 17 is a bonding diagram of the nanopaste (P19) to the glass surface. 図１８はペースト焼成昇温プログラムでの温度時間関係図である。FIG. 18 is a temperature time relationship diagram in the paste firing temperature raising program. 図１９はナノペースト（Ｐ２０－２）の空気中焼成における熱解析図である。FIG. 19 is a thermal analysis diagram of the nanopaste (P20-2) in air firing. 図２０はナノペースト（Ｐ２０－２）の窒素中焼成における熱解析図である。FIG. 20 is a thermal analysis diagram of baking of the nanopaste (P20-2) in nitrogen. 図２１はナノペースト（Ｐ２１）の空気中焼成における熱解析図である。FIG. 21 is a thermal analysis diagram in the air firing of the nanopaste (P21). 図２２はナノペースト（Ｐ２１）の窒素中焼成における熱解析図である。FIG. 22 is a thermal analysis diagram in the firing of the nanopaste (P21) in nitrogen. 図２３はナノペースト（Ｐ２２）の空気中焼成における熱解析図である。FIG. 23 is a thermal analysis diagram in the air firing of the nanopaste (P22). 図２４はナノペースト（Ｐ２２）の窒素中焼成における熱解析図である。FIG. 24 is a thermal analysis diagram in baking of the nanopaste (P22) in nitrogen. 図２５はナノペースト（Ｐ２３）の空気中焼成における熱解析図である。FIG. 25 is a thermal analysis diagram of the nanopaste (P23) in air firing. 図２６はナノペースト（Ｐ２３）の窒素中焼成における熱解析図である。FIG. 26 is a thermal analysis diagram in the firing of the nanopaste (P23) in nitrogen. 図２７はナノペースト（Ｐ２０－２、Ｐ２１、Ｐ２３）の窒素中・空気中焼成におけるＴＧ熱解析比較図である。FIG. 27 is a comparison diagram of TG thermal analysis of nano pastes (P20-2, P21, P23) in nitrogen and air firing. 図２８は接合試験用のダイオード樹脂モールド体の作製工程図である。FIG. 28 is a production process diagram of a diode resin mold for a bonding test. 図２９はダイオード樹脂モールド体のＶＦ、ΔＶＦの接合試験測定図である。FIG. 29 is a bonding test measurement diagram of VF and ΔVF of the diode resin molded body. 図３０は各種ペーストの大気中・窒素中焼成におけるＶＦの比較図である。FIG. 30 is a comparison diagram of VF when various pastes are fired in air and nitrogen. 図３１は各種ペーストの大気中・窒素中焼成におけるΔＶＦの比較図である。FIG. 31 is a comparative diagram of ΔVF when various pastes are fired in air and nitrogen. 図３２は各種ペーストの大気中焼成における初期・リフロー耐熱試験後のＶＦの比較図である。FIG. 32 is a comparison diagram of VF after the initial reflow heat test in the firing of various pastes in the air. 図３３は各種ペーストの大気中焼成における初期・リフロー耐熱試験後のΔＶＦの比較図である。FIG. 33 is a comparative diagram of ΔVF after the initial reflow heat test in the air firing of various pastes. 図３４は各種ペーストの窒素中焼成における初期・リフロー耐熱試験後のＶＦの比較図である。FIG. 34 is a comparison diagram of VF after the initial reflow heat test in firing various pastes in nitrogen. 図３５は各種ペーストの窒素中焼成における初期・リフロー耐熱試験後のΔＶＦの比較図である。FIG. 35 is a comparative view of ΔVF after the initial and reflow heat test in firing various pastes in nitrogen.
符号の説明Explanation of symbols
　１・・・・ダイオード組立体
　２・・・・リードフレーム
　４・・・・リードフレーム
　６・・・・複合銀ナノペート層
　６ａ・・・銀導体層
　８・・・・ダイオードチップ
　１０・・・複合銀ナノペート層
　１０ａ・・銀導体層
　１２・・・複合銀ナノペート層
　１２ａ・・銀導体層
　１４・・・接続端子
　１６・・・電気炉
　１８・・・ダイオード樹脂モールド体
　２０・・・樹脂モールド
　２２・・・アノード
　２４・・・カソード
　２６・・・直流電源
　２８・・・電流計
　ＶＦ・・・順方向電圧
　ΔＶＦ・・順方向電圧差 DESCRIPTION OF SYMBOLS 1 ... Diode assembly 2 ... Lead frame 4 ... Lead frame 6 ... Composite silver nanopate layer 6a ... Silver conductor layer 8 ... Diode chip 10 ... Composite Silver nanopate layer 10a ... Silver conductor layer 12 ... Composite silver nanopate layer 12a ... Silver conductor layer 14 ... Connection terminal 16 ... Electric furnace 18 ... Diode resin mold body 20 ... Resin mold 22 ... Anode 24 ... Cathode 26 ... DC power supply 28 ... Ammeter VF ... Forward voltage ΔVF ·· Forward voltage difference
　以下、本発明に係る複合銀ナノペースト、その製法及びナノペースト接合方法の実施形態を図面及び表により詳細に説明する。 Hereinafter, embodiments of a composite silver nanopaste, a manufacturing method thereof, and a nanopaste bonding method according to the present invention will be described in detail with reference to the drawings and tables.
　表１は、本発明に使用される複合銀ナノ粒子の製造原料の一覧表である。銀原料として炭酸銀（Ａｇ２ＣＯ３）、アルコール原料としてデカノール（Ｃ１０Ｈ２１ＯＨ）及びドデカノール（Ｃ１２Ｈ２５ＯＨ）が使用される。アルコールの分子量、沸点及び融点は表示される通りである。 Table 1 is a list of raw materials for producing composite silver nanoparticles used in the present invention. Silver carbonate (Ag2CO3) is used as the silver raw material, and decanol (C10H21OH) and dodecanol (C12H25OH) are used as the alcohol raw material. The molecular weight, boiling point and melting point of the alcohol are as indicated.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
　図１は複合銀ナノ粒子の製造工程図である。所定量のＡｇ２ＣＯ３粉体と所定量のアルコールの混合液を調製し、前記混合液を反応容器に封入する。Ａｒガスフロー下で生成温度Ｔ（℃）にて所定時間だけ前記混合液を加熱する。この加熱過程で炭酸銀とアルコールが反応して無数の複合銀ナノ粒子が生成される。反応時間は１時間以内がよく、長時間になると複合銀ナノ粒子が相互に凝集を始めて２次粒子化するので、反応後は急速に冷却することが望ましい。最後に、反応液から複合銀ナノ粒子を粉体として回収する。前記複合銀ナノ粒子をＣｎＡｇＡＬと表示し、銀アルコラート型複合銀ナノ粒子であることを示す。但し、用いるアルコールは上記２種であり、ｎ＝１０又は１２である。 FIG. 1 is a production process diagram of composite silver nanoparticles. A mixed solution of a predetermined amount of Ag2CO3 powder and a predetermined amount of alcohol is prepared, and the mixed solution is sealed in a reaction vessel. The mixture is heated at a generation temperature T (° C.) for a predetermined time under an Ar gas flow. During this heating process, silver carbonate and alcohol react to generate countless composite silver nanoparticles. The reaction time is preferably within 1 hour. When the reaction time is long, the composite silver nanoparticles start to aggregate with each other and become secondary particles. Therefore, it is desirable to cool rapidly after the reaction. Finally, the composite silver nanoparticles are recovered from the reaction solution as a powder. The composite silver nanoparticle is expressed as CnAgAL, and indicates that it is a silver alcoholate-type composite silver nanoparticle. However, the alcohol to be used is the above two types, and n = 10 or 12.
　図２は、本発明に係る複合銀ナノ粒子の生成反応の第１工程図である。原料となる無機化合物は式（１）の炭酸銀Ａｇ２ＣＯ３であり、アルコールは式（２）で示されるデカノール（ｎ＝１０）又はドデカノール（ｎ＝１２）である。式（３）のＲｎはアルコールの炭化水素基を示している。炭素数ｎは１０又は１２に限られる。炭酸銀微粒子はアルコール不溶性であるが、アルコールの親水基ＯＨは炭酸銀微粒子の表面と結合しやすい性質を有する。またアルコールの疎水基Ｒｎはアルコール溶媒と親和性が高い。従って、式（４）に示すように、炭酸銀微粒子をアルコール溶媒に分散させると、炭酸銀微粒子表面にアルコールが取巻き、安定な炭酸銀微粒子コロイドが形成される。 FIG. 2 is a first process diagram of the formation reaction of composite silver nanoparticles according to the present invention. The inorganic compound as a raw material is silver carbonate Ag2CO3 of the formula (1), and the alcohol is decanol (n = 10) or dodecanol (n = 12) represented by the formula (2). Rn in the formula (3) represents a hydrocarbon group of alcohol. The carbon number n is limited to 10 or 12. Although the silver carbonate fine particles are insoluble in alcohol, the hydrophilic group OH of the alcohol has a property of easily bonding to the surface of the silver carbonate fine particles. Moreover, the hydrophobic group Rn of alcohol has high affinity with the alcohol solvent. Therefore, as shown in the formula (4), when the silver carbonate fine particles are dispersed in an alcohol solvent, the alcohol surrounds the surface of the silver carbonate fine particles, and a stable silver carbonate fine particle colloid is formed.
　図３は、本発明に係る複合銀ナノ粒子の生成反応の第２工程図である。炭酸銀微粒子表面の炭酸銀はアルコールと反応して、式（５）に示されるように銀化と同時にアルデヒドＲｎ－１ＣＨＯが生成される。また、式（６）に示されるように、アルデヒドが形成されずに、直ちに銀アルコラートＡｇＯＲｎが生成される反応経路も存在する。前記アルデヒドは強力な還元作用を有し、式（７）に示されるように、炭酸銀を還元して、銀化と同時にカルボン酸Ｒｎ－１ＣＯＯＨが形成される。中間生成されたＡｇ、ＡｇＯＲｎ、Ｒｎ－１ＣＯＯＨは、式（８）及び式（９）に示される反応により相互に凝集し、複合銀ナノ粒子としてＡｇｋ＋ｍ（ＯＲｎ）ｍ、Ａｇｋ＋ｍ（ＯＲｎ）ｍＲｎ－１ＣＯＯＨが生成される。これらの複合銀ナノ粒子は式（１０）及び式（１１）に図示されている。前記反応は炭酸銀微粒子の表面反応であり、表面から次第に内部に浸透しながら反応が継続し、中心核となる炭酸銀微粒子は銀核へと転化してゆく。最終的に、式（１０）及び式（１１）に示される複合銀ナノ粒子が生成され、本発明では、この複合銀ナノ粒子をＣｎＡｇＡＬと書く。 FIG. 3 is a second process diagram of a formation reaction of composite silver nanoparticles according to the present invention. Silver carbonate on the surface of the silver carbonate fine particles reacts with alcohol to form aldehyde R n-1 CHO simultaneously with silveration, as shown in formula (5). Further, as shown in the formula (6), there is a reaction route in which silver alcoholate AgOR n is immediately formed without forming an aldehyde. The aldehyde has a strong reducing action, and as shown in formula (7), silver carbonate is reduced to form carboxylic acid R n-1 COOH simultaneously with silveration. The intermediately produced Ag, AgOR n , and R n-1 COOH aggregate with each other by the reactions shown in Formula (8) and Formula (9), and form Ag k + m (OR n ) m , Ag k + m as composite silver nanoparticles. (OR n ) m R n-1 COOH is produced. These composite silver nanoparticles are illustrated in equations (10) and (11). The reaction is a surface reaction of silver carbonate fine particles. The reaction continues while gradually penetrating from the surface into the interior, and the silver carbonate fine particles serving as the central nucleus are converted into silver nuclei. Finally, composite silver nanoparticles represented by formula (10) and formula (11) are produced, and in the present invention, this composite silver nanoparticle is written as CnAgAL.
　図４はＣ１０ＡｇＡＬの高分解能透過電子顕微鏡図である。複合銀ナノ粒子Ｃ１０ＡｇＡＬは１５２℃の反応温度（生成温度）で単分散状態で生成され、その銀核の平均粒径ＤはＤ＝４．５（ｎｍ）で、その平均誤差δＤは１（ｎｍ）であった。銀核には格子像が見られ、その格子間隔から銀単結晶であることが確認された。 FIG. 4 is a high-resolution transmission electron microscope diagram of C10AgAL. The composite silver nanoparticle C10AgAL is produced in a monodispersed state at a reaction temperature (production temperature) of 152 ° C., the average particle diameter D of the silver nuclei is D = 4.5 (nm), and the average error δD is 1 (nm). )Met. A lattice image was observed in the silver nucleus, and it was confirmed that the silver nucleus was a single crystal of silver from the lattice spacing.
　図５はＣ１２ＡｇＡＬの高分解能透過電子顕微鏡図である。複合銀ナノ粒子Ｃ１２ＡｇＡＬは１７３℃の反応温度（生成温度）で単分散状態で生成され、その銀核の粒径ＤはＤ＝４．７（ｎｍ）であった。銀核の回折像から銀核の格子像は（１１１）面であり、銀核内には２０面が見られるから、銀単結晶の格子間隔ｄ１１１＝０．２３５（ｎｍ）を用いて、前記４．７（ｎｍ）が導出された。 FIG. 5 is a high-resolution transmission electron microscope view of C12AgAL. The composite silver nanoparticle C12AgAL was produced in a monodispersed state at a reaction temperature (production temperature) of 173 ° C., and the particle size D of the silver nucleus was D = 4.7 (nm). From the diffraction image of silver nuclei, the lattice image of silver nuclei is the (111) plane, and 20 planes are seen in the silver nuclei, so using the lattice spacing d 111 = 0.235 (nm) of the silver single crystal, The 4.7 (nm) was derived.
　図６は銀粒子の粒径と融点の関係図である。この関係図は、Ph. Buffat and J-P. Borel, Phy. Rev. A13(1976)2287（非特許文献１）から抜粋されたものである。銀粒子の粒径が小さくなるほど融点は急速に低下し、粒径が５（ｎｍ）で７４０℃、２（ｎｍ）で３６５℃になる。この論文の融点とは銀粒子が完全に融解する温度である。一方、本発明における焼成温度は銀核の焼結温度であるから、銀核の表面融解であり、銀核の完全融解を意味しない。何故なら、銀膜を形成する焼結とは、銀核の表面が融解して銀核相互が結合して銀膜を一体形成することを云い、表面融解温度は前記完全融解温度よりもかなり低くなることは明らかである。従って、後述する平均粒径５（ｎｍ）の複合銀ナノ粒子の金属化温度Ｔ３（℃）は２００～３００℃である。 FIG. 6 is a graph showing the relationship between the silver particle size and the melting point. This relationship diagram is excerpted from Ph. Buffat and J-P. Borel, Phy. Rev. A13 (1976) 2287 (Non-patent Document 1). The melting point rapidly decreases as the particle size of the silver particles decreases, and reaches 740 ° C. when the particle size is 5 (nm) and 365 ° C. when the particle size is 2 (nm). The melting point in this paper is the temperature at which the silver particles melt completely. On the other hand, since the firing temperature in the present invention is the sintering temperature of silver nuclei, it is surface melting of silver nuclei and does not mean complete melting of silver nuclei. This is because sintering to form a silver film means that the surface of silver nuclei is melted and silver nuclei are bonded together to form a silver film integrally. The surface melting temperature is much lower than the complete melting temperature. Obviously. Therefore, the metallization temperature T3 (° C.) of composite silver nanoparticles having an average particle size of 5 (nm), which will be described later, is 200 to 300 ° C.
　表２は、本発明に使用された複合銀ナノ粒子の種類と物性の一覧表である。Ｃ１０ＡｇＡＬは生成温度Ｔが１２０℃で、生成時間が２２分と短時間で生成された。ＤＴＡピーク温度Ｔ２（℃）は発熱反応を開始した後に出現する最終的な反応ピークの温度であり、分解温度とも称され、有機物が強力に気散されている温度を云う。金属化温度Ｔ３（℃）は前記分解が終了して反応ピークが消失する温度であり、銀核が露出する温度でもある。ＤＴＡピーク温度Ｔ２（分解温度）が低いほど、金属化温度Ｔ３も相対的に低くなることが示されている。 Table 2 is a list of types and physical properties of the composite silver nanoparticles used in the present invention. C10AgAL was produced with a production temperature T of 120 ° C. and a production time of 22 minutes. The DTA peak temperature T2 (° C.) is the temperature of the final reaction peak that appears after the exothermic reaction is started, and is also referred to as a decomposition temperature, which is a temperature at which organic substances are strongly diffused. The metallization temperature T3 (° C.) is a temperature at which the decomposition ends and the reaction peak disappears, and is also a temperature at which silver nuclei are exposed. It is shown that the lower the DTA peak temperature T2 (decomposition temperature), the lower the metallization temperature T3.
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000002
　図７は、Ｃ１２ＡｇＡＬの空気中及び窒素ガス中の熱解析図である。空気中のＤＴＡでは、分解温度Ｔ２＝１４６℃の位置に最大ピークがあり、段部を経て金属化温度Ｔ３＝２００℃で一定値に到達している。これに対し、窒素中のＤＴＡでは、急峻な発熱ピークは見られず、緩慢な段部を経て約２２０℃で一定値に到達し、この２２０℃が金属化温度Ｔ３であると考えられる。他方、重量曲線を示す空気中のＴＧは、窒素中のＴＧよりも早く一定値に降下している。複合銀ナノ粒子からアルコラート基が次第に気散し、有機物の全量が気散した段階でＴＧは一定値に到達する。一定値になった温度が金属化温度Ｔ３であるが、この温度はＤＴＡが一定値になった温度と一致するはずであるが、ＴＧを拡大して判断することが重要である。 FIG. 7 is a thermal analysis diagram of C12AgAL in air and nitrogen gas. In DTA in the air, there is a maximum peak at the position of decomposition temperature T2 = 146 ° C., and it reaches a constant value at the metallization temperature T3 = 200 ° C. through the stepped portion. On the other hand, with DTA in nitrogen, a sharp exothermic peak is not observed, and a constant value is reached at about 220 ° C. through a slow step, which is considered to be the metallization temperature T3. On the other hand, the TG in the air showing the weight curve drops to a constant value earlier than the TG in nitrogen. The alcoholate group gradually diffuses from the composite silver nanoparticles, and the TG reaches a constant value when the entire amount of the organic matter is diffused. The temperature at which the constant value has been reached is the metallization temperature T3. This temperature should coincide with the temperature at which the DTA has reached a constant value, but it is important to determine by expanding TG.
　図８は複合銀ナノペーストの製造工程図である。所定重量％の複合銀ナノ粒子ＣｎＡｇＡＬ粉体と、所定重量％の銀微粒子Ａｇ粉体と、所定重量％の樹脂を用意し、これら３成分を混合容器に投入する。混合容器内で例えば４０℃に加熱して樹脂を流動化させ、ペーストを均一混合する。このとき、７００ｒｐｍの自転と２０００ｒｐｍの公転を行う自転公転型の遠心器を利用した。４０℃位の加熱温度であれば、摩擦熱により自然に昇温するから、強制加熱操作は不要である。しかし、４０℃以上になるとヒーター加熱すると効率的に流動化できる。その後、複合銀ナノペーストを急速に冷却し、固形化して回収する・固形化により、均一に分散した複合銀ナノ粒子と銀微粒子が樹脂により固定化され、保管中に凝集することは無い。 FIG. 8 is a production process diagram of composite silver nanopaste. A predetermined weight percent of composite silver nanoparticle CnAgAL powder, a predetermined weight percent of silver fine particle Ag powder, and a predetermined weight percent of resin are prepared, and these three components are put into a mixing container. For example, the resin is fluidized by heating to 40 ° C. in a mixing container, and the paste is uniformly mixed. At this time, a rotation-revolution centrifuge that performs rotation at 700 rpm and revolution at 2000 rpm was used. If the heating temperature is about 40 ° C., the temperature is naturally raised by frictional heat, and therefore a forced heating operation is unnecessary. However, when it is 40 ° C. or higher, it can be efficiently fluidized by heating with a heater. Thereafter, the composite silver nanopaste is rapidly cooled and solidified and recovered. By solidification, the uniformly dispersed composite silver nanoparticles and silver fine particles are fixed by the resin and do not aggregate during storage.
　図８の製造工程を変形した方法も採用される。まず、所定重量％の複合銀ナノ粒子ＣｎＡｇＡＬ粉体と所定重量％の樹脂を加熱しながら混合してペースト中間体を製造する。このペースト中間体に所定重量％の銀微粒子Ａｇ粉体を加熱しながら均一混合して複合銀ナノペーストを製造し、急速冷却して固形化する。摩擦熱を利用する場合には、強制加熱は不要である。この製造法では、まず樹脂中に複合銀ナノ粒子を均一分散させ、その次に銀微粒子を均一分散させるから、複合銀ナノ粒子と銀微粒子が独立に分散され、両者の相互作用を無くすため均一分散性が一層に増大する特徴がある。
　また、他の変形例として、まず所定重量％の銀微粒子Ａｇ粉体と所定重量％の樹脂を加熱しながら混合してペースト中間体を製造する。このペースト中間体に所定重量％の複合銀ナノ粒子ＣｎＡｇＡＬ粉体を加熱しながら均一混合して複合銀ナノペーストを製造し、急速冷却して固形化する。摩擦熱を利用する場合には、強制加熱は不要である。この変形製造法では、まず樹脂中に銀微粒子を均一分散させ、その次に複合銀ナノ粒子を均一分散させるから、複合銀ナノ粒子と銀微粒子が独立に分散され、両者の相互作用を無くすため均一分散性が一層に増大する。 A method in which the manufacturing process of FIG. 8 is modified is also adopted. First, a paste intermediate is produced by mixing a predetermined weight% of composite silver nanoparticles CnAgAL powder and a predetermined weight% of resin while heating. A predetermined weight percent of silver fine particle Ag powder is uniformly mixed with this paste intermediate while heating to produce a composite silver nanopaste, which is rapidly cooled to solidify. When using frictional heat, forced heating is not necessary. In this manufacturing method, the composite silver nanoparticles are uniformly dispersed in the resin, and then the silver fine particles are uniformly dispersed. Therefore, the composite silver nanoparticles and the silver fine particles are dispersed independently, and uniform to eliminate the interaction between the two. It is characterized by further increasing dispersibility.
As another modification, first, a paste intermediate is produced by mixing a predetermined weight% of silver fine particle Ag powder and a predetermined weight% of resin while heating. A predetermined weight percent of composite silver nanoparticle CnAgAL powder is uniformly mixed with this paste intermediate while heating to produce a composite silver nanopaste, which is rapidly cooled to solidify. When using frictional heat, forced heating is not necessary. In this modified manufacturing method, the silver fine particles are first uniformly dispersed in the resin, and then the composite silver nanoparticles are uniformly dispersed. Therefore, the composite silver nanoparticles and the silver fine particles are independently dispersed to eliminate the interaction between the two. Uniform dispersibility is further increased.
　表３は本発明に使用される樹脂の例示表である。イソボルニルシクロヘキサノール（ＩＢＣＨ）は、いわゆる松脂状であり、室温では流動性が無く、加熱により急速に流動化する性質を有する。グリセリンはＩＣＢＨよりも粘性が小さく、いわゆるシロップ状である。グリセリンは冷蔵庫温度以下まで冷却すれば殆んど流動性を消失し、加熱すると流動化するから、前記ＩＢＣＨと同様に本発明の樹脂として使用できる。その他、３０℃以下の室温で固体状であり、例えば４０℃以上になると液化する性質を有し、焼成すると完全に気散する物質も本発明の樹脂として使用できる。例えば、Ｃ数が１４以上の高級アルコールが利用でき、ミリスチルアルコール、パルミチルアルコール、ステアリルアルコール、ベヘニルアルコールなどが列挙される。それらの融点は表３に示す通りである。 Table 3 is an exemplary table of resins used in the present invention. Isobornylcyclohexanol (IBCH) is a so-called rosin-like, has no fluidity at room temperature, and has a property of fluidizing rapidly by heating. Glycerin is less viscous than ICBH and is in the form of a so-called syrup. Glycerin almost loses its fluidity when cooled to a refrigerator temperature or lower, and fluidizes when heated, so that it can be used as the resin of the present invention in the same manner as IBCH. In addition, a substance that is solid at room temperature of 30 ° C. or lower, has a property of being liquefied when heated to 40 ° C. or higher, and completely dissipates when fired can be used as the resin of the present invention. For example, higher alcohols having 14 or more carbon atoms can be used, and myristyl alcohol, palmityl alcohol, stearyl alcohol, behenyl alcohol and the like are listed. Their melting points are as shown in Table 3.
Figure JPOXMLDOC01-appb-T000003
Figure JPOXMLDOC01-appb-T000003
　表４はＩＢＣＨの粘度と温度の関係表である。３０℃以下では１５万センチポイズ（ｃＰ）であるから流動性は無いが、４０℃以上、特に５０℃以上になると急速に流動性を発現するようになり、本発明に最適の樹脂である。 Table 4 is a relationship table between viscosity and temperature of IBCH. Since it is 150,000 centipoise (cP) at 30 ° C. or lower, it does not have fluidity, but when it is 40 ° C. or higher, particularly 50 ° C. or higher, fluidity is rapidly developed, and it is an optimal resin for the present invention.
Figure JPOXMLDOC01-appb-T000004
Figure JPOXMLDOC01-appb-T000004
　図９は、ＩＢＣＨ樹脂の粘度と温度の特性図である。表４に示された粘度の温度に対する関係をプロットしたもので、ＩＢＣＨ樹脂は粘度が対数軸で表示されるほど急激に温度に関して変化する性質を有していることが分かる。このような性質を有し、且つ焼成により全てが気散する性質を有する全ての樹脂が本発明に利用できる。 FIG. 9 is a characteristic diagram of viscosity and temperature of IBCH resin. The relationship between the viscosity and the temperature shown in Table 4 is plotted, and it can be seen that the IBCH resin has a property of rapidly changing with respect to temperature as the viscosity is displayed on a logarithmic axis. All resins having such properties and having the property of being completely diffused by firing can be used in the present invention.
　図１０は、昇温率３℃／ｍｉｎのＩＢＣＨ樹脂の熱解析図である。ＤＴＡから完全蒸発温度は２０５℃であり、ＴＧから２０５℃で重量がゼロ％になっていることが分かり、全量が蒸発して消失したことが証明されている。 FIG. 10 is a thermal analysis diagram of IBCH resin with a temperature increase rate of 3 ° C./min. From DTA, the complete evaporation temperature is 205 ° C., and from TG, the weight is found to be 0% at 205 ° C., and it is proved that the entire amount has evaporated and disappeared.
　表５はＩＣＢＨ樹脂の昇温率と蒸発温度の関係表である。昇温率３（℃／ｍｉｎ）とは１分間に３℃上昇させながら昇温させてゆくプログラム昇温を意味する。昇温率が小さいほど蒸発温度は低くなり、昇温率が大きくなると蒸発温度が高くなる性質がある。本発明の複合銀ナノペーストを焼成する場合、まず樹脂を先に気散させる場合には、昇温率を小さく設定し、樹脂が完全に蒸発した後にアルコラート基を気散させることになる。逆に、まずアルコラート基を先に気散させる場合には、昇温率を大きく設定すればよく、その後に樹脂が完全蒸発することになる。通常は樹脂を完全蒸発させた後に、アルコラート基を気散させる方法が採用される。 Table 5 is a relationship table between the temperature rising rate of ICBH resin and the evaporation temperature. A temperature increase rate of 3 (° C./min) means a program temperature increase in which the temperature is increased while increasing by 3 ° C. per minute. The evaporation temperature decreases as the temperature increase rate decreases, and the evaporation temperature increases as the temperature increase rate increases. When the composite silver nanopaste of the present invention is baked, when the resin is first diffused, the rate of temperature increase is set small, and the alcoholate group is diffused after the resin is completely evaporated. On the other hand, when the alcoholate group is first diffused, the rate of temperature rise should be set large, and then the resin will completely evaporate. Usually, after the resin is completely evaporated, a method in which alcoholate groups are diffused is employed.
Figure JPOXMLDOC01-appb-T000005
Figure JPOXMLDOC01-appb-T000005
　図１１は、ＩＢＣＨ樹脂の蒸発温度と昇温率の関係図である。表５に示された蒸発温度と昇温率の関係をプロットしたものである。このグラフに基づいて、昇温率を調整して蒸発温度を任意に調節することができる。 FIG. 11 is a graph showing the relationship between the evaporation temperature of the IBCH resin and the temperature rise rate. The relationship between the evaporation temperature shown in Table 5 and the temperature increase rate is plotted. Based on this graph, the evaporation rate can be arbitrarily adjusted by adjusting the temperature increase rate.
　表６はグリセリンの粘度と温度の関係表である。０℃では１２１００センチポイズ（ｃＰ）であり、更に冷却すると粘度は急速に増加し非流動状態に容易になる。他方、温度を１０℃以上にすると粘度は３９００（ｃＰ）以下になり、流動性を示すようになる。ＩＢＣＨがやや高い温度の樹脂特性を示すのに対し、グリセリンは低い温度での樹脂特性を示す樹脂であり、両者を適当に使い分けることにより、非流動性・流動性変化を実現できる。前述したように、非流動性とは複合銀ナノ粒子の非凝集性を意味する。 Table 6 is a relationship table between viscosity and temperature of glycerin. At 0 ° C., it is 12100 centipoise (cP), and upon further cooling, the viscosity increases rapidly and facilitates a non-flowing state. On the other hand, when the temperature is set to 10 ° C. or higher, the viscosity becomes 3900 (cP) or lower and exhibits fluidity. While IBCH exhibits a slightly high temperature resin characteristic, glycerin is a resin that exhibits a low temperature resin characteristic, and by appropriately using both, non-fluidity / fluidity change can be realized. As described above, non-fluidity means non-aggregation of composite silver nanoparticles.
Figure JPOXMLDOC01-appb-T000006
Figure JPOXMLDOC01-appb-T000006
　図１２は、グリセリン樹脂の粘度と温度の特性図である。表６に示された粘度の温度に対する関係をプロットしたもので、グリセリン樹脂も粘度が対数軸で表示されるほど急激に温度に関して変化する性質を有していることが分かる。このような性質を有し、且つ焼成により全てが気散する性質を有する全ての樹脂が本発明に利用できる。 FIG. 12 is a characteristic diagram of viscosity and temperature of glycerin resin. The relationship between the viscosity and the temperature shown in Table 6 is plotted, and it can be seen that the glycerin resin also has a property of rapidly changing with respect to temperature as the viscosity is displayed on the logarithmic axis. All resins having such properties and having the property of being completely diffused by firing can be used in the present invention.
　表７は、本発明の接合試験に使用した各種の複合銀ナノペーストの一覧表である。ペースト番号は、Ｐ５、Ｐ１２、Ｐ１２－６、Ｐ１６、Ｐ１７、Ｐ１９、Ｐ２０、Ｐ２０－２、Ｐ２１、Ｐ２２、Ｐ２３の１１種類であり、成分の割合が異なっている。複合銀ナノペーストの成分は、複合銀ナノ粒子ＣｎＡｇＡＬ、銀微粒子Ａｇ、樹脂、溶剤であり、溶剤が添加された複合銀ナノペーストはＰ１９だけである。各成分の添加量は重量％（ｗｔ％）で示されており、合計１００ｗｔ％である。複合銀ナノペーストの全量を１００（ｗｔ％）としたとき、複合銀ナノ粒子の銀核及び銀微粒子からなる銀含有率が最右欄に示されており、残量（記載せず）は有機物、即ち、有機被覆層を構成するアルコラート基と樹脂の含有率を示す。 Table 7 is a list of various composite silver nanopastes used in the joining test of the present invention. There are 11 types of paste numbers: P5, P12, P12-6, P16, P17, P19, P20, P20-2, P21, P22, and P23, and the proportions of the components are different. The components of the composite silver nanopaste are composite silver nanoparticle CnAgAL, silver fine particle Ag, resin, and solvent, and the composite silver nanopaste to which the solvent is added is only P19. The addition amount of each component is shown by weight% (wt%) and is 100 wt% in total. When the total amount of the composite silver nanopaste is 100 (wt%), the silver content of the silver core and silver fine particles of the composite silver nanoparticle is shown in the rightmost column, and the remaining amount (not shown) is an organic matter. That is, the content of the alcoholate group and the resin constituting the organic coating layer is shown.
Figure JPOXMLDOC01-appb-T000007
Figure JPOXMLDOC01-appb-T000007
　Ｐ５～Ｐ１９までのペーストは、複合銀ナノ粒子の重量が３５．７～８３．３（ｗｔ％）と高く、その結果、銀微粒子の重量が３３．３～５３．６（ｗｔ％）と比較的低く調製されている。その中でも、Ｐ１２とＰ１７は銀微粒子を含有せず、複合銀ナノ粒子と樹脂だけから構成され、その分だけ価格的に高い。詳細は後述するが、このグループのペースト特性の結果は、銀含有率が８０％以下では基板との接合面積割合は比較的低くなり、しかも電気伝導度が低下し、熱伝導性も低下することが分かった。また、複合銀ナノ粒子の重量％が高くなると、焼成後の銀膜にボイド（気泡空洞）が多数発生し、電気伝導度が低く（逆に、電気抵抗率が高く）なる傾向がある。 The paste from P5 to P19 has a high composite silver nanoparticle weight of 35.7 to 83.3 (wt%), and as a result, the weight of silver fine particles is compared with 33.3 to 53.6 (wt%). Low. Among them, P12 and P17 do not contain silver fine particles, but are composed only of composite silver nanoparticles and a resin, and are accordingly expensive. Although details will be described later, the results of the paste characteristics of this group show that when the silver content is 80% or less, the bonding area ratio with the substrate is relatively low, and the electrical conductivity and thermal conductivity are also reduced. I understood. Further, when the weight percentage of the composite silver nanoparticles is increased, many voids (bubble cavities) are generated in the fired silver film, and the electrical conductivity tends to be low (in contrast, the electrical resistivity is high).
　本発明者等は、現在の時点で、接合面積割合Ｓ（％）が７０（％）以上であれば接合に使用できると考えている。勿論、接合面積割合Ｓ（％）は７０（％）より高ければ高いほど良いのであるが、判定基準として、Ｓ＜７０を不可（×）、７０≦Ｓ＜８５を可（△）、８５≦Ｓ＜９０を良（○）、９０≦Ｓを優（◎）を設けた。その中でも、良好な複合銀ナノペーストを選択するため、Ｓ≧８５（◎及び○）の範囲を狙って下記の議論を進める。銀含有率が８０（ｗｔ％）を超えるとＰ１２－６は接合面積割合が８３．１％であり、接合面積割合が８５％以上の条件からはずれる。従って、このグループの中で残ったのは、Ｐ１６とＰ１９の種類だけであった。しかし、この２種類も後述するＶＦ試験（電気導通性試験）及びΔＶＦ試験（熱伝導性試験）で良くなかった。従って、複合銀ナノ粒子の重量が３０（ｗｔ％）を超えると、総合特性でよくないことが分かった。つまり、複合銀ナノ粒子の重量が３０（ｗｔ％）を超えるグループでは、接合面積割合が８５％以上であっても、総合特性が良くないという結論である。この結果から、複合銀ナノ粒子が多いと、焼成後の銀膜中にボイドが多数存在し、それが銀膜の機械的・電気的・熱伝導的特性を低下させることが分かった。接合面にボイドが少なければ接合面積割合は高くなるが、銀膜中の内部に存在する微小ボイドは接合面積割合には直接関係しない。従って、接合面積割合が８５％以上と好成績であっても、銀膜内部に無数の微小ボイドが存在すれば、ダイオードにおけるＶＦ試験及びΔＶＦ試験特性が低下し、不合格となることが分かった。 The present inventors believe that at the present time, if the bonding area ratio S (%) is 70 (%) or more, it can be used for bonding. Of course, it is better that the bonding area ratio S (%) is higher than 70 (%), but as a criterion, S <70 is not possible (×), 70 ≦ S <85 is possible (Δ), 85 ≦ S <90 is provided as good (◯), and 90 ≦ S is provided as excellent (◎). Among them, in order to select a good composite silver nanopaste, the following discussion is advanced aiming at a range of S ≧ 85 (◎ and ○). When the silver content exceeds 80 (wt%), P12-6 has a bonding area ratio of 83.1%, which deviates from the condition that the bonding area ratio is 85% or more. Therefore, only P16 and P19 types remained in this group. However, these two types were also not good in the VF test (electrical conductivity test) and ΔVF test (thermal conductivity test) described later. Therefore, it was found that when the weight of the composite silver nanoparticles exceeds 30 (wt%), the overall characteristics are not good. That is, in the group where the weight of the composite silver nanoparticles exceeds 30 (wt%), the conclusion is that the overall characteristics are not good even if the bonding area ratio is 85% or more. From this result, it was found that when the composite silver nanoparticles are large, a large number of voids are present in the fired silver film, which deteriorates the mechanical, electrical, and thermal conductivity characteristics of the silver film. If there are few voids on the bonding surface, the bonding area ratio is high, but the minute voids present inside the silver film are not directly related to the bonding area ratio. Therefore, it was found that even if the junction area ratio was 85% or more, if there were innumerable microvoids inside the silver film, the VF test and ΔVF test characteristics of the diode were degraded and the test was rejected.
　他方、Ｐ２０、Ｐ２０－２、Ｐ２１、Ｐ２２、Ｐ２３のグループは、接合面積割合、ボイド数の低下、ＶＦ試験、ΔＶＦ試験の全てをクリアすることが分かった。このグループは、複合銀ナノ粒子の重量が５～３０（ｗｔ％）、銀微粒子の重量は６０～９０（ｗｔ％）であり、前記樹脂の重量は１５（ｗｔ％）以下である。複合銀ナノ粒子は銀微粒子の接着剤の作用を有し、３０ｗｔ％以下の少量で良いことが判明した。また、銀微粒子が銀膜の主成分として６０ｗｔ％以上必要になり、銀微粒子間の隙間を複合銀ナノ粒子の銀核が埋めて銀膜を形成する場合が、導体接合の高特性を生じる原因と考えられる。このように、複合銀ナノ粒子の重量％が３０ｗｔ％以下の範囲では、接合面積割合が７０％以上あれば、総合特性が良好になることが分かった。勿論、接合面積割合が８５％以上、特に９０％以上になると、総合特性が更に向上することも分かった。換言すれば、前記３０ｗｔ％以下の範囲では、銀膜内部の微小ボイド数が少なくなる結果、総合特性が良好になるということである。更に、樹脂は１５ｗｔ％以下で十分であり、この量程度で銀微粒子と複合銀ナノ粒子を相互に固定する作用を実現する。これ以上だと、有機分が増えて銀含有率を低下させる原因となる。 On the other hand, it was found that the P20, P20-2, P21, P22, and P23 groups cleared all of the bonding area ratio, the number of voids, the VF test, and the ΔVF test. In this group, the weight of the composite silver nanoparticles is 5 to 30 (wt%), the weight of the silver fine particles is 60 to 90 (wt%), and the weight of the resin is 15 (wt%) or less. It has been found that the composite silver nanoparticles have the action of an adhesive of silver fine particles, and a small amount of 30 wt% or less is sufficient. In addition, when silver fine particles are required to be 60 wt% or more as a main component of the silver film and the silver nuclei of the composite silver nanoparticles fill the gaps between the silver fine particles to form the silver film, the cause of the high characteristics of the conductor junction it is conceivable that. As described above, it was found that when the weight percentage of the composite silver nanoparticles is 30 wt% or less, the overall characteristics are improved when the bonding area ratio is 70% or more. Of course, it has also been found that the overall characteristics are further improved when the bonding area ratio is 85% or more, particularly 90% or more. In other words, in the range of 30 wt% or less, the number of microvoids inside the silver film is reduced, and as a result, the overall characteristics are improved. Further, it is sufficient that the resin is 15 wt% or less, and with this amount, the action of fixing the silver fine particles and the composite silver nanoparticles to each other is realized. If it is more than this, the organic content will increase and the silver content will be reduced.
　Ｐ１９だけ溶剤を添加して粘性を低下させているが、有機分の含有率が増大し、銀含有率の低下を生起するから、余り推奨できない。Ｐ１９以外は、溶剤が添加されず、非流動性ペースト（非凝集性ペーストと言っても良い）を４０℃以上に加熱して流動化させ、試験体に塗着可能にした。ペーストとして保管する場合には、３０℃以下の室温まで急速に冷却させて、銀微粒子と複合銀ナノ粒子を固定し、それらの凝集を防止する。 Although only the P19 solvent is added to reduce the viscosity, it is not highly recommended because the organic content increases and the silver content decreases. Except for P19, no solvent was added, and a non-flowable paste (which may be referred to as a non-aggregating paste) was heated to 40 ° C. or more to be fluidized so that it could be applied to the specimen. When stored as a paste, it is rapidly cooled to a room temperature of 30 ° C. or lower to fix the silver fine particles and the composite silver nanoparticles and prevent their aggregation.
　表８は、溶剤として使用されるアルコールの一覧表である。本発明に使用する複合銀ナノ粒子はＣ１０ＡｇＡＬとＣ１２ＡｇＡＬのアルコラート型複合銀ナノ粒子であり、銀核を取巻く有機被覆層はアルコラート基であり、溶剤としてアルコールを使用した場合には、複合銀ナノ粒子はアルコールに極めて良く溶解する性質を有する。アルコールとしては、メタノール、エタノール、ブタノール、ヘキサノール、オクタノールが使用できる。アルコール以外にも、例えば、アセトン、エーテル、ベンゼン、酢酸エチル、テルピネオール、ジヒドロテルピネオール、ブチルカルビトール、セロソルブ等の有機溶媒が利用できる。 Table 8 is a list of alcohols used as solvents. The composite silver nanoparticles used in the present invention are alcoholate type composite silver nanoparticles of C10AgAL and C12AgAL, the organic coating layer surrounding the silver core is an alcoholate group, and when alcohol is used as a solvent, composite silver nanoparticles are used. Has very good solubility in alcohol. As the alcohol, methanol, ethanol, butanol, hexanol, and octanol can be used. In addition to alcohol, organic solvents such as acetone, ether, benzene, ethyl acetate, terpineol, dihydroterpineol, butyl carbitol, cellosolve and the like can be used.
Figure JPOXMLDOC01-appb-T000008
Figure JPOXMLDOC01-appb-T000008
　前述したように、溶剤の添加は、銀含有率を低下させ、流動性ペースト化した場合には複合銀ナノ粒子や銀微粒子の凝集が生起するから、保管貯蔵中は溶剤の無い非流動性ペーストとし、塗着する直前に溶剤を添加することが推奨される。保存期間が極めて短期間の場合でも、凝集の可能性があるから、塗着直前の溶剤添加が望まれる。また、溶剤を添加する場合でも、添加量は全量の１０ｗｔ％以下が好ましく、５ｗｔ％以下が特に望ましい。 As described above, the addition of a solvent reduces the silver content and causes agglomeration of composite silver nanoparticles and silver fine particles when it is made into a fluid paste, so a non-fluid paste without a solvent during storage and storage. It is recommended to add a solvent just before coating. Even when the storage period is very short, there is a possibility of aggregation, and therefore the addition of a solvent immediately before coating is desired. Even when a solvent is added, the addition amount is preferably 10 wt% or less, and particularly preferably 5 wt% or less of the total amount.
　表９は、複合銀ナノペースト（Ｐ５）の熱解析表である。昇温率（℃／ｍｉｎ）を３、１０、２５、５０の４段階に分けて、夫々のケースで空気中での特性温度をＤＴＡ・ＴＧの熱解析から導出した。昇温率が３（℃／ｍｉｎ）の場合だけ、窒素中で熱解析を行った。特性温度とは下記のＴ１、Ｔ２及びＴ３の総称である。分解開始温度Ｔ１（℃）は、ペーストが発熱反応を開始した温度であり、有機物の酸化分解開始温度である。分解温度Ｔ２（℃）は温度上昇と共に酸化分解が持続するが、その最終段階の最大ピーク温度である。金属化温度Ｔ３（℃）は前記最大ピークを過ぎた後にＤＴＡが一定値化する温度であり、有機物の全量が気散した温度である。表９から分かるように、昇温率が増加するに従って、全ての特性温度は増加する傾向にある。窒素雰囲気（Ｎ２）での熱解析では、分解開始温度Ｔ１、分解温度Ｔ２は明確には出現しないが、最終的な金属化温度Ｔ３は測定できる。窒素中では有機物が酸化されず、酸化分解による発熱反応が無いからＤＴＡには明確な発熱ピークが出現しないと考えられる。有機被覆層を構成するアルコラート基は銀核から分離蒸発し、樹脂も蒸発するから、ＴＧの重量減少は明確に検出でき、金属化温度Ｔ３はＴＧが一定値になる温度と考えればよい。このとき、ＤＴＡにも多少のディップが観察され、このことは後述される。 Table 9 is a thermal analysis table of the composite silver nanopaste (P5). The temperature increase rate (° C./min) was divided into four stages of 3, 10, 25, and 50, and in each case, the characteristic temperature in the air was derived from the thermal analysis of DTA · TG. Only when the rate of temperature increase was 3 (° C./min), thermal analysis was performed in nitrogen. The characteristic temperature is a general term for the following T1, T2, and T3. The decomposition start temperature T1 (° C.) is a temperature at which the paste starts an exothermic reaction, and is an oxidative decomposition start temperature of organic matter. The decomposition temperature T2 (° C.) is the maximum peak temperature in the final stage of oxidative decomposition as the temperature rises. The metallization temperature T3 (° C.) is a temperature at which the DTA becomes a constant value after passing the maximum peak, and is a temperature at which the entire amount of organic matter is diffused. As can be seen from Table 9, all characteristic temperatures tend to increase as the rate of temperature increase increases. In the thermal analysis in a nitrogen atmosphere (N2), the decomposition start temperature T1 and the decomposition temperature T2 do not appear clearly, but the final metallization temperature T3 can be measured. It is considered that a clear exothermic peak does not appear in DTA because organic substances are not oxidized in nitrogen and there is no exothermic reaction due to oxidative decomposition. Since the alcoholate group constituting the organic coating layer separates and evaporates from the silver core and the resin also evaporates, a decrease in the weight of TG can be clearly detected, and the metallization temperature T3 can be considered as a temperature at which TG becomes a constant value. At this time, some dip is also observed in the DTA, which will be described later.
Figure JPOXMLDOC01-appb-T000009
Figure JPOXMLDOC01-appb-T000009
　図１３は複合銀ナノペースト（Ｐ５）の熱解析図である。図１３は表９をグラフにしたもので、横軸は特性温度Ｔ１、Ｔ２、Ｔ３であり、縦軸は温度を示す。Ｐ５ペーストでは、昇温率が同一の場合には、特性温度Ｔ１、Ｔ２、Ｔ３は同一直線に乗ることが分かる。昇温率が前記直線が高温側に平行移動する傾向が見られる。窒素中の熱解析は３（℃／ｍｉｎ）の一点しかないが、３（℃／ｍｉｎ）の場合の直線より低温側にくることが観察される。窒素中では蒸発により有機物が気散するから、酸化気散よりも気散速度が速く、窒素中Ｔ３は空気中Ｔ３よりも小さくなると考えられる。 FIG. 13 is a thermal analysis diagram of the composite silver nanopaste (P5). FIG. 13 is a graph of Table 9. The horizontal axis represents characteristic temperatures T1, T2, and T3, and the vertical axis represents temperature. In the P5 paste, it can be seen that the characteristic temperatures T1, T2, and T3 are on the same straight line when the temperature increase rate is the same. There is a tendency for the temperature rise rate to move parallel to the straight line. The thermal analysis in nitrogen has only one point of 3 (° C./min), but it is observed that the temperature is lower than the straight line in the case of 3 (° C./min). Since organic substances are diffused by evaporation in nitrogen, it is considered that the rate of air diffusion is faster than that of oxidative gas and T3 in nitrogen is smaller than T3 in air.
　表１０は、複合銀ナノペーストの種類と接合面積割合の関係表である。各種ペーストをガラス基板に塗着し、これを焼成して銀膜化し、ガラス基板の裏側から接合面積割合Ｓ（％）を導出して表１０を完成した。Ａｇペーストは銀微粒子だけのペースト、Ｐ１６高温３００℃は３００℃の炉中で焼成、プログラム昇温は図１８で後述するプログラム昇温３００℃、７回とは７回平均、５回とは５回平均、１０回とは１０回平均、剥離面粒子除去・剥離面研磨は字義の通り、ＡｒＧａｓとはアルゴンガス中で焼成、ＤＨ＋及びＤＨ＋＋とはジヒドロテルピネオール溶剤添加、を夫々意味する。 Table 10 is a relationship table between the types of composite silver nanopaste and the bonding area ratio. Various pastes were applied to a glass substrate, and this was baked to form a silver film, and the bonding area ratio S (%) was derived from the back side of the glass substrate to complete Table 10. Ag paste is a paste containing only silver fine particles, P16 high temperature 300 ° C. is fired in a furnace at 300 ° C., program temperature rise is 300 ° C. program temperature described later in FIG. 18, 7 times average is 7 times, 5 times is 5 times The average of 10 times, the average of 10 times, the removal of the peeled surface particles and the removal of the peeled surface are literally ArGas means firing in argon gas, and DH + and DH ++ mean dihydroterpineol solvent addition, respectively.
Figure JPOXMLDOC01-appb-T000010
Figure JPOXMLDOC01-appb-T000010
　表１０の接合面積割合Ｓ（％）において、Ｓ＜７０を不可（×）、７０≦Ｓ＜８５を可（△）、８５≦Ｓ＜９０を良（○）、９０≦Ｓを優（◎）と判定する。接合試験では、特に半導体接合試験では、更に過酷な条件をクリアする必要があるから、優の判定が重要と考えられ、良及び可の領域は捨てられた。その結果、最終的に優と判定されたペーストはＰ１６とＰ１９だけであった。しかし、複合銀ナノ粒子の重量％が３０ｗｔ％以下の範囲になると、Ｓ≧７０（％）でも接合試験をクリアできることが分かっている。 In the bonding area ratio S (%) of Table 10, S <70 is not possible (×), 70 ≦ S <85 is acceptable (Δ), 85 ≦ S <90 is good (◯), and 90 ≦ S is excellent (◎) ). In the junction test, particularly in the semiconductor junction test, it is necessary to clear more severe conditions. Therefore, it was considered that the determination of excellent was important, and the good and acceptable areas were discarded. As a result, P16 and P19 were the only pastes finally determined to be excellent. However, it has been found that when the weight percentage of the composite silver nanoparticles falls within the range of 30 wt% or less, the bonding test can be cleared even when S ≧ 70 (%).
　図１４は、各種ナノペーストの接合面積割合Ｓ（％）とペースト銀含有率（％）の関係図である。表１０に示された各種ペーストに表７で示されたペースト銀含有率を組み合わせて図１４が作成された。最高特性は優であるから、その範囲は、Ｓ≧９０（％）且つペースト銀含有率≧８５（％）の範囲であり、優の領域は斜線で示された領域である。この優の領域に入るペーストは、前述したＰ１６とＰ１９であった。表７を見ると、Ｐ１６の組成重量％は、（複合銀ナノ粒子，銀微粒子，樹脂，溶剤、銀含有率）＝（４０，５２，８，０，９０）である。同様にＰ１９の組成重量％は、（複合銀ナノ粒子，銀微粒子，樹脂，溶剤，銀含有率）＝（３５．７，５３．６，７．１，２．０，８５．７）であった。従って、この段階までの接合試験では、溶剤が微量（０～５ｗｔ％）だけ添加される場合には、優の判定である。 FIG. 14 is a relationship diagram of the bonding area ratio S (%) of various nano pastes and the paste silver content (%). FIG. 14 was created by combining the paste silver contents shown in Table 7 with the various pastes shown in Table 10. Since the highest characteristic is excellent, the range is a range of S ≧ 90 (%) and paste silver content ≧ 85 (%), and the excellent region is a region indicated by hatching. The pastes entering this excellent region were P16 and P19 described above. Referring to Table 7, the composition weight% of P16 is (composite silver nanoparticles, silver fine particles, resin, solvent, silver content) = (40, 52, 8, 0, 90). Similarly, the composition weight percentage of P19 was (composite silver nanoparticles, silver fine particles, resin, solvent, silver content) = (35.7, 53.6, 7.1, 2.0, 85.7). It was. Therefore, in the joining test up to this stage, when only a small amount (0 to 5 wt%) of the solvent is added, the judgment is excellent.
　図１５はナノペースト（Ｐ１２）のガラス面との接合図である。ペースト銀含有率は６６．２％、焼成温度は空気中で３００℃であるが、後述する図１４の３００℃プログラム焼成が行われた。焼成後の銀膜の接合面積割合Ｓは３３．９％であった。接合面積割合が不可の理由は次の通りである。表７から判断すると、Ｐ１２ペーストには銀微粒子が全く含有されず、複合銀ナノ粒子が７３．５ｗｔ％で、樹脂が残量の２６．５ｗｔ％であり、銀含有率が６６．２ｗｔ％である。有機物量は３３．８ｗｔ％と極めて高く、銀膜の全てが複合銀ナノ粒子から来ている。焼成により、有機被覆層を構成する大量のアルコラート基は全て酸化分解されるが、発生する大量のガスが気泡と成り、銀核同士が表面融解してネットワーク状に結合しても、内部に大量の気泡空洞、即ち無数のボイドが発生する。その結果、接合面積割合が３３．９％と低下したのである。この事実は、銀成分が複合銀ナノ粒子だけのペーストでは良くないことを意味する。 FIG. 15 is a joint diagram of the nanopaste (P12) with the glass surface. The paste silver content was 66.2% and the firing temperature was 300 ° C. in the air, but the 300 ° C. program firing of FIG. 14 described later was performed. The bonded area ratio S of the silver film after firing was 33.9%. The reason why the bonding area ratio is not possible is as follows. Judging from Table 7, the P12 paste does not contain any silver fine particles, the composite silver nanoparticles are 73.5 wt%, the resin is 26.5 wt% of the remaining amount, and the silver content is 66.2 wt%. is there. The amount of organic matter is as extremely high as 33.8 wt%, and the entire silver film is made of composite silver nanoparticles. Although a large amount of alcoholate groups constituting the organic coating layer are all oxidatively decomposed by firing, a large amount of generated gas becomes bubbles, and even if silver nuclei are melted on the surface and bonded in a network, a large amount inside Bubble voids, that is, innumerable voids. As a result, the bonding area ratio decreased to 33.9%. This fact means that the silver component is not good for a paste containing only composite silver nanoparticles.
　図１６はナノペースト（Ｐ１６）のＣｕ面との接合図である。ペースト銀含有率は９０％、焼成温度は空気中で３０分間、３００℃であるが、プログラム焼成は行われていない。焼成後の銀膜の接合面積割合Ｓは９５．４％と極めて高くなった。接合面積割合が優の理由は次の通りである。表７から判断すると、Ｐ１６の組成重量％は、（複合銀ナノ粒子，銀微粒子，樹脂，溶剤、銀含有率）＝（４０，５２，８，０，９０）である。Ｐ１６ペーストには粒径０．４μｍの銀微粒子が５２ｗｔ％含有され、複合銀ナノ粒子が４０ｗｔ％であり、銀含有率が９０ｗｔ％で、結果として有機物量は１０ｗｔ％である。まず、有機物量が少ないためにガス発生量が少なくなり、ボイド数が急減される。しかも、複合銀ナノ粒子が銀微粒子同士の隙間を埋めるように集積して銀膜を形成すると考えられ、その結果接合面積割合が９５．４％と極めて高くなったと考えられる。 FIG. 16 is a bonding diagram of the nano paste (P16) with the Cu surface. The paste silver content is 90% and the firing temperature is 300 ° C. in air for 30 minutes, but no program firing is performed. The bonding area ratio S of the silver film after firing was as extremely high as 95.4%. The reason why the bonding area ratio is excellent is as follows. Judging from Table 7, the composition weight% of P16 is (composite silver nanoparticles, silver fine particles, resin, solvent, silver content) = (40, 52, 8, 0, 90). The P16 paste contains 52 wt% of silver fine particles having a particle diameter of 0.4 μm, composite silver nanoparticles are 40 wt%, the silver content is 90 wt%, and the organic matter amount is 10 wt% as a result. First, since the amount of organic matter is small, the amount of gas generated is reduced, and the number of voids is rapidly reduced. Moreover, it is considered that the composite silver nanoparticles are accumulated so as to fill the gaps between the silver fine particles to form a silver film, and as a result, the bonding area ratio is considered to be extremely high at 95.4%.
　図１７はナノペースト（Ｐ１９）の接合図である。ペースト銀含有率は９０％、焼成温度は空気中で３０分間、３００℃であるが、プログラム焼成は行われていない。焼成後の銀膜の接合面積割合Ｓは９５．４％と極めて高くなった。接合面積割合が優の理由は次の通りである。Ｐ１６の組成重量％は、（複合銀ナノ粒子，銀微粒子，樹脂，溶剤、銀含有率）＝（４０，５２，８，０，８７．４）である。Ｐ１６ペーストには粒径０．４μｍの銀微粒子が５２ｗｔ％含有され、複合銀ナノ粒子が４０ｗｔ％であり、銀含有率が８７．４ｗｔ％で、結果として有機物量は１０ｗｔ％である。銀含有率の点で、表７のＰ１６の僅かな差があるが、試作品ごとに多少差異がある。まず、有機物量が少ないためにガス発生量が少なくなり、ボイド数が急減される。しかも、複合銀ナノ粒子が銀微粒子同士の隙間を埋めるように集積して銀膜を形成すると考えられ、その結果接合面積割合が９５．４％と極めて高くなったと考えられる。 FIG. 17 is a joint diagram of nano paste (P19). The paste silver content is 90% and the firing temperature is 300 ° C. in air for 30 minutes, but no program firing is performed. The bonding area ratio S of the silver film after firing was as extremely high as 95.4%. The reason why the bonding area ratio is excellent is as follows. The composition weight percentage of P16 is (composite silver nanoparticles, silver fine particles, resin, solvent, silver content) = (40, 52, 8, 0, 87.4). The P16 paste contains 52 wt% of silver fine particles having a particle size of 0.4 μm, composite silver nanoparticles are 40 wt%, the silver content is 87.4 wt%, and the organic matter amount is 10 wt% as a result. There is a slight difference in P16 in Table 7 in terms of silver content, but there are some differences for each prototype. First, since the amount of organic matter is small, the amount of gas generated is reduced, and the number of voids is rapidly reduced. Moreover, it is considered that the composite silver nanoparticles are accumulated so as to fill the gaps between the silver fine particles to form a silver film, and as a result, the bonding area ratio is considered to be extremely high at 95.4%.
　図１８はペーストでの温度・時間関係図である。図１８には、最高温度が３００℃、２５０℃、２００℃の３種類の昇温プログラムが図示されているが、最高温度を３５０℃、４００℃、４５０℃、５００℃と上昇させることも自在であり、焼成時間も１５分、２０分から更に１時間、２時間と可変することもできる。この焼成昇温プログラムはコンピュータにより制御された電気炉で実現できる。精密に焼成する場合には、コンピュータ制御の昇温プログラムを利用することが好適である。 FIG. 18 is a temperature / time relationship diagram in the paste. FIG. 18 shows three types of temperature raising programs with the maximum temperatures of 300 ° C., 250 ° C., and 200 ° C., but the maximum temperature can be increased to 350 ° C., 400 ° C., 450 ° C., and 500 ° C. The firing time can also be changed from 15 minutes and 20 minutes to 1 hour and 2 hours. This firing temperature raising program can be realized by an electric furnace controlled by a computer. In the case of precise firing, it is preferable to use a computer-controlled temperature raising program.
　表１１は複合銀ナノペーストの種類と接合面積割合及び比抵抗の関係表である。横Ｗ（ｃｍ）及び縦Ｌ（ｃｍ）のガラス板にＰ１２，Ｐ１６、Ｐ１９の３種類のペースト膜を塗着し、３００℃の昇温プログラムにより、１５分間で焼成を行った。その結果、膜厚ｄ（μｍ）の銀膜が形成された。銀膜とガラス板との接合面積割合Ｓ（％）及び銀膜の電気抵抗率ρ（μΩｃｍ）が測定され、表１１の結果が得られた。電気抵抗率ρ（μΩｃｍ）はρ≦１０（μΩｃｍ）のとき、良好な結果が確認され、Ｐ１６とＰ１９のペーストが合格とされた。 Table 11 shows the relationship between the type of composite silver nanopaste, the bonding area ratio, and the specific resistance. Three types of paste films of P12, P16, and P19 were applied to a glass plate having a width W (cm) and a length L (cm), and firing was performed for 15 minutes by a temperature rising program at 300 ° C. As a result, a silver film having a film thickness d (μm) was formed. The bonding area ratio S (%) between the silver film and the glass plate and the electrical resistivity ρ (μΩcm) of the silver film were measured, and the results shown in Table 11 were obtained. When the electrical resistivity ρ (μΩcm) was ρ ≦ 10 (μΩcm), good results were confirmed, and the pastes of P16 and P19 were accepted.
Figure JPOXMLDOC01-appb-T000011
Figure JPOXMLDOC01-appb-T000011
　上述した接合試験においてペーストＰ１６及びＰ１９は、接合面積割合及び電気抵抗率の試験をクリアした。更に、Ｐ１６及びＰ１９について、後述するダイオード試験体に関するＶＦ試験及びΔＶＦ試験が行われた。Ｐ１６及びＰ１９の両者共に、半導体特性試験であるＶＦ試験及びΔＶＦ試験を十分にはクリアできなかった。しかし、Ｐ１６及びＰ１９は基板への電極パターン特性には十分に適用することができることが分かった。 In the bonding test described above, pastes P16 and P19 cleared the bonding area ratio and electrical resistivity tests. Furthermore, with respect to P16 and P19, a VF test and a ΔVF test on a diode test body described later were performed. Both P16 and P19 could not sufficiently clear the VF test and ΔVF test, which are semiconductor characteristic tests. However, it has been found that P16 and P19 can be sufficiently applied to the electrode pattern characteristics on the substrate.
　次に、ＶＦ試験及びΔＶＦ試験をクリアするために、ペーストとしてＰ２０－２、Ｐ２１、Ｐ２２及びＰ２３を用いて実験を継続した。これらのペーストグループと前記Ｐ１６及びＰ１９のグループとは、複合銀ナノ粒子と銀微粒子の添加割合が異なっている。Ｐ２０～Ｐ２３の複合銀ナノ粒子の重量は５～３０（ｗｔ％）と比較的小さくなっており、銀微粒子の重量は６０～９０（ｗｔ％）と比較的大きくなり、しかし銀含有率は８４（ｗｔ％）以上に設定されている。他方、Ｐ１６及びＰ１９の複合銀ナノ粒子の重量は３０（ｗｔ％）以上で、銀微粒子の重量は６０（ｗｔ％）以下に調製され、しかし銀含有率は８５（ｗｔ％）以上である。両グループは銀含有率はほぼ同一範囲であるが、複合銀ナノ粒子の重量範囲と銀微粒子の重量範囲が大きな差異がある。即ち、Ｐ２０～Ｐ２３のペーストは、複合銀ナノ粒子の配合割合を少なくして、その分だけ銀微粒子の配合割合を大きくしている点に特徴を有する。本発明者等の思想は、複合銀ナノ粒子は銀微粒子同士の接着剤の役割を担う点で少なくて良く、銀含有率への寄与は第１が銀微粒子、第２が複合銀ナノ粒子という順番である。 Next, in order to clear the VF test and the ΔVF test, the experiment was continued using P20-2, P21, P22 and P23 as paste. These paste groups and the P16 and P19 groups are different in the addition ratio of the composite silver nanoparticles and the silver fine particles. The composite silver nanoparticles of P20 to P23 have a relatively small weight of 5 to 30 (wt%), the silver fine particles have a relatively large weight of 60 to 90 (wt%), but the silver content is 84 (Wt%) or more is set. On the other hand, the composite silver nanoparticles of P16 and P19 have a weight of 30 (wt%) or more and the silver fine particles have a weight of 60 (wt%) or less, but the silver content is 85 (wt%) or more. Although both groups have almost the same silver content, there is a great difference between the weight range of the composite silver nanoparticles and the weight range of the silver fine particles. That is, the pastes P20 to P23 are characterized in that the compounding ratio of the composite silver nanoparticles is decreased and the compounding ratio of the silver fine particles is increased accordingly. The idea of the present inventors is that the composite silver nanoparticles may be small in that they play the role of an adhesive between the silver fine particles, and the contribution to the silver content rate is that the first is silver fine particles and the second is composite silver nanoparticles. In order.
　複合銀ナノ粒子が銀微粒子同士の接着剤の役割を担う点につき、詳細に説述する。本発明で使用される銀微粒子の粒径は０．１～３．０μｍが好適である。これに対し、複合銀ナノ粒子の銀核の平均粒径は１～２０ｎｍである。大きな銀微粒子間には当然に隙間が空き、緻密な銀膜を形成するには、前記隙間を多数の銀核で埋め、且つ銀微粒子同士を銀核で接合する必要がある。従って、複合銀ナノ粒子の配合割合は、前記隙間を埋める程度で十分であり、本発明者等の計算では、銀微粒子の重量が６０～９０（ｗｔ％）であるのに対し、前記の重量は５～３０（ｗｔ％）でよく、更に好適には８～２０（ｗｔ％）が好適である。この範囲に調整された複合銀ナノ粒子であれば、銀微粒子間の接着性と隙間充填性が保証される。樹脂重量が１５（ｗｔ％）以下であるのは、ペースト保管中の複合銀ナノ粒と銀微粒子の固定性と塗着時の加熱流動性を確保するためである。 The point that the composite silver nanoparticles play the role of an adhesive between the silver particles will be described in detail. The particle size of the silver fine particles used in the present invention is preferably 0.1 to 3.0 μm. On the other hand, the average particle diameter of the silver nuclei of the composite silver nanoparticles is 1 to 20 nm. Naturally, there are gaps between the large silver fine particles, and in order to form a dense silver film, it is necessary to fill the gaps with a large number of silver nuclei and to join the silver fine particles with the silver nuclei. Therefore, the compounding ratio of the composite silver nanoparticles is sufficient to fill the gap. According to calculations by the present inventors, the weight of the silver fine particles is 60 to 90 (wt%), whereas the weight described above is sufficient. May be from 5 to 30 (wt%), more preferably from 8 to 20 (wt%). If the composite silver nanoparticles are adjusted to this range, the adhesion between the silver fine particles and the gap filling property are guaranteed. The reason why the resin weight is 15 (wt%) or less is to secure the fixability of the composite silver nanoparticles and silver fine particles during paste storage and the heat fluidity during coating.
　以下で空気中焼成と窒素中焼成の実験例を説明するが、結果的には窒素中焼成が接合には有利であることが証明された。空気中焼成では、有機物が酸化分解されるため発熱し、この発生熱により銀核が大きな熱振動を生起し、銀微粒子間の隙間に移動し難く、その結果隙間を埋設せずに勝手な位置に留まるため、銀膜中にボイドが多数形成されることが分かった。ボイド形成は電気抵抗率が大きくなり（電気伝導率が小さく）、熱伝導性が小さくなって接合される半導体素子に悪影響を与えやすくなる。しかも、空気中焼成は発熱作用により焼成温度が高くなる弱点を有する。 Hereinafter, experimental examples of firing in air and firing in nitrogen will be described. As a result, it was proved that firing in nitrogen is advantageous for bonding. In firing in air, organic substances are oxidized and decomposed, generating heat, and the generated heat causes silver nuclei to generate large thermal vibrations that are difficult to move into the gaps between the silver fine particles. Therefore, it was found that many voids were formed in the silver film. Void formation increases the electrical resistivity (lower electrical conductivity) and decreases thermal conductivity, which tends to adversely affect the semiconductor elements to be joined. Moreover, firing in air has a weak point in that the firing temperature is increased by an exothermic action.
　以上に対し、窒素中焼成では、有機物が酸化分解されずに蒸発し、蒸発温度は酸化分解温度よりも一般的に低いから、焼成温度を空気中の焼成温度よりも低く出来る利点がある。しかも、吸熱しながら蒸発するから、焼成温度を低くする効果がある。従って、このような低い焼成温度では銀核の熱振動は小さく、銀微粒子間の隙間に自然に移動し、銀膜の緻密化が実現できる。銀膜の緻密化は、高電気伝導性と高熱伝導性を与えるから、後述するＶＦ試験とΔＶＦ試験の両試験をクリアすることが可能になる。また、アルコラート基と樹脂分子は、分解せずにそのまま蒸発するから発生するガスモル量が酸化分解よりも少なく、ガスの抜け孔であるボイド発生量を少なくできる効果がある。 On the other hand, in the firing in nitrogen, the organic substance evaporates without being oxidatively decomposed, and the evaporation temperature is generally lower than the oxidative decomposition temperature. Therefore, there is an advantage that the firing temperature can be lower than the firing temperature in the air. Moreover, since it evaporates while absorbing heat, it has the effect of lowering the firing temperature. Therefore, at such a low firing temperature, the thermal vibration of the silver nuclei is small, and the silver nuclei move naturally into the gaps between the silver fine particles, so that the silver film can be densified. The densification of the silver film provides high electrical conductivity and high thermal conductivity, so that both the VF test and the ΔVF test described later can be cleared. Further, since the alcoholate group and the resin molecule evaporate as they are without being decomposed, the amount of generated gas is less than that of oxidative decomposition, and the amount of voids that are gas escape holes can be reduced.
　図１９はナノペースト（Ｐ２０－２）の空気中焼成における熱解析図である。Ｐ２０－２のペースト１６ｍｇを、室温（ＲＴ）から４００℃まで、昇温率３℃／ｍｉｎで昇温させて熱解析を行った。ＤＴＡにおいて、分解開始温度Ｔ１は１５８℃、最大ピーク温度である分解温度Ｔ２は２３７℃、そして金属化温度Ｔ３は２４９℃であった。ＴＧは１７５℃にくびれがあるが、実際には一定値になる温度は前記Ｔ３と同温度（２３７℃）であった。 FIG. 19 is a thermal analysis diagram of the nanopaste (P20-2) in air firing. Thermal analysis was performed by heating 16 mg of P20-2 paste from room temperature (RT) to 400 ° C. at a rate of temperature increase of 3 ° C./min. In DTA, the decomposition start temperature T1 was 158 ° C., the maximum peak temperature decomposition temperature T2 was 237 ° C., and the metallization temperature T3 was 249 ° C. Although TG has a constriction at 175 ° C., the temperature at which the TG actually becomes a constant value is the same temperature as T3 (237 ° C.).
　図２０はナノペースト（Ｐ２０－２）の窒素中焼成における熱解析図である。Ｐ２０－２のペースト１５ｍｇを、室温（ＲＴ）から４００℃まで、昇温率３℃／ｍｉｎで昇温させて熱解析を行った。ＤＴＡにおいて発熱ピークは見られず、分解開始温度Ｔ１と分解温度Ｔ２は明確でなく、金属化温度Ｔ３は１７３℃であった。ＴＧからも１７３℃がＴ３として得られる。
　図１９と図２０を対比すると、金属化温度は、窒素中焼成では１７３℃、空気中焼成では２４９℃となり、窒素中温度がかなり低くなることが分かった。つまり、窒素中では焼成温度を低く設定できるから、コスト低減に効果がある。また、窒素中の焼成温度を空気中焼成温度と同じくらいに高く設定すれば、生成される銀膜の緻密化は一層改善され、高電気伝導と高熱伝導を保証できる。 FIG. 20 is a thermal analysis diagram of baking of the nanopaste (P20-2) in nitrogen. Thermal analysis was performed by heating 15 mg of P20-2 paste from room temperature (RT) to 400 ° C. at a rate of temperature increase of 3 ° C./min. In DTA, no exothermic peak was observed, the decomposition start temperature T1 and the decomposition temperature T2 were not clear, and the metallization temperature T3 was 173 ° C. From TG, 173 ° C. is obtained as T3.
19 and 20 were compared, it was found that the metallization temperature was 173 ° C. for firing in nitrogen and 249 ° C. for firing in air, and the temperature in nitrogen was considerably low. That is, since the firing temperature can be set low in nitrogen, it is effective in reducing costs. Further, if the firing temperature in nitrogen is set to be as high as the firing temperature in air, the density of the produced silver film can be further improved, and high electrical conduction and high thermal conduction can be guaranteed.
　図２１はナノペースト（Ｐ２１）の空気中焼成における熱解析図である。Ｐ２１のペースト１５ｍｇを、室温（ＲＴ）から４００℃まで、昇温率３℃／ｍｉｎで昇温させて熱解析を行った。ＤＴＡにおいて、分解開始温度Ｔ１は１５２℃、最大ピーク温度である分解温度Ｔ２は２５３℃、そして金属化温度Ｔ３は２７７℃であった。ＴＧは１５８℃にくびれがあるが、実際には緩慢に低減し、一定値になる温度は前記Ｔ３と同温度（２７７℃）であった。 FIG. 21 is a thermal analysis diagram of the nanopaste (P21) in air firing. Thermal analysis was performed by heating 15 mg of P21 paste from room temperature (RT) to 400 ° C. at a rate of temperature increase of 3 ° C./min. In DTA, the decomposition start temperature T1 was 152 ° C., the maximum peak temperature decomposition temperature T2 was 253 ° C., and the metallization temperature T3 was 277 ° C. Although TG has a constriction at 158 ° C., the temperature actually decreased slowly, and the temperature at which it reached a constant value was the same temperature as T3 (277 ° C.).
　図２２はナノペースト（Ｐ２１）の窒素中焼成における熱解析図である。Ｐ２１のペースト１６ｍｇを、室温（ＲＴ）から４００℃まで、昇温率３℃／ｍｉｎで昇温させて熱解析を行った。ＤＴＡにおいて発熱ピークは見られず、分解開始温度Ｔ１と分解温度Ｔ２は明確でなく、金属化温度Ｔ３は１７６℃であった。ＴＧからも１７６℃がＴ３として得られる。
　図２１と図２２を対比すると、金属化温度は、窒素中焼成では１７７℃、空気中焼成では２７７℃となり、窒素中温度がかなり低くなることが分かった。つまり、窒素中では焼成温度を低く設定できるから、コスト低減に効果がある。また、窒素中の焼成温度を空気中焼成温度と同じくらいに高く設定すれば、生成される銀膜の緻密化は一層改善され、高電気伝導と高熱伝導を保証できることが実証された。 FIG. 22 is a thermal analysis diagram in the firing of the nanopaste (P21) in nitrogen. Thermal analysis was performed by heating 16 mg of P21 paste from room temperature (RT) to 400 ° C. at a rate of temperature increase of 3 ° C./min. In DTA, no exothermic peak was observed, decomposition start temperature T1 and decomposition temperature T2 were not clear, and metallization temperature T3 was 176 ° C. From TG, 176 ° C. is obtained as T3.
When FIG. 21 and FIG. 22 are compared, it was found that the metallization temperature was 177 ° C. for firing in nitrogen and 277 ° C. for firing in air, and the temperature in nitrogen was considerably low. That is, since the firing temperature can be set low in nitrogen, it is effective in reducing costs. It was also demonstrated that if the firing temperature in nitrogen is set as high as the firing temperature in air, the density of the resulting silver film can be further improved and high electrical conductivity and high thermal conductivity can be guaranteed.
　図２３はナノペースト（Ｐ２２）の空気中焼成における熱解析図である。Ｐ２２のペースト１５ｍｇを、室温（ＲＴ）から４００℃まで、昇温率１℃／ｍｉｎで昇温させて熱解析を行った。ＤＴＡにおいて、分解開始温度Ｔ１は１２８℃、最大ピーク温度である分解温度Ｔ２は２２０℃、そして金属化温度Ｔ３は２５８℃であった。ＴＧは１４３℃にくびれがあるが、実際には緩慢に低減し、一定値になる温度は前記Ｔ３よりやや低く２３６℃であった。 FIG. 23 is a thermal analysis diagram of the nanopaste (P22) in air firing. Thermal analysis was performed by heating 15 mg of P22 paste from room temperature (RT) to 400 ° C. at a rate of temperature increase of 1 ° C./min. In DTA, the decomposition start temperature T1 was 128 ° C., the maximum peak temperature decomposition temperature T2 was 220 ° C., and the metallization temperature T3 was 258 ° C. Although TG has a constriction at 143 ° C., it actually decreased slowly, and the temperature at which it reached a constant value was 236 ° C., which was slightly lower than T3.
　図２４はナノペースト（Ｐ２２）の窒素中焼成における熱解析図である。Ｐ２２のペースト１５ｍｇを、室温（ＲＴ）から４００℃まで、昇温率１℃／ｍｉｎで昇温させて熱解析を行った。ＤＴＡは図示されず、ＴＧから金属化温度Ｔ３は１５２℃であった。同図に併示される空気中焼成のＴＧでは、前記１５２℃から２３０℃までＴＧが低減することが分かる。つまり、窒素中では金属化しても、空気中ではまだ気散が継続し、金属化には約８０℃ほど昇温する必要がある。
　図２３と図２４を対比すると、金属化温度は、窒素中焼成では１７７℃、空気中焼成では２７７℃となり、窒素中温度がかなり低くなることが分かった。つまり、窒素中では焼成温度を低く設定できる。また、窒素中の焼成温度を空気中焼成温度と同じくらいに高く設定すれば、生成される銀膜の緻密化は一層改善され、高電気伝導と高熱伝導を保証できることが実証された。 FIG. 24 is a thermal analysis diagram in baking of the nanopaste (P22) in nitrogen. Thermal analysis was performed by heating 15 mg of P22 paste from room temperature (RT) to 400 ° C. at a rate of temperature increase of 1 ° C./min. DTA was not shown, and the metallization temperature T3 from the TG was 152 ° C. In the air-fired TG shown together in the figure, it can be seen that the TG decreases from 152 ° C. to 230 ° C. That is, even if metallized in nitrogen, air diffusion still continues in the air, and it is necessary to raise the temperature by about 80 ° C. for metallization.
Comparing FIG. 23 and FIG. 24, it was found that the metallization temperature was 177 ° C. for firing in nitrogen and 277 ° C. for firing in air, and the temperature in nitrogen was considerably low. That is, the firing temperature can be set low in nitrogen. It was also demonstrated that if the firing temperature in nitrogen is set as high as the firing temperature in air, the density of the resulting silver film can be further improved and high electrical conductivity and high thermal conductivity can be guaranteed.
　図２５はナノペースト（Ｐ２３）の空気中焼成における熱解析図である。Ｐ２３のペースト１４ｍｇを、室温（ＲＴ）から４００℃まで、昇温率３℃／ｍｉｎで昇温させて熱解析を行った。ＤＴＡにおいて、分解開始温度Ｔ１は１３０℃、最大ピーク温度である分解温度Ｔ２は２３８℃、そして金属化温度Ｔ３は２６７℃であった。ＴＧは１５８℃にくびれがあるが、実際には緩慢に低減し、一定値になる温度は前記Ｔ３と同温度（２６７℃）であった。 FIG. 25 is a thermal analysis diagram of the nanopaste (P23) in air firing. Thermal analysis was performed by heating 14 mg of P23 paste from room temperature (RT) to 400 ° C. at a rate of temperature increase of 3 ° C./min. In DTA, the decomposition start temperature T1 was 130 ° C., the maximum peak temperature decomposition temperature T2 was 238 ° C., and the metallization temperature T3 was 267 ° C. TG has a constriction at 158 ° C., but actually it slowly decreased, and the temperature at which it reached a constant value was the same temperature as T3 (267 ° C.).
　図２６はナノペースト（Ｐ２３）の窒素中焼成における熱解析図である。Ｐ２３のペースト１４ｍｇを、室温（ＲＴ）から４００℃まで、昇温率３℃／ｍｉｎで昇温させて熱解析を行った。ＤＴＡにおいて発熱ピークは見られず、分解開始温度Ｔ１と分解温度Ｔ２は明確でなく、金属化温度Ｔ３は１７０℃であった。ＴＧからも１７０℃がＴ３として得られる。
　図２５と図２６を対比すると、金属化温度は、窒素中焼成では１７０℃、空気中焼成では２６７℃となり、窒素中温度がかなり低くなることが分かった。つまり、窒素中では焼成温度を低く設定できるから、コスト低減に効果がある。また、窒素中の焼成温度を空気中焼成温度と同じくらいに高く設定すれば、生成される銀膜の緻密化は一層改善され、高電気伝導と高熱伝導を保証できることが実証された。 FIG. 26 is a thermal analysis diagram in the firing of the nanopaste (P23) in nitrogen. Thermal analysis was performed by heating 14 mg of P23 paste from room temperature (RT) to 400 ° C. at a rate of temperature increase of 3 ° C./min. In DTA, no exothermic peak was observed, the decomposition start temperature T1 and the decomposition temperature T2 were not clear, and the metallization temperature T3 was 170 ° C. Also from TG, 170 ° C. is obtained as T3.
25 and 26 were compared, it was found that the metallization temperature was 170 ° C. for firing in nitrogen and 267 ° C. for firing in air, and the temperature in nitrogen was considerably low. That is, since the firing temperature can be set low in nitrogen, it is effective in reducing costs. It was also demonstrated that if the firing temperature in nitrogen is set as high as the firing temperature in air, the density of the resulting silver film can be further improved and high electrical conductivity and high thermal conductivity can be guaranteed.
　図２７はナノペースト（Ｐ２０－２、Ｐ２１、Ｐ２３）の窒素中・空気中焼成におけるＴＧ熱解析比較図である。窒素中焼成ではＴＧが一定値に達しても、空気中焼成ではＴＧがまだ減少を継続することが分かる。明らかに、窒素中焼成では金属化温度Ｔ３が空気中焼成よりも低下することが実証されている。 FIG. 27 is a comparison diagram of TG thermal analysis when nanopastes (P20-2, P21, P23) are fired in nitrogen and in air. It can be seen that even if the TG reaches a certain value in the firing in nitrogen, the TG still continues to decrease in the firing in the air. Clearly, it has been demonstrated that the metallization temperature T3 is lower in the firing in nitrogen than in the air.
　表１２は、Ｐ２０－２、Ｐ２１、Ｐ２２、Ｐ２３の空気中、窒素中の特性温度表である。図１９～図２７で測定された特性温度（Ｔ１、Ｔ２、Ｔ３）が一覧表にされている。Ｐ２２だけが昇温率１℃／ｍｉｎであるが、それ以外のペーストの昇温率は３℃／ｍｉｎである。窒素中焼成の金属化温度Ｔ３は空気中焼成の金属化温度Ｔ３よりもかなり低いことが明白である。但し、窒素中焼成の金属化温度Ｔ３はＴＧから得られたものであり、窒素中の方が低いという事実は明らかである。 Table 12 is a characteristic temperature table in air and nitrogen of P20-2, P21, P22, and P23. The characteristic temperatures (T1, T2, T3) measured in FIGS. 19 to 27 are listed. Only P22 has a temperature increase rate of 1 ° C./min, but the temperature increase rate of other pastes is 3 ° C./min. It is clear that the metallization temperature T3 for firing in nitrogen is considerably lower than the metallization temperature T3 for firing in air. However, the fact that the metallization temperature T3 for firing in nitrogen is obtained from TG, the fact that it is lower in nitrogen is clear.
Figure JPOXMLDOC01-appb-T000012
Figure JPOXMLDOC01-appb-T000012
　図２８は接合試験用のダイオード樹脂モールド体の作製工程図である。（２８Ａ）では、リードフレーム２、４の上に複合銀ナノペースト層６、１２を夫々塗着する。複合銀ナノペースト層６の上にダイオードチップ８を載置し、ダイオードチップ８の上に複合銀ナノペースト層１０を塗着する。最後に、接続端子１４の両端を前記複合銀ナノペースト層１０、１２に載置してダイオード組立体１を完成する。（２８Ｂ）では、前記ダイオード組立体１を電気炉１６の中で焼成し、複合銀ナノペースト層６、１０、１２を銀導体層６ａ、１０ａ、１２ａに変化させる。更に、焼成後の前記ダイオード組立体１を樹脂モールド２０により密封してダイオード樹脂モールド体１８を完成し、このダイオード樹脂モールド体１８を後述するＶＦ試験及びΔＶＦ試験に移行する。左右から突出するリードフレームは電極となるアノード２２とカソード２４になる。 FIG. 28 is a production process diagram of a diode resin mold for a bonding test. In (28A), the composite silver nanopaste layers 6 and 12 are applied onto the lead frames 2 and 4, respectively. The diode chip 8 is placed on the composite silver nanopaste layer 6, and the composite silver nanopaste layer 10 is applied on the diode chip 8. Finally, both ends of the connection terminal 14 are placed on the composite silver nanopaste layers 10 and 12 to complete the diode assembly 1. In (28B), the diode assembly 1 is fired in the electric furnace 16, and the composite silver nanopaste layers 6, 10, 12 are changed to silver conductor layers 6a, 10a, 12a. Further, the fired diode assembly 1 is sealed with a resin mold 20 to complete a diode resin mold body 18, and the diode resin mold body 18 is transferred to a VF test and a ΔVF test described later. The lead frames protruding from the left and right serve as an anode 22 and a cathode 24 as electrodes.
　図２９はダイオード樹脂モールド体のＶＦ、ΔＶＦの接合試験測定図である。（２９Ａ）では、直流電源２６を電流計２８と直列して前記アノード２２とカソード２４間に接続し、直流電圧を可変可能に印加する。（２９Ｂ）はＶＦ試験の説明図である。定格電流ＩＯが流れる順方向電圧ＶＦを測定する。順方向電圧ＶＦが小さいほど、接合面の電気抵抗が小さいので、良好な接合状態であることが分かる。（２９Ｃ）はΔＶＦ試験の説明図である。前記接合面での電気抵抗は順方向電流が大きくなるとジュール熱を発生し、ダイオード特性を悪くするから、熱伝導性が良いことが重要になる。この熱伝導性を調べるために、ΔＶＦ試験を行う。初めに、微小電流を流して順方向電圧ＶＦを測定し、その後に所定の大電流を一定時間流して、その直後の順方向電圧ＶＦを測定する。その差ΔＶＦ（ミリボルト）が小さいと、接合面を介して熱が効率よく伝導し、接合状態が良いことを示す。即ち、電気伝導性をＶＦ試験で、熱伝導性をΔＶＦ試験で測定する。 FIG. 29 is a joint test measurement diagram of VF and ΔVF of the diode resin mold body. In (29A), a DC power supply 26 is connected in series with an ammeter 28 between the anode 22 and the cathode 24, and a DC voltage is applied variably. (29B) is an explanatory diagram of the VF test. The forward voltage VF through which the rated current IO flows is measured. It can be seen that the smaller the forward voltage VF is, the smaller the electrical resistance of the joint surface is, and thus a better joined state. (29C) is an explanatory diagram of the ΔVF test. It is important that the electrical resistance at the joint surface has good thermal conductivity because Joule heat is generated when the forward current is increased and the diode characteristics are deteriorated. In order to investigate this thermal conductivity, a ΔVF test is performed. First, a forward current VF is measured by passing a minute current, and then a predetermined large current is passed for a certain time, and the forward voltage VF immediately after that is measured. When the difference ΔVF (millivolt) is small, heat is efficiently conducted through the joint surface, indicating that the joint state is good. That is, the electrical conductivity is measured by the VF test, and the thermal conductivity is measured by the ΔVF test.
　図３０は各種ペーストの大気中・窒素中焼成におけるＶＦの比較図である。複合銀ナノペーストとしてＰ２０、Ｐ２１、Ｐ２２、Ｐ２３の４種類から図２９に示されるダイオード樹脂モールド体が作製され、ＶＦ試験が行われた。比較のために従来から使用されている高温型ハンダであるＰｂ－５Ｓｎを用いて同じダイオード樹脂モールド体が作製され試験された。但し、図３０～図３５において、Ｐｂ－５Ｓｎを用いた焼成試験結果は全て窒素雰囲気下で得られたデータであり、そのことを明らかにするため、図３０～図３５にはＰｂ－５Ｓｎ（ｉｎ　Ｎ２）と記載されている。大気中焼成（空気中焼成）はボックス炉で実施され、窒素中焼成はリフロー炉が用いられた。Ｐｂ－５Ｓｎは窒素中焼成だけであり、このＰｂ－５Ｓｎの測定値と比較して、他のペーストの測定値が小さければ、従来の高温型ハンダより本発明ペーストが優れている（○）と判定され、同程度なら可（△）、大きければ不可（×）と判定される。窒素中焼成では４種類のペーストは○、大気中焼成はＰ２０は×だが、残り３種類では△であった。 FIG. 30 is a comparative diagram of VF when various pastes are fired in air and nitrogen. A diode resin mold body shown in FIG. 29 was prepared from four types of P20, P21, P22, and P23 as composite silver nanopaste, and a VF test was performed. For comparison, the same diode resin mold was manufactured and tested using Pb-5Sn, which is a high-temperature solder that has been conventionally used. However, in FIG. 30 to FIG. 35, all the firing test results using Pb-5Sn are data obtained under a nitrogen atmosphere, and in order to clarify this, FIG. 30 to FIG. in N2). Firing in the air (firing in the air) was performed in a box furnace, and a reflow furnace was used for firing in nitrogen. Pb-5Sn is only fired in nitrogen, and if the measured value of other pastes is small compared to the measured value of Pb-5Sn, the paste of the present invention is superior to the conventional high-temperature solder (◯). It is determined that it is acceptable (Δ) if it is approximately the same, and is impossible (×) if it is large. In the case of firing in nitrogen, four types of pastes were ◯, and in the case of firing in air, P20 was x, but the remaining three types were Δ.
　図３１は各種ペーストの大気中・窒素中焼成におけるΔＶＦの比較図である。図３０に使用されたＰ２０、Ｐ２１、Ｐ２２、Ｐ２３の４種類のダイオード樹脂モールド体が使用され、ΔＶＦ試験が行われた。図３０のＰｂ－５Ｓｎを用いたダイオード樹脂モールド体も試験された。同様に、大気中焼成（空気中焼成）はボックス炉で実施され、窒素中焼成はリフロー炉が用いられた。Ｐｂ－５Ｓｎは窒素中焼成だけであり、このＰｂ－５Ｓｎの測定値と比較して、他のペーストの測定値が小さければ、従来の高温ハンダより本発明ペーストが優れている（○）と判定され、同程度なら可（△）、大きければ不可（×）と判定される。窒素中焼成では４種類のペーストは○、大気中焼成はＰ２２は△だが、残り３種類は×であった。 FIG. 31 is a comparative diagram of ΔVF in the firing of various pastes in air and nitrogen. The four types of diode resin molds P20, P21, P22, and P23 used in FIG. 30 were used, and the ΔVF test was performed. A diode resin mold using Pb-5Sn of FIG. 30 was also tested. Similarly, firing in air (firing in air) was performed in a box furnace, and reflow furnace was used for firing in nitrogen. Pb-5Sn is only fired in nitrogen. If the measured value of other pastes is small compared to the measured value of Pb-5Sn, the paste of the present invention is judged to be superior to the conventional high-temperature solder (◯). If it is approximately the same, it is determined that it is acceptable (Δ), and if it is large, it is determined that it is impossible (x). In the case of firing in nitrogen, four types of pastes were ◯, and in the case of firing in air, P22 was Δ, but the remaining three types were x.
　表１３は、ＶＦ及びΔＶＦについて本発明ペーストと従来Ｐｂ－５Ｓｎハンダの比較表である。この表は、図３０及び図３１で得られた結果を集計したものである。窒素中焼成では、Ｐ２０～Ｐ２３の全てのペーストが、ＶＦ試験及びΔＶＦ試験で、Ｐｂ－５Ｓｎと比較して良（○）を示し、総合判定として全ペーストが良（○）である。他方、大気中焼成では、○を得たペーストはどれも無く、本発明ペーストは不合格となった。 Table 13 is a comparison table of the paste of the present invention and conventional Pb-5Sn solder for VF and ΔVF. This table is a summary of the results obtained in FIGS. In the firing in nitrogen, all pastes of P20 to P23 showed good (◯) in comparison with Pb-5Sn in the VF test and ΔVF test, and all pastes were good (◯) as a comprehensive judgment. On the other hand, in the air baking, none of the pastes obtained ○, and the paste of the present invention failed.
Figure JPOXMLDOC01-appb-T000013
Figure JPOXMLDOC01-appb-T000013
　図３２は各種ペーストの大気中焼成における初期・リフロー耐熱試験後でのＶＦの比較図である。前述した４種の複合銀ナノペーストＰ２０、Ｐ２１、Ｐ２２、Ｐ２３を大気中焼成したダイオード樹脂モールド体が使用された。比較のためにＰｂ－５Ｓｎを窒素中焼成したダイオード樹脂モールド体が使用された。ＶＦ試験は初期段階と、リフロー耐熱試験後に行われ、相互に比較された。ここで、リフロー耐熱試験とは、リフロー炉を用いて行うプログラム昇温試験法で、常温（室温）―２６０℃―常温（室温）の熱サイクル（５～１５分間、平均昇温率は２５℃／ｍｉｎ）を３サイクル実施して、ＶＦ及びΔＶＦを計測する試験法である。 FIG. 32 is a comparison diagram of VF after the initial reflow heat test in the firing of various pastes in the air. A diode resin mold body obtained by firing the above-described four kinds of composite silver nanopastes P20, P21, P22, and P23 in the atmosphere was used. For comparison, a diode resin mold body obtained by firing Pb-5Sn in nitrogen was used. The VF test was performed at the initial stage and after the reflow heat test, and compared with each other. Here, the reflow heat resistance test is a program temperature rise test method performed using a reflow furnace, and a normal temperature (room temperature) -260 ° C.-normal temperature (room temperature) thermal cycle (5 to 15 minutes, average temperature increase rate is 25 ° C. / Min) is a test method for measuring VF and ΔVF by performing three cycles.
　ところで、図１９～図２６では昇温率は３℃／ｍｉｎに設定されたが、実際のリフロー炉における平均昇温率は２５℃／ｍｉｎとかなり大きな値に設定されている。その理由は熱解析における空気中と窒素中における金属化温度Ｔ３を正確に測定するためである。
　Ｐｂ－５Ｓｎの測定値と比較して、他のペーストの測定値が小さければ、従来の高温ハンダより本発明ペーストが優れている（○）と判定され、同程度なら可（△）、大きければ不可（×）と判定される。初期試験では、Ｐ２３だけが（△）で、残り３種は（×）であった。リフロー耐熱試験後では、全てのペーストが（×）である。 By the way, in FIGS. 19 to 26, the temperature increase rate is set to 3 ° C./min, but the average temperature increase rate in the actual reflow furnace is set to a considerably large value of 25 ° C./min. The reason is to accurately measure the metallization temperature T3 in the air and nitrogen in the thermal analysis.
If the measured value of the other paste is small compared to the measured value of Pb-5Sn, it is judged that the paste of the present invention is superior to the conventional high-temperature solder (◯). It is judged as impossible (×). In the initial test, only P23 was (Δ) and the remaining three were (×). After the reflow heat test, all the pastes are (x).
　図３３は、各種ペーストの大気中焼成における初期・リフロー耐熱試験後のΔＶＦの比較図である。前述した４種の複合銀ナノペーストＰ２０、Ｐ２１、Ｐ２２、Ｐ２３を大気中焼成したダイオード樹脂モールド体が使用された。比較のためにＰｂ－５Ｓｎを大気中焼成したダイオード樹脂モールド体が使用された。ΔＶＦ試験は初期段階と、リフロー耐熱試験後に行われ、相互に比較された。Ｐｂ－５Ｓｎの測定値と比較して、Ｐ２２ペーストが初期試験では（△）で、他のペーストは全て（×）である。リフロー耐熱試験後では、４種類の全ペーストが（×）であった。 FIG. 33 is a comparative view of ΔVF after the initial and reflow heat test in the firing of various pastes in the air. A diode resin mold body obtained by firing the above-described four kinds of composite silver nanopastes P20, P21, P22, and P23 in the atmosphere was used. For comparison, a diode resin mold body obtained by firing Pb-5Sn in the air was used. The ΔVF test was performed at the initial stage and after the reflow heat test, and compared with each other. Compared with the measured value of Pb-5Sn, P22 paste is (Δ) in the initial test, and all other pastes are (×). After the reflow heat test, all four types of pastes were (x).
　表１４は、ＶＦ及びΔＶＦについて本発明ペーストと従来Ｐｂ－５Ｓｎハンダの比較表である。この表は、図３２及び図３３で得られた結果を集計したものである。ＶＦ値に関し、初期試験ではＰ２３が（△）であったが、その他ペーストは（×）であり、リフロー耐熱試験後は全てのペーストが（×）であった。また、ΔＶＦ値に関し、初期試験ではＰ２２が（△）であったが、その他ペーストは（×）であり、リフロー耐熱試験後は全てのペーストが（×）であった。従って、大気中総合判定では、４種類全部のペーストが不合格となった。 Table 14 is a comparison table of the paste of the present invention and conventional Pb-5Sn solder for VF and ΔVF. This table summarizes the results obtained in FIGS. 32 and 33. Regarding the VF value, P23 was (Δ) in the initial test, but the other paste was (×), and after the reflow heat test, all pastes were (×). Regarding the ΔVF value, P22 was (Δ) in the initial test, but the other paste was (×), and after the reflow heat test, all pastes were (×). Therefore, in the atmospheric comprehensive judgment, all four types of pastes were rejected.
Figure JPOXMLDOC01-appb-T000014
Figure JPOXMLDOC01-appb-T000014
　図３４は各種ペーストの窒素中焼成における初期・リフロー耐熱試験後でのＶＦの比較図である。前述した４種の複合銀ナノペーストＰ２０、Ｐ２１、Ｐ２２、Ｐ２３を窒素中焼成したダイオード樹脂モールド体が使用された。比較のためにＰｂ－５Ｓｎを窒素中焼成したダイオード樹脂モールド体が使用された。ＶＦ試験は初期段階と、リフロー耐熱試験後に行われ、相互に比較された。Ｐｂ－５Ｓｎの測定値と比較して、４種類の全ペーストが、初期段階及びリフロー耐熱試験後の測定で（○）を示した。 FIG. 34 is a comparison diagram of VF after the initial reflow heat test in firing various pastes in nitrogen. A diode resin mold body obtained by firing the above-described four kinds of composite silver nanopastes P20, P21, P22, and P23 in nitrogen was used. For comparison, a diode resin mold body obtained by firing Pb-5Sn in nitrogen was used. The VF test was performed at the initial stage and after the reflow heat test, and compared with each other. Compared with the measured value of Pb-5Sn, all the four types of pastes showed (◯) in the measurement at the initial stage and after the reflow heat test.
　図３５は、各種ペーストの窒素中焼成における初期・リフロー耐熱試験後のΔＶＦの比較図である。前述した４種の複合銀ナノペーストＰ２０、Ｐ２１、Ｐ２２、Ｐ２３を窒素中焼成したダイオード樹脂モールド体が使用された。比較のためにＰｂ－５Ｓｎを窒素中焼成したダイオード樹脂モールド体が使用された。ΔＶＦ試験は初期段階と、リフロー耐熱試験後に行われ、相互に比較された。Ｐｂ－５Ｓｎの測定値と比較して、４種類の全ペーストが、初期試験及びリフロー耐熱試験後の測定で（○）を示した。 FIG. 35 is a comparative view of ΔVF after the initial and reflow heat test in firing various pastes in nitrogen. A diode resin mold body obtained by firing the above-described four kinds of composite silver nanopastes P20, P21, P22, and P23 in nitrogen was used. For comparison, a diode resin mold body obtained by firing Pb-5Sn in nitrogen was used. The ΔVF test was performed at the initial stage and after the reflow heat resistance test and compared with each other. Compared with the measured value of Pb-5Sn, all four types of pastes showed (◯) in the measurement after the initial test and the reflow heat resistance test.
　表１５は、ＶＦ及びΔＶＦについて本発明ペーストと従来のＰｂ－５Ｓｎハンダの比較表である。この表は、図３４及び図３５で得られた結果を集計したものである。ＶＦ値及びΔＶＦ値に関し、初期段階及びリフロー耐熱試験後は全てのペーストが（○）であった。 Table 15 is a comparison table of the paste of the present invention and conventional Pb-5Sn solder for VF and ΔVF. This table summarizes the results obtained in FIGS. 34 and 35. Regarding the VF value and ΔVF value, all pastes were (◯) after the initial stage and after the reflow heat test.
Figure JPOXMLDOC01-appb-T000015
Figure JPOXMLDOC01-appb-T000015
　以上から得られた総合的結論は、本発明ペーストＰ２０～Ｐ２３は窒素中焼成の場合において、ＶＦ試験及びΔＶＦ試験で、従来のＰｂ－５Ｓｎと比較して、同等又はそれ以上の良成績を収めた。大気中焼成では、従来のＰｂ－５Ｓｎよりも、本発明ペーストは良好な特性が得られなかった。 The overall conclusion obtained from the above is that the pastes P20 to P23 of the present invention achieved the same or better results in the VF test and ΔVF test compared to the conventional Pb-5Sn when fired in nitrogen. It was. When fired in the air, the paste of the present invention did not provide better properties than conventional Pb-5Sn.
　本発明は、上記実施形態や変形例に限定されるものではなく、本発明の技術的思想を逸脱しない範囲における種々変形例、設計変更などをその技術的範囲内に包含するものであることは云うまでもない。 The present invention is not limited to the above-described embodiments and modifications, and includes various modifications and design changes within the technical scope without departing from the technical idea of the present invention. Needless to say.
　本発明によれば、銀原子の集合体からなる銀核の周囲に、炭素数１０又は１２いずれかのアルコール分子残基、アルコール分子誘導体及び／又はアルコール分子の一種以上からなる有機被覆層を形成した複合銀ナノ粒子と、銀微粒子と、樹脂を均一に混合して構成され、前記樹脂は３０℃以下で固体又は高粘度の非流動状態にあって前記複合銀ナノ粒子と前記銀微粒子を均一分散状態に保持し、加熱により流動化して塗着可能になる複合銀ナノペーストが提供される。非流動性により複合銀ナノ粒子の凝集を防止し、加熱流動性により塗着性能を発現するペーストが提供される。従って、本発明の複合銀ナノペーストは、プリント配線・導電性材料などの電子材料、磁気記録媒体・電磁波吸収体・電磁波共鳴器などの磁性材料、遠赤外材料・複合皮膜形成材などの構造材料、焼結助剤・コーティング材料などのセラミックス・金属材料、医療材料などの各種分野のペーストに適用できる。 According to the present invention, an organic coating layer composed of at least one alcohol molecule residue, alcohol molecule derivative and / or alcohol molecule having 10 or 12 carbon atoms is formed around a silver nucleus composed of an aggregate of silver atoms. The composite silver nanoparticles, the silver fine particles, and the resin are uniformly mixed, and the resin is in a solid or high-viscosity non-flowing state at 30 ° C. or less, and the composite silver nanoparticles and the silver fine particles are uniformly mixed. There is provided a composite silver nanopaste that is kept in a dispersed state and fluidized by heating to enable coating. A paste that prevents aggregation of composite silver nanoparticles by non-fluidity and develops coating performance by heat fluidity is provided. Therefore, the composite silver nanopaste of the present invention has a structure such as an electronic material such as a printed wiring / conductive material, a magnetic material such as a magnetic recording medium / electromagnetic wave absorber / electromagnetic resonator, a far infrared material / composite film forming material, etc. It can be applied to pastes in various fields such as materials, ceramics and metal materials such as sintering aids and coating materials, and medical materials.

Claims (14)

  1. 銀原子の集合体からなる銀核の周囲に、炭素数１０又は１２いずれかのアルコール分子残基、アルコール分子誘導体及び／又はアルコール分子の一種以上からなる有機被覆層を形成した複合銀ナノ粒子と、銀微粒子と、樹脂を混合して構成され、前記樹脂は３０℃以下で非流動状態にあって前記複合銀ナノ粒子と前記銀微粒子を均一分散状態に保持し、加熱により流動化して塗着可能になることを特徴とする複合銀ナノペースト。 Composite silver nanoparticles in which an organic coating layer composed of one or more of alcohol molecule residues, alcohol molecule derivatives and / or alcohol molecules having 10 or 12 carbon atoms is formed around a silver nucleus composed of an aggregate of silver atoms The silver fine particles and the resin are mixed, and the resin is in a non-flowing state at 30 ° C. or less, and the composite silver nanoparticles and the silver fine particles are kept in a uniformly dispersed state, and are fluidized by heating and applied. Composite silver nanopaste characterized by becoming possible.
  2. 前記銀核の平均粒径は１～２０ｎｍであり、前記銀微粒子の平均粒径は０．１～３．０μｍである請求項１に記載の複合銀ナノペースト。 2. The composite silver nanopaste according to claim 1, wherein the average particle diameter of the silver nuclei is 1 to 20 nm, and the average particle diameter of the silver fine particles is 0.1 to 3.0 μm.
  3. 前記複合銀ナノ粒子の重量は５～３０（ｗｔ％）、前記銀微粒子の重量は６０～９０（ｗｔ％）であり、前記樹脂の重量は１５（ｗｔ％）以下である請求項１又は２に記載の複合銀ナノペースト。 The weight of the composite silver nanoparticles is 5 to 30 (wt%), the weight of the silver fine particles is 60 to 90 (wt%), and the weight of the resin is 15 (wt%) or less. The composite silver nanopaste described in 1.
  4. 全体として銀含有率が８０（ｗｔ％）以上である請求項３に記載の複合銀ナノペースト。 The composite silver nanopaste according to claim 3, wherein the silver content as a whole is 80 (wt%) or more.
  5. 所望量の溶剤を添加して、３０℃以下でも流動状態化させて塗着可能にする請求項１～４のいずれかに記載の複合銀ナノペースト。 The composite silver nanopaste according to any one of claims 1 to 4, wherein a desired amount of a solvent is added so that the fluidized state can be applied even at 30 ° C or lower to enable coating.
  6. 基体に塗着し、窒素雰囲気下で２５０～５００℃の温度で焼成して有機物を気散させて銀膜を形成したときに、前記銀膜と基体との接合面積割合が７０％以上であり、前記銀膜の比抵抗が１０（μΩｃｍ）以下である請求項１～５のいずれかに記載の複合銀ナノペースト。 When the silver film is formed by applying to the substrate and baking in a nitrogen atmosphere at a temperature of 250 to 500 ° C. to disperse the organic matter, the bonding area ratio between the silver film and the substrate is 70% or more. 6. The composite silver nanopaste according to claim 1, wherein the specific resistance of the silver film is 10 (μΩcm) or less.
  7. 銀原子の集合体からなる銀核の周囲に、炭素数１０又は１２いずれかのアルコール分子残基、アルコール分子誘導体及び／又はアルコール分子の一種以上からなる有機被覆層を形成した所定量の複合銀ナノ粒子を、３０℃以下で非流動状態にあり加熱により流動化する所定量の樹脂に添加し、前記樹脂が流動状態になる温度で均一分散するまで混練してペースト中間体を形成し、このペースト中間体に所定量の銀微粒子を添加して前記温度で均一分散するまで混練し、混練後に前記樹脂が非流動状態になる温度まで冷却して、前記複合銀ナノ粒子と前記銀微粒子を前記樹脂中に均一分散状態に保持することを特徴とする複合銀ナノペーストの製法。 A predetermined amount of composite silver in which an organic coating layer composed of at least one of alcohol molecule residues having 10 or 12 carbon atoms, alcohol molecule derivatives and / or alcohol molecules is formed around a silver nucleus composed of an aggregate of silver atoms. The nanoparticles are added to a predetermined amount of resin that is in a non-flowing state at 30 ° C. or less and fluidized by heating, and kneaded until the resin is uniformly dispersed at a temperature at which the resin is in a flowing state to form a paste intermediate. A predetermined amount of silver fine particles are added to the paste intermediate and kneaded until uniformly dispersed at the temperature, and the resin is cooled to a temperature at which the resin becomes non-flowing after kneading, and the composite silver nanoparticles and the silver fine particles are A method for producing a composite silver nanopaste characterized by being kept in a uniformly dispersed state in a resin.
  8. 所定量の銀微粒子を、３０℃以下で非流動状態にあり加熱により流動化する所定量の樹脂に添加し、前記樹脂が流動状態になる温度で均一分散するまで混練してペースト中間体を形成し、このペースト中間体に、銀原子の集合体からなる銀核の周囲に、炭素数１０又は１２いずれかのアルコール分子残基、アルコール分子誘導体及び／又はアルコール分子の一種以上からなる有機被覆層を形成した所定量の複合銀ナノ粒子を添加して前記温度で均一分散するまで混練し、混練後に前記樹脂が非流動状態になる温度まで冷却して、前記複合銀ナノ粒子と前記銀微粒子を前記樹脂中に均一分散状態に保持することを特徴とする複合銀ナノペーストの製法。 A predetermined amount of silver fine particles is added to a predetermined amount of resin that is in a non-flowing state at 30 ° C. or less and fluidized by heating, and kneaded until the resin is uniformly dispersed at a temperature at which the resin is in a flowing state to form a paste intermediate In addition, an organic coating layer comprising at least one alcohol molecule residue, alcohol molecule derivative and / or alcohol molecule having 10 or 12 carbon atoms around a silver nucleus composed of an aggregate of silver atoms is provided in the paste intermediate. A predetermined amount of composite silver nanoparticles formed and kneaded until uniformly dispersed at the temperature, cooled to a temperature at which the resin becomes non-flowing after kneading, the composite silver nanoparticles and the silver fine particles A method for producing a composite silver nanopaste, wherein the resin is kept in a uniformly dispersed state.
  9. 銀原子の集合体からなる銀核の周囲に、炭素数１０又は１２のアルコール分子残基、アルコール分子誘導体又はアルコール分子の一種以上からなる有機被覆層を形成した所定量の複合銀ナノ粒子と、所定量の銀微粒子を、３０℃以下で非流動状態にあり加熱により流動化する所定量の樹脂に添加し、前記樹脂が流動状態になる温度で均一分散するまで混練し、混練後に前記樹脂が非流動状態になる温度まで冷却して、前記複合銀ナノ粒子と前記銀微粒子を前記樹脂中に均一分散状態に保持することを特徴とする複合銀ナノペーストの製法。 A predetermined amount of composite silver nanoparticles in which an organic coating layer composed of one or more of alcohol molecule residues, alcohol molecule derivatives or alcohol molecules having 10 or 12 carbon atoms is formed around a silver nucleus composed of an aggregate of silver atoms; A predetermined amount of silver fine particles is added to a predetermined amount of resin that is in a non-flowing state and fluidized by heating at 30 ° C. or less, and is kneaded until the resin is uniformly dispersed at a temperature at which the resin is in a flowing state. A method for producing a composite silver nanopaste, wherein the composite silver nanoparticle and the silver fine particle are maintained in a uniformly dispersed state in the resin by cooling to a temperature at which the resin becomes non-flowable.
  10. 前記銀核の平均粒径は１～２０ｎｍ、前記銀微粒子の平均粒径は０．１～３．０μｍである請求項７、８又は９に記載の複合銀ナノペーストの製法。 10. The method for producing a composite silver nanopaste according to claim 7, 8 or 9, wherein the average particle diameter of the silver nuclei is 1 to 20 nm, and the average particle diameter of the silver fine particles is 0.1 to 3.0 μm.
  11. 前記複合銀ナノ粒子の前記所定量は５～３０（ｗｔ％）、前記銀微粒子の前記所定量は６０～９０（ｗｔ％）、前記樹脂の前記所定量は１５（ｗｔ％）以下であり、全体として銀含有率が８０（ｗｔ％）以上である請求項７～１０のいずれかに記載の複合銀ナノペーストの製法。 The predetermined amount of the composite silver nanoparticles is 5 to 30 (wt%), the predetermined amount of the silver fine particles is 60 to 90 (wt%), and the predetermined amount of the resin is 15 (wt%) or less, The method for producing a composite silver nanopaste according to any one of claims 7 to 10, wherein the silver content as a whole is 80 (wt%) or more.
  12. 所望量の溶剤を添加して、３０℃以下でも流動状態化させて塗着可能なペーストにする請求項７～１１のいずれかに記載の複合銀ナノペーストの製法。 The method for producing a composite silver nanopaste according to any one of claims 7 to 11, wherein a desired amount of a solvent is added to make a paste that can be applied in a fluidized state even at 30 ° C or lower to form a paste that can be applied.
  13. 請求項１～６のいずれかに記載の流動状態にある複合銀ナノペーストを用意し、前記複合銀ナノペーストを下部基体上に塗着して接合用ペースト層を形成し、及び／又は前記接合用ペースト層の上に上部基体を載置して接合体を形成し、前記接合体を窒素雰囲気下及び／又は無荷重下で２５０～５００℃の温度で焼成することを特徴とするナノペースト接合方法。 A composite silver nanopaste in a fluid state according to any one of claims 1 to 6 is prepared, the composite silver nanopaste is applied onto a lower substrate to form a bonding paste layer, and / or the bonding A nano-paste bonding characterized in that an upper substrate is placed on a paste layer for forming a bonded body, and the bonded body is fired at a temperature of 250 to 500 ° C. in a nitrogen atmosphere and / or under no load. Method.
  14. 前記上部基体は半導体素子である請求項１３に記載のナノペースト接合方法。 The nanopaste bonding method according to claim 13, wherein the upper substrate is a semiconductor element.
PCT/JP2008/054971 2008-01-17 2008-03-18 Composite silver nanopaste, process for producing the composite silver nanopaste, and method for bonding the nanopaste WO2009116136A1 (en)

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PCT/JP2008/050558 WO2009090748A1 (en) 2008-01-17 2008-01-17 Silver composite nanoparticle and process and apparatus for producing the same
JP2010503690A JP5256281B2 (en) 2008-03-18 2008-03-18 Composite silver nanopaste, its production method and nanopaste bonding method
PCT/JP2008/054971 WO2009116136A1 (en) 2008-03-18 2008-03-18 Composite silver nanopaste, process for producing the composite silver nanopaste, and method for bonding the nanopaste
PCT/JP2008/061822 WO2009090767A1 (en) 2008-01-17 2008-06-30 Composite silver nanoparticles, composite silver nanopaste, process and apparatus for producing the composite silver nanopaste, joining method, and method for pattern formation
JP2010503736A JP5306322B2 (en) 2008-03-18 2008-07-04 Composite silver nanopaste, manufacturing method thereof, bonding method and pattern forming method
PCT/JP2008/062238 WO2009116185A1 (en) 2008-03-18 2008-07-04 Composite silver nanopaste, process for production thereof, method of connection and pattern formation process
EP08870788.0A EP2298471B1 (en) 2008-01-17 2008-12-25 Composite silver nanoparticles, composite silver nanopaste, and production methodof the same
CN2008801281306A CN101990474B (en) 2008-01-17 2008-12-25 Composite silver nanoparticles, composite silver nanopaste, and production method, production apparatus, conjugation method and patterning method of the same
KR1020107017975A KR101222304B1 (en) 2008-01-17 2008-12-25 Composite silver nanoparticles, composite silver nanopaste, and production method, production apparatus, conjugation method and patterning method of the same
PCT/JP2008/073660 WO2009090846A1 (en) 2008-01-17 2008-12-25 Composite silver nanoparticles, composite silver nanopaste, and production method, production apparatus, conjugation method and patterning method of the same
JP2009549977A JP4680313B2 (en) 2008-01-17 2008-12-25 COMPOSITE SILVER NANOPARTICLES, COMPOSITE SILVER NANOPASTE, PROCESS FOR PRODUCING THE SAME, MANUFACTURING APPARATUS, JOINING METHOD, AND PATTERN FORMING METHOD
US12/735,435 US8348134B2 (en) 2008-01-17 2008-12-25 Composite silver nanoparticle, composite silver nanopaste, bonding method and patterning method
PCT/JP2008/073751 WO2009090849A1 (en) 2008-01-17 2008-12-26 Method of wire bonding and structure including mounted electronic part
US13/707,384 US8906317B2 (en) 2008-01-17 2012-12-06 Production apparatus of composite silver nanoparticle
US13/707,298 US8459529B2 (en) 2008-01-17 2012-12-06 Production method of composite silver nanoparticle

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Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2011067085A1 (en) * 2009-12-04 2011-06-09 Thales Sealed electronic housing and method for the sealed assembly of such a housing
JP2011175871A (en) * 2010-02-24 2011-09-08 Osaka Municipal Technical Research Institute Joining material, and joining method
JP2013079431A (en) * 2011-10-05 2013-05-02 Nippon Synthetic Chem Ind Co Ltd:The Method for producing metal composite hyperfine particle
JP2013079430A (en) * 2011-10-05 2013-05-02 Nippon Synthetic Chem Ind Co Ltd:The Method for producing metal composite hyperfine particle
JP5306322B2 (en) * 2008-03-18 2013-10-02 株式会社応用ナノ粒子研究所 Composite silver nanopaste, manufacturing method thereof, bonding method and pattern forming method
WO2015182489A1 (en) * 2014-05-30 2015-12-03 Ｄｏｗａエレクトロニクス株式会社 Bonding material and bonding method in which same is used
US9960097B2 (en) 2014-03-11 2018-05-01 Fuji Electric Co., Ltd. Semiconductor device

Families Citing this family (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP5824201B2 (en) * 2009-09-11 2015-11-25 Ｄｏｗａエレクトロニクス株式会社 Bonding material and bonding method using the same
JP5487301B2 (en) * 2010-06-11 2014-05-07 Ｄｏｗａエレクトロニクス株式会社 Low-temperature sinterable bonding material and bonding method using the bonding material
WO2011155055A1 (en) 2010-06-11 2011-12-15 Ｄｏｗａエレクトロニクス株式会社 Low-temperature-sintering bonding material and bonding method using the bonding material
CN103250236B (en) * 2010-11-22 2016-09-14 同和电子科技有限公司 Grafting material and conjugant and joint method
JP6662619B2 (en) * 2015-11-30 2020-03-11 Ｄｏｗａエレクトロニクス株式会社 Joining material and joining method using the same
JP6927490B2 (en) * 2017-05-31 2021-09-01 株式会社応用ナノ粒子研究所 Heat dissipation structure
US20200269315A1 (en) 2017-09-20 2020-08-27 Sekisui Chemical Co., Ltd. Metal-containing particle, connection material, connection structure, method for manufacturing connection structure, conduction inspection member, and conduction inspection device

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2000076699A1 (en) * 1999-06-15 2000-12-21 Kimoto, Masaaki Ultrafine composite metal powder and method for producing the same
JP2001168140A (en) * 1999-12-10 2001-06-22 Ebara Corp Method for mounting semiconductor element and semiconductor device
JP2007042301A (en) * 2005-07-29 2007-02-15 Toda Kogyo Corp Conductive composition, conductive paste, and conductive film
JP2008091250A (en) * 2006-10-03 2008-04-17 Mitsuboshi Belting Ltd Low-temperature calcination type silver paste

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
TW476073B (en) * 1999-12-09 2002-02-11 Ebara Corp Solution containing metal component, method of and apparatus for forming thin metal film
US6519842B2 (en) * 1999-12-10 2003-02-18 Ebara Corporation Method for mounting semiconductor device
US6743395B2 (en) * 2000-03-22 2004-06-01 Ebara Corporation Composite metallic ultrafine particles and process for producing the same
JP4801958B2 (en) * 2005-09-29 2011-10-26 東海ゴム工業株式会社 Conductive paste
CN103117107B (en) * 2006-06-30 2016-08-10 三菱麻铁里亚尔株式会社 Form the compositions of electrode of solar battery, method and the solaode of this electrode of use

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2000076699A1 (en) * 1999-06-15 2000-12-21 Kimoto, Masaaki Ultrafine composite metal powder and method for producing the same
JP2001168140A (en) * 1999-12-10 2001-06-22 Ebara Corp Method for mounting semiconductor element and semiconductor device
JP2007042301A (en) * 2005-07-29 2007-02-15 Toda Kogyo Corp Conductive composition, conductive paste, and conductive film
JP2008091250A (en) * 2006-10-03 2008-04-17 Mitsuboshi Belting Ltd Low-temperature calcination type silver paste

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP5306322B2 (en) * 2008-03-18 2013-10-02 株式会社応用ナノ粒子研究所 Composite silver nanopaste, manufacturing method thereof, bonding method and pattern forming method
WO2011067085A1 (en) * 2009-12-04 2011-06-09 Thales Sealed electronic housing and method for the sealed assembly of such a housing
FR2953679A1 (en) * 2009-12-04 2011-06-10 Thales Sa HERMETIC ELECTRONIC HOUSING AND METHOD FOR HERMETICALLY ASSEMBLING A HOUSING
US8850698B2 (en) 2009-12-04 2014-10-07 Thales Method for the sealed assembly of an electronic housing
JP2011175871A (en) * 2010-02-24 2011-09-08 Osaka Municipal Technical Research Institute Joining material, and joining method
JP2013079431A (en) * 2011-10-05 2013-05-02 Nippon Synthetic Chem Ind Co Ltd:The Method for producing metal composite hyperfine particle
JP2013079430A (en) * 2011-10-05 2013-05-02 Nippon Synthetic Chem Ind Co Ltd:The Method for producing metal composite hyperfine particle
US9960097B2 (en) 2014-03-11 2018-05-01 Fuji Electric Co., Ltd. Semiconductor device
WO2015182489A1 (en) * 2014-05-30 2015-12-03 Ｄｏｗａエレクトロニクス株式会社 Bonding material and bonding method in which same is used
JP2015225842A (en) * 2014-05-30 2015-12-14 Ｄｏｗａエレクトロニクス株式会社 Joint material and joint method using the same
US10903185B2 (en) 2014-05-30 2021-01-26 Dowa Electronics Materials Co., Ltd. Bonding material and bonding method using same

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