DE112015002007T5 - Binding composition and metal-bound body and their use - Google Patents

Abstract

The following are provided: a bonding composition capable of giving a metal-bonded body having a dense bonding layer and high bonding reliability, and a metal-bonded body using them. The composition for bonding is in a pasty state and contains inorganic particles, an organic component and a dispersing medium, and is characterized by an average diameter of the inorganic particles and a crystallite diameter thereof of 1 to 20 μm and 4 to 40 nm, respectively, and metal particles having a particle diameter of 1 to 100 nm, which adhere to at least a part of the surface of the inorganic particles.

Description

Technical area

This invention relates to a binder composition composed mainly of inorganic particles and a metal-bonded body using the binder composition, and more particularly relates to a binder composition capable of giving a metal-bonded body which promotes a dense bonding layer and high binding reliability a relatively low bonding temperature, and a metal-bonded body using the binding composition.

background

For mechanically and / or electrically and / or thermally bonding a metal component and another metal component, conventionally solder, a conductive adhesive, a silver paste, an anisotropically conductive film and the like have been used. The conductive adhesive, the silver paste and the anisotropic conductive film are sometimes used for bonding not only the metal components but also the ceramic components, resin components. For example, there is binding of a light-emitting element such as LED to a substrate, bonding of a semiconductor type to a substrate, and further bonding of these substrates to a radiation part.

Among them, an adhesive, a paste and a film containing the solder and a conductive filler made of a metal are used for bonding a region requiring electrical bonding. In addition, because a metal generally has a high thermal conductivity, this paste and film containing the solder and a conductive filler made of a metal can be used to increase the heat dissipation.

In contrast, when, for example, a lighting device or a high-luminance light-emitting device is produced by using a light-emitting element such as LED or when a semiconductor device is produced using a semiconductor element called an energy device and high in efficiency high temperature, a calorific value tends to increase. Although an efficiency of a device or element for reducing heat generation is to be improved, a sufficient result at this time has not yet been obtained, and the operating temperature of a device or element is practically increased.

From a viewpoint of preventing damage to a device in bonding, a binder material capable of ensuring sufficient strength at a low binding temperature (for example, at 300 ° C or less) is required. Therefore, with respect to the bonding material for bonding a device, an element or the like, not only is it necessary to lower the bonding temperature but also to impart sufficient thermal resistance which tolerates an increase in the operating temperature due to the effect of the device after bonding and can maintain sufficient bond strength, but conventional binder materials often can not sufficiently meet this requirement.

For example, the parts are bonded to the melting point or more (refluxing method) by soldering via a method of heating the metal, but because the melting point is unique to the composition in general, when attempting to increase the heat-resistive temperature, the Heat (binding) temperature also increased.

In addition, when multiple elements and substrates are overlapped, it is necessary to provide heating steps for the number of layers to be overlapped, and to prevent melting at the already bonded portion, it is necessary to have a melting point (bonding temperature) of a solder material Further, it is necessary that kinds of the chemical composition of the soldering material are required for the number of overlapping layers, and thus the handling becomes complicated.

In addition, as a high-temperature brazing material used at a high temperature, a brazing material containing lead is conventionally used. Because lead is toxic, a solder is drastically changed into a lead-free solder. However, because there is no other good substitute for the high-temperature brazing material, the lead-containing brazing material is still used, but a lead-free bonding material is desired for environmental reasons.

In the other prior art, for example Patent Literature 1 ( Japanese Patent 4928639 ) discloses a bonded material containing silver nanoparticles having an average primary particle size of 1 to 200 nm and coated with an organic substance having 6 carbon atoms, and containing a flux component containing at least one of oxydiacetic acid or malonic acid and a dispersion medium and in which particles having an average particle size of 0.5 to 3.0 μm are added to the binder, whereby the bonding force can be further improved.

In Patent Literature 2 ( Japanese Patent 5151150 A binder is disclosed which contains a metal particle with a particle size of 1 nm to 5 μm and is coated with an organic substance containing one or more types of functional group selected from the groups of carboxylic acids, alcohols and amines, and silver oxide. Wherein a total weight ratio of the metal particle and the silver oxide within the composition is 70 to 95%, a composition rate of silver oxide to metal particles whose surface is coated with the organic substance is within a weight ratio range of more than 0 and less than 400, and wherein an exothermic peak between 100 ° C to 140 ° C is observed when heated at a temperature elevation rate of 1 ° C / min in the atmosphere. In the bonding material, sintering with the metal particles can be achieved by reduction of the silver oxide.

Further, in Patent Literature 3 (Laid Japanese Patent Application 2011-21255 ) discloses a composite nanometal paste containing as metallic components metallic composite nanoparticles comprising metal cores having an average particle size X (nm) and an organic coating layer formed around the environment, metallic nano-filler particles having an average particle size d (nm and metallic filler particles having an average particle size of D (nm) satisfying the first relationship of X <d <D and the second relationship of X <d <100 (nm), and characterized in that when a metal layer is volatilized the organic coating layer is formed by sintering, the composite metal nanoparticles, the metal nano-filler particles and the metallic filler particles are not sintered. In the composite nanometal paste, by filling a space formed between the metal particles having a large particle size and metal particles having a small particle size, the dense sintered layer can be obtained.

Prior art literature

patent literature

• Patent Literature 1: Japanese Patent 4928639
• Patent Literature 2: Japanese Patent 5151150
• Patent Literature 3: Japanese Patent Publication 2011-21255

Summary of the invention

Problem to be solved by the invention

The dense structure of the binding portion of the bonded portion described in the above Patent Literature 1 is not sufficient, the binding reliability (for example, the bonding strength after thermal cycling) can not be ensured. The binder material described in the above Patent Literature 2 has a large volume shrinkage of the silver oxide particles during the bonding process, and it is difficult to control the thickness of the bonding layer and the gap between the particles constituting the bonding layer, and thus a sufficient bonding reliability can not to be obtained. In the composite nanometal paste described in the above Patent Literature 3, it is necessary because the part in which the large particles are in contact with each other can not be sintered at a low temperature for obtaining a sufficient bonding ability at a high temperature Temperature of 350 ° C or more to sinter.

In view of the above circumstances, the object of this invention is to provide a binder composition which can give a metal-bonded body having a dense bonding layer and a metal-bonded body with high reliability at a relatively low bonding temperature and a metal-bonded body using the binding composition specify.

Means of solving the problems

In order to achieve the above objects, as a result of the intensive study of the inventors regarding the inorganic particles, etc. contained in the binder composition, it has been found that the object can be effectively achieved by using inorganic particles having an adequate crystallite diameter, etc ., and thus this invention has been completed.

For this invention can provide a binder composition containing inorganic particles, an organic component and a dispersing medium, wherein

an average particle size (P _L ) and a crystallite diameter (C _L ) of an inorganic particle are 1 to 20 μm and 4 to 40 nm, respectively, and

Metal particles having a particle size (P _s ) of 1 to 100 nm are bonded to at least part of the surface of the inorganic particles.

When the metal particles having a particle size (P _S ) of 1 to 100 nm on at least a part of the surface of the inorganic particle having the average particle size (P _L ) and the crystallite diameter (C _L ) of the inorganic particle of 1 to 20 microns or 4 to 40 nm, it is possible to form a dense bonding layer at a relatively low bonding temperature (for example, 300 ° C or less). The above-mentioned inorganic particles may be composed of a metal and composed of the same kind of metal as the above-mentioned metal particles.

The average particle size (P _L ) of the inorganic particles can be measured by a dynamic light scattering method, a small-angle X-ray diffraction method or the like. As another method of measuring the average particle size (P _L ), there is a method of calculating a picked-up photo using an electron scanning microscope or a transmission electron microscope. The particle size (P _s ) of the metal particle adhering to the inorganic particle can be obtained from an observed image using electron scanning microscopy or transmission electron microscopy.

When the dynamic light scattering method is employed, the average particle size can be expressed as an average diameter (D50) based on the volume measured by a dynamic light scattering type particle size distribution meter LB-550 available from HORIBA Ltd .. Specifically First, several drops of the inorganic particle dispersion are added dropwise in 10 ml of a dispersion medium and the mixture dispersed by shaking by hand or ultrasonic energy, to prepare a test sample. Then, 3 ml of the measuring sample is poured into a cell of LB-550, and measurement is carried out under the conditions mentioned below.

measurement conditions

• Number of data read times: 100 times
• Temperature inside the cell holder: 25 ° C

display conditions

• Distribution mode: Standard
• Number of repetitions: 50 times
• Particle size standard: volume standard
• Refractive index of the dispersed material: 0.200 to 3.900 (in silver)
• Refractive index of the dispersion medium: 1.36 (when ethanol is a major component)

system settings

• Intensity standard: dynamic
• Upper limit of the litter intensity range: 10 000,00
• Lower limit of the scattering intensity range: 1.00

In this method, when the particle size is beyond 5 μm, it is difficult to obtain an accurate measurement. In such a case, an authentic average of 50 to 100 particles of electroscopic photograph, taken using a laser diffraction scattering method or electron scanning microscopy.

An inorganic particle is composed of a plurality of crystallites (maximum size of single crystal) and the crystallite diameter (C _L ) of the inorganic particle represents the size of the crystallite. The crystallite diameter (C _L ) can be determined, for example, by a wide angle X-ray diffraction methods are measured. In the wide-angle X-ray diffraction method, the crystallite diameter can be measured within the range where 2θ is 30 to 80 ° by the diffraction method, for example, using RINT-Ultima III available from Rigaku Corporation. In this case, samples should be measured by dilution so as to have a flat surface on a glass plate about 0.1 to 1 mm deep from a central region concave area. Furthermore, the crystallite diameter (D) calculated by substituting half a band width of a obtained diffraction spectrum using JADE available from Rigaku Corporation into the Scherrer equation should be regarded as the average particle size. D = Kλ / Bcosθ Herein: K: Scherrer constant (0.9), λ: wavelength of the X-ray source, B: bandwidth of the diffraction line, θ: Bragg angle.

It is preferable that the crystallite diameter (C _L ) of the metal particles adhering to at least a part of the surface of the inorganic particles is 4 to 40 nm. When the crystallite diameter (C _L ) is 4 to 40 nm, the metal particle may have a good low-temperature sintering property. The crystallite diameter (C _L ) of the metal particle can be obtained, for example, by the above wide-angle X-ray diffraction method.

It is preferable that an organic component is coated on the at least a part of the surface of the metal particle (namely, at least part of the surface of the metal particle is covered with an organic protective layer composed of the organic component) and the organic component (organic protective layer) Contains amine. In order to maintain the nanometer size metal particle stably exhibiting a melting point lowering ability, it is necessary to cover at least a part of the surface of the inorganic particle. Because the functional group of the amine can adsorb on the surface of the metal particle at an adequate strength, it is suitably used as the organic protective layer.

The inorganic particle and the metal particle used in the binder composition of this invention are not particularly limited as long as they are within the range so that the effectiveness of this invention is not impaired, and the metal particle is preferably a silver particle, and further, the inorganic one Particles more preferably a silver particle. Because the silver particle is relatively stable, it is possible to store it for a long time, and can be produced more cheaply compared with a gold particle or palladium particle.

When using particles having different particle sizes of the binder composition, it is necessary to pay attention to a uniform dispersibility, and if the dispersion is not uniform, the binder layer may be porous (lowering the binding reliability). In contrast, in the binder composition of this invention, because the fine metal particles adhere to the surface of the inorganic particle, good dispersibility can be ensured. Because fusion and sintering of the particles are uniform with each other, a dense bonding layer can be obtained as a result (high bonding reliability).

In the binder composition of this invention, when the inorganic particle and the organic component are measured by TG-DTA within the range of room temperature to 550 ° C in the atmosphere, it is preferable that the weight immediately after the maximum exothermic peak is 150 to 300 ° C is increased.

In general, the exothermic peak of DTS is due to oxidation decomposition of the organic components and means sintering of the particles by decomposition of the dispersant adhering to the particles. Although the particle itself is instantaneously oxidized when silver is used as a particle, since the particle is reduced by self-reduction of silver, there is almost no effect on the oxidation. When used as a binder, it is believed that the particle with the interface the body to be bound is in contact during sintering of the particle, the shrinkage due to sintering of the particle can be inhibited by the weight increase and the adhesion to the interface of the body to be bonded can be ensured without a pressure in binding is imposed, what a successful binding without pressure.

In the binder composition according to this invention, it is preferable that a maximum increase ratio (%) of the weight increase is less than 0.2%.

With respect to the weight increase, when the maximum increase ratio is 0.2% or more, the deformation of the bonding layer is directly influenced. Because heat is generally conducted from one edge of a body to be bonded, sintering from the edge begins. For example, with a large bonding area of 2 mm × 2 mm or more, because the sintering speed at the edge and the center is different, and when the weight increasing ratio is 0.2% or more, the bonding layer becomes deformed at the edge and the center bound. In such a case, after bonding, there is the possibility that the reliability of heat resistance is adversely affected.

According to the method of bonding a metal body of the invention, a method for bonding surfaces of two metal bodies using the binder composition of this invention can be given, wherein a binding atmosphere is the atmosphere or a mixed atmosphere of air and nitrogen, and when the inorganic particle and the When the organic component is measured by TMA within the range of from room temperature to 500 ° C under the binding atmosphere, the bonding temperature is adjusted to a temperature such that a rate of dimensional change from room temperature is -1.0 to 1.0%.

In measuring the inorganic particle and the organic component by TMA within the range of room temperature to 500 ° C under such a binding atmosphere, by setting the rate of dimensional change from room temperature to -1.0% or more, the adhesion to the interface of the body to be bound can be ensured even when the binding is performed without pressure, and by setting to 1.0% or less, the residual stress caused by the heat history in the bonded body can be reduced.

In the bonding method of the metal body of this invention, it is preferable that the bonding temperature has a temperature at which the maximum exothermic peak is generated or set higher when the inorganic particle and the organic component are within the range of from room temperature to about 100% by TG-DTA 500 ° C is measured under the binding atmosphere.

By setting the bonding temperature to a temperature at which the maximum exothermic peak is generated or higher, the sintering for bonding can proceed.

According to the metal-bonded body of this invention, a metal-bonded body can be given in which surfaces of two metal bodies are bonded by using the binder composition of this invention and a thickness of a bonding layer of the metal-bonded body is 30 to 150 μm.

Because the bonding layer of the metal-bonded body of this invention is composed of the inorganic particles and the metal particles, the melting point after sintering is the same as the bulk material as opposed to a solder material. As compared with the bonding layer formed by a brazing material, hot-cold shock reliability can be obtained at a higher temperature. When the upper limit of the hot-cold shock temperature is 200 ° C. or more, a difference in thermal expansion coefficients of the body to be bonded and the bonding layer becomes large, and if the thickness of the bonding layer is less than 30 μm, it is not possible to weaken the thermal stress to break. On the other hand, if the thickness of the bonding layer is more than 150 μm, it is difficult because an amount of the binder composition for coating becomes large to achieve sintering due to the respective increased amount of the organic substance, and thus it is not possible to obtain a dense bonding layer.

Therefore, when the thickness of the bonding layer is 30 to 150 μm, it is possible to make the bonding layer dense and weaken the thermal stress due to a difference in the thermal expansion coefficient of the body to be bonded. As a result, the metal-bonded body according to this invention has a high binding reliability.

Effect of the invention

This invention can provide a binder composition capable of yielding a metal-bonded body having a dense bonding layer and a metal-bonded body having high reliability at a relatively low bonding temperature, and a metal-bonded body using the bonding composition.

Means of solving the problems

A preferred embodiment of the binder composition and the metal-bonded body using the composition of this invention will be described in detail. Furthermore, the description below indicates only one embodiment of this invention, and the invention is not limited thereto, and repetitive descriptions may be omitted.

(1) binding composition

The binder composition of this embodiment is a pasty binder composition containing an inorganic particle and an organic component. Hereinafter, each component of the binding composition will be explained

(1-1) Inorganic particles

Although the inorganic particles of the binder composition of this embodiment are not particularly limited, it is preferable that the conductivity of a binder layer obtained by using the binder composition of this embodiment can be improved to be metal, with the ionization tendency being lower than that of zinc is.

Examples of the metal include at least one of gold, silver, copper, nickel, bismuth, tin, iron and platinum group elements such as ruthenium, rhodium, palladium, osmium, iridium and platinum. As the metal, at least one of metal selected from the group consisting of gold, silver, copper, nickel, bismuth, tin and the platinum group is preferable, and more preferable is copper or a metal in which the ionization tendency is smaller as copper, that is at least one of the group consisting of gold, silver, copper and platinum.

The most preferred inorganic particles are silver particles because silver particles are relatively stable for storage for a long time, and further, it can be produced inexpensively in comparison with gold particles, palladium particles and the like.

These metals may be used alone or in combination of two or more, and as a method of combination, there is a case of using alloy particles containing a plurality of metals or a case using metal particles having a core-shell structure or a multi-layered one Structure.

For example, when silver particles are used as the inorganic particles of the binder composition, the electrical conductivity of the adhesive layer formed by using the binder composition according to this embodiment is excellent, but in view of the migration problem, migration may be difficult to occur by using the silver and binder composition other metals. As "other metals", preferred are metals whose ionization series is more noble than hydrogen, that is, gold, copper, platinum and palladium.

An average particle size (P _L ) of the inorganic particle used in the binder composition of this invention is 1 to 20 μm. When using the inorganic particle having an average particle size (P _L ) of 1 to 20 μm, the volume shrinkage by sintering can be reduced to obtain a homogeneous and dense bonding layer.

When using a small particle having an average particle size (P _L ) of less than 1 μm, although sintering may proceed at a low temperature as the sintering of the particles expires, the volume shrinkage becomes large due to an increase in the average particle size Binding bodies can not follow the volume shrinkage. As a result, defects such as holes in the bonding layer are generated, and the bonding strength and reliability of the bonded body are lowered. When using a particle having an average particle size (P _L ) of more than 20 μm, sintering can not proceed at a low temperature, and large holes formed between the particles remain after sintering.

The average particle size (P _L ) of the inorganic particle is preferably 1 to 15 μm, more preferably 1 to 10 μm. The above range is preferable in view of the fact that the sintering can proceed at a low temperature and that the holes formed between the particles can be reduced as much as possible.

As mentioned above, the average particle size (P _L ) of the inorganic particle can be measured by a dynamic light scattering method, a small angle X-ray diffraction scattering method, or the like. As another method for measuring the average particle size (P _L ), there is a method in which an authentic average of 50 to 100 particles is calculated from the photograph taken by using an electron scanning microscope or a transmission electron microscope.

The crystallite diameter (C _L ) of the inorganic particle used in the binder composition of this invention is 4 to 40 nm. When the crystallite diameter (C _L ) of the inorganic particle is 4 to 40 nm, the sintering proceeds with increase of the crystallite diameter (C _L ) at a relatively low binding temperature (for example, 300 ° C or lower).

However, it is necessary to fuse the inorganic particles together at a high temperature because the inorganic particles having an average particle size (P _L ) of 1 to 20 μm have a radius of curvature of the order of microns. In contrast, among the inorganic particles used in the binder composition of this invention, metal particles having a particle size (P _s ) of 1 to 100 nm adhere to at least a part of the surface of the inorganic particles, and thus at least a part of the particles has one Radius of curvature on the order of nanometers. As a result, the inorganic particle can be fused at a low temperature.

The crystallite diameter (C _L ) of the inorganic particle is preferably 10 to 40 μm, more preferably 15 to 40 nm. If the crystallite diameter is too small, sintering may easily occur at a low temperature, but the particle remains as non-crystalline. Sintered part after bonding, because the part is a point where a change is made by heating, and thus the above-mentioned range is preferable in view of the reliability of the heat resistance.

The inorganic particle and the metal particle in the binder composition of this invention preferably contain no particle that can be thermally decomposed to form a metal. When a particle is included which can be thermally decomposed to produce a metal such as silver oxide or silver carbonate, volume shrinkage becomes large because the particle gives gases such as oxygen and carbon dioxide and a metal particle upon decomposition. Because such volume shrinkage makes binding without pressure difficult, it would be better for the particle, which can be thermally decomposed, to be a metal that is not used as an inorganic particle in the binder composition.

It is preferable that when measuring the inorganic particle and the organic component by TG-DTA within the range of room temperature to 550 ° C in the atmosphere, the weight immediately after the maximum exothermic peak at 150 to 300 ° C is increased.

In general, the exothermic peak of DTA occurs by oxidation decomposition of inorganic components and means sintering of the particles by decomposition of the dispersant adhered to the particles. Although the particle itself is instantaneously oxidized when silver is used as a particle, there is almost no influence of oxidation because the particle itself is reduced by reduction of silver. When used for bonding, it is considered that the particle is in contact with the interface of the body to be bonded upon sintering of the particle, whereby the shrinkage can be inhibited by sintering the particle by the increase in weight and the adhesion to the interface of the particle to be bound be ensured without a pressure on binding is imposed, resulting in the success of binding without pressure.

In the binder composition of this invention, it is further preferable that when measuring the inorganic particle and the organic component by TG-DTA within the range of from room temperature to 550 ° S in the atmosphere, the weight immediately after the maximum exothermic peak 150 to 300 ° C is increased, and the maximum increase ratio (%) of the weight increase is less than 0.2%.

With respect to the weight increase, when the maximum increase ratio is 0.2% or more, the deformation of the bonding layer is directly influenced. In general, sintering begins from the edge because heat is conducted from an edge of a body to be bonded. For example, when bonding a large area of 2 mm × 2 mm or more, because the sintering speed is slightly different at the edge and when the weight-increasing ratio is 0.2% or more, the bonding layer deforms at the edge and in a deformed manner tied to the middle. In such a case, after bonding, there is a possibility that the reliability of heat resistance is adversely affected.

(1-2) metal particles adhering to at least a part of the surface of the inorganic particle

As the metal particles, the same metal particle listed as the metal particle of the inorganic particle can be used. When the above inorganic particle is a metal particle (core metal particle), the core metal particle may be the same or different from the metal particle (surface metal particle) adhering to the surface.

Examples of the metal include at least one of gold, silver, copper, nickel, bismuth, tin, iron and platinum group elements such as ruthenium, rhodium, palladium, osmium, iridium and platinum. As the metal, at least one metal selected from the group consisting of gold, silver, copper, nickel, bismuth, tin and the platinum group is preferable, and more preferable is copper or a metal in which the ionization tendency is smaller than copper that is, at least one selected from the group consisting of gold, platinum, silver and copper.

The most preferable inorganic particle is silver particle, because the silver particle is relatively stable when stored for a long time, and further can be produced favorably in comparison with the gold particle, palladium particle and the like.

These metals may be used alone or in combination of two or more, and as the method of combination, there is the case of using alloy particles containing a plurality of metals or a case using metal particles having a core-shell structure or a metal shell complex structure.

It is preferable that the crystallite diameter of the metal particles adhering to at least a part of the surface of the inorganic particle is 4 to 40 nm. When the crystallite diameter is 4 to 40 nm, fusion and sintering are easy to occur at low temperature.

The crystallite diameter of the metal particle is more preferably 7 to 37 nm, most preferably 10 to 35 nm. Within this range, fusion and sintering are easy to proceed at low temperature.

The average particle size (P _s ) of the metal particle is not particularly limited as long as it is within this range, so that the effect of this invention is not impaired, and it is preferable that the metal particle has a nanometer size, showing a capability of melting point depression. and more preferably, it is 1 to 100 nm. When the average particle size (P _s ) of the metal particle is 1 nm or more, a binder composition which gives a good bonding layer can be obtained, and the production cost of the metal particle is not expensive, which is practical is. When the size is 100 nm or less, it is preferable that the dispersibility of the metal particle does not vary slightly with the passage of time.

The average particle size (P _S ) of the metal particle is preferably 5 to 80 nm, more preferably 10 to 70 nm. Within this range, the low-temperature sintering can be ensured, and the dispersant adhering to the particle can be rejected with respect to the relative surface area and it is possible to form a good bonding layer.

For a metal particle of nanometer size to exist stably, it is necessary that an organic substance exists on the surface of the metal particle in a certain amount. The organic substance is preferably an amine and / or a carboxylic acid or a high molecular weight dispersant. The functional group of the amine or carboxylic acid adsorbs to the surface of the metal particle at an adequate strength, preventing the metal particles from interacting with each other, and contributing to the stability of the metal particles under storage conditions. The organic substance adhering to the surface of the metal particle appears to move away from the surface of the metal particle upon heating and / or to volatilize, thereby accelerating the fusion of the metal particles with each other and bonding to the substrate.

An organic component adheres to at least a part of the surface of the metal particle (namely, at least part of the surface of the metal particle is covered with an organic protective layer composed of an organic component), and the organic component (organic protective layer) preferably contains an amine. For storing the nanometer size metal particle showing a melting point depression ability, it is necessary to cover at least a part of the surface of the metal particle. Because the functional group of the amine can adsorb to the surface of the metal particle at an appropriate strength, it is suitably used as the organic protective layer.

The above organic component is an organic substance that prevents agglomeration of the metal particles by adhering to the metal particles, and is preferably configured as an alkylamine and a polymer dispersant. By adhering the polymer dispersant to at least a part of the metal particles in an appropriate amount, the dispersibility of the metal particles can be maintained without losing the low-temperature sintering property. The morphology of the adhesion or the coating is not particularly defined, but in this embodiment, the organic component preferably contains an amine in view of dispersibility and conductivity. It is believed that the amine is adsorbed to the surfaces of the metal particles at an adequate strength via the functional group to prevent contact of the metal particles with each other, contributing to the stability of the metal particles during storage, and by heating and / or Volatilization of the surface of the metal particles accelerates the fusion of the metal particles with each other and the binding of the metal particles to the substrate.

The amines used herein are not particularly limited and contain an amine having 2 to 20 carbon atoms, for example, a primary amine such as alkylamine (linear alkylamine or side chain) such as oleylamine, butylamine, pentylamine, hexylamine or hexylamine, an alkoxyamine such as N- (3 -Methoxypropyl) propane-1,3-diamine, 2-methoxyethylamine, 3-methoxypropylamine or 3-ethoxypropylamine, a cycloalkylamine such as cyclopentylamine or cyclohexylamine, an allylamine such as aniline; a secondary amine such as dipropylamine, dibutylamine, piperidine or hexamethyleneimine; and tertiary amine such as tripropylamine, dimethylpropanediamine, cyclohexyldimethylamine, pyridine or quinoline, octylamine and the like, and is preferably an amine having 4 to 7 carbon atoms. Examples of the low-boiling amine of 4 to 7 carbon atoms include heptylamine, butylamine, pentylamine and hexylamine. Because the amine having 4 to 7 carbon atoms can move and / or volatilize at a relatively low temperature, it is possible to fully apply the low-temperature sintering of the metal particle. By the low-temperature sintering property of the metal particle, the metal particle starts to sinter the inorganic particle (large particle) or the inorganic particle itself at a low temperature, and thus it becomes possible to develop the effect that the gap between the inorganic particles filled and the sintering rate of the inorganic particles is accelerated.

An amine of short length having 5 or less carbon atoms is not particularly limited when a distribution coefficient Log P is -1.0 to 1.4, and it may be linear or branched and have a side chain. Examples of the short chain amine include ethylamine (-0.3) propylamine (0.5), butylamine (1.0), N- (3-methoxypropyl) propane-1,3-diamine (-0.6), 1.2 Ethanediamine, N- (3-methoxypropyl) - (- 0.9), 2-methoxyethylamine (-0.9), 3-methoxypropylamine (-0.5), 3-ethoxypropylamine (-0.1), 1, 4-butanediamine (-0.9), 1,5-pentanediamine (-0.6), pentanolamine (-0.3), aminoisobutanol (-0.8) and the like, and among them, an alkoxyamine is preferable.

The amine is not limited to a linear type and may have a side chain to control the volatilization temperature. When the organic component is chemically or physically bound to these metal particles, the organic component may be converted to an anion or cation, and in this embodiment, the above organic components contain an ion or a complex derived from the organic components.

The above amine may be a compound having a functional group other than an amine such as a hydroxyl group, carboxyl group, alkoxy group, carbonyl group, ester group or mercapto group. The amine may be used alone or in combination of two or more. In addition, a boiling point under normal pressure is preferably 300 ° C or less, more preferably 250 ° C or less.

The organic substance adhered to the metal particle may contain a carboxylic acid in addition to the amine within the scope that the effect of this invention is not impaired. In the carboxylic acid, the carboxyl group in a molecule has a relatively high polarity to cause interaction due to hydrogen bonding, and the remaining portion other than the functional group shows a relatively low polarity. Furthermore, the carboxyl group tends to show an acidic property. When the carboxylic acid is located on at least part of the surface of the metal particles (namely, at least part of the surface of the metal particles covered with) of the binder composition of this embodiment, it is possible to sufficiently affinity the organic component and the metal particles to prevent coagulation of the metal particles (enhancement of dispersibility).

As the carboxylic acid, a compound having at least one carboxyl group can be widely used, and examples include formic acid, oxalic acid, acetic acid, hexanoic acid, acrylic acid, octylic acid, oleic acid and the like. A carboxyl group in a part of the carboxylic acid may form a salt with a metallic ion. With respect to the metal ion, two or more metal ions may be contained.

The carboxylic acid may be a compound containing a functional group other than the carboxyl group such as an amino group, hydroxyl group, alkoxy group, carbonyl group, ester group or mercapto group. In this case, the number of carboxyl groups is preferably more than the number of functional groups other than the carboxyl groups. The carboxylic acid may be used alone or in combination of two or more. In addition, it is preferable that a boiling point under normal pressure is preferably 300 ° C or less, more preferably 250 ° C or less. Furthermore, an amine and a carboxylic acid form an amide. Because the amide group is adequately adsorbed on the surface of the silver particle, the amide group may be contained in the organic component.

As the above polymer dispersant, any commercial polymer dispersant can be used. Examples of the commercially available polymer dispersants include SOLSPERSE 11200, SOLSPERSE 13940, SOLSPERSE 16000, SOLSPERSE 17000, SOLSPERSE 18000, SOLSPERSE 20000, SOLSPERSE 24000, SOLSPERSE 26000, SOLSPERSE 27000 and SOLSPERSE 28000 (available from Lubrizol Japan Corporation); DISPERBYK 142, DISPERBYK 160, DISPERBYK 161, DISPERBYK 162, DISPERBYK 163, DISPERBYK 166, DISPERBYK 170, DISPERBYK 180, DISPERBYK 182, DISPERBYK 184, DISPERBYK 190, and DISPERBYK 2155 (available from BYK Japan KK); EFKA-46, EFKA-47, EFKA-48 and EFKA-49 (available from EFKA Chemicals); Polymer 100, Polymer 120, Polymer 150, Polymer 400, Polymer 401, Polymer 402, Polymer 403, Polymer 450, Polymer 451, Polymer 452, Polymer 453 (available from EFKA Chemicals), Ajisper PB711, Ajisper PA111, Ajisper PB811 and Ajisper PW911 (available from AJINOMOTO Co. Ltd.); Flowlen DOPA-15B, Flowlen DOPA-22, Flowlen DOPA-17, Flowlen TG-730W, Flowlen G-700 and Flowlen TG-720W (available from KYOEISHA CHEMICAL Co. Ltd.) and the like. Among them, preferred are SOLSPERSE 11200, SOLSPERSE 13940, SOLSPERSE 16000, SOLSPERSE 17000, SOLSPERSE 18000, SOLSPERSE 28000, DISPERBYK 142 or DISPERBYK 2155 from the viewpoints of low-temperature sintering and dispersion stability.

A content of the polymer dispersant is preferably 0.1 to 15 mass%. When the content of the polymer dispersant is 0.1% or more, the dispersibility of the obtained bonding composition becomes better, but if the content is too large, the binding property becomes poor. For this reason, the content of the polymer dispersant is more preferably 0.03 to mass%, more preferably 0.05 to 2 mass%.

The content of the organic component adhering to the metal particle in the binder composition of this embodiment is preferably 0.5 to 50 mass%. When the content of the organic component is 0.5 mass% or more, the storage stability of the obtained metal-bonding composition tends to be better, and when it is 50 mass% or less, the conductivity of the metal-bonding composition tends to better be.

The content of the organic component is more preferably 1 to 30 mass%, more preferably 2 to 15 mass%.

As the composition ratio (mass) when using the amine and the carboxylic acid in combination, it may be optionally selected within the range of 1/99 to 99/1, and is preferable 20/80 to 98/2, more preferably 30/70 to 97/3. As the amine or carboxylic acid, several kinds of amines or carboxylic acids can be used.

For example, the metal particles may be prepared by mixing a source of metal ion of a dispersant and then reducing. By optimizing the amounts of the added dispersant and a reducing agent or the like, it is possible to control the amount of the organic component.

For controlling an amount of the organic component adhering to the metal particle, a heat treatment for the metal particles, washing by acid (sulfuric acid, hydrochloric acid and nitric acid, etc.), washing by a fat-soluble organic solvent such as acetone or methanol and the like can be used. During washing, by applying an ultrasonic wave, the organic component can be removed more efficiently.

(1-3) Other organic components and the like

In the binder composition of this embodiment, an unsaturated hydrocarbon may be contained.

Examples of the unsaturated hydrocarbon include ethylene, acetylene, benzene, acetone, 1-hexene, 1-octene, 4-vinylcyclohexene, cyclohexanone, terpene-based alcohol, allyl alcohol, oleyl alcohol, 2-paltoleic acid, petroselinic acid, oleic acid, elaidic acid, thiocyanic acid, ricinoleic acid , Linoleic acid, linoic acid, linolenic acid, arachidonic acid, acrylic acid, methacrylic acid, bile acid, salicylic acid and the like.

Among them, an unsaturated hydrocarbon having a hydroxyl group is preferable. The hydroxyl group is easy to coordinate with the surface of the metal particles to inhibit coagulation of the metal particles. Examples of the unsaturated hydrocarbon having hydroxyl group include a terpene-based alcohol, allyl alcohol, oleyl alcohol, thiocyanic acid, ricinoleic acid, bile acid, salicylic acid and the like. Preferred is an unsaturated fatty acid having a hydroxy group such as thiocyanic acid, ricinoleic acid, bile acid, salicylic acid and the like.

The above unsaturated hydrocarbon is preferably ricinoleic acid. Ricinoleic acid has a carboxyl group and hydroxyl group and adsorbed on the surface of the metal particles to uniformly disperse the metal particles, and accelerates the fusion of the metal particles.

In the binding composition of this embodiment, within the scope that the effect of this invention is not impaired, for further addition of functions such as appropriate viscosity, adhesiveness, drying properties or printing ability according to the purposes of use, optional components such as a dispersing medium, an oligomer component, e.g. Role of a binder, resin component, organic solvent (a portion of the solid may be dissolved or dispersed), surfactant, thickener, or surface tension adjustor. Such optional components are not particularly limited.

As the dispersing medium among the optional components, various components within the scope are usable so that the effects of this invention are not impaired, and examples include a hydrocarbon, alcohol and the like.

Examples of the hydrocarbon include an aliphatic, alicyclic, cyclic hydrocarbon and the like, and they may be used alone or in combination of two or more.

Examples of the aliphatic hydrocarbon include a saturated or unsaturated aliphatic hydrocarbon such as tetradecane, octadecane, heptamethylnonane, tetramethylpentadecane, hexane, heptane, octane, nonane, decane, tridecane, methylpentane, normal paraffin or isoparaffin, and the like.

Examples of the cyclic hydrocarbon include toluene, xylene and the like.

Further, examples of the alicyclic hydrocarbon include limonene, dipentene, terpinene, terpinene (also referred to as terpinine), nesol, cinnamon, orange flavor, terpinolene, terpinolene (also referred to as terpinoline), phellandrene, menthadiene, tereben, dihydrocymen, molybdenum, isoterpines (also referred to as isoterpinine), critemes, gums, cajeps, oilimines, pinene, terebin, menthan, pinane, terpene, cyclohexane and the like.

The alcohol is a compound containing one or more OH groups in the molecular structure, and examples include an aliphatic, cyclic or alicyclic alcohol, and they may be used alone or in combination of two or more. Part of the OH groups may be converted into an acetoxy group or the like within a range such that the effect of this invention is not impaired.

Examples of the aliphatic alcohol include a saturated or unsaturated C _6-30 aliphatic alcohol such as heptanol, octanol (such as 1-octanol, 2-octanol or 3-octanol), decanol (such as 1-decanol), lauryl alcohol, tetradecyl alcohol, cetyl alcohol, 2- Ethyl 1-hexanol, octadecyl alcohol, hexadecanol or oleyl alcohol.

Examples of the cyclic alcohol include cresol, eugenol and the like.

Examples of the alicyclic alcohol include a cycloalkanol such as cyclohexanol; Terpene alcohol (monoterpene alcohol or the like) such as terpineol (including α, β and γ isomers or any mixture thereof) or dihydroterpeneol, dihydroterpineol, myrtenol, sobrerol, menthol, carveol, perillyl alcohol, pinocarbeol, sobrerol, verbenol and the like.

The content in the presence of a dispersing medium in the binder composition of this embodiment can be adjusted according to the desired properties such as viscosity, and the content of the dispersion medium in the bonding composition is preferably 1 to 30 mass%. When the content of the dispersing medium is 1 to 30 mass%, an effect for adjusting the viscosity within the range can be obtained so that it is easy for the composition to be suitable for binding. The content of the dispersing medium is more preferably 1 to 20 mass%, more preferably 1 to 15 mass%.

Examples of the resin component include a polyester-based resin, polyurethane-based resin such as blocked polyisocyanate, polyacrylate-based resin, polyacrylamide-based resin, polyether-based resin, melamine-based resin, terpene-based resin and the like, and these may be used alone or in combination of two or more.

Examples of the organic solvent without the solvents exemplified as dispersion media include methyl alcohol, ethyl alcohol, n-propyl alcohol, 2-propyl alcohol, 1,3-propanediol, 1,2-propanediol, 1,4-butanediol, 1,2,6 Hexanetriol, 1-ethoxy-2-propanol, 2-butoxyethanol, ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol having a weight average molecular weight within the range of 200 or more or 1000 or less, propylene glycol, dipropylene glycol, tripropylene glycol, polypropylene glycol having a molecular weight of Weight average within the range of 300 or more or 1000 or less, N, N-dimethylformamide, dimethyl sulfoxide, N-methyl-2-pyrrolidone, N, N-dimethylacetamide, glycerol, acetone and the like, and these may be used alone or in combination of two or more can be used.

Examples of the thickener include a clay material such as clay, bentonite or hectorite, an emulsion such as a polyester-based emulsion resin, an acrylic-based emulsion resin, a polyurethane-based emulsion resin or a blocked isocyanate, a cellulose derivative such as methyl cellulose, carboxymethyl cellulose, Hydroxyethylcellulose, hydroxypropylcellulose, hydroxypropylmethylcellulose, a polysaccharide such as xanthan gum or guar gum and the like, and these may be used alone or in combination of two or more.

Furthermore, a surfactant other than the above organic components may be added. In a metal dispersion of a multicomponent solvent system, roughness of the coating surface due to a difference in volatile rate upon drying under the influence of the solid content may easily occur. These disadvantages are controlled by adding an additive to the bonding composition of this embodiment, and a bonding composition capable of forming a uniform conductive coating film can be obtained.

The surfactant usable in the present invention is not particularly limited, but one of an anionic, cationic or nonionic surfactant is usable, and examples include Alkylbenzenesulfonate, quaternary ammonium salt and the like. Because an effect can be obtained with a small amount of additive, a fluorine-based surfactant is preferred.

As a method of adjusting the amount of the organic component within a certain range, the adjustment by heating is easier. The amount of the organic component added in the production of metal particles can be adjusted. The cleaning conditions and the number after metal particle adjustment can be changed. The heating may be carried out in an oven or evaporator and it may be carried out under reduced pressure. When carried out under normal pressure, the heating can be carried out even in the atmosphere or in an inert atmosphere. In addition, for an accurate adjustment of an amount of the organic component, the above amine (and carboxylic acid) may later be added.

The viscosity of the binder composition of this invention should be arbitrarily set within a range such that the effects of this invention are not impaired, and for example, it should be within the viscosity range of 0.01 to 5000 Pa · S, and the viscosity range of 0.1 to 1000 Pa · S is more preferable, and the viscosity range of 1 to 100 Pa · S is particularly preferable. The adjustment within the viscosity range allows the use of a broad process as a method of applying a composition for bonding to the substrate.

As a method of applying the binder composition to the substrate, any method may be arbitrarily selected and used, for example, dipping, screen printing, spraying method, bar code method, spin coating method, ink jet method, dispensing method, brush application method, casting method, flexo method, gravure printing method, offset method. Method, transfer method, hydrophilic / hydrophobic method and syringe method and the like.

The viscosity can be adjusted by adjusting the particle size of the metal particles, adjusting the content of an organic substance, adjusting the additive amounts of a dispersing medium and other components, adjusting a mixing ratio of each component, adding a thickener, and the like. The viscosity of the binding composition can be measured, for example, with a cone-plate viscometer (for example Leometer MCR301, manufactured by Anton Paar).

(2) Production of the binding composition

For producing the binder composition of this invention, it is necessary to prepare and mix the inorganic particles in which the metal particles adhere on at least a part to the surface thereof as a main component and the other components.

The inorganic particles in which the metal particles adhere to at least a part thereof can be obtained by synthesizing the metal particles in the presence of the inorganic particles having an average particle size (P _L ) of 1 to 20 μm. When silver particles are used as the inorganic particle and fine silver particles adhere to the surface of the silver particle, the desired inorganic particle can be suitably obtained by mixing a commercially available micro-sized silver particle, silver oxalate and an amine, etc., and reaction in a thermostatic container.

A method for producing the metal particles coated with the organic component is not particularly limited, and for example, a method is used in which a dispersion containing the metal particles is prepared and then the dispersion is washed. A process step for preparing the dispersion containing the metal particles is, for example, a process in which metal salt (or metal ions) dissolved in a solvent is to be reduced, and as a reduction process, a process based on a chemical reduction process should be used.

The metal particles coated with the above organic component can be prepared by reducing a starting material solution (a part of the component need not be dissolved but may be dispersed) comprising the metal salt of the metal forming the metal particles, an organic substance as a dispersant and a solvent (basically an organic system such as toluene, but water may be included). By the reduction, the metal particle in which the organic component adheres to at least a part of the metal particle can be obtained.

As the starting material for obtaining the metal particles coated with the organic substance, various known metal salts or their hydrates can be used, and examples include Silver salt such as silver nitrate, silver sulfate, silver chloride, silver oxide, silver acetate, silver oxalate, silver formate, silver nitrite, silver chlorate or silver sulfide; a gold salt such as chloroauric acid or potassium potassium chloride, gold sodium chloride, a platinum salt such as chloroplatinic acid, platinum chloride, platinum oxide or potassium chloroplatinate; a palladium salt such as palladium nitrate, palladium acetate, palladium chloride, palladium oxide or palladium sulfate; and the like, but are not limited thereto as long as they can be dissolved and reduced in a suitable solvent. Further, they may be used alone or in combination of two or more.

The method for reducing the metal salts in the raw material solution is not particularly limited, and examples include a method using a reducing agent, a method by irradiating a light such as ultraviolet rays, electron beams, ultrasonic waves, thermal energy and the like. Among them, in view of the easy operation, a method using the reducing agent is preferable.

Examples of the reducing agent include an amine compound such as dimethylaminoethanol, methyldiethanolamine, triethanolamine, phenidone or hydrazine; a hydrogen compound such as sodium borohydride, hydrogen iodide or hydrogen gas; an oxide such as carbon monoxide, sulphurous acid; a low valence metal such as ferrous sulfate, ferric oxide, ferrifumarate, ferrolactate, ferrioxalate, ferrisulfide, tin acetate, tin chloride, tin diphosphate, tin oxalate, tin oxide or tin sulfate; a sugar such as ethylene glycol, glycerin, formaldehyde, hydroquinone, pyrogallol, tannin, tannic acid, salicylic acid or D-glucose; and the like, but are not limited thereto as long as it can be dissolved and reduced in an appropriate solvent. By using the above reducing agent, the reduction reaction can be accelerated by adding light and / or heat.

As a specific method for producing the metal particles coated with the organic substance by using the metal salt of the organic component, the solvent and the reducing agent, examples include a method in which the metal salt is dissolved in an organic solvent (for example, toluene and the like). for preparing a solution of the metal salt, and adding an organic substance as a dispersant to the solution of the metal salt, and then gradually adding the solution to dissolve the reducing agent, and the like.

In the dispersion containing the metal particles coated with the organic component as a dispersant obtained in the above-described manner, an electrolyte concentration of the entire dispersion tends to be higher because of being counter ions of metal salt, a remainder of the metal salt Reductant and the other dispersant than the metal particles. Because the dispersion has high conductivity in such a state, the metal particles tend to coagulate and precipitate easily. Alternatively, even if the metal particles are not precipitated, if the counter-ions of the metal salt, a remainder of the reducing agent or the dispersant remains in an amount which is an excess to the amount necessary for dispersing, and there is a risk that the conductivity is made worse. Then, the metal particles coated with the organic substance can be surely obtained by washing the solution containing the metal particles to remove excess residues.

As the washing method, examples include a method in which steps of leaving the dispersion containing the metal particles coated with the organic component for a certain period of time and adding an alcohol (such as methanol) to stir again after the generated supernatant is removed, and allowing the mixture to stand for a certain period of time further and then removing the generated supernatant several times; a method in which centrifugal separation is performed instead of the above standing; a method in which desalting is performed using an ultrafiltration unit, ion exchange apparatus or the like. The metal particles coated with the organic component of this invention can be obtained by such washing to remove the organic solvent.

The binder composition is obtained by mixing the inorganic particles, the metal particles coated with the organic component, and the other components. The method for mixing is not particularly limited and may be performed according to conventionally known methods using a stirrer or mixer. The mixture may be stirred using a spatula or the like, or an ultrasonic homogenizer with appropriate discharge may be used.

The adjustment of an amount of the organic substance and the weight reduction rate is not particularly limited, but easily adjusted by heating. This can be adjusted by Adjusting an amount of an organic substance added in the production of the metal particles. The washing conditions and the number of washes after adjustment of the metal particles can be changed. Heating may be performed with an oven, evaporator or the like. The heating temperature should be within the range of 50 to 300 ° C, and the heating time should be several minutes to several hours. The heating can be carried out under reduced pressure. An amount of an organic substance may be adjusted at a low temperature by heating under reduced pressure. When heated under normal pressure, it is possible to heat even in the atmosphere or in an inert atmosphere. For the fine adjustment of the amount of the organic substance, amine or carboxylic acid may be added later.

The organic component contained in the binder composition and the amount thereof can be confirmed by measurement using, for example, TG-DTA / GC-MS available from Rigaku Corporation. The measurement conditions can be optionally set, and for example, the TG-DTA / GC-MS measurement can be performed when a sample of 10 mg is kept from room temperature to 550 ° C in the atmosphere (temperature increase rate 10 ° C / min).

Solid particles can be obtained by washing the metal particles with methanol, centrifuging (for example, 3300 rpm for 2 minutes), reprecipitating, removing the supernatant liquid, and then drying under reduced pressure. By conducting the TG-DTA / GC-MS measurement with the obtained solid particles, the organic component adhering to the surface of the metal particles and their amount can be determined.

(3) Binding method

By using the binder composition of this invention, the high shear strength and reliability in bonding parts under heating can be obtained. The bonding reliability means that the mechanical properties and the like of the bonded body can be maintained for a long period of time, and for example, it means that even after a thermal cycle is imposed for several times, the mechanical properties and the like of the bonded body can not be easily lowered.

According to an example of the bonding method by using the bonding composition of this invention, a metal body as a first part to be bonded and a metal body as a second bonding part may be applied by a binder composition applying step, wherein the bonding composition is applied between the first and second metal bodies and a bonding step in which the bonding composition applied between the first and second metal bodies is sintered at a desired temperature (for example, 300 ° C or less) for bonding (formation of the bonding layer). In this case, a pressure may be imposed, but a sufficient bonding strength can be obtained without a particular additional pressure, and this is one of the advantages of this invention. During sintering, the temperature can be gradually increased and decreased. Further, it is also possible to previously apply a surfactant, a surface activating agent or the like on surfaces of the parts to be bonded.

The inventor of this invention has found, as a result of the intensive study, that, when using the binder composition of this invention as the binder composition in the binder composition applying step, the first and second metal bodies (forming a dense bonding layer) having a high bonding strength can be bonded to each other, and the obtained bonded body has a high binding reliability.

The "application" of the binding composition of this invention is a concept comprising a case for planar application and another case for linear application (drawing) of the binding composition. It is possible that the configuration of a coating film of the binder composition in the state before application and sintering by heating is desired. In the bonded body of this invention after sintering by heating, the binder composition is a concept comprising both a planar and a linear bonding layer, and the linear and planar bonding layers may be continuous or discontinuous or have a continuous or discontinuous region.

The first and second metal bodies usable in the present invention should be those in which the binder composition is applied and which is sintered and bonded by heating and there is no particular limitation, but parts having a thermal resistance to the extent that no damage occurs at a temperature of bonding are preferred.

Many materials can be used as materials that make up such a metal body. The reason why the metal body is preferable is that it is excellent in thermal resistance and affinity with the binder composition of this invention when the inorganic particles are metal. Parts to be bound may have various shapes such as plate type or strip type, and may be rigid or flexible. The thickness of the substrate can also be optionally selected. For the purpose of improving the adhesion property or adhesiveness or other purposes, a part where a surface layer is formed or a part where a surface treatment such as hydrophilic treatment is performed may be used.

In the method of applying the binder composition to the parts to be bonded, it is possible to use various methods, and as described above, it is possible to optionally employ a method selected from dipping, screen printing, spraying, barcode, spin coating, ink jet, dispensing , Transfer method, brush application method, casting method, flexo method, gravure method and syringe method.

The coating film after application as mentioned above is sintered by heating at, for example, 300 ° C or less within the range so that the parts to be bonded are not damaged, and the bonded body of this invention can be obtained. In this embodiment, as mentioned above, because the binder composition of this invention is used, a bonding layer having excellent adhesion with respect to the parts to be bonded can be obtained, and strong bonding strength can be obtained more securely. The thickness of the bonding layer can be easily controlled by the thickness of the coating film.

In this embodiment, when the binder composition contains a binder component, in view of enhancing the strength of the binder layer and improving the bond strength between the parts to be bonded, the binder component is also baked, but depending on the circumstances, a baking state is controlled and the binder component can pass through Adjusting the viscosity of the binding composition for use for various printing processes as a primary purpose of the binding component are removed.

The method of sintering is not particularly limited, but for example, the parts to be bonded may be bonded by sintering to adjust the temperature of the binding composition applied or mounted on the parts to be bonded, for example, 300 ° C or less, for example, by a conventionally known furnace or the like is used. The lower limit of the temperature for sintering is not necessarily limited, and it is preferable that it is a temperature that allows the bonding of the parts to be bonded, and is a temperature within the range that the effect of this invention is not impaired. In the binder composition after the above sintering, it is better for the highest possible binder thickness to have the remainder of the organic substance being very small, but a proportion of the organic substance may remain within the scope that the effect of this invention is not impaired.

In the bonding method of the metal body of this invention, it is preferable that the binding atmosphere is the atmosphere or a mixed atmosphere of air and nitrogen, and when the inorganic particle and the organic component are within TMA within the range of room temperature to 500 ° C under such binding atmosphere is measured, the binding temperature is adjusted so that a rate of dimensional change from room temperature is -1.0 to 1.0%.

In measuring the inorganic particle and the organic component by TMA within the range of room temperature to 500 ° C under such a binding atmosphere, by setting the rate of dimensional change from room temperature to -1.0% or more, the adhesion to the interface of the body to be bound can be ensured even when the binding is performed without pressure, and by setting to 1.0% or less, the residual stress caused by the heat history in the bonded body can be reduced.

In the bonding method of the metal body of this invention, it is preferable that the bonding temperature be raised to a temperature at which the maximum exothermic peak is generated or at a higher temperature is set when the inorganic particle and the organic component are measured by TG-DTA within the range of room temperature to 500 ° C below the binding atmosphere.

By setting the bonding temperature to a temperature at which the maximum exothermic peak is generated or more, sintering for bonding can proceed.

Further, the binder composition of this invention contains the organic substance, but unlike conventional ones using the thermosetting such as an epoxy resin, bonding strength after sintering is not obtained due to the action of the organic substance, but sufficient bonding strength is obtained by fusion of the fused metal particles receive. Thus, after bonding, even if the binder composition is placed in such an environment for use that a temperature is higher than a binding temperature and the residual organic substance is destroyed or decomposed and disappears, the bonding strength never deteriorates, and therefore it is excellent in terms of thermal resistance.

According to the binder composition of this invention, because bonding can be realized with a bonding layer which develops high conductivity, even by sintering by heating at a low temperature, for example, about 300 ° C, the bonding part can be bonded with relatively weak heat , Further, a sintering time is not particularly limited and should be a sintering time for allowing the parts to be bonded at the sintering temperature.

In this invention, to further enhance the adhesion with the parts to be bonded and the bonding layer, the surface treatment of the parts to be bonded can be carried out. Examples of the surface treatment include a dry treatment such as corona treatment, plasma treatment, UV treatment or electron beam treatment; a method in which a primary layer and a conductive paste-receiving layer are previously formed on the substrate, and the like.

(4) metal-bound body

The metal-bonded body of this invention can be produced by using the binding composition and the binding method. The metal-bonded body of this invention is a metal-bonded body in which the surfaces of two metal bodies are bonded by using the binder composition of this invention and one of the bonding layer of the metal-bonded body is 30 to 150 μm. Because the bonding layer is composed of the inorganic particles and the metal particles, the melting point after sintering is the same as the bulk material as opposed to a brazing material. Therefore, as compared with the bonding layer formed by a brazing material, hot-cold shock reliability at a higher temperature can be obtained.

When the thickness of the bonding layer is 30 to 150 μm, it is possible to make the bonding layer dense and to relax the thermal stress due to a difference in thermal expansion coefficient of the body to be bonded, and the metal bonded body has a high binding reliability.

The representative embodiments of this invention are explained, but this invention is not limited to these examples at all. Hereinafter, in the Examples and Comparative Examples, the binder composition and the metal-bonded body are further explained by using the compound of this invention, but this invention is not limited to the examples.

Examples

<< Example 1 >>

0.05 g of SOLSPERSE 16000, which is a polymer dispersant, 8.0 g of hexylamine (special class grade chemical, available from Wako Pure Chemical Industries, Ltd.) and 0.40 g of dodecylamine (first grade chemical, available from Wako Pure Chemical Industries, Ltd.) were mixed and the mixture was stirred sufficiently with a magnetic stirrer. With further stirring, 6.0 g of silver oxalate and 10.0 g of silver particles (average particle size in the catalog: 3 μm) available from Mitsui Kinzoku Co. Ltd. were added, and the mixture was thickened. The resulting thickened substance was placed in a constant temperature bath at 120 ° C and reacted for about 15 minutes.

To replace the dispersion medium of a suspension, after adding 10 ml of methanol and stirring, silver particles whose surface was coated with the fine silver particles were precipitated and separated by centrifugal separation, and then the supernatant liquid was removed. After repeating the substitution treatment, 1 g as a dispersion medium was added to 15 g of silver particles in which the surface was coated with the fine silver particles, and stirred to obtain the binder composition 1. The following evaluation experiments were conducted on the binder composition. The results are shown in Table 1.

[Evaluation Test]

(1) Measurement of Average Particle Size (P _L ) of Inorganic Particles and Particles (P _S ) of Metal Particles

A small amount of the binding composition 1 was diluted with 10 ml of toluene, (P _L ) was measured according to the dynamic light scattering method (DLS) with LB-550 available from HORIBA Ltd. (P _S ) was measured by synthesizing a metal particle without adding the silver particles.

(2) Measurement of the crystallite diameter (C _L ) of the inorganic particle and crystal diameter (C _s ) of the metal particle

With respect to the binder composition 1, the diameter was measured according to the wide-angle X-ray diffraction method with RINT-Ultima III available from Rigaku Corporation. The measurement was made in the region where 2θ was 30 to 80 °, and half the bandwidth at about 38 ° (111 plane) having the largest magnitude in the obtained diffraction spectrum was used in the above Scherrer equation for calculation of the crystallite diameter (C _L ). (C _S ) was measured by synthesizing a metal particle without adding the silver particles.

(3) Binding reliability test

A gold-plated alumina substrate (20 mm square) was compacted with the binder composition 1 by using a metal mask (plate thickness 70 μm) in the form of a 5 mm square, and thereon was placed a gold-plated silicon chip (bottom area 5 mm × 5 mm). The obtained laminated article was placed in a normal temperature socket furnace and the sintering treatment was carried out by heating at 300 ° C for 30 minutes. During the sintering treatment, a pressure of 0.5 MPa was imposed. After natural cooling, the laminated article (metal-bonded body) was taken out. The metal-bonded body was put in a hot-cold influence test machine (JTS-615-64A, available from FUTEC Inc.), the hot-cold test was conducted under the condition that one cycle was constituted by holding at -40 ° C and 250 ° C for 30 minutes each, and was then taken out after an optional number of cycles. Thereafter, the bond strength was measured by using a binding tester (Model: PTR-1101, available from RHESCA Corporation), and when the bond strength was lowered after 500 cycles with respect to 0-cycle bond strength, the evaluation was (x), and if not degraded, was the evaluation (O). The thickness of the bonding layer was 50 μm.

(4) Measurement of the cavity ratio

With respect to a metal bonded body produced under the same sintering conditions as in (3) above except that the pressure in the sintering treatment was not imposed, a void ratio was evaluated using an ultrasonic test equipment (μ-SDS) available from KJTD Co., Ltd. under the conditions of the sample: 80 MHz, φ 3 mm, PF = 10 mm. The measurement was made by setting lightly so that the reflection peak at the bonding interface was the highest, at a material sound velocity = Cu: 4800 mm / s. The void ratio is obtained by setting a threshold of the reflectance to 55%, and when the reflectance is more than the threshold, it is evaluated as a void.

<< Example 2 >>

8.0 g of 3-ethoxypropylamine (special class grade chemical, available from Wako Pure Chemical Industries, Ltd.) and 0.40 g of dodecylamine (first grade chemical, available from Wako Pure Chemical Industries, Ltd.) were mixed and the mixture sufficiently stirred with a magnetic stirrer. With further stirring, 6.0 g of silver oxalate and 10 g of silver particles (reduced powder, D50 = 1.5 μm), Available from Mitsui Kinzoku Co., Ltd. added and the mixture thickened. The resulting thickened substance was placed in a constant temperature bath at 120 ° C and reacted for about 15 minutes. To replace the dispersing medium of a suspension, after adding 10 ml of methanol and stirring, silver particles in which the surface was coated with the fine silver particles were precipitated and separated by centrifugal separation, and then the supernatant liquid was removed. After repeating the operations again, 1 g of tridecanol dispersion medium was added to the 15 g of the silver particles in which the surface was covered with the fine silver particles, and stirred to obtain the binder composition 2. The following evaluation tests were conducted on the binder composition. The results are shown in Table 2.

[Evaluation Test]

(1) Measurement of bond strength

A gold-plated copper substrate (20 mm square) was coated with the binder composition 2 using a metal mask in the form of 5 mm square, and then a gold-plated Si chip (bottom surface 5 mm x 5 mm) was laminated. The obtained laminated article was placed in a reflow oven (available from Shinapex Co., Ltd.), and the sintering treatment was conducted under the conditions that a total time period from the temperature elevation to the taking out in the atmosphere was 60 minutes, and the highest temperature was 230 ° C ° C. The sintering treatment was carried out without pressure. After taking out the laminated article, the bonding strength test was carried out at normal temperature using a binding tester (RHESCA Corporation).

(2) Measurement of the Cavity Ratio

With respect to a laminated article produced except that the pressure in the sintering treatment was not imposed, a cavity was evaluated using an ultrasonic testing machine available from KJTD Co., Ltd. (Sample of 80 MHz, φ 3 mm, PF = 10 mm). The measurement was carried out by lightly adjusting so that the reflection peak at the bonding interface was the highest, at a material velocity = Cu: 4800 mm / s. The void ratio is obtained by setting a threshold of the reflectance as 55%, and when the reflectance is greater than the threshold, it is evaluated as a void.

(3) high-temperature reliability

The metal-bonded body sintered in the above section (1) was placed in a hot-cold influence test machine (available from FUTEC Inc.), and the hot-cold test was conducted under the condition that one cycle was constituted Hold at -40 ° C and 200 ° C for 10 minutes each and then take out after an optional number of cycles. If the void ratio after 20 cycles was remarkably increased with respect to the bond strength at cycle 0, the evaluation is x, if slightly increased, the evaluation is Δ and if nothing changed, the evaluation is O.

(4) High temperature reliability of non-plated Cu substrate

A non-plated and an oxygen-free copper substrate (20 mm square) was coated with the binding composition 1 by using a metal mask in the form of 5 mm square and thereon was placed a gold-plated Si chip (bottom area 5 mm × 5 mm). laminated. The obtained laminated article was placed in a reflow oven (available from Shinapex Co., Ltd.), and the sintering treatment was conducted under the condition that a total period of time from the temperature elevation to the removal while nitrogen gas flowed through was 60 minutes, and the highest temperature was 250 ° C. An oxygen concentration after sintering was 0.1%. The sintering treatment was carried out without pressure. After taking out the laminated article, the bond strength test and the hot-cold hold test were carried out at normal temperature using a binding tester (RHESCA Corporation). The hot-cold hold test was conducted by using the hot-cold hold test machine available from FUTEC Inc. on the condition that one cycle was constituted by holding at -40 ° C and 200 ° C for 10 minutes each, and then the removal after the optional number of cycles. If the void ratio after 20 cycles was remarkably increased with respect to the bond strength at cycle 0, the evaluation is x, if it increased a little, the evaluation is Δ, and if nothing changed, the evaluation is O.

(5) Measurement of rate of dimensional change

A sample prepared by introducing 1 g of Binding Composition 1 containing no dispersing medium into a 5 x 20 mm die and pressed at a pressure of 20 kN was measured using THA (TMA8310 available from Rigaku Corporation ) rated. The measurement was conducted in the atmosphere at a temperature elevation rate of 5 ° C / min from room temperature to 500 ° C, and the rate of change of the length of the sample from room temperature was used as a rate of dimensional change.

<< Example 3 >>

A binder composition 3 was prepared in the same manner as in Example 2 except that 3-methoxpropylamine (first grade chemical available from Wako Pure Chemical Industries, Ltd.) was used in place of 3-ethoxypropylamine, and the various evaluations became carried out. The results are shown in Table 2.

<< Example 4 >>

A binder composition 4 was prepared in the same manner as in Example 3 except that butylcarbitol acetate was used in place of tridecanol, and the various evaluations were carried out. The results are shown in Table 2.

<< Example 5 >>

A binder composition 5 was prepared in the same manner as in Example 3 except that silver particles (reduced powder, D50 = 3.0 μm) available from Mitsui Konzoku Co., Ltd. were used in place of silver particles of 1.5 μm and the various evaluations were carried out. The results are shown in Table 2.

<< Example 6 >>

A binder composition 6 was prepared in the same manner as in Example 3 except that the oxygen concentration after sintering was 1% by regulating the flow rate of nitrogen gas in the binding to the Cu substrate, and the various evaluations were carried out , The results are shown in Table 2.

<< Example 7 >>

A binder composition 7 was prepared in the same manner as in Example 3 except that the oxygen concentration after sintering was 5% by regulating the flow rate of nitrogen gas in the binding to the Cu substrate, and the various evaluations were carried out , The results are shown in Table 2.

<< Example 8 >>

A binder composition 8 was prepared in the same manner as in Example 2 except that the maximum temperature in the sintering treatment was 250 ° C, and the various evaluations were conducted. The results are shown in Table 3.

<< Comparative Example 1 >>

A comparative binder composition was prepared in the same manner as in Example 1 except that silver particles having an average particle size of the catalog value of 0.3 μm were used in place of the silver particles having an average particle size of the catalog value of 3 μm, and the various evaluations have been performed. The results are shown in Table 1.

<< Comparative Example 2 >>

0.40 g of SOLSPERSE 16000, which is a polymer dispersant, 2.0 g of hexylamine ( First grade chemistry available from Wako Pure Chemical Industries, Ltd.) and 0.40 g of dodecylamine (first grade chemical available from Wako Pure Chemical Industries, Ltd.) were mixed and the mixture was sufficiently stirred with a magnetic stirrer. With further stirring, 6.0 g of silver oxalate was added and the mixture was thickened. The resulting thickened substance was placed in a constant temperature bath of 100 ° C and reacted for about 15 minutes.

To replace the dispersion medium of a suspension, after addition of 10 ml of methanol and stirring, silver particles were precipitated and separated by centrifugal separation, and then the supernatant solution was removed. To the obtained fine silver particles as a dispersion medium, 1 g of dihydroterphenyl acetate was added and stirred to obtain the silver colloid dispersion. For removing impurities such as organic and inorganic components adhering to the silver particles (average particle size in the catalog: 3 μm) available from Mitsui Kinzoku Co., Ltd., 10 g of silver particles were weighed and poured into a 50 ml aqueous solution containing was prepared by diluting 0.1 ml of 35% nitric acid to 100 ml by ion exchange water. After sonication, the silver particles were precipitated by centrifugation and then a supernatant was removed. Thereafter, methanol was removed by Diphragma pump, the silver particles thus obtained and 0.5 g of dihydroterpinyl acetate were added to the silver colloid dispersion to obtain the comparative binder composition 2. The same evaluation tests as in Example 1 were carried out. The results are shown in Table 1.

<< Comparative Example 3 >>

A comparative binder composition 3 was prepared in the same manner as in Example 2 except that silver particles (reduced powder, D50 = 8.5 μm) available from Mitsui Kinzoku Co., Ltd. were used instead of the silver particles of 1.5 μm were used, and the various evaluations were carried out. The results are shown in Table 3. In Table 3, the case where the bonding strength is 20 MPa or more is represented by O, and the case where less than 20 MPa is represented by x. [Table 1] Binding Composition 1 Comparative Binding Composition 1 Comparative binding composition Average particle size PL of the silver particles in the binder composition (μm) 3.5 0.5 0.05 and 3.2 (two peaks, distribution) Average particle size of the silver particles (μm) (catalog value) 3.0 0.3 3 Crystallite diameter C _{L of} the silver particles in the binder composition (nm) 29 25 29 Average particle size PS of the fine silver particles in the binding composition (nm) 45 45 50 Crystallite diameter C _{S of} the fine silver particles in the binder composition (nm) 11 11 12 Presence or absence of the fine silver particles adhering to the surface of silver particles To be available To be available absence High-temperature reliability O X X Void ratio (%) 1 50 20

When using the binder composition 1 containing the particles in which the fine silver particles have an average Particle size of 45 nm adhered to the surface of the silver particles having an average particle size of 3.0 microns, the void ratio is considerably small and is 1%, and a high binding reliability can be obtained. In contrast, in Comparative Binder Composition 1, which adheres the particles in which the fine silver particles having an average particle size of 45 nm adhere to the surface of the small silver particles having an average particle size of 0.3 μm, the void ratio is 50%, and thus, sufficient binding reliability can not be obtained. In the comparative binder composition 2 containing the fine silver particles having an average particle size of 50 nm and the silver particles having an average particle size of 3.0 μm, the fine silver particles did not adhere to the surface of the silver particle, the void ratio is 20%, and thus a sufficient binding reliability can not be obtained.

By using the binding composition 1, the metal-bonded bodies were prepared by varying the thickness of the bonding layer within the range of 10 to 200 μm. The binding reliability test was conducted with respect to the obtained metal-bonded bodies. The results are shown in Table 4. The thickness of the tie layer was controlled by the coating amount of the tie composition 1.

When using the binding compositions 2 to 7 in which the weight gain was observed after the DTA peak, the bonding strength is 20 MPa, the void ratio is low, and good high-temperature reliability can be obtained. Such properties can be obtained not only when the Cu substrate was plated with gold, but also when the Cu substrate was not plated with gold. [Table 3] Example 2 Example 8 Comparative Example 3 Sintering temperature (° C) 230 250 230 Rate of dimensional change (%) 0.13 0.47 1.96 Initial bond strength O O X Initial void ratio (%) 0 0 20 High-temperature reliability O O X

The binder composition 2 and the binder composition 8 which did not contain the dispersing medium show an extremely small rate of dimensional change, and Examples 2 and 8 using the binder compositions 2 and 8, respectively, and the method of bonding the metal-bonded body According to this invention, metal-bonded bodies with high bond strength and high temperature reliability resulted. In contrast, the rate of the voids in Comparative Example 3 is high, and thus a sufficient bonding strength and high-temperature reliability can not be obtained. [Table 4] Thickness of the bonding layer (μm) 10 20 30 50 100 150 200 binding reliability X X O O O O X

When the thickness of the bonding layer is within the range of 30 to 150 μm, high bonding reliability can be obtained. In contrast, when the thickness of the bonding layer is less than 30 μm (10 or 20 μm) or larger than 150 μm (200 μm), the bonding strength is lowered with respect to the hot-cold hold test of 500 cycles, and thus one can sufficient binding reliability can not be obtained.

Claims (5)

A binder composition containing an inorganic particle, an organic component and a dispersing medium, wherein an average particle size and a crystallite diameter of the inorganic particle are 1 to 20 μm and 4 to 40 nm, respectively, and Metal particles having a particle size of 1 to 100 nm adhere to at least a part of the surface of the inorganic particles. The binder composition of claim 1, wherein a particle size of the metal particle is 4 to 400 nm. The binder composition of claim 1 or 2, wherein the metal particle is a silver particle. The binder composition of claim 1 or 2, wherein the inorganic particle is a silver particle. A metal-bonded body comprising two metal bodies bonded by the binder composition of claim 1, wherein a thickness of a bonding layer of the metal-bonded body is 30 to 150 μm.