WO2020017050A1

WO2020017050A1 - Composition, bonding material, sintered compact, assembly, and method for producing assembly

Info

Publication number: WO2020017050A1
Application number: PCT/JP2018/027384
Authority: WO
Inventors: 秀明山岸; 史貴上野; 斉藤　晃一; 雅記竹内; 貴耶山本; 将太梅崎; 洋子坂入
Original assignee: 日立化成株式会社
Priority date: 2018-07-20
Filing date: 2018-07-20
Publication date: 2020-01-23
Also published as: JPWO2020017065A1; JP7238894B2; WO2020017065A1

Abstract

This composition contains a metal component which can undergo transitional liquid-phase sintering. The metal component contains: metal particles A having a melting point higher than 300°C; and metal particles B having a melting point not exceeding 300°C. The void volume X (in cm³) of metal particles A and the density Y (in g/cm³) of the metal particles B, and the mass Z (in g) of metal particles B satisfy the formula: 0.8≤Z/XY≤1.2.

Description

Composition, bonding material, sintered body, bonded body, and method for manufacturing bonded body

The present invention relates to a composition, a bonding material, a sintered body, a bonded body, and a method for manufacturing a bonded body.

(4) Lead-containing alloys (solders) have conventionally been used as means for joining a semiconductor element and a support member when manufacturing a semiconductor device. In recent years, switching to a lead-free solder that does not contain lead or has a reduced lead content has been promoted in consideration of effects on the environment and living bodies.

Various alloy compositions have been studied as lead-free solders, but those containing Sn (tin), Ag (silver) and Cu (copper), which are the mainstream, have a higher melting point than solders containing lead. Since it has properties such as re-melting when placed in an environment at or above the melting point later, handling restrictions are great. In addition, as the speed of semiconductor elements and the degree of integration of semiconductor elements increase, there is a demand for improvement in high-temperature resistance of semiconductor devices. For this reason, there is a demand for the development of a bonding material having excellent low-temperature bonding properties and high-temperature connection reliability.

As a bonding material that has excellent low-temperature bonding properties and high-temperature connection reliability (sinters at low temperatures and has a high melting point after sintering), it is referred to as a transitional liquid phase sintered metal adhesive. A joining material has been proposed (for example, see Patent Document 1, Non-Patent Document 1, and Non-Patent Document 2).

Patent No. 6203493

As described above, as the speed of semiconductor devices and the degree of integration of semiconductor devices increase, there is a demand for a case where the semiconductor devices are exposed to high temperatures. If the thermal conductivity of the bonding material used for the semiconductor element is insufficient, the temperature of the semiconductor device using the bonding material may rise excessively, causing a failure or deterioration.
One embodiment of the present invention has been made in view of the above circumstances, and includes a composition capable of forming a sintered body having excellent thermal conductivity and bonding strength by a transitional liquid phase sintering method, and containing the composition. An object of the present invention is to provide a joining material, a sintered body using the composition, a joined body, and a method for producing the same.

Specific means for achieving the above object are as follows.
<1> A metal component capable of transitional liquid phase sintering is contained, and the metal component includes metal particles A having a melting point higher than 300 ° C. and metal particles B having a melting point of 300 ° C. or lower. A composition in which the void volume X (cm ³ ), the density Y (g / cm ³ ) of the metal particles B, and the amount Z (g) of the metal particles B satisfy the following formula.
0.8 ≦ Z / XY ≦ 1.2
<2> The composition according to <1>, wherein the void volume X of the metal particles A is 50% by volume or less of the apparent volume of the metal particles A.
<3> The composition according to <1> or <2>, wherein the metal particles A include Cu.
<4> The composition according to any one of <1> to <3>, wherein the metal particles B include Sn.
<5> A bonding material containing the composition according to any one of <1> to <4>.
<6> A sintered body of the composition according to any one of <1> to <5>.
<7> A joined body in which the element and the support member are joined via the sintered body according to claim 5.
<8> The composition according to any one of <1> to <4> is applied to at least one of a position where the element is joined to the support member and a position where the device is joined to the support member. Production of a joined body comprising: a step of forming a composition layer; a step of contacting the support member with the element via the composition layer; and a step of heating and sintering the composition layer. Method.

According to one aspect of the present invention, a composition capable of forming a sintered body having excellent thermal conductivity and bonding strength by a transitional liquid phase sintering method, a bonding material containing the composition, and a composition using the composition The present invention provides a sintered body, a joined body, and a method of manufacturing the same.

Hereinafter, embodiments for carrying out the present invention will be described in detail. However, the present invention is not limited to the following embodiments. In the following embodiments, the components (including the element steps and the like) are not essential unless otherwise specified. The same applies to numerical values and their ranges, and does not limit the present invention.
In the present disclosure, the numerical ranges indicated by using “to” include the numerical values described before and after “to” as the minimum value and the maximum value, respectively.
In the numerical ranges described in stages in the present disclosure, the upper limit or lower limit described in one numerical range may be replaced with the upper limit or lower limit of the numerical range described in other stages. . Further, in the numerical range described in the present disclosure, the upper limit or the lower limit of the numerical range may be replaced with the value shown in the embodiment.
In the present disclosure, the content of each component in the composition, when there are a plurality of substances corresponding to each component in the composition, unless otherwise specified, the total of the plurality of substances present in the composition Means content.
In the present disclosure, the particle size of each component in the composition, when there are a plurality of types of particles corresponding to each component in the composition, unless otherwise specified, a mixture of the plurality of types of particles present in the composition Means the value of
In the present disclosure, the term "layer" includes, when observing a region where the layer exists, in addition to a case where the layer is formed over the entire region and a case where the layer is formed only on a part of the region. included.

<Composition>
The composition of the present disclosure contains a metal component capable of transitional liquid phase sintering, wherein the metal component includes metal particles A having a melting point higher than 300 ° C. and metal particles B having a melting point of 300 ° C. or lower, The void volume X (cm ³ ) of the metal particles A, the density Y (g / cm ³ ) of the metal particles B, and the amount Z (g) of the metal particles B satisfy the following formula.
0.8 ≦ Z / XY ≦ 1.2

検討 As a result of the study by the present inventors, it was found that a sintered body obtained from a composition satisfying the above conditions had excellent bonding strength and thermal conductivity. The reason is not necessarily clear, but can be considered as follows.

(4) The metal particles A having a melting point higher than 300 ° C. contained in the composition do not melt in the sintering step and maintain the state of the particles. On the other hand, the metal particles B having a melting point of 300 ° C. or less are melted in the sintering step to fill voids between the metal particles A.

Density of the metal particles B in void volume X (cm ³⁾ of the metal particles A (g / cm ³⁾ obtained by multiplying by the value obtained XY (g), the metal particles to be filled without excess or shortage gap between the metal particles A B corresponds to the amount of the melt.

When the value Z / XY obtained by dividing the amount Z (g) of the metal particles B contained in the composition by XY (g) is 0.8 or more, the gap between the metal particles A in the sintered body is reduced. It is considered that the metal particles B are sufficiently filled with the melt and good bonding strength is achieved. On the other hand, when Z / XY is 1.2 or less, it is considered that contact between the metal particles A in the sintered body is sufficiently ensured, and good thermal conductivity is achieved.

From the viewpoint of bonding strength, the value of Z / XY is preferably equal to or greater than 0.85, and more preferably equal to or greater than 0.9.
From the viewpoint of thermal conductivity, the value of Z / XY is preferably 1.15 or less, and more preferably 1.1 or less.

The void volume X (cm ³ ) of the metal particles A is calculated, for example, from the apparent volume of the metal particles A before mixing with other components (the actual volume of the metal particles + the void volume between the metal particles). Is obtained by subtracting the volume of Specifically, for example, it is determined by subtracting the tap volume (bulk volume) of the metal particles A measured using a graduated cylinder from the bulk volume (constant value) of the metal particles A. When the metal particles A include two or more kinds of metal particles, it is determined by summing the void volumes determined for each metal particle.

From the viewpoint of thermal conductivity, the void volume X of the metal particles A is preferably 50% by volume or less, more preferably 30% by volume or less, and more preferably 25% by volume or less of the apparent volume of the metal particles A. Is more preferable.
From the viewpoint of bonding strength, the void volume X of the metal particles A is preferably 20% by volume or more, more preferably 30% by volume or more, and more preferably 40% by volume or more of the apparent volume of the metal particles A. Is more preferable.

割合 The ratio of the metal particles A in the metal component is not particularly limited as long as the condition of the above formula is satisfied. For example, the content is preferably 50% by mass or more, more preferably 60% by mass or more, and even more preferably 67% by mass or more of the entire metal component.

(Metal components)
The composition of the present disclosure contains a metal component capable of transitional liquid phase sintering.
“Transitional liquid phase sintering” in the present disclosure is also referred to as “Transient Liquid Phase Sintering (TLPS)” and is a liquid obtained by heating a metal interface having a relatively low melting point (low melting point metal) among particles having different melting points. This refers to a phenomenon in which the formation of a metal compound (alloying) by both metals proceeds due to phase transition and reaction diffusion of a metal having a relatively high melting point (high melting point metal) into the liquid phase. By utilizing this phenomenon, it is possible to obtain a sintered body that can be sintered at a low temperature and has a high melting point after sintering.

金属 As a metal component capable of transitional liquid phase sintering, a combination of metals having different melting points (combination of a low melting point metal and a high melting point metal) capable of transitional liquid phase sintering is given. The combination of metals capable of transitional liquid phase sintering is not particularly limited. For example, a combination of a low-melting metal and a high-melting metal is Sn and Cu, a combination of In and Au, and a combination of Sn and Co, respectively. There are certain combinations and combinations of Sn and Ni. The combination of metals capable of transitional liquid phase sintering may be a combination of two metals or a combination of three or more metals.

Metal components capable of transitional liquid phase sintering include metal particles A having a melting point higher than 300 ° C and metal particles B having a melting point of 300 ° C or lower.
From the viewpoint of the bonding strength after sintering, the melting point of the metal particles A is more preferably 500 ° C. or higher, and further preferably 800 ° C. or higher.
From the viewpoint of promoting the transition to the liquid phase during sintering, the melting point of the metal particles B is more preferably 250 ° C. or less.

In one embodiment, the metal component capable of transitional liquid phase sintering may include Cu (melting point: 1085 ° C.) as metal particles A and Sn (melting point: 231.9 ° C.) as metal particles B. May be included. The metal component containing Cu and Sn produces a copper-tin metal compound (Cu ₆ Sn ₅ ) by sintering. Since this generation reaction proceeds at around 250 ° C., sintering by general equipment such as a reflow furnace is possible.

具体 A specific embodiment in the case where the metal component includes the metal particles A and the metal particles B is not particularly limited. For example, the metal particles A and the metal particles B may each be a single metal state, or one or both of the metal particles A and the metal particles B may be in an alloy state. Further, the metal particles A and the metal particles B may contain the same kind of metal element.

In an embodiment, the metal particles A may include Cu, and the metal particles B may include an alloy containing Su. Examples of a case where Sn is in an alloy state include an alloy (SAC) composed of Su, Ag, and Cu, and an alloy composed of Sn and Bi (SnBi). Among them, SAC is preferable. The composition of the SAC is not particularly limited, and examples thereof include Sn-3.0Ag-0.5Cu. In the present disclosure, for example, an alloy represented by Sn-AX-BY indicates that the alloy containing Sn contains A mass% of the element X and B mass% of the element Y in the alloy containing Sn. The melting point (liquid phase transition temperature) of the alloy represented by Sn-3.0Ag-0.5Cu is about 217 ° C.

金属 The metal particles A and the metal particles B contained in the metal component may each be composed of only one kind of metal, or may be composed of two or more kinds of metals. When the metal particle A or the metal particle B is composed of two or more kinds of metals, even if the metal particle is a combination (mixture) of metal particles containing each of the two or more kinds of metals, the two or more kinds of metals are the same metal. It may be contained in the particles or a combination thereof.

構成 The configuration of metal particles containing two or more metals in the same metal particle is not particularly limited. For example, it may be a metal particle composed of an alloy of two or more metals or a metal particle composed of a simple substance of two or more metals. Metal particles composed of a simple substance of two or more metals can be obtained, for example, by forming a layer containing the other metal on the surface of the metal particle containing one metal by plating, vapor deposition, or the like. In addition, the same metal particles are applied to the surface of a metal particle containing one metal by applying particles containing the other metal in a dry manner using a force mainly composed of an impact force in a high-speed airflow to combine the two. Metal particles containing two or more metals therein can also be obtained.

平均 The average particle size of the metal particles is not particularly limited. For example, the average particle size of the metal particles is preferably 0.5 μm to 80 μm, more preferably 1 μm to 50 μm, and still more preferably 1 μm to 30 μm.

平均 The average particle size of the metal particles refers to a volume average particle size measured by a laser diffraction type particle size distribution analyzer (for example, LS {13} 320 type laser scattering diffraction particle size distribution analyzer, Beckman Coulter, Inc.). Specifically, metal particles are added to 125 g of a solvent (terpineol) in a range of 0.01% by mass to 0.3% by mass to prepare a dispersion. About 100 ml of this dispersion is poured into a cell and measured at 25 ° C. The particle size distribution is measured with the refractive index of the solvent being 1.48.

関係 The relationship between the sizes of the metal particles A and the metal particles B is not particularly limited. From the viewpoint of filling the voids between the metal particles A with the molten metal particles B during sintering, for example, the value of the average particle diameter of the metal particles A / the average particle diameter of the metal particles B is preferably greater than 1. More preferably, it is more than 2, more preferably more than 5. The upper limit of the value of the average particle size of the metal particles A / the average particle size of the metal particles B is not particularly limited, but may be, for example, 10 or less.

含有 The content of the metal component in the composition is not particularly limited. For example, the ratio by mass of the metal component to the entire composition is preferably 80% by mass or more, more preferably 85% by mass or more, and even more preferably 88% by mass or more. Further, the ratio by mass of the metal component to the entire composition may be 98% by mass or less. When the ratio based on the mass of the metal component is 98% by mass or less, printability tends to be hardly impaired when the composition of the present disclosure is used as a paste.

(Organic components)
The composition of the present disclosure may further contain an organic component. When the composition contains an organic component, effects such as improvement of printability when the composition of the present disclosure is used as a paste can be obtained.

含有 The content of the organic component in the composition is not particularly limited. For example, the proportion by mass of the organic component in the entire composition is preferably less than 20% by mass, more preferably less than 15% by mass, and even more preferably less than 12% by mass. Further, the ratio by mass of the organic component to the whole composition may be more than 2% by mass. If the proportion based on the mass of the organic component is more than 2% by mass, printability tends to be hardly impaired when the composition of the present disclosure is used as a paste.

(Resin component)
The composition of the present disclosure may contain a resin component as an organic component. When the composition contains the resin component, the voids between the metal components in the sintered product are filled with the resin component, and the stress relaxation property and the like tend to be improved.

樹脂 The resin component contained in the composition may be a thermoplastic resin, a thermosetting resin, or a combination thereof. The resin component may be in the state of a monomer having a functional group capable of causing a polymerization reaction by heating or in the state of a polymer that has already been polymerized.

から From the viewpoint of heat resistance, it is preferable to include a thermosetting resin as a resin component. Examples of the thermosetting resin include a resin having a functional group such as an epoxy group, an acryloyl group, a methacryloyl group, a hydroxy group, a vinyl group, a carboxy group, an amino group, a maleimide group, an acid anhydride group, a thiol group, and a thionyl group. Can be

Specific examples of the thermosetting resin include an epoxy resin, an oxazine resin, a bismaleimide resin, a phenol resin, an unsaturated polyester resin, and a silicone resin. Of these, epoxy resins are preferred.

Specific examples of the epoxy resin, for example, bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, phenol novolak type epoxy resin, cresol novolak type epoxy resin, naphthalene type epoxy resin, biphenol type epoxy resin, Biphenyl novolak type epoxy resins and cycloaliphatic epoxy resins are exemplified. The resin component may be used alone or in combination of two or more.

場合 When the organic component contains a resin component, the ratio of the resin component to the entire organic component is not particularly limited. For example, it may be 0.1% by mass to 50% by mass of the whole organic component.

(Flux component)
The composition of the present disclosure may contain a flux component as an organic component. In the present disclosure, the flux component means an organic component capable of exerting a flux action (an action of removing an oxide film), and its type is not particularly limited. Specific examples of the flux component include a rosin, an activator, a thixotropic agent, and an antioxidant. One type of flux component may be used alone, or two or more types may be used in combination.

Specific examples of rosin include dehydroabietic acid, dihydroabietic acid, neoabietic acid, dihydropimaric acid, pimaric acid, isopimaric acid, tetrahydroabietic acid, and parastolic acid.
Specific examples of the activator include aminodecanoic acid, pentane-1,5-dicarboxylic acid, triethanolamine, diphenylacetic acid, sebacic acid, phthalic acid, benzoic acid, dibromosalicylic acid, anisic acid, iodosalicylic acid, picolinic acid and the like. Can be
Specific examples of the thixotropic agent include 12-hydroxystearic acid, 12-hydroxystearic acid triglyceride, ethylenebisstearic acid amide, hexamethylenebisoleic acid amide, N, N'-distearyladipic acid amide and the like.
Specific examples of the antioxidant include a hindered phenol-based antioxidant, a phosphorus-based antioxidant, and a hydroxylamine-based antioxidant.

場合 When the organic component contains a flux component, the ratio of the flux component to the entire organic component is not particularly limited. For example, it may be 0.1% by mass to 50% by mass of the whole organic component.

(solvent)
The composition of the present disclosure may contain a solvent as an organic component. From the viewpoint of sufficiently dissolving the resin component, the solvent is preferably a polar solvent, and from the viewpoint of preventing drying of the composition in the step of applying the composition, it is preferably a solvent having a boiling point of 200 ° C or higher. It is more preferable that the solvent has a boiling point of 300 ° C. or less in order to suppress generation of voids during sintering.

Examples of such solvents include terpineol, stearyl alcohol, tripropylene glycol methyl ether, diethylene glycol, diethylene glycol monoethyl ether (ethoxyethoxyethanol), diethylene glycol monohexyl ether, diethylene glycol monomethyl ether, dipropylene glycol-n-propyl ether, Alcohols such as dipropylene glycol-n-butyl ether, tripropylene glycol-n-butyl ether, 1,3-butanediol, 1,4-butanediol, propylene glycol phenyl ether, 2- (2-butoxyethoxy) ethanol; Tributylate, 4-methyl-1,3-dioxolan-2-one, γ-butyrolactone, diethylene glycol Esters such as ethyl ether acetate, dipropylene glycol methyl ether acetate, diethylene glycol monobutyl ether acetate and glycerin triacetate; ketones such as isophorone; lactams such as N-methyl-2-pyrrolidone; nitriles such as phenylacetonitrile. it can. The solvent may be used alone or in combination of two or more.

場合 When the organic component contains a solvent, the proportion of the solvent in the whole organic component is not particularly limited. For example, it may be 0.1% by mass to 50% by mass of the whole organic component.

(Method for producing composition)
The method for producing the composition of the present disclosure is not particularly limited. It can be obtained by mixing the components constituting the composition of the present disclosure, and further performing a treatment such as stirring, melting, and dispersion. The apparatus for mixing, stirring, dispersing, and the like is not particularly limited, and includes a three-roll mill, a planetary mixer, a planetary mixer, a rotation-revolution-type stirring apparatus, a grinder, a twin-screw kneader, A thin shear disperser or the like can be used. Further, these devices may be used in appropriate combination. During the above treatment, heating may be performed as necessary.
After the treatment, the maximum particle size of the composition may be adjusted by filtration. Filtration can be performed using a filtration device. Examples of the filter for filtration include a metal mesh, a metal filter, and a nylon mesh.

(Use of the composition)
The composition of the present disclosure is used, for example, as a joining material for joining an element constituting a semiconductor device, an electronic component, or the like and a support member. However, applications of the composition of the present disclosure are not limited to these.

<Joining materials>
The bonding material of the present disclosure contains the composition of the present disclosure. The composition of the present disclosure can be used as a bonding material as it is, or may be used as a bonding material by adding other components as necessary. Preferred embodiments of the bonding material of the present disclosure are the same as those of the composition of the present disclosure described above.

<Sintered body>
The sintered body of the present disclosure is obtained by sintering the composition of the present disclosure. The method for sintering the composition of the present disclosure is not particularly limited.
The electric resistivity of the sintered body is preferably 1 × 10 ⁻⁴ Ω · cm or less.

<Joint body and its manufacturing method>
The joined body of the present disclosure is one in which the element and the support member are joined via the sintered body of the present disclosure.
The support member is not particularly limited, and a material in which the material of the portion where the elements are joined is metal is used. Examples of the metal as the material of the portion where the elements are joined include gold, silver, copper, nickel, and the like. Further, among the above, a plurality of metals may be patterned on the base material to form a support member.
Specific examples of the support member include a lead frame, a wired tape carrier, a rigid wiring board, a flexible wiring board, a wired glass substrate, a wired silicon wafer, and a wafer level CSP (Wafer Level Chip Size Package). Re-wiring layer.
The elements are not particularly limited, and include active elements such as semiconductor chips, transistors, diodes, light emitting diodes, and thyristors, and passive elements such as capacitors, resistors, resistor arrays, coils, and switches.
In addition, examples of the joined body of the present disclosure include a semiconductor device and an electronic component. Specific examples of the semiconductor device include a diode, a rectifier, a thyristor, a metal oxide semiconductor (MOS) gate driver, a power switch, a power oxide semiconductor field-effect transistor (IGBT), and an IGBT (insulator transistor). Examples include a power module including a fast recovery diode, a transmitter, an amplifier, and an LED module.

The method for manufacturing a joined body according to the present disclosure includes forming a composition layer by applying the composition of the present disclosure to at least one of a portion of the support member where the device is joined and a portion of the device where the device is joined to the support member. Performing, contacting the support member with the element via the composition layer, and heating and sintering the composition layer.
The step of applying the composition to form the composition layer may include the step of drying the applied composition.

A composition layer is formed by applying the composition of the present disclosure to at least one of a portion of the support member where the element is bonded and a portion of the device where the device is bonded to the support member.
Examples of the method for applying the composition include a coating method and a printing method.
As a coating method for applying the composition, for example, dipping, spray coating, bar coating, die coating, comma coating, slit coating, and application using an applicator can be used. As a printing method for printing the composition, for example, a dispenser method, a stencil printing method, an intaglio printing method, a screen printing method, a needle dispenser method, and a jet dispenser method can be used.

The composition layer formed by applying the composition is preferably dried from the viewpoint of suppressing the flow of the composition and the generation of voids during heating.
As a method for drying the composition layer, drying by standing at room temperature (for example, 25 ° C.), drying by heating, or drying under reduced pressure can be used. For heating drying or vacuum drying, hot plate, hot air dryer, hot air heating furnace, nitrogen dryer, infrared dryer, infrared heating furnace, far infrared heating furnace, microwave heating device, laser heating device, electromagnetic heating device , A heater heating device, a steam heating furnace, a hot plate pressing device, or the like.
The temperature and time for drying can be appropriately adjusted according to the type and amount of the solvent used. For example, drying at 50 ° C. to 180 ° C. for 1 minute to 120 minutes is preferable.
After the formation of the composition layer, the element and the supporting member are brought into contact with each other, whereby the element and the supporting member are bonded to each other with the composition layer interposed therebetween. The step of drying the applied composition may be performed before or after the step of bringing the support member into contact with the element.

Next, a sintered body is formed by heating the composition layer. The sintering of the composition layer may be performed by a heat treatment or a heat and pressure treatment.
For heating treatment, hot plate, hot air dryer, hot air heating furnace, nitrogen dryer, infrared dryer, infrared heating furnace, far infrared heating furnace, microwave heating device, laser heating device, electromagnetic heating device, heater heating An apparatus, a steam heating furnace, or the like can be used.
For the heating and pressing treatment, a hot plate press device or the like may be used, or the above-described heating treatment may be performed while applying pressure.
The heating temperature in the sintering of the composition layer can be selected according to the type and content of the components contained in the composition. For example, the melting point is preferably equal to or higher than the melting point of the metal particles B. Specifically, the temperature is preferably 180 ° C. or higher, more preferably 190 ° C. or higher, and further preferably 220 ° C. or higher. The upper limit of the heating temperature is not particularly limited, but may be, for example, 300 ° C. or lower.
The heating time in the sintering of the composition layer can be selected according to the type and content of the components contained in the composition. For example, the duration is preferably from 5 seconds to 10 hours, more preferably from 1 minute to 30 minutes, even more preferably from 3 minutes to 10 minutes.
In the method for manufacturing a joined body according to the present disclosure, the sintering of the composition layer is preferably performed in an atmosphere having a low oxygen concentration. The low oxygen concentration atmosphere refers to a state in which the oxygen concentration is 1000 ppm or less, and preferably 500 ppm or less.

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

(Preparation of composition)
Each component shown in Table 1 was mixed in an amount (unit: g) shown in Table 1 to prepare a composition. Details of the components shown in Table 1 are as follows.
Metal component 1: Cu particles having an average particle size of 3 μm Metal component 2: Cu particles having an average particle size of 5 μm Metal component 3: Cu particles having an average particle size of 25 μm Metal component 4: SAC particles having an average particle size of 3 μm (Sn96.5% by mass) , Ag 3.0% by mass, Cu 0.5% by mass, density: 4.00 g / cm ³ )
Metal component 5: SAC particles having an average particle size of 25 μm (Sn96.5% by mass, Ag 3.0% by mass, Cu 0.5% by mass, density: 5.88 g / cm ³ )
Metal component 6: SnBi alloy particles having an average particle diameter of 7 μm (Sn 42% by mass, Bi 58% by mass, density: 5.56 g / cm ³ )

As the organic components, 0.69% by mass of an epoxy resin (bisphenol A type epoxy resin), 1.44% by mass of rosin (dehydroabietic acid), 0.36% by mass of a thixotropic agent (12-hydroxystearic acid), and an activator ( A mixture of 1.44% by mass of triethanolamine, 0.08% by mass of an antioxidant (“Irganox 1010” manufactured by BASF) and 2.00% by mass of a solvent (2- (2-hexyloxyethoxy) ethanol) was used.

(Calculation of Z / XY)
The void volume X (cm ³ ) of the metal particles A (Cu particles) is calculated, and the value XY (g) obtained by multiplying by the density (g / cm ³ ) of the metal particles B (SAC particles) is mixed with the metal particles B. The value of Z / XY was determined by dividing by the amount Z (g).

(Die shear strength)
The prepared composition was applied to a copper lead frame using sharp tweezers to form a composition layer. An Si chip having a size of 2 mm × 2 mm and a gold-plated surface was placed on the composition layer, and lightly pressed with tweezers to obtain a sample of the composition before sintering. After the sample before sintering was dried on a hot plate at 100 ° C. for 30 minutes, it was set on a conveyor of a nitrogen reflow apparatus (Tamura Seisakusho Co., Ltd .: 1 zone 50 cm, 7 zone configuration, under a nitrogen stream), and the oxygen concentration was 200 ppm. It was conveyed at a speed of 0.3 m / min below. At this time, the sample was heated at 250 ° C. or more for 1 minute or more to obtain a sintered sample of the composition. Next, using a universal bond tester (4000 series, manufactured by DAGE) equipped with a 1 kN load cell, the Si chip was pressed horizontally at a measurement speed of 500 μm / s and a measurement height of 100 μm, and the die-share of a sintered sample of the composition was performed. The strength was measured. The average of the results of the nine measurements was taken as the die shear strength. If the die shear strength is less than 20 MPa, it can be said that the adhesion is poor.

(Thermal conductivity)
A sintered product of the composition prepared in the same manner as in the die shear strength measurement was polished with a polishing paper to a size of 12 mm in diameter and 0.5 mm in thickness to prepare a test piece for measuring thermal conductivity. Then, using a Xe flash method thermal conductivity measurement device (Nano Flash, LFA447, manufactured by NETZCCH), the lamp voltage was 247.0 V, the pulse width was 0.06 mm, and the diffusion model was tested from the following equation A under the conditions of the Cowan model. The thermal conductivity λ (W / (m · K)) of the piece was measured.

λ = αρc Expression A
α: thermal diffusivity (m ² / s)
ρ: density (kg / m ³ )
c: Specific heat capacity (J / kg · K)

(Continuous printing time)
An applicator and 150 g of metal paste were applied on an aluminum plate on an Auto Film Applicator (manufactured by Tester Sangyo Co., Ltd.). The metal paste was repeatedly printed under the following conditions: speed: 10 mm / sec, film thickness (gap): 0.0 mm, number of times: 6 times / 1 hour, and the fluidity was visually observed. In addition, 15 g of the metal paste was collected every hour, and the volatilization ratio and viscosity of the solvent were confirmed. Table 1 shows the time from the start of the test until the viscosity becomes 250 Pa · s or more.

(Reliability test)
A sintered sample of the composition was prepared in the same manner as in the measurement of the die shear strength. A sintered sample of the composition was set in a thermal shock tester (Type 6015, manufactured by Life Tech Co., Ltd.), and a cooling / heating cycle test in which cooling and heating were repeated was performed. Specifically, first, cool at room temperature (25 ° C.) at a rate of −10 ° C./min and maintain at −65 ° C. for 30 minutes, then heat at a rate of + 10 ° C./min and maintain at 175 ° C. for 30 minutes. Thereafter, an operation of cooling to room temperature (25 ° C.) at a rate of −10 ° C. per minute was defined as one cycle.

(4) Cross-sectional SEM observation of the sample after 500 cycles, 1000 cycles, 2000 cycles, and 3000 cycles from the start of the cooling / heating cycle test was performed to check whether cracks were generated. In Table 1, “> 3000” means that no cracks occurred even after 3000 cycles, and “> 2000” means that no cracks occurred after 2000 cycles but cracks occurred after 3000 cycles. , "> 1000" means that no crack occurred after 1000 cycles, but crack occurred after 2000 cycles.

(Surface sinterability)
The surface of the sintered product obtained by the evaluation of the die shear strength was visually observed and evaluated according to the following evaluation criteria.
A: The color of the surface of the sintered product changed from reddish brown derived from Cu to gray derived from a metal compound composed of Cu and Su.
B: The color of the surface of the sintered product remained reddish brown derived from Cu.

As shown in Table 1, a sintered product prepared using the composition of the example in which the value of Z / XY is in the range of 0.8 to 1.2 has a large die shear strength, excellent bonding strength, and It also had excellent thermal conductivity.

All documents, patent applications, and technical standards mentioned herein are to the same extent as if each individual document, patent application, and technical standard were specifically and individually stated to be incorporated by reference. Incorporated herein by reference.

Claims

It contains a metal component capable of transitional liquid phase sintering, and the metal component includes metal particles A having a melting point higher than 300 ° C. and metal particles B having a melting point of 300 ° C. or less. (Cm 3 ), a composition in which the density Y (g / cm 3 ) of the metal particles B and the amount Z (g) of the metal particles B satisfy the following formula.
0.8 ≦ Z / XY ≦ 1.2
The composition according to claim 1, wherein the void volume X of the metal particles A is 50% by volume or less of the apparent volume of the metal particles A.
The composition according to claim 1 or 2, wherein the metal particles A contain Cu.
(4) The composition according to any one of (1) to (3), wherein the metal particles B contain Sn.
[4] A bonding material containing the composition according to any one of [1] to [4].
焼結 A sintered body of the composition according to any one of claims 1 to 5.
A joined body in which the element and the support member are joined via the sintered body according to claim 5.
The composition layer according to any one of claims 1 to 4, wherein the composition according to any one of claims 1 to 4 is applied to at least one of a position where the element is joined to the support member and a position where the device is joined to the support member. Forming a;
Contacting the support member and the element through the composition layer,
Heating the composition layer and sintering the composition layer.