JP2003142620A - Electronic apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem wherein, when a heat history of 230 to 240 deg.C is applied, if the electronic apparatus is mounted in an external electric circuit or the like, a sealing material itself for connecting the insulating base of the apparatus to the cover is melted so that a sealability in the apparatus cannot be assured. SOLUTION: In the electronic apparatus 1, the insulating base 3 having a frame-like metallized metal layer 2a on an upper surface is connected to the cover 3 having a frame-like metallized metal layer 3a on a lower surface, by a sealing material 4 containing a filler 4b having a higher melting point than that of a solder 4a in a solder 4 containing a tin as a main component. Consequently, an electronic component 6 is hermetically contained in a space 5 formed of the base 2 and the cover 3. In this apparatus 1, the filler 4b has an alloy layer 4c having a solid phase line temperature of 250 deg.C or higher formed by reacting with the solder 4a on the surface of the filler 4b, and the alloy layers 4c of the adjacent filler 4b are connected to each other.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic device in which electronic parts such as a semiconductor element and a piezoelectric vibrator are hermetically housed, and more particularly to an electronic device hermetically sealed by using lead-free solder.

[0002]

2. Description of the Related Art Conventionally, an electronic component housing container for housing electronic components such as semiconductor elements is made of an electrically insulating material such as an aluminum oxide sintered body, and the electronic components are provided in the substantially central portion of its upper surface. An insulating substrate having a plurality of metallized wiring layers made of a refractory metal such as tungsten and molybdenum led out from the recess for accommodating and its periphery to the outside, and a sealing material adhered to the outer peripheral portion of the upper surface. , Which is also made of an electrically insulating material, is connected to the metallized wiring layer, which is connected to the metallized wiring layer and the lid body having the outer peripheral portion of the lower surface electrically connected to the external electric circuit. And an external lead terminal made of a metal material such as an iron-nickel alloy or an iron-nickel-cobalt alloy. Then, the external lead terminals are connected and fixed to the metallized wiring layer of the insulating substrate through a brazing material such as silver solder, and then electronic components such as semiconductor elements are attached to the bottom surface of the recess of the insulating substrate through an adhesive. At the same time, each electrode of the electronic component is connected to the metallized wiring layer via a bonding wire, and thereafter, the insulating substrate and the lid are adhered to the opposite main surfaces thereof, and the respective sealing materials are melted and integrated. Then, the container made up of the insulating substrate and the lid is sealed to form an electronic device as a final product. In such a conventional electronic device, solder containing lead as a main component has been used as a sealing material for joining the insulating base and the lid.

However, when lead contained in the encapsulant is designated as an environmental pollutant and, for example, an electronic device using a solder containing lead is discarded or left outdoors and exposed to the wind and rain, it is exposed to the environment. There is a risk that lead will melt out and pollute the environment, and in recent years, a lead-free encapsulant has been required due to the increasing global environmental protection movement.

Therefore, various encapsulating materials which do not use lead, which is harmful to the human body, have been developed and proposed. As such a sealing material, for example, various solders containing tin, bismuth-silver, zinc-aluminum or the like as a main component are adopted.

[0005]

[Problems to be Solved by the Invention] However, tin and silver
Solder made of an alloy containing zinc has a temperature of -55 to +12.
Although it shows excellent reliability in heat fatigue resistance under the temperature cycle condition of 5 ° C, the melting points of the solders containing them are all 225 ° C or less, and this solder is used as an insulating substrate and a lid. When used as a hermetically sealing material, 230 to 240 when mounting an electronic device on an external electrical circuit etc.
There is a problem that the sealing material is remelted due to the heat history of ℃ and the airtight sealing inside the electronic device is broken.

Further, the solder containing bismuth-silver as a main component is inferior in heat fatigue resistance under a temperature cycle condition of -55 to + 125 ° C. and lacks airtight reliability, so that it is used for hermetic sealing of electronic devices. Had the problem of being inappropriate.

Further, the solder containing zinc-aluminum as a main component easily corrodes when left in the air, and lacks long-term airtight reliability, so that it is necessary to use it for airtight sealing of electronic devices. Was also inappropriate.

The present invention has been completed in view of the above conventional problems, and an object thereof is to mount an electronic device on an external electric circuit or the like even if a thermal history of 230 to 240 ° C. is applied. It is an object of the present invention to provide an electronic device which can secure the airtightness of the material, is excellent in the corrosion resistance of the sealing material itself, and is environmentally friendly without containing lead.

[0009]

In the electronic device of the present invention, an insulating substrate having a frame-shaped metallized metal layer on its upper surface and a lid having a frame-shaped metallized metal layer on its lower surface are mainly made of tin. In an electronic device in which an electronic component is hermetically housed inside a space formed by the insulating base and the lid by joining a solder as a component with a sealing material containing a filler having a melting point higher than that of the solder The filler is formed on the surface of the filler with an alloy layer having a solidus temperature of 250 ° C. or higher formed by reacting with the solder, and the alloy layers of adjacent fillers are bonded to each other. It is characterized by being present.

Further, the electronic device of the present invention is characterized in that, in the above structure, the alloy layer has a thickness of 0.5 to 10 μm.

Further, the electronic device of the present invention is characterized in that, in the above-mentioned constitution, the filler is silver particles having an average particle diameter of 5 to 40 μm.

The electronic device of the present invention is characterized in that, in the above structure, the sealing material contains 5 to 25% by weight of the filler.

According to the electronic device of the present invention, 250 is formed on the surface of the filler contained in the sealing material by reacting with the solder.
Since the alloy layer having a solidus temperature of ℃ or more is formed and the adjacent alloy layers of the filler are joined together, the alloy layer forms a three-dimensional and continuous skeleton in the encapsulating material. Does not melt at temperatures lower than 250 ° C, and as a result, the encapsulant will melt even if a thermal history of 230 to 240 ° C is applied to the electronic device when it is mounted on an external electric circuit or the like. It is possible to provide an electronic device that is highly airtight and reliable without breaking the airtight seal inside the electronic device.

Further, according to the electronic device of the present invention, in the above structure, the thickness of the alloy layer formed on the surface of the filler is
Since the thickness is 0.5 to 10 μm, the sealing material can have excellent fluidity and heat resistance, and as a result, an electronic device having better airtight sealing and heat resistance can be obtained. You can

Further, according to the electronic device of the present invention, in the above structure, since the filler is silver particles having an average particle size of 5 to 40 μm, silver easily reacts with tin which is a main component of solder. , Forming a eutectic alloy layer with a solid layer line temperature of 250 ℃ or more on the filler surface and adjoining adjacent alloy layers satisfactorily, resulting in excellent heat resistance and highly reliable hermetic sealing It can be a device.

Further, according to the electronic device of the present invention, in the above structure, since the sealing material contains 5 to 25% by weight of the filler, an alloy having a solidus temperature of 250 ° C. or more on the surface of the filler. The layers can be formed at an appropriate ratio, and the alloy layers of the filler can be satisfactorily joined to each other. As a result, an electronic device having excellent heat resistance and airtight sealing can be obtained.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION Next, an electronic device of the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is a sectional view showing an example of an embodiment of an electronic device of the present invention. In the figure, reference numeral 1 denotes an electronic device. The electronic device 1 has a lid body having an insulating substrate 2 mainly having a frame-shaped metallized metal layer 2a deposited on the upper surface and a frame-shaped metallized metal layer 3a on the lower surface. 3, the sealing material 4, the electronic component 6, and the metallized wiring layer 7
It consists of and.

The insulating base 2 is provided with a cavity 5 for accommodating the electronic component 6 in the center of its upper surface, and the electronic component 6 is made of glass, resin, brazing material or the like on the bottom surface of the cavity 5. It is adhesively fixed through an adhesive.

Further, the insulating substrate 2 has a plurality of metallized wiring layers 7 deposited from the bottom surface of the void 5 to the outer peripheral portion thereof. The metallized wiring layer 7 is located at the portion located on the bottom surface of the void 5. Each electrode of the electronic component 6 is electrically connected through the bonding wire 8, and an external lead terminal 9 connected to an external electric circuit (not shown) is connected to an external electric circuit (not shown) through a brazing material 10 at a portion to be led to the outside. It is attached.

Further, on the outer peripheral portion of the upper surface of the insulating base 2,
A frame-shaped metallized metal layer 2 for joining with a lid 3 described later.
The insulating substrate 2 to which a is adhered is made of an electrically insulating material such as a sintered body containing aluminum oxide, mullite, aluminum nitride, silicon carbide, glass ceramics, etc. as a main component, and, for example, an aluminum oxide sintered body. When it is composed of alumina, firstly alumina (Al ₂ O ₃ ) or silica (SiO ₂ )
・ Calcia (CaO), magnesia (MgO) and other raw material powders are mixed with an appropriate organic solvent / solvent to form a slurry, which is then formed using the well-known doctor blade method or calender roll method. Shape to obtain a ceramic green sheet, after which the ceramic green sheet is punched into a predetermined shape and a plurality of layers are laminated,
It is manufactured by firing at a temperature of about 1600 ° C.

The metallized wiring layer 7 and the frame-shaped metallized metal layer 2a are made of a refractory metal such as tungsten, molybdenum and manganese, and a metal paste prepared by adding and mixing an organic solvent and a solvent to these powders is used as ceramic green. It is formed by depositing a predetermined pattern on a predetermined position of the sheet by a conventionally known screen printing method and firing the ceramic green sheet at the same time. It should be noted that the metallized wiring layer 7 and the frame-shaped metallized metal layer 2a are coated with a metal such as nickel or gold, which has excellent corrosion resistance and has good wettability with a brazing material such as solder, by a plating method or the like. When the metallized wiring layer 7 and the frame-shaped metallized metal layer 2a are deposited so as to have a thickness of 20 μm, oxidative corrosion can be effectively prevented.

On the other hand, the lid 3 is made of, for example, alumina (Al ₂
O ₃ ), silica (SiO ₂ ), calcia (CaO), magnesia (MgO) and other raw material powders are filled in a predetermined press die and pressed at a constant pressure to form a compact.
It is manufactured by firing at a temperature of ℃.

A frame-shaped metallized metal layer 3a for joining with the insulating substrate 2 is formed on the outer peripheral portion of the lower surface of the lid 3. The frame-shaped metallized metal layer 3a is made of a refractory metal such as tungsten or molybdenum / manganese, like the frame-shaped metallized metal layer 2a described above, and a metal paste prepared by adding and mixing an organic solvent / solvent to these powders. Is formed on a predetermined position of the lid body 3 by a well-known screen printing method in a predetermined pattern and then baked. The frame-shaped metallized metal layer 3a has a surface on which a metal such as nickel or gold having excellent corrosion resistance and having good wettability with a brazing material such as solder is plated by a plating method or the like.
By depositing it to a thickness of 1.0 to 20 μm, it is possible to effectively prevent oxidative corrosion of the frame-shaped metallized metal layer 3a.

Then, the electronic component 6 is adhered and fixed to the bottom surface of the void 5 of the insulating substrate 2 through an adhesive such as glass, resin or brazing material, and each electrode of the electronic component 6 and the metallized wiring layer 7 are bonded. After electrically connecting via the wire 8, the frame-shaped metallized metal layers 2a and 3a adhered to the insulating substrate 2 and the lid 3 respectively are attached to the solder 4a containing tin as a main component. The electronic device 1 is completed by joining with the sealing material 4 containing the filler 4b having a higher melting point.

In the electronic device 1 of the present invention, as shown in the enlarged cross-sectional view of the main part of the electronic device 1 in FIG. 2, the sealing material 4 is a solder 4a containing tin as a main component, a filler 4b, and a filler 4b. It is composed of an alloy layer 4c formed on the surface.
This is also important.

As the solder 4a containing tin as a main component, for example, a eutectic composed of tin 96.5% by weight and silver 3.5% by weight, tin 9
Eutectic composed of 5.75 wt%, silver 3.5 wt% and copper 0.75 wt%, eutectic composed of tin 92 wt% and zinc 8 wt%, tin 99.3
A eutectic or the like consisting of 1% by weight and 0.7% by weight of copper, or various lead-free solders having a composition close to those of the eutectic are used.

Such a solder 4a can be melted at a temperature as low as possible because it is necessary to hold a filler 4b which will be described later in the sealing material 4, and from the viewpoint of thermal protection and residual stress of the electronic component 6. Those having a melting temperature which is basically lower than the melting point of the filler 4b are preferable. By setting the melting temperature of the solder 4a to be equal to or lower than the melting point of the filler 4b, when the solder 4a is melted, a solidus temperature higher than the melting point of the solder 4a is generated on the surface of the filler 4b having a higher melting point. It becomes possible to form the alloy layer 4c which it has. A eutectic consisting of 96.5% by weight tin and 3.5% by weight silver has a melting temperature of approximately 221 ° C, contains silver with excellent thermal conductivity, and is three-dimensional and continuous with excellent heat resistance. The alloy layer 4c having the above-mentioned skeleton is formed, and the heat is effectively released to the heat history at the time of mounting, so that it is preferably used.

The amount of the solder 4a needs to be supplied so that the solder 4a can spread between the fillers 4b and fill the gap. In addition, the solder 4a and the filler 4
In order to improve the wettability with b and facilitate the uniform formation of the alloy layer 4c on the surface of the filler 4b, additives such as various flux components typified by pine resin are added to the sealing material 4 in the alloy layer. It is also effective to add 4c in a range that does not lower the solidus temperature and to heat the sealing material 4 in an inert gas atmosphere or a reducing gas atmosphere.

The filler 4b is the solder 4 containing tin as a main component.
250 ℃ with a melting point higher than that of a and a tin content of 50 wt% or less
Various fillers that form the alloy layer 4c having the above solidus temperature can be applied. Examples of the filler 4b include metal particles of silver, copper, aluminum, gold, iron, palladium, platinum, titanium, etc., alloy particles containing these metals, or ceramics or glass coated with these metals. Examples include inorganic particles. In particular, the silver particles have good wettability with the solder 4a containing tin as a main component, have little influence on the fluidity of the solder 4a, and further, silver forms an alloy with tin having a high solidus temperature. However, it is also preferably used because it has excellent thermal conductivity. In addition, you may use the metal particle containing silver and the particle which coat | covered the surface with silver.

The shape of the filler 4b is basically preferably spherical, but it does not necessarily have to be true spherical, and it may be elliptic spherical or cylindrical, and the filler 4 in the present invention.
Various different shapes may be used as long as they can function as b.

Further, the filler 4b preferably has an average particle size of 5 to 40 μm from the viewpoint of fluidity of the sealing material 4 when hermetically sealing. By setting the average particle size of the filler 4b to 5 to 40 μm, the surface of the filler 4b easily reacts with the solder 4a containing tin as a main component in the sealing material 4 to form an alloy layer 4c with tin. , The adjacent alloy layers 4c are joined to each other to have excellent heat resistance, and the strong alloy layer 4b is formed as a three-dimensional and continuous skeleton, so that the heat resistance of the sealing material 4 is improved and the heat conductivity is also excellent. Can be one.

If the average particle size of the filler 4b is less than 5 μm, there is a risk that the filler 4b will melt and disappear when the sealing material 4 is melted.
If it exceeds, it tends to be difficult to form a three-dimensional and continuous frame densely. Therefore, the average particle size of the filler 4b is preferably 5 to 40 μm. The three-dimensional and continuous skeleton means that the alloy layer 4c formed on the surface of the core filler 4b is joined to the alloy layer 4c formed on the surfaces of the adjacent fillers 4b on the left, right, top, and bottom, This indicates that the entire sealing material 4 is in a three-dimensional and continuous bonded state, and the space formed by this skeleton is filled with solder 4a.

When the filler 4b is a metal material, the content of the filler 4b is 1 to 30 in consideration of the improvement of the heat resistance of the sealing material 4 and the wettability and fluidity of the solder 4a containing tin as a main component. Weight percent is preferred. Especially in the case of silver particles,
If it is wt%, the fluidity of the sealing material 4 at the time of hermetic sealing is good, and it reacts with the solder 4a containing tin as a main component in the sealing material 4 and has excellent heat resistance on the surface of the silver particles. The alloy layer 4c having a large thickness can be easily formed.

Further, the same effect can be obtained even if the filler 4b is formed by depositing a metal film on the inorganic material particles, and in particular, from the viewpoint of thermal conductivity, the inorganic material particles are 58.6%.
Aluminum nitride or 268W with a thermal conductivity of W / mK
Silicon carbide or the like having a thermal conductivity of / mK is suitable. Furthermore, from the viewpoint of the wettability and the fluidity of the solder 4a, the average particle size of the inorganic material particles coated with the metal film is not problematic as long as it is the same as the above metal material. Therefore, the content of the inorganic material may be equivalent to that of the metal material, while having the same effect as that of the metal material.

Therefore, when silver particles are used as the filler 4b, the particle size thereof is determined by the sealing material 4 used for hermetic sealing.
And the solder 4a containing tin as a main component in the encapsulating material 4 easily react with each other to form a eutectic alloy with tin, and the eutectic alloys are bonded to each other to have excellent heat resistance. From the viewpoint that it is easy to form a strong three-dimensional and continuous frame,
40 μm is preferable. Moreover, the content is 5 to 25% by weight.
Is preferable for the following reasons. That is, when the content is within the above range, the flowability of the sealing material 4 is good and the alloy layer 4 having a thickness excellent in heat resistance is formed on the surface of the silver particles.
c, and when the electronic device 1 is mounted on an external electric circuit, even if the solder 4a is melted, the solidly bonded alloy layer 4c forming a three-dimensional and continuous frame having excellent heat resistance forms the solder 4a. The airtight seal of the container is maintained and not broken.

Further, the alloy layer 4c in the present invention needs to have a solidus temperature exceeding the heating temperature of 230 to 240 ° C. when mounting the electronic device 1 on an external electric circuit or the like.
Thereby, even when the sealing material 4 is exposed to the heating temperature at the time of mounting, the alloy layer 4c forms a three-dimensional and continuous skeleton in the sealing material 4, and the sealing material 4 has a temperature lower than 250 ° C. As a result, even if the electronic device is subjected to a heat history of 230 to 240 ° C. when it is mounted on an external electric circuit or the like, the sealing material 4 is melted and the air inside the electronic device is melted. It is possible to provide an electronic device that is highly airtight and highly reliable without breaking the tight seal.

The thickness of the alloy layer 4c is preferably 0.1 μm or more from the viewpoint of improving heat resistance and holding strength of the solder 4a in the alloy layer 4c having a three-dimensional and continuous frame structure.
Further, considering the fluidity of the sealing material 4, the thickness of the alloy layer 4c is preferably 30 μm or less. In particular, the alloy layer 4c has a thickness of 10
When the thickness is less than or equal to μm, the fluidity of the sealing material 4 is good, and from the viewpoint that the heat resistance of the alloy layer 4c is stably improved, 0.5 μm or more is preferable. Therefore, the thickness of the sealing material 4 is 0.5 to 10 μm because the sealing material 4 has the fluidity of the sealing material 4 and the alloy layer 4c excellent in heat resistance.
Is the best.

In order to bond the insulating substrate 2 and the lid 3 with the sealing material 4 as described above, first, a screen is formed on the surface of the frame-shaped metallized metal layer 3a covering the lid 3 with the sealing material 4. Printing and application are performed by using a printing method, and then the lid is so placed that the sealing material 4 is sandwiched between the frame-shaped metallized metal layer 2a of the insulating substrate 2 and the frame-shaped metallized metal layer 3a of the lid 3. The body 3 is placed on the insulating base 2, and then the lid 3 is placed on the insulating base 2.
The sealing material 4 is melted by heating it to a temperature of about 300 to 350 ° C. while pressing it to the side with a constant pressure, whereby an alloy with tin is formed on the surface of the filler 4 b and a three-dimensional and continuous alloy layer 4 c is formed. Is formed, and the lid 3 is airtightly joined to the upper surface of the insulating base 2.

Next, an example of a method of manufacturing the electronic device of the present invention will be described. First, a semiconductor element, which is a type of electronic component 6, is bonded and fixed to the bottom surface of the space 5 at the center of the upper surface of the insulating substrate 2 made of an alumina-based sintered body through an adhesive such as glass, resin, or a brazing material. Each electrode of the electronic component 6 is electrically connected to the metallized wiring layer 7 via the bonding wire 8. After that, frame-shaped metallized metal layers 2a and 3a are formed on the upper surface of the insulating substrate 2 and the lower surface of the lid 3 in advance. Next, 20% by weight of spherical silver powder having an average particle diameter of 30 μm is applied to the solder 4a composed of 96.5% by weight of tin and 3.5% by weight of silver on the surface of the frame-shaped metallized metal layer 3a of the lid body 3.
The dispersed sealing material 4 is applied. Furthermore, this lid 3
While being pressed against the frame-shaped metallized metal layer 2a on the upper surface of the insulating substrate 2, heat bonding is performed at a temperature of 330 ° C. By this heat bonding, a silver-tin alloy having a rich silver and a solidus temperature of 480 ° C. or higher is formed on the surface of the silver powder, and adjacent silver-tin alloys are bonded to each other and have an average thickness of 8 μm. A three-dimensional and continuous alloy layer 4c is formed.

Thus, the electronic device 1 as a product in which the electronic component 6 is hermetically sealed inside the void 5 is obtained. After mounting the electronic device 1 on an external electric circuit at a temperature of 240 ° C., an airtightness evaluation test of the electronic device 1 was performed to confirm that the airtightness was maintained.

The present invention is not limited to the above embodiments, and various modifications can be made without departing from the scope of the present invention. In the above embodiments, a semiconductor element is used as an electronic component. Although the electronic device housing this is described in detail above, it is also applicable to an electronic device housing electronic components such as a piezoelectric vibrator and a surface acoustic wave element. Further, although the lid is made of an insulating material in the above-mentioned embodiments, it may be made of a metal material such as an iron-nickel alloy or an iron-nickel-cobalt alloy.

[0042]

According to the electronic device of the present invention, it is formed on the surface of the filler contained in the sealing material by reacting with the solder.
Forming an alloy layer having a solidus temperature of 0 ° C or more and joining adjacent alloy layers of the filler to form a three-dimensional and continuous skeleton of the alloy layer in the encapsulant, and sealing The material does not melt at temperatures below 250 ° C, and as a result, the encapsulant melts even if a thermal history of 230 to 240 ° C is applied to the electronic device when mounting it on an external electric circuit. As a result, it is possible to obtain an electronic device that is highly airtight and highly reliable without breaking the airtight seal inside the electronic device.

Further, according to the electronic device of the present invention, in the above structure, the thickness of the alloy layer formed on the surface of the filler is
Since the thickness is 0.5 to 10 μm, the sealing material can have excellent fluidity and heat resistance, and as a result, an electronic device having better airtight sealing and heat resistance can be obtained. You can

Further, according to the electronic device of the present invention, in the above structure, since the filler is silver particles having an average particle size of 5 to 40 μm, silver easily reacts with tin which is a main component of solder. , Forming a eutectic alloy layer with a solid layer line temperature of 250 ℃ or more on the filler surface and adjoining adjacent alloy layers satisfactorily, resulting in excellent heat resistance and highly reliable hermetic sealing It can be a device.

Further, according to the electronic device of the present invention, in the above structure, since the sealing material contains 5 to 25% by weight of the filler, an alloy having a solidus temperature of 250 ° C. or higher on the surface of the filler. The layers can be formed at an appropriate ratio, and the alloy layers of the filler can be satisfactorily joined to each other. As a result, an electronic device having excellent heat resistance and airtight sealing can be obtained.

[Brief description of drawings]

FIG. 1 is a sectional view showing an example of an embodiment of an electronic device of the present invention.

FIG. 2 is an enlarged cross-sectional view of an essential part of the electronic device of the present invention.

[Explanation of symbols]

1 ... Electronic device 2 ... Insulating substrate 2a --- Frame-shaped metallized metal layer 3 ... Lid 3a .... Frame-shaped metallized metal layer 4 ... Encapsulating material 4a ... Solder containing tin as a main component 4b ... Filler 4c ··· Alloy layer 5 ... Vacancy 6 ... Electronic parts

Claims (4)

[Claims] 1. An insulating substrate having a frame-shaped metallized metal layer on its upper surface and a lid having a frame-shaped metallized metal layer on its lower surface are soldered to a solder containing tin as a main component and having a higher melting point than the solder. In an electronic device in which an electronic component is hermetically housed inside a space composed of the insulating base and the lid by joining with a sealing material containing a filler, the filler is the solder on the surface of the filler. Formed by reacting with
An electronic device, wherein an alloy layer having a solidus temperature of 50 ° C. or higher is formed, and the alloy layers of the adjacent fillers are bonded to each other. 2. The electronic device according to claim 1, wherein the alloy layer has a thickness of 0.5 to 10 μm. 3. The filler has an average particle size of 5 to 40 μm.
The electronic device according to claim 1 or 2, wherein the electronic device is a silver particle of m. 4. The sealing material contains 5 to 25 of the filler.
The electronic device according to any one of claims 1 to 3, wherein the electronic device contains wt%.