JP2000040760A - Electronic device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable an electronic element housed in a semiconductor device to operate normally and stably for a long term, preventing a metal lid from being separated from the metallized metal layer of an insulating base, even if heat is repeatedly applied to an electronic device. SOLUTION: An electronic device is manufactured in a manner, where an electronic component 3 is mounted on the upside mount 1a of an insulating base 1, a frame-like metallized metal layer 5 is deposited surrounding the mount 1a, and a metal lid 2 is bonded to the frame-like metallic metal layer 5 through the intermediary of a brazing material 6 through electron beam welding. In this case, electron beam welding is carried out at a position within a distance of 50 μm or above from the outer periphery of the metal lid 2, and the outer periphery of the metal lid 2 is bent upward. A large pool of brazing material 6 is provided between the outer periphery of the metal lid 2 and the metallized metal layer 5 and the joint between them in bonding strength can be increased, so that the electronic component 3 housed inside can operate normally and stably over a long term.

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 components such as a piezoelectric vibrator and a semiconductor element are hermetically accommodated in a container formed of an insulating base such as ceramics and a metal lid.

[0002]

2. Description of the Related Art Electronic components such as a piezoelectric vibrator and a semiconductor element are hermetically housed in a container including an insulating base and a lid for accommodating the electronic components, thereby forming an electronic device as a product. .

The most reliable one of such electronic devices is made of ceramics such as an aluminum oxide sintered body, and has a mounting portion on which electronic components are mounted in the center of the upper surface and a mounting portion on the outer peripheral portion of the upper surface. A type in which an electronic component is hermetically sealed inside a container including a metal frame attached as described above and a metal lid joined to the metal frame of the metal frame by seam welding. belongs to. In this type of electronic device, after mounting an electronic component on a mounting portion of an insulating base, a metal lid is mounted on a metal frame attached to the insulating base, and a seam is formed on an outer peripheral edge of the metal lid. It is manufactured by rolling while a pair of roller electrodes of a welding machine are in contact with each other, applying a large current for welding between the roller electrodes, and seam-welding a metal lid to a metal frame.

In this type of electronic device, a metal frame is usually provided with a frame-shaped metallized metal layer on the upper surface of an insulating substrate so as to surround a mounting portion, and a nickel plating layer is formed on the metallized metal layer. After the deposition, the nickel plating layer is attached to the insulating base by brazing a metal frame to the deposited metallized metal layer via a brazing material such as silver brazing.

However, this type of electronic device is
When the metal lid is seam-welded to the metal frame attached to the insulating base after mounting the electronic component on the mounting portion of the insulating base, the moving speed of the roller electrode of the seam welding apparatus is at most 3
mm / sec, which is disadvantageous in that productivity is low because it takes a long time of several seconds to seam weld a metal cover of 3 mm square to a metal frame, for example.

Further, a metal frame is required as a base metal for seam welding a metal lid to an insulating base, and the height of the electronic device is increased by the amount of the metal frame. However, it also has the disadvantage that it becomes expensive.

In view of the above, a mounting portion for mounting electronic components is provided at a central portion of the upper surface, and a frame-shaped portion surrounding the mounting portion is provided at an outer peripheral portion of the upper surface.
A container comprising a ceramic insulating base having a metalized metal layer of about 10 to 20 μm and a metal lid is prepared, and electronic components are mounted on the mounting portion of the insulating base. There has been proposed an electronic device in which an electronic component is hermetically sealed inside a container including an insulating base and a metal lid by joining the lid made by electron beam welding with a brazing material therebetween. .

In this electronic device, the metal cover and the insulating base are joined by applying nickel plating to the metallized metal layer of the insulating base to a thickness of 2 to 5 μm and forming the metallized metallized metal with the nickel plating applied. A metal lid is placed on the metal layer with a brazing material interposed therebetween, and thereafter, the electron beam is irradiated on the upper surface of the metal lid while moving the electron beam along the frame-shaped metallized metal layer by a magnetic field, This is performed by melting the brazing material corresponding to the portion irradiated with the electron beam by the thermal energy of the irradiated electron beam.

According to this electronic device, since the electron beam is irradiated while being moved by the magnetic field, the electron beam is emitted.
It can be moved at a high speed of 300 mm / sec or more. For example, a metal cover of 3 mm square can be welded to the metallized metal layer of the insulating base in a very short time of 0.1 second or less. Extremely excellent. Furthermore, since a metal frame is not required as a base metal for welding,
Accordingly, the height of the electronic device can be reduced, and the cost is low.

[0010]

However, recently,
The size of electronic devices has been rapidly reduced, and the width of a frame-shaped metallized metal layer attached to the outer peripheral portion of the upper surface of the insulating base has been reduced to 0.
It has become as narrow as about 4 mm, and the joining area of the metallized metal layer and the metal lid by electron beam welding via a brazing material has become narrower. The strength has become weak. When heat or the like generated when an electronic component operates is repeatedly applied to the electronic device, thermal stress generated between the insulating base and the metal lid due to a difference in thermal expansion coefficient between the two. As a result, the metal lid is peeled off from the metallized metal layer, the airtightness of the container is broken, and the electronic components housed therein cannot be operated normally and stably for a long period of time. Was.

The present invention has been devised in view of the above problems, and has as its object to firmly join a metal cover to a metallized metal layer of an insulating substrate by electron beam welding with a brazing material interposed therebetween. As a result, even if heat is repeatedly applied to the electronic device, the metal lid does not peel off from the metallized metal layer of the insulating base, and the electronic components housed therein can operate normally and stably for a long period of time. It is to provide a simple electronic device.

[0012]

According to an electronic device of the present invention, an electronic component is mounted on a mounting portion on an upper surface of an insulating base, and a frame-shaped metallized metal layer is attached so as to surround the mounting portion. An electronic device in which a metal lid is joined by electron beam welding via a brazing material,
The electron beam welding is performed at a position 50 μm or more inside from the outer periphery of the metal lid, and the outer periphery of the metal lid is bent upward.

According to the electronic device of the present invention, the electron beam welding is performed at an inner position at least 50 μm away from the outer periphery of the metal lid, and the outer periphery of the metal lid is bent upward. As a result, a large brazing material pool is formed between the outer peripheral portion bent above the metal lid and the metallized metal layer of the insulating base, and the pool of the brazing material causes the metalized metal layer of the metal lid to be formed on the metallized metal layer. The joining strength becomes strong.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an electronic component according to the present invention will be described with reference to the accompanying drawings. FIG. 1 is a cross-sectional view showing an example of an embodiment of an electronic device according to the present invention.

The insulating substrate 1 is made of a ceramic such as an aluminum oxide sintered body or an aluminum nitride sintered body, and has a concave portion A for accommodating the electronic component 3 at the center of the upper surface thereof. The bottom of the recess A is the electronic component 3
The mounting portion 1a for mounting the
The electronic component 3 is mounted on a.

When the insulating substrate 1 is made of, for example, an aluminum oxide sintered body, a suitable organic binder or a solvent is added to a raw material powder of aluminum oxide, silicon oxide, magnesium oxide, calcium oxide or the like, and the mixture is mixed. The ceramic green sheet is formed by adopting a doctor blade method or a calender roll method, which is well known in the art, and thereafter, a plurality of ceramic green sheets are subjected to appropriate punching and laminated at a high temperature. It is manufactured by firing.

The insulating base 1 has a tungsten lead extending from the upper surface of the mounting portion 1a to the lower surface of the insulating base 1.
A metallized wiring layer 4 made of a metal powder sintered body of molybdenum or the like is adhered and formed.

The metallized wiring layer 4 functions as a conductive path for electrically leading each electrode of the electronic component 3 to the outside, and the electrode of the electronic component 3 is electrically connected to a portion of the upper surface of the mounting portion 1a. It is electrically connected via the agent.
On the other hand, a portion of the metallized wiring layer 4 extending to the lower surface of the insulating base 1 is electrically connected to a wiring conductor of an external electric circuit board (not shown) via, for example, solder.

If the metallized wiring layer 4 is made of, for example, a tungsten powder sintered body, a tungsten paste obtained by adding and mixing an appropriate organic binder and a solvent to the tungsten powder is applied to a ceramic green sheet serving as the insulating substrate 1. By printing and applying a predetermined pattern by a conventionally known screen printing method and firing this together with a ceramic green sheet serving as the insulating substrate 1, the insulating substrate 1 is adhered and derived in a predetermined pattern from the upper surface to the lower surface of the mounting portion 1a.

The metallized wiring layer 4 is coated with a metal having excellent corrosion resistance such as nickel and gold and excellent wettability with solder to a thickness of 1.0 to 20.0 μm by a plating method on the exposed surface. Thus, the oxidation corrosion of the metallized wiring layer 4 can be effectively prevented, and the connection between the metallized wiring layer 4 and the wiring conductor of the external electric circuit board can be strengthened. Therefore, the metallized wiring layer 4
On the surface of the metal, a metal with excellent corrosion resistance such as nickel and gold, and excellent wettability with solder is 1.0 to 20.0μ by plating method.
m.

A metallized metal layer 5 having a width of about 0.4 mm is formed on the outer peripheral portion of the upper surface of the insulating base 1 so as to surround the mounting portion 1a. The metal cover 2 is joined by an electron beam welding with a brazing material 6 interposed therebetween.

The metallized metal layer 5 functions as a base metal for joining the metal cover 2 to the insulating base 1 and is made of a sintered metal powder such as tungsten and molybdenum.
A metal paste obtained by adding and mixing an appropriate organic binder and a solvent to a metal powder such as tungsten is printed on a ceramic green sheet serving as the insulating substrate 1 in a predetermined thickness and a predetermined pattern in advance by using a conventionally known screen printing method. It is applied and fired together with a ceramic green sheet serving as the insulating substrate 1, thereby forming a frame on the upper surface of the insulating substrate 1 so as to surround the mounting portion 1 a.

The metallized metal layer 5 is coated with a metal having excellent corrosion resistance, such as nickel and gold, and excellent wettability with the brazing material 6 to a thickness of 1.0 to 20.0 μm by plating. In addition, the metallized metal layer 5 can be effectively prevented from being oxidized and corroded, and the metallized metal layer 5 and the metal lid 2 can be strongly welded to each other through the brazing material 6. Accordingly, the surface of the metallized metal layer 5 is coated with a metal such as nickel or gold having excellent corrosion resistance and excellent wettability with the brazing material 6 by plating.
It is preferable to apply it to a thickness of 20.0 μm.

The metal lid 2 joined by electron beam welding to the metallized metal layer 5 of the insulating base 1 via a brazing material 6 is made of, for example, an iron-nickel alloy plate or an iron-nickel-cobalt alloy. It is made of a plate, and is joined to the metallized metal layer 5 of the insulating base 1 by electron beam welding with a brazing material 6 interposed therebetween.
The electronic component 3 is hermetically sealed between the insulating base 1 and the inside of the concave portion A.

The joining between the metal lid 2 and the metallized metal layer 5 of the insulating substrate 1 by electron beam welding via the brazing material 6 is performed by connecting the flat metal lid 2 to the metallized metal layer of the insulating substrate 1. 5, a brazing material 6 is arranged and placed between them, and the metal cover 2 has a diameter of 0.1 to 0.2 on the upper surface thereof.
mm of the electron beam 7
The irradiation is performed while moving along the axis, and the heat generated by the electron beam 7 is transmitted to the lower surface of the metal lid 2 to melt the brazing material 6.

The metal lid 2 and the metallized metal layer 5
For example, the brazing material 6 disposed between
A joining material made of a tin alloy, a lead-tin alloy, an aluminum-silicon alloy, a copper-zinc alloy, a silver-copper-phosphorus alloy, a silver-indium-tin alloy, or the like, for joining the metal lid 2 to the metallized metal layer 5 When the heat generated by the electron beam 7 applied to the upper surface of the metal lid 2 is transmitted to the lower surface of the metal lid 2, the heat is received and melted.

When the brazing material 6 is disposed between the metal cover 2 and the metallized metal layer 5, the brazing material 6 is coated on the lower surface of the metal cover 2 in advance in order to improve the workability of the arrangement. Is being worn.

Further, in the electronic device according to the present invention, the electron beam welding for joining the metal lid 2 to the metallized metal layer 5 with the brazing material 6 interposed therebetween is performed by 50 μm or more inward from the outer periphery of the metal lid 2. Done in position. That is, the electron beam welding is performed by irradiating the electron beam 7 to a position on the upper surface of the metal lid 2 at a position inside the outer periphery of the metal lid 2 at a distance of 50 μm or more.

By adjusting the current, output, and moving speed of the electron beam 7 to appropriate values, FIG.
(A) and (b), as shown in an enlarged cross-sectional view of a main part, a flat metal lid 2 is placed with a brazing material 6 interposed between metallized metal layers 5, and the metal lid 2 is placed. From the outer circumference on the top of 2
When the electron beam 7 is irradiated to a position on the inner side of 50 μm or more, for example, a portion of the metal lid 2 on the outer peripheral side from the irradiation position of the electron beam 7 is upward about 10 to 20 ° by the action of heat by the electron beam 7. And a pool B of the brazing material 6 is formed between the metallized metal layer 5 and the outer peripheral side portion bent upward, and the metal cover 2 is formed by the brazing material 6 pool B. It will be firmly joined to the layer 5.

Here, by adjusting the current, output, moving speed, etc. of the electron beam 7 to appropriate values, the upper surface of the metal lid 2 is located at an inner position at least 50 μm away from the outer periphery of the metal lid 2. When the electron beam 7 is irradiated,
The portion of the metal lid 2 on the outer peripheral side from the irradiation position of the electron beam 7 is bent upward by the action of heat by the electron beam 7 because the portion of the metal lid 2 irradiated with the electron beam 7 is locally. Because of the high temperature, this portion tends to expand more thermally than other portions of the metal lid 2, so that the portion of the metal lid 2 closer to the outer peripheral side from the irradiation position of the electron beam 7. At the same time, a stress that tends to shrink toward the central portion acts, and at the same time, the current, output, and moving speed of the electron beam 7 are adjusted to appropriate values, so that the electron beam 7
Only the upper surface side of the irradiated portion is partially softened or melted and easily deformed by stress, and the metal cover 2 acts on the outer peripheral portion from the irradiation position of the electron beam 7 to the relatively central portion. It is considered that only the upper surface side of the portion of the metal lid 2 irradiated with the electron beam 7 is compressed and deformed due to the stress to be shrunk to the side.

The outer peripheral portion of the metal lid 2 joined to the metallized metal layer 5 is formed in a desired state by various processing methods in advance according to the specifications of the electronic device and the specifications and conditions of the electron beam welding. For example, it may be bent upward at an angle of about 10 to 20 degrees from a position 50 μm or more inward from the outer peripheral portion irradiated with the electron beam 7.

It should be noted that the metal cover 2 is not covered with the metallized metal layer 5.
When the electron beam welding for joining via the brazing material 6 is performed at a position of less than 50 μm inward from the outer periphery of the metal lid 2, the gap between the metal lid 2 and the metallized metal layer 5 is formed. Since a sufficient amount of the pool B of the brazing material 6 cannot be formed, the metal lid 2 and the metallized metal layer 5 cannot be firmly joined. Therefore, in the electronic device of the present invention, the electron beam welding for joining the metal lid 2 to the metallized metal layer 5 with the brazing material 6 interposed therebetween is performed at an inner position at least 50 μm away from the outer periphery of the metal lid 2. Limited to what is done.

Thus, according to the electronic device of the present invention, there can be obtained an electronic device in which the electronic component 3 is housed in a highly airtight and reliable state inside a container including the insulating base 1 and the metal lid 2.

[0034]

[Example] At the center of the upper surface, the length is 2.2 mm and the width is 0.2 mm
・ It has a substantially rectangular parallelepiped concave portion having a depth of 0.25 mm, and has a frame-shaped tungsten metallized metal layer having a width of 0.4 mm and a thickness of 20 μm surrounding the concave portion on the outer peripheral portion of the upper surface. The length is 3 mm and the width is 3 mm. An insulating substrate made of a substantially square flat aluminum oxide sintered body having a thickness of 2 mm and a thickness of 0.5 mm was prepared. And on the surface of the metallized metal layer,
A nickel plating layer having a thickness of 5 μm was applied by an electrolytic plating method.

Further, a brazing material having a thickness of 10 μm and consisting of 90% by weight of lead and 10% by weight of tin was applied to the entire lower surface by a cladding method. The length was 3 mm, the width was 2 mm, and the thickness was 0.1 mm.
A flat lid made of an iron-nickel-cobalt alloy plate was prepared.

Then, a lid is placed on the metallized metal layer of the insulating substrate with a brazing material interposed therebetween, and an electron beam having a power of 2.5 mA / 75 W and a diameter of 0.2 mm is applied to the upper surface of the metal lid. Irradiation is performed while moving along the metallized metal layer at a speed of 300 mm / sec at a position where the distance from the outer periphery to the value shown in Table 1 is applied, and thereby the brazing material is applied to the metalized metal layer. And joined by electron beam welding to obtain 25 samples of each sample. Note that among these samples, sample numbers 1 and 2
This is a comparative example for comparison with the example of the present invention, and is a sample outside the scope of the present invention.

Thereafter, these samples were subjected to a temperature cycle of −65 to 150 ° C. for 100 cycles, 200 cycles, and 50 cycles, respectively.
After exposure for 0 cycles and 1000 cycles, the US MIL-ST
An airtightness test was performed by a method according to D883C METHOD 1014.7 to confirm the presence or absence of poor airtightness. Table 1 shows the results.
Shown in

[0038]

[Table 1]

As shown in Table 1, in the sample numbers 1 and 2 of the comparative examples in which the irradiation position of the electron beam was less than 50 μm from the outer periphery of the metal lid, poor airtightness occurred up to 500 cycles. On the other hand, in the sample Nos. 3 to 6 of the examples of the present invention in which the irradiation position of the electron beam is 50 μm or more inside from the outer periphery of the metal lid, poor airtightness did not occur up to 1000 cycles. .

In each of Samples Nos. 3 to 6, the outer peripheral portion of the metal lid was bent upward, and the outer peripheral portion of the metal lid was bent upward and the metallized metal layer of the insulating base was formed. A large pool of brazing material was formed.

As can be seen from the above results, according to the electronic device of the present invention, the electron beam welding is performed at an inner position at least 50 μm away from the outer periphery of the metal lid. The outer portion from the electron beam irradiation position warps upward, and a large brazing material pool is formed between a portion bent above the outer peripheral portion of the metal lid and the metallized metal layer of the insulating base, thereby. The bonding strength of the metal lid to the metallized metal layer becomes strong, and the hermetic sealing of the container can be completed for a long period of time, and the electronic components housed therein can be operated normally and stably for a long period of time.

The present invention is not limited to the above-described embodiment, and it goes without saying that various changes can be made without departing from the scope of the present invention.

[0043]

According to the electronic device of the present invention, the electronic component is mounted on the mounting portion on the upper surface of the insulating base, and the brazing material is coated on the frame-shaped metallized metal layer attached so as to surround the mounting portion. An electronic device in which a metal lid is joined by electron beam welding via an electronic device, wherein the electron beam welding is performed at a position 50 μm or more inside the outer periphery of the metal lid, and the outer periphery of the metal lid is Since the portion is bent upward, a large brazing material pool is formed between the outer peripheral portion bent above the metal lid body and the metallized metal layer of the insulating base. The bonding strength of the body to the metallized metal layer becomes strong.

As described above, according to the present invention, a metal lid is firmly joined to a metallized metal layer of an insulating substrate by electron beam welding with a brazing material therebetween, and heat is repeatedly applied to the electronic device. Also, it was possible to provide an electronic device capable of operating the electronic components housed therein normally and stably for a long period of time without the metal lid being peeled off from the metallized metal layer of the insulating base.

[Brief description of the drawings]

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

FIGS. 2A and 2B are enlarged cross-sectional views of main parts for describing electron beam welding in the electronic device of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Insulating base 1a ... Mounting part 2 ... Metal lid 3 ... Electronic parts 5 Metallized metal layer 6 ... Brazing material 7 ... Electron beam

Claims (1)

[Claims] An electronic component is mounted on a mounting portion on an upper surface of an insulating substrate, and a metal lid is formed on a metallized metal layer in a frame shape surrounding the mounting portion via a brazing material. An electronic device joined by beam welding, wherein the electron beam welding is performed at a position 50 μm or more inside the outer periphery of the metal lid, and the outer periphery of the metal lid is bent upward. An electronic device, comprising: an electronic device;