JP3878836B2 - Package for pressure detection device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a pressure detection device package used in a pressure detection device for detecting pressure.
[0002]
[Prior art]
Conventionally, a capacitance type pressure detection device is known as a pressure detection device for detecting pressure. For example, as shown in a cross-sectional view in FIG. 2, the capacitance type pressure detection device is accommodated in a capacitance type pressure sensitive element 22 and a package 28 on a wiring substrate 21 made of a ceramic material or a resin material. And a semiconductor element 29 for operation. The pressure sensitive element 22 is made of, for example, an electrically insulating material such as a ceramic material, and has an insulating base 24 having a concave portion in which one electrode 23 for forming a capacitance is attached at the center of the upper face, and an upper face of the insulating base 24 The insulating plate 26 is joined in a flexible state so as to form a sealed space with the insulating base 24, and the other electrode 25 for forming a capacitance is attached to the lower surface, and each static plate Consists of external lead terminals 27 for electrically connecting the electrodes 23 and 25 for capacitance formation to the outside, and each capacitance is formed by bending the insulating plate 26 in response to external pressure. The capacitance formed between the electrodes 23 and 25 for use changes. Then, an external pressure can be detected by performing arithmetic processing on the change of the electrostatic capacitance with the semiconductor element 29 for arithmetic operation.
[0003]
[Problems to be solved by the invention]
However, according to this conventional pressure detection device, since the pressure sensitive element 22 and the semiconductor element 29 are individually mounted on the wiring board 21, the pressure detection device becomes large and the pressure detection electrode 23 is increased. The wiring between 25 and the semiconductor element 29 becomes long, and an unnecessary electrostatic capacity is formed between the long wiring, so that the sensitivity is low.
[0004]
Therefore, the applicant of the present application previously disclosed in Japanese Patent Application No. 2000-178618, an insulating base made of a ceramic material having a mounting portion on which a semiconductor element is mounted on one main surface, and disposed on and inside the surface of the insulating base. A plurality of wiring conductors to which the respective electrodes of the semiconductor element are electrically connected and a central portion of the other main surface of the insulating base, and are electrically connected to one of the wiring conductors. It is made of a ceramic material joined in a flexible state so as to form a sealed space between the first electrode for forming a capacitance and the other main surface of the insulating base and the central portion of the main surface. An insulating plate and a second electrode for forming a capacitance that is attached to the inner main surface of the insulating plate so as to face the first electrode and is electrically connected to the other one of the wiring conductors. A package for the pressure sensing device is proposed. According to this pressure detection device package, the first electrode for forming a capacitance is provided on the other main surface of the insulating base having the mounting portion on which the semiconductor element is mounted on one main surface. Since the insulating plate having the second electrode for forming the opposing capacitance on the inner surface is joined in a flexible state so as to form a sealed space between the other main surface of the insulating base, A pressure-sensitive element is integrally formed in a package that houses a semiconductor element. As a result, the pressure detection device can be reduced in size, and the wiring for connecting the pressure detection electrode and the semiconductor element can be shortened. Unnecessary capacitance generated between the wirings can be reduced.
[0005]
In the pressure detection device package proposed in Japanese Patent Application No. 2000-178618, for example, a frame body made of ceramics or metal is provided on the outer peripheral portion of the other main surface of the insulating base so as to surround the first electrode. In addition, the insulating plate was joined to the insulating base by brazing the outer peripheral portion of the second electrode onto the frame through a brazing material such as silver-copper brazing.
[0006]
However, according to the pressure detection device package proposed in Japanese Patent Application No. 2000-178618, the brazing material made of silver-copper brazing that joins the insulating base and the insulating plate is likely to be plastically deformed by a large stress. When a large external pressure is applied to the plate over a long period of time, the stress generated by the bending of the insulating plate acts greatly on the inner peripheral edge of the brazing material joining the insulating base and the insulating plate, and the brazing material becomes plastic. As a result, the insulation plate does not completely return to its original position even when the application of pressure is released, and the external pressure cannot be accurately detected. Was. In addition, when brazing the outer peripheral portion of the second electrode of the insulating plate onto a frame made of ceramics or metal via a brazing material such as silver-copper brazing, a part of the brazing material is in the center of the second electrode. In this way, the capacitance formed between the first electrode and the second electrode varies greatly due to the brazing material that has flowed out in this way, so that the external pressure can be accurately detected. Has the problem of being difficult.
[0007]
The present invention has been completed in view of the above-described problems, and an object of the present invention is to provide a pressure detection device capable of accurately detecting an external pressure over a long period of time.
[0008]
[Means for Solving the Problems]
The present invention provides a ceramic substrate having a first metallization electrode for forming a capacitance and a frame-shaped first metallization layer for bonding that surrounds the first metallization electrode on one main surface, and one main surface On the outer periphery of Frame-shaped protrusion With , Surrounded by the protrusion On the other side A second metallization electrode for forming a capacitance; and the protrusion Up And a ceramic plate having a frame-shaped second bonding metallization layer electrically connected to the second metallization electrode and brazed to the first bonding metallization layer. Preparation The first metallization electrode And the second metallized electrode The ceramic substrate and the ceramic plate Between It is formed Sealed space Opposite across And a package for a pressure detecting device in which the ceramic base and the ceramic plate are bonded so that the ceramic plate is in a flexible state, the metallizing layer for the first bonding and the second bonding for the second bonding. Each of the metallized layers has an inner circumference that is located 0.05 mm or more outside the inner circumference of the protrusion, and the second metallized electrode is fired together with a green ceramic molded body in which the metallized paste becomes the ceramic plate. It is formed.
The present invention also includes the pressure detection device package and a semiconductor element mounted on a main surface different from the main surface of the ceramic base on which the first metallized electrode is formed. The metallized electrode, and the semiconductor element and the second metallized electrode are electrically connected to each other.
In the present invention, the ceramic base further includes a first metallized wiring conductor that connects the semiconductor element and the first metallized electrode, and the first metallized wiring conductor includes the ceramic base inside the ceramic base. The base member extends in the thickness direction from the one main surface of the base to the main surface on which the semiconductor element is mounted, and the semiconductor element and the joint between the semiconductor element and the first metallized wiring conductor are sealed with resin. It is characterized by being sealed with a stopper.
[0009]
According to the pressure detection device package of the present invention, the inner periphery of each of the first bonding metallization layer provided on the ceramic substrate and the second bonding metallization layer provided on the protrusion of the ceramic plate is the protrusion of the ceramic plate. Since it is located 0.05 mm or more outside the inner periphery of the part, even if an external pressure is applied to the ceramic plate for a long period of time, the stress generated by the bending of the ceramic plate The brazing material that concentrates in the vicinity of the base and does not act significantly on the inner peripheral edge of the brazing material that joins the ceramic base and the ceramic plate, and the brazing material that joins the ceramic base and the ceramic plate flows out onto the second metallized electrode. There is nothing.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Next, the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is a cross-sectional view showing an example of an embodiment of a pressure detection device package according to the present invention, in which 1 is a ceramic substrate, 2 is a ceramic plate, and 3 is a semiconductor element.
[0011]
The ceramic substrate 1 is a laminated body made of a ceramic material such as an aluminum oxide sintered body, an aluminum nitride sintered body, a mullite sintered body, or a glass ceramic. For example, the ceramic substrate 1 may be made of an aluminum oxide sintered body. For example, an appropriate organic binder, solvent, plasticizer, and dispersant are added to and mixed with ceramic raw material powders such as aluminum oxide, silicon oxide, magnesium oxide, and calcium oxide to form a mud, and this is a well-known doctor blade method. Are formed into a sheet shape to obtain a plurality of ceramic green sheets, and then these ceramic green sheets are subjected to appropriate punching, laminating, and cutting processes to produce a raw ceramic for the ceramic substrate 1. A green body is obtained and the green ceramic green body is fired at a temperature of about 1600 ° C. It is manufactured by doing.
[0012]
The ceramic substrate 1 has a recess 1a for accommodating the semiconductor element 3 at the center of the lower surface thereof, thereby functioning as a container for accommodating the semiconductor element 3. The central portion of the bottom surface of the recess 1a is a mounting portion 1b on which the semiconductor element 3 is mounted. The semiconductor element 3 is mounted on the mounting portion 1b and the resin sealing such as an epoxy resin is provided in the recess 1a. The semiconductor element 3 is sealed by filling the material 4. In this example, the semiconductor element 3 is sealed by filling the recess 1a with the resin sealing material 4. However, the semiconductor element 3 has a lid made of metal or ceramics on the lower surface of the ceramic base 1 to form the recess 1a. It may be sealed by bonding so as to block.
[0013]
Also, a plurality of metallized wiring conductors 5 connected to the respective electrodes of the semiconductor element 3 are led out to the mounting portion 1b. The metallized wiring conductor 5 and the respective electrodes of the semiconductor element 3 are connected to a conductive material such as a solder bump 6 or the like. The electrodes of the semiconductor element 3 and the metallized wiring conductors 5 are electrically connected to each other through the conductive bonding member made of the semiconductor element 3 and the semiconductor element 3 is fixed to the mounting portion 1b. In this example, the electrode of the semiconductor element 3 and the metallized wiring conductor 5 are connected via the solder bumps 6. However, the electrode of the semiconductor element 3 and the metalized wiring conductor 5 are connected to other types of electric wires such as bonding wires. It may be connected by a general connection means.
[0014]
The metallized wiring conductor 5 functions as a conductive path for electrically connecting each electrode of the semiconductor element 3 to an external electric circuit and a first metallized electrode 7 and a second metallized electrode 9 to be described later, and a part thereof is a ceramic substrate. The other part is electrically connected to the first metallized electrode 7 and the second metallized electrode 9. Each electrode of the semiconductor element 3 is electrically connected to these metallized wiring conductors 5 through a conductive bonding material and the semiconductor element 3 is sealed with a resin sealing material 4. The portion led out to the lower surface of the outer periphery of the ceramic substrate 1 is joined to the wiring conductor of the external electric circuit board via a conductive bonding material such as solder, so that the semiconductor element 3 accommodated therein is electrically connected to the external electric circuit. Will be.
[0015]
Such a metallized wiring conductor 5 is made of metal powder metallization such as tungsten, molybdenum, copper, or silver, and is obtained by adding and mixing an appropriate organic binder, solvent, plasticizer, dispersant, or the like to metal powder such as tungsten. The metallized paste is printed and applied in a predetermined pattern on a ceramic green sheet for the ceramic substrate 1 by employing a conventionally known screen printing method, and is fired together with a green ceramic molded body for the ceramic substrate 1 to thereby form the ceramic substrate 1. A predetermined pattern is formed inside and on the surface. In order to prevent the metallized wiring conductor 5 from being oxidized and corroded on the surface of the metallized wiring conductor 5 and to improve the bonding between the metalized wiring conductor 5 and a conductive bonding material such as solder, it is usual. If present, a nickel plating layer having a thickness of about 1 to 10 μm and a gold plating layer having a thickness of about 0.1 to 3 μm are sequentially deposited.
[0016]
A first metallized electrode 7 for forming a capacitance is attached to the center of the upper surface of the ceramic substrate 1. The first metallized electrode 7 is for forming a capacitance for a pressure sensitive element together with a second metallized electrode 9 to be described later, and is formed in a substantially circular pattern, for example. The first metallized electrode 7 is connected to one of the metallized wiring conductors 5a, whereby the electrode of the semiconductor element 3 is connected to the metallized wiring conductor 5a via a conductive bonding material such as a solder bump 6. When connected, the electrode of the semiconductor element 3 and the first metallized electrode 7 are electrically connected.
[0017]
Such a first metallized electrode 7 is made of metal powder metallization of tungsten, molybdenum, copper, silver or the like having a thickness of about 10 to 50 μm, and an organic binder, solvent, plasticizer, or dispersant suitable for the metal powder such as tungsten. The metallized paste obtained by adding and mixing is printed and applied to a ceramic green sheet for the ceramic substrate 1 using a conventionally known screen printing method, and this is fired together with a green ceramic molded body for the ceramic substrate 1 to form a ceramic. A predetermined pattern is formed at the center of the upper surface of the substrate 1. In addition, in order to prevent the first metallized electrode 7 from being oxidized and corroded, a nickel plating layer having a thickness of about 1 to 10 μm is usually applied to the surface of the first metallized electrode 7.
[0018]
Further, a first bonding metallization layer 8 having a substantially circular or octagonal frame shape surrounding the first metallization electrode 7 is attached to the outer peripheral portion of the upper surface of the ceramic substrate 1. The first bonding metallization layer 8 functions as a base metal for bonding the ceramic plate 2 to the ceramic substrate 1, and the first bonding metallization layer 8 has a second metallization electrode 9 and the second metallization electrode on the lower surface. A ceramic plate 2 having a second bonding metallization layer 10 electrically connected to 9 is connected to the second bonding metallization layer 10 and the first bonding metallization layer 8 via a brazing material 11 such as silver-copper brazing. They are joined by brazing.
[0019]
One metallized wiring conductor 5b is connected to the first metallizing layer 8 for bonding, whereby the electrode of the semiconductor element 3 is connected to the metallized wiring conductor 5b via a conductive bonding material such as a solder bump 6. When electrically connected, the electrode of the semiconductor element 3 and the second metallized electrode 9 are electrically connected.
[0020]
The metallization layer 8 for the first bonding is made of metal powder metallization such as tungsten, molybdenum, copper or silver, and an appropriate organic binder, solvent, plasticizer or dispersant is added to and mixed with metal powder such as tungsten. The obtained metallized paste is printed and applied to a ceramic green sheet for the ceramic substrate 1 by employing a conventionally known screen printing method, and this is fired together with a green ceramic molded body for the ceramic substrate 1, whereby the outer periphery of the upper surface of the ceramic substrate 1 A predetermined frame-like pattern is formed on the part.
[0021]
The first bonding metallization layer 8 is prevented from being oxidized and corroded on the surface of the first bonding metallization layer 8 and the bonding between the first bonding metallization layer 8 and the brazing material 11 is made strong. Therefore, usually, a nickel plating layer having a thickness of about 1 to 10 μm is applied.
[0022]
The ceramic plate 2 attached to the upper surface of the ceramic substrate 1 is substantially square or octagon made of a ceramic material such as an aluminum oxide sintered body, an aluminum nitride sintered body, a mullite sintered body, or a glass ceramic. Alternatively, it is a substantially flat plate such as a circle, and has a frame-shaped protrusion 2a on the outer peripheral portion of its inner main surface. Then, it functions as a so-called pressure detection diaphragm in which a central portion thereof bends to the ceramic base 1 side according to an external pressure.
[0023]
The ceramic plate 2 has a small mechanical strength when the thickness of the central portion is less than 0.01 mm. Therefore, there is a high risk of being destroyed when a large external pressure is applied to the ceramic plate 2. On the other hand, if the thickness of the central portion exceeds 5 mm, it becomes difficult to bend with a small pressure, making it unsuitable as a pressure detecting diaphragm. Therefore, the thickness of the central part of the ceramic plate 2 is preferably in the range of 0.01 to 5 mm. If the height of the protrusion 2a is less than 0.01 mm, the gap formed between the ceramic substrate 1 and the ceramic plate 2 becomes too narrow, and the first metallization is applied when pressure is applied to the ceramic plate 2. There is a great risk that the electrode 7 and the second metallized electrode 9 come into contact with each other. On the other hand, if the height of the protrusion 2a exceeds 5 mm, the gap between the first metallized electrode 7 and the second metallized electrode 9 is increased. The formed capacitance becomes small, and the sensitivity of the pressure sensitive element is lowered. Therefore, the height of the protrusion 2a is preferably in the range of 0.01 to 5 mm.
[0024]
If such a ceramic plate 2 is made of, for example, an aluminum oxide sintered body, a suitable organic binder, solvent, plasticizer, dispersion for ceramic raw material powder such as aluminum oxide, silicon oxide, magnesium oxide, calcium oxide, etc. A ceramic green sheet is obtained by adding a mixing agent to form a slurry, and forming this into a sheet by employing a conventionally known doctor blade method. After that, an appropriate punching process or The green ceramic molded body for the ceramic plate 2 is obtained by cutting, and the green ceramic molded body is manufactured by firing at a temperature of about 1600 ° C.
[0025]
Further, a second metallized electrode 9 for forming a capacitance facing the first metallized electrode 7 is attached to the lower surface of the ceramic plate 2 at the center thereof. The second metallized electrode 9 is for forming a capacitance for a pressure sensitive element together with the first metallized electrode 7 described above, and is formed in a substantially circular pattern, for example.
[0026]
Such a second metallized electrode 9 is made of metal powder metallization of tungsten, molybdenum, copper, silver or the like having a thickness of about 10 to 50 μm, and suitable organic binder, solvent, plasticizer, dispersant for the metal powder such as tungsten. The metallized paste obtained by adding and mixing is printed on a ceramic green sheet for the ceramic plate 2 by using a conventionally well-known screen printing method, and fired together with a green ceramic molded body for the ceramic plate 2 to be ceramic. A predetermined pattern is formed at the center of the lower surface of the plate 2. In order to prevent the second metallized electrode 9 from being oxidatively corroded, a nickel plating layer having a thickness of about 1 to 10 μm is usually applied to the surface of the second metallized electrode 9.
[0027]
Further, a substantially circular or substantially octagonal frame-like second bonding metallization layer 10 electrically connected to the second metallization electrode 9 is deposited on the lower surface of the protrusion 2 a of the ceramic plate 2. The second bonding metallization layer 10 functions as a bonding base metal layer for bonding the ceramic plate 2 to the ceramic substrate 1, and the second bonding metallization layer 10 and the first bonding metallization layer 8 are silver- The ceramic base 1 and the ceramic plate 2 are joined by brazing via a brazing material 11 such as copper brazing, and the first joining metallized layer 8 and the second joining metallized layer 10 are electrically connected. At the same time, a sealed space is formed between the ceramic substrate 1 and the ceramic plate 2.
[0028]
At this time, the first metallized electrode 7 and the second metallized electrode 9 are opposed to each other with a sealed space formed between the ceramic base 1 and the ceramic plate 2 interposed therebetween. A predetermined capacitance is formed according to the area of the electrode 7 or the second metallized electrode 9 and the distance between the first metallized electrode 7 and the second metallized electrode 9. When an external pressure is applied to the upper surface of the ceramic plate 2, the ceramic plate 2 is bent toward the ceramic base 1 in accordance with the pressure, and the interval between the first metallized electrode 7 and the second metallized electrode 9 is changed. As a result, the capacitance between the first metallized electrode 7 and the second metallized electrode 9 changes, so that it functions as a pressure-sensitive element that senses a change in external pressure as a change in capacitance. Then, the change in electrostatic capacity is transmitted to the semiconductor element 3 accommodated in the recess 1a through the metallized wiring conductors 5a and 5b, and this is processed by the semiconductor element 3 so as to know the magnitude of the external pressure. be able to.
[0029]
The second bonding metallization layer 10 is made of metal powder metallization of tungsten, molybdenum, copper, silver, etc. with a thickness of about 10-50 μm, and suitable organic binder, solvent, plasticizer, dispersion for metal powder such as tungsten. The metallized paste obtained by adding and mixing the agent is printed and applied to a ceramic green sheet for the ceramic plate 2 using a conventionally known screen printing method, and is fired together with the green ceramic molded body for the ceramic plate 2 The ceramic plate 2 is formed in a predetermined pattern on the lower surface of the protrusion 2a.
[0030]
Further, in order to join the ceramic plate 2 to the ceramic substrate 1, nickel plating layers having a thickness of about 1 to 10 μm are respectively deposited on the surfaces of the first joining metallization layer 8 and the second joining metallization layer 10. The ceramic substrate 1 and the ceramic plate 2 are sandwiched between a first bonding metallization layer 8 and a second bonding metallization layer 10 with a brazing material foil made of silver-copper brazing having a thickness of about 10 to 200 μm. A method is used in which the first bonding metallized layer 8 and the second bonding metallized layer 10 are brazed by superimposing and heating them to a temperature of about 850 ° C. in a reducing atmosphere to melt the brazing material foil. .
[0031]
In order to prevent the second bonding metallization layer 10 from being oxidatively corroded on the surface of the second bonding metallization layer 10, and to improve the bonding between the second bonding metallization layer 10 and the brazing material 11 Normally, a nickel plating layer having a thickness of about 1 to 10 μm is applied.
[0032]
In the present invention, the inner peripheries of the first joining metallized layer 8 and the second joining metallized layer 10 are located 0.05 mm or more outside the inner circumference of the protrusion 2a of the ceramic plate 2, This is very important. Since the inner periphery of each of the first bonding metallization layer 8 and the second bonding metallization layer 10 is located 0.05 mm or more outside from the inner periphery of the protrusion 2a, the ceramic plate 2 is greatly bent by external pressure. Even so, the stress generated by the bending is largely concentrated in the vicinity of the root of the inner periphery of the protrusion 2a, and does not act greatly on the inner peripheral edge of the brazing material 11. Therefore, according to the package for a pressure detection device of the present invention, even if a large external pressure is applied to the ceramic plate 2 over a long period of time, no plastic deformation occurs in the brazing material 11, and the external pressure is increased. It is possible to provide a pressure detection device capable of accurately detecting over a period. Further, since the inner peripheries of the first bonding metallization layer 8 and the second bonding metallization layer 10 are located outside the inner periphery of the protrusion 2a by 0.05 mm or more, the protrusions are used to increase the sensitivity of the pressure sensitive element. Even when the thickness of the portion 2a is as thin as 0.05 mm or less, for example, a gap of 0.05 mm or more is provided between the first bonding metallization layer 8 and the second bonding metallization layer 10 and the second metallization electrode 9. As a result, when the first bonding metallization layer 8 and the second bonding metallization layer 10 are brazed via a brazing material 11 such as silver-copper brazing, the brazing material 11 is second. Flowing out to the metallized electrode 9 is effectively prevented.
[0033]
Note that the first bonding metallization layer 8 and the second bonding metallization layer 10 have the ceramic plate 2 exposed to an external pressure when the inner circumference is located outside the inner circumference of the protrusion 2a by less than 0.05 mm. A large amount of stress generated when the brazing material 11 is greatly bent is applied to the inner peripheral edge of the brazing material 11 to increase the risk of plastic deformation of the brazing material 11 and the stress is applied to the inner peripheral side surface of the protrusion 2a. The risk of cracks and chipping occurring in the ceramic plate 2 is increased by being largely applied to the corner between the lower surface. At the same time, when the thickness of the protrusion 2a is as thin as 0.05 mm or less, for example, when the brazing material 11 brazes the first joining metallized layer 8 and the second joining metallized layer 10 through the brazing material 11, The danger of flowing out onto the second metallized electrode 9 becomes large. Therefore, the positions of the inner circumferences of the first bonding metallization layer 8 and the second bonding metallization layer 10 are specified at positions outside the inner circumference of the protrusion 2a by 0.05 mm or more.
[0034]
Thus, according to the package for a pressure detection device of the present invention, the first metallized electrode 7 for forming a capacitance is formed on the other main surface of the ceramic substrate 1 on which the semiconductor element 3 is mounted on one main surface. In addition, the ceramic plate 2 having the second metallized electrode 9 for forming a capacitance facing the first metallized electrode 7 on the inner surface is flexible so as to form a sealed space between the ceramic substrate 1 and the ceramic plate 2. Since the bonding is performed, the container for housing the semiconductor element 3 and the pressure-sensitive element are integrated, and as a result, the pressure detection device can be reduced in size. In addition, since the first metallized electrode 7 and the second metallized electrode 9 for forming capacitance are connected to the semiconductor element 3 via the metallized wiring conductors 5a and 5b provided on the ceramic substrate 1, the first metallized electrode 7 And the second metallized electrode 9 can be connected to the semiconductor element 3 at a short distance. As a result, an unnecessary capacitance generated between the metallized wiring conductors 5a and 5b is reduced, and the pressure detecting device is highly sensitive. Can be provided.
[0035]
Thus, according to the above-described package for the pressure detection device, the semiconductor element 3 is mounted on the mounting portion 1b, and each electrode of the semiconductor element 3 and the metallized wiring conductor 5 are electrically connected. By sealing, the pressure detection device is small and has high sensitivity.
[0036]
In addition, this invention is not limited to an example of the above-mentioned embodiment, It cannot be overemphasized that a various change is possible if it is a range which does not deviate from the summary of this invention.
[0037]
【The invention's effect】
As described above, according to the pressure detection device package of the present invention, the inner periphery of each of the first bonding metallization layer and the second bonding metallization layer for bonding the ceramic base and the ceramic plate is the ceramic plate. Since it is located 0.05 mm or more outside the inner periphery of the protrusion, even if an external pressure is applied to the ceramic plate for a long period of time, the stress generated by the bending of the ceramic plate It is concentrated in the vicinity of the peripheral root and does not act greatly on the inner peripheral edge of the brazing material joining the ceramic base and the ceramic plate, so plastic deformation occurs in the brazing material joining the ceramic base and the ceramic plate. As a result, the ceramic plate returns completely to its original position when the application of pressure is released. At the same time, the brazing material joining the ceramic substrate and the ceramic plate does not flow out onto the second metallized electrode. Therefore, it is possible to provide a pressure detection device that can accurately detect the external pressure over a long period of time.
In addition, the pressure-sensitive element is integrally formed in the package that accommodates the semiconductor element, and as a result, the pressure detection device can be miniaturized and the wiring for connecting the pressure detection electrode and the semiconductor element is short, Unnecessary capacitance generated between these wirings can be reduced.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing an example of an embodiment of a package for a pressure detection device of the present invention.
FIG. 2 is a cross-sectional view showing a conventional pressure detection device.
[Explanation of symbols]
1 ... Ceramic substrate
2. Ceramic plate
2a ... Projection
3. Semiconductor device
7. First metallized electrode
8 ... Metalized layer for first bonding
9 ... Second metallized electrode
10 ・ ・ ・ ・ ・ Metalized layer for second bonding
11 Brazing material

Claims (3)

A ceramic base having a first metallization electrode for forming a capacitance and a frame-shaped first metallization layer for bonding that surrounds the first metallization electrode on the main surface;
And having a frame-like protrusions on the outer peripheral portion of the one main surface has a second metallized electrode for electrostatic capacity formed on one main surface surrounded by the protrusion portion,
Further on the protrusion, it is electrically connected to the second metallized electrode, and provided with a ceramic plate having a second bonding metallized layer of brazed frame shape to said first bonding metallized layer,
Said second metallized electrode and the first metallized electrode, the facing sides of the ceramic substrate and hermetically sealed space formed between the ceramic plate, and so that the ceramic plate is flexible state, the A package for a pressure detection device in which a ceramic substrate and the ceramic plate are joined,
The first bonding metallization layer and the second bonding metallization layer are located on the outer side of the inner periphery of the protrusions by 0.05 mm or more, respectively.
The second metallized electrode is formed by firing a metallized paste together with a green ceramic molded body serving as the ceramic plate. A package for a pressure detection device according to claim 1;
A semiconductor element mounted on a main surface different from the main surface on which the first metallized electrode of the ceramic base is formed,
The pressure detecting device, wherein the semiconductor element and the first metallized electrode, and the semiconductor element and the second metallized electrode are electrically connected to each other. The ceramic base includes a first metallized wiring conductor that connects the semiconductor element and the first metallized electrode,
The first metallized wiring conductor extends in the thickness direction from the one main surface of the ceramic base to the main surface on which the semiconductor element is mounted, and the semiconductor element and the semiconductor The pressure detection device according to claim 2, wherein a joint portion between the element and the first metallized wiring conductor is sealed with a resin sealing material.

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