JP2003065869A - Package for pressure detection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a small-sized and highly-sensitive pressure detection device capable of detecting the outside pressure accurately over a long period. SOLUTION: This package for the pressure detection device comprises a ceramic substrate 1 having plural metallized wiring conductors 6, and having a loading part 1b of a semiconductor element 4 on one main surface and a first metallized electrode 8 for capacitance formation connected electrically to the metallized wiring conductors 6 on the other main surface, a ceramic board 2 jointed to the ceramic substrate 1 in the flexible state so as to form an enclosed space S between itself and the other main surface of the ceramic substrate 1, and having a second metallized electrode 10 facing to the first metallized electrode 8 on its inside main surface, and a protection board 3 disposed so as to have a gap G between the outside main surface of the ceramic board 2 and the outside main surface thereof, and having a through hole 3a penetrating from the outside to the gap G.

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pressure detecting device package used for a pressure detecting device for detecting pressure. 2. Description of the Related Art Conventionally, a capacitance type pressure detecting device has been known as a pressure detecting device for detecting pressure. As shown in a sectional view of FIG. 5, for example, a capacitance type pressure sensing element 22 and a package 28 are provided on a wiring board 21 made of a ceramic material or a resin material.
And a semiconductor element 29 for arithmetic operation housed in the computer. The pressure-sensitive element 22 is made of, for example, an electrically insulating material such as a ceramic material.
An insulating substrate 24 having a concave portion to which
An insulating plate 26, which is joined in a flexible state on the upper surface of the insulating substrate 24 so as to form a sealed space between the insulating substrate 24 and the other electrode 25 for forming a capacitance on the lower surface, Each of the electrodes 23 and 25 for forming a capacitance includes an external lead terminal 27 for electrically connecting the electrode to the outside, and each of the capacitances is formed by bending the insulating plate 26 according to an external pressure. The capacitance formed between the forming electrodes 23 and 25 changes. An external pressure can be detected by subjecting this change in capacitance to arithmetic processing by the semiconductor element 29 for arithmetic operation. [0003] However, according to this conventional pressure detecting device, the pressure-sensitive element 22 and the semiconductor element 29 are not provided.
Are individually mounted on the wiring board 21, which increases the size of the pressure detection device and the pressure detection electrode.
The wiring between 23 and 25 and the semiconductor element 29 becomes longer,
There is a problem that the sensitivity is low because an unnecessary capacitance is formed between the long wires. Accordingly, the applicant of the present application has previously filed Japanese Patent Application No. 2000-178.
618, an insulating substrate having a mounting portion on which a semiconductor element is mounted on one main surface; and a plurality of wiring conductors disposed on and inside the insulating substrate and electrically connected to respective electrodes of the semiconductor element. A first electrode for forming a capacitance, which is attached to a central portion of the other main surface of the insulating base and is electrically connected to one of the wiring conductors; An insulating plate joined in a flexible state so as to form a sealed space with the central portion of the main surface; and an inner main surface of the insulating plate is attached to the first main surface so as to face the first electrode. A pressure sensing device package including a second electrode for forming a capacitance electrically connected to another one is proposed. According to the pressure detecting device package, a first electrode for forming a capacitance is provided on the other main surface of the insulating base having a mounting portion on which a semiconductor element is mounted on one main surface, and the first electrode Since the insulating plate having the opposing second electrode for capacitance formation on the inner surface thereof was joined in a flexible state so as to form a sealed space between the other main surface of the insulating base, The pressure-sensitive element is formed integrally with the package containing the semiconductor element. As a result, the pressure detection device can be made small and the wiring connecting the electrode for pressure detection and the semiconductor element is shortened. Unnecessary capacitance generated between the wirings can be reduced. However, according to the package for a pressure detecting device proposed in Japanese Patent Application No. 2000-178618, the insulating plate is made of a brittle ceramic material. When the thickness is as thin as possible, cracks or cracks are likely to occur in the insulating plate when the external pressure applied to the insulating plate changes drastically or when a foreign object collides, etc. When such cracks and cracks occur, the hermeticity of the sealed space between the insulating base and the insulating plate is reduced, and as a result, the external pressure cannot be accurately detected. Had a point. The present invention has been completed in view of the above-mentioned problems, and has as its object to provide a pressure detection device which is small in size, has high sensitivity, and is capable of accurately detecting external pressure for a long period of time. It is to provide a device. A package for a pressure detecting device according to the present invention has a plurality of metallized wiring conductors inside and on the surface, and has a mounting portion on which a semiconductor element is mounted on one main surface and the other. A closed space is formed between a ceramic base having a first metallized electrode for forming a capacitance electrically connected to one of the metallized wiring conductors on the main surface of the ceramic base, and the other main surface of the ceramic base. As described above, the second metallized electrode is joined to the ceramic base in a flexible state, and has a second metallized electrode facing the first metallized electrode on its inner main surface and electrically connected to another one of the metallized wiring conductors. A ceramic plate and a ceramic plate are disposed so as to cover an outer main surface of the ceramic plate with a gap between the ceramic plate and the outer main surface, and a through-hole that partially communicates with the gap from outside is provided. And a protective plate. According to the package for a pressure detecting device of the present invention, a protective plate having a gap with the outer main surface of the ceramic plate and having a through hole from the outside to the gap is provided on the outer main surface of the ceramic plate. Even if the external pressure changes suddenly or a foreign object collides, the impact of the pressure or the foreign object is greatly reduced by the protective plate. Cracks and cracks can be effectively prevented. Next, the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is a cross-sectional view illustrating an example of an embodiment of a package for a pressure detection device according to the present invention.
1 is a ceramic base, 2 is a ceramic plate, 3 is a protection plate,
4 is a semiconductor element. The ceramic substrate 1 is made of a ceramic material such as an aluminum oxide sintered body, an aluminum nitride sintered body, a mullite sintered body, a silicon carbide sintered body, a silicon nitride sintered body, and a glass-ceramic. A laminate comprising
For example, if it is made of an aluminum oxide sintered body, aluminum oxide, silicon oxide, magnesium oxide,
A ceramic raw material powder such as calcium oxide is mixed with an appropriate organic binder, a solvent, a plasticizer, and a dispersant to form a slurry, which is formed into a sheet by using a conventionally known doctor blade method. A plurality of ceramic green sheets are obtained, and thereafter, these ceramic green sheets are subjected to appropriate punching, laminating, and cutting to obtain a green ceramic molded body for the ceramic substrate 1. About 1600 ° C
It is manufactured by firing at a temperature of The ceramic base 1 has a concave portion 1a for accommodating the semiconductor element 4 in the center of the lower surface thereof, and thereby functions as a container for accommodating the semiconductor element 4. The center of the bottom surface of the concave portion 1a is a mounting portion 1b on which the semiconductor element 4 is mounted.
The semiconductor element 4 is sealed by mounting the semiconductor element 4 on the substrate b and filling the recess 1a with a resin sealing material 5 such as an epoxy resin. In this example, the semiconductor element 4 is sealed by filling a resin sealing material 5 into the recess 1a. However, the semiconductor element 4 is provided with a lid made of metal or ceramic on the lower surface of the ceramic base 1 in the recess 1a. May be sealed by joining them so as to close them. A plurality of metallized wiring conductors 6 connected to the respective electrodes of the semiconductor element 4 are led out from the mounting portion 1b. The metallized wiring conductor 6 and the respective electrodes of the semiconductor element 4 are connected to the solder bumps 7 and the like. The electrodes of the semiconductor element 4 and the metallized wiring conductors 6 are electrically connected to each other, and the semiconductor element 4 is fixed to the mounting portion 1b. In this example, the electrode of the semiconductor element 4 and the metallized wiring conductor 6
Are connected via the solder bumps 7, but the semiconductor element 4
May be connected to the metallized wiring conductor 6 by another kind of electrical connection means such as a bonding wire. The metallized wiring conductor 6 functions as a conductive path for electrically connecting each electrode of the semiconductor element 4 to an external electric circuit and a first metallized electrode 8 and a second metallized electrode 10, which will be described later. Is led out to the lower surface of the outer periphery of the ceramic base 1, and another part is electrically connected to the first metallized electrode 8 and the second metallized electrode 10. Then, each electrode of the semiconductor element 4 is electrically connected to the metallized wiring conductor 6 through an electrical connection means such as a solder bump 7 and the semiconductor element 4 is sealed with a resin sealing material 5. By joining a portion of the metallized wiring conductor 6 extending to the lower surface of the outer periphery of the ceramic base 1 to a wiring conductor of an external electric circuit board via a conductive bonding material such as solder, the semiconductor element 4 housed inside is connected to the external electric circuit. It will be electrically connected. Such a metallized wiring conductor 6 is made of metallized metal powder such as tungsten, molybdenum, copper, silver or the like. A suitable organic binder, solvent, plasticizer, dispersant or the like is added to metal powder such as tungsten and mixed. The metallized paste thus obtained is printed and applied in a predetermined pattern on a ceramic green sheet for the ceramic substrate 1 by employing a conventionally well-known screen printing method, and is fired together with the green ceramic molded body for the ceramic substrate 1 to obtain a ceramic. A predetermined pattern is formed inside and on the surface of the base 1. The exposed surface of the metallized wiring conductor 6 is usually formed on the exposed surface of the metallized wiring conductor 6 to prevent the metallized wiring conductor 6 from being oxidized and corroded and to improve the bonding between the metallized wiring conductor 6 and a conductive bonding material such as solder. If so, the nickel plating layer having a thickness of about 1 to 10 μm and the thickness of 0.1 to
A gold plating layer of about 3 μm is sequentially applied. A recess 1c for forming a closed space having a depth of about 0.01 to 5 mm is formed in the center of the upper surface of the ceramic base 1. The concave portion 1c is for forming a closed space S between the concave portion 1c and the ceramic plate 2, and a first metallized electrode 8 for forming a capacitance is attached to the bottom surface of the concave portion 1c. Have been. The first metallized electrode 8 is for forming a capacitance for a pressure-sensitive element together with a second metallized electrode 10 described later, and is formed, for example, in a substantially circular pattern. One of the metallized wiring conductors 6a is connected to the first metallized electrode 8 so that the electrode of the semiconductor element 4 is connected to the metallized wiring conductor 6a via an electrical connection means such as a solder bump 7. When connected, the electrode of the semiconductor element 4 and the first metallized electrode 8 are electrically connected. The first metallized electrode 8 is made of metallized metal powder such as tungsten, molybdenum, copper, silver or the like. The metallized paste thus obtained is printed and applied to a ceramic green sheet for the ceramic substrate 1 by employing a conventionally well-known screen printing method, and is fired together with the green ceramic molded body for the ceramic substrate 1 to thereby form recesses in the ceramic substrate 1. 1c is formed in a predetermined pattern on the bottom surface. In addition, in order to prevent the first metallized electrode 8 from being oxidized and corroded, the exposed surface of the first metallized electrode 8 is usually
A nickel plating layer having a thickness of about 1 to 10 μm is applied. A frame-shaped first bonding metallization layer 9 is attached over the entire periphery of the concave portion 1c on the upper surface of the ceramic base 1, and the first bonding metallization layer 9 has a A ceramic plate 2 having a second metallized electrode 10 and a second metallized layer 11 for bonding is bonded via a conductive bonding material such as a silver-copper brazing material. One of the metallized wiring conductors 6b is connected to the first bonding metallized layer 9 so that the electrodes of the semiconductor element 4 can be electrically connected to the metallized wiring conductor 6b such as solder bumps 7 or the like. And the second metallized electrode 10 and the electrode of the semiconductor element 4 are electrically connected via the metallized wiring conductor 6b, the first metallized layer 9 for bonding and the metallized layer 11 for second bonding. It has become. The first bonding metallization layer 9 is made of metal powder metallization such as tungsten, molybdenum, copper, silver or the like.
A metallized paste obtained by adding and mixing a solvent, a plasticizer and a dispersant is printed and applied on a ceramic green sheet for the ceramic substrate 1 by employing a conventionally known screen printing method, and this is formed into a green ceramic for the ceramic substrate 1. By firing together with the body, a predetermined frame-shaped pattern is formed around the concave portion 1c on the upper surface of the ceramic base 1. The exposed surface of the first bonding metallization layer 9 prevents the first bonding metallization layer 9 from being oxidized and corroded and firmly bonds the first bonding metallization layer 9 to the conductive bonding material. Usually, the thickness is 1 to 10
A nickel plating layer of about μm is applied. A recess 1 is formed on the upper surface of the ceramic base 1.
The ceramic plate 2 is joined so as to form a closed space S with the ceramic plate 2c. The ceramic plate 2 is a substantially flat plate having a thickness of 0.01 to 5 mm and made of a ceramic material such as an aluminum oxide sintered body, an aluminum nitride sintered body, a mullite sintered body, and a glass-ceramic. It functions as a so-called pressure detection diaphragm that flexes accordingly. The ceramic plate 2 has a thickness of 0.01.
If it is less than 5 mm, its mechanical strength will be small, and the danger of being destroyed when a large external pressure is applied thereto will be great.
If it exceeds m, it becomes difficult to bend under a small pressure, and it becomes unsuitable as a diaphragm for pressure detection. Therefore, the thickness of the ceramic plate 2 is preferably in the range of 0.01 to 5 mm, and 0.01 to 5 mm in order to improve the sensitivity of pressure detection.
A range of 0.5 mm is more preferable. When such a ceramic plate 2 is made of, for example, an aluminum oxide sintered body, an organic binder, a solvent, and a plastic suitable for ceramic raw material powder such as aluminum oxide, silicon oxide, magnesium oxide, and calcium oxide. A ceramic green sheet is obtained by adding and mixing an agent and a dispersing agent to form a slurry and forming this into a sheet by employing a conventionally known doctor blade method.
Thereafter, the ceramic green sheet is subjected to appropriate punching and cutting to obtain a green ceramic molded body for the ceramic plate 2 and to fire the green ceramic molded body at a temperature of about 1600 ° C. . In the center of the lower surface of the ceramic plate 2,
A substantially circular second metallized electrode 10 for forming a capacitance is provided. This second metallized electrode 10 functions as an electrode for forming a capacitance for a pressure-sensitive element together with the first metallized electrode 8 described above. The second metallized electrode 10 is made of metal powder such as tungsten, molybdenum, copper, silver or the like. The metallized paste obtained as described above is printed and applied to a ceramic green sheet for the ceramic plate 2 by employing a conventionally known screen printing method, and is fired together with a green ceramic molded body for the ceramic plate 2 to thereby obtain a lower surface of the ceramic plate 2. Is formed in a predetermined pattern at the center of the. In addition, in order to prevent the second metallized electrode 10 from being oxidized and corroded, a nickel plating layer having a thickness of about 1 to 10 μm is usually applied to the exposed surface of the second metallized electrode 10. . Further, a frame-shaped second bonding metallization layer 11 electrically connected to the second metallization electrode 10 is attached to the outer peripheral portion of the lower surface of the ceramic plate 2. This second metallization layer 11 for bonding functions as a bonding base metal layer for bonding the ceramic plate 2 to the ceramic base 1,
First bonding metallization layer 9 and second bonding metallization layer 11
And a metal plate via a conductive bonding material such as silver-copper brazing, whereby the ceramic plate 2 is bonded to the ceramic base 1, and the metallized wiring conductor 6b and the second metallized electrode are joined together.
10 is electrically connected. The second bonding metallization layer 11 is
Metallization paste made of metal powders such as tungsten, molybdenum, copper, silver, etc., and metallized paste obtained by adding and mixing an appropriate organic binder, solvent, plasticizer, and dispersant to metal powders such as tungsten. Adopted and printed on a ceramic green sheet for the ceramic plate 2, and baked with a green ceramic molded body for the ceramic plate 2 to form a predetermined pattern on the outer peripheral portion of the lower surface of the ceramic plate 2. In addition, on the surface of the second bonding metallization layer 11, in order to prevent the second bonding metallization layer 11 from being oxidized and corroded, and to improve the bonding between the second bonding metallization layer 11 and the conductive bonding material. Usually, a nickel plating layer having a thickness of about 1 to 10 μm is applied. At this time, the first metallized electrode 8 and the second metallized electrode 10 are opposed to each other with a closed space S formed between the ceramic base 1 and the ceramic plate 2 therebetween. A predetermined capacitance is formed according to the area of the first metallized electrode 8 or the second metallized electrode 10 and the distance between the first metallized electrode 8 and the second metallized electrode 10. Then, when an external pressure is applied to the upper surface of the ceramic plate 2, the ceramic plate 2 bends toward the ceramic base 1 according to the pressure, and the distance between the first metallized electrode 8 and the second metallized electrode 10 changes, As a result, the capacitance between the first metallized electrode 8 and the second metallized electrode 10 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 the capacitance is transmitted to the semiconductor element 4 accommodated in the recess 1a via the metallized wiring conductors 6a and 6b, and the magnitude of the external pressure is known by performing arithmetic processing on the semiconductor element 4. be able to. When the distance between the first metallized electrode 8 and the second metallized electrode 10 is less than 0.01 mm at 1 atm, when a large pressure is applied to the ceramic plate 2,
There is a risk that the first metallized electrode 8 and the second metallized electrode 10 come into contact with each other and the pressure cannot be detected. On the other hand, if it exceeds 5 mm, the first metallized electrode 8 and the second metallized electrode 10 The capacitance formed between them tends to be small, and the sensitivity for detecting pressure tends to be low. Therefore, the distance between the first metallized electrode 8 and the second metallized electrode 10 is 0.
A range of 01 to 5 mm is preferred. Further, a frame portion 1d surrounding the ceramic plate 2 is formed on the outer peripheral portion of the upper surface of the ceramic base 1, and the protective plate 3 has a gap G between the frame portion 1d and the upper surface of the ceramic plate 2. And is joined so as to cover the upper surface of the ceramic plate 2. The frame portion 1d is a support portion for joining the protective plate 3 to the insulating substrate 1 so as to have a gap G between the protective plate 3 and the upper surface of the ceramic plate 2. The upper surface thereof has a metal such as tungsten, molybdenum, copper, silver or the like. A third bonding metallization layer 12 of powder metallization is applied. Then, the protection plate 3 is bonded to the ceramic base 1 by brazing the protection plate 3 to the third bonding metallization layer 12 via a brazing material such as silver-copper solder. Such a third bonding metallization layer 12
A metallized paste obtained by adding a suitable organic binder, a solvent, a plasticizer, and a dispersant to a metal powder such as tungsten is mixed and printed on a ceramic green sheet for the ceramic substrate 1 by using a conventionally known screen printing method. By firing this together with the green ceramic molded body for the ceramic base 1, a predetermined pattern is formed on the upper surface of the frame 1d of the ceramic base 1. The surface of the third bonding metallization layer 12 prevents the third bonding metallization layer 12 from being oxidized and corroded.
Normally, a nickel plating layer having a thickness of about 1 to 10 μm is applied to improve the bonding between 12 and the brazing material. A gap G is formed between the ceramic plate 2 and the upper surface.
The protection plate 3 joined to the insulating base 1 so as to cover the upper surface of the ceramic plate 2 is made of, for example, an iron-nickel-cobalt alloy or an iron-nickel alloy, and when the external pressure suddenly changes greatly, It functions as an impact buffering member for preventing the pressure and the impact of the foreign matter from being directly applied to the ceramic plate 2 when a foreign matter collides from the outside. At the center of the protection plate 3, a through hole 3a having a diameter of about 0.01 to 0.5 mm communicating with the gap G from the outside is formed. The protection plate 3 has such a through hole 3a. Accordingly, for example, even when the external pressure changes abruptly, the impact due to the change in the pressure is favorably mitigated by the air flowing into and out of the gap G through the through hole 3a. Further, even when foreign matter collides from the outside, the ceramic plate 2 is protected by the protective plate 3 and the foreign matter does not directly collide with the ceramic plate 2. It should be noted that such a protective plate 3 has a thickness of
When the thickness is less than 0.1 mm, there is a risk that the protection plate 3 may be destroyed by an impact generated when the external pressure changes drastically or when a foreign substance collides with the protection plate 3. If the thickness exceeds 5 mm, the thickness of the package is unnecessarily increased due to the provision of the protective plate 3 having such a thickness, and it is difficult to reduce the size of the pressure detecting device. Therefore, the thickness of the protection plate 3 is preferably in the range of 0.1 to 5 mm. The diameter of the through hole 3a is 0.01 mm.
If the pressure is less than the above, the amount of air flowing into and out of the gap G through the through hole 3a is small, and it takes time for the pressure in the gap G to become the same as the external pressure. If the response of the pressure detection becomes too slow, on the other hand, if it exceeds 0.5 mm, it becomes difficult to satisfactorily mitigate the impact due to the change of the external pressure, and foreign matter from the outside directly enters the ceramic plate 2 through the through hole 3a. The danger of collision increases. Therefore, the diameter of the through hole 3a is preferably in the range of 0.01 to 0.5 mm. Further, when the distance between the ceramic plate 2 and the protection plate 3 is less than 0.1 mm, when the external pressure changes drastically or when foreign matter collides with the protection plate 3, the protection plate 3 There is a risk that the contact with the ceramic plate 2 may hinder normal pressure detection. On the other hand, if it exceeds 5 mm, the thickness of the package becomes unnecessarily thick to provide such a gap and the pressure detection is performed. It becomes difficult to reduce the size of the device. Therefore, the distance between the ceramic plate 2 and the protection plate 3 is preferably in the range of 0.1 to 5 mm. As described above, according to the pressure detecting device package of the present invention, the other main surface of the ceramic base 1 on which the semiconductor element 4 is mounted on one main surface is provided with the first capacitance forming surface. One metallized electrode 8 is provided, and a closed space S is formed between the ceramic substrate 2 and the ceramic plate 2 having a second metallized electrode 10 for forming a capacitance facing the first metallized electrode 8 on the inner main surface. Since the bonding is performed in such a flexible state, the container accommodating the semiconductor element 4 and the pressure-sensitive element are integrated, and as a result, the pressure detection device can be downsized. Also, the first metallized electrode 8 and the second metallized electrode 10 for forming the capacitance are formed.
To the metallized wiring conductor 6a provided on the ceramic base 1.
6b, the first metallized electrode 8 and the second metallized electrode 10 can be connected to the semiconductor element 4 at a short distance, and as a result, these metallized wiring conductors 6a, 6b It is possible to provide a highly sensitive pressure detecting device with a small unnecessary capacitance generated therebetween. Further, the protective plate 3 covering the outer main surface of the ceramic plate 2 is provided so as to have a gap G between itself and the outer main surface of the ceramic plate 2 and to have a through hole 3a communicating with the gap G from outside. Therefore, even if the external pressure changes drastically or a foreign object collides, the impact of the pressure or the foreign object is greatly reduced by the protective plate 3, and as a result, cracks and cracks are generated in the ceramic plate. This can effectively prevent the airtightness of the sealed space S from being maintained, and provide a pressure detection device capable of accurately detecting the external pressure over a long period of time. Thus, according to the above-described package for a pressure detecting device, the semiconductor element 4 is mounted on the mounting portion 1b, and each electrode of the semiconductor element 4 and the metallized wiring conductor 6 are electrically connected. By sealing the element 4, a highly reliable pressure detection device that is small and has high sensitivity and can accurately detect an external pressure over a long period of time. The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the gist of the present invention. For example, in one example of the above-described embodiment, the ceramic base 1 and the ceramic plate 2 are joined by a brazing material. However, as shown in a cross-sectional view in FIG.
They may be joined by being sintered and integrated by simultaneous firing. In that case, it is not necessary to provide the first bonding metallization layer 9 and the second bonding metallization layer 11. In the above-described embodiment, the frame 1 surrounding the ceramic plate 2
d, and a flat protection plate 3 is provided on the frame portion 1d. However, without providing such a frame portion 1d, as shown in a sectional view of FIG. It may be bent toward the base 1 and processed into a bowl shape, which may be joined to the insulating base 1 so as to cover the ceramic plate 2. Alternatively, FIG.
As shown in the cross-sectional view, the protection plate 3 processed in such a bowl shape may be joined to the upper surface of the ceramic plate 2. In the embodiments shown in FIGS. 2 to 4, the same reference numerals as those used in FIG. 1 are used for parts substantially common to the embodiment shown in FIG. Is omitted. As described above, according to the package for a pressure detecting device of the present invention, a ceramic base having a mounting portion on which a semiconductor element is mounted on one main surface is provided on the other main surface. A first metallization electrode for forming a capacitance is provided, and a ceramic plate having a second metallization electrode for forming a capacitance, which is opposed to the first metallization electrode, on one main surface is formed on the other main surface of the ceramic base. The pressure sensitive element is integrated with the package accommodating the semiconductor element because the sealed space is formed between the pressure sensitive element and the flexible element. As a result, the pressure detecting device can be downsized. . In addition, since the first metallized electrode and the second metallized electrode for forming the capacitance are connected to the semiconductor element via the metallized wiring conductor provided on the insulating base, the first metallized electrode and the second metallized electrode can be short distance. As a result, an unnecessary capacitance generated between these metallized wiring conductors can be reduced to provide a highly sensitive pressure detecting device. Furthermore, since the protective plate that covers the outer main surface of the ceramic plate has a gap between the outer main surface of the ceramic plate and a through hole that communicates with the gap from the outside, external pressure is reduced. Even if there is a sudden large change or a foreign object collides, the pressure and the impact of the foreign object are greatly reduced by the protective plate, and as a result, cracks and cracks are effectively prevented from being generated on the ceramic plate. To provide a pressure detecting device capable of accurately detecting an external pressure over a long period of time by keeping airtightness of a sealed space formed between a ceramic substrate and a ceramic plate always good. Can be.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a cross-sectional view showing an example of an embodiment of a package for a pressure detecting device according to the present invention. FIG. 2 is a cross-sectional view showing another example of the embodiment of the pressure detection device package of the present invention. FIG. 3 is a cross-sectional view showing another example of the embodiment of the pressure detection device package of the present invention. FIG. 4 is a cross-sectional view showing another example of the embodiment of the pressure detection device package of the present invention. FIG. 5 is a sectional view showing a conventional pressure detecting device. [Description of Signs] 1 ... Ceramic base 1b ... Mounting section 2 ... Ceramic plate 3 ... Protective plate 3a ... Through hole 4 ... Semiconductor Element 6 Metallized wiring conductor 8 First metallized electrode 10 Second metallized electrode S Enclosed space G Gap

Claims (1)

Claims 1. A metallized wiring conductor having a plurality of metallized wiring conductors inside and on a surface thereof, a mounting portion on which a semiconductor element is mounted on one main surface, and one of the metallized wiring conductors on the other main surface. And a ceramic base having a first metallized electrode for forming a capacitance electrically connected to the ceramic base and the ceramic base in a flexible state so as to form a sealed space between the ceramic base and the other main surface. A ceramic plate having a second metallized electrode for forming a capacitance, which is opposed to the first metallized electrode on its inner main surface, and electrically connected to another one of the metallized wiring conductors; A protection plate that is disposed so as to cover the outer main surface of the ceramic plate with a gap between the outer main surface and the outer main surface, and that has a through-hole that partially has a through hole that communicates with the gap from outside. Specially Package for a pressure sensing device to.