JP2002039893A - Package for pressure detection apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a small, high-sensitivity pressure detection apparatus capable of accurately detecting external pressures over a long period of time. SOLUTION: In this package for the pressure detection apparatus, a first metallized electrode 7 for forming an electrostatic capacity is provided on one principal surface of a ceramic base 1 having a semiconductor device 3 mounted on the other principal surface thereof, and a ceramic plate 2 having on the inner principal surface thereof a second metallized electrode 9 opposed to the first metallized electrode 7 for forming an electrostatic capacity, and also having a reinforcing metallized layer 10 on the outer principal surface thereof, is flexibly joined with the ceramic base 1 in such a way as to form a closed space therebetween.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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.

[0002]

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. 4, 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 accommodated 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 with
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 is composed of 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 in response to an external pressure. The capacitance formed between the forming electrodes 23 and 25 changes. Then, an external pressure can be detected by arithmetically processing the change in the capacitance by the semiconductor element 29 for arithmetic operation.

[0003]

However, according to the 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 detecting device and the pressure detecting 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 base having a mounting portion on one main surface on which a semiconductor element is mounted; and a plurality of wiring conductors disposed on and inside the insulating base and electrically connected to respective electrodes of the semiconductor element. A first electrode for forming a capacitance, which is attached to the center 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, which is attached to face the first electrode and faces the first electrode. A pressure detection device package including a second electrode for forming a capacitance electrically connected to another one has been proposed. According to this 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 is Since the insulating plate having the opposing second electrode for capacitance formation on the inner surface is joined in a flexible state so as to form a sealed space with the other main surface of the insulating base, The pressure-sensitive element is formed integrally with the package containing the semiconductor element, and as a result, the pressure detection device can be reduced in size, and the wiring for 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 pressure detecting device package proposed in Japanese Patent Application No. 2000-178618, the insulating plate is made of a brittle ceramic material, so that when an external pressure is repeatedly applied to the insulating plate, the insulating plate becomes insulated. Small cracks are generated on the outer peripheral edge of the plate, gradually progressing to the center of the insulating plate, and finally the airtightness of the sealed space between the insulating base and the insulating plate is reduced, so that the external pressure May not be able to be detected accurately.

The present invention has been completed in view of the above-mentioned problems, and an object of the present invention is 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.

[0007]

A package for a pressure detecting device according to the present invention is provided on a ceramic substrate having a mounting portion on one side of which a semiconductor element is mounted, and disposed on and inside the ceramic substrate. A plurality of metallized wiring conductors to which each electrode of the semiconductor element is electrically connected; and a capacitance applied to the center of the other main surface of the ceramic base and electrically connected to one of the metallized wiring conductors. A first metallized electrode for formation, and on the other main surface of the ceramic substrate,
A ceramic plate joined in a flexible state so as to form a sealed space with the central portion of the main surface; and a metallized plate attached to the inner main surface of the ceramic plate so as to face the first metallized electrode. A package for a pressure detecting device comprising: a second metallized electrode for forming a capacitance electrically connected to another one of the wiring conductors, wherein the ceramic plate is reinforced over substantially the entire outer main surface thereof A metallized layer for use.

According to the pressure detecting device package of the present invention, the first metallized electrode for forming the capacitance is provided on the other main surface of the ceramic base having the mounting portion on which the semiconductor element is mounted on one main surface. In addition, the ceramic plate having an inner surface on which a second metallized electrode for forming a capacitance facing the first metallized electrode is formed so as to form a closed space between the ceramic plate and the other main surface of the ceramic substrate. The pressure sensitive element is formed integrally with the package that contains the semiconductor element, and as a result, the pressure detection device can be made smaller and the pressure detecting electrode and the semiconductor element are connected. By reducing the length of the wiring, unnecessary capacitance generated between these wirings can be reduced. Furthermore, since a metallization layer for reinforcement was applied to almost the entire outer main surface of the ceramic plate,
When external pressure is repeatedly applied to the ceramic plate,
Cracks are effectively prevented from occurring in the outer peripheral portion of the ceramic plate, and even if cracks are generated, the crack is effectively prevented from progressing to the center of the ceramic plate.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 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 pressure detection device package according to the present invention.
1 is a ceramic base, 2 is a ceramic plate, 3 is a semiconductor element.

The ceramic substrate 1 is made of a ceramic material such as a sintered body of aluminum oxide, a sintered body of aluminum nitride, a sintered body of mullite, a sintered body of silicon carbide, a sintered body of silicon nitride, or a glass-ceramic. A laminate comprising
For example, in the case 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, solvent, plasticizer, and dispersant to form a slurry, which is formed into a sheet by employing a conventionally known doctor blade method. A plurality of ceramic green sheets were obtained, and thereafter, these ceramic green sheets were subjected to appropriate punching, laminating, and cutting to obtain a green ceramic molded body for the insulating substrate 1 and to reduce the green ceramic molded body to approximately one. It is manufactured by firing at a temperature of 1600 ° C.

The ceramic base 1 has a concave portion 1a for accommodating the semiconductor element 3 in the center of the lower surface thereof, and thereby functions as a container for accommodating the semiconductor element 3. The center of the bottom surface of the concave portion 1a is a mounting portion 1b on which the semiconductor element 3 is mounted.
The semiconductor element 3 is sealed by mounting the semiconductor element 3 on the substrate b and filling the recess 1a with a resin sealing material 4 such as an epoxy resin. In this example, the semiconductor element 3 is sealed by filling a resin sealing material 4 into the recess 1a, but the semiconductor element 3 is provided with a lid made of metal or ceramic on the lower surface of the ceramic base 1 in the recess 1a. It may be sealed by joining so as to close.

A plurality of metallized wiring conductors 5 connected to the respective electrodes of the semiconductor element 3 are led out from the mounting portion 1b. The metallized wiring conductor 5 and the respective electrodes of the semiconductor element 3 are connected to the solder bumps 6 and the like. By bonding via a conductive bonding member made of a conductive material, each electrode of the semiconductor element 3 is electrically connected to each metallized wiring conductor 5, and the semiconductor element 3 is fixed to the mounting portion 1b. In this example, the electrodes of the semiconductor element 3 and the metallized wiring conductors 5 are connected via the solder bumps 6, but the electrodes of the semiconductor element 3 and the metallized wiring conductors 5 are connected to another type of electric wire such as a bonding wire. May be connected by a dynamic connection means.

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. 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 7 and the second metallized electrode 9. Then, each electrode of the semiconductor element 3 is electrically connected to the metallized wiring conductor 5 via a conductive bonding material 6 and the semiconductor element 3 is sealed with a resin sealing material 4. The semiconductor element 3 housed inside is electrically connected to the external electric circuit by joining the portion led out to the lower surface of the outer periphery of the ceramic base 1 to the wiring conductor of the external electric circuit board via a conductive bonding material such as solder. Will be done.

Such a metallized wiring conductor 5 is made of metallized metal powder such as tungsten, molybdenum, copper, silver or the like. The metallized paste thus obtained is applied in a predetermined pattern to a ceramic green sheet for the ceramic substrate 1 by employing a conventionally 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. In addition, in order to prevent the metallized wiring conductor 5 from being oxidized and corroded and to make the metallized wiring conductor 5 and a conductive bonding material such as solder good, the exposed surface of the metallized wiring conductor 5 is usually formed on the exposed surface. 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 frame-shaped projection 1c having a height of about 0.01 to 5 mm is provided on the outer peripheral portion of the upper surface of the ceramic base 1, whereby a concave portion 1 having a substantially flat bottom surface is provided at the center of the upper surface.
d is formed. The concave portion 1d is for forming a closed space between the concave portion 1d and the ceramic plate 2, and a first metallized electrode 7 for forming a capacitance is attached to the bottom surface of the concave portion 1d. ing.

The first metallized electrode 7 is for forming a capacitance for a pressure-sensitive element together with a second metallized electrode 9 described later, and is formed, for example, in a substantially circular pattern. One of the metallized wiring conductors 5a is connected to the first metallized electrode 7 so that 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.

The first metallized electrode 7 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 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. A predetermined pattern is formed on the bottom surface of 1d. In addition, in order to prevent the first metallized electrode 7 from being oxidized and corroded, the exposed surface of the first metallized electrode 7 is usually
A nickel plating layer having a thickness of about 1 to 10 μm is applied.

On the upper surface of the projection 1c of the ceramic base 1, a frame-shaped joining metallization layer 8 is attached over the entire periphery thereof. The second metallized electrode 9 and the bonding metallized layer 8 are formed of silver-
It is attached by joining via a conductive joining material such as a copper brazing material.

One of the metallized wiring conductors 5b is connected to the bonding metallized layer 8 so that the electrodes of the semiconductor element 3 are connected to the metallized wiring conductor 5b via a conductive bonding material such as a solder bump 6. When electrically connected to each other, the second metallized electrode 9 connected to the bonding metallized layer 8 and the electrode of the semiconductor element 3 are electrically connected.

The bonding metallization layer 8 is made of a metal powder metallization such as tungsten, molybdenum, copper, silver or the like.
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 with a ceramic green sheet for the ceramic substrate 1 by printing using a conventionally known screen printing method. By firing this together with the green ceramic molded body for the ceramic base 1, a predetermined frame-like pattern is formed on the upper surface of the projection 1c of the ceramic base 1. The exposed surface of the bonding metallization layer 8 is provided on the exposed surface of the bonding metallization layer 8.
A nickel plating layer having a thickness of about 1 to 10 μm is usually applied to prevent oxidation corrosion of the metal and to strengthen the bonding between the bonding metallized layer 8 and the conductive bonding material. ing.

The ceramic plate 2 attached to the upper surface of the ceramic base 1 is made of a sintered body of aluminum oxide, sintered body of aluminum nitride, sintered body of mullite, sintered body of silicon nitride, sintered body of silicon carbide. A substantially flat plate made of a ceramic material such as a sintered body or glass-ceramic and having a thickness of 0.01 to 5 mm, and functions as a so-called pressure detecting diaphragm that bends toward the ceramic base 1 in response to external pressure.

The ceramic plate 2 has a thickness of 0.01.
If it is less than 5 mm, its mechanical strength will be small, so that when a large external pressure is applied thereto, there is a great risk of being destroyed.
If it exceeds m, it becomes difficult to bend under a small pressure, and it is 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.

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 a 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. .

Further, a second metallized electrode 9 for forming a capacitance is attached to substantially the entire lower surface of the ceramic plate 2. The second metallized electrode 9 functions as an electrode for forming a capacitance for a pressure-sensitive element together with the first metallized electrode 7 described above, and also serves as a bonding base metal for bonding the ceramic plate 2 to the ceramic base 1. Functions as a layer.

The second metallized electrode 9 is made of metal powder of metal 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 plate 2 by employing a conventionally well-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 over substantially the entire surface of the substrate. The exposed surface of the second metallized electrode 9 is prevented from being oxidized and corroded by the second metallized electrode 9.
Usually, a nickel plating layer having a thickness of about 1 to 10 μm is applied in order to improve the bonding between the metal and the conductive bonding material.

The second metallized electrode 9 and the metallized layer 8 for bonding are bonded via a conductive bonding material such as a silver-copper brazing material, so that the upper surface of the ceramic base 1 and the lower surface of the ceramic plate 2 are connected. A sealed space is formed therebetween, and the bonding metallized layer 8 and the second metallized electrode 9 are electrically connected.

At this time, the first metallized electrode 7 and the second metallized electrode 9 face each other with a space formed between the ceramic base 1 and the ceramic plate 2 therebetween. A predetermined capacitance is formed according to the area of one metallized 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 bends toward the ceramic base 1 according to the pressure, and the distance between the first metallized electrode 7 and the second metallized electrode 9 changes, 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 of the capacitance is transmitted to the semiconductor element 3 housed in the recess 1a via the metallized wiring conductors 5a and 5b, and the magnitude of the external pressure is known by performing arithmetic processing on the semiconductor element 3. be able to.

As described above, according to the pressure detecting device package of the present invention, the first metallization for forming the capacitance is provided on the other main surface of the ceramic base 1 on which the semiconductor element 3 is mounted on one main surface. An electrode 7 is provided, and a ceramic plate 2 having a second metallized electrode 9 for forming a capacitance facing the first metallized electrode 7 on an inner main surface is formed so as to form a closed space between the ceramic plate 2 and the ceramic substrate 1. Since they are joined in a flexible state, the container for accommodating the semiconductor element 3 and the pressure-sensitive element are integrated, and as a result, the size of the pressure detection device can be reduced. Since the first metallized electrode 7 and the second metallized electrode 9 for forming the capacitance are connected to the semiconductor element 3 via the metallized wiring conductors 5a and 5b provided on the ceramic base 1, the first metallized electrode 7 And the second metallized electrode 9 can be connected to the semiconductor element 3 at a short distance, and as a result, unnecessary capacitance generated between these metallized wiring conductors 5a and 5b is reduced, and a highly sensitive pressure detecting device is provided. Can be provided.

When the distance between the first metallized electrode 7 and the second metallized electrode 9 is less than 0.01 mm at 1 atm, when a large pressure is applied to the ceramic plate 2,
There is a danger that the first metallized electrode 7 and the second metallized electrode 9 may come into contact with each other and the pressure cannot be detected. 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 7 and the second metallized electrode 9 is 0.
A range from 01 to 5 mm is preferred.

On the upper surface of the ceramic plate 2, a metallization layer 10 for reinforcement is applied over substantially the entire surface. The reinforcing metallization layer 10 is made of metal powder of metal such as tungsten, molybdenum, copper, silver, or the like. It functions as a barrier for preventing the crack from advancing to the center of the ceramic plate 2 even if the crack occurs. As described above, according to the pressure detecting device package of the present invention, since the reinforcing metallization layer 10 is applied to substantially the entire outer main surface of the ceramic plate 2, external pressure is repeatedly applied to the ceramic plate 2. Even when the voltage is applied, cracks are effectively prevented from being generated on the outer peripheral portion of the ceramic plate 2, and even if cracks are generated, the cracks can propagate to the central portion of the ceramic plate 2. It is effectively prevented, and as a result, the airtightness of the sealed space formed between the ceramic base 1 and the ceramic plate 2 does not decrease, and therefore, it is possible to accurately detect the external pressure for a long period of time. is there.

When the thickness of the reinforcing metallized layer 10 is less than 5 μm, when an external pressure is repeatedly applied to the ceramic plate 2, cracks are generated on the outer peripheral portion of the ceramic plate 2 and the cracks are generated. When it exceeds 50 μm, the risk of not being able to effectively prevent the metal from proceeding to the center of the ceramic plate 2 is increased.
Due to the difference in thermal expansion coefficient between the ceramic plate 2 and the reinforcing metallized layer 10, the risk of the reinforcing metallized layer 10 peeling off from the ceramic plate 2 increases. Therefore, the thickness of the reinforcing metallized layer 10 is preferably in the range of 5 to 50 μm.

The metallized paste 10 obtained by adding a suitable organic binder, solvent, plasticizer and dispersant to a metal powder such as tungsten and mixing the metallized paste with a conventionally well-known screen printing method is used for the metallized layer 10 for reinforcement. Ceramic plate 2
The ceramic green sheet is printed and applied, and is fired together with the green ceramic molded body for the ceramic plate 2 to form a predetermined pattern on substantially the entire upper surface of the ceramic plate 2. On the exposed surface of the metallizing layer 10 for reinforcement, in order to prevent the metallizing layer 10 for reinforcement from being oxidized and corroded, a nickel plating layer having a thickness of about 1 to 10 μm and a thickness of 0.1 to 3 μm are usually used. A gold plating layer is applied.

Thus, according to the above-described package for a pressure detecting device, the semiconductor element 3 is mounted on the mounting portion 1b, and each electrode of the semiconductor element 3 is electrically connected to the metallized wiring conductor 5. By sealing the element 3, a highly reliable pressure detection device which is small in size, has high sensitivity, and is capable of accurately detecting 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 an example of the above-described embodiment, a frame-shaped protrusion 1c is provided on the outer peripheral portion of the upper surface of the ceramic base 1, and the ceramic plate 2 is joined onto the protrusion 1c, so that the upper surface of the ceramic base 1 and the ceramic plate 2 I tried to provide a closed space between
According to the present invention, as shown in the sectional view of FIG. 2, a frame-shaped projection 2a is provided on the outer peripheral portion of the lower surface of the ceramic plate 2 and this is joined to the upper surface of the ceramic substrate 1.
A closed space may be provided between the ceramic plate 2 and the ceramic plate 2. In this case, a metallization layer 11 for bonding may be provided on the lower surface of the protrusion 2a, and the metallization layer 11 for bonding may be bonded to the metallization layer 8 for bonding via a conductive bonding material such as silver-copper solder. The bonding metallization layer 11 and the second metallization electrode 9 may be electrically connected by providing the metallization conductor 12 for connection to the ceramic plate 2 to connect them.

Further, according to the present invention, as shown in the sectional view of FIG. 3, a metal frame 13 made of, for example, an iron-nickel-cobalt alloy or an iron-nickel alloy is provided on the outer peripheral portion of the upper surface of the ceramic base 1 by using a silver-copper solder. The ceramic base 2 and the ceramic plate 2 are joined together by bonding the ceramic plate 2 on the metal frame 13 via a conductive joining material such as silver-copper solder. A closed space may be provided between them.

[0036]

As described above, according to the pressure detecting device package of the present invention, the capacitance is provided on the other main surface of the ceramic base having the mounting portion on which the semiconductor element is mounted on one main surface. A first metallized electrode for formation is provided, and a ceramic plate having a second metallized electrode for capacitance formation facing the first metallized electrode on the inner surface is hermetically sealed with the other main surface of the ceramic base. Since the space is formed and joined in a flexible state, the pressure-sensitive element is integrated with the package accommodating the semiconductor element, and as a result, the pressure detection 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 distances. As a result, it is possible to provide a pressure sensitive device with high sensitivity by reducing unnecessary capacitance generated between these metallized wiring conductors. Furthermore, since a metallizing layer for reinforcement is applied to almost the entire outer main surface of the ceramic plate, even when external pressure is repeatedly applied to the ceramic plate, cracks are formed on the outer peripheral portion of the ceramic plate. This can be effectively prevented from occurring, and even if a crack occurs, the crack is effectively prevented from progressing to the center of the ceramic plate, and as a result, between the ceramic substrate and the ceramic plate. The airtightness of the formed closed space is not reduced, and therefore, the external pressure can be accurately detected over a long period of time.

[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 according to the present invention.

FIG. 3 is a cross-sectional view showing still another example of the embodiment of the pressure detecting device package according to the present invention.

FIG. 4 is a sectional view showing a conventional pressure detecting device.

[Explanation of symbols]

 1 Ceramic substrate 2 Ceramic plate 3 Semiconductor element 5, 5a, 5b Metallized wiring conductor 7 First metallized electrode 9 ... Second metallized electrode 10 ... Reinforcing metallized layer

Claims (1)

[Claims] 1. A ceramic base having a mounting portion on one side of which a semiconductor element is mounted, and a plurality of ceramic bases disposed on and inside the ceramic base and electrically connected to respective electrodes of the semiconductor element. A metallized wiring conductor; a first metallized electrode for forming a capacitance, which is attached to a center portion of the other main surface of the ceramic base and is electrically connected to one of the metallized wiring conductors; A ceramic plate joined in a flexible state so as to form a closed space between the ceramic plate and the central portion; and an inner main surface of the ceramic plate adhered to the first metallized electrode in opposition to the first metallized electrode. And a second metallized electrode for forming a capacitance electrically connected to another one of the metallized wiring conductors, wherein the ceramic plate has an outer main surface. Almost all over A package for a pressure detecting device, wherein a metallizing layer for reinforcement is adhered to the package.