JP2005077134A - Package for pressure detector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a package for a pressure detector of a small size and high sensitivity capable of detecting accurately external pressure. <P>SOLUTION: This package for the pressure detector is provided with an insulation base 1 having a mounting part 1b for mounting a semiconductor element 4 on its one main face, a plurality of wiring conductors 6 arranged on a surface and in an inside of the insulation base 1, and connected electrically to respective electrodes of the semiconductor element 4, the first insulation plate 2 joined to the other main face of the insulation base 1, the second insulation plate 3 joined flexibly to an outer circumferential part of the first insulation plate 2 to form a sealed space with respect to the first insulation plate 2 therebetween, the first electrode 8 attached to the main face of the first insulation plate 2 inside the sealed space, and for forming an electrostatic capacity connected electrically to one 6a of the wiring conductors, and the second electrode 9 attached to the main face of the second insulation plate 3 inside the sealed space, and for forming an electrostatic capacity connected electrically to another one 6b of the wiring conductors. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a package for a pressure detection device used in a pressure detection device for detecting pressure.

  Conventionally, a capacitance type pressure detection device is known as a pressure detection device for detecting pressure. As shown in a cross-sectional view in FIG. 4, this capacitance type pressure detection device is accommodated in a capacitance type pressure sensitive element 32 and a package 38 on a wiring board 31 made of a ceramic material or a resin material. And a semiconductor element 39 for calculation.

  The pressure sensitive element 32 is made of, for example, an electrically insulating material such as a ceramic material, and has an insulating base 34 having a concave portion in which one electrode 33 for forming a capacitance is attached at the center of the upper surface, and the insulating base 34. An insulating plate 36 which is joined in a flexible state so as to form a sealed space between the upper surface of the substrate and the insulating base 34 and the other electrode 35 for forming a capacitance is attached to the lower surface, and each static plate. Each of the capacitance forming electrodes 33 and 35 is composed of an external lead terminal 37 for electrically connecting to the outside, and each capacitance is formed by bending the insulating plate 36 according to the external pressure. The capacitance formed between the electrodes 33 and 35 for use changes. An external pressure can be detected by performing arithmetic processing on the change of the electrostatic capacitance by the semiconductor element 39 for arithmetic operation.

  However, according to this conventional pressure detection device, since the pressure sensitive element 32 and the semiconductor element 39 are individually mounted on the wiring substrate 31, the pressure detection device is increased in size and the pressure detection electrode 33 is provided. , 35 and the semiconductor element 39 are long, and unnecessary capacitance is formed between the long wires, so that the sensitivity is low.

  In view of this, the applicant of the present application disclosed in Patent Document 1 an insulating base 21 having a mounting portion 21b on one main surface on which a semiconductor element 23 is mounted, as shown in a cross-sectional view in FIG. And a plurality of wiring conductors 25 disposed inside and electrically connected to each electrode of the semiconductor element 23, and attached to the central portion of the other main surface of the insulating base 21. In a flexible state so as to form a sealed space between the electrically connected first electrode 27 for forming capacitance and the other main surface of the insulating base 21 with the central portion of the main surface. A bonded insulating plate 22 and an inner main surface of the insulating plate 22 are attached to face the first electrode 27 and are electrically connected to the other one of the wiring conductors 25 for forming a capacitance. A package for a pressure detection device including the second electrode 29 was proposed.

  According to this pressure detection device package, the first electrode 27 for forming a capacitance is provided on the other main surface of the insulating base 21 having the mounting portion 21b on which the semiconductor element 23 is mounted on one main surface, The insulating plate 22 having the second electrode 29 for forming a capacitance facing the first electrode 27 on the inner surface is flexible so as to form a sealed space between the other main surface of the insulating base 21. Since the pressure sensitive element is integrally formed in the package that accommodates the semiconductor element 23, the pressure detecting device can be reduced in size and the pressure detecting electrode, the semiconductor element 23, It is possible to reduce the unnecessary electrostatic capacitance generated between these wirings by shortening the wiring for connecting the wires.

  Conventionally, the first electrode 27 of these packages is made of metal powder metallization such as tungsten, molybdenum, copper, and silver, and an appropriate organic binder, solvent, plasticizer, and dispersant are 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 insulating substrate 21 (hereinafter also simply referred to as a green sheet) using a conventionally known screen printing method, and this is fired together with the green ceramic molded body for the insulating substrate 21. As a result, a predetermined pattern is formed at the center of the upper surface of the insulating base 21.

  The second electrode 29 is made of metal powder metallization such as tungsten, molybdenum, copper, silver, etc., and is obtained by adding and mixing an appropriate organic binder, solvent, plasticizer, and dispersant to metal powder such as tungsten. Is applied to a ceramic green sheet for the insulating plate 22 (hereinafter also referred to as a green sheet) by employing a well-known screen printing method, and this is fired together with a green ceramic molded body for the insulating plate 22. 22 predetermined patterns are formed.

  Further, in order to use the first electrode 27 and the second electrode 29 for forming a capacitance, it is necessary to form a certain region between the first electrode 27 and the second electrode 29. 21 or the outer peripheral portion of the insulating plate 22 is formed with a frame-shaped projection 22b and a recess 22a is formed, thereby forming a sealed space for forming a capacitance between the insulating base 21 and the insulating plate 22. It was.

In addition, the insulating base 21 and the insulating plate 22 are formed with a first bonding metallized layer 28 and a second bonding metallized layer 30 on the outer peripheral portion or the frame-shaped protrusion 22b. And the second bonding metallization layer 30 were bonded by a brazing material or the like.
Japanese Patent Laid-Open No. 2001-356064

  However, in the conventional package for a pressure detection device, since the first electrode 27 and the second electrode 29 are formed by a screen printing method, the surface has a high flatness, It is difficult to make the distance between the second electrode 29 uniform, the capacitance generated between the first electrode 27 and the second electrode 29 varies, and the sensitivity tends to decrease. Had.

  In addition, since the insulating base 21 has a large number of wiring conductors 25 formed therein, when fired, the main surface of the insulating base 21 is uneven due to a difference in shrinkage between the ceramic green sheet and the conductive paste. Therefore, when the insulating plate 22 is joined to the insulating base 21, the insulating base 21 and the insulating plate 22 are inclined and joined, and the external pressure fluctuates to cause the insulating plate 22 to change. When it bends, the variation in capacitance occurs, which makes it difficult to accurately detect the external pressure.

  Therefore, it is required to improve the flatness by polishing the other main surface of the insulating base 21. However, since the insulating base 21 has the concave portions 21a, the convex portions, etc., it takes time to process. At the same time, since the other main surface of the insulating base 21 is uneven, there is a problem that the time and sensitivity of the insulating base 21 are likely to vary in each polishing process.

  Accordingly, the present invention has been devised in view of such conventional problems, and an object of the present invention is to provide a package for a pressure detection device that is small in size, has high sensitivity for detecting external pressure, and can be easily manufactured. is there.

  The package for a pressure detection device according to the present invention includes an insulating base having a mounting portion on which a semiconductor element is mounted on one main surface, and a surface and an inside of the insulating base, and each electrode of the semiconductor element is electrically A plurality of wiring conductors connected to the first insulating plate, a first insulating plate joined to the other main surface of the insulating base, and the first insulating plate so as to form a sealed space between the first insulating plate and the first insulating plate. A second insulating plate joined in a flexible state to the outer periphery of the first insulating plate, and a static insulation member attached to the main surface of the first insulating plate in the sealed space and electrically connected to one of the wiring conductors. A first electrode for forming a capacitance and a first electrode for forming a capacitance that is attached to the main surface of the second insulating plate in the sealed space and is electrically connected to the other one of the wiring conductors. And two electrodes.

  According to the package for a pressure detection device of the present invention, an insulating base having a mounting portion on which a semiconductor element is mounted on one main surface, and the surface of and inside the insulating base, each electrode of the semiconductor element is electrically connected. A plurality of wiring conductors connected to each other, a first insulating plate joined to the other main surface of the insulating base, and a first insulating plate so as to form a sealed space between the first insulating plate and the first insulating plate. For forming a capacitance that is attached to the main surface of the second insulating plate that is flexibly joined to the outer periphery and the first insulating plate in the sealed space and is electrically connected to one of the wiring conductors. And a second electrode for forming a capacitance that is attached to the main surface of the second insulating plate in the sealed space and is electrically connected to the other one of the wiring conductors. Therefore, since the first insulating plate and the second insulating plate are made of flat plates, the surface unevenness can be easily reduced and the first Since the surface of the edge plate and the second insulating plate can be easily processed such as polishing, the surfaces of the first insulating plate and the second insulating plate can be easily and flattened. The electrodes are easily formed flat on the upper surfaces of the first insulating plate and the second insulating plate, respectively, and the first insulating plate and the second insulating plate are easily joined in parallel. Since it becomes easy to form in a parallel state, when the external pressure fluctuates, it will be uniformly shifted with respect to the center of the first electrode and the second electrode, and is detected by the first electrode and the second electrode. Variations in capacitance can be reduced, and external pressure can be detected with high accuracy.

  In addition, since both the surface of the first insulating plate and the surface of the second insulating plate can be made excellent in smoothness, an extremely thin metal thin film, solder, etc. can be used to cope with these thicknesses. It is possible to form a sealed space with a small gap between the first insulating plate and the second insulating plate with high accuracy, and the first and second electrodes are opposed to each other as in the conventional case for sealing the capacitance. When forming the space, it is not necessary to form a relatively large frame-shaped projection, and the first and second electrodes for obtaining a predetermined capacitance can be made smaller, and the first insulation Since the plate for the pressure detection device can be made small by reducing the plate and the second insulating plate, and the mass of the second insulating plate and the second electrode can be reduced, the second insulation by centrifugal acceleration Minimizes the influence of bending of the plate The and it is possible to, it becomes the external pressure can be accurately detected.

  In addition, even if unevenness or warpage occurs on one main surface of the insulating substrate, the capacitance formed between the first insulating plate and the second insulating plate bonded to one main surface of the insulating substrate Therefore, it is possible to accurately detect the external pressure.

  Next, the pressure detection device package of 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 detecting device package according to the present invention. In FIG. 1, 1 is an insulating substrate, 2 is a first insulating plate, 3 is a second insulating plate, A semiconductor element, 8 is a first electrode, and 9 is a second electrode.

  The insulating substrate 1 is a laminate made of an electrically insulating 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, or a glass-ceramic. For example, in the case of an aluminum oxide sintered body, an appropriate organic binder, solvent, plasticizer, and dispersant are added to and mixed with ceramic raw material powder such as aluminum oxide, silicon oxide, magnesium oxide, and calcium oxide. As a result, a plurality of ceramic green sheets are obtained by forming this into a sheet shape by adopting a conventionally well-known doctor blade method, and then appropriately punching these ceramic green sheets. A green ceramic molded body for the insulating substrate 1 is obtained by laminating and cutting, and the green ceramic molded body is obtained. It is manufactured by firing at a temperature of about 1600 ° C..

  The insulating base 1 has a concave portion 1a for accommodating the semiconductor element 4 formed on one main surface (lower surface in FIG. 1), thereby functioning as a container for accommodating the semiconductor element 4. The central portion of the bottom surface of the recess 1a is a mounting portion 1b on which the semiconductor element 4 is mounted. The semiconductor element 4 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 4 is sealed by filling the material 5 and covering the semiconductor element 4.

  In this example, the semiconductor element 4 is sealed by covering the semiconductor element 4 with a resin sealing material 5. The semiconductor element 4 has a lid made of metal or ceramics on one main surface of the insulating base 1. You may seal by making it join so that the recessed part 1a may be plugged up.

  A plurality of wiring conductors 6 connected to the respective electrodes of the semiconductor element 4 are led out to the mounting portion 1b. The wiring conductor 6 and the respective electrodes of the semiconductor element 4 are electrically conductive made of a conductive material such as a solder bump. The electrodes of the semiconductor element 4 and the wiring conductors 6 are electrically connected to each other through the bonding material 7 and the semiconductor element 4 is fixed to the mounting portion 1b. In this example, the electrode of the semiconductor element 4 and the wiring conductor 6 are connected via solder bumps, but the electrode of the semiconductor element 4 and the wiring conductor 6 are connected to other electrical connection means such as bonding wires. May be connected.

  The wiring conductor 6 functions as a conductive path for electrically connecting each electrode of the semiconductor element 4 to the external electric circuit and the first electrode 8 and the second electrode 9, and a part of the wiring conductor 6 is one main part of the insulating substrate 1. It is led out to the outer periphery of the surface, and another part is electrically connected to the first electrode 8 and the second electrode 9. Each electrode of the semiconductor element 4 is electrically connected to these wiring conductors 6 through a conductive bonding material 7 such as a solder bump, and the semiconductor element 4 is sealed with a resin sealing material 5. The portion led out to the outer peripheral portion of one main surface of the insulating base 1 of the conductor 6 is accommodated in the interior by joining a conductive conductor 7 such as solder to a wiring conductor (not shown) of the external electric circuit board. The semiconductor element 4 to be connected is electrically connected to the external electric circuit.

  Such a wiring conductor 6 is made of metal powder metallization such as tungsten, molybdenum, copper, and silver, and is obtained by adding and mixing an appropriate organic binder, solvent, plasticizer, dispersant, etc. to metal powder such as tungsten. The paste is applied in a predetermined pattern to a ceramic green sheet for the insulating substrate 1 by using a conventionally known screen printing method, and this is fired together with a green ceramic molded body for the insulating substrate 1 to synthesize the inside of the insulating substrate 1. In addition, a predetermined pattern is formed on the surface. The exposed surface of the wiring conductor 6 has a thickness of 1 in order to prevent the wiring conductor 6 from being oxidatively corroded and to improve the bonding between the wiring conductor 6 and the conductive bonding material 7 such as solder. It is preferable that a nickel plating layer having a thickness of about ˜10 μm and a gold plating layer having a thickness of about 0.1 to 3 μm are sequentially deposited.

  A central portion of the other main surface (upper surface in FIG. 1) of the insulating base 1 is electrically connected to a wiring conductor 6a which is one of the wiring conductors 6, and a first insulating plate 2 which will be described later. The first bonding layer 10a serving as a conductive path to the first electrode 8 and the bonding portion of the wiring conductor 6 is formed around the first bonding layer 10a. In addition, a second bonding layer 10b is formed which is connected to the first insulating plate 2 described later and serves as a conductive path to the second electrode 9.

  The first bonding layer 10a and the second bonding layer 10b are made of metal powder metallization such as tungsten, molybdenum, copper, silver, and the like, and organic binders, solvents, plasticizers, dispersants, and the like suitable for metal powders such as tungsten. The metallized paste obtained by adding and mixing is printed on a ceramic green sheet for the insulating substrate 1 in a predetermined pattern using a conventionally known screen printing method, and this is fired together with the green ceramic molded body for the insulating substrate 1. By doing so, a predetermined pattern is formed on the other main surface of the insulating substrate 1. The exposed surfaces of the first bonding layer 10a and the second bonding layer 10b prevent the first bonding layer 10a and the second bonding layer 10b from being oxidized and corroded, and the first bonding layer 10a and the second bonding layer 10b. It is preferable that a nickel plating layer having a thickness of about 1 to 10 μm is applied in order to achieve good bonding between the solder and the conductive bonding material 7 such as solder.

  The first insulating plate 2 is bonded to the other main surface (the upper surface in FIG. 1) of the insulating base 1. The first insulating plate 2 has a flat plate shape made of a ceramic material such as an aluminum oxide sintered body, an aluminum nitride sintered body, a mullite sintered body, or glass-ceramics. For example, when the first insulating plate 2 is made of an aluminum oxide sintered body, an organic binder, a solvent, a plastic suitable for ceramic raw material powders such as aluminum oxide, silicon oxide, magnesium oxide, and calcium oxide are used. Add and mix the agent and dispersant to make a slurry, and then form this into a sheet using the well-known doctor blade method to obtain a plurality of ceramic green sheets. The green ceramic molded body for the first insulating plate 2 is obtained by subjecting the sheet to appropriate punching, laminating, and cutting, and the green ceramic molded body is manufactured by firing at a temperature of about 1600 ° C.

  A first electrode 8 for forming a capacitance is attached to the center of the upper surface of the first insulating plate 2. The first electrode 8 is for forming a capacitance for a pressure sensitive element together with a second electrode 9 described later, and is formed in, for example, a circular pattern.

  The first electrode 8 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, and dispersant to metal powder such as tungsten. The paste is printed and applied to a ceramic green sheet for the first insulating plate 2 by employing a conventionally known screen printing method, and is fired to form a predetermined pattern on the upper surface of the first insulating plate 2. 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 on the surface of the first electrode 8 to prevent the first electrode 8 from being oxidized and corroded. Preferably it is.

  Since the upper surface of the first insulating plate 2 or the surface of the first electrode 8 is preferably flat, the surface of the first electrode 8 may be flattened by polishing or the like, for example, tungsten or the like. After the surface of the first electrode 8 made of is flattened, a plating layer such as a nickel plating layer or a gold plating layer is preferably applied.

  Further, around the first electrode 8, a first metal that serves as a joint for joining the second insulating plate 3 to the upper surface of the first insulating plate 2 and serves as a conductive path to the second electrode 9 described later. Layer 11 is formed.

  Such a first metal layer 11 is formed in the same manner as the first electrode 8 and is made of metal powder metallization such as tungsten, molybdenum, copper, silver, etc., and an appropriate organic binder, solvent, A metallized paste obtained by adding and mixing a plasticizer and a dispersant is applied to a ceramic green sheet for the first insulating plate 2 by using a conventionally known screen printing method, and then fired. 2 is formed in a predetermined frame-like pattern on the upper surface. Further, the surface of the first metal layer 11 is nickel-plated with a thickness of about 1 to 10 μm to prevent the first metal layer 11 from being oxidatively corroded and to strengthen the bonding with the second insulating plate 3. It is preferable that the layer and the gold plating layer having a thickness of about 0.1 to 3 μm are sequentially deposited.

  In addition, since the surface of the first metal layer 11 is preferably in a flat state like the first electrode 8 in order to join the second insulating plate 3 in a parallel state, the surface of the first metal layer 11 May be flattened by polishing or the like. For example, after the surface of the first metal layer 11 made of tungsten or the like is flattened, a plating layer such as a nickel plating layer or a gold plating layer is applied. preferable.

  A third bonding layer 10c and a fourth connection layer 10d that are electrically connected to the first electrode 8 and the first metal layer 11, respectively, are deposited on the lower surface of the first insulating plate 2. By connecting the first connection layer 10a and the third bonding layer 10c via the bonding material 12 such as solder, the wiring conductor 6a is connected to the first electrode 8, and the wiring conductor 6a is connected to the semiconductor. When the electrode of the element 4 is connected via a conductive bonding material 7 such as a solder bump, the electrode of the semiconductor element 4 and the first electrode 8 are electrically connected.

  Further, by joining the second connection layer 10b and the fourth connection layer 10d via the bonding material 12 such as solder, the wiring conductor 6b is connected to the first metal layer 11, and this wiring conductor 6b. When the electrode of the semiconductor element 4 is connected via the conductive bonding material 7 such as a solder bump, the electrode of the semiconductor element 4 and the first metal layer 11 are electrically connected.

  Further, in order to join the insulating base 1 and the first insulating plate 2 with high accuracy, the third bonding layer 10c and the fourth connection layer 10d are wider than the first connection layer 10a and the second connection layer 10b. It is preferable to form it small.

  Further, since the first insulating plate 2 is a flat plate, it can be easily formed as a flat one, and even if warping or the like occurs in the first insulating plate 2, processing such as polishing is performed. The surface of the first insulating plate 2 and the surface of the first electrode 8 can be easily made flat.

  Further, it is preferable that the first insulating plate 2 has such a thickness that the first insulating plate 2 is not warped or deformed by the influence of the conductive bonding material 12 or the like when bonded to the insulating substrate 1. . Thereby, the 1st electrode 8 and the 1st metal layer 11 can be made into a flat state, and it can make it easy to join the 2nd insulating board 3 mentioned later to a flat state.

  The second insulating plate 3 is joined to the upper surface of the first insulating plate 2 so as to form a sealed space with the first insulating plate 2. The second insulating plate 3 is made of ceramics or resin, and in the case of ceramics, the aluminum oxide sintered body, aluminum nitride sintered body, mullite sintered body, silicon nitride sintered body, silicon carbide As a so-called pressure detecting diaphragm which is a flat plate having a thickness of 0.01 to 5 mm made of an electrically insulating material such as a sintered body or glass ceramic, and bends toward the first insulating plate 2 in response to an external pressure. Function.

  In addition, since the mechanical strength of the second insulating plate 3 is small when the thickness is less than 0.01 mm, the second insulating plate 3 is easily broken when a large external pressure of, for example, about 80 kPa is applied thereto. On the other hand, if it exceeds 5 mm, it becomes difficult to bend at a pressure of, for example, about 2000 kPa, and the pressure detection diaphragm tends to have low detection accuracy. Therefore, the thickness of the second insulating plate 3 is preferably in the range of 0.01 to 5 mm.

  If such a second insulating plate 3 is made of, for example, an aluminum oxide sintered body, an organic binder, solvent, plasticizer suitable for ceramic raw material powders such as aluminum oxide, silicon oxide, magnesium oxide, and calcium oxide. , Dispersant is added and mixed to make a slurry, and this is formed into a sheet by using a conventionally known doctor blade method to obtain a ceramic green sheet. After that, the ceramic green sheet is appropriately punched. The green ceramic molded body for the second insulating plate 3 is obtained by processing and cutting, and the green ceramic molded body is manufactured by firing at a temperature of about 1600 ° C.

  In addition, a circular second electrode 9 for forming a capacitance is attached to the central portion of the main surface (the lower surface in FIG. 1) that is the inside of the sealed space of the second insulating plate 3. The second electrode 9 functions as an electrode for forming a capacitance for the pressure sensitive element together with the first electrode 8 described above.

The second electrode 9 is made of metal powder metallization such as tungsten, molybdenum, copper, and silver, and is obtained by adding and mixing an appropriate organic binder, solvent, plasticizer, and dispersant to metal powder such as tungsten. The paste is applied to a ceramic green sheet for the second insulating plate 3 by using a conventionally known screen printing method, and is fired together with a green ceramic molded body for the second insulating plate 3 to thereby produce the second insulating plate 3. It is formed in a predetermined pattern at the center of the lower surface. Since the lower surface of the second insulating plate 3 or the surface of the second electrode 9 is preferably flat, the surface of the second electrode 9 is preferably flattened by polishing or the like. For example, it is preferable to apply a plating layer such as a nickel plating layer or a gold plating layer after the surface of the second electrode 9 made of tungsten or the like is flattened. On the outer periphery of the second electrode 9, a second metal layer 13 is formed which forms a sealed space between the first insulating plate 2 and the second insulating plate 3 and is electrically connected to the second electrode 9. Is deposited. When the second metal layer 13 is joined to the first metal layer 11 described above, the wiring conductor 6b is connected, and the electrode of the semiconductor element 4 is connected to the wiring conductor 6b with a conductive bonding material 7 such as a solder bump. When the connection is made, the electrode of the semiconductor element 4 and the second electrode 9 are electrically connected.

  Such a second metal layer 13 is formed in the same manner as the second electrode 9 and is made of metal powder metallization such as tungsten, molybdenum, copper, silver, etc., and an appropriate organic binder, solvent, A metallized paste obtained by adding and mixing a plasticizer and a dispersing agent is printed and applied to a ceramic green sheet for the second insulating plate 3 using a conventionally known screen printing method, and then fired. 3 is formed into a predetermined frame-like pattern on the upper surface. The surface of the second metal layer 13 is nickel-plated with a thickness of about 1 to 10 μm to prevent the second metal layer 13 from being oxidatively corroded and to strengthen the bonding with the first insulating plate 2. It is preferable that the layer and the gold plating layer having a thickness of about 0.1 to 3 μm are sequentially deposited.

  In addition, since the surface of the second metal layer 13 is preferably flat in the same manner as the second electrode 9 in order to be joined in parallel with the first insulating plate 2, The surface may be flattened by polishing or the like. For example, after the surface of the second metal layer 13 made of tungsten or the like is flattened, a plating layer such as a nickel plating layer or a gold plating layer is applied. Is preferred.

  Preferably, the area of the second electrode 9 is larger than the area of the first electrode 8. Thereby, it can prevent effectively that the opposing area of the 2nd electrode 9 and the 1st electrode 8 varies by the slight shift | offset | difference at the time of joining the 2nd insulated substrate 3 to the 1st insulated substrate 2. FIG.

  More preferably, the second electrode 9 is deposited on almost the entire lower surface of the second insulating plate 3, and the outer peripheral portion of the second electrode 9 is a second metal layer 13 that serves as a joint with the first insulating plate 2. It is good. Thereby, the electrical connection reliability of the second electrode 9 is improved, and the capacity stability between the first electrode 8 and the second electrode 9 is also improved. In addition, since the metal layer is provided on almost the entire lower surface of the insulating plate 3, the insulating substrate 3 can be effectively prevented from being distorted. That is, when there are a portion with and without a metal layer on the lower surface of the insulating substrate 3, a difference in thermal expansion occurs between the portion with and without the metal layer, and the insulating substrate 3 is easily distorted. The presence of the metal layer on the entire lower surface of the substrate 3 makes it difficult for the difference in thermal expansion to occur and distortion to occur. As a result, the first electrode 8 and the second electrode 9 can be kept more parallel.

  Further, since the second insulating plate 3 is also a flat plate like the first insulating plate 2, it is easy to form as a flat one, and even if warpage or the like occurs, polishing processing or the like is performed. The surface of the second insulating plate 3 and the surface of the second electrode 9 can be easily made flat.

  Then, the first metal layer 11 of the first insulating plate 2 and the second metal layer 13 of the second insulating plate 3 are joined so as to form a space between the first electrode 8 and the second electrode 9. A predetermined capacitance is formed according to the area of the first electrode 8 and the second electrode 9 and the distance between the first electrode 8 and the second electrode 9. When an external pressure is applied to the upper surface of the second insulating plate 3, the second insulating plate 3 bends toward the first insulating plate 2 in accordance with the pressure, and the distance between the first electrode 8 and the second electrode 9 is increased. As a result, the capacitance between the first electrode 8 and the second electrode 9 changes, thereby functioning as a pressure-sensitive element that senses a change in external pressure as a change in capacitance. Then, the change in the electrostatic capacity is transmitted to the semiconductor element 4 accommodated in the recess 1a through the wiring conductors 6a and 6b, and this is processed by the semiconductor element 4 to know the magnitude of the external pressure. Can do.

  Therefore, according to the package for the pressure detection device of the present invention, the insulating base 1 having the mounting portion 1b on which the semiconductor element 4 is mounted on one main surface, and the surface and inside of the insulating base 1 are disposed. 4 is formed between the plurality of wiring conductors 6 to which the respective electrodes 4 are electrically connected, the first insulating plate 2 joined to the other main surface of the insulating base 1, and the first insulating plate 2. The second insulating plate 3 is joined to the outer peripheral portion of the first insulating plate 2 in a flexible state, and is attached to the main surface of the first insulating plate 2 in the sealed space. The first electrode 8 for forming capacitance that is electrically connected to the first electrode and the main surface of the second insulating plate 3 in the sealed space and electrically connected to the other one of the wiring conductors 6 Since the first insulating plate 2 and the second insulating plate 3 are made of flat plates, the second electrode 9 for forming electrostatic capacitance is provided. The surface of the first insulating plate 2 and the second insulating plate 3 can be easily processed such as polishing, and the surfaces of the first insulating plate 2 and the second insulating plate 3 can be flattened more easily. As a result, the first electrode 8 and the second electrode 9 can be easily formed flat on the upper surfaces of the first insulating plate 2 and the second insulating plate 3, respectively. Since it becomes easy to join the plate 3 in parallel and to form the first electrode 8 and the second electrode 9 in a parallel state, when the external pressure fluctuates, the first electrode 8 and the second electrode 9 It is possible to make uniform displacement with respect to the center of the electrode, to reduce variation in capacitance detected by the first electrode 8 and the second electrode 9, and to accurately detect external pressure. It becomes.

  Moreover, since both the surface of the 1st insulating board 2 and the surface of the 2nd insulating board 3 can be made excellent in smoothness, it respond | corresponds to these thickness through a very thin metal thin film, solder, etc. Thus, it is possible to form a sealed space with a very narrow interval between the first insulating plate 2 and the second insulating plate 3 with high accuracy, and the first and second electrodes 27 and 29 are made to face each other as in the past. When forming the sealed space for forming the capacitance, it is not necessary to form the frame-shaped protrusion 22b having a relatively large thickness, and the first electrode 8 and the second electrode 9 for obtaining a predetermined capacitance. The first insulating plate 2 and the second insulating plate 3 can be made smaller to make the package for the pressure detection device small, and the mass of the second insulating plate 3 and the second electrode 9 can be reduced. Can be made small, so centrifugal acceleration That the second can be made small deflection influence of the insulating plate 2, and that the external pressure can be accurately detected.

  Further, even if the main surface of the insulating substrate 1 is uneven or warped, it is formed between the first insulating plate 2 and the second insulating plate 3 bonded to the one main surface of the insulating substrate 1. Therefore, the external pressure can be accurately detected.

  A third metal layer 14 is formed on at least one surface of the first metal layer 11 and the second metal layer 13, and the first metal layer 11 and the second metal layer 13 are interposed via the third metal layer 14. It is preferable to join them with solder 15 such as gold-tin alloy. That is, the thickness of the first metal layer 11, the second metal layer 13, the third metal layer 14, and the solder 15 becomes the distance between the first insulating plate 2 and the second insulating plate 3, The metal layer 13, the third metal layer 14, and the solder 15 are thinner and easier to form than the conventional frame-like protrusion 22 b formed on the outer peripheral portion of the insulating base 21 or the insulating plate 22, and have a capacitance. The distance between the first electrode 8 and the second electrode 9 forming the electrode can be made small, and the sensitivity can be made high.

  Further, since the first metal layer 11 and the second metal layer 13 are joined by the solder 15 via the third metal layer 14, the first insulating plate 2 and the second insulating plate 3 are highly airtight. Since the pressure in the sealed space can be kept constant, the external pressure can be detected with high sensitivity.

  Moreover, since the space | interval of the 1st electrode 8 and the 2nd electrode 9 can be made small, since the area where the 1st electrode 8 and the 2nd electrode 9 which form required electrostatic capacitance can be made small, the 1st The one insulating plate 2 and the second insulating plate 3 can be made smaller, and accordingly, the insulating base 1 can also be made smaller, the pressure sensing device package of the present invention can be miniaturized, and the second insulating plate 3 Further, the mass of the second electrode 9 can be further reduced, the influence of centrifugal force can be reduced, and the external pressure can be formed with high accuracy.

  Further, if the solder 15 is thinly deposited by a thin film forming method or the like, the space between the first electrode 8 and the second electrode 9 can be made smaller, and the sensitivity can be made small.

  The third metal layer 14 is formed by, for example, depositing a metal such as gold of about 0.3 to 10 μm in a frame shape on the outer periphery of the second metal layer 13 by an electroless plating method or the like. 9, and the first metal layer 11 and the third metal layer 14 are joined together by solder 15, so that a sealed space is formed between the first insulating plate 2 and the second insulating plate 3. Form.

  The third metal layer 14 may be formed by attaching a metal plate such as a gold foil having a thickness of about 0.3 to 10 μm to the second metal layer 13 in a frame shape. Moreover, although the example in which the third metal layer 14 is formed on the surface of the second metal layer 13 has been shown, the third metal layer 14 is formed on the surface of the first metal layer 11, and the third metal layer 14 is formed on the outer periphery of the second insulating plate 3. The second metal layer 13 may be joined by solder 15. Alternatively, the third metal layer 14 may be formed on the respective surfaces of the first metal layer 11 and the second metal layer 13, and the third metal layers 14 may be joined together by the solder 15.

  Next, another example of the embodiment of the pressure detection device package of the present invention will be described below based on the sectional view of FIG. As shown in FIG. 2, the third metal layer 14 is formed on at least one surface of the first metal layer 11 and the second metal layer 13, and the first metal layer 11 and the first metal layer 11 formed on the first insulating plate 2 are It is preferable that the second metal layer 13 formed on the two insulating plates 3 is joined by thermocompression bonding via the third metal layer 14. That is, the thicknesses of the first metal layer 11, the second metal layer 13, and the third metal layer 14 become the distance between the first insulating plate 2 and the second insulating plate 3, and the first metal layer 11 and the second metal layer 13. And the third metal layer 14 are thinner and easier to form than the conventional frame-like protrusion 22b formed on the outer periphery of the insulating base 21 or the insulating plate 22, so that the first forming the capacitance The distance between the electrode 8 and the second electrode 9 can be made small.

  Further, since the first insulating plate 2 and the second insulating plate 3 are thermocompression bonded via the third metal layer 14, a bonding material such as a brazing material is used for the first insulating plate 2 and the second insulating plate 3. The first insulating plate 2 and the second insulating plate 3 are not parallel to each other and the first insulating plate 2 and the second insulating plate 3 are more parallel to each other. The external pressure can be accurately detected.

  Moreover, since the space | interval of the 1st electrode 8 and the 2nd electrode 9 can be made small, since the area where the 1st electrode 8 and the 2nd electrode 9 which form required electrostatic capacitance can be made small, the 1st The one insulating plate 2 and the second insulating plate 3 can be made smaller, and accordingly, the insulating base 1 can be made smaller, the pressure detecting device package of the present invention can be miniaturized, and the second insulating plate 3 and The mass of the second electrode 9 can be further reduced, and the influence of centrifugal force can be further reduced.

  Further, the first metal layer 11 and the second metal layer 13 are formed at the same time when the first electrode 8 and the second electrode 9 are formed. It can be set as the space | interval for forming an electrostatic capacitance between the one electrode 8 and the 2nd electrode 9, and it becomes easy to adjust the space | interval with the space | interval of the 1st electrode 8 and the 2nd electrode 9. FIG.

  The third metal layer 14 is formed by, for example, depositing a metal such as gold of about 0.3 to 10 μm on the outer peripheral portion of the second metal layer 13 in a frame shape by an electroless plating method or the like. The first metal layer 11 and the third metal layer 14 are thermocompression-bonded to form a sealed space between the first insulating plate 2 and the second insulating plate 3. .

  The third metal layer 14 may be formed by attaching a metal plate such as a gold foil having a thickness of about 0.3 to 10 μm to the outer peripheral portion of the second insulating plate 3 in a frame shape by thermocompression bonding or the like. Moreover, although the example in which the third metal layer 14 is deposited on the surface of the second metal layer 13 has been shown, the third metal layer 14 is deposited on the surface of the first metal layer 11, and the third metal layer 14 is separated from the second insulating plate. 3 may be bonded to the second metal layer 13 on the outer peripheral portion of the outer peripheral portion by thermocompression bonding. Moreover, the 3rd metal layer 14 may be formed in each surface of the 1st metal layer 11 and the 2nd metal layer 13, and these 3rd metal layers 14 may be joined by thermocompression bonding.

  In order to prevent a short circuit between the first electrode 8 and the second electrode 9, the first metal layer 11 may be thicker than the first electrode 8 by, for example, about 5 μm.

  Further, it is preferable that the outer peripheral portion of the joint portion between the first metal layer 11 and the second metal layer 13 joined through the third metal layer 14 is covered with a solder 16 such as a gold-tin alloy. . Thereby, the sealed space between the 1st insulating board 2 and the 2nd insulating board 3 joined by thermocompression bonding can be made more airtight. Moreover, since it can be made highly airtight, the pressure in the sealed space can be kept constant, and a compact package for a pressure detection device that can accurately detect external pressure can be obtained.

  Thus, according to the above-described package for a pressure detection device, the semiconductor element 4 is mounted on the mounting portion 1b and sealed, and the plurality of wiring conductors 6 to which the respective electrodes of the semiconductor element 4 are electrically connected are provided. As a result, it is possible to provide a package for a pressure detection device that is small in size and has high sensitivity and can accurately detect external pressure.

  The present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the gist of the present invention. For example, the third metal layer 14 may not be formed up to the outer periphery of the first metal layer 11 or the second metal layer 13, and the first insulating plate 2 and the second insulating plate are interposed via the third metal layer 14. 3, the solder 16 may cover the outer side surface of the third metal layer 14 and may cover the outer periphery of the first metal layer 11 or the second metal layer 13. Further, an insulating film may be deposited on at least one surface of the first electrode 8 and the second electrode 9. Thereby, when the 2nd insulating board 3 bends, it can prevent effectively that the 1st electrode 8 and the 2nd electrode 9 short-circuit.

  The first electrode 8, the second electrode 9, the first metal layer 11, and the second metal layer 13 may be formed by a thin film forming method. For example, the first insulating plate 2 and the second insulating plate 3 When made of ceramics, etc., the surface of the first insulating plate 2 or the second insulating plate 3 is flattened by polishing or the like, and then a metal such as nickel chrome alloy, titanium-tungsten alloy, gold, silver, copper, or aluminum is used. By using a thin film forming method such as a vapor deposition method, a predetermined pattern having a thickness of about 0.1 to 1.0 μm may be formed in the central portion of the upper surface of the insulating substrate 1. At this time, the surfaces of the first electrode 8, the second electrode 9, the first metal layer 11, and the second metal layer 13 are prevented from being oxidatively corroded, and the first metal layer 11 and the second metal layer 13 In order to strengthen the bonding, a metal film such as gold having a thickness of about 0.01 to 2.0 μm may be applied.

(A) is sectional drawing which shows an example of embodiment of the package for pressure detection apparatuses of this invention, (b) is a principal part enlarged view of (a). (A) is sectional drawing which shows the other example of embodiment of the package for pressure detection apparatuses of this invention, (b) is a principal part enlarged view of (a). It is sectional drawing which shows the package for the conventional pressure detection apparatus. It is sectional drawing which shows the package for the conventional pressure detection apparatus.

Explanation of symbols

1 ·········· Insulation base 1b ······ Mounting portion 2 ························ First insulation plate 3 2nd insulating plate 4 ... Semiconductor element 6, 6a, 6b Wiring conductor 8 ... First electrode 9 ················································································································ .... Third metal layer 15, 16, .... Solder

Claims (1)

An insulating base 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 base and electrically connected to the electrodes of the semiconductor element; Joined in a flexible state to the outer periphery of the first insulating plate so as to form a sealed space between the first insulating plate joined to the other main surface of the insulating base and the first insulating plate A second electrode formed on the main surface of the first insulating plate in the sealed space and electrically connected to one of the wiring conductors; A second electrode for forming a capacitance that is attached to the main surface of the second insulating plate in the sealed space and is electrically connected to the other one of the wiring conductors. A package for a pressure detection device.

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