JP2005134221A - Package for pressure detection device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a package for a pressure detection device having a small size and high sensitivity, which detects accurately the external pressure. <P>SOLUTION: This package for the pressure detection device is equipped with: an insulating substrate 1 having a loading part 1b for loading a semiconductor element 3 on one main surface thereof; a plurality of wire conductors 5 disposed on the surface and the inside of the insulating substrate 1, to which each electrode of the semiconductor element 3 is electrically connected; an insulating plate 2 bonded to the insulating substrate 1 in the flexible state so as to form a sealed space between itself and the other main surface of the insulating substrate 1; the first electrode 7 for capacitance formation adhering to the other main surface of the insulating substrate 1 in the sealed space and connected electrically to one of the wire conductors 5; and the second electrode 9 for capacitance formation adhering to the main surface inside the insulating plate 2 so as to face to the first electrode 7 and connected electrically to another of the wire conductors 5. The first electrode 7 and the second electrode 9 comprise a metallized layer whose surface is polished to form the flat surface. <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 sectional view in FIG. 6, this capacitance type pressure detection device has a capacitance type pressure sensitive element 32 and a pressure detection device package on a wiring board 31 made of a ceramic material or a resin material. 38 and a semiconductor element 39 for calculation contained in 38.

  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 detecting device, since the pressure sensitive element 32 and the semiconductor element 39 are individually mounted on the wiring board 31, the pressure detecting device is enlarged and the pressure detecting electrode 33, The wiring conductor between the semiconductor element 39 and the semiconductor element 39 becomes long, and an unnecessary capacitance is formed between the long wiring conductors, so that the sensitivity is low.

  Therefore, the applicant of the present application, as shown in a cross-sectional view in FIG. 5, has an insulating base 21 having a mounting portion 21b on which the semiconductor element 23 is mounted on one main surface, and is disposed on and inside the insulating base 21. A plurality of wiring conductors 25 to which the respective electrodes of the semiconductor element 23 are electrically connected and a central portion of the other main surface of the insulating base 21 are attached to the wiring conductor 25a which is one of the wiring conductors 25. 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. The bonded insulating plate 22 is attached to the inner main surface of the insulating plate 22 so as to face the first electrode 27, and is electrically connected to the wiring conductor 25b, which is another wiring conductor 25. Proposed package for pressure sensing device comprising second electrode 29 for capacitance formation And (see Patent Document 1 below).

  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 for the pressure detection device that accommodates the semiconductor element 23, the pressure detection device can be reduced in size and the pressure detection electrode By shortening the wiring conductor 5 connecting the semiconductor element 23, unnecessary capacitance generated between the wiring conductors 5 can be reduced.

  Conventionally, the first electrode 27 of these pressure detection device packages is made of metal powder metallization such as tungsten, molybdenum, copper, silver, etc., and an appropriate organic binder, solvent, plasticizer, and dispersant are applied to the metal powder such as tungsten. The metallized paste obtained by addition and mixing is applied to a ceramic green sheet for the insulating substrate 21 by employing a conventionally known screen printing method, and is fired together with the green ceramic molded body for the insulating substrate 21, thereby insulating the substrate. A predetermined pattern is formed at the center of the upper surface of 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 by using a well-known screen printing method, and fired together with a green ceramic molded body for the insulating plate 22 to form a predetermined pattern on the insulating plate 22. The

  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 insulating plate 22 is formed with a frame-like protrusion 22b on the outer periphery thereof, thereby forming a sealed space for forming a capacitance between the insulating base 21 and the insulating plate 22.

Further, 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 part or the frame-shaped protrusion 2b. And the second bonding metallization layer 30 were bonded by a brazing material or the like.
JP 2001-356064 A

  However, according to the conventional package for a pressure detection device, the first electrode 27 and the second electrode 29 are formed by the screen printing method. It is difficult to make the distance between the two electrodes 29 uniform, and the capacitance generated between the first electrode 27 and the second electrode 29 varies, and the sensitivity tends to decrease. It was.

  In addition, when the action of centrifugal force is applied to the upper surface of the insulating plate 22, the insulating plate 22 is easily displaced by the mass of the second electrode 29 or the insulating plate 22, and the gap between the first electrode 27 and the second electrode 29 is increased. However, it is difficult to accurately detect the external pressure by affecting the capacitance generated between the first electrode 27 and the second electrode 29.

  Further, when joining the insulating base 21 and the insulating plate 22, it is difficult to make the thickness of the brazing material uniform over the entire circumference between the insulating base 21 and the insulating plate 22. The insulating base 21 and the insulating plate 22 are not brazed in parallel, and an inclination is generated between the first electrode 27 and the second electrode 29, so that the detection sensitivity is likely to vary. It was.

  Further, in order to be able to detect the external pressure with high sensitivity, the frame-shaped protrusion 22b on the outer peripheral portion of the insulating base 21 or the insulating plate 22 is lowered, and the first electrode 27, the second electrode 29, There is a method of reducing the amount of displacement due to external pressure by narrowing the interval of the insulating plate 22 or thinning the insulating plate 22, but the frame-shaped protrusion 22 b on the outer peripheral portion of the insulating base 21 or the insulating plate 22 is formed low. In the case where the frame-like projection 22b is formed low, when the pressure is applied to the outside, the junction or insulation between the frame-like projection 22b and the insulating base 21 or the insulating plate 22 is insulated. There has been a problem that cracks and cracks are likely to occur at the joint between the plate 22 and the brazing material.

  Accordingly, the present invention has been devised in view of such conventional problems, and an object thereof is a package for a pressure detection device that is small in size and hardly affected by centrifugal force and has high sensitivity for detecting external pressure. Is to provide.

  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 An insulating plate joined to the insulating substrate in a flexible state so as to form a sealed space between the plurality of wiring conductors connected to the other main surface of the insulating substrate, and the inside of the sealed space A first electrode for forming a capacitance that is attached to the other main surface of the insulating base and is electrically connected to one of the wiring conductors, and a first electrode on the inner main surface of the insulating plate. A package for a pressure detection device, comprising: a second electrode for forming a capacitance, which is attached to face the electrode and is electrically connected to the other one of the wiring conductors, The electrode and the second electrode are metallized layers whose surfaces are polished and flat. Is characterized in that the made.

  In the pressure detection device package of the present invention, preferably, the insulating plate is warped so that a central portion thereof is convex toward the insulating base.

  Further, the pressure detection device package according to the present invention is preferably configured so that the second electrode is thinner than the first electrode.

  In the pressure detecting device package according to the present invention, preferably, the first metal layer is formed around the first electrode on the other main surface of the insulating base, and the insulating plate A second metal layer is formed around the second electrode on the inner main surface, and a third metal layer is formed on at least one surface of the first metal layer and the second metal layer. The first metal layer and the second metal layer are brazed via the third metal layer.

  In the pressure detecting device package according to the present invention, preferably, the first metal layer is formed around the first electrode on the other main surface of the insulating base, and the insulating plate A second metal layer is formed around the second electrode on the inner main surface, and a third metal layer is formed on at least one surface of the first metal layer and the second metal layer. The first metal layer and the second metal layer are joined by thermocompression bonding.

  Further, the pressure detecting device package according to the present invention is preferably characterized in that the outer peripheral portion of the first to third metal layers is covered with a brazing material in the above configuration.

  According to the pressure detection device package of the present invention, the first electrode and the second electrode are formed of a metallized layer whose surface is polished to be a flat surface. It is easy to make the distance between the first electrode and the second electrode uniform over the entire surface, and the external pressure can be detected with high accuracy.

  Moreover, since the surface of the second electrode is thinly formed by polishing, the mass of the second electrode applied to the insulating plate is reduced, and the displacement due to the mass of the second electrode is reduced when subjected to the action of centrifugal force. be able to. In addition, since it is easy to form the insulating plate as a thin and flat one, it is possible to detect the external pressure with high sensitivity and to reduce the area of the insulating plate and the second electrode for obtaining a required capacity. In addition, the influence of centrifugal acceleration can be reduced by further reducing the mass of the insulating plate and the second electrode.

  Further, according to the pressure detection device package of the present invention, since the central portion of the insulating plate is warped so as to protrude toward the insulating base, the warp is further increased when receiving external pressure. It only needs to be displaced, and there is no inflection point where the insulating plate is easily bent and the insulating plate protrudes from the opposite side of the insulating substrate to the insulating substrate. For this reason, it is possible to provide a pressure detection device capable of accurately detecting the external pressure because the insulating plate is always bent in proportion to the external pressure.

  Further, according to the package for a pressure detection device of the present invention, since the second electrode is thinner than the first electrode, the mass of the second electrode can be reduced, so that when the centrifugal acceleration is applied, the second electrode The displacement received by the mass of can be reduced. Therefore, the external pressure can be detected with high accuracy. In addition, since the first electrode is thicker than the second electrode, stray capacitance can be effectively blocked by the first electrode between the wiring conductor and the like inside the insulating base and the second electrode. The influence of stray capacitance on the capacitance detected between the electrode and the second electrode can be reduced. Therefore, the external pressure can be detected with high accuracy.

  According to the pressure detection device package of the present invention, the first metal layer is formed around the first electrode on the other main surface of the insulating base, and the second electrode on the inner main surface of the insulating plate. A second metal layer is formed around the first metal layer, and a third metal layer is formed on at least one surface of the first metal layer and the second metal layer. Since the third metal layer is brazed via the third metal layer, the thickness of the third metal layer and the brazing material becomes the distance between the first electrode and the second electrode, and the third metal layer and the brazing material are insulated substrates. Or since it is easy to form thinner than the conventional frame-shaped projection part formed in the outer peripheral part of an insulating board, the space | interval of the 1st electrode and 2nd electrode which form an electrostatic capacitance can be made small.

  Moreover, since the first metal layer and the second metal layer are firmly bonded by the brazing material via the third metal layer, the insulating base and the insulating plate can be bonded as highly airtight, The pressure inside the sealed space can be kept constant and the external pressure can be detected with high sensitivity.

  Furthermore, since the interval between the first electrode and the second electrode can be reduced, the area where the first electrode and the second electrode that form the required electrostatic capacitance can be reduced to reduce the insulating plate, The package for a pressure detection device of the present invention can be miniaturized, the mass of the insulating plate and the second electrode can be further reduced, and the influence of centrifugal force can be further reduced.

  According to the pressure detection device package of the present invention, the first metal layer is formed around the first electrode on the other main surface of the insulating base, and the second electrode on the inner main surface of the insulating plate. A second metal layer is formed around the first metal layer, and a third metal layer is formed on at least one surface of the first metal layer and the second metal layer. Since it is joined by thermocompression bonding, the thickness of the third metal layer becomes the distance between the first electrode and the second electrode, and the third metal layer is a conventional frame formed on the outer periphery of the insulating base or insulating plate. Therefore, the distance between the first electrode and the second electrode forming the electrostatic capacity can be made small.

  In addition, since the first metal layer and the second metal layer are thermocompression bonded via the third metal layer, the insulating base and the insulating plate can be bonded without using a bonding material such as a brazing material, and bonded at the time of bonding. It is possible to effectively prevent the thickness of the material from being biased and to make the insulating base and the insulating plate extremely parallel. As a result, the external pressure can be detected with higher accuracy.

  In addition, since the distance between the first electrode and the second electrode can be reduced, the opposing area between the first electrode and the second electrode that forms the required capacitance can be reduced, so the insulating plate is made smaller. In addition, the pressure detection device package of the present invention can be miniaturized, the mass of the insulating plate and the second electrode can be further reduced, and the influence of centrifugal force can be further reduced.

  Moreover, according to the package for a pressure detection device of the present invention, since the outer peripheral portions of the first to third metal layers are covered with the brazing material, the gap between the insulating base and the insulating plate joined by thermocompression bonding. By further sealing the sealed space with the brazing material on the outer peripheral portion, it is possible to further increase the airtightness. Therefore, since the pressure in the sealed space can be kept constant, it is possible to provide a small pressure detection device package that can accurately detect the external pressure when the external pressure changes.

  Next, the pressure detection device package of the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1A is a cross-sectional view showing an example of an embodiment of a pressure detection device package according to the present invention, FIG. 1B is an enlarged view of a main part of FIG. 2 is an insulating plate, 3 is a semiconductor element, 7 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 3 formed on one main surface (lower surface in FIG. 1), thereby functioning as a container for accommodating the semiconductor element 3. The central portion of the bottom surface of the recess 1a serves as a mounting portion 1b on which the semiconductor element 3 is mounted. The semiconductor element 3 is mounted on the mounting portion 1b and is sealed with a resin such as an epoxy resin in the recess 1a. The semiconductor element 3 is sealed by covering the semiconductor element 3 with the material 4.

  In this example, the semiconductor element 3 is sealed by covering the semiconductor element 3 with a resin sealing material 4. However, the semiconductor element 3 has a lid made of metal or ceramics on one main surface of the insulating substrate 1. You may seal by making it join so that the recessed part 1a may be plugged up.

  In addition, a plurality of wiring conductors 5 connected to the respective electrodes of the semiconductor element 3 are led out to the mounting portion 1b. The wiring conductors 5 and the respective electrodes of the semiconductor element 3 are electrically conductive made of a conductive material such as a solder bump. The electrodes of the semiconductor element 3 and the wiring conductors 5 are electrically connected to each other through the bonding material 6 and the semiconductor element 3 is fixed to the mounting portion 1b. In this example, the electrode of the semiconductor element 3 and the wiring conductor 5 are connected via solder bumps, but the electrode of the semiconductor element 3 and the wiring conductor 5 are connected to other electrical connection means such as bonding wires. May be connected.

  The wiring conductor 5 functions as a conductive path for electrically connecting each electrode of the semiconductor element 3 to the external electric circuit and the first electrode 7 and the second electrode 9, and a part of the wiring conductor 5 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 7 and the second electrode 9. Each electrode of the semiconductor element 3 is electrically connected to these wiring conductors 5 through a conductive bonding material 6 such as a solder bump and the semiconductor element 3 is sealed with a resin sealing material 4. A portion led out to the outer peripheral portion of one main surface of the insulating base 1 of the conductor 5 is accommodated inside by joining to a wiring conductor (not shown) of the external electric circuit board via a conductive bonding material such as solder. The semiconductor element 3 is electrically connected to the external electric circuit.

  Such a wiring conductor 5 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 5 has a thickness of 1 in order to prevent the wiring conductor 5 from being oxidatively corroded and to improve the bonding between the wiring conductor 5 and the conductive bonding material 6 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.

  In addition, a first electrode 7 for forming a capacitance is attached to the central portion of the other main surface (upper surface in FIG. 1) of the insulating substrate 1. The first electrode 7 is for forming a capacitance for the pressure sensitive element together with the second electrode 9 and is formed in, for example, a circular pattern. A wiring conductor 5a is electrically connected to the first electrode 7. A semiconductor element is formed by connecting the electrode of the semiconductor element 3 to the wiring conductor 5a via a conductive bonding material 6 such as a solder bump. 3 and the first electrode 7 are electrically connected.

  The first electrode 7 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 printed and applied to a ceramic green sheet for the insulating substrate 1 using a conventionally known screen printing method, and is fired to form a predetermined pattern in the center of the upper surface of the insulating substrate 1. The exposed surface of the first electrode 7 is usually coated with a nickel plating layer having a thickness of about 1 to 10 μm to prevent the first electrode 7 from being oxidized and corroded. Is preferred.

  A first metal layer 8 serving as a bonding portion for bonding the insulating plate 2 to the insulating substrate 1 is attached to the other main surface of the insulating substrate 1 around the first electrode 7. By being joined to the second metal layer 10 that is the joining portion of the two, it is electrically joined to the second electrode 9 of the insulating plate 2.

  A wiring conductor 5b, which is one of the wiring conductors 5, is connected to the first metal layer 8 at the joint portion of the insulating base 1, and the electrode of the semiconductor element 3 is connected to the wiring conductor 5b with a conductive property such as a solder bump. By being electrically connected via the bonding material 6, the second electrode 9 electrically connected to the first metal layer 8 and the electrode of the semiconductor element 3 are electrically connected.

  The first metal layer 8 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. Is applied to a ceramic green sheet for the insulating substrate 1 by using a well-known screen printing method, and is fired together with the ceramic molded body for the insulating substrate 1 to thereby insulate the insulating substrate 1 around the first electrode 7. Is formed in a predetermined frame-like pattern on the other main surface. In addition, in order to prevent the first metal layer 8 from being oxidatively corroded on the exposed surface of the first metal layer 8 and to strengthen the bonding with the second metal layer 10 described later, it is usual. If present, it is preferable that a nickel plating layer 8a having a thickness of about 1 to 10 μm is applied.

  The insulating plate 2 attached to the other main surface (upper surface) of the insulating substrate 1 so as to form a sealed space between the insulating substrate 1 and the insulating substrate 1 is made of ceramic, and is made of an aluminum oxide sintered body or aluminum nitride. A flat plate having a thickness of 0.01 to 5 mm made of an electrically insulating material such as a sintered compact, a mullite sintered body, a silicon nitride sintered body, a silicon carbide sintered body, and a glass ceramic. It functions as a so-called pressure detection diaphragm that bends toward the insulating substrate 1 in accordance with the pressure of the pressure.

  The insulating plate 2 has a mechanical strength of less than 0.01 mm, and is easily damaged when a large external pressure of, for example, about 80 kPa is applied thereto. For example, it becomes difficult to bend at a pressure of about 2000 kPa, and it tends to be unsuitable as a pressure detection diaphragm. Therefore, the thickness of the insulating plate 2 is preferably in the range of 0.01 to 5 mm.

  When such an insulating plate 2 is made of, for example, an aluminum oxide sintered body, an organic binder, a solvent, a plasticizer, a dispersion suitable for ceramic raw material powders such as aluminum oxide, silicon oxide, magnesium oxide, and calcium oxide are used. A ceramic green sheet is obtained by adding and mixing the agent to form a slurry, and forming this into a sheet by employing a conventionally known doctor blade method. After that, an appropriate punching process is performed on the ceramic green sheet. The raw ceramic molded body for the insulating plate 2 is obtained by cutting, and the raw ceramic molded body is manufactured by firing at a temperature of about 1600 ° C.

  In addition, a 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 inner side of the sealed space of the insulating plate 2. The second electrode 9 functions as an electrode for forming a capacitance for the pressure sensitive element by being arranged so as to face the first electrode 7 described above.

  The second electrode 9 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. The paste is printed and applied to a ceramic green sheet for the insulating plate 2 by employing a conventionally known screen printing method, and is baked to form a predetermined pattern at the center of the lower surface of the insulating plate 2. In order to prevent the first electrode 7 from being oxidatively corroded on the exposed surface of the second electrode 9, a nickel plating layer having a thickness of about 1 to 10 μm is usually applied. Is preferred.

  In addition, a second metal layer electrically connected to the second electrode 9 is provided on the lower surface of the insulating plate 2 around the second electrode 9 as a bonding portion for bonding the insulating plate 2 to the insulating base 1. 10 is attached, and is bonded to the first metal layer 8 serving as a bonding portion of the insulating plate 2, and the electrode of the semiconductor element 3 is connected to the wiring conductor 5b through the conductive bonding material 6 such as a solder bump. By doing so, the electrode of the semiconductor element 3 and the second electrode 9 are electrically connected.

  The second metal layer 10 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 substrate 1 by using a well-known screen printing method, and this is fired together with a ceramic molded body for the insulating plate 2 to thereby insulate the insulating plate 2 around the second electrode 9. A predetermined frame-like pattern is formed on the lower surface of the substrate. In addition, in order to prevent the second metal layer 10 from being oxidized and corroded on the exposed surface of the second metal layer 10 and to strengthen the bonding with the first metal layer 8, it is normal. A nickel plating layer 10a having a thickness of about 1 to 10 μm is applied.

  The second electrode 9 may be deposited on almost the entire main surface of the insulating plate 2, the outer periphery of the second electrode 9 may be the second metal layer 10, and the second electrode 9 may be formed on the main surface of the insulating plate 2. A second metal layer 10 may be separately formed on the main surface of the insulating plate 2 around the second electrode 9 and electrically connected to the second electrode 9 while being deposited on the central portion.

  By joining the first metal layer 8 and the second metal layer 10 so as to form a space between the first electrode 7 and the second electrode 9, the opposing area of the first electrode 7 and the second electrode 9 and A predetermined capacitance is formed according to the distance between the first electrode 7 and the second electrode 9. When an external pressure is applied to the upper surface of the insulating plate 2, the insulating plate 2 is bent toward the insulating base 1 in accordance with the pressure, and the distance between the first electrode 7 and the second electrode 9 is changed. Since the capacitance between the electrode 7 and the second electrode 9 changes, it functions as a pressure-sensitive element that senses a change in external pressure as a change in capacitance. Then, the change in electrostatic capacity is transmitted to the semiconductor element 3 accommodated in the recess 1a through the wiring conductors 5a and 5b, and this is processed by the semiconductor element 3 so as to know the magnitude of the external pressure. Can do.

  In the present invention, each of the first electrode 7 and the second electrode 9 is made of a metallized layer whose surface is polished to be a flat surface. In addition, since variations in thickness of each of the first electrodes 7 and the portions of the second electrode 9 can be easily reduced, variations in the distance between the respective portions of the first electrode 7 and the second electrode 9 can be made constant, and the external pressure can be made accurate. It can be detected well.

  Further, since the second electrode 9 is made of a metallized layer whose surface is polished to be a flat surface, the second electrode 9 can be formed thin on the lower surface of the insulating plate 2 and the mass of the second electrode 9 can be reduced. I can do it. Therefore, by forming the second electrode 9 to be thin and small and lowering the mass, the amount of displacement of the insulating plate 2 due to centrifugal acceleration is reduced, so that the influence of centrifugal acceleration can be reduced.

  Note that the surfaces of the first metal layer 8 and the second metal layer 10 are preferably polished and flat as in the case of the first electrode 7 and the second electrode 9. 2 can be accurately joined in parallel.

  In the pressure detection device package of the present invention, preferably, the insulating plate 2 is warped so that the central portion is convex toward the insulating base 1 side. Thus, when the external pressure is applied, it is only necessary to displace the warp to further increase, the insulating plate 2 is easily bent, and the insulating base 2 protrudes from the side opposite to the insulating base 1. There is no inflection point that protrudes to the side. Therefore, it is possible to provide a pressure detection device capable of accurately detecting the external pressure because the insulating plate 2 is always bent in proportion to the external pressure.

  Further, as shown in FIG. 2A in a sectional view and in FIG. 2B in an enlarged sectional view of the main part of FIG. 2A, the second electrode 9 is in a state where the pressure in the sealed space is the same as that in the outside. The insulating plate 2 may be warped so that the central portion is convex toward the insulating base 1 and the surface of the second electrode 7 may be polished so as to be parallel to the first electrode 7. Thereby, the thickness of the second electrode 9 at the central portion where the insulating plate 2 is most displaced is thin, the thickness of the second metal layer 10 is increased, and the displacement received by the mass of the second electrode 9 when centrifugal acceleration is applied. In addition to being able to reduce the size, the insulating plate 2 can be firmly bonded to the insulating substrate 1.

  In the pressure detection device package of the present invention, the second electrode 9 is preferably thinner than the first electrode 7. Thereby, since the mass of the 2nd electrode 9 can be made small, the displacement received by the mass of the 2nd electrode 9 when centrifugal acceleration is added can be made small. Therefore, the external pressure can be detected with high accuracy. Further, since the first electrode 7 is thicker than the second electrode 9, it is effective by the first electrode 7 that stray capacitance is generated between the wiring conductor 5 and the like inside the insulating base 1 and the second electrode 9. Therefore, the influence of the stray capacitance on the capacitance detected between the first electrode 7 and the second electrode 9 can be reduced. Therefore, the external pressure can be detected with high accuracy.

  In the pressure detection device package according to the present invention, preferably, the first metal layer 8 is formed around the first electrode 7 on the other main surface of the insulating base 1 in the above configuration, and the insulating plate 2 A second metal layer 10 is formed around the second electrode 9 on the inner main surface, and a third metal layer 11 is formed on at least one surface of the first metal layer 8 and the second metal layer 10. At the same time, the first metal layer 8 and the second metal layer 10 are brazed via the third metal layer 11. As a result, the thickness of the third metal layer 11 and the brazing material 12 becomes the distance between the first electrode 7 and the second electrode 9, and the third metal layer 11 and the brazing material 12 are formed on the insulating base 1 or the insulating plate 2. Since it is easy to form thinner than the conventional frame-shaped protrusion 22b formed on the outer peripheral portion, the distance between the first electrode 7 and the second electrode 9 forming the capacitance can be reduced.

  Further, since the first metal layer 8 and the second metal layer 10 are firmly joined by the brazing material 12 via the third metal layer 11, the insulating base 1 and the insulating plate 2 are made highly airtight. The pressure in the sealed space can be kept constant and the external pressure can be detected with high sensitivity.

  Moreover, since the space | interval of the 1st electrode 7 and the 2nd electrode 9 can be made small, the area which the 1st electrode 7 and the 2nd electrode 9 which form required electrostatic capacitance oppose is made small, and the insulating board 2 is made small. The pressure detecting device package of the present invention can be downsized, the mass of the insulating plate 2 and the second electrode 9 can be further reduced, and the influence of centrifugal force can be further reduced.

  Further, the brazing material 12 is made of gold-tin alloy solder or the like, and if it is thinly deposited by a thin film forming method or the like, the space between the first electrode 7 and the second electrode 9 becomes smaller, and the sensitivity is low. It can be high and small.

  The third metal layer 11 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 peripheral portion of the second metal layer 10 by an electroless plating method or the like. 9 and the first metal layer 8 and the third metal layer 11 are joined by the brazing material 12 to form a sealed space between the insulating base 1 and the insulating plate 2. At the same time, the first metal layer 8 and the second metal layer 10 are electrically connected to electrically connect the second electrode 9 to the semiconductor element 3.

  The third metal layer 11 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 insulating plate 2 in a frame shape. Moreover, although the example in which the third metal layer 11 is formed on the surface of the second metal layer 10 is shown, the third metal layer 11 is formed on the surface of the first metal layer 8, and the third metal layer 11 is formed on the outer peripheral portion of the insulating plate 2. The second metal layer 10 may be joined by the brazing material 12. Alternatively, the third metal layer 11 may be formed on the surfaces of the first metal layer 8 and the second metal layer 10, and the third metal layers 11 may be joined to each other by the brazing material 12.

  In addition, as shown in a cross-sectional view of another example of the pressure detection device package of the present invention in FIG. 3, the pressure detection device package of the present invention preferably has the other main surface of the insulating substrate 1 in the above configuration. A first metal layer 8 is formed around the first electrode 7, and a second metal layer 10 is formed around the second electrode 9 on the inner main surface of the insulating plate 2. A third metal layer 11 is formed on at least one surface of 8 and the second metal layer 10, and the first metal layer 8 and the second metal layer 10 are joined by thermocompression bonding. As a result, the thickness of the third metal layer 11 becomes the distance between the first electrode 7 and the second electrode 9, and the third metal layer 11 is a conventional frame shape formed on the outer peripheral portion of the insulating base 1 or the insulating plate 2. Therefore, the distance between the first electrode 7 and the second electrode 9 forming the electrostatic capacity can be made small.

  Further, since the first metal layer 8 and the second metal layer 10 are thermocompression bonded via the third metal layer 11, the insulating base 1 and the insulating plate 2 are bonded without using a bonding material such as a brazing material. In addition, it is possible to effectively prevent the thickness of the bonding material from being biased at the time of bonding, and the insulating base 1 and the insulating plate 2 can be made extremely parallel. As a result, the external pressure can be detected with higher accuracy.

  Furthermore, since the distance between the first electrode 7 and the second electrode 9 can be reduced, the opposing area between the first electrode 7 and the second electrode 9 that forms the required capacitance can be reduced, so The plate 2 can be made smaller, the pressure detection device package of the present invention can be miniaturized, the mass of the insulating plate 2 and the second electrode 9 can be further reduced, and the influence of centrifugal force can be further reduced. Can do.

  Further, the first metal layer 8 and the second metal layer 10 are formed at the same time when the first electrode 7 and the second electrode 9 are formed. An interval for forming a capacitance between the one electrode 7 and the second electrode 9 can be set, and the interval between the first electrode 7 and the second electrode 9 or the interval between the insulating substrate 1 and the insulating plate 2. It will be easier to adjust.

  The third metal layer 11 is formed by, for example, depositing a metal such as gold of about 0.3 to 10 μm on the outer periphery of the second metal layer 10 in a frame shape by an electroless plating method or the like. The first metal layer 8 and the third metal layer 11 are thermocompression-bonded to form a sealed space between the insulating base 1 and the insulating plate 2, and the first metal layer 8 and the third metal layer 11. The metal layer 8 and the second metal layer 10 are electrically connected, and the second electrode 9 is electrically connected to the semiconductor element 3.

  The third metal layer 11 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 periphery of the insulating plate 2 in a frame shape by thermocompression bonding or the like. Moreover, although the example in which the third metal layer 11 is deposited on the surface of the second metal layer 10 is shown, the third metal layer 11 is deposited on the surface of the first metal layer 8, and the third metal layer 11 is attached to the outer periphery of the insulating plate 2. You may join to the 2nd metal layer 10 of a part by thermocompression bonding. Moreover, the 3rd metal layer 11 may be formed in each surface of the 1st metal layer 8 and the 2nd metal layer 10, and these 3rd metal layers 11 may be joined by thermocompression bonding.

  In order to prevent a short circuit between the first electrode 7 and the second electrode 9, the first metal layer 8 may be thicker than the first electrode 7 by, for example, about 5 μm.

  Further, as shown in a cross-sectional view of another example of the pressure detection device package of the present invention in FIG. 3, the pressure detection device package of the present invention preferably has the first to third metal layers 8, 8 in the above configuration. 10 and 11 are covered with a brazing material 13 such as gold-tin alloy solder. Thereby, by further sealing the sealed space between the insulating base 1 and the insulating plate 2 joined by thermocompression bonding with the brazing filler metal 13 at the outer peripheral portion, it is possible to further increase the airtightness. Therefore, since the pressure in the sealed space can be kept constant, it is possible to provide a small pressure detection device package that can accurately detect the external pressure when the external pressure changes.

  Thus, according to the package for a pressure detection device of the present invention, the first electrode 7 for forming a capacitance is attached to the other main surface of the insulating substrate 1 on which the semiconductor element 3 is mounted on one main surface. In addition, the inner surface of the insulating plate 2 joined to the insulating substrate 1 in a flexible state so as to form a sealed space with the insulating substrate 1 is covered with the first electrode 7 so as to face the first electrode 7. Since the attached second electrode 9 for forming a capacitance is provided, the container for housing the semiconductor element 3 and the pressure sensitive element are integrated, and as a result, the pressure detecting device can be miniaturized.

  Further, the first electrode 7 and the second electrode 9 for forming capacitance are connected to the respective electrodes of the semiconductor element 3 via the wiring conductors 5a and 5b disposed on the surface and inside of the insulating base 1. The first electrode 7 and the second electrode 9 can be connected to the semiconductor element 3 at a short distance. As a result, unnecessary capacitance generated between the wiring conductors 5a and 5b is reduced, and the sensitivity is high. A package for a pressure detection device can be provided.

  Thus, according to the above-described pressure detection device package, the semiconductor element 3 is mounted on the mounting portion 1b and sealed, and the plurality of wiring conductors 5 to which the respective electrodes of the semiconductor element 3 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, as shown in FIG. 4, the third metal layer 11 may not be formed up to the outer periphery of the first metal layer 8 or the second metal layer 10, and the insulating substrate 1 is interposed via the third metal layer 11. After joining the insulating plate 2, the brazing material 13 may cover the outer periphery of the third metal layer 11 and the outer periphery of the first metal layer 8 or the second metal layer 10. Further, an insulating film may be deposited on at least one surface of the first electrode 7 and the second electrode 9. By applying an insulating film to at least one of the first electrode 7 and the second electrode 9, it is possible to effectively prevent the first electrode 7 and the second electrode 9 from being short-circuited when the insulating plate 2 is bent. can do.

  The present invention can be used for a pressure detection device for detecting a pressure state of a tire or the like.

(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 expanded sectional view for the pressure detection apparatuses 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 expanded sectional view for the pressure detection apparatus 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 expanded sectional view for the pressure detection apparatus 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 expanded sectional view for the pressure detection apparatus of (a). It is sectional drawing of the conventional package for pressure detection apparatuses. It is sectional drawing which shows the other example of the conventional package for pressure detectors.

Explanation of symbols

1 ·········· Insulation base 1b ····· Mounting portion 2 ··············· Insulating plate 3 ... Semiconductor element 5, 5a, 5b ... Wiring conductor 7 ... First electrode 8 ... First metal layer 9 2nd electrode 10 ... 2nd metal layer 11 ... 3rd metal layer 12 ... ··· Brazing filler metal 13

Claims (6)

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; An insulating plate joined to the insulating base in a flexible state so as to form a sealed space with the other main surface of the insulating base; and the other main surface of the insulating base in the sealed space. A first electrode for forming a capacitance that is attached and electrically connected to one of the wiring conductors, and is attached to the inner main surface of the insulating plate so as to face the first electrode; And a second electrode for forming a capacitance electrically connected to the other one of the wiring conductors, wherein the first electrode and the second electrode have a polished surface. For a pressure sensing device, characterized by comprising a metallized layer formed into a flat surface Package. 2. The package for a pressure detecting device according to claim 1, wherein the insulating plate is warped so that a central portion is convex toward the insulating base. The package for a pressure detection device according to claim 1, wherein the second electrode is thinner than the first electrode. A first metal layer is formed around the first electrode on the other main surface of the insulating base, and a second metal layer is formed around the second electrode on the inner main surface of the insulating plate. A third metal layer is formed on at least one surface of the first metal layer and the second metal layer, and the first metal layer and the second metal layer are brazed. The pressure detection device package according to any one of claims 1 to 3, wherein the pressure detection device package is provided. A first metal layer is formed around the first electrode on the other main surface of the insulating base, and a second metal layer is formed around the second electrode on the inner main surface of the insulating plate. A third metal layer is formed on at least one surface of the first metal layer and the second metal layer, and the first metal layer and the second metal layer are joined by thermocompression bonding. The package for a pressure detection device according to any one of claims 1 to 3, wherein the package is a pressure detection device. 6. The package for a pressure detection device according to claim 5, wherein an outer peripheral portion of the first to third metal layers is covered with a brazing material.

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