JP2005156433A - Package for pressure-detecting device and manufacturing method therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a compact package for a pressure-detecting device, which has high sensitivity for detecting external pressures and can accurately detect the external pressures, over a long period of time. <P>SOLUTION: The package for the pressure detecting device comprises an insulating substrate 1, having a mount section 1b in its one main surface, on which a semiconductor element 3 is mounted; wiring conductors 5 which are disposed on and inside the insulating substrate 1 and by which the semiconductor element 3 is electrically connected; an insulating plate 2 which is bonded to the insulating substrate 1 flexibly so as to form a sealed space between itself and the other main surface of the insulating substrate 1; a first electrode 7, which is attached to the other main surface of the insulating substrate 1 in the sealed space, electrically connected to one of the wiring conductors 5 and used for making up a capacitor; and a second electrode 9 which is attached to the inner main surface of the insulating plate 2 so as to be opposite to the first electrode 7, electrically connected to another wiring conductor 5 and used for making up the capacitor. A recessed section is formed in the main surface of the insulating plate 2 which is on the sealed space side, and a concave curve is formed between the inner wall and the bottom plate section 2b of the recessed section. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a pressure detection device package used in a pressure detection device for detecting pressure and a method of manufacturing the same.

  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. 5, the capacitance type pressure detection device includes a capacitance type pressure sensitive element 32 and a pressure detection device package on a wiring substrate 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, as shown in a cross-sectional view in FIG. 4, an insulating base 21 having a mounting portion 21 b on which the semiconductor element 23 is mounted on one main surface, and the surface and inside of the insulating base 21 are provided. A plurality of wiring conductors 25 that are electrically connected to each other and a central portion of the other main surface of the insulating base 21 are attached to the wiring conductor 25a that is one of the wiring conductors 25. Insulating plate joined in a flexible state so as to form a sealed space between the first electrode 27 for forming capacitance and the other main surface of the insulating base 21 with the central portion of the main surface. 22 and an inner main surface of the insulating plate 22 so as to be opposed to the first electrode 27 and electrically connected to a wiring conductor 25b which is another one of the wiring conductors 25. A package for a pressure detection device comprising a second electrode 29 has been proposed (bottom See Patent Document 1).

  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 projection 22a on the outer periphery thereof, thereby forming a sealed space for forming a capacitance between the insulating base 21 and the insulating plate 22.

As a method of forming the insulating plate 2 having such a protruding portion 22a, conventionally, a ceramic green sheet for the protruding portion 22a in which a through hole for forming a sealed space is formed by a punching method or the like, and the second electrode 29 are formed. The green sheet for the insulating plate 2 is formed by laminating the ceramic green sheet for the flexible portion 22b on which is formed.
JP 2001-356064 A

  However, according to the conventional package for a pressure detection device, when the flexible portion 22b of the insulating plate 22 is bent due to external pressure, it is generated by bending at the corners of the protruding portion 22a and the flexible portion 22b. Since stress tends to concentrate, cracks and the like are likely to occur in the insulating plate 12. For this reason, when a large external pressure is applied to the insulating plate 22 and a shock such as vibration is applied over a long period of time, cracks occur at the corners of the protrusion 22a and the flexible portion 22b. There has been a problem that it is difficult to accurately detect the external pressure over a long period of time.

  Further, when the ceramic green sheet for the protruding portion 22a and the ceramic green sheet for the flexible portion 22b are stacked, the ceramic green sheet for the flexible portion 22b forms the sealed space of the protruding portion 12a. It had the problem of being easily bent.

  In particular, when the thickness of the flexible portion 22b of the insulating plate 2 is reduced in order to detect the external pressure with high sensitivity, there is a problem that the above-described influence is likely to occur remarkably.

  The insulating plate 22 is formed of at least two layers of ceramic green sheets, ie, a ceramic green sheet for the protrusion 22a and a ceramic green sheet for the flexible portion 22b on which the second electrode 9 is formed. 12 has a problem that it is difficult to make the gap between the first electrode 27 and the second electrode 29 small and to have high sensitivity.

  Accordingly, the present invention has been devised in view of such conventional problems, and its purpose is to detect the external pressure accurately over a long period of time with a small size and high sensitivity for detecting the external pressure. It is an object of the present invention to provide a package for a pressure detection device that can perform the above.

  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 that is attached so as to face an electrode and is electrically connected to the other one of the wiring conductors; Has a recess formed in the main surface on the sealed space side, and a bottom plate portion of the recess Characterized in that between the side is a curved surface recessed.

  In the pressure detection device package according to the present invention, preferably, the insulating plate is made of ceramics, and the density of crystal grains in the bottom plate portion is larger than the density of crystal grains around the recess.

  The method for manufacturing a package for a pressure detection device according to the present invention is a method for manufacturing the package for a pressure detection device according to the present invention, wherein the ceramic green sheet serving as the insulating plate is pressed to form the recess in the ceramic green sheet. It has the process of forming, It is characterized by the above-mentioned.

  According to the pressure detection device package of the present invention, the insulating plate has a concave portion formed in the main surface on the sealed space side, and is a curved surface having a concave portion between the bottom plate portion and the inner side surface of the concave portion. When the bottom plate portion of the concave portion is bent, the stress applied to the corner portion between the bottom plate portion and the inner side surface of the concave portion is effectively dispersed to effectively prevent the stress from concentrating and Even when an impact such as vibration is applied over a long period of time with external pressure applied, it is possible to effectively prevent cracks from occurring at the corners between the bottom plate portion and the inner surface of the recess. Therefore, it is possible to provide a package for a pressure detection device that can accurately detect an external pressure over a long period of time.

  According to the pressure sensing device package of the present invention, the insulating plate is made of ceramics, and the density of crystal grains in the bottom plate portion of the recess is larger than the density of crystal grains around the recess. Strength can be improved and cracks can be more effectively prevented, and can be used as a pressure device detection device package used under a higher pressure atmosphere. Furthermore, when a sudden pressure change occurs, it is possible to effectively prevent the occurrence of cracks due to a sudden stress on the insulating plate.

Further, the hardness of the bottom plate portion of the concave portion can be increased, and the bottom plate portion of the concave portion is prevented from being deformed during the production of the pressure detecting device package, and is formed by the first electrode and the second electrode. The variation in capacitance can be suppressed. Further, the bottom plate portion can be made thin while maintaining sufficient strength of the bottom plate portion, and external pressure can be detected with high sensitivity. Moreover, it is possible to suppress a variation in detection of a pressure change due to deformation such as undulation of the bottom plate portion or vibration after bending with respect to a minute pressure change, and to achieve high accuracy.

  According to the method for manufacturing a package for a pressure detection device of the present invention, the method includes a step of pressing a ceramic green sheet serving as an insulating plate to form a recess in the ceramic green sheet. It is very easy to form a concave part with a curved surface between the inner surface and the inner surface, and the density of crystal grains in the bottom plate part can be made very easily from a single-layer ceramic green sheet more than the periphery of the concave part. Can be high. As a result, the density of the crystal grains changes in an inclined manner from the outer peripheral part of the bottom plate part of the concave part to the periphery of the concave part, and the stress due to the difference in thermal expansion between the high density part and the low density part of the crystal grain is well dispersed and insulated. It is possible to effectively prevent cracks in the plate.

  Moreover, since the variation in the density of the bottom plate portion can be suppressed and the variation in the deflection of the bottom plate portion when the pressure is applied can be suppressed, the external pressure can be detected with high sensitivity.

  In addition, since the concave portion is formed while applying pressure to the bottom plate portion of the concave portion by pressing, the bottom plate portion of the concave portion of the insulating plate does not bend and the insulating plate can be formed from a single-layer ceramic green sheet. Therefore, it is possible to provide a package for a pressure detection device that can be easily formed with a thin periphery of the recess, has a small interval between the first electrode and the second electrode, and can have high sensitivity.

  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, wherein 1 is an insulating substrate, 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 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, a suitable organic binder, solvent, plasticizer, and dispersant are added to and mixed with ceramic raw material powder such as aluminum oxide, silicon oxide, magnesium oxide, calcium oxide, etc. At the same time, a plurality of ceramic green sheets are obtained by forming the sheet into a sheet by employing a conventionally well-known doctor blade method, and then appropriately punching, laminating and cutting these ceramic green sheets. By processing, a green ceramic molded body for the insulating substrate 1 is obtained and the green ceramic molded body is heated to a temperature of about 1600 ° C. It is manufactured by firing at a degree.

  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 which is a part of the wiring conductor 5 is electrically connected to the first electrode 7. The conductive conductor 6 such as a solder bump is connected to the electrode of the semiconductor element 3 on the wiring conductor 5a. Thus, the electrode of the semiconductor element 3 and the first electrode 7 are electrically connected.

  Such a first electrode 7 is made of metal powder metallization of tungsten, molybdenum, copper, silver or the like having a thickness of about 10 to 50 μm, and an appropriate organic binder, solvent, plasticizer, or dispersant is applied to the metal powder such as tungsten. The metallized paste obtained by adding and mixing is printed on a ceramic green sheet for the insulating substrate 1 by employing a conventionally well-known screen printing method, and is fired together with the green ceramic molded body for the insulating substrate 1 to thereby insulate the insulating substrate. 1 is formed in a predetermined pattern in the central portion of the upper surface of 1. In addition, in order to prevent the first electrode 7 from being oxidatively corroded, a nickel plating layer having a thickness of about 1 to 10 μm is usually applied to the surface of the first electrode 7.

  Further, a frame-shaped first bonding metallization layer 8 is attached to the outer peripheral portion of the upper surface of the insulating substrate 1 over the entire circumference, and this first bonding metallization layer 8 is formed on the lower surface to be described later on the second electrode. 9 is bonded to the second bonding metallization layer 10 formed on the lower surface around the concave portion of the lower surface of the insulating plate 2 having 9 through the brazing material such as a silver-copper brazing material. A sealed space is formed in

  A wiring conductor 5b, which is one of the metallized wiring conductors 5, is connected to the first bonding metallization layer 8, and the electrodes of the semiconductor element 3 are connected to the wiring conductor 5b via electrical connection means such as solder bumps 6. When electrically connected, the electrode of the semiconductor element 3 and the second electrode 9 are electrically connected.

  Such a first bonding metallization layer 8 is made of metal powder metallization such as tungsten, molybdenum, copper, or silver, and an appropriate organic binder, solvent, plasticizer, or dispersant is added to and mixed with metal powder such as tungsten. The obtained metallized paste is printed and applied to a ceramic green sheet for the 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 obtain the outer periphery of the upper surface of the insulating substrate 1. A predetermined frame-like pattern is formed on the part. The first bonding metallization layer 8 is prevented from being oxidized and corroded on the surface of the first bonding metallization layer 8 and the bonding between the first bonding metallization layer 8 and the brazing material is strengthened. Further, usually, a nickel plating layer having a thickness of about 1 to 10 μm is applied.

  The insulating plate 2 bonded to the upper surface of the insulating substrate 1 is a rectangular or octagonal 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. Or it is flat form, such as circular shape, and has the recessed part whose depth is 0.01-5 mm in the center part. That is, the insulating plate 2 has a frame-shaped protrusion 2a having a height of 0.01 to 5 mm on the outer peripheral portion of the lower surface. The bottom plate portion 2b of the recess functions as a so-called pressure detection diaphragm that bends toward the insulating base 1 in response to an external pressure.

  In addition, since the mechanical strength of the insulating plate 2 tends to be small when the thickness of the bottom plate portion 2b of the recess is less than 0.01 mm, the insulating plate 2 is easily broken when a large external pressure is applied thereto. On the other hand, if the thickness of the bottom plate portion 2b exceeds 5 mm, the bottom plate portion 2b is difficult to be bent with a small pressure, and the accuracy as a pressure detecting diaphragm is likely to be lowered. Therefore, the thickness of the bottom plate portion 2b of the concave portion of the insulating plate 2 is preferably in the range of 0.01 to 5 mm.

  If such an insulating plate 2 is made of, for example, an aluminum oxide sintered body, a suitable organic binder, solvent, plasticizer, dispersion for ceramic raw material powder such as aluminum oxide, silicon oxide, magnesium oxide, calcium oxide, etc. A ceramic green sheet is obtained by adding a mixing agent to form a mud and forming it into a sheet using a conventionally known doctor blade method, and then punching or laminating the ceramic green sheet appropriately. The raw ceramic molded body for the insulating plate 2 is obtained by processing and cutting, and the raw ceramic molded body is manufactured by firing at a temperature of about 1600 ° C.

  A second electrode 9 for forming a capacitance facing the first electrode 7 is attached to the bottom surface of the insulating plate 2 on the bottom surface of the recess. The second electrode 9 is used to form a capacitance for the pressure sensitive element together with the first electrode 7 described above, and is formed in a circular pattern, for example.

  The second electrode 9 is made of metal powder metallization such as tungsten, molybdenum, copper, and silver having a thickness of about 10 to 50 μm, 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 plate 2 by employing a conventionally known screen printing method, and is fired together with the green ceramic molded body for the insulating plate 2 to synthesize the insulating plate. 2 is formed in a predetermined pattern at the center of the lower surface. The surface of the second electrode 9 is preferably coated with a nickel plating layer having a thickness of about 1 to 10 μm in order to prevent the second electrode 9 from being oxidized and corroded.

  Further, a circular or octagonal frame-shaped second bonding metallization layer 10 electrically connected to the second electrode 9 is attached to the lower surface of the protrusion 2 a of the insulating plate 2. The second bonding metallized layer 10 functions as a bonding base metal layer for bonding the insulating plate 2 to the insulating substrate 1, and the first bonding metallized layer 8 is silver-copper. The insulating base 1 and the insulating plate 2 are bonded together by bonding via a brazing material such as brazing, and the first bonding metallized layer 8 and the second bonding metallized layer 10 are electrically connected.

  At this time, the first electrode 7 and the second electrode 9 are opposed to each other with a sealed space formed between the insulating base 1 and the insulating plate 2 interposed therebetween. A predetermined capacitance is formed according to the area of the second electrode 9 and 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 bottom plate portion 2b of the concave portion of the insulating plate 2 is bent toward the insulating base 1 according to the pressure, and the distance between the first electrode 7 and the second electrode 9 is increased. As a result, the capacitance between the first electrode 7 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 electrostatic capacity is transmitted to the semiconductor element 3 accommodated in the recess 1a through the metallized wiring conductors 5a and 5b, and this is processed by the semiconductor element 3 so as to know the magnitude of the external pressure. be able to.

  Such a second bonding metallization layer 10 is made of a metal powder metallization such as tungsten, molybdenum, copper, or silver having a thickness of about 10 to 50 μm, and suitable organic binder, solvent, plasticizer, A metallized paste obtained by adding and mixing a dispersant is applied and applied to a ceramic green sheet for the insulating plate 2 using a conventionally known screen printing method, and is fired together with a green ceramic molded body for the insulating plate 2 Thus, a predetermined pattern is formed on the lower surface of the protrusion 2a of the insulating plate 2.

  In order to prevent the second bonding metallization layer 10 from being oxidatively corroded on the surface of the second bonding metallization layer 10 and to improve the bonding between the second bonding metallization layer 10 and the brazing material, A nickel plating layer having a thickness of about 1 to 10 μm is preferably applied.

  In addition, in order to bond the insulating plate 2 to the insulating substrate 1, a nickel plating layer having a thickness of about 1 to 10 μm is deposited in advance on the surfaces of the first bonding metallization layer 8 and the second bonding metallization layer 10, respectively. The insulating substrate 1 and the insulating plate 2 are sandwiched between a first bonding metallization layer 8 and a second bonding metallization layer 10 with a brazing filler metal foil having a thickness of about 10 to 200 μm. A method of brazing the metallized layer 8 for first bonding and the metallized layer 10 for second bonding by heating them to a temperature of about 850 ° C. in a reducing atmosphere to melt the brazing material foil is adopted. The

  The insulating plate 2 of the present invention has a concave portion formed in the main surface on the sealed space side, and is a curved surface having a concave portion between the bottom plate portion 2b and the inner side surface of the concave portion. When the 2b is bent, the stress applied to the corner portion between the bottom plate portion 2b of the recess and the inner side surface is effectively dispersed to effectively prevent the stress from being concentrated, and a large external pressure is applied to the insulating plate 2. Even when an impact such as vibration is applied over a long period of time in a state where is applied, cracks can be effectively prevented from occurring at the corners between the bottom plate 2b of the recess and the inner surface. Therefore, it is possible to provide a package for a pressure detection device that can accurately detect an external pressure over a long period of time.

  Preferably, the insulating plate 2 is made of ceramics, and the density of crystal grains in the bottom plate portion 2b of the recess is higher than the density of crystal grains around the recess. Thereby, the intensity | strength of the baseplate part of the insulating plate 2 improves, it can prevent more effectively that a crack generate | occur | produces, and it can be used as a package for pressure device detection apparatuses used under a higher pressure atmosphere. become. Furthermore, when a sudden pressure change occurs, it is possible to effectively prevent a crack from being generated due to a sudden stress generated in the insulating plate 2.

Further, the hardness of the bottom plate portion 2 of the concave portion can be increased, and the bottom plate portion 2 of the concave portion can be prevented from being deformed during the manufacture of the pressure detecting device package, and the first electrode 7 and the second electrode 9 In addition, the bottom plate can be made thin while maintaining sufficient strength of the bottom plate so that the external pressure can be detected with high sensitivity. Become. Moreover, it is possible to suppress a variation in detection of a pressure change due to deformation such as undulation of the bottom plate portion or vibration after bending with respect to a minute pressure change, and to achieve high accuracy.

  Next, the manufacturing method of the package for pressure detection apparatuses of this invention is demonstrated based on attached drawing. 2A to 2D are cross-sectional views for each process showing a manufacturing method for manufacturing the insulating plate 2 of the pressure detecting device package shown in FIG.

  First, as shown in FIG. 2A, a green sheet 11 for the insulating plate 2 is prepared. Such a green sheet 11 for the insulating plate 2 is suitable for ceramic raw material powders such as aluminum oxide, silicon oxide, calcium oxide, and magnesium oxide if the insulating substrate 1 is made of an aluminum oxide sintered body. It is manufactured by adding and mixing various organic binders and solvents, plasticizers, dispersants, etc. into a mud and adopting a sheet forming technique such as a known doctor blade method to form a sheet with a predetermined thickness. The

  Then, as shown in FIG. 2B, a conductive paste layer 12 serving as the second electrode 9 and the second bonding metallization layer is formed on the green sheet 11 for the insulating plate 2 by using a screen printing method or the like. The pattern is printed and applied. Next, the green sheet 11 for the insulating plate 2 is placed on the flat plate 13 (FIG. 2C), and is pressed with a mold 14 or the like, thereby forming a recess 15 for forming a sealed space. At the same time, the density of the bottom plate 2b of the recess 15 can be made higher than the periphery of the recess. Then, by performing cutting or the like, the generated shape of the insulating plate 2 is obtained, and the insulating plate 2 can be obtained by baking at a high temperature of about 1600 ° C. And the package for pressure detectors of this invention can be obtained by joining with the insulating board 1. FIG.

A dispensing device package can be provided.

  According to the method for manufacturing a package for a pressure detection device of the present invention, since the ceramic green sheet to be the insulating plate 2 is pressed to form a recess in the ceramic green sheet, the insulating plate 2 includes: A concave part having a curved surface between the bottom plate part 2b and the inner surface can be formed very easily and accurately, and the density of the crystal grains of the bottom plate part 2b can be easily reduced from a single-layer ceramic green sheet. Can be higher than the surroundings. As a result, the density of the crystal grains changes in an inclined manner from the outer peripheral part of the bottom plate part 2b of the concave part to the periphery of the concave part, and the stress due to the difference in thermal expansion between the high density part and the low density part of the crystal grain is well dispersed, It can prevent effectively that a crack arises in an insulating board.

  Moreover, since the variation in the density of the bottom plate portion can be suppressed and the variation in the deflection of the bottom plate portion when the pressure is applied can be suppressed, the external pressure can be detected with high sensitivity.

  In addition, since the concave portion is formed by applying pressure to the bottom plate portion 2b of the concave portion by pressing, the bottom plate portion 2b of the concave portion of the insulating plate 2 is not bent and an insulating plate is formed from a single-layer ceramic green sheet. It is possible to provide a package for a pressure detection device that can be easily formed with a thin periphery of a concave portion, the interval between the first electrode and the second electrode is small, and high sensitivity. Can do.

  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 the package of FIG. 3, pressing may be performed from both sides of the green sheet for the insulating plate 2 to form concave portions on the upper and lower surfaces. Thereby, when the baseplate part 2b of a recessed part bends, the load added between the baseplate part 2b of a recessed part and an internal peripheral surface can be reduced. In FIG. 1, the insulating substrate 1 and the insulating plate 2 are joined by a brazing material, but the green sheet for the insulating substrate 1 and the green sheet for the insulating plate 2 are laminated and then integrated by sintering. It does not matter if they are

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

It is sectional drawing which shows an example of embodiment of the package for pressure detection apparatuses of this invention. (A)-(d) is sectional drawing for every process for demonstrating the manufacturing method of the package for pressure detection apparatuses of this invention. It is sectional drawing which shows the other example of embodiment of the package for pressure detection apparatuses of this invention. 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 ················ Insulation plate 2b ··· ·················································· Semiconductor elements 5, 5a, 5b ... Wiring conductor ..... Second electrode

Claims (3)

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 insulating plate is formed on the main surface on the sealed space side. A recess is formed, and a curved surface is formed between the bottom plate portion and the inner surface of the recess. Package for pressure detection apparatus according to claim and. 2. The package for a pressure detection device according to claim 1, wherein the insulating plate is made of ceramics, and the density of crystal grains in the bottom plate portion is larger than the density of crystal grains around the recess. 3. The method for manufacturing a package for a pressure detecting device according to claim 2, further comprising a step of pressing the ceramic green sheet to be the insulating plate to form the recess in the ceramic green sheet. Manufacturing method for pressure detecting device package.

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