JP2005214735A - Package for pressure detecting apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a compact and highly reliable package for pressure detecting apparatus capable of accurately detecting pressure exerted from the outside with high sensitivity for a long period of time. <P>SOLUTION: The package for pressure detecting device is provided with an insulating substrate 1 having a mounting part 1a for mounting a semiconductor element 3 to a side surface, a plurality of wiring conductors 5 arranged in the surface and inside of the insulating substrate 1 and electrically connected to electrodes of the semiconductor element 3, an insulating plate 2 joined to the insulating substrate 1 in such a flexible state as to form a sealed space in between with one main surface of the insulating substrate 1, a first electrode 7 for forming electrostatic capacitance deposited to the one main surface of the insulating substrate 1 in the sealed space and electrically connected to one of the wiring conductors 5, and a second electrode 9 for forming electrostatic capacitance deposited to an inside main surface the insulating plate 2 in such a way as to be opposed to the first electrode 7 and electrically connected to another one of the wiring conductors 5. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

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

  Conventionally, a capacitance type pressure detection device is known as a pressure detection device for detecting pressure. As shown in a cross-sectional view in FIG. 3, this capacitance type pressure detection device has a capacitance type pressure sensitive element 22 and a pressure detection device package on a wiring board 21 made of a ceramic material or a resin material. 28 and a semiconductor element 29 for calculation contained in 28.

  The pressure sensitive element 22 is made of, for example, an electrically insulating material such as a ceramic material, and has an insulating base 24 having a concave portion with a capacitance forming electrode 23 attached to the center of the upper surface thereof. An insulating plate 26 is bonded to the upper surface in a flexible state so that the concave portion of the insulating base 24 becomes a sealed space, and an electrostatic capacitance forming electrode 25 is attached to the main surface on the sealed space side. Each of the capacitance forming electrode 23 and the electrode 25 is composed of an external lead terminal 27 for electrically connecting to the outside. As a result, the capacitance formed between the electrode 23 and the electrode 25 is changed by bending the insulating plate 26 according to the pressure applied from the outside, and this change is calculated by the semiconductor element 29 for calculation. By doing so, the pressure applied from the outside can be detected.

  However, according to this conventional pressure detection device, since the pressure sensitive element 22 and the semiconductor element 29 are individually mounted on the wiring board 21, the pressure detection device is enlarged and the pressure detection electrode 23 and The wiring conductor that connects the electrode 25 and the semiconductor element 29 becomes long, and there is a problem that sensitivity is lowered because unnecessary capacitance is generated.

  Therefore, as shown in a cross-sectional view in FIG. 2, an insulating base 11 having a mounting portion 11 a on which the semiconductor element 13 is mounted on one main surface, and the surface and inside of the insulating base 11 are provided. A plurality of wiring conductors 15 that are electrically connected to each other and a central portion of the other main surface of the insulating base 11 are attached to the wiring conductor 15a that is one of the wiring conductors 15 and electrically connected to the wiring conductor 15a. Insulating plate joined in a flexible state so as to form a sealed space between the first electrode 17 for forming capacitance and the other main surface of the insulating substrate 11 and the central portion of the main surface. 12 is formed on the inner surface of the insulating plate 12 so as to face the first electrode 17 and is electrically connected to a wiring conductor 15b, which is another wiring conductor 15. A pressure sensing device package comprising a second electrode 19 is proposed. And are (for example, see Patent Document 1 below).

  According to this pressure detection device package, since the pressure sensitive element is integrally formed in the pressure detection device package that accommodates the semiconductor element 13, the pressure detection device can be reduced in size and the pressure detection electrode and The wiring conductor 15 connecting the semiconductor element 13 can be shortened, and unnecessary capacitance generated between the plurality of wiring conductors 15 can be reduced.

  Conventionally, the wiring conductor 15 of the pressure detection device package, the first electrode 17 for forming capacitance, and the second electrode 19 are made of tungsten (W), molybdenum (Mo), copper (Cu), silver (Ag), or the like. A ceramic green sheet (hereinafter referred to as a green sheet) made of a metal powder metallized and obtained by adding a suitable organic binder, a solvent, a plasticizer and a dispersing agent to a metal powder such as W and mixing them by a conventionally known screen printing method. Also, it is manufactured by printing and coating them together with a green ceramic molded body in which green sheets to be the insulating base 11 and the insulating plate 12 are stacked one above the other.

  Further, in order to use the first electrode 17 and the second electrode 19 for forming a capacitance, it is necessary to form a certain space region between the first electrode 17 and the second electrode 19. Alternatively, by forming the frame-shaped protrusion 12 a on the outer peripheral portion of the insulating plate 12, a sealed space for forming a capacitance is formed between the insulating base 11 and the insulating plate 12.

  The insulating substrate 11 and the insulating plate 12 are a first bonding metallization layer 18 provided around the first electrode 17 on the insulating substrate 11 and a second bonding material provided on the outer periphery of the insulating plate 12. The metallized layer 20 is attached by bonding with a conductive bonding material such as a brazing material.

In addition, the insulating plate 12 having such a protruding portion 12a is formed with the green sheet for the protruding portion 12a in which a through hole for forming a sealed space is formed by a punching method or the like, and the second electrode 19. It is formed by laminating a green sheet for the bottom plate portion 12b to form a green sheet for the insulating plate 12 and firing at a high temperature.
JP 2001-356064 A

  However, according to the conventional package for a pressure detection device, the wiring conductor 15 a connected to the first electrode 17 and the wiring conductor 15 b connected to the second electrode 19 are formed between the first electrode 17 and the second electrode 19. The capacitance of the wiring conductor 15 a connected to the first electrode 17 and a part of the wiring conductor 15 b connected to the second electrode 19 are not connected to the first electrode 17 and the second electrode 19. It is disposed at the position where it is vertically overlapped, and unnecessary capacitance is formed between the wiring conductors 15a, 15b and the first electrode 17 and the second electrode 19, so that the pressure detection sensitivity decreases. Had problems.

  Also, unnecessary capacitance is formed between the wiring conductor 15a connected to the first electrode 17 and the wiring conductor 15b connected to the second electrode 19, and a more sensitive pressure detecting device can be obtained. It had the problem of being difficult.

Therefore, the present invention has been devised in view of the above-mentioned requirements, and the purpose thereof is small and has high detection sensitivity of pressure applied from the outside, and can be accurately detected over a long period of time. The object is to provide a package for a pressure sensing device.

  A package for a pressure detection device according to the present invention is provided on an insulating base having a mounting portion on which a semiconductor element is mounted on a side surface, and on the surface and inside of the insulating base, and the electrodes of the semiconductor element are electrically connected to each other. An insulating plate joined to the insulating base in a flexible state so as to form a sealed space between the plurality of wiring conductors and one main surface of the insulating base; and the insulating base in the sealed space A first electrode for forming a capacitance that is attached to one main surface and is electrically connected to one of the wiring conductors, and to face the first electrode on the inner main surface of the insulating plate And a second electrode for forming a capacitance, which is applied and electrically connected to the other one of the wiring conductors.

  According to the pressure detection device package of the present invention, since the semiconductor element is mounted on the mounting portion on the side surface of the insulating base, the wiring conductor connected to the first electrode electrically connected to the electrode of the semiconductor element, and The wiring conductor connected to the second electrode can be disposed only on the side and outer periphery of the insulating base that does not overlap the first electrode and the second electrode. As a result, the wiring conductor and the second electrode It is possible to effectively prevent unnecessary capacitance from being formed between the one electrode and the second electrode.

  Further, the wiring conductor connected to the first electrode and the wiring conductor connected to the second electrode can be arranged as extremely short, and as a result, unnecessary capacitance is formed between the wiring conductors. This can be effectively prevented.

  Accordingly, it is possible to provide a highly reliable package for a pressure detection device that is small in size and has high detection sensitivity of pressure applied from the outside, and can be accurately detected over a long period of time.

  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 and insulating plate 2 of the present invention are made of an aluminum oxide sintered body, an aluminum nitride sintered body, a mullite sintered body, a silicon carbide sintered body, a silicon nitride sintered body, a glass ceramic, or the like. Made of electrically insulating material. If the insulating base 1 and the insulating plate 2 are made of, for example, an aluminum oxide sintered body, a suitable organic binder, solvent, plastics for ceramic raw material powders such as aluminum oxide, silicon oxide, magnesium oxide, and calcium oxide are used. Add and mix the agent and dispersant to form a slurry, and form this into a sheet by a conventionally known doctor blade method or the like to obtain a plurality of green sheets. It is manufactured by punching, laminating, cutting and the like and laminating it vertically to form a green ceramic molded body, which is fired at a temperature of about 1600 ° C.

  The insulating substrate 1 has a mounting portion 1a for mounting the semiconductor element 3 on the side surface. The semiconductor element 3 is sealed by being mounted on the mounting portion 1a and being covered with a resin sealing material 4 such as an epoxy resin.

  In addition, a plurality of wiring conductors 5 are led out to the mounting portion 1a, and the wiring conductor 5 and each electrode of the semiconductor element 3 are joined via a conductive joining material 6 such as a solder bump, so that the semiconductor element 3 is connected. Each electrode and each wiring conductor 5 are electrically connected, and the semiconductor element 3 is attached to the mounting portion 1a. Alternatively, the semiconductor element 3 may be connected to the wiring conductor 5 by other electrical connection means such as a bonding wire.

  The wiring conductor 5 functions as a conductive path for electrically connecting each electrode of the semiconductor element 3 to the external electric circuit, 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 (the lower surface in FIG. 1), and another part is electrically connected to the first electrode 7 and the second electrode 9.

  Such a wiring conductor 5 is made of metal powder metallization such as W, Mo, Cu, and Ag, and is obtained by adding and mixing an appropriate organic binder, solvent, plasticizer, dispersant, and the like to metal powder such as W. The paste is printed and applied in a predetermined pattern on a green sheet for the insulating substrate 1 by a well-known screen printing method, and this is baked together with a green ceramic molded body for the insulating substrate 1, thereby predetermining the inside and the surface of the insulating substrate 1. The pattern is formed. 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.

  A first electrode 7 for forming a capacitance is attached to the center of the other main surface (upper surface in FIG. 1) of the insulating substrate 1, and this first electrode 7 is a part of the wiring conductor 5. Is electrically connected to the wiring conductor 5a. The first electrode 7 and the electrode of the semiconductor element 3 are electrically connected by connecting the electrode of the semiconductor element 3 to the wiring conductor 5a via the conductive bonding material 6 such as a solder bump. The first electrode 7 is formed in a circular shape, for example.

  Further, a frame-shaped first bonding metallization layer 8 is deposited on the outer peripheral portion of the other main surface of the insulating base 1 over the entire periphery, and the insulating plate 2 having the metallized layer 8 and a concave portion to be described later. A sealed space is formed between the insulating base 1 and the insulating plate 2 by bonding the second bonding metallization layer 10 via a brazing material such as an Ag—Cu brazing material.

  The first bonding metallized layer 8 is electrically connected to a wiring conductor 5b, which is one of the metallized wiring conductors 5. The conductive bonding material 6 such as a solder bump is connected to the electrode of the semiconductor element 3 on the wiring conductor 5b. The electrode of the semiconductor element 3 and the second electrode 9 are electrically connected by being electrically connected via.

  The insulating plate 2 has a rectangular shape, a polygonal shape such as an octagonal shape, or a flat plate shape such as a circular shape, and a frame-shaped protruding portion 2a having a height of 0.01 to 5 mm is formed on the outer peripheral portion of one main surface. Thus, a recess is formed. And the baseplate part 2b which is a site | part which comprises the bottom face of the recessed part of the insulation board 2 bends to the insulation base | substrate 1 side according to the pressure added from the outside, and functions as a so-called pressure detection diaphragm.

  The insulating plate 2 has a low mechanical strength when the thickness of the bottom plate portion 2b is less than 0.01 mm, and is easily broken when the pressure applied from the outside is large. Further, if the thickness of the bottom plate portion 2b exceeds 5 mm, the bottom plate portion 2b is difficult to bend when the pressure applied from the outside is small, 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.

It is preferable that the ratio between the thickness (mm) of the insulating plate 2 and the area (mm ² ) of the bottom plate portion 2b of the concave portion forming the sealed space is 5 to 500. If it is less than 10, the insulating plate 2 is difficult to bend and the area of the second electrode 9 is also reduced, and the pressure detection sensitivity is likely to be lowered. If it exceeds 500, the insulating substrate 1 and the insulating plate 2 become large and the package becomes easy to enlarge, and the first electrode 7 and the second electrode 9 come into contact with each other due to the bending of the insulating plate 2 due to its own weight. It becomes easy and cannot be detected with high accuracy, or the strength of the insulating plate 2 is lowered and easily damaged.

  A second electrode 9 for forming a capacitance is attached to the bottom surface of the recess of the insulating plate 2. The second electrode 9 is formed in a circular shape, for example, and forms a capacitance for the pressure sensitive element so as to face the first electrode 7 described above.

  The first electrode 7 and the second electrode 9 as described above are made of metal powder metallization such as W, Mo, Cu, and Ag having a thickness of about 10 to 50 μm, and are formed by the same method as the wiring conductor 5. Further, a nickel plating layer having a thickness of about 1 to 10 μm is preferably deposited on the surfaces of the first electrode 7 and the second electrode 9 in order to prevent oxidative corrosion.

  Further, a polygonal or circular frame-shaped second bonding metallization layer 10 electrically connected to the second electrode 9 is attached to the main surface of the protrusion 2a of the insulating plate 2 on the insulating base 1 side. ing. The second bonding metallization layer 10 functions as a bonding base metal layer for bonding the insulating plate 2 to the insulating substrate 1, and the second bonding metallization layer 10 and the first bonding metallization layer 8 are made of Ag-. The first metallization layer 8 for bonding and the second metallization layer 10 for bonding are electrically connected through a brazing filler metal such as Cu brazing.

  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, and the first electrode 7 and the second electrode 9 are interposed between the electrodes. A predetermined capacitance is formed according to the area of the first electrode 7 and the distance between the first electrode 7 and the second electrode 9. Then, the bottom plate portion 2b of the insulating plate 2 bends toward the insulating base 1 according to the pressure applied to the other main surface of the insulating plate 2 from the outside, and the distance between the first electrode 7 and the second electrode 9 changes. By changing the capacitance, it functions as a pressure-sensitive element that senses a change in pressure applied from the outside as a change in capacitance. Further, the change in capacitance is transmitted to the semiconductor element 3 mounted on the side surface of the insulating substrate 1 through the metallized wiring conductors 5a and 5b, and the magnitude of the pressure applied from the outside by performing arithmetic processing in the semiconductor element 3 Can know.

  The first bonding metallization layer 8 and the second bonding metallization layer 10 are made of metal powder metallization such as W, Mo, Cu, and Ag having a thickness of about 10 to 50 μm, and are similar to the wiring conductor 5 described above. It is formed by the method. It should be noted that the surfaces of the first bonding metallization layer 8 and the second bonding metallization layer 10 are prevented from being oxidized and corroded, and the first bonding metallization layer 8 and the second bonding metallization layer 10 are bonded to the brazing material. In order to strengthen the thickness, a nickel plating layer having a thickness of about 1 to 10 μm is preferably applied.

  In addition, in the bonding of the insulating substrate 1 and the insulating plate 2, a nickel plating layer having a thickness of about 1 to 10 μm is previously deposited on the surfaces of the first bonding metallization layer 8 and the second bonding metallization layer 10, respectively. In addition, a brazing material foil made of Ag—Cu brazing having a thickness of about 10 to 200 μm is sandwiched between the first bonding metallization layer 8 and the second bonding metallization layer 10, and these are about 850 ° C. in a reducing atmosphere. This is performed by melting the brazing material foil by heating to a temperature of 1 mm and brazing the metallized layer 8 for first bonding and the metallized layer 10 for second bonding.

  And in this invention, although the semiconductor element 3 is mounted in the mounting part 1a of the side surface of the insulation base | substrate 1, that is important. Thus, since the semiconductor element 3 is mounted on the mounting portion 1a on the side surface of the insulating base 1, the wiring conductor 5a connected to the first electrode 7 electrically connected to the electrode of the semiconductor element 3 and the second The wiring conductor 5b connected to the electrode 9 can be disposed only on the side surface and the outer periphery of the insulating base 1 that does not overlap the first electrode 7 and the second electrode 9, and as a result, It is possible to effectively prevent unnecessary capacitance from being formed between the wiring conductors 5 a and 5 b and the first electrode 7 and the second electrode 9.

  Further, the wiring conductor 5a connected to the first electrode 7 and the wiring conductor 5b connected to the second electrode 9 can be arranged as extremely short, and as a result, between the wiring conductors 5a and 5b. It is possible to effectively prevent unnecessary capacitance from being formed.

  Thus, according to the package for a pressure detection device of the present invention, the first electrode 7 for forming a capacitance is covered on the other main surface of the insulating base 1 on which the semiconductor element 3 is mounted on the side mounting portion 1a. The first electrode 7 is opposed to the inner main 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. Since the deposited 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 the pressure detecting device can be miniaturized.

  Further, the wiring conductor 5a connected to the first electrode 7 electrically connected to the electrode of the semiconductor element 3 mounted on the mounting portion 1a on the side surface of the insulating base 1 and the wiring conductor 5b connected to the second electrode 9 Can be arranged so as not to overlap with the first electrode 7 and the second electrode 9 between the wiring conductors 5a, 5b and the first electrode 7 and the second electrode 9. It is possible to effectively prevent the formation of unnecessary capacitance, and the wiring conductor 5a connected to the first electrode 7 and the wiring conductor 5b connected to the second electrode 9 are arranged as extremely short ones. Therefore, it is possible to effectively prevent unnecessary capacitance from being formed in the wiring conductors 5a and 5b. As a result, it is possible to provide a highly reliable package for a pressure detection device that has high detection sensitivity of pressure applied from the outside and can accurately detect over a long period of time.

  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, in FIG. 1, the insulating substrate 1 and the insulating plate 2 are bonded together by a conductive bonding material. After the green sheet for the insulating substrate 1 and the green sheet for the insulating plate 2 are laminated, sintering is performed. It may be integrated.

  Further, the concave portion and the protrusion 2 a of the insulating plate 2 for providing a sealed space for forming a capacitance may be provided on the other main surface of the insulating base 1.

  Furthermore, the semiconductor element 3 mounted on the mounting portion 1a on the side surface of the insulating substrate 1 may be formed with a recess formed on the side surface of the insulating substrate 1 and housed in this recess.

  Similarly, the second insulating plate is joined in a flexible state on the other main surface opposite to one main surface of the insulating substrate 1 to which the insulating plate 2 is bonded, thereby forming a second sealed space. The third electrode may be formed on the other main surface of the insulating base 1 in the second sealed space and the fourth electrode may be formed on the inner main surface of the second insulating plate to form the second capacitor portion. . As a result, when a centrifugal force is applied, the upper and lower insulating plates of the insulating substrate 1 bend in the same direction, whereas with respect to the pressure change, the centrifugal force and the pressure change are caused by bending in the opposite direction. The discrimination becomes easy and the accuracy of pressure detection can be further improved.

  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. It is sectional drawing of the conventional package for pressure detection apparatuses. It is sectional drawing of the conventional pressure detection apparatus.

Explanation of symbols

1 ········ Insulation base 1a ····· Mounting portion 2 ············· Insulation plate 2b ··· ················································· Semiconductor element 5, 5a, 5b ··· Wiring conductor ..... Second electrode

Claims (1)

An insulating base having a mounting portion on which a semiconductor element is mounted on a side surface; a plurality of wiring conductors disposed on and in the surface of the insulating base and electrically connected to electrodes of the semiconductor element; and An insulating plate bonded to the insulating base in a flexible state so as to form a sealed space between the main surface and the one main surface of the insulating base in the sealed space; A first electrode for forming a capacitance electrically connected to one of the wiring conductors, and attached to the inner main surface of the insulating plate so as to face the first electrode; A package for a pressure detection device, comprising: a second electrode for forming a capacitance electrically connected to one.

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