JP2006047326A - Package for pressure detector, and pressure detector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pressure detector for improving precision in pressure detection. <P>SOLUTION: The pressure detector comprises a ceramic substrate 1 that stores a semiconductor element 3 and has a recess 1a, in which a sealing material 4 made of resin is provided so that the semiconductor element 3 is covered; a wiring conductor 5a that passes through the ceramic substrate 1 and is formed so that it is led out to the recess 1a; a first electrode 7 that is formed on the surface of the ceramic substrate 1 and is connected to the wiring conductor 5a; a ceramic diaphragm 2 arranged on the ceramic substrate 1; and a second electrode 9 that is formed on the surface of the ceramic diaphragm 2 so as to face the first electrode 7. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a pressure detection device package 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. For example, as shown in a cross-sectional view in FIG. 4, the capacitance type pressure detection device is accommodated in a capacitance type pressure sensitive element 22 and a package 28 on a wiring board 21 made of a ceramic material or a resin material. And a semiconductor element 29 for operation. 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 in which one electrode 23 for forming a capacitance is attached at the center of the upper face, and an upper face of the insulating base 24 And an insulating plate 26 which is joined in a flexible state so as to form a sealed space with the insulating base 24, and the other electrode 25 for forming a capacitance is attached to the lower surface, and each capacitance It is composed of external lead terminals 27 for electrically connecting the forming electrodes 23 and 25 to the outside, and the insulating plate 26 bends in response to external pressure, thereby forming each capacitance. The capacitance formed between the electrodes 23 and 25 changes. Then, the external pressure can be detected by performing arithmetic processing on the change in the electrostatic capacitance by the semiconductor element 29 for arithmetic operation.

  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 becomes large and the pressure detection electrode 23 is increased. The wiring between 25 and the semiconductor element 29 becomes long, and an unnecessary electrostatic capacity is formed between the long wiring, so that the sensitivity is low.

  The present invention has been devised in view of such conventional problems, and an object of the present invention is to provide a pressure detection device that is small and has high sensitivity.

  According to the present invention, a semiconductor element is accommodated, and a ceramic base having a recess in which a resin sealing material is provided so as to cover the semiconductor element, and through the ceramic base and led to the recess The formed wiring conductor, the first electrode formed on the surface of the ceramic base and connected to the wiring conductor, the ceramic diaphragm disposed with respect to the ceramic base, and the surface of the ceramic diaphragm And a second electrode formed so as to face one electrode.

  The present invention includes a ceramic base having a recess provided with a resin sealing material so as to cover a semiconductor element, and a wiring conductor formed so as to penetrate the ceramic base and be led out to the recess. As a result, it is possible to improve the sealing performance of the space in which the capacitance is formed, and to improve the accuracy of pressure detection.

  Next, 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 detection device package according to the present invention, in which 1 is an insulating substrate, 2 is an insulating plate, and 3 is a semiconductor element.

  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 glass-ceramics. For example, in the case of an aluminum oxide sintered body, an appropriate organic binder, solvent, plasticizer, and dispersing agent are added to the ceramic raw material powder such as aluminum oxide, silicon oxide, magnesium oxide, and calcium oxide. Then, it is made into a mud shape and formed into a sheet shape by employing a conventionally known doctor blade method, and then a plurality of ceramic green sheets are obtained, and then appropriate punching and lamination are performed on these ceramic green sheets. By processing and cutting, a green ceramic molded body for the insulating substrate 1 is obtained and this green ceramic molded body is reduced to about 1 Manufactured by firing at a temperature of 600 ° C.

  The insulating base 1 is formed with a recess 1a for accommodating the semiconductor element 3 at the center of the lower surface thereof, thereby functioning as a container for accommodating the semiconductor element 3. The central portion of the bottom surface of the recess 1a is a mounting portion 1b on which the semiconductor element 3 is mounted. The semiconductor element 3 is mounted on the mounting portion 1b and the resin sealing such as an epoxy resin is provided in the recess 1a. The semiconductor element 3 is sealed by filling the material 4. In this example, the semiconductor element 3 is sealed by filling the recess 1a with a resin sealing material 4. However, the semiconductor element 3 has a lid made of metal or ceramics on the lower surface of the insulating base 1 to form the recess 1a. It may be sealed by bonding so as to block.

  Further, a plurality of metallized wiring conductors 5 connected to the respective electrodes of the semiconductor element 3 are led out to the mounting portion 1b, and the metalized wiring conductors 5 and the respective electrodes of the semiconductor element 3 are connected to conductive materials such as solder bumps 6 and the like. The electrodes of the semiconductor element 3 and the metallized wiring conductors 5 are electrically connected to each other through the conductive bonding member made of the semiconductor element 3 and the semiconductor element 3 is fixed to the mounting portion 1b. In this example, the electrode of the semiconductor element 3 and the metallized wiring conductor 5 are connected via the solder bumps 6. However, the electrode of the semiconductor element 3 and the metalized wiring conductor 5 are connected to other types of electric wires such as bonding wires. It may be connected by a general connection means.

  The metallized wiring conductor 5 functions as a conductive path for electrically connecting each electrode of the semiconductor element 3 to an external electric circuit and a first electrode 7 and a second electrode 9 to be described later. It leads to the outer peripheral lower 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 metallized wiring conductors 5 via the conductive bonding material 6 and the semiconductor element 3 is sealed with the resin sealing material 4. The part led out to the lower surface of the outer periphery of the insulating base 1 is joined to the wiring conductor of the external electric circuit board via a conductive bonding material such as solder, so that the semiconductor element 3 accommodated therein is electrically connected to the external electric circuit. Will be.

  Such a metallized wiring conductor 5 is made of metal powder metallization such as tungsten, molybdenum, copper, or silver, and is obtained by adding and mixing an appropriate organic binder, solvent, plasticizer, dispersant, or the like to metal powder such as tungsten. The metallized paste is printed and applied in a predetermined pattern on a ceramic green sheet for the insulating substrate 1 using a well-known screen printing method, and is fired together with a green ceramic molded body for the insulating substrate 1 to thereby form the insulating substrate 1. A predetermined pattern is formed inside and on the surface. In order to prevent the metallized wiring conductor 5 from being oxidized and corroded on the exposed surface of the metallized wiring conductor 5 and to improve the bonding between the metallized wiring conductor 5 and a conductive bonding material such as solder, If so, a nickel plating layer having a thickness of about 1 to 10 μm and a gold plating layer having a thickness of about 0.1 to 3 μm are sequentially deposited.

  Further, a frame-shaped protrusion 1c having a height of about 0.01 to 5 mm is provided on the outer peripheral portion of the upper surface of the insulating base 1, thereby forming a recess 1d having a substantially flat bottom surface at the center of the upper surface. As will be described later, the recess 1d is for forming a sealed space with the insulating plate 2, and a first electrode 7 for forming a capacitance is attached to the bottom surface of the recess 1d. Yes.

  The first electrode 7 is for forming a capacitance for a pressure sensitive element together with a second electrode 9 described later, and is formed in a substantially circular pattern, for example. The first electrode 7 is connected to one of the metallized wiring conductors 5a, whereby the electrode of the semiconductor element 3 is connected to the metallized wiring conductor 5a via a conductive bonding material such as a solder bump 6. Then, the electrode of the semiconductor element 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 together with a green ceramic molded body for the insulating substrate 1 to thereby form a predetermined surface on the bottom surface of the recess 1d of the insulating substrate 1. The pattern is formed. 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 exposed surface of the first electrode 7.

  Further, a frame-like bonding metallization layer 8 is deposited on the entire upper surface of the protruding portion 1c of the insulating substrate 1, and the bonding metallization layer 8 has an insulation having a second electrode 9 on the lower surface. The plate 2 is attached by bonding the second electrode 9 and the bonding metallization layer 8 via a conductive bonding material such as a silver-copper brazing material.

  One metal metallization wiring conductor 5b is connected to the metallization layer 8 for bonding, whereby the electrode of the semiconductor element 3 is electrically connected to the metallized wiring conductor 5b via a conductive bonding material such as a solder bump 6. As a result, the second electrode 9 connected to the bonding metallization layer 8 and the electrode of the semiconductor element 3 are electrically connected.

  The metallization layer 8 for bonding is made of metal powder metallization such as tungsten, molybdenum, copper, and silver. A screen printing method known in the art is used to print and apply to a ceramic green sheet for the insulating substrate 1, and this is fired together with a green ceramic molded body for the insulating substrate 1 to form a frame shape on the upper surface of the protrusion 1 c of the insulating substrate 1. Are formed in a predetermined pattern. In order to prevent the joining metallized layer 8 from being oxidized and corroded on the exposed surface of the joining metallized layer 8 and to strengthen the joining between the joining metallized layer 8 and the conductive joining material, If so, a nickel plating layer having a thickness of about 1 to 10 μm is applied.

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

  In addition, since the mechanical strength of the insulating plate 2 is less than 0.01 mm when the thickness is less, there is a greater risk of being destroyed when a large external pressure is applied thereto. On the other hand, when it exceeds 5 mm, it becomes difficult to bend at a small pressure, and it becomes unsuitable as a diaphragm for pressure detection. Therefore, the thickness 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 an agent and mixing it into a mud and forming it into a sheet using the well-known doctor blade method, and then punching or cutting the ceramic green sheet appropriately. The raw ceramic molded body for the insulating plate 2 is obtained by processing, and the raw ceramic molded body is manufactured by firing at a temperature of about 1600 ° C.

  Further, a second electrode 9 for forming a capacitance is deposited on substantially the entire lower surface of the insulating plate 2. The second electrode 9 functions as an electrode for forming a capacitance for a pressure sensitive element together with the first electrode 7 described above, and as a bonding base metal layer for bonding the insulating plate 2 to the insulating substrate 1. Function.

  The second electrode 9 is made of metal powder metallization such as tungsten, molybdenum, copper, or silver, and is obtained by adding and mixing an appropriate organic binder, solvent, plasticizer, or dispersant to metal powder such as tungsten. The paste is printed and applied to a ceramic green sheet for the insulating plate 2 using a well-known screen printing method, and is fired together with a green ceramic molded body for the insulating plate 2 so that the paste is applied to substantially the entire lower surface of the insulating plate 2. A predetermined pattern is formed. In order to prevent the second electrode 9 from being oxidatively corroded on the exposed surface of the second electrode 9 and to improve the bonding between the second electrode 9 and the conductive bonding material, the thickness is usually determined. Is coated with a nickel plating layer of about 1 to 10 μm.

  The second electrode 9 and the bonding metallization layer 8 are bonded via a conductive bonding material such as a silver-copper brazing material, whereby a sealed space is formed between the upper surface of the insulating substrate 1 and the lower surface of the insulating plate 2. Is formed and the metallization layer 8 for bonding and the second electrode 9 are electrically connected.

  At this time, the first electrode 7 and the second electrode 9 are opposed to each other with a 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 two electrodes 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 insulating plate 2 bends toward the insulating base 1 in accordance with the pressure, and the interval between the first electrode 7 and the second electrode 9 changes. Since the capacitance between the first 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 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.

  Thus, according to the package for a pressure detection device of the present invention, the first electrode 7 for forming a capacitance is provided on the other main surface of the insulating base 1 on which the semiconductor element 3 is mounted on one main surface. At the same time, the insulating plate 2 having the second electrode 9 for forming capacitance facing the first electrode 7 on the inner surface is joined in a flexible state so as to form a sealed space between the insulating base 1 and the insulating plate 2. Therefore, the container for housing the semiconductor element 3 and the pressure sensitive element are integrated, and as a result, the pressure detection device can be miniaturized. Further, since the first electrode 7 and the second electrode 9 for forming the capacitance are connected to the semiconductor element 3 through the metallized wiring conductors 5a and 5b provided on the insulating base 1, the first electrode 7 and the second electrode 9 are formed. The electrode 9 can be connected to the semiconductor element 3 at a short distance, and as a result, a highly sensitive pressure detecting device is provided by reducing unnecessary capacitance generated between the metallized wiring conductors 5a and 5b. Can do.

  In addition, when the space | interval of the 1st electrode 7 and the 2nd electrode 9 is less than 0.01 mm in 1 atmosphere, when a big pressure is applied to the insulating board 2, the 1st electrode 7 and the 2nd electrode 9 will contact. On the other hand, if the pressure exceeds 5 mm, the capacitance formed between the first electrode 7 and the second electrode 9 becomes small, and the pressure is reduced. The detection sensitivity tends to be low. Therefore, the distance between the first electrode 7 and the second electrode 9 is preferably in the range of 0.01 to 5 mm in 1 atmosphere.

  Thus, according to the above-described package for a pressure detection device, the semiconductor element 3 is mounted on the mounting portion 1a, and each electrode of the semiconductor element 3 and the metallized wiring conductor 5 are electrically connected. By sealing, it becomes a small and highly sensitive pressure detection device.

  Note that the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the gist of the present invention. For example, in the above-described embodiment, a frame-shaped protrusion 1c is provided on the outer peripheral portion of the upper surface of the insulating base 1, and the insulating plate 2 is joined to the protrusion 1c, whereby the upper surface of the insulating base 1 and the insulating plate 2 are connected. However, according to the present invention, as shown in a cross-sectional view in FIG. 2, a frame-like protrusion 2 a is provided on the outer periphery of the lower surface of the insulating plate 2, and this is joined to the upper surface of the insulating substrate 1. Thus, a sealed space may be provided between the insulating base 1 and the insulating plate 2. In this case, a metallizing layer 10 for bonding may be provided on the lower surface of the protrusion 2a, and the metallizing layer 10 for bonding may be bonded to the metallizing layer 8 for bonding via a conductive bonding material such as silver-copper solder. The joining metallized layer 10 and the second electrode layer 9 may be electrically connected by providing the insulating plate 2 with a connecting metallized conductor 11 for connecting them.

  Further, according to the present invention, as shown in a cross-sectional view in FIG. 3, a metal frame 12 made of, for example, iron-nickel-cobalt alloy or iron-nickel alloy is provided on the outer periphery of the upper surface of the insulating base 1 such as silver-copper solder. The insulating plate 2 is bonded between the insulating substrate 1 and the insulating plate 2 by bonding the insulating plate 2 to the metal frame 12 via a conductive bonding material such as silver-copper solder. A sealed space may be provided.

It is sectional drawing which shows an example of embodiment 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 which shows the further another example of embodiment of the package for pressure detection apparatuses of this invention. It is sectional drawing which shows the conventional pressure detection apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Insulation base | substrate 2 ... Diaphragm 3 ... Semiconductor element 5, 5a, 5b ... Wiring conductor 7 ... First electrode 9 ... Second electrode

Claims (4)

A ceramic substrate having a recess in which a semiconductor element is accommodated and a resin sealing material is provided so as to cover the semiconductor element;
A wiring conductor formed so as to penetrate the ceramic base and to be led to the recess;
A first electrode formed on the surface of the ceramic base and connected to the wiring conductor;
A ceramic diaphragm disposed against the ceramic substrate;
A package for a pressure detection device, comprising a second electrode formed on the surface of the ceramic diaphragm so as to face the first electrode. 2. The pressure detection device according to claim 1, wherein another wiring conductor electrically connected to the semiconductor element is formed inside the ceramic base so as to be led out around the recess. For package. A ceramic substrate having a recess;
A wiring conductor formed so as to penetrate the ceramic base and to be led to the recess;
A first electrode formed on the surface of the ceramic base and connected to the wiring conductor;
A ceramic diaphragm disposed against the ceramic substrate;
A second electrode formed on the surface of the ceramic diaphragm so as to face the first electrode;
A semiconductor element housed in the recess of the ceramic substrate and electrically connected to the wiring conductor;
A pressure detection device comprising: a resin sealing material provided in the concave portion of the ceramic base so as to cover the semiconductor element. The pressure detecting device according to claim 3, wherein the recess is formed in the ceramic base so as to face a space formed by the ceramic base and the ceramic diaphragm.

Images