JP2015007573A - Pressure detection device base substance and pressure detection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pressure detection device base substance capable of detecting an external pressure with high accuracy, and a pressure detection device.SOLUTION: A pressure detection device base substance according to the present invention comprises an internal space 14, an insulation base substance 1 having a top surface provided in parallel with the internal space 14 in a plan view and including an electronic component mounting part and a flexible part provided adjacent thereto on the internal space 14, a plurality of electrodes 2 provided on the inner surface of the internal space 14 or inside the insulation base substance 1 so as to sandwich the internal space 14, and an external terminal 4 provided on the underside of the insulation base substance 1, the height of the electronic component mounting part being located at a height equal to or below the bottom edge of the internal space 14.

Description

  The present invention relates to a capacitance type pressure sensing device substrate and a pressure sensing device for detecting pressure.

  Conventionally, a capacitance type pressure detection device is used as a pressure detection device for detecting pressure. As a base for a pressure detection device used in this capacitance type pressure detection device, a predetermined space is provided between the insulating substrate having a first electrode for forming a capacitance on the surface and the insulating substrate. A diaphragm having a second electrode for forming a capacitance that is flexibly bonded to the surface of the insulating substrate and is opposed to the first electrode; and between the insulating substrate and the diaphragm One having a spacer provided is known. In such a pressure detection device substrate, an insulating substrate, a diaphragm, and a spacer are integrally formed, and thereby an internal space sealed by the insulating substrate is formed. In such a pressure detection device, when the diaphragm bends due to an external pressure fluctuation, the distance between the first electrode and the second electrode changes and the capacitance between them changes. The pressure fluctuation can be detected by the change of.

  In such a pressure detection device, an electronic component for calculating a change in capacitance may be mounted around the inner space of the insulating base of the pressure detection device base (for example, Patent Documents). 1).

Japanese Patent Laid-Open No. 2005-214736

  However, when the heat generated from the electronic component is transmitted to the diaphragm and the diaphragm is deformed into a concave shape or a convex shape, the distance between the insulating substrate and the diaphragm changes, and the distance between the first electrode and the second electrode Since the capacitance formed between the two changes, there is a concern that the external pressure cannot be accurately detected.

  A base for a pressure detection device according to an aspect of the present invention is provided adjacent to an internal space, an upper surface including an electronic component mounting portion provided adjacent to the internal space in plan view, and the internal space. An insulating base having a flexible portion; a plurality of electrodes provided on the inner surface of the internal space or inside the insulating base so as to sandwich the internal space; and an external terminal provided on the lower surface of the insulating base; The electronic component mounting part is located below the internal space.

  A pressure detection device according to another aspect of the present invention includes a pressure detection device base and an electronic component mounted on the electronic component mounting portion of the pressure detection device base.

  In the base for a pressure detection device according to one aspect of the present invention, since the electronic component mounting portion is positioned below the internal space, the heat generated from the electronic component mounted on the electronic component mounting portion is transferred to the flexible portion. The external pressure can be detected with high accuracy by reducing the deformation of the flexible portion due to thermal stress and suppressing the change in capacitance.

  The pressure detection device according to another aspect of the present invention includes a pressure detection device base and an electronic component mounted on the electronic component mounting portion of the pressure detection device base, and thus detects external pressure with high accuracy. It can be set as the pressure detection apparatus which can.

(A) is a top view in the pressure detection apparatus in the 1st Embodiment of this invention, (b) is a bottom view of (a). It is sectional drawing in the AA line of Fig.1 (a). (A) is a top view in the pressure detection apparatus in the 2nd Embodiment of this invention, (b) is a bottom view of (a). (A) is sectional drawing in the AA line of Fig.3 (a), (b) is sectional drawing in the BB line of Fig.3 (a). It is sectional drawing in the pressure detection apparatus in the 3rd Embodiment of this invention. (A) is a top view in the pressure detection apparatus in the other example of the 1st Embodiment of this invention, (b) is a bottom view of (a). It is sectional drawing in the AA line of Fig.6 (a).

  Several exemplary embodiments of the present invention will be described with reference to the accompanying drawings.

(First embodiment)
As in the example shown in FIGS. 1 and 2, in the pressure detection device according to the first embodiment of the present invention, the insulating base 1 includes a base portion 11 and a frame portion 12 provided on the base portion 11, And a flexible portion 13 provided above the base portion 11 and inside the frame portion 12. The insulating base 1 has an internal space 14 surrounded by a base part 11, a frame part 12, and a flexible part 13. The flexible portion 13 is provided adjacent to the internal space 14. A plurality of electrodes 2 are provided so as to sandwich the internal space 14. A wiring conductor 3 is provided on the surface and inside of the insulating substrate 1, and an external terminal 4 is provided on the lower surface of the insulating substrate 1. On the upper surface of the insulating base 1, a recess 15 is provided in line with the internal space 14 and provided with an electronic component mounting portion. The height of the electronic component mounting portion is the height of the lower end of the internal space 14. Located in: 1 and 2, the electronic device is provided in a virtual xyz space, and for the sake of convenience, “upward” refers to the positive direction of the virtual z axis.

  The insulating base 1 is formed in a square shape in plan view, and the inner diameter and the flexible portion 13 of the frame portion 12 and the internal space 14 are formed in a circular shape in plan view.

  The insulating substrate 1 is an electrically insulating sintered body 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, as in the example shown in FIG. 1, the internal space 14 is formed by laminating a plurality of insulating layers.

If the insulating base 1 is made of, for example, an aluminum oxide sintered body, it is manufactured as follows. First, a ceramic raw material powder such as aluminum oxide, silicon oxide, magnesium oxide, and calcium oxide is mixed with a suitable organic binder, solvent, plasticizer, and dispersant to form a slurry, and this is formed into a sheet by the doctor blade method. To obtain a plurality of ceramic green sheets. A ceramic green sheet for the insulating substrate 1 is obtained by subjecting these ceramic green sheets to appropriate punching and cutting. At this time, in some of the ceramic green sheets for the frame portion 12, through holes serving as the internal space 14 are formed by a hole processing method such as punching by a die or punching or laser processing. By laminating these ceramic green sheets, a ceramic green sheet laminate for the insulating substrate 1 having the internal space 14 is formed. Then, by firing this ceramic green sheet laminate at a temperature of about 1600 ° C., the insulating base 1 having the internal space 14 surrounded by the base part 11, the frame part 12 and the flexible part 13 is manufactured.

  Further, in the example shown in FIG. 1, an electronic component mounting portion on which the electronic component 5 is mounted is provided on the bottom surface of the concave portion 15 provided side by side in the internal space 14. The height of the bottom surface of the recess 15 provided with the electronic component mounting portion is positioned below the height of the lower end of the internal space 14. In the example shown in FIG. 1, the bottom surface of the recess 15 is the same height as the lower end of the internal space 14, but below the lower end of the internal space 14 as in the example shown in FIG. 7 described later. If it is positioned, the heat generated from the electronic component 5 mounted on the electronic component mounting portion is more easily transmitted downward, which is preferable because it is less likely to be transmitted to the flexible portion. Such recesses 15 are formed by forming through holes to be the recesses 15 in some of the ceramic green sheets for the insulating substrate 1 by a hole processing method such as punching by a die or punching or laser processing. It is formed.

  Electrodes 2 facing each other are formed on the lower surface of the flexible portion 13 and the upper surface of the base portion 11 that face each other with the internal space 14 interposed therebetween. The electrode 2 is an electrode for forming a capacitance. Between the electrodes 2 facing each other, a capacitance according to the facing area and interval between the facing electrodes 2 is formed. For example, in the example shown in FIG. 1, when pressure is applied to the insulating substrate 1 from the outside, the flexible portion 13 is bent toward the internal space 14 in accordance with the pressure, and the interval between the opposing electrodes 2 is The capacitance is smaller than before the pressure is applied, and the capacitance between the electrodes 2 is increased. The pressure detection device can detect a change in external pressure as a change in capacitance by detecting such a change in capacitance. When the pressure is greatly reduced, the flexible portion 13 is deflected to the opposite side to the internal space 14 according to the pressure, and the interval between the opposing electrodes 2 is increased, so that the capacitance between the electrodes 2 is increased. It will be smaller.

  In plan view, the electrode 2 provided on the base portion 11 has a smaller area than the electrode 2 provided on the flexible portion 13 and is disposed so as not to protrude from the electrode 2 on the flexible portion 13 side. Is preferred. When the sizes of the electrodes 2 facing each other in plan view are different from each other, it is preferable to arrange the small electrodes 2 so as to overlap the entire large electrodes 2. With such a configuration, even when the opposing positions of the electrodes 2 facing each other are shifted when the insulating base 1 is manufactured, it is possible to reduce the reduction of the facing area between the electrodes 2. The rate of change in the distance between the electrodes 2 due to the change in pressure outside the flexible portion 13 is large at the center of the flexible portion 13 and small at the outer periphery of the flexible portion 13. Therefore, when the area of the electrode 2 provided on the base portion 11 is smaller than the area of the electrode 2 provided on the flexible portion 13, the center of the flexible portion 13 where the rate of change of the distance between the electrodes 2 is large. Since the ratio of the area where the electrodes 2 face each other can be improved, the rate of change in capacitance due to a change in external pressure increases, and the sensitivity of the pressure detection device can be increased.

  The wiring conductors 3 are formed on the surface and inside of the insulating base 1 and are electrically connected to the electrodes 2 facing each other, and the change in capacitance between the electrodes 2 is used as an electrical signal to generate an electronic signal. It functions as a wiring for transmitting to the component 5 and a wiring for transmitting an electrical signal calculated by the electronic component 5 to the external circuit board via the external terminal 4.

  The external terminal 4 is formed on the lower surface of the insulating base 1 and functions as a wiring for transmitting an electrical signal from the wiring conductor 3 to the external circuit board and a joint portion with the external circuit board.

The electrode 2, the wiring conductor 3, and the external terminal 4 are made of a metallized conductor using a metal powder such as tungsten, molybdenum, copper, or silver. For example, if the insulating substrate 1 is made of an aluminum oxide sintered body, a metallized paste obtained by adding and mixing an appropriate organic binder, solvent, plasticizer, dispersant, etc. to a metal powder such as tungsten is screen-printed. A predetermined pattern is formed on the surface and inside of the insulating substrate 1 by printing and applying a predetermined pattern on the ceramic green sheet for the insulating substrate 1 by the method, and baking this together with the ceramic green sheet laminate for the insulating substrate 1. Is done. The wiring conductor 3 extending vertically in the insulating substrate 1 is formed by forming a through hole in the ceramic green sheet and filling the through hole with a metallized paste.

On the surfaces of the exposed portions of the wiring conductor 3 and the external terminal 4, a metal plating layer having excellent corrosion resistance such as nickel and gold is applied. Corrosion of the wiring conductor 3 and the external terminal 4 can be reduced, and the connection between the electrode of the electronic component 5 and the wiring conductor 3 and the external circuit board and the external terminal 4 can be firmly joined. For example, a nickel plating layer having a thickness of about 1 to 10 μm and a gold plating layer having a thickness of about 0.1 to 3 μm are sequentially deposited on the surface of the exposed portion.

  The frame portion 12 is for providing a predetermined interval between the electrodes 2 facing each other. It has a frame shape having a through hole surrounding the internal space 14. If the thickness of the frame portion 12 is less than 0.01 mm, the distance between the electrodes 2 is relatively small, so that the flexible range of the flexible portion 13 is small. Get smaller. Also, if the thickness of the frame portion 12 exceeds 5 mm, the distance between the electrodes 2 is relatively large, so that the rate of change of the distance between the electrodes 2 is small and the rate of change of the capacitance is small. Sensitivity of the detection device is lowered. Therefore, it is preferable that the thickness of the part in which the frame part 12 forms the internal space 14 is 0.01 mm-5 mm.

  The flexible portion 13 bends to the inner space 14 side or the opposite side of the inner space 14 according to the external pressure, and functions as a pressure detecting diaphragm. In the example shown in FIG. 1, the flexible portion 13 overlaps the through hole of the frame portion 12 in the upper portion of the internal space 14. When the thickness of the flexible portion 13 is less than 0.01 mm, the mechanical strength is small, and there is a high possibility of breakage when it is produced using a ceramic green sheet. Further, when the thickness of the flexible portion 13 exceeds 1 mm, it becomes difficult to bend, and thus it becomes difficult to function as a diaphragm for the pressure detection device. Therefore, the thickness of the flexible portion 13 is preferably in the range of 0.01 to 1 mm. The pressure detection device using the pressure detection device substrate having the flexible portion 13 having such a thickness functions with high sensitivity under a pressure of, for example, 80 kPa (low pressure detection device) to 2000 kPa (high pressure detection device). To do.

  The internal space 14 is preferably a cylindrical shape having a circular shape in plan view. When the internal space 14 is circular in plan view, i.e., the through-hole of the frame portion 12 and the flexible portion 13 thereof are circular, when the external pressure is applied, the flexible portion 13 is evenly distributed. Easy to bend. Therefore, it is possible to reduce a large deformation of a part of the flexible portion 13 having a relatively small thickness, and to detect the external pressure with high sensitivity. In such a case, the electrode 2 preferably has a circular shape as in the shape of the internal space 14 in plan view. By setting it as such an electrode shape, the flexible part 13 can be bent equally.

  The electronic component 5 functions as an arithmetic unit that processes an electrical signal transmitted from the electrode 2 via the wiring conductor 3 and detects the magnitude and change of the external pressure. In addition, in the example shown in FIG. 1, although it is a semiconductor element as an arithmetic processing apparatus for performing the arithmetic processing mentioned above, other electronic components, such as passive elements, such as a chip capacitor and chip resistance, and an acceleration sensor, are mounted. It does not matter.

In the example shown in FIG. 1, the wire bonding type electronic component 5 is fixed to the bottom surface of the recess 15 with a bonding material (not shown) such as glass, resin, or brazing material, and then conductive bonding such as bonding wire is performed. The electronic component 5 and the wiring conductor 3 are connected via the material 6. Thereby, the electronic component 5 and the wiring conductor 3 are electrically connected, and the electronic component 5 is fixed to the insulating base 1.

  When the electronic component 5 is of a flip chip type, the electronic component 5 is bonded to the wiring conductor 3 in the recess 15 via the conductive bonding material 6. As the conductive bonding material 6 in this case, a solder bump, a gold bump, or a conductive resin (an anisotropic conductive resin or the like) is used.

  The electronic component 5 mounted on the bottom surface of the recess 15 is sealed in the recess 15 by being covered with a sealing resin such as an epoxy resin, for example. Alternatively, sealing may be performed by bonding a lid made of metal or ceramics to the insulating substrate 1 so as to cover the recess 15 so as to cover the electronic component 5 mounted in the recess 15.

  Since the base for the pressure detection device according to the present embodiment has the height of the electronic component mounting portion located below the height of the lower end of the internal space 14, the heat generated from the electronic component 5 mounted on the electronic component mounting portion. Can be transmitted more easily to the lower surface side of the insulating substrate 1 and to the external terminal 4 side than to the flexible portion 13 and less likely to be transmitted to the flexible portion 13. The external pressure can be detected with high accuracy by reducing the capacitance and suppressing the change in capacitance.

  In addition, the pressure detection device according to the present embodiment includes the pressure detection device base and the electronic component 5 mounted on the electronic component mounting portion of the pressure detection device base, and thus detects external pressure with high accuracy. It can be set as the pressure detection apparatus which can.

(Second Embodiment)
Next, a pressure detection apparatus according to a second embodiment of the present invention will be described with reference to FIGS.

  The pressure detection device in the present embodiment is different from the pressure detection device in the above-described embodiment in that the width W1 of the internal space 14 is smaller than the width W2 of the recess 15 in plan view. In addition, a passage 16 connected to the internal space 14 is provided on the upper surface of the insulating base 1, and one of the electrodes 2 is provided inside the base portion 11.

  Here, the width W1 of the internal space 14 is the maximum width (diameter) in a direction orthogonal to the direction in which the internal space 14 and the concave portion 15 are arranged, and the width W2 of the concave portion 15 is the internal space 14. And the width in the direction orthogonal to the direction in which the recess 15 is arranged.

  In the pressure detection device base body of the present embodiment, when the width W1 of the internal space 14 is smaller than the width W2 of the recess 15 in plan view, the width of the frame 12 around the internal space 14 is large. Even if an external stress is applied to the pressure detection device, the external stress is dispersed by the frame portion 12, and the flexible portion 13 is not easily deformed by the external stress. It can be detected with high accuracy.

  Further, the passage 16 is used as a passage for discharging the gas generated when the insulating substrate 1 is fired from the internal space 14 to the outside. Since the pressure detection device base has the passage 16, it is possible to reduce deformation of the flexible portion 13 when the pressure detection device base is manufactured. The passage 16 is sealed by the sealing material 7 after the insulating substrate 1 is baked as in the example shown in FIGS. 3 and 4. When an Ag brazing material is used as the sealing material 7, a bonding layer made of metal is provided in the opening of the passage 16, and sealing is performed by bonding the Ag brazing material to the bonding layer.

When the electrode 2 provided in the base part 11 is embedded in the base part 11 or the electrode 2 provided in the flexible part 13 is embedded in the flexible part 13, it is large from the outside. When the pressure is applied, it can be reduced that the flexible portion 13 is greatly bent and the electrodes 2 are short-circuited. Further, when the electrode 2 provided on the base portion 11 is smaller than the electrode 2 provided on the flexible portion 13, when the pressure detecting device base is immersed in the plating solution, the passage 16 enters the internal space 14. It can be reduced that the plating solution enters and plating is applied to the surface of the electrode 2 to increase the area of the electrode 2.

  The electrode 2 embedded in the base portion 11 can be produced by laminating another ceramic green sheet on the ceramic green sheet on which the metallized paste for the electrode 2 is printed. Alternatively, a ceramic paste substantially the same quality as the ceramic green sheet and a metallized paste for the electrode 2 are printed on the ceramic green sheet on which the metalized paste for the electrode 2 is printed. The ceramic paste is manufactured by adding an organic binder and organic solvent to the main component ceramic powder, and adding a dispersing agent if necessary, and mixing and kneading with a kneading means such as a ball mill, a three-roll mill or a planetary mixer. The In addition, when the insulating layer is formed of a ceramic green sheet, the variation in the thickness of the insulating layer on the electrode 2 can be reduced as compared with the case of forming the ceramic paste by printing. A substrate for a pressure detection device with small variations can be obtained. The distance from the electrode 2 to the upper surface of the base portion 11 that is in contact with the internal space 14 is preferably 15 μm or more.

  If such a passage 16 is provided in a region opposite to the region where the recess 15 is provided on the upper surface of the insulating base 1 as in the example shown in FIG. 3, the internal space 14 and the recess 15 Since the width of the insulating base 1 between the two is increased, it is preferable in terms of airtightness of the internal space 14 of the base for the pressure detection device and miniaturization of the pressure detection device.

  In addition, as shown in FIG. 4, a second frame portion 17 arranged so as to surround the flexible portion 13 may be formed above the flexible portion 13. The 2nd frame part 17 is for suppressing the possibility that the flexible part 13 will contact the exterior directly, and the flexible part 13 will be damaged. Such a second frame portion 17 is manufactured in the same manner as the base portion 11, the frame portion 12, and the flexible portion 13.

(Third embodiment)
Next, a pressure detection apparatus according to a third embodiment of the present invention will be described with reference to FIG.

  The pressure detection device in the present embodiment is different from the detection device in the above-described embodiment in that the metal layer 8 is provided between the lower surface of the insulating base 1 and the bottom surface of the recess 15 in a longitudinal sectional view. is there.

  If the metal layer 8 as described above is provided, the heat generated in the electronic component 5 is likely to be transferred from the bottom surface of the recess 15, that is, the electronic component mounting portion, to the metal layer 8 having better thermal conductivity than the insulating base 1. Therefore, it is easy to be transmitted to the lower surface of the insulating substrate 1, and the heat of the electronic component 5 can be easily released from the lower surface of the insulating substrate 1 to the outside. That is, heat transfer to the flexible portion 13 is suppressed, and deformation of the flexible portion 13 due to thermal stress is further reduced to suppress a change in capacitance, whereby external pressure can be detected more accurately. it can. Such a metal layer 8 can be manufactured by the same material and method as the above-described electrode 2, wiring conductor 3, and external terminal 4.

  In the example shown in FIG. 5, the metal layer 8 extends below the internal space 14. The extending portion of the metal layer 8 functions as a shield layer, and noise from the lower outside of the lower surface of the insulating base 1 to the electrode 2 can be suppressed, and the external pressure can be detected with high accuracy. Note that a shield layer may be provided independently of the metal layer 8 below the internal space 14 without extending the metal layer 8.

  Further, as in the example shown in FIG. 5, the wiring conductor 3 disposed between the bottom surface of the recess 15 and the external terminal 4 on the lower surface of the insulating base 1 is closer to the lower surface of the insulating base 1 than the metal layer 8. Arrangement is preferable because unnecessary capacitance can be prevented from being generated between the electrode 2 and the wiring conductor 3.

  A metal layer may be provided on the upper surface of the flexible portion 13 so that noise from the upper surface direction of the insulating base 1 toward the electrode 2 can be suppressed.

  In addition, a metal conductor having higher thermal conductivity than the insulating base 1 is provided between the bottom surface of the recess 15 and the metal layer 8 or between the metal layer 8 and the lower surface of the insulating base 1 in the thickness direction of the insulating base 1. A heat-dissipating layer having better thermal conductivity than the insulating base 1 is provided on the lower surface of the insulating base 1 that overlaps with the bottom surface of the recess 15 in a plan view, and the heat generated from the electronic component 5 It may be easy to be transmitted to the lower surface side.

  In addition, this invention is not limited to the example of said embodiment, A various change is possible. For example, in the example shown in FIG. 1, the electronic component 5 is mounted on the bottom surface of the recess 15 provided in the insulating base 1, but as in the examples shown in FIGS. 6 and 7, the insulating base 1 It may be mounted on the step 18 having the electronic component mounting portion on the upper surface.

  Further, as in the example shown in FIGS. 6 and 7, the external terminals 4 may be arranged more on the electronic component 5 side than on the internal space 14 side in the bottom view.

  Moreover, the external terminal 4 is provided with two or more external terminals 4 from the lower surface of the insulating base | substrate 1 to an outer surface like the example shown by FIGS. That is, a notch is formed on the side surface of the insulating base 1, and the external terminal 4 functioning as a terminal electrode is provided as a so-called castellation conductor on the inner surface of the notch.

1. Insulating substrate
11 ... Base part
12 ... Frame
13 ... Flexible part
14 ... Interior space
15 ... Recess
16 .... Passage
17 ··· Second frame
18 .... Step 2 ... Electrode 3 ... Wiring conductor 4 ... External terminal 5 ... Electronic component 6 ... Conductive bonding material 7 ... Sealing material 8 ... Metal layer

Claims (3)

An insulating base having an internal space, an upper surface provided in line with the internal space in a plan view and including an electronic component mounting portion, and a flexible portion provided adjacent to the internal space;
A plurality of electrodes provided on the inner surface of the internal space or inside the insulating base so as to sandwich the internal space;
An external terminal provided on the lower surface of the insulating base,
A base for a pressure detection device, wherein the height of the electronic component mounting portion is located below the height of the lower end of the internal space.   The pressure detecting device base according to claim 1, further comprising a metal layer between a lower surface of the insulating base and the electronic component mounting portion. A base for a pressure detection device according to claim 1;
An electronic component mounted on the electronic component mounting portion of the base for the pressure detection device.

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