JP2011095019A - Substrate for pressure detection device and pressure detection device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a substrate for pressure detection device that can accurately detect pressure in the outside and is superior in reliability and to provide a pressure detection device. <P>SOLUTION: The substrate for pressure detection device includes: an insulation substrate 1 that has an inner space 1a wherein upper and lower surfaces opposite to each other in parallel and a plurality of electrode conductor layers 2 on its surface; and an upper electrode 3 and a lower electrode 4 that are formed on the upper and lower surface of the inner space 1a respectively while they are connected with at least one of the electrode conductor layers 2 and are opposite to each other, and at least either of the upper and lower surfaces is a flexible area 1e. Furthermore, an electrode 6 for detection is provided on the surface of an insulation layer 5 corresponding to the central part of the flexible area 1e and is electrically independent of the upper and lower electrodes 3 and 4, to detect a contact with the upper electrode 3 or the lower electrode 4 that is covered with the insulation layer 5. The contact of a diaphragm with the counter surface can be detected by shortcircuiting between the upper electrode 3 or the lower electrode 4 and the electrode 6 for detection. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

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

  Conventionally, there is a capacitance type pressure detection device 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 interval is provided between an insulating substrate made of ceramics having a first electrode for forming a capacitance formed on the surface, and the insulating substrate. A diaphragm made of ceramics provided with a space and bonded in a flexible manner to the surface of the insulating substrate and having a second electrode for forming a capacitance so as to face the first electrode It has been known. In this pressure detecting device base, an insulating substrate, a diaphragm, and a spacer therebetween are integrally formed, and thereby an internal space sealed by the insulating base is formed. According to this, 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 (see, for example, Patent Document 1).

  In such a pressure detection device substrate, conductive foreign matter may enter the internal space, and in this case, the first electrode and the second electrode may be short-circuited via the conductive foreign matter. there were. For example, when an insulating substrate and a diaphragm are joined, there is a possibility that the assembly jig made of carbon and the diaphragm come into contact with each other and a part of the assembly jig is lost, and carbon waste enters the internal space. (For example, see Patent Document 2). As a method for preventing such a short circuit between the first electrode and the second electrode, conventionally, a measure has been taken in which the entire surface of the first electrode is covered with an insulating layer ( For example, see Patent Document 3.)

  Further, some pressure detection device bases have a gap extending from the internal space to the outer surface of the pressure detection device base (see, for example, Patent Document 4). In such a pressure detection device substrate, when the plating layer is deposited on the conductor layer provided on the surface, the plating solution penetrates into the internal space from the gap and the plating spreads around the electrode. Therefore, there has been a concern that the area of the opposing electrodes may change. Even in such a case, it is effective to coat the surface of the electrode with an insulating layer.

JP 2007-171053 JP 2006-208129 A Japanese Patent Laid-Open No. 4-104028 JP 2008-180695 A

  However, in the pressure detection device in which the surface of the first electrode is covered with the insulating layer as described above, even if the external pressure changes, the capacitance between the first electrode and the second electrode Changes may be difficult or may not occur. This is because when the diaphragm bends due to a change in external pressure and comes into contact with the insulating layer, even if pressure is further applied to the diaphragm from the outside, the diaphragm becomes difficult to bend or does not bend. This is because the distance between the two electrodes becomes difficult to change or does not change. In such a case, when the detected electrostatic capacity is processed by an electronic component or the like, the first electrode and the second electrode are actually connected even though the external pressure actually changes. Since no change has occurred in the capacitance between the two, the pressure detection device cannot detect a change in external pressure. In such a case, the diaphragm is difficult to bend or no longer bends, so it cannot be determined whether a change in the external pressure cannot be detected or whether the external pressure has actually changed. There was a problem.

  Such a contact between the diaphragm and the insulating layer is due to the fact that the distance between the first electrode and the second electrode has become narrow due to the recent demand for higher sensitivity of the pressure detection device, and for the pressure detection device. This occurs due to variations in the distance between the first electrode and the second electrode for each substrate, variations in the way the diaphragm is bent, and the like.

  The present invention has been devised in view of the above-described problems of the prior art, and an object of the present invention is to provide a highly reliable base for pressure detection device and a pressure detection device that can accurately detect external pressure. It is to provide.

  The substrate for a pressure detection device of the present invention has an internal space having an upper surface and a lower surface facing in parallel to each other, an insulating substrate made of ceramics having a plurality of electrode conductor layers on the surface, the upper surface of the internal space, and An upper electrode and a lower electrode facing each other and electrically connected to at least one of the electrode conductor layers on the lower surface, and an insulating layer covering the upper electrode or the lower electrode A surface of the insulating layer corresponding to a central portion of the flexible region, wherein at least one of the upper surface and the lower surface is a flexible region that is a flexible region that bends when pressure is applied from the outside. Further, a detection electrode for detecting contact with the upper electrode or the lower electrode that is electrically independent from the upper electrode and the lower electrode and is not covered with the insulating layer And it is characterized in that it comprises.

  The pressure detection device of the present invention is characterized in that an electronic component is electrically connected to the electrode conductor layer of the pressure detection device substrate having the above-described configuration.

  According to the pressure sensing device substrate of the present invention, the upper electrode that is electrically independent from the upper electrode and the lower electrode and is not covered with the insulating layer on the surface of the insulating layer corresponding to the central portion of the flexible region. Alternatively, since a detection electrode for detecting contact with the lower electrode is provided, the flexible region of the diaphragm is greatly bent due to a change in external pressure, and the diaphragm comes into contact with the surface facing the diaphragm. Sometimes, the upper electrode or the lower electrode not covered with the insulating layer is in contact with the detection electrode formed on the surface of the insulating layer corresponding to the central portion of the flexible region, so that it is not covered with the insulating layer. The upper electrode or the lower electrode and the detection electrode are short-circuited. Then, by short-circuiting, it is possible to detect that the diaphragm is in contact with the surface facing the diaphragm, so that the diaphragm is not deformed even when pressure is further applied, and the capacitance is difficult to change or changes. You can detect not.

  If such a pressure detection device substrate is used, for example, when an inspection is performed before shipping a product, an upper electrode or a lower electrode and a detection electrode that are not covered with an insulating layer within a desired pressure range. By inspecting whether or not they are short-circuited, the pressure-detecting device substrate that is short-circuited can be removed as a defective product. Therefore, it is possible to select only a pressure detection device substrate that can detect a pressure well within a desired pressure range at the time of inspection before shipping the product. Further, in the case of the pressure detection device using the substrate for pressure detection device of the present invention, even if the diaphragm and the surface facing the diaphragm may come into contact during use, the pressure detection device It can be detected that the pressure cannot be properly measured.

  According to the pressure detection device of the present invention, since the electronic component is electrically connected to the electrode conductor layer of the pressure detection device base having the above-described configuration, the pressure change from the outside can be detected by the pressure detection device base. By detecting with high accuracy and processing the output signal according to the change in capacitance due to the change in pressure by the electronic component, the change in capacitance can be detected with high accuracy as the change in external pressure value.

(A) is a top view which shows an example of embodiment of the base | substrate for pressure detection apparatuses of this invention, (b) is an internal top view which shows an example of embodiment of the base | substrate for pressure detection apparatuses of (a). is there. It is a bottom view. It is sectional drawing which shows an example of the cross section in the AA line of Fig.1 (a). It is sectional drawing which shows the other example of embodiment of the base | substrate for pressure detection apparatuses of this invention. It is sectional drawing which shows the other example of embodiment of the base | substrate for pressure detection apparatuses of this invention. It is sectional drawing which shows the other example of embodiment of the base | substrate for pressure detection apparatuses of this invention. It is sectional drawing which shows an example of embodiment of the pressure detection apparatus of this invention.

  The substrate for a pressure detection device and the pressure detection device of the present invention will be described with reference to the accompanying drawings. 1 to 5, 1 is an insulating substrate, 1a is an internal space, 1b is an insulating substrate, 1c is a spacer, 1d is a diaphragm, 1e is a flexible region, 1f is a wiring conductor, 1g is a frame, 1h is a recess, 1i is a notch-shaped recess, 2 is an electrode conductor layer, 3 is an upper electrode, 4 is a lower electrode, 5 is an insulating layer, 6 is a detection electrode, 6a is a detection electrode wiring, 7 is an electronic component, 8 is a conductive bonding material, and 9 is a sealing resin.

  The base for a pressure detection device of the present invention has an internal space 1a having an upper surface and a lower surface that face each other in parallel, and has a plurality of electrode conductor layers 2 on the surface, as in the examples shown in FIGS. The upper electrode 3 and the lower electrode 4 facing each other, and the upper electrode 3 formed on the upper surface and the lower surface of the insulating space 1a and electrically connected to at least one of the electrode conductor layers 2, respectively. Or an insulating layer 5 that covers the lower electrode 4, and at least one of the upper surface and the lower surface is a flexible region 1 e that is a flexible region 1 e that is bent when pressure is applied from the outside, and the flexible region The surface of the insulating layer 5 corresponding to the central portion of 1e is brought into contact with the upper electrode 3 or the lower electrode 4 that is electrically independent from the upper electrode 3 and the lower electrode 4 and is not covered with the insulating layer 5. Equipped with detection electrode 6 for detection There.

  In the example shown in FIGS. 1, 2, and 5, the insulating layer 5 is formed on the lower surface of the internal space 1a (the upper surface of the lower electrode 4 on the upper surface of the insulating substrate 1b), and the detection electrode 6 is the insulating layer. 5 is formed on the surface. In the example shown in FIGS. 3 and 4, the insulating layer 5 is formed on the upper surface of the internal space 1a (the lower surface of the upper electrode 3 on the lower surface of the diaphragm 1d), and the detection electrode 6 is formed on the surface of the insulating layer 5. Has been. 1 (a) shows the internal space 1a, the wiring conductor 1f, the upper electrode 3, the lower electrode 4, the insulating layer 5 and the detection electrode 6 in a perspective view, and FIG. 1 (b) shows the lower electrode. 4 is seen through.

  According to the pressure detecting device substrate of the present invention, when the diaphragm 1d bends and contacts the insulating layer 5 due to a change in external pressure, the upper electrode 3 or the lower electrode 4, the upper electrode 3, The detection electrode 6 formed at a position corresponding to the center of the most flexible region of the flexible region where the distance from the lower electrode 4 is the smallest will come into contact, and the diaphragm 1d further changes. It is difficult to detect that the capacitance between the upper electrode 3 and the lower electrode 4 is difficult to change. Therefore, by inspecting the presence or absence of contact with the upper electrode 3 or the lower electrode 4 with the detection electrode 6, the relationship between the capacitance and the pressure is a desired relationship within a desired pressure range. A substrate for a pressure detection device that can be detected well can be obtained.

  According to such a pressure detecting device substrate of the present invention, when the flexible region 1e of the diaphragm 1d is largely bent due to a change in the external pressure and the diaphragm 1d contacts the surface facing the diaphragm 1d, the insulating layer 5 Since the uncovered upper electrode 3 or lower electrode 4 and the detection electrode 6 formed on the surface of the insulating layer 5 corresponding to the central portion of the flexible region 1e are in contact with each other, they are not covered with the insulating layer 5. The upper electrode 3 or the lower electrode 4 and the detection electrode 6 are short-circuited. By short-circuiting, it can be detected that the diaphragm 1d is in contact with the surface facing the diaphragm 1d, so that the diaphragm 1d is not deformed even when pressure is further applied, and the capacitance is difficult to change. Or, it can be detected that there is no change.

  If such a pressure detection device substrate is used, for example, when the product is inspected before shipment, the upper electrode 3 or the lower electrode 4 not covered with the insulating layer 5 within a desired pressure range can be obtained. By inspecting whether or not the detection electrode 6 is short-circuited, the pressure-detecting device substrate that is short-circuited can be removed as a defective product. Therefore, it is possible to select a pressure detection device base body that can detect pressure well within a desired pressure range in the inspection before shipping the product. Further, in the case of the pressure detection device using the base for pressure detection device of the present invention, even if the diaphragm 1d and the surface facing the diaphragm 1d may be in contact with each other at the time of use, the contact is detected to detect the pressure. It can be detected that the device is in a state where the pressure cannot be measured properly.

  The insulating substrate 1 is 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 an electrically insulating sintered body such as glass ceramics. For example, as shown in FIG. 2, the insulating substrate 1b, the frame-like spacer 1c, and the diaphragm 1d whose central portion is the flexible region 1e are formed, and these are laminated in order to form the internal space. 1a is formed.

  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. These ceramic green sheets are appropriately punched and cut to obtain ceramic green sheets for the insulating substrate 1 (for the insulating substrate 1b, for the spacer 1c, and for the diaphragm 1d). At this time, the ceramic green sheet for the spacer 1c is formed with a through hole serving as the internal space 1a 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 1a is formed. Then, by firing this ceramic green sheet laminate at a temperature of about 1600 ° C., the insulating substrate 1 having the internal space 1a is manufactured.

  As shown in the example shown in FIGS. 5 and 6, the insulating base 1 is formed with a recess 1 h for housing the electronic component 7 on the surface of the insulating base 1 that faces the surface on which the flexible region 1 e is formed. It doesn't matter. In this case, the insulating substrate 1 functions as a container for housing the electronic component 7 and protecting the electronic component 7.

  Moreover, the insulating base | substrate 1 may be provided with the frame 1g on the outer peripheral part of the diaphragm 1d like the example shown in FIGS. The frame 1g has a frame-like shape similar to the spacer 1c, which is laminated in a region outside the flexible region 1e on the upper surface of the diaphragm 1d. According to this, when the ceramic green sheet laminate for the insulating substrate 1 is formed, the ceramic green sheet for the diaphragm 1d is formed in the vertical direction by the ceramic green sheet for the spacer 1c and the ceramic green sheet for the frame 1g. Since it is formed by being sandwiched, warping during firing of the diaphragm 1d can be suppressed. Since the frame 1g protrudes from the outer surface of the flexible region 1e, the ceramic green sheet laminate for the insulating substrate 1 before firing, the substrate for pressure detection device after firing, and the flexible region 1e of the pressure detection device. It is possible to reduce the possibility that the thin flexible region 1e will be damaged.

  The electrode conductor layer 2 on the surface of the insulating base 1 functions as a terminal electrode for transmitting a change in capacitance between the upper electrode 3 and the lower electrode 4 to the external circuit board as an electrical signal. In addition, the electrode conductor layer 2 and each of the upper electrode 3 and the lower electrode 4 are electrically connected by a wiring conductor 1 f formed inside the insulating substrate 1. Further, as in the example illustrated in FIG. 6, when the electronic component 7 is mounted on the pressure detection device, the electrode conductor layer 2 that functions as a connection electrode to which the terminal of the electronic component 7 is connected is provided. Such an electrode conductor layer 2 is provided on the surface of the insulating substrate 1 other than the flexible region 1e. 2 to 4, the electrode conductor layer 2 is provided on the lower surface of the insulating base 1, but the electrode conductor layer 2 may be provided on the side surface of the insulating base 1. Alternatively, as in the example shown in FIGS. 5 and 6, a notch-shaped recess 1 i is formed on the side surface of the insulating base 1, and the electrode conductor layer 2 functioning as a terminal electrode is provided on the inner surface of the recess 1 i. A so-called castellation conductor may be used.

  A lower electrode 4 is deposited on the lower surface of the internal space 1a of the insulating base 1 (the upper surface of the insulating substrate 1b in the example shown in FIG. 2), and the upper surface of the internal space 1a of the insulating base 1 (in the example shown in FIG. 2). The upper electrode 3 is attached to the lower surface of the diaphragm 1d so as to face the lower electrode 4. The lower electrode 4 and the upper electrode 3 are electrodes for forming a capacitance, depending on the area in which the lower electrode 4 and the upper electrode 3 face each other and the distance between the lower electrode 4 and the upper electrode 3. Capacitance is formed. In the example shown in FIGS. 2 and 3, when a pressure is applied to the insulating substrate 1 from the outside, the flexible region 1e of the diaphragm 1d bends toward the insulating substrate 1b in accordance with the pressure, and the lower electrode 4 and the upper electrode 3 changes (becomes smaller), and the capacitance between the lower electrode 4 and the upper electrode 3 changes (becomes larger), so that the external pressure can be detected by detecting this change in capacitance. It functions as a pressure detection device that detects changes in capacitance as changes in capacitance. When the pressure greatly decreases, the flexible region 1e of the diaphragm 1d bends in the opposite direction to the insulating substrate 1b according to the pressure, and the interval between the lower electrode 4 and the upper electrode 3 changes (becomes larger). In this case, the capacitance between the lower electrode 4 and the upper electrode 3 changes (becomes smaller) from the equilibrium state.

  In the example shown in FIG. 4, when pressure is applied to the insulating substrate 1 from the outside, the flexible regions 1e of the diaphragm 1d provided above and below the internal space 1a according to the pressure are respectively located on the internal space 1a side. The distance between the lower electrode 4 and the upper electrode 3 is changed by bending (becomes smaller), and the capacitance between them changes (becomes larger). Also in this example, when the pressure is greatly reduced, the flexible regions 1e of the diaphragm 1d provided above and below the inner space 1a according to the pressure bend to the opposite side to the inner space 1a, respectively, so that the lower electrode 4 and the upper electrode 4 The distance from the electrode 3 may change (become larger), and at that time, the electrostatic capacitance between the lower electrode 4 and the upper electrode 3 will change (become smaller) from the equilibrium state.

  Then, by transmitting this change in capacitance to the external circuit board as an electrical signal through the electrode conductor layer 2, and performing arithmetic processing with an electronic component such as an arithmetic processing device mounted on the external circuit board, The magnitude and change of external pressure can be known. Here, as in the example shown in FIG. 6, when the recess 1 h is formed in the insulating base 1 and the electronic component 7 such as an arithmetic processing unit is mounted in the recess 1 h, the change in capacitance is caused by an external circuit. It is transmitted not to the substrate but to the electronic component 7 in the recess 1h.

  The electrode conductor layer 2, the upper electrode 3, the lower electrode 4 and the wiring conductor 1f are made of a metallized conductor using a metal powder such as tungsten, molybdenum, copper or silver. For example, the insulating substrate 1 is sintered with an aluminum oxide material. In the case of a 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 applied to a ceramic green sheet for the insulating substrate 1 by screen printing. A predetermined pattern is printed and applied, and this is fired together with the ceramic green sheet laminate for the insulating substrate 1 to form a predetermined pattern inside and on the surface of the insulating substrate 1. The wiring conductor 1f extending in the vertical direction 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.

  In the example shown in FIGS. 2 and 3, the spacer 1c is provided between the insulating substrate 1b having the lower electrode 4 on the upper surface and the diaphragm 1d having the upper electrode 3 on the lower surface. In the example shown in FIG. Each of them functions as providing a predetermined interval between 1d, and is formed in a frame shape having a through hole that forms the internal space 1a. If the thickness of the spacer 1c is less than 0.01 mm, the distance between the lower electrode 4 and the upper electrode 3 is small and the flexible range of the flexible region 1e is small. Therefore, the pressure is detected over a wide pressure range. Tend to be difficult to do. On the other hand, if it exceeds 5 mm, the distance between the lower electrode 4 and the upper electrode 3 becomes large with respect to the amount of deflection of the flexible region 1e, so that the rate of change of the interelectrode distance becomes small and the rate of change of capacitance. Tends to be small and the sensitivity is low. Therefore, the thickness of the spacer 1c is preferably in the range of 0.01 mm to 5 mm.

  The diaphragm 1d bends to the insulating substrate 1b side depending on the external pressure and, in some cases, to the opposite side, and functions as a pressure detecting diaphragm. In the example shown in FIG. 2, the portion of the diaphragm 1d that becomes the upper surface of the internal space 1a, that is, the region that overlaps the through hole of the spacer 1c becomes the flexible region 1e, and the flexible region 1e is bent by pressure applied from the outside. Will be lost. If the thickness of the diaphragm 1d is less than 0.01 mm, its mechanical strength tends to be low, and it tends to be difficult to produce using the above-described ceramic green sheet. On the other hand, when it exceeds 1 mm, it becomes difficult to bend at a small pressure, and it tends to be unsuitable as a diaphragm for a pressure detection device. Therefore, the thickness of the diaphragm 1d is preferably in the range of 0.01 to 1 mm. The pressure detection device using the pressure detection device base having the diaphragm 1d having such a thickness can be used under a pressure of 80 kPa (pressure detection device for low pressure) to 2000 kPa (pressure detection device for high pressure). is there.

  The internal space 1a is preferably a circular cylindrical shape in plan view. When the internal space 1a is circular in plan view, that is, the through-hole of the spacer 1c and the flexible region 1e of the diaphragm 1d are circular, when the external pressure is applied, the flexible region 1e of the diaphragm 1d is evenly distributed. Since a part of the thin diaphragm 1d is not greatly deformed, the external pressure can be detected with high sensitivity without being broken.

  Moreover, it is preferable that the upper electrode 3 and the lower electrode 4 formed in the diaphragm 1d have a circular shape in plan view, like the shape of the internal space 1a. By setting it as such an electrode shape, the flexible area | region 1e of the diaphragm 1d can be bent equally.

  Moreover, it is preferable that at least one of the upper electrode 3 and the lower electrode 4 is smaller than the upper surface or the lower surface where the internal space 1a is provided. The rate of change of the interelectrode distance between the upper electrode 3 and the lower electrode 4 due to fluctuations in external pressure is large at the center side in the planar direction of the internal space 1a and small at the outer peripheral side of the internal space 1a. Therefore, if at least one of the upper electrode 3 and the lower electrode 4 is smaller than the upper surface or the lower surface where the internal space 1a is provided, only at the central portion of the internal space 1a where the change rate of the interelectrode distance is large. Since the upper electrode 3 and the lower electrode 4 can be made to face each other, the rate of change of the capacitance formed by the upper electrode 3 and the lower electrode 4 due to the application of external pressure increases, and the pressure detection device Can increase the sensitivity.

  Assuming that one of the upper electrode 3 and the lower electrode 4 is larger than the other, the upper electrode 3 and the lower electrode 4 are positioned even when there is a positional shift between the upper electrode 3 and the lower electrode 4 when the insulating substrate 1 is manufactured. This is preferable because the area facing the side electrode 4 does not change. Furthermore, in this case, when the electrode formed on the diaphragm 1d, the upper electrode 3 in the example shown in FIG. 1, is made larger than the upper surface of the internal space 1a as in the examples shown in FIGS. 1 and 2, external pressure is applied. In this case, the diaphragm 1d can be flexed well, which is preferable. For example, if the upper electrode 3 smaller than the flexible region 1e of the diaphragm 1d is formed, there is a difference in deflection between the region where the upper electrode 3 is formed and the region where the upper electrode 3 is not formed in the flexible region 1e. This is because, if this difference is large, it may break at the boundary between these regions.

  The insulating layer 5 is made of an electrically insulating material such as an aluminum oxide sintered body, a mullite sintered body, an aluminum nitride sintered body, or a silicon carbide sintered body. As in the example shown in FIG. 2, when the area of the lower electrode 4 is smaller than the area of the lower surface of the internal space 1 a (the upper surface of the insulating substrate 1 b), the insulating layer 5 covers the lower electrode 4. Formed. When the insulating layer 5 is formed so as to cover the lower electrode 4 as in the example shown in FIG. 2, the lower side printed on the ceramic green sheet for the insulating base 1 that becomes the lower surface of the internal space 1 a By printing and applying a ceramic paste for the insulating layer 5 on the metallized paste for the electrode 4 by a printing means such as a screen printing method, and simultaneously firing the ceramic paste with the ceramic green sheet laminate for the insulating substrate 1, An insulating layer 5 covering the lower electrode 4 is formed. The ceramic paste for the insulating layer 5 is mixed and kneaded by kneading means such as a ball mill, a three-roll mill or a planetary mixer after adding an organic binder and an organic solvent and, if necessary, a dispersant to the ceramic powder of the main component. Produced.

  Further, as shown in FIG. 5, at least one of the upper electrode 3 and the lower electrode 4 may be embedded in the insulating base 1. In this case, a part of the insulating substrate 1 can be used as the insulating layer 5. Such an insulating layer 5 can be formed by laminating a ceramic green sheet for the insulating substrate 1 to be the insulating layer 5 on a ceramic green sheet on which a metallized paste for the lower electrode 4 is printed. it can. In this case, since the insulating layer 5 is formed using a ceramic green sheet, the thickness variation of the insulating layer 5 can be reduced as compared with the case where the insulating layer 5 is formed by printing a ceramic paste. An excellent substrate for a pressure detection device can be obtained.

  The insulating layer 5 is preferably formed with a thickness of 15 μm or more from the surface of the electrode and extending from the surface of the electrode to the outside of the outer periphery of the electrode by 15 μm or more. Thus, by setting the thickness and width of the insulating layer 5 to 15 μm or more, defects such as cavities occur in the insulating layer 5, and the plating layer deposited on unnecessary areas and the area of the internal space 1 a are larger. It is possible to suppress electrical connection with a small electrode.

  And in the base | substrate for pressure detection apparatuses of this invention, the electrode for a detection which is electrically independent of the upper side electrode 3 and the lower side electrode 4 on the surface of the insulating layer 5 corresponding to the center part of the flexible area | region 1e. 6 is provided. The detection electrode 6 is electrically connected to one of the electrode conductor layers 2 via the detection electrode wiring 6a and the wiring conductor 1f.

  Similarly to the electrode conductor layer 2, the detection electrode 6 and the detection electrode wiring 6a are made of a metallized conductor using a metal powder such as tungsten, molybdenum, copper or silver. For example, the insulating layer 5 is made of an aluminum oxide material. In the case of a sintered body, a metallized paste obtained by adding and mixing a suitable organic binder, solvent, plasticizer, dispersant, etc. to a metal powder such as tungsten is a ceramic paste for the insulating layer 5 by screen printing. The surface of the insulating layer 5 is formed on the surface of the insulating layer 5 corresponding to the central portion of the flexible region 1e by printing and coating on the surface of the substrate and firing it together with the ceramic green sheet laminate for the insulating substrate 1.

  When the metallized paste for the detection electrode 6 is printed on the ceramic green sheet to be the insulating layer 5, the metallized paste for the detection electrode 6 is printed better than when printing on the surface of the ceramic paste. Therefore, the detection electrode 6 can be easily formed with high accuracy.

  In addition, the insulating layer 5 and the detection electrode 6 are as in the example shown in FIGS. 2 and 5 if the upper surface of the internal space 1a is a flexible region 1e that bends when pressure is applied from the outside. The inner space 1a is preferably formed on the lower surface side (the surface side of the lower electrode 4 of the insulating substrate 1b). Thereby, since the insulating layer 5 and the detection electrode 6 are not formed on the upper surface side, the insulating layer 5 and the detection electrode 6 are formed on the upper surface side of the internal space 1a (the surface side of the upper electrode 3 of the diaphragm 1d). Compared to the case where the flexible region 1e is formed, the flexible region 1e can be formed in a thin and flat state, so that the sensitivity of the pressure detecting substrate due to fluctuations in external pressure can be improved.

  Further, as shown in the examples of FIGS. 5 and 6, the detection electrode 6 may be connected to the electrode conductor layer 2 that functions as a connection electrode to which the terminal of the electronic component 7 is connected. In this case, the electronic component 7 can detect that the upper electrode 3 and the detection electrode 6 are in contact with each other during use of the pressure detection device.

  Further, the detection electrode 6 is a circle in which the insulating substrate 1 is 5 mm to 15 mm long, 5 mm to 15 mm wide, 2 mm to 5 mm thick, and the flexible region 1 e of the diaphragm 1 d has a radius of about 2 mm to 5 mm in plan view. In the case of a shape, it is formed in a circular shape with a radius of about 0.05 mm to 1 mm so that the center is located in a region corresponding to a range within a radius of 0.05 mm from the center of the flexible region 1e of the diaphragm 1d. It is preferable. If the detection electrode 6 is formed in a shape other than a circular shape such as a square shape, the area of the flexible region 1e including the region corresponding to the radius within 0.05 mm from the center portion described above is included. It is preferable to form it so as to be about 0.01% to 5%.

  For example, if the insulating substrate 1 is 5 mm long, 5 mm wide, and 2 mm thick, and the flexible region 1e of the diaphragm 1d has a circular shape with a radius of about 2 mm, the center of the flexible region 1e of the diaphragm 1d A circular shape having a radius of about 0.05 mm is formed in a region corresponding to a range within a radius of 0.1 mm. Further, if the insulating substrate 1 is 15 mm long, 15 mm wide, and 5 mm thick and the flexible region 1e of the diaphragm 1d has a circular shape with a radius of about 5 mm, the center of the flexible region 1e of the diaphragm 1d is removed. A circular shape with a radius of about 1 mm is formed in a region corresponding to a range of a radius of 1 mm.

  If the detection electrode 6 is formed in the above range and area, the insulating layer 5 and the detection electrode 6 are disposed on the lower surface side of the internal space 1a (on the insulating substrate 1b) as in the examples shown in FIGS. In the case of being formed on the surface side of the lower electrode 4, contact between the detection electrode 6 and the upper electrode 3, and as shown in FIGS. 3 and 4, the insulating layer 5 and the detection electrode 5 When the electrode 6 is formed on the upper surface side of the internal space 1a (the lower surface of the upper electrode 3 on the lower surface of the diaphragm 1d), the contact between the detection electrode 6 and the lower electrode 4 is detected respectively. It is valid.

  It should be noted that the exposed surface of the electrode conductor layer 2 prevents the electrode conductor layer 2 from being oxidatively corroded and is electrically conductive such as solder for joining the electrode conductor layer 2 and the wiring conductor of the external circuit board. In order to improve the bonding with the conductive bonding material 8, 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 by an electrolytic plating method.

  In the above-described pressure detection device substrate, the insulating substrate 1 is formed by sintering and integrating the insulating substrate 1b, the spacer 1c, and the diaphragm 1d. The upper surface of the insulating substrate 1b, the lower surface of the spacer 1c, and the like. After forming a frame-like bonding metal layer on the surface and depositing a nickel plating layer having a thickness of about 1 to 10 μm on the surface of the bonding metal layer, these are formed by brazing material such as an Ag—Cu brazing material. The insulating substrate 1 may be formed by joining members together. Such a bonding metal layer can be formed by the same method as that for the electrode conductor layer 2.

  In the pressure detection device of the present invention, as in the example shown in FIG. 6, the electronic component 7 is electrically connected to the electrode conductor layer 2 of the base for the pressure detection device of the present invention having the above-described configuration. According to the pressure detection device of the present invention, the electronic component 7 is electrically connected to the electrode conductor layer 2 of the pressure detection device substrate having the above-described configuration. Therefore, a pressure change from the outside is accurately detected by the pressure detection device base, and an output signal corresponding to the change in capacitance due to the pressure change is processed by the electronic component 7 such as an arithmetic processing unit. Thus, a change in capacitance can be accurately detected as a change in external pressure value.

  When the electronic component 7 such as an arithmetic processing unit is directly connected to the electrode conductor layer 2 via the conductive bonding material 8 as in the example shown in FIG. 6, the same electronic component mounted on the external circuit board Compared with the case where it is connected to 7, the wiring length between the lower electrode 4 and the upper electrode 3 and the electronic component 7 can be shortened, so that the external pressure can be detected with high accuracy. Become. In addition, the pressure sensor module including the pressure detection device and the external circuit board can be reduced in size by using the pressure detection device in which the electronic component 7 is incorporated.

  In the example shown in FIG. 6, the electronic component 7 is a semiconductor element as an arithmetic processing device for performing the arithmetic processing described above, but in addition to this, an electronic device such as a passive element such as a chip capacitor or a chip resistor, an acceleration sensor, or the like. Parts may be mounted.

  In the example shown in FIG. 6, the flip chip type electronic component 7 is bonded to the electrode conductor layer 2 in the recess 1 h via the conductive bonding material 8. Thereby, each electrode of the electronic component 7 and each conductor layer 2 for an electrode are electrically connected, and the electronic component 7 is fixed to the insulating substrate 1. As the conductive bonding material 8 in this case, a solder bump, a gold bump, or a conductive resin (an anisotropic conductive resin or the like) is used. When the electronic component 7 is of the wire bonding type, the electronic component 7 is fixed to the bottom surface of the recess 1h with a bonding material such as glass, resin or brazing material, and then the electronic component 7 is bonded via the bonding wire. The electrode and the electrode conductor layer 2 are electrically connected.

  In the example shown in FIG. 6, the electronic component 7 is sealed in the recess 1h by being covered with a sealing resin 9 such as an epoxy resin. Alternatively, sealing may be performed by bonding a lid (not shown) made of metal or ceramic to the insulating base 1 so as to cover the recess 1h so as to cover the electronic component 7 mounted in the recess 1h. Good.

DESCRIPTION OF SYMBOLS 1 ... Insulating base | substrate 1a ... Internal space 1b ... Insulating substrate 1c ... Spacer 1d ... Diaphragm 1e ... Flexible area 1f ... Wiring conductor 1g ... Frame 1h ... -Recess 1i ... Notch-like recess 2 ... Electrode conductor layer 3 ... Upper electrode 4 ... Lower electrode 5 ... Insulating layer 6 ... Detection electrode 6a ... Detection Electrode wiring 7 ... Electronic component 8 ... Conductive bonding material 9 ... Sealing resin

Claims (2)

  An insulating base made of ceramics having a plurality of electrode conductor layers on the surface, the inner space having an upper surface and a lower surface facing each other in parallel; and the electrode conductor layers on the upper surface and the lower surface of the internal space, respectively. An upper electrode and a lower electrode facing each other and electrically connected to at least one; and an insulating layer covering the upper electrode or the lower electrode; and at least one of the upper surface and the lower surface Is a base for a pressure detection device, which is a flexible region that is bent when pressure is applied from the outside, and the upper electrode and the lower electrode are formed on the surface of the insulating layer corresponding to the central portion of the flexible region. And a detection electrode for detecting contact with the upper electrode or the lower electrode that is electrically independent of the insulating layer and not covered with the insulating layer. Detection device for the substrate.   An electronic component is electrically connected to the electrode conductor layer of the base for a pressure detection device according to claim 1.

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