JP2011095018A - Substrate for pressure detection device, and pressure detection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a base for a pressure detection device and a pressure detection device which can detect an external pressure with high accuracy and have excellent reliability.
SOLUTION: An insulating base 1 having an inner space 1a whose upper surface is a flexible region 1e and having a recess 1h for mounting an electronic component, and a plurality of electrode conductor layers 2 formed on the bottom surface of the recess 1a. An upper electrode 3 and a lower electrode 4 connected to at least one of the electrode conductor layers 2 on the upper and lower surfaces of the internal space 1a, and a plurality of external electrodes 5 formed on the side surface or the lower surface of the insulating base 1. And a base for a pressure detection device provided with a groove 6 provided in a portion corresponding to the periphery of the bottom surface of the recess 1a on the outer surface of the side wall of the recess 1a. Even when the side wall portion around the recess 1 a of the insulating base 1 is pulled from the external circuit board, the side wall portion below the groove 6 is deformed and the insulating base 1 above the groove 6 is prevented from being deformed. Is done.
[Selection] Figure 1

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 which is bonded to the surface of the insulating substrate in a flexible state with a space and is formed with a second electrode for forming a capacitance so as to face the first electrode; One having a recess for mounting an electronic component at the center of the lower surface of the insulating substrate is 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 capacitance type pressure sensing device substrate, there is no inflection point where the diaphragm protrudes from the opposite side of the insulating substrate side to the insulating substrate side due to a change in external pressure. In order to increase the sensitivity of the pressure detection device by reducing the distance between the first electrode and the second electrode, the diaphragm is bent in advance so as to protrude toward the first electrode. There may be. (For example, see Patent Document 2).

  In addition, the pressure detection device is mounted on an external circuit board by bonding external electrodes formed on the lower surface and the outer surface of the side wall portion around the recess with solder or the like (see, for example, Patent Document 3). As the external circuit substrate, one having a coefficient of thermal expansion larger than that of an insulating substrate made of ceramics, for example, a substrate made of glass epoxy resin is usually used.

JP 2007-171053 JP2003-130744 JP2003-207407

  However, when the thermal expansion coefficients of the pressure detection device and the external circuit board are different, if the ambient temperature changes during use of the pressure detection device, the thermal expansion between the insulating substrate of the pressure detection device and the external circuit board will occur. In some cases, the insulating base of the pressure detection device is bent due to the difference in thermal contraction or the difference in thermal shrinkage, and the distance between the first electrode and the second electrode is changed. For this reason, even when the external pressure has not changed, the detected capacitance changes due to a change in ambient temperature, so that the external pressure cannot be accurately detected. It was.

  This is because the thickness of the insulating substrate and the thickness of the diaphragm are becoming thinner as the pressure detection device is made thinner, and the pressure detection device is more easily bent. This was due to bending. That is, if the coefficient of thermal expansion of the external circuit board is larger than that of the insulating substrate, the external circuit board shrinks more than the insulating substrate when the temperature around the pressure detecting device is lowered. Since the surrounding side wall portion is pulled from the external circuit board toward the center of the pressure detection device in plan view, the insulating base of the pressure detection device tends to be deformed so as to be convex on the side opposite to the external circuit board side. At this time, since the diaphragm approaches a state in which the diaphragm protrudes toward the opposite side of the first electrode side from a state in which the diaphragm protrudes toward the first electrode side, the distance between the first electrode and the second electrode increases. The detected capacitance will change.

  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 base for a pressure detection device according to the present invention has upper and lower surfaces facing each other in parallel at the center of the upper surface, and the upper surface has an internal space that is a flexible region that is bent when pressure is applied from the outside, and the lower surface. An insulating base made of ceramics having a recess for mounting an electronic component at the center of the substrate, a plurality of electrode conductor layers formed on the bottom surface of the recess, and the upper surface and the lower surface of the internal space, respectively An upper electrode and a lower electrode facing each other, formed electrically connected to at least one of the electrode conductor layers, and formed on at least one of a side surface or a lower surface of the insulating base, the upper electrode or the lower electrode And a plurality of external electrodes electrically connected to the electrode conductor layer not connected to the side electrode, wherein the insulating base is a side wall portion of the recess. On the outer surface, it is characterized in that it comprises a groove provided in the portion corresponding to the periphery of the bottom surface of the recess.

  Moreover, the base for a pressure detection device according to the present invention is characterized in that, in the above configuration, the groove is connected all around the outer periphery of the side wall portion.

  In the pressure detection device substrate of the present invention, in each of the above-described configurations, the insulating substrate has a quadrangular shape in a plan view, and the grooves are formed through the four corners of the side wall so as to penetrate to the recess. It is characterized by being.

  In the pressure detection device of the present invention, an electronic component is housed in the concave portion of the pressure detection device base body having the above-described configuration, and the electronic component is electrically connected to the electrode conductor layer. It is what.

  According to the base for a pressure detection device of the present invention, the insulating base is provided with a groove provided in a portion corresponding to the periphery of the bottom of the recess on the outer surface of the side wall of the recess. When mounted on an external circuit board and used, when the ambient temperature changes, for example, when the temperature is lowered, the side wall portion around the recess of the insulating substrate faces toward the center of the pressure detection device in plan view. Even when pulled from the external circuit board, the side wall portion below the groove is deformed, and the insulating base above the groove is prevented from being deformed. It can suppress that the space | interval of an electrode and a lower electrode changes. Therefore, since it is possible to suppress the detected capacitance from changing due to a change in ambient temperature, the pressure sensing device base body can accurately detect the external pressure.

  Further, according to the pressure detecting device substrate of the present invention, in the above configuration, when the groove is connected all around the outer periphery of the side wall, the side wall can be obtained even when the ambient temperature changes as described above. By providing the groove connected to the entire circumference of the outer periphery of the part, the side wall part below the groove is deformed better, so that the insulating base above the groove can be further prevented from being deformed.

  According to the pressure detection device substrate of the present invention, in the above configuration, the insulating substrate has a quadrangular shape in a plan view, and grooves are formed through the four corners of the side wall to the recess. In this case, even when the ambient temperature changes as described above, the grooves are formed larger at the four corners where the difference in thermal expansion between the external circuit board and the insulating base is the largest. Since the lower side wall portion is more greatly deformed, it is possible to further suppress deformation of the insulating base above the groove.

  According to the pressure detection device of the present invention, the electronic component is housed in the concave portion of the pressure detection device base body having the above-described configuration, and the electronic component is electrically connected to the electrode conductor layer. By accurately detecting changes in pressure from the outside with the substrate for processing and processing output signals according to changes in capacitance due to changes in pressure with electronic components, the change in capacitance can be detected by the external pressure value. It can be accurately detected as a change.

(A) is a top view which shows an example of embodiment of the base | substrate for pressure detection apparatuses of this invention, (b) is a bottom view which shows an example of embodiment of the base | substrate for pressure detection apparatuses of (a). . (A) is a side view which shows an example of the side surface in the A direction of FIG.1 (b), (b) is sectional drawing which shows an example of the cross section in the BB line of FIG.1 (b). (A) is a bottom view which shows an example of embodiment of the base | substrate for pressure detection apparatuses of this invention, (b) is sectional drawing which shows an example of the cross section in the BB line of (a). (A) is a bottom view which shows an example of embodiment of the base | substrate for pressure detection apparatuses of this invention, (b) is sectional drawing which shows an example of the cross section in the BB line of (a). 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 notched recess, 2 is an electrode conductor layer, 3 is an upper electrode, 4 is a lower electrode, 5 is an external electrode, 6 is a groove, 7 is an electronic component, 8 is a conductive bonding material, and 9 is a seal. It is a stop resin.

  The base for a pressure detection device of the present invention has upper and lower surfaces facing each other in parallel at the center of the upper surface as in the examples shown in FIGS. 1 to 4, and the upper surface bends when pressure is applied from the outside. Insulating base 1 made of ceramics having inner space 1a which is flexible region 1e and having recess 1h for mounting electronic component 6 at the center of the lower surface, and a plurality of electrodes formed on the bottom surface of recess 1h A conductive layer 2, an upper electrode 3 and a lower electrode 4 that are electrically connected to at least one of the electrode conductive layers 2 on the upper and lower surfaces of the internal space 1a, respectively, and a recess 1h. And a plurality of external electrodes 5 that are electrically connected to the electrode conductor layer 2 that is not connected to the upper electrode 3 or the lower electrode 4. . And the insulating base | substrate 1 is equipped with the groove | channel 6 provided in the site | part corresponding to the circumference | surroundings of the bottom face of the recessed part 1h in the outer surface of the side wall part of the recessed part 1h.

  In the example shown in FIGS. 1, 3 and 4, the insulating substrate 1 is formed in a square shape in plan view, the flexible region 1e of the diaphragm 1d is formed in a circular shape in plan view, and the recess 1h is formed in a square shape in plan view. ing. Further, a plurality of external electrodes 5 are provided from the side surface of the insulating base 1, here, from the outer surface of the side wall portion of the recess 1 h to the lower surface of the side wall portion which is the lower surface of the insulating base 1. 1B, FIG. 3A, and FIG. 4A, the groove 6 has a depth that is at least half the thickness of the side wall portion in the direction from the outer wall surface of the insulating substrate 1 to the recess 1h. It is formed as shown in FIG. In the example shown in FIG. 1B, a plurality of grooves 6 are provided so as to overlap each of the plurality of external electrodes 5 in plan view. In the example shown in FIG. 3A, a plurality of external electrodes 5 are provided on the outer surface and the lower surface of the side wall portion of the recess 1h, and the groove 6 overlaps all of the plurality of external electrodes in plan view. It is connected over the entire circumference of the outer periphery of the side wall portion so as to surround the recess 1h. Further, in the example shown in FIG. 4A, the groove 6 is provided so as to surround all of the plurality of external electrodes in a plan view so as to surround the entire periphery of the outer periphery of the side wall and surround the recess 1h. In addition, each of the four corners of the side wall is provided so as to penetrate to the recess 1h.

  According to such a pressure detection device substrate of the present invention, when the pressure detection device is mounted on an external circuit board and used, when the ambient temperature changes, for example, when the temperature drops, the insulating substrate 1 Even when the side wall portion around the recess 1h is pulled from the external circuit board toward the center of the pressure detection device in plan view, the side wall portion below the groove 6 is deformed, and the insulation above the groove 6 is insulated. Since the deformation of the base body 1 is suppressed, the deformation of the diaphragm 1d is suppressed and the change between the upper electrode 3 and the lower electrode 4 can be suppressed. Moreover, since the groove 6 is provided in a portion corresponding to the periphery of the bottom surface of the concave portion 1h on the outer side surface of the side wall portion of the concave portion 1h, the length of the deformed side wall portion below the groove 6 can be ensured. .

  Further, in the above example, since the groove 6 is provided at a position overlapping the external electrode 5 in plan view, the distance between the external electrode 5 and the groove 6 pulled from the external circuit board is the shortest, and is larger than the groove 6. The lower side wall part is easily deformed. Therefore, since it is possible to suppress the detected capacitance from changing due to a change in ambient temperature, the pressure sensing device base body can accurately detect the external pressure.

  Further, as in the example shown in FIG. 3, when the groove 6 is connected all around the outer periphery of the side wall, even when the temperature is lowered when the pressure detection device is mounted on the external circuit board and used, Since the side wall portion below the groove 6 is more easily deformed, it is possible to better suppress the deformation of the insulating substrate 1 above the groove 6.

  Further, as in the example shown in FIG. 4, when the insulating base 1 has a quadrangular shape in a plan view and the grooves 6 are formed through the recesses 1 h at the four corners of the side wall, Since the groove 6 is formed larger at the four corners where the difference in thermal expansion from the insulating base 1 is the largest, the side wall portion below the groove 6 becomes more deformed at the four corners. It is possible to better suppress the deformation of the insulating base above the groove 6.

  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 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.

  In addition, the insulating base 1 is formed with a recess 1h for housing an electronic component (not shown) on the lower surface of the insulating base 1 opposite to the upper surface where the flexible region 1e is formed. Functions as a container for housing electronic components and protecting the electronic components.

  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, in the ceramic green sheet for the spacer 1c, through-holes that become the internal space 1a and the recess 1h 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 1a and the recess 1h is formed. Then, by firing this ceramic green sheet laminate at a temperature of about 1600 ° C., an insulating substrate 1 having an internal space 1a and a recess 1h is manufactured.

  In addition, the insulating base 1 may include a frame 1g on the outer peripheral portion of the diaphragm 1d as in the example shown in FIGS. 3B and 4B. The frame 1g has a frame-like shape similar to the spacer 1c, which is laminated and integrated 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 sandwiched and formed, diaphragm 1d warpage during firing 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 is used as a terminal electrode for transmitting a change in capacitance between the upper electrode 3 and the lower electrode 4 as an electrical signal to the electronic component, or an electrical processed by the electronic component. Functioning as a terminal electrode for transmitting a simple signal to the external electrode 5, between the electrode conductor layer 2 and the upper electrode 3 and the lower electrode 4, and between the electrode conductor layer 2 and the external electrode 5. The space is electrically connected by a wiring conductor 1 f formed inside the insulating substrate 1.

  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 (see FIG. 2B). In the example shown, the upper electrode 3 is attached to the lower surface of the diaphragm 1 d so as to face the lower electrode 4. The lower electrode 4 and the upper electrode 3 are electrodes for forming a capacitance. Between these, an area where the lower electrode 4 and the upper electrode 3 face each other and an interval between the lower electrode 4 and the upper electrode 3 are set. A corresponding capacitance is formed. In the example shown in FIG. 2, when pressure is applied to the insulating base 1 from the outside, the flexible region 1 e of the diaphragm 1 d bends toward the insulating substrate 1 b in accordance with the pressure, and the lower electrode 4 and the upper electrode 3 Since the interval changes (becomes smaller) and the capacitance between the lower electrode 4 and the upper electrode 3 changes (becomes larger), the change in external pressure can be detected by detecting this change in capacitance. It functions as a pressure detection device that detects a change 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.

  Then, this change in electrostatic capacitance is detected as an electrical signal through the electrode conductor layer 2 and is processed by an electronic component such as an arithmetic processing device mounted in the recess 1h. You can know the size and change.

  The external electrode 5 functions as a terminal electrode for transmitting an electrical signal calculated by an electronic component to an external circuit board. The external electrode 5 is formed on at least one of the side surface or the lower surface of the insulating substrate 1, for example, the outer surface of the side wall portion of the recess 1h or the lower surface of the side wall portion. In the example shown in FIGS. 1 to 4, a plurality of external electrodes 5 are provided from the outer surface of the side wall portion of the recess 1 h to the lower surface of the side wall portion. That is, a notch-shaped recess 1i is formed on the side surface of the insulating base 1, and an external electrode 5 that functions as a terminal electrode is provided as a so-called castellation conductor on the inner surface of the notch-shaped recess 1i.

  The electrode conductor layer 2, the upper electrode 3, the lower electrode 4, the external electrode 5, and the wiring conductor 1 f are made of a metallized conductor using a metal powder such as tungsten, molybdenum, copper, silver, etc. For example, the insulating substrate 1 is oxidized In the case of an aluminum sintered body, a metallized paste obtained by adding and mixing an appropriate organic binder, a solvent, a plasticizer, a dispersant, etc. to a metal powder such as tungsten is used for the insulating substrate 1 by screen printing. The ceramic green sheet is printed and applied in a predetermined pattern, and is fired together with the ceramic green sheet laminate for the insulating substrate 1 to form a predetermined pattern in and on 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.

  Further, as in the example shown in FIG. 3A, the wiring conductor 1f may be exposed on the inner wall surface of the recess 1h. In such a wiring conductor 1f, after filling the through hole of the ceramic green sheet with the metallized paste for the wiring conductor 1f, the through hole serving as the recess 1h is punched out so that the filled metallized paste is exposed on the inner wall surface side. Formed by. Thereby, compared with the case where the wiring conductor 1f is formed between the side wall portions, the interval between the wiring conductor 1f and the outer wall surface of the side wall portion can be increased, and the possibility of cracks occurring in the side wall portions is reduced. can do.

  The spacer 1c functions as providing a predetermined gap 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, and has a through hole that forms the internal space 1a. It is formed in a shape. When the spacer 1c has a thickness of 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. It becomes difficult to detect. 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. Becomes smaller and the sensitivity becomes lower. 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. In addition, if the thickness of the diaphragm 1d is less than 0.01 mm, its mechanical strength becomes small, and it becomes difficult to produce it using the above-described ceramic green sheet. On the other hand, when it exceeds 1 mm, it becomes difficult to bend with a small pressure, and it becomes 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.

  And the insulating base | substrate 1 is equipped with the groove | channel 6 provided in the site | part corresponding to the circumference | surroundings of the bottom face of the recessed part 1h in the outer surface of the side wall part of the recessed part 1h. The grooves 6 are formed in some of the ceramic green sheets for the insulating substrate 1b by forming through holes to be the grooves 6 by a punching method such as a die or punching or laser processing, and then other insulation. It is formed by laminating with a ceramic green sheet for the substrate 1.

  If the groove 6 is provided in a plurality of portions corresponding to the periphery of the bottom surface of the recess 1h as in the example shown in FIG. 1, the shape thereof is semicircular, oval or elliptical in plan view. Is formed into a polygonal shape such as a semicircular shape, a triangular shape, or a quadrangular shape. Especially, in order to absorb a stress favorably by the groove | channel 6, it is preferable that it is a semicircle shape which does not have a corner | angular part on an inner surface.

  If the dimensions of the insulating substrate 1 are 5 mm to 15 mm in length, 5 mm to 15 mm in width, 2 mm to 5 mm in thickness, and 0.5 mm to 1 mm in thickness of the side wall, the groove 6 has a height of 0.01 mm to When the shape is about 1 mm, the radius is about 0.25 mm to 0.7 mm when the shape is semicircular, and when the shape is a semicircular shape, a triangular shape, or a quadrangular shape obtained by dividing an oval or an ellipse into two equal parts It is preferable that the width is about 0.2 mm to 1.0 mm and the longest depth is about 0.25 mm to 0.5 mm. Moreover, it is preferable that the total area when such a groove 6 is viewed in plan is about 15 to 70% of the area when the side wall of the recess 1h is viewed in plan.

  For example, if the dimensions of the insulating substrate 1 are 5 mm in length, 5 mm in width, 2 mm in thickness, and 0.5 mm in thickness on the side wall, the groove 6 has a height of 0.01 mm and a semicircular shape. In this case, the radius is 0.25 mm, and in the case of a semicircular shape obtained by dividing an oval or an ellipse into two equal parts, a triangular shape or a quadrangular shape, the width is about 0.2 mm, and the longest depth is 0.25 mm. If the dimensions of the insulating substrate 1 are 15 mm in length, 15 mm in width, 5 mm in thickness, and 1 mm in thickness on the side wall, the groove 6 has a height of 1 mm and a semicircular shape. In this case, the radius is 0.5 mm, and in the case of a semicircular shape obtained by dividing an oval or an ellipse into two equal parts, a triangular shape or a quadrangular shape, the width is 1.0 mm, and the longest depth is 0.5 mm.

  If a plurality of grooves 6 are formed, the interval between the grooves 6 is preferably set to 0.2 mm or more. When the interval between the adjacent grooves 6 is set to 0.2 mm or more, it is possible to suppress the occurrence of cracks between the adjacent grooves 6 during the manufacturing process.

  Moreover, it is preferable that the space | interval of the groove | channel 6 and the recessed part 1h shall be 0.2 mm or more. When the distance between the groove 6 and the recess 1h is set to 0.2 mm or more, it is possible to suppress the occurrence of cracks between the groove 6 and the recess 1h during the manufacturing process.

  Further, as in the example shown in FIGS. 3 and 4, the grooves 6 are preferably connected all around. In such a case, when the pressure detection device is mounted on an external circuit board and used, the side wall portion around the recess 1h of the insulating base 1 is in the center of the pressure detection device in plan view due to a change in ambient temperature. Even when it is pulled from the external circuit board, the side wall portion below the groove 6 is more easily deformed, so that it is possible to better suppress the deformation of the insulating substrate 1 above the groove 6.

  The groove 6 is preferably provided at a position overlapping the external electrode 5 in plan view as in the example shown in FIGS. 1B, 3A, and 4A. At this time, since the distance between the external electrode 5 pulled from the external circuit board and the groove 6 becomes short, the stress applied to the insulating layer 1 above the groove 6 is further blocked by the external electrode 5 being pulled. be able to.

  In addition, when the insulating substrate 1 has a quadrangular shape in a plan view and the external electrodes 5 are provided in each of the four corners of the side wall, the grooves 6 provided in the four corners are divided into four grooves 6. You may form larger than the groove | channel 6 provided in parts other than a corner | angular part. In this case, the distance between the four corners where the distance between the wiring conductors of the external circuit board and the external terminals of the insulating base is the longest and the difference in thermal expansion between the external circuit board and the insulating base is the largest. In this case, since the side wall portion below the groove 6 is deformed better, it is possible to better suppress the deformation of the insulating base above the groove 6.

  Further, when the insulating substrate 1 is manufactured, the groove 6 of the ceramic green sheet laminate for the insulating substrate 1 may be filled with a burned-out member that is burned out by the end of firing. When the burning member is filled in the groove 6, the groove 6 of the ceramic green sheet laminate for the insulating substrate 1 is supported by the burning member, so when handling the ceramic green sheet laminate for the insulating substrate 1, It can suppress that the ceramic green sheet laminated body for insulating base | substrates 1 deform | transforms with the groove | channel 6. FIG. Moreover, it is possible to prevent the grooves 6 from being deformed when a plurality of ceramic green sheets for the insulating base 1 are laminated by applying pressure. Note that the burned-out member is thermally decomposed into a gas when fired, and is discharged from the opening of the groove 6.

  Further, as in the example shown in FIG. 4, if the groove 6 is formed so as to penetrate from the notch-shaped recess 1 i to the recess 1 h, when the ceramic green sheet laminate for the insulating substrate 1 is fired, Since the vanishing member is thermally decomposed into gas, the vanishing member that has become gas passes through the recess 1 h or the groove 6 and is well discharged from the notch-shaped recess 1 i, thereby suppressing deformation of the groove 6. Can do.

  As such a burned-out member, for example, a resin sheet or a resin paste in which acrylic resin beads and an acrylic binder are dispersed and mixed using an organic solvent and thermally decomposed during firing can be used. The resin sheet is overlaid on the ceramic green sheet for the insulating substrate 1b and punched out by a mold to form a through hole serving as the groove 6 in the ceramic green sheet for the insulating substrate 1b. The resin sheet is formed in the through hole. As a result, the resin sheet is filled in the groove 6 of the ceramic green sheet laminate for the insulating substrate 1. Alternatively, by forming a recess to be the groove 6 in the ceramic green sheet for the insulating substrate 1b, and printing and filling the resin paste in the recess by a screen printing method or the like, then laminating the ceramic green sheet for the diaphragm 1d, A resin paste may be filled in the groove 6 of the ceramic green sheet laminate for the insulating substrate 1.

  Further, a through hole having the same size as the outer periphery of the side wall portion is formed in the resin sheet, and a ceramic green sheet for the insulating substrate 1b is embedded in the through hole to form a composite sheet. After forming the through hole that becomes the recess 1h, the ceramic green sheet laminated body for the insulating substrate 1 may be formed by laminating with other ceramic green sheets for the insulating substrate 1. In this case, it is possible to easily form the insulating substrate 1 in which the grooves 6 are connected to one as shown in the example shown in FIGS.

  The lower electrode 4 is preferably smaller than the upper electrode 3 and at a position that does not protrude from the upper electrode 3 in plan view. Furthermore, when the sizes of the upper electrode 3 and the lower electrode 4 are made different, it is preferable that the smaller one is positioned so as not to protrude from the larger one in plan view. With such a configuration, even when the opposing positions of the upper electrode 3 and the lower electrode 4 are shifted when the insulating substrate 1 is manufactured, the area where the upper electrode 3 and the lower electrode 4 are opposed does not change. preferable. Further, the rate of change of the inter-electrode distance between the upper electrode 3 and the lower electrode 4 due to the fluctuation of the external pressure in the flexible region 1e is the central side in the plane direction of the internal space 1a (the central side of the flexible region 1e). It is large and small on the outer peripheral side of the internal space 1a (the outer peripheral side of the flexible region 1e). Therefore, when the electrode provided on the insulating substrate 1b side is smaller than the flexible region 1e, the upper electrode 3 and the lower electrode 4 can be opposed to each other on the center side of the flexible region 1e where the change rate of the interelectrode distance is large. As a result, the rate of change in capacitance due to the application of external pressure increases, and the sensitivity of the pressure detection device can be increased.

  The upper electrode 3 or the lower electrode 4 may be covered with an insulating layer (not shown) made of a ceramic sintered body on at least one of the surfaces facing each other. At this time, even if the diaphragm 1d is greatly bent due to a large pressure and the upper electrode 3 and the lower electrode 4 come into contact with each other, it is possible to prevent both from being short-circuited. For example, when the lower electrode 4 is smaller than the lower surface of the internal space 1a, the insulating layer may cover only the surface of the lower electrode 4 or from the surface of the lower electrode 4 to the periphery thereof. The inner space 1a may be covered over the lower surface. In addition, it is preferable to use the same insulating layer as that of the insulating substrate 1 because it can be formed by simultaneous firing.

  For example, in the case of the example shown in FIG. 2, such an insulating layer is formed on the metallized paste for the lower electrode 4 printed on the ceramic green sheet for the insulating substrate 1 b by screen printing or the like. Thus, the ceramic paste for the insulating layer can be printed and applied, and simultaneously fired with the ceramic green sheet laminate for the insulating substrate 1. Ceramic paste for insulating layer is mixed and kneaded by kneading means such as ball mill, three roll mill or planetary mixer, adding organic binder and organic solvent to main component ceramic powder, and dispersing agent if necessary Is produced. Alternatively, it can be formed by laminating a ceramic green sheet for an insulating layer on a ceramic green sheet on which a metallized paste for the lower electrode 4 is printed. In addition, when forming an insulating layer with a ceramic green sheet, since the thickness dispersion | variation of an insulating layer can be reduced compared with the case where it forms by printing a ceramic paste, it is between the upper electrode 3 and the lower electrode 4. A base for a pressure detection device with small variations in relative permittivity can be obtained.

  The exposed surfaces of the electrode conductor layer 2 and the external electrode 5 are for preventing the electrode conductor layer 2 and the external electrode 5 from being oxidatively corroded and for joining the electrode conductor layer 2 and the electronic component. And a nickel plating layer having a thickness of about 1 to 10 μm and a thickness of the outer electrode 5 and the conductive conductor such as solder for joining the wiring conductor of the external circuit board. A gold plating layer of about 0.1 to 3 μm is sequentially deposited by an electroless plating method or an electrolytic plating method.

  As shown in the example shown in FIG. 5, the pressure detection device of the present invention has the electronic component 7 accommodated in the recess 1h of the pressure detection device base body of the present invention having the above-described configuration, Electrically connected. According to the pressure detection device of the present invention, a change in electrostatic capacitance formed between the lower electrode 4 and the upper electrode 3 is electrically transmitted to the electronic component 7 via the wiring conductor 1f and the electrode conductor layer 2. An external pressure value and its change can be detected by transmitting it as a signal and processing it with an electronic component 7 such as a processing device. 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, it is compared with the case where it is connected to the same electronic component 7 mounted on the external circuit board. Since the wiring length between the lower electrode 4 and the upper electrode 3 and the electronic component 7 can be shortened, the external pressure can be detected with high accuracy. 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. 5, 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, a passive element such as a chip capacitor or a chip resistor, an acceleration sensor, or the like Electronic components may be mounted.

  In the example shown in FIG. 5, 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. 5, the electronic component 7 is sealed in the recess 1h by being covered with a sealing resin 9 such as an epoxy resin. In addition to this, the electronic component 7 is bonded to the insulating base 1 with a lid (not shown) made of metal or ceramic so as to cover the concave portion 1h so as to cover the electronic component 7 mounted in the concave portion 1h. You may seal by doing.

  A specific example of the base for a pressure detection device of the present invention will be described by taking an example of the embodiment of the base for a pressure detection device shown in FIGS. 1, 3 and 4 as an example.

  First, as Example 1 to Example 3 of the present invention, an aluminum oxide sintered body having a length of 6.98 mm, a width of 6.98 mm, and a thickness of 3.9 mm is formed, and the lower surface has a length of 5.68 mm, a width of 5.68 mm, and a depth of 0.70 mm. Insulating base 1 provided with a recess 1h (insulating substrate 1b thickness: 3.3 mm, spacer 1c thickness: 0.35 mm, diaphragm 1d thickness: 0.10 mm, frame body 1g thickness: 0.15 mm, frame body 1g opened) (Caliber: 4.35 mm) was prepared. The flexible region 1e was formed in a circular shape with a diameter of 4.15 mm at the center of the diaphragm 1d.

  Further, a total of 16 external electrodes 5 were provided on the side walls of the recess 1 h of the insulating substrate 1 on four sides and four corners. That is, three semicircular cutout recesses 1i (radius 0.3 mm × height 0.65 mm) are provided on each of the four sides, and the side walls of the recesses 1h from the inner peripheral surface of the cutout recesses 1i. The external electrode 5 was formed over the lower surface of the part. Further, an external electrode is formed on each of the four corners from the inner peripheral surface of the fan-shaped notched recess 1i (radius 0.3 mm × height 0.65 mm) having a central angle of 90 ° to the lower surface of the side wall of the recess 1h. 5 was formed.

  In Embodiments 1 to 3, the groove 6 is formed along the outer surface of the side wall portion 0.65 mm from the lower surface, corresponding to the periphery of the bottom surface of the recess 1 h of the insulating base 1. did. In the first embodiment, as in the example shown in FIGS. 1 and 2, three semicircular grooves 6 (radius 0.35 mm × height 0.05 mm) on each of the four sides and four corners respectively. The fan-shaped groove 6 (radius 0.35 mm × height 0.05 mm) having a central angle of 90 ° is positioned above the external electrode 5 in a region overlapping with each external electrode 5 when viewed in plan. Formed.

  Next, in Example 2, when the groove 6 (depth 0.65 mm × height 0.05 mm) formed through the four corners up to the recess 1 h is viewed in a plan view as in the example shown in FIG. 4. In the region overlapping with each of the external electrodes 5, it was formed so as to be positioned above the external electrode 5.

  Further, in Example 3, as in the example shown in FIG. 3, one groove 6 (depth 0.35 mm × height 0.05 mm) formed so as to be connected over the entire circumference of the outer surface of the side wall portion is provided as the external electrode 5. It was formed so as to be located above.

  In addition, as a comparative example, a base for a pressure detection device having the same configuration as in Examples 1 to 3 except that the groove 6 was not provided was manufactured.

Next, mounting electrodes made of copper foil were formed on the FR-4 substrate (thermal expansion coefficient: 13 × 10 ⁻⁶ / ° C.) from the substrates for pressure detection devices of Examples 1 to 3 and Comparative Example. The external circuit board was mounted with a lead-tin eutectic solder, and the capacitance at 25 ° C. was measured. Then, it cooled to 0 degreeC in the constant pressure environment, and measured the electrostatic capacitance in 0 degreeC.

  As a result, the amount of change in the capacitance value at 0 ° C. with respect to the capacitance value at 25 ° C. was 10 fF in the comparative example, whereas 1 fF in Example 1 and 4 fF in Example 2. Example 3 was 4 fF, both of which were small. From this result, it is understood that the deformation of the diaphragm 1d is suppressed by the groove 6 and the change amount of the capacitance value is reduced.

In addition, for the pressure detection device substrates of Examples 1 to 3 and the comparative example, the thermal expansion coefficient of the insulating substrate 1 is 7 × 10 ⁻⁶ / ° C., and the thermal expansion coefficient of the external circuit board is 13 × 10 ^{− The} stress applied to the spacer 1c when the temperature was changed from 25 ° C. to −20 ° C. as ⁶ / ° C. was obtained by simulation.

As a result, in the comparative example, the stress applied to the spacer 1c was 1.95 × 10 ⁻¹ 1.91 N / mm ² . In contrast, in Example 1, the stress applied to the spacer 1c was 5.01 × 10 ⁻¹ N / mm ² , which was 26.2% of the stress in the comparative example. In Example 2, the stress applied to the spacer 1c was 6.15 × 10 ⁻¹ N / mm ² , which was 32.2% of the stress in the comparative example. In Example 3, the stress applied to the spacer 1c was 6.10 × 10 ⁻¹ N / mm ² , which was 3.19% of the stress in the comparative example. As a result, according to the pressure detecting device substrate of the present invention, it was confirmed that the stress applied to the spacer 1c was reduced by providing the groove 6 along the outer surface of the side wall portion of the insulating substrate 1.

  From the above results, according to the pressure detection device substrate, since the groove 6 is provided, the deformation of the insulating substrate 1 above the groove 6 is suppressed, so that the deformation of the diaphragm 1d is suppressed. In other words, it can be said that the change in the distance between the upper electrode 3 and the lower electrode 4 can be suppressed. Accordingly, since the capacitance detected by the pressure detection device can be suppressed from changing due to a change in ambient temperature, the pressure detection device substrate can accurately detect the external pressure.

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-shaped recess 2 ... Electrode conductor layer 3 ... Upper electrode 4 ... Lower electrode 5 ... External electrode 6 ... Groove 6a ... Through hole 7 ... Electronic component 8 ... Conductive bonding material 9 ... Sealing resin

Claims (4)

  At the center of the upper surface, there are upper and lower surfaces facing each other in parallel, and the upper surface has an internal space that is a flexible region that is bent when pressure is applied from the outside, and an electronic component is mounted at the center of the lower surface And a plurality of electrode conductor layers formed on the bottom surface of the recess, and at least one of the electrode conductor layers on the upper surface and the lower surface of the internal space. The upper electrode and the lower electrode facing each other, and the electrode formed on at least one of the side surface or the lower surface of the insulating base and not connected to the upper electrode or the lower electrode. A base for a pressure detection device comprising a plurality of external electrodes electrically connected to a conductor layer, wherein the insulating base is formed on the outer surface of the side wall of the recess and on the bottom surface of the recess. Pressure detecting apparatus for a substrate, characterized in that it comprises a groove provided in the portion corresponding to the periphery.   The base for a pressure detection device according to claim 1, wherein the groove is connected all around the outer periphery of the side wall.   The said insulating base | substrate is square shape by planar view, The said groove | channel is penetrated and formed in the four corner | angular parts of the said side wall part, The Claim 1 or Claim 2 characterized by the above-mentioned. Substrate for pressure detection device.   An electronic component is housed in the recess of the pressure detection device base according to any one of claims 1 to 3, and the electronic component is electrically connected to the electrode conductor layer. Pressure detector.

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