JP6602744B2 - Sensor device and manufacturing method thereof - Google Patents

Description

  The present invention relates to a sensor device that measures a physical quantity such as an air flow rate or pressure, and more particularly to an air flow sensor that measures an intake air amount of an internal combustion engine.

  Physical quantities such as air flow rate and pressure are widely used as important control parameters in various devices, and sensors that measure these physical quantities are one of the important components that affect the performance of the devices. For example, a vehicle equipped with an internal combustion engine has a very high demand for fuel saving and exhaust gas purification. In order to meet these demands, an air flow sensor that measures the intake air amount, which is a main parameter of the internal combustion engine, with high accuracy is required.

  A sensor device such as an air flow sensor is manufactured by, for example, mounting a sensor element or an electronic component on a substrate and forming a housing by resin sealing. At this time, since it is necessary to have a structure in which the sensor element is exposed to the outside air in order to measure the air flow rate, the resin is removed by pressing the substrate with a mold in the resin sealing process for forming the housing. It is necessary to have a structure in which the substrate and the sensor are partially exposed. Such a technique is disclosed in, for example, Japanese Patent Application Laid-Open No. 11-15216 (Patent Document 1).

JP-A-11-150216

  In the technique described in Patent Document 1, a semiconductor element is mounted on a heat sink, and the semiconductor element and each lead portion of the lead frame are connected by a bonding wire. A protrusion is formed on the exposed surface of the heat radiating plate so as to continuously extend from the peripheral edge to a position slightly inside the entire circumference. The mold is placed on the lead frame, and the resin is sealed while pressing the heat sink with the mold. At this time, the protrusion of the heat sink is plastically deformed by the pressing of the mold, and is in close contact with the mold, thereby preventing the resin from flowing into the exposed surface of the heat sink and the generation of resin burrs.

  The above technique can be used for a ductile material such as a metal in which a protrusion of a heat sink is plastically deformed by pressing of a mold. On the other hand, when a brittle material such as a printed circuit board or a ceramic substrate is used for the substrate, there is a problem that the substrate is damaged by pressing of the mold. Further, since the substrate has a thickness variation, it is also a problem that the resin burrs and the substrate are damaged when the pressing force of the mold is changed due to the thickness variation. For this reason, in the conventional resin sealing method, it is difficult to seal the resin while partially exposing a part of the printed circuit board or the ceramic substrate.

  An object of the present invention is to provide a highly reliable sensor device in which a sensor element is mounted on a brittle material such as a printed circuit board, and a resin burr and a substrate are prevented from being damaged in a process of resin sealing while exposing the sensor element. Is to provide.

  In order to achieve the above object, a sensor device of the present invention includes a sub-passage that takes in a part of a fluid to be measured, a sensor element disposed in the sub-passage, a substrate on which the sensor element is mounted, and the substrate And a housing having a fixing portion that holds the substrate while forming a part of a wall surface of the sub-passage, and the substrate is formed in a direction along the fixing portion. It has a groove part, and the groove part is formed so that the bottom part may have a field where the substrate is held by the fixed part, and a field which is not so.

  According to the present invention, it is possible to provide a highly reliable sensor device.

It is a top view of the sensor assembly in the 1st example concerning this application. It is a bottom view of the sensor assembly in the 1st example concerning this application. It is sectional drawing of the sensor assembly in 1st Example which concerns on this application. It is a top view of the sensor apparatus in the 1st example concerning this application. It is a bottom view of the sensor apparatus in the 1st example concerning this application. It is sectional drawing of the sensor apparatus in 1st Example which concerns on this application. It is a section enlarged view of the sensor device in the 1st example concerning this application. It is sectional drawing in the resin sealing process of the sensor assembly in 1st Example which concerns on this application. It is a cross-sectional enlarged view in the resin sealing process of the sensor assembly in 1st Example which concerns on this application. It is a top view of the sensor assembly in the 1st example concerning this application. It is a bottom view of the sensor assembly in the 1st example concerning this application. It is a top view of the sensor apparatus in the 1st example concerning this application. It is a bottom view of the sensor apparatus in the 1st example concerning this application. It is sectional drawing of the sensor assembly in 2nd Example which concerns on this application. It is sectional drawing in the resin sealing process of the sensor assembly in 2nd Example which concerns on this application. It is a cross-sectional enlarged view in the resin sealing process of the sensor assembly in 2nd Example which concerns on this application. It is sectional drawing of the sensor assembly in 3rd Example which concerns on this application. It is sectional drawing in the resin sealing process of the sensor assembly in 3rd Example which concerns on this application. It is a cross-sectional enlarged view in the resin sealing process of the sensor assembly in 3rd Example which concerns on this application. It is sectional drawing of the sensor assembly in 4th Example which concerns on this application. It is sectional drawing in the resin sealing process of the sensor assembly in 4th Example which concerns on this application. It is a cross-sectional enlarged view in the resin sealing process of the sensor assembly in 4th Example which concerns on this application. It is sectional drawing of the sensor assembly in 5th Example which concerns on this application. It is sectional drawing in the resin sealing process of the sensor assembly in 5th Example which concerns on this application. It is a cross-sectional enlarged view in the resin sealing process of the sensor assembly in 5th Example which concerns on this application. It is sectional drawing of the sensor assembly in 6th Example based on this application. It is sectional drawing in the resin sealing process of the sensor assembly in 6th Example which concerns on this application. It is a cross-sectional enlarged view in the resin sealing process of the sensor assembly in 6th Example which concerns on this application.

  Embodiments of the present invention will be described below with reference to the drawings.

  First, a first embodiment of the sensor device will be described with reference to FIGS. 1 is a plan view of the sensor assembly 10, FIG. 2 is a bottom view of the sensor assembly 10, and FIG. 3 is a cross-sectional view taken along the line AA in FIG.

  As shown in FIGS. 1 to 3, the sensor assembly 10 is formed by mounting a sensor element 2 and an electronic component 3 that processes a signal of the sensor element 2 on a substrate 1. The substrate 1 may be a ceramic substrate or a printed substrate. The sensor element 2 has a role of measuring a physical quantity of fluid, and examples thereof include a flow rate sensor, a pressure sensor, and a humidity sensor. Examples of the electronic component 3 include an LSI and a microcomputer. Electrical connection is made between the substrate 1 and the sensor chip 2 and between the substrate 1 and the electronic component 3 using solder or bonding wires. For example, if the sensor device is a flow sensor, the air flow is measured by the air 26 passing through the flow rate detector of the sensor element 2 from the direction of the arrow in FIG. The substrate 1 can employ a configuration in which both sides are mounted. In that case, for example, other sensors such as a humidity sensor and a pressure sensor can be mounted on the back surface side.

  4 is a plan view when the sensor assembly 10 is mounted on the housing 5 including the sub-passage 12, and FIG. 5 is a bottom view. 6 is a cross-sectional view taken along line BB in FIG. 4, and FIG. 7 is an enlarged cross-sectional view of FIG. As shown in FIGS. 4 to 6, the housing 5 forms a sub-passage 12 for guiding the air flowing through the main passage to the sensor chip 2 in cooperation with a cover (not shown). The housing 5 and the sensor assembly 10 are integrally molded by resin sealing. The sensor assembly 10 is fixed in a state of being inserted into the housing 5 in the fixing region 4 indicated by the oblique lines in FIG. The resin used for the housing 5 is, for example, a thermoplastic resin. At this time, the sensor element 2 is arranged so as to be exposed in the auxiliary passage 12.

  And the fixed area | region 4 and the groove | channel 6 are formed in the periphery of the board | substrate 1 of the sensor assembly 10 by machining, for example.

  The operation and effect of the first embodiment will be described with reference to FIGS. 8 is a cross-sectional view taken along line AA in FIG. 1 in the resin sealing process of the sensor assembly 10, and FIG. 9 is an enlarged cross-sectional view of FIG.

  When the sensor assembly 10 is fixed to the housing 5, a molding process is adopted. In the molding process, after the substrate 1 of the sensor assembly 10 is installed on the mold 25, it is fixed to the housing 5 by clamping with the mold 25 and sealing with resin. At this time, since the sensor element 2 needs to be exposed in the sub-passage 12, the substrate 1 is sealed with the resin while being pressed by the mold 25 to prevent the resin from flowing into the sub-passage 12. Yes.

  Here, the magnitude of pressing of the mold 25 is determined by the amount by which the mold 25 presses the substrate 1. However, since the thickness 20a of the substrate 1 varies, the pressing force of the mold 25 varies due to the variation. That is, if the thickness 20a of the substrate 1 is smaller than the design median value, the pressing force of the mold 25 is reduced, and if it becomes a certain pressing force or less, the resin flows out into the sub-passage 12. On the other hand, if the thickness 20a of the substrate 1 is larger than the design median value, the pressing force of the mold 25 increases, and if it exceeds a certain pressing force, the substrate 1 is damaged. Therefore, the yield deteriorates due to the variation in the thickness 20a of the substrate 1.

  In the present embodiment, the groove 6 is formed in the fixing region 4 of the housing 5 and the periphery thereof with respect to the substrate 1 by a process having better accuracy than the thickness variation of the substrate 1. Since the mold 25 presses the groove portion 6 of the substrate 1 in the resin sealing step, the variation in the pressing force due to the thickness variation depends on the variation in the thickness 20b between the grooves. The groove 6 is formed by a process having higher accuracy than the thickness variation of the substrate 1, thereby reducing the variation of the pressing portion (groove portion) pressed by the mold to be smaller than the thickness variation of the substrate 1. can do. For example, the groove 6 is formed by machining.

  According to this embodiment, the variation in the thickness 20b between the grooves can be made smaller than the thickness variation 20a of the substrate 1. Therefore, the variation in the pressing force of the mold 25 in the resin sealing process can be reduced, the outflow of resin due to insufficient pressing force and the damage to the substrate 1 due to excessive pressing force can be suppressed, and a more reliable sensor device can be provided.

  The housing 5 has a fixing portion for holding the substrate 1, the substrate 1 has a groove portion formed in a direction along the fixing portion, and the groove portion 6 is held at the bottom portion of the substrate 1 by the fixing portion. It has a region that is and a region that is not.

  In this embodiment, in order to reduce the thickness variation 20a of the substrate 1, the accuracy of the substrate 1 is improved by an accurate subsequent process. In this embodiment, the groove is taken as an example, but the entire surface may naturally be cut.

  A further advantageous effect of using the groove 6 is that even when the resin flows out, the resin is blocked by the groove 6, so that the resin can be prevented from reaching the sensor element 2, and the effect can be achieved in the minimum necessary cutting range. Therefore, the production is easy.

  In the present embodiment, an example in which the groove 6 is used for all of the fixed region 4 is shown, but the present invention is not necessarily limited thereto. In the case where the region where the stress at the time of manufacture is particularly worrisome is the region where the fixing portion is formed while forming the wall surface of the sub-passage 12, the groove 6 may be provided in the fixing region 4. That is, the groove 6 is provided between the sensor 2 and the electronic component 3.

  A modification of the present embodiment will be described with reference to FIGS. 10 is a plan view of the sensor assembly, FIG. 11 is a bottom view, FIG. 12 is a plan view when the sensor assembly 10 is mounted on the housing 5, and FIG. 13 is a bottom view. A different configuration from the previous embodiment is that a plurality of electronic components 3 and 13 and sensor elements 2 and 14 to 16 are installed on the substrate 1. The electronic component is, for example, a microcomputer or LSI, and the sensor element is, for example, a temperature sensor, a pressure sensor, or a humidity sensor. 10 to 13, it goes without saying that the same effects can be obtained even when a plurality of sensor elements 2, 14 to 16 and electronic components 3 and 13 are installed on the substrate 1. FIG.

  A second embodiment of the present invention will be described with reference to FIGS.

  The configuration different from the first embodiment is that the convex portions 7 are formed in the fixed region by forming grooves 6 at both ends of the fixed region 4 of the housing 5 with respect to the substrate 1. As shown in FIG. 16, the housing 5 is formed on the convex portion 7 of the substrate 1, whereby the fixing force between the substrate 1 and the housing 5 is increased, and a more reliable sensor device can be provided. Similarly to the first embodiment, the housing 5 has a fixing portion for holding the substrate 1, the substrate 1 has a groove portion formed in a direction along the fixing portion, and the groove portion 6 has a bottom portion thereof. However, since the board | substrate 1 has the area | region where the board | substrate 1 is hold | maintained at a fixing | fixed part, and the area | region which is not so, the metal mold pressing part at the time of manufacture can be made into a groove part, and manufacturing dispersion | variation can be suppressed.

  Next, a third embodiment of the present invention will be described with reference to FIGS.

  A different configuration from the previous embodiment is that the surface is roughened by forming the grooves 6 on the substrate 1 by machining such as cutting. As a result, the fixing force increases in the fixing region 4 between the substrate 1 and the housing 5, and a more reliable sensor device can be provided.

  Next, a fourth embodiment of the present invention will be described with reference to FIGS.

  A different configuration from the previous embodiment is that the groove 6 on the substrate 1 is formed only on one surface of the substrate 1. Even in this configuration, the variation in the thickness 20b between the grooves can be made smaller than the variation in the thickness 20a of the substrate 1, and it is needless to say that the same effects as the previous embodiments can be obtained. Furthermore, by forming the groove 6 only on one surface, the step of processing the groove can be reduced, so that a highly reliable sensor device can be provided while reducing the manufacturing cost.

  Next, a fifth embodiment of the present invention will be described with reference to FIGS.

  The difference from the previous embodiment is that a protective layer 8 is formed on the surface of the substrate 1 and a groove 6 is formed on the protective layer 8. Needless to say, this configuration also provides the same operational effects as the previous embodiments. Furthermore, by forming a protective layer on the surface of the substrate 1, it is possible to prevent corrosive gas and the like from entering the substrate 1, so that a more reliable sensor device can be provided.

  Further, as shown in FIGS. 26 to 28, it is needless to say that the same effect can be obtained by forming the protective film 8 on the groove 6 after forming the groove 6 on the surface of the substrate 1.

  Of course, the embodiments can be combined.

DESCRIPTION OF SYMBOLS 1 ... Board | substrate 2 ... Sensor element 3 ... Electronic component 4 ... Fixed area | region 5 ... Housing 6 ... Groove 7 ... Protruding part 8 ... Protective layer 10 ... Sensor assembly 12 ... Subway 13 ... Electronic component 14 ... Sensor element
DESCRIPTION OF SYMBOLS 15 ... Sensor element 16 ... Sensor element 20a ... Thickness of board | substrate 20b ... Thickness between grooves 25 ... Mold 26 ... Air

Claims (12)

A sub-passage that takes in a part of the fluid to be measured, a sensor element disposed in the sub-passage, a substrate on which the sensor element is mounted, and a housing that holds the substrate,
The housing has a fixing portion that holds the substrate while forming a part of the wall surface of the sub-passage, and the substrate has a groove formed in a direction along the fixing portion,
The groove portion is a sensor device in which a bottom portion thereof is formed so as to have a region where the substrate is held by the fixing portion and a region which is not in contact with the fixing portion.   The sensor device according to claim 1, wherein a bottom surface of the groove portion is a cutting surface.   The sensor device according to claim 1, wherein there are two groove portions, and a convex portion is formed along the fixed portion.   The sensor device according to claim 1, wherein the groove is formed on a surface of the substrate on which a sensor element is mounted.   The sensor device according to claim 1, wherein a protective film is formed on the surface of the groove.   The sensor device according to claim 1, wherein a protective film is formed on the surface of the substrate, and the groove is formed on the protective film.   The sensor device according to claim 1, wherein the sensor element is a flow rate sensor that measures a flow rate of gas flowing into the sub-passage.   The sensor device according to claim 7, wherein the substrate has a plurality of sensor elements.   The sensor device according to claim 1, wherein the substrate is a printed circuit board.   The sensor device according to claim 1, wherein the substrate is a ceramic substrate.   The sensor device according to claim 1, wherein the housing is formed of a thermoplastic resin. A sensor device, a substrate on which the sensor element is mounted, and a sensor device manufacturing method for fixing a housing for holding the substrate by molding,
Forming a groove in the substrate;
And a step of pressing a mold for forming a fixing portion into the groove, injecting resin, and forming the fixing portion.

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