JP4090395B2 - Pressure detection device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a pressure detection equipment, in particular, suitable for those having a structure of mounting the the lead member integrally molded outer case, the electronic component to reduce the electronic circuitry and electric disturbance having an output signal The present invention relates to a pressure detection device.
[0002]
[Prior art]
For example, as disclosed in JP-A-10-170380, a conventional pressure detection device includes a semiconductor sensor chip that converts a physical quantity into an electric signal, and a semiconductor circuit that obtains a detection signal by performing arithmetic processing on the sensor output signal. This is a sensor device having a two-chip configuration including chips. In this two-chip configuration, the semiconductor circuit chip is disposed on the lead frame and then sealed with resin, and a package having a recessed cavity in part is formed, and the semiconductor sensor chip is disposed in the recessed cavity to electrically The sensor unit joined to the outer casing is disposed in the concave opening of the outer case integrally formed with the lead member having a concave opening and part of which is a connector terminal and part of which is exposed to the concave opening. After the lead frame was electrically joined, it was closed with a cover.
[0003]
[Patent Document 1]
Japanese Patent Laid-Open No. 10-170380
[Problems to be solved by the invention]
However, in the conventional two-chip sensor device, when the specifications required by the user for transient voltage resistance and electromagnetic resistance are more severe, there are cases where the specifications cannot be satisfied with the conventional semiconductor chip. At this time, it is necessary to redesign the customized chip to cope with it, and there is a problem that a lot of development man-hours and costs are generated.
[0005]
Accordingly, the present inventors have disclosed, as Japanese Patent Application No. 2001-351539, a lead member, an exterior case integrally formed with the lead member and provided with an opening in a part thereof, and a semiconductor sensor that converts pressure into an electrical signal. And a signal processing circuit, an output terminal for outputting the processed signal, a sensor unit whose main component is a chip case provided with a part of an opening, and an electronic component for reducing electrical disturbance, The sensor unit and the electronic component are disposed in the opening of the outer case, and the lead member, the electronic component, and the terminal of the sensor unit are electrically connected in the opening of the outer case. Propose what you did.
[0006]
As a result of further investigation on the proposed configuration, the thermal stress repeatedly generated from the exterior case having a large linear expansion coefficient may cause cracks in the solder for fixing the electronic component to the lead member, resulting in disconnection. It has been found.
[0007]
An object of the present invention is to provide a pressure detection device with improved reliability by reducing thermal stress generated from an exterior case material and preventing a crack from occurring in a connection part of a mounted electronic component.
[0008]
[Means for Solving the Problems]
(1) In order to achieve the above object, the present invention provides a plurality of lead members, one end of which serves as an electrical connection connector terminal, and an exterior case integrally formed by holding the lead members by resin molding. And an electronic circuit unit that is disposed in the opening of the outer case and electrically connected to the lead member, and an electronic component that is fixed and electrically connected between the plurality of lead members. The lead member is fixed to the outer case in the vicinity of both ends thereof to be in a restrained state, and a convex portion is provided on an opening surface formed inside the outer case, and the lead member is provided on the upper surface of the convex portion. By disposing the electronic component, the electronic component is fixed to the lead member at a non-restraining portion between the restraining portions of the lead member.
With such a configuration, it is possible to improve the reliability by reducing the thermal stress generated from the exterior case material and preventing the occurrence of cracks in the connection part of the mounted electronic component.
[0012]
( 2 ) In the above (1), preferably, the electronic component connected on the lead member is hardened and sealed with a resin having a linear expansion coefficient smaller than that of the outer case and larger than that of the electronic component.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
The configuration of the electronic device according to the first embodiment of the present invention will be described below with reference to FIGS. In the present embodiment, a case where the electronic device is applied to a pressure detection device will be described as an example.
FIG. 1 is a cross-sectional view showing a configuration of a pressure detection device which is an electronic device according to a first embodiment of the present invention. FIG. 1 shows a BB cross section of FIG. FIG. 2 is a plan view of FIG. 1 and shows a state where the sealing resin of FIG. 1 is removed. 3 is a cross-sectional view taken along the line AA in FIG. In each figure, the same numerals indicate the same parts.
[0014]
As shown in FIG. 1, the detection unit terminal 3 is integrally formed with the detection unit case 4. The detection unit 1 is bonded and fixed to the detection unit case 4. The detection unit 1 is configured by forming a diaphragm and a circuit on silicon, and anodic bonding with a glass pedestal.
[0015]
The detection unit case 4 is made of epoxy resin or polyphenylin sulfide (PPS) resin. The detection unit terminal 3 is formed by integrally molding phosphor bronze plated with nickel. The detection unit terminal 3 and the detection unit 1 are connected by a connection wire 2 made of aluminum or gold, and are electrically connected. The detection unit 1, the detection unit terminal 3, and the detection unit case 4 constitute a sensor unit, that is, an electronic circuit unit.
[0016]
The outer case 5 is made of a resin material such as polybutyl terephthalate (PBT) or polyphenylin sulfide (PPS). A metal lead member 9b is fixed to the outer case 5 by integral molding. As shown in FIG. 2, the lead member 9 is composed of three lead members 9a, 9b, 9c.
[0017]
A connector 5a is formed at the right end of the outer case 5 so as to output a signal to the outside. One end (the end on the right side in the figure) of the lead member 9b is a connector terminal 9x3. In the example shown in FIG. 2, for example, the lead member 9a is used as a ground terminal, the lead member 9b is used as a signal detection terminal, and the lead member 9c is used as a power supply terminal.
[0018]
The other end portion 9x1 of the lead member 9b and a portion 9x2 adjacent to the one end portion 9x3 are embedded in the outer case 5 at the time of molding and are fixed. That is, the lead member 9b is constrained by the outer case 5 at both ends or in the vicinity thereof. Similarly, the other lead members 9a and 9c are restrained by the outer case 5 at two places. Other than the two places are in an unconstrained state. At the position between the two restraining positions 9x1 and 9x2, the electronic components 7 and 8 are electrically connected by a connecting member made of solder or conductive paste so as to straddle between the lead members 9. The electronic components 7 and 8 are, for example, chip capacitors. As shown in FIG. 2, the chip capacitor 7 is connected between the lead member 9a and the lead member 9c. The chip capacitor 8 is connected between the lead member 9a and the lead member 9b. That is, the chip capacitors 7 and 8 that are electronic components are fixed to the unconstrained position of the lead member 9.
[0019]
The upper part of the exterior case 5 is opened to mount the electronic circuit unit including the detection unit case 4 and the electronic components 7 and 8. The detection unit case 4 is mounted in the opening of the outer case 5, the detection unit terminal 3 and the lead member 9 are connected by welding, and a sealing material 10 made of epoxy resin is further formed in the opening of the outer case 5. The pressure detection device is completed by injecting and curing without gaps. The sealing material 10 uses a thermosetting resin such as an epoxy resin.
[0020]
A cylindrical pipe 5 c is formed on the lower right side of the outer case 5. An external pressure (atmospheric pressure or intake pressure) is introduced from the pipe 5 c, and this pressure is detected by the detection unit 1.
[0021]
Next, the cross-sectional shape of the electronic component mounting position will be described with reference to FIG.
[0022]
As shown in the drawing, the height of the opening surface 6 of the outer case 5 is made lower than the bottom surfaces of the lead members 9a, 9b, 9c. For this purpose, three convex portions 5d1, 5d2, and 5d3 are formed on the bottom surface of the opening on the upper surface side of the outer case 5, and are formed in the shape of comb teeth. The lead members 9a, 9b, and 9c are set inside the mold and resin-molded to form the outer case 5, thereby fixing the lead member 9 to the outer case 5. In this case, FIG. At the cross-sectional position shown, the bottom surfaces of the lead members 9a, 9b, 9c and the top surfaces of the convex portions 5d1, 5d2, 5d3, that is, the surfaces where both are in contact, are not fixed and are in a free state, that is, unconstrained. It is in a state. After the outer case 5 is molded, the electronic component 8 is electrically connected by the connecting member 11 made of solder or conductive paste across the lead members 9a and 9b.
[0023]
When the lead member 9 is configured as has been or come buried in the opening surface of the case 5, in the position of a section of FIG. 3, the lead member is in a state of being restrained. The linear expansion coefficient of the chip capacitor, which is the electronic component 8 fixed on the lead member 9 with solder or the like, is, for example, 10 ppm / ° C., whereas the wire of the resin material such as PBT or PPS of the outer case 5 The expansion coefficient is, for example, 40 ppm / ° C. Therefore, with such a configuration, it has been found that the thermal stress repeatedly generated from the exterior case having a large linear expansion coefficient may cause a crack in the solder for fixing the electronic component to the lead member, resulting in disconnection.
[0024]
On the other hand, in the present embodiment, the lead member 9 is in an unconstrained state at the position where the electronic component 8 is mounted by restraining the two ends of the lead member 9 or in the vicinity thereof. Even if this occurs repeatedly, cracks are less likely to occur in the solder for fixing the electronic component to the lead member.
[0025]
Further, after fixing the electronic component 8 on the lead members 9a and 9b with the connecting member 11, the sealing material 10 made of epoxy resin is injected into the opening on the upper surface of the outer case 5 without any gap, and is thermally cured. Yes. Here, in order to make the linear expansion coefficient of the sealing material 10 smaller than that of the outer case 11 and larger than that of the electronic components 7 and 8, an epoxy resin having a linear expansion coefficient of 20 to 30 ppm / ° C. is used. As described above, the relationship between the linear expansion coefficients of the constituent materials is as follows: exterior case 5> sealing material 10> electronic parts 7 and 8, so that the heat displacement of the exterior case 5 having the largest linear expansion coefficient is sealed. Since the structure is constrained by the stopper 10, the thermal stress in the connection member 11 can be reduced, and the progress of cracks generated in the connection member 11 can be reduced.
[0026]
As described above, according to the present embodiment, the thermal stress generated from the exterior case material is reduced, and cracks are less likely to occur at the connection portion of the mounted electronic component, thereby improving the reliability.
[0027]
Next, the configuration of the electronic device according to the second embodiment of the present invention will be described with reference to FIG. The overall configuration of the pressure detection device that is the electronic device according to the present embodiment is the same as that shown in FIGS. 1 and 2.
FIG. 4 is a diagram showing a cross-sectional configuration of an electronic device according to the second embodiment of the present invention, and is a cross-sectional view taken along the line AA of FIG. In addition, the same code | symbol as FIG. 3 has shown the same part.
[0028]
In the present embodiment, the opening surface 6a of the outer case 5 is flat and the height thereof is the same as the bottom surfaces of the lead members 9a, 9b, 9c. The side surface of the lead member 9 is constrained by the sealing material 10.
[0029]
In addition, when molding the metal lead member 9 in the outer case 5, the mold resin is placed on the side surface of the lead member 9 and in a portion (a portion indicated by an arrow y 1) in contact with the opening surface of the outer case 5. In some cases, the lead member 9 may wrap around to the side surface, but the amount thereof is considerably small, and the lead member 9 can be substantially unrestrained.
[0030]
Further, after fixing the electronic component 8 on the lead members 9a and 9b with the connecting member 11, the sealing material 10 made of epoxy resin is injected into the opening on the upper surface of the outer case 5 without any gap, and is thermally cured. Yes.
[0031]
As described above, according to the present embodiment, since the electronic component is mounted on the unconstrained place of the lead member and the displacement due to the heat of the exterior case 5 is constrained by the sealing material 10, the exterior case Even if thermal stress is repeatedly generated, cracks are less likely to occur in the solder for fixing the electronic component to the lead member, and the reliability is improved.
[0032]
Next, the configuration of the electronic device according to the third embodiment of the present invention will be described with reference to FIG. The overall configuration of the pressure detection device that is the electronic device according to the present embodiment is the same as that shown in FIGS. 1 and 2.
FIG. 5 is a diagram showing a cross-sectional configuration of an electronic device according to the third embodiment of the present invention, and is a cross-sectional view taken along the line AA of FIG. In addition, the same code | symbol as FIG. 3 has shown the same part.
[0033]
In the present embodiment, with respect to the configuration shown in FIG. 3, the corner where the opening surface 6 b of the exterior case 5 and the side surface of the lead member 9 intersect is rounded. That is, the bottom surface of the groove adjacent to the protrusions 5d1 ′, 5d2 ′, and 5d3 ′ is rounded to form a groove having a U-shaped cross section. The side surface of the lead member 9 is constrained by the sealing material 10. As a result, when there is a corner portion in the groove portion between the convex portions, the stress concentrated on the corner portion is dispersed, and the generation of cracks can be more effectively prevented.
[0034]
Further, after fixing the electronic component 8 on the lead members 9a and 9b with the connecting member 11, the sealing material 10 made of epoxy resin is injected into the opening on the upper surface of the outer case 5 without any gap, and is thermally cured. Yes.
[0035]
As described above, according to the present embodiment, the thermal stress generated from the exterior case material is reduced, and cracks are less likely to occur at the connection portion of the mounted electronic component, thereby improving the reliability.
[0036]
Next, the configuration of the electronic device according to the fourth embodiment of the present invention will be described with reference to FIG. The overall configuration of the pressure detection device that is the electronic device according to the present embodiment is the same as that shown in FIGS. 1 and 2.
FIG. 6 is a cross-sectional view of the electronic device according to the fourth embodiment of the present invention, and is a cross-sectional view taken along the line AA of FIG. In addition, the same code | symbol as FIG. 3 has shown the same part.
[0037]
In the present embodiment, similarly to the configuration shown in FIG. 5, the corner where the opening surface 6 c of the outer case 5 intersects with the side surface of the lead member 9 is chamfered. That is, the groove portion adjacent to the convex portions 5d1 ″, 5d2 ″, 5d3 ″ is chamfered from the bottom surface to the side surface. The side surface of the lead member 9 is constrained by the sealing material 10. When there is a corner in the groove between the convex portions, the stress concentrated on the corner is dispersed, and the generation of cracks can be more effectively prevented.
[0038]
Further, after fixing the electronic component 8 on the lead members 9a and 9b with the connecting member 11, the sealing material 10 made of epoxy resin is injected into the opening on the upper surface of the outer case 5 without any gap, and is thermally cured. Yes.
[0039]
As described above, according to the present embodiment, the thermal stress generated from the exterior case material is reduced, and cracks are less likely to occur at the connection portion of the mounted electronic component, thereby improving the reliability.
[0040]
【The invention's effect】
According to the present invention, the thermal stress generated from the exterior case material is reduced, so that cracks are not generated in the connection portion of the mounted electronic component, and the reliability is improved.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a configuration of a pressure detection device which is an electronic device according to a first embodiment of the present invention.
2 is a plan view of FIG. 1. FIG.
3 is a cross-sectional view taken along the line AA in FIG.
FIG. 4 is a diagram showing a cross-sectional configuration of an electronic device according to a second embodiment of the present invention.
FIG. 5 is a diagram showing a cross-sectional configuration of an electronic device according to a third embodiment of the present invention.
FIG. 6 is a diagram showing a cross-sectional configuration of an electronic device according to a fourth embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Detection part 2 ... Connection wire 3 ... Detection part terminal 4 ... Detection part case 5 ... Outer case 6 ... Opening surface 7, 8 ... Electronic component 9 ... Lead member 10 ... Sealing material 11 ... Connection member

Claims (2)

A plurality of lead members whose one end is a connector terminal for electrical connection;
An exterior case that is integrally molded by holding the lead member by resin molding,
An electronic circuit unit that is disposed in the opening of the outer case and is electrically connected to the lead member;
An electronic component that is fixed and electrically connected between the plurality of lead members,
The lead member is fixed to the outer case near its both ends and is in a restrained state,
By providing a convex part on the opening surface formed inside the exterior case and arranging the lead member on the upper surface of the convex part, the electronic component is in a non-constrained part between the constraining parts of the lead member, A pressure detection device fixed to the lead member. The pressure detection device according to claim 1,
An electronic component connected on the lead member is cured and sealed with a resin having a linear expansion coefficient smaller than that of the outer case and larger than that of the electronic component.

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