JP2651967B2 - Semiconductor pressure sensor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor pressure sensor for detecting a pressure such as an intake air pressure, an atmospheric pressure, or an exhaust pressure of an internal combustion engine mounted on an automobile or the like.

[0002]

2. Description of the Related Art In recent years, with the tightening of exhaust gas regulations for automobiles, automobile engines have been required to be controlled so as to always be in the best combustion state regardless of their operating conditions.

[0003] Therefore, the intake pressure of the engine is detected by using a pressure sensor, and the detected pressure is converted into an electric signal to electronically control the fuel supply amount, and the ignition timing is controlled so as to maintain an optimal combustion state. Or a method of detecting a change in atmospheric pressure and performing advanced correction has been adopted.

[0004] Pressure sensors for automobiles used in such applications are required to have excellent heat resistance and earthquake resistance.
In response to this, semiconductor gauge type pressure sensors have been widely adopted.

A conventional semiconductor pressure sensor of this type will be described below with reference to FIGS. FIG. 3 is a partially broken plan view of a conventional semiconductor pressure sensor, and FIG.
FIG. 5 is a sectional view taken along line KK of FIG. 3, and FIG. 6 is a partially broken side view showing a state in which a conventional semiconductor pressure sensor is mounted on a circuit board such as an engine controller.

3 and 4, reference numeral 31 denotes a pressure-sensitive diaphragm; 32, a sensor element having a pressure-sensitive diaphragm 31; 33, a pedestal joined to the sensor element 32 by means such as electrostatic joining; The spacer, 35 is a hybrid circuit board, and 36 is an electronic component such as a capacitor mounted on the hybrid circuit board 35. Along with these electronic components 36 and the like, the hybrid circuit board 35 is provided with a temperature compensation circuit, an amplification circuit, a filtering circuit, and the like. The metal spacer 34 and the hybrid circuit board 35 are joined by soldering or by means such as an adhesive. Reference numeral 37 denotes a bonding wire for connecting an electrode (not shown) formed on the sensor element 32 to the hybrid circuit board 35, and reference numeral 38 denotes a gel potted so as to cover the sensor element 32 and the bonding wire 37. Reference numeral 39 denotes a case which is bonded and fixed on the hybrid circuit board 35 so as to cover the sensor element 32 and the bonding wires 37, and reference numeral 40 denotes a case 3
9 is a cap adhesively fixed to the open upper surface,
Reference numeral 1 denotes a pressure intake hole 41 formed in the cap 40.
It is.

[0007] In FIG. 3, reference numeral 42 denotes a circuit board mounted on the hybrid circuit board 35.
And a plurality of lead terminals for outputting a signal from the terminal.
43 is a hybrid circuit board 3 of these lead terminals 42
A clip portion formed on the base portion on the fifth side for electrically connecting each lead terminal 42 to the hybrid circuit board 35. Reference numeral 44 denotes a V-cut portion formed at the end of each lead terminal 42 so as to be easily inserted into an insertion hole of a circuit board such as an engine controller described later. Reference numeral 45 denotes a socket mounted on each lead terminal 42. Of the plurality of lead terminals 42, the f terminal is a ground (GND), the g terminal is a power input terminal, the h terminal is a sensor output terminal, and the remaining terminals a to e and i to l are for characteristic check. And a terminal that is inserted into a circuit board such as an engine controller and serves to hold the semiconductor pressure sensor.

As shown in FIG. 5, the side surface of the socket 45 has a substantially convex shape, and the upper surface 46 of the socket 45 has the clip portion of the lead terminal 42 with the socket 45 mounted on the hybrid circuit board 35. A taper groove 47 into which a part of 43 is immersed is formed. A lead terminal 42 extends from the deepest portion of the taper groove 47 to the bottom surface 48 of the socket 45.
An insertion hole 49 for inserting the V cut portion 44 is formed. Reference numeral 50 denotes a clip portion formed integrally with the socket 45 to hold the hybrid circuit board 35. Reference numeral 51 denotes a coating agent for moisture resistance insulation applied so as to cover a plane portion of the hybrid circuit board 35 to which the sensor element 32 and the like are joined.

In FIG. 6, reference numeral 60 denotes a circuit board on which the semiconductor pressure sensor is mounted, for example, an engine controller, for inserting a plurality of V-cut portions 44 of the lead terminals 42 exposed from the bottom surface 48 of the socket 45. An insertion hole 61 is formed. Reference numeral 62 denotes solder for joining the circuit board 60 and the V-cut portion 44 of the lead terminal 42.

Next, the order of assembling the conventional semiconductor pressure sensor constructed as described above will be described. As shown in FIG. 5, the V cut portion 44 of the lead terminal 42 is
When the socket 45 is mounted on the hybrid circuit board 35 by inserting the socket 45 into the insertion hole 49 from the tapered groove 47 of the fifth connector 5, the clip portion 43 of the lead terminal 42
7. In this state, the lead terminal 4
The second V-cut portion 44 is exposed from the bottom surface 48 of the socket 45. As shown in FIG.
When the semiconductor pressure sensor is inserted into the insertion hole 61 of the circuit board 60 such as an engine controller, the bottom surface 48 of the socket 45 comes into contact with the board surface of the circuit board 60, and the semiconductor pressure sensor is mounted on the circuit board 60.
It will be placed in a stable state on top. Next, the V-cut portion 44 of the lead terminal 42 inserted into the insertion hole 61 is bonded and fixed on the back side of the circuit board 60 with solder 62, and the mounting of the semiconductor pressure sensor on the circuit board 60 is completed.

[0011]

However, in the above conventional configuration, the sensor element 32 and the bonding wire 3
7, the cap 40 is bonded to the case 39 mounted on the hybrid circuit board 35 with an adhesive so that the adhesive when the cap 40 is bonded to the case 39 flows into the case 39. As a result, there is a problem that the sensor element 32 and the gel 38 coated on the bonding wire 37 may adhere to and mix with each other, thereby lowering the sensitivity or reliability of the sensor element 32.

The present invention is intended to solve such a conventional problem, and eliminates the influence of a cap adhesive on a pressure-sensitive portion, thereby improving the reliability of an automotive electrical component. It is an object to provide a pressure sensor.

[0013]

According to the present invention, there is provided a semiconductor pressure sensor having a case and a cap bonded and fixed to a hybrid circuit board to protect a sensor element and a bonding wire. A relief groove is formed on the upper surface of the case to prevent the adhesive fixing the case and the cap from flowing into the case, and a ventilation groove for communicating the relief groove with the inside of the case is formed. Is formed on the lower surface.

[0014]

According to the present invention, the escape groove formed on the upper surface of the case prevents the adhesive from flowing into the inside of the case, so that the leaked adhesive adheres to and mixes with the gel coated on the pressure-sensitive portion. Without lowering the sensitivity and reliability of the pressure-sensitive portion. Also, since the escape groove and the inside of the case are communicated by the ventilation groove formed on the lower surface of the cap, no air is sealed in the escape groove, and the semiconductor pressure sensor is mounted on a circuit board such as an engine controller. Therefore, even when the sensor is mounted in a high temperature place such as in an engine room, it is possible to avoid a situation in which the enclosed air is expanded due to a rise in the temperature in the engine room, and to reduce the sensitivity and reliability of the pressure sensing part. Can be prevented.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIGS. 1A is a cross-sectional view of the semiconductor pressure sensor according to one embodiment of the present invention, taken along line II of FIG. 2, FIG. 1B is a partially enlarged view of FIG. 1A, and FIG. FIG. 2 is a partially broken plan view of the semiconductor pressure sensor shown in FIG. 1.

1 and 2, reference numeral 1 denotes a pressure-sensitive diaphragm, 2 denotes a sensor element having a pressure-sensitive diaphragm 1,
3 is a pedestal joined to the sensor element 2 by means such as electrostatic joining, 4 is a metal spacer, 5 is a hybrid circuit board,
Reference numeral 6 denotes an electronic component such as a capacitor mounted on the hybrid circuit board 5. Along with these electronic components 6 and the like, the hybrid circuit board 5 includes a temperature compensation circuit, an amplification circuit, a filtering circuit, and the like. The metal spacer 4 and the hybrid circuit board 5 are joined by an adhesive. Reference numeral 7 denotes a bonding wire for connecting an electrode (not shown) formed on the sensor element 2 to the hybrid circuit board 5, and reference numeral 8 denotes a gel coated so as to cover the surfaces of the sensor element 2 and the bonding wire 7. Reference numeral 9 denotes a case that is bonded and fixed on the hybrid circuit board 5 so as to surround the sensor element 2 and the bonding wires 7. Reference numeral 10 denotes a cap that is bonded and fixed to the open upper surface of the case 9. Hole 1
1 is provided.

In FIG. 2, reference numeral 12 denotes a plurality of lead terminals which are mounted on the hybrid circuit board 5 and output signals from the hybrid circuit board 5;
Are clip portions formed at the bases of these lead terminals 12 on the side of the hybrid circuit board 5 for attaching each lead terminal 12 to the hybrid circuit board 5. Reference numeral 14 denotes a V-cut portion formed at the end of each lead terminal 12 so as to be easily inserted into an insertion hole of a circuit board such as an engine controller described later. Reference numeral 15 denotes a socket to be mounted on these lead terminals 12. These plural lead terminals 1
Of the two terminals, the f terminal is for ground (GND), the g terminal is a power input terminal, the h terminal is a sensor output terminal, and the remaining terminals a to e and i to l are characteristic check terminals and an engine controller. And the like, which are inserted into a circuit board and serve to hold the semiconductor pressure sensor.

The socket 15 has a substantially convex side surface, and a part of the clip portion 13 of the lead terminal 12 is recessed into the upper surface 16 of the socket 15 with the socket 15 mounted on the hybrid circuit board 5. A tapered groove 17 is formed, and an insertion hole 19 for inserting the V cut portion 14 of the lead terminal 12 is formed from the deepest portion of the tapered groove 17 to the bottom surface 18 of the socket 15. Reference numeral 20 denotes a clip portion formed integrally with the socket 15 to hold the hybrid circuit board 5. Reference numeral 21 denotes a moisture-resistant insulating coating applied to cover the flat portion of the hybrid circuit board 5 to which the sensor element 2 and the like are joined.

A cap 10 is provided on the upper surface of the case 9.
An escape groove 22 is formed in an annular shape to prevent an adhesive for bonding and fixing the resin from flowing into the case 9. On the lower surface of the cap 10, a ventilation groove 23 is formed in an annular shape to communicate the escape groove 22 with the inside of the case 9. The ventilation groove 23 is provided between the case 9 and the cap 10.
To prevent air from being trapped in the escape groove 22 at the time of thermosetting of the adhesive for fixing the
This is because, when air is sealed in the inside, the sealed air expands when the temperature rises, thereby lowering the sensitivity and reliability of the pressure-sensitive portion.

Next, the operation of the semiconductor pressure sensor of the present embodiment configured as described above will be described. A signal from the hybrid circuit board 5 on which the sensor element 2 is mounted is output to a circuit board such as an engine controller to which the socket 15 is connected through a socket 15 mounted on the lead terminal 12. When this engine controller is placed in a place where the temperature becomes high, such as in an engine room, the temperature rise causes the thermal expansion of the hybrid circuit board 5 and the socket 15. Is held by the clip portion 13 of the socket 15 and the clip portion 20 of the socket 15, the thermal expansion therebetween is absorbed, and the thermal stress concentrates on the solder joint which joins the lead terminal 12 and a circuit board such as an engine controller. Can be prevented, the deterioration of the solder joint due to thermal stress can be prevented, and the reliability as automotive electrical components can be improved.

Further, a relief groove 22 is provided on the upper surface of the case 9 to prevent the adhesive for fixing the case 9 and the cap 10 from flowing into the case 9. It is possible to prevent the adhesive from adhering and mixing into the coated gel 8 to lower the sensitivity and reliability of the pressure-sensitive portion. Further, since the ventilation groove 23 is provided on the lower surface of the cap 10 to prevent air from being enclosed in the escape groove 22, it is possible to avoid a situation in which the enclosed air is thermally expanded due to a temperature rise in the engine room or the like. In addition, it is possible to prevent the sensitivity and the reliability of the pressure-sensitive part from lowering.

[0022]

As described above, according to the present invention, the escape groove formed on the upper surface of the case prevents the adhesive from flowing out into the case, so that the released adhesive is coated on the pressure-sensitive portion. The sensitivity and reliability of the pressure-sensitive part can be prevented from lowering without adhering to the gel.
Also, since the escape groove and the inside of the case are communicated by the ventilation groove formed on the lower surface of the cap, no air is sealed in the escape groove, and the semiconductor pressure sensor is mounted on a circuit board such as an engine controller. Therefore, even when the sensor is mounted in a high temperature place such as in an engine room, it is possible to avoid a situation in which the enclosed air is expanded due to a rise in the temperature in the engine room, and to reduce the sensitivity and reliability of the pressure sensing part. Can be prevented.

[Brief description of the drawings]

1A is a cross-sectional view of a semiconductor pressure sensor according to an embodiment of the present invention, taken along line II of FIG. 2; FIG. 1B is a partially enlarged view of FIG.

FIG. 2 is a partially broken plan view of the semiconductor pressure sensor shown in FIG.

FIG. 3 is a partially broken plan view of a conventional semiconductor pressure sensor.

FIG. 4 is a sectional view taken along the line JJ of FIG. 3;

FIG. 5 is a sectional view taken along the line KK in FIG. 3;

FIG. 6 is a partially broken side view showing a state where a conventional semiconductor pressure sensor is mounted on a circuit board such as an engine controller.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Pressure sensitive diaphragm 2 Sensor element 5 Hybrid circuit board 7 Bonding wire 8 Gel 9 Case 10 Cap 11 Pressure intake hole 22 Escape groove 23 Vent groove

 ──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-3-76131 (JP, A) JP-A-3-71030 (JP, A) JP-A-61-56543 (JP, U)

Claims (1)

(57) [Claims] A sensor element having a pressure-sensitive diaphragm; a bonding wire connecting the sensor element to a hybrid circuit board; a gel coated so as to cover surfaces of the sensor element and the bonding wire; A case that is adhesively fixed to the hybrid circuit board so as to surround a periphery of the sensor element and the bonding wire; and a cap that has a hole for pressure intake and is adhesively fixed to an upper surface of the case, further comprising the case. And a relief groove formed on the upper surface of the case to prevent the adhesive for fixing the cap from flowing into the case,
A semiconductor pressure sensor comprising: a ventilation groove formed on a lower surface of the cap for communicating the escape groove with the inside of the case.