JPH05164647A - Semiconductor pressure sensor - Google Patents

Abstract

PURPOSE:To prevent reduction in sensitivity and reliability of a sensor due to thermal pressure caused by poor influence due to flow-in of an adhesive and temperature increase at a packaging location. CONSTITUTION:A title item is provided with a sensor element 2 with a pressure- sensitive diaphragm 1, a bonding wire 7 which connects the sensor element and a hybrid circuit substrate 5, a gel 8 which is applied surface of the sensor element 2 and the bonding wire 7, a case 9 which is adhered and fixed to the hybrid circuit substrate 5 so that it surrounds a perimeter of the sensor element 2 and the bonding wire 7, and a cap 10 with a hole 11 for taking in pressure and is adhered and fixed to an upper surface of the case 9. An escape groove 22 for preventing flow-out into the case 9 of the adhesive fixing the case and the cap 10 is provided on an upper surface of the case 9 and a breathing groove 23 for communicating the escape groove 22 and an inside of the case 9 is provided on a lower surface, thus preventing air from being sealed the escape groove 22.

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 pressure such as intake air pressure, atmospheric pressure or exhaust pressure of an internal combustion engine mounted on an automobile or the like.

[0002]

2. Description of the Related Art In recent years, as automobile exhaust gas regulations have been tightened, it has been required that an automobile engine be always controlled to be in the best combustion state regardless of its operating state.

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

Pressure sensors for automobiles used for such purposes are required to have excellent heat resistance and earthquake resistance.
Semiconductor gauge type pressure sensors have come to be widely adopted as a means for responding to this.

A conventional semiconductor pressure sensor of this type will be described below with reference to FIGS. 3 to 6. FIG. 3 is a partially cutaway plan view of a conventional semiconductor pressure sensor, and FIG. 4 is J of FIG.
FIG. 5 is a sectional view taken along line -J, FIG. 5 is a sectional view taken along line KK in FIG. 3, and FIG. 6 is a partially cutaway side view showing a state in which a conventional semiconductor pressure sensor is mounted on a circuit board such as an engine controller.

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

Further, in FIG. 3, 42 is mounted on the hybrid circuit board 35.
Is a plurality of lead terminals for outputting signals from.
43 is the hybrid circuit board 3 of these lead terminals 42
A clip portion formed on the base portion on the fifth side for electrically connecting the lead terminals 42 to the hybrid circuit board 35. Reference numeral 44 denotes a V-cut portion formed at the tip 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 is a socket attached to each lead terminal 42. Of the plurality of lead terminals 42, the f terminal is for grounding (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 checked. It is a terminal which is inserted into a circuit board such as a power supply terminal and an engine controller and which serves to hold the semiconductor pressure sensor.

As shown in FIG. 5, the socket 45 has a substantially convex side surface, 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 in which a part of 43 is recessed is formed. From the deepest portion of the taper groove 47 to the bottom surface 48 of the socket 45, the lead terminal 42 is formed.
An insertion hole 49 for inserting the V cut portion 44 is formed. Reference numeral 50 denotes a clip portion integrally formed with the socket 45 for holding the hybrid circuit board 35. Reference numeral 51 is a coating agent for moisture-proof insulation that is applied so as to cover the flat surface 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, such as an engine controller, on which the semiconductor pressure sensor is mounted. The circuit board 60 has 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. Further, 62 is a 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 connected to the socket 3
When the socket 45 is inserted into the insertion hole 49 from the taper groove 47 of No. 5 and the socket 45 is attached to the hybrid circuit board 35, the clip portion 43 of the lead terminal 42 is made into the taper groove 4 of the socket 45.
It is in a state of abutting on 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, and the V-cut portion 43 is formed as shown in FIG.
When it 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 contacts the board surface of the circuit board 60, and the semiconductor pressure sensor moves the circuit board 60.
It will be placed on top in a stable condition. Next, the V-cut portion 44 of the lead terminal 42 inserted into the insertion hole 61 is joined and fixed with solder 62 on the back surface side of the circuit board 60, and the mounting of the semiconductor pressure sensor on the circuit board 60 is completed.

[0011]

However, in the above-mentioned conventional configuration, the sensor element 32 and the bonding wire 3 are used.
Since the cap 40 is bonded to the case 39 mounted on the hybrid circuit board 35 so as to surround the case 7 with the adhesive, the adhesive when the cap 40 is bonded to the case 39 flows out into the case 39. Then, there is a problem in that the sensor element 32 and the bonding wire 37 may adhere to and mix with the gel 38, which reduces the sensitivity or reliability of the sensor element 32.

The present invention is intended to solve such a conventional problem, and it is possible to eliminate the influence of the cap adhesive on the pressure-sensitive portion and to improve the reliability as an automobile electrical component application. An object is to provide a pressure sensor.

[0013]

In order to achieve the above object, the present invention is a semiconductor pressure sensor having a case and a cap that are adhesively fixed to a hybrid circuit board to protect the sensor element and the bonding wire. A clearance groove is formed on the upper surface of the case to prevent the adhesive that secures the case and the cap from flowing out into the case, and the ventilation groove for communicating the clearance groove and the inside of the case is formed with the cap. Is formed on the lower surface of the.

[0014]

Therefore, 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. Therefore, the outflowing adhesive adheres to and mixes with the gel coated on the pressure sensitive portion. It is possible to prevent deterioration of the sensitivity and reliability of the pressure sensitive portion. Further, since the escape groove and the inside of the case are communicated with each other by the ventilation groove formed on the lower surface of the cap, air is not enclosed in the escape groove, and the semiconductor pressure sensor is mounted on the circuit board such as the engine controller. Even if it is installed in a place where the temperature becomes high, such as in the engine room, it is possible to avoid the situation where the enclosed air expands as the temperature in the engine room rises, and the sensitivity and reliability of the pressure-sensitive part are reduced. Can be prevented.

[0015]

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

In FIGS. 1 and 2, reference numeral 1 is a pressure sensitive diaphragm, 2 is a sensor element having the pressure sensitive diaphragm 1,
3 is a pedestal joined to the sensor element 2 by means of electrostatic joining or the like, 4 is a metal spacer, 5 is a hybrid circuit board,
Reference numeral 6 is an electronic component such as a capacitor mounted on the hybrid circuit board 5. Along with these electronic components 6 and the like, a temperature compensating circuit, an amplifying circuit, a filtering circuit and the like are formed on the hybrid circuit board 5. The metal spacer 4 and the hybrid circuit board 5 are joined by an adhesive. Reference numeral 7 is a bonding wire that connects an electrode (not shown) formed on the sensor element 2 to the hybrid circuit board 5, and 8 is 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 adhesively fixed on the hybrid circuit board 5 so as to surround the sensor element 2 and the bonding wire 7, and 10 is a cap that is adhesively fixed to the open upper surface of the case 9 for pressure intake. Hole 1
1 is provided.

Further, in FIG. 2, reference numeral 12 is a plurality of lead terminals mounted on the hybrid circuit board 5 for outputting signals from the hybrid circuit board 5, and 13
Is a clip portion formed on the base portion of the lead terminals 12 on the hybrid circuit board 5 side for mounting each lead terminal 12 on the hybrid circuit board 5. Reference numeral 14 denotes a V-cut portion formed at the tip 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 is a socket attached to these lead terminals 12. These plural lead terminals 1
Of the two, the f terminal is for grounding (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 a characteristic checking terminal and an engine controller. Etc. is a terminal which is inserted into a circuit board such as to hold the present 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. A clip portion 20 is integrally formed with the socket 15 and holds the hybrid circuit board 5. Reference numeral 21 is a coating agent for moisture-proof insulation that is applied so as to cover the flat surface portion of the hybrid circuit board 5 to which the sensor element 2 and the like are joined.

Further, the cap 10 is provided on the upper surface of the case 9.
An escape groove 22 is formed in an annular shape to prevent the adhesive for fixing the adhesive from flowing out into the case 9. Further, on the lower surface of the cap 10, a ventilation groove 23 that connects the escape groove 22 and the inside of the case 9 is formed in an annular shape. The ventilation groove 23 is formed by the case 9 and the cap 10.
This is for preventing air from being enclosed in the escape groove 22 when the adhesive for fixing the adhesive is thermally cured.
This is because if air is enclosed in the inside, the enclosed air expands when the temperature rises, and the sensitivity and reliability of the pressure sensitive portion are reduced.

Next, the operation of the semiconductor pressure sensor of the present embodiment constructed as described above will be explained. 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 the socket 15 mounted on the lead terminal 12. When this engine controller is arranged in a place where the temperature becomes high, such as in the engine room, thermal expansion occurs in the hybrid circuit board 5 and the socket 15 as the temperature rises. Since it is held by the clip portion 13 of the socket and the clip portion 20 of the socket 15, the thermal expansion between them is absorbed, and the thermal stress is concentrated on the solder joint portion joining the lead terminal 12 and the circuit board such as the engine controller. Can be prevented, deterioration of the solder joint portion due to thermal stress can be prevented, and reliability for automotive electrical equipment applications can be improved.

Further, since the escape 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 out into the case 9, the sensor element 2 and the bonding wire 7 are prevented. It is possible to prevent the adhesive from adhering to and mixing with 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 the air from being enclosed in the escape groove 22, it is possible to avoid the situation where the enclosed air thermally expands due to the temperature rise in the engine room or the like. It is possible to prevent the sensitivity and reliability of the pressure sensitive portion from being lowered.

[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 into the case, so that the pressure sensitive portion is coated with the adhesive that has flowed out. It is possible to prevent the sensitivity and the reliability of the pressure sensitive portion from being lowered without adhering to and mixing with the gel.
Further, since the escape groove and the inside of the case are communicated with each other by the ventilation groove formed on the lower surface of the cap, air is not enclosed in the escape groove, and the semiconductor pressure sensor is mounted on the circuit board such as the engine controller. Even if it is installed in a place where the temperature becomes high, such as in the engine room, it is possible to avoid the situation where the enclosed air expands as the temperature in the engine room rises, and the sensitivity and reliability of the pressure-sensitive part are reduced. Can be prevented.

[Brief description of drawings]

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

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

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

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

5 is a sectional view taken along the line KK of FIG.

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

[Explanation 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 Relief Groove 23 Ventilation Groove

Claims (1)

[Claims] 1. A sensor element having a pressure-sensitive diaphragm, a bonding wire connecting the sensor element and a hybrid circuit board, a gel coated so as to cover the surfaces of the sensor element and the bonding wire, and The hybrid circuit board is provided with a case that is adhered and fixed so as to surround the sensor element and the bonding wire, and a cap that has a hole for pressure introduction and that is adhered and fixed to the upper surface of the case is further provided. An escape groove formed on the upper surface of the case to prevent the adhesive for fixing the cap from flowing out into the case,
A semiconductor pressure sensor, comprising: a vent groove formed on a lower surface of the cap for communicating the escape groove with the inside of the case.