JP3149396B2 - Manufacturing method of 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 pressure sensor for detecting a pressure of a fluid, and more particularly to a method of manufacturing a pressure sensor for receiving a fluid pressure by a semiconductor element and electrically detecting the pressure.

[0002]

2. Description of the Related Art Conventionally, a semiconductor type pressure sensor has been provided as a small-sized pressure sensor capable of accurately measuring the pressure of gas. As shown in a vertical sectional view of FIG. 6, a conventional semiconductor pressure sensor includes an outer frame 1 of a pressure sensor and a gas inlet 2 formed integrally with the outer frame 1 and having a thin tip 3.
And a sensor case 6 containing a silicon substrate 4 is housed in the outer frame 1. A silicon film 5 having a thickness of several microns is formed on the silicon substrate 4 by etching, and a semiconductor resistor whose resistance value changes due to mechanical strain is formed on the silicon film 5. The sensor case 6 is provided with a printed circuit board 8 on which an air introduction portion 7 is formed and on which an electric circuit such as an amplifier circuit is formed. An input / output terminal 9 is provided on the printed circuit board 8, housed in the outer frame 1, and molded with a synthetic resin 10. The sensor case 6 is bonded to the inside of the outer frame 1 with an adhesive 11, and a gel 12 is provided on the silicon film 5 so as not to directly contact dust or moisture contained in the gas.
Is coated. The electric circuit formed on the printed circuit board 8 has a function of amplifying the change in the resistance value. The input / output terminals 9 are a power supply terminal for supplying power to an electric circuit on the printed circuit board 8 and a resistor on the silicon film 5, an output terminal for amplifying and outputting a change in resistance value, and a ground terminal. .

In the measurement method of this semiconductor type pressure sensor, first, when a gas pressure is applied from the gas introduction unit 2, a mechanical difference is caused between the atmospheric pressure and the gas pressure applied from the air introduction unit 7 to the silicon film 5. Causes distortion. This distortion is proportional to the pressure difference between the gas pressure and the atmospheric pressure. When the silicon film 5 is distorted, the value of the resistance formed on the silicon film 5 changes in proportion to the magnitude of the distortion. By detecting the change in the resistance value, amplifying and outputting the amplified value, the differential pressure between the gas pressure and the atmospheric pressure can be measured.

[0004]

In the case of the above-mentioned prior art, the joint between the sensor case 6 and the outer frame 1 is formed by bonding the flat joint end face of the sensor case 6 to the flat bottom surface of the outer frame 1. Therefore, the adhesive strength is low, the airtightness is not high, and there is a problem in terms of safety in measuring the pressure of toxic gas, flammable gas, and the like. In addition, since flat surfaces are bonded to each other, there is no reference for positioning, and there is a problem that it is difficult to accurately bond the position of the sensor case to a predetermined position.

The present invention has been made in view of the above-mentioned problems of the prior art, and can be easily reduced in size, has high bonding strength between the sensor case and its housing member, and has good airtightness at the bonding portion. It is an object to provide a method for manufacturing a high pressure sensor.

[0006]

SUMMARY OF THE INVENTION The present invention provides a semiconductor pressure sensor element, a sensor case accommodating and holding the pressure sensor element, and a sensor case electrically connected to the pressure sensor element and integrated with the sensor case. A pressure sensor including an insert-molded lead frame, a printed circuit board on which the lead frame is surface-mounted, and a housing containing the sensor case surface-mounted on the printed circuit board. The sensor case is a pressure sensor integrally provided with a pressure introducing cylinder for introducing pressure to the pressure sensor element, and the lead frame extends in a protruding direction of the pressure introducing cylinder. Further, the sensor case is a pressure sensor embedded in a resin in the housing, and a pressure introducing cylinder of the sensor case projects from the resin.

Further, the present invention has a semiconductor pressure sensor element, and a sensor case which houses and holds the pressure sensor element, wherein a lead frame electrically connected to the pressure sensor element is integrated with the sensor case. A method for manufacturing a pressure sensor, wherein the pressure sensor is surface-mounted on a printed circuit board by insert molding, and the sensor case surface-mounted on the printed circuit board is housed in a housing together with the printed circuit board. Further, a ridge is formed over the entire periphery at one joint portion of the sensor case and the housing, and a concave portion is formed at the other joint portion of the sensor case and the housing, at which the ridge fits over the entire periphery. A method of manufacturing a pressure sensor in which the sensor case is fitted into the housing by fitting the ridge and the recess into each other with an adhesive or the like. Alternatively, the joining portions of the sensor case and the housing are brought into contact with each other, and are welded by ultrasonic vibration or the like and joined in an airtight state.

In the pressure sensor according to the present invention, the sensor case and its housing member are surface-mounted on a circuit board by a lead frame and housed in a housing, so that the airtightness and strength are extremely high and the structure is downsized. Can be done.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. FIGS. 1 to 3 show an embodiment of the present invention. In the pressure sensor of this embodiment, a sensor element 15 made of a Si semiconductor has a sensor case 17.
It is provided inside. The sensor element 15 is adhered to the glass base 14. In addition, glass base 1
4 is fixed in the mounting recess 18 of the sensor case 17 by an adhesive 16 made of a silicon-based resin. The sensor case 17 is formed of a heat-resistant resin such as PPS resin, and the lead frame 20 is provided by insert molding. A gold wire 22 is bonded between one end of the lead frame 20 and the sensor element 15. An atmospheric pressure introducing cylinder 24 for introducing atmospheric pressure is formed integrally with the sensor case 17, and a mounting recess 18 on the surface side of the sensor element 15 opposite to the atmospheric pressure introducing cylinder 24.
Is filled with a potting agent 26 such as polyurethane gel or silicon gel, and the sensor element 15 and the gold wire 22 are embedded therein.

The sensor case 17 includes a lead frame 2
The printed circuit board 28 is attached via the reference numeral 0, and the terminal 30 is fixed to the printed circuit board 28. The sensor case 17 is joined to a central portion of a housing 32 which is a housing member formed of PBT resin or the like by an epoxy adhesive 34. In this joint portion, a V-shaped concave groove 36 is formed over the entire periphery of the end surface on the sensor case 17 side, and a convex ridge 40 is formed on the inner bottom surface 38 of the housing 32. 36. Outside the ridge 40 of the housing 32, a side wall 50 is formed so as to surround a side edge of the sensor case 17, and a corner of the end face of the sensor case 17 is joined by an adhesive 34.

The sensor case 17 includes a potting agent 26.
The surface side of the sensor element 15 covered with
Is mounted facing the pressure introduction cylinder 46 side. In the housing 32, the sensor case 17 is filled with a silicone resin filler 42 and a soft epoxy resin filler 44 filled thereon.
And the terminal 30 are formed in a protruding state.

According to the pressure sensor of this embodiment, the connection between the sensor case 17 and the housing 32 is
Are joined via the adhesive 34 by fitting with the concave groove 36, so that the joining strength is high, the alignment at the time of assembly is easy, and the attachment is easy.

The pressure sensor of the present invention is not limited to the above-described embodiment, and the ridge 40 formed on the housing 32 may be fitted and fixed to the concave groove 36 of the sensor element by ultrasonic welding. At this time, the shapes of the concave groove 36 and the ridge 40 are as shown in FIG.
As shown in FIG. 5A, the tip of the ridge 40 may be melted and welded to the U-shaped groove 36 by ultrasonic vibration.
As shown in (B), the ridge 40 may be ultrasonically welded to the concave portion 36 formed by the notch. In the case of ultrasonic welding, it is preferable to form a through hole in the printed circuit board 28 in order to bring the ultrasonic element to be welded into contact with the sensor case 17.

Accordingly, even when the sensor case 17 and the housing 32 cannot be bonded to each other with the adhesive, the resin is reliably melted and fixed, so that the mounting strength can be extremely increased. In addition, since no adhesive is used, the workability of the mounting work is good and the handleability is also good.

The concave and convex ridges of the pressure sensor of the present invention may be formed in either the sensor case or the housing.
Or a W-shaped portion, and a convex portion formed of an L-shaped corner portion,
It may be one that engages with a concave portion consisting of a corner of a mold.

[0016]

According to the pressure sensor of the present invention, when the sensor case is housed in the housing, the sensor case which is surface-mounted on the substrate by the lead frame is housed, so that the size can be reduced as a whole and the medium to be measured can be reduced. Without leaking out of the sensor, safety and reliability can be improved. In addition, the mounting can be performed more easily and accurately by matching the concave and convex portions.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a pressure sensor according to a first embodiment of the present invention.

FIG. 2 is a partially broken front view of a sensor case of the pressure sensor according to the first embodiment.

FIG. 3 is a partially broken bottom view of a sensor case of the pressure sensor according to the first embodiment.

FIG. 4 is a plan view of the easing of the pressure sensor of the first embodiment.

FIG. 5 is a partial longitudinal sectional view showing a joint between a sensor case and a housing of a pressure sensor according to another embodiment of the present invention.

FIG. 6 is a longitudinal sectional view showing a conventional technique of the present invention.

[Explanation of symbols]

 15 sensor element 17 sensor case 32 housing 36 concave groove 40 convex line

Continuation of the front page (56) References JP-A-4-155970 (JP, A) JP-A-4-69535 (JP, A) JP-A-62-55536 (JP, A) JP-A-63-188535 (JP) , U) Jpn. Sho 62-192234 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) G01L 9/04

Claims (2)

(57) [Claims] A semiconductor pressure sensor element, a sensor case accommodating and holding the pressure sensor element, and the sensor
The housing in which the case is mounted
All around the joint between the case and one of the housings
The sensor case and the housing form a ridge.
The above-mentioned ridge fits over the entire circumference of the other part of the joint
The sensor case is mounted on the printed circuit board.
Surface mounted, the sensor case together with the printed circuit board accommodated in the housing, fitting the ridge and recess
And brought into contact with each other.
A method for manufacturing a pressure sensor, wherein the pressure sensor is bonded in a dense state . 2. A pressure sensor device comprising : a semiconductor pressure sensor element;
Sensor case containing and holding the sensor element and this sensor
The housing in which the case is mounted
All around the joint between the case and one of the housings
The sensor case and the housing form a ridge.
The above-mentioned ridge fits over the entire circumference of the other part of the joint
A concave portion to be electrically connected to the pressure sensor element.
Lead frame to be integrated with the sensor case.
Form-mold and display the above lead frame on the printed circuit board.
Surface-mounted and mounted on the printed circuit board
Put the case together with the printed circuit board in the housing
In the housing, and the sensor case is
A method of manufacturing a pressure sensor, wherein a ridge and a recess are fitted and bonded .