JP6728980B2 - Method of manufacturing pressure sensor - Google Patents

Description

The present invention relates to a manufacturing method of the pressure sensor equipped with a sensor chip on a diaphragm formed in the stem.

BACKGROUND ART Conventionally, there has been proposed a pressure sensor having a metal stem having a diaphragm formed therein and a sensor chip mounted on the diaphragm via a joining member. Specifically, the metal stem has a bottomed cylindrical shape in which a recess is formed from one end side to the other end side, and the recessed part is formed on the other end side to form the bottom surface of the recessed part and the recessed part. A diaphragm is formed in a portion between the bottom surface and the bottom surface. The joining member is arranged in the recess, and the sensor chip is mounted on the diaphragm via the joining member.

Such a pressure sensor is manufactured by preparing a metal stem having the recess and the recess, pouring the bonding member into the recess, and mounting the sensor chip on the bonding member.

JP, 2008-82825, A

However, in the above pressure sensor, since the joining member is simply poured into the recess, the surface of the joining member (that is, the surface on which the sensor chip is mounted) may be inclined with respect to the diaphragm. Therefore, if the sensor chip is mounted on the surface of such a joining member, the sensor chip may be tilted with respect to the diaphragm, and the detection accuracy may decrease.

The present invention has been made in view of the above point, the detection accuracy and to provide a manufacturing method of the pressure sensor can be suppressed from being lowered.

According to claim 1 for achieving the above object, in a method of manufacturing a pressure sensor for detecting pressure, a bottomed cylindrical stem (10) having a recess (11) formed from one end to the other end. And forming a recess (12) on one surface (10a) facing the recess at the other end of the stem, so that the portion between the bottom of the recess and the bottom of the recess can respond to the pressure. Forming a deformable diaphragm (13), disposing a joining member (20) in the recess, and outputting a sensor signal according to the deformation of the diaphragm on the diaphragm via the joining member. (30) is carried out, and the joint member is arranged in the recess, thereby filling the recess and disposing the joint member so as to protrude from the recess. The joining member protruding from the recess is removed so that the portion exposed from the portion and the one surface become a flat surface.

According to this, since the part of the joining member exposed from the recess and the one surface are flat, when the sensor chip is mounted on the diaphragm via the joining member, the sensor chip is It is possible to suppress tilting with respect to, and it is possible to suppress deterioration in detection accuracy.

The reference numerals in parentheses in the above description and the claims indicate the correspondence between the terms described in the claims and the concrete objects and the like that exemplify the terms described in the embodiments described later. ..

It is sectional drawing of the pressure sensor in 1st Embodiment. It is an enlarged view of the diaphragm vicinity in FIG. FIG. 3 is a cross-sectional view showing a manufacturing process of the pressure sensor shown in FIG. 1. FIG. 4 is a cross-sectional view showing the manufacturing process of the pressure sensor following FIG. 3.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In each of the following embodiments, the same or equivalent portions will be denoted by the same reference numerals for description.

(First embodiment)
The first embodiment will be described with reference to the drawings. The pressure sensor of the present embodiment is preferably applied to detect the pressure of fuel or brake fluid of an automobile, for example, and is particularly preferably used as a high pressure sensor that detects a high pressure of about 20 to 300 MPa. Is.

As shown in FIG. 1, the pressure sensor has a metal stem 10. The metal stem 10 is made of stainless steel or the like such as SUS430, and is recessed from one end (that is, the end on the lower side of the paper in FIG. 1) toward the other end (that is, the upper end on the paper in FIG. 1). 11 is formed to have a bottomed cylindrical shape.

Further, as shown in FIGS. 1 and 2, the metal stem 10 has a recess 12 formed on one surface 10 a facing the bottom surface of the recess 11. As a result, the metal stem 10 is provided with the diaphragm 13 that is formed between the bottom surface of the recess 11 and the bottom surface of the recess 12 and is deformable by pressure. In other words, the recessed portion 11 and the recessed portion 12 are formed such that the portion between the bottom surfaces thereof is deformable by pressure.

The bottom surface of the recess 11, the bottom surface of the recess 12, and the one surface 10a are formed to be parallel to each other. That is, the one surface 10a and the diaphragm 13 formed by the portion between the bottom surface of the recess 11 and the bottom surface of the recess 12 are parallel to each other.

A joint member 20 made of glass, a silicone adhesive, or the like is arranged in the recess 12. Specifically, the joining member 20 is arranged so as to fill the hollow portion 12, and is arranged so as to form a flat surface together with the one surface 10a. In other words, the joining member 20 has a thickness equal to the depth of the recess 12, and is arranged so as to completely embed the recess 12 and not to protrude from the recess 12.

The sensor chip 30 is mounted on the joining member 20. That is, the sensor chip 30 is mounted on the diaphragm 13 via the joining member 20. As the sensor chip 30, when the diaphragm 13 is deformed by the pressure of the pressure medium introduced into the recess 11, a strain gauge (not shown) that outputs a sensor signal according to the deformation is used.

Further, as shown in FIG. 1, the metal stem 10 is provided with a stepped portion 14 having a larger outer diameter on one end side than on the other end side (that is, the diaphragm 13 side). The metal stem 10 is fixed by screwing the screw member 40 to the housing 50, which will be specifically described later.

The housing 50 is directly attached to the fuel pipe to be attached, and has an attachment screw 51 formed on the outer peripheral surface thereof. A pressure introducing passage 52 communicating with the recess 11 of the metal stem 10 is formed inside the housing 50. The pressure introducing passage 52 allows the fuel pipe to flow when the housing 50 is attached to the fuel pipe. The pressure medium can be introduced into the recess 11 from the inside through the pressure introduction passage 52.

The screw member 40 has a cylindrical shape that covers the outer periphery of the metal stem 10, and a male screw portion 41 is formed on the outer peripheral surface thereof. Further, a female screw portion 53 having a shape corresponding to the male screw portion 41 is formed in a portion of the housing 50 corresponding to the male screw portion 41. The screw parts 41 and 53 are screwed together.

As a result, the pressing force from the screw member 40 is applied to the stepped portion 14 of the metal stem 10, and the metal stem 10 is pressed and fixed to the housing 50. Further, this pressing force seals the communicating portion between the recess 11 and the pressure introducing passage 52, that is, the boundary between the recess 11 side of the metal stem 10 and the pressure introducing passage 52 side of the housing 50.

A ceramic substrate 60, which is a circuit substrate, is bonded and fixed to the screw member 40 so as to surround the sensor chip 30 in the housing 50. An IC chip 61 having a signal processing circuit and the like formed thereon is arranged on the ceramic substrate 60, and the ceramic substrate 60 and the IC chip 61 are electrically connected via a bonding wire 63.

Further, the ceramic substrate 60 and the sensor chip 30 are electrically connected by a bonding wire 64. Then, a pin 65 for electrically connecting to the connector terminal 70 is joined to the ceramic substrate 60 with silver solder or the like.

The connector terminal 70 is an assembly (ASSY) in which the terminal 71 is insert-molded in the resin 72. The terminal 71 and the ceramic substrate 60 are electrically connected via the pin 65. As a result, the output from the sensor chip 30 is transmitted from the bonding wire 64 to the terminal 71 via the pin 65, and is transmitted to the ECU of the automobile or the like via the wiring member via the terminal 71.

Further, the connector terminal 70 is pressed against the lower surface of the connector case 80 to be pressed against the screw member 40 and fixedly held. In addition, although one terminal 71 is shown in FIG. 1, a plurality of terminals for input, output, etc. are actually provided.

The connector case 80 forms the outer shape of the connector terminal 70, and is inserted into an opening portion on one end side (the other end side of the pressure introduction passage 52) of the housing 50 via an O-ring 90 to cover the opening end of the housing 50. It is integrated by tightening. That is, the connector case 80 constitutes a package to be assembled in the housing 50, and has a function of protecting the sensor chip 30, the electrical connection portion and the like inside the package from moisture and mechanical external force. The connector case 80 is made of PPS (polyphenylene sulfide) or the like, which is highly hydrolyzable.

The above is the configuration of the pressure sensor in the present embodiment. Next, a method of manufacturing such a pressure sensor will be described.

First, as shown in FIG. 3A, a metal stem 10 having a recess 11 is prepared. Next, as shown in FIG. 3( b ), a portion of the concave portion 11 opposite to the bottom surface is removed by cutting, polishing or the like using a cutting tool (not shown) to remove the metal stem 10 from the other end portion side. The one surface 10a is formed. At this time, with the bottom surface of the recess 11 as a reference surface, the length between the bottom surface of the recess 11 and the one surface 10a becomes a desired length, and the bottom surface of the recess 11 and the one surface 10a are parallel to each other. Form.

Next, as shown in FIG. 3C, the recess 12 is formed on the one surface 10a by using a cutting tool (not shown). Specifically, the bottom surface of the recess 11 is used as a reference surface, and the length between the bottom surface of the recess 11 and the bottom surface of the recess 12 becomes a desired length (that is, the thickness of the diaphragm 13 becomes a predetermined thickness). The recess 12 is formed so that the bottom of the recess 11 and the bottom of the recess 12 are parallel to each other. That is, in this embodiment, when forming the one surface 10a and the recessed portion 12, the bottom surface of the recess 11 is processed as the reference surface.

Subsequently, as shown in FIG. 4A, the recess 12 is filled with the joining member 20. In this step, first, the joining member 20 is filled with the dispenser or the like so as to protrude from the recess 12. After that, by moving an unillustrated squeegee or the like along the one surface 10a, the recessed portion 12 is filled with the joining member 20 while removing the portion protruding from the recessed portion 12. That is, the joint member 20 is filled in the recess 12 so that the one surface 10a and the portion of the joint member 20 exposed from the recess 12 form a flat surface.

Next, as shown in FIG. 4B, after preparing the sensor chip 30 manufactured by a well-known semiconductor manufacturing process, the sensor chip 30 is arranged on the one surface 10 a of the metal stem 10. After that, as shown in FIG. 4C, the sensor chip 30 is moved (that is, slid) along the one surface 10 a to arrange the sensor chip 30 on the bonding member 20. As a result, the sensor chip 30 is mounted on the diaphragm 13 via the joining member 20. The sensor chip 30 is attracted and fixed by a collet or the like, and is displaced along with the displacement of the collet.

Although not shown in the drawings, the pressure sensor shown in FIG. 1 is manufactured by preparing the screw member 40, the housing 50, the connector case 80, and the like and appropriately assembling them, although not particularly shown. ..

As described above, in the present embodiment, the joining member 20 arranged in the recess 12 is arranged so as to form a flat surface with the one surface 10a. Therefore, it is possible to prevent the sensor chip 30 from tilting with respect to the diaphragm 13, and it is possible to prevent the detection accuracy from decreasing.

Further, when forming the one surface 10a and the recessed portion 12, the bottom surface of the recessed portion 11 is used as the reference surface. Therefore, when different surfaces are used as reference surfaces when forming the one surface 10a and the depression 12, for example, compared with the case where the one surface 10a is used as the reference surface when forming the depression 12 It is possible to suppress variations in thickness and shape.

Further, when the sensor chip 30 is mounted on the diaphragm 13, after the sensor chip 30 is arranged on the one surface 10a of the metal stem 10, the sensor chip 30 is moved along the one surface 10a so that the sensor chip 30 is mounted on the diaphragm 13. It is equipped with. As a result, the one surface 10a, the bottom surface of the recess 11, and the bottom surface of the recess 12 are parallel to each other, so that it is possible to further suppress the sensor chip 30 from tilting with respect to the diaphragm 13.

The joining member 20 is arranged so as to form a flat surface with the one surface 10 a, and has a thickness equal to the depth of the recess 12. For this reason, it is possible to prevent the thickness of the joining member 20 from varying from product to product, and to prevent the detection accuracy from varying.

(Other embodiments)
The present invention is not limited to the above-described embodiments, but can be appropriately modified within the scope of the claims.

For example, in the first embodiment, the metal stem 10 and the screw member 40 may be integrated, or the metal stem 10, the screw member 40, and the housing 50 may be integrated.

In addition, in the first embodiment, when the sensor chip 30 is mounted on the joining member 20, the sensor chip 30 is not moved along the one surface 10a, but is dropped from directly above the joining member 20. Therefore, it may be mounted on the joining member 20. Even if the pressure sensor is manufactured in this manner, since the joining member 20 is arranged so as to form a flat surface together with the one surface 10a, it is possible to prevent the sensor chip 30 from tilting with respect to the diaphragm 13 and to improve the detection accuracy. It is possible to suppress the decrease.

10 Metal Stem 10a One Surface 11 Recess 12 Recess 13 Diaphragm 20 Joining Member 30 Sensor Chip

Claims (3)

In a method of manufacturing a pressure sensor that detects pressure,
Preparing a bottomed tubular stem (10) having a recess (11) formed from one end to the other end;
By forming a depression (12) on one surface (10a) of the other end of the stem that faces the depression, the portion between the bottom of the depression and the bottom of the depression is deformed according to the pressure. Forming a possible diaphragm (13),
Disposing a joining member (20) in the recess,
Mounting a sensor chip (30) for outputting a sensor signal according to the deformation of the diaphragm on the diaphragm via the joining member,
By disposing the joining member in the recessed portion, the jointing member is arranged so as to fill the recessed portion and protrude from the recessed portion, and the portion of the jointing member exposed from the recessed portion and the portion A method of manufacturing a pressure sensor, comprising removing the joining member protruding from the recess so that one surface becomes a flat surface. By preparing the stem, by preparing the stem in which the recess is formed, and by using a bottom surface of the recess as a reference surface, and removing a portion of the stem opposite to the bottom surface of the recess, And forming the one surface parallel to the bottom surface of the recess,
Said By forming the diaphragm, by forming the recess portion on the one surface of the bottom face of the groove as a reference plane, according to claim 1 to form the recess bottom surface is parallel to the bottom surface of the recess Manufacturing method of pressure sensor. By mounting the sensor chip, by mounting the sensor chip on the one surface, and by moving the sensor chip along the one surface, the sensor chip on the diaphragm via the joining member. The method of manufacturing a pressure sensor according to claim 2 , wherein the mounting is performed.

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