JP2003014568A - Semiconductor pressure sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a semiconductor pressure sensor capable of strongly joining a sensor element joining wall part and a semiconductor pressure sensor element and keeping airtightness of both of them. SOLUTION: The direction of attachment of the semiconductor pressure sensor element 1 is reversed to a conventional attaching direction so as to be opposed to a fluid introducing passage 5 to receive the force in the direction pressed to the sensor element joining wall part 3a. By this constitution, the joining durability of the semiconductor pressure sensor element 1 and the sensor element joining wall 3a is enhanced. Further, an electric part housing space 7 can be provided on the side opposite to a sensor element housing space by the reversal of the attaching direction of the semiconductor pressure sensor element 1, and at least a part of a signal processing circuit is housed in the electric part housing space 7. As a result, the output signal of the semiconductor pressure sensor element 1 is processed within a sensor case 3 in the immediate vicinity of a generation source and made hard to receive obstruction with respect to extraneous noise to make it possible to enhance the reliability of the output signal.

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 device which detects fluid pressure by a semiconductor pressure sensor element and outputs it as an electric signal.

[0002]

2. Description of the Related Art In the prior art, a sensor element joining wall portion of a sensor case accommodating and joining a semiconductor pressure sensor element and a semiconductor pressure sensor element by the pressure of a fluid to be measured introduced from a fluid introduction path. Was receiving a force in the direction of separation. One of the conventional examples is Japanese Patent Laid-Open No. 2000-199.
No. 725 publication.

[0003]

However, in the conventional semiconductor pressure sensor device having such a structure, there is a possibility that the sensor element joining wall portion and the semiconductor pressure sensor element may be separated from each other by the pressure of the fluid to be measured, There was a risk that the airtightness of both could not be maintained.

An object of the present invention is to provide a semiconductor pressure sensor device capable of strengthening the bonding between the sensor element bonding wall portion and the semiconductor pressure sensor element and maintaining a high airtightness therebetween.

Another object of the present invention is to provide an electrical component in which a sensor case accommodates at least a part of an electrical component forming a signal processing circuit on a side surface side opposite to a side surface of a sensor element joining wall portion. An object of the present invention is to provide a semiconductor pressure sensor device having a storage space.

Another object of the present invention is to protect the semiconductor pressure sensor element from high voltage due to frictional charging of the fluid itself,
It is an object of the present invention to provide a highly reliable semiconductor pressure sensor device by protecting a signal processing circuit built in an electric component housing space from external noise.

Still another object of the present invention is to provide a semiconductor pressure sensor device which is inexpensive, small in size and highly reliable.

[0008]

SUMMARY OF THE INVENTION The present invention is directed to a semiconductor pressure sensor element integrally having a diaphragm portion having diffusion resistance and a diaphragm support portion for supporting an outer peripheral portion of the diaphragm portion, and a diaphragm support for the semiconductor pressure sensor element. Pressure sensor having a sensor case for accommodating a semiconductor pressure sensor element, which has a fluid introduction path for guiding a fluid to be measured, which is an object of pressure measurement, to a sensor element joining wall section to which a section is joined and a diaphragm section The device is targeted for improvement.

In the present invention, the fluid to be measured acts on the semiconductor pressure sensor element in the direction in which the pressure of the fluid to be measured pushes the semiconductor pressure sensor element toward the sensor element bonding wall portion through the fluid introduction path of the sensor case. It is configured so as to lead to the diaphragm part. With this configuration, the sensor element joining wall portion and the semiconductor pressure sensor element can be joined firmly and the airtightness therebetween can be maintained high. Therefore, the semiconductor pressure sensor device is effective in terms of manufacturability and reliability for long-term use.

Further, in the present invention, a signal processing circuit for processing at least an output signal of the semiconductor pressure sensor element is further provided, and the sensor case is joined to the diaphragm supporting portion of the sensor element joining wall portion. An electric component storage space for accommodating at least a part of the electric components forming the signal processing circuit is further provided on the other side face side opposite to the one side face. As a result, since the output signal of the semiconductor pressure sensor element is processed in the immediate vicinity of the source, it is less likely to be disturbed by external noise, which is effective for the reliability of the output signal of the semiconductor pressure sensor device.

In the present invention, the sensor case is
A first peripheral wall portion which is located on one side surface side of the sensor element joining wall portion and surrounds the semiconductor pressure sensor element to form a sensor element housing space therein, and on the other side surface side of the sensor element joining wall portion. And a second peripheral wall portion located inside and forming an electric component storage space. The sensor element joining wall portion is provided with a through hole that communicates the space formed between the semiconductor pressure sensor element joined to one side surface and the one side surface with the electrical component storage space. For the first lid member that closes the opening of the first peripheral wall portion,
The second lid member that integrally forms the tubular body that constitutes a part of the fluid introduction path and closes the opening of the second peripheral wall portion is provided on the second peripheral wall portion so as not to make the electrical component storage space airtight. Install it against. With this configuration, the sensor element housing space is covered with the pressure of the fluid to be measured. Further, since the second lid member is attached to the second peripheral wall portion so as not to keep the electric component storage space airtight, the electric component storage space is kept at atmospheric pressure, and the electric component storage space is accommodated by the through hole. The space surrounded by the sensor element joining wall communicating with the space and the semiconductor pressure sensor element is also kept at atmospheric pressure. As a result, the diaphragm portion bends according to the amount of pressure of the fluid to be measured. Therefore, the pressure of the fluid to be measured can be measured, and the semiconductor pressure sensor device functions properly.

Further, in the present invention, the second lid member is made of a metal material and is configured to be electrically connected to the ground when in use. Similarly, the first lid member is made of a metal material, and is configured to be electrically connected to the ground when in use. The electrical component includes an integrated circuit for signal processing, and the integrated circuit is a first
It is arranged so as to be located between the cover member and the second cover member. With this configuration, it is possible to protect the semiconductor pressure sensor element from a high voltage due to frictional electrification of the fluid itself, and to protect the integrated circuit from external noise. This improves the reliability of the semiconductor pressure sensor device.

Further, in the present invention, a plurality of surface-mounting electrodes for surface-mounting the electric component are formed on the other side surface of the sensor element joining wall portion, and the electrode of the electric component is formed by the plurality of surface-mounting electrodes. Electrically and mechanically connected on top. As a result, the surface mount electronic component is housed in the electric component housing space, and it is possible to obtain an inexpensive, compact, highly reliable semiconductor pressure sensor device.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1A is a front view of the semiconductor pressure sensor device according to the embodiment of the present invention.
1B is a cross-sectional view taken along the line BB of FIG.
1C is a rear view of the semiconductor pressure sensor device shown in FIG. FIG. 2 is a perspective view of the first lid member 13 and the tubular body 11 that close the opening that forms the sensor element housing space of the semiconductor pressure sensor device shown in FIG. Note that FIG.
(A) and (C) show the lid member 1 for easy understanding.
5 and the cylindrical body 11 and the lid member 13 are removed. In FIG. 1, reference numeral 1 indicates a semiconductor pressure sensor element. This semiconductor pressure sensor element 1
Is formed of a Si semiconductor substrate, and is integrally formed by the diaphragm portion 1a and the diaphragm support portion 1b. The diaphragm portion 1a has a rectangular flat plate shape, and a resistance bridge circuit including four resistance elements and a resistance circuit including one resistance element are formed on the surface thereof. The surface on which the resistance bridge circuit and the like are formed is covered with an insulating resin layer for protection. The diaphragm support portion 1b has a rectangular tubular shape, and supports the outer peripheral portion of the diaphragm portion 1a on the back surface side. The diaphragm support portion 1b is attached to the sensor case 3 in a manner described later.

Reference numeral 3 indicates a sensor case. The sensor case 3 has a sensor element joining wall portion 3a, a first peripheral wall portion 3b, and a second peripheral wall portion 3c. The sensor element joining wall portion 3a has a substantially quadrangular plate shape, and a through hole 9 having a circular cross section is formed in the center thereof. An end surface of the diaphragm support portion 1b of the semiconductor pressure sensor element 1 is airtightly joined to one side surface of the sensor element joining wall portion 3a so that one opening of the through hole 9 is covered with the semiconductor pressure sensor element 1. ing. Further, a signal processing circuit 6 described later is formed on the other side surface of the sensor element joining wall portion 3a.

The first peripheral wall portion 3b has a frame shape having a substantially quadrangular outline, and has an inner wall portion 3f and an outer wall portion 3g.
And have. The inner wall portion 3f is joined to one side surface side of the sensor element joining wall portion 3a so as to surround the semiconductor pressure sensor element 1. The outer wall portion 3g is joined to the inner wall portion 3f so as to form a step with the inner wall portion 3f. As a result, the sensor element housing space 4 for housing the semiconductor pressure sensor element 1 is formed inside the first peripheral wall portion 3b. Outer wall part 3g
A plurality of external connection electrodes 23 are formed on the outer surface around the opening on the side opposite to the side where the sensor element joining wall 3a is located. Further, the step portion 3 is provided in the opening of the outer wall portion 3g.
d is formed, and the first lid member 13 is airtightly fitted to the step portion 3d so as to close the opening of the first peripheral wall portion 3b. A through hole is formed in the center of the first lid member 13, and a cylindrical tubular body 11 forming a part of the fluid introduction path 5 is integrally provided around the through hole. . The fluid introduction path 5 plays a role of guiding the fluid to be measured, which is a pressure measurement target, in the vicinity of the diaphragm portion 1a of the semiconductor pressure sensor element 1.

The second peripheral wall portion 3c has a frame shape with a substantially quadrangular outline, and is located on the other side surface side of the sensor element joining wall portion 3a so as to surround the signal processing circuit 6. . The signal processing circuit 6 is a circuit for processing the output signal of the semiconductor pressure sensor element, and in this example, two electric components 17 including an integrated circuit for signal processing are mounted on the signal processing circuit 6. As a result, inside the second peripheral wall portion 3c, the electric component housing space 7 for housing the electric component 17 and communicating with the through hole 9 is formed. A plurality of external connection electrodes 25 are formed on the outer surface of the second peripheral wall portion 3c around the opening on the side opposite to the side where the sensor element joining wall portion 3a is located. Further, a step portion 3e is formed in the opening of the second peripheral wall portion 3c, and the second lid member 15 is slightly formed in the step portion 3e so as to close the opening of the second peripheral wall portion 3c. It is fitted so that it does not become airtight with a large gap. As described above, since the second peripheral wall portion 3c and the second lid member 15 are not in an airtight state, the electric component storage space 7 is maintained at the atmospheric pressure, and the through hole 9 communicates with the electric component storage space 7. Wall 3 for joining sensor elements
The space surrounded by a and the semiconductor pressure sensor element 1 is also kept at atmospheric pressure. With the above configuration, the pressure of the fluid to be measured that has flowed into the sensor element housing space 4 through the fluid introduction path 5 acts in the direction in which the semiconductor pressure sensor element 1 is pressed against the sensor element joining wall portion 3a of the sensor case 3 and the diaphragm. The portion 1a bends according to the amount of pressure of the fluid to be measured. Therefore, the bonding between the sensor element bonding wall portion 3a and the semiconductor pressure sensor element 1 is strengthened, and the airtightness of both is maintained.

One or both of the first lid member 13 and the second lid member 15 are made of a metal material and are electrically connected to the ground in a used state. The first lid member 13 and the second lid member 15 are formed of an insulator such as plastic or ceramics instead of a metal material,
The surface may be made conductive by metal vapor deposition, plating or conductive coating.

The signal processing circuit 6 formed on the other side surface of the sensor element bonding wall portion 3a includes a plurality of surface mounting electrodes 19 for surface mounting the electric component 17.
The electrode 17a of the electric component 17 is a plurality of surface mounting electrodes 19
Are electrically and mechanically connected to some of the electrodes.
Further, a plurality of wiring patterns 21 are formed on the inner wall portion 3f of the first peripheral wall portion 3b. The semiconductor pressure sensor element 1 is connected to a plurality of wiring patterns 21 via a plurality of bonding wires 21a, and the wiring pattern 2
1 is electrically connected to a part of the plurality of surface mounting electrodes 19 and a part of the conductor wire portion 27 formed on the outer surface of the sensor case 3. Thereby, the output signal generated from the semiconductor pressure sensor element 1 is transmitted to the electric component 17
Be guided to. Then, the output signal subjected to the signal processing by the electric component 17 is guided to the external connection electrode 23 or 25 through a part of the surface mounting electrode 19 and a part of the conductive wire portion 27, and is output to the outside. As a result, the surface mount electronic component is housed in the electric component housing space, and it is possible to obtain a semiconductor pressure sensor device that is inexpensive, small in size, and resistant to external noise, and highly reliable.

[0020]

According to the present invention, the semiconductor pressure sensor element is configured to receive a force in the direction of being pressed against the sensor element joining wall portion by the pressure of the fluid to be measured introduced from the fluid introduction path. As a result, the sensor element bonding wall portion and the semiconductor pressure sensor element can be firmly bonded to each other and the airtightness therebetween can be maintained high. Therefore, the durability of the joining between the semiconductor pressure sensor element and the sensor element joining wall portion is improved, which is effective for the manufacturability of the semiconductor pressure sensor device and the reliability for long-term use.

Further, in the present invention, by mounting the semiconductor pressure sensor element by reversing the mounting direction of the semiconductor pressure sensor element to the conventional direction, it is possible to provide an electric component accommodating space on the opposite side of the sensor element accommodating space. At least a part of the circuit can be stored in the electric component storage space. This allows the output signal of the semiconductor pressure sensor element to be processed in the sensor case in the immediate vicinity of the source,
The reliability of the output signal can be improved by making it less likely to be disturbed by external noise. Furthermore, by forming a lid member that closes the openings of these spaces with a metal material and grounding it to the ground, the shielding effect against external noise can be enhanced and the reliability of the output signal can be improved.

[Brief description of drawings]

1A is a front view of a semiconductor pressure sensor device according to an embodiment of the present invention, and FIG. 1B is a BB line in FIG. 1A.
It is a line sectional view, and (C) is a rear view of the semiconductor pressure sensor device shown in Drawing 1 (A).

FIG. 2 is a perspective view of a first lid member and a cylinder that close an opening that forms a sensor element housing space of the semiconductor pressure sensor device shown in FIG.

[Explanation of symbols]

1 Semiconductor pressure sensor element 1a Diaphragm part 1b Diaphragm support 3 sensor case 3a Wall for joining sensor element 3b First peripheral wall portion 3c Second peripheral wall portion 5 Fluid introduction path 7 electrical parts storage space 9 through holes 11 cylinder 13 First lid member 15 Second lid member 17 electrical components 17a Electrode of electric component 19 Surface mounting electrodes 21 Wiring pattern 21a Bonding wire

   ─────────────────────────────────────────────────── ─── Continued front page    F term (reference) 2F055 AA40 BB20 CC02 DD04 EE14                       FF21 FF38 GG12 GG25 HH05                 4M112 AA01 CA03 CA04 CA06 CA12                       CA13 CA15 DA08 EA03 FA07

Claims (6)

[Claims] 1. A semiconductor pressure sensor element integrally including a diaphragm portion having a diffusion resistance and a diaphragm support portion supporting an outer peripheral portion of the diaphragm portion, and the diaphragm support portion of the semiconductor pressure sensor element are joined together. In a semiconductor pressure sensor device comprising a sensor element joining wall portion and a fluid introduction path for guiding a fluid to be measured which is a target of pressure measurement to the diaphragm portion, and a sensor case accommodating the semiconductor pressure sensor element, The fluid introduction path of the sensor case is the fluid to be measured so that the pressure of the fluid to be measured acts on the semiconductor pressure sensor element in a direction to press the semiconductor pressure sensor element toward the sensor element joining wall portion. A semiconductor pressure sensor device, wherein the semiconductor pressure sensor device is configured to be guided to the diaphragm portion. 2. A signal processing circuit for processing at least an output signal of the semiconductor pressure sensor element, wherein the sensor case has one side surface to which the diaphragm support portion of the sensor element joining wall portion is joined. 2. The semiconductor pressure sensor device according to claim 1, further comprising an electric component storage space for accommodating at least a part of electric components constituting the signal processing circuit, on the other side surface located on the opposite side. 3. The sensor case includes a first peripheral wall portion located on the one side surface side of the sensor element joining wall portion and surrounding the semiconductor pressure sensor element to form a sensor element housing space inside. A second peripheral wall portion that is located on the other side surface side of the sensor element joining wall portion and that forms the electric component storage space therein, and the sensor element joining wall portion includes: A through hole that connects the space formed between the semiconductor pressure sensor element bonded to one side surface and the one side surface and the electric component storage space is formed, and the first peripheral wall portion is formed. For the first lid member that closes the opening,
The second lid member that is integrally provided with a cylindrical body that constitutes a part of the fluid introduction path and that closes the opening of the second peripheral wall portion does not make the electrical component storage space airtight. The semiconductor pressure sensor device according to claim 2, which is attached to the second peripheral wall portion. 4. The semiconductor pressure sensor device according to claim 3, wherein the second lid member is formed of a metal material and is configured to be electrically connected to a ground in a used state. 5. The first lid member is formed of a metal material and is configured to be electrically connected to a ground in a use state, and the electric component includes an integrated circuit for signal processing. The semiconductor pressure sensor device according to claim 4, wherein the integrated circuit is disposed so as to be located between the first lid member and the second lid member. 6. A plurality of surface-mounting electrodes for surface-mounting the electric component are formed on the other side surface of the sensor element joining wall portion, and the electrodes of the electric component are the plurality of electrodes. The semiconductor pressure sensor device according to claim 2, wherein the semiconductor pressure sensor device is electrically and mechanically connected to the surface mounting electrode.