JPH0882563A - Packaging structure of semiconductor pressure sensor - Google Patents

Abstract

PURPOSE: To provide a packaging structure of a semiconductor pressure sensor wherein degradation of measurement accuracy caused by pressure leakage from outer case. CONSTITUTION: A detection element part 10 is formed by bonding a silicon board 1, which has a diaphragm 4 deformable by pressure, to an insulation board 2 which has an electrode part 3. An upper outer case 6 having a pressure inflow through hole 11 and a lower outer case 7 are provided. Further, an air-tight seal part 5 which seals a gap between the silicon board 1 and the upper outer case 6 and has a pressure delivery through hole 13 for delivering pressure from the pressure inflow through hole 11 to the diaphragm 4 is provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to pressure detection in an automobile,
The present invention relates to a semiconductor pressure sensor used for pressure detection of home electric appliances and the like, and particularly to a packaging structure of a detection element section and an outer case.

[0002]

2. Description of the Related Art A conventional semiconductor pressure sensor will be described below with reference to FIG. FIG. 3 is a diagram showing the structure of a conventional pressure sensor that employs a capacitance method as pressure detection. In FIG. 3, the detection element unit 10 is bonded onto the lower outer case 7 with an adhesive 9. The detection element unit 10 is composed of a silicon substrate 1 having a diaphragm 4 that is deformed by the pressure to be measured and an insulating substrate 2,
The silicon substrate 1 and the insulating substrate 2 are formed in a state of being joined by means such as electrostatic joining.

Here, the insulating substrate 2 is provided with an electrode portion 3 which is one of the electrodes of the air condenser portion and has a through hole for detecting the gauge pressure. The diaphragm 4 of the silicon substrate 1 is bent by being subjected to a pressure difference (P = P ₁ −P ₂ ), so that the gap between the electrode portion 3 and the diaphragm 4 changes, and the gap between the silicon substrate 1 and the electrode portion 3 is changed. The capacitance value of the formed air capacitor changes. There is a certain correlation between the pressure and the gap, and the two lead terminals 8 are electrically connected to the diaphragm 4 and the electrode portion 3 and are detected by the detection element portion 10 via the lead terminals 8. The amount of change in the electrostatic capacitance value of the air condenser formed between the silicon substrate 1 and the electrode portion 3 is sent to a capacitance-frequency conversion circuit (not shown) in the subsequent stage. The change in the capacitance value is measured by the capacitance-frequency conversion circuit (not shown), converted into a signal corresponding to the change in the capacitance value and output, and the pressure desired to be obtained from the output Can be detected.

[0004]

However, in the above-mentioned conventional pressure detection method, the space area to which the measured pressure P ₁ is applied is the upper outer case 6 and the detection element section 1.
0 is applied to the entire space region surrounded by the lower outer case 7, but is actually applied to the detection element unit 10 if there is a leak at the joint interface between the upper outer case 6 and the lower outer case 7. There is a problem in that the pressure drops a few percent below P ₁ , resulting in a measurement error. In order to solve this problem, an auxiliary insulating substrate (not shown) having a through hole on the silicon substrate 1 is bonded on the silicon substrate 1 by a bonding means such as electrostatic bonding, and the pressure on the upper outer case 6 is further increased. P
A method has been proposed in which the inner wall of the inlet for introducing ₁ is joined with an adhesive or the like. In this way,
The detection accuracy is maintained by limiting the path of the pressure P ₁ . However, this method causes the cost of the detection element section to increase because the detection element section has a three-layer structure.
In addition, the step of adhering the auxiliary insulating substrate and the upper outer case 6 takes a very long time, and there is a problem that the cost becomes high as a whole.

An object of the present invention is to provide a packaging structure for a semiconductor pressure sensor, which can solve the above-mentioned problems and prevent deterioration of measurement accuracy due to pressure leakage from an outer case.

[0006]

According to the present invention, a detection element portion formed by joining a silicon substrate having a diaphragm that is deformed by a pressure to be measured and an insulating substrate having an electrode portion, and a pressure inflow through hole. In a semiconductor pressure sensor including an upper outer case and a lower outer case, the gap between the silicon substrate and the upper outer case is further sealed, and the pressure from the pressure inflow through hole is applied to the diaphragm. There is provided a packaging structure for a semiconductor pressure sensor, characterized in that it has an airtight seal portion having a pressure delivery through hole for sending to a semiconductor pressure sensor.

Further, according to the present invention, the diaphragm is formed by etching the central portion of the silicon substrate from the upper and lower surfaces thereof, and the airtight seal portion is a convex portion having a shape corresponding to the concave portion formed by the etching. A packaging structure for a semiconductor pressure sensor is provided, which comprises: a flange portion and a flange portion, and the flange portion is closely bonded to a region of the silicon substrate excluding the recessed region and a lower surface of the upper outer case. .

Further, according to the present invention, there can be obtained a packaging structure for a semiconductor pressure sensor, characterized in that the thickness dimension of the convex portion is smaller than the depth dimension of the concave portion.

Furthermore, according to the present invention, the upper outer case and the lower outer case are joined by an adhesive,
And a packaging method for a semiconductor pressure sensor, characterized in that any one of a method by ultrasonic welding, a method by mechanical caulking and a method by screwing is used.

[0010]

The airtight seal portion is integrally formed of silicon resin or the like, and is formed of a convex portion and a collar portion corresponding to the etching region (recess) of the silicon substrate, and a pressure delivery through hole is formed in the central portion thereof. It is provided. The collar portion realizes the airtight seal portion, and the convex portion corresponding to the etching region realizes a stopper function of the diaphragm of the silicon substrate.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a view showing a packaging structure of a semiconductor pressure sensor according to the present invention. FIG. 2 is an exploded perspective view showing the structures of the detection element section and the airtight seal section.
The pressure sensor shown in FIG. 1 is the same in structure as the conventional pressure sensor shown in FIG. 3 except that an airtight seal portion 5 is newly provided. Therefore, here, the same reference numerals as those used in FIG. 3 are used in the portions common to FIG. In FIG. 1, the detection element portion 10 is formed by electrostatically bonding a silicon substrate 1 and an insulating substrate 2 having an electrode portion 3 on one surface, and an inner wall of the lower outer case 7 is formed by an adhesive 9. Is joined to. An airtight seal portion 5 is provided between the silicon substrate 1 and the upper outer case 6. Airtight seal part 5
Has a pressure delivery through hole 13 for sealing the gap between the silicon substrate 1 and the upper outer case 6 and sending the pressure from the pressure inflow through hole 11 to the diaphragm 4. The diaphragm 4 is formed by etching the central portion of the silicon substrate 1 from the upper and lower surfaces thereof, and the airtight seal portion 5 has a convex portion 12 (see FIG. 2) having a shape corresponding to the concave portion 15 (see FIG. 2) formed by the etching. ) And the collar portion 14. Here, the inner diameter of the pressure delivery through hole 13 is almost the same as that of the pressure inflow through hole 11, and when the airtight seal portion 5 is installed in the gap between the silicon substrate 1 and the upper outer case 6, the pressure delivery through hole is formed. 13 central axis and pressure inflow through hole 11
It is necessary to provide the pressure delivery through hole 13 in the airtight seal portion 5 so that the central axis of the pressure transmission through hole 13 is aligned. The flange portion 14 is closely bonded to the region of the silicon substrate 1 excluding the recessed region and the lower surface of the upper outer case 6. The collar portion 14 is the upper outer case 6
The lower outer case 7 and the lower outer case 7 are joined together, and at the same time, they are crimped in the thickness direction. Therefore, the silicon substrate 1 and the upper outer case 6 are hermetically sealed so that the pressure flowing from the pressure inflow through hole 11 does not leak from the joint surface between the upper outer case 6 and the lower outer case 7.

Here, the dimension t _{1 in} the thickness direction of the convex portion 12 having a shape corresponding to the concave portion 15 (etching region) is the concave portion 1
Than the depth dimension L ₁ of 5, slightly (approximately 200~500μm
The difference is). That is, with such a structure, the upper outer case 6 and the lower outer case 7 are
Since the upper surface of the diaphragm 4 and the lower surface of the convex portion 12 are spaced by a predetermined distance even after joining and, the convex portion 12 also functions as a stopper function of the diaphragm 4.

It should be noted that the present invention is not limited to the above-mentioned embodiments, and various changes and modifications can be made without departing from the gist of the present invention. For example, a silicon substrate having a diaphragm is in a state of being etched from the upper and lower surfaces thereof in this embodiment, and has a shape having recesses in the upper and lower portions of the central portion of the silicon substrate. There is no limitation, and even if the silicon substrate has a shape in which a recess is formed by etching only the lower surface of the silicon substrate, that is, the surface on the electrode side, and the diaphragm is formed on the entire upper surface, the upper surface and the upper outer case above it The same effect as described above can be obtained by providing an airtight seal portion that airtightly seals the gap between and. In this case, the shape of the airtight seal portion is different from that of the above-mentioned embodiment, and is a flange-like shape having a pressure delivery through hole at the center.

[0014]

As described above, according to the present invention, the deterioration of the measurement accuracy due to the pressure leakage from the outer case, which has been a problem in the related art, is prevented, and the airtight seal portion is used to hermetically seal the outer case. Even if there is a pressure leak, it is not affected at all.

Further, the airtight seal portion can also function as a diaphragm stopper. That is, it is not necessary to use a three-layer structure for the detection element unit as in the conventional case, and the structure can be simplified.

[Brief description of drawings]

FIG. 1 is a diagram showing a packaging structure of a semiconductor pressure sensor according to the present invention.

FIG. 2 is an exploded perspective view showing the structures of a detection element section and an airtight seal section.

FIG. 3 is a view showing a packaging structure of a conventional semiconductor pressure sensor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Silicon substrate 2 Insulating substrate 3 Electrode part 4 Diaphragm 5 Airtight seal part 6 Upper outer case 7 Lower outer case 8 Lead terminal 9 Adhesive 10 Detection element part 11 Pressure inflow through hole 12 Convex part 13 Pressure sending through hole 14 Collar part 15 recess

Claims (4)

[Claims] 1. A detection element portion formed by joining a silicon substrate having a diaphragm that is deformed by the pressure to be measured and an insulating substrate having an electrode portion, an upper outer case and a lower outer case having pressure inflow through holes. And a pressure sending through hole for sending a pressure from the pressure inflow through hole to the diaphragm. A packaging structure for a semiconductor pressure sensor comprising an airtight seal portion. 2. The semiconductor pressure sensor packaging structure according to claim 1, wherein the diaphragm is formed by etching a central portion of the silicon substrate from upper and lower surfaces thereof, and the airtight seal portion is formed by the etching. A semiconductor pressure, comprising: a convex portion having a shape corresponding to a concave portion; and a flange portion, the flange portion being closely bonded to a region of the silicon substrate excluding the concave region and a lower surface of the upper outer case. Sensor packaging structure. 3. The packaging structure for a semiconductor pressure sensor according to claim 2, wherein a thickness dimension of the convex portion is smaller than a depth dimension of the concave portion. 4. The packaging structure for a semiconductor pressure sensor according to claim 1, wherein the upper outer case and the lower outer case are joined by an adhesive method or ultrasonic welding. A packaging structure for a semiconductor pressure sensor, characterized in that any one of a method, a mechanical crimping method, and a screwing method is used.