JPH01431A - semiconductor pressure sensor - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a semiconductor pressure sensor, and particularly to a type of semiconductor pressure sensor that is assembled onto a printed circuit board such as a printed board.

[Conventional technology]

Figure 2 shows a cross-sectional view of a semiconductor pressure sensor with a conventional structure.
In the figure, an IC chip 2 is bonded to a ceramic substrate 1, and the ceramic substrate 1 is attached to a substrate 14 such as a printed board using a clip 7a. And that board 1
A package-type pressure sensor 20 hermetically sealed by a can package 15 is connected to 4 by a pin 13a. In this state, it is stored in a case 10a, a filler 8 is added (hereinafter referred to as a blank space), and the case is covered with a lid 10b. The can package type pressure sensor 20 houses a semiconductor pressure sensor chip 3 mounted on a pedestal 5a, and its electrical signal is taken out from the pin 13a via the wire 9. Further, a through hole is formed in the pedestal 5a in order to transmit the pressure medium entering the pressure introduction pipe 17 from the pressure introduction port 16 formed in the case 10a to the semiconductor pressure sensor chip 3. Further, in the figure, 11 is a vacuum chamber, 12a is an O-ring for increasing the airtightness between the case 10a and the pressure introduction pipe 17, and 13 is a pin for taking out the electric signal obtained by the semiconductor pressure sensor to the outside.

[Problem that the invention seeks to solve]

However, in the above-mentioned conventional configuration, the filler 8 that protects the IC chip 2 from water, oil, etc. does not affect the semiconductor pressure sensor chip 3 or is not affected by other external conditions. It is hermetically sealed with a can package 15 to detect pressure with high accuracy, and the pressure medium to be measured is placed in a pressure introduction boat 16. The pressure is introduced through the pressure introduction pipe 17 and the pedestal 5a, which requires a large number of parts, making the configuration complicated.

Also, can package type pressure sensor 20. The IC chip 2 and the like are arranged in a flat manner, and when the semiconductor pressure sensor is attached to a printed board, a problem arises in that it occupies a large area and is not suitable for downsizing the device.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a semiconductor pressure sensor which has a relatively simple structure and is excellent in workability and mountability on a printed circuit board.

[Means for solving problems]

In order to achieve the above object, the semiconductor pressure sensor of the present invention includes: a substrate on which a semiconductor pressure sensor chip and another semiconductor chip are mounted; a case that houses the substrate; and a space between the case and the substrate. a shielding member that is airtightly interposed between the semiconductor pressure sensor chip and the other semiconductor chip, the semiconductor pressure sensor chip side being separated by the shielding member; The case is characterized by having a through hole in the case.

[Effect]

According to the above means, it is possible to introduce the pressure medium to the semiconductor pressure sensor chip without using any can package, and at this time, it is not affected by the filler etc. due to the shielding member.

〔Example〕

The present invention will be explained below with reference to embodiments shown in the drawings. 1st
Embodiment 1 of the present invention is shown in the figures, and FIG.
) shows a sectional view taken along line B-B. At Zusha, numeral 3 is a semiconductor pressure sensor chip (hereinafter referred to as "sensor chip") in which a strain gauge is formed in silicon and a diaphragm is provided in the center. For example, by anodically bonding it to a pedestal 5 made of Pyrex glass or the like, a vacuum chamber 11 serving as a reference pressure chamber for the sensor chip 3 is formed. The pedestal 5 is a ceramic substrate 1 on which a thick film resistance circuit is printed using silicone rubber or the like.
The ceramic substrate 1 and the sensor chip 3 are electrically connected by bonding the wires 9 to the ceramic substrate 1 and the sensor chip 3 . In addition to the pedestal 5, an IC chip 2 having a function of amplifying a signal from the sensor chip 3 and the like are bonded to the ceramic substrate 1 by solder. In addition to this ceramic substrate, the substrate referred to in the present invention may be a glass-epoxy substrate, a hollow substrate, a phenol substrate, or the like.

Then, a sealing member 4, which is a shielding member made of a material such as nitrile rubber, which has elasticity and maintains sealing properties when compressed, is arranged to surround the sensor chip 3 and fixed to the ceramic substrate 1, and in that state. Bag-shaped case 10
Push the ceramic substrate 1 inside. Here, Patsukin 4
When the ceramic substrate 1 is pushed in, the case 1 faces the ceramic substrate 1 and the sensor chip 3.
0 so that it is compressed and interposed airtightly,
Its thickness is properly adjusted. Further, the case 10 facing the ceramic substrate 1 has a through hole 6 which is a pressure introduction port.
is opened. The through hole 6 is formed in the case 10 at a position relatively close to the sensor chip 3 in order to reduce the adverse effects of foreign matter entering from the outside through the through hole 6.
．． It is best to place the wire 9 etc. in a position where the case 10 is not placed.
A guide 10a is formed in which a portion of the guide 10a is thickened in order to easily push the ceramic substrate 1 into the guide 10a.

Next, the clip 7 is soldered to the ceramic substrate 1 to make an electrical connection. Then, the circuit on the ceramic substrate 1, I
In order to protect the C-chip 2 and the like from water, oil, etc., a filler 8 such as epoxy resin or silicone rubber is placed in the case 10, packaged to form a semiconductor pressure sensor, and then clipped to a printed board (not shown) or the like. Connect by 7. In the case of this embodiment, the adhesive strength between the case 10 and the filler 8 is increased, and the mechanical strength of the semiconductor pressure sensor is improved.
In order to prevent moisture from entering, after the case 10 is molded, the surface inside the case 10 is tumbled using glass powder, walnut powder, etc. to form irregularities.

This treatment is particularly advantageous when a transparent material is used as the case material (hereinafter referred to as a margin) because it does not impair the appearance compared to forming irregularities on the surface by sandblasting etching or the like.

Therefore, according to the above configuration, by simply pushing the ceramic substrate 1 into the case 10 using the packing 4, the packing 4 can be crushed to ensure airtightness, and the filling material 8 can be prevented from flowing in. Therefore, workability is improved and the structure is relatively compact. Furthermore, since this embodiment has a three-dimensional structure in which the sensor chips 3 and the like are arranged in the vertical direction, it does not occupy much area when assembled to a printed board or the like, and is therefore excellent in mountability.

FIG. 3 shows a second embodiment of the present invention, and FIG. 3(a) shows a cross-sectional view from the front, and FIG. 3(b) shows a cross-sectional view taken along the line C--C. In the figure, the difference from the first embodiment is that the packing 4
Instead, a frame 18 with a 6-shaped cross section is used, and an O-ring 1 is inserted into the groove of the frame 18 to improve airtightness.
2 is included. Furthermore, the square of the frame 18 is the ceramic substrate 1.
It has a hook shape 18a in order to connect it to the base. It goes without saying that the same effects as in the first embodiment can be obtained in this embodiment as well.

The third embodiment of the present invention is shown in Figure 1, the front sectional view is shown in (a), and the DD line sectional view is shown in (b) and (c). The differences from the first embodiment are as follows:
The height of the packing 4a is set to be slightly lower than the distance between the ceramic substrate l and the case 10, as shown in FIG.
The distance between the case 10 and the case 10 is, for example, 0.3 wa or less. Moreover, the ceramic substrate 1 is inserted into the case 10 by gravity. Then, in this state, from the opening side of the bag-shaped case 10,
A predetermined amount of the filler 8a with low viscosity is injected into the gap between the packing 4a and the case 10. In the case of this example, the viscosity of the filler 8a is 20 poise or less. here,
The injected filler 8a is packed into the packing 4a by capillary action.
The gap between the packing 4a and the case 10 is moved as shown by the arrow in FIG.
There is a good airtight interposition between the two.

In the case of this embodiment, the shielding member referred to in the present invention is composed of a packing 4a and a filler 8a.

Further, since the injection amount of the filler 8a is adjusted to a predetermined amount, there is no problem that the filler 8a stays in the gap between the packing 4a and the filler 8a and enters the space 21 and comes into contact with the sensor chip 3. After that, the filler 8a is cured, and subsequently the filler 8b is injected and cured, and packaging is performed.

Therefore, according to the third embodiment, in addition to obtaining the same effects as the first embodiment, the ceramic substrate 1 is placed in the case 10.
When inserting it into the interior, it is inserted by gravity without any force, so it is more workable, and stress is not applied to the case 10, ceramic substrate 1, etc. due to the compressive reaction force of the packing 4a. There is an effect. In the third embodiment, the height of the packing 4a is such that stress due to the compressive reaction force of the packing 4a is not applied to the case 10, the ceramic substrate 1, etc., and a capillary phenomenon occurs in the filler 8a. For example, the material of the filler 8b may be the same as that of the filler 8a, or it may have a relatively viscosity. It may also be made of other expensive materials. or,
The material of the case 10 is PBT (polybutylene terephthalate), PPS (polyphenylene sulfide)
.

PES (polyether sulfone), PC (polycarbonate), etc. are applicable, but PES.

If a transparent material such as PC is used, the injection state of the fillers 8a and 8b inside the case 10 can be confirmed from outside the case 10. In that case, the effect is enhanced by coloring the fillers 8a and 8b with, for example, a black pigment.

Next, a fourth embodiment of a structure to which the present invention can be favorably applied as a negative pressure sensor will be described with reference to FIGS. 5 and 6.

FIG. 5(a) is a side sectional view of the fourth embodiment, and FIG. 5(b) is a side sectional view of the fourth embodiment.
is its front view, and (C) is its top view. In the figure, the differences from the first to third embodiments are as follows:
The frame 18 in the embodiment is a frame 19 having a concave cross section, and the frame 19 and the ceramic substrate 1 are bonded together with an adhesive. In addition, there is a pressure introduction port protruding from the case 10).
16a, and negative pressure is detected via this pressure introduction boat 16a. Further, a fixing member 22 is formed on the side wall of the case 10 so that a computer or the like can be easily mounted in a case that stores the same.
2 is provided with a through hole 22a.

FIG. 6 is a diagram showing a state in which the semiconductor pressure sensor of the fourth embodiment is mounted in a case, and FIG. 6(a) is a top view thereof;
Figure (b) is its side view. As shown in the figure, the pressure introduction boat 16a is inserted into the hole 24b made in the case 24, and the clip 7 is inserted into the printed board 25 and soldered. Then, the fixing pin 23 is inserted into the case 24 so that the hole 24a drilled in the case 24 and the through hole 22a are aligned with each other, and fixed. By fixing the semiconductor pressure sensor in the above-described manner, the load placed on the clip 7 can be reduced. Further, negative pressure can be introduced by installing, for example, a conduit in the pressure introduction boat 16a that protrudes outside the case 24.

Further, when used as a negative pressure sensor, in order to further improve airtightness in the space surrounded by the frame 19, the inner surface of the case 10 is shown in an enlarged view of section E in FIG. Same figure (
As shown in d), it is desirable to perform the above-mentioned tumble processing to form unevenness. Furthermore, in order to protect the sensor chip 3 from moisture, gasoline, and other contaminants, a gel-like filler 26 such as silicone gel may be injected into the space surrounded by the frame 19. In this case, the injection is case 10
Since this can be done before inserting the sensor chip 3 etc. into the interior, it can be done more easily than in the past. moreover,
As the substrate on which the sensor chip 3 is mounted, as shown in FIG. 5(a), Pyrex glass or the like used as the pedestal in the first to third embodiments may be used as the substrate 5a. Note that the substrate 5a may be a ceramic substrate as in the first to third embodiments, and the pedestal may also have a shape similar to those examples, and the filler 26. The concept of the substrate 5a and the frame 19 can also be applied to an atmospheric pressure sensor.

It should be noted that the present invention is not limited to the first to fourth embodiments described above, and can be modified in various ways without departing from the spirit thereof.
For example, as shown in the sectional view of the fifth embodiment in FIG. 7, it may be arranged in a plane. Further, in the above embodiment, a packing that surrounds the sensor chip 3 is used as the shielding member according to the present invention, but as shown in the front cross-sectional view of another embodiment in FIG. 8(a), Φ). , using a packing 4b formed to separate the sensor chip 3 and the IC chip 2, a filler such as epoxy resin or silicone rubber can be applied to the IC.
You can also inject only into the tip 2 side (also, if the bent 2
The sensor chip 3 may be surrounded by the case 10 using a packing 4C consisting of sides. Further, it goes without saying that the front shape of the shielding member does not have to be square, but may be circular or the like.

Furthermore, the shape of the shielding member may be box-shaped, in other words, the shape of a bottomed hole with a concave portion, and the pressure introduction port may be formed by injecting the filler and drilling the hole with a needle-like member after curing. good.

〔Effect of the invention〕

As described above, according to the semiconductor pressure sensor of the present invention,
The sensor chip can be protected from fillers by simply bonding the shielding member to the substrate and pushing it into the case, improving workability and making the structure relatively simple.

Moreover, the three-dimensional structure has the advantageous effect that it is possible to provide a semiconductor pressure sensor that is easy to mount on a printed board.

[Brief explanation of the drawing]

FIGS. 1(a), (6), and (C) are cross-sectional views of the first embodiment of the present invention, FIG. 2 is a cross-sectional view of the conventional structure, and FIGS. 3(a),
(b) is a sectional view of the second embodiment of the present invention, and FIG.
),(B). (C) is a sectional view of the third embodiment of the present invention, FIG. 5(a)
. 6), (C), and (d) are cross-sectional views of the fourth embodiment of the present invention, and FIGS. 6(a) and (b) represent the mounting state of the fourth embodiment of the present invention in a case. 7 are sectional views of a fifth embodiment of the present invention, and FIGS. 8(a) and 8(b) are front sectional views of other embodiments of the present invention. 1... Ceramic substrate, 2... IC chip, 3...
・Semiconductor pressure sensor chip, 4.4a, 4b, 4c・
...Passkin, 5...Pedestal, 6...Through hole, 8.8
a. 8b...Filling agent, 10...Case, 12...0
Ring. 16...Pressure introduction boat, 18.19...Frame.

Claims (7)

[Claims] (1) A substrate on which a semiconductor pressure sensor chip and other semiconductor chips are mounted, a case housing the substrate, and a case interposed between the case and the substrate with good airtightness, and a substrate on which the semiconductor pressure sensor chip and other semiconductor chips are mounted; A semiconductor pressure sensor comprising: a shielding member formed to separate the semiconductor chip from the other semiconductor chip, and having a through hole in the case on the side of the semiconductor pressure sensor chip separated by the shielding member. sensor. (2) The semiconductor pressure sensor according to claim 1, wherein the shielding member has elastic force. (3) The shielding member includes a first member formed with a gap between the case and the substrate, and a second member interposed in the gap with good airtightness. A semiconductor pressure sensor according to scope 1. (4) The semiconductor pressure sensor according to any one of claims 1 to 3, wherein the shielding member is formed to surround the semiconductor pressure sensor chip. (5) The semiconductor pressure sensor according to any one of claims 1 to 4, wherein the inner surface of the case has fine irregularities. (6) The semiconductor pressure sensor according to any one of claims 1 to 5, wherein the case is made of a transparent material. (7) The semiconductor pressure sensor according to any one of claims 1 to 6, wherein the through hole is formed at a position where the semiconductor pressure sensor chip is not located.