JP2001066320A - Semiconductor accelerometer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a semiconductor accelerometer whose sensitivity can be enhanced without making the accelerometer large. SOLUTION: This semiconductor accelerometer 10 is constituted of an accelerometer chip 11 which is formed in a shape wherein a chip body 110 which is formed in a quadrangular shape and which has a rectangular hole bored in the central part is provided, a pair of cantilevers 111 which are formed so as to be extended to the right side in the right and left directions from the central part in the left of the hole in the chip body 110 are provided, and a mass part 112 which is formed integrally on tip sides of the respective cantilevers 111 so as to be supported is provided. The semiconductor accelerometer is constituted of an upper glass cap 12 which is bonded to the surface of the accelerometer chip 11. The semiconductor accelerometer is constituted of a lower glass cap 13 which is bonded to the rear surface of the accelerometer chip 11. The upper glass cap 11 is bonded via metal thin films formed on both end sides along the right and left directions on the surface of the accelerometer chip 11. The right and left directions on the surface of the accelerometer chip 11 are set to an open state.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor acceleration sensor for detecting an acceleration by an electric signal proportional to the acceleration.

[0002]

FIG. 7 is a sectional view showing an example of a conventional semiconductor acceleration sensor, FIG. 8 is a top view of the acceleration sensor chip shown in FIG. 7, and FIG. 9 is a sectional view taken along line CC 'shown in FIG. is there.

A semiconductor acceleration sensor 90 shown in FIG. 7 belongs to a so-called cantilever type, and has an acceleration sensor chip 91 formed of a silicon substrate and an upper glass cap 92 fixed on the upper surface of the acceleration sensor chip 91 by anodic bonding. And a lower glass cap 93 fixed on the lower surface of the acceleration sensor chip 91 by anodic bonding. W is a wire formed by wire bonding.

As shown in FIG. 8, the acceleration sensor chip 91 has a chip body 910 formed in a square shape and having a square hole 910a drilled in the center, and a hole 910a in the chip body 910. Each of the cantilevers 911 is formed in a shape having a pair of cantilevers 911 extending from the left to the right and a mass portion 912 integrally formed on the distal end side of each of the cantilevers 911 and supported inside one side. Each cantilever 911 has a mass 91
A gauge resistor (piezo gauge resistor) 911a that takes out, as an output, a voltage proportional to the acceleration of the force (F) received by α (α = F / m; m is the weight of the mass portion 912) is diffused to 2
Individually formed. Here, when the mass portion 912 moves under the force, each cantilever 911 bends and each gauge resistor 9
Since the value of 11a changes, the acceleration of the force received by the mass section 912 can be detected by looking at the value of each gauge resistor 911a.

Further, a diaphragm is formed on the lower surface side of the gauge resistor 911a (see FIG. 7). Further, the acceleration sensor chip 91 includes a wire bonding pad 110b, an aluminum wiring 110c, and a contact portion 110d.
And a wiring 210e of a P + diffusion layer.

The upper glass cap 92 is made of heat-resistant glass having a coefficient of thermal expansion substantially equal to that of the silicon substrate, and is formed in a plate-shaped concave portion 9 formed by etching, sandblasting, or the like at the center of the lower surface facing the acceleration sensor chip 91.
2a (see FIG. 7). The lower glass cap 93 is made of heat-resistant glass having a thermal expansion coefficient substantially equal to that of the silicon substrate, and is formed in a plate-like shape having a concave portion 93a formed by etching, sandblasting, or the like at the center of the upper surface facing the acceleration sensor chip 91. (See FIG. 7). Such upper glass cap 92 and lower glass cap 9
3 is fixed to the acceleration sensor chip 91 to form an air gap, air damping is performed under atmospheric pressure, and each cantilever 911 and mass section 912 as a sensing unit of the acceleration sensor chip 91 are sealed. Accordingly, excessive movement of the sensing unit is suppressed even when receiving excessive acceleration, so that the semiconductor acceleration sensor 90 can be prevented from being broken.

[0007] In the bottom surfaces of the concave portions 92a and 93a facing the acceleration sensor chip 91 in the upper glass cap 92 and the lower glass cap 93, a projection-like stopper for restricting the movement of the mass portion 912 when receiving acceleration. 12
b and 13b are formed two each. Here, each stopper is provided in order to prevent the cantilever 911 from being damaged by restricting the movement of the mass portion 912 when the mass portion 912 is subjected to excessive acceleration and to prevent the cantilever 911 from being damaged. The shape is set so that the mass section 912 has an attenuation characteristic that optimizes the frequency characteristic of the semiconductor acceleration sensor 90 itself using the air damping effect.

On the joining surface of the acceleration sensor chip 91 to which the upper glass cap 92 and the lower glass cap 93 are joined, an aluminum thin film having a thickness of about 1 to 2 μm (in FIG. Only an aluminum thin film 910f for the glass cap 92 is shown). More specifically, as shown in FIG. 9, an oxide film 910g is formed on the lower surface side of one side of the aluminum thin film 910f on the wire bonding pad 110b side, but the wiring 210e of the P + diffusion layer is formed of the oxide film 910g. The oxide film 910g is formed on the lower surface side and the upper surface side of the oxide film 910g is thinned.
The aluminum thin film 910f on the upper surface side of 10 g is depressed, and a cavity (gap) Cav is formed in this portion at an interval of about 1000 to 2000 °, and ventilation is performed in this cavity Cav.

A semiconductor acceleration sensor of this type is disclosed, for example, in Japanese Patent Application Laid-Open No. 7-159432.

[0010]

However, in the case of a semiconductor acceleration sensor in which the mass portion has a damping characteristic by utilizing the air damping effect as described above, when the sensitivity is improved, the size of the semiconductor acceleration sensor becomes large. There were challenges. Here, the sensitivity of the semiconductor acceleration sensor is given by the following equation.

[0011]

(Equation 1)

As can be seen from this equation, it is necessary to increase the weight of the mass portion or to increase the distance of the center of gravity in order to improve the sensitivity. In either case, it is necessary to increase the size of the mass portion. Occurs, and the size of the joint area between the acceleration sensor chip and the upper glass cap via the aluminum thin film affects the size of the acceleration sensor chip. As a result, the size of the semiconductor acceleration sensor increases.

The present invention has been made in view of the above circumstances, and has as its object to provide a semiconductor acceleration sensor capable of improving sensitivity without increasing the size.

[0014]

According to a first aspect of the present invention, there is provided a semiconductor acceleration sensor which is formed integrally with an elastic cantilever extending in one direction and a tip end of the cantilever. Sensor chip having a weight part supported and supported, a concave first cap bonded on one surface of the acceleration sensor chip, and a concave cap bonded on another surface of the acceleration sensor chip Second
A cap which is formed on the cantilever as a sensing element for taking out a signal proportional to the acceleration received by the weight portion as an output, wherein the gauge resistance is the acceleration sensor chip facing the first cap. And the first and second surfaces
A projection-like stopper for restricting the movement of the weight portion when receiving acceleration is formed in a concave bottom surface of the cap that faces the acceleration sensor chip, and the first cap is formed of the acceleration sensor chip. The bonding is performed via metal thin films formed on both ends of the one surface along the one direction, and the one direction on the one surface is opened.

In this structure, the metal thin film for joining the first cap is formed on both ends of the one surface of the acceleration sensor chip along one direction, so that the area of the metal thin film to be formed on the first cap is formed. Becomes smaller. And since the part obtained by reducing the area of the metal thin film can be distributed at least to the weight part, the weight part can be made large. As a result, the weight of the weight increases, so that the sensitivity of the semiconductor acceleration sensor improves. Also, in this case, the weight part expands in one direction,
Since the center of gravity of the weight part moves away from the cantilever, the distance of the center of gravity increases, and the force applied to the weight part is amplified by the principle of leverage, so that the sensitivity of the semiconductor acceleration sensor is further improved. Therefore, by adopting the above structure, the sensitivity can be improved without increasing the size.

According to a second aspect of the present invention, there is provided a semiconductor acceleration sensor having an elastic cantilever extending in one direction and a weight integrally formed and supported on a tip side of the cantilever. A chip, a concave first cap joined to one surface of the acceleration sensor chip, and a concave second cap joined to the other surface of the acceleration sensor chip;
A gauge resistor is formed as a sensing element that takes out a signal proportional to the acceleration received by the weight portion as an output, and the gauge resistor is located on one surface side of the acceleration sensor chip facing the first cap, First
A protrusion-shaped stopper for restricting the movement of the weight portion when receiving acceleration is formed in a concave bottom surface of the second cap facing the acceleration sensor chip, and the first cap is provided with the acceleration sensor chip. The sensor chip is joined via metal thin films formed on both ends along a direction orthogonal to the one direction on one surface of the sensor chip, and the orthogonal direction on the one surface is opened.

In this structure, the metal thin film for joining the first cap is formed on both ends of the one surface of the acceleration sensor chip along a direction orthogonal to the one direction. The area of the metal thin film is reduced.
Then, a portion obtained by reducing the area of the metal thin film can be distributed to the weight portion, so that the weight portion can be made large. As a result,
Since the weight of the weight increases, the sensitivity of the semiconductor acceleration sensor improves. Therefore, by adopting the above structure, the sensitivity can be improved without increasing the size.

In the semiconductor acceleration sensor according to the first aspect, a wire bonding pad is provided on one surface of the acceleration sensor chip at one of both ends orthogonal to the one direction, and the first cap is provided. May be formed in a shape extending toward the wire bonding pad on one surface of the acceleration sensor chip (claim 3). In this structure, since the semiconductor junction coating range can be applied to the wire bonding pad side, it is possible to reduce stress due to vibration and impact on the wire connected to the wire bonding pad.

[0019]

1 is a sectional view showing a semiconductor acceleration sensor according to a first embodiment of the present invention, FIG. 2 is a top view of the acceleration sensor chip shown in FIG. 1, and FIG. 3 is an upper glass shown in FIG. FIG. 3 is a perspective view of the cap.
An embodiment will be described. However, FIG. 1 is AA ′ of FIG.
It is sectional drawing in a line.

A semiconductor acceleration sensor 10 shown in FIG. 1 has an acceleration sensor chip 11 formed of a silicon substrate.
And an upper glass cap 12 (first cap) joined on the upper surface of the acceleration sensor chip 11, and a lower glass cap 1 joined on the lower surface of the acceleration sensor chip 11.
3 (second cap). Note that W
Is a wire by wire bonding.

As shown in FIG. 2, the acceleration sensor chip 11 is formed in a square shape (rectangular shape in the figure) and has a chip body 110 having a rectangular hole 110a drilled at the center thereof. Hole 110 in body 110
a, a pair of resilient cantilevers 111 extending to the right in one direction (left-right direction in the figure) from the left side of a, and formed integrally at the tip side of each of these cantilevers 111 and supported inside one side. And has a mass portion 112 (weight portion). However, the rectangular hole 1
10a is a slit-shaped hole shown in FIG. 2 due to the presence of the pair of cantilevers 111 and the mass portion 112 therein. Therefore, when manufacturing the acceleration sensor chip 11, the slit-shaped hole is formed. Needless to say, it should be done.

In the example of FIG. 2, each cantilever 11
In FIG. 1, two gauge resistors 111a are formed as sensing elements for taking out a voltage proportional to the acceleration of the force received by the mass portion 112 as an output. On the other hand, on the left end side on the upper surface of the chip body 110, five wire bonding pads 110b are arranged at equal intervals along the vertical direction. Each wire bonding pad 110b is connected to a contact portion 110d via an aluminum wiring 110c.
d is electrically connected to the gauge resistor 111a via the wiring 110e of the P + diffusion layer of the main body. Also, of the plurality of wirings 110e of the P + diffusion layer, the contact portion 110 with the lowermost wire bonding pad 110b is formed.
The wiring 110e of the P + diffusion layer of d is a cantilever 111
As crack detection wiring for detecting cracks in
The wire is routed through the lower cantilever 111 and the upper cantilever 111, and is connected to a contact portion 110d for the uppermost wire bonding pad 110b.

Further, on the upper surface of the chip body 110, the bonding surface with the upper glass cap 12, that is, on both ends (upper and lower ends in FIG. 2) along the above-mentioned one direction, the upper glass cap 12 is bonded. Aluminum thin film 110f
Are formed. Further, a frame-shaped aluminum thin film (not shown) having four sides is formed on the lower surface of the chip body 110 on the bonding surface with the lower glass cap 13 for bonding the lower glass cap 13 as in the related art. .

The upper glass cap 12 is made of a heat-resistant glass having a thermal expansion coefficient substantially equal to that of the silicon substrate, and is formed in a bridge shape, that is, a plate shape as shown in FIG. It has a concave portion 12a having a depth of several tens μm formed by both ends thereof. On the other hand, the lower glass cap 13 is made of heat-resistant glass having a coefficient of thermal expansion substantially equal to that of the silicon substrate, and is made of a plate-shaped and acceleration sensor chip 1.
A concave part 1 having a depth of several tens μm
3a. Concave portions 12a, 13a of the upper glass cap 12 and the lower glass cap 13 facing the acceleration sensor chip 11.
As shown in FIG. 1, projecting stoppers 12b for restricting the movement of the mass portion 112 when receiving acceleration,
13b are formed two each. In addition, the stopper is set at a height about several μm to about 10 μm lower than the depth of the recess, and the upper surface size is about several hundred μm.
Is set to be However, upper glass cap 1
The arrangement of the stoppers formed in the respective concave portions of the second glass cap 13 and the lower glass cap 13 is not particularly limited.

The lower glass cap 13 is connected to the acceleration sensor chip 1 via a frame-shaped aluminum thin film having four sides.
1 is fixed to the lower surface by anodic bonding. In contrast, the first
As a feature of the embodiment, the upper glass cap 12 is fixed to the upper surface of the acceleration sensor chip 11 by anodic bonding via the aluminum thin film 110f at the two sides of both end edges bent downward. The one direction is open. Hereinafter, the portion in the open state is referred to as an open portion 14.

Next, the function of the first embodiment will be described. When the metal thin film 110f for bonding the upper glass cap 12 is formed on both ends along one direction on the upper surface of the acceleration sensor chip 11, an aluminum thin film in the vertical direction which is necessary in the conventional semiconductor acceleration sensor shown in FIG. Therefore, the area of the aluminum thin film to be formed on the upper glass cap 12 is reduced. Since the vertical aluminum thin film forming portion of the conventional semiconductor acceleration sensor becomes the open portion 14 in the first embodiment, a part of the left open portion 14 can be distributed to the cantilever 111. Become
Since the partial area of the right opening 14 can be allocated to the mass portion 112, the size of the mass portion 112 can be increased in the one direction. As a result, the mass 1
Since the weight of the sensor 12 increases, the sensitivity of the semiconductor acceleration sensor 10 improves. Further, the center of gravity of the mass portion 112 moves away from the cantilever 111 to increase the center of gravity distance, and the force applied to the mass portion 112 is amplified by the leverage principle, so that the sensitivity of the semiconductor acceleration sensor 10 is further improved. Furthermore, in particular, by appropriately adjusting the depth of the concave portion 12a and the height of the stopper 12b of the upper glass cap 12,
When the mass section 112 moves up and down under acceleration, the opening section 14
A sufficient air damping effect can be obtained by eliminating or reducing the influence of the flow of air from the air.

FIG. 4 is a sectional view showing a semiconductor acceleration sensor according to a second embodiment of the present invention, and FIG. 5 is a top view of the acceleration sensor chip shown in FIG.
An embodiment will be described. However, FIG. 4 is BB ′ of FIG.
It is sectional drawing in a line.

A semiconductor acceleration sensor 20 shown in FIG. 4 has an acceleration sensor chip 21 formed of a silicon substrate.
And an upper glass cap 22 (first cap) bonded on the upper surface of the acceleration sensor chip 21 and a lower glass cap 2 bonded on the lower surface of the acceleration sensor chip 21
3 (second cap).

As shown in FIG. 5, the acceleration sensor chip 21 is formed in a square shape (rectangular shape in the figure) and has a square body 210a having a square hole 210a drilled in the center thereof. Hole 210 in body 210
a pair of resilient cantilevers 211 extending to the right in one direction (left-right direction in the figure) from the left side of a, and are integrally formed on the distal end side of each of these cantilevers 211 and are supported inside one side. And has a mass portion 212 (weight portion).

In the example of FIG. 5, each cantilever 21
In FIG. 1, two gauge resistors 211a are formed as sensing elements for extracting, as an output, a voltage proportional to the acceleration of the force received by the mass portion 212. On the other hand, on the left end side on the upper surface of the chip body 210, as in the first embodiment, five wire bonding pads 110b are arranged at equal intervals along the vertical direction.
Each wire bonding pad 110b is connected to a contact part 110d via an aluminum wiring 110c, and each contact part 110d is connected to a gauge resistor 211a via a P + diffusion layer wiring 210e having a different length from that of the first embodiment. Is electrically connected to Also, a plurality of P
Of the + diffusion layer wiring 210 e, the P + diffusion layer wiring 110 e of the contact portion 110 d for the lowermost wire bonding pad 110 b passes through the lower cantilever 211 as a crack detection wiring for detecting a crack of the cantilever 211. Upper cantilever 21
1 and is connected to a contact portion 110d for the uppermost wire bonding pad 110b.

Further, the bonding surface of the upper surface of the chip main body 210 with the upper glass cap 22, that is, both ends along the direction orthogonal to the one direction (the hole 21 on the left end side in FIG. 5).
An aluminum thin film 210f for bonding the upper glass cap 22 is formed on each of the right ends (close to 0a). In addition, a frame-shaped aluminum thin film (not shown) having four sides is formed on the lower surface of the chip main body 210 on the bonding surface with the lower glass cap 23 for bonding the lower glass cap 23.

The upper glass cap 22 is made of heat-resistant glass having a thermal expansion coefficient substantially equal to that of the silicon substrate, and is formed in a bridge shape, that is, in a plate shape as shown in FIG. Has a concave portion 22a having a depth of several tens of μm formed by both ends thereof being bent downward. The lower glass cap 23 is made of heat-resistant glass having a coefficient of thermal expansion substantially equal to that of the silicon substrate, and is formed in a plate-like shape.
A concave part 2 having a depth of several tens of μm in a central part of the upper surface facing 1
3a. Concave portions 22a, 23a of the upper glass cap 22 and the lower glass cap 23 facing the acceleration sensor chip 21.
As in the first embodiment, as shown in FIG.
Two protruding stoppers 12b and 13b are formed to regulate the movement of the mass portion 212 when receiving acceleration.

The lower glass cap 23 is connected to the acceleration sensor chip 2 via a frame-shaped aluminum thin film having four sides.
1 is fixed to the lower surface by anodic bonding. In contrast, the second
As a feature of the embodiment, the upper glass cap 22 is fixed to the upper surface of the acceleration sensor chip 21 via the aluminum thin film 210f by anodic bonding at two sides of both end edges bent downward. The direction orthogonal to the one direction is open. Hereinafter, the portion in the open state is referred to as an open portion 24.

Next, the operation of the structure characteristic of the second embodiment will be described. When the metal thin film 210f for bonding the upper glass cap 22 is formed on both ends of the upper surface of the acceleration sensor chip 21 along a direction orthogonal to the one direction, the above-described one required in the conventional semiconductor acceleration sensor shown in FIG. It is not necessary to form an aluminum thin film in any direction, and the area of the aluminum thin film to be formed on the upper glass cap 22 is reduced. The portion of the conventional semiconductor acceleration sensor in which the aluminum thin film is formed in the one direction becomes the open portion 24 in the second embodiment. Therefore, each of the partial regions of both open portions 14 is allocated to the mass portion 212. Therefore, the size of the mass portion 212 can be enlarged in a direction orthogonal to the one direction. As a result, the weight of the mass portion 212 increases, so that the sensitivity of the semiconductor acceleration sensor 20 improves. Particularly, by appropriately adjusting the depth of the concave portion 22a of the upper glass cap 22 and the height of the stopper 12b, when the mass portion 212 moves up and down under acceleration, the influence of the flow of air from the open portion 24. By eliminating or reducing the above, a sufficient air damping effect can be obtained.

FIG. 6 is a sectional view showing a semiconductor acceleration sensor according to a third embodiment of the present invention. The third embodiment will be described below with reference to FIG.

The semiconductor acceleration sensor 30 shown in FIG. 6 includes the acceleration sensor chip 11 and the lower glass cap 13 in the same manner as in the first embodiment. An upper glass cap 32 (first cap) is provided on the upper surface.

The upper glass cap 32 has an extended portion (hanging portion) in which the wire bonding pad 110b side extends toward the acceleration sensor chip 11 to form a gap of about 1 to 2 μm with the upper surface of the acceleration sensor chip 11. Part)
The upper glass cap 12 is formed in the same manner as the upper glass cap 12 of the first embodiment except that it is formed in a shape having 32c. The gap is substantially the same as the thickness of the aluminum thin film. It is desirable that the depth of the gap formed by the extending portion 32c is set to, for example, about 100 μm at the shortest.

Next, the operation of the extension 32c formed on the upper glass cap 32 will be described. Upper glass cap 3
2, the semiconductor junction coating range (hereinafter simply referred to as JCR) made of, for example, a silicone resin, is connected to a wire W such as Au or Al.
And it becomes possible to apply to the wire bonding pad 110b. By setting the viscosity and fluidity of the JCR, the osmotic pressure is applied to the gap formed by the extension portion 32c.
If the JCR is made to flow only to an appropriate depth and the JCR is solidified by heat curing or ultraviolet curing in that state, it is possible to prevent the JCR from flowing near the cantilever 111. The JCR has a property that the coating film after curing has rich rubber elasticity, and is generally used to reduce stress due to vibration or impact on the wire W connected to the wire bonding pad 110b. Also in the third embodiment, since the JCR can be applied by forming the extending portion 32c on the upper glass cap 32, the above-described effect can be obtained.

[0039]

As apparent from the above, according to the first aspect of the present invention, the elastic cantilever extending in one direction and the tip end of the cantilever are integrally formed and supported. An acceleration sensor chip having a weight portion, a concave first cap joined on one surface of the acceleration sensor chip, and a concave second cap joined on another surface of the acceleration sensor chip The cantilever is provided with a gauge resistor as a sensing element for taking out, as an output, a signal proportional to the acceleration received by the weight portion.
Positioned on one surface side of the acceleration sensor chip facing the cap, and inside the concave bottom surfaces of the first and second caps facing the acceleration sensor chip, the weight portions of the weight portions when receiving acceleration are respectively provided. A protrusion-shaped stopper for restricting movement is formed, and the first cap is joined via metal thin films formed on both ends of the one surface of the acceleration sensor chip in the one direction, and the first cap is connected to the first cap. Since the one direction on the surface is open, sensitivity can be improved without increasing the size.

According to the second aspect of the present invention, there is provided an acceleration sensor chip having an elastic cantilever extending in one direction and a weight portion integrally formed and supported on a tip side of the cantilever. A concave first cap joined to one surface of the acceleration sensor chip, and a concave second cap joined to another surface of the acceleration sensor chip, wherein the weight is attached to the cantilever. A gauge resistor is formed as a sensing element that takes out a signal proportional to the acceleration received by the unit as an output. The gauge resistor is located on one surface side of the acceleration sensor chip facing the first cap, and And protrusions for restricting the movement of the weight portion when receiving acceleration, respectively, in the concave bottom surface of the second cap facing the acceleration sensor chip. Are formed, and the first cap is joined via metal thin films formed on both end sides of the one surface of the acceleration sensor chip along a direction orthogonal to the one direction, and the first cap is formed on the one surface of the acceleration sensor chip. Since the orthogonal direction is opened, sensitivity can be improved without increasing the size.

According to a third aspect of the present invention, in the semiconductor acceleration sensor according to the first aspect, a wire bonding pad is provided on one of both ends orthogonal to the one direction on one surface of the acceleration sensor chip. Is provided, and the first cap is formed in a shape extending toward the wire bonding pad on one surface of the acceleration sensor chip, so that the first cap is caused by vibration or impact on the wire connected to the wire bonding pad. Stress can be reduced.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a semiconductor acceleration sensor according to a first embodiment of the present invention.

FIG. 2 is a top view of the acceleration sensor chip shown in FIG.

FIG. 3 is a perspective view of the upper glass cap shown in FIG.

FIG. 4 is a sectional view showing a semiconductor acceleration sensor according to a second embodiment of the present invention.

5 is a top view of the acceleration sensor chip shown in FIG.

FIG. 6 is a sectional view showing a semiconductor acceleration sensor according to a third embodiment of the present invention.

FIG. 7 is a cross-sectional view illustrating an example of a conventional semiconductor acceleration sensor.

8 is a top view of the acceleration sensor chip shown in FIG.

9 is a cross-sectional view taken along line C-C 'shown in FIG.

[Explanation of symbols]

 10, 20, 30 Semiconductor acceleration sensor 11, 21, Acceleration sensor chip 12, 22, 32 Upper glass cap 13, 23 Lower glass cap 14, 24 Opening part 110, 210 Chip body 110a, 210a Hole 110b Wire bonding pad 110c Aluminum wiring 110d Contact part 110e, 210e P + wiring of diffusion layer 110f, 210f Aluminum thin film 111, 211 Cantilever 111a, 211a Gauge resistance 112, 212 Mass part 12a, 22a Concave part 12b Stopper 32c Extension part 13a, 23a Concave part 13b Stopper

Continued on the front page (72) Inventor Takuro Ishida 1048 Kadoma Kadoma, Osaka Pref.Matsushita Electric Works, Ltd. (72) Inventor Masashi Kataoka 1048 Kadoma Kadoma, Kadoma, Osaka Pref.Matsushita Electric Works (72) Inventor Hironori Kami 1048 Kadoma Kadoma, Kadoma City, Osaka Prefecture (72) Inventor Takashi Saijo 1048 Odaka Kadoma, Kadoma City, Osaka Prefecture Inside Matsushita Electric Works Co., Ltd. (72) Inventor Makoto Saito Kadoma City, Osaka Prefecture 1048 Oaza Kadoma Matsushita Electric Works, Ltd.

Claims (3)

[Claims] 1. An acceleration sensor chip comprising: an elastic cantilever extending in one direction; and a weight portion integrally formed and supported on a tip side of the cantilever; A concave first cap joined to a surface of the acceleration sensor chip, and a concave second cap joined to another surface of the acceleration sensor chip, wherein the cantilever is proportional to an acceleration received by the weight portion. A gauge resistor is formed as a sensing element that takes out a signal as an output, and the gauge resistor is located on one surface side of the acceleration sensor chip facing the first cap, and the acceleration sensor in the first and second caps In the concave bottom surface facing the chip, a projection-like stopper that regulates the movement of the weight portion when receiving acceleration is formed, The first cap is connected via metal thin films formed on both ends of the one surface of the acceleration sensor chip along the one direction to open the one direction on the one surface. Acceleration sensor. 2. An acceleration sensor chip comprising: an elastic cantilever extending in one direction; and a weight portion integrally formed and supported on a tip side of the cantilever; A concave first cap joined to a surface of the acceleration sensor chip, and a concave second cap joined to another surface of the acceleration sensor chip, wherein the cantilever is proportional to an acceleration received by the weight portion. A gauge resistor is formed as a sensing element that takes out a signal as an output, and the gauge resistor is located on one surface side of the acceleration sensor chip facing the first cap, and the acceleration sensor in the first and second caps In the concave bottom surface facing the chip, a projection-like stopper that regulates the movement of the weight portion when receiving acceleration is formed, The first cap is joined via metal thin films formed at both ends along a direction orthogonal to the one direction on one surface of the acceleration sensor chip, and opens the orthogonal direction on the one surface. A semiconductor acceleration sensor to be put in a state. 3. A first surface of the acceleration sensor chip is provided with a wire bonding pad on one of both ends orthogonal to the one direction on one surface of the acceleration sensor chip. 2. The semiconductor acceleration sensor according to claim 1, wherein the semiconductor acceleration sensor is formed in a shape extending toward the upper side of the wire bonding pad.