JPH06273442A - Capacitance-type semiconductor acceleration sensor and its manufacture as well as mounting structure of the sensor - Google Patents

Abstract

PURPOSE:To provide an acceleration sensor where the inside of the sensor is hermetically sealed completely, the production process is simple and the sensor can be mounted easily on a circuit board or the like. CONSTITUTION:A connection hole 9 is made in a glass cover 6, a connection cover 7 is installed so as to seal the connection hole 9, gaps 13 are formed on both the right and left sides of the connection cover 7 so as not to be connected electrically to the connection cover 7, nonconductive covers 8 are pasted respectively on the glass cover 6 by an anodic bonding method. Then, a fixed electrode 5 is formed integrally on the glass cover 6 and a thinfilm conductive part 10 is formed integrally on the connection hole 9 by a sputtering method, and the fixed electrode 5 is connected electrically to the connection cover 7. This assembly and another assembly of the same constitution are pasted, by the anodic bonding method, on the surface and the rear surface of a silicon frame 1 on which a mask 3 and the like have been formed, a cutout part 12 is formed in the glass cover 6 and the nonconductive cover 8, and a movable- electrode extraction part 11 is formed on the frame 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a capacitance type semiconductor acceleration sensor, a method of manufacturing the same, and a mounting structure of the capacitance type semiconductor acceleration sensor. Specifically, the present invention relates to a capacitance type semiconductor acceleration sensor that detects displacement of a mass portion caused by acceleration or vibration as a capacitance change, a manufacturing method thereof, and a mounting structure of the capacitance type semiconductor acceleration sensor.

[0002]

2. Description of the Related Art FIG. 9 shows a sectional view of a conventional capacitance type acceleration sensor E. This acceleration sensor E can be used, for example, for detecting acceleration and impact of an automobile, and a mass portion 43 is arranged at the center of an opening portion of a frame 41 having a rectangular frame shape made of a silicon substrate. The mass portion 43 is cantilevered by the frame 41 by the two beams 42. The mass portion 43 can be freely displaced minutely in the thickness direction of the mass portion 43 by elastic deformation of the beam 42, and the upper and lower surfaces of the mass portion 43 are movable electrodes 44, respectively.

A glass substrate 46 is provided on the upper and lower surfaces of the frame 41.
And the peripheral portion of the glass substrate 46 is bonded to the frame 41 by the anodic bonding method. On the inner surface of the glass substrate 46 above and below the frame 41, the movable electrode 4 of the mass portion 43 is formed.
4, a fixed electrode 45 is provided with a small gap between the fixed electrode 45 and the movable electrode 44 of the mass portion 43, and a capacitor is formed between the fixed electrode 45.

Further, a silicon substrate 47 is laminated on the upper and lower surfaces of the frame 41 and outside the glass substrate 46. A connection hole 48 is provided in each of the upper and lower glass substrates 46, and an electrode connection portion 49 is formed by the conductive resin sealed in the connection hole 48, and the electrode connection portion 49 is a fixed electrode 4.
5 is electrically connected. In addition, the silicon substrate 47
In advance, an etching hole 50 having an opening diameter larger than that of the connection hole 48 is provided by etching, and the conductive material portion 51 is formed on the inner peripheral surface of the etching hole 50.
Is formed and the conductive material portion 51 is electrically connected to the electrode connecting portion 49, so that the fixed electrode 45 is drawn to the outside.

When manufacturing the acceleration sensor E, first, a connection hole 48 is formed in the glass substrate 46, and the connection hole 48 is filled with a conductive resin to form an electrode connection portion 49. The fixed electrode 45 formed on 46 is connected to the electrode connecting portion 49. Then, after the silicon substrate 47 having the etching holes 50 formed therein and the glass substrate 46 are joined by an anodic bonding method, this is joined to the surface of the frame 41, and finally, a conductive material made of a metal thin film or the like is formed in the etching holes 50. The portion 51 is formed, and the fixed electrode 45 is formed on the silicon substrate 4 via the electrode connecting portion 49 and the conductive material portion 51.
7 is electrically connected to the fixed electrode 45 to be drawn to the outside.

Here, the glass substrate 46 integrally bonded
When the anodic bonding of the silicon substrate 47 to the frame 41 is performed, a conductive material portion 51 is formed in the etching hole 50 to conduct the fixed electrode 45 and then a voltage is applied between the frame 41 and the silicon substrate 47 to perform anodic bonding. The movable electrode 44 and the fixed electrode 45 facing each other across the gap are electrically short-circuited by the electrostatic attraction force, and the yield of the acceleration sensor E is reduced. Therefore, as described above, the etching hole 50 is opened in the silicon substrate 47 so that the electrode connecting portion 49 and the silicon substrate 47 do not come into contact with each other, and the electrical path from the silicon substrate 47 to the fixed electrode 45 is cut off. Glass frame 46 on frame 41
After the anodic bonding of the silicon substrate 47 and the bonding is completed, the conductive material portion 51 is provided in the etching hole 50 to electrically connect the silicon substrate 47 to the fixed electrode 45, and the movable electrode 44 and the fixed electrode 45 are short-circuited. It prevents the yield from decreasing.

[0007]

As in the structure of the conventional acceleration sensor E, the electrode connection portion 49 formed by sealing the connection hole 48 with the conductive resin prevents foreign matter from entering from the outside. However, due to deterioration of the conductive resin or the like, the airtightness of the sensor interior 52 in which the mass portion 43 is formed cannot be maintained completely and for a long period of time. Therefore, it is difficult to take out the internal fixed electrode 45 to the outside while maintaining the airtightness of the sensor interior 52, and when used in a corrosive gas atmosphere, the mass portion and the beam are deteriorated or deteriorated. There was a problem with the stability of the acceleration sensor.

Further, in manufacturing the acceleration sensor E, it is necessary to open the etching hole 50 in the glass substrate 46, and to form the conductive material portion 51 in the etching hole 50 again after the anodic bonding. It took time and effort to pull it out.

Further, the method of drawing out the movable electrode 44 to the outside has not been considered.

The present invention has been made in view of the above-mentioned drawbacks of the prior art, and an object of the present invention is to make it possible to pull out the internal electrodes to the outside while completely sealing the inside of the sensor. An object of the present invention is to provide an acceleration sensor which has a simple manufacturing process and can be easily mounted on a circuit board and a manufacturing method thereof.

[0011]

In a first capacitance type semiconductor acceleration sensor according to the present invention, a mass portion supported by a beam having elasticity is provided on a support, and insulating substrates are provided on both surfaces of the support, respectively. In a capacitance type semiconductor acceleration sensor in which a fixed electrode is provided on the inner surface of at least one of the insulating substrates, the fixed electrode is penetrated through the provided insulating substrate. A semiconductor substrate is bonded to the outer surface of the insulating substrate so as to seal the connection hole, and the fixed electrode is formed by a thin film conductor formed in a region including at least the inner peripheral surface of the connection hole. And the semiconductor substrate are electrically connected to each other.

In the first capacitance type semiconductor acceleration sensor, the semiconductor substrate has a region electrically connected to the fixed electrode through a thin film conductor and a region electrically insulated from the fixed electrode. Further, the surface of the region electrically connected to the fixed electrode may be recessed inward from the surface of the region electrically insulated from the fixed electrode. Further, an insulating film may be formed on the surface of the region that is electrically connected to the fixed electrode. In that case, the region electrically connected to the fixed electrode and the region electrically insulated from the fixed electrode may be connected as a detection electrode, or the region electrically connected to the fixed electrode may be used as the detection electrode and fixed. The region electrically insulated from the electrode may be a ground electrode.

In the first capacitance type semiconductor acceleration sensor, the fixed electrode and the thin film conductor may be formed of the same material and the same forming means. Further, a high concentration impurity diffusion layer may be provided on at least one surface of the semiconductor substrate.

Further, the movable electrode is electrically connected to the outside by providing a lead-out hole penetrating the insulating substrate and the semiconductor substrate or exposing an electrode lead portion provided on the surface of the support from the insulating substrate and the semiconductor substrate. You may withdraw it.

In the second capacitance type semiconductor acceleration sensor according to the present invention, a mass portion supported by an elastic beam is provided on a support body, and an insulating substrate is bonded to both surfaces of the support body to form a movable electrode. In a capacitance type semiconductor acceleration sensor in which a fixed electrode is provided on the inner surface of at least one of the insulative substrates facing the mass part to be formed, a connection hole is provided by penetrating the insulative substrate provided with the fixed electrode. A thick film conductor is formed on an outer surface of the insulating substrate so as to seal the connection hole, and the fixed electrode and the thick film are formed by a thin film conductor formed in a region including at least an inner peripheral surface of the connection hole. It is characterized in that it is electrically connected to a conductor.

In the second capacitance type semiconductor acceleration sensor, the thick film conductor is electrically insulated from the fixed electrode and a region where the thick film conductor is electrically connected to the fixed electrode through the thin film conductor. It can be divided into regions and regions. In that case, the region electrically connected to the fixed electrode and the region electrically insulated from the fixed electrode may be connected as a detection electrode, or the region electrically connected to the fixed electrode may be used as the detection electrode and the fixed electrode The electrically insulated region may be used as a ground electrode.

In the second capacitance type semiconductor acceleration sensor, the fixed electrode and the thin film conductor may be formed of the same material and the same forming means. Further, the movable electrode may be electrically pulled out to the outside by providing a lead-out hole penetrating the insulating substrate or exposing the electrode lead-out portion provided on the surface of the support from the insulating substrate.

Further, in the first and second capacitance type semiconductor acceleration sensors, the space surrounded by the support and the insulating substrate may be sealed in a vacuum state, a reduced pressure state or a gas filled state. Further, in these capacitance type semiconductor acceleration sensors, the semiconductor substrate or the thick film conductor is bonded to the circuit pattern portion formed on the circuit board and fixed to the circuit board, and at the same time, the fixed electrode is formed on the circuit pattern portion. You may connect.

A first method for manufacturing the first capacitance type semiconductor acceleration sensor is to provide a connection hole through an insulating substrate and then to seal the connection hole. A semiconductor substrate is bonded to the outer surface of the insulating substrate, a fixed electrode is formed on the inner surface of the insulating substrate, and a thin film conductor is formed in a region including at least the inner peripheral surface of the connection hole. The method is characterized by including a step of electrically connecting to a semiconductor substrate to produce a cover, and a step of facing the fixed electrode to a mass portion and joining the cover to at least one surface of the support body. .

The second method for manufacturing the first capacitance type semiconductor acceleration sensor is to bond the semiconductor substrate to the outer surface of the insulating substrate, then pierce the insulating substrate and use the semiconductor substrate. A connection hole is provided so as to be sealed, a fixed electrode is formed on the inner surface of the insulating substrate, and a thin film conductor is formed in a region including at least the inner peripheral surface of the connection hole, and the fixed electrode is formed by the thin film conductor. And a semiconductor substrate are electrically connected to each other to produce a cover, and a step of joining the cover to at least one surface of the support with the fixed electrode facing the mass portion There is.

A third method for manufacturing the first electrostatic capacity type semiconductor acceleration sensor is to provide a fixed electrode on the inner surface of the insulating substrate after forming a connection hole through the insulating substrate. Forming and forming a thin film conductor from the inner peripheral surface of the connection hole to the outer surface of the insulating substrate, and bonding the semiconductor substrate to the outer surface of the insulating substrate to seal the connection hole, the thin film conductor A step of electrically connecting the fixed electrode and the semiconductor substrate with each other to form a cover, and a step of facing the fixed electrode to the mass part and joining the cover to at least one surface of the support. Is characterized by.

[0022]

In the acceleration sensor of the present invention, the fixed electrode inside and the external semiconductor substrate or thick film conductor are electrically connected via the thin film conductor formed in the connection hole provided in the insulating substrate. Connected. Moreover, the connection hole is surely sealed by the semiconductor substrate or the thick film conductor on the outer surface. Therefore, in the acceleration sensor, the fixed electrode inside can be taken out to the outside while surely sealing the inside of the sensor. Moreover, since the connection hole is sealed with the semiconductor substrate or the thick film conductor, the deterioration of the material is small, and the inside of the sensor can be kept in a sealed state for a long period of time. Therefore, for example, in order to protect from corrosive atmosphere gas, the inside of the sensor has a completely sealed structure, and the inside of the sensor is vacuumed,
Even when the pressure is reduced or the gas is sealed, it is possible to prevent the degree of vacuum from being lowered and the gas from leaking, and it is possible to improve the durability of the capacitance type semiconductor acceleration sensor.
Moreover, since the connection hole is sealed by the semiconductor substrate or the thick film conductor serving as an external electrode, a separate member for sealing the connection hole is not required, and the structure can be simplified.

Further, in the acceleration sensor in which the semiconductor substrate is divided into a region electrically connected to the fixed electrode and an insulated region, when the semiconductor substrate and the insulating substrate are anodically bonded to the support, By using a region insulated from the fixed electrode as an anodic bonding electrode, a voltage for anodic bonding can be applied to the support for bonding. At this time,
Since the voltage for anodic bonding is not applied to the region of the semiconductor substrate that is electrically connected to the fixed electrode, there is no risk of short circuit between the fixed electrode and the movable electrode. On the other hand, the potential of the fixed electrode can be taken out to the outside from a region that is electrically connected to the fixed electrode. Therefore, it is not necessary to provide a conductive material part or the like after the anodic bonding as in the conventional case, and the acceleration sensor can be easily manufactured. Even when the thick film conductor is divided into a region that is electrically connected to the fixed electrode and a region that is insulated, short circuit between the movable electrode and the fixed electrode during anodic bonding can be similarly prevented.

Further, if the surface of the region of the semiconductor substrate that is electrically connected to the fixed electrode is recessed from the region of the semiconductor substrate that is insulated from the fixed electrode, or if an insulator film is formed on the surface of the region of the semiconductor substrate that is electrically connected to the fixed electrode. It is possible to prevent the bonding electrode for anodic bonding from coming into contact with a region electrically connected to the fixed electrode, and it is possible to perform anodic bonding with a bonding electrode having a simple shape.

Further, if the region electrically connected to the fixed electrode and the region insulated from the fixed electrode are connected to form the detection electrode, both regions can be made to have the same potential, so that the stray capacitance generated between both regions can be made. Can be reduced. Further, by using the region insulated from the fixed electrode as the ground electrode, it is possible to reduce the stray capacitance generated in the region insulated from the fixed electrode.

If the fixed electrode and the thin film conductor are formed of the same material and the same forming means in this acceleration sensor, the fixed electrode and the semiconductor substrate can be easily electrically connected, and the fixed electrode and the thin film conductor can be easily connected. Since the thin film conductor can be formed at the same time, the manufacturing process of the acceleration sensor can be simplified.

At least one surface of the semiconductor substrate,
For example, if a high-concentration impurity diffusion layer is provided on the inner surface, the electrical connection between the thin film conductor and the semiconductor substrate can be further ensured.

Further, the movable electrode can be drawn out from a lead-out hole penetrating the insulating substrate or the semiconductor substrate, or the electrode lead-out portion of the movable electrode can be exposed from the insulating substrate or the like.
The movable electrode and the fixed electrode can be easily connected to the circuit board. When a large number of acceleration sensors are formed on the wafer, the characteristics of each acceleration sensor can be checked in the wafer state.

If the semiconductor substrate or the thick film conductor is bonded to the circuit pattern portion formed on the circuit board to fix the acceleration sensor to the circuit board, and at the same time, the fixed electrode is connected to the circuit pattern portion, By mounting the acceleration sensor on the circuit board, the fixed electrode can be connected, and the work of connecting the acceleration sensor can be facilitated.

The first and second manufacturing methods of the present invention include the first
After joining the insulating substrate and the semiconductor substrate as in the manufacturing method of 1), a connection hole is provided so as to be sealed by the insulating substrate, or connected to the insulating substrate as in the second manufacturing method. After forming the hole, the semiconductor substrate is bonded so as to seal the connection hole, then the fixed electrode is formed on the insulating substrate and the thin film conductor is formed in the region including the connection hole, and the fixed electrode is formed by the thin film conductor. And the semiconductor substrate are connected to form a cover. In this way, if you make a cover,
Since the connection hole can be easily sealed and the fixed electrode can be pulled out to the outside through the semiconductor substrate, the manufacturing process can be simplified.

Further, since the cover in which the fixed electrode is connected to the semiconductor substrate is joined to the support having the mass portion and the like formed thereon, for example, a differential electrode in which the fixed electrode is formed on the insulating substrates on both sides of the support is used. Even in the electrostatic capacity type semiconductor acceleration sensor having the structure, the fixed electrodes on both sides of the support can be simultaneously drawn to the outside.

Further, as in the third manufacturing method of the present invention,
If the fixed electrode is formed on the insulating substrate and the thin film conductor is formed from the connection hole to the outer surface of the insulating substrate, the connection between the fixed electrode and the semiconductor substrate can be further ensured.

[0033]

1 is a cross-sectional view of a capacitance type acceleration sensor A according to the present invention. The acceleration sensor A includes a frame 1 having a square frame-shaped mass portion 3 supported by a frame 1 in a cantilevered manner by two beams 2 having a shaft rod shape or a thin wall shape.
The mass portion 3 is arranged at the center of the mass portion 3 and can be freely and minutely displaced in the thickness direction of the mass portion 3 by elastic deformation of the beam 2. Further, the frame 1, the beam 2, and the mass portion 3 are integrally formed by using a crystalline silicon wafer using a semiconductor manufacturing process, and the fixed electrode 5 of the mass portion 3 is formed.
The surface 3a opposed to is functioning as the movable electrode 4.

A glass cover 6 is provided on the upper and lower surfaces of the frame 1.
Are bonded to each other, and a fixed electrode 5 is provided on the inner surface of each glass cover 6 so as to form a minute gap with the movable electrode 4 of the mass portion 3. The movable electrode 4 and the fixed electrode 5 form a capacitor. ing. Further, the glass cover 6 on the upper and lower surfaces of the frame 1 is provided with a connection hole 9 for drawing out the fixed electrode 5 to the outside.

Further, on the outside of the glass cover 6 on the upper and lower surfaces of the frame 1, silicon connection covers 7 are joined so as to seal the connection holes 9. Further, a slight gap 13 is provided on each of the left and right sides of the connection cover 7, and a silicon non-connection cover 8 is joined to both sides of the glass cover 6 so as not to be electrically connected to the connection cover 7. In this way, the connection hole 9 is sealed by the connection cover 7 and the mass portion 3 and the like are sealed inside the sensor. Therefore, the inside of the sensor is evacuated, depressurized, or filled with gas. Good.

Further, in the connection hole 9, a thin film-shaped conductive portion 10 made of a conductive material such as Au or Al is attached to the fixed electrode 5.
In addition, the fixed electrode 5 is integrally formed by sputtering, and the fixed electrode 5 is electrically connected to the connection cover 7 by the thin film conductive portion 10 and is drawn to the outside. In order to ensure electrical connection between the thin-film conductive portion 10 and the connection cover 7, a p ⁺ diffusion layer is formed on the inner surface of the connection cover 7 (or the inner surfaces of the connection cover 7 and the non-connection cover 8). is there.

On the other hand, the movable electrode 4 of the mass portion 3 is provided with the notch 12 in the glass cover 6 and the non-connecting cover 8 and the movable electrode lead-out portion 11 exposed on the frame 1
It has been pulled out. The capacitor composed of the fixed electrode 5 and the movable electrode 4 is connected to a detection circuit or the like on the circuit board on which the acceleration sensor A is mounted, and the change in capacitance thereof is detected.

However, when acceleration is applied to the acceleration sensor A, the mass portion 3 is displaced by the inertial force while elastically bending the beam 2, and the displacement of the mass portion 3 changes the capacitance of the capacitor. However, by detecting this change, the magnitude of the acceleration applied to the acceleration sensor A can be known.

FIG. 2 shows an example of a method of manufacturing the acceleration sensor A. Hereinafter, a method of manufacturing the acceleration sensor A will be described with reference to FIG. First, as shown in FIG. 2A, a plate-shaped silicon substrate 21 for manufacturing the connection cover 7 and the non-connection cover 8 and a plate-shaped glass substrate 22 for manufacturing the glass cover 6 are anodically bonded. Join at. Next, the bonded glass substrate 22 is provided with the connection hole 9 for drawing out the fixed electrode 5 by an ultrasonic processing method or the like, and the cover master 20 is manufactured. Note that, in another manufacturing method, the cover master 20 may be manufactured by joining the silicon substrate 21 and the glass substrate 22 provided with the connection holes 9 in advance.

Next, the silicon substrate 21 of the cover master 20.
A dicing groove 23 is provided on the substrate with a dicing saw until reaching the glass substrate 22, and the connecting cover 7 and the non-connecting cover 8 are provided.
Are formed respectively. Further, another wide dicing groove 24 is provided in the glass substrate 22 (the cutout 12 for drawing out the movable electrode 4 will be formed). Next, although not shown, the fixed electrode 5 is formed on the lower surface of the glass substrate 22 and the thin film conductive portion 10 such as Au or Al is integrally formed in the connection hole 9 of the glass substrate 22 by sputtering, and the fixed electrode 5 and the connection cover 7 are formed. Are electrically connected to each other to form the first cover substrate 25a [FIG.
(B)].

On the surface of the glass substrate 22 of the first cover substrate 25a, a frame substrate 26 having a large number of beams 2, mass portions 3 and frames 1 previously formed is anodically bonded [FIG. 2 (c)]. At this time, a voltage is applied to the non-connection cover 8 so as to be negative with respect to the frame substrate 26, and a voltage is applied to the connection cover 7 so as to have the same potential as the frame substrate 26 (or voltage. Anodic bonding). By applying the voltage in this way, it is possible to prevent a short circuit between the movable electrode 4 and the fixed electrode 5 and prevent the movable electrode 4 from sticking to the fixed electrode 5. In addition, it is preferable that the frame substrate 26 is formed by diffusing n layers by a thickness corresponding to the thickness of the beam 2 and the beam 2 and the like are accurately formed by using an electrochemical etching method.

Next, the second cover substrate 25b is anodically bonded to the other surface of the frame substrate 26. The second cover substrate 25b is manufactured in substantially the same manner as the first cover substrate 25a as follows. Cover master 2 of FIG. 2 (a)
The dicing groove 23 is provided in the silicon substrate 21 of 0, and the connection cover 7 and the non-connection cover 8 are manufactured. Next, the fixed electrode 5 and the thin-film conductive portion 10 are integrally formed by sputtering, the fixed electrode 5 and the connection cover 7 are electrically connected, and the second cover substrate 25b is manufactured. This second
The cover substrate 25b is subjected to anodic bonding by applying a voltage in the same manner as the first cover substrate 25a is anodically bonded [FIG. 2 (d)].

Subsequently, after the dicing groove 27 is provided at the same position as the dicing groove 24 in the non-connecting cover 8 of the first cover substrate 25a, the movable electrode lead-out portion 11 exposed in the dicing groove 24 and the connecting cover. 7 to check the characteristics of each acceleration sensor A, and finally cut at the position of the broken line shown in FIG. 2E to produce a plurality of acceleration sensors A at a time [FIG. )].

FIG. 3 shows a sectional view of an acceleration sensor B which is another embodiment of the present invention. In the acceleration sensor B,
An insulating film 14 made of an insulating material such as synthetic resin is formed on the surface of the connection cover 7, and a thin-film contact electrode 15 is provided from the connection hole 9 to the outside of the glass cover 6. The contact electrode 15 is integrally formed with the thin film conductive portion 10 and the fixed electrode 5 by sputtering. In addition, the movable electrode lead-out portion 11 on the frame 1 is a lead-out hole 1 provided in the glass cover 6 and the non-connection cover 8.
6, it can be connected to a detection circuit or the like provided on a circuit board or the like. According to the acceleration sensor B, since the contact area can be increased by the contact electrode 15, the electric resistance between the connection cover 7 and the thin film conductive portion 10 can be reduced.

When manufacturing this acceleration sensor B,
First, the connection hole 9 is formed in the glass substrate 22 that will be the glass cover 6.
Then, the fixed electrode 5 is formed on one surface of the glass substrate 22 by sputtering, the contact electrode 15 is formed on the other surface, and the thin film conductive portion 10 is integrally formed in the connection hole 9. Next, after the silicon substrate 21 is bonded by anodic bonding to produce the cover master 20, the extraction holes 16 for extracting the movable electrode 4 are provided, and thereafter, the same process as in the acceleration sensor A may be performed.

FIG. 4 shows a sectional view of an acceleration sensor C which is another embodiment of the present invention. The acceleration sensor C is manufactured so that the connection cover 7 is subjected to an etching process and is thinner than the non-connection cover 8.

FIG. 5 shows the first cover substrate 25a or the second cover substrate 25a.
FIG. 7 is an explanatory view showing an electrode arrangement of bonding electrodes 28 when the cover substrate 25b and the frame substrate 26 of FIG. In the acceleration sensor A, since the outer surface of the connection cover 7 and the outer surface of the non-connection cover 8 are on the same plane, when the frame substrate 26 is anodically bonded, as shown in FIG. 28 is provided with a recess 29, or FIG.
It is necessary to prevent the short circuit between the movable electrode 4 and the fixed electrode 5 by dividing the bonding electrode 28 as shown in (b). However, if the structure of the acceleration sensor C is used, FIG.
As shown in FIG. 4, it is not necessary to provide the concave portion 29 in the bonding electrode 28 or divide the bonding electrode 28, and the anodic bonding can be performed using the bonding electrode 28 having a simple shape without contacting the bonding electrode 28 with the connection cover 7. Can be done. Therefore, anodic bonding can be performed without causing a short circuit or sticking between the movable electrode 4 and the fixed electrode 5. Further, like the acceleration sensor B shown in FIG. 3, the insulating film 1 is formed on the connection cover 7.
By providing 4 as well, it is possible to perform anodic bonding using the bonding electrode 28 having a similarly simple shape. Although not shown, the insulating film 14 may be provided on the outer surface of the connection cover 7 after the outer surface of the connection cover 7 is recessed from the outer surface of the non-connection cover 8 by performing an etching process on the connection cover 7. Good.

FIG. 6 is a sectional view showing an acceleration sensor D which is still another embodiment of the present invention. The acceleration sensor D has a glass cover 6 joined to the upper and lower surfaces of the frame 1 on which the mass portion 3 and the beam 2 are formed. A connection hole 9 is provided in the glass cover 6, and a conductive thin film portion 10 is fixed to the connection hole 9 by sputtering so as to connect the fixed electrode 5 and a connection thick film portion 31 formed outside the glass cover 6. It is formed integrally with the electrode 5. Further, on both sides of the connection thick film portion 31, a non-connection thick film portion 32 is formed with a gap 33 provided so as not to be electrically connected to the connection thick film portion 31. Connection thick film portion 31 and non-connection thick film portion 32
Is formed of a thick film conductive material. This is formed by, for example, applying fine particles of Au, Ag or the like in a paste form with an organic binder onto the glass cover 6 by screen printing or the like, and then firing and metallizing the same. is there. At this time, it is also possible to perform overprinting to obtain a desired thickness. In addition, in this embodiment, the movable electrode lead-out portion 11 is exposed from the notch portion 12, but like the embodiment of FIG.
The movable electrode 4 may be drawn out from the drawing hole 16 provided in the glass cover 6 and the non-connection thick film portion 32.

By thus forming the connection thick film portion 31 of the thick film conductive material, the connection hole 9 of the glass cover 6 can be sealed. Further, for example, by patterning the connection thick film portion 31 and the non-connection thick film portion 32 with a thick film conductive material as shown in FIG. 7, the non-connection thick film portion 32 and the connection thick film portion 31 are formed at the time of anodic bonding. It can be used as a bonding electrode for anodic bonding, and a special bonding electrode 28 as shown in FIGS. 5 (a) and 5 (b) is not required, and anodic bonding can be easily performed.

FIG. 8 is a side view of the acceleration sensor A mounted on the circuit board 34. As shown in FIG. 8, the acceleration sensor A is mounted on the circuit pattern 36 of the circuit board 34 by a conductive fixing material 35 such as solder. The fixed electrode 5 of the upper glass cover 6 is connected to the connection pad 37 on the circuit pattern 36 from the upper connection cover 7, and the movable electrode 4 is connected to another connection pad 37 from the movable electrode lead-out portion 11 on the frame 1. Each is connected by a bonding wire 38. Fixed electrode 5 on the lower glass cover 6
Are directly connected to the circuit pattern 36 by the lower connection cover 7 and the conductive fixing material 35. Further, the upper and lower non-connection covers 8 are connected to each other so as to have the same potential as the connection cover 7 to form a detection electrode. In this way, the connecting cover 7 and the non-connecting cover 8 are connected so as to have the same potential and mounted on the circuit board 34, whereby the stray capacitance generated in the acceleration sensor A can be reduced.

Needless to say, other acceleration sensors can be similarly mounted on the circuit board. Although not shown, as another mounting mode, the connection cover 7 and the non-connection cover 8 are not connected, only the connection cover 7 is used as a detection electrode, and the non-connection cover 8 is connected to the ground line of the circuit board 34. It may be grounded.

[0052]

In the capacitance type semiconductor acceleration sensor of the present invention, the connection hole for electrically drawing out the fixed electrode to the outside is sealed by the semiconductor substrate or the thick film conductor, so that the inside of the sensor is The sealed state can be maintained for a long period of time. Therefore, for example, even if the inside of the sensor is completely sealed to protect it from corrosive atmosphere gas and the inside of the sensor is evacuated or decompressed or the gas is sealed, the degree of vacuum is reduced or gas leaks. Can be prevented, and the durability of the capacitance type semiconductor acceleration sensor can be improved.

Further, the fixed electrode is drawn to the outside by a semiconductor substrate or a thick film conductor, and the movable electrode is a lead hole provided in the semiconductor substrate or the insulating substrate, or an electrode lead portion from the semiconductor substrate or the insulating substrate. Since the electrodes are exposed and drawn out from the support body, both electrodes can be easily connected to the circuit board.

Further, since the fixed electrode and the thin film conductor are formed by the same material and the same forming means, the fixed electrode can be easily and surely connected to the semiconductor substrate or the thick film conductor, Also, the manufacturing process can be simplified. In addition, since the semiconductor substrate on which the high-concentration impurity diffusion layer is formed is used, the electrical connection between the thin film conductor and the semiconductor substrate can be ensured.

Further, since the semiconductor substrate or the thick film conductor is separately formed into the region connected to the fixed electrode and the region insulated from the fixed electrode, the fixed electrode and the movable electrode are not short-circuited. The anodic bonding can be easily performed, and the yield of the capacitance type semiconductor acceleration sensor can be easily improved.

Further, if the region of the semiconductor substrate which is electrically connected to the fixed electrode is recessed inward from the region of the semiconductor substrate which is insulated from the fixed electrode, or an insulator film is formed on the surface of the region electrically connected to the fixed electrode, the anodic bonding is performed. It is not necessary to devise a bonding electrode at that time, and a bonding electrode having a simple shape can be used. Further, since the regions electrically connected to the fixed electrodes can be used as the bonding electrodes at the time of anodic bonding, the anodic bonding can be further simplified.

Further, the region electrically connected to the fixed electrode and the region insulated from each other are connected to have the same potential, or the region insulated from the fixed electrode is used as a ground electrode to reduce the stray capacitance. can do.

In the manufacturing method of the present invention, since the connection hole can be easily sealed and the fixed electrode can be easily pulled out to the outside through the semiconductor substrate, the manufacturing process of the capacitance type semiconductor acceleration sensor is simplified. Can be converted. Further, for example, even in a capacitance type semiconductor acceleration sensor having a differential structure in which fixed electrodes are formed on insulating substrates on both sides of the support, the fixed electrodes on both sides of the support can be simultaneously drawn to the outside. Further, by forming the thin film conductor on the insulating substrate from the connection hole to the outer surface of the insulating substrate, the contact area between the thin film conductor and the semiconductor substrate can be increased, and the contact resistance can be reduced to ensure the connection. It can be something.

If the semiconductor substrate or the thick film conductor is joined to the circuit pattern portion formed on the circuit board to fix the acceleration sensor to the circuit board, and at the same time, the fixed electrode is connected to the circuit pattern portion. By mounting the acceleration sensor on the circuit board, the fixed electrode can be connected, and the work of connecting the acceleration sensor can be facilitated.

[Brief description of drawings]

FIG. 1 is a sectional view of a capacitance type acceleration sensor according to an embodiment of the present invention.

2 (a), (b), (c), (d), and (e) are cross-sectional views showing a method for manufacturing the same capacitive acceleration sensor.

FIG. 3 is a sectional view of a capacitance type acceleration sensor according to another embodiment of the present invention.

FIG. 4 is a sectional view of a capacitance type acceleration sensor which is another embodiment of the present invention.

5 (a), (b) and (c) are explanatory views showing an electrode arrangement during anodic bonding.

FIG. 6 is a cross-sectional view of a capacitance type acceleration sensor which is another embodiment of the present invention.

FIG. 7 is a plan view showing an example of a pattern of a thick film conductor portion.

FIG. 8 is a side view showing an embodiment of a mounting method of the present invention.

FIG. 9 is a cross-sectional view of a capacitance type acceleration sensor which is a conventional example.

[Explanation of symbols]

 3 Mass part 5 Fixed electrode 6 Glass cover 7 Connection cover 10 Thin film conductive part 31 Connection thick film part

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Masakazu Shiiki, Omron Co., Ltd., No. 10, Hanazono Dodo-cho, Ukyo-ku, Kyoto City, Kyoto Prefecture

Claims (22)

[Claims] 1. A mass portion supported by a beam having elasticity is provided on a support body, and insulating substrates are bonded to both surfaces of the support body so as to face the mass portion to be a movable electrode and at least one of the insulating properties is provided. In a capacitance type semiconductor acceleration sensor having a fixed electrode provided on an inner surface of a substrate, the insulating substrate is provided so as to penetrate the insulating substrate provided with the fixed electrode to form a connection hole and to seal the connection hole. A semiconductor substrate is joined to the outer surface of the substrate, and the fixed electrode and the semiconductor substrate are electrically connected by a thin-film conductor formed in a region including at least the inner peripheral surface of the connection hole. Type semiconductor acceleration sensor. 2. The semiconductor substrate is divided into a region electrically connected to the fixed electrode through a thin film conductor and a region electrically insulated from the fixed electrode. The electrostatic capacity type semiconductor acceleration sensor described in 1. 3. A surface of the region which is electrically connected to the fixed electrode,
The electrostatic capacitance type semiconductor acceleration sensor according to claim 2, wherein the electrostatic capacitance type semiconductor acceleration sensor is retracted inward from a surface of the region electrically insulated from the fixed electrode. 4. The capacitance type semiconductor acceleration sensor according to claim 2, wherein an insulating film is formed on a surface of the region which is electrically connected to the fixed electrode. 5. The electrostatic according to claim 2, 3 or 4, wherein the region electrically connected to the fixed electrode and the region electrically insulated from the fixed electrode are connected to each other to form a detection electrode. Capacitive semiconductor acceleration sensor. 6. The electrostatic capacitor according to claim 2, wherein the region electrically connected to the fixed electrode is a detection electrode, and the region electrically insulated from the fixed electrode is a ground electrode. Capacitive semiconductor acceleration sensor. 7. The capacitance type semiconductor acceleration sensor according to claim 1, wherein the fixed electrode and the thin film conductor are formed of the same material and the same forming means. 8. The capacitance type semiconductor according to claim 1, wherein a high concentration impurity diffusion layer is provided on at least one surface of the semiconductor substrate. Acceleration sensor. 9. The movable electrode is electrically drawn out from an extraction hole provided through the insulating substrate and the semiconductor substrate.
4. The capacitance type semiconductor acceleration sensor according to 4, 5, 6, 7 or 8. 10. The electrode lead-out portion of the movable electrode is provided on the surface of the support, and the electrode lead-out portion is exposed from the insulating substrate and the semiconductor substrate. 3. A capacitance type semiconductor acceleration sensor according to 3, 4, 5, 6, 7 or 8. 11. Claims 1, 2, 3, 4, 5, 6, 7,
A method for manufacturing the capacitance type semiconductor acceleration sensor according to 8, 9, or 10, which comprises forming a connection hole by penetrating an insulating substrate and then sealing the connection hole. A semiconductor substrate is bonded to the outer surface of the insulating substrate, a fixed electrode is formed on the inner surface of the insulating substrate, and a thin film conductor is formed in a region including at least the inner peripheral surface of the connection hole. A capacitance type semiconductor including a step of electrically connecting to a semiconductor substrate to produce a cover, and a step of facing the fixed electrode to a mass portion and joining the cover to at least one surface of the support body. Acceleration sensor manufacturing method. 12. The method according to claim 1, 2, 3, 4, 5, 6, 7,
A method for manufacturing the capacitance type semiconductor acceleration sensor according to 8, 9, or 10, comprising: bonding a semiconductor substrate to an outer surface of an insulating substrate, penetrating the insulating substrate, and using the semiconductor substrate. A connection hole is provided so as to be sealed, a fixed electrode is formed on the inner surface of the insulating substrate, and a thin film conductor is formed in a region including at least the inner peripheral surface of the connection hole, and the fixed electrode is formed by the thin film conductor. And a semiconductor substrate are electrically connected to each other to form a cover, and a step of facing the fixed electrode to the mass portion and joining the cover to at least one surface of the support body is a capacitive type. Manufacturing method of semiconductor acceleration sensor. 13. The method according to claim 1, 2, 3, 4, 5, 6, 7,
A method for manufacturing the electrostatic capacity type semiconductor acceleration sensor according to 8, 9, or 10, wherein a fixed electrode is provided on an inner surface of the insulating substrate after the insulating substrate is provided with a connection hole. Forming and forming a thin film conductor from the inner peripheral surface of the connection hole to the outer surface of the insulating substrate, and bonding the semiconductor substrate to the outer surface of the insulating substrate to seal the connection hole, the thin film conductor A step of electrically connecting the fixed electrode and the semiconductor substrate with each other to produce a cover, and a step of facing the fixed electrode to the mass part and joining the cover to at least one surface of the support. Manufacturing method of capacitance type semiconductor acceleration sensor. 14. A mass portion supported by a beam having elasticity is provided on a support body, and an insulating substrate is bonded to both surfaces of the support body so as to face the mass portion to be a movable electrode and at least one of the insulating properties is provided. In a capacitance type semiconductor acceleration sensor having a fixed electrode provided on an inner surface of a substrate, the insulating substrate is provided so as to penetrate the insulating substrate provided with the fixed electrode to form a connection hole and to seal the connection hole. A thick-film conductor is formed on the outer surface of, and the fixed electrode and the thick-film conductor are electrically connected by a thin-film conductor formed in a region including at least the inner peripheral surface of the connection hole, Capacitive semiconductor acceleration sensor. 15. The thick film conductor is divided into a region electrically connected to the fixed electrode through a thin film conductor and a region electrically insulated from the fixed electrode. Item 15. The capacitance type semiconductor acceleration sensor according to Item 14. 16. The capacitance type semiconductor acceleration according to claim 15, wherein the region electrically connected to the fixed electrode and the region electrically insulated from the fixed electrode are connected to form a detection electrode. Sensor. 17. The capacitance type semiconductor acceleration according to claim 15, wherein the region electrically connected to the fixed electrode is a detection electrode, and the region electrically insulated from the fixed electrode is a ground electrode. Sensor. 18. The capacitance type semiconductor acceleration sensor according to claim 14, 15, 16 or 17, wherein the fixed electrode and the thin film conductor are formed of the same material and the same forming means. 19. The movable electrode is electrically drawn out from an extraction hole provided through the insulating substrate.
8. A capacitance type semiconductor acceleration sensor according to item 8. 20. The electrode lead-out portion of the movable electrode is provided on the surface of the support, and the electrode lead-out portion is exposed from the insulating substrate.
15. A capacitance type semiconductor acceleration sensor according to 15, 16, 17, 18 or 19. 21. The space surrounded by the support and the insulating substrate is sealed in a vacuum state, a reduced pressure state or a gas filled state.
6,7,8,9,10,14,15,16,17,1
8. The capacitance type semiconductor acceleration sensor according to 8, 19, or 20. 22. Claims 1, 2, 3, 4, 5, 6, 7,
8, 9, 10, 14, 15, 16, 17, 18, 19,
20. A structure in which the capacitance type semiconductor acceleration sensor according to 20 or 21 is mounted on a circuit board, wherein the semiconductor substrate or the thick film conductor is bonded to a circuit pattern portion formed on the circuit board to obtain the acceleration. A mounting structure for a capacitance type semiconductor acceleration sensor, characterized in that the sensor is fixed to a circuit board and the fixed electrode is connected to a circuit pattern portion.