JP2008039595A - Capacitance acceleration sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a small and highly sensitive capacitance acceleration sensor. <P>SOLUTION: In the capacitance acceleration sensor 1, a movable electrode 11a has a spindle section 11c and comb-teeth 11d, stretching from this spindle section 11c directed in the directions of Y. This spindle section 11c is connected to a silicon substrate 11 via spring sections 11f. The spring sections 11f are capable of expanding and contracting in the Y directions. The spindle section 11c and the-comb teeth 11d, connected to the silicon substrate 11 via the spring sections 11f, are movable in the monoaxial directions of Y. A fixed electrode 11b has comb-teeth 11e provided so as to face the comb-teeth 11d of the movable electrode 11a. The movable electrode 11a and the fixed electrode 11b are electrically connected to extraction electrodes 14a, 14b respectively via connections 11g that is integrally united with the silicon substrate 11. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a capacitance type acceleration sensor that detects acceleration using capacitance.

  The capacitance type acceleration sensor is configured by joining a substrate having a swing member, which is a movable electrode, and a substrate having a fixed electrode so as to have a predetermined interval between the swing member and the fixed electrode. Has been. In this capacitance type acceleration sensor, when acceleration is applied to the swing member, the swing member swings, thereby changing the interval between the swing member and the fixed electrode. The capacitance between the oscillating member and the fixed electrode changes due to the change in the interval, and the change in acceleration is detected using this change in capacitance (Patent Document 1).

Further, in the capacitance type acceleration sensor, the fixed electrode and the movable electrode are configured in a comb shape, and when the acceleration is applied to the movable electrode, the interval between the movable electrode and the fixed electrode is changed. There is also one that detects a change in the above (Patent Document 2).
JP-A-6-82474 JP 9-2111022 A

  However, a conventional capacitive acceleration sensor having a comb-shaped electrode is, for example, a surface MEMS (micro electro mechanical systems) type using a silicon thin film forming technique, and a silicon layer constituting the comb-shaped electrode. Must be formed by polysilicon film formation. For this reason, the thickness of the comb teeth cannot be increased, and it is difficult to obtain a highly sensitive capacitive acceleration sensor.

  On the other hand, in the bulk type that forms a comb-teeth shape by etching a silicon substrate, it is advantageous to increase the thickness to achieve high sensitivity, but to make each electrode and their external connection part in a separate process. Therefore, there is a problem that the work constant increases and the resistance at the connection portion increases. Further, there is a limit to reducing the width direction of the comb teeth due to a problem in strength, and this is an obstacle to miniaturization.

  The present invention has been made in view of such a point, and solves the problems of the conventional bulk type while being a bulk type in which the comb-like movable electrode and the fixed electrode are formed of a silicon substrate, and is small and high in size. It is an object of the present invention to provide a capacitive acceleration sensor with sensitivity and low resistance, that is, a power saving type.

  The capacitance-type acceleration sensor of the present invention is supported by an elastic beam, and is opposed to a comb-like movable electrode that moves by an inertial force due to acceleration, with a minute gap between the movable electrode. A capacitance-type acceleration sensor for detecting a change in capacitance between the two electrodes, wherein the movable electrode and the fixed electrode have a thickness within one silicon substrate. The silicon substrate further includes a connection portion to the outside of each electrode protruding from the layer on which the electrode is formed, and the pair of glass substrates partially cavities. The movable electrode and the fixed electrode are joined to both surfaces of the silicon substrate so that the movable electrode and the fixed electrode are disposed in the cavity, and the connection portion is on at least one main surface of the glass substrate. To expose to the outside As, characterized in that through said glass substrate.

  According to this configuration, the comb teeth of the movable electrode and the fixed electrode can be made as thick as the silicon substrate. For this reason, since the number of comb teeth can be reduced, a small and highly sensitive acceleration sensor can be realized. Furthermore, since the connection portion is made of the same material as the silicon substrate, the resistance at the lead portion of the movable electrode and the fixed electrode can be reduced.

  The capacitance-type acceleration sensor of the present invention is supported by an elastic beam, and is opposed to a comb-like movable electrode that moves by an inertial force due to acceleration, with a minute gap between the movable electrode. A capacitance type acceleration sensor for detecting a change in capacitance between the two electrodes, wherein the movable electrode and the fixed electrode have a thickness within one silicon substrate. The silicon substrate is formed such that a pair of glass substrates partially form a cavity, and the movable electrode and the fixed electrode are disposed in the cavity. It is bonded to both surfaces, and the comb teeth of the fixed electrode are partially embedded in one of the glass substrates.

  According to this configuration, since the comb teeth of the fixed electrode can be reliably supported, even if the width of the comb teeth is reduced and the size is reduced, each comb tooth has sufficient strength not to be deformed. In addition, a capacitive acceleration sensor that exhibits stable characteristics can be obtained.

  The capacitive acceleration sensor of the present invention may have a structure having both of the above-described structural features. As a result, it is possible to provide a sensor with high sensitivity, low connection resistance, and stable characteristics, while realizing downsizing as a main problem.

  In the capacitive acceleration sensor of the present invention, the interface between the glass substrate and the silicon substrate preferably has a Si—Si bond or a Si—O bond. According to this configuration, silicon and glass are firmly bonded to each other, and extremely high adhesion is exhibited at the interface between the two, so that the airtightness in the cavity can be improved.

  The method of manufacturing a capacitive acceleration sensor according to the present invention includes a step of manufacturing a silicon substrate having a movable electrode, a fixed electrode, and a connecting portion of each electrode, and the connecting portion of the silicon substrate is used as a first glass substrate. A step of embedding the connection portion in the first glass substrate, a step of forming comb teeth for the movable electrode and a comb tooth for the fixed electrode on the silicon substrate, and the movable electrode and the fixed electrode are in the cavity. And a step of bonding the silicon substrate and the second glass substrate so as to be disposed on each other. According to this method, a small and highly sensitive capacitive acceleration sensor can be easily obtained.

  In the present invention, a comb-like movable electrode supported by an elastic beam and moved by an inertial force due to acceleration, and a comb-like fixed electrode facing each other with a minute gap between the movable electrode A capacitance-type acceleration sensor that detects a change in capacitance between the two electrodes, wherein the movable electrode and the fixed electrode have the same height in the thickness direction in one silicon substrate. The silicon substrate further includes a connection portion to the outside of each electrode protruding from the layer on which the electrode is formed, and the pair of glass substrates partially constitute a cavity; and The movable electrode and the fixed electrode are bonded to both surfaces of the silicon substrate so as to be disposed in the cavity, and the connection portion is exposed to the outside on at least one main surface of the glass substrate. And the above Because through the scan board, it is possible to provide a highly sensitive capacitive acceleration sensor compact.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.
1A and 1B are diagrams showing a capacitive acceleration sensor according to an embodiment of the present invention. FIG. 1A is a sectional view and FIG. 1B is a plan view.

  A capacitive acceleration sensor 1 shown in FIG. 1A includes a silicon substrate 11 having a movable electrode 11a and a fixed electrode 11b, and a pair of glass substrates 12 and 13 disposed so as to sandwich the silicon substrate 11. And is composed mainly of.

  As shown in FIG. 1B, the movable electrode 11a has a weight portion 11c, and has comb teeth 11d extending from the weight portion 11c in the Y direction in FIG. 1B. The weight portion 11c is connected to the silicon substrate 11 via the spring portion 11f. The spring portion 11f is extendable in the Y direction in FIG. Therefore, the weight part 11c and the comb teeth 11d connected to the silicon substrate 11 via the spring part 11f are movable in the uniaxial direction of the Y direction in FIG. The weight part 11c and the comb teeth 11d of the silicon substrate 11 are supported by elastic beams and move by an inertial force due to acceleration. A comb-like fixed electrode is provided which is opposed to the movable electrode with a minute gap.

  The fixed electrode 11b has comb teeth 11d extending in the Y direction in FIG. The comb teeth 11d are arranged so as to face the comb teeth 11d of the movable electrode 11a. Therefore, the comb teeth 11e of the fixed electrode 11b are provided so as to extend between the comb teeth 11d of the movable electrode 11a. The comb teeth 11d of the movable electrode 11a and the comb teeth 11e of the fixed electrode 11b are opposed to each other so that a predetermined capacity is provided between the comb teeth 11d and 11e. The silicon substrate 11 is provided with a space portion 11h that is a minute gap so that the movable electrode 11a can move. The comb teeth move in the space portion 11h. Thereby, the change of the electrostatic capacitance between the movable electrode 11a and the fixed electrode 11b can be detected.

  Here, since the movable electrode 11a, the fixed electrode 11b, the weight part 11c and the spring part 11f are formed by processing on the silicon substrate 11, the thickness of the movable electrode 11a, the fixed electrode 11b, the weight part 11c and / or the spring part 11f is formed. The thickness is substantially the same as the thickness of the silicon substrate 11. However, the thickness of the movable electrode 11a, the fixed electrode 11b, the weight portion 11c, and the spring portion 11f may be different from the thickness of the silicon substrate 11 within a range not impairing the effects of the present invention. Thus, by increasing the thickness of at least the movable electrode 11a and the fixed electrode 11b to the same extent as the silicon substrate, the facing area between the comb teeth 11d of the movable electrode 11a and the comb teeth 11e of the fixed electrode 11b is increased. Therefore, a highly sensitive capacitive acceleration sensor can be realized.

  The comb teeth 11e of the fixed electrode 11b are partially embedded in the glass substrate 13 as shown in FIGS. 4 (a) and 4 (b). As a result, the comb teeth 11e of the fixed electrode 11b can be reliably supported, so that even if the width of the comb teeth 11e is reduced and the size is reduced, the fixed electrode 11b is stable, and the static electricity that exhibits stable characteristics is exhibited. A capacitive acceleration sensor can be obtained.

  The movable electrode 11a has a connecting portion 11g embedded in the glass substrate (here, the glass substrate 13) so as to be exposed on the main surface 13a of one of the pair of glass substrates 12, 13 (here, the glass substrate 13). Have. The connection portion 11g is configured integrally with the silicon substrate 11. That is, the connecting portion 11g is made of the same material as that of the silicon substrate 11, and is formed by processing the silicon substrate 11. Lead electrodes 14 a and 14 b are formed on the exposed portion of the connecting portion 11 g on the main surface 13 a of the glass substrate 13. As described above, the connection portion 11g, which is a lead portion for the lead electrodes 14a and 14b, is made of the same material as that of the silicon substrate 11, so that the resistance in the lead portion of the movable electrode 11a and the fixed electrode 11b can be reduced.

  As shown in FIG. 1A, one main surface of a silicon substrate 11 is bonded on one glass substrate 12, and the other glass substrate 13 is bonded on the other main surface of the silicon substrate 11. Yes. The glass substrate 12 has a recess that constitutes a cavity, and a movable electrode 11a, a fixed electrode 11b, a weight portion 11c, and a spring portion are formed in a cavity 15 formed by bonding the glass substrate 12 and the silicon substrate 11. 11f is arranged. Therefore, the positions of the recesses formed in the glass substrates 12 and 13 are appropriately determined by the movable electrode 11a, the fixed electrode 11b, the weight portion 11c, and the spring portion 11f in the silicon substrate 11. Although FIG. 1A illustrates the case where the pair of glass substrates 12 and 13 are formed with recesses, in the present invention, the movable electrode 11a, the weight portion 11c, and the spring portion in the silicon substrate 11 are described. Since any configuration is possible as long as 11f is movable, a recess may be provided on the upper surface of the silicon substrate 11 so as to form a cavity.

  A through hole is formed in the glass substrate 13, and a connecting portion 11g of the silicon substrate 11 is embedded in the through hole. The connecting portions 11g are exposed at the main surface 13a of the glass substrate 13, and are electrically connected to the extraction electrodes 14a and 14b, respectively. Therefore, the movable electrode 11a is electrically connected to the extraction electrode 14a provided on the main surface 13a of the glass substrate 13 via the connection portion 11g, and the fixed electrode 11b is connected to the glass substrate 13 via the connection portion 11g. The lead electrode 14b provided on the main surface 13a is electrically connected. In this way, by providing the movable electrode lead electrode and the fixed electrode lead electrode on the surface of one glass substrate, the capacitive acceleration sensor can be directly surface mounted or wire bonded. Become. As a result, the capacitive acceleration sensor can be made into one chip. In this case, since the casing of the capacitive acceleration sensor is not necessary, the size can be further reduced.

  As described above, in the capacitive acceleration sensor according to the present embodiment, the movable electrode and the fixed electrode are formed in the same height layer in the thickness direction in one silicon substrate, and the electrode is formed on the silicon substrate. Each of the electrodes protruding from the layer is connected to the outside of the electrode, and a pair of glass substrates are bonded to both surfaces of the silicon substrate so as to partially form a cavity, and the movable electrode and the fixed electrode are formed in the cavity. It is arranged inside and takes the composition which has penetrated the glass substrate so that a connection part may be exposed outside on the principal surface of at least one glass substrate. Preferably, the comb teeth of the fixed electrode are partially embedded in one glass substrate.

  The interface between the silicon substrate 11 and the glass substrates 12 and 13 preferably has high adhesion. When the silicon substrate 11 is bonded to the glass substrates 12 and 13, the silicon substrate 11 is mounted on the bonding surfaces of the glass substrates 12 and 13 and subjected to anodic bonding treatment, whereby the silicon substrate 11 and the glass substrates 12 and 13 are mounted. The adhesion between the two can be increased. Thus, by exhibiting high adhesion at the interface between the glass substrates 12 and 13 and the silicon substrate 11, the airtightness in the cavity 15 can be kept high. By increasing the airtightness in the cavity 15 as described above, the movable member such as the movable electrode is not subjected to the viscous resistance of air in the cavity 15 and exhibits high sensitivity to acceleration.

  Here, the anodic bonding treatment is performed by applying a predetermined voltage (for example, 300 V to 1 kV) at a predetermined temperature (for example, 400 ° C. or lower), thereby generating a large electrostatic attraction between silicon and glass, This refers to a treatment in which a chemical bond via oxygen is formed at the glass-silicon interface in contact, or a covalent bond is formed by releasing oxygen. The covalent bond at this interface is a Si—Si bond or a Si—O bond between the Si atom of silicon and the Si atom contained in the glass. Therefore, silicon and glass are firmly bonded by this Si—Si bond or Si—O bond, and very high adhesion is exhibited at the interface between the two. In order to perform such anodic bonding efficiently, the glass material of the glass substrate 12 is preferably a glass material containing an alkali metal such as sodium (for example, Pyrex (registered trademark) glass).

  In the capacitance type acceleration sensor having such a configuration, a predetermined capacitance is provided between the comb teeth 11d of the movable electrode 11a and the comb teeth 11e of the fixed electrode 11b. When acceleration is applied to the acceleration sensor, the movable electrode 11a is moved and displaced according to the acceleration. At this time, the electrostatic capacitance between the comb teeth 11d of the movable electrode 11a and the comb teeth 11e of the fixed electrode 11b changes. Therefore, using this capacitance as a parameter, the change can be an acceleration change. Further, according to this configuration, the thickness of the comb teeth 11d and 11e of the movable electrode 11a and the fixed electrode 11b can be made as thick as the silicon substrate 11, and the width of the comb teeth 11d and 11e can be reduced. Therefore, a small and highly sensitive acceleration sensor can be realized. Furthermore, since the connecting portion 11g, which is a lead portion for the lead electrodes 14a and 14b, is made of the same material as the silicon substrate 11, the resistance in the lead portion of the movable electrode 11a and the fixed electrode 11b can be reduced.

  Next, a manufacturing method of the capacitive acceleration sensor of the present embodiment will be described. 2 (a) to 2 (c), 3 (a), 3 (b) and 5 (a), 5 (b) illustrate a method for manufacturing a capacitive acceleration sensor according to an embodiment of the present invention. It is sectional drawing for doing. In the method of manufacturing a capacitive acceleration sensor according to the present embodiment, a silicon substrate having a movable electrode, a fixed electrode, and a connection portion of each electrode is manufactured, and the connection portion of the silicon substrate is used as a first glass substrate. The connecting portion is embedded in the first glass substrate to form comb teeth for the movable electrode and comb teeth for the fixed electrode on the silicon substrate, and the movable electrode and the fixed electrode are disposed in the cavity. In this way, the silicon substrate and the second glass substrate are bonded together.

  When manufacturing the capacitive acceleration sensor according to the present embodiment, the silicon substrate 11 having the connection portion 11g of the movable electrode 11a and the fixed electrode 11b is manufactured, and the connection portion 11g of the silicon substrate 11 is pushed into the glass substrate 13. Thus, the connecting portion 11g is embedded in the glass substrate 13, the comb teeth 11d for the movable electrode and the comb teeth 11e for the fixed electrode are formed on the silicon substrate 11, and the movable electrode 11a and the fixed electrode 11b are disposed in the cavity 15. In this way, the silicon substrate 11 and the glass substrate 12 are bonded together. In this case, the silicon substrate 11 and the glass substrates 12 and 13 may be bonded after the movable electrode 11a and the fixed electrode 11b are formed on the silicon substrate 11.

  First, a silicon substrate 11 having a low resistance by doping impurities is prepared. The impurity may be an n-type impurity or a p-type impurity. The resistivity is, for example, about 0.01 Ω · cm. Then, as shown in FIG. 2A, one main surface of the silicon substrate 11 is etched to form a recess 11i for forming a comb tooth. In this case, a resist film is formed on the silicon substrate 11, and the resist film is patterned (photolithography) so that the resist film remains in a region other than the recess formation region, and silicon is etched using the resist film as a mask, Thereafter, the remaining resist film is removed. In this way, the recess 11i is provided. Further, as shown in FIG. 2B, a connection portion 11g is formed on the surface of the silicon substrate 11 on the side where the recess 11i is formed. In this case, a resist film is formed on the silicon substrate 11, the resist film is patterned (photolithography) so that the resist film remains in the connection portion formation region, and the silicon is etched using the resist film as a mask, and then remains. The resist film is removed. In this way, the connecting portion 11g is provided. Note that dry etching is used as the etching. Thereby, the protrusion 11j is formed on the silicon substrate 11.

  Next, as shown in FIG. 2 (c), a glass substrate 13 is placed on the silicon substrate 11 on which the connecting portion 11g is formed, and the silicon substrate 11 and the glass substrate 13 are heated under vacuum, so that the silicon substrate 11 is made of glass. The connection part 11g is pushed into the glass substrate 13 by pressing against the substrate 13 to join the silicon substrate 11 and the glass substrate 13 together. The temperature at this time is preferably a temperature below the melting point of silicon and capable of deforming the glass (for example, below the softening point temperature of the glass). For example, the heating temperature is about 800 ° C.

  Furthermore, in order to further improve the adhesion at the interface between the connection portion 11g of the silicon substrate 11 and the glass substrate 13, it is preferable to perform an anodic bonding treatment. In this case, an electrode is attached to each of the silicon substrate 11 and the glass substrate 13, and a voltage of about 300 V to 1 kV is applied under heating at about 400 ° C. or lower. Thereby, the adhesiveness at the interface between the two becomes higher, and the airtightness of the cavity 15 of the capacitive acceleration sensor can be improved. Next, one main surface side of the glass substrate 13 is polished (lapped) to expose the connection portion 11g of the silicon substrate 11 on the main surface 13a.

  Next, as shown in FIG. 3A, a pattern including a movable electrode 11a, a fixed electrode 11b, a weight portion 11c, and a spring portion 11f is formed on the silicon substrate 11. In this case, a pattern is formed on the silicon substrate 11 by dry etching using the mask having the pattern. By processing the silicon substrate 11 by dry etching in this manner, the silicon substrate 11 can be etched relatively deeply, so that the thickness of the comb teeth 11d and 11e can be increased, and the facing area of the comb teeth 11d and 11e can be increased. Can do. As a result, a highly sensitive capacitive acceleration sensor can be realized.

  Next, as shown in FIG. 3B, the glass substrate 13 is etched using the pattern formed on the silicon substrate 11 as a mask to form comb teeth 11d for movable electrodes and comb teeth 11e for fixed electrodes. In this case, part of the fixed electrode comb teeth 11 e is embedded in the glass substrate 13. By performing etching of the glass substrate 13 by isotropic wet etching or dry etching, as shown in FIG. 4A, a tapered portion 13b is formed in the embedded portion of the comb teeth 11e in the glass substrate 13, As shown in FIG. 4B, the embedded portion of the comb teeth 11e in the glass substrate 13 is substantially flat. Note that the embedded portion of the comb teeth 11e in the glass substrate 13 has a configuration as shown in FIGS. 4A and 4B. In other drawings, this configuration is used to simplify the drawing. Not shown.

  Next, as shown in FIG. 5A, the glass substrate 12 in which the cavity recess is formed in advance is bonded to the silicon substrate 11 so that the recess faces the silicon substrate 11. At this time, the anodic bonding process is performed by applying a voltage of about 500 V to the silicon substrate 11 and the glass substrate 12 under heating at about 400 ° C. or lower. Thereby, the adhesiveness at the interface between the silicon substrate 11 and the glass substrate 12 becomes higher, and the airtightness of the cavity 15 can be improved. Thereby, a cavity 15 is formed between the concave portion of the glass substrate 12 and the silicon substrate 11. In the cavity 15, the movable electrode 11a, the fixed electrode 11b, the weight part 11c, and the spring part 11f are located.

  Next, as illustrated in FIG. 5B, lead electrodes 14 a and 14 b are formed on the connection portion 11 g exposed on the main surface 13 a of the glass substrate 13. In this case, an electrode material is deposited on the main surface 13a of the glass substrate 13, a resist film is formed thereon, and the resist film is patterned (photolithography) so that the resist film remains in the extraction electrode formation region. The electrode material is etched using the resist film as a mask, and then the remaining resist film is removed. In this way, the extraction electrodes 14a and 14b are provided.

  In the capacitive acceleration sensor thus obtained, the movable electrode 11a is electrically connected to the extraction electrode 14a via the connection portion 11g, and the fixed electrode 11b is electrically connected to the extraction electrode 14b via the connection portion 11g. Connected. Therefore, the capacitance change signal detected between the comb teeth 11d of the movable electrode 11a and the comb teeth 11e of the fixed electrode 11b can be acquired from the extraction electrodes 14a and 14b. The measured acceleration can be calculated based on this signal.

  In this capacitance type acceleration sensor, the comb teeth 11d of the movable electrode 11a and the comb teeth 11e of the fixed electrode 11b can be made as thick as the silicon substrate 11. For this reason, a highly sensitive acceleration sensor is realizable. Further, in this capacitive acceleration sensor, the comb teeth 11d and 11e of the movable electrode 11a and the fixed electrode 11b can be made as thick as the silicon substrate 11, and the width of the comb teeth 11d and 11e can be increased. Since it can be narrowed, a small and highly sensitive acceleration sensor can be realized. Furthermore, since the connecting portion 11g, which is a lead portion for the lead electrodes 14a and 14b, is made of the same material as the silicon substrate 11, the resistance in the lead portion of the movable electrode 11a and the fixed electrode 11b can be reduced.

  The present invention is not limited to the embodiment described above, and can be implemented with various modifications. For example, in the structure shown in FIG. 1B, the movable electrode and the weight portion can be expanded and contracted in the Y-axis direction, and components in the Y-axis direction are detected. When detecting the component in the X-axis direction, the structure shown in FIG. Thereby, the movable electrode and the weight portion can be configured to be extendable and contractible in the X-axis direction, and the component in the X-axis direction can be detected. Further, in order to be able to detect the component in the X-axis direction and the component in the Y-axis direction, the structure shown in FIG. 1B and a structure obtained by rotating the structure shown in FIG. Or it can implement | achieve by installing side by side.

  In addition, the structures and shapes of the movable electrode, the fixed electrode, the weight portion, and the spring portion in the capacitive acceleration sensor of the present invention are not particularly limited as long as they do not depart from the intended scope. Moreover, there is no restriction | limiting in particular about the numerical value and material which were demonstrated by the said embodiment. In addition, the etching and deposition process in the above embodiment are performed under the conditions that are usually used. Further, the process described in the above embodiment is not limited to this, and the process may be performed by changing the order as appropriate. Other modifications may be made as appropriate without departing from the scope of the object of the present invention.

It is a figure which shows the capacitive acceleration sensor which concerns on embodiment of this invention, Fig.1 (a) is sectional drawing, FIG.1 (b) is a top view. (A)-(c) is sectional drawing for demonstrating the manufacturing method of the capacitive acceleration sensor which concerns on embodiment of this invention. (A), (b) is sectional drawing for demonstrating the manufacturing method of the capacitive acceleration sensor which concerns on embodiment of this invention. (A), (b) is sectional drawing for demonstrating the structure of the comb-tooth of the capacitive acceleration sensor which concerns on embodiment of this invention. (A), (b) is sectional drawing for demonstrating the manufacturing method of the capacitive acceleration sensor which concerns on embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Capacitance type acceleration sensor 11 Silicon substrate 11a Movable electrode 11b Fixed electrode 11c Weight part 11d, 11e Comb tooth 11f Spring part 11g Connection part 12, 13 Glass substrate 14a, 14b Lead electrode 15 Cavity

Claims (5)

  A comb-like movable electrode supported by an elastic beam and moved by an inertial force due to acceleration; and a comb-like fixed electrode facing the movable electrode with a minute gap between the movable electrode, A capacitance type acceleration sensor for detecting a change in capacitance between both electrodes, wherein the movable electrode and the fixed electrode are formed in a layer of the same height in a thickness direction in one silicon substrate, The silicon substrate further includes a connection portion to the outside of each electrode protruding from the layer on which the electrode is formed, and a pair of glass substrates partially constitutes a cavity, and the movable electrode and the The glass substrate is bonded to both surfaces of the silicon substrate so that a fixed electrode is disposed in the cavity, and the connection portion is exposed to the outside on at least one main surface of the glass substrate. Through Capacitive acceleration sensor according to claim Rukoto.   A comb-like movable electrode supported by an elastic beam and moved by an inertial force due to acceleration; and a comb-like fixed electrode facing the movable electrode with a minute gap between the movable electrode, A capacitance type acceleration sensor for detecting a change in capacitance between both electrodes, wherein the movable electrode and the fixed electrode are formed in a layer of the same height in the thickness direction in one silicon substrate, A pair of glass substrates are bonded to both surfaces of the silicon substrate so as to partially constitute a cavity and so that the movable electrode and the fixed electrode are disposed in the cavity. A capacitance type acceleration sensor, wherein comb teeth are partially embedded in one of the glass substrates.   The capacitive acceleration sensor according to claim 1, wherein the comb teeth of the fixed electrode are partially embedded in one of the glass substrates.   4. The capacitive acceleration sensor according to claim 1, wherein an interface between the glass substrate and the silicon substrate has a Si—Si bond or a Si—O bond. 5.   A step of fabricating a silicon substrate having a movable electrode and a fixed electrode, and a connection portion of each electrode, and the connection portion of the silicon substrate is pushed into the first glass substrate to embed the connection portion in the first glass substrate. A step of forming comb teeth for a movable electrode and a comb tooth for a fixed electrode on the silicon substrate; and the silicon substrate and the second glass substrate so that the movable electrode and the fixed electrode are disposed in a cavity. A method of manufacturing a capacitance type acceleration sensor.

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