JP4907181B2 - Capacitive pressure sensor - Google Patents

Description

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

  A capacitance-type physical quantity sensor, for example, a capacitance-type pressure sensor, has a substrate having a diaphragm as a movable electrode and a substrate having a fixed electrode, with a predetermined gap (cavity) between the diaphragm and the fixed electrode. It is comprised by joining. In this capacitance type pressure sensor, when pressure is applied to the diaphragm, the diaphragm is deformed, thereby changing the distance between the diaphragm and the fixed electrode. The capacitance between the diaphragm and the fixed electrode changes due to the change in the interval, and the change in pressure is detected using the change in capacitance.

In the capacitance type pressure sensor, for example, as described in Patent Document 1, a substrate 35 having a diaphragm 33 and a fixed electrode 34 formed on the bottom surface of the recess 33 is bonded to a base 32 having a diaphragm 31. Has been configured. In such a capacitive pressure sensor, when pressure is applied, the diaphragm 31 is moved and the distance from the fixed electrode 34 is changed.
Japanese Patent Laid-Open No. 9-43083

  However, in such a configuration, the capacitance is inversely proportional to the distance between the electrodes, and therefore, when the distance (gap) between the diaphragm 31 that is a movable electrode and the fixed electrode 34 is narrowed, the capacitance changes abruptly. Therefore, there is a problem that the linearity of the sensor output (capacity change with respect to pressure) is lowered. There is also a problem that the variation between individual sensors increases.

  The present invention has been made in view of this point, and an object of the present invention is to provide a capacitive pressure sensor that is excellent in linearity of capacitance change with respect to pressure and has little variation between individual sensors.

The capacitance type pressure sensor of the present invention is a capacitance type pressure sensor having a movable electrode movable by pressure and a fixed electrode arranged to face the movable electrode, wherein the movable electrode is At least one protrusion, the fixed electrode has a receiving area into which the protrusion can be inserted, and comb teeth are formed by a plurality of protrusions in the movable electrode; The accommodation region in the electrode is configured by a region between the comb teeth of the fixed electrode provided at a position facing the comb teeth of the movable electrode, and is provided between the movable electrode and the fixed electrode. The movable electrode and the fixed electrode have a support wall extending in a direction crossing the comb teeth of the fixed electrode, and the projecting portion of the movable electrode advances and retreats to and from the accommodation region of the fixed electrode. Face each other And detecting a change in capacitance by a change in facing area at.

According to this configuration, the opposed area between the movable electrode and the fixed electrode changes as the protruding portion of the movable electrode advances and retracts into the stationary electrode housing region. That is, since S (area) in the equation C = εS / d changes in proportion to the pressure, the change in capacitance changes linearly. As a result, it is possible to realize a capacitance type pressure sensor that is excellent in linearity of capacitance change with respect to pressure and has little variation between individual sensors. Further, according to this configuration, the amount of change in capacitance can be increased, the sensor sensitivity can be increased, and the protruding portion of the movable electrode can be displaced substantially vertically over the region of the support wall. As a result, even if the interval between the protruding portions is narrow, the protruding portion of the movable electrode and the protruding portion of the fixed electrode can be inserted between the protruding portions without contacting each other.

According to the present invention, there is provided a capacitive pressure sensor having a movable electrode movable by pressure and a fixed electrode disposed to face the movable electrode, wherein the movable electrode is at least one protrusion. The fixed electrode has a receiving area in which the protruding portion can be inserted, the comb electrode is formed by a plurality of protruding portions in the movable electrode, and the receiving area in the fixed electrode Is composed of a region between the comb teeth of the fixed electrode provided at a position facing the comb teeth of the movable electrode, and is provided between the movable electrode and the fixed electrode. Opposite surfaces of the movable electrode and the fixed electrode, each having a support wall extending in a direction crossing the comb teeth, and the protrusion of the movable electrode being advanced and retracted into and from the accommodating region of the fixed electrode Opposite surface at And it detects a change in capacitance by a change, excellent linearity of the capacitance change with respect to pressure, yet it is possible to provide a smaller capacitive pressure sensor variation between individual sensors.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.
(Embodiment 1)
In the present embodiment, a capacitive pressure sensor having a movable electrode movable by pressure and a fixed electrode arranged to face the movable electrode, wherein the comb is formed by a plurality of protrusions on the movable electrode. An embodiment will be described in which teeth are formed and the accommodation area in the fixed electrode is composed of an area between comb teeth extending to the movable electrode side.

  FIG. 1 is a cross-sectional view showing a schematic configuration of a capacitive pressure sensor according to Embodiment 1 of the present invention. FIG. 2 is a plan view showing a schematic configuration of the capacitive pressure sensor according to Embodiment 1 of the present invention. In FIG. 1, the number of comb teeth is made smaller than the number of comb teeth shown in FIG. 2 in order to simplify the drawing.

  In the figure, reference numeral 1 denotes a silicon substrate. An insulating layer 2 is formed on the silicon substrate 1. A fixed electrode 3 is formed on the insulating layer 2. The fixed electrode 3 has a plurality of protrusions extending in the normal direction (movable electrode side) of the main surface of the silicon substrate 1, that is, protruding from the surface of the fixed electrode 3 silicon substrate 1. In the present embodiment, the protruding portion is composed of comb teeth 3a. A space 3b between the comb teeth 3a constitutes a receiving region 3b into which a protruding portion of a movable electrode described later can be inserted.

  Insulating layers 4 and 5 for insulating the movable electrode from the movable electrode are provided on or on the side of the fixed electrode 3. The insulating layer 5 also serves to seal a space (cavity) between the fixed electrode 3 and the movable electrode. On the insulating layers 4 and 5, a movable electrode 6 that is movable by pressure is provided. The movable electrode 6 is disposed so as to face the fixed electrode 3. The movable electrode 6 has a plurality of protrusions that protrude toward the fixed electrode 3. In the present embodiment, the protruding portion is composed of comb teeth 6a.

  The movable electrode 6 is displaced up and down by being moved by pressure, and the comb teeth 6 a are inserted into a region (accommodating region) 3 b between the comb teeth 3 a of the fixed electrode 3. At this time, the comb teeth 3 a of the fixed electrode 3 are inserted into the region 6 b between the comb teeth 6 a of the movable electrode 6. In the present embodiment, one comb tooth 6a is inserted between each comb tooth 3a, that is, one comb tooth 3a is inserted between each comb tooth 6a. However, in the present invention, a plurality of other comb teeth may be inserted between the one comb teeth. The widths of the comb teeth 3a and 6a are appropriately determined in consideration of the widths of the regions 3b and 6b between the comb teeth.

  As can be seen from FIG. 2, a support wall 8 extending between the movable electrode 6 and the fixed electrode 3 and extending in a direction (A direction in the figure) across the comb tooth 3 a is provided. In the present embodiment, the support wall 8 is erected on the fixed electrode 3. By providing the support wall 8, the comb teeth 6 a of the movable electrode 6 can be displaced substantially vertically over the length region (D in the figure) of the support wall 8. As a result, even if the interval between the comb teeth 3a and 6a is narrow, the comb teeth 6a of the movable electrode 6 and the comb teeth 3a of the fixed electrode 3 can be inserted into the regions 3b and 6b without contact. In the present embodiment, the case where the support wall 8 is provided so as to extend in the direction crossing the comb teeth 3a (the A direction in the figure) has been described. There is no particular limitation on the extending direction in which the support wall 8 is provided as long as it can be displaced substantially vertically. Further, the support wall 8 may be provided on the movable electrode 6 side.

  In the capacitance type pressure sensor configured as described above, a predetermined capacitance is provided between the movable electrode 6 and the fixed electrode 3. When the movable electrode 6 is moved and displaced by the pressure, the comb teeth 6 a of the movable electrode 6 advance and retreat into the accommodation region 3 b of the fixed electrode 3. Thereby, the facing area between the comb teeth 6a of the movable electrode 6 and the comb teeth 3a of the fixed electrode 3 changes. That is, the facing area between the movable electrode 6 and the fixed electrode 3 changes. As a result, the capacitance between the movable electrode 6 and the fixed electrode 3 changes. This capacitance change is detected. Therefore, the change can be a pressure change using the capacitance as a parameter.

  In the capacitive pressure sensor according to the present embodiment, the comb teeth 6a, which are the protrusions of the movable electrode 6, advance and retreat into the housing region 3b of the fixed electrode 3, so that the movable electrode 6 and the fixed electrode 3 are opposed to each other. The area changes. That is, since S (area) in the equation C = εS / d changes in proportion to the pressure, the change in capacitance changes linearly. As a result, it is possible to realize a capacitance type pressure sensor that is excellent in linearity of capacitance change with respect to pressure and has little variation between individual sensors.

  Next, a manufacturing method of the capacitive pressure sensor of the present embodiment will be described. 3 (a) to 3 (d) and FIGS. 4 (a) to 4 (d) are cross-sectional views for explaining the method for manufacturing the capacitive pressure sensor according to the first embodiment of the present invention.

  First, as shown in FIG. 3A, an insulating layer 2 is formed on a silicon substrate 1 by thermal oxidation or the like, and polycrystalline silicon is deposited on the insulating layer 2 as a material for the fixed electrode 3 to form polycrystalline silicon. Layer 11 is formed. The polycrystalline silicon layer 11 is processed by, for example, forming a mask having an opening in the processed region on the polycrystalline silicon layer 11 and performing dry etching through the mask. As the etchant and etching conditions, those conventionally used can be used. Next, as shown in FIG. 3B, the polycrystalline silicon layer 11 is processed to form the fixed electrode 3 having the comb teeth 3a and the accommodating regions 3b between the comb teeth 3a.

  Next, as shown in FIG. 3C, an insulating layer 4 such as a silicon oxide film or a silicon nitride film for electrical separation is formed on the fixed electrode 3 and the insulating layer 2 and patterned into a predetermined shape. To do. The insulating layer 4 is processed, for example, by forming a mask having an opening in the processing region on the insulating layer 4 and etching through the mask. As the etchant and etching conditions, those conventionally used can be used. Then, a sacrificial layer 12 is formed in a region corresponding to the cavity region on the fixed electrode 3 and the insulating layer 4 and planarized. As the sacrificial layer 12, for example, a phosphorus-doped silicon oxide film (PSG) can be used. Next, as shown in FIG. 3D, polycrystalline silicon is deposited on the sacrificial layer 12 as a material for the comb teeth 6 a of the movable electrode 6 to form a polycrystalline silicon layer 13.

  Next, as shown in FIG. 4A, the polycrystalline silicon layer 13 is processed to form protrusions constituting the comb teeth 6a. Note that the processing of the polycrystalline silicon layer 13 is performed, for example, by forming a mask having an opening in the processing region on the polycrystalline silicon layer 13 and performing dry etching through the mask. As the etchant and etching conditions, those conventionally used can be used. Then, a sacrificial layer 14 is formed in a region corresponding to the movable electrode on the sacrificial layer 12 and planarized. As the sacrificial layer 14, for example, a phosphorus-doped silicon oxide film (PSG) can be used.

  Next, as shown in FIG. 4B, after the insulating layer 4 and the sacrificial layer 12 are etched into a predetermined shape, polycrystalline silicon as a material for the connection member 15 and the movable electrode 6 is deposited in the opening. Form. At this time, the polycrystalline silicon layer 13 and the polycrystalline silicon layer 16 are joined, and the movable electrode 6 is configured.

  Next, as shown in FIG. 4C, the sacrificial layers 12 and 14 are removed by etching to form the cavities 7. As the etchant and etching conditions, those conventionally used can be used. Next, an insulating layer 5 such as a silicon oxide film or a silicon nitride film is formed on the movable electrode 6 and processed so as to close the opening between the movable electrode 6 and the connection member 15. The processing of the insulating layer 5 is performed, for example, by forming a mask having an opening in the processing region on the insulating layer 5 and performing dry etching through the mask. As the etchant and etching conditions, those conventionally used can be used.

  In the capacitance type pressure sensor thus obtained, the measurement pressure can be detected based on a signal of a change in capacitance due to a change in the facing area between the movable electrode 6 and the fixed electrode 3. it can. Further, in this capacitance type pressure sensor, the facing area between the movable electrode 6 and the fixed electrode 3 is increased by the comb teeth 6 a that are the protruding portions of the movable electrode 6 being advanced and retracted into the accommodating region 3 b of the fixed electrode 3. Since it changes, the change in capacitance changes linearly. As a result, it is possible to realize a capacitance type pressure sensor that is excellent in linearity of capacitance change with respect to pressure and has little variation between individual sensors.

(Embodiment 2)
In the present embodiment, a capacitance type pressure sensor having a movable electrode movable by pressure and a fixed electrode arranged to face the movable electrode, the movable electrode being provided on the first substrate. A description will be given of an aspect in which the fixed electrode is provided on the second substrate, the fixed electrode is embedded in the first substrate, and the first substrate has an accommodation region in which the protruding portion can be inserted.

  FIG. 5 is a cross-sectional view showing a schematic configuration of a capacitive pressure sensor according to Embodiment 2 of the present invention. FIG. 6 is a plan view showing a schematic configuration of the capacitive pressure sensor according to the second embodiment of the present invention.

  In the figure, 21 indicates a glass substrate. The glass substrate 21 has a pair of opposing main surfaces 21a and 21b. A connecting member 22a and a fixed electrode 22b are embedded in a cavity 28 described later of the glass substrate 21. The connection member 22a is a connection member for a movable electrode, and is exposed at the main surfaces 21a and 21b. The fixed electrode 22b is also exposed at the main surfaces 21a and 21b. As shown in FIG. 6, the fixed electrode 22b is provided in a rectangular ring shape.

  On the connection member 22a of the main surface 21a of the glass substrate 21, a connection electrode 23 that is electrically connected to the movable electrode is formed. A lead electrode 24 a is formed on the connection member 22 a of the main surface 21 b of the glass substrate 21, and a lead electrode 24 b is formed on the fixed electrode 22 b of the main surface 21 b of the glass substrate 21. Since the lead electrodes 24a and 24b are provided on the main surface 21b as described above, the lead-out electrode to the outside can be formed on one surface, so that a device suitable for surface mounting can be obtained. As a material constituting the connection member 22a and the fixed electrode 22b, a conductive material such as silicon or metal can be used. However, as described above, the material is made of silicon in consideration of hermeticity with the glass. Is preferred.

  A concave portion 21c that is a main surface 21a of the glass substrate 21 and that accommodates the protruding portion on the movable electrode side is formed inside the fixed electrode 22b. Therefore, the fixed electrode 22b is located on the outer periphery of the recess 21c. About the width | variety of this recessed part 21c, it sets so that a protrusion part can advance and retreat, without colliding with the protrusion part by the side of a movable electrode. Moreover, there is no restriction | limiting in particular about the depth of the recessed part 21c, but it can also be set as a stopper when a high voltage | pressure is provided, and the failure | damage of a movable electrode can also be prevented.

  On the bonding surface 21d of the main surface 21a of the glass substrate 21, a silicon substrate 25 which is a movable electrode having a protruding portion 25a is bonded. The silicon substrate 25 has a recess 25b formed around the protrusion 25a so that the protrusion 25a can be displaced. For this reason, when pressure is applied to the movable electrode, the protrusion 25 a is displaced and the protrusion 25 a is inserted into the recess 21 c of the glass substrate 21. A cavity 28 is formed by the recesses 21c and 25b. Thereby, an electrostatic capacitance is generated between the movable electrode and the fixed electrode 22b.

  The interface (bonding surface 21d) between the main surface 21a of the glass substrate 21 and the silicon substrate 25 preferably has high adhesion. When the silicon substrate 25 is bonded to the glass substrate 21, the silicon substrate 25 is mounted on the bonding surface 21d of the glass substrate 21, and an anodic bonding process is performed to increase the adhesion between the substrates 21 and 25. Can do. Thus, by exhibiting high adhesiveness at the interface between the glass substrate 21 and the silicon substrate 25, it is possible to maintain high airtightness in the cavity 28 formed by the recess 25b of the silicon substrate 25 and the recess 21c of the glass substrate 21. it can.

  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, A process that causes a covalent bond at the interface. 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 11 is preferably a glass material containing an alkali metal such as sodium (for example, Pyrex (registered trademark) glass).

  When the connection member 22a and the fixed electrode 22b are made of silicon, it is preferable that the interface between the glass substrate 21 and the connection member 22a and the fixed electrode 22b is also anodic bonded. As will be described later, these interfaces are formed by pushing the connecting member 22a and the fixed electrode 22b into the glass substrate 21 under heating. Although high adhesion can be exhibited even at the interface obtained by such a method, the adhesion can be further increased by applying an anodic bonding treatment after the connecting member 22a and the fixed electrode 22b are pushed into the glass substrate 21. it can.

  In the capacitance type pressure sensor configured as described above, a predetermined capacitance is provided between the movable electrode 25 and the fixed electrode 22b. When the movable electrode 25 is moved and displaced by the pressure, the projecting portion 25a of the movable electrode 25 advances and retreats to the concave portion 21c that is an accommodation region. Thereby, the facing area between the protrusion 25a of the movable electrode 25 and the fixed electrode 22b changes. That is, the facing area between the movable electrode 25 and the fixed electrode 22b changes. As a result, the capacitance between the movable electrode 25 and the fixed electrode 22b changes. This capacitance change is detected. Therefore, the change can be a pressure change using the capacitance as a parameter.

  In the capacitive pressure sensor according to the present embodiment, the facing area between the movable electrode 25 and the fixed electrode 22b changes as the protruding portion 25a of the movable electrode 25 advances and retreats into the concave portion 21c, which is the accommodation region. That is, since S (area) in the equation C = εS / d changes in proportion to the pressure, the change in capacitance changes linearly. As a result, it is possible to realize a capacitance type pressure sensor that is excellent in linearity of capacitance change with respect to pressure and has little variation between individual sensors.

  Next, a manufacturing method of the capacitive pressure sensor of the present embodiment will be described. 7A and 7B and FIGS. 8A to 8D are cross-sectional views for explaining a method for manufacturing the capacitive pressure sensor according to the second embodiment of the present invention.

  First, a silicon substrate 25 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. 7A, an etching mask 26 is formed on one main surface of the silicon substrate 25. The etching mask 26 is formed by thermally oxidizing the silicon substrate 25 and patterning a thermal oxide film formed on the surface of the silicon substrate 25. Then, as shown in FIG. 7B, the silicon substrate 25 is dry-etched to form protruding portions 25a and recessed portions 25b. Etching etchants and etching conditions that are usually used can be used.

  Next, as shown in FIG. 8A, one main surface of the silicon substrate 27 is etched to form the protruding portions 27a for the connection member 22a and the fixed electrode 22b, and on the silicon substrate 27 on which the protruding portions 27a are formed. The glass substrate 21 is placed on the glass substrate 21, and the silicon substrate 27 and the glass substrate 21 are heated under vacuum to press the silicon substrate 27 against the glass substrate 21 and push the protrusions 27 a into the main surface 21 b of the glass substrate 21. Thus, the silicon substrate 27 and the glass substrate 21 are bonded together. The temperature at this time is not higher than the melting point of the glass and is preferably a temperature at which the glass can be deformed (for example, not higher than the softening point temperature of the glass). For example, the heating temperature is about 800 ° C. At this time, in order to further improve the adhesion at the interface between the protruding portion 27a of the silicon substrate 27 and the glass substrate 21, it is preferable to perform an anodic bonding treatment. In this case, an electrode is attached to each of the silicon substrate 27 and the glass substrate 21, 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 28 of the capacitive pressure sensor can be improved.

  Next, as shown in FIG. 8B, the main surface 21a side of the glass substrate 21 is polished so that the connection member 22a and the fixed electrode 22b are exposed on the main surface 11a, and the back surface (projecting portion 27a) of the silicon substrate 27 is exposed. Etching is performed to expose the connecting member 22a and the fixed electrode 22b on the main surface 21b of the glass substrate 21. Etching may be dry etching or wet etching. The silicon on the back surface may be removed by polishing.

  Next, as shown in FIG. 8C, a recess 21c is formed in the region between the fixed electrodes 22b of the glass substrate 21 from the main surface 21a side. The recess 21c is formed by etching or milling after patterning with a resist, for example. Next, as illustrated in FIG. 8D, the connection electrode 23 is formed on the main surface 21 a of the glass substrate 21 so as to be electrically connected to the connection member 22 a. In this case, an electrode material is deposited on the main surface 21a of the glass substrate 21, a resist film is formed thereon, and the resist film is patterned (photolithography) so that the resist film remains in the electrode formation region. The electrode material is etched using the resist film as a mask, and then the remaining resist film is removed. Next, as shown in FIG. 8D, lead electrodes 24a and 24b are formed on the main surface 21b of the glass substrate 21 so as to be electrically connected to the connection member 22a and the fixed electrode 22b. In this case, an electrode material is deposited on the main surface 21b of the glass substrate 21, a resist film is formed thereon, and the resist film is patterned (photolithography) so that the resist film remains in the electrode formation region. The electrode material is etched using the resist film as a mask, and then the remaining resist film is removed.

  Next, the silicon substrate 25 and the glass substrate 21 are aligned so that the protrusion 25a of the silicon substrate 25 faces the recess 21c of the glass substrate 21 and so that the protrusion 25a can be moved back and forth in the recess 21c. Are joined to one main surface 21a. At this time, an anodic bonding process is performed by applying a voltage of about 500 V to the silicon substrate 25 and the glass substrate 21 under heating at about 400 ° C. or lower. Thereby, the adhesiveness at the interface between the silicon substrate 25 and the glass substrate 21 becomes higher, and the airtightness of the cavity 28 can be improved.

  In the capacitive pressure sensor thus obtained, the fixed electrode 22b is electrically connected to the extraction electrode 24b, and the movable electrode is electrically connected to the extraction electrode 24a via the connection electrode 23. Therefore, the capacitance change signal detected between the movable electrode and the fixed electrode 22b can be acquired from the extraction electrodes 24a and 24b. The measured pressure can be calculated based on this signal. Further, in this capacitance type pressure sensor, the facing area between the movable electrode and the fixed electrode 22b changes as the protruding portion 25a of the movable electrode advances and retreats into the concave portion 21c which is the accommodation region. Will change linearly. As a result, it is possible to realize a capacitance type pressure sensor that is excellent in linearity of capacitance change with respect to pressure and has little variation between individual sensors.

Next, examples performed for clarifying the effects of the present invention will be described.
A capacitance type pressure sensor having the configuration shown in FIG. 1 and a capacitance type pressure sensor using a pressure-sensitive diaphragm as a movable electrode were produced, and the relationship between the capacitance and the pressure was examined for each. The result is shown in FIG. As can be seen from FIG. 9, the capacitance type pressure sensor (Example) according to the present invention has a substantially constant capacitance change in any pressure region, and a high linearity characteristic was obtained. On the other hand, in the conventional capacitive pressure sensor (conventional example), the capacity rapidly increased on the high pressure side, and the linearity was low.

  The present invention is not limited to Embodiments 1 and 2 above, and can be implemented with various modifications. The numerical values, materials, and member shapes described in the first and second embodiments are not particularly limited, and can be appropriately changed within a range where the effects of the present invention can be exhibited. 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 sectional drawing which shows schematic structure of the electrostatic capacitance type pressure sensor which concerns on Embodiment 1 of this invention. It is a top view which shows schematic structure of the electrostatic capacitance type pressure sensor which concerns on Embodiment 1 of this invention. (A)-(d) is sectional drawing for demonstrating the manufacturing method of the electrostatic capacitance type pressure sensor which concerns on Embodiment 1 of this invention. (A)-(d) is sectional drawing for demonstrating the manufacturing method of the electrostatic capacitance type pressure sensor which concerns on Embodiment 1 of this invention. It is sectional drawing which shows schematic structure of the capacitive pressure sensor which concerns on Embodiment 2 of this invention. It is a top view which shows schematic structure of the capacitive pressure sensor which concerns on Embodiment 2 of this invention. (A), (b) is sectional drawing for demonstrating the manufacturing method of the electrostatic capacitance type pressure sensor which concerns on Embodiment 2 of this invention. (A)-(d) is sectional drawing for demonstrating the manufacturing method of the electrostatic capacitance type pressure sensor which concerns on Embodiment 2 of this invention. It is a characteristic view which shows the relationship between the pressure and capacity | capacitance in an electrostatic capacitance type pressure sensor. It is a figure for demonstrating the conventional electrostatic capacitance type pressure sensor.

Explanation of symbols

1, 25, 27 Silicon substrate 2, 4, 5 Insulating layer 3, 22b Fixed electrode 3a, 6a Comb tooth 3b, 6b Housing region 7, 28 Cavity 8 Support wall 11, 13, 16 Polycrystalline silicon layer 12, 14 Sacrificial layer 21 Glass substrate 21a, 21b Main surface 21c, 25b Recess 22a Connection member 23 Connection electrode 24a, 24b Lead electrode 26 Etching mask 27a Projection

Claims (1)

A capacitance type pressure sensor having a movable electrode movable by pressure and a fixed electrode arranged to face the movable electrode, wherein the movable electrode has at least one protrusion, The fixed electrode has an accommodation area in which the protrusion can be inserted, and comb teeth are formed by a plurality of protrusions in the movable electrode, and the accommodation area in the fixed electrode is It is comprised in the area | region between the comb teeth of the said fixed electrode provided in the position facing a comb tooth, and is provided between the said movable electrode and the said fixed electrode in the direction which crosses the said comb teeth of the said fixed electrode. Due to a change in the facing area of the movable electrode and the fixed electrode facing each other by having the supporting wall extending, and the protruding portion of the movable electrode is advanced and retracted to and from the accommodating region of the fixed electrode. Stillness Capacitive pressure sensor and detects a change in capacitance.

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