WO2016103342A1 - Capteur inertiel et son procédé de fabrication - Google Patents

Capteur inertiel et son procédé de fabrication Download PDF

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Publication number
WO2016103342A1
WO2016103342A1 PCT/JP2014/084058 JP2014084058W WO2016103342A1 WO 2016103342 A1 WO2016103342 A1 WO 2016103342A1 JP 2014084058 W JP2014084058 W JP 2014084058W WO 2016103342 A1 WO2016103342 A1 WO 2016103342A1
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Prior art keywords
inertial sensor
electrode
layer
fixed electrode
mass body
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PCT/JP2014/084058
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English (en)
Japanese (ja)
Inventor
貴支 塩田
佐久間　憲之
礒部　敦
千咲紀 田窪
雄大 鎌田
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株式会社日立製作所
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Priority to PCT/JP2014/084058 priority Critical patent/WO2016103342A1/fr
Publication of WO2016103342A1 publication Critical patent/WO2016103342A1/fr

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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01P—MEASURING LINEAR OR ANGULAR SPEED, ACCELERATION, DECELERATION, OR SHOCK; INDICATING PRESENCE, ABSENCE, OR DIRECTION, OF MOVEMENT
    • G01P15/00—Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration
    • G01P15/02—Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration by making use of inertia forces using solid seismic masses
    • G01P15/08—Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration by making use of inertia forces using solid seismic masses with conversion into electric or magnetic values
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01P—MEASURING LINEAR OR ANGULAR SPEED, ACCELERATION, DECELERATION, OR SHOCK; INDICATING PRESENCE, ABSENCE, OR DIRECTION, OF MOVEMENT
    • G01P15/00—Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration
    • G01P15/02—Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration by making use of inertia forces using solid seismic masses
    • G01P15/08—Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration by making use of inertia forces using solid seismic masses with conversion into electric or magnetic values
    • G01P15/125—Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration by making use of inertia forces using solid seismic masses with conversion into electric or magnetic values by capacitive pick-up
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01P—MEASURING LINEAR OR ANGULAR SPEED, ACCELERATION, DECELERATION, OR SHOCK; INDICATING PRESENCE, ABSENCE, OR DIRECTION, OF MOVEMENT
    • G01P15/00—Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration
    • G01P15/02—Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration by making use of inertia forces using solid seismic masses
    • G01P15/08—Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration by making use of inertia forces using solid seismic masses with conversion into electric or magnetic values
    • G01P15/13—Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration by making use of inertia forces using solid seismic masses with conversion into electric or magnetic values by measuring the force required to restore a proofmass subjected to inertial forces to a null position

Definitions

  • the present invention relates to an inertial sensor, for example, an acceleration sensor that detects minute acceleration smaller than gravity.
  • Patent Document 1 describes a technology relating to a MEMS (Micro Electrical Mechanical Systems) sensor in which both an upper electrode and a lower electrode are patterned and both the upper electrode and the lower electrode vibrate. Yes.
  • the convex portion of the upper electrode functions as a stopper that prevents adhesion with the lower electrode
  • the convex portion on the silicon substrate functions as a stopper that prevents adhesion with the lower electrode.
  • Reflection seismic exploration is a geophone that generates a shock wave or continuous wave on the ground surface, and reflects the reflected waves that return from the ground reflecting surface (boundary surface where the acoustic impedance changes) back to the ground.
  • This is a method for exploring the depth distribution and underground structure of the subsurface reflecting surface by measuring and analyzing the above.
  • this reflection seismic exploration is widely used as the main exploration method for oil and natural gas.
  • an acceleration sensor that detects vibration acceleration far smaller than gravitational acceleration has attracted attention. In order to put such an acceleration sensor into practical use, it is desired to develop an acceleration sensor with low noise and very high sensitivity.
  • the acceleration sensor connects the mass body to the fixed portion via a resiliently deformable beam in the cavity, and detects the change in physical quantity due to the displacement of the mass body when acceleration is applied. Is detected.
  • the mass body functions as a movable electrode
  • the fixed electrode is disposed at a position facing the mass body.
  • the objective of this invention is providing the technique which can suppress the etching damage in the sticking of an inertial sensor, or the manufacturing process of an inertial sensor.
  • An inertial sensor includes a first movable electrode that is displaceable in a first direction, a plurality of first openings that pass through the first movable electrode, and a first movable electrode that is spaced apart from the first movable electrode in the first direction.
  • a plurality of first protections formed on opposing surfaces of the first fixed electrode disposed opposite to the first fixed electrode facing the first movable electrode and provided corresponding to each of the plurality of first openings.
  • each of the plurality of first protection portions includes a first opening corresponding to each of the plurality of first protection portions.
  • the inertial sensor manufacturing method includes (a) a step of forming a fixed electrode inside the groove of the base layer having the groove, (b) a step of forming a plurality of protective portions on the fixed electrode, (C) After the step (b), a step of bonding the MEMS layer on the base layer is provided. Then, (d) by patterning the MEMS layer, a fixed portion fixed to the base layer, a beam connected to the fixed portion, a mass that is suspended by the beam and functions as a movable electrode that can be displaced in the first direction. And a step of forming a plurality of openings penetrating the mass portion.
  • a cap layer connected to the fixing portion formed on the MEMS layer is formed on the MEMS layer, so that the mass portion formed on the MEMS layer is changed between the base layer and the cap layer.
  • the plurality of openings are formed so that each of the plurality of protection portions includes an opening corresponding to each of the plurality of protection portions in a plan view as viewed from the first direction. To do.
  • the reliability of the inertial sensor can be improved. Specifically, according to the inertial sensor in one embodiment, sticking can be suppressed. Moreover, according to the manufacturing method of the inertial sensor in one embodiment, etching damage can be suppressed.
  • FIG. 3 is a cross-sectional view showing a cross section of the acceleration sensor in the first embodiment.
  • 3 is a plan view showing a planar layout configuration of a base layer in Embodiment 1.
  • FIG. 3 is a plan view showing a planar layout configuration of a MEMS layer in the first embodiment.
  • FIG. 10 is a plan view showing an example of a planar layout configuration of a base layer in a second embodiment. It is a top view which shows the plane layout structural example (modification) of a base layer.
  • FIG. 10 is a plan view showing a planar layout configuration of a MEMS layer in a second embodiment. It is a top view which shows the example of a plane layout structure (modification) of a MEMS layer. It is a graph which shows the relationship between sealing pressure and mechanical noise.
  • FIG. 9 is a diagram showing a cross-sectional configuration of an acceleration sensor in a third embodiment.
  • FIG. 10 is a cross-sectional view showing a cross section of an acceleration sensor in a fourth embodiment.
  • FIG. 10 is a plan view showing a planar layout configuration of a base layer that constitutes a part of an acceleration sensor according to a fourth embodiment.
  • FIG. 10 is a plan view showing a planar layout configuration of a MEMS layer that constitutes a part of the acceleration sensor in the fourth embodiment. It is sectional drawing which shows the manufacturing process of the acceleration sensor in Embodiment 4.
  • FIG. 18 is a cross-sectional view showing a manufacturing process of the acceleration sensor following FIG. 17. It is sectional drawing which shows the manufacturing process of the acceleration sensor following FIG.
  • FIG. 20 is a cross-sectional view showing a manufacturing step of the acceleration sensor following FIG. 19.
  • the constituent elements are not necessarily indispensable unless otherwise specified and apparently essential in principle. Needless to say.
  • Acceleration sensors are used in a wide range of fields such as automobile attitude control, smartphones, and game machines.
  • the acceleration sensor used in these fields is small and can detect acceleration several times as large as gravity in a low frequency band of several hundred Hz or less.
  • the field of use of the acceleration sensor is not limited to the above-mentioned field, but has been expanded to a field for exploring underground resources.
  • reflection seismic wave exploration which is a kind of geophysical exploration, artificially generates a seismic wave and then receives a geophone (acceleration sensor) installed on the ground surface.
  • the reflected waves that bounce off the ground are captured and the results are analyzed to reveal the underground structure.
  • Fig. 1 is a schematic cross-sectional view of the earth's surface showing an outline of the reflection elastic wave exploration.
  • the excitation source VB installed on the ground surface GND to the ground
  • the elastic waves reflected by the boundary BUD1 and the boundary BUD2 of the plurality of formations are grounded.
  • Sensing is performed by an acceleration sensor (vibrator) AS installed in the vehicle. Since a general excitation source VB oscillates in a direction perpendicular to the ground surface, a P wave is efficiently excited in a direction close to the vertical direction. For this reason, the P wave is used in the reflection elastic wave exploration.
  • the acceleration sensor AS needs to detect the elastic vibration in the vertical direction.
  • the elastic wave excited in various directions propagates in the ground with large attenuation, reflects at the boundary BUD1 and boundary BUD2 of a plurality of formations, and propagates again in the ground with large attenuation. It spreads over a wide area and returns to the ground surface GND.
  • the acceleration sensor AS in order to detect weak elastic vibration, the acceleration sensor AS needs to be highly sensitive in the vertical direction. Specifically, since the acceleration of weak elastic vibration is smaller than the gravitational acceleration, the acceleration sensor used in the reflection elastic wave exploration is required to detect acceleration smaller than the gravitational acceleration with high sensitivity. .
  • the mass of the mass body that is a component of the acceleration sensor is increased, And the structure which makes a spring constant small and the structure which provides a some opening part in a mass body and reduces air resistance are employ
  • side effects occur as described in the section “Problems to be Solved by the Invention”. Therefore, in the first embodiment, a device that can suppress this side effect is taken. Below, the technical idea in this Embodiment 1 which gave this device is demonstrated.
  • FIG. 2 is a sectional view showing one section of the acceleration sensor AS1 in the first embodiment.
  • the acceleration sensor AS1 in the first embodiment has a base layer BL made of, for example, silicon (Si), and a fixed electrode FE made of, for example, a polysilicon film is formed on the base layer BL. ing.
  • a plurality of protection parts PU are formed on the surface of the fixed electrode FE so as to be separated from each other.
  • the plurality of protection units PU1 are formed of an insulating film typified by a silicon oxide film, for example.
  • a MEMS layer ML made of, for example, silicon is disposed above the base layer BL, and the MEMS layer ML is formed by processing the MEMS layer ML.
  • Part FU is formed.
  • the mass body MS is formed on the MEMS layer ML, and the mass body MS is disposed at a position facing the fixed electrode FE formed on the base layer BL.
  • the mass body MS is connected to the fixed portion FU via a beam (not shown). That is, the mass body MS is suspended by a beam and can be displaced in the z direction of FIG. For example, the mass body MS is displaced in the z direction when acceleration is applied in the z direction from the outside.
  • a plurality of openings OP penetrating the mass body MS are formed in the mass body MS.
  • the plurality of openings OP are provided so as to correspond to the plurality of protection units PU formed on the fixed electrode FE. That is, the protection part PU is provided so as to correspond to each of the plurality of openings OP.
  • the mass body MS is made of conductive silicon and can be displaced in the z direction, it also functions as the movable electrode VE. Therefore, in the acceleration sensor AS1 in the first embodiment, a capacitance is formed by the fixed electrode FE formed on the base layer BL and the mass body MS (movable electrode VE) formed on the MEMS layer ML. Will be.
  • a cap layer CL made of silicon is disposed on the MEMS layer ML.
  • the MEMS layer ML is sandwiched between the base layer BL and the cap layer CL in a cross-sectional view, and the mass body MS formed in the MEMS layer ML includes the base layer BL, the fixing unit FU, and the cap layer CL. It will be arrange
  • the acceleration sensor AS1 includes the movable electrode VE (mass body MS) that can be displaced in the z direction, the plurality of openings OP that penetrate the movable electrode VE, and the movable electrode in the z direction.
  • a plurality of protection portions formed on the opposing surfaces of the fixed electrode FE spaced apart from the VE and the fixed electrode FE facing the movable electrode VE, and provided corresponding to each of the plurality of openings OP.
  • Each of the PUs are the movable electrode VE (mass body MS) that can be displaced in the z direction, the plurality of openings OP that penetrate the movable electrode VE, and the movable electrode in the z direction.
  • the acceleration sensor AS1 includes a base layer BL, a cap layer CL disposed above the base layer BL, a cavity CAV sandwiched between the base layer BL and the cap layer CL, a cavity And a MEMS layer ML disposed in the part CAV.
  • the fixed electrode FE is formed on the base layer BL in the cavity CAV1.
  • the MEMS layer ML has a fixed portion FU fixed to the base layer BL and the cap layer CL, a beam connected to the fixed portion FU, and is suspended in the cavity CAV by the beam and functions as the movable electrode VE. Mass body MS to be formed.
  • FIG. 3 is a plan view showing a planar layout configuration of the base layer BL in the first embodiment.
  • a cross section taken along line AA in FIG. 3 corresponds to the base layer BL in FIG.
  • a cavity CAV is formed inside the base layer BL, and a fixed electrode FE is formed inside the cavity CAV.
  • a plurality of protection units PU are formed on the fixed electrode FE.
  • a plurality of protection parts PU spaced apart from each other are provided on the surface of the fixed electrode FE, and an uneven shape is formed on the surface of the fixed electrode FE.
  • FIG. 4 is a plan view showing a planar layout configuration of the MEMS layer ML in the first embodiment.
  • a cross section taken along line AA in FIG. 4 corresponds to the MEMS layer ML in FIG.
  • a cavity CAV is formed inside the MEMS layer ML.
  • a fixed part FU Inside the cavity CAV, a fixed part FU, a beam BM connected to the fixed part FU, and the beam BM
  • a mass body MS to be connected is formed. That is, in the MEMS layer ML, the mass body MS is connected to the fixed portion FU via the beam BM, and the mass portion MS is suspended by the beam BM.
  • a plurality of openings OP are formed in the mass body MS.
  • each planar size of the plurality of protection units PU corresponds to each of the plurality of protection units PU.
  • the opening size OP is larger than the planar size.
  • each of the plurality of protection units PU is formed so as to include the opening OP corresponding to each of the plurality of protection units PU.
  • the acceleration sensor AS1 is an acceleration sensor that captures acceleration applied in the z direction as a change in capacitance of a variable capacitor including the movable electrode VE and the fixed electrode FE.
  • the acceleration sensor AS1 is an acceleration sensor that captures acceleration applied in the z direction as a change in capacitance of a variable capacitor including the movable electrode VE and the fixed electrode FE.
  • it is possible to detect acceleration by detecting a change in capacitance due to acceleration due to acceleration without applying a modulation signal.
  • the detection signal based on the capacitance change in the variable capacitance corresponding to the acceleration is a low-frequency signal, it is easily affected by 1 / f noise.
  • a modulation signal is used.
  • the detection signal based on the capacitance change in the variable capacitor corresponding to the acceleration is modulated by the modulation signal to become a high frequency signal, it is difficult to receive 1 / f noise. That is, since the 1 / f noise is smaller in the high-frequency signal than in the low-frequency signal, the S / N ratio can be improved. As a result, the detection sensitivity of the acceleration sensor AS1 can be improved. For this reason, in the first embodiment, first, a modulation signal is applied to a variable capacitor composed of the movable electrode VE and the fixed electrode FE.
  • the mass body MS is displaced in the z direction.
  • a change in the capacitance of the variable capacitor including the movable electrode VE (mass body MS) and the fixed electrode FE occurs.
  • This capacitance change is added to the modulation signal and output to the signal processing circuit.
  • a modulation signal to which a capacitance change due to acceleration is added is input to the CV conversion unit, and the capacitance change is converted into an analog voltage signal.
  • the converted analog voltage signal is converted into a digital voltage signal by the AD converter.
  • the demodulated signal is extracted by the synchronous detector.
  • the demodulated signal demodulated by the synchronous detection section passes through an LPF (low frequency band pass filter), and finally an acceleration signal (detection signal) corresponding to the acceleration is output from the output terminal.
  • LPF low frequency band pass filter
  • FIG. 5 is an enlarged view of a part of FIG.
  • the feature point in the first embodiment is that each of the plurality of protection units PU corresponds to each of the plurality of protection units PU in a plan view viewed from the z direction.
  • the point is to include the opening OP (see FIGS. 3 and 4). Reflecting this feature point, in FIG.
  • the width L1 in the x direction of the protection part PU is larger than the opening dimension L3 in the x direction of the opening OP, and the protection part PU
  • the non-overlapping region NOR that does not overlap with the opening OP is formed.
  • the first advantage in the first embodiment is that the mass body MS can be prevented from sticking to the fixed electrode FE.
  • the acceleration sensor AS1 in the first embodiment has a configuration in which the mass of the mass body MS is increased and the spring constant of the beam is decreased in order to realize a highly sensitive acceleration sensor.
  • the mass body MS is greatly displaced and comes into contact with the fixed electrode FE, sticking is likely to occur.
  • the surface of the fixed electrode FE is flat, when the mass body MS comes into contact with the fixed electrode FE, the contact area increases, and thus sticking is likely to occur.
  • the mass body MS does not return to the original position, and the acceleration sensor AS1 does not operate normally. That is, since sticking causes a decrease in the reliability of the acceleration sensor AS1, it is necessary to suppress the sticking from the viewpoint of improving the reliability of the acceleration sensor AS1.
  • the surface of the fixed electrode FE has an uneven shape. It is formed. Therefore, even when the mass body MS is in contact with the fixed electrode FE due to excessive displacement of the mass body MS, since the uneven shape is formed on the surface of the fixed electrode FE, the protection unit PU and the mass body MS The contact area becomes smaller and sticking is less likely to occur. This means that a reduction in reliability of the acceleration sensor AS1 due to sticking can be suppressed.
  • the reliability of acceleration sensor AS1 can be improved.
  • each of the plurality of protection units PU is provided corresponding to the opening OP1. Therefore, even if the mass body MS is displaced in the z direction so as to contact the fixed electrode FE, the mass body MS does not contact the entire width L3 of the protection portion PU, but instead of the protection portion PU and the opening OP. The contact is made within the range of the width L2 of the non-overlapping region NOR. This means that the contact area between the mass body MS and the protection part PU can be reduced.
  • the plurality of protection portions PU are provided on the surface of the fixed electrode FE so as to be separated from each other, and as a result, an uneven shape is formed on the surface of the fixed electrode FE.
  • Each of the plurality of protection units PU is provided so as to include the corresponding opening OP. As a result, the contact area between the mass body MS and the protection part PU is reduced due to the formation of an uneven shape on the surface of the fixed electrode FE, and each of the protection parts PU has a corresponding opening.
  • the length L2 in the x direction of the non-overlapping region NOR between each of the plurality of protection units PU and the opening OP corresponding to each of the plurality of protection units PU is equal to the plurality of protection units PU.
  • the protection part PU and the opening OP provided corresponding to the protection part PU when attention is paid to the protection part PU and the opening OP provided corresponding to the protection part PU, one end of the protection part PU from one end of the opening OP in the x direction in a plan view seen from the z direction.
  • the distance (L2) to the portion can be made smaller than the opening dimension L3 of the opening OP in the x direction.
  • the second advantage of the feature point in the first embodiment is an advantage in the manufacturing process.
  • the mass body MS and the opening OP penetrating the mass body MS are formed by patterning the MEMS layer ML, and this patterning step includes a step of dry etching the MEMS layer ML.
  • the fixed portion FU, the beam, the mass body MS, and the plurality of openings OP are formed by etching the MEMS layer ML.
  • these components are included in the MEMS layer ML.
  • regions having different opening areas are etched at the same time.
  • the etching time is determined in accordance with the opening OP having the smallest opening area. Furthermore, even in the wafer plane, the etching rate is different between the central portion and the peripheral portion of the wafer, so the etching time is set to be longer than the etching time necessary for the penetration of the MEMS layer ML. Therefore, overetching is performed. However, if over-etching is performed, the fixed electrode FE disposed below the MEMS layer ML is etched, and the fixed electrode FE may be damaged.
  • each of the plurality of protection units PU includes an opening OP corresponding to each of the plurality of protection units PU.
  • the protection unit PU covers the region. Therefore, the fixed electrode FE can be protected from over-etching within a necessary and sufficient range. This is the second advantage brought about by the feature points in the first embodiment. As described above, according to the first embodiment, it is possible to protect the fixed electrode FE from etching damage, thereby improving the reliability of the acceleration sensor AS1.
  • the width L2 of the non-overlapping region NOR shown in FIG. 5 becomes larger, the fixed electrode FE can be protected from side etching. From the viewpoint of reducing etching damage to the fixed electrode FE, the non-overlapping region is as much as possible. It would be desirable to increase the NOR width L2. Therefore, the requirement for the width L2 of the non-overlapping region NOR is contradictory between the case where attention is paid to the viewpoint of suppressing sticking and the case where attention is paid to the viewpoint of suppressing etching damage. As a realistic response in this regard, it is within a well-balanced range so that it is within a reasonable range from the viewpoint of suppressing sticking and within a reasonable range from the viewpoint of suppressing etching damage. It is desirable to set the width L2 of the non-overlapping area NOR.
  • the mass of the mass body MS of the acceleration sensor AS1 is increased in order to detect an acceleration smaller than the gravitational acceleration with high sensitivity without considering side effects.
  • the mass body MS can be provided with a plurality of openings OP. That is, according to the feature point in the first embodiment, the detection sensitivity of the acceleration sensor AS1 can be improved while effectively suppressing the side effect of the mass body MS sticking and the etching damage to the fixed electrode FE. An excellent effect can be obtained.
  • FIG. 6 is a plan view showing a planar layout configuration example of the base layer BL in the second embodiment.
  • a fixed electrode FE, a servo electrode SE1, and a servo electrode SE2 are formed in the base layer BL.
  • the servo electrode SE1, the fixed electrode FE, and the servo electrode SE2 are arranged so as to be aligned in the y direction, and the fixed electrode is sandwiched between the servo electrode SE1 and the servo electrode SE2 in plan view.
  • FE is arranged.
  • a plurality of protection parts PU are formed on the fixed electrode FE, and a plurality of protection parts PU are also formed on the servo electrodes SE1 and SE2.
  • the feature point that the plurality of protection parts PU spaced apart from each other is provided on the surface of the fixed electrode FE and the uneven shape is provided on the surface of the fixed electrode FE is realized.
  • not only the fixed electrode FE but also the servo electrode SE1 and the servo electrode SE2 are provided with a plurality of protective portions PU spaced from each other on the surfaces of the servo electrode SE1 and the servo electrode SE2, and the servo electrode Concave and convex shapes are provided on the surfaces of SE1 and servo electrode SE2. For this reason, the above-described feature points are also realized in the servo electrode SE1 and the servo electrode SE2.
  • the servo electrode SE1 and the servo electrode SE2 are formed on the base layer BL shown in FIG.
  • the base layer BL shown in FIG. 6 is formed of the same layer as the fixed electrode FE, and is disposed above the base layer BL in the z direction (upward direction in FIG. 6) (illustrated).
  • the servo electrode SE1 and the servo electrode SE2 that are arranged opposite to each other and generate an electrostatic force that cancels the displacement of the mass body in the z direction are formed.
  • a servo voltage is applied to the servo electrode SE1 and the servo electrode SE2, and the acceleration is caused by the Coulomb force (electrostatic force) generated by applying the servo voltage to the servo electrode SE1 and the servo electrode SE2.
  • the displacement in the z direction of the mass body based thereon is cancelled.
  • the mass body is hardly displaced in the z direction, but the servo electrode SE1 and the servo electrode SE2 have a servo voltage proportional to the magnitude of the acceleration.
  • this servo voltage it is possible to detect the acceleration applied to the acceleration sensor according to the second embodiment.
  • the advantage of providing the servo electrode SE1 and the servo electrode SE2 is that acceleration can be detected without displacing the mass body in the z direction. That is, by providing a servo mechanism, when a large acceleration is applied to the acceleration sensor, it is possible to prevent the mass body from contacting the fixed electrode FE due to an unexpected displacement of the mass body.
  • the mass body and the fixed electrode FE can be prevented by the servo mechanism as well as the anti-sticking effect due to the feature point in the first embodiment described above.
  • an anti-sticking effect can be obtained.
  • the configuration in which the servo electrode SE1 and the servo electrode SE2 are provided in the acceleration sensor has an effect of enhancing the effect of preventing sticking, and is a useful configuration from the viewpoint of suppressing the sticking and improving the reliability of the acceleration sensor. Recognize.
  • the servo mechanism works in the operating state of the acceleration sensor, it is possible to obtain the anti-sticking effect caused by the feature points in the first embodiment and the anti-sticking effect caused by the servo mechanism.
  • the servo mechanism does not work, so that it is not possible to obtain an anti-sticking effect caused by the servo mechanism.
  • the mass body will be displaced.
  • the servo mechanism Since it does not work, sticking may occur.
  • the effect of preventing sticking caused by the feature point in the first embodiment described above can be obtained. That is, the configuration in which the concavo-convex shape is provided by the plurality of protection units PU exists regardless of the operation state or non-operation state of the acceleration sensor. Therefore, even in the acceleration sensor according to the second embodiment, an effect of preventing sticking can be obtained not only when the acceleration sensor is in the operating state but also when the acceleration sensor is in the non-operating state. That is, unlike the servo mechanism, the feature point in the first embodiment described above is excellent in that an effect of preventing sticking can be obtained regardless of whether the acceleration sensor is in an operating state or a non-operating state. It can be said that
  • the wiring WL is drawn from the fixed electrode FE.
  • the wiring WL1 is drawn from the servo electrode SE1
  • the wiring WL2 is drawn from the servo electrode SE2.
  • a wiring protection unit WPU that covers a part of the wiring WL and a part of the wiring WL1 is formed.
  • a wiring protection part WPU that covers a part of the wiring WL and a part of the wiring WL2 is formed.
  • the wiring protection unit WPU is formed in the same layer as the plurality of protection units PU, and has a function of protecting the wiring WL, the wiring WL1, and the wiring WL2 from etching damage when the MEMS layer is etched. .
  • a through-hole penetrating the MEMS layer ML is also formed. Therefore, a part of the wiring may be arranged on the base layer BL below the MEMS layer ML so as to overlap the through hole in a plan view. In this case, a portion of the wiring that overlaps with the through hole in a plane is damaged by etching when the through hole is formed.
  • the wiring protection portion WPU is formed across a part of the wiring WL and the part of the wiring WL1 that overlaps the through-hole in a plan view
  • a wiring protection part WPU is formed across a part of the wiring WL and a part of the wiring WL2 overlapping each other.
  • the wiring protection part WPU is formed so as to include the through hole in a plan view.
  • FIG. 7 is a plan view showing a planar layout configuration example of the base layer BL.
  • a rectangular fixed electrode FE is formed on the base layer BL, and this fixed electrode FE also functions as a servo electrode SE. That is, in the planar layout configuration example of the base layer BL shown in FIG. 7, a configuration in which the fixed electrode FE also serves as the servo electrode SE is shown. In this case, the detection operation by the fixed electrode FE and the servo operation by the servo electrode SE are performed in a time division manner.
  • the planar layout configuration of the base layer BL can employ not only the planar layout configuration shown in FIG. 6 but also the planar layout configuration shown in FIG.
  • FIG. 8 is a plan view showing a planar layout configuration example of the base layer BL.
  • the fixed electrode FE and the servo electrode SE1 are separately formed on the base layer BL.
  • the fixed electrode FE and the servo electrode SE1 are arranged so as to be aligned in the x direction.
  • the planar layout configuration of the base layer BL can employ not only the planar layout configuration shown in FIGS. 6 and 7, but also the planar layout configuration shown in FIG.
  • FIG. 9 is a plan view illustrating a planar layout configuration example of the base layer BL.
  • the fixed electrode FE and the servo electrode SE1 are separately formed on the base layer BL.
  • the fixed electrode FE and the servo electrode SE1 are arranged so as to be aligned in the y direction.
  • the planar layout configuration of the base layer BL can employ not only the planar layout configuration shown in FIGS. 6 to 8, but also the planar layout configuration shown in FIG.
  • FIG. 10 is a plan view showing a planar layout configuration of the MEMS layer ML in the second embodiment.
  • the MEMS layer ML has a rectangular shape.
  • a fixed portion FU Inside the MEMS layer ML, a fixed portion FU, a beam BM connected to the fixed portion FU, and a mass body MS connected to the beam BM. And are formed. That is, in the MEMS layer ML, the mass body MS is connected to the fixed portion FU via the beam BM, and the mass portion MS is suspended by the beam BM.
  • a plurality of openings OP are formed.
  • the planar shape of each of the plurality of openings OP is a slit shape SL.
  • each of the plurality of protection units PU is formed so as to include an opening OP corresponding to each of the plurality of protection units PU. It can be seen that the feature points in 1 are realized.
  • FIG. 11 is a plan view illustrating a planar layout configuration example of the MEMS layer ML.
  • the mass body MS connected to the fixed portion FU via the beam BM is formed in the MEMS layer ML, and a plurality of openings are formed in the mass body MS so as to penetrate the mass body MS.
  • OP is formed.
  • the planar shape of each of the plurality of openings OP is a hole shape HL.
  • the planar layout configuration of the MEMS layer ML can adopt not only the planar layout configuration shown in FIG. 10 but also the planar layout configuration shown in FIG.
  • the mass body MS is provided with a plurality of openings OP to reduce the air resistance, and the mass body MS is sufficiently more than the atmospheric pressure. Sealed with low pressure. Thereby, mechanical noise can also be reduced in the second embodiment.
  • FIG. 12 is a graph showing the relationship between sealing pressure and mechanical noise.
  • the horizontal axis represents the sealing pressure (Pa)
  • the vertical axis represents the mechanical noise (ng / ⁇ Hz).
  • FIG. 12 corresponds to a graph corresponding to a configuration in which no opening is provided in the mass body ((a) no hole) and a configuration in which a rough slit-like opening is provided in the mass ((b) rough slit).
  • the configuration corresponding to the configuration in which the mass body is provided with a dense slit-shaped opening ((c) slit dense), and the configuration in which the mass body is provided with a hole-shaped opening ((d) hole) The graph is shown. As shown in FIG.
  • the mechanical noise decreases as the sealing pressure decreases. It can also be seen that the mechanical noise varies depending on the shape of the opening provided in the mass body. For example, when there is no opening, the mechanical noise is about 200 (ng / ⁇ Hz) when the sealing pressure is 1 (Pa), while when the opening is present, the sealing pressure is 1 (Pa). It can be seen that the mechanical noise is about 20 (ng / ⁇ Hz). Therefore, not only in the first embodiment but also in the second embodiment, the mass body MS is provided with a plurality of openings OP, and the mass body MS is sealed at a pressure sufficiently lower than the atmospheric pressure.
  • the acceleration detection sensitivity can be improved not only in the first embodiment but also in the second embodiment. That is, also in the second embodiment, the acceleration detection sensitivity can be improved without incurring the side effect of sticking the mass body MS and etching damage to the fixed electrode FE.
  • FIG. 13 is a diagram illustrating a cross-sectional configuration of the acceleration sensor AS1 according to the third embodiment, and corresponds to FIG. 2 illustrating the first embodiment.
  • a fixed electrode FE1 is formed on the base layer BL, and a plurality of protective portions PU1 are formed on the fixed electrode FE1.
  • each of the plurality of protection parts PU1 is formed so as to include the opening OP corresponding to each of the plurality of protection parts PU1.
  • the fixed electrode FE3 is formed on the lower surface of the cap layer CL, and the fixed surface of the fixed electrode FE3 facing the mass body MS is formed on the opposite surface.
  • Each of the plurality of protection units PU3 corresponding to each of the plurality of openings OP is formed. And in the planar view seen from z direction, each of several protection part PU3 is formed so that the opening part OP corresponding to each of several protection part PU3 may be included.
  • the contact area between the mass body MS and the protection unit PU3 is reduced due to the formation of the uneven shape on the surface of the fixed electrode FE3, and a plurality of protections.
  • Each of the parts PU3 is provided so as to include the corresponding opening OP.
  • the fixed electrode FE1 provided in the base layer BL not only suppression of sticking but also etching damage in the step of dry etching the MEMS layer ML disposed above the base layer BL may be received. It is necessary to design a plurality of protection units PU1 in consideration.
  • the fixed electrode FE3 provided in the cap layer CL is joined to the MEMS layer ML together with the cap layer CL after forming the MEMS layer ML. Therefore, it is not necessary to consider etching damage in the fixed electrode FE3. That is, the plurality of protection portions PU3 formed on the fixed electrode FE3 provided in the cap layer CL can be designed from the viewpoint of suppressing sticking without considering etching damage.
  • each of the plurality of protection units PU3 is formed so as to include an opening OP corresponding to each of the plurality of protection units PU3 in a plan view viewed from the z direction. It is only necessary to reduce the planar size of the plurality of protection units PU3 as much as possible within the range of this condition. This is because, according to this configuration, even if an unexpected large displacement occurs in the mass body MS, the contact area between the fixed electrode FE3 (specifically, the protection unit PU3) provided in the cap layer CL and the mass body MS. This is because sticking can be effectively suppressed as a result.
  • the acceleration sensor AS1 according to the third embodiment includes a first variable capacitor including a fixed electrode FE1 and a mass body MS, and a second variable capacitor including a fixed electrode FE3 and the mass body MS. Yes.
  • the capacitance change of the first variable capacitor and the capacitance change of the second variable capacitor when the acceleration in the z direction is applied have opposite characteristics. That is, when the capacitance of the first variable capacitor increases, the capacitance of the second variable capacitor decreases, while when the capacitance of the first variable capacitor decreases, the capacitance of the second variable capacitor decreases. To increase.
  • the acceleration sensor AS1 in the third embodiment the following advantages can be obtained.
  • a first variable capacitor and a second variable capacitor are connected in series between a first input terminal and a second input terminal, and CV conversion is performed at a connection portion (connection node) between the first variable capacitor and the second variable capacitor.
  • connection portion connection node
  • opposite-phase modulation signals having a phase difference of 180 ° are applied to the first input terminal and the second input terminal, respectively.
  • the capacitance of the first variable capacitance when no acceleration is applied is “C”
  • the capacitance of the second variable capacitance when no acceleration is applied is “C”. C ".
  • the mass body MS is common to the first variable capacitor and the second variable capacitor, and the distance between the mass body MS and the fixed electrode FE1 and the mass body MS are fixed. This is because the distance from the electrode FE3 can be made equal, and the plane size of the fixed electrode FE1 and the plane size of the fixed electrode FE3 can be designed to be equal.
  • the capacitance of the first variable capacitance increases to “C + ⁇ C”, while the capacitance of the second variable capacitance decreases to “C ⁇ C”.
  • the capacitance “C” of the first variable capacitor and the capacitance of the second variable capacitor are set to “ “C” is canceled, and the charge transfer amount includes only the component of the capacitance change 2 ⁇ C caused by the acceleration.
  • the signal includes only the component of capacitance change (2 ⁇ C) caused by acceleration.
  • FIG. 14 is a cross-sectional view showing one cross section of the acceleration sensor AS2 in the fourth embodiment.
  • the fixed electrode FE1 and the fixed electrode FE2 are disposed on the base layer BL so as to be spaced apart from each other.
  • a plurality of protection portions PU1 are formed on the surface of the fixed electrode FE1 so as to be separated from each other, and a plurality of protection portions PU2 are also formed on the surface of the fixed electrode FE2 so as to be separated from each other.
  • the MEMS layer ML is disposed above the base layer BL.
  • the MEMS layer ML has a fixed portion FU formed by processing the MEMS layer ML, and the MEMS layer ML is located above the base layer BL by bonding the fixed portion FU and the base layer BL. Will be placed.
  • the mass body MS1 is formed in the MEMS layer ML, and the mass body MS1 is disposed at a position facing the fixed electrode FE1 formed in the base layer BL.
  • the mass body MS2 is formed in the MEMS layer ML, and the mass body MS2 is disposed at a position facing the fixed electrode FE2 formed in the base layer BL.
  • the mass body MS1 and the mass body MS2 are connected to the fixed portion FU via a beam (not shown). That is, each of mass body MS1 and mass body MS2 is suspended by the beam.
  • a plurality of openings OP1 penetrating the mass body MS1 are formed in the mass body MS1.
  • the plurality of openings OP1 are provided so as to correspond to the plurality of protection units PU1 formed on the fixed electrode FE1. That is, the protection part PU1 is provided so as to correspond to each of the plurality of openings OP1.
  • a plurality of openings OP2 penetrating the mass body MS2 are formed in the mass body MS2, as shown in FIG.
  • the plurality of openings OP2 are provided so as to correspond to the plurality of protection units PU2 formed on the fixed electrode FE2. That is, the protection part PU2 is provided so as to correspond to each of the plurality of openings OP2.
  • the mass body MS1 also functions as the movable electrode VE1. That is, in the acceleration sensor AS2 in the fourth embodiment, a capacitance is formed by the fixed electrode FE1 formed on the base layer BL and the mass body MS1 (movable electrode VE1) formed on the MEMS layer ML. Will be. Similarly, the mass body MS2 also functions as the movable electrode VE2. That is, in the acceleration sensor AS2 in the fourth embodiment, a capacitance is formed by the fixed electrode FE2 formed on the base layer BL and the mass body MS2 (movable electrode VE2) formed on the MEMS layer ML. Will be.
  • the cap layer CL is disposed on the MEMS layer ML.
  • the MEMS layer ML is sandwiched between the base layer BL and the cap layer CL in a cross-sectional view, and the mass body MS1 formed in the MEMS layer ML includes the base layer BL, the fixed portion FU, and the cap layer CL. It is arrange
  • the mass body MS2 formed in the MEMS layer ML is disposed inside the cavity CAV2 surrounded by the base layer BL, the fixing part FU, and the cap layer CL.
  • the inside of the cavity CAV1 and the cavity CAV2 is filled with gas, and the pressure inside the cavity CAV1 and the cavity CAV2 is, for example, a pressure sufficiently lower than the atmospheric pressure.
  • each plane size of the plurality of openings OP1 is smaller than each plane size of the plurality of openings OP2, and each plane size of the plurality of protection units PU1 is equal to the plurality of protection units PU2. It is smaller than each plane size.
  • a mass difference is generated between the mass body MS1 and the mass body MS2.
  • the acceleration sensor AS2 in the fourth embodiment performs a “seesaw operation”.
  • each of the plurality of protection units PU1 includes an opening OP corresponding to each of the plurality of protection units PU in a plan view viewed from the z direction
  • Each of the protection parts PU2 includes an opening OP2 corresponding to each of the plurality of protection parts PU2.
  • the mass of the mass body MS1 and the mass of the mass body MS2 of the acceleration sensor AS2 are detected with high sensitivity in order to detect an acceleration smaller than the gravitational acceleration without considering side effects. And the spring constant of the beam can be reduced. Furthermore, in order to reduce mechanical noise, the mass body MS1 can be provided with a plurality of openings OP1, and the mass body MS2 can be provided with a plurality of openings OP2. That is, also in the fourth embodiment, it is possible to obtain an excellent effect that the detection sensitivity of the acceleration sensor AS2 can be improved while effectively suppressing the side effects of sticking and etching damage.
  • the acceleration sensor AS2 in the fourth embodiment includes a first variable capacitor composed of a fixed electrode FE1 and a mass body MS1, and a second variable capacitor composed of a fixed electrode FE2 and a mass body MS2. Yes.
  • the acceleration sensor AS2 in the fourth embodiment has a “seesaw structure”, and the capacitance change of the first variable capacitor and the capacitance change of the second variable capacitor when the acceleration in the z direction is applied are reversed. It becomes a characteristic. That is, when the capacitance of the first variable capacitor increases, the capacitance of the second variable capacitor decreases, while when the capacitance of the first variable capacitor decreases, the capacitance of the second variable capacitor decreases. To increase. As a result, according to the acceleration sensor AS2 in the fourth embodiment, the following advantages can be obtained.
  • a first variable capacitor and a second variable capacitor are connected in series between a first input terminal and a second input terminal, and CV conversion is performed at a connection portion (connection node) between the first variable capacitor and the second variable capacitor.
  • connection portion connection node
  • opposite-phase modulation signals having a phase difference of 180 ° are applied to the first input terminal and the second input terminal, respectively.
  • the capacitance of the first variable capacitor when no acceleration is applied is “C1”
  • the capacitance of the second variable capacitor when no acceleration is applied is “C2”.
  • the capacitance of the first variable capacitor increases to “C1 + ⁇ C1,” while the capacitance of the second variable capacitor decreases to “C2 ⁇ C2.”
  • the capacitance “C1” of the first variable capacitor and the capacitance of the second variable capacitor are expressed as “
  • the ratio of the component of the capacitance change ( ⁇ C1 + ⁇ C2) caused by the acceleration is increased in the charge transfer amount.
  • the influence of the capacitance “C1” and the capacitance “C2” unrelated to the capacitance change ( ⁇ C1 + ⁇ C2) due to acceleration is reduced in the amount of charge transfer (becomes C1-C2).
  • the component of capacitance change ( ⁇ C1 + ⁇ C2) caused by the acceleration included in the signal can be increased.
  • FIG. 15 is a plan view showing a planar layout configuration of the base layer BL constituting a part of the acceleration sensor according to the fourth embodiment.
  • a section taken along line AA in FIG. 15 corresponds to the base layer BL in FIG.
  • the base layer BL has a rectangular shape, and a fixed portion FU is formed at the center of the base layer BL.
  • a fixed electrode FE1, a servo electrode SE1A, and a servo electrode SE2A are formed in the left region from the center of the base layer BL. Specifically, as shown in FIG.
  • the servo electrode SE1A, the fixed electrode FE1, and the servo electrode SE2A are arranged so as to be aligned in the y direction, and are arranged on the servo electrode SE1A and the servo electrode SE2A in a plan view.
  • the fixed electrode FE1 is disposed so as to be sandwiched.
  • a plurality of protection portions PU1 are formed on the fixed electrode FE1, and a plurality of protection portions PU1 are also formed on the servo electrode SE1A and the servo electrode SE2A.
  • a plurality of protection portions PU1 that are spaced apart from each other are provided on the surfaces of the servo electrode SE1A and the servo electrode SE2A.
  • Concave and convex shapes are provided on the surfaces of SE1A and servo electrode SE2A. For this reason, the above-described feature points are also realized in the servo electrode SE1A and the servo electrode SE2A.
  • a fixed electrode FE2, a servo electrode SE1B, and a servo electrode SE2B are formed in a region on the right side from the center of the base layer BL. Specifically, as shown in FIG. 15, the servo electrode SE1B, the fixed electrode FE2, and the servo electrode SE2B are arranged so as to be aligned in the y direction, and the servo electrode SE1B and the servo electrode SE2B are arranged in a plan view.
  • the fixed electrode FE2 is disposed so as to be sandwiched.
  • a plurality of protection portions PU2 are formed on the fixed electrode FE2, and a plurality of protection portions PU2 are also formed on the servo electrode SE1B and the servo electrode SE2B.
  • the feature point that the plurality of protection parts PU2 spaced apart from each other is provided on the surface of the fixed electrode FE2, and the uneven shape is provided on the surface of the fixed electrode FE2.
  • a plurality of protection portions PU2 that are spaced apart from each other are provided on the surfaces of the servo electrode SE1B and the servo electrode SE2B. Concave and convex shapes are provided on the surfaces of SE1B and servo electrode SE2B. For this reason, the above-described feature points are also realized in the servo electrode SE1B and the servo electrode SE2B.
  • the respective planar sizes of the plurality of protection units PU1 are smaller than the respective plane sizes of the plurality of protection units PU2.
  • the base layer BL in the fourth embodiment has a planar layout configuration.
  • FIG. 16 is a plan view showing a planar layout configuration of the MEMS layer ML that constitutes a part of the acceleration sensor according to the fourth embodiment.
  • a section taken along line AA in FIG. 16 corresponds to the MEMS layer ML in FIG.
  • the MEMS layer ML has a rectangular shape, and a fixed portion FU and a beam BM are formed at the center of the MEMS layer ML.
  • a mass body MS1 suspended from the beam BM is formed in the left area of the central portion, and a mass body MS2 suspended from the beam BM is formed in the right area of the central portion.
  • each planar size of the plurality of openings OP1 is smaller than each planar size of the plurality of openings OP2.
  • each of the plurality of protection units PU1 corresponds to each of the plurality of protection units PU1. It is larger than the planar size of the opening OP1.
  • each of the plurality of protection units PU1 is formed so as to include an opening OP1 corresponding to each of the plurality of protection units PU1.
  • each of the plurality of protection units PU2 is larger than the plane size of the opening OP2 corresponding to each of the plurality of protection units PU2.
  • each of the plurality of protection units PU2 is formed so as to include an opening OP2 corresponding to each of the plurality of protection units PU2.
  • the MEMS layer ML according to the fourth embodiment has a planar layout configuration.
  • the acceleration sensor according to the fourth embodiment is configured as described above, and the manufacturing method thereof will be described below with reference to the drawings.
  • a base layer BL made of a silicon wafer (semiconductor substrate) is prepared. Then, a pair of grooves DIT is formed on the surface of the base layer BL by using a photolithography technique and an etching technique. Subsequently, after a polysilicon film is formed on each bottom surface of the pair of grooves DIT, the fixed electrode FE1 is formed on the bottom surface of one groove DIT by using a photolithography technique and an etching technique, and the other groove A fixed electrode FE2 is formed on the bottom surface of the DIT.
  • an insulating film made of, for example, a silicon oxide film is formed on the surface of the fixed electrode FE1 and the surface of the fixed electrode FE2.
  • a plurality of island-shaped protective portions PU1 are formed on the surface of the fixed electrode FE1
  • a plurality of island-shaped protective portions PU2 are formed on the surface of the fixed electrode FE2 by using a photolithography technique and an etching technique.
  • a plurality of protection parts PU1 spaced apart from each other are formed on the surface of the fixed electrode FE1
  • a plurality of protection parts PU2 spaced apart from each other are formed on the surface of the fixed electrode FE2.
  • the protection unit PU1 and the protection unit PU2 are formed so that the respective planar sizes of the plurality of protection units PU1 are smaller than the respective plane sizes of the plurality of protection units PU2.
  • the MEMS layer (MEMS substrate) ML made of, for example, silicon is disposed on the surface of the base layer BL, and the base layer BL and the MEMS layer ML are formed by using a wafer bonding technique. And join. Thereafter, the surface of the MEMS layer ML is polished. Specifically, for example, polishing is performed so that the thickness of the MEMS layer ML is about 250 ⁇ m.
  • the MEMS layer ML is patterned by using a photolithography technique and a dry etching technique. Accordingly, a fixed portion FU fixed to the base layer BL, a beam (not shown) connected to the fixed portion FU, a mass portion MS1 that functions as a movable electrode that is suspended by the beam and is displaceable in the z-direction. A mass body MS2 is formed. In particular, the mass body MS1 is formed to face the fixed electrode FE1 formed on the base layer BL, and the mass body MS2 is formed to face the fixed electrode FE2 formed on the base layer BL. .
  • a plurality of openings OP1 penetrating the mass body MS1 and a plurality of openings OP2 penetrating the mass body MS2 are formed.
  • the planar size of the opening OP1 is smaller than the planar size of the opening OP2.
  • the mass of mass body MS1 can be made larger than the mass of mass body MS2.
  • the etching rate of the opening OP1 and the etching rate of the opening OP2 are different. Specifically, the etching rate of the opening OP1 having a small planar size is slower than the etching rate of the opening OP2 having a large planar size. Furthermore, since there is a distribution in the etching rate even within the wafer surface, over-etching is performed so as not to cause insufficient etching.
  • each of the plurality of protection units PU1 includes an opening OP1 corresponding to each of the plurality of protection units PU1, and each of the plurality of protection units PU2 includes a plurality of protection units PU2.
  • An opening OP2 corresponding to each of the protective parts PU2 is included.
  • the fixing unit FU formed on the MEMS layer ML and the cap layer CL are joined on the MEMS layer ML. Accordingly, the mass body MS1 formed in the MEMS layer ML is sealed in the cavity CAV1 sandwiched between the base layer BL and the cap layer CL, and the mass body MS2 formed in the MEMS layer ML is sealed with the base layer BL. It can be sealed in the cavity CAV2 sandwiched between the cap layers CL. At this time, the inside of the cavity part CAV1 and the inside of the cavity part CAV2 are sealed with a pressure sufficiently lower than the atmospheric pressure, for example. As described above, the acceleration sensor according to the fourth embodiment can be manufactured.
  • the method for manufacturing the acceleration sensor AS1 is not described.
  • the method for manufacturing the acceleration sensor AS2 is described.
  • the acceleration sensor AS1 in the first embodiment can be manufactured through substantially the same process as the manufacturing process described in the fourth embodiment.
  • an acceleration sensor has been described as an example of the inertial sensor.
  • the technical idea in the above-described embodiment is that the mass body is restrained from sticking between the fixed body and the mass body, and there are a plurality of mass sensors. This is made from the viewpoint of suppressing etching damage to the fixed electrode when the openings are provided. Therefore, any inertial sensor having a mass body and a fixed electrode and having a configuration in which a plurality of openings are formed in the mass body can be widely applied.
  • a configuration in which a mass body and a fixed electrode are provided and a plurality of openings are formed in the mass body may be employed. In addition, it can be widely applied to angular velocity sensors.

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Abstract

La présente invention concerne une technologie permettant que l'adhérence d'un capteur inertiel et un dommage de gravure du capteur inertiel dans des étapes de fabrication puissent être supprimés. Spécifiquement, dans une vue plane depuis la direction z, chacun d'une pluralité d'unités de protection PU comprend une ouverture OP correspondant à chacune des unités de protection PU. De manière à refléter la configuration, par exemple, la largeur L1 des unités de protection PU, ladite largeur étant dans la direction x, est définie de manière à être plus grande que la dimension d'ouverture L3 de l'ouverture OP, ladite dimension d'ouverture étant dans la direction x, et une région non chevauchante NOR ne chevauchant pas l'ouverture OP est formée dans chacune des unités de protection PU.
PCT/JP2014/084058 2014-12-24 2014-12-24 Capteur inertiel et son procédé de fabrication WO2016103342A1 (fr)

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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH11186566A (ja) * 1997-12-25 1999-07-09 Nissan Motor Co Ltd 微小装置の製造方法
WO2000042666A1 (fr) * 1999-01-13 2000-07-20 Mitsubishi Denki Kabushiki Kaisha Capteur de force d'inertie et procede de realisation d'un tel capteur de force d'inertie
JP2002521695A (ja) * 1998-07-31 2002-07-16 リットン システムズ インコーポレイテッド マイクロメカニカル半導体加速度計
WO2002103368A1 (fr) * 2001-06-13 2002-12-27 Mitsubishi Denki Kabushiki Kaisha Dispositif au silicium

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH11186566A (ja) * 1997-12-25 1999-07-09 Nissan Motor Co Ltd 微小装置の製造方法
JP2002521695A (ja) * 1998-07-31 2002-07-16 リットン システムズ インコーポレイテッド マイクロメカニカル半導体加速度計
WO2000042666A1 (fr) * 1999-01-13 2000-07-20 Mitsubishi Denki Kabushiki Kaisha Capteur de force d'inertie et procede de realisation d'un tel capteur de force d'inertie
WO2002103368A1 (fr) * 2001-06-13 2002-12-27 Mitsubishi Denki Kabushiki Kaisha Dispositif au silicium

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