WO2013105591A1 - Physical quantity sensor - Google Patents

Physical quantity sensor Download PDF

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Publication number
WO2013105591A1
WO2013105591A1 PCT/JP2013/050262 JP2013050262W WO2013105591A1 WO 2013105591 A1 WO2013105591 A1 WO 2013105591A1 JP 2013050262 W JP2013050262 W JP 2013050262W WO 2013105591 A1 WO2013105591 A1 WO 2013105591A1
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WO
WIPO (PCT)
Prior art keywords
movable
support
movable portion
anchor
detection
Prior art date
Application number
PCT/JP2013/050262
Other languages
French (fr)
Japanese (ja)
Inventor
尚信 大川
矢澤　久幸
高橋　亨
菊入　勝也
Original Assignee
アルプス電気株式会社
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by アルプス電気株式会社 filed Critical アルプス電気株式会社
Priority to JP2013553303A priority Critical patent/JP5747092B2/en
Publication of WO2013105591A1 publication Critical patent/WO2013105591A1/en

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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
    • 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
    • G01P2015/0805—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 being provided with a particular type of spring-mass-system for defining the displacement of a seismic mass due to an external acceleration
    • G01P2015/0822—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 being provided with a particular type of spring-mass-system for defining the displacement of a seismic mass due to an external acceleration for defining out-of-plane movement of the mass
    • G01P2015/0825—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 being provided with a particular type of spring-mass-system for defining the displacement of a seismic mass due to an external acceleration for defining out-of-plane movement of the mass for one single degree of freedom of movement of the mass
    • G01P2015/0837—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 being provided with a particular type of spring-mass-system for defining the displacement of a seismic mass due to an external acceleration for defining out-of-plane movement of the mass for one single degree of freedom of movement of the mass the mass being suspended so as to only allow movement perpendicular to the plane of the substrate, i.e. z-axis sensor

Definitions

  • the present invention relates to a physical quantity sensor capable of measuring a physical quantity such as an acceleration acting from the outside by detecting a displacement amount in a height direction of a movable part formed by cutting out from a silicon substrate or the like.
  • the physical quantity sensor includes a movable portion which is supported so as to be displaceable in the height direction by etching a silicon substrate, and a Z direction detection portion for detecting displacement of the movable portion.
  • Patent Document 1 discloses a configuration in which, when the movable portion is displaced in the height direction, the leg portion projects in a direction opposite to the displacement direction of the movable portion. The leg portion regulates the amount of displacement of the movable portion in the height direction.
  • the inventors of the present invention have intensively studied to improve detection stability as well as to improve detection sensitivity over conventional configurations.
  • the present invention is obtained from the above-described findings, and it is an object of the present invention to provide a physical quantity sensor which is particularly high in sensitivity and excellent in detection stability.
  • the present invention relates to a physical quantity sensor configured to include a movable portion displaceable in a height direction and a Z direction detection portion for detecting displacement of the movable portion.
  • a physical quantity sensor configured to include a movable portion displaceable in a height direction and a Z direction detection portion for detecting displacement of the movable portion.
  • an anchor portion fixedly supported, the movable portion, and a support portion rotatably connected to the anchor portion and the movable portion via a spring portion are separately formed, respectively.
  • the movable portion is disposed in the central region of the silicon substrate, and a pair of first anchor portions are disposed on both sides of the movable portion in the Y1-Y2 direction, and the first anchor portions are respectively disposed in the Y1-
  • a first support portion extending in an X1-X2 direction orthogonal to the Y2 direction is rotatably connected;
  • a pair of second anchor portions juxtaposed in the X1-X2 direction is arranged with respect to the pair of first anchor portions, and the pair of second anchor portions respectively extend in the X1-X2 direction
  • a second supporting portion to be released is rotatably connected and juxtaposed with the first supporting portion;
  • Each support portion is provided with a leg portion which is displaced in a direction opposite to the displacement direction of the movable portion when the support portion is rotated to displace the movable portion in the height direction.
  • the first legs respectively provided on the pair of first support portions are formed in the X1 direction from the first anchor portion, and provided on the
  • the present invention it is possible to increase the difference in natural frequency between the detection mode in the height direction and the modes other than the detection mode. Further, when the movable portion is displaced in the height direction, the leg portion is provided which is displaced in the direction opposite to the displacement direction of the movable portion and protrudes, and the leg portion can suppress the displacement of the movable portion. Then, in the state where the leg parts are in contact with the opposite surface, the four support parts of the movable part are supported by the leg parts. Further, by forming the movable portion in the central region of the silicon substrate and providing the support portion on the side of the movable portion, the area of the movable portion can be increased. This makes it possible to obtain high sensitivity and detection stability.
  • connection spring is provided between the first anchor portion and the second anchor portion to connect the first support portion and the second support portion. Is preferred. As a result, the movable portion can be moved in parallel more stably in the height direction, and detection stability can be more effectively improved.
  • the pair of first support portions is connected and integrated on the X2 side of the movable portion, and the pair of second support portions is on the X1 side of the movable portion. It is preferable that they are connected and integrated.
  • the pair of first support portions and the pair of second support portions can be stably rotated, and the movable portion can be stably translated in the height direction.
  • the first support portion is positioned outside the second support portion, and on the Y2 side of the movable portion, the second support portion is It is preferable to be located outside the said 1st support part.
  • an X-direction detection unit for detecting the displacement of the movable unit in the X1-X2 direction is formed in the movable unit.
  • both detection in the height direction (Z) of the movable part and detection in the X direction can be performed.
  • miniaturization can be realized.
  • the X direction detection unit includes an X detection movable electrode integrally formed with the movable portion, and an X detection fixed electrode formed separately from the movable portion, and the X detection movable An electrode and the X detection fixed electrode are formed by processing the silicon substrate, and the X detection movable electrode and the X detection fixed electrode face each other at an interval in the Y1-Y2 direction. It is preferable that a plurality of electrode elements be arranged in a row in the X1-X2 direction. According to the present invention, it is possible to generate an electric field that spreads in the planar direction from the end of the X detection movable electrode toward the fixed electrode of the Z direction detection unit.
  • the electrostatic capacitance generated in the Z direction detection unit can be controlled without great difference between the form in which the X direction detection unit is not formed in the movable part and the form in which the X direction detection unit is formed in the movable part. Detection sensitivity in the direction can be obtained.
  • the X direction detection unit in the present invention is an area change system, and thereby an output of change in capacitance with respect to displacement in the X direction can be obtained with good linearity, high detection accuracy can be obtained.
  • the effective detection range (dynamic range) in the X direction can be broadened.
  • the difference in natural frequency between the detection mode in the height direction and the mode other than the detection mode can be increased.
  • the leg portion is provided which is displaced in the direction opposite to the displacement direction of the movable portion and protrudes, and the leg portion can suppress the displacement of the movable portion.
  • the four support parts of the movable part are supported by the leg parts.
  • the area of the movable portion can be increased. This makes it possible to obtain high sensitivity and detection stability.
  • FIG. 1 is a plan view of a physical quantity sensor according to a first embodiment of the present invention.
  • FIG. 2 is a plan view of a physical quantity sensor according to a second embodiment of the present invention.
  • FIG. 3 is a perspective view showing a state in which the physical quantity sensor of this embodiment is stationary.
  • FIG. 4 is a perspective view showing a state in which the physical quantity sensor of this embodiment is operating.
  • FIG. 5 shows a state in which the physical quantity sensor of this embodiment operates in the opposite direction to that of FIG.
  • FIG. 6 is a partial enlarged plan view showing the first anchor portion and the second anchor portion in an enlarged manner.
  • FIG. 7 is a partially enlarged plan view showing an enlarged connection portion between the support portion and the movable portion.
  • FIG. 1 is a plan view of a physical quantity sensor according to a first embodiment of the present invention.
  • FIG. 2 is a plan view of a physical quantity sensor according to a second embodiment of the present invention.
  • FIG. 3 is a perspective
  • FIG. 8 is a front view of the physical quantity sensor in the present embodiment.
  • FIG. 9 is a partially enlarged plan view of the X-direction detection unit in the present embodiment.
  • FIG. 10 is a partially enlarged vertical sectional view showing an electric field generated between one electrode element constituting the X direction detection unit and the fixed electrode of the Z direction detection unit.
  • FIG. 11 is a plan view of a physical quantity sensor in the form of a comparative example.
  • FIG. 12 is a perspective view showing a state in which the physical quantity sensor of the comparative example is stationary.
  • FIG. 13 is a perspective view showing a state in which the physical quantity sensor of the comparative example is in operation.
  • FIG. 14 is a graph showing natural frequencies in a plurality of different modes in the first embodiment and the comparative example.
  • FIG. 15 is a graph showing natural frequencies in a plurality of different modes in the second embodiment and the comparative example.
  • FIG. 16 is a graph showing the relationship between the gap between the movable portion (the movable electrode in the Z direction) and the fixed electrode in the Z direction and the capacitance in the Z direction detection unit according to the first embodiment and the second embodiment. .
  • the X direction is the left direction
  • the X1 direction is the left direction
  • the X2 direction is the right direction
  • the Y direction is the front and back direction
  • the Y1 direction is the rear and the X2 direction is the front.
  • a direction perpendicular to both the Y direction and the X direction is the vertical direction (Z direction; height direction).
  • the physical quantity sensors 1 and 19 shown in FIGS. 1 and 2 are formed of a rectangular flat silicon substrate 8. That is, a resist layer having a planar shape corresponding to the shape of each member is formed on the silicon substrate 8, and the silicon substrate is subjected to deep reactive ion etching (DRIE) or the like in a portion where the resist layer does not exist. Each member is separated by cutting in the etching step. Therefore, each member which comprises the physical quantity sensor 1 is comprised in the range of the thickness of the surface of a silicon substrate, and a back surface.
  • DRIE deep reactive ion etching
  • the physical quantity sensor 1 is minute, for example, the long dimensions 1a and 1b of the rectangle are 1 mm or less, for example, the short dimensions 1c and 1d are 0.8 mm or less. Furthermore, the thickness dimension is 0.1 mm or less.
  • the portion formed in the central region of the silicon substrate 8 is the movable portion 2.
  • first anchor portions 6, 6 are disposed on both sides of the movable portion 2 in the front-rear direction (Y1-Y2).
  • the pair of first anchor portions 6, 6 are opposed in the front-rear direction (coincident with the line in the front-rear direction).
  • second anchor portions 7 and 7 are disposed on the left side (X1) of each of the first anchor portions 6 and 6, respectively.
  • the pair of second anchor portions 7, 7 are opposed in the front-rear direction (coincident with the line in the front-rear direction).
  • the first support portions 3, 4 extending in the left-right direction (X1-X2) respectively form the first spring portions 11, 11. It is connected rotatably via an interface.
  • “extends in the left and right direction” refers to the basic extension direction of the support portions 3 and 4, and there may be a portion bent like the first support portion 3 in the front and back direction or the like.
  • a notch is formed in the formation region of the first spring portion 11, and in the notch, the first spring portion 11 linearly extending in the front-rear direction (Y1-Y2) is The first anchor portions 6, 6 and the first support portions 3, 4 are connected to each other.
  • the first spring portion 11 is integrally formed with the first anchor portions 6 and 6 and the first support portions 3 and 4.
  • the first spring portion 11 is formed with a width that is sufficiently narrow compared to the first support portions 3 and 4 and is a portion that can be elastically deformed.
  • the rigidity of the first supports 3 and 4 is high.
  • the first legs 3a and 4a are provided on the left side (X1) of the first anchor 6 of the first support 3 and 4.
  • the first legs 3a and 4a have a function of suppressing the displacement of the movable portion 2 in the height direction.
  • the first support portion 3 located in the front (Y2) is formed to extend in the left-right direction while bending so as to pass between the first anchor portion 6 and the movable portion 2 .
  • the first support portion 4 located at the rear (Y1) is formed in a linear shape (strip shape) in the left-right direction through the outside of the first anchor portion 6.
  • the pair of first support portions 3 and 4 extend on the front and rear sides of the movable portion 2 and further on the right side (X2) of the movable portion 2 It is connected to and integrated with a first connecting portion 5 extending to Y 1 -Y 2).
  • the pair of support portions 3 and 4 are connected to each other via the movable portion 2 and the second spring portions 9 and 9, respectively.
  • the second spring portions 9 are provided on the right side of the front side surface of the movable portion 2 and on the right side of the rear side surface, respectively.
  • the second spring portion 9 is disposed in a longitudinally elongated groove 10 provided in the movable portion 2, and the second spring portion 9 is provided between the movable portion 2 and the first support portion 3. It connects between.
  • the second spring portion 9 is formed linearly long in the longitudinal direction (Y1-Y2) in the groove 10 and is folded back to connect the movable portion 2 and the first support portion 3 .
  • the second spring portion 9 has a width sufficiently smaller than that of the first support portion 3, and the second spring portion 9 is elastically deformable.
  • the second spring portion 9 is integrally formed with the movable portion 2 and the first support portion 3.
  • first support portions 3 and 4 are connected to the movable portion 2 and the first anchor portion 6 via the spring portions 9 and 11, respectively.
  • the spring portions 9 and 11 are capable of torsional deformation, which makes it possible to turn the first support portions 3 and 3 in the height direction.
  • the second support portions 13 and 14 extending in the left-right direction (X1-X2) of the pair of second anchor portions 7 and 7 respectively form the third spring portions 15 and 15. It is connected rotatably via an interface.
  • a notch is formed in the formation region of the third spring portion 15 in the second anchor portions 7, 7, and the third spring portion 15 linearly extending in the front-rear direction (Y 1 -Y 2) is formed in the notch.
  • the second anchor portion 7 and the second support portions 13 and 14 are connected to each other.
  • the third spring portion 15 is integrally formed with the second anchor portion 7 and the second support portions 13 and 14.
  • the third spring portion 15 is formed to have a width that is sufficiently narrow compared to the second support portions 13 and 14 and is a portion that can be elastically deformed.
  • the rigidity of the second support portions 13 and 14 is high.
  • the second support portions 13 and 14 are provided with second leg portions 13a and 14a on the right side (X2) of the second anchor portions 7 and 7, respectively.
  • the second legs 13a and 14a have a function of suppressing displacement of the movable portion 2 in the height direction.
  • the second support portion 13 located in the front (Y2) of the movable portion 2 passes the outside of the second anchor portion 7 and is linear (striped) in the left-right direction (X1-X2) It is extended to
  • the second support portion 14 positioned behind (Y 1) of the movable portion 2 is formed to extend in the left-right direction while bending so as to pass between the second anchor portion 7 and the movable portion 2.
  • the first supports 3 and 4 and the second supports 13 and 14 respectively formed on the front (Y2) and the rear (Y1) of the movable part 2 are the first anchor 6 and the second anchor. Except for the area where 7 intervenes, it extends in the left-right direction in a state of being opposite to each other via a minute gap.
  • the portion 14 is the same as the portion rotated about the center O of the movable portion 2 (silicon substrate 8) by 180 degrees.
  • the first support portion 3 has the same shape as that of the second support portion 14 and the movable portion 2 (silicon substrate 8) rotated 180 degrees about the center O of the movable portion 2 (silicon substrate 8).
  • the first support portion 4 has the same shape as that of the second support portion 13 and the movable portion 2 (silicon substrate 8) rotated 180 degrees about the center O of the movable portion 2 (silicon substrate 8).
  • the pair of second support portions 13 and 14 extend in the left and right direction on the front and rear sides of the movable portion 2, and further on the left side (X 1) of the movable portion 2 It is connected to and integrated with a second connecting portion 16 extending in the front-rear direction (Y1-Y2).
  • the pair of second support portions 13 and 14 are connected via the movable portion 2 and the fourth spring portions 17 and 17 respectively.
  • the form of the 4th spring part 17 is the same as that of FIG.
  • the fourth spring portions 17 and 17 are provided on the left side of the front side surface of the movable portion 2 and on the left side of the rear side surface, respectively.
  • the second support portions 13 and 14 are connected to the movable portion 2 and the second anchor portion 7 via the spring portions 15 and 17.
  • the spring portions 15 and 17 can be torsionally deformed, which allows the second support portions 13 and 14 to be pivoted in the height direction.
  • connection spring 21 which connects between the 1st support part 3 and the 2nd support part 4 is provided.
  • connection spring 21 is formed to be elongated linearly in the front-rear direction (Y1-Y2).
  • the connection spring 21 is elastically deformable.
  • connection spring 21 is located on a line in the front-rear direction (Y1-Y2) passing through the center O of the movable portion 2 (silicon substrate 8). Further, as shown in FIG. 1, the distance between the connection spring 21 and the first spring portion 11 in the left-right direction (X1-X2), and the left-right direction between the connection spring 21 and the third spring portion 15 The distance between X1 and X2 is the same.
  • the first anchor portion 6 and the second anchor portion 7 shown in FIG. 1 and the like are fixedly supported by a fixing portion (support substrate) 30 shown in FIG.
  • the fixing portion 30 is, for example, a silicon substrate, and an oxide insulating layer (SiO 2 layer) (not shown) is interposed between the anchor portions 6 and 7 and the fixing portion 30.
  • the fixed portion 30, the oxidation insulating layer, the movable portion 2 shown in FIG. 1, the support portions 3, 4, 13, 14, the anchor portions 6, 7 and the silicon substrate 8 constituting each spring are, for example, SOI substrates.
  • the movable portion 2 shown in FIG. 1, the support portions 3, 4, 13, 14 and the anchor portions 6, 7 are separately formed. Among them, the above-described oxidation insulating layer intervenes between the anchor portions 6 and 7 and the fixing portion 30, and the anchor portions 6 and 7 are in a state of being fixed and supported by the fixing portion 30.
  • the oxidation insulating layer does not exist between the fixed portion 30 and the portion 2 and the supporting portions 3, 4, 13 and 14, and the movable portion 2 and the supporting portions 3, 4, 13 and 14 and the fixed portion 30. It is a space between
  • the fixed part 30 and the opposite part 40 are provided on one side separated from the movable part 2 in the height direction.
  • the fixed electrode 41 is provided on the surface of the facing portion 40.
  • the fixed electrode 41 and the movable portion 2 face each other in the height direction (Z).
  • the facing portion 40 is, for example, a silicon substrate, and the fixed electrode 41 is formed by sputtering or plating a conductive metal material on the surface 40 a of the facing portion 40 via an insulating layer.
  • a movable electrode (not shown) facing the fixed electrode 41 is formed on the surface (lower surface) 2a of the movable portion 2 by a sputtering or plating process via an insulating layer.
  • the movable portion 2 is formed of a conductive material such as a low resistance silicon substrate, the movable portion 2 itself can be used as a movable electrode.
  • X-direction detection units 50 and 51 for detecting the displacement of the movable unit 2 in the left-right direction (X1-X2) are formed in the movable unit 2.
  • FIG. 9 is an enlarged view of a part of the X-direction detection unit 50 shown in FIG.
  • symbol 52 shown to FIG. 1, FIG. 9 (a) is a movable electrode, and the code
  • the fixed electrode 53 has an anchor portion 54 fixed and supported, and extension portions 55 and 55 extending from both sides of the anchor portion 54 in the left-right direction (X1-X2);
  • a plurality of support portions 56 (indicated by reference numerals in FIG. 9A) extending in the front-rear direction (Y1-Y2) from both sides in the front-rear direction of the extension portions 55, 55;
  • a plurality of comb-like fixed electrode elements 57 that protrude short in the direction (X1) and are disposed at predetermined intervals in the front-rear direction (Y1-Y2).
  • the anchor portion 54 is supported and fixed to the fixed portion 30 in the same manner as the anchor portions 6 and 7, and the support portion 55 extending from each of the extension portions 55 has an acceleration in the height direction (Z) described later It does not displace even if it acts.
  • FIG. 9A reference numerals are attached only to the two fixed electrode elements 57.
  • a movable electrode 52 is formed integrally with the movable portion 2.
  • the movable electrode 52 is provided with a plurality of support portions 60 extending in the front-rear direction (Y1-Y2).
  • Each support portion 60 is integrally formed from the inner side surface of the movable portion 2 and spaced from each support portion 56 of the fixed electrode 53 in the left-right direction (X1-X2).
  • only two movable electrode elements 61 are denoted by reference numerals.
  • FIG. 9B shows a state in which the movable portion 2 has moved in the left direction (X1).
  • the facing area between the movable electrode element 61 and the fixed electrode element 57 is smaller than that in the reference state of FIG.
  • the positional relationship between the movable electrode 61 and the fixed electrode 57 is the difference between the X-direction detector 50 disposed on the left side of FIG. 1 and the X-direction detector 51 disposed on the right side.
  • the capacitance is increased in the X direction detection unit 50, the capacitance is decreased in the X direction detection unit 51, and the capacitance is increased in the X direction detection unit 51.
  • the capacitance decreases in the X-direction detection unit 52.
  • a differential output can be obtained based on the change in capacitance obtained by the X-direction detection unit 50 and the change in capacitance obtained by the X-direction detection unit 51.
  • FIG. 2 is a plan view of the physical quantity sensor 19 in the second embodiment.
  • the X-direction detection units 50 and 51 are not formed in the movable unit 2 and are flat. That is, the physical quantity sensor of FIG. 10 detects only the displacement of the movable portion 2 in the height direction.
  • portions denoted with the same reference numerals as in FIG. 1 indicate the same portions as in FIG.
  • each spring part was illustrated in FIG. 2 simply.
  • the positions where the spring portions 9 and 17 are formed are different from those in FIG. 1. However, the positions of the spring portions 9 and 17 in FIG. 2 may be used in FIG. It may be a position.
  • FIG. 3 is a perspective view of the physical quantity sensor shown in FIG. 2 in a stationary state
  • FIGS. 4 and 5 are perspective views in an operating state when acceleration in the height direction is applied to the physical quantity sensor. Also in the physical quantity sensor of FIG. 1, the stationary state and the operating state are the same as those of FIGS.
  • the entire front surface and the entire back surface are respectively located on the same plane, and there is no part projecting from the front surface and the back surface.
  • the distance between the portion 2 and the fixing portion 30 is, for example, about 1 to 5 ⁇ m. Further, the distance between the movable portion 2 and the facing portion 40 is set to be approximately the same as or smaller than the distance between the movable portion 2 and the fixed portion 30.
  • FIG. 4 shows an operation when downward acceleration is applied to the anchor portions 6 and 7, the fixing portion 30 and the facing portion 40.
  • the first support portions 3 and 4 and the second support portions 13 and 14 rotate in the height direction so that the movable portion 2 is displaced upward from the position in the stationary state of FIG. 3 by inertia force. .
  • each spring portion is torsionally deformed.
  • the legs 3a, 4a, 13a, 14a of each support 3, 4, 13, 14 are displaced downward, and the tips of the legs 3a, 4a, 13a, 14a are from the movable part 2. Also protrudes downward.
  • the legs 3a, 4a, 13a, 14a When the amount of protrusion of the legs 3a, 4a, 13a, 14a increases, as shown in FIG. 8, the legs 3a, 4a, 13a, 14a are earlier than the movable part 2 abuts on the surface 30a of the fixed part 30.
  • the tip of the contact portion abuts on the surface (stopper surface) 40a of the facing portion 40, and the movable portion 2 can not be displaced further upward than the state of FIG. 8, and the displacement of the movable portion 2 is suppressed.
  • the leg portions 3a, 4a, 13a, 14a and the surface (stopper surface) 40a of the facing portion 40 constitute a stopper mechanism for suppressing the displacement of the movable portion 2.
  • FIG. 5 shows an operation when an upward acceleration acts on the anchor portions 6 and 7, the fixing portion 30 and the opposing portion 40.
  • the first support portions 3 and 4 and the second support portions 13 and 14 rotate in the height direction so that the movable portion 2 is displaced downward from the position in the stationary state of FIG. 3 by inertia force.
  • each spring portion is torsionally deformed.
  • the legs 3a, 4a, 13a, 14a of the support portions 3, 4, 13, 14 are displaced upward, and the tips of the legs 3a, 4a, 13a, 14a are movable portions 2 Project more upwards.
  • the movable portion 2 can be effectively translated in the height direction (Z) by the support mechanism of the movable portion 2 of the present embodiment.
  • the difference between the natural frequency of the detection mode in the height direction (Z) and the modes other than the detection mode can be effectively increased.
  • vibration in the front-rear direction (Y1-Y2), a diagonal direction inclined obliquely to both the front-rear direction and the left-right direction, and further both the front-rear direction and the left-right direction Rotation mode, in-plane rotation mode, etc. are included.
  • the movable mode can be moved even if a mode other than the detection mode is added in the detection mode.
  • the part 2 can be stably translated in the height direction.
  • each leg portion 3a, 4a, 13a, 14a of each support portion 3, 4, 13, 14 may be brought into contact with the surface 40a of the opposing portion 40 when a large acceleration acts.
  • the displacement of the movable portion 2 can be suppressed.
  • the tips of the legs 3a, 4a, 13a, 14a are located near the four corners of the movable part 2, in the contact state of FIG. The posture of the movable portion 2 can be stabilized.
  • the movable portion 2 is formed in the central region of the silicon substrate 8, and the supporting portions 3, 4, 13 and 14 are provided on the side of the movable portion 2. Can be Therefore, the capacitance generated between the fixed electrode 41 and the fixed electrode 41 can be increased. Further, as shown in FIG. 8, since the tips of the legs 3a, 4a, 13a and 14a abut on the surface 40a of the facing portion 40, the leg can realize a simple stopper and sticking prevention structure.
  • the surface 40 a of the facing portion 40 is a flat surface, but, for example, the height of the movable portion 2 is increased by projecting the surface 40 a at a position where the tips of the legs 3 a, 4 a, 13 a, 14 a abut.
  • the contact area between each leg and the opposing portion 40 may be reduced by restricting the amount of displacement in the longitudinal direction (Z) or reducing the area of the protrusion from the surface 40a. it can.
  • Z longitudinal direction
  • the first support portions 3 and 4 and the second support formed on the front (Y2) and the rear (Y1) of the movable portion 2 respectively.
  • the portions 13 and 14 are connected by a connecting spring 21.
  • connection spring 21 By providing the connection spring 21, it is possible to restrict the rotational states of the first support portions 3 and 4 connected by the connection spring 21 to be equal between the second support portions 13 and 14.
  • the first legs 3a and 4a provided in the first and second support portions 3 and 4 and the second legs 13a and 14a provided in the second support portions 13 and 14 are located above the movable portion 2 or The variation of the amount of protrusion can be made small and stable in the same direction below.
  • the pair of first support portions 3 and 4 are connected and integrated on the right side (X2) of the movable portion 2, and the pair The second support portions 13 and 14 are integrally connected at the left side (X1) of the movable portion 2.
  • the pair of first support portions 3 and 4 and the pair of second support portions 13 and 14 can be rotated together, thereby making the movable portion 2 more stable in the height direction. Parallel movement, and detection stability can be more effectively improved.
  • the first support portion 4 is positioned outside the second support portion 14 at the rear (Y1) of the movable portion 2 and the second support at the front (Y2) of the movable portion 2
  • the portion 13 is located outside the first support portion 3.
  • the second support portion 13 and the second support portion 13 correspond to a shape rotated 180 degrees around the center O of the movable portion 2 (silicon substrate 8).
  • the movable portion 2 in the silicon substrate 8, and the anchor portions 6 and 7, the pair of first support portions 3 and 4, and the pair of second support portions 13 and 14 on both sides of the movable portion 2 It can be arranged well and the physical quantity sensor can be miniaturized.
  • the X-direction detection units 50 and 51 in the movable unit 2 detection of displacement of the movable unit 2 in the height direction (Z) and horizontal direction (X1-X2 Both of the detection of the displacement to) can be obtained by a small physical quantity sensor.
  • the spring portions 9 and 17 connecting the movable portion 2 and the support portions 3, 4, 13 and 14 are formed to be elongated in the front-rear direction (Y 1 -Y 2), and the movable portion 2 is It is difficult to displace in the back and forth direction. Therefore, according to the physical quantity sensor 1 of the embodiment shown in FIG. 1, it is possible to stably detect the displacement in the height direction of the movable portion 2 and the displacement in the left-right direction (X1-X2).
  • the vibration performance in the height direction of the movable unit 2 is not impaired.
  • FIG. 10 is a partial longitudinal cross-sectional view of the movable electrode 61 and the fixed electrode 41 as a Z direction detection unit. Only one movable electrode 61 is shown in FIG. As shown in FIG. 10, the electric field E is generated so as to be wider than the width of the movable electrode 61 from the lower surface (end portion) 61a of the movable electrode 61 to the fixed electrode 41 opposed via the predetermined gap G. I understand that. Therefore, as shown in FIG. 1 and FIG. 9, a minute gap is formed in the movable portion 2 by providing the X direction detecting portions 50 and 51 in the movable portion 2, but the electric field E is fixed in the minute gap.
  • the expansion occurs toward the electrode 41, the decrease in electrostatic capacitance can be suppressed to a low level as compared with the embodiment in which the X-direction detection unit is not formed in the movable unit 2, or It is possible to obtain substantially the same capacitance as in the embodiment in which the X direction detection unit is not formed.
  • the output of the change of the capacitance with respect to the displacement in the left-right direction (X1-X2) is good linearity by capturing the capacitance change by the area change type instead of the parallel plate type of the X direction detection units 50 and 51 Therefore, high detection accuracy can be obtained, and further, the effective detection range (dynamic range) in the left-right direction (X1-X2) can be broadened.
  • a plurality of support portions 56 and 60 are provided in the fixed electrode 53 and the movable electrode 52, and from the support portions 56 and 60, a plurality of fixed electrode elements 57 and a plurality of movable electrode elements
  • 61 it is possible to increase the area change area when the movable portion 2 moves in the left-right direction (X1-X2), and it is possible to improve the detection sensitivity in the left-right direction.
  • the configuration of the detection portion is static. It is not limited to the capacitance type. However, by using the capacitance type, the configuration of a simple and highly accurate detection unit can be realized.
  • the present embodiment is applicable not only to acceleration sensors but also to physical quantity sensors in general, such as angular velocity sensors and impact sensors.
  • Example 1 Experiment of natural frequency in plural modes in the example and the comparative example
  • 11 to 13 show the configuration of the physical quantity sensor of the comparative example.
  • FIG. 11 is a plan view
  • FIGS. 12 and 13 are perspective views.
  • the physical quantity sensor 100 shown in the comparative example is provided with anchor parts 102 to 104 and support parts 105 to 108 inside the movable part 101.
  • the movable portion 101, the anchor portions 102 to 104 and the support portions 105 to 108 are separately formed.
  • reference numerals 109 to 120 denote spring portions.
  • leg portions 105a and 107a are provided on the support portions 105 and 107, respectively.
  • FIG. 12 shows the stationary state, and when acceleration acts in the height direction, the movable portion 101 is displaced in the height direction, and as shown in FIG. 13, the leg portions 105a and 107a are displaced in the opposite direction to the movable portion 101. The tips of the legs 105a and 107a project.
  • KHz natural frequency in different modes was determined using Example 1 shown in FIG. 1 and the comparative example described above.
  • Mode 1 in Example 1 and Comparative Example is a detection mode in the height direction (Z).
  • Mode 2 in the first embodiment is a detection mode in the left-right direction (X1-X2).
  • modes 3 to 6 in the first embodiment are modes other than the detection mode, and are a vibration mode in the back and forth direction (Y1-Y2), a rotation mode centering on the back and forth direction and the left and right direction .
  • the mode 3 to mode 6 of the first embodiment are arranged in the order of modes having lower natural frequencies.
  • mode 2 to mode 6 in the comparative example are modes other than the detection mode, and vibration modes in the lateral direction (X1-X2) and the longitudinal direction (Y1-Y2) and rotation around the longitudinal direction and the lateral direction Mode, in-plane rotation mode.
  • the mode 2 to mode 6 of the comparative example are arranged in the order of modes with low natural frequency.
  • the first embodiment is configured to detect the displacement of the movable portion in the height direction (Z) and the left and right direction (X).
  • the natural frequencies in modes 2 to 6 other than the detection mode are higher than those in mode 1 which is the detection mode, and it is possible to obtain the natural frequency difference. all right. Therefore, also in the configuration of the comparative example, the displacement in the height direction of the movable portion can be appropriately detected.
  • the natural frequencies in mode 3 to mode 6 other than the detection mode are higher in the example 1 than in the comparative example, and the natural frequency difference with the detection mode can be broadened.
  • the natural frequency difference between mode 2 which is the detection mode in the left-right direction (X) and mode 3 to mode 6 other than the detection mode should be increased as in the case of mode 1. It was possible.
  • Example 1 As described above, in Example 1, it was found that the natural frequency difference between the detection mode and the modes other than the detection mode can be increased, and excellent detection stability can be obtained.
  • Mode 1 in Example 2 and Comparative Example is a detection mode in the height direction (Z).
  • modes 2 to 6 in the second embodiment and the comparative example are modes other than the detection mode, and vibration modes in the left-right direction (X1-X2) and the front-rear direction (Y1-Y2) And the in-plane rotation mode.
  • the mode 2 to mode 6 of the embodiment 2 and the comparative example are arranged in the order of modes having low natural frequencies.
  • the result of the comparative example shown in FIG. 15 is the same as FIG. As shown in FIG. 15, when Example 2 and Comparative Example are compared, it was found that all of the natural frequencies in Mode 2 to Mode 6 other than the detection mode are higher in Example 1. As a result, it was found that the natural frequency difference between the modes 2 to 6 other than these detection modes and the mode 1 which is the detection mode in the height direction is larger in the example 2 than in the comparative example.
  • Example 2 it was found that the natural frequency difference between the detection mode and the modes other than the detection mode can be increased, and excellent detection stability can be obtained.
  • Example 2 Experiment of gap and capacitance in Example 1
  • the gap G shown in FIG. 10 was changed to obtain the capacitance in the Z direction detection unit.
  • the gap G shown in FIG. 10 was changed to obtain the capacitance in the Z direction detection unit.
  • the space formed in the movable portion 2 may be large, or the space may not be covered by the spread of the electric field. Therefore, as shown in FIGS. 1 and 9, a large number of comb-like electrodes face each other with a minute gap between the movable electrode side and the fixed electrode side of the X direction detection unit, and the movable portion 2 is movable in the lateral direction At this time, it is preferable that the electrostatic capacity changes due to a change in the facing area between the comb-like electrodes, because high sensitivity can be achieved.

Abstract

[Problem] The purpose of the invention is to provide a physical quantity sensor with particularly high sensitivity and outstanding detection stability. [Solution] Formed in mutual detachment on a silicon substrate are: anchor sections (6, 7); a movable section (2); and support sections (3, 4, 13, 14) that freely rotatably connect the anchor sections and the movable section through spring sections. A pair of first anchor sections is placed on both front/back-direction sides of the movable section (2), and a first support section that extends in the left/right direction is freely rotatably connected to each member of the pair of first anchor sections. Second anchor sections are placed in the left/right direction relative to the first anchor sections, and a second support section that extends in the left/right direction is freely rotatably connected to each member of the pair of second anchor sections. A first foot section is formed facing leftward on the first support section, and a second foot section is provided facing rightward on the second support section.

Description

物理量センサPhysical quantity sensor
　本発明は、シリコン基板から切り出すなどして形成された可動部の高さ方向への変位量を検知し、これにより、外部から作用する加速度などの物理量の測定を可能とした物理量センサに関する。 The present invention relates to a physical quantity sensor capable of measuring a physical quantity such as an acceleration acting from the outside by detecting a displacement amount in a height direction of a movable part formed by cutting out from a silicon substrate or the like.
　例えば、物理量センサは、シリコン基板をエッチング処理して、高さ方向に変位可能に支持された可動部と、可動部の変位を検知するためのＺ方向検知部とを備える。 For example, the physical quantity sensor includes a movable portion which is supported so as to be displaceable in the height direction by etching a silicon substrate, and a Z direction detection portion for detecting displacement of the movable portion.
　本出願人は、この種の物理量センサを過去において出願している（特許文献１～３）。例えば特許文献１には可動部が高さ方向に変位すると、可動部の変位方向とは逆方向に脚部が突出する構成が開示されている。脚部は、前記可動部の高さ方向への変位量を規制する。 The applicant has applied for a physical quantity sensor of this type in the past (patent documents 1 to 3). For example, Patent Document 1 discloses a configuration in which, when the movable portion is displaced in the height direction, the leg portion projects in a direction opposite to the displacement direction of the movable portion. The leg portion regulates the amount of displacement of the movable portion in the height direction.
国際公開第２０１０／１４０４６８号のパンフレットPamphlet of International Publication No. 2010/140468 国際公開第２０１０／１４０５７４号のパンフレットPamphlet of International Publication No. 2010/140574 国際公開第２０１０／００１９４７号のパンフレットPamphlet of International Publication No. 2010/001947
　本発明者らは、従来の構成よりも検出感度を高めることができるとともに検出安定性を向上させるべく鋭意研究を重ねた。 The inventors of the present invention have intensively studied to improve detection stability as well as to improve detection sensitivity over conventional configurations.
　したがって本発明は、上記知見から得られたものであり、特に高感度で検出安定性に優れた物理量センサを提供することを目的としている。 Therefore, the present invention is obtained from the above-described findings, and it is an object of the present invention to provide a physical quantity sensor which is particularly high in sensitivity and excellent in detection stability.
　本発明は、高さ方向に変位可能な可動部と、前記可動部の変位を検知するためのＺ方向検知部とを有して構成される物理量センサにおいて、
　シリコン基板には、固定支持されるアンカ部、前記可動部、及び前記アンカ部と前記可動部とにばね部を介して回動自在に連結された支持部が夫々分離して形成されており、
　前記シリコン基板の中央領域に前記可動部が配置され、前記可動部のＹ１－Ｙ２方向の両側に一対の第１のアンカ部が配置され、前記一対の第１のアンカ部に夫々、前記Ｙ１－Ｙ２方向に対して直交するＸ１－Ｘ２方向に延出する第１の支持部が回動自在に連結され、
　前記一対の第１のアンカ部に対して前記Ｘ１－Ｘ２方向に並設された一対の第２のアンカ部が配置され、前記一対の第２のアンカ部に夫々、前記Ｘ１－Ｘ２方向に延出する第２の支持部が回動自在に連結されるとともに前記第１の支持部と並設されており、
各支持部には、前記支持部が回動して前記可動部が高さ方向に変位したときに前記可動部の変位方向に対し逆方向に変位する脚部が設けられており、
　一対の前記第１の支持部に夫々設けられた第１の脚部は、前記第１のアンカ部からＸ１方向に向けて形成されており、一対の前記第２の支持部に夫々設けられた第２の脚部は、前記第２のアンカ部からＸ２方向に向けて形成されていることを特徴とするものである。 The present invention relates to a physical quantity sensor configured to include a movable portion displaceable in a height direction and a Z direction detection portion for detecting displacement of the movable portion.
On the silicon substrate, an anchor portion fixedly supported, the movable portion, and a support portion rotatably connected to the anchor portion and the movable portion via a spring portion are separately formed, respectively.
The movable portion is disposed in the central region of the silicon substrate, and a pair of first anchor portions are disposed on both sides of the movable portion in the Y1-Y2 direction, and the first anchor portions are respectively disposed in the Y1- A first support portion extending in an X1-X2 direction orthogonal to the Y2 direction is rotatably connected;
A pair of second anchor portions juxtaposed in the X1-X2 direction is arranged with respect to the pair of first anchor portions, and the pair of second anchor portions respectively extend in the X1-X2 direction A second supporting portion to be released is rotatably connected and juxtaposed with the first supporting portion;
Each support portion is provided with a leg portion which is displaced in a direction opposite to the displacement direction of the movable portion when the support portion is rotated to displace the movable portion in the height direction.
The first legs respectively provided on the pair of first support portions are formed in the X1 direction from the first anchor portion, and provided on the pair of second support portions respectively. The second leg portion is characterized in that it is formed in the X2 direction from the second anchor portion.
　本発明によれば、高さ方向への検出モードと、前記検出モード以外のモードとの固有振動数の差を大きくできる。また可動部が高さ方向に変位したときに、可動部の変位方向とは逆方向に変位して突出する脚部を設けており、脚部により可動部の変位を抑制できる。そして脚部が対向面に接触した状態では、脚部により可動部の四隅付近が支えられる形態となる。またシリコン基板の中央領域に可動部を形成し、可動部の側方に支持部を設けることで、可動部の面積を広くすることができる。これにより高感度で且つ検出安定性を得ることが可能となる。 According to the present invention, it is possible to increase the difference in natural frequency between the detection mode in the height direction and the modes other than the detection mode. Further, when the movable portion is displaced in the height direction, the leg portion is provided which is displaced in the direction opposite to the displacement direction of the movable portion and protrudes, and the leg portion can suppress the displacement of the movable portion. Then, in the state where the leg parts are in contact with the opposite surface, the four support parts of the movable part are supported by the leg parts. Further, by forming the movable portion in the central region of the silicon substrate and providing the support portion on the side of the movable portion, the area of the movable portion can be increased. This makes it possible to obtain high sensitivity and detection stability.
　本発明では、前記第１のアンカ部と前記第２のアンカ部との間には、前記第１の支持部と前記第２の支持部との間を連結する連結ばねが設けられていることが好ましい。これにより可動部を高さ方向により安定して平行移動させることができ、検出安定性をより効果的に向上させることができる。 In the present invention, a connection spring is provided between the first anchor portion and the second anchor portion to connect the first support portion and the second support portion. Is preferred. As a result, the movable portion can be moved in parallel more stably in the height direction, and detection stability can be more effectively improved.
　また本発明では、前記一対の第１の支持部は、前記可動部のＸ２側にて連結されて一体化しており、前記一対の前記第２の支持部は、前記可動部のＸ１側にて連結されて一体化していることが好ましい。これにより、一対の第１の支持部及び一対の前記第２の支持部を夫々、安定して回動させることができ、可動部を高さ方向により安定して平行移動させることができる。 Further, in the present invention, the pair of first support portions is connected and integrated on the X2 side of the movable portion, and the pair of second support portions is on the X1 side of the movable portion. It is preferable that they are connected and integrated. Thus, the pair of first support portions and the pair of second support portions can be stably rotated, and the movable portion can be stably translated in the height direction.
　また本発明では、前記可動部のＹ１側では、前記第１の支持部が前記第２の支持部よりも外側に位置しており、前記可動部のＹ２側では、前記第２の支持部が前記第１の支持部よりも外側に位置していることが好ましい。 In the present invention, on the Y1 side of the movable portion, the first support portion is positioned outside the second support portion, and on the Y2 side of the movable portion, the second support portion is It is preferable to be located outside the said 1st support part.
　また本発明では、前記可動部内には、前記可動部のＸ１－Ｘ２方向への変位を検知するためのＸ方向検知部が形成されることが好ましい。これにより、可動部の高さ方向（Ｚ）への検知とＸ方向への検知の双方を行うことができる。また、可動部の高さ方向への振動性能を損なうことがなく、安定した検出精度を得ることが可能となる。また小型化を実現できる。 In the present invention, it is preferable that an X-direction detection unit for detecting the displacement of the movable unit in the X1-X2 direction is formed in the movable unit. Thereby, both detection in the height direction (Z) of the movable part and detection in the X direction can be performed. In addition, it is possible to obtain stable detection accuracy without deteriorating the vibration performance in the height direction of the movable portion. In addition, miniaturization can be realized.
　また本発明では、前記Ｘ方向検知部は、前記可動部と一体に形成されたＸ検知可動電極と、前記可動部と分離して形成されたＸ検知固定電極とを有し、前記Ｘ検知可動電極と前記Ｘ検知固定電極とが前記シリコン基板を加工して形成されたものであり、前記Ｘ検知可動電極及び前記Ｘ検知固定電極には夫々、Ｙ１－Ｙ２方向にて間隔を空けて対向する複数の電極子がＸ１－Ｘ２方向に列を成して構成されていることが好ましい。本発明では、Ｘ検知可動電極の端部からＺ方向検知部の固定電極方向に向けて平面方向に広がる電界を発生させることができる。このためＺ方向検知部にて発生する静電容量を、可動部内にＸ方向検知部を形成しない形態と、可動部内にＸ方向検知部を形成した形態とで大差なく制御でき、良好な高さ方向への検出感度を得ることができる。また本発明でのＸ方向検知部は面積変化方式であり、これによりＸ方向の変位に対する静電容量の変化の出力を良好な線形性を有した状態で得られるため、高い検出精度を得ることができ、さらに、Ｘ方向への有効検出範囲（ダイナミックレンジ）を広くできる。 Further, in the present invention, the X direction detection unit includes an X detection movable electrode integrally formed with the movable portion, and an X detection fixed electrode formed separately from the movable portion, and the X detection movable An electrode and the X detection fixed electrode are formed by processing the silicon substrate, and the X detection movable electrode and the X detection fixed electrode face each other at an interval in the Y1-Y2 direction. It is preferable that a plurality of electrode elements be arranged in a row in the X1-X2 direction. According to the present invention, it is possible to generate an electric field that spreads in the planar direction from the end of the X detection movable electrode toward the fixed electrode of the Z direction detection unit. For this reason, the electrostatic capacitance generated in the Z direction detection unit can be controlled without great difference between the form in which the X direction detection unit is not formed in the movable part and the form in which the X direction detection unit is formed in the movable part. Detection sensitivity in the direction can be obtained. In addition, since the X direction detection unit in the present invention is an area change system, and thereby an output of change in capacitance with respect to displacement in the X direction can be obtained with good linearity, high detection accuracy can be obtained. In addition, the effective detection range (dynamic range) in the X direction can be broadened.
　本発明の構成によれば、高さ方向への検出モードと、前記検出モード以外のモードとの固有振動数の差を大きくできる。また可動部が高さ方向に変位したときに、可動部の変位方向とは逆方向に変位して突出する脚部を設けており、脚部により可動部の変位を抑制できる。そして脚部が対向面に接触した状態では、脚部により可動部の四隅付近が支えられる形態となる。またシリコン基板の中央領域に可動部を形成し、可動部の側方に支持部を設けることで、可動部の面積を広くすることができる。これにより高感度で且つ検出安定性を得ることが可能となる。 According to the configuration of the present invention, the difference in natural frequency between the detection mode in the height direction and the mode other than the detection mode can be increased. Further, when the movable portion is displaced in the height direction, the leg portion is provided which is displaced in the direction opposite to the displacement direction of the movable portion and protrudes, and the leg portion can suppress the displacement of the movable portion. Then, in the state where the leg parts are in contact with the opposite surface, the four support parts of the movable part are supported by the leg parts. Further, by forming the movable portion in the central region of the silicon substrate and providing the support portion on the side of the movable portion, the area of the movable portion can be increased. This makes it possible to obtain high sensitivity and detection stability.
図１は、本発明の第１の実施形態における物理量センサの平面図である。FIG. 1 is a plan view of a physical quantity sensor according to a first embodiment of the present invention. 図２は、本発明の第２の実施形態における物理量センサの平面図である。FIG. 2 is a plan view of a physical quantity sensor according to a second embodiment of the present invention. 図３は、本実施形態の物理量センサが静止している状態を示す斜視図である。FIG. 3 is a perspective view showing a state in which the physical quantity sensor of this embodiment is stationary. 図４は、本実施形態の物理量センサが動作している状態を示す斜視図である。FIG. 4 is a perspective view showing a state in which the physical quantity sensor of this embodiment is operating. 図５は、本実施形態の物理量センサが図４とは逆向きに動作している状態を示す。FIG. 5 shows a state in which the physical quantity sensor of this embodiment operates in the opposite direction to that of FIG. 図６は、第１アンカ部及び第２アンカ部を拡大して示した部分拡大平面図である。FIG. 6 is a partial enlarged plan view showing the first anchor portion and the second anchor portion in an enlarged manner. 図７は、支持部と可動部との連結部分を拡大して示した部分拡大平面図である。FIG. 7 is a partially enlarged plan view showing an enlarged connection portion between the support portion and the movable portion. 図８は、本実施形態における物理量センサの正面図である。FIG. 8 is a front view of the physical quantity sensor in the present embodiment. 図９は、本実施形態におけるＸ方向検知部の部分拡大平面図である。FIG. 9 is a partially enlarged plan view of the X-direction detection unit in the present embodiment. 図１０は、Ｘ方向検知部を構成する一つの電極子とＺ方向検知部の固定電極との間で生じた電界を示す部分拡大縦断面図である。FIG. 10 is a partially enlarged vertical sectional view showing an electric field generated between one electrode element constituting the X direction detection unit and the fixed electrode of the Z direction detection unit. 図１１は、比較例の形態における物理量センサの平面図である。FIG. 11 is a plan view of a physical quantity sensor in the form of a comparative example. 図１２は、比較例の物理量センサが静止している状態を示す斜視図である。FIG. 12 is a perspective view showing a state in which the physical quantity sensor of the comparative example is stationary. 図１３は、比較例の物理量センサが動作している状態を示す斜視図である。FIG. 13 is a perspective view showing a state in which the physical quantity sensor of the comparative example is in operation. 図１４は、第１の実施形態と比較例における複数の異なるモード時の固有振動数を示すグラフである。FIG. 14 is a graph showing natural frequencies in a plurality of different modes in the first embodiment and the comparative example. 図１５は、第２の実施形態と比較例における複数の異なるモード時の固有振動数を示すグラフである。FIG. 15 is a graph showing natural frequencies in a plurality of different modes in the second embodiment and the comparative example. 図１６は、第１の実施形態と第２の実施形態のＺ方向検知部における、可動部（Ｚ方向可動電極）とＺ方向固定電極間のギャップと静電容量との関係を示すグラフである。FIG. 16 is a graph showing the relationship between the gap between the movable portion (the movable electrode in the Z direction) and the fixed electrode in the Z direction and the capacitance in the Z direction detection unit according to the first embodiment and the second embodiment. .
　各図に示す物理量センサに関しては、Ｘ方向が左右方向であり、Ｘ１方向が左方向でＸ２方向が右方向、Ｙ方向が前後方向であり、Ｙ１方向が後方でＸ２方向が前方である。また、Ｙ方向とＸ方向の双方に直交する方向が上下方向（Ｚ方向；高さ方向）である。 Regarding the physical quantity sensor shown in each drawing, the X direction is the left direction, the X1 direction is the left direction, the X2 direction is the right direction, the Y direction is the front and back direction, and the Y1 direction is the rear and the X2 direction is the front. Further, a direction perpendicular to both the Y direction and the X direction is the vertical direction (Z direction; height direction).
　図１，図２に示す物理量センサ１，１９は、長方形の平板状のシリコン基板８から形成されている。すなわち、シリコン基板８に、各部材の形状に対応する平面形状のレジスト層を形成し、レジスト層が存在していない部分で、シリコン基板をディープＲＩＥ（ディープ・リアクティブ・イオン・エッチング）などのエッチング工程で切断することで、各部材を分離している。したがって、物理量センサ１を構成する各部材は、シリコン基板の表面と裏面の厚みの範囲内で構成されている。 The physical quantity sensors 1 and 19 shown in FIGS. 1 and 2 are formed of a rectangular flat silicon substrate 8. That is, a resist layer having a planar shape corresponding to the shape of each member is formed on the silicon substrate 8, and the silicon substrate is subjected to deep reactive ion etching (DRIE) or the like in a portion where the resist layer does not exist. Each member is separated by cutting in the etching step. Therefore, each member which comprises the physical quantity sensor 1 is comprised in the range of the thickness of the surface of a silicon substrate, and a back surface.
　物理量センサ１は微小であり、例えば長方形の長辺１ａ，１ｂの長さ寸法は１ｍｍ以下であり、例えば短辺１ｃ，１ｄの長さ寸法は０．８ｍｍ以下である。さらに、厚み寸法は０．１ｍｍ以下である。 The physical quantity sensor 1 is minute, for example, the long dimensions 1a and 1b of the rectangle are 1 mm or less, for example, the short dimensions 1c and 1d are 0.8 mm or less. Furthermore, the thickness dimension is 0.1 mm or less.
　図１に示すように、物理量センサ１は、シリコン基板８の中央領域に形成された部分が可動部２である。 As shown in FIG. 1, in the physical quantity sensor 1, the portion formed in the central region of the silicon substrate 8 is the movable portion 2.
　図１に示すように可動部２の前後方向（Ｙ１－Ｙ２）の両側に第１のアンカ部６，６が配置されている。一対の第１のアンカ部６，６は前後方向で対向している（前後方向の線上に一致している）。また各第１のアンカ部６，６の左側（Ｘ１）には夫々、第２のアンカ部７，７が配置されている。一対の第２のアンカ部７，７は前後方向で対向している（前後方向の線上に一致している）。 As shown in FIG. 1, first anchor portions 6, 6 are disposed on both sides of the movable portion 2 in the front-rear direction (Y1-Y2). The pair of first anchor portions 6, 6 are opposed in the front-rear direction (coincident with the line in the front-rear direction). In addition, second anchor portions 7 and 7 are disposed on the left side (X1) of each of the first anchor portions 6 and 6, respectively. The pair of second anchor portions 7, 7 are opposed in the front-rear direction (coincident with the line in the front-rear direction).
　図１に示すように、一対の第１のアンカ部６，６には夫々、左右方向（Ｘ１－Ｘ２）に延出する第１の支持部３，４が第１のばね部１１，１１を介して回動自在に連結されている。ここで「左右方向に延出する」とは支持部３，４の基本的な延出方向を指し、第１の支持部３のように前後方向等に折り曲がる部分があってもよい。第１のアンカ部６，６には第１のばね部１１の形成領域に切欠部が形成され、その切欠部内に前後方向（Ｙ１－Ｙ２）に直線状に延びる第１のばね部１１が、第１のアンカ部６，６と第１の支持部３，４との間を連結している。第１のばね部１１は、第１のアンカ部６，６及び第１の支持部３，４と一体で形成される。第１のばね部１１は、第１の支持部３，４に比べて十分に狭い幅寸法で形成され、弾性変形可能な部分となっている。一方、第１の支持部３，４の剛性は高くなっている。 As shown in FIG. 1, in the pair of first anchor portions 6, 6, the first support portions 3, 4 extending in the left-right direction (X1-X2) respectively form the first spring portions 11, 11. It is connected rotatably via an interface. Here, “extends in the left and right direction” refers to the basic extension direction of the support portions 3 and 4, and there may be a portion bent like the first support portion 3 in the front and back direction or the like. In the first anchor portions 6 and 6, a notch is formed in the formation region of the first spring portion 11, and in the notch, the first spring portion 11 linearly extending in the front-rear direction (Y1-Y2) is The first anchor portions 6, 6 and the first support portions 3, 4 are connected to each other. The first spring portion 11 is integrally formed with the first anchor portions 6 and 6 and the first support portions 3 and 4. The first spring portion 11 is formed with a width that is sufficiently narrow compared to the first support portions 3 and 4 and is a portion that can be elastically deformed. On the other hand, the rigidity of the first supports 3 and 4 is high.
　図１に示すように第１の支持部３，４の第１のアンカ部６よりも左方（Ｘ１）に第１の脚部３ａ，４ａが設けられている。第１の脚部３ａ，４ａは可動部２の高さ方向への変位を抑制する機能を備える。 As shown in FIG. 1, the first legs 3a and 4a are provided on the left side (X1) of the first anchor 6 of the first support 3 and 4. The first legs 3a and 4a have a function of suppressing the displacement of the movable portion 2 in the height direction.
　図１に示すように、前方（Ｙ２）に位置する第１の支持部３は、第１のアンカ部６と可動部２との間を通るように折れ曲がりながら左右方向に延びて形成されている。また後方（Ｙ１）に位置する第１の支持部４は、第１のアンカ部６の外側を通って左右方向に直線状（帯状）に形成される。 As shown in FIG. 1, the first support portion 3 located in the front (Y2) is formed to extend in the left-right direction while bending so as to pass between the first anchor portion 6 and the movable portion 2 . In addition, the first support portion 4 located at the rear (Y1) is formed in a linear shape (strip shape) in the left-right direction through the outside of the first anchor portion 6.
　図１に示すように一対の第１の支持部３，４は、可動部２の前方及び後方の各側方にて延在し、さらに可動部２の右側方（Ｘ２）にて前後方向（Ｙ１－Ｙ２）に延びる第１の連結部５に連結されて一体化している。 As shown in FIG. 1, the pair of first support portions 3 and 4 extend on the front and rear sides of the movable portion 2 and further on the right side (X2) of the movable portion 2 It is connected to and integrated with a first connecting portion 5 extending to Y 1 -Y 2).
　また図１に示すように一対の支持部３，４は夫々、可動部２と第２のばね部９，９を介して連結されている。第２のばね部９，９は、可動部２の前方側面の右側、及び後方側面の右側に夫々設けられている。 Further, as shown in FIG. 1, the pair of support portions 3 and 4 are connected to each other via the movable portion 2 and the second spring portions 9 and 9, respectively. The second spring portions 9 are provided on the right side of the front side surface of the movable portion 2 and on the right side of the rear side surface, respectively.
　図７の部分拡大平面図で示すように、第２のばね部９は、可動部２に設けられた前後方向に細長い溝１０内に配置され、可動部２と第１の支持部３との間を連結している。第２のばね部９は、溝１０内で前後方向（Ｙ１－Ｙ２）に直線状に長く形成され、また折り返されて、可動部２と第１の支持部３との間を連結している。第２のばね部９は、第１の支持部３に比べて幅寸法が十分小さく、第２のばね部９は、弾性変形可能とされている。第２のばね部９は、可動部２及び第１の支持部３と一体に形成される。 As shown in the partial enlarged plan view of FIG. 7, the second spring portion 9 is disposed in a longitudinally elongated groove 10 provided in the movable portion 2, and the second spring portion 9 is provided between the movable portion 2 and the first support portion 3. It connects between. The second spring portion 9 is formed linearly long in the longitudinal direction (Y1-Y2) in the groove 10 and is folded back to connect the movable portion 2 and the first support portion 3 . The second spring portion 9 has a width sufficiently smaller than that of the first support portion 3, and the second spring portion 9 is elastically deformable. The second spring portion 9 is integrally formed with the movable portion 2 and the first support portion 3.
　このように第１の支持部３，４は、可動部２と第１のアンカ部６とにばね部９，１１を介して連結されている。ばね部９，１１は捩れ変形可能とされており、これにより第１の支持部３，３を高さ方向に回動させることが可能となっている。 Thus, the first support portions 3 and 4 are connected to the movable portion 2 and the first anchor portion 6 via the spring portions 9 and 11, respectively. The spring portions 9 and 11 are capable of torsional deformation, which makes it possible to turn the first support portions 3 and 3 in the height direction.
　また、図１に示すように、一対の第２のアンカ部７，７には夫々、左右方向（Ｘ１－Ｘ２）に延びる第２の支持部１３，１４が第３のばね部１５，１５を介して回動自在に連結されている。第２のアンカ部７，７には第３のばね部１５の形成領域に切欠部が形成され、その切欠部内に前後方向（Ｙ１－Ｙ２）に直線状に延びる第３のばね部１５が、第２のアンカ部７と第２の支持部１３，１４との間を連結している。第３のばね部１５は、第２のアンカ部７と第２の支持部１３，１４と一体で形成される。第３のばね部１５は、第２の支持部１３，１４に比べて十分に狭い幅寸法で形成され、弾性変形可能な部分となっている。一方、第２の支持部１３，１４の剛性は高くなっている。 In addition, as shown in FIG. 1, the second support portions 13 and 14 extending in the left-right direction (X1-X2) of the pair of second anchor portions 7 and 7 respectively form the third spring portions 15 and 15. It is connected rotatably via an interface. A notch is formed in the formation region of the third spring portion 15 in the second anchor portions 7, 7, and the third spring portion 15 linearly extending in the front-rear direction (Y 1 -Y 2) is formed in the notch. The second anchor portion 7 and the second support portions 13 and 14 are connected to each other. The third spring portion 15 is integrally formed with the second anchor portion 7 and the second support portions 13 and 14. The third spring portion 15 is formed to have a width that is sufficiently narrow compared to the second support portions 13 and 14 and is a portion that can be elastically deformed. On the other hand, the rigidity of the second support portions 13 and 14 is high.
　図１に示すように第２の支持部１３，１４には第２のアンカ部７，７よりも右方（Ｘ２）に第２の脚部１３ａ，１４ａが設けられている。第２の脚部１３ａ，１４ａは可動部２の高さ方向への変位を抑制する機能を備える。 As shown in FIG. 1, the second support portions 13 and 14 are provided with second leg portions 13a and 14a on the right side (X2) of the second anchor portions 7 and 7, respectively. The second legs 13a and 14a have a function of suppressing displacement of the movable portion 2 in the height direction.
　図１に示すように、可動部２の前方（Ｙ２）に位置する第２の支持部１３は、第２のアンカ部７の外側を通って左右方向（Ｘ１－Ｘ２）に直線状（帯状）に延出している。 As shown in FIG. 1, the second support portion 13 located in the front (Y2) of the movable portion 2 passes the outside of the second anchor portion 7 and is linear (striped) in the left-right direction (X1-X2) It is extended to
　また、可動部２の後方（Ｙ１）に位置する第２の支持部１４は、第２のアンカ部７と可動部２との間を通るように折れ曲がりながら左右方向に延びて形成されている。 Further, the second support portion 14 positioned behind (Y 1) of the movable portion 2 is formed to extend in the left-right direction while bending so as to pass between the second anchor portion 7 and the movable portion 2.
　可動部２の前方（Ｙ２）及び後方（Ｙ１）の夫々に形成された第１の支持部３，４と第２の支持部１３，１４は、第１のアンカ部６及び第２のアンカ部７が介在する領域を除き、微小隙間を介して相対向した状態で左右方向に延びている。 The first supports 3 and 4 and the second supports 13 and 14 respectively formed on the front (Y2) and the rear (Y1) of the movable part 2 are the first anchor 6 and the second anchor. Except for the area where 7 intervenes, it extends in the left-right direction in a state of being opposite to each other via a minute gap.
　可動部２の前方（Ｙ２）に配置された第１の支持部３及び第２の支持部１３と、可動部２の後方（Ｙ１）に配置された第１の支持部４及び第２の支持部１４とは互いに、可動部２（シリコン基板８）の中心Ｏを中心軸として１８０度回転させた形態と同じとなっている。このため図１に示すように、第１の支持部３は、第２の支持部１４と可動部２（シリコン基板８）の中心Ｏを中心軸として１８０度回転させた形態と同じとなっており、また、第１の支持部４は、第２の支持部１３と可動部２（シリコン基板８）の中心Ｏを中心軸として１８０度回転させた形態と同じとなっている。 First support portion 3 and second support portion 13 disposed in front of movable portion 2 (Y2), and first support portion 4 and second support disposed in rear (Y1) of movable portion 2 The portion 14 is the same as the portion rotated about the center O of the movable portion 2 (silicon substrate 8) by 180 degrees. For this reason, as shown in FIG. 1, the first support portion 3 has the same shape as that of the second support portion 14 and the movable portion 2 (silicon substrate 8) rotated 180 degrees about the center O of the movable portion 2 (silicon substrate 8). In addition, the first support portion 4 has the same shape as that of the second support portion 13 and the movable portion 2 (silicon substrate 8) rotated 180 degrees about the center O of the movable portion 2 (silicon substrate 8).
　図１に示すように一対の第２の支持部１３，１４は、可動部２の前方及び後方の各側方にて左右方向に延在し、さらに可動部２の左側方（Ｘ１）にて前後方向（Ｙ１－Ｙ２）に延びる第２の連結部１６に連結されて一体化している。 As shown in FIG. 1, the pair of second support portions 13 and 14 extend in the left and right direction on the front and rear sides of the movable portion 2, and further on the left side (X 1) of the movable portion 2 It is connected to and integrated with a second connecting portion 16 extending in the front-rear direction (Y1-Y2).
　また図１に示すように一対の第２の支持部１３，１４は夫々、可動部２と第４のばね部１７，１７を介して連結されている。第４のばね部１７の形態は図７と同様である。第４のばね部１７，１７は、可動部２の前方側面の左側、及び後方側面の左側に夫々設けられている。 Further, as shown in FIG. 1, the pair of second support portions 13 and 14 are connected via the movable portion 2 and the fourth spring portions 17 and 17 respectively. The form of the 4th spring part 17 is the same as that of FIG. The fourth spring portions 17 and 17 are provided on the left side of the front side surface of the movable portion 2 and on the left side of the rear side surface, respectively.
　このように第２の支持部１３，１４は、可動部２と第２のアンカ部７とにばね部１５，１７を介して連結されている。ばね部１５，１７は捩れ変形可能とされており、これにより第２の支持部１３，１４を高さ方向に回動させることが可能となっている。 Thus, the second support portions 13 and 14 are connected to the movable portion 2 and the second anchor portion 7 via the spring portions 15 and 17. The spring portions 15 and 17 can be torsionally deformed, which allows the second support portions 13 and 14 to be pivoted in the height direction.
　図１，図６に示すように、第１のアンカ部６と第２のアンカ部７との間には左右方向（Ｘ１－Ｘ２）に間隔を空けて前後方向（Ｙ１－Ｙ２）に延びる隙間２０が形成されている。そして、この隙間２０内に、第１の支持部３と第２の支持部４との間を連結する連結ばね２１が設けられている。 As shown in FIGS. 1 and 6, a gap extending in the front-rear direction (Y1-Y2) spaced apart in the left-right direction (X1-X2) between the first anchor portion 6 and the second anchor portion 7 20 are formed. And in this clearance gap 20, the connection spring 21 which connects between the 1st support part 3 and the 2nd support part 4 is provided.
　図６に示すように連結ばね２１は前後方向（Ｙ１－Ｙ２）に直線状に細長く形成される。連結ばね２１は弾性変形可能とされている。 As shown in FIG. 6, the connection spring 21 is formed to be elongated linearly in the front-rear direction (Y1-Y2). The connection spring 21 is elastically deformable.
　図１に示すように、連結ばね２１は、可動部２（シリコン基板８）の中心Ｏを通る前後方向（Ｙ１－Ｙ２）の線上に位置している。また、図１に示すように連結ばね２１と第１のばね部１１との間の左右方向（Ｘ１－Ｘ２）の距離、及び連結ばね２１と第３のばね部１５との間の左右方向（Ｘ１－Ｘ２）の距離は同じとなっている。 As shown in FIG. 1, the connection spring 21 is located on a line in the front-rear direction (Y1-Y2) passing through the center O of the movable portion 2 (silicon substrate 8). Further, as shown in FIG. 1, the distance between the connection spring 21 and the first spring portion 11 in the left-right direction (X1-X2), and the left-right direction between the connection spring 21 and the third spring portion 15 The distance between X1 and X2 is the same.
　図１等で示した第１のアンカ部６及び第２のアンカ部７は、図８に示す固定部（支持基板）３０に固定支持される。この固定部３０は例えばシリコン基板であり、各アンカ部６、７と固定部３０との間には図示しない酸化絶縁層（ＳｉＯ2層）が介在している。固定部３０、酸化絶縁層、及び図１に示す可動部２、支持部３，４，１３，１４、アンカ部６，７及び各ばねを構成するシリコン基板８は、例えばＳＯＩ基板である。 The first anchor portion 6 and the second anchor portion 7 shown in FIG. 1 and the like are fixedly supported by a fixing portion (support substrate) 30 shown in FIG. The fixing portion 30 is, for example, a silicon substrate, and an oxide insulating layer (SiO 2 layer) (not shown) is interposed between the anchor portions 6 and 7 and the fixing portion 30. The fixed portion 30, the oxidation insulating layer, the movable portion 2 shown in FIG. 1, the support portions 3, 4, 13, 14, the anchor portions 6, 7 and the silicon substrate 8 constituting each spring are, for example, SOI substrates.
　図１に示す可動部２、各支持部３，４，１３，１４及び各アンカ部６，７は夫々分離して形成されている。このうち、各アンカ部６，７と固定部３０との間には上記した酸化絶縁層が介在し、各アンカ部６，７が固定部３０に固定支持された状態になっているが、可動部２及び各支持部３，４，１３，１４と、固定部３０との間には酸化絶縁層は存在せず、可動部２及び各支持部３，４，１３，１４と固定部３０との間は空間となっている。 The movable portion 2 shown in FIG. 1, the support portions 3, 4, 13, 14 and the anchor portions 6, 7 are separately formed. Among them, the above-described oxidation insulating layer intervenes between the anchor portions 6 and 7 and the fixing portion 30, and the anchor portions 6 and 7 are in a state of being fixed and supported by the fixing portion 30. The oxidation insulating layer does not exist between the fixed portion 30 and the portion 2 and the supporting portions 3, 4, 13 and 14, and the movable portion 2 and the supporting portions 3, 4, 13 and 14 and the fixed portion 30. It is a space between
　図８に示すように、物理量センサ１には、可動部２と高さ方向にて離れた一方に固定部３０と他方に対向部４０が設けられる。対向部４０の表面には固定電極４１が設けられる。固定電極４１と可動部２とは高さ方向（Ｚ）にて相対向している。 As shown in FIG. 8, in the physical quantity sensor 1, the fixed part 30 and the opposite part 40 are provided on one side separated from the movable part 2 in the height direction. The fixed electrode 41 is provided on the surface of the facing portion 40. The fixed electrode 41 and the movable portion 2 face each other in the height direction (Z).
　対向部４０は例えばシリコン基板であり、固定電極４１は、対向部４０の表面４０ａに絶縁層を介して導電性金属材料をスパッタしまたはメッキすることで形成されている。 The facing portion 40 is, for example, a silicon substrate, and the fixed electrode 41 is formed by sputtering or plating a conductive metal material on the surface 40 a of the facing portion 40 via an insulating layer.
　また、可動部２の表面（下面）２ａには、固定電極４１に対面する可動電極（図示しない）が絶縁層を介してスパッタやメッキ工程で形成されている。あるいは、可動部２が、低抵抗シリコン基板などの導電性材料で形成されている場合には、可動部２それ自体を可動電極として使用することが可能である。 A movable electrode (not shown) facing the fixed electrode 41 is formed on the surface (lower surface) 2a of the movable portion 2 by a sputtering or plating process via an insulating layer. Alternatively, in the case where the movable portion 2 is formed of a conductive material such as a low resistance silicon substrate, the movable portion 2 itself can be used as a movable electrode.
　図１に示す実施形態では、可動部２内に可動部２の左右方向（Ｘ１－Ｘ２）への変位を検知するためのＸ方向検知部５０，５１が形成されている。 In the embodiment shown in FIG. 1, X-direction detection units 50 and 51 for detecting the displacement of the movable unit 2 in the left-right direction (X1-X2) are formed in the movable unit 2.
　Ｘ方向検知部５０，５１について図９の部分拡大平面図を用いて説明する。図９は図１に示すＸ方向検知部５０の一部を拡大したものである。図１、図９（ａ）に示す符号５２は可動電極で、符号５３は固定電極である。 The X direction detection units 50 and 51 will be described using a partial enlarged plan view of FIG. FIG. 9 is an enlarged view of a part of the X-direction detection unit 50 shown in FIG. The code | symbol 52 shown to FIG. 1, FIG. 9 (a) is a movable electrode, and the code | symbol 53 is a fixed electrode.
　図１，図９（ａ）に示すように固定電極５３は固定支持されたアンカ部５４と、アンカ部５４の両側から左右方向（Ｘ１－Ｘ２）に延出する延出部５５，５５と、各延出部５５，５５の前後方向の両側から前後方向（Ｙ１－Ｙ２）に延出する複数本の支持部５６（図９（ａ）に符号を付した）と、各支持部５６から左方向（Ｘ１）に短く突出し、かつ前後方向（Ｙ１－Ｙ２）に所定の間隔を空けて配置された複数本の櫛歯状の固定電極子５７と、を有して構成される。アンカ部５４はアンカ部６，７と同様、固定部３０に支持固定されており、各延出部５５，５５から延出する支持部５５は、後述する高さ方向（Ｚ）への加速度が作用しても変位しない。なお図９（ａ）には、２本の固定電極子５７にのみ符号を付した。 As shown in FIGS. 1 and 9A, the fixed electrode 53 has an anchor portion 54 fixed and supported, and extension portions 55 and 55 extending from both sides of the anchor portion 54 in the left-right direction (X1-X2); A plurality of support portions 56 (indicated by reference numerals in FIG. 9A) extending in the front-rear direction (Y1-Y2) from both sides in the front-rear direction of the extension portions 55, 55; A plurality of comb-like fixed electrode elements 57 that protrude short in the direction (X1) and are disposed at predetermined intervals in the front-rear direction (Y1-Y2). The anchor portion 54 is supported and fixed to the fixed portion 30 in the same manner as the anchor portions 6 and 7, and the support portion 55 extending from each of the extension portions 55 has an acceleration in the height direction (Z) described later It does not displace even if it acts. In FIG. 9A, reference numerals are attached only to the two fixed electrode elements 57.
　また図１に示すように、可動部２と一体となって可動電極５２が形成されている。可動電極５２には、図９（ａ）に示すように、前後方向（Ｙ１－Ｙ２）に延出する複数の支持部６０が形成されている。各支持部６０は、可動部２の内側側面から一体となって且つ固定電極５３の各支持部５６と左右方向（Ｘ１－Ｘ２）に間隔を空けて配置されている。また図９（ａ）に示すように、各支持部６０の右側面から右方向（Ｘ２）に短く突出した複数本の可動電極子６１が固定電極子５７と前後方向（Ｙ１－Ｙ２）に交互に配置されている。なお図９（ａ）には、２本の可動電極子６１にのみ符号を付した。 Further, as shown in FIG. 1, a movable electrode 52 is formed integrally with the movable portion 2. As shown in FIG. 9A, the movable electrode 52 is provided with a plurality of support portions 60 extending in the front-rear direction (Y1-Y2). Each support portion 60 is integrally formed from the inner side surface of the movable portion 2 and spaced from each support portion 56 of the fixed electrode 53 in the left-right direction (X1-X2). Further, as shown in FIG. 9A, a plurality of movable electrode elements 61 projecting short in the right direction (X2) from the right side surface of each support portion 60 alternate with the fixed electrode elements 57 in the front-rear direction (Y1-Y2) Is located in In FIG. 9A, only two movable electrode elements 61 are denoted by reference numerals.
　図９（ｂ）は可動部２が左方向（Ｘ１）に移動した状態を示す。これにより、可動電極子６１と固定電極子５７との間の対向面積が図９（ａ）の基準状態よりも減少し、静電容量が小さくなる。 FIG. 9B shows a state in which the movable portion 2 has moved in the left direction (X1). As a result, the facing area between the movable electrode element 61 and the fixed electrode element 57 is smaller than that in the reference state of FIG.
　なお図１に示す実施形態では、図１の左側に配置されたＸ方向検知部５０と右側に配置されたＸ方向検知部５１とでは、可動電極子６１と固定電極子５７との位置関係が逆になっており、Ｘ方向検知部５０にて静電容量が増加すれば、Ｘ方向検知部５１にて静電容量が減少し、また、Ｘ方向検知部５１にて静電容量が増加すれば、Ｘ方向検知部５２にて静電容量が減少する。これにより、Ｘ方向検知部５０により得られた静電容量変化と、Ｘ方向検知部５１により得られた静電容量変化により差動出力を得ることができる。 In the embodiment shown in FIG. 1, the positional relationship between the movable electrode 61 and the fixed electrode 57 is the difference between the X-direction detector 50 disposed on the left side of FIG. 1 and the X-direction detector 51 disposed on the right side. When the capacitance is increased in the X direction detection unit 50, the capacitance is decreased in the X direction detection unit 51, and the capacitance is increased in the X direction detection unit 51. For example, the capacitance decreases in the X-direction detection unit 52. As a result, a differential output can be obtained based on the change in capacitance obtained by the X-direction detection unit 50 and the change in capacitance obtained by the X-direction detection unit 51.
　図２は第２の実施形態における物理量センサ１９の平面図である。図２では、図１と異なって可動部２内にＸ方向検知部５０，５１が形成されておらず平面となっている。すなわち図１０の物理量センサは可動部２の高さ方向への変位のみを検出するものである。そのほか、図１と同じ符号が付された箇所は図１と同じ部分を指す。なお図２では各ばね部を簡易的に図示した。またばね部９，１７の形成位置は図１と異なった位置としたが、図１において図２のばね部９，１７の位置としてもよいし、図２において図１のばね部９，１７の位置としてもよい。 FIG. 2 is a plan view of the physical quantity sensor 19 in the second embodiment. In FIG. 2, unlike in FIG. 1, the X-direction detection units 50 and 51 are not formed in the movable unit 2 and are flat. That is, the physical quantity sensor of FIG. 10 detects only the displacement of the movable portion 2 in the height direction. In addition, portions denoted with the same reference numerals as in FIG. 1 indicate the same portions as in FIG. In addition, each spring part was illustrated in FIG. 2 simply. The positions where the spring portions 9 and 17 are formed are different from those in FIG. 1. However, the positions of the spring portions 9 and 17 in FIG. 2 may be used in FIG. It may be a position.
　図３は図２に示す物理量センサの静止状態における斜視図であり、図４、図５は物理量センサに高さ方向への加速度が作用した際の動作状態における斜視図である。なお図１の物理量センサにおいても図３ないし図５と同様の静止状態、動作状態となる。 3 is a perspective view of the physical quantity sensor shown in FIG. 2 in a stationary state, and FIGS. 4 and 5 are perspective views in an operating state when acceleration in the height direction is applied to the physical quantity sensor. Also in the physical quantity sensor of FIG. 1, the stationary state and the operating state are the same as those of FIGS.
　図３に示すように、物理量センサが静止状態のときに、表面全体と裏面全体が夫々、同一面上に位置しており、表面及び裏面から突出する部分がない図３に示す静止状態において可動部２と固定部３０との間の間隔は、例えば、１～５μｍ程度である。また、可動部２と対向部４０との間の間隔は、可動部２と固定部３０との間の間隔と同程度かあるいはそれよりも狭く設定される。 As shown in FIG. 3, when the physical quantity sensor is at rest, the entire front surface and the entire back surface are respectively located on the same plane, and there is no part projecting from the front surface and the back surface. The distance between the portion 2 and the fixing portion 30 is, for example, about 1 to 5 μm. Further, the distance between the movable portion 2 and the facing portion 40 is set to be approximately the same as or smaller than the distance between the movable portion 2 and the fixed portion 30.
　本実施形態の物理量センサは、外部から力（加速度等）が作用していないときに、ばね部の弾性復元力により、図３に示すように、全ての部分の表面が同一平面となった状態を維持している。 In the physical quantity sensor according to the present embodiment, when no force (such as acceleration) is applied from the outside, the surface of all the parts is in the same plane as shown in FIG. 3 by the elastic restoring force of the spring portion. Maintain.
　物理量センサに外部から例えば加速度が高さ方向に与えられると、加速度は、可動部２及び各アンカ部６，７に作用する。このとき、可動部２は慣性力によって絶対空間内で留まろうとし、その結果、各アンカ部６，７に対して可動部２が加速度の作用方向と逆の方向へ相対的に移動する。 When an external acceleration, for example, is applied to the physical quantity sensor from the outside, the acceleration acts on the movable portion 2 and the anchor portions 6 and 7. At this time, the movable portion 2 tries to stay in the absolute space by the inertial force, and as a result, the movable portion 2 moves relative to the anchor portions 6 and 7 in the direction opposite to the acting direction of the acceleration.
　図４は、アンカ部６，７、固定部３０及び対向部４０に対して下向きの加速度が作用したときの動作を示している。このとき、可動部２は慣性力により図３の静止状態の位置から上方向へ向けて変位すべく、第１支持部３，４及び第２支持部１３，１４が高さ方向に回動する。この回動動作時、各ばね部が捩れ変形する。 FIG. 4 shows an operation when downward acceleration is applied to the anchor portions 6 and 7, the fixing portion 30 and the facing portion 40. At this time, the first support portions 3 and 4 and the second support portions 13 and 14 rotate in the height direction so that the movable portion 2 is displaced upward from the position in the stationary state of FIG. 3 by inertia force. . At the time of this rotation operation, each spring portion is torsionally deformed.
　図４に示すように、各支持部３，４，１３，１４の脚部３ａ，４ａ，１３ａ，１４ａは下方に変位し、各脚部３ａ，４ａ，１３ａ，１４ａの先端は可動部２よりも下方に突出する。 As shown in FIG. 4, the legs 3a, 4a, 13a, 14a of each support 3, 4, 13, 14 are displaced downward, and the tips of the legs 3a, 4a, 13a, 14a are from the movable part 2. Also protrudes downward.
　脚部３ａ，４ａ，１３ａ，１４ａの突出量が大きくなると、図８に示すように、可動部２が固定部３０の表面３０ａに当接するよりも先に、脚部３ａ，４ａ，１３ａ，１４ａの先端部が対向部４０の表面（ストッパ面）４０ａに当接し、可動部２が図８の状態よりもさらに上方に変位できなくなり、可動部２の変位が抑制される。このように各脚部３ａ，４ａ，１３ａ，１４ａと対向部４０の表面（ストッパ面）４０ａとで可動部２の変位を抑制するストッパ機構が構成されている。 When the amount of protrusion of the legs 3a, 4a, 13a, 14a increases, as shown in FIG. 8, the legs 3a, 4a, 13a, 14a are earlier than the movable part 2 abuts on the surface 30a of the fixed part 30. The tip of the contact portion abuts on the surface (stopper surface) 40a of the facing portion 40, and the movable portion 2 can not be displaced further upward than the state of FIG. 8, and the displacement of the movable portion 2 is suppressed. As described above, the leg portions 3a, 4a, 13a, 14a and the surface (stopper surface) 40a of the facing portion 40 constitute a stopper mechanism for suppressing the displacement of the movable portion 2.
　図５は、アンカ部６，７、固定部３０及び対向部４０に対して上向きの加速度が作用したときの動作を示している。このとき、可動部２は慣性力により図３の静止状態の位置から下方向へ向けて変位すべく、第１支持部３，４及び第２支持部１３，１４が高さ方向に回動する。この回動動作時、各ばね部が捩れ変形する。 FIG. 5 shows an operation when an upward acceleration acts on the anchor portions 6 and 7, the fixing portion 30 and the opposing portion 40. At this time, the first support portions 3 and 4 and the second support portions 13 and 14 rotate in the height direction so that the movable portion 2 is displaced downward from the position in the stationary state of FIG. 3 by inertia force. . At the time of this rotation operation, each spring portion is torsionally deformed.
　図５に示すように、各支持部３，４，１３，１４の脚部３ａ，４ａ，１３ａ，１４ａは上方に変位し、各脚部３ａ，４ａ，１３ａ，１４ａの先端は、可動部２よりも上方に突出する。 As shown in FIG. 5, the legs 3a, 4a, 13a, 14a of the support portions 3, 4, 13, 14 are displaced upward, and the tips of the legs 3a, 4a, 13a, 14a are movable portions 2 Project more upwards.
　本実施形態では、可動部２と、対向部４０に設けられた固定電極４１との間の静電容量変化により、加速度等の物理量を検出することが可能となっている。 In the present embodiment, it is possible to detect a physical quantity such as acceleration based on a change in electrostatic capacitance between the movable portion 2 and the fixed electrode 41 provided in the facing portion 40.
　本実施形態の可動部２の支持機構により可動部２を高さ方向（Ｚ）に効果的に平行移動させることが出来る。 The movable portion 2 can be effectively translated in the height direction (Z) by the support mechanism of the movable portion 2 of the present embodiment.
　特に本実施形態によれば、高さ方向（Ｚ）への検出モードと、検出モード以外のモードとの固有振動数の差を効果的に大きくできる。ここで、「検出モード以外のモード」には、前後方向（Ｙ１－Ｙ２）への振動、前後方向や左右方向、さらには前後方向と左右方向の双方に対して斜めに傾く対角線方向を軸とした回転モード、面内回転モード等が含まれる。このように高さ方向（Ｚ）への検出モードと、検出モード以外のモードとの固有振動数の差を効果的に大きくできるから、検出モード時に、検出モード以外のモードが加わっても、可動部２を高さ方向に安定して平行移動させることができる。 In particular, according to the present embodiment, the difference between the natural frequency of the detection mode in the height direction (Z) and the modes other than the detection mode can be effectively increased. Here, in the “mode other than detection mode”, vibration in the front-rear direction (Y1-Y2), a diagonal direction inclined obliquely to both the front-rear direction and the left-right direction, and further both the front-rear direction and the left-right direction Rotation mode, in-plane rotation mode, etc. are included. As described above, since the difference between the natural frequency of the detection mode in the height direction (Z) and the modes other than the detection mode can be effectively increased, the movable mode can be moved even if a mode other than the detection mode is added in the detection mode. The part 2 can be stably translated in the height direction.
　また、本実施形態では、大きな加速度が作用した場合等に、各支持部３，４，１３，１４の各脚部３ａ，４ａ，１３ａ，１４ａを対向部４０の表面４０ａに当接させることができ、これにより可動部２の変位を抑制できる。そして本実施形態では、脚部３ａ，４ａ、１３ａ、１４ａの先端（対向部４０の表面４０ａとの当接部）が可動部２の四隅付近に位置するため、図８の当接状態において、可動部２の姿勢を安定にできる。 Further, in the present embodiment, each leg portion 3a, 4a, 13a, 14a of each support portion 3, 4, 13, 14 may be brought into contact with the surface 40a of the opposing portion 40 when a large acceleration acts. Thus, the displacement of the movable portion 2 can be suppressed. And in this embodiment, since the tips of the legs 3a, 4a, 13a, 14a (the contact parts with the surface 40a of the facing part 40) are located near the four corners of the movable part 2, in the contact state of FIG. The posture of the movable portion 2 can be stabilized.
　また本実施形態では、シリコン基板８の中央領域に可動部２を形成し、可動部２の側方に支持部３，４，１３，１４を設けた構成としたことで、可動部２の面積を広くできる。よって固定電極４１との間で生じる静電容量を大きくできる。また図８のように、各脚部３ａ，４ａ、１３ａ、１４ａの先端が対向部４０の表面４０ａに当接するため、脚部により、簡単なストッパ兼スティッキング防止構造を実現できる。 Further, in the present embodiment, the movable portion 2 is formed in the central region of the silicon substrate 8, and the supporting portions 3, 4, 13 and 14 are provided on the side of the movable portion 2. Can be Therefore, the capacitance generated between the fixed electrode 41 and the fixed electrode 41 can be increased. Further, as shown in FIG. 8, since the tips of the legs 3a, 4a, 13a and 14a abut on the surface 40a of the facing portion 40, the leg can realize a simple stopper and sticking prevention structure.
　なお図８では、対向部４０の表面４０ａが平坦面となっているが、例えば、各脚部３ａ，４ａ、１３ａ、１４ａの先端が当接する位置の表面４０ａを突出させて可動部２の高さ方向（Ｚ）への変位量を規制したり、あるいは表面４０ａからの突起の面積を小さくするなどして、各脚部と対向部４０との接触面積がより小さくなるように構成することもできる。
　以上により高感度で検出安定性に優れた物理量センサにできる。 In FIG. 8, the surface 40 a of the facing portion 40 is a flat surface, but, for example, the height of the movable portion 2 is increased by projecting the surface 40 a at a position where the tips of the legs 3 a, 4 a, 13 a, 14 a abut. Alternatively, the contact area between each leg and the opposing portion 40 may be reduced by restricting the amount of displacement in the longitudinal direction (Z) or reducing the area of the protrusion from the surface 40a. it can.
Thus, a physical quantity sensor with high sensitivity and excellent detection stability can be obtained.
　また本実施形態では図１，図２，図６に示すように、可動部２の前方（Ｙ２）及び後方（Ｙ１）に形成された夫々の第１の支持部３，４と第２の支持部１３，１４同士が連結ばね２１によって連結されている。連結ばね２１を設けることで、連結ばね２１により連結された第１の支持部３，４と、第２の支持部１３，１４との間で回動状態が同等となるように規制でき、第１の支持部３，４に設けられた第１の脚部３ａ，４ａと、第２の支持部１３，１４に設けられた第２の脚部１３ａ，１４ａとを可動部２に対し上方あるいは下方の同方向に突出量のばらつきを小さく安定して突出させることができる。 In the embodiment, as shown in FIGS. 1, 2 and 6, the first support portions 3 and 4 and the second support formed on the front (Y2) and the rear (Y1) of the movable portion 2 respectively. The portions 13 and 14 are connected by a connecting spring 21. By providing the connection spring 21, it is possible to restrict the rotational states of the first support portions 3 and 4 connected by the connection spring 21 to be equal between the second support portions 13 and 14. The first legs 3a and 4a provided in the first and second support portions 3 and 4 and the second legs 13a and 14a provided in the second support portions 13 and 14 are located above the movable portion 2 or The variation of the amount of protrusion can be made small and stable in the same direction below.
　また本実施形態では、図１，図２等に示すように一対の第１の支持部３，４が可動部２の右方側（Ｘ２）にて連結されて一体化しており、また、一対の第２の支持部１３，１４が可動部２の左方側（Ｘ１）にて連結されて一体化している。これにより、一対の第１の支持部３，４及び一対の第２の支持部１３，１４を夫々、一緒に回動させることができ、これにより可動部２を高さ方向に、より安定して平行移動させることができ、検出安定性をより効果的に向上させることができる。 Further, in the present embodiment, as shown in FIGS. 1 and 2, etc., the pair of first support portions 3 and 4 are connected and integrated on the right side (X2) of the movable portion 2, and the pair The second support portions 13 and 14 are integrally connected at the left side (X1) of the movable portion 2. As a result, the pair of first support portions 3 and 4 and the pair of second support portions 13 and 14 can be rotated together, thereby making the movable portion 2 more stable in the height direction. Parallel movement, and detection stability can be more effectively improved.
　また本実施形態では、可動部２の後方（Ｙ１）では、第１の支持部４が第２の支持部１４よりも外側に位置し、可動部２の前方（Ｙ２）では、第２の支持部１３が第１の支持部３よりも外側に位置している。上記したように、可動部２の後方（Ｙ１）に位置する第１の支持部４及び第２の支持部１４と、可動部２の前方（Ｙ２）に位置する第１の支持部３及び第２の支持部１３とでは互いに可動部２（シリコン基板８）の中心Ｏを中心軸として１８０度回転させた形状と一致している。これにより、シリコン基板８内に可動部２と、可動部２の両側に、アンカ部６，７、一対の第１の支持部３，４及び一対の第２の支持部１３，１４とを効率良く配置でき、物理量センサの小型化を実現できる。 In the present embodiment, the first support portion 4 is positioned outside the second support portion 14 at the rear (Y1) of the movable portion 2 and the second support at the front (Y2) of the movable portion 2 The portion 13 is located outside the first support portion 3. As described above, the first support portion 4 and the second support portion 14 located behind the movable portion 2 (Y1), and the first support portion 3 and the first support portion located forward of the movable portion 2 (Y2) The second support portion 13 and the second support portion 13 correspond to a shape rotated 180 degrees around the center O of the movable portion 2 (silicon substrate 8). As a result, the movable portion 2 in the silicon substrate 8, and the anchor portions 6 and 7, the pair of first support portions 3 and 4, and the pair of second support portions 13 and 14 on both sides of the movable portion 2 It can be arranged well and the physical quantity sensor can be miniaturized.
　また図１に示す実施形態では、可動部２内にＸ方向検知部５０，５１を設けたことで、可動部２の高さ方向（Ｚ）への変位の検知と、左右方向（Ｘ１－Ｘ２）への変位の検知の双方を小型の物理量センサにより得ることができる。なお本実施形態では、可動部２と各支持部３，４，１３，１４との間を連結するばね部９，１７が前後方向（Ｙ１－Ｙ２）に細長く形成されており、可動部２が前後方向に変位しにくくなっている。したがって図１に示す実施形態の物理量センサ１によれば、可動部２の高さ方向の変位と左右方向（Ｘ１－Ｘ２）の変位を安定して検知することが可能になっている。 Further, in the embodiment shown in FIG. 1, by providing the X-direction detection units 50 and 51 in the movable unit 2, detection of displacement of the movable unit 2 in the height direction (Z) and horizontal direction (X1-X2 Both of the detection of the displacement to) can be obtained by a small physical quantity sensor. In the present embodiment, the spring portions 9 and 17 connecting the movable portion 2 and the support portions 3, 4, 13 and 14 are formed to be elongated in the front-rear direction (Y 1 -Y 2), and the movable portion 2 is It is difficult to displace in the back and forth direction. Therefore, according to the physical quantity sensor 1 of the embodiment shown in FIG. 1, it is possible to stably detect the displacement in the height direction of the movable portion 2 and the displacement in the left-right direction (X1-X2).
　また、可動部２内にＸ方向検知部５０，５１を設けたことで、可動部２の高さ方向への振動性能を損なうことがない。後述する実験では、検出モード以外のモードの固有振動数と高さ方向への検出モードの固有振動数との差を広げることができ、可動部２を安定して高さ方向や左右方向に変位させることができ、優れた検出安定性を得ることができる。 Further, by providing the X direction detection units 50 and 51 in the movable unit 2, the vibration performance in the height direction of the movable unit 2 is not impaired. In the experiment described later, it is possible to widen the difference between the natural frequency of modes other than the detection mode and the natural frequency of the detection mode in the height direction, and the movable part 2 is stably displaced in the height direction or the lateral direction. It is possible to obtain excellent detection stability.
　また図１０は可動電極子６１及びＺ方向検知部としての固定電極４１との部分縦断面図である。図１０には一つの可動電極子６１のみを図示した。図１０に示すように可動電極子６１の下面（端部）６１ａから所定のギャップＧを介して対向する固定電極４１に向けて電界Ｅが可動電極子６１の幅よりも広がって発生していることがわかる。このため図１や図９に示すように可動部２内にＸ方向検知部５０，５１を設けることで微小隙間が可動部２内に形成されるが、前記微小隙間内では、電界Ｅが固定電極４１に向けて広がって生じているために、可動部２内にＸ方向検知部が形成されていない形態と比べて、静電容量の低下を低く抑えることができ、あるいは、可動部２内にＸ方向検知部が形成されていない形態とほぼ同等の静電容量を得ることができる。 FIG. 10 is a partial longitudinal cross-sectional view of the movable electrode 61 and the fixed electrode 41 as a Z direction detection unit. Only one movable electrode 61 is shown in FIG. As shown in FIG. 10, the electric field E is generated so as to be wider than the width of the movable electrode 61 from the lower surface (end portion) 61a of the movable electrode 61 to the fixed electrode 41 opposed via the predetermined gap G. I understand that. Therefore, as shown in FIG. 1 and FIG. 9, a minute gap is formed in the movable portion 2 by providing the X direction detecting portions 50 and 51 in the movable portion 2, but the electric field E is fixed in the minute gap. Since the expansion occurs toward the electrode 41, the decrease in electrostatic capacitance can be suppressed to a low level as compared with the embodiment in which the X-direction detection unit is not formed in the movable unit 2, or It is possible to obtain substantially the same capacitance as in the embodiment in which the X direction detection unit is not formed.
　またＸ方向検知部５０，５１を平行平板式でなく、面積変化式による静電容量変化を捉えることで、左右方向（Ｘ１－Ｘ２）の変位に対する静電容量の変化の出力を良好な線形性を有した状態で得られるため、高い検出精度を得ることができ、さらに、左右方向（Ｘ１－Ｘ２）への有効検出範囲（ダイナミックレンジ）を広くできる。 Moreover, the output of the change of the capacitance with respect to the displacement in the left-right direction (X1-X2) is good linearity by capturing the capacitance change by the area change type instead of the parallel plate type of the X direction detection units 50 and 51 Therefore, high detection accuracy can be obtained, and further, the effective detection range (dynamic range) in the left-right direction (X1-X2) can be broadened.
　特に、Ｘ方向検知部５０，５１では固定電極５３と可動電極５２において複数本の支持部５６，６０を設け、各支持部５６，６０から複数本の固定電極子５７及び複数本の可動電極子６１を設けることで、可動部２が左右方向（Ｘ１－Ｘ２）に移動した際の面積変化領域を増やすことができ、左右方向への検出感度を向上させることができる。 In particular, in the X direction detection units 50 and 51, a plurality of support portions 56 and 60 are provided in the fixed electrode 53 and the movable electrode 52, and from the support portions 56 and 60, a plurality of fixed electrode elements 57 and a plurality of movable electrode elements By providing 61, it is possible to increase the area change area when the movable portion 2 moves in the left-right direction (X1-X2), and it is possible to improve the detection sensitivity in the left-right direction.
　本実施形態では、可動部２と、対向部４０に設けられた固定電極４１との間の静電容量変化により、加速度等の物理量を検出することが可能であるが、検知部の構成は静電容量式に限定するものではない。ただし静電容量式としたことで簡単で且つ高精度な検知部の構成を実現できる。 In the present embodiment, it is possible to detect a physical quantity such as acceleration by a change in electrostatic capacitance between the movable portion 2 and the fixed electrode 41 provided in the facing portion 40, but the configuration of the detection portion is static. It is not limited to the capacitance type. However, by using the capacitance type, the configuration of a simple and highly accurate detection unit can be realized.
　本実施形態は加速度センサのみならず角速度センサ、衝撃センサ等、物理量センサ全般に適用可能である。 The present embodiment is applicable not only to acceleration sensors but also to physical quantity sensors in general, such as angular velocity sensors and impact sensors.
（実験１：実施例と比較例における複数モードでの固有振動数の実験）
　図１１ないし図１３は比較例の物理量センサの構成である。図１１は平面図、図１２、図１３は斜視図である。 (Experiment 1: Experiment of natural frequency in plural modes in the example and the comparative example)
11 to 13 show the configuration of the physical quantity sensor of the comparative example. FIG. 11 is a plan view, and FIGS. 12 and 13 are perspective views.
　比較例に示す物理量センサ１００は、実施例（図１）の物理量センサ１と異なって可動部１０１の内側にアンカ部１０２～１０４及び支持部１０５～１０８が設けられている。可動部１０１、アンカ部１０２～１０４及び支持部１０５～１０８は夫々分離して形成されている。また符号１０９～１２０はばね部である。 Unlike the physical quantity sensor 1 of the embodiment (FIG. 1), the physical quantity sensor 100 shown in the comparative example is provided with anchor parts 102 to 104 and support parts 105 to 108 inside the movable part 101. The movable portion 101, the anchor portions 102 to 104 and the support portions 105 to 108 are separately formed. Further, reference numerals 109 to 120 denote spring portions.
　図１１に示すように、支持部１０５，１０７には夫々、脚部１０５ａ，１０７ａが設けられている。 As shown in FIG. 11, leg portions 105a and 107a are provided on the support portions 105 and 107, respectively.
　図１２は静止状態であり、高さ方向に加速度が作用すると可動部１０１が高さ方向に変位し、図１３に示すように脚部１０５ａ，１０７ａが可動部１０１とは逆方向に変位して脚部１０５ａ，１０７ａの先端が突出する。 FIG. 12 shows the stationary state, and when acceleration acts in the height direction, the movable portion 101 is displaced in the height direction, and as shown in FIG. 13, the leg portions 105a and 107a are displaced in the opposite direction to the movable portion 101. The tips of the legs 105a and 107a project.
　図１に示す実施例１と、上記した比較例を用いて、異なる複数モードにおける固有振動数（ＫＨｚ）を求めた。 The natural frequency (KHz) in different modes was determined using Example 1 shown in FIG. 1 and the comparative example described above.
　実施例１及び比較例におけるモード１は高さ方向（Ｚ）への検出モードである。実施例１におけるモード２は左右方向（Ｘ１－Ｘ２）への検出モードである。また実施例１におけるモード３～モード６は、検出モード以外のモードであり、前後方向（Ｙ１－Ｙ２）への振動モード、前後方向及び左右方向を軸とした回転モード、面内回転モードである。実施例１のモード３～モード６については、固有振動数が低いモード順に並べた。 Mode 1 in Example 1 and Comparative Example is a detection mode in the height direction (Z). Mode 2 in the first embodiment is a detection mode in the left-right direction (X1-X2). In addition, modes 3 to 6 in the first embodiment are modes other than the detection mode, and are a vibration mode in the back and forth direction (Y1-Y2), a rotation mode centering on the back and forth direction and the left and right direction . The mode 3 to mode 6 of the first embodiment are arranged in the order of modes having lower natural frequencies.
　また、比較例におけるモード２～モード６は、検出モード以外のモードであり、左右方向（Ｘ１－Ｘ２）及び前後方向（Ｙ１－Ｙ２）への振動モード、前後方向及び左右方向を軸とした回転モード、面内回転モードである。比較例のモード２～モード６については、固有振動数が低いモード順に並べた。 Further, mode 2 to mode 6 in the comparative example are modes other than the detection mode, and vibration modes in the lateral direction (X1-X2) and the longitudinal direction (Y1-Y2) and rotation around the longitudinal direction and the lateral direction Mode, in-plane rotation mode. The mode 2 to mode 6 of the comparative example are arranged in the order of modes with low natural frequency.
　実施例１は、高さ方向（Ｚ）及び左右方向（Ｘ）への可動部の変位を検出する構成である。図１４に示すように、比較例においても、検出モード以外であるモード２～モード６での固有振動数は、検出モードであるモード１よりも高くなり、固有振動数差を得ることができるとわかった。よって比較例の構成においても、可動部の高さ方向への変位を適切に検出することができる。ただし実施例１のほうが比較例よりも検出モード以外であるモード３～モード６での固有振動数は高くなり、検出モードとの固有振動数差を広げることができるとわかった。 The first embodiment is configured to detect the displacement of the movable portion in the height direction (Z) and the left and right direction (X). As shown in FIG. 14, also in the comparative example, the natural frequencies in modes 2 to 6 other than the detection mode are higher than those in mode 1 which is the detection mode, and it is possible to obtain the natural frequency difference. all right. Therefore, also in the configuration of the comparative example, the displacement in the height direction of the movable portion can be appropriately detected. However, it was found that the natural frequencies in mode 3 to mode 6 other than the detection mode are higher in the example 1 than in the comparative example, and the natural frequency difference with the detection mode can be broadened.
　また、実施例１では、左右方向（Ｘ）への検出モードであるモード２と、検出モード以外であるモード３～モード６との固有振動数差を、モード１の場合と同様に大きくすることができた。 In the first embodiment, the natural frequency difference between mode 2 which is the detection mode in the left-right direction (X) and mode 3 to mode 6 other than the detection mode should be increased as in the case of mode 1. It was possible.
　このように実施例１では、検出モードと検出モード以外のモードとの固有振動数差を大きくでき、優れた検出安定性を得ることができるとわかった。 As described above, in Example 1, it was found that the natural frequency difference between the detection mode and the modes other than the detection mode can be increased, and excellent detection stability can be obtained.
　続いて図１０に示す実施例２（高さ方向検知のみ）と、上記した比較例を用いて、異なる複数モードにおける固有振動数（ＫＨｚ）を求めた。 Subsequently, natural frequencies (KHz) in different modes were obtained using Example 2 (only in the height direction detection) shown in FIG. 10 and the above-described comparative example.
　実施例２及び比較例におけるモード１は高さ方向（Ｚ）への検出モードである。また実施例２及び比較例におけるモード２～モード６は、検出モード以外のモードであり、左右方向（Ｘ１－Ｘ２）及び前後方向（Ｙ１－Ｙ２）への振動モード、前後方向及び左右方向を軸とした回転モード、面内回転モードである。実施例２及び比較例のモード２～モード６については、固有振動数が低いモード順に並べた。 Mode 1 in Example 2 and Comparative Example is a detection mode in the height direction (Z). In addition, modes 2 to 6 in the second embodiment and the comparative example are modes other than the detection mode, and vibration modes in the left-right direction (X1-X2) and the front-rear direction (Y1-Y2) And the in-plane rotation mode. The mode 2 to mode 6 of the embodiment 2 and the comparative example are arranged in the order of modes having low natural frequencies.
　図１５に示す比較例の結果は図１４と同じである。図１５に示すように、実施例２と比較例とを対比すると、検出モード以外であるモード２～モード６での固有振動数はいずれも実施例１のほうが高いことがわかった。この結果、これら検出モード以外のモード２～６と、高さ方向の検出モードであるモード１との固有振動数差は、実施例２のほうが比較例よりも大きくなることがわかった。 The result of the comparative example shown in FIG. 15 is the same as FIG. As shown in FIG. 15, when Example 2 and Comparative Example are compared, it was found that all of the natural frequencies in Mode 2 to Mode 6 other than the detection mode are higher in Example 1. As a result, it was found that the natural frequency difference between the modes 2 to 6 other than these detection modes and the mode 1 which is the detection mode in the height direction is larger in the example 2 than in the comparative example.
　このように実施例２では、検出モードと検出モード以外のモードとの固有振動数差を大きくでき、優れた検出安定性を得ることができるとわかった。 As described above, in Example 2, it was found that the natural frequency difference between the detection mode and the modes other than the detection mode can be increased, and excellent detection stability can be obtained.
（実験２：実施例１におけるギャップと静電容量の実験）
　実験では図１に示す実施例１（高さ方向及び左右方向の検知部を備える）の物理量センサを用い、図１０に示すギャップＧを変化させてＺ方向検知部における静電容量を求めた。また図１０に示す実施例２（高さ方向の検知部のみ備える）の物理量センサを用い、図１０に示すギャップＧを変化させてＺ方向検知部における静電容量を求めた。 (Experiment 2: Experiment of gap and capacitance in Example 1)
In the experiment, using the physical quantity sensor of Example 1 (provided with detection units in the height direction and the left and right direction) shown in FIG. 1, the gap G shown in FIG. 10 was changed to obtain the capacitance in the Z direction detection unit. Further, using the physical quantity sensor of Example 2 (only the detection unit in the height direction) shown in FIG. 10, the gap G shown in FIG. 10 was changed to obtain the capacitance in the Z direction detection unit.
　その実験結果が図１６に示されている。実施例１と実施例２との静電容量差は非常に小さく、実施例１のように、可動部内にＸ方向検知部を設けても、高さ方向（Ｚ）への検知を高感度で行うことが可能であるとわかった。 The experimental results are shown in FIG. The electrostatic capacity difference between the first embodiment and the second embodiment is very small, and even if the X direction detection unit is provided in the movable portion as in the first embodiment, detection in the height direction (Z) is highly sensitive. It turned out that it was possible to do.
　電界ベクトルを調べてみると、図１０のように電界が櫛歯状電極の下面から固定電極の方向に向って広がっていることがわかった。この結果、可動部２内にＸ方向検知部を設けることで微小隙間が形成されても、前記微小隙間内は櫛歯状電極の下面から広がった電界が作用して電荷密度を上げることができ、図１６のようにＸ方向検知部を備えない実施例２と大差ない静電容量が得られたものと考えられる。 When the electric field vector was examined, it was found that the electric field spreads from the lower surface of the comb electrode to the direction of the fixed electrode as shown in FIG. As a result, even if a minute gap is formed by providing the X-direction detection portion in the movable portion 2, an electric field spread from the lower surface of the comb-like electrode acts in the minute gap to increase the charge density. It is considered that a capacitance similar to that of the second embodiment having no X-direction detection unit as shown in FIG. 16 is obtained.
　ただしＸ方向検知部の構成としては、並行平板型などとすると可動部２内に形成される空間が大きくなったり、また前記空間内を電界の広がりでカバーしきれないことがある。したがって、図１，図９に示したように、Ｘ方向検知部の可動電極側と固定電極側とで多数の櫛歯状電極が微小隙間を空けて対向し、可動部２が左右方向に可動したときに櫛歯状電極間の対向面積の変化により静電容量が変化する構成とすることが、高感度にでき好適である。 However, as the configuration of the X-direction detection unit, if a parallel plate type or the like is used, the space formed in the movable portion 2 may be large, or the space may not be covered by the spread of the electric field. Therefore, as shown in FIGS. 1 and 9, a large number of comb-like electrodes face each other with a minute gap between the movable electrode side and the fixed electrode side of the X direction detection unit, and the movable portion 2 is movable in the lateral direction At this time, it is preferable that the electrostatic capacity changes due to a change in the facing area between the comb-like electrodes, because high sensitivity can be achieved.
１、１９　物理量センサ
２　可動部
３、４　第１の支持部
３ａ、４ａ　第１の脚部
６、７　第１のアンカ部
８　シリコン基板
９、１１，１５、１７　ばね部
１３、１４　第２の支持部
１３ａ、１４ａ　第２の脚部
２１　連結ばね
３０　固定部
４０　対向部
４１、５３　固定電極
５０、５１　Ｘ方向検知部
５２　可動電極
５４　アンカ部
５７　固定電極子
６１　可動電極子 1, 19 physical quantity sensor 2 movable part 3, 4 first support part 3a, 4a first leg 6, 7 first anchor 8 silicon substrate 9, 11, 15, 17 spring 13, 14 second Support part 13a, 14a Second leg 21 Connection spring 30 Fixing part 40 Counterpart 41, 53 Fixing electrode 50, 51 X direction detection part 52 Movable electrode 54 Anchor part 57 Fixed electrode 61 61 Movable electrode

Claims (6)

  1. 　高さ方向に変位可能な可動部と、前記可動部の変位を検知するためのＺ方向検知部とを有して構成される物理量センサにおいて、
    　シリコン基板には、固定支持されるアンカ部、前記可動部、及び前記アンカ部と前記可動部とにばね部を介して回動自在に連結された支持部が夫々分離して形成されており、
    　前記シリコン基板の中央領域に前記可動部が配置され、前記可動部のＹ１－Ｙ２方向の両側に一対の第１のアンカ部が配置され、前記一対の第１のアンカ部に夫々、前記Ｙ１－Ｙ２方向に対して直交するＸ１－Ｘ２方向に延出する第１の支持部が回動自在に連結され、
    　前記一対の第１のアンカ部に対して前記Ｘ１－Ｘ２方向に並設された一対の第２のアンカ部が配置され、前記一対の第２のアンカ部に夫々、前記Ｘ１－Ｘ２方向に延出する第２の支持部が回動自在に連結されるとともに前記第１の支持部と並設されており、
    　各支持部には、前記支持部が回動して前記可動部が高さ方向に変位したときに前記可動部の変位方向に対し逆方向に変位する脚部が設けられており、
    　一対の前記第１の支持部に夫々設けられた第１の脚部は、前記第１のアンカ部からＸ１方向に向けて形成されており、一対の前記第２の支持部に夫々設けられた第２の脚部は、前記第２のアンカ部からＸ２方向に向けて形成されていることを特徴とする物理量センサ。     In a physical quantity sensor configured to include a movable portion displaceable in a height direction and a Z direction detection portion for detecting displacement of the movable portion,
    On the silicon substrate, an anchor portion fixedly supported, the movable portion, and a support portion rotatably connected to the anchor portion and the movable portion via a spring portion are separately formed, respectively.
    The movable portion is disposed in the central region of the silicon substrate, and a pair of first anchor portions are disposed on both sides of the movable portion in the Y1-Y2 direction, and the first anchor portions are respectively disposed in the Y1- A first support portion extending in an X1-X2 direction orthogonal to the Y2 direction is rotatably connected;
    A pair of second anchor portions juxtaposed in the X1-X2 direction is arranged with respect to the pair of first anchor portions, and the pair of second anchor portions respectively extend in the X1-X2 direction A second supporting portion to be released is rotatably connected and juxtaposed with the first supporting portion;
    Each support portion is provided with a leg portion which is displaced in a direction opposite to the displacement direction of the movable portion when the support portion is rotated to displace the movable portion in the height direction.
    The first legs respectively provided on the pair of first support portions are formed in the X1 direction from the first anchor portion, and provided on the pair of second support portions respectively. The physical quantity sensor characterized in that the second leg portion is formed in the X2 direction from the second anchor portion.
  2. 　前記第１のアンカ部と前記第２のアンカ部との間には、前記第１の支持部と前記第２の支持部との間を連結する連結ばねが設けられている請求項１記載の物理量センサ。 The connection spring which connects between the said 1st support part and the said 2nd support part is provided between the said 1st anchor part and the said 2nd anchor part. Physical quantity sensor.
  3. 　前記一対の第１の支持部は、前記可動部のＸ２側にて連結されて一体化しており、前記一対の前記第２の支持部は、前記可動部のＸ１側にて連結されて一体化している請求項１又は２に記載の物理量センサ。 The pair of first support portions are connected and integrated on the X2 side of the movable portion, and the pair of second support portions are connected and integrated on the X1 side of the movable portion. The physical quantity sensor according to claim 1 or 2.
  4. 　前記可動部のＹ１側では、前記第１の支持部が前記第２の支持部よりも外側に位置しており、前記可動部のＹ２側では、前記第２の支持部が前記第１の支持部よりも外側に位置している請求項３記載の物理量センサ。 At the Y1 side of the movable portion, the first support portion is positioned outside the second support portion, and at the Y2 side of the movable portion, the second support portion is the first support. The physical quantity sensor according to claim 3, which is located outside the portion.
  5. 　前記可動部内には、前記可動部のＸ１－Ｘ２方向への変位を検知するためのＸ方向検知部が形成される請求項１ないし４のいずれか１項に記載の物理量センサ The physical quantity sensor according to any one of claims 1 to 4, wherein an X-direction detection unit for detecting the displacement of the movable unit in the X1-X2 direction is formed in the movable unit.
  6. 　前記Ｘ方向検知部は、前記可動部と一体に形成されたＸ検知可動電極と、前記可動部と分離して形成されたＸ検知固定電極とを有し、前記Ｘ検知可動電極と前記Ｘ検知固定電極とが前記シリコン基板を加工して形成されたものであり、前記Ｘ検知可動電極及び前記Ｘ検知固定電極には夫々、Ｙ１－Ｙ２方向にて間隔を空けて対向する複数の電極子がＸ１－Ｘ２方向に列を成して構成されている請求項５記載の物理量センサ。 The X direction detection unit has an X detection movable electrode integrally formed with the movable portion, and an X detection fixed electrode formed separately from the movable portion, and the X detection movable electrode and the X detection A fixed electrode is formed by processing the silicon substrate, and a plurality of electrodes facing the X detection movable electrode and the X detection fixed electrode at intervals in the Y1-Y2 direction are respectively formed on the X detection movable electrode and the X detection fixed electrode. The physical quantity sensor according to claim 5, wherein the physical quantity sensor is configured to form a line in the X1-X2 direction.
PCT/JP2013/050262 2012-01-11 2013-01-10 Physical quantity sensor WO2013105591A1 (en)

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Citations (4)

* Cited by examiner, † Cited by third party
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JP2007530914A (en) * 2003-07-08 2007-11-01 フリースケール セミコンダクター インコーポレイテッド Single proof mass, triaxial micro electromechanical transducer
WO2009125510A1 (en) * 2008-04-11 2009-10-15 三菱電機株式会社 Acceleration sensor
WO2010001947A1 (en) * 2008-07-04 2010-01-07 アルプス電気株式会社 Capacitance detection type movable sensor
WO2010140574A1 (en) * 2009-06-03 2010-12-09 アルプス電気株式会社 Physical quantity sensor

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2007530914A (en) * 2003-07-08 2007-11-01 フリースケール セミコンダクター インコーポレイテッド Single proof mass, triaxial micro electromechanical transducer
WO2009125510A1 (en) * 2008-04-11 2009-10-15 三菱電機株式会社 Acceleration sensor
WO2010001947A1 (en) * 2008-07-04 2010-01-07 アルプス電気株式会社 Capacitance detection type movable sensor
WO2010140574A1 (en) * 2009-06-03 2010-12-09 アルプス電気株式会社 Physical quantity sensor

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