JP2016174305A - Vibrator, electronic apparatus and moving body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vibrator capable of improving a Q value, and an electronic apparatus and a moving body having the vibrator.SOLUTION: The vibrator includes: a base 531; a plurality of vibration parts 532 extending from the base 531 to mutually different directions; and a connection 533 having a through hole and connecting between two mutually adjacent vibration parts 532. The vibration part 532 is a movable electrode facing a lower electrode 51 disposed on a substrate 2.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a vibrator, an electronic device, and a moving body.

  A MEMS structure manufactured using MEMS (Micro Electro Mechanical Systems) technology is applied to various structures (for example, vibrators, filters, sensors, motors, etc.) having movable parts. The MEMS vibrator is easier to manufacture by incorporating a semiconductor circuit than a vibrator or resonator using a crystal or a dielectric, and is advantageous from the viewpoint of miniaturization and high functionality. is there.

  For example, the MEMS vibrator described in Patent Literature 1 is separated from the substrate by the substrate, the lower electrode and the fixing portion provided on the main surface of the substrate, the supporting portion extending from the fixing portion, and the supporting portion. A supported upper electrode. Here, the upper electrode has a cross shape having four vibrating portions extending in different directions from the central portion, and the central portion is supported by the support portion. In such a MEMS vibrator, the vibration node of the upper electrode can be supported by the support part, and as a result, vibration leakage can be suppressed.

  However, the MEMS vibrator described in Patent Document 1 has a problem that the Q value cannot be sufficiently increased due to the influence of thermoelastic loss between two adjacent vibrating parts of the upper electrode.

Japanese Patent Application Laid-Open No. 2014-187777

  An object of the present invention is to provide a vibrator capable of improving the Q value, and to provide an electronic device and a moving body including the vibrator.

Such an object is achieved by the present invention described below.
[Application Example 1]
The vibrator of the present invention includes a base,
A plurality of vibrating portions extending in different directions from the base portion;
Connecting the two vibrating parts adjacent to each other, and a connecting part having a through hole or a recess,
It is characterized by providing.

  According to such a vibrator, since the connecting portions connect the vibrating portions adjacent to each other, it is possible to reduce the thermoelastic loss that occurs between the two vibrating portions. Therefore, the Q value can be improved. And since the connection part has a through-hole or a recessed part, the excessive raise of the resonant frequency of a vibration part can be reduced.

  For this reason, the Q value can be improved while reducing the resonance frequency of the vibration part.

[Application Example 2]
In the vibrator of the present invention, a substrate,
A support part connecting the substrate and the base part;
It is preferable to provide.
As a result, the vibration part can be supported to be vibrated with respect to the substrate via the base.

[Application Example 3]
In the vibrator according to the aspect of the invention, it is preferable that at least a part of the support portion is between the substrate and the base portion.

  Thereby, a clearance allowing vibration of the vibration part can be easily formed between the vibration part and the substrate, and a vibrator having stable vibration characteristics can be realized.

[Application Example 4]
In the vibrator according to the aspect of the invention, it is preferable that the support portion is connected to the connection portion.

  As a result, it is possible to support the vibration part at a site serving as a vibration node, and as a result, it is possible to reduce a decrease in Q value due to vibration leakage.

[Application Example 5]
In the vibrator according to the aspect of the invention, the connection portion includes a beam portion connecting the two vibration portions.
It is preferable that the through hole or the concave portion is disposed between the beam portion and the two vibration portions.

  Thereby, the balance between the reduction of the thermoelastic loss and the reduction of the resonance frequency of the vibration part can be made excellent.

[Application Example 6]
In the vibrator of the present invention, when the width of the portion where the beam portion and the vibration portion are connected is a, and the width of the through hole or the recess along the extending direction of the vibration portion is b. ,
It is preferable to satisfy the relationship of 0.6 ≦ b / a ≦ 1.6.

  Thereby, the balance between the reduction of the thermoelastic loss and the reduction of the resonance frequency of the vibration part can be made excellent.

[Application Example 7]
The vibrator according to the present invention includes a substrate-side electrode disposed on the substrate,
It is preferable that the vibration part has a movable electrode facing the substrate side electrode.
Thereby, an electrostatic drive type vibrator can be realized.

[Application Example 8]
An electronic apparatus according to the present invention includes the vibrator according to the present invention.

  Thereby, an electronic device provided with a vibrator having an excellent Q value at a low frequency can be provided.

[Application Example 9]
The moving body of the present invention includes the vibrator of the present invention.

  Accordingly, it is possible to provide a moving body including a vibrator having an excellent Q value at a low frequency.

1 is a cross-sectional view showing a vibrator according to a first embodiment of the present invention. It is a figure which shows the vibration element with which the vibrator | oscillator shown in FIG. 1 is provided, Comprising: (a) is sectional drawing, (b) is a top view. FIG. 2 is a schematic perspective view for explaining an operation of a vibration element included in the vibrator illustrated in FIG. 1. (A) is the elements on larger scale which show the vibration part and connection part of a vibration element which are shown in FIG. 2, (b) is the sectional view on the AA line in (a). It is a top view which shows the dimension of each part of the vibration element based on this invention used for simulation. (A) is a top view which shows the dimension of each part of the conventional vibration element used for simulation, (b) is a top view which shows the dimension of each part of the vibration element of the reference example used for simulation. It is a graph which shows the relationship between the resonant frequency of a vibration part, and Q value (only considering a thermoelastic loss). FIG. 3 is a diagram showing a manufacturing process of the vibrator shown in FIG. 1. FIG. 3 is a diagram showing a manufacturing process of the vibrator shown in FIG. 1. FIG. 3 is a diagram showing a manufacturing process of the vibrator shown in FIG. 1. (A) is the elements on larger scale which show the vibration part and connection part of a vibration element with which the vibrator | oscillator concerning 2nd Embodiment of this invention is equipped, (b) is the sectional view on the AA line in (a). is there. It is a figure which shows the vibration element with which the vibrator | oscillator concerning 3rd Embodiment of this invention is provided, Comprising: (a) is sectional drawing, (b) is a top view. FIG. 13 is a partially enlarged plan view showing a vibration part, a connection part, and a support part of the vibration element shown in FIG. 1 is a perspective view illustrating a configuration of a mobile (or notebook) personal computer that is a first example of an electronic apparatus according to the invention. It is a perspective view which shows the structure of the mobile telephone (PHS is also included) which is the 2nd example of the electronic device of this invention. It is a perspective view which shows the structure of the digital still camera which is the 3rd example of the electronic device of this invention. It is a perspective view which shows the structure of the motor vehicle which is an example of the mobile body of this invention.

  Hereinafter, a vibrator, an electronic device, and a moving body of the present invention will be described in detail based on each embodiment shown in the accompanying drawings.

1. Resonator <First Embodiment>
First, a first embodiment of the present invention will be described.

  FIG. 1 is a cross-sectional view showing a vibrator according to the first embodiment of the present invention. 2A and 2B are diagrams illustrating a vibration element included in the vibrator illustrated in FIG. 1. FIG. 2A is a cross-sectional view, and FIG. 2B is a plan view. FIG. 3 is a schematic perspective view for explaining the operation of the vibration element included in the vibrator shown in FIG. In the following, for convenience of explanation, the upper side in FIG. 1 is referred to as “upper” and the lower side is referred to as “lower”. Further, in FIG. 3, illustration of the connection portion is omitted for convenience of explanation.

  The vibrator 1 shown in FIG. 1 includes a substrate 2 (base body), a vibration element 5 disposed on the substrate 2, and a cavity S (cavity) housing the vibration element 5 between the substrate 2. And a laminated structure 6 that is formed. In the present embodiment, the conductor layer 3 is disposed between the substrate 2 and the laminated structure 6. Each of these parts will be described in turn below.

-Substrate 2-
The substrate 2 includes a semiconductor substrate 21, an insulating film 22 provided on one surface of the semiconductor substrate 21, and an insulating film 23 provided on the surface of the insulating film 22 opposite to the semiconductor substrate 21. Have.

  The semiconductor substrate 21 is made of a semiconductor such as silicon. The semiconductor substrate 21 is not limited to a substrate made of a single material such as a silicon substrate, and may be a substrate having a laminated structure such as an SOI substrate.

  The insulating film 22 is, for example, a silicon oxide film and has an insulating property. Further, the insulating film 23 is, for example, a silicon nitride film, and has an insulation property and resistance to an etching solution containing hydrofluoric acid. Here, since the insulating film 22 (silicon oxide film) is interposed between the semiconductor substrate 21 (silicon substrate) and the insulating film 23 (silicon nitride film), the stress generated when the insulating film 23 is formed is reduced. Propagation to the semiconductor substrate 21 can be mitigated by the insulating film 22. The insulating film 22 can also be used as an inter-element isolation film when a semiconductor circuit is formed on and above the semiconductor substrate 21. Note that the insulating films 22 and 23 are not limited to the above-described constituent materials, and any one of the insulating films 22 and 23 may be omitted as necessary.

  On the insulating film 23 of the substrate 2, the patterned conductor layer 3 is disposed. The conductor layer 3 is formed by doping (diffusing or implanting) impurities such as phosphorus and boron into single crystal silicon, polycrystalline silicon (polysilicon), or amorphous silicon, for example, and has conductivity. Although not shown, the conductor layer 3 includes a first portion that constitutes a wiring that is electrically connected to the vibration element 5 and a second portion that is electrically insulated from the first portion. It is patterned as follows.

-Vibration element 5-
As shown in FIG. 2, the vibration element 5 includes four lower electrodes 51 and 52, an upper electrode 53, and between the lower electrode 52 and the upper electrode 53 disposed on the insulating film 23 of the substrate 2. And a spacer 54 provided on the surface.

  The four lower electrodes 51 (fixed electrodes) are along the left-right direction (first direction) in FIG. 2B in plan view (hereinafter simply referred to as “plan view”) viewed from the thickness direction of the substrate 2. The two lower electrodes 51a and 51b arranged side by side and the region between the two lower electrodes 51a and 51 are straddled along the vertical direction (second direction orthogonal to the first direction) in FIG. And two lower electrodes 51c and 51d.

  The lower electrode 52 is disposed so as to be surrounded by the four lower electrodes 51 in plan view. In other words, the two lower electrodes 51 a and 51 b are arranged to face each other via the lower electrode 52 and the two lower electrodes 51 b and 51 c are arranged to face each other via the lower electrode 52 in plan view.

  The lower electrodes 51 and 52 each have a plate shape or a sheet shape along the substrate 2 and are arranged apart from each other. Although not shown, the four lower electrodes 51 are electrically connected to the wirings of the conductor layer 3 described above. Similarly, the lower electrode 52 is electrically connected to the wiring of the conductor layer 3 described above. Here, the lower electrode 51 constitutes a “substrate-side electrode”, and the two lower electrodes 51 a and 51 b are electrically connected to each other via a wiring (not shown) so that they have the same potential. It is configured. Similarly, the two lower electrodes 51c and 51d are electrically connected to each other via a wiring (not shown) and are configured to have the same potential. In addition, the planar view shape of the lower electrodes 51 and 52 is not limited to the illustrated shape. Further, the lower electrode 52 may be omitted depending on the height of the spacer 54.

  The upper electrode 53 includes a base portion 531, four vibration portions 532 extending from the base portion 531 in different directions, and a connection portion 533 connecting two adjacent vibration portions. . Here, the structure including the base portion 531 and the four vibrating portions 532 constitutes a “vibrating body 530” facing the substrate 2.

  The base 531 is fixed to the lower electrode 52 through a spacer 54. The spacer 54 has a quadrangular shape in plan view. Here, the spacer 54 and the lower electrode 52 constitute a “support portion” that connects the substrate 2 and the base portion 531. Thereby, the vibration part 532 can be supported with respect to the board | substrate 2 through the base 531 so that a vibration is possible. In addition, since the spacer 54 is between the substrate 2 and the base 531, a gap allowing vibration of the vibration part 532 can be easily formed between the vibration part 532 and the substrate 2, and stable vibration characteristics can be obtained. Can be realized. The planar view shape of the spacer 54 is not limited to a quadrangle, and may be, for example, a polygon other than a quadrangle, a circle, an ellipse, or the like.

  The four vibrating portions 532 extend in different directions from the base portion 531 so that a structure (vibrating body) composed of the base portion 531 and the four vibrating portions 532 forms a substantially cross shape.

  The four vibrating portions 532 are provided corresponding to the four lower electrodes 51 described above, and are opposed to the corresponding lower electrodes 51 with an interval therebetween. That is, the four vibrating portions 532 include two vibrating portions 532a and 532b arranged in the horizontal direction (first direction) in FIG. 2B with the base portion 531 in plan view, and the base portion 531. The two vibration parts 532c and 532d are arranged along the vertical direction (second direction orthogonal to the first direction) in FIG.

  Thus, at least a part of each vibrating portion 532 overlaps the lower electrode 51 disposed on the substrate 2 in plan view, whereby the electrostatic drive type vibrator 1 can be realized. . Here, each vibrating portion 532 has a “movable electrode” that faces the lower electrode 51.

  In the present embodiment, each vibration part 532 has a rectangular shape in plan view. In addition, the planar view shape of each vibration part 532 is not limited to this, For example, the shape where a width | variety becomes small as it leaves | separates from the base 531 may be sufficient.

  The four connecting portions 533 are provided corresponding to two adjacent vibrating portions 532, and connect the corresponding two vibrating portions 532, respectively. That is, the four connection portions 533 connect the connection portions 533a connecting the vibration portions 532a and 532c, the connection portions 533b connecting the vibration portions 532b and 532d, and the vibration portions 532b and 532c. The connecting portion 533c is connected to the vibrating portions 532a and 532d. The configuration of each connection portion 533 will be described in detail later.

  The lower electrodes 51 and 52, the upper electrode 53, and the spacer 54 are configured by doping (diffusing or implanting) impurities such as phosphorus and boron into single crystal silicon, polycrystalline silicon (polysilicon), or amorphous silicon, respectively. It has electrical conductivity. The spacer 54 may be formed integrally with the lower electrode 52 or the upper electrode 53.

  Further, the film thicknesses of the lower electrodes 51 and 52 are not particularly limited, but are preferably 0.1 μm or more and 1.0 μm or less, for example. The film thickness of the upper electrode 53 is not particularly limited, but is preferably 0.1 μm or more and 10.0 μm or less, for example. The thickness of the spacer 54 is not particularly limited as long as the vibration of the vibrating portion 532 can be allowed, but is preferably 0.03 μm or more and 2.0 μm or less, for example.

-Laminated structure 6
The laminated structure 6 is formed so as to define a cavity S that houses the vibration element 5. The laminated structure 6 includes an interlayer insulating film 61 formed on the substrate 2 so as to surround the vibration element 5 in a plan view, a wiring layer 62 formed on the interlayer insulating film 61, a wiring layer 62, and an interlayer insulating film. An interlayer insulating film 63 formed on the film 61; a wiring layer 64 having a covering layer 641 formed on the interlayer insulating film 63 and having a plurality of pores 642 (openings); the wiring layer 64 and the interlayer A surface protective film 65 formed on the insulating film 63 and a sealing layer 66 provided on the covering layer 641 are provided.

  Each of the interlayer insulating films 61 and 63 is, for example, a silicon oxide film. The wiring layers 62 and 64 and the sealing layer 66 are each made of a metal such as aluminum. The surface protective film 65 is a silicon nitride film, for example.

  In addition to the above-described configuration, a semiconductor circuit may be built on and above the semiconductor substrate 21. This semiconductor circuit includes an active element such as a MOS transistor, a capacitor, an inductor, a resistor, a diode, a wiring (a wiring connected to the lower electrode 51 or a wiring connected to the upper electrode 53, as necessary) Circuit elements including the wiring layers 62 and 64). Although not shown, between the wiring layer 62 and the insulating film 23, the wiring electrically connected to the vibration element 5 described above is disposed across the inside and outside of the cavity S, and the wiring layer 62 is The wiring is formed so as to be separated from the wiring.

The cavity S defined by the substrate 2 and the laminated structure 6 functions as a housing portion that houses the vibration element 5. The cavity S is a sealed space. In this embodiment, the cavity S is in a vacuum state (300 Pa or less). Thereby, the vibration characteristic of the vibration element 5 can be made excellent. However, the cavity S may not be in a vacuum state, may be atmospheric pressure, may be in a reduced pressure state where the atmospheric pressure is lower than atmospheric pressure, or is a pressurized state where the atmospheric pressure is higher than atmospheric pressure. It may be. The cavity S may be filled with an inert gas such as nitrogen gas or a rare gas.
The configuration of the vibrator 1 has been briefly described above.

  In the vibrator 1 configured as described above, a first voltage (alternating voltage) that periodically changes is applied between the lower electrodes 51a and 51b and the upper electrode 53, and the lower electrodes 51c and 51d and the upper electrode are applied. A second voltage similar to the first voltage is applied except that the phase is shifted by 180 ° between the first voltage and the third voltage.

  Then, the vibration parts 532a and 532b are alternately displaced in a direction approaching and separating from the lower electrodes 51a and 51b to bend and vibrate, and are in opposite phases to the vibration parts 532a and 532b. 532d is alternately displaced in the direction approaching and separating from the lower electrodes 51c and 51d, and bends and vibrates. That is, as shown in FIG. 3, the vibration parts 532a, 532b, 532c, and 532d are displaced in the direction indicated by the solid line arrows in FIG. 3, and the vibration parts 532a, 532b, 532c, and 532d are the broken line arrows in FIG. The state of displacement in the direction shown is repeated alternately.

  In this way, by vibrating the vibrating portions 532a and 532b and the vibrating portions 532c and 532d in opposite phases, vibration transmitted from the vibrating portions 532a and 532b to the base portion 531 and vibration transmitted from the vibrating portions 532c and 532d to the base portion 531 are generated. Can be offset each other. As a result, these vibrations leak to the outside (substrate 2) via the base 531 and the spacer 54, so-called vibration leakage can be reduced, and the vibration efficiency of the vibrator 1 can be increased. As described above, the vibrator 1 has a plurality of the vibration parts 532, thereby reducing vibration leakage from the vibration parts 532 to the outside, and as a result, the Q value can be improved.

  Such a vibrator 1 can be used, for example, as an oscillator that extracts a signal of a predetermined frequency by combining with an oscillation circuit (drive circuit). Such an oscillation circuit can be provided on the substrate 2 as a semiconductor circuit. The vibrator 1 can also be applied to various sensors such as a gyro sensor, a pressure sensor, an acceleration sensor, and a tilt sensor.

(Connection part)
Hereinafter, the connection portion 533 will be described in detail.

  4A is a partially enlarged plan view showing a vibrating portion and a connecting portion of the vibrating element shown in FIG. 2, and FIG. 4B is a cross-sectional view taken along line AA in FIG. 4A. FIG. 5 is a plan view showing dimensions of each part of the vibration element according to the present invention used in the simulation. FIG. 6A is a plan view showing dimensions of each part of the conventional vibration element used in the simulation, and FIG. 6B is a plan view showing dimensions of each part of the vibration element of the reference example used in the simulation. . FIG. 7 is a graph showing the relationship between the resonance frequency of the vibrating portion and the Q value (considering only thermoelastic loss).

  As described above, the upper electrode 53 has the four connection portions 533 that respectively connect the two vibration portions 532 adjacent to each other. Thereby, the thermoelastic loss which arises between the two vibration parts 532 adjacent to each other can be reduced. Therefore, the Q value can be improved.

  In particular, each connection portion 533 includes a beam portion 5331 and a through hole 5332. As described above, the connection portion 533 having the through-hole 5332 can prevent the rigidity of the connection portion 533 from becoming too high, and can reduce an excessive increase in the resonance frequency of the vibration portion 532. Here, since the through-hole 5332 penetrates the upper electrode 53, the resonance frequency of the vibration part 532 can be effectively reduced. Further, as will be described later, when the gap between the vibrating portion 532 and the substrate 2 that supports it is formed by release etching, an etching solution can be supplied through the through-hole 5332, thereby shortening the time required for release etching. be able to.

  Further, the beam portion 5331 connects the two vibrating portions 532 adjacent to each other. The through hole 5332 is disposed between the beam portion 5331 and the two vibration portions 532. In other words, the through-hole 5332 is disposed at a portion of the connection portion 533 on the base portion 531 side. Thereby, the balance between the reduction of the thermoelastic loss and the reduction of the resonance frequency of the vibration part 532 can be made excellent.

  Each vibration element formed with dimensions as shown in FIGS. 5 and 6A and 6B was analyzed by the finite element method. Specifically, the vibration element shown in FIG. 5 is the same as the vibration element 5 shown in FIG. 2 in plan view, the width of each vibration part 532 is 9.0 μm, the length of each vibration part 532 is 6.3 μm, The width of the portion where the portion 5331 and the vibrating portion 532 are connected is 0.5 μm, the width of the through hole 5332 in the direction in which the vibrating portion 532 extends is 0.5 μm, and the length of each side of the spacer 54 is 2 μm. Moreover, the thickness of each part is 1.3 μm. Further, the vibration element shown in FIG. 6A is the same as the vibration element shown in FIG. 5 except that the beam portion 5331 is omitted, and the vibration element shown in FIG. Other than the above, the vibration element is the same as that shown in FIG.

  As shown in FIG. 7, the vibration element according to the present invention shown in FIG. 5 (with a connection portion (with a hole)) has a markedly higher Q value than the vibration element (without a connection portion) shown in FIG. Has improved. Further, the vibration element shown in FIG. 5 has a higher resonance frequency than the vibration element shown in FIG. 6 (a), but compared with the vibration element shown in FIG. 6 (b) (with a connecting portion (no hole)). The resonance frequency can be lowered. As described above, the vibrator 1 can improve the Q value while lowering the resonance frequency of the vibration unit 532. Note that such an analysis result is obtained even if the dimensions of each part of the vibration element are changed to some extent.

  Further, when the width of the portion where the beam portion 5331 and the vibration portion 532 are connected is a and the width of the through hole 5332 in the extending direction of the vibration portion 532 is b, 0.6 ≦ b / a ≦ 1 0.6, preferably 0.8 ≦ b / a ≦ 1.4, and more preferably 0.8 ≦ b / a ≦ 1.2. Thereby, the balance between the reduction of the thermoelastic loss and the reduction of the resonance frequency of the vibration part 532 can be made excellent. On the other hand, if b / a is too small or too large, depending on the size of a, the thickness of the beam portion 5331, or the like, the Q value cannot be sufficiently improved, or the resonance frequency of the vibration portion 532 is increased. It may become too high.

  Moreover, when the length of the vibration part 532 is set to c, it is preferable to satisfy | fill the relationship of 4 <= c / (a + b) <= 10, and it is more preferable to satisfy | fill the relationship of 4 <= c / (a + b) <= 8. Thereby, the balance between the reduction of the thermoelastic loss and the reduction of the resonance frequency of the vibration part 532 can be made excellent while making the vibration characteristics of the vibration part 532 excellent. On the other hand, if c / (a + b) is too small, the effect of sufficiently reducing the thermoelastic loss tends to be small depending on the size of a, the thickness of the beam portion 5331, and the like. On the other hand, if c / (a + b) is too large, depending on the size of a, the thickness of the beam portion 5331, etc., it becomes difficult to reduce the resonance frequency of the vibration portion 532, or unnecessary vibration of the vibration portion 532 occurs. There is a case to do.

  The width w along the direction perpendicular to the direction in which the beam portion 5331 extends is about 0.7 with respect to the width a described above.

  In the present embodiment, the thickness of the beam portion 5331 is equal to the thickness of the vibrating portion 532. Thereby, manufacture of vibrator 1 can be made easy. Note that the thickness of the beam portion 5331 may be different from the thickness of the vibrating portion 532.

  Further, in the present embodiment, the beam portion 5331 extends linearly with a constant width. Thereby, it is possible to connect two adjacent vibrating portions 532 with a relatively simple configuration. Note that the shape of the beam portion 5331 is not limited to that described above, and for example, the beam portion 5331 may have a portion with a different width, or may have a branched portion, a curved or bent portion. Further, the planar view shape of the through hole 5332 is not limited to the illustrated shape, and can be appropriately set according to the planar view shape of the beam portion 5331, for example.

(Manufacturing method of vibrator)
Next, a method for manufacturing the vibrator 1 will be briefly described.

  8 to 10 are diagrams showing manufacturing steps of the vibrator shown in FIG. Hereinafter, description will be made based on these drawings.

[Vibration element forming process]
First, as shown in FIG. 8A, a semiconductor substrate 21 (silicon substrate) is prepared.

  When a semiconductor circuit is formed on or above the semiconductor substrate 21, the source and drain of the MOS transistor of the semiconductor circuit are ionized on the portion of the upper surface of the semiconductor substrate 21 where the insulating film 22 and the insulating film 23 are not formed. Doped to form.

  Next, as shown in FIG. 8B, an insulating film 22 (silicon oxide film) is formed on the upper surface of the semiconductor substrate 21.

  A method for forming the insulating film 22 (silicon oxide film) is not particularly limited, and for example, a thermal oxidation method (including a LOCOS method and an STI method), a sputtering method, a CVD method, and the like can be used. The insulating film 22 may be patterned as necessary. For example, when a semiconductor circuit is formed on or over the upper surface of the semiconductor substrate 21, a part of the upper surface of the semiconductor substrate 21 is exposed. The insulating film 22 is patterned.

  Thereafter, as shown in FIG. 8C, an insulating film 23 (silicon nitride film) is formed on the insulating film 22.

  A method for forming the insulating film 23 (silicon nitride film) is not particularly limited, and for example, a sputtering method, a CVD method, or the like can be used. The insulating film 23 may be patterned as necessary. For example, when a semiconductor circuit is formed on or above the semiconductor substrate 21, a part of the upper surface of the semiconductor substrate 21 is exposed. The insulating film 23 is patterned.

  Next, as shown in FIG. 8D, a conductor film 71 for forming the conductor layer 3 and the lower electrodes 51 and 52 is formed on the insulating film 23.

  Specifically, for example, after a silicon film made of polycrystalline silicon or amorphous silicon is formed on the insulating film 23 by sputtering, CVD, or the like, the silicon film is doped with impurities such as phosphorus. A conductor film 71 is formed. Depending on the configuration of the insulating film 23, the conductor film 71 may be formed by doping an epitaxially grown silicon film with an impurity such as phosphorus.

  Next, the conductor film 71 is patterned to form the conductor layer 3 and the lower electrodes 51 and 52 as shown in FIG.

  Specifically, for example, a photoresist is applied onto the conductor film 71 and patterned into the shape of the conductor layer 3 and the lower electrodes 51 and 52 (planar shape) to form a photoresist film. Then, the conductor film 71 is etched using the photoresist film as a mask, and then the photoresist film is removed. Thereby, the conductor layer 3 and the lower electrodes 51 and 52 are formed.

  When a semiconductor circuit is formed on or above the upper surface of the semiconductor substrate 21, for example, the conductor film 71 is patterned simultaneously with the patterning of the lower electrodes 51, 52, etc., and the gate electrode of the MOS transistor of the semiconductor circuit Form.

Next, as shown in FIG. 9F, a spacer 54 is formed on the lower electrode 52.
The formation of the spacer 54 can be performed in the same manner as the formation of the lower electrodes 51 and 52 and the conductor layer 3 described above.

  Next, as shown in FIG. 9G, a sacrificial layer 72 is formed so as to cover the lower electrodes 51 and 52 and the conductor layer 3 and to expose the spacer 54.

  In this embodiment, the sacrificial layer 72 is a silicon oxide film, and a part thereof is removed and the remaining part becomes a part of the interlayer insulating film 61 in a process described later.

  The method for forming the sacrificial layer 72 is not particularly limited, and for example, a sputtering method or a CVD method can be used. Further, when the sacrificial layer 72 is formed, planarization by etch back or chemical mechanical polishing (CMP) is performed as necessary. The sacrificial layer 72 may be formed only on the lower electrodes 51 and 52 and the substrate 2 in the vicinity thereof, and may not be formed on the conductor layer 3. In this case, almost all of the sacrificial layer 72 is removed in a process described later.

Next, as shown in FIG. 9H, the upper electrode 53 is formed.
Specifically, for example, after a polycrystalline silicon film or an amorphous silicon film is deposited on the sacrificial layer 72 so as to be in contact with the spacer 54 by a sputtering method, a CVD method or the like, a silicon film is formed. A conductor film is formed by doping impurities such as, and then the conductor film is patterned. Depending on the configuration of the sacrificial layer 72, the conductor film may be formed by doping an epitaxially grown silicon film with an impurity such as phosphorus. Further, the silicon film may be planarized by etch back or CMP (chemical mechanical plishing).

  In the patterning of the conductor film, for example, a photoresist is applied on the conductor film and patterned into the shape of the upper electrode 53 (a shape in plan view) to form a photoresist film. Then, the conductor film is etched using the photoresist film as a mask, and then the photoresist film is removed. Thereby, the upper electrode 53 is formed.

  As described above, the vibration element 5 including the lower electrodes 51 and 52, the upper electrode 53, and the spacer 54 is formed.

[Cavity formation process]
As shown in FIG. 9I, a sacrificial layer 73 is formed on the sacrificial layer 72.

  In this embodiment, the sacrificial layer 73 is a silicon oxide film, and a part thereof is removed and the remaining part becomes a part of the interlayer insulating film 61 in a process described later.

  The sacrificial layer 73 can be formed in the same manner as the sacrificial layer 72 described above.

Next, as shown in FIG. 9J, a wiring layer 62 is formed.
Specifically, for example, the stacked body including the sacrificial layers 72 and 73 is patterned by etching to form a through hole having a shape corresponding to the wiring layer 62, and then the stacked body is filled with the through hole. A wiring layer 62 is formed by forming a film made of aluminum by sputtering, CVD, or the like and patterning the film by etching (removing unnecessary portions).

  Next, as shown in FIG. 10K, a sacrificial layer 74, a wiring layer 64, and a surface protective film 65 are formed in this order on the sacrificial layer 73 and the wiring layer 62.

  Specifically, the sacrificial layer 74 is formed on the sacrificial layer 73 and the wiring layer 62 in the same manner as the sacrificial layers 72 and 73 described above, and then the wiring layer 62 is formed in the same manner as the wiring layer 62 is formed. 64 is formed. After the wiring layer 64 is formed, a surface protective film 65 made of a silicon oxide film, a silicon nitride film, a polyimide film, an epoxy resin, or the like is formed by a sputtering method, a CVD method, or the like.

  Note that such a laminated structure of the interlayer insulating film and the wiring layer is formed by a normal CMOS process, and the number of laminated layers is appropriately set as necessary. In other words, more wiring layers may be stacked via an interlayer insulating film as necessary. When a semiconductor circuit is formed on or above the upper surface of the semiconductor substrate 21, for example, a wiring layer that is electrically connected to the gate electrode of the MOS transistor of the semiconductor circuit at the same time as the formation of the wiring layers 62 and 64. Form.

  Next, as shown in FIG. 10 (l), the sacrificial layers 72, 73, 74 are partially removed to form the cavity S and the interlayer insulating films 61, 63.

  Specifically, by etching through the plurality of pores 642 formed in the coating layer 641, the periphery of the vibration element 5, between the lower electrode 51 and the vibration part 532, and between the substrate 2 and the base part 531. Some sacrificial layers 72, 73, 74 are removed. As a result, a cavity S in which the vibration element 5 is accommodated is formed, and a gap is formed between the lower electrode 51 and the vibration part 532 and between the substrate 2 and the base part 531. It will be in the state which can drive.

  Here, the removal (release process) of the sacrificial layers 72, 73, and 74 is performed, for example, by wet etching that supplies hydrofluoric acid, buffered hydrofluoric acid, or the like as an etchant from the plurality of pores 642, or from the plurality of pores 642. It can be performed by dry etching in which hydrofluoric acid gas or the like is supplied as an etching gas. At this time, the insulating film 23 and the wiring layers 62 and 64 have resistance to etching performed in the release process, and function as a so-called etching stop layer. Moreover, since each part which comprises the vibration element 5 is also comprised by the silicon | silicone, it has the tolerance with respect to the etching used for a release process. Note that a protective film may be formed of a photoresist or the like on the outer surface of the structure including a portion to be etched before the etching, if necessary.

Next, as illustrated in FIG. 10M, the sealing layer 66 is formed on the covering layer 641.
Specifically, for example, a sealing layer 66 composed of a silicon oxide film, a silicon nitride film, a metal film such as Al, Cu, W, Ti, or TiN is formed by a sputtering method, a CVD method, or the like. The hole 642 is sealed.
The vibrator 1 can be manufactured through the steps as described above.

Second Embodiment
Next, a second embodiment of the present invention will be described.

  FIG. 11A is a partially enlarged plan view showing a vibrating portion and a connecting portion of a vibrating element included in the vibrator according to the second embodiment of the present invention, and FIG. 11B is A in FIG. FIG.

Hereinafter, although 2nd Embodiment of this invention is described, it demonstrates centering around difference with embodiment mentioned above, The description of the same matter is abbreviate | omitted.
The second embodiment is the same as the first embodiment described above except that the configuration of the connecting portion is different.

  As shown in FIG. 11A, the vibration element 5A included in the vibrator 1A of the present embodiment includes a connection portion 533A that connects between two vibration portions 532 adjacent to each other. As shown in FIGS. 11A and 11B, the connection portion 533A includes a beam portion 5331 and a recess portion 5333.

  The vibrator 1A using such a connection portion 533A was analyzed by the finite element method as in the first embodiment, and compared with the vibration element (without the connection portion) shown in FIG. It has been confirmed that the Q value is remarkably improved, and the resonance frequency is lower than that of the resonator element (with the connecting portion (without the hole)) shown in FIG.

  Here, when the width of the portion where the beam portion 5331 and the vibrating portion 532 are connected is a and the width of the concave portion 5333 in the extending direction of the vibrating portion 532 is b, 0.6 ≦ b / a ≦ 1. 0.6, preferably 0.8 ≦ b / a ≦ 1.4, and more preferably 0.8 ≦ b / a ≦ 1.2. Thereby, the balance between the reduction of the thermoelastic loss and the reduction of the resonance frequency of the vibration part 532 can be made excellent. On the other hand, if b / a is too small or too large, depending on the size of a, the thickness of the beam portion 5331, or the like, the Q value cannot be sufficiently improved, or the resonance frequency of the vibration portion 532 is increased. It may become too high.

  Further, d / t is preferably 0.5 or more, and more preferably 0.8 or more, where d is the depth of the concave portion 5333 and t is the thickness of the beam portion 5331. Thereby, the resonant frequency of the vibration part 532 can be reduced efficiently.

In this embodiment, the concave portion 5333 is formed on one surface of the connecting portion 533A, but the concave portion 5333 may be formed on both surfaces of the connecting portion 533A. In this case, the depth d is the sum of the depths of the two recesses 5333.
The Q value can also be improved by the second embodiment as described above.

<Third Embodiment>
Next, a third embodiment of the present invention will be described.

  12A and 12B are diagrams illustrating a vibration element included in a vibrator according to the third embodiment of the present invention, in which FIG. 12A is a cross-sectional view, and FIG. 12B is a plan view. FIG. 13 is a partially enlarged plan view showing a vibration part, a connection part, and a support part of the vibration element shown in FIG.

Hereinafter, the third embodiment of the present invention will be described. The description will focus on differences from the above-described embodiment, and description of similar matters will be omitted.
3rd Embodiment is the same as that of 1st Embodiment mentioned above except the structure of a support part differing.

  As shown in FIG. 12, the vibration element 5 </ b> B included in the vibrator 1 </ b> B of the present embodiment includes four lower electrodes 52 </ b> B, four spacers 54 </ b> B, and four support portions 534 provided corresponding to the connection portions 533.

  The four lower electrodes 52B are, in plan view, a lower electrode 52a disposed corresponding to the lower electrodes 51a and 51c, a lower electrode 52b disposed corresponding to the lower electrodes 51b and 51d, and a lower electrode 51b. , 51c, and a lower electrode 52d disposed between the lower electrodes 51a and 51d.

  The four spacers 54B are provided corresponding to the four lower electrodes 52B described above. That is, the four spacers 54B include a spacer 54a corresponding to the lower electrode 52a, a spacer 54b corresponding to the lower electrode 52b, a spacer 54c corresponding to the lower electrode 52c, and a spacer 54d corresponding to the lower electrode 52d. Has been.

  The four support portions 534 are provided corresponding to the four lower electrodes 52B and the spacers 54B described above. That is, the four support portions 534 include a support portion 534a corresponding to the lower electrode 52a and the spacer 54a, a support portion 534b corresponding to the lower electrode 52b and the spacer 54b, and a support portion 534c corresponding to the lower electrode 52c and the spacer 54c. , And a support portion 534d corresponding to the lower electrode 52d and the spacer 54d.

  As shown in FIG. 13, each support portion 534 includes a fixing portion 5341 fixed to the lower electrode 52B via a spacer 54B, and a beam portion 5342 connecting the fixing portion 5341 and the connecting portion 533. Have. Note that the shapes of the fixed portion 5341 and the beam portion 5342 are not limited to those illustrated. For example, the planar view shape of the fixing portion 5341 is not limited to a quadrangle, and may be, for example, a circle, an ellipse, a polygon other than a quadrangle, or the like. Moreover, the planar view shape of the beam part 5342 is not limited to what is linearly extended by fixed width, For example, you may have a part from which width differs, a branched part, a bent or curved part Etc. may be included.

  By using such a plurality of support portions 534 to support the structure including the base portion 531 and the vibration portion 532 (“vibration body 530”), the vibration body 530 can be stably supported. As a result, the vibration characteristics of the vibrator 1B can be made excellent.

  In addition, since each support portion 534 is connected to the connection portion 533 (more specifically, the beam portion 5331), the vibration portion 532 (vibration body 530) can be supported at a portion that becomes a vibration node, As a result, a decrease in Q value due to vibration leakage can be reduced. In particular, since the beam portion 5331 of the connection portion 533 has a spring property, vibration leakage can be effectively reduced.

Here, the width w1 of the beam portion 5342 of the support portion 534 is smaller than the length L1 of the side surface on the support portion 534 side (the side opposite to the base portion 531) of the beam portion 5331 of the connection portion 533. Thereby, the elasticity of the beam part 5331 can be exhibited suitably.
The Q value can also be improved by the third embodiment as described above.

2. Electronic Device Next, an electronic device (electronic device of the present invention) to which the vibrator of the present invention is applied will be described in detail with reference to FIGS.

  FIG. 14 is a perspective view showing the configuration of a mobile (or notebook) personal computer which is a first example of the electronic apparatus of the present invention. In this figure, a personal computer 1100 includes a main body portion 1104 provided with a keyboard 1102 and a display unit 1106 provided with a display portion 2000. The display unit 1106 rotates with respect to the main body portion 1104 via a hinge structure portion. It is supported movably. Such a personal computer 1100 has a built-in vibrator 1 (oscillator).

  FIG. 15 is a perspective view showing a configuration of a mobile phone (including PHS) as a second example of the electronic apparatus of the invention. In this figure, a cellular phone 1200 includes a plurality of operation buttons 1202, a earpiece 1204, and a mouthpiece 1206, and a display unit 2000 is disposed between the operation buttons 1202 and the earpiece 1204. Such a cellular phone 1200 has a built-in vibrator 1 (oscillator).

  FIG. 16 is a perspective view showing a configuration of a digital still camera which is a third example of the electronic apparatus of the invention. In this figure, connection with an external device is also simply shown. Here, an ordinary camera sensitizes a silver halide photographic film with a light image of a subject, whereas a digital still camera 1300 photoelectrically converts a light image of a subject with an imaging device such as a CCD (Charge Coupled Device). An imaging signal (image signal) is generated.

  A display unit 2000 is provided on the back of a case (body) 1302 in the digital still camera 1300, and is configured to display based on an imaging signal from the CCD. The display unit 2000 displays a subject as an electronic image. Functions as a viewfinder. A light receiving unit 1304 including an optical lens (imaging optical system), a CCD, and the like is provided on the front side (the back side in the drawing) of the case 1302.

  When the photographer confirms the subject image displayed on the display unit 2000 and presses the shutter button 1306, the CCD image pickup signal at that time is transferred and stored in the memory 1308. In the digital still camera 1300, a video signal output terminal 1312 and an input / output terminal 1314 for data communication are provided on the side surface of the case 1302. As shown in the figure, a television monitor 1430 is connected to the video signal output terminal 1312 and a personal computer 1440 is connected to the input / output terminal 1314 for data communication as necessary. Further, the imaging signal stored in the memory 1308 is output to the television monitor 1430 or the personal computer 1440 by a predetermined operation. Such a digital still camera 1300 has a built-in vibrator 1 (oscillator).

  Note that the electronic device including the vibrator of the present invention includes, for example, a smartphone, a tablet terminal, a watch, in addition to the personal computer (mobile personal computer) in FIG. 14, the mobile phone in FIG. 15, and the digital still camera in FIG. , Inkjet dispenser (for example, inkjet printer), laptop personal computer, TV, video camera, video tape recorder, car navigation device, pager, electronic notebook (including communication function), electronic dictionary, calculator, electronic game machine , Word processor, workstation, video phone, security TV monitor, electronic binoculars, POS terminal, medical equipment (eg electronic thermometer, blood pressure monitor, blood glucose meter, electrocardiogram measuring device, ultrasonic diagnostic device, electronic endoscope), fish school Machine, various measurements Equipment, instruments (e.g., gages for vehicles, aircraft, and ships), can be applied to a flight simulator or the like.

3. FIG. 17 is a perspective view showing a configuration of an automobile which is an example of the moving body of the present invention.

  In this figure, an automobile 1500 (moving body) has a vehicle body 1501 and four wheels 1502, and is configured to rotate the wheels 1502 by a power source (engine) (not shown) provided in the vehicle body 1501. ing. Such an automobile 1500 has a built-in vibrator 1 (oscillator).

  In addition, the mobile body of this invention is not limited to a motor vehicle, For example, it can apply to various mobile bodies, such as an aircraft, a ship, a motorcycle.

  As mentioned above, although the vibrator | oscillator, electronic device, and moving body of this invention were demonstrated based on each embodiment of illustration, this invention is not limited to these, The structure of each part is arbitrary which has the same function. It can be replaced with that of the configuration. Moreover, other arbitrary components may be added.

1 ... vibrator 1A ... vibrator 1B ... vibrator 2 ... substrate 3 ... conductor layer 5 ... vibration element 5A ... vibration element 5B ... vibration element 6 ... laminated structure 21 ... semiconductor substrate 22 ... Insulating film 23 ... Insulating film 51 ... Lower electrode 51a ... Lower electrode 51b ... Lower electrode 51c ... Lower electrode 51d ... Lower electrode 52 ... Lower electrode 52B ... Lower electrode 52a ... Lower electrode 52b ... Lower electrode 52c ... Lower electrode 52d ... Lower electrode 53 ... Upper electrode 54 ... Spacer 54B ... Spacer 54a ... Spacer 54b ... Spacer 54c ... Spacer 54d ... Spacer 61 ... Interlayer insulating film 62 ... wiring layer 63 ... interlayer insulating film 64 ... wiring layer 65 ... surface protective film 66 ... sealing layer 71 ... conductor film 72 ... sacrificial layer 73 ... sacrificial layer 74 ... sacrificial layer 530 ... …… Vibrating body 31 ... Base 532 ... Vibration part 532a ... Vibration part 532b ... Vibration part 532c ... Vibration part 532d ... Vibration part 533 ... Connection part 533A ... Connection part 533a ... Connection part 533b ... Connection part 533c Connection portion 533d Connection portion 534 Support portion 534a Support portion 534b Support portion 534c Support portion 534d Support portion 641 Cover layer 642 Pore 1100 Personal computer 1102 Keyboard 1104 Main unit 1106 Display unit 1200 Mobile phone 1202 Operation buttons 1204 Earpiece 1206 Transmission mouth 1300 Digital still camera 1302 Case 1304 Light receiving unit 1306 Shutter button 1308 Memory 1312 Video signal output terminal 1314 Input / output terminal 1430 TV monitor 1440 Personal computer 1500 Automobile 1501 Car body 1502 Wheel 2000 Display section 5331 Beam section 5332 Through hole 5333 Recessed section 5341 Fixed section 5342 ... Beam S ... Hollow

Claims (9)

The base,
A plurality of vibrating portions extending in different directions from the base portion;
Connecting the two vibrating parts adjacent to each other, and a connecting part having a through hole or a recess,
A vibrator comprising: A substrate,
A support part connecting the substrate and the base part;
The vibrator according to claim 1.   The vibrator according to claim 1, wherein at least a part of the support portion is between the substrate and the base portion.   The vibrator according to claim 1, wherein the support portion is connected to the connection portion. The connecting portion has a beam portion connecting the two vibrating portions,
5. The vibrator according to claim 1, wherein the through hole or the concave portion is disposed between the beam portion and the two vibrating portions. When the width of the part where the beam part and the vibration part are connected is a, and the width along the extending direction of the vibration part of the through hole or the recess is b,
The vibrator according to claim 5, satisfying a relationship of 0.6 ≦ b / a ≦ 1.6. Comprising a substrate side electrode disposed on the substrate;
The vibrator according to claim 1, wherein the vibration unit includes a movable electrode facing the substrate-side electrode.   An electronic apparatus comprising the vibrator according to claim 1.   A moving body comprising the vibrator according to claim 1.

Images