JP2014078905A - Vibrator, electronic apparatus, and manufacturing method of vibrator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vibrator which is stably manufactured without causing sticking in a movable electrode during a manufacturing process.SOLUTION: An MEMS vibrator 100 includes: a wafer substrate 1; a fixed lower electrode 20 (a first electrode) provided on a main surface of the wafer substrate 1; a support member 40 where one end part is fixed to the wafer substrate 1; and a movable upper electrode 30 (a second electrode) which is joined to the other end part of the support member 40 and has a region overlapping with the fixed lower electrode 20 through a clearance. The support member 40 has a reinforcement region 40s where the support member 40 is thicker than the movable upper electrode 30 when viewed in a thickness direction of the wafer substrate 1.

Description

  The present invention relates to a vibrator, an electronic device, and a method for manufacturing the vibrator.

  In general, an electromechanical structure (eg, vibrator, filter, sensor, motor, etc.) having a mechanically movable structure called a MEMS (Micro Electro Mechanical System) device formed by using microfabrication technology It has been known. Among these, the MEMS vibrator is easier to manufacture by incorporating a semiconductor circuit than a vibrator / resonator using a crystal or dielectric that has been mainly used so far. Since it is advantageous for high functionality, its use is becoming active.

  As a typical example of a conventional MEMS vibrator, a comb vibrator that vibrates in a direction parallel to the substrate surface and a beam vibrator that vibrates in the thickness direction of the substrate are known. A beam type vibrator is a vibrator composed of a lower electrode (fixed electrode) formed on a substrate and an upper electrode (movable electrode) disposed above the lower electrode with a gap therebetween. Depending on the method, a cantilever beam type, a clamped-clamped beam type, a free-free beam type on both ends, and the like are known.

  The both-end free-beam type MEMS vibrator is supported by the support member at the vibration node of the vibrating upper electrode, and therefore has little vibration leakage to the substrate and high vibration efficiency. Patent Document 1 proposes a technique for improving the vibration characteristics by setting the length of the support member to an appropriate length with respect to the vibration frequency.

US Pat. No. 6,930,569B2

  However, the above-described conventional technology including the MEMS vibrator described in Patent Document 1 has a problem that it cannot sufficiently meet needs such as downsizing, thinning, power saving, and high frequency. Specifically, in order to cope with downsizing, thinning, power saving, high frequency, etc., both ends of the free electrode type MEMS vibrator is used to reduce the stiffness of the upper electrode and the support part. It was effective to reduce the gap between the electrodes, but as a result, there was a problem that the upper electrode was stuck in the manufacturing process and a sufficient manufacturing yield could not be obtained. Sticking is a phenomenon in which a fine structure adheres to a substrate or another structure when a sacrificial layer is removed by etching in order to form a MEMS structure. That is, in the prior art, the problem that the upper electrode sticks to the lower electrode in the manufacturing process has become apparent along with the response to the above needs.

  SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following application examples or forms.

  Application Example 1 A vibrator according to this application example includes a substrate, a first electrode provided on a main surface of the substrate, a support member having one end fixed to the substrate, and the support. A second electrode having a region joined to the other end of the member and overlapping the first electrode via a gap, wherein the support member has a thickness direction of the substrate of the support member The second electrode has a reinforcing region that is thicker than the thickness of the second electrode in the thickness direction of the substrate.

  According to this application example, in the support member that supports the second electrode having a region overlapping the first electrode via a gap, the thickness of the support member is the thickness of the second electrode in the thickness direction of the substrate. It has a thicker reinforcement area. This reinforcing region increases the rigidity of the support member in the thickness direction of the substrate. As a result, even when an external force is applied in a direction in which the second electrode is brought closer to the first electrode, the second electrode is less likely to approach the first electrode. Therefore, for example, when the sacrificial layer is removed by etching to form the second electrode and the first electrode, the surface tension of the etching solution or the cleaning solution acts between the second electrode and the first electrode. Even in this case, the sticking phenomenon that the second electrode adheres to the first electrode is less likely to occur. As a result, yield reduction due to sticking can be suppressed.

  Application Example 2 In the vibrator according to the application example, the second electrode is a vibration plate that bends and vibrates in the thickness direction of the substrate, and the bending vibration node portion of the second electrode is the vibration plate. It is joined to the other end of the support member.

  According to this application example, the second electrode is a vibration plate that bends and vibrates in the thickness direction of the substrate, and the node portion of the second electrode that is bent and vibrated is joined to the other end of the support member. Yes. Further, the rigidity of the support member is enhanced in the thickness direction of the substrate by the reinforcing region. Therefore, even if the rigidity of the support member is increased and the stiffness thereof is increased, the support member supports the vibration node of the second electrode, so that the vibration is not greatly hindered. That is, the sticking phenomenon can be suppressed by supporting the second electrode more effectively without adversely affecting the vibration characteristics.

  Application Example 3 In the vibrator according to the application example described above, both ends of the bending vibration node of the second electrode are supported by a pair of the support members, and the second electrode includes a plurality of the pair of pairs. It is supported by the support member.

  According to this application example, both ends of the vibration node portion of the second electrode are supported by the pair of support members, and the second electrode is supported by the pair of support members at a plurality of locations. . Since the second electrode is supported by a plurality of support members, the sticking phenomenon is more effectively suppressed. In addition, since the second electrode supports the vibration node portion, the vibration characteristics are not deteriorated.

  Application Example 4 In the vibrator according to the application example described above, in the reinforcing region, the thickness of the support member in the thickness direction of the substrate is greater than the thickness of the second electrode in the thickness direction of the substrate. It is preferable that the region is thick in the direction away from the main surface.

  As in this application example, the reinforcing region is configured by a thick region in a direction away from the main surface of the substrate with respect to the support member, so that the size (distance) between the second electrode and the first electrode is increased. The rigidity of the support member can be increased without changing (). That is, the sticking phenomenon can be suppressed without deteriorating the characteristics as a vibrator.

  Application Example 5 In the vibrator according to the application example described above, the thickness of the reinforcing region in the thickness direction of the substrate increases as the distance from the other end of the support member increases.

  According to this application example, the thickness of the reinforcing region in the thickness direction of the substrate increases as the distance from the other end of the support member increases. By comprising in this way, since it suppresses that the stress from a support member concentrates on the joint part of a support member and a 2nd electrode, of the joint part which generate | occur | produces with a vibration or an impact. Generation of cracks can be suppressed.

  Application Example 6 A vibrator manufacturing method according to this application example is a vibrator manufacturing method according to the above application example, in which the support member or the support member and the second electrode are formed. A step of laminating one conductive layer, a step of removing at least a part of the first conductive layer, leaving a region where the support member is formed, and a second step of forming the support member and the second electrode. And laminating a conductive layer.

  According to this application example, the reinforcing region can be formed on the support member by selectively laminating the first conductive layer and the second conductive layer on the region where the support member is formed. As a result, the vibrator according to the application example described above can be easily manufactured.

  Application Example 7 A vibrator manufacturing method according to this application example is a vibrator manufacturing method according to the above application example, in which the support member and the conductive layer forming the second electrode are stacked. And a step of removing a part of the conductive layer leaving a region where the support member is formed.

  According to this application example, the conductive layer stacked in the region where the support member is formed is left without being selectively removed, so that the reinforcing region can be formed in the support member. As a result, the vibrator according to the application example described above can be easily manufactured.

  Application Example 8 An electronic apparatus according to this application example includes the vibrator according to the application example.

  According to this application example, a high-performance and inexpensive electronic device can be provided without degrading higher-performance characteristics as an electronic device, and by utilizing a vibrator with a high manufacturing yield and stability. can do.

(A): Side sectional view showing a MEMS vibrator as a vibrator according to the first embodiment, (b): a perspective view of the MEMS vibrator, and (c): a state of vibration of the movable upper electrode (second electrode). Sectional drawing. (A), (b): Side sectional view which shows the MEMS vibrator by a prior art. (A)-(f): Process drawing which shows the manufacturing method of a MEMS vibrator in order. FIG. 4A is a perspective view illustrating a configuration of a mobile personal computer as an example of an electronic apparatus, and FIG. 5B is a perspective view illustrating a configuration of a mobile phone as an example of an electronic apparatus. The perspective view which shows the structure of the digital still camera as an example of an electronic device. (A), (b): Side sectional view of a MEMS vibrator according to Modifications 1 and 2. (C): The conceptual diagram which shows the mode of a vibration of the movable upper electrode (2nd electrode) of the MEMS vibrator | oscillator which concerns on the modification 3. FIG. FIG. 9 is a process diagram illustrating a modification example of the MEMS vibrator manufacturing method in order as Modification Example 4;

  DESCRIPTION OF EMBODIMENTS Embodiments embodying the present invention will be described below with reference to the drawings. The following is one embodiment of the present invention and does not limit the present invention. In the following drawings, the scale may be different from the actual scale for easy understanding.

(Embodiment 1)
FIG. 1A is a side sectional view showing a MEMS vibrator 100 as a vibrator according to the first embodiment, and FIG. 1B is a perspective view thereof. Fig.1 (a) has shown the AA cross section of FIG.1 (b).
The MEMS vibrator 100 is a MEMS vibrator including a free-beam movable electrode on both ends formed by etching a sacrificial layer stacked on a main surface of a substrate. The wafer substrate 1 is a first electrode. The fixed lower electrode 20, the movable upper electrode 30 as the second electrode, the support member 40, and the like are included.
Note that the sacrificial layer is a layer that is removed by etching after forming necessary layers above and around it, and by removing the sacrificial layer, necessary gaps and cavities are formed between the upper and lower and surrounding layers. Or the necessary structures are released.

As a preferred example, a silicon substrate is used for the wafer substrate 1.
The fixed lower electrode 20, the movable upper electrode 30 and the support member 40 are formed on the first oxide film 11 and the nitride film 12 stacked on the wafer substrate 1.
Here, in the thickness direction of the wafer substrate 1, the direction in which the first oxide film 11 and the nitride film 12 are sequentially laminated on the main surface of the wafer substrate 1 is the upward direction, or as shown in FIG. It is described as a direction.

The fixed lower electrode 20 is a fixed electrode patterned in a rectangular shape, and is formed by patterning the lower conductive layer 13 stacked on the nitride film 12 by photolithography.
The movable upper electrode 30 is a rectangular plate-shaped movable electrode, and is formed by patterning the upper conductive layer 16 stacked via a sacrificial layer stacked on the lower conductive layer 13 by photolithography. Yes.
The movable upper electrode 30 is disposed so that the central region of the movable upper electrode 30 intersects and overlaps the fixed lower electrode 20 when the wafer substrate 1 is viewed in plan. The movable upper electrode 30 is supported on the main surface of the wafer substrate 1 by joining four points on the side surface in the longitudinal direction by two pairs of support members 40. A gap 25 is formed between the movable upper electrode 30 and the fixed lower electrode 20 and between the movable upper electrode 30 and the nitride film 12 by etching away the sacrificial layer.
For the lower conductive layer 13 and the upper conductive layer 16, conductive polysilicon is used as a preferred example, but the present invention is not limited to this.

The support member 40 is a substantially rectangular plate-like body obtained by patterning the upper conductive layer 16 by photolithography, and the longitudinal direction thereof is a direction substantially parallel to the main surface of the wafer substrate 1, and the lateral direction is The wafer substrate 1 is disposed so as to face the thickness direction (a direction substantially perpendicular to the main surface).
The lower surface of one end region in the longitudinal direction of the support member 40 is fixed to the wafer substrate 1 via the fixing portion 40 u, the nitride film 12, and the first oxide film 11. Further, the side surface of the other end portion in the longitudinal direction of the support member 40 is joined to the longitudinal side surface of the movable upper electrode 30.
Further, the four support members 40 support two pairs of support members 40 with the movable upper electrode 30 interposed therebetween. That is, the four support members 40 are positioned so that the side surfaces in the short direction (the other end of the support member 40) face each other, and the side surfaces in the short direction of the support members 40 are It is joined to the longitudinal side surface of the movable upper electrode 30.

The length in the short direction of the support member 40 (the width in the Z direction of the support member 40) is formed to be thicker than the thickness of the movable upper electrode 30, and is movable with the support member 40 at the bottom of the side surface in the short direction. The upper electrode 30 is joined. That is, the support member 40 has a region where the thickness of the support member 40 in the thickness direction (that is, the Z direction) of the wafer substrate 1 is thicker than the thickness of the movable upper electrode 30 in the Z direction (hereinafter referred to as a reinforcement region 40s). Further, as shown in FIG. 1A, the reinforcing region 40 s is a region in which the thickness of the support member 40 in the Z direction is thicker in the direction away from the main surface of the wafer substrate 1 than the thickness of the movable upper electrode 30 in the Z direction. It is trying to become.
Further, the joint portion between the support member 40 and the movable upper electrode 30 is formed so as to intersect with a radius of curvature R, as enlarged in the broken-line circle of FIG. The magnitude of the curvature radius R is not particularly specified, but it is preferable that the stress from the reinforcing region 40 s is not concentrated on the joint portion with the movable upper electrode 30 as described above.

FIG. 1C is a BB cross-sectional view of the movable upper electrode 30 shown in FIG. 1B, and shows how the movable upper electrode 30 vibrates.
In the MEMS vibrator 100, the movable upper electrode 30 vibrates due to an electrostatic force generated by an alternating voltage applied between the electrodes (between the fixed lower electrode 20 and the movable upper electrode 30). A resonance frequency signal unique to the vibrator is output. In FIGS. 1A to 1C, illustration of electric wiring connected to the fixed lower electrode 20 and the movable upper electrode 30 is omitted.
The movable upper electrode 30 has a central portion where the fixed lower electrode 20 and the movable upper electrode 30 overlap, and both end portions of the movable upper electrode 30 are antinodes of vibration, and has a vibration node 31 between the antinodes of vibration. Vibrate.

  The movable upper electrode 30 is supported by the support member 40 at the portion of the vibration node 31. Specifically, both ends of the vibration node 31 indicated by the one-dot chain line in FIG. 1B are supported by a pair of support members 40.

Here, a configuration example of the MEMS vibrator according to the prior art will be described.
2A and 2B are side sectional views showing a MEMS vibrator 99 according to the prior art.
Similar to the MEMS vibrator 100, the MEMS vibrator 99 is a MEMS vibrator including a free-beam movable electrode at both ends, and includes a wafer substrate 1, a fixed lower electrode 20, a movable upper electrode 30, a support member 409, and the like. Has been.
Unlike the support member 40, the support member 409 does not have the reinforcing region 40s. That is, the thickness of the support member 409 in the Z direction is the same as the thickness of the movable upper electrode 30 in the Z direction. Except for this point, the MEMS vibrator 99 is the same as the MEMS vibrator 100.

The support member 409 is formed of the same layer as the layer that forms the movable upper electrode 30, and is simultaneously formed by performing patterning by photolithography. Therefore, each thickness is substantially the same.
Generally, to cope with downsizing, thinning, power saving, high frequency, etc., the stiffness of the movable upper electrode and the support member is reduced, or the gap between the movable upper electrode and the fixed lower electrode is reduced. It is effective. However, as a result, as shown in FIG. 2B, in the MEMS vibrator 99, the movable upper electrode 30 is easily stuck to the fixed lower electrode 20 in the manufacturing process, and a sufficient manufacturing yield cannot be obtained. There was a problem. The MEMS vibrator 100 responds to such a problem with the above-described configuration.

Next, a method for manufacturing the MEMS vibrator 100 will be described.
FIGS. 3A to 3F are process diagrams sequentially showing a method for manufacturing the MEMS vibrator 100.
The method of manufacturing the MEMS vibrator 100 includes the step of laminating the first conductive layer 16a of the upper conductive layer 16 that forms the support member 40 or the support member 40 and the movable upper electrode 30, and the support member 40 is formed. A step of removing at least a portion of the first conductive layer 16a, and a step of laminating the second conductive layer 16b of the upper conductive layer 16 forming the support member 40 and the movable upper electrode 30. Including.
Hereinafter, specific description will be made with reference to FIGS. 3A to 3F in order.

FIG. 3A: A wafer substrate 1 is prepared, and a first oxide film 11 is laminated on the main surface. As a preferred example, the first oxide film 11 is formed of a LOCOS (Local Oxidation of Silicon) oxide film, which is a general element isolation layer of a semiconductor process, but depending on the generation of the semiconductor process, for example, STI (Shallow Trench Isolation). It may be an oxide film by the method.
Next, the nitride film 12 is laminated. The nitride film 12 is resistant to buffered hydrofluoric acid as an etchant and functions as an etching stopper.
Next, the lower conductive layer 13 is laminated on the nitride film 12. The lower conductive layer 13 is a polysilicon layer that constitutes the fixed lower electrode 20 and the fixed portion 40u, and is ion-implanted after lamination to give a predetermined conductivity.
Next, the lower conductive layer 13 is patterned by photolithography to form the fixed lower electrode 20 and the fixed portion 40u.

FIG. 3B: A CVD (Chemical Vapor Deposition) oxide film 14 is laminated and patterned by photolithography to form an opening 15 in which a part of the fixing portion 40u is exposed. The opening 15 is a part for fixing the support member 40 to the substrate, and is an area corresponding to the lower surface of one end region of the support member 40 to be formed later.
The CVD oxide film 14 is etched away later as a sacrificial layer, thereby forming a gap 25 between the fixed lower electrode 20 and the movable upper electrode 30 and between the movable upper electrode 30 and the nitride film 12.

  FIG. 3C: the first conductive layer 16a is stacked. The first conductive layer 16 a is a polysilicon layer and constitutes the first layer of the support member 40 or the upper conductive layer 16 that forms the support member 40 and the movable upper electrode 30.

  FIG. 3D: The first conductive layer 16a is patterned by photolithography to form a lower layer portion of the support member 40. Specifically, when the wafer substrate 1 is viewed in plan, the first conductive layer 16a is removed except for the region where the support member 40 is formed. A region corresponding to the lower surface of the one end region of the support member 40 is formed so as to be stacked on the fixed portion 40 u through the opening 15.

FIG. 3E: the second conductive layer 16b is stacked. The second conductive layer 16 b is the same polysilicon layer as the first conductive layer 16 a and constitutes the second layer of the upper conductive layer 16 that forms the support member 40 and the movable upper electrode 30. Next, the second conductive layer 16 b is patterned by photolithography to form the upper layer portion of the support member 40 and the movable upper electrode 30. Specifically, when the wafer substrate 1 is viewed in plan, the second conductive layer 16b is removed except for the region where the support member 40 and the movable upper electrode 30 are formed.
The first conductive layer 16a and the second conductive layer 16b are each ion-implanted after being laminated to have predetermined conductivity.

  By stacking and patterning the first conductive layer 16a and the second conductive layer 16b, the thickness of the support member 40 becomes the stack thickness of the first conductive layer 16a and the second conductive layer 16b, and the thickness of the movable upper electrode 30 is set to the second thickness. The thickness is only the conductive layer 16b. This difference in thickness forms the reinforcing region 40 s (FIG. 1A) of the support member 40.

FIG. 3F: The wafer substrate 1 is exposed to an etching solution, and the CVD oxide film 14 as a sacrificial layer is removed by etching, whereby the gap 25 between the fixed lower electrode 20 and the movable upper electrode 30 and the movable upper electrode 30 A gap 25 is formed between the nitride film 12 and the like. The MEMS vibrator 100 is formed by the above process.
Note that a MEMS structure including a vibrator, such as the MEMS vibrator 100, is preferably disposed in a reduced pressure space in order to exhibit and maintain good vibration characteristics. For this reason, a side wall that surrounds the MEMS vibrator 100, a clothing layer (sealing layer) that covers the space formed by the side wall, a surface protective layer, and the like are formed by a semiconductor manufacturing process including the above-described steps. It is preferable to arrange in a cavity maintained at a reduced pressure.

As described above, according to the vibrator and the method for manufacturing the vibrator according to the present embodiment, the following effects can be obtained.
The support member 40 that supports the movable upper electrode 30 having a region overlapping the fixed lower electrode 20 via the gap 25 has a reinforcing region 40 s in which the thickness of the support member 40 is larger than the thickness of the movable upper electrode 30 in the Z direction. Have. The reinforcement region 40s increases the rigidity of the support member 40 in the Z direction. As a result, even when an external force is applied in a direction in which the movable upper electrode 30 is brought closer to the fixed lower electrode 20, the movable upper electrode 30 becomes difficult to approach the fixed lower electrode 20. Therefore, for example, when the sacrificial layer (CVD oxide film 14) is removed by etching in order to form the movable upper electrode 30 and the fixed lower electrode 20, an etching solution or the like can be formed between the movable upper electrode 30 and the fixed lower electrode 20. Even when the surface tension of the cleaning liquid is applied, the sticking phenomenon that the movable upper electrode 30 adheres to the fixed lower electrode 20 is less likely to occur. As a result, yield reduction due to sticking can be suppressed.

  In addition, the movable upper electrode 30 is a vibration plate that bends and vibrates in the Z direction, and the bending vibration node portion (vibration node 31) of the movable upper electrode 30 is joined to the other end of the support member 40. Yes. Further, the rigidity of the support member 40 is increased in the Z direction by the reinforcing region 40s. Therefore, even if the rigidity of the support member 40 is increased and the stiffness is increased, the support member 40 supports the vibration node portion of the movable upper electrode 30 and therefore does not greatly disturb the vibration. That is, the sticking phenomenon can be suppressed by supporting the movable upper electrode 30 more effectively without adversely affecting the vibration characteristics.

  Further, the reinforcing region 40 s is configured by a thick region in a direction away from the main surface of the wafer substrate 1 with respect to the support member 40. With this configuration, the rigidity of the support member 40 can be increased without changing the size (distance) of the gap 25 between the movable upper electrode 30 and the fixed lower electrode 20. That is, the sticking phenomenon can be suppressed without deteriorating the characteristics as a vibrator.

  Further, the joint portion between the support member 40 and the movable upper electrode 30 is formed to intersect with a radius of curvature R. By comprising in this way, it is suppressed that the stress from the support member 40 concentrates on the joint part of the support member 40 and the movable upper electrode 30, Therefore The joint which generate | occur | produces with a vibration and an impact is suppressed. Generation of cracks in the portion can be suppressed.

[Electronics]
Next, an electronic apparatus to which the MEMS vibrator 100 as an electronic component according to an embodiment of the present invention is applied will be described with reference to FIGS. 4 (a), 4 (b), and FIG.

  FIG. 4A is a perspective view showing an outline of the configuration of a mobile (or notebook) personal computer as an electronic apparatus including an electronic component according to an embodiment 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 1000. The display unit 1106 is rotated with respect to the main body portion 1104 via a hinge structure portion. It is supported movably. Such a personal computer 1100 incorporates a MEMS vibrator 100 as an electronic component that functions as a filter, a resonator, a reference clock, and the like.

  FIG. 4B is a perspective view schematically showing a configuration of a mobile phone (including PHS) as an electronic apparatus including the electronic component according to the embodiment of the present invention. In this figure, a cellular phone 1200 is provided with a plurality of operation buttons 1202, an earpiece 1204 and a mouthpiece 1206, and a display unit 1000 is disposed between the operation buttons 1202 and the earpiece 1204. Such a cellular phone 1200 incorporates a MEMS vibrator 100 as an electronic component (timing device) that functions as a filter, a resonator, an angular velocity sensor, or the like.

FIG. 5 is a perspective view schematically illustrating a configuration of a digital still camera as an electronic apparatus including the electronic component according to the embodiment of the present invention. In this figure, connection with an external device is also simply shown. The digital still camera 1300 generates an imaging signal (image signal) by photoelectrically converting an optical image of a subject using an imaging element such as a CCD (Charge Coupled Device).
A display unit 1000 is provided on the back of a case (body) 1302 in the digital still camera 1300, and is configured to display based on an image pickup signal from the CCD. The display unit 1000 displays an object 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 1000 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 includes a MEMS vibrator 100 as an electronic component that functions as a filter, a resonator, an angular velocity sensor, or the like.

  As described above, a high-performance and inexpensive electronic device can be provided as an electronic device by utilizing the MEMS vibrator 100 that does not deteriorate the higher-performance characteristics and stabilizes the manufacturing yield. can do.

  Note that the MEMS vibrator 100 as an electronic component according to an embodiment of the present invention includes a personal computer (mobile personal computer) shown in FIG. 4A, a mobile phone shown in FIG. 4B, and a digital still camera shown in FIG. In addition, for example, an ink jet discharge device (for example, an ink jet printer), a laptop personal computer, a television, a video camera, a car navigation device, a pager, an electronic notebook (including a communication function), an electronic dictionary, a calculator, an electronic Game equipment, workstations, videophones, crime prevention TV monitors, electronic binoculars, POS terminals, medical equipment (eg electronic thermometers, blood pressure monitors, blood glucose meters, electrocardiogram measuring devices, ultrasonic diagnostic devices, electronic endoscopes), fish detection Machines, various measuring instruments, instruments (eg, vehicles, aircraft, ships Vessels such) can be applied to electronic devices such as flight simulators.

  Note that the present invention is not limited to the above-described embodiment, and various modifications and improvements can be added to the above-described embodiment. A modification will be described below. Here, the same components as those in the above-described embodiment are denoted by the same reference numerals, and redundant description is omitted.

(Modification 1)
FIG. 6A is a side sectional view of the MEMS vibrator 101 according to the first modification.
Similar to the MEMS vibrator 100, the MEMS vibrator 101 is a MEMS vibrator having a free-beam movable electrode at both ends, and includes a wafer substrate 1, a fixed lower electrode 20, a movable upper electrode 30, a support member 40a, and the like. Has been.
Unlike the support member 40, the support member 40a has a reinforcement region 40sa in which the position of the reinforcement region is different. In the MEMS vibrator 100, the reinforcing region 40 s is configured such that the thickness of the support member 40 in the Z direction is thicker in the direction away from the main surface of the wafer substrate 1 than the thickness of the movable upper electrode 30 in the Z direction. . On the other hand, in the MEMS vibrator 101, the reinforcing region 40sa has a region in which the thickness of the support member 40a in the Z direction is thicker in the direction closer to the main surface of the wafer substrate 1 than the thickness of the movable upper electrode 30 in the Z direction. It is trying to become. In other words, in the MEMS vibrator 100, the movable upper electrode 30 is supported by the lower part of the support member 40, whereas in the MEMS vibrator 101, the movable upper electrode 30 is supported by the upper part of the support member 40. Except for this point, the MEMS vibrator 101 is the same as the MEMS vibrator 100.

  As in the MEMS vibrator 101 according to this modification, in order to obtain a desired vibration characteristic, when there is a margin enough to arrange the reinforcing region 40sa in the size of the gap 25, the reinforcing region 40sa is moved to the movable upper portion. By positioning the electrode 30 below the position of the electrode 30, the support member can be reinforced without changing the thickness (height) of the MEMS vibrator 101.

(Modification 2)
FIG. 6B is a side sectional view of the MEMS vibrator 102 according to the second modification.
Similar to the MEMS vibrator 100, the MEMS vibrator 102 is a MEMS vibrator having a free-beam movable electrode at both ends, and includes a wafer substrate 1, a fixed lower electrode 20, a movable upper electrode 30, a support member 40b, and the like. Has been.
Unlike the support member 40, the support member 40b has a reinforcement region 40sb in which the shape of the reinforcement region is different. The shape of the reinforcing region 40 sb is such that the thickness in the Z direction of the reinforcing region 40 sb increases in the upward direction (away from the main surface of the wafer substrate 1) as the distance from the portion where the movable upper electrode 30 is joined (the other end of the support member 40 b). Direction). Except for this point, the MEMS vibrator 102 is the same as the MEMS vibrator 100.

  As in the present modification, the thickness in the Z direction of the reinforcing region 40 sb increases as the distance from the portion joined to the movable upper electrode 30 increases. By comprising in this way, since it suppresses that the stress from the support member 40b concentrates on the joint part of the support member 40b and the movable upper electrode 30, the joint which generate | occur | produces with a vibration or an impact is suppressed. The crack of a part can be decreased.

(Modification 3)
FIG. 6C is a conceptual diagram showing a state of vibration of the movable upper electrode 30 of the MEMS vibrator 103 (not shown) according to the third modification.
The MEMS vibrator 103 is a MEMS vibrator having a free-beam movable electrode at both ends similarly to the MEMS vibrator 100, and includes a wafer substrate 1, a fixed lower electrode 20, a movable upper electrode 30, a support member 40, and the like. Has been.
The MEMS vibrator 100 has been described on the assumption that the movable upper electrode 30 is supported by two pairs of support members 40 as shown in FIG. 1B, but the support members 40 are not limited to two pairs. . For example, as shown in FIG. 6C, when there are four vibration nodes 31, the structure may be supported by four pairs of support members 40. In other words, when there are three or more vibration nodes 31, a configuration in which the number of vibration nodes 31 is supported by pairs of support members 40 up to the number of vibration nodes 31 may be employed.

  As in the present modification, the movable upper electrode 30 is supported by the pair of support members at a plurality of locations, whereby the rigidity in the Z direction is further increased, so that the sticking phenomenon is effectively suppressed. In addition, since the movable upper electrode 30 is supported at both ends of the vibration node 31 of the movable upper electrode 30 by a pair of support members, the vibration characteristics are not greatly deteriorated.

(Modification 4)
FIGS. 7A to 7E are process diagrams sequentially showing modified examples of the method for manufacturing the MEMS vibrator 100 as the modified example 4. FIG.
The modification of this manufacturing method includes a step of laminating a conductive layer that forms the support member 40 and the movable upper electrode 30, a step of removing a part of the conductive layer while leaving a region where the support member 40 is formed, and Is included.
7A and 7B are the same as those in FIGS. 3A and 3B. Hereinafter, FIGS. 7C to 7E will be described in order.

  FIG. 7C: the first conductive layer 16c is stacked. The first conductive layer 16 c is a polysilicon layer, and is a layer that forms the support member 40 and the movable upper electrode 30. The step of laminating the first conductive layer 16c is the same as the step of laminating the first conductive layer 16a, but the thickness to be laminated is different. In the manufacturing method described in the first embodiment, as shown in FIG. 3E, the support member 40 is formed by laminating the first conductive layer 16a and the second conductive layer 16b. In the manufacturing method, the support member 40 is formed of the first conductive layer 16c.

  FIG. 7D: The first conductive layer 16c is patterned by photolithography to form a portion to be the movable upper electrode 30 and the support member 40. Specifically, when the wafer substrate 1 is viewed in plan, the first conductive layer 16c is removed except for the region where the movable upper electrode 30 and the support member 40 are formed. A region corresponding to the lower surface of the one end region of the support member 40 is formed so as to be stacked on the fixed portion 40 u through the opening 15.

  FIG. 7E: The remaining first conductive layer 16c is further patterned by photolithography to form a portion that becomes the movable upper electrode 30. Specifically, when the wafer substrate 1 is viewed in plan, the first conductive layer 16 c in the region of the movable upper electrode 30 excluding the region of the support member 40 is half-etched. Half etching ends when the thickness of the movable upper electrode 30 reaches a desired thickness.

  FIG. 7 (e): The wafer substrate 1 is exposed to an etching solution, and the CVD oxide film 14 as a sacrificial layer is removed by etching, whereby the gap 25 between the fixed lower electrode 20 and the movable upper electrode 30, A gap 25 is formed between the nitride film 12 and the like. The MEMS vibrator 100 is formed by the above process.

  According to the manufacturing method of the present modified example, the first conductive layer 16c stacked in the region where the support member 40 is formed is not selectively removed, so that the reinforcing region 40s can be formed in the support member 40. it can. As a result, the vibrator according to the application example described above can be easily manufactured.

  DESCRIPTION OF SYMBOLS 1 ... Wafer substrate, 11 ... 1st oxide film, 12 ... Nitride film, 13 ... Lower conductive layer, 14 ... CVD oxide film, 15 ... Opening, 16 ... Upper conductive layer, 16a, 16c ... 1st conductive layer, 16b ... Second conductive layer, 20 ... fixed lower electrode, 25 ... gap, 30 ... movable upper electrode, 31 ... vibration node, 40 ... support member, 40s ... reinforcing region, 40u ... fixed portion, 99, 100 ... MEMS vibrator, 409: Support member.

Claims (8)

A substrate,
A first electrode provided on a main surface of the substrate;
A support member having one end fixed to the substrate;
A second electrode joined to the other end of the support member and having a region overlapping the first electrode via a gap;
The vibrator has a reinforcing region in which the thickness of the support member in the thickness direction of the substrate is larger than the thickness of the second electrode in the thickness direction of the substrate. The second electrode is a diaphragm that bends and vibrates in the thickness direction of the substrate,
The vibrator according to claim 1, wherein a node portion of the flexural vibration of the second electrode is joined to the other end portion of the support member. Both ends of the bending vibration node portion of the second electrode are supported by a pair of the support members,
The vibrator according to claim 1, wherein the second electrode is supported by a plurality of the pair of support members.   The reinforcing region is a region where the thickness of the support member in the thickness direction of the substrate is thicker in the direction away from the main surface of the substrate than the thickness of the second electrode in the thickness direction of the substrate. The vibrator according to any one of claims 1 to 3.   5. The vibrator according to claim 1, wherein a thickness of the reinforcing region in a thickness direction of the substrate increases as the distance from the other end of the support member increases. . A method for manufacturing the vibrator according to claim 1, wherein:
Laminating the support member or the first conductive layer forming the support member and the second electrode;
Removing at least a portion of the first conductive layer leaving a region where the support member is formed;
Laminating a second conductive layer for forming the support member and the second electrode. A method for manufacturing the vibrator according to claim 1, wherein:
Laminating a conductive layer forming the support member and the second electrode;
And a step of removing a part of the conductive layer leaving a region where the support member is formed.   An electronic apparatus comprising the vibrator according to any one of claims 1 to 5.

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