JP6217108B2 - Manufacturing method of vibration element - Google Patents

Description

  The present invention relates to a method for manufacturing a vibration element.

  The AT-cut crystal resonator element is a thickness-shear vibration mode of the main vibration to be excited, and is suitable for miniaturization and high frequency, and exhibits a cubic curve with excellent frequency temperature characteristics. Used in many ways. A manufacturing method described in Patent Document 1 is known as a manufacturing method of such an AT-cut quartz crystal resonator.

In the method of manufacturing an AT-cut quartz resonator described in Patent Document 1, first, a large number of concave portions serving as vibration portions are formed by forming a large number of concave portions on the surface of a crystal wafer. In this state, the thickness of each bottom portion varies, and there is also a vibrating portion that does not have a desired thickness. Therefore, next, the thickness of each vibration part is adjusted independently so that the thickness variation of the vibration part is eliminated and the thickness of each vibration part becomes a desired thickness. Specifically, first, a mask that covers a thick region other than the depression is disposed. Next, etching is performed by dropping an etching solution into a vibrating portion (concave portion) that is not a predetermined thickness by using a dispenser to obtain a desired thickness. By independently controlling the etching time for each vibration part, the thickness of the vibration part, which has been separated, can be adjusted to a desired thickness. Finally, a large number of vibration elements can be obtained by dividing each vibration part into pieces.
However, in such a manufacturing method, since the etching time must be accurately controlled for each vibration part, the manufacture of the vibration element becomes complicated. In addition, since the mask also has a lifetime and costs such as mask replacement are required, the manufacturing cost of the vibration element increases.

Japanese Patent Laid-Open No. 06-334461

  An object of the present invention is to provide a method for manufacturing a vibration element that can exhibit desired vibration characteristics easily and at low cost.

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 forms or application examples.
[Form 1]
In the manufacturing method of the resonator element according to the invention, at least one main surface of the substrate is etched ,
The first concave portion is formed on the one main surface to form a first thin portion thinner than the substrate, and the second concave portion is formed on the one main surface to form the substrate. A thin part forming step of forming a second thin part having a smaller thickness than ,
Placing the substrate between the upper and lower electrodes;
Supplying a processing gas between the upper electrode and the lower electrode and applying a voltage to generate plasma,
The surface of the first thin portion is locally moved so that the thickness of the first thin portion is within a predetermined range by relatively moving the region where the plasma is generated and the substrate. Plasma treatment,
The surface of the second thin portion is locally moved so that the thickness of the second thin portion is within the predetermined range by relatively moving the region where the plasma is generated and the substrate. And a thickness adjusting step for plasma processing .
Accordingly, it is possible to manufacture a vibration element that can exhibit desired vibration characteristics easily and at low cost.
[Form 2]
In the manufacturing method of the vibration element of the present invention, after the previous KiAtsu adjusting step,
A thick part thicker than the first thin part is located along at least a part of the outer edge of the first recessed part, and the thick part is located along at least a part of the outer edge of the second recessed part. It is preferable to include a singulation step of dividing the substrate into pieces so that a thick portion thicker than the second thin portion is located .
Accordingly, it is possible to manufacture a vibration element that can exhibit desired vibration characteristics easily and at low cost.
[Form 3]
In the method for manufacturing a vibration element according to the aspect of the invention, it is preferable that in the thin-walled portion forming step, the first concave portion and the second concave portion are formed by etching both main surfaces of the substrate.
Thereby, the depth of the first recessed portion and the second recessed portion is reduced, that is, between one main surface and the surfaces of the first thin portion and the second thin portion on the one main surface side. Therefore, the first concave portion and the second concave portion can be formed with higher accuracy.
[Form 4]
In the method for manufacturing a vibration element according to the aspect of the invention, it is preferable that the etching is wet etching.
Thereby, a thin part can be formed easily, accurately and at low cost.
[Form 5]
In the method for manufacturing a resonator element according to the aspect of the invention, the thickness adjusting step includes the first thin portion and the second thin portion so that the resonance characteristics of the first thin portion and the second thin portion are stabilized. It is preferable to plasma-treat the surface of the part .
As a result, it is possible to manufacture a resonator element having stable resonance characteristics.
[Form 6]
In the manufacturing method of the vibration element of the present invention, the process gas-law contains at least one fluorine atom-containing compound gas and chlorine atom-containing compound gas and is preferred.
Accordingly, it is possible to manufacture a vibration element that can exhibit desired vibration characteristics easily and at low cost.
[Form 7]
In the method for manufacturing a vibration element according to the aspect of the invention, it is preferable that a step of forming electrodes on the first thin portion and the second thin portion is included after the thickness adjusting step.
Thereby, manufacture of a vibration element can be performed more efficiently.
[Form 8]
In the method for manufacturing a vibration element according to the aspect of the invention, the first distance in the thickness direction of the substrate between the one main surface and the surface of the first thin portion on the one main surface side, and the one It is preferable that the second distance in the thickness direction between the main surface and the surface of the second thin portion on the one main surface side is 30 μm or more and 200 μm or less , respectively .
Thereby, the depth of the first recessed portion and the second recessed portion is reduced, that is, between one main surface and the surfaces of the first thin portion and the second thin portion on the one main surface side. Therefore, the first recessed portion and the second recessed portion can be formed with higher accuracy in the thin portion forming step.
[Form 9]
In the method for manufacturing a vibration element according to the aspect of the invention, it is preferable that the first distance and the second distance are 50 μm or more and 100 μm or less, respectively .
Thereby, the depth of the first recessed portion and the second recessed portion is made sufficiently shallow, that is, one main surface and the surfaces of the first thin portion and the second thin portion on the one main surface side. Since the distance between the two can be sufficiently shortened, the first recessed portion and the second recessed portion can be formed with higher accuracy in the thin portion forming step.
[Application Example 1]
The method for manufacturing a vibration element according to the present invention includes a step of forming a recess in at least one main surface of the substrate by etching, and forming a thin portion having a thickness smaller than that of the substrate.
Adjusting the thin portion to a predetermined thickness by plasma treatment.
Accordingly, it is possible to manufacture a vibration element that can exhibit desired vibration characteristics easily and at low cost.

[Application Example 2]
The method for manufacturing a resonator element of the present invention includes a step of forming a plurality of concave portions on at least one main surface of a substrate by etching to form a thin portion having a thickness smaller than the plurality of substrates, by etching,
Adjusting the thickness so as to align the plurality of thin-walled portions with a predetermined thickness by plasma treatment; and
An individualization step of dividing each thin portion into individual pieces such that a thick portion thicker than the thin portion is positioned along at least a part of an outer edge of the thin portion. And
Accordingly, it is possible to manufacture a vibration element that can exhibit desired vibration characteristics easily and at low cost.

[Application Example 3]
In the method for manufacturing a vibration element according to the aspect of the invention, it is preferable that in the step of forming the thin portion, the recessed portion is formed so as to overlap both main surfaces of the substrate in plan view.
Thereby, since the depth of each recessed part can be made shallow, a recessed part can be formed more accurately.

[Application Example 4]
In the method for manufacturing a vibration element according to the aspect of the invention, it is preferable that in the step of adjusting the thin portion to a predetermined thickness, the surface of the thin portion is plasma-treated so that the resonance characteristics of the thin portion are stabilized.
As a result, it is possible to manufacture a resonator element having stable resonance characteristics.
[Application Example 5]
In the method for manufacturing a vibration element according to the aspect of the invention, it is preferable to include a step of forming an electrode on the thin portion after the step of adjusting the thickness.
Thereby, manufacture of a vibration element can be performed more efficiently.

[Application Example 6]
In the method for manufacturing a vibration element according to the aspect of the invention, it is preferable that the depth of the recessed portion formed in the step of forming the thin portion is 30 μm or more and 200 μm or less.
Thereby, since the depth of a recessed part can be made shallow, a recessed part can be formed more accurately in the said thin part formation process.

[Application Example 7]
In the method for manufacturing a resonator element according to the aspect of the invention, it is preferable that the depth of the recessed portion is 50 μm or more and 100 μm or less.
Thereby, since the depth of a recessed part can be made shallow enough, a recessed part can be formed more accurately in the said thin part formation process.

It is a perspective view of the structural example of a vibration element. FIG. 2 is a plan view of the vibration element shown in FIG. 1. It is a figure explaining the relationship between an AT cut quartz substrate and the crystal axis of quartz. It is a side view which shows the state which fixed the vibration element shown in FIG. 1 to the target object. FIG. 6 is a perspective view illustrating another configuration example of the vibration element illustrated in FIG. 1. FIG. 8 is a cross-sectional view for explaining the method for manufacturing the vibration element shown in FIG. 1. FIG. 8 is a cross-sectional view for explaining the method for manufacturing the vibration element shown in FIG. 1. It is a figure which shows an example of a plasma processing apparatus. FIG. 8 is a cross-sectional view for explaining the method for manufacturing the vibration element shown in FIG. 1. FIG. 8 is a cross-sectional view for explaining the method for manufacturing the vibration element shown in FIG. 1. It is a top view which shows the other structural example of a vibration element. It is a top view which shows the other structural example of a vibration element. It is a top view which shows the other structural example of a vibration element. It is a perspective view which shows the other structural example of a vibration element. It is sectional drawing for demonstrating the manufacturing method of the vibration element shown in FIG. It is sectional drawing which shows the structural example of a vibrator | oscillator. It is sectional drawing which shows the structural example of an oscillator. It is a perspective view which shows the structure of a mobile type (or notebook type) personal computer. It is a perspective view which shows the structure of a mobile telephone (PHS is also included). It is a perspective view which shows the structure of a digital still camera. It is a perspective view which shows the motor vehicle as an example of a mobile body.

Hereinafter, a method for manufacturing a vibration element according to the present invention will be described in detail based on preferred embodiments shown in the drawings.
<First Embodiment>
1 is a perspective view showing a configuration example of a vibrating element, FIG. 2 is a plan view of the vibrating element shown in FIG. 1, and FIG. 3 is a diagram for explaining the relationship between an AT-cut quartz substrate and a crystal axis of quartz. 4 is a side view showing a state in which the vibration element shown in FIG. 1 is fixed to an object, FIG. 5 is a perspective view showing another configuration example of the vibration element shown in FIG. 1, and FIG. 6 and FIG. FIG. 8 is a diagram showing an example of a plasma processing apparatus, and FIGS. 9 and 10 are respectively for explaining a method for manufacturing the vibration element shown in FIG. 1. FIG.

1-1. Prior to describing the manufacturing method of the vibration element of the present invention, the vibration element manufactured by the manufacturing method of the vibration element of the present invention will be described.
As shown in FIGS. 1 and 2, the vibration element 1 includes a piezoelectric substrate 2 and an electrode 3 formed on the piezoelectric substrate 2.

(Piezoelectric substrate)
The piezoelectric substrate 2 is a plate-shaped quartz substrate. Here, the crystal that is the material of the piezoelectric substrate 2 belongs to the trigonal system, and has crystal axes X, Y, and Z orthogonal to each other as shown in FIG. The X axis, the Y axis, and the Z axis are referred to as an electric axis, a mechanical axis, and an optical axis, respectively. The piezoelectric substrate 2 of the present embodiment is a “rotated Y-cut quartz substrate” cut along a plane obtained by rotating the XZ plane around the X axis by a predetermined angle θ, for example, rotated by θ = 35 ° 15 ′. The substrate cut out along the flat surface is referred to as an “AT-cut quartz substrate”. By using such a quartz substrate, the vibration element 1 having excellent temperature characteristics is obtained.

However, the piezoelectric substrate 2 is not limited to the AT-cut piezoelectric substrate as long as the thickness-shear vibration can be excited. For example, a BT-cut piezoelectric substrate may be used. In addition to the quartz substrate, various piezoelectric substrates such as lithium niobate and lithium tantalate may be used as the piezoelectric substrate 2.
Hereinafter, the Y axis and the Z axis rotated around the X axis corresponding to the angle θ are referred to as a Y ′ axis and a Z ′ axis. That is, the piezoelectric substrate 2 has a thickness in the Y′-axis direction and has a spread in the XZ ′ plane direction.

  In plan view, the piezoelectric substrate 2 has a long shape in which the direction along the X axis is a long side and the direction along the Z ′ axis is a short side. The piezoelectric substrate 2 has the −X axis direction as the distal end side and the + X axis direction as the proximal end side. When the maximum length L in the direction along the X axis of the piezoelectric substrate 2 is set to W and the maximum width in the direction along the Z ′ axis is set to W, L / W is not particularly limited. It is preferably about 1.4.

As shown in FIGS. 1 and 2, the piezoelectric substrate 2 includes a vibrating portion 21 including a thin vibrating region (region in which vibration energy is confined) 219, and the vibrating portion 21, and is thicker than the vibrating region 219. And a thick portion 22.
The vibrating portion 21 is offset toward the −X axis direction side and the −Z ′ axis direction side with respect to the center of the piezoelectric substrate 2, and a part of the outer edge thereof is exposed from the thick portion 22. In plan view of the vibration element 1, the area of the vibration part 21 is preferably ½ or less of the area of the piezoelectric substrate 2. Thereby, since the thick part 22 with high mechanical strength can be formed sufficiently wide, the rigidity of the vibration part 21 can be sufficiently ensured.

  The vibration part 21 is spaced apart in the X-axis direction (vibration direction of thickness-shear vibration) and extends in the Z′-axis direction in a plan view of the vibration element 1, and Z ′ A third outer edge 213 and a fourth outer edge 214 are spaced apart in the axial direction and extend in the X-axis direction. Of the first and second outer edges 211 and 212, the first outer edge 211 is located on the + X axis side, and the second outer edge 212 is located on the −X axis side. Of the third and fourth outer edges 213 and 214, the third outer edge 213 is located on the + Z′-axis side, and the fourth outer edge 214 is located on the −Z′-axis side. The third outer edge 213 connects the ends of the first and second outer edges 211 and 212 on the + Z ′ axis side, and the fourth outer edge 214 is the −Z ′ axis side of the first and second outer edges 211 and 212. The ends of are connected.

As shown in FIG. 1, the surface of the thick wall portion 22 (the main surface on the + Y′-axis direction side) protrudes more toward the + Y′-axis direction side than the surface of the vibration portion 21 (the main surface on the + Y′-axis direction side). Is provided. On the other hand, the back surface (the main surface on the −Y ′ axis direction side) of the thick portion 22 is provided on the same plane as the back surface (the main surface on the −Y ′ axis direction side) of the vibration unit 21.
The thick part 22 includes a first thick part 23 disposed along the first outer edge 211 and a second thick part disposed along the third outer edge 213 and connected to the first thick part 23. 24. Therefore, the thick portion 22 has a structure bent along the vibration portion 21 in a plan view, and has a substantially L shape. On the other hand, the thick part 22 is not formed on the second outer edge 212 and the fourth outer edge 214 of the vibration part 21, and the second and fourth outer edges 212 and 214 are exposed from the thick part 22. . As described above, the thick portion 22 is partially provided on the outer edge of the vibration portion 21 so as to be substantially L-shaped, and is not provided along the second outer edge 212 and the fourth outer edge 214, whereby the vibration element 1 (vibration portion 21). It is possible to reduce the mass of the vibration element 1 on the tip side while maintaining the rigidity. Further, the vibration element 1 can be reduced in size.

  Here, by providing the first thick part 23 on the + X-axis side with respect to the vibration part 21, compared to the case where it is provided on the −X-axis side, the width of the inclined part 231 (the length in the X-axis direction) to be described later. Can be shortened. Similarly, by providing the second thick portion 24 on the + Z′-axis side with respect to the vibration portion 21, the width (Z′-axis) of the inclined portion 241 to be described later is compared with the case where it is provided on the −Z′-axis side. Direction length) can be shortened. Therefore, according to such a thick portion 22, the vibration element 1 can be downsized.

  The first thick portion 23 is connected to the first outer edge 211, and is connected to an inclined portion (residue portion) 231 whose thickness gradually increases in the + X-axis direction, and an edge of the inclined portion 231 on the + X-axis direction side. And a thick portion main body 232 having a substantially constant thickness. Similarly, the second thick portion 24 is connected to the third outer edge 213 and has an inclined portion (residue portion) 241 that gradually increases in thickness toward the + Z′-axis direction, and the + Z′-axis direction side of the inclined portion 241. And a thick portion main body 242 having a substantially constant thickness connected to the edge. Further, a mount portion 29 is provided on the surface of the thick portion main body 232 of the first thick portion 23, and as shown in FIG. Used to fix the object 62.

(electrode)
The electrode 3 has a pair of excitation electrodes 31 and 32, a pair of pad electrodes 33 and 34, and a pair of extraction electrodes 35 and 36. The excitation electrode 31 is formed on the surface of the vibration region 219. On the other hand, the excitation electrode 32 is disposed on the back surface of the vibration region 219 so as to face the excitation electrode 31. The excitation electrodes 31 and 32 are each substantially rectangular with the X-axis direction as the long side and the Z′-axis direction as the short side.

  The excitation electrodes 31 and 32 have a similar shape, and the excitation electrode 32 on the back side is formed larger than the excitation electrode 31 on the front side. Further, the excitation electrode 31 is included in the excitation electrode 32 in a plan view of the vibration element 1. In other words, the entire region of the excitation electrode 31 is located in the excitation electrode 32 without overlapping the outer edges. Thereby, a desired vibration characteristic can be exhibited stably.

The pad electrode 33 is formed on the mount portion 29 on the surface of the thick portion main body 232. On the other hand, the pad electrode 34 is formed on the back surface of the thick portion main body 232 so as to face the pad electrode 33. The excitation electrode 31 and the pad electrode 33 are electrically connected by the extraction electrode 35. On the other hand, the excitation electrode 32 and the pad electrode 34 are electrically connected by the extraction electrode 36. The extraction electrodes 35 and 36 are provided so as not to overlap with each other via the piezoelectric substrate 2. Thereby, the electrostatic capacitance between the extraction electrodes 35 and 36 can be suppressed.
Such an electrode 3 can be composed of, for example, a metal film in which an alloy mainly composed of Au (gold) is laminated on an underlayer such as Cr (chromium) or Ni (nickel).

  The vibration element 1 has been described above. In the vibration element 1, the vibration part 21 is formed by forming a recessed part on the + Y′-axis side of the piezoelectric substrate 2, and the thick part 22 is positioned on the + X-axis side with respect to the vibration part 21. Although it is configured by the meat portion 23 and the second thick portion 24 located on the + Z ′ axis side, the vibration element 1 may be configured such that it is turned upside down. That is, as shown in FIG. 5, the oscillating portion 21 is formed by forming a recessed portion on the −Y′-axis side of the piezoelectric substrate 2, and the thick portion 22 is further on the + X-axis side with respect to the oscillating portion 21. You may be comprised by the 1st thick part 23 located and the 2nd thick part 24 located in the -Z 'axis side. Even with such a configuration, it is possible to achieve the same effect as the present embodiment (particularly, the effect of narrowing the width of the inclined portions 231 and 241).

1-2. Next, a method for manufacturing the vibration element 1 will be described.
The manufacturing method of the vibration element 1 includes a thin portion forming step of obtaining a plurality of thin portions 204 by forming a plurality of recessed portions 203 on one main surface of the piezoelectric substrate (substrate) 20 by wet etching, and plasma processing. A thickness adjusting step for flattening and thinning the plurality of thin portions 204 and aligning the plurality of thin portions 204 to a predetermined thickness, and a piece for dividing the plurality of piezoelectric substrates 2 formed in the piezoelectric substrate 20 into pieces. And an electrode forming step of forming the electrode 3 on the singulated piezoelectric substrate 2.

(Thin wall formation process)
First, as shown in FIG. 6A, a piezoelectric substrate (substrate) 20 which is an AT-cut quartz wafer is prepared. The piezoelectric substrate 20 includes a plurality of regions T3 that are separated into pieces as the piezoelectric substrate 2. Next, as shown in FIG. 6B, a laminate of a chromium (Cr) layer and a gold (Au) layer is formed on both main surfaces 201 and 202 of the piezoelectric substrate 20 by a film forming apparatus such as sputtering. A mask M is formed. Next, a resist film R having a plurality of openings R1 corresponding to the recessed portions is formed on the mask M by using a photolithography technique and an etching technique. Next, the portion of the mask M exposed from each opening R1 is removed by aqua regia, for example, to form a mask M having a plurality of openings M1 corresponding to each region T3, as shown in FIG. 6C. .

  Next, as shown in FIG. 7A, the piezoelectric substrate 20 is wet-etched (half-etched) through the opening M1 of the mask M using an etching solution (for example, a mixed solution of hydrofluoric acid and ammonium fluoride). And a plurality of recesses 203 are formed on the main surface 201 of the piezoelectric substrate 20. Thereby, a large number of thin portions 204 are formed. Finally, as shown in FIG. 7B, the mask M and the resist film R are removed using aqua regia, for example. By performing this process by wet etching, the thin portion 204 can be formed easily, accurately, and at low cost. The thin portion 204 is a portion that will later become the vibration portion 21, and at this time, the thickness is slightly larger than the thickness of the vibration portion 21.

  The depth d of the recessed portion 203 is not particularly limited, but is preferably 30 μm or more and 200 μm or less, and more preferably 50 μm or more and 100 μm or less. In wet etching, the smaller the etching amount, the smaller the error of the depth d. Therefore, by setting the numerical value range, it is possible to form the plurality of thin portions 204 with higher accuracy.

(Thickness adjustment process)
Here, the piezoelectric substrate 20 is cut into a plate shape from a crystal, and then the surface is polished by polishing or the like. Therefore, the surface layer of the piezoelectric substrate 20 may be subject to mechanical damage such as cracking and cleavage due to stress applied during the polishing process. If mechanical damage is incurred, the etching rate of the damaged part greatly deviates from the normal part of the non-damaged etching rate, and the above-mentioned thin portion 204 is formed with high accuracy. May not be possible. In other words, an error may occur in the thickness between the plurality of thin-walled portions 204 (see FIGS. 7A and 7B. In FIGS. 7A and 7B, the thickness is exaggerated. ) Further, although not shown in the drawing, there is a case in which the thickness varies in one thin portion 204, and uneven undulation is generated on the surface of the thin portion. In this case, there is a problem that the resonance characteristics of the thin wall portion are disturbed and not stable, and the resonance frequency is not stable.

  Therefore, in this step, as shown in FIG. 7C, the thickness of the plurality of thin portions 204 is made uniform, and the thickness is within a predetermined range so that the resonance frequency of each thin portion 204 is stabilized. Thereby, the vibrating part 21 is constituted by the thin part 204. This step is performed by plasma processing (PCVM: Plasma Chemical Vaporizing Machining). Thereby, planarization of the piezoelectric substrate 20 can be performed easily, accurately, and at low cost.

Hereinafter, an example of PCVM will be described. Hereinafter, for convenience of explanation, the three axes orthogonal to each other are referred to as an a-axis, a b-axis and a c-axis. In addition, the apparatus used for PCVM is not limited to what is shown below.
8 includes an upper electrode 911, a lower electrode 912 provided on the NC stage 940, a processing gas supply unit 920 that supplies a processing gas between the upper electrode 911 and the lower electrode 912, and the like. A high frequency power source 930 for applying a voltage between the upper electrode 911 and the lower electrode 912, a moving device 950 for moving the upper electrode 911, a processing gas supply means 920, a high frequency power source 930, an NC stage 940, a moving device 950, etc. Control means 960 for controlling the operation.

  In the plasma processing apparatus 900, a processing gas is supplied to the main surface 201 by the processing gas supply means 920 in a state where the piezoelectric substrate 20 is placed on the lower electrode 912 with the main surface 201 on which the recessed portion 203 is formed facing upward. While being supplied, a voltage is applied between the upper electrode 911 and the lower electrode 912 by the high-frequency power source 930 to activate the processing gas to generate plasma, and the plasma generation region T1 in which this plasma is generated and the piezoelectric substrate 20 Are moved relatively by the NC stage 940 (for example, meandering so as to move in the b direction while reciprocating in the a direction), and the surface of each thin portion 204 is locally and continuously moved by the plasma. Thus, an apparatus for plasma processing.

The processing gas supply means 920 has a nozzle 921 and supplies a mixed gas obtained by mixing a carrier gas and a processing gas from the nozzle 921 to the surface of the thin portion 204. Examples of the processing gas include fluorine atom-containing compound gases such as CF ₄ , C ₂ F ₆ , C ₃ F ₆ , C ₄ F ₈ , CClF ₃ , SF ₆ , and chlorine atoms such as Cl ₂ , BCl ₃ , CCl _4, etc. Various halogen-based gases such as contained compound gas are used. As the carrier gas, for example, a rare gas such as He, Ne, Ar, or Xe can be used. These can be used alone or in a mixed form of two or more. The carrier gas refers to a gas introduced for starting discharge and maintaining discharge.

  The NC stage 940 can move the lower electrode 912 in the a-axis direction and the b-axis direction. The NC stage 940 is configured to be able to adjust the moving speed, stop time, and the like of the lower electrode 912. On the other hand, the moving device 950 can move the upper electrode 911 in the c-axis direction. Therefore, the gap distance between the upper electrode 911 and the main surface 201 can be adjusted by the moving device 950.

  The control means 960 equalizes the thickness of the plurality of thin portions 204 based on the shape data of each recessed portion 203 (thin portion 204) created in advance, the etching rate obtained using a test piece or the like in advance, In addition, the processing plan data (the movement pattern of the piezoelectric substrate 20 with respect to the upper electrode 911, the movement speed when passing through the plasma generation region T1 in each part of the piezoelectric substrate 20 and the upper part) for making the thickness of each thin portion 204 within a predetermined range. A distance between the electrode 911 (that is, data including an etching amount in each portion of the thin portion 204) and the like is created. Then, the control unit 960 controls the operation of each part (processing gas supply unit 920, high frequency power source 930, NC stage 940, moving device 950, etc.) of the plasma processing apparatus 900 based on the created processing plan data. As a result, the thickness of the plurality of thin portions 204 is made uniform, and the thickness of each thin portion 204 is within a predetermined range.

(Individualization process)
Next, as shown in FIG. 9A, a laminate of a chromium (Cr) layer and a gold (Au) layer is formed on both main surfaces 201 and 202 of the piezoelectric substrate 20 by a film forming apparatus such as sputtering. A mask M ′ is formed. Next, using a photolithography technique and an etching technique, a resist film R ′ having an opening R1 ′ corresponding to a region other than the region T3 is formed on the mask M ′. Next, a portion of the mask M ′ exposed from the opening R1 ′ is removed with aqua regia etc. to obtain a mask M ′ having an opening M1 ′ as shown in FIG. 9B. Next, the piezoelectric substrate 20 is wet-etched through the opening M1 ′ of the mask M ′ using an etching solution (for example, a mixed solution of hydrofluoric acid and ammonium fluoride), as shown in FIG. 9C. Then, the plurality of piezoelectric substrates 2 are separated from the piezoelectric substrate 20.
However, the singulation method is not limited to the wet etching as described above, and may be performed by, for example, dicing (cutting with a dicing saw).

(Electrode formation process)
Next, for example, after removing the mask M ′ and the resist film R ′ using aqua regia etc., as shown in FIG. 10A, the surface of the piezoelectric substrate 2 is coated with chromium by a film forming apparatus such as sputtering. A metal film 30 that is a laminate of a (Cr) layer and a gold (Au) layer is formed. The metal film 30 is a film that becomes the electrode 3. Next, an opening R1 ″ corresponding to a region other than the electrode 3 (excitation electrodes 31, 32, pad electrodes 33, 34, and extraction electrodes 35, 36) is formed on the metal film 30 by using a photolithography technique and an etching technique. A resist film R ″ is formed. Next, the portion of the metal film 30 exposed from the opening R1 ″ is removed using aqua regia, for example. As a result, the electrode 3 is formed as shown in FIG.
Then, for example, by removing the resist film R ″ using aqua regia, the vibration element 1 is obtained as shown in FIG.

  According to such a manufacturing method, the vibration element 1 in which the thickness t of the vibration part 21 is equal to each other and the thickness t is a desired thickness can be manufactured easily and at low cost. In other words, it is possible to manufacture a plurality of vibration elements 1 having the same vibration characteristics (for example, equivalent circuit constants) and satisfying desired vibration characteristics of each individual with a high yield. In particular, in the present embodiment, since a plurality of vibration elements 1 are manufactured from one piezoelectric substrate 20, the manufacturing cost can be further reduced.

  In the manufacturing method of the resonator element 1 according to the present embodiment, the electrode forming process is performed after the singulation process. The electrode forming process is performed prior to the singulation process, that is, the recess forming process. It may be carried out between the singulation process. Also, a part of the electrode formation process (formation of excitation electrodes 31 and 32, pad electrodes 33 and 34 and extraction electrodes 35 and 36) is performed prior to the individualization process, and the rest is individualized. You may implement after a process.

Second Embodiment
FIG. 11 is a plan view illustrating another configuration example of the vibration element.
Hereinafter, the manufacturing method of the resonator element according to the second embodiment will be described focusing on the differences from the first embodiment described above, and description of similar matters will be omitted.
The second embodiment of the present invention is the same as the first embodiment described above except that the configuration of the vibration element to be manufactured is different. In addition, the same code | symbol is attached | subjected to the structure similar to 1st Embodiment mentioned above.

  As shown in FIG. 11, in the vibration element 1 </ b> A of the present embodiment, the thick portion 22 is further provided on the second outer edge 212 of the vibration portion 21 in addition to the first thick portion 23 and the second thick portion 24. The third thick portion 25 is disposed along the second thick portion 24 and is connected to the second thick portion 24. Therefore, the thick portion 22 has a substantially U shape along the vibrating portion 21. The thick part 22 is not formed along the fourth outer edge 214 of the vibration part 21, and the fourth outer edge 214 is exposed from the thick part 22. Thus, by making the thick portion 22 substantially U-shaped, the vibration element 1 can be reduced in size, and the rigidity of the vibration element 1 (vibration part 21) can be further increased, which is unnecessary. Spurious generation can be effectively prevented.

The third thick portion 25 is connected to the second outer edge 212, and has an inclined portion (residue portion) 251 whose thickness gradually increases in the −X axis direction, and an end edge on the −X axis direction side of the inclined portion 251. A thick portion main body 252 having a substantially constant thickness is provided.
Also according to the second embodiment, the same effects as those of the first embodiment described above can be exhibited.

<Third Embodiment>
FIG. 12 is a plan view illustrating another configuration example of the vibration element.
Hereinafter, the manufacturing method of the resonator element according to the third embodiment will be described focusing on the differences from the first embodiment described above, and description of similar matters will be omitted.
The third embodiment of the present invention is the same as the second embodiment described above except that the configuration of the vibration element to be manufactured is different. In addition, the same code | symbol is attached | subjected to the structure similar to 2nd Embodiment mentioned above.

  As shown in FIG. 12, in the vibration element 1 </ b> B according to the present embodiment, the thick portion 22 includes a vibrating portion in addition to the first thick portion 23, the second thick portion 24, and the third thick portion 25. 21 has a fourth thick portion 26 that is disposed along the fourth outer edge 214 and connected to the first and third thick portions 23 and 25. Therefore, the thick part 22 has a substantially square shape along the entire circumference of the vibration part 21, and the outer edge of the vibration part 21 is not exposed from the thick part 22. Thus, by making the thick part 22 into a substantially square shape, the rigidity of the vibration element 1 (vibration part 21) can be further increased, and the occurrence of unnecessary spurious can be effectively prevented.

The fourth thick portion 26 is connected to the fourth outer edge 214 and has an inclined portion (residue portion) 261 whose thickness gradually increases in the −Z′-axis direction, and an end of the inclined portion 261 on the −Z′-axis direction side. A thick portion main body 262 having a substantially constant thickness connected to the edge is provided.
Also according to the third embodiment, the same effects as those of the first embodiment described above can be exhibited.

<Fourth embodiment>
FIG. 13 is a plan view illustrating another configuration example of the vibration element.
Hereinafter, the manufacturing method of the vibration element according to the fourth embodiment will be described focusing on the differences from the first embodiment described above, and description of similar matters will be omitted.
The fourth embodiment of the present invention is the same as the third embodiment described above except that the configuration of the vibration element to be manufactured is different. In addition, the same code | symbol is attached | subjected to the structure similar to 3rd Embodiment mentioned above.

As shown in FIG. 13, in the vibration element 1C of the present embodiment, the third thick portion 25 is omitted from the third embodiment described above. That is, the thick part 22 has a first thick part 23, a second thick part 24, and a fourth thick part 26. Therefore, the thick part 22 has a substantially U shape along the vibration part 21, and the second outer edge 212 of the vibration part 21 is exposed from the thick part 22. Thus, by making the thick portion 22 substantially U-shaped, the vibration element 1 can be reduced in size, and the rigidity of the vibration element 1 (vibration part 21) can be further increased, which is unnecessary. Spurious generation can be effectively prevented.
According to the fourth embodiment, the same effect as that of the first embodiment described above can be exhibited.

<Fifth Embodiment>
FIG. 14 is a perspective view illustrating another configuration example of the vibration element, and FIG. 15 is a cross-sectional view illustrating a method for manufacturing the vibration element illustrated in FIG.
Hereinafter, the manufacturing method of the resonator element according to the fifth embodiment will be described focusing on the differences from the first embodiment described above, and description of similar matters will be omitted.
The fifth embodiment of the present invention is the same as the first embodiment described above except that the configuration of the vibration element to be manufactured and the recessed portion forming step are different. In addition, the same code | symbol is attached | subjected to the structure similar to 1st Embodiment mentioned above.

  As shown in FIG. 14, in the vibration element 1 </ b> D of the present embodiment, the vibration portion 21 is formed by forming recesses on both main surfaces of the piezoelectric substrate 2. In other words, the surface of the thick portion 22 (the main surface on the + Y′-axis direction side) is provided so as to protrude to the + Y′-axis direction side from the surface of the vibration portion 21 (the main surface on the + Y′-axis direction side). The back surface (the main surface on the −Y′-axis direction side) of the thick wall portion 22 is provided so as to protrude to the −Y′-axis direction side from the back surface (the main surface on the −Y′-axis direction side) of the vibration unit 21. Yes. In this manner, by forming the recessed portions on both main surfaces of the piezoelectric substrate 2 to form the vibrating portion 21, for example, the etching depth of the recessed portions can be made shallower than in the first embodiment described above. Can do.

The manufacturing method of the vibration element 1D is the same as the manufacturing method of the first embodiment described above, except for the step of forming the recessed portion. Therefore, hereinafter, only the recess forming step will be described.
As shown in FIG. 15A, a mask M that is a laminate of a chromium layer and a gold layer is formed on both the main surfaces 201 and 202 of the piezoelectric substrate 20 by sputtering or the like. Next, a resist film R having a plurality of openings R1 corresponding to the recessed portions 203 is formed on the mask M by using a photolithography technique and an etching technique. Next, the portion of the mask M exposed from the opening R1 is removed with aqua regia or the like to form a mask M having a plurality of openings M1 corresponding to each region T3, as shown in FIG.

  Next, as shown in FIG. 15C, the piezoelectric substrate 20 is wet-etched (half-etched) through the opening M1 of the mask M using an etching solution (for example, a mixed solution of hydrofluoric acid and ammonium fluoride). And a plurality of recesses 203 are formed on the main surface 201 of the piezoelectric substrate 20, and a plurality of recesses 203 ′ opposite to the recesses 203 are formed on the main surface 202. Thereby, the some thin part 204 is formed so that it may be pinched | interposed into the recessed parts 203 and 203. FIG.

In this way, by forming the recessed portions 203 and 203 ′ on both the main surfaces 201 and 202 of the piezoelectric substrate 20, compared with the manufacturing method of the first embodiment described above, the recessed portions 203 and 203 ′ are further formed. The depth d can be reduced. Therefore, according to the manufacturing method of the present embodiment, it is possible to more effectively manufacture the vibration element 1 in which the thickness t of the vibration part 21 is equal to each other and the thickness t is a desired thickness.
According to the fifth embodiment, the same effect as that of the first embodiment described above can be exhibited.

2. Next, a vibrator to which the above-described vibration element is applied will be described.
FIG. 16 is a cross-sectional view illustrating a configuration example of a vibrator.
A vibrator 10 illustrated in FIG. 16 includes the above-described vibration element 1 and a package 4 that houses the vibration element 1.

(package)
The package 4 includes a box-shaped base 41 having a concave portion 411 that opens to the upper surface, and a plate-shaped lid 42 that closes the opening of the concave portion 411 and is joined to the base 41. The vibration element 1 is stored in the storage space S formed by closing the recess 411 with the lid 42. The storage space S may be in a reduced pressure (vacuum) state or may be filled with an inert gas such as nitrogen, helium, or argon.

  The constituent material of the base 41 is not particularly limited, but various ceramics such as aluminum oxide can be used. The constituent material of the lid 42 is not particularly limited, but may be a member whose linear expansion coefficient approximates that of the constituent material of the base 41. For example, when the constituent material of the base 41 is ceramic as described above, an alloy such as Kovar is preferable. In addition, joining of the base 41 and the lid 42 is not specifically limited, For example, you may join via an adhesive agent and may join by seam welding etc.

Connection electrodes 451 and 461 are formed on the bottom surface of the recess 411 of the base 41. External mounting terminals 452 and 462 are formed on the lower surface of the base 41. The connection electrode 451 is electrically connected to the external mounting terminal 452 through a through electrode (not shown) formed in the base 41, and the connection electrode 461 is externally connected through a through electrode (not shown) formed in the base 41. The mounting terminal 462 is electrically connected.
The configurations of the connection electrodes 451 and 461 and the external mounting terminals 452 and 462 are not particularly limited as long as they have electrical conductivity. For example, a metallized layer such as Cr (chrome) or W (tungsten) (lower It can be constituted by a metal film in which each film such as Ni (nickel), Au (gold), Ag (silver), Cu (copper), etc. is laminated on the (layer).

The vibration element 1 housed in the housing space S is fixed to the base 41 by the conductive adhesive 51 in the mount portion 29 with the surface facing the base 41 side. The conductive adhesive 51 is provided in contact with the connection electrode 451 and the pad electrode 33. Thereby, the connection electrode 451 and the pad electrode 33 are electrically connected via the conductive adhesive 51. By supporting the vibration element 1 at one place (one point) using the conductive adhesive 51, for example, stress generated in the vibration element 1 due to a difference in thermal expansion coefficient between the base 41 and the piezoelectric substrate 2 can be suppressed. .
The conductive adhesive 51 is not particularly limited as long as it has conductivity and adhesiveness. For example, a conductive filler is added to an adhesive such as silicone, epoxy, acrylic, polyimide, or bismaleimide. A dispersed product can be used.

  The pad electrode 34 of the vibration element 1 is electrically connected to the connection electrode 461 through the bonding wire 52. As described above, since the pad electrode 34 is disposed to face the pad electrode 33, the pad electrode 34 is located immediately above the conductive adhesive 51 in a state where the vibration element 1 is fixed to the base 41. Therefore, leakage of vibration (ultrasonic vibration) applied to the pad electrode 34 during wire bonding can be suppressed, and the bonding wire 52 can be more reliably connected to the pad electrode 34.

3. Oscillator Next, an oscillator to which the vibration element is applied will be described.
FIG. 17 is a cross-sectional view illustrating a configuration example of an oscillator.
An oscillator 100 illustrated in FIG. 17 includes a vibrator 10 and an IC chip 110 for driving the vibration element 1. Hereinafter, the oscillator 100 will be described with a focus on differences from the above-described vibrator, and description of similar matters will be omitted.

  As shown in FIG. 17, in the oscillator 100, the IC chip 110 is fixed to the recess 411 of the base 41. The IC chip 110 is electrically connected to a plurality of internal terminals 120 formed on the bottom surface of the recess 411. The plurality of internal terminals 120 include those connected to the connection electrodes 451 and 461 and those connected to the external mounting terminals 452 and 462. The IC chip 110 has an oscillation circuit for controlling the driving of the vibration element 1. When the vibration element 1 is driven by the IC chip 110, a signal having a predetermined frequency can be extracted.

4). Next, an electronic device to which the vibration element is applied will be described.
FIG. 18 is a perspective view illustrating a configuration of a mobile (or notebook) personal computer. 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 10 (vibrating element 1) that functions as a filter, a resonator, a reference clock, and the like.

  FIG. 19 is a perspective view showing a configuration of a mobile phone (including PHS). 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 10 (vibrating element 1) that functions as a filter, a resonator, or the like.

  FIG. 20 is a perspective view showing the configuration of the digital still camera. 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 is provided on the back of a case (body) 1302 in the digital still camera 1300, and is configured to perform display based on an imaging signal from the CCD. The display unit is a finder that displays an object as an electronic image. Function. 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 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 10 (vibrating element 1) that functions as a filter, a resonator, or the like.

  In addition to the personal computer (mobile personal computer) in FIG. 18, the mobile phone in FIG. 19, and the digital still camera in FIG. 20, the electronic device including the vibration element is, for example, an ink jet type ejection device (for example, an ink jet printer). , Laptop personal computers, TVs, video cameras, video tape recorders, car navigation devices, pagers, electronic notebooks (including those with communication functions), electronic dictionaries, calculators, electronic game devices, word processors, workstations, videophones, crime prevention TV monitors, electronic binoculars, POS terminals, medical devices (eg, electronic thermometers, blood pressure monitors, blood glucose meters, electrocardiogram measuring devices, ultrasonic diagnostic devices, electronic endoscopes), fish detectors, various measuring devices, instruments (eg, Of vehicles, aircraft, ships Vessels acids), it can be applied to a flight simulator or the like.

5. Next, a moving body to which the vibration element is applied will be described.
FIG. 21 is a perspective view showing an automobile as an example of a moving object. The automobile 1500 is equipped with the vibrator 10 (the vibration element 1). The vibrator 10 includes a keyless entry, an immobilizer, a car navigation system, a car air conditioner, an anti-lock brake system (ABS), an air bag, a tire pressure monitoring system (TPMS), an engine control, a hybrid vehicle, The present invention can be widely applied to electronic control units (ECUs) such as battery monitors for electric vehicles, vehicle body posture control systems, and the like.

  As mentioned above, although the manufacturing method of the vibration element of this invention was demonstrated based on illustration embodiment, this invention is not limited to this, The structure of each part is arbitrary structures which have the same function. Can be substituted. In addition, any other component may be added to the present invention. Moreover, you may combine each embodiment mentioned above suitably.

  DESCRIPTION OF SYMBOLS 1, 1A, 1B, 1C, 1D ... Vibration element 10 ... Vibrator 100 ... Oscillator 110 ... IC chip 120 ... Internal terminal 2 ... Piezoelectric substrate 20 ... Piezoelectric substrate 201, 202 ... Main surface 203, 203 '... Recessed part 204 ... Thin part 21 ... Vibrating part 211 ... First outer edge 212 ... Second outer edge 213 ... Third outer edge 214 ... Fourth outer edge 219 ... Vibration area 22 ... Thick part 23 ... First thick part 231 ... Inclined part 232 ... Thick wall Main part 24 ... Second thick part 241 ... Inclined part 242 ... Thick part main body 25 ... Third thick part 251 ... Inclined part 252 ... Thick part main body 26 ... Fourth thick part 261 ... Inclined part 262 ... Thick Meat part body 29 ... Mount part 3 ... Electrode 30 ... Metal film 31, 32 ... Excitation electrode 311,312,321,322 ... End 33,34 ... Pad electrode 35,36 ... Lead electrode 4 ... Packet G 41 ... Base 411 ... Recess 42 ... Lid 451, 461 ... Connection electrode 452, 462 ... External mounting terminal 51 ... Conductive adhesive 52 ... Bonding wire 61 ... Adhesive 62 ... Object 900 ... Plasma treatment apparatus 911 ... Upper electrode 912 ... Lower electrode 920 ... Process gas supply means 921 ... Nozzle 930 ... High frequency power source 940 ... NC stage 950 ... Moving device 960 ... Control means 1100 ... Personal computer 1102 ... Keyboard 1104 ... Main body 1106 ... Display unit 1200 ... Mobile phone 1202 ... Operation button 1204 ... Earpiece 1206 ... Mouthpiece 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 2000 ... Display part d ... Depth M, M '... Mask M1, M1' ... Opening R, R '... Resist film R1, R1' ... Opening S ... Storage space t ... Thickness T1 ... Plasma generation region T3 ... Region

Claims (9)

Etching at least one main surface of the substrate ;
The first concave portion is formed on the one main surface to form a first thin portion thinner than the substrate, and the second concave portion is formed on the one main surface to form the substrate. A thin part forming step of forming a second thin part having a smaller thickness than ,
Placing the substrate between the upper and lower electrodes;
Supplying a processing gas between the upper electrode and the lower electrode and applying a voltage to generate plasma,
The surface of the first thin portion is locally moved so that the thickness of the first thin portion is within a predetermined range by relatively moving the region where the plasma is generated and the substrate. Plasma treatment,
The surface of the second thin portion is locally moved so that the thickness of the second thin portion is within the predetermined range by relatively moving the region where the plasma is generated and the substrate. And a thickness adjusting step for plasma processing . After the previous KiAtsu adjusting step,
A thick part thicker than the first thin part is located along at least a part of the outer edge of the first recessed part, and the thick part is located along at least a part of the outer edge of the second recessed part. 2. The method for manufacturing a vibration element according to claim 1, further comprising an individualizing step of dividing the substrate into pieces so that a thick portion thicker than the second thin portion is located . 3. The method for manufacturing a vibration element according to claim 1, wherein the thin-walled portion forming step forms both the first recessed portion and the second recessed portion by etching both main surfaces of the substrate.   The method for manufacturing a vibration element according to claim 1, wherein the etching is wet etching. 2. The thickness adjusting step performs plasma treatment on surfaces of the first thin portion and the second thin portion so that resonance characteristics of the first thin portion and the second thin portion are stabilized. The manufacturing method of the vibration element of any one of thru | or 4. The process gas, the manufacturing method of the vibration device according to at least one of a fluorine atom-containing compound gas and chlorine atom-containing compound gas in any one of including請 Motomeko 1-5. The method for manufacturing a vibration element according to claim 1, further comprising a step of forming electrodes on the first thin portion and the second thin portion after the thickness adjusting step. A first distance in the thickness direction of the substrate between the one main surface and the surface of the first thin portion on the one main surface side, and the one main surface and the one main surface side The manufacturing method of the vibration element according to claim 1 , wherein the second distance in the thickness direction between the second thin-walled portion and the surface of the second thin-walled portion is 30 μm or more and 200 μm or less , respectively. Method. The method for manufacturing a vibration element according to claim 8, wherein the first distance and the second distance are 50 μm or more and 100 μm or less, respectively .

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