Vibrator and method for manufacturing vibrator

Abstract

To provide a vibrator capable of suppressing the occurrence of failure of a vibration element due to frequency adjustment.SOLUTION: The resonator 1 includes the resonator device 3, which includes the resonator element 30, the excitation electrodes 31, which are provided on the 30a of the upper surface of the resonator element 30, the excitation electrodes 32, which are provided on the 30a of the upper surface of the resonator element 30 on the side opposite the 30b of the upper surface of the resonator element 30 and have a recessed 32r, the extension electrodes 41, which are electrically connected to the excitation electrodes 31, and the extension electrodes 42, which are electrically connected to the excitation electrodes 32 and are thicker than the excitation electrodes 32.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a vibrator and a method for manufacturing a vibrator. [Background technology]

[0002] A known method for adjusting the frequency of a quartz crystal vibration element is described in Patent Document 1. In the method described in Patent Document 1, a negative potential is applied to the surface electrode of the quartz crystal vibration element to generate plasma around the surface electrode, ionize argon gas, and etch the surface electrode with the ionized argon gas, thereby adjusting the frequency of the quartz crystal vibration element. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2001-185971 Summary of the Invention [Problem to be solved by the invention]

[0004] As a result of adjusting the frequency of the vibration element of the present invention, the inventors of the present invention found that there was a risk of malfunction occurring in the vibration element of the present invention. For example, there was a risk that the extraction electrode of the vibration element of the present invention would be damaged by ionized argon gas. [Means for solving the problem]

[0005] A vibrator according to one embodiment of the present application comprises a vibrating element having a piezoelectric substrate, a first electrode provided on a first surface of the piezoelectric substrate, a second electrode provided on a second surface opposite the first surface of the piezoelectric substrate and having a thin film portion, a first extraction electrode electrically connected to the first electrode, and a second extraction electrode electrically connected to the second electrode and thicker than the second electrode.

[0006] A method for manufacturing a vibrator according to one embodiment of the present application is a method for manufacturing a vibrator including a vibrating element having a piezoelectric substrate, a first electrode provided on a first surface of the piezoelectric substrate, a second electrode having a thin film portion provided on a second surface of the piezoelectric substrate opposite the first surface, a first extraction electrode electrically connected to the first electrode, and a second extraction electrode electrically connected to the second electrode, the method including the steps of: forming the second extraction electrode to be thicker than the second electrode; and adjusting the frequency of the vibrating element by applying a predetermined potential to the second electrode and etching the surface of the second electrode with ions. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a perspective view of a vibrator according to a first embodiment. [Figure 2] Cross-sectional view of the vibrator taken along line AA in Figure 1. [Figure 3] FIG. [Figure 4] FIG. 4 is a perspective view of the vibration element of FIG. 3 as viewed from the back side. [Figure 5] FIG. 4 is a cross-sectional view of the vibration element taken along line BB in FIG. 3 . [Figure 6] 10 is a flowchart showing a manufacturing process of a vibrator. [Figure 7] 7 is a flowchart showing details of the vibration element preparation step in FIG. 6. [Figure 8] 8 is a flowchart showing details of the electrode formation step in FIG. 7. [Figure 9] 8 is a flowchart showing details of the frequency adjustment step in FIG. 7; [Figure 10] 1A to 1C are cross-sectional views showing one embodiment of a manufacturing process. [Figure 11] 1A to 1C are cross-sectional views showing one embodiment of a manufacturing process. [Figure 12] 1A to 1C are cross-sectional views showing one embodiment of a manufacturing process. [Figure 13] FIG. 1 is a conceptual diagram showing an overview of a frequency adjustment device. [Figure 14A] 1A to 1C are cross-sectional views showing one embodiment of a manufacturing process. [Figure 14B] FIG. 10 is a cross-sectional view showing another embodiment in the manufacturing process. [Figure 15] FIG. 10 is a perspective view of a vibration element according to a second embodiment. [Figure 16] FIG. 16 is a perspective view of the vibration element of FIG. 15 as viewed from the back side. [Figure 17] FIG. 16 is a cross-sectional view of the vibration element taken along line CC in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0008] In the embodiments of the present invention, components shown in the drawings may be shown with different scales for clarity. In the drawings, three mutually perpendicular axes, the X-axis, Y-axis, and Z-axis, may be illustrated. In the following explanation, the tip end of the arrows on the three axes may be referred to as the "plus side," and the base end of the arrow may be referred to as the "minus side." The direction parallel to the X-axis may be referred to as the "X-axis direction," the direction parallel to the Y-axis may be referred to as the "Y-axis direction," and the direction parallel to the Z-axis may be referred to as the "Z-axis direction."

[0009] The term "top surface" of a certain structure refers to the surface on the positive side of the Z axis direction of the structure, for example, "top surface of a substrate" refers to the surface on the positive side of the Z axis direction of a movable body. The term "bottom surface" of a certain structure refers to the surface on the negative side of the Z axis direction of the structure, for example, "bottom surface of the substrate" refers to the surface on the negative side of the Z axis direction of the movable body. Reference to a surface of a structure is intended to refer to the outer surface of the structure.

[0010] 1. Embodiment 1 1.1. Oscillator configuration Fig. 1 is a perspective view of a vibrator 1 according to this embodiment, and Fig. 2 is a cross-sectional view of the vibrator 1 taken along line AA in Fig. 1.

[0011] The resonator 1 shown in Fig. 1 is an oscillator, and more specifically, a crystal oscillator in which a resonator element 3 made of quartz crystal and an oscillation circuit 7 are packaged together. The resonator 1 is mounted on a circuit board 100 of electronic devices such as quartz watches, communication devices, computers, display devices, printing devices, industrial robots, automobiles, and aircraft, and is used for timing control, frequency control, etc. of the electronic devices.

[0012] The vibrator 1 has a base 10 , a cover 20 , and a vibrating element 3 . The base 10 includes a substrate 11 and an oscillator circuit 7 . The substrate 11 is a silicon substrate. The substrate 11 may be made of a semiconductor material other than silicon, such as Ge, GaP, GaAs, or InP. An oscillator circuit 7 is provided on the upper surface of the substrate 11. The oscillator circuit 7 is a semiconductor circuit including an element 700, a wiring layer 14, a terminal layer 17, insulating layers 13 and 15, and a passivation layer 16. The oscillator circuit 7 is electrically connected to the vibration element 3 via a bonding member B, and is also electrically connected to an external terminal 18 via a through electrode 18v. An insulating layer 12 is provided between the external terminals 18 and the substrate 11 and between the through electrodes 18v and the substrate 11.

[0013] In this embodiment, the oscillator circuit 7 is provided on the vibration element 3 side of the substrate 11, but the oscillator circuit 7 may also be provided on the circuit board 100 side of the substrate 11. The oscillator circuit 7 may also be in the form of a semiconductor chip. In this case, the semiconductor chip on which the oscillator circuit 7 is mounted may be mounted inside or outside the vibrator 1, or may be mounted on the circuit board 100 and electrically connected to the vibrator 1. In other words, in this embodiment, the vibrator 1 may be configured without the oscillator circuit 7, in other words, may be configured such that only the vibration element 3 is housed in a package.

[0014] The lid 20 has a recess 20r. The lid 20 is joined to the outer periphery of the upper surface of the base 10 via a joining portion 60, and a storage space S is formed between the lid 20 and the base 10. The vibration element 3 is accommodated in the accommodation space S. The accommodation space S is airtight and in a reduced pressure state, preferably a state closer to a vacuum. This reduces viscous resistance and improves the oscillation characteristics of the vibration element 3. However, the atmosphere in the accommodation space S is not particularly limited.

[0015] 1.2. Vibration element configuration Fig. 3 is a perspective view of the vibration element 3 according to this embodiment. Fig. 4 is a perspective view of the vibration element 3 of Fig. 3 as seen from the back side. Fig. 5 is a cross-sectional view of the vibration element 3 taken along line BB of Fig. 3.

[0016] The vibration element 3 has a vibration element 30, excitation electrodes 31 and 32, and extraction electrodes 41 and . In this embodiment, an AT-cut quartz crystal vibrating piece that vibrates in a thickness-shear vibration mode is used as a suitable example of the vibrating piece 30. The AT-cut quartz crystal vibrating piece has a third-order frequency-temperature characteristic, and therefore can form a vibrating element 3 with excellent temperature characteristics.

[0017] The excitation electrode 31 is arranged on the surface 30a of the vibrating bar 30. The excitation electrode 32 is arranged on the surface 30b of the vibrating bar 30. The surface 30a is the upper surface of the vibrating bar 30, and the surface 30b is the lower surface of the vibrating bar 30. In this embodiment, the vibrating bar 30 is an example of a piezoelectric substrate. The surface 30a is an example of a first surface, and the surface 30b is an example of a second surface. The excitation electrode 31 is an example of a first electrode, and the excitation electrode 32 is an example of a second electrode.

[0018] The excitation electrodes 31 and 32 are each a laminated film, and include a metal film 51 and a metal film 52. The lower metal film 51 is preferably a chromium (Cr) film or a nickel (Ni) film. The upper metal film 52 is preferably a gold (Au) film or a silver (Ag) film. The upper metal film 52 is a surface layer of the excitation electrodes 31 and 32, and functions as a frequency adjustment film for adjusting the resonance frequency of the vibration element 3 in a frequency adjustment step S23 described later.

[0019] The vibration element 3 may be configured as a mesa type in which the vibration region sandwiched between the excitation electrodes 31 and 32 protrudes from its surroundings, or conversely, as an inverted mesa type in which the vibration region is recessed from its surroundings. In addition, the vibration element 3 may be subjected to bevel processing in which the periphery of the vibration element 30 is ground, or convex processing in which the upper and lower surfaces are made convex.

[0020] The vibration element 3 is not limited to vibrating in a thickness-shear vibration mode. For example, it may be a vibration element in which multiple vibrating arms vibrate in an in-plane direction. That is, the vibration element 30 is not limited to being formed from an AT-cut quartz crystal vibrating element, but may be formed from a quartz crystal vibrating element other than an AT-cut quartz crystal vibrating element, such as an X-cut quartz crystal vibrating element, a Y-cut quartz crystal vibrating element, a Z-cut quartz crystal vibrating element, a BT-cut quartz crystal vibrating element, an SC-cut quartz crystal vibrating element, or an ST-cut quartz crystal vibrating element. In the present embodiment, the vibration element 30 is made of quartz crystal, but is not limited thereto. For example, the vibration element 30 may be made of a piezoelectric single crystal such as lithium niobate, lithium tantalate, lithium tetraborate, langasite, potassium niobate, or gallium phosphate, or may be made of other piezoelectric single crystals. Furthermore, the vibration element 3 is not limited to a piezoelectrically driven vibration element, but may also be an electrostatically driven vibration element using electrostatic force.

[0021] The extraction electrode 41 is provided on the surface 30a of the vibrating bar 30, and electrically connects the excitation electrode 31 and the bonding member B. The extraction electrode 42 is provided on the surface 30b of the vibrating bar 30, and electrically connects the excitation electrode 32 and the bonding member B. In this embodiment, the extraction electrode 41 is an example of a first extraction electrode, and the extraction electrode 42 is an example of a second extraction electrode.

[0022] The extraction electrode 41 includes a terminal portion 41a and a connection portion 41b. The terminal portion 41a is provided on the surface 30b of the vibrating element 30 and is electrically connected to the bonding member B. The connection portion 41b is provided on the surface 30a, the side surface 30c, and the surface 30b of the vibrating element 30 and electrically connects the terminal portion 41a and the excitation electrode 31.

[0023] The extraction electrode 42 includes a terminal portion 42a and a connection portion 42b. The terminal portion 42a is provided on the surface 30b of the vibrating element 30 and is electrically connected to the bonding member B. The connection portion 42b is provided on the surface 30b of the vibrating element 30 and electrically connects the terminal portion 42a and the excitation electrode 32.

[0024] The extraction electrode 41 and the extraction electrode 42 are each a three-layer laminate film including a metal film 51, a metal film 52, and a metal film 53. The lowermost metal film 51 is the same layer as the metal film 51 below the excitation electrodes 31 and 32, and is formed using the same process and material. The metal film 52 in the middle layer is the same layer as the metal film 52 on the upper side of the excitation electrodes 31 and 32, and is formed in the same process and with the same material.

[0025] The uppermost metal film 53 is preferably formed of the same material as the metal film 52. For example, if the metal film 52 is a gold film, the metal film 53 is also a gold film. The uppermost metal film 53 is the surface layer of the extraction electrodes 41 and 42.

[0026] The excitation electrode 31 has a thickness t1. The extraction electrode 41 has a thickness t2. More specifically, the terminal portion 41a and the connection portion 41b of the extraction electrode 41 each have a thickness t2. The thickness t2 of the extraction electrode 41 is thicker than the thickness t1 of the excitation electrode 31. In this embodiment, the thickness t2 is about 1.5 times the thickness t1, but is not limited to this, and the thickness t2 may be about 2 to 3 times the thickness t1. For example, when the thickness t2 is about twice the thickness t1, the metal film 53 may be formed so that its film thickness becomes the thickness t1.

[0027] The excitation electrode 32 has a thickness t3. The extraction electrode 42 has a thickness t4. More specifically, the terminal portion 42a and the connection portion 42b of the extraction electrode 42 each have a thickness t4. The thickness t4 of the extraction electrode 42 is thicker than the thickness t3 of the excitation electrode 32. In this embodiment, the thickness t4 is about 1.5 times the thickness t3, but is not limited to this, and the thickness t3 may be about 2 to 3 times the thickness t4. For example, when the thickness t4 is about twice the thickness t3, the metal film 53 may be formed so that its film thickness is equal to the thickness t3.

[0028] The thickness t1 and the thickness t3 may be the same or different. The thickness t2 and the thickness t4 may be the same or different. For example, in the frequency adjustment step S23, if the electric field is different between the upper surface side and the lower surface side of the vibrating element 30, the thicknesses t1 and t3, and the thicknesses t2 and t4 will be different.

[0029] In this embodiment, the main reasons why the thickness t2 of the extraction electrode 41 is made thicker than the thickness t1 of the excitation electrode 31 and the thickness t4 of the extraction electrode 42 is made thicker than the thickness t3 of the excitation electrode 32 are as follows. The first reason is that a DC bias greater than that applied to the excitation electrodes 31 and 32 is applied to the extraction electrodes 41 and 42 in the frequency adjustment step S23.

[0030] In the frequency adjustment step S23, a negative DC voltage is applied to the excitation electrodes 31 and 32. This negative DC voltage is applied to the excitation electrodes 31 and 32 via the extraction electrodes 41 and 42, so that the potentials of the excitation electrodes 31 and 32 are higher than the potentials of the extraction electrodes 41 and 42. In other words, the potentials of the extraction electrodes 41 and 42 are lower than the potentials of the excitation electrodes 31 and 32. That is, the DC bias is higher for the extraction electrodes 41 and 42 than for the excitation electrodes 31 and 32. Therefore, the number of ions colliding with the extraction electrodes 41 and 42 per unit area is greater, and the extraction electrodes 41 and 42 are more likely to be etched than the excitation electrodes 31 and 32.

[0031] 3 and 4, the extraction electrodes 41 and 42 are narrower and have a smaller area than the excitation electrodes 31 and 32. Therefore, the extraction electrodes 41 and 42 are more affected by etching than the excitation electrodes 31 and 32.

[0032] As described above, in this embodiment, the thickness t2 of the extraction electrode 41 is made thicker than the thickness t1 of the excitation electrode 31, and the thickness t4 of the extraction electrode 42 is made thicker than the thickness t3 of the excitation electrode 32, so that even if the extraction electrodes 41 and 42 are etched away in the frequency adjustment step S23, defects such as high resistance and disconnection are avoided in the extraction electrodes 41 and 42. In other words, in the extraction electrodes 41 and 42, the metal film 53 functions as a mask that reduces damage caused by collision with argon ions in the frequency adjustment step S23.

[0033] Furthermore, in the frequency adjustment step S23, the extraction electrodes 41 and 42 are removed by etching, so that the extraction electrodes 41 and 42 also function as frequency adjustment films. However, since the surface areas of the extraction electrodes 41 and 42 are smaller than those of the excitation electrodes 31 and 32, their effect as frequency adjustment films is smaller than that of the excitation electrodes 31 and 32.

[0034] When only the excitation electrode 32 and the extraction electrodes 41, 42 on the surface 30b side of the vibrating bar 30 are used as frequency adjustment films, the film thickness of the extraction electrode 41 arranged on the surface 30a side of the vibrating bar 30 may be thickness t1. In other words, the metal film 53 may be omitted from the extraction electrode 41 arranged on the surface 30a side of the vibrating bar 30. In this case, the surface 30a side of the vibrating bar 30 is treated so as to suppress etching in the frequency adjustment step S23.

[0035] 1.3.Vibrator manufacturing method 6 to 14B are diagrams illustrating a method for manufacturing the vibrator 1 of this embodiment. FIG. 6 is a flowchart showing the manufacturing process of the vibrator 1. FIG. 7 is a flowchart showing details of the vibrating element preparation step S2 in FIG. 6. FIG. 8 is a flowchart showing details of the electrode formation step S22 in FIG. 7. FIG. 9 is a flowchart showing details of the frequency adjustment step S23 in FIG. 7. FIG. 10 is a cross-sectional view showing one embodiment of the first film formation step S221 in FIG. 8. FIG. 11 is a cross-sectional view showing one embodiment of the second film formation step S222 in FIG. 8. FIG. 12 is a cross-sectional view showing one embodiment of the patterning step S223 in FIG. 8. FIG. 13 is a conceptual diagram showing an overview of the frequency adjustment device 8. FIG. 14A is a cross-sectional view showing one embodiment of the etching step S233 in FIG. 9. FIG. 14B is a cross-sectional view showing another embodiment of the etching step S233 in FIG. 9.

[0036] As shown in FIG. 6, the method for manufacturing the vibrator 1 includes a semiconductor substrate preparation step S1, a vibrating element preparation step S2, a mounting step S3, and a sealing step S4.

[0037] In the semiconductor substrate preparation step S1, a base 10 having an oscillation circuit 7 is prepared as shown in FIG. 3, 4, and 5, the vibration element 3 is prepared, which has excitation electrodes 31 and 32 made of metal films 51 and 52, and extraction electrodes 41 and 42 made of metal films 51, 52, and 53. Details of the vibration element preparation step S2 will be described later.

[0038] In the mounting step S3, the vibration element 3 is mounted on the base 10 as shown in FIG. In the sealing step S4, as shown in FIG. 2, the lid 20 is joined to the outer periphery of the upper surface of the base 10 via a joint 60, thereby sealing the vibration element 3 in the accommodation space S.

[0039] 1.4. Vibration element preparation process As shown in FIG. 7, the vibration element preparation step S2 includes a vibration piece preparation step S21, an electrode formation step S22, and a frequency adjustment step S23.

[0040] 1.4.1. Vibration piece preparation process In the vibrator element preparation step S21, the vibrator element 30, which is an AT-cut quartz crystal substrate, is prepared.

[0041] 1.4.2. Electrode formation process In the electrode formation step S22, the excitation electrode 31 and the extraction electrode 41, as well as the excitation electrode 32 and the extraction electrode 42, are formed on the surfaces 30a and 30b of the vibrator element 30 as shown in FIGS.

[0042] As shown in FIG. 8, the electrode forming step S22 includes a first film forming step S221, a second film forming step S222, a patterning step S223, a resist mask forming step S224, a third film forming step S225, and a resist mask removing step S226.

[0043] 10, in the first film formation process S221, a metal film 51 is formed on the entire surface, including the front surface 30a, the front surface 30b, and the side surface 30c, of the vibrating element 30 by a vapor deposition method such as a vacuum deposition method or a sputtering method. In this embodiment, the metal film 51 is a chromium film.

[0044] 11, in the second film formation step S222, a metal film 52 is formed by any of various vapor phase film formation methods such as vacuum deposition and sputtering so as to cover the entire surface of the metal film 51. In this embodiment, the metal film 52 is a gold film.

[0045] In the patterning process S223, as shown in FIG. 12, a laminated film consisting of a chromium film and a gold film is patterned using photolithography and etching to form excitation electrodes 31 and 32, as well as a work electrode for extraction electrode 41 and a work electrode 42z for extraction electrode 42 (not shown).

[0046] Next, a resist mask forming step S224, a third film forming step S225, and a resist mask removing step S226 are performed to form a metal film 53, thereby completing the extraction electrodes 41 and 42. In this embodiment, the metal film 53 is formed using a lift-off method, but other film forming methods such as mask vapor deposition may also be used.

[0047] 1.4.3. Frequency Adjustment Process In the frequency adjusting step S23, the mass of the vibration element 3 is reduced using a frequency adjusting device 8 shown in FIG. 13, thereby adjusting the resonance frequency of the vibration element 3 to a desired value.

[0048] 13, frequency adjustment device 8 includes an adjustment chamber 81, a power supply 82, a frequency measurement device 83, switches 84a and 84b, lead wires 85a and 85b, a gas inlet valve 86a, and a gas outlet valve 86b. The positive terminals of adjustment chamber 81 and power supply 82 are connected to earth.

[0049] As shown in FIG. 9, the frequency adjusting step S23 includes a frequency measuring step S231, a determining step S232, and an etching step S233.

[0050] 1.4.3.1. Frequency measurement process In the frequency measurement step S231, the resonance frequency of the vibration element 3 is measured. In this process, first, the vibration element 3 is placed in the adjustment chamber 81, and the lead wires 85a and 85b are connected to the extraction electrodes 41 and 42, respectively. The switches 84a and 84b are each connected to the frequency measuring device 83. Next, the adjustment chamber 81 is evacuated, and the resonant frequency of the vibration element 3 is measured by the frequency measuring device 83.

[0051] 1.4.3.2.Judgment process In the determination step S232, it is determined whether or not frequency adjustment of the vibration element 3 is necessary based on the frequency measured by the frequency measurement device 83. If the measured frequency is not the desired frequency, the process proceeds to the etching step S233, and if the measured frequency is the desired frequency, the frequency adjustment step S23 is terminated.

[0052] Etching process 14A, in the etching step S233, the surface 32s of the excitation electrode 32, the surface 42s of the extraction electrode 42, and the surface 41s on the negative side in the Z-axis direction of the extraction electrode 41 (not shown) are removed to adjust the resonance frequency of the vibration element 3. In this embodiment, the surface 31s of the excitation electrode 31 provided on the surface 30a of the vibration bar 30 and the surface 41s on the positive side in the Z-axis direction of the extraction electrode 41 are treated so as not to be etched.

[0053] The frequency adjustment in the etching step S233 may be performed using all of the excitation electrodes 31 and 32 and the extraction electrodes 41 and 42, or only the surfaces 41s on the positive side in the Z-axis direction of the excitation electrodes 31 and 41. A configuration in which the frequency adjustment is performed using only the surfaces 41s on the positive side in the Z-axis direction of the excitation electrodes 31 and 41 will be described in the next section.

[0054] 13, in the etching step S233, an inert discharge gas is introduced into the adjustment chamber 81 through the gas introduction valve 86a. In this embodiment, argon gas is introduced into the adjustment chamber 81 as the discharge gas. The switches 84a and 84b are each connected to the power source 82. Note that the switch 84a electrically connected to the excitation electrode 31 may be connected to an open terminal, but since it is preferable that the excitation electrodes 31 and 32 be at the same potential during the etching step S233, in this embodiment the switches 84a and 84b are each connected to the power source 82.

[0055] A negative DC voltage is applied from the power supply 82 to the excitation electrodes 31 and 32 via the lead wires 85a and 85b and the extraction electrodes 41 and 42, respectively. When a negative DC voltage is applied to the excitation electrode 32, the argon gas around the excitation electrode 32 becomes a plasma state. Argon cations 88 in the plasma are accelerated by the negative potential of the excitation electrode 32 and collide with the surface 32s of the excitation electrode 32, etching the excitation electrode 32. The method of generating plasma is not limited to application of a DC voltage; high-frequency discharge plasma may also be generated by applying an AC voltage to the argon gas. In the case of high-frequency discharge plasma, by applying a negative DC voltage to the excitation electrode 32, the argon cations 88 in the plasma can be accelerated by the negative potential of the excitation electrode 32 and collide with the surface 32s of the excitation electrode 32, etching the excitation electrode 32.

[0056] When the argon cations 88 collide with the excitation electrode 32, metal particles 89 fly out from the metal film 52 on the surface side, which is a frequency adjustment film, and the surface 32s of the excitation electrode 32 is gradually eroded. In this embodiment, the metal film 52 on the surface side is a gold film. Therefore, the metal particles 89 are gold particles.

[0057] 14A, recesses 32r and protrusions 32c are formed on the surface 32s of the excitation electrode 32 by etching. The recesses 32r are thinner portions due to more advanced etching than the protrusions 32c. The protrusions 32c are formed in an island shape on the surface 32s of the excitation electrode 32, and the recesses 32r are formed between the multiple protrusions 32c. In this embodiment, the recesses 32r are an example of thin film portions.

[0058] In this embodiment, the excitation electrode 32 has a two-layer structure consisting of a gold film on the surface side and a chromium film on the lower side. Because the ion etching rate of the lower chromium film is smaller than that of the gold film on the surface side, even if the lower chromium film is exposed in the recess 32r, etching of the lower chromium film is suppressed. Therefore, damage such as holes in the excitation electrode 32 is suppressed.

[0059] In this embodiment, the surface 42s of the extraction electrode 42 is removed by etching, and recesses 42r and protrusions 42c are formed on the surface 42s. The recesses 42r and protrusions 42c are mainly formed in the metal film 53. In FIG. 14A, the extraction electrode 42 is thicker than at least a portion of the excitation electrode 32. Therefore, even if the extraction electrode 42 is removed by etching in the frequency adjustment step S23, defects such as high resistance and disconnection of the extraction electrode 42 are avoided. Although not shown, the surface 41s on the negative side in the Z-axis direction of the extraction electrode 41 is also removed by etching, and a recess 41r and a protrusion 41c are formed on the surface 41s. The recess 41r and the protrusion 41c are mainly formed in the metal film 53. The extraction electrode 41 is also thicker than at least a portion of the excitation electrode 32. Therefore, even if the extraction electrode 41 is removed by etching in the frequency adjustment step S23, defects such as high resistance and disconnection of the extraction electrode 41 are avoided.

[0060] After the etching step S233 is completed, the process returns to the frequency measurement step S231 to measure the resonance frequency of the vibration element 3. Then, steps S231, S232, and S233 are repeated until the resonance frequency of the vibration element 3 reaches the desired frequency.

[0061] 1.4.3.4. Another Aspect of the Etching Process 14B is a cross-sectional view showing another example of the etching step S233. In FIG. 14B, the cross section at a position including the extraction electrode 41 is shown.

[0062] 14B, the resonance frequency of the vibration element 3 is adjusted by scraping the surface 31s of the excitation electrode 31 and the surface 41s on the negative side in the Z-axis direction of the extraction electrode 41. In the form shown in FIG. 14B, the vibration element 3 is placed inside the adjustment chamber 81 in a state where it is upside down compared to the form shown in FIG. 14A. In addition, the excitation electrode 32 side is treated so as not to be etched.

[0063] 14B, recesses 31r and protrusions 31c are formed by etching on the surface 31s of the excitation electrode 31. The recesses 31r are thinner than the protrusions 31c due to more advanced etching. The protrusions 31c are formed in island shapes on the surface 31s of the excitation electrode 31, and the recesses 31r are formed between the multiple protrusions 31c.

[0064] In this embodiment, the surface 41s on the negative side in the Z-axis direction of the extraction electrode 41 is removed by etching, and a recess 41r and a protrusion 41c are formed on the surface 41s. The recess 41r and the protrusion 41c are mainly formed in the metal film 53. In FIG. 14B , the extraction electrode 41 is thicker than at least a portion of the excitation electrode 31. Therefore, even if the extraction electrode 41 is removed by etching in the frequency adjustment step S23, defects such as high resistance and disconnection of the extraction electrode 41 are avoided.

[0065] As described above, the vibrator 1 of this embodiment comprises a vibrating element 3 having a vibrating bar 30 as a piezoelectric substrate, an excitation electrode 31 as a first electrode provided on the surface 30a as a first surface of the vibrating bar 30, an excitation electrode 32 as a second electrode provided on the surface 30b as a second surface opposite the surface 30a of the vibrating bar 30 and having a recess 32r as a thin film portion, an extraction electrode 41 as a first extraction electrode electrically connected to the excitation electrode 31, and an extraction electrode 42 as a second extraction electrode electrically connected to the excitation electrode 32 and thicker than the excitation electrode 32.

[0066] As described above, in this embodiment, the extraction electrode 42 is thicker than the excitation electrode 32. Therefore, even if the excitation electrode 32 has a configuration in which the recess 32r is provided, defects such as high resistance and disconnection can be avoided in the extraction electrode 42. Therefore, a vibrator 1 with excellent quality can be realized.

[0067] In the vibrator 1 of this embodiment, the extraction electrode 42 serving as the second extraction electrode has a terminal portion 42a and a connection portion 42b that electrically connects the terminal portion 42a to the excitation electrode 32 serving as the second electrode, and the connection portion 42b is thicker than the excitation electrode 32. A thickness t4 of the connection portion 42b of the extraction electrode 42 is thicker than a thickness t3 of the excitation electrode 32. Furthermore, the recess 42r is provided in the metal film 53, and the recess 32r is provided in the metal film 52. Therefore, even if the excitation electrode 32 has a configuration including the recess 32r, the connection portion 42b of the extraction electrode 42 is prevented from suffering from defects such as high resistance or disconnection.

[0068] The manufacturing method of the vibrator 1 of this embodiment is a manufacturing method of the vibrator 1 including a vibrating element 3 having a vibrating bar 30 as a piezoelectric substrate, an excitation electrode 31 as a first electrode provided on a surface 30a as a first surface of the vibrating bar 30, an excitation electrode 32 as a second electrode provided on a surface 30b as a second surface opposite to the surface 30a of the vibrating bar 30, a lead electrode 41 as a first lead electrode electrically connected to the excitation electrode 31, and a lead electrode 42 as a second lead electrode electrically connected to the excitation electrode 32, and includes an electrode forming process S22 as a process of forming the lead electrode 42 thicker than the excitation electrode 32, and a frequency adjustment process S23 as a process of adjusting the frequency of the vibrating element 3 by applying a predetermined potential to the excitation electrode 32 and scraping the surface 32s of the excitation electrode 32 with ions.

[0069] As described above, this embodiment includes the electrode forming step S22 in which the extraction electrode 42 is formed to be thicker than the excitation electrode 32. Therefore, even if the surface 42s of the extraction electrode 42 is scraped in the frequency adjusting step S23, defects such as high resistance and disconnection of the extraction electrode 42 are avoided. Therefore, a resonator 1 with excellent quality can be realized.

[0070] 2. Embodiment 2 Fig. 15 is a perspective view of the vibration element 3a according to embodiment 2. Fig. 16 is a perspective view of the vibration element 3a of Fig. 15 as seen from the back side. Fig. 17 is a cross-sectional view of the vibration element 3a taken along line CC of Fig. 15.

[0071] In the second embodiment, another form of the vibration element 3 used in the vibrator 1 of the first embodiment is shown. The vibration element 3a of the second embodiment differs from the vibration element 3 shown in the first embodiment in that the excitation electrode 31 has thick portions 311, 312, 313, and 314 at the four corners thereof, respectively, and the excitation electrode 32 has thick portions 321, 322, 323, and 324 at the four corners thereof, respectively. In the following description, the same components as those of the first embodiment are denoted by the same reference numerals, and redundant description will be omitted.

[0072] 17, the thick portions 311, 312, 313, and 314 of the excitation electrode 31 are made of a three-layer laminate of metal films 51, 52, and 53, each having a thickness t2. On the other hand, the central portion 31e of the excitation electrode 31, excluding the thick portions 311, 312, 313, and 314, is made of a two-layer laminate of metal films 51 and 52, each having a thickness t1. Although the thick portions 311 and 314 are not shown in FIG. 17, the thick portions 311 and 314 are configured similarly to the thick portions 312 and 313.

[0073] The thick portions 321, 322, 323, and 324 of the excitation electrode 32 are made of a three-layer laminate of metal films 51, 52, and 53, each having a thickness t4. On the other hand, the central portion 31e of the excitation electrode 32, excluding the thick portions 321, 322, 323, and 324, is made of a two-layer laminate of metal films 51 and 52, each having a thickness t3. Although the thick portions 321 and 324 are not shown in FIG. 17, the thick portions 321 and 324 are configured similarly to the thick portions 322 and 323.

[0074] In this embodiment, the thick portions 311, 312, 313, and 314 of the excitation electrode 31 and / or the thick portions 321, 322, 323, and 324 of the excitation electrode 32 are each an example of a thick film portion.

[0075] 15 and 16, in the second embodiment, thick portions 311, 312, 313, and 314 and thick portions 321, 322, 323, and 324 are provided at the four corners of the excitation electrode 31 and the excitation electrode 32, respectively, for the following reasons.

[0076] Through experiments conducted by the inventors, it has been found that etching of the four corners of the excitation electrodes 31 and 32 progresses more rapidly than etching of the central portions 31e and 32e of the excitation electrodes 31 and 32 in the frequency adjustment step S23.

[0077] Based on this finding, in the second embodiment, thick portions 311, 312, 313, and 314 are provided at the four corners of the surface 31s of the excitation electrode 31, and thick portions 321, 322, 323, and 324 are provided at the four corners of the surface 32s of the excitation electrode 32, respectively, thereby preventing etching at the four corners of the excitation electrode 31 and the four corners of the excitation electrode 32 from progressing more than at the central portions 31e and 32e. Therefore, the configuration of the second embodiment prevents defects such as high resistance or chipping at the four corners of the excitation electrode 31 and the four corners of the excitation electrode 32. Furthermore, the frequency adjustment range of the vibration element 3 can be increased, and the adjustment time can be lengthened.

[0078] In the second embodiment, when the resonance frequency of the vibration element 3 is adjusted by cutting the surface 31s of the excitation electrode 31, the thick portions 321, 322, 323, and 324 of the excitation electrode 32 may be omitted. On the other hand, when the resonance frequency of the vibration element 3 is adjusted by cutting the surface 32s of the excitation electrode 32, the thick portions 311, 312, 313, and 314 of the excitation electrode 31 may be omitted.

[0079] As described above, in the vibrator 1 of the second embodiment, the excitation electrode 32 has the thick portions 321, 322, 323, and 324 as thick film portions at the four corners.

[0080] As described above, according to the second embodiment, it is possible to prevent defects such as high resistance or loss at the four corners of the excitation electrode 32. Furthermore, it is possible to increase the adjustment range of the frequency of the vibration element 3 and lengthen the adjustment time.

[0081] Although the preferred embodiment has been described above, the present invention is not limited to the above embodiment. The configuration of each part of the present invention can be replaced with any configuration that exhibits the same function as the above embodiment. [Explanation of symbols]

[0082] 1... vibrator, 3... vibrating element, 3a... vibrating element, 7... oscillation circuit, 8... frequency adjustment device, 10... base, 11... substrate, 12, 13... insulating layer, 14... wiring layer, 15... insulating layer, 16... passivation layer, 17... terminal layer, 18... external terminal, 18v... through electrode, 20... lid, 20r... recess, 30... vibrating element, 30a, 30b... surface, 30c... side, 31... excitation electrode, 31c... convex portion, 31r... recess, 31s... surface, 31e... central portion, 32... excitation electrode, 32c... convex portion, 32r... recess, 32s... surface, 32e... central portion, 41... extraction electrode, 41a... terminal portion, 41b... connection portion, 41c... convex portion, 41r ...recess, 41s...surface, 42...extraction electrode, 42a...terminal portion, 42b...connection portion, 42c...protrusion portion, 42r...recess, 42s...surface, 42z...working electrode, 51, 52, 53...metal film, 60...joint portion, 81...adjustment chamber, 82...power supply, 83...frequency measuring device, 84a, 84b...switch, 85a, 85b...lead wire, 86a...gas inlet valve, 86b...gas outlet valve, 88...argon cation, 89...metal particle, 100...circuit board, 311, 312, 313, 314...thick portion, 321, 322, 323, 324...thick portion, 700...element, S...accommodation space, B...jointing member, t1, t2, t3, t4...thickness.

Claims

1. a piezoelectric substrate; a first electrode provided on a first surface of the piezoelectric substrate; a second electrode provided on a second surface of the piezoelectric substrate opposite to the first surface, the second electrode having a thin film portion; a first extraction electrode electrically connected to the first electrode; a second extraction electrode electrically connected to the second electrode and thicker than the second electrode; Vibrator.

2. the second extraction electrode has a terminal portion and a connection portion that electrically connects the terminal portion and the second electrode, the connection portion is thicker than the second electrode; The vibrator according to claim 1 .

3. the second electrode has thick film portions at four corners; The vibrator according to claim 1 .

4. A method for manufacturing a vibrator including a vibrating element having a piezoelectric substrate, a first electrode provided on a first surface of the piezoelectric substrate, a second electrode provided on a second surface of the piezoelectric substrate opposite to the first surface and having a thin film portion, a first extraction electrode electrically connected to the first electrode, and a second extraction electrode electrically connected to the second electrode, forming the second extraction electrode to be thicker than the second electrode; applying a predetermined potential to the second electrode to shave the surface of the second electrode with ions, thereby adjusting the frequency of the vibration element. A method for manufacturing a vibrator.

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