Tuning fork type crystal oscillator, crystal device, and intermediate wafer

Abstract

The invention provides a tuning fork type crystal oscillator, a crystal device, and an intermediate wafer. The tuning-fork-type crystal oscillator has a novel structure in which the electrodes in the support arms of the tuning-fork-type crystal oscillator having a three-arm structure can be reliably divided compared with conventional tuning-fork-type crystal oscillators. A tuning fork type crystal oscillator (10) is provided with: a base part (11); a first vibrating arm (13a) and a second vibrating arm (13b); a support arm (15); a first excitation electrode (17a) and a second excitation electrode (17b); and a first connection pad (17ax) provided on the tip side of the support arm, and a second connection pad (17bx) provided on the base side of the support arm, the first connection pad (17ax) and the second connection pad (17bx) connecting the excitation electrode to the outside. Furthermore, a first cutout (15a) parallel to a first X-axis (X1) of the crystal and a second cutout (15b) parallel to a second X-axis (X2) caused by the crystal being a trigonal system are included in a region between the first connection pad and the second connection pad of the support arm.

Description

Technical Field

[0001] The present invention relates to a tuning fork type crystal oscillator with a three-arm structure, a crystal device using the tuning fork type crystal oscillator, and an intermediate wafer for manufacturing the tuning fork type crystal oscillator. Background Art

[0002] As a tuning fork type crystal oscillator that is advantageous for miniaturization, there is a so-called three-arm structure tuning fork type crystal oscillator. One example is disclosed in Patent Document 1. The tuning fork type crystal oscillator includes: a base, a first vibration arm and a second vibration arm extending in parallel from the base in the same direction, and a support arm extending in parallel from the base in the same direction as the vibration arm between the vibration arms.

[0003] Two excitation electrodes with different polarities are provided in a predetermined arrangement on the first vibration arm and the second vibration arm. Lead electrodes are led out from the excitation electrodes to the support arms, respectively. The ends of the lead electrodes serve as first and second connection pads for fixing the tuning fork type crystal oscillator to the container.

[0004] The excitation electrode, the extraction electrode, the first connection pad, and the second connection pad are not described in detail, but after forming the tuning fork type crystal piece body of the three-arm structure, a metal film for electrode formation is formed on the entire surface of the body, and then the metal film is patterned into a predetermined shape using photolithography technology and metal etching technology. At this time, in order to form the first connection pad and the second connection pad concentrated on the support arm, it is necessary to spend time to electrically divide the metal film provided on the side of the support arm.

[0005] Therefore, in the tuning fork type crystal oscillator with a three-arm structure disclosed in Patent Document 1, cuts are respectively provided from both sides in the width direction of the support arm in the middle of the long side direction of the support arm, and the patterning of the metal film is performed using the inclined surfaces caused by the etching anisotropy of the crystal axis of the crystal generated at the two cuts. In particular, as the cut provided on the -X axis side of the crystal, a cut having a two-step step difference is provided.

[0006] [Prior art literature]

[0007] [Patent Document]

[0008] [Patent Document 1] Japanese Patent Application Publication No. 2022-125526 Summary of the invention

[0009] [Problems to be solved by the invention]

[0010] The idea of ​​using two cuts to divide the metal film as described in Patent Document 1 is specifically as follows. First, the reason for setting the cut on the +X side of the crystal is to use the cut set on the +X side of the crystal to generate a well-known inclined surface that is inclined from the two main surfaces of the support arm to the +X axis side of the crystal. In addition, the reason for setting a two-stage cut on the -X side of the crystal is to improve the situation where the side surface of the -X side of the support arm becomes a vertical wall due to the crystallinity of the crystal, making it difficult to divide the electrode. By setting a two-stage cut on the -X side of the support arm, an inclined surface is intentionally generated to promote the division of the metal film.

[0011] The structure disclosed in Patent Document 1 makes it easy to divide the electrodes in the support arm, but even so, there is room for improvement.

[0012] The present application is made in view of the above-mentioned aspects, and therefore an object of the present invention is to provide a tuning fork type crystal oscillator having a novel structure that can reliably perform electrode division in the support arms of the tuning fork type crystal oscillator having a three-arm structure compared to the past.

[0013] [Technical means to solve the problem]

[0014] In order to achieve the above-mentioned purpose, the tuning fork type crystal oscillator of the present invention comprises: a base; a first vibration arm and a second vibration arm extending from the base in parallel with each other; a support arm extending from the base between the vibration arms; a first excitation electrode and a second excitation electrode arranged on the first vibration arm and the second vibration arm; a first connection pad arranged on the front end side of the support arm and a second connection pad arranged on the base side of the support arm, for connecting the first excitation electrode and the second excitation electrode to the outside; and at least one pair of cutouts, in the middle of the long side direction of the support arm and in the area between the first connection pad and the second connection pad, arranged from both sides along the width direction of the support arm, wherein the tuning fork type crystal oscillator is characterized in that,

[0015] When the X-axis of the crystal parallel to the width direction of the tuning fork type crystal oscillator is defined as the first X-axis, and the X-axes symmetrical at 120 degrees with respect to the first X-axis due to the trigonal system of the crystal are defined as the second X-axis and the third X-axis, respectively,

[0016] The first cutout of the pair of cutouts is a cutout parallel to the first X-axis and terminating in the -X direction of the axis,

[0017] The second cutout of the pair of cutouts is a cutout parallel to the second X-axis or the third X-axis and terminates in the -X direction of the axis.

[0018] When implementing the invention of the tuning fork type crystal oscillator, a third notch parallel to the second X-axis or the third X-axis and terminating in the -X direction of the axis may be included on the front end side of the support arm opposite to the base (seeFigure 2 (B)).

[0019] In addition, when implementing the invention of the tuning fork type crystal oscillator, it may also include one or more third cuts, which are different from the pair of cuts and are parallel to the first X-axis, the second X-axis or the third X-axis in the middle of the long side direction of the support arm and have the -X direction of the axis as the terminal.

[0020] In addition, when implementing the invention of the tuning fork type crystal oscillator, when the first cut, the second cut, and the third cut are provided, the third cut needs to have an appropriate width dimension and depth dimension (in the case of the first cut, the second cut, and the third cut) so that the third cut can have a crystal plane (inclined plane) derived from the +X plane of the crystal and can be easily exposed on the terminal side of the cut. Figure 2 In addition, since the first cut, the second cut, and the third cut are formed by wet etching, the width dimension or the depth dimension also takes into account the thickness of the tuning fork type crystal oscillator ( Figure 1 The specific example is described in the section of the embodiment.

[0021] In addition, if the thickness of the tuning fork type crystal oscillator is too thin, it is difficult to close the terminal of the cut, so it is difficult to produce the desired crystal surface (inclined surface), so the thickness of the tuning fork type crystal oscillator can be set to 50 μm or more, preferably 60 μm or more. On the other hand, if the thickness is too thick, it will be difficult to perform wet etching of the tuning fork, so the upper limit of the thickness can be about the thickness of the current commercially available tuning fork type crystal oscillator, for example, about 100 μm to 120 μm.

[0022] [Effects of the Invention]

[0023] The tuning fork type crystal oscillator of the present invention uses a structure focusing on the 120-degree symmetry of the crystal axis due to the crystal being a trigonal system as an electrode division structure in the support arm of the tuning fork type crystal oscillator of the three-arm structure. That is, it is known that if a cut is set along the X-axis of the crystal with the -X side as the terminal, an inclined surface that becomes a descending slope from the two main surfaces of the cut toward the +X side will be generated in the cut, and the electrode division of the support arm is achieved by causing the phenomenon to occur in the second X-axis or the third X-axis in addition to the first X-axis in the support arm. Therefore, a tuning fork type crystal oscillator can be provided, which has a novel structure that can more reliably perform electrical division between the first connection pad and the second connection pad in the support arm than in the past. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 (A)~ Figure 1(C) is a diagram for explaining the tuning-fork type crystal oscillator 10 according to the first embodiment.

[0025] Figure 2 (A) Figure 2 (B) is a diagram for explaining an example of a tuning fork type crystal oscillator according to another embodiment.

[0026] Figure 3 (A)~ Figure 3 (C) is an electron microscope (SEM) photograph of the first cut and the second cut of the element of the example of the tuning fork type crystal oscillator 10 according to the first embodiment.

[0027] Figure 4 (A)~ Figure 4 (C) is a diagram for explaining an example of a crystal device using the tuning fork type crystal oscillator 10 according to the first embodiment.

[0028] Figure 5 (A) Figure 5 (B) is a diagram for explaining an example of a method of manufacturing the tuning-fork type crystal oscillator 10 according to the first embodiment.

[0029] [Explanation of Symbols]

[0030] 10: Tuning Fork Type Crystal Oscillator of First Embodiment (Tuning Fork Type Crystal Oscillator)

[0031] 10a: Appearance

[0032] 11: Base

[0033] 13a: First vibration arm

[0034] 13b: Second vibration arm

[0035] 13c: Slot

[0036] 13cx: Window

[0037] 15: Support arm

[0038] 15a: First incision (incision)

[0039] 15aa, 15ba: inclined surface

[0040] 15ax: Opening for forming the first cut

[0041] 15b: Second incision (incision)

[0042] 15bx: Opening for forming the second cut

[0043] 15c: Another example of the second incision (second incision)

[0044] 15d: Third incision

[0045] 17a: First excitation electrode (excitation electrode)

[0046] 17ax: First connection pad

[0047] 17b: Second excitation electrode (excitation electrode)

[0048] 17bx: Second connection pad

[0049] 20, 30: Tuning fork crystal oscillator

[0050] 50: Crystal devices (piezoelectric devices)

[0051] 51: Container

[0052] 51a: concave part

[0053] 51b: Connecting pad

[0054] 51c: External mounting terminal

[0055] 53: Conductive adhesive

[0056] 55: Cover member

[0057] D1: Depth of the first cut (depth dimension)

[0058] D3: Depth of the third cut (depth dimension)

[0059] D21: The first depth dimension of the second incision (first depth dimension)

[0060] D22: The second depth dimension of the second cutout (the second depth dimension) (the depth dimension)

[0061] W0: Width of the support arm

[0062] W1: Width dimension of the first cut (width dimension)

[0063] W2: Width dimension of the second cut (width dimension) (width)

[0064] W3: Width dimension of the third cut (width dimension)

[0065] Wa: Intermediate wafer (crystal wafer)

[0066] X1: First X axis

[0067] X2: Second X axis

[0068] X3: The third X axis

[0069] Y': Axis

[0070] Z': Axis DETAILED DESCRIPTION

[0071] Hereinafter, the embodiment of the tuning fork type crystal oscillator of the present invention will be described with reference to the accompanying drawings. In addition, each figure used for explanation is only shown in outline to the extent that the present invention can be understood. In addition, in each figure used for explanation, the same components are marked with the same reference numerals, and their description is sometimes omitted. In addition, the shapes, sizes, materials, etc. described in the following description are only preferred examples within the scope of the present invention. Therefore, the present invention is not limited to the following embodiments.

[0072] 1. Tuning-fork crystal oscillator 10 of the first embodiment

[0073] Figure 1 (A)~ Figure 1 (C) is an explanatory diagram of the tuning fork type crystal oscillator 10 of the first embodiment. In particular, Figure 1 (A) is a development diagram showing the front, back and side surfaces of the tuning fork type crystal oscillator 10. Figure 1 (B) is along Figure 1 A cross-sectional view of the PP line of (A). In addition, Figure 1 (C) is a cross-sectional view of the vicinity of the second incision 15b cut along the QQ line. Figure 1 In the development diagram of (A), by folding the diagram back and connecting at the position of α-α, a three-dimensional tuning fork type crystal oscillator 10 can be formed. Here, Figure 1 The coordinate axes in (A) are the crystal axes of the crystal corresponding to the tuning fork portion on the right side of this figure. In the coordinate axes, X1 is the first X-axis of the crystal, and X2 is the second X-axis of the crystal. In the case of the example, X1, which is the first X-axis of the crystal, is an axis parallel to the width direction of the tuning fork type crystal oscillator 10. In addition, X2, which is the second X-axis, is an axis located at a position 120° symmetrical with respect to X1, which is the first X-axis, with the Z-axis of the crystal as the rotation center due to the trigonal system of the crystal. In addition, the Y' axis and the Z' axis are represented as axes that are offset by a specified angle depending on the known direction angle of the tuning fork type crystal oscillator 10 relative to the Y-axis and the X-axis of the crystal.

[0074] The tuning fork type crystal oscillator 10 of the first embodiment includes: a base 11; a first vibration arm 13a and a second vibration arm 13b, extending from the base 11 in parallel with each other; a support arm 15, extending from the base between the vibration arms; a first excitation electrode 17a and a second excitation electrode 17b, arranged on the first vibration arm and the second vibration arm; a first connection pad 17ax set to lead out wiring on the front end side of the support arm and a second connection pad 17bx set on the base side of the support arm, which are used to connect the first excitation electrode and the second excitation electrode to the outside; and a first cutout 15a and a second cutout 15b as at least a pair of cuts, which are set from both sides along the width direction of the support arm in the middle of the long side direction of the support arm and in the area between the first connection pad and the second connection pad.

[0075] Moreover, the first cutout 15a is a cutout parallel to the first X-axis X1 and having the -X direction of the axis as the terminal. The second cutout 15b is a cutout parallel to the second X-axis X2 and having the -X direction of the axis as the terminal. The second cutout 15b in the above case is a cutout that opens in the direction of the front end side of the support arm 15 and in a slightly inclined direction. When the second cutout 15b is open on the front end side of the support arm, when the resist in the second cutout 15b is developed using photolithography technology or when metal etching is performed, the developer or metal etching easily enters the inside of the cutout, so it is considered to be preferred for the development of the resist or the metal etching during the patterning of the metal film.

[0076] In the tuning fork type crystal oscillator 10 of the first embodiment, grooves 13c are provided on the front and back of each of the first vibration arm 13a and the second vibration arm 13b (see Figure 1 (B)). Although the groove 13c is not necessarily provided, if the groove 13c is provided, the electric field efficiency in each vibration arm is improved compared to the case where the groove 13c is not provided, so that the driving of the tuning fork type crystal oscillator becomes easier (the crystal impedance can be reduced).

[0077] Here, along Figure 1 The cross section obtained by cutting the first incision 15a along the PP line in (A) is as follows Figure 1 As shown in (B), the shape includes an inclined surface 15aa that descends from the front and back of the support arm 15 along the first X-axis X1. Figure 1 The cross section obtained by cutting the second incision 15b along the QQ line in (C) is as follows: Figure 1As shown in (C), the shape includes the inclined surface 15ba descending from the front and back of the support arm 15 along the second X-axis X2. These inclined surfaces including the inclined surface 15aa descending toward the +X axis, or the inclined surface including 15ba are well-known shapes caused by the etching anisotropy of the X-axis, Y-axis, and Z-axis of the crystal, but in the present invention, it is characterized by the following aspects: the electrode division is implemented by using the special inclined surfaces of the two X axes generated with 120° symmetry.

[0078] In this way, when the cuts 15a and 15b are set using two X axes, the inclined surface can be used to reliably divide the wiring from the excitation electrodes 17a and 17b to the support arm 15 and reach the first connecting pads 17ax and the second connecting pads 17bx on the side of the support arm 15.

[0079] 2. Tuning fork type crystal oscillator according to another embodiment

[0080] Next, refer to Figure 2 (A) Figure 2 (B) describes a tuning fork type crystal oscillator according to another embodiment.

[0081] First, the second embodiment will be described. Figure 2 (A) is a plan view for explaining a tuning fork type crystal oscillator 20 of the second embodiment. The tuning fork type crystal oscillator 20 of the second embodiment is different from the tuning fork type crystal oscillator 10 of the first embodiment in the structure of the second cutout. That is, in the tuning fork type crystal oscillator 10 of the first embodiment, the second cutout 15b (refer to Figure 1 (A)) is arranged to be parallel to the second X-axis located at a 120-degree symmetrical position in the positive direction with respect to the first X-axis with the Z-axis as the rotation center and the -X direction of the axis is the terminal. In contrast, in the case of the second embodiment, the second notch 15c (refer to Figure 2 (A)) is arranged to rotate about the Z axis relative to the first X axis. Figure 1 The second cutout 15c in this case is parallel to the third X-axis located at a 120-degree symmetrical position in the opposite direction of (A) and terminates in the -X direction of the axis. In this case, the second cutout 15c is opened in the base side direction of the support arm 15, and is actually opened in a slightly inclined direction.

[0082] In the case of the tuning fork type crystal oscillator 20 of the second embodiment, the electrode division using two predetermined inclined surfaces along the +X axis can be performed similarly to the first embodiment.

[0083] Next, a third embodiment will be described. Figure 2(B) is a plan view for explaining a tuning fork type crystal oscillator 30 of the third embodiment. The tuning fork type crystal oscillator 30 of the third embodiment is different from the tuning fork type crystal oscillator 10 of the first embodiment in that a third notch 15d is provided. That is, in the tuning fork type crystal oscillator 30 of the third embodiment, a third notch 15d is provided at the front end of the support arm 15, which is parallel to X2 as the second X-axis and terminates in the -X direction of the axis.

[0084] In the case of the tuning fork type crystal oscillator 30 of the third embodiment, the electrode division on the side surface of the support arm can be performed at three locations.

[0085] In the tuning fork type crystal oscillator 30 of the third embodiment, the tip of the support arm 15 is shaped as an inclined shape having a contour orthogonal to the second X-axis X2. With such an inclined shape, the third notch 15d can be formed more easily than with a non-inclined shape.

[0086] In addition, of course, you can also Figure 2 The tuning fork type crystal oscillator 20 of the second embodiment shown in (A) is provided with Figure 2 The third incision 15d shown in (B).

[0087] In each of the above embodiments, it is important to Figure 2 The width dimension W1 and the depth dimension D1 of the first cutout 15a shown in (B), the width dimension W2, the first depth dimension D21 and the second depth dimension D22 of the second cutout 15b, and the width dimension W3 and the depth dimension D3 of the third cutout 15d are respectively determined to be appropriate width dimensions and depth dimensions that can form a predetermined crystal plane (inclined surface) at the terminal of the cutout to properly perform electrode division and the strength of the support arm will not be reduced. Although not limited to this, for example, when the width dimension of the support arm is defined as W0, W1, W2, W3, D1, D21, D22, and D3 can be set to, for example, a dimension selected from 0.1W0 to 0.4W0, preferably 0.15W0 to 0.35W0, and more preferably 0.15W0 to 0.30W0.

[0088] In addition, in particular, Figure 2As shown in (B), the depth dimension of the second cutout 15b is expressed as D21 and D22, but the second cutout 15b in the described case intersects obliquely with respect to the support arm 15, thereby generating a first depth dimension D21 with a deeper depth and a second depth dimension D22 with a shallower depth, and is therefore recorded as such. Moreover, the depth dimension that has a great influence on the situation in which a crystal plane is generated in the second cutout 15b is the second depth dimension D22 with a short depth dimension. That is, in the case of the present invention, with respect to the second cutout 15b, if the second depth dimension D22 is too short, the desired crystal plane cannot be generated. Therefore, with respect to the second cutout 15b, the size of the second depth dimension D22 becomes important. In this regard, the following is an example of trial-produced elements of the tuning fork type crystal oscillator 10 of the first embodiment.

[0089] Figure 3 This is an electron microscope (Scanning Electron Microscope (SEM)) photograph of an element of the tuning fork type crystal oscillator 10 of the first embodiment, which is actually produced. In particular, it focuses on the support arm 15, the first notch 15a and the second notch 15b. In particular, Figure 3 (A) is a flat photo. Figure 3 (B) is along Figure 3 The cross-sectional photograph of the RR line in (A) is Figure 3 (C) is along Figure 3 (A) is a cross-sectional photograph of the SS line.

[0090] The inventor of the present application set the thickness of the tuning fork type crystal oscillator to 100 μm, and varied the width W2 and the second depth dimension D22 of the second cutout 15b to multiple levels and conducted various trials. As a result, it can be seen that in order to form the desired crystal plane at the terminal end of the second cutout 15b, the width W2 and the second depth dimension D22 of the second cutout can be greater than 10 μm, preferably greater than 20 μm, and more preferably greater than 25 μm. In addition, the upper limit of the depth dimension D22 is determined so that the strength of the support arm 15 will not be reduced. Although not limited to this, Figure 3 In the case of the prototype element shown, the width dimension W2 was set to 30 μm, and the depth dimension D22 was set to 40 μm. In the case of the element described above, the width W0 of the support arm was set to 260 μm.

[0091] The conditions of the width W2 and the second depth D22 of the second notch 15 b are also applicable to the case where the third notch 15 d is provided in an inclined arrangement relationship with respect to the support arm 15 .

[0092] In addition, it is clear that if the thickness of the tuning fork type crystal oscillator is too thin, it is difficult for the inclined surface originating from the crystal surface to remain at the terminal of the first incision, the second incision, and the third incision. It can be seen that in order to avoid this situation, the thickness of the tuning fork type crystal oscillator can be set to 50 μm or more, preferably 60 μm or more. Among them, if the thickness of the tuning fork type crystal oscillator is too thick, wet etching will become difficult, so the upper limit of the thickness can be, for example, about 100 μm to 120 μm used in commercially available tuning forks.

[0093] In addition, in the embodiment, an example is shown in which a pair of first cutouts 15a and second cutouts 15b are provided in the support arm 15, but one or more third cutouts may be included, and the third cutouts are different from the pair of cutouts and are parallel to the first X-axis, the second X-axis or the third X-axis in the middle of the long side direction of the support arm and terminate in the -X direction of the axis. Electrode segmentation can be performed more reliably.

[0094] 2. Examples of crystal devices

[0095] The tuning fork type crystal oscillator of the present invention can be used as a crystal oscillator and a tuning fork type crystal oscillator for constituting various crystal devices represented by crystal oscillators. As an example for deepening understanding, an example of a crystal device 50 using the tuning fork type crystal oscillator 10 of the first embodiment is described. Figure 4 (A)~ Figure 4 The diagram (C) is used for this purpose, in particular, Figure 4 (A) is a plan view, Figure 4 (B) is Figure 4 PP line profile in (A), Figure 4 (C) is the rear view.

[0096] The crystal device 50 uses a ceramic container 51 having a recess 51a for accommodating the tuning fork type crystal oscillator 10. A connection pad 51b on the container side is provided on the bottom surface of the recess 51a. An external mounting terminal 51c is provided on the outer bottom surface of the container 51. The connection pad 51b and the external mounting terminal 51c are connected by a through-hole wiring not shown.

[0097] The tuning fork type crystal oscillator 10 is connected and fixed to the container 51 by a conductive adhesive 53 at the positions of the first connection pad 17ax and the second connection pad 17bx of the support arm 15 and the connection pad 51b on the container side. A cover member 55 is joined to the top surface of the container 51 to seal the tuning fork type crystal oscillator 10 in the container 51.

[0098] Furthermore, in the above, the crystal device including the container 51 having the recessed portion 51 a as the container is exemplified, but the container is not limited to the example, and may be any appropriate container.

[0099] 3. Example of manufacturing method

[0100] Next, in order to deepen the understanding of the tuning-fork type crystal oscillator of the present invention, an example of a method of manufacturing the tuning-fork type crystal oscillator 10 according to the first embodiment will be described. Figure 5 (A) Figure 5 (B) is an illustration for this purpose.

[0101] In the above-mentioned method, first, Figure 5 As shown in (A), a plurality of the outer shapes 10a of the tuning fork type crystal oscillators including a base, a first vibration arm, a second vibration arm, and a support arm are formed in a matrix on a crystal wafer Wa. This can be performed by well-known film forming technology, photolithography technology, and wet etching technology.

[0102] Specifically, a metal film is formed on both main surfaces of the crystal wafer Wa, and then a resist pattern covering the outer shape 10a of the tuning fork and the crosspieces (not shown) that hold the outer shapes of the tuning fork are formed on the crystal wafer. Then, the metal film is selectively etched using the resist pattern as a mask. Thereafter, the crystal wafer is immersed in a hydrofluoric acid-based etchant to obtain a wafer having a plurality of tuning fork pieces corresponding to the outer shape 10a arranged in a matrix.

[0103] Then, if Figure 5 As shown in (B), an etching mask having a first cutout forming opening 15ax for forming a first cutout and a second cutout forming opening 15bx for forming a second cutout is formed on the crystal wafer Wa where the outer shape 10a is formed. Then, the crystal wafer is immersed in a hydrofluoric acid-based etchant. The process is preferably performed together with a process of forming a window 13cx for forming a groove on the vibration arm, which is performed in this embodiment. After the etching process is completed, a Figure 1 The structures of the first notch 15a and the second notch 15b of the tuning fork type crystal oscillator 10 of the first embodiment are shown.

[0104] Thereafter, a metal film for forming an excitation electrode is formed on the entire surface of the crystal wafer, and then the metal film is patterned to form a first excitation electrode and a second excitation electrode, and a first connection pad and a second connection pad. In the patterning step, the first connection pad and the second connection pad can be electrically divided using an inclined surface generated on the specified +X side of the first incision and the second incision. The crystal wafer thus formed is an intermediate wafer for manufacturing a tuning fork type crystal oscillator 10. In addition, by singulating the tuning fork type crystal oscillator 10 from the intermediate wafer and mounting it on, for example, Figure 4 In the container 51 shown, a piezoelectric device 50 can be manufactured.

Claims

1. A tuning fork type crystal oscillator, comprising: base; A first vibration arm and a second vibration arm extend parallel to each other from the base; a support arm extending from the base between the vibrating arms; A first excitation electrode and a second excitation electrode are arranged on the first vibration arm and the second vibration arm; a first connection pad arranged on the front end side of the support arm and a second connection pad arranged on the base side of the support arm are used to connect the first excitation electrode and the second excitation electrode to the outside; and at least one pair of cutouts are arranged from both sides along the width direction of the support arm in the middle of the long side direction of the support arm and in the area between the first connection pad and the second connection pad. The tuning fork type crystal oscillator is characterized in that: When the X-axis of the crystal parallel to the width direction of the tuning fork type crystal oscillator is defined as the first X-axis, and the X-axes symmetrical at 120 degrees with respect to the first X-axis due to the trigonal system of the crystal are defined as the second X-axis and the third X-axis, respectively, The first cutout of the pair of cutouts is a cutout parallel to the first X-axis and terminating in the -X direction of the axis, The second cutout of the pair of cutouts is a cutout parallel to the second X-axis or the third X-axis and terminates in the -X direction of the axis.

2. The tuning fork type crystal oscillator according to claim 1, characterized in that: The first cutout and the second cutout each include an inclined surface that descends from the front and back surfaces of the support arm toward the +X axis direction of each cutout.

3. The tuning fork type crystal oscillator according to claim 1, characterized in that: The second cutout opens at the front end side of the support arm.

4. The tuning fork type crystal oscillator according to claim 1, characterized in that: The second cutout opens at the base side of the support arm.

5. The tuning fork type crystal oscillator according to claim 1, characterized in that: When the width dimension of the first incision is defined as W1, the depth dimension is defined as D1, the width dimension of the second incision is defined as W2, the first depth dimension is defined as D21, the second depth dimension is defined as D22, and the width dimension of the support arm is defined as W0, W1, D1, W2, D21 and D22 are respectively the same or different dimensions selected from 0.1W to 0.4W, wherein the first depth dimension D21 and the second depth dimension D22 are the left and right depth dimensions of the second incision, and are in the relationship of D21>D22.

6. The tuning fork type crystal oscillator according to claim 1, characterized in that: When the width dimension of the second cutout is defined as W2 and the depth dimension of the shorter side of the left and right depth dimensions of the second cutout is defined as a second depth dimension D22, The width dimension W2 and the second depth dimension D22 are respectively the same or different in size from a range of 10 μm or more.

7. The tuning fork type crystal oscillator according to claim 1, characterized in that: When the thickness of the tuning fork type crystal oscillator is defined as T, T is 60 μm or more.

8. A crystal device, characterized in that include: A tuning fork type crystal oscillator according to any one of claims 1 to 7, and a container for mounting the tuning fork type crystal oscillator.

9. An intermediate wafer for manufacturing a tuning fork type crystal oscillator, characterized in that: A plurality of tuning fork type crystal oscillators according to any one of claims 1 to 7 are included in a matrix.

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