Method for manufacturing vibration element

Abstract

A method for manufacturing a vibrating element. A method for manufacturing a vibrating element capable of suppressing deviations in groove depth is provided. The method for manufacturing a vibrating element includes: a first protective film forming step, forming a first protective film on a first surface of a quartz substrate; a first dry etching step, dry etching the quartz substrate from the first surface side through the first protective film to form the outlines of a first groove, a first vibrating arm, and a second vibrating arm on the first surface; a second protective film forming step, forming a second protective film on a second surface of the quartz substrate; and a second dry etching step, dry etching the quartz substrate from the second surface side through the second protective film to form the outlines of a second groove, a first vibrating arm, and a second vibrating arm on the second surface, wherein, when the depths of the first and second grooves formed in the first and second dry etching steps are Wa, and the depths of the outlines formed in the first and second dry etching steps are Aa, Wa / Aa < 1 is satisfied in at least one of the first and second dry etching steps.

Description

Technical Field

[0001] This invention relates to a method for manufacturing a vibrating element. Background Technology

[0002] Patent Document 1 discloses a method for manufacturing a vibrating element, which forms a vibrating element having a pair of vibrating arms with grooves by dry etching. In this manufacturing method, by narrowing the width of the groove relative to the width between the pair of vibrating arms, the etching depth of the groove is made shallower relative to the etching depth between the pair of vibrating arms by utilizing the micro-load effect, thereby forming the groove and the outer shape of the vibrating element.

[0003] Patent Document 1: Japanese Patent Application Publication No. 2007-013382

[0004] However, in the manufacturing method of the vibration element in Patent Document 1, there is a problem: if the dry etching time deviates, the depth of the groove deviates, and the vibration characteristics of the vibration element deviate accordingly. Summary of the Invention

[0005] In the manufacturing method of the vibration element of the present invention, the vibration element has: a base; and a first vibration arm and a second vibration arm, which extend from the base along a first direction and are arranged along a second direction intersecting the first direction. The first vibration arm and the second vibration arm each have: a first surface and a second surface arranged in opposite directions in a third direction intersecting the first direction and the second direction; a bottomed first groove opening on the first surface; and a bottomed second groove opening on the second surface. The manufacturing method includes: a preparation step of preparing a quartz substrate having the first surface and the second surface; a first protective film forming step of forming a first protective film on the first surface of the quartz substrate, except for the first groove forming region where the first groove is formed and the inter-arm region located between the first vibration arm forming region where the first vibration arm is formed and the second vibration arm forming region where the second vibration arm is formed; and a first dry etching step of etching the first protective film. A protective film is dry-etched onto the quartz substrate from the first surface side to form the first groove, the first vibrating arm, and the outline of the second vibrating arm on the first surface; a second protective film forming process is performed to form a second protective film on the second surface of the quartz substrate, except for the second groove forming area and the inter-arm area; and a second dry etching process is performed to dry-etch the quartz substrate from the second surface side through the second protective film to form the second groove, the first vibrating arm, and the outline of the second vibrating arm on the second surface. When the depth of the first groove formed in the first dry etching process and the depth of the second groove formed in the second dry etching process are Wa, and the depth of the outline formed in the first dry etching process and the depth of the outline formed in the second dry etching process are Aa, Wa / Aa < 1 is satisfied in at least one of the first and second dry etching processes. Attached Figure Description

[0006] Figure 1 This is a top view illustrating a preferred embodiment of the vibration element of the present invention.

[0007] Figure 2 yes Figure 1 Sectional view along line A1-A1 in the diagram.

[0008] Figure 3 It is shown Figure 1 A diagram illustrating the manufacturing process of the vibrating element.

[0009] Figure 4 It is used for explanation Figure 1 A cross-sectional view of the manufacturing method.

[0010] Figure 5 It is used for explanation Figure 1A cross-sectional view of the manufacturing method.

[0011] Figure 6 It is used for explanation Figure 1 A cross-sectional view of the manufacturing method.

[0012] Figure 7 It is used for explanation Figure 1 A cross-sectional view of the manufacturing method.

[0013] Figure 8 It is used for explanation Figure 1 A cross-sectional view of the manufacturing method.

[0014] Figure 9 It is used for explanation Figure 1 A cross-sectional view of the manufacturing method.

[0015] Figure 10 It is used for explanation Figure 1 A cross-sectional view of the manufacturing method.

[0016] Figure 11 It is a graph showing the relationship between W / A and Wa / Aa when different etching times are applied.

[0017] Figure 12 It is a graph showing the relationship between W / A and Wa / Aa under different conditions of reactant gases.

[0018] Figure 13 This is a graph showing the relationship between Wa / Aa and CI values.

[0019] Figure 14 This is a top view showing a modified example of the vibrating element.

[0020] Figure 15 yes Figure 14 Sectional view along line A2-A2.

[0021] Figure 16 This is a top view showing a modified example of the vibrating element.

[0022] Figure 17 yes Figure 16 Sectional view along line A3-A3 in the diagram.

[0023] Figure 18 This is a top view showing a modified example of the vibrating element.

[0024] Figure 19 yes Figure 18 Sectional view along line A4-A4 in the diagram.

[0025] Figure 20 yes Figure 18 Sectional view along line A5-A5.

[0026] Figure 21 This is a top view showing a modified example of the vibrating element.

[0027] Figure 22 yes Figure 21 Sectional view along line A6-A6 in the diagram.

[0028] Figure 23 yes Figure 21 Sectional view along line A7-A7 in the diagram.

[0029] Label Explanation

[0030] 1. Vibrating element; 1A. Vibrating element; 2. Vibrating substrate; 2A. First surface; 2B. Second surface; 20. Quartz substrate; 21. Base; 22. First vibrating arm; 221. First groove; 222. Second groove; 23. Second vibrating arm; 231. First groove; 232. Second groove; 3. Electrode; 31. Signal electrode; 32. Ground electrode; 5. First protective film; 51. Opening; 52. Opening; 53. Opening; 6. Second protective film; 61. Opening; 62. Opening; 63. Opening; 7. Double tuning fork type vibrating element; 7A. First surface; 7B. Second surface; 711. Base; 712. Base; 72 First vibrating arm; 721 First slot; 722 Second slot; 73 Second vibrating arm; 731 First slot; 732 Second slot; 8 Gyroscope vibration element; 8A First surface; 8B Second surface; 81 Base; 82 Detection vibrating arm; 821 First slot; 822 Second slot; 83 Detection vibrating arm; 831 First slot; 832 Second slot; 84 Connecting arm; 85 Connecting arm; 86 Driving vibrating arm; 861 First slot; 862 Second slot; 87 Driving vibrating arm; 871 First slot; 872 Second slot; 88 Driving vibrating arm; 881 First slot ; 882 Slot 2; 89 Drive Vibration Arm; 891 Slot 1; 892 Slot 2; 9 Gyroscope Vibration Element; 9A Surface 1; 9B Surface 2; 91 Base; 92 Drive Vibration Arm; 921 Slot 1; 922 Slot 2; 93 Drive Vibration Arm; 931 Slot 1; 932 Slot 2; 94 Detection Vibration Arm; 941 Slot 1; 942 Slot 2; 95 Detection Vibration Arm; 951 Slot 1; 952 Slot 2; A Width; Aa Depth; B Width; Ba Depth; G1 Gas Type; G2 Gas Type; G3 Gas Type; M 1. Metal film; M2. Metal film; P region; PP region; Q1. First trench forming region; Q2. First vibrating arm forming region; Q3. Second vibrating arm forming region; Q4. Inter-arm region; Q5. Inter-component region; Q6. Second trench forming region; R1. First resist film; S1. Preparation process; S2. First protective film forming process; S3. First dry etching process; S4. Second protective film forming process; S5. Second dry etching process; S6. Electrode forming process; SD arrow; SS arrow; Ta thickness; W width; Wa depth; ωy angular velocity; ωz angular velocity. Detailed Implementation

[0031] Hereinafter, the manufacturing method of the vibration element of the present invention will be described in detail with reference to the embodiments shown in the accompanying drawings.

[0032] Figure 1 This is a top view illustrating a preferred embodiment of the vibration element of the present invention. Figure 2 yes Figure 1 Sectional view along line A1-A1 in the diagram. Figure 3 It is shown Figure 1 A diagram illustrating the manufacturing process of the vibrating element. Figures 4 to 10 These are for explanation Figure 1 A cross-sectional view of the manufacturing method. Figure 11 It is a graph showing the relationship between W / A and Wa / Aa when different etching times are applied. Figure 12 It is a graph showing the relationship between W / A and Wa / Aa under different conditions of reactant gases. Figure 13 This is a graph showing the relationship between Wa / Aa and CI values. Figure 14 This is a top view showing a modified example of the vibrating element. Figure 15 yes Figure 14 Sectional view along line A2-A2. Figure 16 This is a top view showing a modified example of the vibrating element. Figure 17 yes Figure 16 Sectional view along line A3-A3 in the diagram. Figure 18 This is a top view showing a modified example of the vibrating element. Figure 19 yes Figure 18 Sectional view along line A4-A4 in the diagram. Figure 20 yes Figure 18 Sectional view along line A5-A5. Figure 21 This is a top view showing a modified example of the vibrating element. Figure 22 yes Figure 21 Sectional view along line A6-A6 in the diagram. Figure 23 yes Figure 21 Sectional view along line A7-A7 in the diagram.

[0033] In addition, for ease of explanation, except Figure 3 , Figures 11 to 13 In the figures other than those shown, the X-axis, Y-axis, and Z-axis are shown as three mutually orthogonal axes. The direction along the X-axis is also referred to as the X-axis direction (second direction), the direction along the Y-axis as the Y-axis direction (first direction), and the direction along the Z-axis as the Z-axis direction (third direction). The arrow side of each axis is also referred to as the positive side, and the opposite side as the negative side. The positive side of the Z-axis direction is also referred to as "up," and the negative side as "down." The view from the Z-axis direction is also simply referred to as "top view." Furthermore, as described later, the X-axis, Y-axis, and Z-axis correspond to the crystal axes of quartz.

[0034] Before explaining the manufacturing method of the vibrating element 1, according to Figure 1 and Figure 2 The structure of the vibrating element 1 is described below. The vibrating element 1 is a tuning fork type vibrating element, having a vibrating substrate 2 and an electrode 3 formed on the front side of the vibrating substrate 2.

[0035] The vibrating substrate 2 is formed by patterning a Z-cut quartz substrate (Z-cut quartz plate) into a desired shape. It has a width in the XY plane defined by the X-axis and Y-axis, which are the crystal axes of quartz, and a thickness in the Z-axis direction. The X-axis is also called the electrical axis, the Y-axis is also called the mechanical axis, and the Z-axis is also called the optical axis.

[0036] The vibrating substrate 2 is plate-shaped and has a first surface 2A and a second surface 2B arranged opposite each other in the Z-axis direction. Furthermore, the vibrating substrate 2 has a base 21 and a first vibrating arm 22 and a second vibrating arm 23 extending from the base 21 in the Y-axis direction and arranged in the X-axis direction.

[0037] The first vibrating arm 22 has a first groove 221 with a bottom that opens on a first surface 2A and a second groove 222 with a bottom that opens on a second surface 2B. Similarly, the second vibrating arm 23 has a first groove 231 with a bottom that opens on a first surface 2A and a second groove 232 with a bottom that opens on a second surface 2B. These grooves 221, 222, 231, and 232 extend along the Y-axis. Therefore, the first vibrating arm 22 and the second vibrating arm 23 each have a generally U-shaped cross-sectional shape. Thus, they become a vibrating element 1 with reduced thermoelastic losses and excellent vibration characteristics.

[0038] Electrode 3 has a signal electrode 31 and a ground electrode 32. The signal electrode 31 is disposed on the first surface 2A and the second surface 2B of the first vibrating arm 22, and on both sides of the second vibrating arm 23. Conversely, the ground electrode 32 is disposed on both sides of the first vibrating arm 22 and on the first surface 2A and the second surface 2B of the second vibrating arm 23. When a drive signal is applied to the signal electrode 31 while the ground electrode 32 is grounded, such as... Figure 1 As shown by the arrows, the first vibrating arm 22 and the second vibrating arm 23 undergo bending vibration in the X-axis direction by repeatedly approaching and separating.

[0039] The above provides a brief description of the vibrating element 1. Next, the manufacturing method of the vibrating element 1 will be described. For example... Figure 3As shown, the manufacturing method of the vibrating element 1 includes: a preparation step S1, preparing a quartz substrate 20 as the parent material for the vibrating substrate 2; a first protective film formation step S2, forming a first protective film 5 on the first surface 2A of the quartz substrate 20; a first dry etching step S3, dry etching the quartz substrate 20 from the first surface 2A side through the first protective film 5; a second protective film formation step S4, forming a second protective film 6 on the second surface 2B of the quartz substrate 20; a second dry etching step S5, dry etching the quartz substrate 20 from the second surface 2B side through the second protective film 6; and an electrode formation step S6, forming an electrode 3 on the front side of the vibrating substrate 2 obtained through the above steps. These steps will be described sequentially below.

[0040] Preparation Process S1

[0041] like Figure 4 As shown, a quartz substrate 20 is prepared as the base material for the vibrating substrate 2. The quartz substrate 20 is adjusted to the desired thickness by CMP (chemical mechanical polishing) or the like, and has a sufficiently smooth first surface 2A and second surface 2B. Multiple vibrating elements 1 are formed together from the quartz substrate 20.

[0042] Step S2: Forming the First Protective Film

[0043] like Figure 5 As shown, metal films M1 and M2 are formed on the first surface 2A and the second surface 2B of the quartz substrate 20. Next, a first resist film R1 is formed on the metal film M1, and the formed first resist film R1 is patterned. Then, a first protective film 5 is formed at the opening of the first resist film R1, and then the first resist film R1 is removed. Thus, a [structure / structure] is formed. Figure 6 That's right. As for the first protective film 5, as long as it is etch-resistant, there are no special limitations; various metal masks such as nickel masks can be used.

[0044] The first protective film 5 has openings 51, 52, and 53 in the portion of the quartz substrate 20 to be removed. Opening 51 overlaps with the first groove forming region Q1 that forms the first grooves 221 and 231. Opening 52 overlaps with the inter-arm region Q4 located between the first vibrating arm forming region Q2 that forms the first vibrating arm 22 and the second vibrating arm forming region Q3 that forms the second vibrating arm 23. Opening 53 overlaps with the inter-element region Q5 located between adjacent vibrating substrates 2. In other words, the first protective film 5 is formed except for the first groove forming region Q1, the inter-arm region Q4, and the inter-element region Q5.

[0045] First Dry Etching Process S3

[0046] like Figure 7As shown, the quartz substrate 20 is dry-etched from the first surface 2A side隔着第1保护膜5从第1面2A侧对石英基板20进行干蚀刻,在第1面2A同时形成槽221、231和振动基板2的外形。另外,所述“同时形成”是在1个工序中一并形成两者。更具体而言,本工序是反应性离子蚀刻,使用RIE(反应离子蚀刻)装置进行。另外,作为导入到RIE装置的反应气体,没有特别限定,例如可以使用SF6、CF4、C2F4、C2F6、C3F6、C4F8等。while simultaneously forming the grooves 221 and 231 and the outer shape of the vibrating substrate 2 on the first surface 2A隔着第1保护膜5从第1面2A侧对石英基板20进行干蚀刻,在第1面2A同时形成槽221、231和振动基板2的外形。另外,所述“同时形成”是在1个工序中一并形成两者。更具体而言,本工序是反应性离子蚀刻,使用RIE(反应离子蚀刻)装置进行。另外,作为导入到RIE装置的反应气体,没有特别限定,例如可以使用SF6、CF4、C2F4、C2F6、C3F6、C4F8等。through the first protective film 5. Here, the "simultaneous formation" means forming both in one process. More specifically, this process is reactive ion etching and is performed using a RIE (Reactive Ion Etching) apparatus. Additionally, the reaction gas introduced into the RIE apparatus is not particularly limited, and for example, SF6, CF4, C2F4, C2F6, C3F6, C4F8, etc. can be used.

[0047] This process ends when the first grooves 221 and 231 reach the desired depth. Here, in dry etching, the "microloading effect" is known, where the higher the pattern density of the first protective film 5, the lower the etching rate. In this embodiment, the width W in the X-axis direction of the first grooves 221 and 231 is compared with the width A in the X-axis direction of the inter-arm region Q4, and W < A. Also, the width W is compared with the width B in the X-axis direction of the inter-element region Q5, and W < B. Therefore, due to the microloading effect, the etching rate of the first groove formation region Q1 is lower than the etching rates of the inter-arm region Q4 and the inter-element region Q5. Thus, at the end of this process, the depth Wa of the first grooves 221 and 231 is shallower than the depths Aa and Ba of the outer shape of the vibrating substrate 2. That is, Wa < Aa (Wa / Aa < 1), and Wa < Ba (Wa / Ba < 1). Additionally, the depths Aa and Ba are each more than half the thickness of the quartz substrate 20. That is, if the thickness of the quartz substrate is Ta, then Aa ≥ 0.5Ta and Ba ≥ 0.5Ta. Furthermore, the depth Wa, the depth Aa, and the depth Ba are respectively defined as the deepest depth in the regions of the width W, the width A, and the width B.本工序在第1槽221、231成为希望的深度的时刻结束。在此,在干蚀刻中,已知第1保护膜5的图案密度越高、蚀刻速率越低的“微负载效应”。在本实施方式中,对第1槽221、231的X轴方向上的宽度W和臂间区域Q4的X轴方向上的宽度A进行比较,W<A。另外,对宽度W和元件间区域Q5的X轴方向上的宽度B进行比较,W<B。因此,通过微负载效应,第1槽形成区域Q1的蚀刻速率低于臂间区域Q4和元件间区域Q5的蚀刻速率。因此,在本工序结束时刻,第1槽221、231的深度Wa比振动基板2的外形的深度Aa、Ba浅。即,Wa<Aa(Wa / Aa<1),Wa<Ba(Wa / Ba<1)。另外,深度Aa、Ba分别为石英基板20的厚度一半以上。即,如果设石英基板的厚度为Ta,则Aa≥0.5Ta,Ba≥0.5Ta。此外,深度Wa、深度Aa以及深度Ba分别定义为宽度W、宽度A以及宽度B的区域中的最深部的深度。

[0048] After this process ends, the first protective film 5 and the metal film M1 are removed, and the process proceeds to the processing of the back surface of the quartz substrate 20.在本工序结束后,去除第1保护膜5和金属膜M1,转移到石英基板20的背面的加工。

[0049] 《Second protective film formation process S4》《第2保护膜形成工序S4》

[0050] 如 Figure 8 As shown, a second protective film 6 is formed on the metal film M2. The film formation method of the second protective film 6 is the same as that of the first protective film 5 described above. The second protective film 6 has openings 61, 62, and 63 in the portions of the quartz substrate 20 to be removed. Among them, the opening 61 overlaps with the second groove formation region Q6 where the second grooves 222 and 232 are formed. The opening 62 overlaps with the inter-arm region Q4. The opening 63 overlaps with the inter-element region Q5.如

[0051] 《Second dry etching process S5》《第2干蚀刻工序S5》

[0052] 如 Figure 9As shown, dry etching is performed on the quartz substrate 20 from the second surface 2B side隔着第2保护膜6, and the second grooves 222 and 232 and the outer shape of the vibrating substrate 2 are simultaneously formed on the second surface 2B. This process is carried out in the same manner as the first dry etching process S3.

[0053] This process ends when the second grooves 222 and 232 reach the desired depth. In the present embodiment, the width W in the X-axis direction of the second grooves 222 and 232 is compared with the width A in the X-axis direction of the inter-arm region Q4, and W < A. Additionally, when the width W is compared with the width B in the X-axis direction of the inter-element region Q5, W < B. Therefore, due to the microloading effect, the etching rate of the second groove formation region Q6 is lower than the etching rates of the inter-arm region Q4 and the inter-element region Q5. As a result, the depth Wa of the second grooves 222 and 232 is shallower than the depths Aa and Ba of the outer shape of the vibrating substrate 2. That is, Wa < Aa (Wa / Aa < 1), Wa < Ba (Wa / Ba < 1). Moreover, the depths Aa and Ba are each more than half of the thickness of the quartz substrate 20. That is, Aa ≥ 0.5Ta, Ba ≥ 0.5Ta. Therefore, the inter-arm region Q4 and the inter-element region Q5 are each penetrated.

[0054] As Figure 10 shown, after this process is completed, the second protective film 6 and the metal film M2 are removed. Thereby, a plurality of vibrating substrates 2 are formed together from the quartz substrate 20.

[0055] 《Electrode Formation Process S6》

[0056] A metal film is formed on the front surface of the vibrating substrate 2, and this metal film is patterned to form the electrodes 3.

[0057] Thereby, the vibrating element 1 is obtained. As described above, by dry etching, processing can be performed without being affected by the crystal plane of quartz, and thus, excellent dimensional accuracy can be achieved. Additionally, by simultaneously forming the first grooves 221 and 231, the second grooves 222 and 232, and the outer shape of the vibrating substrate 2, reduction of the manufacturing process of the vibrating element 1 and cost reduction of the vibrating element 1 can be realized. Moreover, positional deviation of the first grooves 221 and 231 and the second grooves 222 and 232 with respect to the outer shape is prevented, and the formation accuracy of the vibrating substrate 2 is improved.

[0058] The manufacturing method of the vibrating element 1 has been described above. Next, the conditions for more reliably manifesting the microloading effect will be described. Figure 11 The relationship between W / A and Wa / Aa when the etching time is different is shown. From this figure, it can be seen that the microloading effect is significantly manifested in the region where W / A ≤ 40% for each time.

[0059] In addition, the microloading effect also varies depending on the type of reaction gas used in dry etching. Figure 12 The relationship between W / A and Wa / Aa is shown when three different common reactive gases are used.

[0060] For example, if a fluorine-based gas containing a high carbon content, such as C2F4, C2F6, C3F6, or C4F8, is used as the reactant, a thicker sidewall protective film can be obtained, and the slope becomes smaller, as seen in gas type G3. Therefore, it is easy to increase Wa / Aa by making the shape with a smaller width A relative to the width W, which allows for miniaturization of the vibrating element 1. For example, when designing the frequency and CI value, sometimes a width W of a certain degree and a depth Wa close to the depth Aa are required. In this case, to miniaturize the vibrating element 1, it is necessary to reduce the width A; in this situation, at least one of C2F4, C2F6, C3F6, or C4F8 is particularly effective.

[0061] On the other hand, when fluorinated gases such as SF6 and CF4, which have low or no carbon content, are used alone or in combination with fluorinated gases with higher carbon content, the sidewall protective film becomes thinner, and the slope becomes greater, as in gas type G1. Therefore, it is possible to maintain a larger depth Wa relative to depth Aa and increase the width A relative to width W. For example, at least one of SF6 and CF4 is particularly effective when it is desired to increase the depth Wa, reduce the width of the first vibrating arm 22 and the second vibrating arm 23, and increase the width A.

[0062] When W / A = x and Wa / Aa = y, gas type G1 is represented by the following formula (1), gas type G2 is represented by the following formula (2), and gas type G3 is represented by the following formula (3).

[0063] y = -4.53 × 10 -6 x 4 +3.99×10 -4 x 3 -1.29×10 -3 x 2 +1.83×10 -1 x…(1)

[0064] y = -5.59 × 10 -8 x 4 +1.48×10 -5 x 3 -1.43×10 -3 x 2 +6.09×10 -2 x…(2)

[0065] y = -6.90 × 10 -10 x 4 +5.47×10 -7 x 3 -1.59×10-4 x 2 +2.03×10 -2 x…(3)

[0066] like Figure 12 As shown, if y lies in region P between equations (1) and (3), that is, if y satisfies equations (4) and (5) below, then the micro-load effect can be more reliably manifested using a general reactive gas. Therefore, the manufacturing of the vibrating element 1 becomes easier, and its manufacturing cost can be reduced.

[0067] y≥-4.53×10 -6 x 4 +3.99×10 -4 x 3 -1.29×10 -3 x 2 +1.83×10 -1 x…(4)

[0068] y≤-6.90×10 -10 x 4 +5.47×10 -7 x 3 -1.59×10 -4 x 2 +2.03×10 -2 x…(5)

[0069] When y does not satisfy equation (4), the change in depth Wa relative to the change in width W may become larger, resulting in a deviation in depth Wa. This situation can be suppressed by making y satisfy equation (4). Furthermore, when y does not satisfy equation (5), it is difficult to increase y in regions where x is large, leading to a shallower depth Wa. Alternatively, to increase depth Wa, it is necessary to approach W = A, which can easily create shape limitations. This situation can be suppressed by making y satisfy equation (5).

[0070] Here, for example, when the width W and depth Wa are set constant, if gas type G2 is selected, the width A can be reduced compared to gas type G1, and miniaturization of the vibrating element 1 can be achieved. When gas type G3 is selected, the width A can be further reduced compared to gas type G2, and further miniaturization of the vibrating element 1 can be achieved. Thus, from the viewpoint of miniaturization, in region P, it is further preferred that y is located in region PP between equations (2) and (3). That is, it is preferred that y satisfies equation (6) below and equation (5) above.

[0071] y≥-5.59×10 -8 x 4 +1.48×10 -5 x 3 -1.43×10-3 x 2 +6.09×10 -2 x…(6)

[0072] Figure 13 The diagram illustrates the improvement in the CI value of the vibrating element 1 when the first grooves 221 and 231 and the second grooves 222 and 232 are formed. According to the diagram, Wa / Aa ≥ 0.2 is preferred. Furthermore, in this embodiment, Wa / Aa < 1 is used to utilize the micro-load effect. Therefore, compared to the case where the first grooves 221 and 231 and the second grooves 222 and 232 are not formed, the CI value can be reduced to 30% or less. Thus, a vibrating element 1 with excellent vibration characteristics can be manufactured. Moreover, Wa / Aa ≥ 0.4 is preferred, thereby reducing the CI value to 10% or less compared to the case where the first grooves 221 and 231 and the second grooves 222 and 232 are not formed.

[0073] The manufacturing method of the vibrating element 1 has been described above. As described above, in the manufacturing method of the vibrating element 1, the vibrating element 1 has: a base 21; and a first vibrating arm 22 and a second vibrating arm 23, which extend from the base 21 along the Y-axis direction, which is a first direction, and are arranged along the X-axis direction, which is a second direction, which intersects the first direction. The first vibrating arm 22 and the second vibrating arm 23 each have: a first surface 2A and a second surface 2B arranged in opposite directions along the Z-axis direction, which intersects the Y-axis direction and the X-axis direction; a first groove 221 and 231 with a bottom opening on the first surface 2A; and a second groove 222 and 232 with a bottom opening on the second surface 2B. The manufacturing method includes: a preparation step S1, preparing a quartz substrate 20 having a first surface 2A and a second surface 2B; and a first protective film forming step S2, forming a first groove forming region Q on the first surface 2A of the quartz substrate 20, except for the first groove forming region Q of the first groove 221 and 231. 1. A first protective film 5 is formed outside the arm-to-arm region Q4 located between the first vibrating arm forming region Q2 forming the first vibrating arm 22 and the second vibrating arm forming region Q3 forming the second vibrating arm 23; 2. A first dry etching process S3 is performed, in which the quartz substrate 20 is dry-etched from the first surface 2A side through the first protective film 5, forming the first grooves 221, 231 and the outlines of the first vibrating arm 22 and the second vibrating arm 23 on the first surface 2A; 3. A second protective film forming process S4 is performed, in which a second protective film 6 is formed on the second surface 2B of the quartz substrate 20, except for the second groove forming region Q6 forming the second grooves 222, 232 and the arm-to-arm region Q4; 4. A second dry etching process S5 is performed, in which the quartz substrate 20 is dry-etched from the second surface 2B side through the second protective film 6, forming the second grooves 222, 232 and the outlines of the first vibrating arm 22 and the second vibrating arm 23 on the second surface 2B. When the depths of the first grooves 221 and 231 formed in the first dry etching process S3 and the depths of the second grooves 222 and 232 formed in the second dry etching process S5 are Wa, and the depths of the outer shape formed in the first dry etching process S3 and the outer shape formed in the second dry etching process S5 are Aa, Wa / Aa < 1 is satisfied in at least one of the first dry etching process S3 and the second dry etching process S5. According to this manufacturing method, the first grooves 221 and 231, the second grooves 222 and 232, and the outer shape of the vibrating substrate 2 can be formed simultaneously. Therefore, it is possible to reduce the number of manufacturing steps for the vibrating element 1 and lower the cost of the vibrating element 1. Furthermore, by preventing positional misalignment of the first grooves 221 and 231 and the second grooves 222 and 232 relative to the outer shape, the forming accuracy of the vibrating substrate 2 is improved.

[0074] Furthermore, as described above, in the manufacturing method of the vibrating element 1, it is preferable to satisfy Wa / Aa ≥ 0.2. Therefore, compared to the case where the first grooves 221 and 231 and the second grooves 222 and 232 are not formed, the CI value can be reduced to less than 30%. Thus, it is possible to manufacture a vibrating element 1 with excellent vibration characteristics.

[0075] Furthermore, as described above, in the manufacturing method of the vibrating element 1, if the width of the first grooves 221, 231 and the second grooves 222, 232 along the X-axis is W, the width of the inter-arm region Q4 along the X-axis is A, and W / A = x and Wa / Aa = y, then equation (4) is preferably satisfied. This allows for more reliable manifestation of the micro-load effect using a common reactive gas. Therefore, the manufacturing of the vibrating element 1 becomes easier, and its manufacturing cost can be reduced. If y does not satisfy equation (4), the change in depth Wa relative to the change in width W may increase, and the depth Wa may deviate. This situation can be suppressed by making y satisfy equation (4).

[0076] Furthermore, as described above, in the manufacturing method of the vibrating element 1, it is preferable to satisfy the above equation (5). This allows for a more reliable manifestation of the micro-load effect using a common reactive gas. Consequently, the manufacturing of the vibrating element 1 becomes easier, and its manufacturing cost can be reduced. Additionally, if y does not satisfy equation (5), it is difficult to increase y in regions where x is large, and the depth Wa becomes shallower. Alternatively, to increase the depth Wa, it is necessary to approach W=A, which easily leads to shape limitations. By making y satisfy equation (5), this situation can be suppressed.

[0077] Furthermore, as described above, in the manufacturing method of the vibrating element 1, at least one of C2F4, C2F6, C3F6, and C4F8 is preferably used as the reactant gas in the first dry etching step S3 and the second dry etching step S5. This allows for a larger Wa / Aa ratio, with a width A smaller than a width W, thus enabling miniaturization of the vibrating element 1.

[0078] Furthermore, as described above, in the manufacturing method of the vibrating element 1, at least one of CF4 and SF6 is preferably used as the reactant gas in the first dry etching step S3 and the second dry etching step S5. This allows the depth Wa to be kept relatively large relative to the depth Aa, and the width A to be increased relative to the width W. Therefore, for example, it is possible to increase the depth Wa while simultaneously reducing the width of the first vibrating arm 22 and the second vibrating arm 23 and increasing the width A.

[0079] The manufacturing method of the vibration element of the present invention has been described above based on the illustrated embodiments. However, the present invention is not limited thereto, and the structure of each part can be replaced with any structure having the same function. Furthermore, other arbitrary components may be added to the present invention. Additionally, the various embodiments may be appropriately combined.

[0080] For example, in the above embodiment, Wa / Aa<1 is satisfied in the first dry etching step S3 and the second dry etching step S5, but it is not limited to this, as long as Wa / Aa<1 is satisfied in at least one of them.

[0081] Furthermore, the vibrating element manufactured using the method of the present invention is not particularly limited; for example, it can be... Figure 14 and Figure 15 The vibrating element 1A is shown. In the vibrating element 1A, a pair of first grooves 221 are arranged along the X-axis direction on the first surface 2A of the first vibrating arm 22, and a pair of second grooves 222 are arranged along the X-axis direction on the second surface 2B. Similarly, a pair of first grooves 231 are arranged along the X-axis direction on the first surface 2A of the second vibrating arm 23, and a pair of second grooves 232 are arranged along the X-axis direction on the second surface 2B. Furthermore, in this structure, due to the arrangement of multiple grooves, the width W of each groove can easily become thinner. Therefore, in the first dry etching step S3 and the second dry etching step S5, at least one of SF6 and CF4 is preferably used as the reactive gas. This allows for deeper formation of each groove and reduces the CI value.

[0082] In addition, the vibrating element can also be Figure 16 and Figure 17 The double tuning fork type vibrating element 7 is shown. Additionally, in... Figure 16 and Figure 17 The electrodes are omitted from the diagram. The double tuning fork type vibrating element 7 has a pair of bases 711 and 712; and a first vibrating arm 72 and a second vibrating arm 73 connecting the bases 711 and 712. In addition, the first vibrating arm 72 and the second vibrating arm 73 have a bottomed first groove 721 and 731 that opens on the first surface 7A and a bottomed second groove 722 and 732 that opens on the second surface 7B.

[0083] Alternatively, for example, the vibrating element can also be Figures 18 to 20 The gyroscope oscillating element 8 is shown. Additionally, in... Figures 18 to 20The electrodes are omitted from the diagram. The gyroscope vibration element 8 includes: a base 81; a pair of detection vibration arms 82 and 83 extending from the base 81 in the Y-axis direction; a pair of connecting arms 84 and 85 extending from the base 81 in the X-axis direction; drive vibration arms 86 and 87 extending from the front end of the connecting arm 84 in the Y-axis direction; and drive vibration arms 88 and 89 extending from the front end of the connecting arm 85 in the Y-axis direction. In this gyroscope vibration element 8, when the drive vibration arms 86, 87, 88, and 89 are directed towards... Figure 18 When the angular velocity ωz about the Z-axis is applied under the bending vibration state in the direction of arrow SD, the detection vibration arms 82 and 83 are re-excited to bend in the direction of arrow SS by the Coriolis force, and the angular velocity ωz is detected based on the charge output from the detection vibration arms 82 and 83 through this bending vibration.

[0084] Furthermore, the detection vibration arms 82 and 83 have a first groove 821 and 831 with a bottom that opens on the first surface 8A, and a second groove 822 and 832 with a bottom that opens on the second surface 8B. Similarly, the drive vibration arms 86, 87, 88, and 89 have a first groove 861, 871, 881, and 891 with a bottom that opens on the first surface 8A, and a second groove 862, 872, 882, and 892 with a bottom that opens on the second surface 8B. In this gyro vibration element 8, for example, a pair of vibration arms adjacent in the X-axis direction, such as the detection vibration arm 82 and drive vibration arm 86, the detection vibration arm 82 and drive vibration arm 88, the detection vibration arm 83 and drive vibration arm 87, and the detection vibration arm 83 and drive vibration arm 89, can be designated as the first vibration arm and the second vibration arm.

[0085] Furthermore, in the case of the gyroscope oscillator 8, the inter-arm region Q4 needs to be increased structurally. In this case, the depth Wa becomes shallower in the region between equations (2) and (3) above, which may lead to a decrease in sensitivity. Therefore, it is preferable to use the region between equations (1) and (2) above.

[0086] Alternatively, for example, the vibrating element can also be Figures 21 to 23 The gyroscope vibration element 9 shown is described. The gyroscope vibration element 9 has: a base 91; a pair of drive vibration arms 92 and 93 extending from the base 91 towards the positive Y-axis direction and arranged in the X-axis direction; and a pair of detection vibration arms 94 and 95 extending from the base 91 towards the negative Y-axis direction and arranged in the X-axis direction. In this gyroscope vibration element 9, when the drive vibration arms 92 and 93 are moved towards the positive Y-axis direction... Figure 21 When the angular velocity ωy about the Y-axis is applied under the bending vibration state in the direction of arrow SD, the detection vibration arms 94 and 95 are re-excited to bend in the direction of arrow SS by the Coriolis force, and the angular velocity ωy is detected based on the charge output from the detection vibration arms 94 and 95 through this bending vibration.

[0087] Furthermore, the driving vibration arms 92 and 93 have a first groove 921 and 931 with a bottom that opens on the first surface 9A and a second groove 922 and 932 with a bottom that opens on the second surface 9B. Similarly, the detection vibration arms 94 and 95 have a first groove 941 and 951 with a bottom that opens on the first surface 9A and a second groove 942 and 952 with a bottom that opens on the second surface 9B. In this gyro vibration element 9, the driving vibration arms 92 and 93 or the detection vibration arms 94 and 95 serve as the first vibration arm and the second vibration arm, respectively.

Claims

1. A method for manufacturing a vibrating element, characterized in that, The vibrating element has: a base; and a first vibrating arm and a second vibrating arm, which extend from the base along a first direction and are arranged along a second direction intersecting the first direction. The first vibrating arm and the second vibrating arm each have: a first surface and a second surface arranged in opposite directions in a third direction that intersects the first direction and the second direction; and a first groove with a bottom that opens in the first surface; And the second groove with a bottom that opens on the second surface, The manufacturing method includes: Preparation process: Prepare a quartz substrate having the first surface and the second surface; In the first protective film forming process, a first protective film is formed on the first surface of the quartz substrate, except for the first groove forming region where the first groove is formed and the inter-arm region located between the first vibration arm forming region where the first vibration arm is formed and the second vibration arm forming region where the second vibration arm is formed. In the first dry etching process, the quartz substrate is dry etched from the first surface side through the first protective film to form the shape of the first groove, the first vibrating arm, and the second vibrating arm on the first surface. In the second protective film formation process, a second protective film is formed on the second surface of the quartz substrate, excluding the area where the second groove is formed and the inter-arm area; and In the second dry etching process, the quartz substrate is dry etched from the second surface side through the second protective film to form the outline of the second groove, the first vibrating arm, and the second vibrating arm on the second surface. Let the depth of the first groove formed in the first dry etching process and the depth of the second groove formed in the second dry etching process be Wa, and let the depth of the shape formed in the first dry etching process and the depth of the shape formed in the second dry etching process be Aa, In at least one of the first dry etching process and the second dry etching process, Wa / Aa < 1. Let W be the width of the first groove and the second groove along the second direction, and A be the width of the inter-arm region along the second direction. Let W / A = x and Wa / Aa = y. Satisfy the following formula: 。 2. The method for manufacturing a vibrating element according to claim 1, wherein, Satisfies Wa / Aa≥0.

2.

3. The method for manufacturing a vibrating element according to claim 1, wherein, Satisfy the following formula: 。 4. The method for manufacturing a vibrating element according to claim 1 or 2, wherein, In the first dry etching step and the second dry etching step, at least one of C2F4, C2F6, C3F6 and C4F8 is used as the reaction gas.

5. The method for manufacturing a vibrating element according to claim 1 or 2, wherein, In the first dry etching step and the second dry etching step, at least one of CF4 and SF6 is used as the reactive gas.

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