Tuning fork crystal oscillation sheet, manufacturing method and piezoelectric device

Abstract

The present application relates to the technical field of quartz tuning fork crystal resonator, and discloses a tuning fork crystal oscillation sheet, a preparation method and a piezoelectric device, wherein a base and a pair of vibration arms extending from the base are arranged, a second groove and a dispensing fixing block reserving a dispensing interval distance between the base and the root of the side of the base away from the vibration arms are formed at a first preset position and a second preset position of the base respectively, the transmission of vibration energy to the side of the base away from the vibration arms is inhibited, the influence of dispensing action on the root of the side of the base away from the vibration arms is avoided, meanwhile, a cross-section image is obtained by testing etching on a test quartz sheet interdigital sample, pixel-level classification and contour extraction calculation are used to remove the volume on the left and right and obtain the average etching offset, and the average etching offset is applied to the to-be-prepared quartz sheet interdigital sample, so that the left and right quality symmetry after the vibration arm groove is formed is ensured, and the overall impedance is reduced and the batch consistency and mass production efficiency are improved.

Description

Technical Field

[0001] This invention relates to the field of quartz tuning fork crystal resonator technology, and in particular to a tuning fork crystal oscillator, its preparation method, and a piezoelectric device. Background Technology

[0002] With the miniaturization and ultra-thinning of communication terminal electronic products, especially the stringent space requirements for circuit installation in smart wearable electronic products, electronic components also require smaller sizes and miniaturization. As a result, the package size of tuning fork quartz crystal resonators, which generate clock signals in electronic products, is gradually decreasing, which also means that the size of the tuning fork quartz oscillator is becoming smaller and smaller. Therefore, traditional machining processes are difficult to meet the requirements. To address this issue, QMEMS photolithography technology has been applied to the processing of anisotropic single-crystal SiO2 materials. With the miniaturization of quartz tuning fork crystal resonators, the biggest problem currently facing them is impedance, which typically includes the following two limitations: On one hand, after the tuning fork crystal is designed, it is fixed to the ceramic base with conductive adhesive, and then the base is vacuum-sealed. The design process typically involves studying the characteristics of the quartz crystal, focusing on the tuning fork's vibration amplitude, frequency, and corresponding vibration impedance. However, with the crystal ultimately fixed to the ceramic base, the kinetic energy of the arm beam is transferred along the arm beam to the area of ​​the fixed block, resulting in leakage vibration and excessive overall impedance of the tuning fork. Therefore, the method of fixing the tuning fork must be considered. If it is fixed at the base of the tuning fork, the conductive adhesive dots will dampen the tuning fork, causing excessive impedance.

[0003] On the other hand, quartz crystals exhibit significant anisotropy, with etching rates and sidewall evolution varying with crystal orientation. When etching the upper and lower surfaces of the vibrating arm at the nominal center, even if the etching window is located at the geometric center, the resulting grooves may still exhibit asymmetrical sidewall expansion, bottom skewness, or equivalent center offset, leading to different material removal amounts on the left and right sides of the vibrating arm and resulting in left-right mass asymmetry. Especially under mass production conditions with the same raw material batch, factors such as slight crystal orientation deviations and temperature / concentration fluctuations can amplify this asymmetry, making it difficult to simultaneously achieve processing efficiency and consistency by simply relying on experience-based settings or repeated trial etching of individual parts.

[0004] Therefore, how to change the design of quartz tuning fork resonators in existing technologies from a fixed perspective, improve the influence of adhesive dots on tuning fork vibration, thereby reducing the impedance of the tuning fork, and considering the anisotropy of quartz crystals, to improve production line efficiency and overall efficiency in the mass production stage is a technical problem that urgently needs to be solved. Summary of the Invention

[0005] This invention provides a tuning fork crystal oscillator, a preparation method, and a piezoelectric device, aiming to solve at least one of the above-mentioned technical problems.

[0006] To achieve the above objectives, the present invention provides a method for preparing a tuning fork crystal oscillator, comprising the following steps: S1: Provide test quartz wafer interdigitated finger samples and quartz wafer interdigitated finger samples to be prepared; wherein, the test quartz wafer interdigitated finger samples and the quartz wafer interdigitated finger samples to be prepared are configured as having a plurality of standard quartz wafer interdigitated fingers from the same raw material batch, each standard quartz wafer interdigitated finger including a base and a pair of vibrating arms extending from the base. S2: In the test of quartz wafer interdigitated samples, for each standard quartz wafer interdigitated finger, an etched window pattern for forming a first groove is provided on the vibrating arm; wherein the etched window pattern of the first groove has a nominal center position; S3: In the test quartz interdigitated sample, for each standard quartz interdigitated finger, test etching is performed on the upper and lower surfaces corresponding to the nominal center position to obtain the first groove; S4: Obtain the cross-sectional image data of the first groove, perform pixel-level region classification, contour extraction of the groove sidewall and bottom boundary, and extraction of the left and right outer boundaries of the vibrating arm beam region, calculate the removal volume on the left and right sides of the beam centerline and solve the average etching offset. S5: In the quartz sheet forked finger sample to be prepared, for each standard quartz sheet forked finger, a second groove and a dispensing fixing block with a pre-reserved dispensing interval distance between the first preset position and the second preset position of the base and the root of the base away from the vibrating arm are formed respectively. S6: In the quartz interdigitated sample to be prepared, for each standard quartz interdigitated finger, based on the nominal center position and the average etching offset, the actual etching position is determined, and an etching window pattern for forming a third groove is set on the vibrating arm; wherein, the etching window pattern of the third groove has the actual etching position. S7: In the quartz interdigitated sample to be prepared, for each standard quartz interdigitated finger, test etching is performed on the upper and lower surfaces corresponding to the actual etching position to obtain the third groove and obtain the final tuning fork crystal oscillator.

[0007] Optionally, the nominal center position is configured as a first etched area along the centerline of the vibration arm on the upper and lower surfaces of each vibration arm, and the actual etched position is a second etched area on the upper and lower surfaces of each vibration arm after being translated by an average etch offset along the centerline of the vibration arm in a direction perpendicular to the vibration arm.

[0008] Optionally, step S4: Obtain the cross-sectional image data of the first groove, perform pixel-level region classification, contour extraction of the groove sidewall and bottom boundary, and extraction of the left and right outer boundaries of the vibrating arm beam region, calculate the removal volume on the left and right sides of the beam centerline, and solve for the average etching offset, specifically including: S41: Obtain cross-sectional image data of the first groove; wherein, the cross-sectional image data includes at least the cross-sectional contours of the first groove region and the vibrating arm beam region; S42: Perform image processing on each cross-sectional image data, including pixel-level region classification, contour extraction of the groove sidewalls and bottom boundaries, and extraction of the left and right outer boundaries of the vibrating arm beam region, to determine the centerline of the arm beam; S43: Using the centerline of the arm beam as the boundary, construct a material removal area mask caused by the first groove in the cross-sectional image data, and calculate the removal volume on the left side of the centerline of the arm beam and the removal volume on the right side of the centerline of the arm beam respectively to obtain the difference in removal quality between the left and right sides. S44: Calculate the average etch offset based on the left-right quality difference removed from each cross-sectional image data; The average etching offset is used to offset the groove etching window relative to the center line of the arm beam along the width direction of the tuning fork arm during the formal etching, so that the left and right mass difference after the groove is formed by formal etching is minimized or less than the preset mass difference threshold.

[0009] Optionally, the cross-sectional image data is configured to include multiple cross-sectional image data along the direction of the vibrating arm, and the calculation of the removal volume located to the left of the centerline of the arm beam and the removal volume located to the right of the centerline of the arm beam is obtained by discretely integrating the left and right removal cross-sectional areas corresponding to the multiple cross-sections along the length direction of the tuning fork arm.

[0010] Optionally, step S42: Perform image processing on each cross-sectional image data, including pixel-level region classification, contour extraction of the groove sidewalls and bottom boundaries, and extraction of the left and right outer boundaries of the vibrating arm beam region, to determine the centerline of the beam, specifically including: S421: Perform preprocessing on each cross-sectional image data; wherein the preprocessing includes at least one or more of the following combinations: distortion correction, noise reduction filtering, brightness and contrast normalization; S422: Perform pixel-level region classification on each preprocessed cross-sectional image data, output the groove removal region probability map and the arm beam region probability map, and generate groove removal region masks and arm beam region masks for the upper and lower surfaces based on the threshold. S423: Perform connected component filtering and morphological processing on the groove removal region mask and the arm beam region mask; wherein, the morphological processing includes a combination of at least one or more of the following: opening operation, closing operation and hole filling; S424: Extract the left and right outer boundaries of the arm beam region based on the arm beam region mask, pair the left and right outer boundaries in the thickness direction to find the median value, obtain the arm beam centerline, and average the discrete sampling points in the thickness direction to obtain the arm beam centerline position corresponding to the cross section. The expression for the centerline of the arm beam is specifically as follows: ; In the formula, This represents the horizontal coordinate of the centerline at the thickness position z. This represents the lateral coordinates of the left / right outer boundaries of the arm beam at the thickness coordinate z. The expression for the position of the arm beam centerline is as follows: ; In the formula, This indicates the position of the centerline of the arm beam used to divide the left and right sides. This represents discrete sampling points along the thickness direction. Indicates the number of discrete sampling points; S425: Perform contour extraction on the boundary of the mask of the groove removal area to obtain the contour point set of the groove sidewall boundary and bottom boundary, and output the groove contour through curve fitting.

[0011] Optionally, step S43: Using the centerline of the arm beam as the boundary, construct a material removal area mask caused by the first groove in the cross-sectional image data, and calculate the removal volume located to the left of the centerline of the arm beam and the removal volume located to the right of the centerline of the arm beam respectively to obtain the left and right removal quality difference, specifically including: S431: Based on the position of the groove removal area mask and the centerline of the arm beam, the groove removal area is divided into a left removal area and a right removal area, and the left removal cross-sectional area and the right removal cross-sectional area corresponding to each cross-sectional image are calculated respectively. S432: Perform discrete integration along the vibrating arm direction on the left and right removal cross-sectional areas corresponding to multiple sections to obtain the left removal volume and the right removal volume; S433: Convert the removal volume to removal mass based on the quartz density, obtain the removal mass on the left and the removal mass on the right, and calculate the difference between the left and right removal masses; S434: Calculate the left and right removal quality differences corresponding to the upper surface and the lower surface respectively, and sum them to obtain the final left and right removal quality difference.

[0012] Optionally, step S44: Calculate the average etch offset based on the left-right removal quality difference of each cross-sectional image data, specifically including: S441: Define the etching offset as the amount of translation of the groove etching window relative to the centerline of the arm beam in a direction perpendicular to the vibrating arm during the actual etching process, and establish a first-order approximate model of the final left and right removal quality difference with respect to the etching offset. The expression for the first-order approximation model is specifically as follows: ; In the formula, Indicates the etching offset as The final removal of the left and right sides of the time is of poor quality. The difference in final left and right removal quality obtained from the etching test at the nominal center position indicates the difference in removal quality between the two sides. Indicates the etching offset. This indicates the sensitivity of the final left and right removal quality difference to the offset. S442: Calculate the final left and right removal quality difference corresponding to the two sets of candidate offsets, and estimate the sensitivity by differential method; wherein, the quality difference between the two sets of candidate offsets is obtained by performing an equivalent geometric translation on the mask of the groove removal area and repeatedly performing the calculation to obtain the left and right removal quality difference; The expression for estimating sensitivity using the difference method is specifically as follows: ; In the formula, , This represents two sets of candidate offsets. , Indicates two sets of candidate offsets , The corresponding final removal of the quality difference between the left and right sides; S443: Calculate the etching offset corresponding to the interdigitation finger of a single standard quartz sheet with the goal of zero mass difference between the left and right sides after formal etching. The expression for calculating the etching offset corresponding to a single standard quartz crystal interdigitator is as follows: ; In the formula, This indicates the final left-right removal quality difference obtained from the etching test at the nominal center position. S444: The average etching offset is calculated by summing and averaging the etching offsets of several standard quartz interdigitated fingers included in the quartz interdigitated sample to be prepared.

[0013] Optionally, step S5: In the quartz interdigitated sample to be prepared, for each standard quartz interdigitated finger, a second groove and a dispensing fixing block with a pre-reserved dispensing interval distance between the first preset position and the second preset position on the base are formed respectively, specifically including: S51: In the quartz interdigitated sample to be prepared, for each standard quartz interdigitated finger, a second groove corresponding to each vibrating arm is etched at the first preset position on the base; The first preset position is configured as any position in the vibration transmission path of the two vibrating arms along the opposite direction of extension, from the side of the base close to the vibrating arm to the side away from the vibrating arm, so as to suppress the transmission of vibration energy to the side of the base away from the vibrating arm. S52: In the quartz sheet interdigitated sample to be prepared, for each standard quartz sheet interdigitated finger, at the second preset position of the base, a dispensing fixing block corresponding to each vibrating arm is formed respectively; The second preset position is configured as any position between the two vibrating arms extending in the opposite direction from the second groove to the base on the side away from the vibrating arm, and a dispensing interval distance is reserved between the second preset position and the root of the base on the side away from the vibrating arm, so as to avoid the dispensing action affecting the root of the base on the side away from the vibrating arm. The adhesive fixing block also has an extension protrusion extending beyond both sides of the base along the direction perpendicular to the extension of the vibrating arm, in order to limit the installation of the tuning fork crystal oscillator.

[0014] Furthermore, to achieve the above objectives, the present invention also provides a tuning fork crystal oscillator, prepared using the tuning fork crystal oscillator preparation method described in any one of the above claims, comprising: A base and a pair of vibrating arms extending from the base; Wherein, the first preset position and the second preset position of the base respectively form a second groove and a dispensing fixing block with a reserved dispensing interval distance between the base and the root of the side away from the vibrating arm; The vibrating arm has a third groove formed at the actual etching position. The actual etching position is configured to be the etching position determined by the average etching offset of the test etching solution of the nominal center position for each standard quartz interdigitated finger in the test quartz interdigitated finger sample and the nominal center position.

[0015] In addition, to achieve the above objectives, the present invention also provides a piezoelectric device, comprising a tuning fork crystal oscillator prepared by the tuning fork crystal oscillator preparation method as described in any one of the above claims, or comprising a tuning fork crystal oscillator as described above.

[0016] The beneficial effects of this invention are as follows: It proposes a tuning fork crystal oscillator, a preparation method, and a piezoelectric device. By setting a base and a pair of vibrating arms extending from the base, a second groove is formed at a first preset position and a second preset position on the base, respectively, and a dispensing fixing block with a pre-reserved dispensing interval distance is formed between the base and the root of the base away from the vibrating arms. This suppresses the transmission of vibration energy to the side of the base away from the vibrating arms while avoiding the influence of the dispensing action on the root of the base away from the vibrating arms. At the same time, a cross-sectional image is obtained by test etching on the test quartz crystal interdigitated sample. The left and right volumes are calculated by pixel-level classification and contour extraction, and the average etching offset is obtained. This average etching offset is then applied to the quartz crystal interdigitated sample to be prepared, ensuring that the left and right masses are symmetrical after the vibration arm groove is formed, thereby reducing the overall impedance and improving batch consistency and mass production efficiency. Attached Figure Description

[0017] Figure 1 This is a schematic flowchart of the method for preparing a tuning fork crystal oscillator according to an embodiment of the present invention; Figure 2 This is a schematic diagram of the structure of the tuning fork crystal oscillator in an embodiment of the present invention; Figure 3 This is a schematic diagram of the finite element model of the traditional structure of the tuning fork crystal oscillator in Comparative Example 1; Figure 4 The diagram shows the principal harmonic response modes of the conventional structure of the tuning fork crystal oscillator in Comparative Example 1. Figure 5 The diagram shows the harmonic response amplitude-frequency characteristic of the conventional structure of the tuning fork crystal oscillator in Comparative Example 1. Figure 6 This is a schematic diagram of the finite element model of the structure in Example 1 where the fixed position of the tuning fork crystal oscillator is a certain distance from the root. Figure 7 The diagram shows the main resonant response modes of the structure with a fixed position of the tuning fork crystal oscillator at a certain distance from the root in Example 1. Figure 8 The diagram shows the harmonic response amplitude-frequency characteristic of the structure with a fixed position of the tuning fork crystal oscillator at a certain distance from the root in Example 1. Figure 9 This is a schematic diagram of the finite element model of the tuning fork crystal oscillator with the second groove structure in Comparative Example 2; Figure 10 The main resonant response modes of the tuning fork crystal oscillator with the second groove structure in Comparative Example 2 are shown. Figure 11 The diagram shows the amplitude-frequency response of the tuning fork crystal oscillator with the second groove structure in Comparative Example 2. Figure 12 This is a schematic diagram of the finite element model of the tuning fork crystal oscillator with a second groove structure and a designed adhesive area structure in Example 2; Figure 13 The main resonant response mode diagram of the tuning fork crystal oscillator with a second groove structure and a designed adhesive area structure in Example 2 is shown. Figure 14 The diagram shows the harmonic response amplitude-frequency characteristics of the tuning fork crystal oscillator with a second groove structure and a designed dispensing area structure in Example 2. Figure 15 This is a schematic diagram illustrating the asymmetry in the mass of the left and right arms of a tuning fork due to the anisotropy of the quartz crystal in the traditional method of preparing a tuning fork crystal oscillator. Figure 15 (a) is a structural diagram of the tuning fork crystal oscillator after etching. Figure 15 (b) is Figure 15 (a) is a cross-sectional view of the AA face of each arm beam.

[0018] Explanation of reference numerals in the attached figures: 1-Base; 2-Vibrating arm; 3-Second groove; 4-Third groove; 5-Dispensing fixing block. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0020] like Figure 1 As shown, this embodiment of the invention provides a method for preparing a tuning fork crystal oscillator, comprising the following steps: S1: Provide test quartz wafer interdigitated finger samples and quartz wafer interdigitated finger samples to be prepared; wherein, the test quartz wafer interdigitated finger samples and the quartz wafer interdigitated finger samples to be prepared are configured as having a plurality of standard quartz wafer interdigitated fingers from the same raw material batch, each standard quartz wafer interdigitated finger including a base and a pair of vibrating arms extending from the base. S2: In the test of quartz wafer interdigitated samples, for each standard quartz wafer interdigitated finger, an etched window pattern for forming a first groove is provided on the vibrating arm; wherein the etched window pattern of the first groove has a nominal center position; S3: In the test quartz interdigitated sample, for each standard quartz interdigitated finger, test etching is performed on the upper and lower surfaces corresponding to the nominal center position to obtain the first groove; S4: Obtain the cross-sectional image data of the first groove, perform pixel-level region classification, contour extraction of the groove sidewall and bottom boundary, and extraction of the left and right outer boundaries of the vibrating arm beam region, calculate the removal volume on the left and right sides of the beam centerline and solve the average etching offset. S5: In the quartz sheet forked finger sample to be prepared, for each standard quartz sheet forked finger, a second groove and a dispensing fixing block with a pre-reserved dispensing interval distance between the first preset position and the second preset position of the base and the root of the base away from the vibrating arm are formed respectively. S6: In the quartz interdigitated sample to be prepared, for each standard quartz interdigitated finger, based on the nominal center position and the average etching offset, the actual etching position is determined, and an etching window pattern for forming a third groove is set on the vibrating arm; wherein, the etching window pattern of the third groove has the actual etching position. S7: In the quartz interdigitated sample to be prepared, for each standard quartz interdigitated finger, test etching is performed on the upper and lower surfaces corresponding to the actual etching position to obtain the third groove and obtain the final tuning fork crystal oscillator.

[0021] It's important to note that with the miniaturization of quartz tuning fork crystal resonators, the biggest challenge currently faces is impedance, which typically involves two limitations: First, after the tuning fork crystal is designed, it's fixed to a ceramic substrate using conductive adhesive, and then the substrate is vacuum-sealed. The design process generally focuses on the characteristics of the quartz crystal, particularly the tuning fork's amplitude, frequency, and corresponding vibration impedance. However, with the crystal ultimately fixed to the ceramic substrate, the kinetic energy of the arm beam is transferred along the arm beam to the fixed area, resulting in leakage vibration and excessive overall impedance. Therefore, the fixing method must be considered. Fixing it at the root of the tuning fork will inevitably cause the conductive adhesive dots to dampen the tuning fork, leading to excessive impedance. Second, quartz crystals exhibit significant anisotropy; the etching rate and sidewall evolution vary with crystal orientation. When etching the upper and lower surfaces of the vibrating arm at the nominal center position, even if the etching window is located at the geometric center, the resulting groove may still exhibit asymmetrical sidewall expansion, bottom skewness, or equivalent center offset, resulting in different material removal amounts on the left and right sides of the vibrating arm and causing left-right mass asymmetry. Especially under mass production conditions of the same raw material batch, factors such as slight crystal orientation deviations and temperature and concentration fluctuations will amplify this asymmetry, making it difficult to simultaneously achieve processing efficiency and consistency by simply relying on experience settings or repeated trial etching of a single piece.

[0022] To address the aforementioned issues, this embodiment employs a base and a pair of vibrating arms extending from it. Second grooves are formed at first and second preset positions on the base, respectively, along with a dispensing fixing block with a pre-defined dispensing interval between the base and the root of the base on the side furthest from the vibrating arms. This suppresses the transmission of vibration energy to the side of the base furthest from the vibrating arms while avoiding the influence of the dispensing action on the root of the base on the side furthest from the vibrating arms. Simultaneously, a cross-sectional image is obtained by etching a test on a quartz interdigitated sample. Pixel-level classification and contour extraction are used to calculate the left and right removal volumes and obtain the average etching offset. This average etching offset is then applied to the quartz interdigitated sample to be prepared, ensuring symmetrical left and right mass after the vibrating arm grooves are formed. This reduces overall impedance and improves batch consistency and mass production efficiency.

[0023] In step S1, it is necessary to provide a test quartz interdigitated finger sample and a quartz interdigitated finger sample to be prepared, both of which come from the same raw material batch and contain several standard quartz interdigitated fingers.

[0024] In this embodiment of the invention, considering that the asymmetric trend of the groove caused by the anisotropy of quartz is related to the crystal orientation of the raw material, the distribution of impurities and the processing conditions, this embodiment uses standard quartz wafer interdigitated fingers from the same batch of raw materials to form test quartz wafer interdigitated finger samples and quartz wafer interdigitated finger samples to be prepared. The raw materials from the same batch are closer in terms of crystal orientation deviation and material constant. The offset compensation amount obtained by the test sample can be transferred to the sample to be prepared, thereby realizing the support of batch production with a small number of tests.

[0025] In step S2, an etched window pattern for forming a first groove is set on the vibrating arm of each standard interdigitated finger of the test quartz wafer interdigitated sample, having a nominal center position.

[0026] In this embodiment of the invention, the nominal center position can be defined as the geometric center in the width direction of the vibrating arm or the region where the centerline of the arm beam is located. This definition is not limited to a certain geometric configuration; for example, the window can be rectangular, strip-shaped, or a multi-segment combination window, as long as it can form a groove structure.

[0027] In a preferred embodiment, the nominal center position is configured as a first etched area along the centerline of the vibration arm on the upper and lower surfaces of each vibration arm, and the actual etched position is a second etched area on the upper and lower surfaces of each vibration arm after being translated by an average etch offset along the centerline of the vibration arm in a direction perpendicular to the vibration arm.

[0028] In step S3, test etching is performed on the upper and lower surfaces corresponding to the nominal center position to obtain the first groove.

[0029] In this embodiment of the invention, the significance of the nominal center test etching lies in enabling systematic asymmetric development. This asymmetry is not equivalent to alignment error, but rather the result of the combined effect of materials and processes. Therefore, it is necessary to infer the required offset from the morphology data to compensate for the difference in removal amounts between the left and right sides.

[0030] In a preferred embodiment, step S4: acquiring cross-sectional image data of the first groove, performing pixel-level region classification, contour extraction of the groove sidewalls and bottom boundaries, and extraction of the left and right outer boundaries of the vibrating arm beam region, calculating the removal volume on the left and right sides of the beam centerline, and solving for the average etching offset, specifically including: S41: Obtain cross-sectional image data of the first groove; wherein, the cross-sectional image data includes at least the cross-sectional contours of the first groove region and the vibrating arm beam region; S42: Perform image processing on each cross-sectional image data, including pixel-level region classification, contour extraction of the groove sidewalls and bottom boundaries, and extraction of the left and right outer boundaries of the vibrating arm beam region, to determine the centerline of the arm beam; S43: Using the centerline of the arm beam as the boundary, construct a material removal area mask caused by the first groove in the cross-sectional image data, and calculate the removal volume on the left side of the centerline of the arm beam and the removal volume on the right side of the centerline of the arm beam respectively to obtain the difference in removal quality between the left and right sides. S44: Calculate the average etch offset based on the left-right quality difference removed from each cross-sectional image data; The average etching offset is used to offset the groove etching window relative to the center line of the arm beam along the width direction of the tuning fork arm during the formal etching, so that the left and right mass difference after the groove is formed by formal etching is minimized or less than the preset mass difference threshold.

[0031] In practical applications, the cross-sectional image data is configured to include multiple cross-sectional image data along the direction of the vibrating arm. The calculation of the removal volume located to the left of the centerline of the arm beam and the removal volume located to the right of the centerline of the arm beam is obtained by discretely integrating the left and right removal cross-sectional areas corresponding to the multiple cross-sections along the length direction of the tuning fork arm.

[0032] Specifically, step S42: Perform image processing on each cross-sectional image data, including pixel-level region classification, contour extraction of the groove sidewalls and bottom boundaries, and extraction of the left and right outer boundaries of the vibrating arm beam region, to determine the centerline of the beam, specifically including: S421: Perform preprocessing on each cross-sectional image data; wherein the preprocessing includes at least one or more of the following combinations: distortion correction, noise reduction filtering, brightness and contrast normalization; S422: Perform pixel-level region classification on each preprocessed cross-sectional image data, output the groove removal region probability map and the arm beam region probability map, and generate groove removal region masks and arm beam region masks for the upper and lower surfaces based on the threshold. S423: Perform connected component filtering and morphological processing on the groove removal region mask and the arm beam region mask; wherein, the morphological processing includes a combination of at least one or more of the following: opening operation, closing operation and hole filling; S424: Extract the left and right outer boundaries of the arm beam region based on the arm beam region mask, pair the left and right outer boundaries in the thickness direction to find the median value, obtain the arm beam centerline, and average the discrete sampling points in the thickness direction to obtain the arm beam centerline position corresponding to the cross section. The expression for the centerline of the arm beam is specifically as follows: ; In the formula, This represents the horizontal coordinate of the centerline at the thickness position z. This represents the lateral coordinates of the left / right outer boundaries of the arm beam at the thickness coordinate z. The expression for the position of the arm beam centerline is as follows: ; In the formula, This indicates the position of the centerline of the arm beam used to divide the left and right sides. This represents discrete sampling points along the thickness direction. Indicates the number of discrete sampling points; S425: Perform contour extraction on the boundary of the mask of the groove removal area to obtain the contour point set of the groove sidewall boundary and bottom boundary, and output the groove contour through curve fitting.

[0033] In this embodiment of the invention, pixel-level region classification is performed on the cross-sectional image data to obtain a groove removal region mask and an arm beam region mask. Then, the left and right outer boundaries are extracted and the centerline is calculated. It should be noted that this embodiment uses the geometry of the arm beam itself to determine the left and right boundaries, avoiding error propagation caused by relying solely on the window center, and can also offset the apparent offset caused by differences in the posture of the cross-sectional sample.

[0034] Specifically, step S43: Using the centerline of the arm beam as the boundary, a material removal area mask caused by the first groove is constructed in the cross-sectional image data, and the removal volume located to the left of the centerline of the arm beam and the removal volume located to the right of the centerline of the arm beam are calculated respectively to obtain the difference in removal quality between the left and right sides, specifically including: S431: Based on the position of the groove removal area mask and the centerline of the arm beam, the groove removal area is divided into a left removal area and a right removal area, and the left removal cross-sectional area and the right removal cross-sectional area corresponding to each cross-sectional image are calculated respectively. S432: Perform discrete integration along the vibrating arm direction on the left and right removal cross-sectional areas corresponding to multiple sections to obtain the left removal volume and the right removal volume; S433: Convert the removal volume to removal mass based on the quartz density, obtain the removal mass on the left and the removal mass on the right, and calculate the difference between the left and right removal masses; S434: Calculate the left and right removal quality differences corresponding to the upper surface and the lower surface respectively, and sum them to obtain the final left and right removal quality difference.

[0035] In this embodiment of the invention, after obtaining the centerline of the arm beam, a material removal region mask caused by the groove is constructed in the cross-sectional image using the centerline as the boundary, and the removal volumes located to the left and right of the centerline are calculated respectively. When calculating the pixel area, the expressions for the left and right removal cross-sectional areas corresponding to the i-th cross-section are specifically as follows: ; ; In the formula, Represents pixel coordinates, This represents the binary mask representing the groove removal region of the i-th cross-section. Let represent the set of pixels located to the left of the midline in the i-th cross-sectional image. Let represent the set of pixels located to the right of the midline in the i-th cross-sectional image. This represents the left-removed cross-sectional area of ​​the i-th section. This represents the right-hand section area of ​​the i-th section. Indicates pixel size.

[0036] When the cross-sectional image data includes multiple cross-sectional images along the vibrating arm direction and the distance between adjacent cross-sections is Δy, discrete integration is performed on the left and right removed cross-sectional areas corresponding to the multiple cross-sections along the vibrating arm direction to obtain the expressions for the left and right removed volumes, specifically: ;

[0037] In the formula, This indicates the volume to be removed from the left and right sides, and m represents the number of cross-sectional images.

[0038] Then, convert the removed volume to removed mass and sum the results for both the upper and lower surfaces, resulting in: ; ; ; In the formula, Indicates the removal of mass on the left and right. This indicates the difference in removal quality between the left and right sides caused by the grooves on the upper and lower surfaces. This represents the total left-right mass difference after the upper and lower surfaces are superimposed.

[0039] Therefore, this embodiment of the invention reduces random errors in a single section and improves computational stability by expanding the two-dimensional cross-sectional information into a three-dimensional removed volume. Then, it transforms the topographic asymmetry into the difference in left and right removed mass, so that the optimization target directly corresponds to the root cause of device performance, which is left and right mass symmetry.

[0040] Specifically, step S44: Calculate the average etch offset based on the left-right removal quality difference of each cross-sectional image data, including: S441: Define the etching offset as the amount of translation of the groove etching window relative to the centerline of the arm beam in a direction perpendicular to the vibrating arm during the actual etching process, and establish a first-order approximate model of the final left and right removal quality difference with respect to the etching offset. The expression for the first-order approximation model is specifically as follows: ; In the formula, Indicates the etching offset as The final removal of the left and right sides of the time is of poor quality. The difference in final left and right removal quality obtained from the etching test at the nominal center position indicates the difference in removal quality between the two sides. Indicates the etching offset. This indicates the sensitivity of the final left and right removal quality difference to the offset. S442: Calculate the final left and right removal quality difference corresponding to the two sets of candidate offsets, and estimate the sensitivity by differential method; wherein, the quality difference between the two sets of candidate offsets is obtained by performing an equivalent geometric translation on the mask of the groove removal area and repeatedly performing the calculation to obtain the left and right removal quality difference; The expression for estimating sensitivity using the difference method is specifically as follows: ; In the formula, , This represents two sets of candidate offsets. , Indicates two sets of candidate offsets , The corresponding final removal of the quality difference between the left and right sides; S443: Calculate the etching offset corresponding to the interdigitation finger of a single standard quartz sheet with the goal of zero mass difference between the left and right sides after formal etching. The expression for calculating the etching offset corresponding to a single standard quartz crystal interdigitator is as follows: ; In the formula, This indicates the final left-right removal quality difference obtained from the etching test at the nominal center position. S444: The average etching offset is calculated by summing and averaging the etching offsets of several standard quartz interdigitated fingers included in the quartz interdigitated sample to be prepared.

[0041] In this embodiment of the invention, the quality difference is mapped to the length that should be offset using sensitivity, and then the average of multiple standard interdigitates in the same batch is calculated to obtain the average etching offset that can be used for the entire batch of samples to be prepared, thereby taking into account both consistency and production line efficiency.

[0042] In a preferred embodiment, step S5: In the quartz interdigitated sample to be prepared, for each standard quartz interdigitated finger, a second groove and a dispensing fixing block with a pre-reserved dispensing interval distance between the first preset position and the second preset position on the base are formed respectively, specifically including: S51: In the quartz interdigitated sample to be prepared, for each standard quartz interdigitated finger, a second groove corresponding to each vibrating arm is etched at the first preset position on the base; The first preset position is configured as any position in the vibration transmission path of the two vibrating arms along the opposite direction of extension, from the side of the base close to the vibrating arm to the side away from the vibrating arm, so as to suppress the transmission of vibration energy to the side of the base away from the vibrating arm. S52: In the quartz sheet interdigitated sample to be prepared, for each standard quartz sheet interdigitated finger, at the second preset position of the base, a dispensing fixing block corresponding to each vibrating arm is formed respectively; The second preset position is configured as any position between the two vibrating arms extending in the opposite direction from the second groove to the base on the side away from the vibrating arm, and a dispensing interval distance is reserved between the second preset position and the root of the base on the side away from the vibrating arm, so as to avoid the dispensing action affecting the root of the base on the side away from the vibrating arm. The adhesive fixing block also has an extension protrusion extending beyond both sides of the base along the direction perpendicular to the extension of the vibrating arm, in order to limit the installation of the tuning fork crystal oscillator.

[0043] In this embodiment of the invention, by forming a second groove at a first preset position and a second preset position at the base of each standard interdigital finger of the sample to be prepared, and by reserving a dispensing interval distance between the second groove and the root of the base away from the vibrating arm, the transmission of vibration energy to the base away from the vibrating arm is suppressed, while avoiding the influence of the dispensing action on the root of the base away from the vibrating arm.

[0044] In step S6, the third groove window is set at the actual etching position based on the average etching offset.

[0045] It should be noted that the actual etching position can be understood as the region after a lateral translation of δ along the direction perpendicular to the vibrating arm. This translation direction can be defined as the width direction of the vibrating arm according to the process clamping, and its specific relationship with the imaging coordinates or device coordinates is not limited.

[0046] In step S7, etching is performed on the upper and lower surfaces corresponding to the actual etching position to form a third groove, thus obtaining the final tuning fork crystal oscillator.

[0047] In this embodiment of the invention, after the groove window is offset by δ, the natural skewness caused by anisotropy and the window position compensation cancel each other out in a quality sense, thereby reducing the left and right removal quality difference after the third groove is formed, which ultimately results in a decrease in overall impedance and an improvement in batch consistency.

[0048] In another embodiment, such as Figure 2 As shown, the present invention also provides a tuning fork crystal oscillator, which is prepared by the tuning fork crystal oscillator preparation method described in any one of the above claims, comprising: A base 1 and a pair of vibrating arms 2 extending from the base; Wherein, the first preset position and the second preset position of the base 1 respectively form a second groove 3 and a dispensing fixing block 5 with a reserved dispensing interval distance between the base 1 and the root of the side away from the vibrating arm 2; The vibrating arm 2 has a third groove 4 formed at its actual etching position. The actual etching position is configured to be the etching position determined by the average etching offset of the test etching solution based on the nominal center position of each standard quartz interdigitated finger in the test quartz interdigitated sample.

[0049] The following section presents the optimized design and dimensional parameters of a tuning fork crystal oscillator based on embodiments of the present invention. Combined with the original design of a traditional tuning fork crystal oscillator and similar designs, simulations and analyses of the tuning fork crystal oscillator are performed, providing the following comparative examples and embodiments: Comparative Example 1: In traditional designs, the structures used are as follows: Figure 3 As shown, the current method of applying adhesive dots near the root for curing is to apply the adhesive. If the adhesive dots are designed to be large, it means that when the chip is placed on the adhesive dots, due to its own weight, it may overflow to the tail of the chip, resulting in the entire tail being cured and bonded.

[0050] When a wafer is excited by an alternating electric field, the vibrational energy is transmitted to the adhesive dots, causing the force of the cured adhesive dots to be reflected back, thus interfering with the vibration of the vibrating pair. For example... Figure 4 The resonant modes shown (unit: m) clearly show asymmetric vibration of the tuning fork arm from the perspective of its vibration modes.

[0051] Furthermore, from the perspective of charge-frequency harmonic response, the feedback of the root force causes the wave vibration to reflect back, leading to the generation of secondary vibrations, such as... Figure 5 As shown, it can be clearly seen that interference from secondary vibrations occurs around 32.6kHz. This situation will inevitably lead to a decrease in the starting amplitude of the main vibration and an increase in impedance.

[0052] Example 1: Therefore, this invention proposes, in order to reduce the impact of the root of the fixing block, to keep the glue application point a certain distance away from the root to prevent glue from overflowing and sticking to the root. Figure 6 As shown, this dispensing area ensures that the glue dots are fixed at a position not close to the root of the fixing block.

[0053] The corresponding finite element analysis modes and charge amplitude-frequency characteristics are as follows: Figure 7 and Figure 8 As shown. Figure 7 As shown (unit: m), the vibrations of the two corresponding tuning fork arms are relative to... Figure 4 The symmetry is improved to some extent, and the amplitude-frequency characteristics of its charge effectively suppress the interference of secondary vibrations.

[0054] Comparative Example 2: In actual production, many manufacturers etch two grooves on the fixing block near the root of the tuning fork arm to suppress the transmission of vibration from the tuning fork arm to the fixing block. For example... Figure 9 As shown. The corresponding vibration modes and the amplitude-frequency characteristics of the charge are respectively as follows: Figure 10 (Unit: m) and Figure 11 As shown, it can be clearly observed that regardless of the vibration symmetry of the tuning fork arm or the charge amplitude-frequency characteristics relative to... Figure 3 and Figure 6 Both have shown significant improvements, and this structure effectively suppresses the transmission of vibration to the fixed block.

[0055] Example 2: based on Figure 9 In this embodiment of the invention, a new dispensing method is employed to separate the adhesive dots from the fixing block by a certain distance, preventing the root of the fixing block from being affected by the curing of the adhesive dots. Simultaneously, the position of the adhesive dots is clearly defined. Furthermore, this embodiment of the invention features a left-right protrusion in the fixing area structure, providing a limiting function. Its structure is as follows: Figure 12 As shown.

[0056] Figure 12 The structure of the tuning fork relative to Figure 9 The dimensions are exactly the same; the only difference is the size of the adhesive application area on the fixing block. The corresponding resonant modes and charge amplitude-frequency characteristic curves are shown below. Figure 13 (Unit: m) and Figure 14 As shown. From Figure 13 and Figure 14 As shown, the two tuning fork arms vibrate in a very symmetrical manner, but their resonant charge amplitude-frequency characteristics are relatively... Figure 11 As shown, its amplitude increased more than sixfold. This means that the adhesive dispensing, with its grooves to suppress the transmission of vibrational energy, further reduces the impact of adhesive curing.

[0057] Example 3: Considering that quartz crystal is an anisotropic material, corrosion occurs on the sides of the tuning fork arms, resulting in non-perpendicular crystal edges, such as... Figure 15 As shown, Figure 15 (a) is a tuning fork crystal oscillator. Figure 15 (b) A cross-sectional view of the AA face of each arm of the tuning fork crystal oscillator after etching, showing the mass asymmetry that appears inside the tuning fork arm after etching. With this structure, the tuning fork arm vibrates left and right under the drive of an electric field. However, because the grooves on the entire tuning fork arm are etched, the center of the groove is at the center of the upper surface of the tuning fork arm. Due to the anisotropy of the etching, as... Figure 15 As shown in (b), the mass of the left and right arms of the same tuning fork is asymmetrical, which will inevitably lead to asymmetrical vibration. This effect will also inevitably increase the overall impedance of the tuning fork.

[0058] In this embodiment of the invention, to further improve the impedance problem, when etching the shape of the tuning fork, especially the position of the groove on the upper surface of the tuning fork arm, an offset is made according to the left-right mass symmetry, such as... Figure 15 As shown in (b), the offset between the nominal center position and the actual etch position is shown to compensate for the vibration asymmetry caused by the mass asymmetry of the left and right sides of the tuning fork. The offset is calculated based on the tuning fork crystal oscillator preparation method mentioned in the previous embodiment, that is, based on the average etch offset calculated by performing test etching of the nominal center position on each standard quartz fork finger in the test quartz fork finger sample and the etch position determined by the nominal center position.

[0059] To further verify the effectiveness of the above theoretical calculations, the embodiments of the present invention target... Figure 3 , Figure 5 , Figure 9 , Figure 12 The tuning fork crystal oscillator obtained after etching position offset as mentioned in Example 3 was physically verified. All tuning forks adopted the SMD3215 package specification, with a tuning fork arm length of 1.76mm, a tuning fork arm width of 0.14mm, a total tuning fork length of 2.29mm, a total tuning fork width of 0.399mm, and a fixing block length of 0.155mm and a width of 0.08mm. The corresponding impedance tests are shown in Table 1. Table 1: Impedance test results of different embodiments and comparative examples

[0060] Through simulation and analysis of the above embodiments and comparative examples, the embodiments of the present invention, by setting a base and a pair of vibrating arms extending from the base, form a second groove at a first preset position and a dispensing fixing block with a pre-reserved dispensing interval distance between the base and the root of the base away from the vibrating arm, respectively. This suppresses the transmission of vibration energy to the base away from the vibrating arm while avoiding the influence of the dispensing action on the root of the base away from the vibrating arm. At the same time, a cross-sectional image is obtained by test etching on the test quartz interdigitated sample. The left and right volumes are calculated by pixel-level classification and contour extraction, and the average etching offset is obtained. This average etching offset is then applied to the quartz interdigitated sample to be prepared, ensuring that the left and right masses are symmetrical after the groove of the vibrating arm is formed, thereby reducing the overall impedance and improving batch consistency and mass production efficiency.

[0061] In another embodiment, the present invention also provides a piezoelectric device comprising a tuning fork crystal oscillator prepared by the tuning fork crystal oscillator preparation method as described in any one of the above claims, or comprising a tuning fork crystal oscillator as described above.

[0062] Other embodiments or specific implementations of the piezoelectric device of the present invention can be referred to the above-described method embodiments, and will not be repeated here.

[0063] It is understood that in the description of this specification, references to terms such as "one embodiment," "another embodiment," "other embodiments," or "first embodiment to Nth embodiment," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0064] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or system that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or system. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or system that includes that element.

[0065] The above are merely preferred embodiments of the present invention and do not limit the scope of the patent. Any equivalent structural or procedural transformations made based on the description and drawings of the present invention, or direct or indirect applications in other related technical fields, are similarly included within the scope of patent protection of the present invention.

Claims

1. A method for preparing a tuning fork crystal oscillator, characterized in that, Includes the following steps: S1: Provide test quartz wafer interdigitated finger samples and quartz wafer interdigitated finger samples to be prepared; wherein, the test quartz wafer interdigitated finger samples and the quartz wafer interdigitated finger samples to be prepared are configured as having a plurality of standard quartz wafer interdigitated fingers from the same raw material batch, each standard quartz wafer interdigitated finger including a base and a pair of vibrating arms extending from the base. S2: In the test of quartz wafer interdigitated samples, for each standard quartz wafer interdigitated finger, an etched window pattern for forming a first groove is provided on the vibrating arm; wherein the etched window pattern of the first groove has a nominal center position; S3: In the test quartz interdigitated sample, for each standard quartz interdigitated finger, test etching is performed on the upper and lower surfaces corresponding to the nominal center position to obtain the first groove; S4: Obtain the cross-sectional image data of the first groove, perform pixel-level region classification, contour extraction of the groove sidewall and bottom boundary, and extraction of the left and right outer boundaries of the vibrating arm beam region, calculate the removal volume on the left and right sides of the beam centerline and solve the average etching offset. S5: In the quartz sheet forked finger sample to be prepared, for each standard quartz sheet forked finger, a second groove and a dispensing fixing block with a pre-reserved dispensing interval distance between the first preset position and the second preset position of the base and the root of the base away from the vibrating arm are formed respectively. S6: In the quartz interdigitated sample to be prepared, for each standard quartz interdigitated finger, based on the nominal center position and the average etching offset, the actual etching position is determined, and an etching window pattern for forming a third groove is set on the vibrating arm; wherein, the etching window pattern of the third groove has the actual etching position. S7: In the quartz interdigitated sample to be prepared, for each standard quartz interdigitated finger, test etching is performed on the upper and lower surfaces corresponding to the actual etching position to obtain the third groove and obtain the final tuning fork crystal oscillator.

2. The method for preparing a tuning fork crystal oscillator as described in claim 1, characterized in that, The nominal center position is configured as a first etched area along the centerline of the vibration arm on the upper and lower surfaces of each vibration arm, and the actual etched position is a second etched area on the upper and lower surfaces of each vibration arm after being translated by an average etch offset along the centerline of the vibration arm in a direction perpendicular to the vibration arm.

3. The method for preparing a tuning fork crystal oscillator as described in claim 1, characterized in that, Step S4: Obtain the cross-sectional image data of the first groove, perform pixel-level region classification, contour extraction of the groove sidewalls and bottom boundaries, and extraction of the left and right outer boundaries of the vibrating arm beam region, calculate the removal volume on the left and right sides of the beam centerline, and solve for the average etching offset. Specifically, this includes: S41: Obtain cross-sectional image data of the first groove; wherein, the cross-sectional image data includes at least the cross-sectional contours of the first groove region and the vibrating arm beam region; S42: Perform image processing on each cross-sectional image data, including pixel-level region classification, contour extraction of the groove sidewalls and bottom boundaries, and extraction of the left and right outer boundaries of the vibrating arm beam region, to determine the centerline of the arm beam; S43: Using the centerline of the arm beam as the boundary, construct a material removal area mask caused by the first groove in the cross-sectional image data, and calculate the removal volume on the left side of the centerline of the arm beam and the removal volume on the right side of the centerline of the arm beam respectively to obtain the difference in removal quality between the left and right sides. S44: Calculate the average etch offset based on the left-right quality difference removed from each cross-sectional image data; The average etching offset is used to offset the groove etching window relative to the center line of the arm beam along the width direction of the tuning fork arm during the formal etching, so that the left and right mass difference after the groove is formed by formal etching is minimized or less than the preset mass difference threshold.

4. The method for preparing a tuning fork crystal oscillator as described in claim 3, characterized in that, The cross-sectional image data is configured to include multiple cross-sectional image data along the direction of the vibrating arm. The calculation of the removal volume located to the left of the centerline of the arm beam and the removal volume located to the right of the centerline of the arm beam is obtained by discretely integrating the left and right removal cross-sectional areas corresponding to the multiple cross-sections along the length direction of the tuning fork arm.

5. The method for preparing a tuning fork crystal oscillator as described in claim 4, characterized in that, Step S42: Perform image processing on each cross-sectional image data, including pixel-level region classification, contour extraction of the groove sidewalls and bottom boundaries, and extraction of the left and right outer boundaries of the vibrating arm beam region, to determine the centerline of the beam, specifically including: S421: Perform preprocessing on each cross-sectional image data; wherein the preprocessing includes at least one or more of the following combinations: distortion correction, noise reduction filtering, brightness and contrast normalization; S422: Perform pixel-level region classification on each preprocessed cross-sectional image data, output the groove removal region probability map and the arm beam region probability map, and generate groove removal region masks and arm beam region masks for the upper and lower surfaces based on the threshold. S423: Perform connected component filtering and morphological processing on the groove removal region mask and the arm beam region mask; wherein, the morphological processing includes a combination of at least one or more of the following: opening operation, closing operation and hole filling; S424: Based on the mask of the arm beam region, extract the left and right outer boundaries of the arm beam region, pair the left and right outer boundaries in the thickness direction to find the median value, obtain the centerline of the arm beam, and average the discrete sampling points in the thickness direction to obtain the position of the centerline of the arm beam corresponding to the cross section. The expression for the centerline of the arm beam is specifically as follows: ； In the formula, This represents the horizontal coordinate of the centerline at the thickness position z. This represents the lateral coordinates of the left / right outer boundaries of the arm beam at the thickness coordinate z. The expression for the position of the arm beam centerline is as follows: ； In the formula, This indicates the position of the centerline of the arm beam used to divide the left and right sides. This represents discrete sampling points along the thickness direction. Indicates the number of discrete sampling points; S425: Perform contour extraction on the boundary of the mask of the groove removal area to obtain the contour point set of the groove sidewall boundary and bottom boundary, and output the groove contour through curve fitting.

6. The method for preparing a tuning fork crystal oscillator as described in claim 5, characterized in that, Step S43: Using the centerline of the arm beam as the boundary, construct a material removal area mask caused by the first groove in the cross-sectional image data, and calculate the removal volume located to the left of the centerline of the arm beam and the removal volume located to the right of the centerline of the arm beam respectively to obtain the left and right removal quality difference, specifically including: S431: Based on the position of the groove removal area mask and the centerline of the arm beam, the groove removal area is divided into a left removal area and a right removal area, and the left removal cross-sectional area and the right removal cross-sectional area corresponding to each cross-sectional image are calculated respectively. S432: Perform discrete integration along the vibrating arm direction on the left and right removal cross-sectional areas corresponding to multiple sections to obtain the left removal volume and the right removal volume; S433: Convert the removal volume to removal mass based on the quartz density, obtain the removal mass on the left and the removal mass on the right, and calculate the difference between the left and right removal masses; S434: Calculate the left and right removal quality differences corresponding to the upper surface and the lower surface respectively, and sum them to obtain the final left and right removal quality difference.

7. The method for preparing a tuning fork crystal oscillator as described in claim 6, characterized in that, Step S44: Calculate the average etching offset based on the left-right quality difference removed from each cross-sectional image data, specifically including: S441: Define the etching offset as the amount of translation of the groove etching window relative to the centerline of the arm beam in a direction perpendicular to the vibrating arm during the actual etching process, and establish a first-order approximate model of the final left and right removal quality difference with respect to the etching offset. The expression for the first-order approximation model is specifically as follows: ； In the formula, Indicates the etching offset as The final removal of the left and right sides of the time is of poor quality. The difference in final left and right removal quality obtained from the etching test at the nominal center position indicates the difference in removal quality between the two sides. Indicates the etching offset. This indicates the sensitivity of the final left and right removal quality difference to the offset. S442: Calculate the final left and right removal quality difference corresponding to the two sets of candidate offsets, and estimate the sensitivity by differential method; wherein, the quality difference between the two sets of candidate offsets is obtained by performing an equivalent geometric translation on the mask of the groove removal area and repeatedly performing the calculation to obtain the left and right removal quality difference; The expression for estimating sensitivity using the difference method is specifically as follows: ； In the formula, , This represents two sets of candidate offsets. , Indicates two sets of candidate offsets , The corresponding final removal of the quality difference between the left and right sides; S443: Calculate the etching offset corresponding to the interdigitation finger of a single standard quartz sheet with the goal of zero mass difference between the left and right sides after formal etching. The expression for calculating the etching offset corresponding to a single standard quartz crystal interdigitator is as follows: ； In the formula, This indicates the final left-right removal quality difference obtained from the etching test at the nominal center position. S444: The average etching offset is calculated by summing and averaging the etching offsets of several standard quartz interdigitated fingers included in the quartz interdigitated sample to be prepared.

8. The method for preparing a tuning fork crystal oscillator as described in claim 1, characterized in that, Step S5: In the quartz interdigitated sample to be prepared, for each standard quartz interdigitated finger, a second groove and a dispensing fixing block with a pre-reserved dispensing interval distance between the first and second preset positions on the base and the root on the side of the base away from the vibrating arm are formed respectively, specifically including: S51: In the quartz interdigitated sample to be prepared, for each standard quartz interdigitated finger, a second groove corresponding to each vibrating arm is etched at the first preset position on the base; The first preset position is configured as any position in the vibration transmission path of the two vibrating arms along the opposite direction of extension of the base from the side close to the vibrating arm to the side away from the vibrating arm, so as to suppress the transmission of vibration energy to the side of the base away from the vibrating arm. S52: In the quartz sheet interdigitated sample to be prepared, for each standard quartz sheet interdigitated finger, at the second preset position of the base, a dispensing fixing block corresponding to each vibrating arm is formed respectively; The second preset position is configured as any position between the two vibrating arms extending in the opposite direction from the second groove to the base on the side away from the vibrating arm, and a dispensing interval distance is reserved between the second preset position and the root of the base on the side away from the vibrating arm, so as to avoid the dispensing action affecting the root of the base on the side away from the vibrating arm. The adhesive fixing block also has an extension protrusion extending beyond both sides of the base along the direction perpendicular to the extension of the vibrating arm, in order to limit the installation of the tuning fork crystal oscillator.

9. A tuning fork crystal oscillator, characterized in that, The tuning fork crystal oscillator is prepared by the method described in any one of claims 1-8, comprising: A base and a pair of vibrating arms extending from the base; Wherein, the first preset position and the second preset position of the base respectively form a second groove and a dispensing fixing block with a reserved dispensing interval distance between the base and the root of the side away from the vibrating arm; The vibrating arm has a third groove formed at the actual etching position. The actual etching position is configured to be the etching position determined by the average etching offset of the test etching solution of the nominal center position of each standard quartz interdigitated finger in the test quartz interdigitated finger sample and the nominal center position.

10. A piezoelectric device, characterized in that, The tuning fork crystal oscillator prepared by the method described in any one of claims 1-8 above, or the tuning fork crystal oscillator as described in claim 9 above.

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