High-performance quartz vibrating beam accelerometer and preparation method thereof

Abstract

The embodiment of the invention discloses a high-performance quartz vibrating beam accelerometer and a preparation method, the high-performance quartz vibrating beam accelerometer comprises a stress amplification unit and a resonance unit, and the stress amplification unit comprises a first vibrating beam mounting groove and a second vibrating beam mounting groove. The resonance unit comprises a vibration beam, a first vibration beam mounting arm, a second vibration beam mounting arm, a first driving groove and a second driving groove, the first driving groove and the second driving groove are formed in the upper surface and the lower surface of the vibration beam respectively, and the first vibration beam mounting arm and the second vibration beam mounting arm are arranged at the two ends of the vibration beam; the first vibrating beam mounting arm and the second vibrating beam mounting arm are embedded in the first vibrating beam mounting groove and the second vibrating beam mounting groove respectively, so that the resonance unit is fixedly assembled on the stress amplification unit, the sensitivity of the quartz vibrating beam accelerometer can be improved, the distance between the positive electrode and the negative electrode can be shortened, and the electric field driving efficiency is improved.

Description

Technical Field

[0001] This disclosure relates to the field of quartz vibrating beam accelerometer manufacturing technology, and in particular to a high-performance quartz vibrating beam accelerometer and its preparation method. Background Technology

[0002] Quartz beam accelerometers, as precision inertial sensors, are widely used in high-precision inertial measurement fields due to their advantages such as high sensitivity, high stability, low power consumption, and strong anti-interference capabilities. Currently, quartz beam accelerometers are mainly divided into two categories: integrated quartz beam accelerometers and split-type quartz beam accelerometers. However, integrated quartz beam accelerometers require deep etching during manufacturing, which easily leads to significant surface roughness on the beam, resulting in a decrease in the accelerometer's sensitivity and quality factor. On the other hand, split-type quartz beam accelerometers, due to their inherent double-beam conjugate vibration mode and slotless structure design, are prone to insufficient sensitivity and poor driving efficiency, making them unsuitable for high-precision inertial measurement applications. Summary of the Invention

[0003] The following is an overview of the subject matter described in detail in this disclosure. This overview is not intended to limit the scope of the claims.

[0004] This disclosure provides a high-performance quartz vibrating beam accelerometer and its fabrication method, which not only improves the sensitivity of the quartz vibrating beam accelerometer and shortens the distance between the positive and negative electrodes, thereby improving the electric field driving efficiency, but also effectively suppresses the surface roughness degradation during the fabrication process of the quartz vibrating beam accelerometer, thereby improving the performance stability of the quartz vibrating beam accelerometer.

[0005] In a first aspect, embodiments of this disclosure provide a high-performance quartz vibrating beam accelerometer, including a stress amplification unit and a resonant unit. The stress amplification unit includes a first vibration beam mounting groove and a second vibration beam mounting groove. The resonant unit includes a vibration beam, a first vibration beam mounting arm, a second vibration beam mounting arm, a first drive groove, and a second drive groove. The first drive groove and the second drive groove are respectively disposed on the upper and lower surfaces of the vibration beam. The first vibration beam mounting arm and the second vibration beam mounting arm are disposed at both ends of the vibration beam. The first vibration beam mounting arm and the second vibration beam mounting arm are respectively embedded in the first vibration beam mounting groove and the second vibration beam mounting groove, so that the resonant unit is fixedly mounted on the stress amplification unit.

[0006] According to some embodiments of the first aspect of this application, the stress amplification unit further includes a U-shaped mass load block, a first flexible support beam, a second flexible support beam, an isolation frame, a first connecting portion, a second connecting portion, a base, a first mounting frame, and a second mounting frame.

[0007] According to some embodiments of the first aspect of this application, the first flexible support beam and the second flexible support beam extend symmetrically from the top of the base, and the free ends of the first flexible support beam and the second flexible support beam are fixedly connected to the U-shaped mass load block; the opening of the U-shaped mass load block faces the opening of the base, and the vibration beam is suspended between the U-shaped mass load block and the base, with both ends of the vibration beam connected to the bottom end of the opening of the U-shaped mass load block and the bottom end of the opening of the base, respectively.

[0008] According to some embodiments of the first aspect of this application, the bottom end of the base is connected to the inner side of the isolation frame via the first connecting portion, and the outer side of the isolation frame is connected to the first mounting frame and the second mounting frame via the second connecting portion, wherein the first mounting frame and the second mounting frame are symmetrically arranged.

[0009] According to some embodiments of the first aspect of this application, electrodes are provided on both the inner and outer sides of the first driving groove and the second driving groove. The polarity of the electrode inside the first groove and the electrode inside the second groove are the same, and the polarity of the electrode inside the first groove and the electrode inside the second groove are opposite to the polarity of the electrode outside the first groove and the electrode outside the second groove.

[0010] Secondly, this disclosure also provides a method for fabricating a high-performance quartz vibrating beam accelerometer, comprising: A first metal film is deposited on both sides of a quartz wafer. The outline of the stress amplification unit is etched on the first metal film. The first metal film on both sides of the first flexible support beam and the second flexible support beam is removed. The first flexible support beam and the second flexible support beam are etched and thinned using a quartz wet etching process. After removing the first metal film on the surface of the first vibration beam mounting groove and the second vibration beam mounting groove, the first vibration beam mounting groove and the second vibration beam mounting groove are etched using a quartz wet etching process. The first flexible support beam and the second flexible support beam are thinned a second time to prepare the stress amplification unit. A second metal film is deposited on both sides of another quartz wafer. The outline of the resonant unit is etched on the second metal film. The first driving groove and the second metal film on both sides of the second driving groove are removed. The first driving groove and the second driving groove are etched by a quartz wet etching process to prepare the resonant unit. A third metal film is obtained by vapor deposition on the surface of the stress amplification unit and the surface of the resonant unit respectively. Photoresist is uniformly spin-coated on the surface of the third metal film. A photoresist mask with the same size as the electrode is formed on the surface of the stress amplification unit based on the electrode mask plate. The photoresist mask is used as a masking layer to etch electrodes on the surface of the stress amplification unit and the surface of the resonant unit respectively. The stress amplification unit and the resonant unit are bonded together by connecting the electrodes on the stress amplification unit and the electrodes on the resonant unit using wire bonding, wherein an epoxy resin adhesive with added quartz powder is used as the bonding material.

[0011] According to some embodiments of the second aspect of this application, both the first metal film and the second metal film are composed of a chromium layer and a gold layer, the thickness of the chromium layer is 500 angstroms, the thickness of the gold layer is 2000 angstroms, the chromium layer is located between the quartz wafer and the gold layer, and the chromium layer is used to adhere the quartz wafer and the gold layer.

[0012] According to some embodiments of the second aspect of this application, along the thickness direction of the quartz vibrating beam accelerometer, the thickness of the first flexible support beam and the second flexible support beam is not greater than 20% of the thickness of the U-shaped mass load block.

[0013] According to some embodiments of the second aspect of this application, along the thickness direction of the quartz vibrating beam accelerometer, the depth of the first drive groove and the second drive groove is not less than 30% of the thickness of the vibrating beam; along the length direction of the vibrating beam, the length of the first drive groove and the second drive groove is not less than 80% of the length of the vibrating beam, and the width of the first drive groove and the second drive groove is not less than 70% of the width of the vibrating beam.

[0014] The embodiments disclosed herein include at least the following beneficial effects: (1) The high-performance quartz vibrating beam accelerometer includes a stress amplification unit and a resonant unit. The stress amplification unit includes a first vibrating beam mounting groove and a second vibrating beam mounting groove. The resonant unit includes a vibrating beam, a first vibrating beam mounting arm, a second vibrating beam mounting arm, a first driving groove, and a second driving groove. The first driving groove and the second driving groove are respectively disposed on the upper and lower surfaces of the vibrating beam, which can indirectly reduce the thickness of the vibrating beam. This not only improves the sensitivity of the quartz vibrating beam accelerometer but also shortens the distance between the positive and negative electrodes, thereby improving the electric field driving efficiency and reducing the impedance of the quartz vibrating beam accelerometer. The first vibrating beam mounting arm and the second vibrating beam mounting arm are disposed at both ends of the vibrating beam. The first vibrating beam mounting arm and the second vibrating beam mounting arm are respectively embedded in the first vibrating beam mounting groove and the second vibrating beam mounting groove, so that the resonant unit is fixedly assembled on the stress amplification unit, which enhances the stability of the quartz vibrating beam accelerometer structure.

[0015] (2) The method for preparing the high-performance quartz vibrating beam accelerometer provided in this embodiment of the present disclosure, by separately processing and reassembling the stress amplification unit and the resonant unit, and by cleaning the quartz wafer, performing two thinning processes on the first flexible support beam and the second flexible support beam, and using epoxy resin adhesive with added quartz powder to bond the stress amplification unit and the resonant unit, can effectively suppress the surface roughness deterioration during the preparation of the quartz vibrating beam accelerometer, thereby improving the performance stability of the quartz vibrating beam accelerometer.

[0016] Other features and advantages of this disclosure will be set forth in the following description and will be apparent in part from the description or may be learned by practicing this disclosure. Attached Figure Description

[0017] The accompanying drawings are provided to further understand the technical solutions of this disclosure and constitute a part of the specification. They are used together with the embodiments of this disclosure to explain the technical solutions of this disclosure and do not constitute a limitation on the technical solutions of this disclosure.

[0018] Figure 1 This is a schematic diagram of an optional structure for a quartz vibrating beam accelerometer (unassembled) provided in an embodiment of this disclosure; Figure 2 This is a schematic diagram of an optional structure of the first principal surface of a quartz vibrating beam accelerometer provided in an embodiment of this disclosure; Figure 3 A schematic cross-sectional view of an optional quartz vibrating beam accelerometer provided in an embodiment of this disclosure; Figure 4 A schematic diagram of an optional structure for assembling the vibration beam of a quartz vibrating beam accelerometer according to an embodiment of this disclosure; Figure 5 This is a schematic diagram of an optional electrode distribution for a quartz vibrating beam accelerometer provided in an embodiment of this disclosure; Figure 6 for Figure 5 A schematic diagram of an alternative electrode distribution around the resonant unit in region A; Figure 7 A schematic diagram of another optional structure for assembling the vibration beam of the quartz vibrating beam accelerometer provided in this embodiment of the present disclosure; Figure 8 A schematic diagram of another optional structure of the resonant unit provided in the embodiments of this disclosure; Figure 9 A schematic diagram of another optional structure of the resonant unit provided in the embodiments of this disclosure; Figure 10 This is a schematic diagram of an optional process for fabricating a high-performance quartz vibrating beam accelerometer provided in an embodiment of this disclosure; Figure 11Provided for the embodiments of this disclosure Figure 10 The detailed flowchart of step S1001; Figure 12 Provided for the embodiments of this disclosure Figure 11 A schematic diagram of an optional processing flow for the stress amplification unit in steps S1101-S1110; Figure 13 Provided for the embodiments of this disclosure Figure 10 The detailed flowchart of step S1002; Figure 14 Provided for the embodiments of this disclosure Figure 13 A schematic diagram of an optional fabrication process for the resonant unit in steps S1301-S1308.

[0019] Figure label: Stress amplification unit 1, resonant unit 2, U-shaped mass load block 11, first flexible support beam 12a, second flexible support beam 12b, isolation frame 13, first connecting part 14a, second connecting part 14b, base 15, first mounting frame 16a, second mounting frame 16b, first vibration beam mounting groove 17a, second vibration beam mounting groove 17b, vibration beam 21, first vibration beam mounting arm 22a, second vibration beam mounting arm 22b, first drive groove 23a, first groove outer electrode 31, second groove outer electrode 32, first groove inner electrode 33, second groove inner electrode 34, first connecting lead 35a, second connecting lead 35b, bottom vibration beam 24 Detailed Implementation To make the objectives, technical solutions, and advantages of this disclosure clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and are not intended to limit the scope of this disclosure.

[0020] It should be noted that in the various specific embodiments of this disclosure, when processing is required based on data related to the characteristics of the target object, such as target object attribute information or a set of attribute information, the permission or consent of the target object will be obtained first. Furthermore, the collection, use, and processing of this data will comply with relevant laws, regulations, and standards. The target object can be a user. In addition, when embodiments of this disclosure require obtaining target object attribute information, separate permission or consent from the target object will be obtained through pop-ups or redirection to a confirmation page. Only after obtaining the target object's separate permission or consent will the necessary target object-related data for the normal operation of the embodiments of this disclosure be obtained.

[0021] In this disclosure, the terms "module" or "unit" refer to a computer program or part of a computer program that has a predetermined function and works with other related parts to achieve a predetermined goal, and can be implemented wholly or partially using software, hardware (such as processing circuitry or memory), or a combination thereof. Similarly, a processor (or multiple processors or memory) can be used to implement one or more modules or units. Furthermore, each module or unit can be part of an overall module or unit that includes the functionality of that module or unit.

[0022] To facilitate understanding of the technical solutions provided in the embodiments of this disclosure, some key terms used in the embodiments of this disclosure will be explained below: Quartz vibrating beam accelerometers are high-precision inertial sensors based on the piezoelectric effect and resonance principle of quartz crystals. By detecting the change in the resonant frequency of the vibrating beam in the resonant unit with the external acceleration, they can accurately measure acceleration and are the core device in the field of high-precision inertial measurement.

[0023] Quartz wet etching is a wet chemical processing technology that utilizes a chemical etching solution to selectively react with quartz crystals, achieving micro-forming, thinning, and patterning of the surface of quartz materials. It is a core process in the fabrication of quartz micro- and nano-devices (such as quartz vibrating beam accelerometers and quartz resonators). Compared with dry etching, it has the advantages of simple process, good etching uniformity, low cost, and no plasma bombardment damage. It is suitable for the forming and thinning of fine microstructures such as quartz vibrating beams and flexible support beams.

[0024] Quartz beam accelerometers, as precision inertial sensors, are widely used in high-precision inertial measurement fields due to their advantages such as high sensitivity, high stability, low power consumption, and strong anti-interference capabilities. In existing technologies, quartz beam accelerometers are mainly divided into two categories: integrated quartz beam accelerometers and split-type quartz beam accelerometers. Integrated quartz beam accelerometers are fabricated from a single quartz wafer, resulting in strong structural integrity. However, because these integrated quartz beam accelerometers require deep etching in the direction perpendicular to their own plane, this processing method easily leads to incomplete surface structures on the beam, resulting in significant surface roughness, which in turn causes a decrease in the accelerometer's sensitivity and quality factor. Furthermore, limited by the integrated fabrication process, metal electrodes can usually only be fabricated on a single surface of the beam. Effective electrode fabrication on the sides and back of the beam is difficult, and the single-sided electrode design results in insufficient electrode driving efficiency, further restricting the accelerometer's response speed and measurement accuracy.

[0025] Unlike integrated structures, split-type quartz vibrating beam accelerometers are assembled from separately machined stress amplification structures and quartz tuning forks. The quartz tuning forks used in split-type accelerometers all operate in a double-beam conjugate vibration mode. During this double-beam conjugate vibration, vibration interference is easily generated, leading to low stress transmission efficiency and consequently reduced accelerometer sensitivity. Furthermore, vibration reflection increases ineffective energy consumption, resulting in higher power consumption. In addition, the lack of a slot structure in the quartz tuning fork results in a large distance between its positive and negative electrodes, leading to insufficient electric field strength between the electrodes and low drive signal transmission efficiency, thus affecting electrode drive efficiency. Both existing accelerometer structures are insufficient to meet the requirements of high-precision inertial measurement applications.

[0026] Based on this, the present disclosure provides a high-performance quartz vibrating beam accelerometer and its preparation method, which can not only improve the sensitivity of the quartz vibrating beam accelerometer and shorten the distance between the positive and negative electrodes, thereby improving the electric field driving efficiency, but also effectively suppress the surface roughness degradation during the preparation process of the quartz vibrating beam accelerometer, thereby improving the performance stability of the quartz vibrating beam accelerometer.

[0027] The following is in conjunction with the appendix Figure 1-2 The high-performance quartz vibrating beam accelerometer provided in the embodiments of this disclosure will be further described.

[0028] Reference Figure 1-2 , Figure 1 This is a schematic diagram of an optional structure of the quartz vibrating beam accelerometer (unassembled) provided in an embodiment of this disclosure. Figure 2This is a schematic diagram of an optional structure of the first main surface of the quartz vibrating beam accelerometer provided in an embodiment of this disclosure. The high-performance quartz vibrating beam accelerometer includes a stress amplification unit 1 and a resonant unit 2. The stress amplification unit 1 includes a U-shaped mass load block 11, a first flexible support beam 12a, a second flexible support beam 12b, an isolation frame 13, a first connecting part 14a, a second connecting part 14b, a base 15, a first mounting frame 16a, a second mounting frame 16b, a first vibration beam mounting groove 17a, and a second vibration beam mounting groove 17b. The resonant unit 2 includes a vibration beam 21, a first vibration beam mounting arm 22a, a second vibration beam mounting arm 22b, a first drive groove 23a, and a second drive groove 23b (not shown in the figures). The first driving groove 23a and the second driving groove 23b are respectively disposed on the upper and lower surfaces of the vibrating beam 21, and the first vibrating beam mounting arm 22a and the second vibrating beam mounting arm 22b are disposed at both ends of the vibrating beam 21. When the first vibrating beam mounting arm 22a and the second vibrating beam mounting arm 22b are respectively embedded in the first vibrating beam mounting groove 17a and the second vibrating beam mounting groove 17b, the resonant unit 2 is fixedly assembled on the stress amplification unit 1. By providing the first driving groove and the second driving groove on the vibrating beam, the thickness of the vibrating beam is indirectly reduced, which not only improves the sensitivity of the quartz vibrating beam accelerometer, but also shortens the distance between the positive and negative electrodes, improves the electric field driving efficiency, and thus reduces the impedance of the quartz vibrating beam accelerometer.

[0029] It should also be noted that the first drive groove and the second drive groove are located at the center of the upper and lower surfaces of the vibrating beam, and their lengths are equal to or slightly shorter than the length of the vibrating beam.

[0030] Reference Figure 3 , Figure 3 This is a schematic cross-sectional view of an optional quartz vibrating beam accelerometer provided in an embodiment of this disclosure, wherein... Figure 3 (a) is a cross-sectional view of the plane containing the U-shaped mass load block 11. Figure 3 (b) is a cross-sectional view in the plane containing the first flexible support beam 12a and the second flexible support beam 12b. Figure 3 (c) in the diagram is a cross-sectional view of the vibrating beam 21.

[0031] Reference Figure 2 and Figure 4 , Figure 4This is a schematic diagram of an optional structure for assembling the vibration beam of a quartz vibrating beam accelerometer according to an embodiment of this disclosure. A first flexible support beam 12a and a second flexible support beam 12b extend symmetrically from the top of the base 15. The free ends of the first flexible support beam 12a and the second flexible support beam 12b are fixedly connected to a U-shaped mass load block 11. The opening of the U-shaped mass load block 11 faces the opening of the base 15, i.e., the openings of the U-shaped mass load block 11 and the base 15 are opposite each other. The vibration beam 21 is suspended between the U-shaped mass load block 11 and the base 15. The first vibration beam mounting arm 22a of the vibration beam 21 is embedded in the first vibration beam mounting groove 17a at the bottom of the opening of the U-shaped mass load block 11, and the second vibration beam mounting arm 22b of the vibration beam 21 is embedded in the second vibration beam mounting groove 17b at the bottom of the opening of the base 15, so that both ends of the vibration beam 21 are connected to the U-shaped mass load block 11 and the base 15, respectively.

[0032] Refer again Figure 1 The bottom end of the base 15 is connected to the inner side of the isolation frame 14 via the first connecting part 14a, and the outer side of the isolation frame 14 is connected to the first mounting frame 16a and the second mounting frame 16b via the second connecting part 14b. The first mounting frame 16a and the second mounting frame 16b are symmetrically arranged.

[0033] Refer again Figure 2 , Figure 2 The left side shows the first main surface of stress amplification unit 1. Figure 2 The right side shows the first main surface of the resonant unit 2. The first driving groove 23a is disposed on the first main surface of the vibrating beam 21, and the second driving groove 23b is disposed on the second main surface of the vibrating beam 21 (not shown in the figure). The first driving groove 23a and the second driving groove 23b are symmetrically arranged.

[0034] Reference Figure 5 , Figure 5 This is a schematic diagram of an optional electrode distribution for a quartz vibrating beam accelerometer provided in an embodiment of this disclosure. The black and gray areas represent electrode distribution areas with different polarities. (Refer to...) Figure 6 , Figure 6 for Figure 5 A schematic diagram of an optional electrode distribution around the resonant unit in region A shows electrodes disposed on both the inner and outer sides of the first driving slot 23a and the second driving slot 23b. The electrode 33 inside the first slot and the electrode 34 inside the second slot have the same polarity, while the polarity of the electrodes 33 inside the first slot and the electrodes 34 outside the second slot is opposite to that of the electrodes 31 outside the first slot and the electrodes 32 outside the second slot. The electrodes on the resonant unit 2 are connected to the electrodes on the base 15 via the first connecting lead 35a and the second connecting lead 35b.

[0035] In one embodiment, refer to Figure 7 , Figure 7This is a schematic diagram of another optional structure for assembling the vibration beam of the quartz vibrating beam accelerometer provided in this embodiment. Two additional bottom vibration beam mounting slots, symmetrical to the first and second vibration beam mounting slots, are provided at the bottom of the stress amplification unit. A bottom vibration beam 24 is assembled through these two bottom vibration beam mounting slots, and the bottom vibration beam 24 has the same dimensions as the vibration beam 21. This dual vibration beam design enables differential drive, effectively improving the sensitivity of the quartz vibrating beam accelerometer while enhancing its anti-interference capability, thereby improving the working stability of the quartz vibrating beam accelerometer.

[0036] In one embodiment, refer to Figure 8 , Figure 8 This is a schematic diagram of another optional structure of the resonant unit provided in the embodiments of this disclosure. The vibration beam of the resonant unit is a straight beam structure without a driving groove. The straight beam structure has a simple processing technology and higher structural rigidity, and is suitable for application scenarios with low requirements for driving effect and sensitivity.

[0037] In one embodiment, refer to Figure 9 , Figure 9 This is a schematic diagram of another optional structure of the resonant unit provided in the embodiments of this disclosure. The vibration beam of the resonant unit is a three-section beam structure with three driving grooves. This three-section beam structure can obtain a stronger resonant driving effect and is suitable for application scenarios with high driving effect requirements.

[0038] In one embodiment, in low-temperature applications, the stress amplification unit is fabricated using silicon-based materials with simpler processing technology. Meanwhile, other materials are attached to the surface of the U-shaped mass load block of the stress amplification unit. By increasing the weight of the U-shaped mass load block, the sensitivity of the quartz vibrating beam accelerometer can be improved.

[0039] In one embodiment, in low-temperature scenarios, other stress-sensitive resonators are used as the resonant unit, such as SAW, BAW, and silicon resonators. It is important to note that to ensure the linearity and other key parameters of the quartz beam accelerometer meet design requirements, all resonators used must be fabricated as beam structures.

[0040] In addition, this disclosure also provides a method for fabricating a high-performance quartz vibrating beam accelerometer, referring to... Figure 10 , Figure 10 This is an optional flowchart illustrating a method for fabricating a high-performance quartz vibrating beam accelerometer provided in this embodiment of the present disclosure, including but not limited to steps S1001 to S1004.

[0041] Step S1001: A first metal film is deposited on both sides of the quartz wafer. The outline of the stress amplification unit is etched on the first metal film. The first metal film on both sides of the first flexible support beam and the second flexible support beam is peeled off. The first flexible support beam and the second flexible support beam are etched and thinned using a quartz wet etching process. After peeling off the first metal film on the surface of the first vibration beam mounting groove and the second vibration beam mounting groove, the first vibration beam mounting groove and the second vibration beam mounting groove are etched using a quartz wet etching process. The first flexible support beam and the second flexible support beam are thinned a second time to prepare the stress amplification unit.

[0042] Step S1002: A second metal film is deposited on both sides of another quartz wafer. The outline of the resonant unit is etched on the second metal film. The second metal film on both sides of the first driving groove and the second driving groove is peeled off. The first driving groove and the second driving groove are etched by a quartz wet etching process to prepare the resonant unit.

[0043] Step S1003: A third metal film is obtained by vapor deposition on the surface of the stress amplification unit and the surface of the resonant unit, respectively. Photoresist is uniformly spin-coated on the surface of the third metal film. A photoresist mask with the same size as the electrode is formed on the surface of the stress amplification unit based on the electrode mask plate. The photoresist mask is used as a masking layer to etch electrodes on the surface of the stress amplification unit and the surface of the resonant unit, respectively.

[0044] Specifically, a third metal film is deposited on the surfaces of the stress amplification unit and the resonant unit, respectively. This third metal film can consist of a chromium layer and a gold layer. Photoresist is uniformly spin-coated onto the surface of the third metal film. The stress amplification unit and the resonant unit are then pre-baked to improve the adhesion between the photoresist and the third metal film. An electrode mask with a pre-defined electrode pattern is obtained and placed in the corresponding areas of the stress amplification unit and the resonant unit. After UV exposure and development, an electrode photoresist mask with dimensions consistent with the electrode pattern is formed. This mask is then post-baked to further solidify the electrode photoresist mask and improve its resistance to etching in subsequent etching processes. Using the electrode photoresist mask as a masking layer, electrodes are etched onto the surfaces of the stress amplification unit and the resonant unit, respectively. These electrodes are used to drive the vibrating beam. After etching, any remaining photoresist is stripped and cleaned.

[0045] It is understandable that, in the actual preparation process, the electrode size should be adjusted according to the actual size of the quartz vibrating beam accelerometer, and this application does not limit the specific adjustment method.

[0046] Step S1004: Bond the stress amplification unit and the resonant unit by connecting the electrodes on the stress amplification unit and the electrodes on the resonant unit using wire bonding.

[0047] Specifically, an epoxy resin adhesive with added quartz powder is used to bond the stress amplification unit and the resonant unit. The electrodes formed on the stress amplification unit and the resonant unit in step S1003 are used as bonding points, and wire bonding is used to connect the electrodes on the stress amplification unit and the electrodes on the resonant unit. By using an epoxy resin adhesive with a coefficient of thermal expansion close to that of quartz, thermal stress caused by temperature changes can be effectively reduced, avoiding the propagation of microcracks and grain boundary separation on the quartz surface due to thermal stress differences. At the same time, adding quartz powder to the epoxy resin adhesive can reduce the curing shrinkage rate of the epoxy resin adhesive layer, avoiding tensile stress on the quartz surface caused by the shrinkage of the epoxy resin adhesive layer, thereby effectively preventing the stretching and amplification of surface roughness defects.

[0048] Reference Figure 11 , Figure 11 Provided for the embodiments of this disclosure Figure 10 The detailed flowchart of step S1001 shows that the fabrication method of this high-performance quartz vibrating beam accelerometer may include, but is not limited to, steps S1101 to S1110. (Refer to...) Figure 12 , Figure 12 Provided for the embodiments of this disclosure Figure 11 A schematic diagram of an optional processing flow for the stress amplification unit in steps S1101-S1110.

[0049] Step S1101: A first metal film is obtained by vapor deposition on both sides of the cleaned quartz crystal, and the resulting structure is as follows. Figure 12 As shown in (a).

[0050] Step S1102: Positive photoresist is spin-coated onto both sides of the vapor-deposited quartz crystal to obtain a stress mask with a pre-defined stress amplification unit pattern. After ultraviolet light exposure and development, the stress amplification unit pattern on the stress mask is transferred onto the positive photoresist to form a stress photoresist mask. The resulting structure is as follows. Figure 12 As shown in (b).

[0051] Step S1103: Using the stress photoresist mask as a masking layer, etch the first metal film to transfer the stress amplification unit pattern from the stress photoresist mask onto the first metal film, resulting in the structure shown below. Figure 12 As shown in (c).

[0052] Step S1104: Strip and clean the residual photoresist, resulting in the structure shown below. Figure 12 As shown in (d).

[0053] Step S1105: The basic outline of the stress amplification unit is etched on the first metal film using a quartz wet etching process, and the resulting structure is as follows. Figure 12 As shown in (e).

[0054] Step S1106: Repeat the evaporation-etching-stripping photoresist process in steps S1102-S1104 to remove the first metal film on both sides of the first flexible support beam and the second flexible support beam. The resulting structure is as follows. Figure 12 As shown in (f).

[0055] Step S1107: The first flexible support beam and the second flexible support beam are etched using a quartz wet etching process, and the first flexible support beam and the second flexible support beam are then thinned. The resulting structure is as follows. Figure 12 As shown in (g).

[0056] Step S1108: Repeat the vapor deposition-etching-stripping process in steps SS1102-S1104 to remove the first metal film from the surfaces of the first and second vibration beam mounting grooves, resulting in the structure shown below. Figure 12 As shown in (h).

[0057] Step S1109: The first and second vibration beam mounting grooves are etched using a quartz wet etching process, and the first and second flexible support beams are subjected to a secondary thinning operation, resulting in the structure shown below. Figure 12 As shown in (k).

[0058] Step S1110: Remove all the first metal film from the surface of the quartz crystal to prepare the stress amplification unit, the resulting structure is as follows. Figure 12 As shown in (n).

[0059] Reference Figure 13 , Figure 13 Provided for the embodiments of this disclosure Figure 10 The detailed flowchart of step S1002 shows that the fabrication method of this high-performance quartz vibrating beam accelerometer may include, but is not limited to, steps S1301 to S1308. (Refer to...) Figure 14 , Figure 14 Provided for the embodiments of this disclosure Figure 13 A schematic diagram of an optional fabrication process for the resonant unit in steps S1301-S1308.

[0060] Step S1301: A second metal film is obtained by vapor deposition on both sides of the cleaned quartz crystal, and the resulting structure is as follows. Figure 14 As shown in (a).

[0061] Step S1302: Positive photoresist is spin-coated onto both sides of the vapor-deposited quartz crystal to obtain a resonant mask with a pre-defined resonant unit pattern. After ultraviolet light exposure and development, the resonant unit pattern on the resonant mask is transferred onto the positive photoresist to form a resonant photoresist mask. The resulting structure is as follows: Figure 14 As shown in (b).

[0062] Step S1303: Using the resonant photoresist mask as a masking layer, etch the second metal film to transfer the resonant unit pattern from the resonant photoresist mask onto the second metal film, resulting in the structure shown below. Figure 14 As shown in (c).

[0063] Step S1304: Strip and clean the residual photoresist, resulting in the structure shown below. Figure 14 As shown in (d).

[0064] Step S1305: The basic outline of the resonant unit is etched on the second metal film using a quartz wet etching process, and the resulting structure is as follows. Figure 14 As shown in (e).

[0065] Step S1306: Repeat the evaporation-etching-stripping photoresist process in steps S1102-S1104 to remove the second metal film on both sides of the first and second driving trenches, resulting in the structure shown below. Figure 14 As shown in (f).

[0066] Step S1307: The first driving groove and the second driving groove are etched using a quartz wet etching process, and the resulting structure is as follows. Figure 14 As shown in (g).

[0067] Step S1308: Remove all the second metal film from the surface of the quartz crystal to prepare the resonant unit. The resulting structure is as follows: Figure 14 As shown in (h).

[0068] It should be noted that the first metal film and the second metal film obtained by the above vapor deposition are both composed of a chromium layer and a gold layer. The thickness of the chromium layer is 500 angstroms and the thickness of the gold layer is 2000 angstroms. The chromium layer is located between the quartz wafer and the gold layer and is used to adhere the quartz wafer to the gold layer.

[0069] It should also be noted that, along the thickness direction of the prepared quartz vibrating beam accelerometer, the thickness of the U-shaped mass load block, the isolation frame, the first connecting part, the second connecting part, the base, the first mounting frame, and the second mounting frame are the same.

[0070] It should also be noted that, in the prepared quartz vibrating beam accelerometer, the thickness of the first flexible support beam and the second flexible support beam along the thickness direction of the quartz vibrating beam accelerometer is no more than 20% of the thickness of the U-shaped mass load block.

[0071] It should also be noted that, in the prepared quartz vibrating beam accelerometer, the depth of the first driving groove and the second driving groove along the thickness direction of the quartz vibrating beam accelerometer is not less than 30% of the thickness of the vibrating beam. Along the length direction of the vibrating beam, the length of the first driving groove and the second driving groove is not less than 80% of the length of the vibrating beam, and the width of the first driving groove and the second driving groove is not less than 70% of the width of the vibrating beam.

[0072] It should also be noted that the dimensions of the first and second vibration beam mounting slots are slightly larger than the dimensions of the first and second vibration beam mounting arms, so that the first and second vibration beam mounting arms can be completely embedded within the mounting slots. Understandably, the dimensional difference between the two can be determined based on the type of adhesive used. During the assembly of the quartz vibrating beam accelerometer, the first and second vibration beam mounting slots mate with the first and second vibration beam mounting arms respectively, and are bonded together using adhesive, thus fixing the stress amplification unit and the resonant unit together as a single unit.

[0073] In summary, the high-performance quartz vibrating beam accelerometer provided in this disclosure indirectly reduces the thickness of the vibrating beam by setting driving grooves on the upper and lower surfaces of the vibrating beam of the resonant unit. This not only improves the sensitivity of the quartz vibrating beam accelerometer but also shortens the distance between the positive and negative electrodes, thereby improving the electric field driving efficiency and reducing the impedance of the quartz vibrating beam accelerometer. Furthermore, the fabrication method of the high-performance quartz vibrating beam accelerometer provided in this disclosure, through two thinning processes on the flexible support beam and the use of epoxy resin adhesive with added quartz powder to bond the stress amplification unit and the resonant unit, effectively suppresses surface roughness degradation during the fabrication process of the quartz vibrating beam accelerometer, ensuring the stability of the quartz vibrating beam accelerometer.

[0074] The terms “first,” “second,” “third,” “fourth,” etc. (if present) in this disclosure and the foregoing drawings are used to distinguish similar objects and are not necessarily used to describe a particular order or sequence. It should be understood that such data can be interchanged where appropriate to describe embodiments of this disclosure, for example, those that can be implemented in orders other than those illustrated or described herein. Furthermore, the terms “comprising” and “having,” and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatuses.

[0075] It should be understood that in this disclosure, "at least one item" means one or more, and "more than one" means two or more. "And / or" is used to describe the relationship between related objects, indicating that three relationships can exist. For example, "A and / or B" can represent three cases: only A exists, only B exists, and both A and B exist simultaneously, where A and B can be singular or plural. The character " / " generally indicates that the preceding and following related objects are in an "or" relationship. "At least one of the following" or similar expressions refer to any combination of these items, including any combination of single or plural items. For example, at least one of a, b, or c can represent: a, b, c, "a and b", "a and c", "b and c", or "a and b and c", where a, b, and c can be single or multiple.

[0076] It should be understood that in the description of the embodiments of this disclosure, "multiple" means two or more, "greater than", "less than", "exceeding" etc. are understood to exclude the number itself, and "above", "below", "within" etc. are understood to include the number itself.

[0077] In the embodiments provided in this disclosure, it should be understood that the disclosed systems, apparatuses, and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between apparatuses or units may be electrical, mechanical, or other forms.

[0078] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0079] Furthermore, the functional units in the various embodiments of this disclosure can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0080] If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this disclosure, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods of the various embodiments of this disclosure. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0081] It should also be understood that the various implementation methods provided in this disclosure can be combined arbitrarily to achieve different technical effects.

[0082] The above is a detailed description of the preferred embodiments of this disclosure. However, this disclosure is not limited to the above embodiments. Those skilled in the art can make various equivalent modifications or substitutions without departing from the spirit of this disclosure. All such equivalent modifications or substitutions are included within the scope defined by the claims of this disclosure.

Claims

1. A high-performance quartz vibrating beam accelerometer, characterized in that, The device includes a stress amplification unit and a resonant unit. The stress amplification unit includes a first vibration beam mounting groove and a second vibration beam mounting groove. The resonant unit includes a vibration beam, a first vibration beam mounting arm, a second vibration beam mounting arm, a first drive groove, and a second drive groove. The first drive groove and the second drive groove are respectively disposed on the upper and lower surfaces of the vibration beam. The first vibration beam mounting arm and the second vibration beam mounting arm are disposed at both ends of the vibration beam. The first vibration beam mounting arm and the second vibration beam mounting arm are respectively embedded in the first vibration beam mounting groove and the second vibration beam mounting groove, so that the resonant unit is fixedly assembled on the stress amplification unit.

2. The high-performance quartz vibrating beam accelerometer according to claim 1, characterized in that, The stress amplification unit also includes a U-shaped mass load block, a first flexible support beam, a second flexible support beam, an isolation frame, a first connecting part, a second connecting part, a base, a first mounting frame, and a second mounting frame.

3. The high-performance quartz vibrating beam accelerometer according to claim 2, characterized in that, The first flexible support beam and the second flexible support beam extend symmetrically from the top of the base. The free ends of the first flexible support beam and the second flexible support beam are fixedly connected to the U-shaped mass load block. The opening of the U-shaped mass load block faces the opening of the base. The vibration beam is suspended between the U-shaped mass load block and the base. The two ends of the vibration beam are respectively connected to the bottom end of the opening of the U-shaped mass load block and the bottom end of the opening of the base.

4. The high-performance quartz vibrating beam accelerometer according to claim 2, characterized in that, The bottom end of the base is connected to the inner side of the isolation frame via the first connecting part, and the outer side of the isolation frame is connected to the first mounting frame and the second mounting frame via the second connecting part. The first mounting frame and the second mounting frame are symmetrically arranged.

5. The high-performance quartz vibrating beam accelerometer according to claim 1, characterized in that, Electrodes are provided on both the inner and outer sides of the first driving slot and the second driving slot. The polarity of the electrode inside the first slot is the same as that of the electrode inside the second slot, and the polarity of the electrode inside the first slot and the electrode inside the second slot is opposite to that of the electrode outside the first slot and the electrode outside the second slot.

6. A method for preparing a high-performance quartz vibrating beam accelerometer, applicable to the high-performance quartz vibrating beam accelerometer described in any one of claims 1 to 5, characterized in that, include: A first metal film is deposited on both sides of a quartz wafer. The outline of the stress amplification unit is etched on the first metal film. The first metal film on both sides of the first flexible support beam and the second flexible support beam is removed. The first flexible support beam and the second flexible support beam are etched and thinned using a quartz wet etching process. After removing the first metal film on the surface of the first vibration beam mounting groove and the second vibration beam mounting groove, the first vibration beam mounting groove and the second vibration beam mounting groove are etched using a quartz wet etching process. The first flexible support beam and the second flexible support beam are thinned a second time to prepare the stress amplification unit. A second metal film is deposited on both sides of another quartz wafer. The outline of the resonant unit is etched on the second metal film. The first driving groove and the second metal film on both sides of the second driving groove are removed. The first driving groove and the second driving groove are etched by a quartz wet etching process to prepare the resonant unit. A third metal film is obtained by vapor deposition on the surface of the stress amplification unit and the surface of the resonant unit respectively. Photoresist is uniformly spin-coated on the surface of the third metal film. A photoresist mask with the same size as the electrode is formed on the surface of the stress amplification unit based on the electrode mask plate. The photoresist mask is used as a masking layer to etch electrodes on the surface of the stress amplification unit and the surface of the resonant unit respectively. The stress amplification unit and the resonant unit are bonded together by connecting the electrodes on the stress amplification unit and the electrodes on the resonant unit using wire bonding, wherein an epoxy resin adhesive with added quartz powder is used as the bonding material.

7. The high-performance quartz vibrating beam accelerometer according to claim 6, characterized in that, Both the first metal film and the second metal film are composed of a chromium layer and a gold layer. The thickness of the chromium layer is 500 angstroms and the thickness of the gold layer is 2000 angstroms. The chromium layer is located between the quartz wafer and the gold layer and is used to adhere the quartz wafer to the gold layer.

8. The high-performance quartz vibrating beam accelerometer according to claim 6, characterized in that, Along the thickness direction of the quartz vibrating beam accelerometer, the thickness of the first flexible support beam and the second flexible support beam is no more than 20% of the thickness of the U-shaped mass load block.

9. The high-performance quartz vibrating beam accelerometer according to claim 6, characterized in that, Along the thickness direction of the quartz vibrating beam accelerometer, the depth of the first drive groove and the second drive groove is not less than 30% of the thickness of the vibrating beam; along the length direction of the vibrating beam, the length of the first drive groove and the second drive groove is not less than 80% of the length of the vibrating beam, and the width of the first drive groove and the second drive groove is not less than 70% of the width of the vibrating beam.

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