Method for reducing mechanical coupling error of quartz sensor device

Abstract

This application relates to the technical field of the preparation of quartz sensor devices, and specifically relates to a method for reducing the mechanical coupling error of quartz sensor devices, which includes the following steps: processing a Z-cut quartz wafer to form a plurality of quartz sensor chips to obtain a quartz sensor wafer, wherein each side wall of the quartz sensor chip has a crystal edge; coating the quartz sensor wafer to form a first metal film layer; forming a first photoresist on the surface of the first metal film layer; exposing the first photoresist on the crystal edge by a side exposure method; transferring the exposed pattern of the first photoresist to the first metal film layer to obtain an exposed crystal edge; eliminating the exposed crystal edge by a quartz wet chemical etching method. This application has the effect of accurately eliminating the crystal edges on the side walls of the quartz sensor chips at fixed points and positions, and reducing the mechanical coupling error of the quartz sensor chips.

Description

Technical Field

[0001] This application relates to the technical field of quartz sensor device preparation, and in particular to a method for reducing the mechanical coupling error of quartz sensor devices. Background Art

[0002] A quartz sensor device is a device that uses the piezoelectric effect and resonance effect of a quartz crystal for measurement, monitoring, and control. Quartz sensors have the characteristics of high precision, high stability, high resolution, etc., and are widely used in fields such as micro inertial navigation systems, attitude measurement and control.

[0003] The mechanical coupling error of a quartz sensor chip refers to the output error of mechanical origin caused by factors within the device's internal structure or external environment. It is the main source of errors in quartz inertial sensing systems and also the main factor affecting the overall accuracy of quartz inertial sensing systems. Factors causing mechanical coupling errors include manufacturing process deviations and non-uniformities, changes in quartz frequency and mechanical structure due to temperature changes, external mechanical vibrations and impacts, etc. Among them, the deviations and non-uniformities in the manufacturing process of quartz sensor chips are the main factors affecting the mechanical coupling error of quartz sensor chips.

[0004] The manufacturing of quartz sensor chips is usually processed by wet chemical etching. Due to the anisotropy of quartz crystals and the existence of lithography double-sided overlay errors, although the designed quartz sensor chip has a strictly symmetric structure, the structure of the quartz sensor chip obtained after the wet etching process is often not strictly symmetric. This asymmetry is mainly reflected in that one side wall of the quartz sensor chip structure has a larger crystal edge size than the other side wall.

[0005] In related technologies, the electroplated metal balance mass on the quartz sensor chip structure is trimmed by laser etching, which can reduce the asymmetry of the quartz sensor chip structure. However, this method can only adjust the centroid distribution of the quartz sensor chip within a small range, that is, it can only slightly reduce the mechanical coupling error caused by uneven centroid distribution, and cannot reduce the mechanical coupling error caused by the driving mode deviation due to electrode deviation. Or by adjusting corrosion conditions such as the chemical formula of the quartz etching solution, corrosion temperature, and corrosion time, the asymmetry of the quartz sensor chip structure can be reduced to a certain extent. However, after applying these methods in the actual preparation process, the mechanical coupling error caused by the side wall crystal edges of the quartz sensor chip structure still affects the accuracy and stability of the quartz sensor.

[0006] Aiming at the above-mentioned related technologies, there is a problem of poor effect in reducing the mechanical coupling error of quartz sensor devices. Summary of the Invention

[0007] In order to improve the accuracy of precisely eliminating the crystal edges on the sidewalls of the quartz sensor chip for fixed-point positioning, reduce the influence of external vibration or stress on the quartz sensor chip, and improve the reduction effect of the mechanical coupling error of the quartz sensor chip, the purpose of this application is to provide a method for reducing the mechanical coupling error of quartz sensor devices.

[0008] In the first aspect, the method for reducing the mechanical coupling error of quartz sensor devices provided in this application adopts the following technical solutions:

[0009] A method for reducing the mechanical coupling error of quartz sensor devices includes the following steps:

[0010] Process a Z-cut quartz wafer to form multiple quartz sensor chips, obtaining a quartz sensor wafer. Among them, each quartz sensor chip has crystal edges on its sidewalls;

[0011] Deposit a film on the quartz sensor wafer to form a first metal film layer;

[0012] Form a first photoresist on the surface of the first metal film layer;

[0013] Expose the first photoresist on the crystal edges by means of side exposure;

[0014] Transfer the exposed pattern of the first photoresist to the first metal film layer to obtain exposed crystal edges;

[0015] Eliminate the exposed crystal edges by means of quartz wet chemical etching.

[0016] By adopting the above technical solutions, quartz sensor chips are formed by processing on a Z-cut quartz wafer. The quartz sensor chips have uniform (in terms of position, shape, and size) crystal edges. The exposed crystal edges are obtained by fixed-point positioning of the crystal edges through side exposure, and then the exposed crystal edges are eliminated in combination with the quartz wet chemical etching method. First, it is compatible with the quartz sensor chip manufacturing process, simplifying the improvement cost; second, it improves the accuracy of precisely eliminating the crystal edges on the sidewalls of the quartz sensor chip for fixed-point positioning, reduces the influence of external vibration or stress on the quartz sensor chip, and improves the reduction effect of the mechanical coupling error of the quartz sensor chip.

[0017] Optionally, exposing the first photoresist on the crystal edges by means of side exposure includes:

[0018] Determine the front-side exposure angle and the front-side photomask;

[0019] With the front side of the quartz sensor wafer facing up, after tilting the front-side exposure angle, cover the front-side photomask, and the light passing through the front-side photomask is directed towards the front side of the crystal edges to expose the first photoresist covering the front side of the crystal edges.

[0020] By adopting the above technical solution, based on the shape, position, and size settings of the quartz sensor chip, quartz sensor wafer, and crystal edge, the front-side exposure angle and front-side photomask are determined, and fixed-point positioning exposure of the first photoresist on the front side of the crystal edge is achieved, improving the exposure accuracy of the first photoresist on the front side of the crystal edge.

[0021] Optionally, when exposing the first photoresist on the crystal edge by the side exposure method, it further includes:

[0022] Determine the back-side exposure angle and back-side photomask;

[0023] With the back side of the quartz sensor wafer facing up, after tilting the back-side exposure angle, cover the back-side photomask, and the light passing through the back-side photomask is directed towards the back side of the crystal edge to expose the first photoresist covering the back side of the crystal edge.

[0024] By adopting the above technical solution, based on the shape, position, and size settings of the quartz sensor chip, quartz sensor wafer, and crystal edge, the back-side exposure angle and back-side photomask are determined, and fixed-point positioning exposure of the first photoresist on the back side of the crystal edge is achieved, improving the exposure accuracy of the first photoresist on the back side of the crystal edge.

[0025] Optionally, the intersection of the crystal edge and the first metal film layer is exposed and defined as the first line;

[0026] The intersection of the crystal edge and the side of the quartz sensor chip is defined as the second line;

[0027] The distance between the first line and the second line on the same side of the crystal edge is 0.8 - 1.2 μm.

[0028] By adopting the above technical solution, the distance between the first line and the second line is set to 0.8 - 1.2 μm, that is, the etching surface of the first metal layer of the crystal edge is narrowed relative to the front side of the crystal edge itself. This effect comes from narrowing the exposure surface of the first photoresist of the crystal edge when setting the photomask, comprehensively achieving compensation for the corrosion surface of the crystal edge, solving the problem of the diffusion of the quartz crystal edge corrosion surface towards the quartz sidewall caused by the etching characteristics on both sides of the quartz crystal edge, and improving the accuracy of fixed-point positioning for removing the crystal edge.

[0029] Optionally, the distance is 1 μm.

[0030] By adopting the above technical solution, the distance between the first line and the second line on the same side of the crystal edge is limited to 1 μm, further solving the problem of the diffusion of the quartz crystal edge corrosion surface towards the quartz sidewall caused by the etching characteristics on both sides of the quartz crystal edge, and improving the accuracy of fixed-point positioning for removing the crystal edge.

[0031] Optionally, the first line extends along the direction parallel to the Z-cut quartz wafer and intersects with the first metal film layer covering the crystal edge to form a third line;

[0032] After the first photoresist is exposed, the junction with the first metal film layer overlaps with the third line.

[0033] By adopting the above technical solution, the third line is defined based on the first line, and the exposure range is defined based on the third line, improving the accuracy of positioning and removing the crystal edges.

[0034] Optionally, the first metal film layer is a Cr film layer and an Au film layer in sequence. Among them, the coating thickness of the Cr film layer is The coating thickness of the Au film layer is

[0035] By adopting the above technical solution, the thickness of the first metal film layer is defined, improving the thickness uniformity of the exposure end face of the first metal layer corresponding to the exposed crystal edges. While meeting the requirements of the first metal film layer as a protective layer, the exposure influence on the first photoresist is reduced.

[0036] Optionally, the thickness of the first photoresist is 5 - 10 μm.

[0037] By adopting the above technical solution, the thickness of the first photoresist is defined, reducing the corresponding bevel length and improving the thickness uniformity of the exposure end face of the first photoresist corresponding to the exposed crystal edges.

[0038] Optionally, the quartz wet chemical etching method includes etching with an etching solution. The etching solution includes a hydrofluoric acid solution with a mass concentration of 50%, an ammonium bifluoride solution with a mass concentration of 40%, and an organic additive. Among them, the volume ratio of the hydrofluoric acid solution, ammonium bifluoride solution, and organic additive is 1:1.5:0.05 - 0.5, and the organic additive is at least one of glacial acetic acid, ethanol, isopropyl alcohol, and pyridine.

[0039] By adopting the above technical solution, first, etching is carried out with the etching solution, and combined with time control, the fixed-point positioning etching effect is improved; secondly, the types of raw materials of the etching solution are defined. The organic additive is a short-chain organic solution that can be completely dissolved in water, improving the surface activity and promoting the acquisition of a smooth quartz etching sidewall morphology; furthermore, the ratio of the etching solution is defined. Combined with the type definition, the surface charge / potential of the solid-liquid interface is comprehensively changed, affecting the chemical state of the adsorbate on the solid surface and the surface reaction activation energy, thereby changing the adsorption reaction direction and adsorption / desorption reaction kinetics of the adsorbate at the solid-liquid interface and other aspects, realizing that the etching of the crystal edges starts preferentially from the outermost crystal edges, and the crystal edges in the y-direction of the sidewall of the quartz sensor chip have the same etching characteristics. Thus, by controlling the etching duration in combination, the quartz crystal edges are etched to be flush with the sidewall, improving the crystal edge elimination effect of the sidewall of the quartz sensor chip and improving the etching flatness.

[0040] Optionally, the volume ratio of the hydrofluoric acid solution, ammonium bifluoride solution, and organic additive is 1:1.5:0.1.

[0041] By adopting the above technical solution and controlling the etching duration, the elimination effect of the crystal edges on the sidewalls of the quartz sensor chip is improved, and the etching flatness is enhanced.

[0042] In summary, the present application includes at least one of the following beneficial technical effects:

[0043] 1. The exposed crystal edges are obtained by side exposure of the crystal edges, and then the exposed crystal edges are eliminated in combination with the quartz wet chemical etching method, achieving compatibility with the quartz sensor chip manufacturing process and simplifying the improvement cost;

[0044] 2. The accuracy of precisely eliminating the crystal edges on the sidewalls of the quartz sensor chip at a fixed point and position is improved to reduce the influence of external vibration or stress on the quartz sensor chip, and further improve the reduction effect of the mechanical coupling error of the quartz sensor chip;

[0045] 3. By limiting the distance between the first line and the second line on the same side of the crystal edge, the problem of the corrosion surface of the quartz crystal edge diffusing towards the quartz sidewall caused by the etching characteristics on both sides of the quartz crystal edge is further solved, and the accuracy of removing the crystal edge at a fixed point and position is improved;

[0046] 4. By limiting the thicknesses of the first metal layer and the first photoresist, the thickness uniformity of the exposed end faces of the first metal layer and the first photoresist corresponding to the exposed crystal edges is improved, and the accuracy of precisely eliminating the crystal edges on the sidewalls of the quartz sensor chip at a fixed point and position is enhanced;

[0047] 5. By limiting the types and ratio of the raw materials of the etching solution, the etching of the crystal edges preferentially starts from the outermost crystal edges, and the crystal edges on the sidewalls of the quartz sensor chip have the same etching characteristics in all y-directions, so that by controlling the etching duration in combination, the elimination effect of the crystal edges on the sidewalls of the quartz sensor chip is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Figure 1 is a top view structural schematic diagram of the quartz sensor wafer according to Embodiment 1 of the present application;

[0049] Figure 2 is Figure 1 an enlarged view of part A in

[0050] Figure 3 is a structural schematic diagram of the quartz sensor chip according to Embodiment 1 of the present application;

[0051] Figure 4 is a structural schematic diagram of the inclined front side exposure angle of the quartz sensor wafer in Embodiment 1 of the present application;

[0052] Figure 5It is a front view structural schematic diagram of the quartz sensor chip in Embodiment 1 of the present application;

[0053] Figure 6 It is a structural schematic diagram of the first photoresist exposure on the front and side of the crystal edge in Embodiment 1 of the present application;

[0054] Figure 7 It is a structural schematic diagram of the first photoresist exposure on the back side of the crystal edge in Embodiment 1 of the present application;

[0055] Figure 8 It is a structural schematic diagram of the etching of the first metal layer corresponding to the crystal edge in Embodiment 1 of the present application;

[0056] Figure 9 It is a picture of the quartz sensor device in Embodiment 2 of the present application.

[0057] Explanation of reference numerals:

[0058] 1. Quartz sensor wafer; 2. Quartz sensor chip; 3. Crystal edge; 4. First metal film layer; 5. First photoresist; 6. Exposed crystal edge; 7. First line; 8. Second line; 9. Third line. Detailed implementation manners

[0059] The following will further elaborate on the present application in conjunction with the attached Figure 1 - attached Figure 9 , and make a more detailed description of the present application.

[0060] To reduce the mechanical coupling error of the quartz sensor device, in the related art, after methods such as laser etching, adjusting the chemical formula of the quartz etching solution, etching temperature, and etching time, there is a problem of poor removal effect of the crystal edge 3. The present application is proposed in view of this problem.

[0061] Embodiment 1:

[0062] Embodiment 1 of the present application discloses a method for reducing the mechanical coupling error of a quartz sensor device, including the following steps:

[0063] S1. Prepare a Z-cut quartz wafer

[0064] Cut the quartz wafer into a Z-cut quartz wafer. The Z-cut quartz wafer can be of any type such as a square wafer or a circular wafer. In this embodiment, the Z-cut quartz wafer is a square wafer with a length, width, and thickness of 77 mm, 70 mm, and 0.4 mm respectively;

[0065] In this embodiment, the cutting process technology includes:

[0066] S1a. Determine the cutting angle of the quartz wafer by scanning with an X-ray diffractometer, which is set to 0° in the Z direction in this embodiment;

[0067] S1b. Clamp the quartz wafer with a positioning fixture to ensure the cutting angle of the wafer, and then use a multi-wire cutting machine for quartz wafers to perform multi-wire cutting on the quartz wafer with a grinding fluid suitable for cutting quartz materials to obtain Z-cut quartz wafers.

[0068] S2. Process multiple quartz sensor chips 2 on the Z-cut quartz wafer to obtain a quartz sensor wafer 1, where the processing includes:

[0069] S21. Clean the Z-cut quartz wafer

[0070] Place the Z-cut quartz wafer into a strong alkaline cleaning agent and an acidic cleaning agent in sequence in steps for two-step cleaning to remove the oil stains on the surface of the Z-cut quartz wafer. Among them, each step of cleaning is carried out by water bath heating, and the single-step cleaning time is not less than 10 minutes. After each step of cleaning, the Z-cut quartz wafer needs to be placed in deionized water for cleaning for not less than 10 minutes. After the cleaning is completed, the Z-cut quartz wafer is spun dry and baked for 10 minutes;

[0071] After the Z-cut quartz wafer is cleaned, it is detected by a white light interferometer, a high-precision microscope, and a strong light lamp to confirm that there are no oil stains and dust on the surface of the Z-cut quartz wafer.

[0072] S22. Pre-corrosion

[0073] Place the cleaned and dried Z-cut quartz wafer into a pre-corrosion solution for pre-corrosion to remove the loose layer of quartz; among them, the pre-corrosion solution can be one of an organic corrosion solution and an inorganic corrosion solution. In one embodiment, the organic corrosion solution, by weight percentage, consists of the following components: 30%-50% anhydrous hydrogen fluoride, 30%-42% first organic solvent, and 20%-28% second organic solvent; the first organic solvent is selected from one of polyols, pyridine, dimethyl sulfoxide, and carboxylic acids; the second organic solvent is selected from one of dimethylformamide, dimethylacetamide, N,N-diisopropylethylamine, and N,N-dimethylpropyleneurea; in another embodiment, the inorganic corrosion solution is prepared by mixing a 50% mass concentration ammonium fluoride solution and a 40% mass concentration hydrofluoric acid solution in a volume ratio of 1:1-5. In this embodiment, an inorganic corrosion solution prepared by mixing a 50% mass concentration ammonium fluoride solution and a 40% mass concentration hydrofluoric acid solution in a volume ratio of 1:1 is selected. Immerse the cleaned and dried Z-cut quartz wafer in the inorganic corrosion solution at 50°C for 3 minutes, then rinse with pure water, spin dry, and bake to obtain a pre-corroded quartz wafer;

[0074] S23. Metal coat the pre-corroded quartz wafer through a coating process, and then form a photoresist on the surface of the metal film layer obtained by the metal coating through a spin coating process;

[0075] S24. Expose and develop the quartz wafer with photoresist through ultraviolet exposure technology to expose the metal layer corresponding to the quartz sensor chip 2, and etch and remove the metal layer corresponding to the quartz sensor chip 2 with metal etchant to obtain the developed quartz wafer;

[0076] S25. Prepare the quartz sensor chip 2 on the developed quartz wafer through quartz wet chemical etching process to obtain the quartz sensor wafer 1 (Z-cut quartz wafer with quartz sensor chip 2; as Figure 1 shown, in this embodiment, the number of quartz sensor chips 2 prepared on the used Z-cut quartz wafer is 21;

[0077] Refer to Figure 2 and Figure 3 It can be known that each side wall of the quartz sensor chip 2 has a crystal edge 3, and the crystal edge 3 is located on the same side of the quartz sensor chip 2;

[0078] Completely strip and clean and dry the photoresist and metal film layer on the surface of the quartz sensor wafer 1.

[0079] S3. Refer to Figure 5 and Figure 6 , form a first metal film layer 4 on the quartz sensor wafer 1 through a coating process as a protective layer for the quartz sensor wafer 1. The coating process can be any one of resistance heating evaporation, electron beam evaporation, physical vapor deposition, and magnetron sputtering. In one embodiment, the coating process is magnetron sputtering coating, and the coated layers are a Cr film layer and an Au film layer in sequence. The coating thickness of the Cr film layer is The coating thickness of the Au film layer is In this embodiment, the coating thickness of the Cr film layer is The coating thickness of the Au film layer is

[0080] S4. Refer to Figure 5 and Figure 6 , form a first photoresist 5 on the surface of the first metal film layer 4 through a spin coating process. The spin coating process can be any one of ultrasonic spray coating, electrohydrodynamic spray coating, or gravity suspension coating. The thickness of the first photoresist 5 can be 5 - 10 μm. In this embodiment, ultrasonic spray coating is adopted, and the thickness of the first photoresist 5 is 7 μm;

[0081] S5. Expose the first photoresist 5 of the crystal edge 3 through a side exposure method, including:

[0082] S51. Analyze and measure the morphology of the 21 quartz sensor chips 2 on the quartz sensor wafer 1 in sequence to respectively determine the shape, position, and size of the crystal edge 3 on each quartz sensor chip 2;

[0083] By comparison, it is determined that the positions of the crystal edges 3 of each quartz sensor chip 2 are the same. In this embodiment, it includes: the projections of the crystal edges 3 on the quartz sensor chips 2 located on the same sidewall overlap along the direction parallel to the quartz sensor chips 2, and the projections of the crystal edges 3 on the quartz sensor chips 2 located on the same sidewall overlap along the direction perpendicular to the quartz sensor chips 2;

[0084] By comparison, it is determined that the shapes of the crystal edges 3 at the corresponding positions of each quartz sensor chip 2 are the same. In this embodiment, the cross-sectional shape of the crystal edge 3 is triangular;

[0085] By comparison, it is determined that the sizes of the crystal edges 3 at the corresponding positions of each quartz sensor chip 2 are the same. In this embodiment, it is further determined that the angles between the front side of the crystal edge 3 and the sidewall of the quartz sensor chip 2 are the same, and the angles between the back side of the crystal edge 3 and the sidewall of the quartz sensor chip 2 are the same;

[0086] S52. Determine the front-side exposure angle, the front-side photomask, the back-side exposure angle, and the back-side photomask according to the shape, position, and size of the crystal edge 3 on the quartz sensor chip 2;

[0087] In this embodiment, determining the front-side exposure angle and the back-side exposure angle includes:

[0088] Measure that the angle between the front side of the crystal edge 3 and the first surface is α z , and the angle between the back side of the crystal edge 3 and the first surface is α f , where the first surface is the plane where the quartz sensor chip 2 is located;

[0089] The intersection of the crystal edge 3 and the side of the quartz sensor chip 2 extends along the direction parallel to the first surface and intersects with the first metal layer to form a positive exposure line (on the surface of the first metal layer opposite to the front side of the crystal edge 3) and a negative exposure line (on the surface of the first metal layer opposite to the back side of the crystal edge 3);

[0090] Determine the front-side exposure angle such that the ultraviolet exposure light is vertically downward and overlaps with the positive exposure line, and overlaps with the sharp corner of the crystal edge 3, and does not intersect with the side of the quartz sensor chip 2 close to the back side of the crystal edge 3. If the front-side exposure angle is a range value, the maximum value is selected in this embodiment;

[0091] Determine the back-side exposure angle such that the ultraviolet exposure light is vertically downward and overlaps with the negative exposure line, and overlaps with the sharp corner of the crystal edge 3, and does not intersect with the side of the quartz sensor chip 2 close to the back side of the crystal edge 3. If the back-side exposure angle is a range value, the maximum value is selected in this embodiment;

[0092] In this embodiment, designing the front-side photomask and the back-side photomask includes determining the planar mask patterns of the front side and the back side respectively according to the position, shape, and size of the crystal edge 3;

[0093] The planar mask pattern on the front side is further transformed into a front-side photolithography mask pattern required for front-side exposure according to the front-side exposure angle, and a front-side photolithography mask plate is fabricated based on this pattern.

[0094] The planar mask pattern on the back side is further transformed into a back-side photolithography mask pattern required for back-side exposure according to the back-side exposure angle, and a back-side photolithography mask plate is fabricated based on this pattern.

[0095] In summary, referring to Figure 4 , the settings of the front-side exposure angle and the front-side photolithography mask plate achieve: with the front side of the quartz sensor wafer 1 facing upward, after tilting the front-side exposure angle, covering the front-side photolithography mask plate, the ultraviolet light passing through the front-side photolithography mask plate is directed towards the front side of the crystal edge 3 to expose the first photoresist 5 covering the front side of the crystal edge 3, and the end face of the exposed first photoresist 5 cooperates with the first metal layer to form a positive exposure line.

[0096] The settings of the back-side exposure angle and the back-side photolithography mask plate achieve: with the back side of the quartz sensor wafer 1 facing upward, after tilting the back-side exposure angle, covering the back-side photolithography mask plate, the light passing through the back-side photolithography mask plate is directed towards the back side of the crystal edge 3 to expose the first photoresist 5 covering the back side of the crystal edge 3, and the end face of the exposed first photoresist 5 cooperates with the first metal layer to form a negative exposure line.

[0097] S6. Transfer the exposure pattern of the first photoresist 5 to the first metal film layer 4 to expose the crystal edge 6; in this embodiment, a metal etching solution is used to transfer the photoresist pattern on the side of the quartz sensor chip 2 to the first metal film layer 4 by a metal etching method, so that the side crystal edge 3 of the quartz sensor chip 2 is exposed.

[0098] S7. Eliminate the exposed crystal edge 6 exposed on the side of the quartz sensor wafer 1 by a quartz wet chemical etching method, and then strip and clean and dry all the photoresist and metal film layer on the surface of the quartz sensor wafer 1 to obtain the quartz sensor wafer 1.

[0099] Among them, in this step, the quartz wet chemical etching method uses an etching solution for etching. In some embodiments, the etching solution includes a hydrofluoric acid solution with a mass concentration of 50%, an ammonium bifluoride solution with a mass concentration of 40%, and an organic additive. The volume ratio of the hydrofluoric acid solution, ammonium bifluoride solution, and organic additive is 1:1.5:0.05 - 0.5. The organic additive is at least one of glacial acetic acid, ethanol, isopropyl alcohol, and pyridine. In this embodiment, the etching solution includes a hydrofluoric acid solution with a mass concentration of 50%, an ammonium bifluoride solution with a mass concentration of 40%, and ethanol, and their volume ratio is 1:1.5:0.1. The etching duration is 4 hours. Through the combined action, the etching of the crystal edge 3 preferentially starts from the outermost crystal edge 3, and the crystal edge 3y has the same etching characteristics in all directions, so that by controlling the etching duration, the crystal edge 3 is etched to be flush with the side wall of the corresponding quartz sensor chip 2, the crystal edge 3 on the side wall of the quartz sensor chip 2 is eliminated, and the etching effect of the crystal edge 3 is improved.

[0100] S8. Etch the surface electrode onto the surface of the quartz sensor chip 2 to obtain a quartz sensor device.

[0101] Example 2:

[0102] Embodiment 2 of this application discloses a method for reducing the mechanical coupling error of a quartz sensor device. Similar to the embodiment, the difference is that considering the drilling and etching characteristics on both sides of the crystal edge 3 to solve the problem of the diffusion of the crystal edge 3 etching surface towards the quartz side wall caused by the drilling and etching characteristics on both sides of the crystal edge 3, the determination methods of the positive exposure line and the negative exposure line are different. In this embodiment:

[0103] Define the intersection of the exposed crystal edge 6 and the first metal film layer 4 as the first line 7;

[0104] Define the intersection of the crystal edge 3 and the side surface of the quartz sensor chip 2 as the second line 8;

[0105] The distance between the first line 7 and the second line 8 on the same side of the crystal edge 3 can be 0.8 - 1.2 μm. In this embodiment, it is selected as 1 μm;

[0106] The first line 7 extends along a direction parallel to the first surface and intersects with the first metal layer to form a positive exposure line (on the surface of the first metal layer opposite to the positive side surface of the crystal edge 3) and a negative exposure line (on the surface of the first metal layer opposite to the negative side surface of the crystal edge 3). The third line 9 includes the positive exposure line and the negative exposure line;

[0107] After the first photoresist 5 is exposed, the intersection with the first metal film layer 4 overlaps with the third line 9 to form the corresponding positive exposure line and negative exposure line.

[0108] Experimental data

[0109] Figure 9The picture of the quartz sensor device obtained by processing through the method for reducing the mechanical coupling error of the quartz sensor device described in Embodiment 2. From Figure 9 it can be seen that the sidewall crystal edges of the quartz sensor device have a better etching effect and the sidewall etching flatness is good.

[0110] The embodiments of this specific implementation manner are all preferred embodiments of the present application, and do not limit the protection scope of the present application accordingly. The same parts are denoted by the same reference numerals. Therefore, all equivalent changes made according to the structure, shape, and principle of the present application shall be covered within the protection scope of the present application.

Claims

1. A method for reducing the mechanical coupling error of a quartz sensor device, characterized in that It includes the following steps: Multiple quartz sensor chips (2) are processed on a Z-cut quartz wafer to obtain a quartz sensor wafer (1). Each of the quartz sensor chips (2) has a crystal edge (3) on its side wall; A first metal film layer (4) is formed by coating the quartz sensor wafer (1); A first photoresist (5) is formed on the surface of the first metal film layer (4); The first photoresist (5) on the crystal edge (3) is exposed by a side exposure method; The exposed pattern of the first photoresist (5) is transferred to the first metal film layer (4) to obtain an exposed crystal edge (6); The exposed crystal edge (6) is removed by a quartz wet chemical etching method; The junction between the exposed crystal edge (6) and the first metal film layer (4) is defined as a first line (7); The junction between the crystal edge (3) and the side of the quartz sensor chip (2) is defined as a second line (8); The distance between the first line (7) and the second line (8) on the same side of the crystal edge (3) is 0.8 - 1.2 μm.

2. The method for reducing the mechanical coupling error of a quartz sensor device according to claim 1, characterized in that Exposing the first photoresist (5) on the crystal edge (3) by a side exposure method includes: Determining the positive side exposure angle and the positive side photomask; With the front side of the quartz sensor wafer (1) facing up, after tilting the positive side exposure angle, covering the positive side photomask, and the light passing through the positive side photomask is directed towards the positive side of the crystal edge (3) to expose the first photoresist (5) covering the positive side of the crystal edge (3).

3. The method for reducing the mechanical coupling error of a quartz sensor device according to claim 1, wherein Exposing the first photoresist (5) on the crystal edge (3) by a side exposure method further includes: Determining the negative side exposure angle and the negative side photomask; With the back side of the quartz sensor wafer (1) facing up, after tilting the negative side exposure angle, covering the negative side photomask, and the light passing through the negative side photomask is directed towards the negative side of the crystal edge (3) to expose the first photoresist (5) covering the negative side of the crystal edge (3).

4. The method for reducing the mechanical coupling error of a quartz sensor device according to claim 1, characterized in that, The distance is 1 μm.

5. The method for reducing the mechanical coupling error of a quartz sensor device according to claim 1, wherein The first line (7) extends along the direction parallel to the Z-cut quartz wafer and intersects with the first metal film layer (4) covering the crystal edge (3) to form a third line (9); The junction between the exposed first photoresist (5) and the first metal film layer (4) overlaps with the third line (9).

6. The method for reducing the mechanical coupling error of a quartz sensor device according to claim 1, wherein The first metal film layer (4) is a Cr film layer and an Au film layer in sequence, wherein the coating thickness of the Cr film layer is The coating thickness of the Au film layer is 7. The method for reducing the mechanical coupling error of a quartz sensor device according to claim 1, characterized in that, The thickness of the first photoresist (5) is 5 - 10 μm.

8. The method for reducing the mechanical coupling error of a quartz sensor device according to claim 1, characterized in that, The quartz wet chemical etching method includes etching with an etching solution. The etching solution includes a hydrofluoric acid solution with a mass concentration of 50%, an ammonium bifluoride solution with a mass concentration of 40%, and an organic additive. The volume ratio of the hydrofluoric acid solution, the ammonium bifluoride solution, and the organic additive is 1:1.5:0.05 - 0.5, and the organic additive is at least one of glacial acetic acid, ethanol, isopropyl alcohol, and pyridine.

9. The method for reducing the mechanical coupling error of the quartz sensor device according to claim 8, wherein, The volume ratio of the hydrofluoric acid solution, the ammonium bifluoride solution, and the organic additive is 1:1.5:0.1.

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