A method of processing a crystal resonator wafer

Abstract

The application provides a processing method of a crystal resonator wafer, and the processing method comprises the following steps: obtaining a to-be-processed crystal, cutting the to-be-processed crystal to obtain a cut wafer; performing primary rounding and grinding on the cut wafer to obtain a ground wafer; performing at least three times of polishing on the surface layer of the ground wafer to obtain a polished wafer; polishing the surface layer of the polished wafer to obtain a polished wafer; and performing secondary rounding and grinding on the polished wafer to obtain a target wafer. The surface of the crystal is further smoothed by polishing after multi-stage grinding, so that the resistance and parasitic frequency noise of the finished wafer are reduced; the crystal surface is more smooth by using grinding machines with different precisions for step-by-step grinding, the wafer is prevented from being broken due to excessive internal stress, the process is simple, time is saved, and the cost is relatively low.

Description

Technical Field

[0001] This application relates to the field of crystal processing, and in particular to a method for processing a crystal resonator wafer. Background Technology

[0002] A quartz resonator is a device that utilizes the principle that a quartz crystal resonates due to the inverse piezoelectric effect when the frequency of an electrical signal equals the crystal's natural frequency. It is a core component used for frequency selection and control in fields such as long-distance communication, satellite communication, mobile phones, and global positioning systems. With the rapid development of the internet and smart homes, especially the advent of the 5G era, the application areas of quartz crystal resonators are becoming increasingly broad. Among these components, the quartz crystal resonator crystal itself is the most crucial element.

[0003] With the continuous development of technology, the performance requirements for resonators are becoming increasingly stringent, and low-power, low-noise resonators are the current development trend. The resonant resistance and parasitic frequency of a quartz crystal resonator are closely related to its power consumption and noise. Furthermore, the flatness of the crystal surface is a crucial factor affecting the crystal resistance and parasitic frequency noise. A smooth and flat crystal surface is beneficial for suppressing the fundamental frequency sub-wave, improving the quality factor, mitigating hysteresis, and enhancing operational stability under high and low temperature environments.

[0004] To meet the qualification standards for 100MHz to 150MHz high-frequency fifth overtone quartz crystal resonators, the resistance of the finished crystal must be less than 40Ω and the parasitic frequency noise must be less than -3dB. However, the existing technology is insufficient to produce crystals with sufficiently smooth surfaces, thus failing to meet the qualification standards for high-frequency fifth overtone quartz crystal resonators. Summary of the Invention

[0005] In view of the aforementioned problems, this application is proposed to provide a method for fabricating a crystal resonator wafer that overcomes or at least partially solves the aforementioned problems, for fabricating a quartz crystal resonator wafer, comprising the following steps:

[0006] Obtain the crystal to be processed, and cut the crystal to obtain a cut wafer;

[0007] The cut wafer is rounded and ground once to obtain a ground wafer;

[0008] The surface of the polished wafer is polished at least three times to obtain a polished wafer;

[0009] The surface of the abrasive wafer is polished to obtain a polished wafer;

[0010] The polished wafer is then subjected to secondary rounding and grinding to obtain the target wafer.

[0011] Further, the steps of obtaining the crystal to be processed and cutting the crystal to obtain a cut wafer include:

[0012] The crystal to be processed is cut using an AT-type cutting machine.

[0013] Further, the steps of rounding and grinding the cut wafer to obtain a ground wafer include:

[0014] Using a crystal rounding machine, the cut wafer is rounded once to obtain a rounded wafer, the diameter of which is larger than the diameter of the target wafer;

[0015] The first-rounded wafer is ground once, wherein the two grinding platforms are perpendicular to the optical axis of the wafer, to obtain the ground wafer.

[0016] Further, the step of grinding the surface layer of the polished wafer at least three times to obtain the polished wafer includes:

[0017] The surface of the polished wafer is first polished to obtain a first-polished wafer;

[0018] The surface of the first-polished wafer is then polished a second time to obtain a second-polished wafer.

[0019] The surface of the secondary polished wafer is then polished a third time to obtain a tertiary polished wafer.

[0020] Further, the step of performing a first grinding on the surface of the first-ground wafer to obtain a first-ground wafer includes:

[0021] The surface of the first-stage polished wafer is polished using a 9B polishing machine to obtain a first-stage polished wafer.

[0022] Further, the step of performing a second polishing on the surface of the first-polished wafer to obtain a second-polished wafer includes:

[0023] The surface of the first-polished wafer is polished using a 6B polishing machine to obtain a second-polished wafer.

[0024] Further, the step of performing a third polishing on the surface of the second polished wafer to obtain a third polished wafer includes:

[0025] The surface of the secondary polishing wafer is polished using a 4B polishing machine to obtain a tertiary polishing wafer.

[0026] Further, the step of polishing the surface layer of the polished wafer to obtain a polished wafer includes:

[0027] The surface of the three-stage polished wafer is polished using a 4B polishing machine to obtain the polished wafer.

[0028] Further, the steps of performing secondary rounding and grinding on the polished wafer to obtain the target wafer include:

[0029] The polished wafer is then rounded a second time to obtain a rounded wafer.

[0030] The secondary rounded wafer is subjected to secondary grinding, with the two grinding platforms perpendicular to the optical axis of the wafer, to obtain the target wafer.

[0031] Furthermore, the cutting angle of the cutting machine is 35°22'~35°24', and the cutting thickness is 0.19mm~0.21mm.

[0032] This application has the following advantages:

[0033] In the embodiments of this application, addressing the problem of insufficient surface flatness of quartz crystal resonator wafers processed by existing manufacturing processes, this application provides a solution for multi-stage grinding of the crystal, specifically: "Obtaining a crystal to be processed, cutting the crystal to obtain a cut wafer; performing a rounding and grinding process on the cut wafer to obtain a ground wafer; grinding the surface of the ground wafer at least three times to obtain a polished wafer; polishing the surface of the polished wafer to obtain a polished wafer; and performing a second rounding and grinding process on the polished wafer to obtain the target wafer." By polishing after multi-stage grinding of the crystal, the surface of the crystal is further flattened, reducing the resistance and parasitic frequency noise of the finished wafer. Attached Figure Description

[0034] To more clearly illustrate the technical solution of this application, the drawings used in the description of this application will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0035] Figure 1 This is a flowchart of a method for fabricating a crystal resonator wafer according to an embodiment of this application;

[0036] Figure 2 This is a schematic diagram of a crystal resonator wafer fabrication method provided in an embodiment of this application.

[0037] The reference numerals in the accompanying drawings are as follows:

[0038] 1. Wafer diameter; 2. Spacing between the two platforms. Detailed Implementation

[0039] To make the objectives, features, and advantages of this application more apparent and understandable, the application will be further described in detail below with reference to the accompanying drawings and specific embodiments. Obviously, the described embodiments are only some, not all, of the embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0040] It should be noted that, without conflict, the embodiments and features in the embodiments of this application can be combined with each other. This application is used to manufacture resonator chips with sufficiently smooth surfaces to reduce the resistance and parasitic noise of the chips. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0041] The inventors discovered through analysis of existing technologies that existing wafer thinning methods include wet etching and polishing. Wet etching typically involves immersing the wafer in an etching solution for etching, and the degree of etching needs to be controlled, so multiple immersion etching processes are required, which is time-consuming and inefficient. Polishing is less time-consuming and more efficient than wet etching, but the wafer is inevitably subjected to internal stress generated during polishing, which can cause the wafer to break. Therefore, polishing the wafer in stages can reduce the generation of internal stress and reduce the risk of wafer breakage.

[0042] Reference Figure 1 This application illustrates a method for fabricating a crystal resonator wafer, the method comprising the following steps:

[0043] S1. Obtain the crystal to be processed, and cut the crystal to be processed to obtain a cut wafer.

[0044] S2. The cut wafer is rounded and ground once to obtain a ground wafer.

[0045] S3. The surface layer of the first-time polished wafer is polished at least three times to obtain a polished wafer.

[0046] S4. Polish the surface of the grinding wafer to obtain a polished wafer.

[0047] S5. Perform secondary rounding and grinding on the polished wafer to obtain the target wafer.

[0048] In the embodiments of this application, the crystal to be processed is cut into thin slices in advance and then rounded and ground once. The rounded and ground wafer is ground at least three times with different finenesses, so that the wafer can still maintain the roundness of the platform and gradually reduce and be ground flat.

[0049] In the embodiments of this application, addressing the problem of insufficient surface flatness of quartz crystal resonator wafers processed by existing manufacturing processes, this application provides a solution for multi-stage grinding of the crystal, specifically: "Obtaining a crystal to be processed, cutting the crystal to obtain a cut wafer; performing a rounding and grinding process on the cut wafer to obtain a ground wafer; grinding the surface of the ground wafer at least three times to obtain a polished wafer; polishing the surface of the polished wafer to obtain a polished wafer; and performing a second rounding and grinding process on the polished wafer to obtain the target wafer." By polishing after multi-stage grinding of the crystal, the surface of the crystal is further flattened, reducing the resistance and parasitic frequency noise of the finished wafer.

[0050] The following will further describe a method for fabricating a crystal resonator wafer in this exemplary embodiment.

[0051] In the embodiments of this application, as in step S1, a crystal to be processed is obtained, and the crystal to be processed is cut to obtain a cut wafer. This requires obtaining the thickness and angle of the crystal to be processed, determining the cutting abrasive material for the cutting machine, and then using the cutting machine to cut the crystal to be processed.

[0052] In the embodiments of this application, as in step S2, the cut wafer is rounded and ground once to obtain a ground wafer; wherein, the cut wafer is ground into a circular wafer by a crystal rounding machine, and the two grinding platforms are perpendicular to the optical axis of the wafer. The optical axis of the wafer is the direction in which light does not produce birefringence in the anisotropic wafer, and is called the optical axis of this wafer.

[0053] Furthermore, if the wafer is of another shape, such as a rectangle, in S2 the crystal to be processed should be pre-cut into a rectangle, but with a volume slightly larger than the final target volume, to avoid the wafer volume becoming smaller than the final target volume during subsequent grinding. The same operation applies if the wafer is of another shape.

[0054] In the embodiments of this application, as in step S3, the surface of the first-grind wafer is polished at least three times. The multi-stage polishing can prevent the wafer from breaking due to excessive internal stress. The at least three polishing operations use double-sided polishing machines of different precision, with the precision increasing sequentially, such as 9B double-sided polishing machine, 6B double-sided polishing machine, 4B double-sided polishing machine, etc., to finally obtain the polished wafer.

[0055] Furthermore, the types of polishing machines and polishing slurries required for manufacturing different types of wafers, such as high-frequency third-order overtone quartz crystal resonator wafers and high-frequency fifth-order overtone quartz crystal resonator wafers, are also different. The types of polishing machines and polishing slurries are determined according to the type of wafer to be manufactured.

[0056] The required cutting angle, wafer size, and thickness reduction from grinding and polishing vary depending on the type of wafer being manufactured. These parameters must be determined based on the specific type of wafer being produced.

[0057] Furthermore, the volume of the first-stage polished wafer becomes smaller and smaller, and the smoothness of the wafer surface becomes higher and higher.

[0058] In the embodiments of this application, such as step S4, the composition and ratio of the polishing liquid are determined, a polishing machine, such as a 4B polishing machine, is selected, and the surface of the grinding wafer is polished to obtain a polished wafer; the purpose is to further improve the smoothness of the crystal surface.

[0059] In the embodiments of this application, as in step S5, the polished wafer undergoes secondary rounding and grinding to obtain the target wafer. The final thickness and shape of the target wafer are obtained, and the polished wafer obtained in step S4 undergoes final rounding and grinding to obtain the desired target wafer. The polished wafer undergoes secondary rounding and grinding of both end platforms, ultimately determining the size and shape of the wafer while preserving the smoothness of the wafer surface. If the size and shape of the wafer are determined before polishing, it is not only easy to alter the shape of the wafer but also easy to result in incomplete polishing, leading to insufficient surface smoothness.

[0060] In the embodiments of this application, the transfer of the aforementioned wafer between different machines can be done manually or by machine, and no limitation is made herein.

[0061] As an example of fabricating a high-frequency fifth-order overtone quartz crystal resonator wafer according to this application, the steps are as follows:

[0062] The crystal to be processed is subjected to AT-type cutting using a cutting machine to obtain a cut wafer; the cutting angle of the cutting machine is 35°22'~35°24', the cutting thickness is 0.19mm~0.21mm; the cutting abrasive is 1200# silicon carbide.

[0063] like Figure 2 The cut wafer is rounded once using a crystal rounding machine to obtain a rounded wafer with a diameter of 7.98 mm to 8.02 mm.

[0064] The first-rounded wafer is ground once, with the two grinding platforms perpendicular to the optical axis of the wafer, to obtain the first-ground wafer; the distance between the two grinding platforms is 6.98mm to 7.02mm.

[0065] The surface of the first-stage polishing wafer is polished using a 9B polishing machine, reducing the surface thickness of the first-stage polishing wafer by 0.04mm to 0.06mm to obtain a first-stage polished wafer. The polishing fluid of the 9B polishing machine is 1500# silicon carbide and water, with a silicon carbide to water ratio of 2:3.

[0066] The surface of the first-stage polishing wafer is polished using a 6B polishing machine, reducing the surface thickness of the first-stage polishing wafer by 0.02mm to 0.03mm to obtain a second-stage polishing wafer. The polishing slurry used in the 6B polishing machine is 2000# silicon carbide and water. The ratio of silicon carbide to water is 2:3.

[0067] The surface of the secondary polishing wafer is polished using a 4B polishing machine, reducing the surface thickness of the secondary polishing wafer by 0.015mm to 0.02mm to obtain a tertiary polishing wafer. The polishing fluid of the 4B polishing machine is 4000# white corundum and water, with the ratio of white corundum to water being 2:3.

[0068] The surface of the three-stage polishing wafer is polished using a 4B polishing machine, reducing the surface thickness of the wafer by 0.01mm to 0.015mm to obtain the polished wafer. The polishing liquid of the 4B polishing machine consists of 9000# cerium oxide and water, with a cerium oxide to water ratio of 1:1.

[0069] The polished wafer is then rounded a second time to obtain a rounded wafer; the diameter of the rounded wafer is 4.48 mm to 4.52 mm.

[0070] The secondary rounded wafer is subjected to secondary grinding, and the distance between the two platforms formed by grinding is 3.98mm to 4.02mm, thus obtaining the target wafer.

[0071] The following is Example 1 of this application, which describes the steps for fabricating a high-frequency fifth-order overtone quartz crystal resonator wafer:

[0072] The crystal to be processed is cut using an AT-type cutting machine to obtain a cut wafer; the cutting angle of the cutting machine is 35°23', the cutting thickness is 0.20mm; the cutting abrasive is 1200# silicon carbide.

[0073] like Figure 2 A crystal rounding machine is used to round the cut wafer once to obtain a rounded wafer with a diameter of 8.0 mm.

[0074] The first-rounded wafer is ground once, with the two grinding platforms perpendicular to the optical axis of the wafer, to obtain the first-ground wafer; the distance between the two grinding platforms is 7.0 mm.

[0075] The surface of the first-stage polishing wafer is polished using a 9B polishing machine, reducing the surface thickness of the first-stage polishing wafer by 0.05 mm to obtain a first-stage polished wafer. The polishing fluid of the 9B polishing machine is 1500# silicon carbide and water, with a silicon carbide to water ratio of 2:3.

[0076] The surface of the first-stage polishing wafer is polished using a 6B polishing machine, reducing the surface thickness by 0.025 mm to obtain a second-stage polishing wafer. The polishing slurry used in the 6B polishing machine is 2000# silicon carbide and water, with a silicon carbide to water ratio of 2:3.

[0077] The surface of the secondary polishing wafer is polished using a 4B polishing machine, reducing the surface thickness of the secondary polishing wafer by 0.018 mm to obtain a tertiary polishing wafer. The polishing fluid of the 4B polishing machine is 4000# white corundum and water, with the ratio of white corundum to water being 2:3.

[0078] The surface of the three-stage polished wafer is polished using a 4B polishing machine, reducing the surface thickness of the wafer by 0.013 mm to obtain the polished wafer. The polishing slurry of the 4B polishing machine consists of 9000# cerium oxide and water, with a cerium oxide to water ratio of 1:1.

[0079] The polished wafer is then rounded a second time to obtain a rounded wafer; the diameter of the rounded wafer is 4.5 mm.

[0080] The secondary rounded wafer is subjected to secondary grinding, with the two grinding platforms perpendicular to the optical axis of the wafer, and the distance between the two grinding platforms is 4.0 mm, thus obtaining the target wafer.

[0081] The following is Example 2 of this application, which describes the steps for fabricating a high-frequency fifth-order overtone quartz crystal resonator wafer:

[0082] The crystal to be processed is processed using an AT-type cutting machine to obtain a cut wafer; the cutting angle of the cutting machine is 35°22', the cutting thickness is 0.19mm; the cutting abrasive is 1200# silicon carbide.

[0083] like Figure 2 The cut wafer is rounded once using a crystal rounding machine to obtain a rounded wafer with a diameter of 7.98 mm.

[0084] The first-rounded wafer is ground once, with the two grinding platforms perpendicular to the optical axis of the wafer, to obtain the first-ground wafer; the distance between the two grinding platforms is 6.98 mm.

[0085] The surface of the first-stage polishing wafer is polished using a 9B polishing machine, reducing the surface thickness of the first-stage polishing wafer by 0.04 mm to obtain a first-stage polished wafer. The polishing fluid of the 9B polishing machine is 1500# silicon carbide and water, with a silicon carbide to water ratio of 2:3.

[0086] The surface of the first-stage polishing wafer is polished using a 6B polishing machine, reducing the surface thickness of the first-stage polishing wafer by 0.02 mm to obtain a second-stage polishing wafer. The polishing slurry used in the 6B polishing machine is 2000# silicon carbide and water. The ratio of silicon carbide to water is 2:3.

[0087] The surface of the secondary polishing wafer is polished using a 4B polishing machine, reducing the surface thickness of the secondary polishing wafer by 0.015 mm to obtain a tertiary polishing wafer. The polishing fluid of the 4B polishing machine is 4000# white corundum and water, with the ratio of white corundum to water being 2:3.

[0088] The surface of the three-stage polished wafer is polished using a 4B polishing machine, reducing the surface thickness of the wafer by 0.01 mm to obtain the polished wafer. The polishing slurry of the 4B polishing machine consists of 9000# cerium oxide and water, with a cerium oxide to water ratio of 1:1.

[0089] The polished wafer is then rounded a second time to obtain a rounded wafer; the diameter of the rounded wafer is 4.48 mm.

[0090] The secondary rounded wafer is subjected to secondary grinding, with the two grinding platforms perpendicular to the optical axis of the wafer. The distance between the two grinding platforms is 3.98 mm, thus obtaining the target wafer.

[0091] The following is Example 3 of this application, outlining the steps for fabricating a high-frequency fifth-order overtone quartz crystal resonator wafer:

[0092] The crystal to be processed is processed using an AT-type cutting machine to obtain a cut wafer; the cutting angle of the cutting machine is 35°24', the cutting thickness is 0.21mm; the cutting abrasive is 1200# silicon carbide.

[0093] like Figure 2 The cut wafer is rounded once using a crystal rounding machine to obtain a rounded wafer with a diameter of 8.02 mm.

[0094] The first-rounded wafer is ground once, with the two grinding platforms perpendicular to the optical axis of the wafer's Z-axis, to obtain the first-rounded wafer; the distance between the two grinding platforms is 7.02 mm.

[0095] The surface of the first-stage polished wafer is polished using a 9B polishing machine, reducing the surface thickness of the first-stage polished wafer by 0.06 mm to obtain a first-stage polished wafer. The polishing fluid of the 9B polishing machine is 1500# silicon carbide and water, with a silicon carbide to water ratio of 2:3.

[0096] The surface of the first-stage polishing wafer is polished using a 6B polishing machine, reducing the surface thickness by 0.03 mm to obtain a second-stage polishing wafer. The polishing slurry used in the 6B polishing machine is 2000# silicon carbide and water, with a silicon carbide to water ratio of 2:3.

[0097] The surface of the secondary polishing wafer is polished using a 4B polishing machine, reducing the surface thickness of the secondary polishing wafer by 0.02 mm to obtain a tertiary polishing wafer. The polishing fluid of the 4B polishing machine is 4000# white corundum and water, with the ratio of white corundum to water being 2:3.

[0098] The surface of the three-stage polished wafer is polished using a 4B polishing machine, reducing the surface thickness of the wafer by 0.015 mm to obtain the polished wafer. The polishing slurry of the 4B polishing machine consists of 9000# cerium oxide and water, with a cerium oxide to water ratio of 1:1.

[0099] The polished wafer is then rounded a second time to obtain a rounded wafer; the diameter of the rounded wafer is 4.52 mm.

[0100] The secondary rounded wafer is subjected to secondary grinding, with the two grinding platforms perpendicular to the optical axis of the wafer. The distance between the two grinding platforms is 4.02 mm, thus obtaining the target wafer.

[0101] Although preferred embodiments of the present application have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of the embodiments of the present application.

[0102] Finally, it should be noted that in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or terminal device that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or terminal device. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or terminal device that includes said element.

[0103] The above provides a detailed description of a crystal resonator wafer processing method provided in this application. Specific examples have been used to illustrate the principles and implementation methods of this application. The description of the above embodiments is only for the purpose of helping to understand the method and core ideas of this application. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of this application. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A method for fabricating a crystal resonator wafer, used for fabricating a quartz crystal resonator wafer, characterized in that, Includes the following steps: Obtain the crystal to be processed, and cut the crystal to obtain a cut wafer; The cut wafer is rounded once and ground to obtain a ground wafer; wherein, a crystal rounding machine is used to round the cut wafer once to obtain a rounded wafer, the diameter of the rounded wafer being larger than the diameter of the target wafer; the rounded wafer is then ground once; wherein, the two grinding platforms are perpendicular to the optical axis of the wafer to obtain the ground wafer. The surface of the polished wafer is polished at least three times to obtain a polished wafer; The surface of the abrasive wafer is polished to obtain a polished wafer; The polished wafer is subjected to secondary rounding and grinding to obtain the target wafer; wherein, the polished wafer is subjected to secondary rounding to obtain a secondary rounded wafer; the secondary rounded wafer is subjected to secondary grinding to obtain the target wafer, wherein the two grinding platforms are perpendicular to the optical axis of the wafer.

2. The method for fabricating a crystal resonator wafer according to claim 1, characterized in that, The steps of obtaining the crystal to be processed and cutting the crystal to obtain a cut wafer include: The crystal to be processed is cut using an AT-type cutting machine.

3. The method for fabricating a crystal resonator wafer according to claim 1, characterized in that, The step of grinding the surface layer of the polished wafer at least three times to obtain the polished wafer includes: The surface of the polished wafer is first polished to obtain a first-polished wafer; The surface of the first-polished wafer is then polished a second time to obtain a second-polished wafer. The surface of the secondary polished wafer is then polished a third time to obtain a tertiary polished wafer.

4. The method for fabricating a crystal resonator wafer according to claim 3, characterized in that, The step of performing a first grinding on the surface of the first-ground wafer to obtain a first-ground wafer includes: The surface of the first-stage polished wafer is polished using a 9B polishing machine to obtain a first-stage polished wafer.

5. The method for fabricating a crystal resonator wafer according to claim 3, characterized in that, The step of performing a second polishing on the surface of the first-polished wafer to obtain a second-polished wafer includes: The surface of the first-polished wafer is polished using a 6B polishing machine to obtain a second-polished wafer.

6. The method for fabricating a crystal resonator wafer according to claim 3, characterized in that, The step of performing a third polishing on the surface of the second-polished wafer to obtain a third-polished wafer includes: The surface of the secondary polishing wafer is polished using a 4B polishing machine to obtain a tertiary polishing wafer.

7. The method for fabricating a crystal resonator wafer according to claim 1, characterized in that, The step of polishing the surface of the grinding wafer to obtain a polished wafer includes: The surface of the three-stage polished wafer is polished using a 4B polishing machine to obtain the polished wafer.

8. The method for fabricating a crystal resonator wafer according to claim 2, characterized in that, The cutting angle is 35°22'~35°24', and the cutting thickness is 0.19mm~0.21mm.

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