Preparation method of surface-mounted temperature compensation crystal oscillator and surface-mounted temperature compensation crystal oscillator

Abstract

The invention relates to the technical field of crystal oscillators, and provides a preparation method of a surface-mounted temperature compensation crystal oscillator and the surface-mounted temperature compensation crystal oscillator, and the preparation method comprises the steps: obtaining the specification parameter information and processing parameter information of an original wafer; determining the area of an electrode, forming an electrode on the wafer, packaging the electrode to obtain an original crystal, and testing the original crystal to obtain a test result; the original crystals with different test results are selected for manufacturing crystal oscillators, the manufactured crystal oscillators are compensated and verified, and the crystal oscillator temperature precision under the original crystals in different states is obtained; enabling the crystal oscillator temperature precision to correspond to the crystal temperature curve, determining an optimal crystal curve, and obtaining an updated crystal according to the specification parameter information of the updated original wafer; and testing and updating the crystal until the preset precision is reached so as to obtain the optimal specification parameter of the crystal. And the optimal crystal specification parameters can be determined by corresponding to the crystal temperature curve, so that the limitation of precision can be broken through, and the high-precision requirement can be met.

Description

Technical Field

[0001] The present invention relates to the technical field of crystal oscillators, and in particular to a preparation method of a surface-mount temperature-compensated crystal oscillator and a surface-mount temperature-compensated crystal oscillator. Background Art

[0002] A surface-mount temperature compensated crystal oscillator (TCXO) is a crystal oscillator that maintains the output frequency of the crystal within a certain accuracy range through a certain compensation method within a certain temperature range. It has the characteristics of low power consumption, high accuracy, and good stability. It is used in military electronic equipment and military equipment for frequency source control.

[0003] The accuracy of current surface-mount temperature-compensated crystal oscillators is usually between ±0.5ppm and ±2.0ppm, which is difficult to meet the needs of high-precision scenarios. In addition, the related technologies are limited by the combined influence of the crystal oscillator base structure and the compensation system algorithm, making it difficult to effectively improve the accuracy. Summary of the invention

[0004] The present invention provides a preparation method of a surface-mount temperature-compensated crystal oscillator and a surface-mount temperature-compensated crystal oscillator, which are used to solve the defect of limited precision improvement in the prior art.

[0005] A first aspect of the present invention provides a method for preparing a surface-mount temperature-compensated crystal oscillator, comprising the following steps: Obtaining specification parameter information and processing parameter information of the original wafer; Determining the electrode area, forming the electrode on the wafer and packaging it to obtain an original crystal, and testing the original crystal to obtain a test result; Selecting the original crystals with different test results to respectively manufacture crystal oscillators, performing primary compensation, secondary compensation and verification on the prepared crystal oscillators, and obtaining the crystal oscillator temperature accuracy of the original crystals in different states; By matching the crystal oscillator temperature accuracy with the crystal temperature curve, the best crystal curve and a plan for improving the chip specification parameters are determined, and the specification parameter information of the original chip is updated according to the plan for improving the chip specification parameters to obtain an updated crystal; The updated crystal is tested until a preset accuracy is achieved to obtain the specification parameters of the best crystal.

[0006] According to the method for preparing a surface-mount temperature-compensated crystal oscillator provided by the present invention, the specification parameter information includes chip specifications, chip angles and electrode areas, and corrosion frequency.

[0007] According to the method for preparing a surface-mount temperature-compensated crystal oscillator provided by the present invention, the wafer corrosion coefficient is 0.8-1.3.

[0008] According to the method for preparing a surface-mount temperature-compensated crystal oscillator provided by the present invention, the wafer angle is 35°3′~35°16′.

[0009] According to the method for preparing a surface-mount temperature-compensated crystal oscillator provided by the present invention, the preset accuracy is ±0.1ppm.

[0010] According to the method for preparing a surface-mount temperature-compensated crystal oscillator provided by the present invention, electrodes are formed on a wafer and packaged to obtain an original crystal, and the original crystal is tested to obtain a test result, which specifically includes the following steps: Electrodes are formed on the original crystal by using sputtering coating and etching processes, and the original crystal is formed by SMD packaging. The original crystal is tested to obtain a frequency-temperature curve of the original crystal.

[0011] According to the preparation method of the surface-mount temperature-compensated crystal oscillator provided by the present invention, the crystal, capacitor and chip are assembled together in a base, and secondary packaging is performed to obtain the crystal oscillator.

[0012] According to the method for preparing a surface-mount temperature-compensated crystal oscillator provided by the present invention, the best crystal curve is determined according to the correspondence between the crystal oscillator accuracy and the crystal temperature curve, comprising the following steps: By analyzing the frequency-temperature curve, the crystal oscillator accuracy of crystals with different specification parameters is made to correspond to it, and the one with the highest accuracy is taken as the best crystal curve.

[0013] According to the method for preparing a surface-mount temperature-compensated crystal oscillator provided by the present invention, the electrode area is 0.75×0.75~1.3×1 mm.

[0014] A second aspect of the present invention provides a surface-mount temperature-compensated crystal oscillator, comprising: A base, wherein an inner cavity is formed in the base, a welding ring is formed around the outer edge of the inner cavity, and a grounding pad is formed inside the inner cavity; A crystal, the crystal is arranged in the ground pad, and the crystal is bonded to the ground pad, and a chip is mounted on the crystal; A first capacitor and a second capacitor, wherein the first capacitor and the second capacitor are arranged at an interval, and one end of the first capacitor and the second capacitor are both connected to the ground pad, the other end of the first capacitor is connected to a power supply, and the other end of the second capacitor is connected to a voltage control terminal of the chip; Wherein, the specifications of the crystal are prepared by the preparation method of the surface-mount temperature-compensated crystal oscillator described in any one of the above items.

[0015] The present invention provides a method for preparing a surface-mount temperature-compensated crystal oscillator. The crystal oscillator can obtain the crystal oscillator temperature accuracy under different states through two compensations and verifications, and can determine the specification parameters of the best crystal by corresponding to the crystal temperature curve, so as to break through the accuracy limitation and meet the high-precision requirements.

[0016] Furthermore, the two capacitors in the surface-mount temperature-compensated crystal oscillator can improve the stability of the product output frequency, reduce the impact of the power supply, improve the product phase noise index, and better play the chip performance. The chip, capacitor, and crystal are simultaneously encapsulated inside the crystal oscillator, which can make the output frequency of the crystal oscillator more stable, reduce the deviation caused by other system equipment such as the power supply, and put the product in an inert gas protection, thereby improving reliability. Designing the chip angle, external dimensions, electrode area, and corrosion frequency during crystal production can make the frequency temperature stability of the crystal oscillator higher. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0018] Figure 1 It is a schematic flow chart of the method for preparing a surface-mount temperature-compensated crystal oscillator provided in the first aspect of the present invention.

[0019] Figure 2 It is a schematic diagram of the structure of the surface-mount temperature-compensated crystal oscillator provided by the second aspect of the present invention.

[0020] Figure 3 The invention provides a schematic diagram of the connection process of the surface-mount temperature-compensated crystal oscillator.

[0021] Reference numerals: 10. Base; 11. Welding ring; 12. Inner cavity; 13. Ground pad; 14. Bottom pad; 20. Crystal; 30. Chip; 40. First capacitor; 50. Second capacitor. DETAILED DESCRIPTION

[0022] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the drawings of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0023] In the description of the embodiments of the present invention, it should be noted that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the embodiments of the present invention and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore cannot be understood as limitations on the embodiments of the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance.

[0024] In the description of the embodiments of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "connected" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in the embodiments of the present invention can be understood according to specific circumstances.

[0025] In the embodiments of the present invention, unless otherwise clearly specified and limited, the first feature being "above" or "below" the second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, the first feature being "above", "above" and "above" the second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. The first feature being "below", "below" and "below" the second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0026] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the embodiment of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0027] In the related art, the methods for improving the accuracy of surface-mount temperature-compensated crystal oscillators include: selecting high-quality crystal materials, adopting temperature-compensated circuit design, and improving packaging technology to reduce the impact of temperature on crystal oscillator performance. The above methods are difficult to achieve a stable improvement in the accuracy of surface-mount temperature-compensated crystal oscillators and difficult to meet high-precision requirements.

[0028] Combine the following Figure 1 The present invention provides a method for preparing a surface-mount temperature-compensated crystal oscillator, comprising the following steps: Step S100: Obtain specification parameter information and processing parameter information of the original wafer.

[0029] Specifically, based on the theory of the influence of chip size, angle, electrode area, and corrosion frequency on accuracy, the approximate specification range of the chip is determined, and the processing technology and processing requirements are designed according to the approximate specification range to obtain the initial raw chip, and further preparation is carried out based on the raw chip.

[0030] In specific settings, the specification parameter information includes the size specifications of the crystal 20 , the angle of the crystal 20 and the electrode area, and the processing parameter information includes the processing method of the crystal 20 .

[0031] Theoretically, the shape of the chip is a rectangular piece. If the length of the rectangular piece is not properly selected, the even harmonics of the bending vibration frequency generated by its length will be coupled with the main vibration, or the odd harmonics generated by the surface shear vibration will be coupled with the main vibration. When coupling occurs, parasitics will also be generated. In order to avoid the coupling of thickness shear vibration and surface shear vibration, it is necessary to determine the ratio of width to thickness. Specifically, the thickness t of the quartz chip is determined by the formula t=nKƒ / ƒ, where n is the number of overtone harmonics, Kƒ≈1670kHz·mm, and ƒ is the frequency of the quartz chip. Therefore, the parasitic performance can be improved by reasonably designing the length L and width W of the rectangular piece, thereby improving the jump point and compensation accuracy.

[0032] The angle of the crystal 20 affects its frequency-temperature characteristics (i.e., temperature coefficient). When the temperature changes, the frequency of the crystal 20 will change. Correctly selecting the cutting angle can optimize the temperature compensation curve so that the crystal oscillator can control the frequency within a set range within a specific temperature range and keep it stable. For example, the temperature coefficient of the AT-cut crystal 20 is relatively small, which is suitable for most temperature compensation needs.

[0033] When the electrode size is large, the disadvantage is that parasitics are easily generated, which will cause the electrode to be close to the base 10. When the product vibrates, it is easy to be transmitted to the base 10 and reflected, thereby weakening the main vibration, increasing consumption, and reducing the Q value. The advantage is that the resistance is small and it is easy to oscillate. When the electrode size is small, the advantage is small parasitics, and the disadvantage is that the resistance is large and it is not easy to oscillate. At the same time, the circuit matching problem must also be considered.

[0034] When processing the crystal 20, the chip corrosion frequency and corrosion coefficient affect the thickness of the electrode to a certain extent. The increase in electrode film thickness will increase the aging of the crystal 20 and may generate or increase parasitics. Too much electrode film thickness will increase the dynamic resistance caused by the mechanical load caused by the metal film and even cause the quartz chip to stop vibrating and other negative effects. Too thin film thickness will affect conductivity. It can be seen that in the preparation process of the surface-mount temperature-compensated crystal oscillator, the control of its specification parameter information and processing parameter information can effectively achieve the improvement of accuracy.

[0035] Step S200, determining the electrode area, forming electrodes on a wafer and packaging to obtain an original crystal, and testing the original crystal to obtain a test result.

[0036] Specifically, electrodes are formed on the wafer through conventional processes to ensure that the area of ​​the electrodes after formation is a certain area, thereby achieving control over the electrode area. After the electrodes are connected on the wafer, the original crystal structure is formed, and specific tests are performed through the temperature test system.

[0037] During the test, a high-precision frequency meter, temperature control box (temperature environment test equipment), and temperature sensor are used to measure the original crystal to obtain the frequency-temperature curve of the original crystal. This method of detection can detect the temperature curve of the original crystal and output the test results.

[0038] In a specific configuration, sputtering coating and etching processes are used to form electrodes on the original crystal, and the original crystal is tested after packaging to obtain a frequency-temperature curve of the original crystal.

[0039] Step S300, selecting original crystals with different test results to respectively manufacture crystal oscillators, performing primary compensation, secondary compensation and verification on the manufactured crystal oscillators, and obtaining the crystal oscillator temperature accuracy under the original crystals in different states.

[0040] When measuring, multiple original crystals are selected. The specifications of the multiple original crystals are different. The original crystals with differences are selected and the crystal oscillators are manufactured accordingly. The multiple crystal oscillators manufactured are compensated by the compensation system, and the temperature accuracy of the crystal oscillators is obtained.

[0041] Specifically, a secondary temperature compensation model is provided in the compensation system, and the secondary temperature compensation model is used to further correct the nonlinear part to improve the frequency stability of the surface-mounted temperature-compensated crystal oscillator, and can achieve accurate precision testing. Furthermore, the temperature compensation model in this embodiment is obtained by training with data collected multiple times, and the trained model can perform secondary compensation for the nonlinear part, and the primary compensation is achieved through the compensation circuit, and the primary compensation is used to compensate for the deviation of the linear part. The frequency stability of the crystal oscillator can be made higher through primary compensation and secondary compensation. Of course, the existing related models can be used to achieve compensation for the secondary temperature compensation model, such as using a software algorithm to model the relationship between temperature and frequency, and the output frequency of the oscillator can be dynamically adjusted according to the temperature change to achieve compensation.

[0042] After two compensations, the crystal oscillator frequency tends to be stable. At this time, the crystal oscillator frequency is measured by a high-precision frequency meter to obtain an accurate measurement of the output frequency of the surface-mount temperature compensated crystal oscillator and output a specific accuracy result.

[0043] In a specific embodiment, the frequency drift caused by the change of ambient temperature is compensated by changing the load capacitance in the oscillation loop of the crystal oscillator so that it changes with the temperature.

[0044] The original crystal forms a crystal oscillator after being connected to the oscillation circuit. The compensation system is provided with a load capacitor connected to the oscillation circuit. By changing the size of the load capacitor, the frequency drift caused by the ambient temperature can be compensated, thereby achieving a primary compensation for the crystal oscillator.

[0045] That is, by connecting the load capacitor in the oscillation loop of the crystal oscillator, the primary compensation of the frequency can be achieved, and after the primary compensation, the secondary compensation of the frequency can be achieved through the secondary temperature compensation model, so as to improve the stability of the output frequency and improve the accuracy of precision detection.

[0046] It is understandable that the compensation accuracy can be used to determine the qualified rate of crystal oscillators of different specifications that achieve the preset accuracy, and then the specifications can be improved through data analysis.

[0047] Step S400, the crystal oscillator temperature accuracy is matched with the crystal temperature curve, the best crystal curve and the scheme for improving the chip specification parameters are determined, and the specification parameter information of the original chip is updated according to the scheme for improving the chip specification parameters to obtain an updated crystal.

[0048] Through step S300, the accuracy results of different crystal oscillators with different specifications can be obtained, and by matching the accuracy results with the corresponding crystal temperature curves, a curve corresponding to the temperature curve and the corresponding accuracy can be obtained.

[0049] In a specific example, by analyzing the frequency-temperature curve, the crystal oscillator accuracy of crystals under different specification parameters is made to correspond thereto, and the one with the highest accuracy is used as the best crystal curve. That is, among different crystals with specification differences, the accuracy results after measurement have corresponding crystal curves, and the one with the highest accuracy is selected as the best crystal, and a solution for improving the chip specifications is obtained according to the specification differences between different crystals, and the specification parameters of the original crystal are adjusted according to the solution, and an updated crystal is obtained.

[0050] For example, a crystal with the highest test accuracy pass rate is selected, and the crystal dimensions, crystal angles, and electrode areas are used as references to reprocess the original crystal. Specifically, when processing the original wafer, the crystal dimensions, crystal angles, and electrode areas are referenced to process the original wafer to obtain a newer crystal.

[0051] Step S500 , testing and updating the crystal until the preset accuracy is reached to obtain the specification parameters of the best crystal.

[0052] It is understandable that compensation accuracy is determined by a variety of factors. In actual operation, most batches of crystals cannot reach the preset accuracy or have a low pass rate after compensation. In this embodiment, by analyzing the crystal curve and adjusting the wafer specifications, the crystal (wafer size, wafer angle, wafer corrosion frequency, electrode area, etc.) is continuously updated, and the crystal oscillator is manufactured and compensated for testing until a crystal batch with a high pass rate of accuracy is obtained, so as to obtain specific wafer specification parameters.

[0053] When setting specifically, the preset accuracy is ±0.1ppm, that is, the solution in this embodiment adjusts the specifications with ±0.1ppm as the target accuracy, and finally obtains the specification parameters of the best crystal that can stably reach ±0.1ppm through the adjustment of the compensation system. The accuracy of the surface-mount temperature-compensated crystal oscillator is improved, and an effective and reliable preparation solution is provided for the preparation of high-precision surface-mount temperature-compensated crystal oscillators.

[0054] In a specific embodiment, the wafer etching coefficient is 0.8-1.3, and the etching frequency is 16204KHz. The specific restrictions on the etching parameters and the etching frequency can achieve high-precision control to meet the requirement of ±0.1ppm.

[0055] During the specific setting, the wafers used are 2520 and 3225 specifications, and the crystals are cut using the AT cutting method. After cutting, the wafer angle is 35°3′~35°16′. By limiting the specifications, the accuracy requirement of ±0.1ppm can be met.

[0056] In a specific example, the electrode area is 0.75×0.75 to 1.3×1. The limitation of the electrode area can satisfy the requirement of ±0.1ppm.

[0057] like Figure 2 , Figure 3 As shown, the second aspect of the present invention provides a structure of a surface-mounted temperature-compensated crystal oscillator, comprising: a base 10, a crystal 20, a first capacitor 40 and a second capacitor 50; an inner cavity 12 is formed in the base 10, a welding ring 11 is formed around the outer edge of the inner cavity 12, and a grounding pad 13 is formed inside the inner cavity 12; the crystal 20 is arranged in the grounding pad 13, and the crystal 20 is bonded to the grounding pad 13, and a chip 30 is mounted on the crystal 20; the first capacitor 40 and the second capacitor 50 are arranged at intervals, and one end of the first capacitor and the second capacitor are both connected to the grounding pad, the other end of the first capacitor is connected to the power supply, and the other end of the second capacitor is connected to the voltage control end (VC end) of the chip 30; wherein the specifications of the crystal 20 are prepared by the preparation method of the surface-mounted temperature-compensated crystal oscillator provided in any of the above embodiments.

[0058] Among them, one end of the first capacitor 40 and the second capacitor 50 is connected to the ground pad 13, the other end of the first capacitor 40 is connected to the power supply, and the other end of the second capacitor 50 is connected to the voltage control end of the chip 30. Specifically, both ends of the two capacitors are connected to the pad by bonding, and one of the capacitors is connected to the power supply, and the other capacitor is connected to the voltage control end of the chip. The ground terminal is two vertical rectangular small pads connected to the ground pad 13, one of the two small pads corresponding to the two capacitors is connected to the power supply, and the other is connected to the voltage control end of the chip 30. The coordination of the first capacitor 40 and the second capacitor 50 can improve the stability of the output frequency of the product, reduce the influence of the power supply to improve the product phase noise index, and better play the performance of the chip 30.

[0059] Specifically, the first capacitor 40 and the second capacitor 50 have different capacitance values, the first capacitor 40 is used to improve the stability of the output frequency of the product and reduce the influence of the power supply, and the second capacitor 50 is used to improve the phase noise index of the product.

[0060] Furthermore, a bottom pad 14 is provided on the crystal 20 , and the chip 30 is connected to the crystal 20 via the bottom pad 14 .

[0061] Specifically, the first capacitor 40 and the second capacitor 50 are bound to the ground pad by conductive glue, and the chip 30, capacitor and crystal 20 are simultaneously encapsulated inside the crystal oscillator, which can make the output frequency of the crystal oscillator more stable, reduce the deviation caused by other system equipment such as the power supply, reduce the overall height of the product, and put the product under inert gas protection, thereby improving reliability.

[0062] Specific processing, such as Figure 3As shown, a suitable pad is selected, the pad is the ground pad 13, the 3225 / 2520 crystal 20 and the capacitor are bonded to the ground pad of the base 10, and then the chip 30 is mounted on the crystal 20. The chip 30, the crystal 20 and the base 10 are bound to form an electrical connection, and then they are pressed and sealed to form a high-precision surface-mount temperature-compensated crystal oscillator.

[0063] The specification range of the crystal 20 can be determined by the above method. The specification of the crystal 20 is a wafer size of 2520 and 3225 wafers, a wafer angle of 35°3′~35°16′, and an electrode size range of approximately 0.75×0.75~1.3×1 mm.

[0064] For example, a chip specification that meets ±0.1ppm has a chip size of 2.1×1.348mm, an angle of 35°10′30″, an electrode area of ​​1.1×1mm, and a corrosion frequency of 16204KHz. By limiting the specification parameters, it can meet the requirement of ±0.1ppm. It should be understood that the above-mentioned parameter limitations are ideal parameters. In actual processing, due to errors and other reasons, the parameters can be solved by the limited parameter values.

[0065] It can be known from the above embodiments that the crystal oscillator assembly form of the present invention is to first mount the 3225 / 2520 crystal 20 and the capacitor on the bottom of the base 10, and then mount the chip 30 on the crystal 20, and the chip 30 is bound to the crystal 20 and the base 10 to form an electrical connection, and then the high-precision surface-mount temperature-compensated crystal oscillator is formed by compression sealing. The crystal oscillator can generate a square wave signal / cutting sine wave signal under a specified DC voltage. The optimal crystal 20 specifications are determined by wafer angle design, shape design, electrode design, corrosion frequency adjustment, etc.; according to the characteristics of the chip 30, the compensation system is matched, and the compensation process and algorithm optimization such as primary compensation + secondary compensation + performance verification are used to compensate the crystal 20 curve, so that the crystal oscillator accuracy reaches ±0.1ppm, breaking through the accuracy limitation in the relevant technology and improving the accuracy of the crystal oscillator.

[0066] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing a surface-mount temperature-compensated crystal oscillator, characterized in that: The following steps are involved: Obtaining specification parameter information and processing parameter information of the original wafer; Determine the electrode area, form the electrode on the wafer and package it to obtain the original crystal, test the original crystal and obtain the test result; Selecting the original crystals with different test results to respectively manufacture crystal oscillators, performing primary compensation, secondary compensation and verification on the prepared crystal oscillators, and obtaining the crystal oscillator temperature accuracy of the original crystals in different states; By matching the crystal oscillator temperature accuracy with the crystal temperature curve, the best crystal curve and a plan for improving the chip specification parameters are determined, and the specification parameter information of the original chip is updated according to the plan for improving the chip specification parameters to obtain an updated crystal; The updated crystal is tested until a preset accuracy is achieved to obtain the specification parameters of the best crystal.

2. The method for preparing a surface-mount temperature-compensated crystal oscillator according to claim 1, characterized in that: The specification parameter information includes wafer specifications, wafer angle and electrode area, and corrosion frequency.

3. The method for preparing a surface-mount temperature-compensated crystal oscillator according to claim 2, characterized in that: The wafer corrosion coefficient is 0.8-1.

3.

4. The method for preparing a surface-mount temperature-compensated crystal oscillator according to claim 2, characterized in that: The wafer angle is 35°3′~35°16′.

5. The method for preparing a surface-mount temperature-compensated crystal oscillator according to claim 1, characterized in that: The preset accuracy is ±0.1ppm.

6. The method for preparing a surface-mount temperature-compensated crystal oscillator according to claim 1, characterized in that: Electrodes are formed on a wafer and packaged to obtain an original crystal, and the original crystal is tested to obtain a test result, specifically comprising the following steps: Electrodes are formed on a wafer by sputtering and etching processes, and an original crystal is formed by SMD packaging. The original crystal is tested to obtain a frequency-temperature curve of the original crystal.

7. The method for preparing a surface-mount temperature-compensated crystal oscillator according to claim 6, characterized in that: The crystal, capacitor and chip are assembled together in a base, and then secondary packaging is performed to obtain the crystal oscillator.

8. The method for preparing a surface-mount temperature-compensated crystal oscillator according to claim 6, characterized in that: The crystal oscillator temperature accuracy is matched with the crystal temperature curve to determine the best crystal curve, including the following steps: By analyzing the frequency-temperature curve, the crystal oscillator accuracy of crystals with different specification parameters is made to correspond to it, and the one with the highest accuracy is taken as the best crystal curve.

9. The method for preparing a surface-mount temperature-compensated crystal oscillator according to claim 1, characterized in that: The electrode area is 0.75×0.75~1.3×1mm.

10. A surface mounted temperature compensated crystal oscillator, characterized in that: include: A base, wherein an inner cavity is formed in the base, a welding ring is formed around the outer edge of the inner cavity, and a grounding pad is formed inside the inner cavity; A crystal, the crystal is arranged in the ground pad, and the crystal is bonded to the ground pad, and a chip is mounted on the crystal; A first capacitor and a second capacitor, wherein the first capacitor and the second capacitor are arranged at an interval, and one end of the first capacitor and the second capacitor are both connected to the ground pad, the other end of the first capacitor is connected to a power supply, and the other end of the second capacitor is connected to a voltage control terminal of the chip; Wherein, the specifications of the crystal are prepared according to the preparation method of the surface-mount temperature-compensated crystal oscillator as described in any one of claims 1-9.

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