Preparation method of quartz crystal resonator and quartz crystal resonator

Abstract

This invention belongs to the field of resonator design technology, specifically disclosing a method for fabricating a quartz crystal resonator and the quartz crystal resonator itself. The method includes step S1: AT cutting a quartz wafer to form a substrate of a predetermined shape; step S2: calculating the required etching thickness of the substrate based on the desired operating frequency of the quartz crystal resonator; step S3: symmetrically setting desired etching regions at the center positions of the upper and lower surfaces of the substrate, and etching the etching regions using an etching process, wherein the etched thickness is the thickness calculated in step S2; step S4: using a coating process, depositing an oscillating electrode onto the etched regions, such that the oscillating electrode forms a predetermined gap with the outer edge of the etched regions, thereby fabricating the quartz crystal resonator. This invention can solve the problem of fabricating quartz crystal resonators with fundamental frequencies above 200MHz.

Description

Technical Field

[0001] This invention belongs to the field of resonator design technology, specifically relating to a method for preparing a quartz crystal resonator and the quartz crystal resonator itself. Background Technology

[0002] The thickness of a quartz crystal resonator wafer is inversely proportional to its frequency. A 200MHz high-frequency wafer has a working region thickness of only 8μm, making it difficult to process effectively with current technologies. Traditional grinding processes can only achieve a wafer thickness of around 30μm, resulting in a frequency of approximately 55MHz. Higher frequencies become too thin for further processing. Chemical etching, even with overall wafer thinning, only achieves a frequency of around 80MHz, with a wafer thickness of approximately 20μm. Higher frequencies would result in wafers too thin to meet mechanical strength requirements. Summary of the Invention

[0003] The purpose of this invention is to provide a method for fabricating a quartz crystal resonator and a quartz crystal resonator. This method for fabricating a high-frequency quartz crystal resonator and the quartz crystal resonator are applicable to SMD-type high-frequency quartz crystal resonators and can solve the problem of fabricating quartz crystal wafers with high frequencies above 200MHz.

[0004] To achieve the above objectives, according to one aspect of this application, a method for fabricating a quartz crystal resonator is provided, the method comprising:

[0005] Step S1: Perform AT cutting on the quartz wafer to form a substrate of a predetermined shape;

[0006] Step S2: Calculate the required etching thickness of the substrate based on the desired operating frequency of the quartz crystal resonator;

[0007] Step S3: Symmetrically set the desired etching areas at the center positions of the upper and lower surfaces of the substrate, and use an etching process to etch the etching areas, wherein the thickness of the etched areas is the thickness calculated in step S2.

[0008] Step S4: Using a coating process, an oscillating electrode is deposited on the corroded area, and a predetermined gap is formed between the oscillating electrode and the outer edge of the corroded area to prepare the quartz crystal resonator.

[0009] Furthermore, the substrate is a cuboid substrate, and the etched area is a circular etched area.

[0010] Furthermore, the diameter of the etched region is 0.6 to 0.7 times the length of the short side of the substrate.

[0011] Furthermore, in step S4, the oscillation electrode is a gold electrode or a silver electrode.

[0012] Furthermore, the method for fabricating the quartz crystal resonator further includes: depositing a first conductive electrode connected to the oscillation electrode on the upper surface, the first conductive electrode extending along the length direction of the substrate and passing through the side of the substrate to the lower surface of the substrate.

[0013] Furthermore, the method for fabricating the quartz crystal resonator further includes: depositing a second conductive electrode on the lower surface that is connected to the oscillation electrode on the lower surface, the second conductive electrode extending along the length direction of the substrate and passing through the side of the substrate to the upper surface of the substrate.

[0014] Furthermore, the oscillating electrode region is larger than one-quarter of the corrosion region and smaller than three-quarters of the corrosion region.

[0015] Further, in step S2, the thickness is calculated using the formula f = Kf / d, where f is the oscillation frequency of the quartz crystal resonator; Kf is a frequency constant of 1670 kHz / mm; and d is the required thickness of the substrate to be etched, in mm.

[0016] On the other hand, this application also provides a quartz crystal resonator, which is prepared by the above-described preparation method, and the quartz crystal resonator includes:

[0017] The substrate is a quartz wafer, and grooves are symmetrically provided on the upper and lower surfaces of the substrate;

[0018] An oscillating electrode is disposed at the center of the groove and forms a predetermined gap with the outer edge of the corrosion area.

[0019] Furthermore, a first conductive electrode connected to the oscillation electrode on the upper surface is deposited thereon, the first conductive electrode extending along the length direction of the substrate and passing through the side of the substrate to the lower surface of the substrate; a second conductive electrode connected to the oscillation electrode on the lower surface is deposited thereon, the second conductive electrode extending along the length direction of the substrate and passing through the side of the substrate to the upper surface of the substrate.

[0020] The technical solution of this invention can be used to prepare a quartz crystal resonator through the following steps: Step S1: AT cutting a quartz wafer to form a substrate of a predetermined shape; Step S2: Calculating the required etching thickness of the substrate according to the desired operating frequency of the quartz crystal resonator; Step S3: Symmetrically setting the required etching regions at the center positions of the upper and lower surfaces of the substrate, and etching the etching regions using an etching process, wherein the etched thickness of the etching regions is the thickness calculated in step S2; Step S4: Using a coating process, depositing an oscillating electrode on the etched regions, and forming a predetermined gap between the oscillating electrode and the outer edge of the etched regions to prepare the quartz crystal resonator.

[0021] In other words, this preparation method can use an etching process to directly perform local etching on the center of a small-sized quartz wafer to form an etched area, so that the thickness of the center of the quartz wafer reaches less than 10μm. Then, a gold electrode is deposited on the center of the etched area of ​​the quartz wafer through a coating process, which can obtain a high-frequency quartz resonator with a fundamental frequency of up to 200MHz or more, meeting the requirements of miniaturization and high frequency of quartz crystal resonators. Attached Figure Description

[0022] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0023] Figure 1 This is a flowchart of the method for fabricating a quartz crystal resonator disclosed in the embodiments of this application;

[0024] Figure 2 This is a schematic diagram of the structure of the quartz crystal resonator disclosed in the embodiments of this application;

[0025] Figure 3 yes Figure 2 Top view of the upper surface;

[0026] Figure 4 yes Figure 2 Top view of the lower surface of the middle surface;

[0027] Figure 5 yes Figure 2 Top view of the side along the middle length direction;

[0028] Figure 6 yes Figure 2 Top view of the side in the middle width direction.

[0029] Explanation of reference numerals in the attached figures:

[0030] 10. Substrate; 11. Etched area; 12. Oscillating electrode; 100. Predetermined gap; 13. Upper surface; 14. Lower surface; 15. Groove; 20. First conductive electrode; 30. Second conductive electrode. Detailed Implementation

[0031] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. The advantages and features of the present invention will become clearer from the following description and claims. It should be noted that the drawings are all in a very simplified form and are not to a precise scale, and are only used to facilitate and clarify the illustration of the embodiments of the present invention.

[0032] It should be noted that, in order to clearly illustrate the content of this invention, several embodiments are provided to further explain different implementations of the invention. These embodiments are enumerated rather than exhaustive. Furthermore, for the sake of brevity, content mentioned in the preceding embodiments is often omitted in the following embodiments. Therefore, content not mentioned in the later embodiments can be referred to in the preceding embodiments.

[0033] See Figures 1 to 6 As shown, according to an embodiment of this application, a method for fabricating a quartz crystal resonator is provided. This method is applicable to SMD-type high-frequency quartz crystal resonators. The method for fabricating the quartz crystal resonator includes:

[0034] Step S1: Perform AT cutting on the quartz wafer to form a substrate 10 of a predetermined shape.

[0035] In this step, the quartz wafer can be AT-cut to cut the quartz wafer into a substrate of a predetermined shape, such as a cuboid substrate, a cube substrate, or other irregularly shaped substrate.

[0036] Furthermore, AT cutting is the most widely used cutting method, with different angles (basically 35°), and is particularly suitable for electronic instruments requiring oscillators to operate in the 500kHz to 300MHz range. One of the advantages of this quartz cutting is its temperature coefficient. This value becomes zero at 26°C, and even on either side, it is relatively flat, especially compared to other cuts. AT cutting is thickness-dependent; the frequency of the resulting quartz wafer depends only on the thickness, meaning that controlling the thickness controls the frequency.

[0037] Step S2: Calculate the required etching thickness of substrate 10 based on the operating frequency of the required quartz crystal resonator.

[0038] As can be seen from the description of step S1: In this embodiment, AT cutting is used, and the frequency of the cut quartz wafer is only related to the thickness. That is to say, controlling the thickness controls the frequency. In other words, the thickness of the substrate 10 can be calculated according to the required frequency, so that the next step can be carried out.

[0039] Furthermore, in this step, the thickness of the substrate 10 is calculated using the formula f = Kf / d, where f is the oscillation frequency of the quartz crystal resonator; Kf is the frequency constant, which is 1670 kHz / mm; and d is the required etching thickness of the substrate 10, in mm. The thickness corresponding to each frequency can be calculated using this formula.

[0040] Step S3: Symmetrically set the required etching regions 11 at the center positions of the upper and lower surfaces of the substrate 10, and use the etching process to etch the etching regions 11, and the thickness of the etched regions 11 is the thickness calculated in step S2.

[0041] Combination Figure 2 , Figure 3 and Figure 4 As shown, the required etching regions 11 are symmetrically arranged at the center positions of the upper surface 13 and the lower surface 14 of the substrate 10. This arrangement makes it easier for the quartz crystal resonator to start oscillating and achieve better oscillation performance during actual operation. At this point, the thickness corresponding to the required frequency can be calculated according to the formula in step S2, and the etching process can be used to etch the etching regions 11.

[0042] Specifically, in this embodiment, the substrate 10 is a cuboid substrate, and the etched region 11 is a circular etched region. This configuration facilitates processing. Of course, the etched region 11 can also be a square or rectangular etched region; this application does not impose any specific limitations.

[0043] Furthermore, the diameter of the etched region 11 is 0.6 to 0.7 times the length of the short side of the substrate 10, for example, 0.6, 0.65, or 0.7 times. In this embodiment, the short side is the width of the cuboid substrate. When the diameter of the etched region 11 is less than 0.6 times the length of the short side of the substrate 10, the etched region 11 is too small, making processing inconvenient. When the diameter of the etched region 11 is greater than 0.7 times the length of the short side of the substrate 10, the substrate 10 may not be able to support the substrate during actual processing, leading to substrate breakage, wasting materials, and increasing costs. Therefore, when the diameter of the etched region 11 is 0.6 to 0.7 times the length of the short side of the substrate 10, it is convenient to process and will not cause the substrate 10 to break during processing, greatly saving costs.

[0044] Step S4: Using a coating process, an oscillating electrode 12 is deposited on the etched region 11, and a predetermined gap 100 is formed between the oscillating electrode 12 and the outer edge of the etched region 11 to prepare a quartz crystal resonator.

[0045] In this step, after the etched area 11 is coated with the oscillation electrode 12 using a coating process, the quartz crystal resonator can oscillate during actual operation. Optionally, the oscillation electrode 12 is a gold electrode or a silver electrode, as gold or silver electrodes have good conductivity and high chemical stability. Because quartz crystal wafers have very poor conductivity, coating with the oscillation electrode 12 can increase their conductivity.

[0046] Furthermore, the area of ​​the oscillating electrode 12 is larger than one-quarter and smaller than three-quarters of the corrosion area 11, for example, two-quarters, two-and-a-half, or two-and-a-half. When the area of ​​the oscillating electrode 12 is less than or equal to one-quarter of the corrosion area 11, the quartz crystal resonator is not easy to start oscillating during actual operation, and the oscillation effect is poor. When the area of ​​the oscillating electrode 12 is greater than or equal to three-quarters of the corrosion area 11, parasitic frequencies will be generated, thus affecting the oscillation effect of the quartz crystal resonator. Therefore, when the area of ​​the oscillating electrode 12 is larger than one-quarter and smaller than three-quarters of the corrosion area 11, the quartz crystal resonator is easy to start oscillating and has a good oscillation effect during actual operation; and no parasitic frequencies will be generated, thus not affecting the oscillation effect of the quartz crystal resonator.

[0047] After completing step S4, a first conductive electrode 20 connected to the oscillation electrode 12 of the upper surface 13 is deposited on the upper surface 13. The first conductive electrode 20 extends along the length direction of the substrate 10 and passes through the side of the substrate 10 to the lower surface 14 of the substrate 10. A second conductive electrode 30 connected to the oscillation electrode 12 of the lower surface 14 is deposited on the lower surface 14. The second conductive electrode 30 extends along the length direction of the substrate 10 and passes through the side of the substrate 10 to the upper surface 13 of the substrate 10.

[0048] When the first conductive electrode 20 extends along the length of the substrate 10 and passes through the side of the substrate 10 to the lower surface 14 of the substrate 10, the upper surface 13 and the lower surface 14 of the upper end of the substrate 10 can be connected to the oscillation electrode 12 of the upper surface 13. When the second conductive electrode 30 extends along the length of the substrate 10 and passes through the side of the substrate 10 to the upper surface 13 of the substrate 10, the upper surface 13 and the lower surface 14 of the lower end of the substrate 10 can be connected to the oscillation electrode 12 of the lower surface 14.

[0049] Optionally, the first conductive electrode 20 and the second conductive electrode 30 are symmetrically disposed on the substrate 10 (in combination with...). Figure 3 and Figure 4(As shown). With the symmetrically arranged first conductive electrode 20 and second conductive electrode 30, the quartz crystal resonator exhibits good oscillation performance during actual operation. The first conductive electrode 20 and the second conductive electrode 30 can be made of gold or silver.

[0050] It should be noted that the upper and lower ends mentioned here are determined relative to the positions of the first conductive electrode 20 and the second conductive electrode 30. In actual use, the positions are set according to the usage conditions, and this application does not make specific limitations.

[0051] The above preparation process is illustrated by taking the etching region 11 of a 22MHz SMD quartz wafer etched to 200MHz±5000kHz as an example:

[0052] The 22MHz SMD baseband quartz wafer was AT-cut at an angle of 35°22′±15″; the SMD baseband quartz wafer had the following dimensions: length: 5.00mm + (0.00mm~0.05mm); width: 2.50mm + (0.00mm~0.0mm); thickness: 0.076mm.

[0053] The required corrosion zone thickness for 200MHz was calculated using the formula f = Kf / d, and the calculated thickness of the corrosion zone was 0.008mm.

[0054] Etched regions 11 are symmetrically set at the center of the upper surface 13 and lower surface 14 of the SMD baseband quartz wafer, and the thickness of the etched regions 11 is etched to 0.008mm through an etching process. The thickness of the etched regions 11 of the SMD baseband quartz wafer can reach less than 10μm; the diameter of the etched regions 11 is 1.80mm + (0.10mm ~ 0.10mm).

[0055] A gold or silver electrode is deposited on the etched area 11 using a coating process, forming a predetermined gap 100 between the gold or silver electrode and the outer edge of the etched area 11. The diameter of the gold or silver electrode is 1 mm.

[0056] A first conductive electrode 20, connected to the oscillation electrode 12 on the upper surface 13, is deposited using a coating process. The first conductive electrode 20 extends along the length of the substrate 10 and passes through the side of the SMD quartz wafer to the lower surface 14 of the substrate 10. A second conductive electrode 30, connected to the oscillation electrode 12 on the lower surface 14, is deposited on the lower surface 14. The second conductive electrode 30 extends along the length of the SMD quartz wafer and passes through the side of the substrate 10 to the upper surface 13 of the SMD quartz wafer.

[0057] After plating gold or silver electrodes, the first conductive electrode 20, and the second conductive electrode 30, the fundamental frequency of the quartz resonator can reach over 200MHz.

[0058] As can be seen from the above description, by using the preparation method in this application, a circular etched area is formed by directly etching the center of a small quartz wafer using an etching process, so that the thickness of the center of the quartz wafer reaches less than 10μm. Then, a gold electrode is deposited on the center of the etched area of ​​the SMD wafer using a coating process, and a high fundamental frequency quartz resonator with a fundamental frequency of up to 200MHz can be obtained, which meets the requirements of miniaturization and high frequency of quartz resonators.

[0059] Combination Figures 1 to 6 As shown, an embodiment of this application also provides a quartz crystal resonator, which is prepared using the above-described method for preparing a quartz crystal resonator. The quartz crystal resonator includes a substrate 10 and an oscillation electrode 12. The substrate 10 is a quartz wafer, and grooves 15 are symmetrically arranged at the center of the upper surface 13 and the lower surface 14 of the substrate 10. The oscillation electrode 12 is disposed at the center of the groove and forms a predetermined gap 100 with the outer edge of the etched region 11.

[0060] The quartz crystal resonator fabricated using the same method as a quartz crystal resonator has symmetrically arranged grooves 15 at the center of the upper and lower surfaces of the substrate 10. This arrangement eliminates the need for the grooves 15 to completely cover the entire substrate 10. The thickness of the grooves 15 can be calculated based on the operating frequency of the quartz crystal resonator, and can be obtained by etching the grooves 15 using an etching process. The final etched thickness corresponds to the desired operating frequency. Furthermore, the oscillation electrode 12 is positioned at the center of the grooves 15, forming a predetermined gap 100 with the outer edge of the etched area 11. By setting this predetermined gap 100, the quartz crystal resonator is easier to start oscillating and exhibits better oscillation performance during actual operation; it also prevents the generation of parasitic frequencies that could affect the oscillation effect of the quartz crystal resonator.

[0061] Specifically, a first conductive electrode 20 connected to the oscillation electrode 12 of the upper surface 13 is plated on the upper surface 13. The first conductive electrode 20 extends along the length of the substrate 10 and passes through the side of the substrate 10 to the lower surface 14 of the substrate 10. Both electrodes at the upper end of the substrate 10 can be connected to the oscillation electrode 12 of the upper surface 13.

[0062] A second conductive electrode 30 is plated on the lower surface 14 and connected to the oscillation electrode 12 of the lower surface 14. The second conductive electrode 30 extends along the length direction of the substrate 10 and passes through the side of the substrate 10 to the upper surface 13 of the substrate 10, so that both electrodes at the lower end of the substrate 10 can be connected to the oscillation electrode 12 of the lower surface 14.

[0063] Optionally, the quartz crystal resonator can be bonded to a surface-mount ceramic base with conductive adhesive, and an external crystal lead can be connected. The metal cover and the ceramic base are sealed together to form the external package of the product, thus forming a surface-mount SMD high-frequency quartz crystal resonator.

[0064] For ease of description, spatial relative terms such as "above," "on top of," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation beyond the orientation of the device as described in the figures. For example, if the device in the figures were inverted, a device described as "above" or "on top of" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein will be interpreted accordingly.

[0065] Furthermore, it should be noted that the use of terms such as "first" and "second" to define components is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore cannot be construed as limiting the scope of protection of this application.

[0066] The above are merely preferred embodiments of this application and are not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A method for fabricating a quartz crystal resonator, characterized in that, include: Step S1: Perform AT cutting on the quartz wafer to form a substrate (10) of a predetermined shape; Step S2: Calculate the required etching thickness of the substrate (10) based on the desired operating frequency of the quartz crystal resonator; Step S3: Symmetrically set the desired etching region (11) at the center position of the upper surface (13) and lower surface (14) of the substrate (10), and use the etching process to etch the etching region (11), and the thickness of the etching region (11) is the thickness calculated in step S2. Step S4: Using a coating process, an oscillating electrode (12) is coated on the corrosion area (11), and a predetermined gap (100) is formed between the oscillating electrode (12) and the outer edge of the corrosion area (11) to prepare the quartz crystal resonator. The substrate (10) is a cuboid substrate, and the etched area (11) is a circular etched area; The method for preparing the quartz crystal resonator further includes: depositing a first conductive electrode (20) connected to the oscillation electrode (12) on the upper surface (13), wherein the first conductive electrode (20) extends along the length direction of the substrate (10) and passes through the side of the substrate (10) to the lower surface (14) of the substrate (10).

2. The method for fabricating a quartz crystal resonator as described in claim 1, characterized in that, The diameter of the etched region (11) is 0.6 to 0.7 times the length of the short side of the substrate (10).

3. The method for fabricating a quartz crystal resonator as described in claim 1, characterized in that, In step S4, the oscillation electrode (12) is a gold electrode or a silver electrode.

4. The method for fabricating a quartz crystal resonator as described in claim 1, characterized in that, The method for preparing the quartz crystal resonator further includes: depositing a second conductive electrode (30) connected to the oscillation electrode (12) of the lower surface (14) on the lower surface (14), the second conductive electrode (30) extending along the length direction of the substrate (10) and passing through the side of the substrate (10) to the upper surface (13) of the substrate (10).

5. The method for fabricating a quartz crystal resonator as described in claim 1, characterized in that, The region of the oscillating electrode (12) is larger than one-quarter and smaller than three-quarters of the corrosion region (11).

6. The method for fabricating a quartz crystal resonator as described in claim 1, characterized in that, In step S2, the thickness is calculated using the formula f = Kf / d, where f is the oscillation frequency of the quartz crystal resonator; Kf is a frequency constant of 1670 kHz / mm; and d is the required thickness of the substrate (10) to be etched, in mm.

7. A quartz crystal resonator, wherein the quartz crystal resonator is prepared by the preparation method according to any one of claims 1 to 6, characterized in that, The quartz crystal resonator includes: The substrate (10) is a quartz wafer, and grooves (15) are symmetrically provided on the upper surface (13) and lower surface (14) of the substrate (10). An oscillating electrode (12) is laid in the center of the groove (15) and forms a predetermined gap (100) with the outer edge of the corrosion area (11).

8. The quartz crystal resonator as described in claim 7, characterized in that, A first conductive electrode (20) connected to the oscillation electrode (12) of the upper surface (13) is plated on the upper surface (13). The first conductive electrode (20) extends along the length direction of the substrate (10) and passes through the side of the substrate (10) to the lower surface (14) of the substrate (10). A second conductive electrode (30) connected to the oscillation electrode (12) of the lower surface (14) is plated on the lower surface (14). The second conductive electrode (30) extends along the length direction of the substrate (10) and passes through the side of the substrate (10) to the upper surface (13) of the substrate (10).

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