High fundamental frequency MESA wafer

Abstract

The utility model relates to the technical field of MESA wafers, in particular to a high-fundamental-frequency MESA wafer which comprises a wafer body, the periphery of the wafer body is rectangular, the wafer body comprises a vibration part and a fixing part, the vibration part is formed by etching and recessing the two side faces, the fixing part and the vibration part are integrally arranged, the distance between the vibration part and the free end of the fixing part is defined as L1, and the distance between the vibration part and the free end of the fixing part is defined as L2. The distance between the vibrating part and the dispensing end of the fixed part is L2, and L1 / L2 is greater than 1 and less than or equal to 1.3; and each electrode comprises excitation electrodes arranged on the two opposite side faces of the vibration part respectively and extraction electrodes connected with the excitation electrodes and extracted to the dispensing end of the fixing part. According to the invention, on the basis of not increasing the preparation difficulty, the resistance of the high-fundamental-frequency quartz wafer of 250MHz and above is effectively reduced, so that the performance parameters of the wafer are improved.

Description

Technical Field

[0001] The present application relates to the field of chip technology, and in particular to a high fundamental frequency MESA chip. Background Art

[0002] With the rapid development of electronic information technology, quartz crystal devices are facing demands for high frequency and high performance parameters. In traditional quartz component manufacturing, high-base-frequency (≥250MHz) quartz wafers have failed to be produced due to processing limitations. To address this problem, researchers have developed a method for locally treating the quartz surface during oscillator production using a stable etching method to obtain high-base-frequency MESA wafers.

[0003] The main evaluation parameter for quartz crystal devices is resistance, where lower resistance increases the vibration frequency. Related documents disclose a high-base-frequency quartz crystal wafer comprising a vibrating region for vibrating the wafer and a fixed region for connecting the vibrating region to a base. By separating the vibrating and fixed regions of the wafer, resistance is reduced.

[0004] Regarding the above-mentioned related technologies, for high fundamental frequency quartz wafers of 250 MHz and above, there is a problem that the separation etching precision is difficult to control, resulting in difficulty in reducing resistance. Utility Model Content

[0005] In order to effectively reduce the resistance of high fundamental frequency quartz chips of 250MHz and above without increasing the difficulty, so as to improve the performance parameters of the chips, the purpose of this application is to provide a high fundamental frequency MESA chip.

[0006] A high fundamental frequency MESA chip, comprising:

[0007] The sheet body has a rectangular outer periphery, and includes a vibrating portion formed by etching depressions on both sides, and a fixed portion integrally provided with the vibrating portion, wherein the distance between the vibrating portion and the free end of the fixed portion is defined as L1, and the distance between the vibrating portion and the dispensing end of the fixed portion is defined as L2, and 1<L1 / L2≤1.3;

[0008] A pair of electrodes, each electrode includes an excitation electrode disposed on two opposite sides of the vibration part, and an extraction electrode connected to the excitation electrode and led to the dispensing end of the fixing part.

[0009] Optional, 1.2≤L1 / L2≤1.3.

[0010] Optionally, the shape of the vibration part is one of circular, elliptical, and stadium-shaped.

[0011] Optionally, the excitation electrode is circular and is coaxially arranged with the vibration part.

[0012] Optionally, the lead-out electrode includes a fan-shaped portion connected to the excitation electrode, and a dispensing portion connected to the fan-shaped portion and arranged at the dispensing end of the fixed portion, wherein the dispensing portion includes a pair of surface layers laid on both sides of the sheet body, and a pair of end surface layers used to connect the surface layers and laid on the end sides of the sheet body.

[0013] Optionally, the aspect ratio of the sheet is 1.5-1.7:1.

[0014] Optionally, the aspect ratio of the sheet is 1.6:1.

[0015] Optionally, the thickness of the vibration part is 3.3-4.7 μm.

[0016] In summary, this application includes at least one of the following beneficial technical effects:

[0017] 1. For high fundamental frequency quartz crystals of 250MHz and above, the vibration part moves downward, effectively reducing the chip body resistance by 18.47%, effectively improving the performance parameters of the chip;

[0018] 2. The vibration part is provided with an arc-shaped area, for example, the vibration part is provided with a circular, elliptical, or stadium-shaped area, which further reduces the chip resistance by 30.24%. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 Schematic diagram of the structure of the high fundamental frequency MESA chip described in Example 1 of the present application;

[0020] Figure 2 Schematic diagram of the structure of the high fundamental frequency MESA chip described in Example 3 of the present application;

[0021] Figure 3 Schematic diagram of the structure of the high fundamental frequency MESA chip described in Example 4 of the present application;

[0022] Figure 4 Schematic diagram of the structure of the high fundamental frequency MESA chip described in Example 5 of the present application;

[0023] Figure 5 This is a structural diagram of the high fundamental frequency MESA chip described in one of the technical solutions of this application.

[0024] Figure 6 This is a resistance value test distribution diagram of the wafer described in Comparative Example 1 and Example 3 of the present application, wherein: Figure 6 (a) For proportion 1, Figure 6 (b) corresponds to Example 3.

[0025] Explanation of the accompanying symbols: 1. Sheet; 2. Vibrating part; 3. Fixing part; 4. Electrode; 5. Excitation electrode; 6. Lead-out electrode; 7. Fan-shaped part; 8. Glue dispensing part. DETAILED DESCRIPTION

[0026] The following is combined with Figure 1 -Attached Figure 6 , further details of this application are given.

[0027] It should be understood that terms such as “having”, “including” and “comprising” used herein do not preclude the existence or addition of one or more other elements or combinations thereof.

[0028] The utility model provides a high fundamental frequency MESA chip, comprising a chip body 1 and a pair of electrodes 4:

[0029] The outer periphery of the sheet 1 is rectangular. In this technical solution, the sheet 1 is a rectangle with a certain thickness, and its thickness is set according to specific needs. In one technical solution, the thickness of the sheet 1 is set to 65-75 μm. Exemplarily, the thickness of the sheet 1 is 70 μm.

[0030] The sheet 1 includes a vibration part 2 formed by etching depressions on both sides. In this technical solution, the vibration part 2 formed by etching depressions on both sides of the sheet 1, that is, the area formed after etching is relatively thin compared to the sheet 1, and the shape of the vibration part 2 can be rectangular (refer to Figure 1 ), stadium shape (refer to Figure 2 ), oval (refer to Figure 3 ), circle (refer to Figure 4 ), Alien (Refer to Figure 5 The exemplary irregular shape may be a figure formed by connecting an arc and a rectangle, etc. The shape is not specifically limited in this technical solution. The vibrating portion 2 is disposed on the corresponding wafer along the width direction. For example, along the width direction, the distances between the two end surfaces of the wafer 1 and the edge of the vibrating portion 2 are equal.

[0031] In another specific technical solution, the shape of the vibrating portion 2 can preferably include an arcuate region, that is, it can be circular, elliptical, or spherical. In this technical solution, the spherical shape is a rectangle with slightly curved ends at both ends. With this technical solution, compared to a rectangle, if the vibrating portion 2 has the same area, the circular, elliptical, or spherical shape has lower resistance, that is, better performance parameters.

[0032] The sheet 1 also includes a fixing portion 3 integrally formed with the vibrating portion 2. In this technical solution, the fixing portion 3 is the portion remaining after the vibrating portion 2 is etched from the sheet 1. The fixing portion 3 and the vibrating portion 2 are integrally formed, and the thickness of the fixing portion 3 is equal to the original thickness of the sheet 1. The fixing portion 3 extends along the length of the sheet 1, with the end used for dispensing being the dispensing end and the end opposite the dispensing end being the free end.

[0033] Define the distance between the vibrating portion 2 and the free end of the fixing portion 3 as L1, and the distance between the vibrating portion 2 and the adhesive dispensing end of the fixing portion 3 as L2, where 1 < L1 / L2 ≤ 1.3. In this technical solution, L1 is the distance between the center of the vibrating portion 2 and the free end of the fixing portion 3, and L2 is the distance between the center of the vibrating portion 2 and the adhesive dispensing end of the fixing portion 3. 1 < L1 / L2 indicates that the vibrating portion 2 is positioned closer to the adhesive dispensing end. L1 / L2 ≤ 1.3 limits the proximity to the adhesive dispensing end, ensuring the resistance reduction effect while avoiding excessive compression of the adhesive dispensing end, which may affect the adhesive dispensing and fixing effect.

[0034] In another technical solution, 1.2≤L1 / L2≤1.3. In this technical solution, L1 / L2 can be any ratio within this range, such as 1.2, 1.25, or 1.3. On the basis of ensuring the dispensing fixation effect, the resistance is further reduced and the performance parameters of the chip are improved.

[0035] A pair of electrodes 4, which can be a metal layer, specifically an Au+Cr layer. Each electrode 4 includes an excitation electrode 5 and an extraction electrode 6. The pair of excitation electrodes 5 are disposed on opposite sides of the vibrating portion 2. The extraction electrodes 6 are connected to the excitation electrodes 5 and extend to the glue dispensing end of the fixed portion 3. The pair of extraction electrodes 6 are spaced apart along the width of the sheet 1.

[0036] In this technical solution, the chip 1 is packaged to form a resonator. The lead electrodes 6 of the chip 1 are connected to the resonator's pads via glue dispensing. These pads are then connected to a specific circuit. The excitation electrodes 5 on either side of the vibrating portion 2 generate a voltage, causing the chip to vibrate under the piezoelectric effect, outputting a specific frequency and realizing the resonator function. This technical solution effectively reduces the resistance of the chip 1 and improves the chip's performance for high-base-frequency quartz chips of 250MHz and above by moving the vibrating portion 2 downward and limiting the ratio 1 to less than L1 / L2.

[0037] The shape of the excitation electrodes 5 can be a cross-shaped square (see Figure 5), circular, or elliptical. To further enhance the resistance reduction effect, in another technical solution, the excitation electrode 5 is circular and coaxially arranged with the vibrating portion 2. With this solution, the circular excitation electrode 5 can further improve wafer performance, enabling the lens to have low resistance, thereby increasing the Q value and optimizing the SPDB value and parasitic resistance (SPUR).

[0038] In another technical solution, the lead-out electrode 6 includes a fan-shaped portion 7 connected to the excitation electrode 5, and a glue-dispensing portion 8 connected to the fan-shaped portion 7 and disposed at the glue-dispensing end of the fixed portion 3. The glue-dispensing portion 8 includes a pair of surface layers applied to the two side surfaces of the sheet 1, and a pair of end surface layers applied to the end sides of the sheet 1 for connecting the surface layers. In this technical solution, the fan-shaped portion 7 is provided on both side surfaces of the sheet 1 and then led out through the glue-dispensing portion 8. With this solution, the glue-dispensing portion 8 includes a surface layer and a cross-section layer, which increases the glue-dispensing contact area, ensures glue-dispensing stability, and improves the electrical connection between the lead-out electrode 6 and the external pad. The provision of the fan-shaped portion 7 further improves the stability of electrical transmission of the entire device.

[0039] In another technical solution, the aspect ratio of the chip 1 is 1.5-1.7:1. In this technical solution, the width of the chip 1 is defined as 1, and the length is 1.5-1.7 times the width. For example, the aspect ratio of the chip 1 can be 1.5:1, 1.6:1, or 1.7:1; preferably, the aspect ratio of the chip 1 is 1.6:1. This solution effectively coordinates the configuration of the vibration unit 2 by controlling the aspect ratio of the chip 1, further reducing resistance and increasing the Q value, thereby improving chip performance.

[0040] In another technical solution, the thickness of the vibration part 2 is 3.3-4.7 μm. For example, the thickness of the vibration part 2 is 3.3 μm, 4.0 μm, or 4.7 μm. This solution, by limiting the thickness of the vibration part 2, can effectively coordinate the configuration of the vibration part 2, achieving a high fundamental frequency while reducing resistance and increasing the Q value, thereby improving chip performance.

[0041] Example 1:

[0042] A high fundamental frequency MESA chip, the chip package size can be 2016 type, 2520 type, 3225 type ceramic base, refer to Figure 1 Taking the 3225 ceramic base package as an example, the fundamental frequency is 285Mhz, the chip aspect ratio is set to 1.6:1, the vibration zone area is set to about 1 / 2 of the chip area, and the effective electrode facing area is about 0.212mm 2, wherein the distance between the vibrating part and the free end of the fixed part is defined as L1, the distance between the vibrating part and the dispensing end of the fixed part is defined as L2, and L1 / L2=1.3;

[0043] The thickness of the sheet body is 70 μm, and the thickness of the vibration part is 4 μm.

[0044] Example 2

[0045] A high fundamental frequency MESA chip, the high fundamental frequency MESA chip is the same as embodiment 1, except that: the distance between the vibrating part and the free end of the fixed part is defined as L1, the distance between the vibrating part and the dispensing end of the fixed part is defined as L2, L1 / L2=1.2.

[0046] Example 3

[0047] A high fundamental frequency MESA chip, referring to Figure 2 The high fundamental frequency MESA chip is the same as that in Example 1, and the vibration part is in the shape of a stadium.

[0048] Example 4

[0049] A high fundamental frequency MESA chip, referring to Figure 3 The high fundamental frequency MESA chip is the same as that in Example 1, and the vibration portion is elliptical.

[0050] Example 5

[0051] A high fundamental frequency MESA chip, referring to Figure 4 The high fundamental frequency MESA chip is the same as that in Example 1, and the vibration part is circular.

[0052] Comparative Example 1

[0053] A high fundamental frequency MESA chip, the high fundamental frequency MESA chip is the same as Example 1, except that: the distance between the vibrating part and the free end of the fixed part is defined as L1, the distance between the vibrating part and the dispensing end of the fixed part is defined as L2, L1 / L2=1:1.3.

[0054] Comparative Example 2

[0055] A high fundamental frequency MESA chip, the high fundamental frequency MESA chip is the same as Example 1, except that: the distance between the vibrating part and the free end of the fixed part is defined as L1, the distance between the vibrating part and the dispensing end of the fixed part is defined as L2, L1 / L2=1:1.

[0056] test

[0057] 1. Take a number of products obtained in Example 1-2 and Comparative Example 1-2 (each containing more than 30 pieces), and perform vibration parameter testing after packaging. The vibration parameters include resistance and quality factor Q. The test results are shown in Table 1; Example 1.

[0058] Table 1

[0059]

[0060]

[0061] According to Table 1, the average resistance values of Examples 1 and 2 are lower than those of Comparative Examples 1 and 2. The average resistance value of Example 1 is reduced by 18.47% relative to that of Comparative Example 1, and the quality factor of Example 1 is increased by 14.97% relative to that of Comparative Example 1, which significantly improves the performance parameters of the chip. The reduction in resistance and the improvement in quality factor indicate that the frequency stability of the chip is significantly improved.

[0062] 2. Take a number of products obtained in Example 1 and Examples 3-5 (each containing more than 30 pieces), package them and perform vibration parameter testing. The vibration parameters include resistance. The test results are shown in Table 2.

[0063] Table 2

[0064] Example 1 Example 3 Example 4 Example 5 Resistance (Ω) 13.06 11.30 11.99 11.70 Variance 3S 1.26 1.72 1.14 1.59

[0065] Table 2 shows that, compared to Example 1, the resistance values of Examples 3, 4, and 5 were further reduced by 8.19-13.47%. This indicates that, compared to a rectangular shape, a circular or near-circular shape (e.g., an elliptical or stadium-shaped shape) exhibits lower resistance, resulting in superior performance parameters, given the same vibrating area.

[0066] The average resistance value of Example 3 is reduced by 30.24% compared with that of Comparative Example 1, which greatly improves the performance parameters of the chip.

[0067] The examples of this specific embodiment are all preferred embodiments of this application and are not intended to limit the scope of protection of this application. Identical components are represented by the same reference numerals. Therefore, any equivalent changes made based on the structure, shape, and principle of this application should be included in the scope of protection of this application.

Claims

1. High fundamental frequency MESA chip, characterized by: include: The sheet body has a rectangular outer periphery, and includes a vibrating portion formed by etching depressions on both sides, and a fixed portion integrally provided with the vibrating portion, wherein the distance between the vibrating portion and the free end of the fixed portion is defined as L1, and the distance between the vibrating portion and the dispensing end of the fixed portion is defined as L2, and 1<L1 / L2≤1.3; A pair of electrodes, each electrode includes an excitation electrode disposed on two opposite sides of the vibration part, and an extraction electrode connected to the excitation electrode and led to the dispensing end of the fixing part.

2. The high fundamental frequency MESA chip according to claim 1, characterized in that: 1.2≤L1 / L2≤1.

3.

3. The high fundamental frequency MESA chip according to claim 1, characterized in that: The shape of the vibration part is one of a circle, an ellipse and a stadium.

4. The high fundamental frequency MESA chip according to any one of claims 1 to 3, characterized in that: The excitation electrode is circular and is coaxially arranged with the vibration part.

5. The high fundamental frequency MESA chip according to claim 4, characterized in that: The lead-out electrode includes a fan-shaped portion connected to the excitation electrode, and a dispensing portion connected to the fan-shaped portion and arranged at the dispensing end of the fixed portion, wherein the dispensing portion includes a pair of surface layers laid on both sides of the sheet body, and a pair of end surface layers used to connect the surface layers and laid on the end sides of the sheet body.

6. The high fundamental frequency MESA chip according to any one of claims 1 to 3, characterized in that: The aspect ratio of the sheet is 1.5-1.7:

1.

7. The high fundamental frequency MESA chip according to claim 6, characterized in that: The aspect ratio of the sheet is 1.6:

1.

8. The high fundamental frequency MESA chip according to any one of claims 1 to 3, characterized in that: The thickness of the vibration part is 3.3-4.7 μm.

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