Wafer structure with small electrode and small TS value and resonator

Abstract

The utility model discloses a small electrode small TS value wafer structure and a resonator, comprising a quartz wafer, the quartz wafer is a rectangular structure, the size of the long side A of the quartz wafer is 1.3 mm, the size of the short side B of the quartz wafer is 1.0 mm, the upper surface and the lower surface of the quartz wafer are plated with metal films, the metal films are in the shape of connection of the upper electrode and the lower electrode, and the upper electrode and the lower electrode are in the same shape. According to the technical scheme provided by the utility model, the length and the width of the quartz crystal are changed, and the size of the metal film on the quartz crystal is correspondingly changed, so that the changed size can meet the energy trapping theory, good parasitic control can be realized, the stability of the quartz crystal is improved, and the service life of the quartz crystal is prolonged. And the stability of the resonator using the quartz crystal is further improved.

Description

Technical Field

[0001] The utility model relates to the technical field of resonators, and in particular to a chip structure with small electrodes and small TS values ​​and a resonator. Background Art

[0002] As the use of quartz crystal resonator 2520 specification SMD patch crystals becomes more and more extensive, the crystal characteristic parameters are becoming more and more stringent, especially the control of frequency difference and the performance and stability of the crystal. It is required that the frequency of the crystal be less affected by external stray capacitance, so that the smaller the sensitivity (TS) value is, the better without affecting the characteristic parameters of the crystal.

[0003] Sensitivity (TS) indicates the change in frequency as the load capacitance changes. The smaller the load capacitance, the larger the TS, and the greater the frequency change due to the influence of external stray capacitance. The TS value is proportional to the dynamic capacitance C1 value and inversely proportional to the static capacitance C0 value; C0 and C1 are proportional to the electrode area, so the smaller the effective area of ​​the electrode, the smaller the C0 and C1 values ​​are, and the smaller the TS value is. Under the same load requirements, the most effective way to reduce the TS value is to reduce the effective area of ​​the electrode. For example, the conventional design size of the SMD 252026M 7PF specification chip crystal is: 1.60*1.25, and the effective area of ​​the optimal electrode design is: 1.3mm 2 The TS value is about 27ppm / pF. Under the same load, the customer requires a TS value of 15ppm / pF, so the effective area of ​​the electrode must be designed to be 0.6mm 2 But the size is 1.60*1.25, and the effective area of ​​the electrode is designed to be 0.6mm 2 According to the "energy trap" principle of AT, it is easy to cause parasitic coupling, resulting in poor crystal performance, and in severe cases, the entire machine may not work properly. Utility Model Content

[0004] 1. Technical problems to be solved by the utility model

[0005] The technical problem to be solved by the utility model is to provide a wafer structure and a resonator with a small electrode and a small TS value, which solves the problem that the existing quartz crystal resonator is prone to parasitic coupling, resulting in poor crystal performance.

[0006] 2. Technical solution

[0007] In order to solve the above problems, the technical solution provided by the utility model is:

[0008] A chip structure with a small electrode and a small TS value comprises a quartz chip. The quartz chip is a rectangular structure. The size of the long side A of the quartz chip is 1.3 mm, and the size of the short side B of the quartz chip is 1.0 mm.

[0009] Furthermore, the upper and lower surfaces of the quartz wafer are plated with metal films.

[0010] Furthermore, the metal film is in a shape where upper and lower electrodes are connected.

[0011] Furthermore, the metal film is divided into a silver-plated layer and a chrome-plated layer. A chrome-plated layer is firstly plated on the upper and lower surfaces of the quartz wafer, and then a silver-plated layer is plated on the chrome-plated layer. The chrome-plated layer is located between the quartz wafer and the silver-plated layer.

[0012] Furthermore, the metal films on the upper and lower surfaces of the quartz wafer are electrically connected to the electrodes.

[0013] A quartz crystal resonator comprises a resonator using the wafer structure.

[0014] 3. Beneficial effects

[0015] Compared with the prior art, the technical solution provided by the utility model has the following beneficial effects:

[0016] The technical solution provided by the utility model changes the length and width of the quartz crystal, and accordingly changes the size of the metal film on the quartz crystal, so that the changed size can meet the energy trap theory, enable good parasitic control, improve the stability of the quartz crystal, and further improve the stability of the resonator using the quartz crystal. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a schematic diagram of the dimensions of the quartz wafer proposed in the utility model;

[0018] Figure 2 A top view of the resonator proposed in the utility model;

[0019] Figure 3 This is a front view of the resonator proposed by the utility model. DETAILED DESCRIPTION

[0020] In order to further understand the content of the utility model, the utility model is described in detail in conjunction with the accompanying drawings and embodiments.

[0021] The present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It is understood that the specific embodiments described herein are only used to explain the relevant utility model, rather than to limit the utility model. It should also be noted that, for the convenience of description, only the parts related to the utility model are shown in the accompanying drawings. The words "first", "second", etc. described in the present utility model are set for the convenience of describing the technical solution of the present utility model, and have no specific limiting effect. They are all general references and do not constitute a limiting effect on the technical solution of the present utility model. It should be noted that, in the absence of conflict, the embodiments and features in the embodiments in the present application can be combined with each other. In the description of the present utility model, it should be noted that the orientation or position relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inside", "outside", etc. is based on the orientation or position relationship shown in the accompanying drawings, which is only for the convenience of describing the present utility model and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present utility model. In addition, the terms "first", "second", and "third" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance. Unless otherwise clearly specified and limited, the terms "installed", "connected" and "connected" 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, or it can be a connection between the insides of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present utility model can be understood according to specific circumstances. Multiple technical solutions in the same embodiment, and multiple technical solutions in different embodiments, can be arranged and combined to form new technical solutions that do not have contradictions or conflicts, all of which are within the scope of protection required by the present utility model.

[0022] Example

[0023] Combined with Figure 1-3

[0024] Example 1

[0025] A chip structure with small electrodes and small TS value comprises a quartz chip 4 and a metal film 5. The metal film 5 is plated on the upper and lower surfaces of the quartz chip 4 and is symmetrically arranged with the quartz chip 4 as the center.

[0026] The metal film 4 is composed of a silver-plated layer and a chrome-plated layer. The chrome-plated layer is in contact with the quartz wafer 4 , and the silver-plated layer is plated on the chrome-plated layer.

[0027] The quartz wafer 4 is a rectangular structure, and an electrode is provided on the short side of any side of the quartz wafer 4. The metal films 5 on the upper and lower surfaces of the quartz wafer 4 share one electrode, and the metal films 5 on the upper and lower surfaces of the quartz wafer 4 are in a shape where the upper and lower electrodes are connected.

[0028] The upper and lower surfaces of the quartz wafer 4 are first plated with a chrome layer, and then a silver layer is plated on the chrome layer. The chrome layer is located between the quartz wafer and the silver layer.

[0029] The metal film 4 is electrically connected to the electrode.

[0030] The size of the long side A of the quartz wafer 4 is 1.3 mm, and the size of the short side B of the quartz wafer 4 is 1.0 mm.

[0031] Due to the existing conventional 2520 specification wafer size, the A dimension of the quartz wafer 4 is 1.6mm and the B dimension is 1.25mm. According to the "energy trap" principle of AT, the size of the existing conventional 2520 specification wafer is prone to parasitic coupling, resulting in poor crystal performance.

[0032] In this embodiment, the size of the long side A of the quartz wafer 4 is 1.3 mm, and the size of the short side B of the quartz wafer 4 is 1.0 mm, which can achieve good parasitic control and improve the stability of the crystal.

[0033] The principle is: first, the coupling of the surface shear and bending vibration of the length of the chip size and the surface shear vibration coupling of the width are calculated; secondly, the calculation formula of the electrode size and the return coefficient is determined according to the energy trap theory.

[0034] To verify the coupling between length and high-order overtones of surface shear vibration, there is an empirical formula:

[0035]

[0036] Where: n: number of harmonics along the length X direction, n = 3, 5, 7...odd number

[0037] To verify the coupling of length bending vibration, there is an empirical formula:

[0038]

[0039] Where n: the number of overtones of bending vibration along the length X direction, n = 2, 4, 6... even number

[0040] Verify the coupling of surface shear vibration:

[0041]

[0042] Where: n Fs: The overtone number of the surface shear vibration along the width Z' axis direction, n = 2, 4, 6... positive integer

[0043] p: Density of quartz crystal = 2.65*10 3 Kg / m 3

[0044] To verify the coupling of width plane shear vibration, there is a formula:

[0045]

[0046] Where: n Ws : The number of harmonics along the width Z' axis, n = 2, 4, 6... positive integer

[0047] To verify the coupling of width plane shear vibration, there is an empirical formula:

[0048]

[0049] Where: n = 3, 5, 7...odd number

[0050] Determining the electrode size and return coefficient based on the energy trap theory can achieve good parasitic control. The electrode sizes lxe and lze should meet the following requirements:

[0051]

[0052]

[0053]

[0054] Where: lxe represents the length dimension of the electrode (mm), lze represents the width dimension of the electrode (mm), t represents the thickness of the quartz wafer (mm), n represents the number of overtones, fF represents the quartz wafer corrosion frequency (KHz), and fn represents the nominal frequency (KHz).

[0055] Substituting the above formula into the value that the long side A of the quartz wafer 4 is 1.3 mm and the short side B of the quartz wafer 4 is 1.0 mm, it can be concluded that the above technical solution can well control parasitic coupling and improve the stability of the crystal.

[0056] Example 2

[0057] Since the dimensions of the long side A and the short side B of the quartz wafer are changed in Implementation 1, the base used therewith also needs to be changed synchronously.

[0058] A quartz crystal resonator base for a small-sized chip comprises a base 1, a conductive adhesive coating area 2, a supporting platform 3, a metal ring plane 7, a metal cover plate 8 and a silver-plated pad 9.

[0059] The conductive glue coated area 2 is provided with two electrode structures corresponding to the metal film 5 respectively. One end of the quartz chip 4 used for electrically connecting the metal film 5 to the electrode is mounted on the conductive glue coated area 2. The metal film 5 and the conductive glue coated area 2 are electrically connected through the conductive glue 6.

[0060] The support platform 3 is arranged on the base 1 for supporting the other end of the quartz chip 4. The distance A between the support platform 3 and the adjacent edges of the conductive glue coating area 2 is 1.05 mm, and the width B of the support platform is 0.3 mm. The distance A between the support platform 3 and the adjacent edges of the conductive glue coating area 2 and the width B of the support platform 3 are corresponding changes made to match the size changes of the quartz chip 4.

[0061] The base 1 is further provided with a metal ring plane 7 , which is arranged around the support platform 3 and the outer side of the conductive adhesive coating area 2 .

[0062] A metal cover plate 8 is disposed on the metal ring plane 7 . The metal cover plate 8 covers the metal ring plane 7 . The metal ring plane 7 , the metal cover plate 8 and the base 1 form a closed cavity for mounting the quartz wafer 4 .

[0063] A plurality of silver-plated pads 9 are provided at the bottom of the base 1 .

[0064] The silver-plated pad 9 includes at least two incommunicative silver coatings, and the two silver coatings are respectively connected to two electrodes of the quartz wafer 4 .

[0065] Example 3

[0066] A base quartz crystal resonator with a small-sized chip, wherein the quartz chip 4 of Example 1 is installed in a closed cavity formed by the metal ring plane 7, the metal cover plate 8 and the base 1 in Example 2, and the quartz chip 4 is mounted on the conductive glue coating area 2 and the supporting platform 3, thereby forming a complete quartz crystal resonator.

[0067] The above schematically describes the present invention and its implementation methods, which are not restrictive. The drawings show only one implementation method of the present invention, and the actual structure is not limited thereto. Therefore, if ordinary technicians in this field are inspired by it and design structural methods and embodiments similar to the technical solution without creativity without departing from the purpose of the present invention, they should all fall within the protection scope of the present invention.

Claims

1. A wafer structure with small electrodes and small TS value, characterized in that: The invention comprises a quartz wafer, wherein the quartz wafer is a rectangular structure, the size of the long side A of the quartz wafer is 1.3 mm, and the size of the short side B of the quartz wafer is 1.0 mm.

2. The wafer structure with small electrode and small TS value according to claim 1, characterized in that: The upper and lower surfaces of the quartz wafer are plated with metal films.

3. The wafer structure with small electrode and small TS value according to claim 2, characterized in that: The metal film is in a shape where upper and lower electrodes are connected.

4. The wafer structure with small electrode and small TS value according to claim 2, characterized in that: The metal film is divided into a silver-plated layer and a chrome-plated layer. A chrome-plated layer is firstly plated on the upper and lower surfaces of the quartz wafer, and then a silver-plated layer is plated on the chrome-plated layer. The chrome-plated layer is located between the quartz wafer and the silver-plated layer.

5. The wafer structure with small electrode and small TS value according to claim 2, characterized in that: The metal films on the upper and lower surfaces of the quartz wafer are electrically connected to the electrodes.

6. A quartz crystal resonator, characterized in that: A wafer structure comprising a small electrode and a small TS value as described in any of claims 1-5.

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