Constant-temperature MEMS resonator integrated with temperature sensing function

Abstract

The invention provides a constant-temperature MEMS resonator integrated with a temperature sensor, relates to the technical field of temperature regulation of MEMS resonators, aims to realize constant-temperature control, and comprises at least one heating resistance wire, at least one temperature sensor and an MEMS resonator, the heating resistance wire, the temperature sensor and the MEMS resonator are arranged on the same doped silicon structure layer and are packaged together; the temperature sensor is used for detecting the real-time temperature of the MEMS resonator; and the heating resistance wire is used for heating the MEMS resonator according to the real-time temperature, so that the working temperature of the MEMS resonator is constant. The invention has the advantage of ensuring the frequency stability of the resonator.

Description

Technical Field

[0001] The invention relates to the technical field of temperature regulation of MEMS resonators, and in particular to a constant-temperature MEMS resonator with integrated temperature sensing. Background Art

[0002] Compared with traditional quartz crystal resonators, MEMS resonators have the advantages of small size, shock and vibration resistance, high sensitivity, easy integration, low power consumption and low electromagnetic radiation, and fast delivery. They completely replace and surpass traditional quartz crystal resonators in terms of product form, function, performance and cost, and can be more widely used in automotive electronics, 5G communications, satellite navigation, national defense and military, aerospace, and the Internet of Things. They have extremely broad application prospects and strong incremental demand.

[0003] The main disadvantage of MEMS resonators is that the resonant frequency is affected by the external temperature. This is because the spring softening effect produced by the temperature coefficient of elasticity (TCE) of silicon can cause the temperature coefficient of frequency (TCF) of silicon MEMS resonators to be about -30ppm / ℃. Therefore, the resonant frequency drift of uncompensated silicon MEMS resonators in the full industrial range of -40℃ to +85℃ is as high as 3750ppm, which is unacceptable in practical applications.

[0004] Therefore, the influence of constant temperature control on the frequency of the MEMS resonator is an issue that needs to be urgently addressed in the art, so as to ensure the frequency stability of the resonator. Summary of the invention

[0005] The object of the present invention is to provide a constant temperature MEMS resonator with integrated temperature sensing, which can realize constant temperature control to ensure the frequency stability of the resonator.

[0006] The present invention is achieved through the following technical solutions:

[0007] A constant temperature MEMS ring resonator with integrated temperature sensing, comprising at least one heating resistor wire, at least one temperature sensor and a MEMS resonator;

[0008] The heating resistance wire, the temperature sensor and the MEMS resonator are arranged in the same doped silicon structure layer and packaged together;

[0009] The temperature sensor is used to detect the real-time temperature of the MEMS resonator;

[0010] The heating resistor wire is used to heat the MEMS resonator according to the real-time temperature, thereby making the operating temperature of the MEMS resonator constant.

[0011] Preferably, the MEMS resonator comprises at least one ring resonance component, and the resonance component comprises a driving component, a detection component, a coupling beam and an anchor point;

[0012] The driving component and the detecting component are connected via the coupling beam, and the coupling beam is fixed on the anchor point.

[0013] Preferably, the driving assembly comprises a positive driving electrode, a first vibrating mechanical structure and a negative driving electrode;

[0014] The first vibration mechanical structure is arranged on the outer circle of the negative driving electrode, and the positive driving electrode is arranged on the outer circle of the first vibration mechanical structure.

[0015] Preferably, the detection assembly comprises a positive detection electrode, a second vibrating mechanical structure and a negative detection electrode;

[0016] The second vibrating mechanical structure is disposed on an outer circle of the negative detection electrode, and the positive detection electrode is disposed on an outer circle of the second vibrating mechanical structure.

[0017] Preferably, the number of the temperature sensor and the number of the heating resistance wires are both 2;

[0018] The first temperature sensor, the second temperature sensor, the first heating resistor wire and the second heating resistor wire are arranged in 2×2; the first temperature sensor and the second temperature sensor are located at the upper left and lower right respectively, and the second heating resistor wire and the first heating resistor wire are located at the upper right and lower left respectively.

[0019] Preferably, the method for heating the MEMS resonator by the heating resistance wire according to the real-time temperature comprises the following steps:

[0020] periodically acquiring a first measurement value of the first temperature sensor and a second measurement value of the second temperature sensor;

[0021] A first sequence is obtained by arranging the first measurement values ​​at N consecutive time points in time series, and a second sequence is obtained by arranging the second measurement values ​​at N consecutive time points in time series;

[0022] The first heating resistor wire and the second heating resistor wire are turned on or off according to the first sequence and the second sequence.

[0023] Preferably, the method for determining whether to turn on or off the first heating resistor wire and the second heating resistor wire according to the first sequence and the second sequence is:

[0024] Get the first evaluation parameters of the first and second sequences respectively:

[0025]

[0026] Get the second evaluation parameters of the first sequence and the second sequence respectively:

[0027]

[0028] Among them, J1 i is the second evaluation parameter of the i-th sequence, represents the nth measurement value in the i-th sequence, is the floor operator;

[0029] Preset a first evaluation upper limit parameter threshold, a first evaluation middle parameter threshold, a first evaluation lower limit parameter threshold, and a second evaluation parameter threshold;

[0030] If the first evaluation parameter of the first sequence is less than the first evaluation parameter lower limit threshold, the first heating resistor is turned on; if the first evaluation parameter of the second sequence is less than the first evaluation parameter lower limit threshold, the second heating resistor is turned on;

[0031] The heating process continuously acquires the first sequence and the second sequence in real time to determine whether to turn off the first heating resistor wire and / or the second heating resistor wire.

[0032] Preferably, the method for determining whether to turn off the first heating resistor wire and / or the second heating resistor wire is:

[0033] When one of the first heating resistor wire and the second heating resistor wire is turned on:

[0034] If the first evaluation parameter of the i-th sequence reaches the first evaluation upper limit parameter threshold, the i-th heating resistor wire is turned off;

[0035] When the first heating resistor and the second heating resistor are turned on at the same time:

[0036] If the first evaluation parameter of the i-th sequence reaches the first evaluation intermediate parameter threshold and the second evaluation parameter of the i-th sequence is greater than the second evaluation parameter threshold, the i-th heating resistor wire is turned off; when the first evaluation parameters of the first heating resistor wire and the second heating resistor wire both reach the first evaluation upper limit parameter threshold, the other heating resistor wire is turned off.

[0037] Preferably, the temperature sensor is a thermistor.

[0038] Preferably, the value acquisition method of the temperature sensor adopts a four-wire resistance measurement method.

[0039] The technical solution of the present invention has at least the following advantages and beneficial effects:

[0040] The present invention arranges a temperature sensor and a heating resistor on the basis of the MEMS resonator, and the temperature monitoring of the MEMS resonator can be realized through simple improvement;

[0041] The present invention provides multiple temperature sensors and heating resistors, which helps to achieve comprehensive temperature monitoring of more points of the MEMS resonator and further improve the control of temperature stability;

[0042] When the present invention performs temperature monitoring based on multiple sensors and heating resistors, the real-time temperature and trend conditions are detected simultaneously, and multiple thresholds are set for multi-condition control, so as to reduce the energy consumption of the heating resistor as much as possible while accurately achieving constant temperature control;

[0043] The present invention has reasonable design and simple structure, does not require improvement in the design of the resonator itself and is therefore easy to manufacture. The temperature control processing calculation power is low, the consumption of the heating resistance wire is reduced as much as possible, and it has a very high cost-effectiveness. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 A schematic structural diagram of a constant temperature MEMS resonator with integrated temperature sensing provided by an embodiment of the present invention;

[0045] Figure 2 A schematic structural diagram of another temperature-controlled MEMS resonator with integrated temperature sensing provided by an embodiment of the present invention;

[0046] Figure 3 A wiring diagram of a four-wire resistance measurement method provided by an embodiment of the present invention;

[0047] Icon: 101 - negative driving electrode, 102 - first vibrating mechanical structure, 103 - positive driving electrode, 104 - coupling beam, 105 - positive detection electrode, 106 - second vibrating mechanical structure, 107 - negative detection electrode, 108 - anchor point. DETAILED DESCRIPTION

[0048] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0049] Example 1

[0050] This embodiment provides a constant temperature MEMS resonator with integrated temperature sensing, see Figure 1-Figure 2 , including at least one heating resistor wire, at least one temperature sensor and a MEMS resonator;

[0051] The heating resistance wire, the temperature sensor and the MEMS resonator are arranged in the same doped silicon structure layer and packaged together;

[0052] The temperature sensor is used to detect the real-time temperature of the MEMS resonator;

[0053] The heating resistor wire is used to heat the MEMS resonator according to the real-time temperature, thereby making the operating temperature of the MEMS ring resonator constant.

[0054] In this embodiment, the MEMS resonator includes at least one resonant component, and the resonant component includes a driving component, a detection component, a coupling beam 104 and an anchor point 108;

[0055] The driving assembly and the detecting assembly are connected via the coupling beam 104 , and the coupling beam 104 is fixed on the anchor point 108 .

[0056] Further, the driving assembly includes a positive driving electrode 103, a first vibration mechanical structure 102 and a negative driving electrode 101;

[0057] The first vibration ring 102 is disposed on the outer ring of the negative driving electrode 101 , and the positive driving electrode 103 is disposed on the outer ring of the first vibration mechanical structure 102 .

[0058] On the other hand, the detection assembly includes a positive detection electrode 105, a second vibrating mechanical structure 106 and a negative detection electrode 107;

[0059] The second vibration mechanical structure 106 is disposed on the outer circle of the negative detection electrode 107 , and the positive detection electrode 105 is disposed on the outer circle of the mechanical structure of the second vibration ring 10 .

[0060] A case example Figure 1 The above-mentioned device comprises a heating resistor wire and a temperature sensor, which are respectively arranged on both sides of the coupling beam 104 .

[0061] Based on the technical solution of this embodiment, driving electrodes are arranged on the inside and outside of the first vibration mechanical structure 102. When an AC voltage is applied to the positive and negative driving electrodes, an electrostatic force will be generated between the driving electrodes and the first vibration mechanical structure 102. When the frequency of the AC voltage is consistent with the resonant frequency of the first vibration mechanical structure 102 itself, the first vibration mechanical structure 102 will resonate, thereby changing the capacitance between the detection electrode at the detection end and the second vibration mechanical structure 106, and a current signal will be output at the detection end. Specifically, the vibration frequency of the vibration ring is determined by the inner and outer radii of the ring, as well as the material. The dominant resonant mode of the circular ring structure is the breathing mode in the body vibration mode, that is, the ring structure stretches or contracts outward with the center of the circle as the center. The frequency of the ring resonator when vibrating in the breathing mode can be expressed as:

[0062]

[0063] Where f0 is the resonant frequency, E is the Young's modulus, ρ is the mass density of the material of the vibration ring, and r o and r i are the outer radius and inner radius of the vibration ring respectively, and w is the width of the resonance ring.

[0064] Based on the above, one end of the coupling beam 104 is connected and coupled to the vibration ring, and the other end is the anchor point 108. In order to reduce energy loss, the length of the coupling beam 104 is designed to be 1 / 4 of the resonant wavelength of the resonator. When the vibration ring resonates in the breathing mode, the coupling beam 104 vibrates in the longitudinal extension mode, and the vibration frequency is consistent with the resonant frequency of the vibration ring, so good coupling can be performed at the connection, reducing the damping of the anchor point 108.

[0065] At the same time, the coordination of temperature sensors and heating resistors can achieve constant temperature control of the entire MEMS, which helps to enhance the stability of device operation.

[0066] Example 2

[0067] This embodiment is based on the technical solution of Embodiment 1 and further explains the specific method of constant temperature monitoring.

[0068] As a preferred solution of this embodiment, refer to Figure 2 , the number of the temperature sensor and the number of the heating resistance wires are both 2;

[0069] The first temperature sensor, the second temperature sensor, the first heating resistor wire, and the second heating resistor wire are arranged in a 2×2 pattern; the first temperature sensor and the second temperature sensor are located at the upper left and lower right, respectively, and the second heating resistor wire and the first heating resistor wire are located at the upper right and lower left, respectively. In this case, the first temperature sensor and the first heating resistor wire are located on the side close to the drive component, and the second temperature sensor and the second heating resistor wire are located on the side of the detection component. The two temperature sensors and the two heating resistor wires can collaborate to monitor the temperature at both ends, achieving more stable MEMS constant temperature regulation.

[0070] In this embodiment, the method for heating the MEMS resonator according to the real-time temperature by the heating resistance wire comprises the following steps:

[0071] periodically acquiring a first measurement value of the first temperature sensor and a second measurement value of the second temperature sensor;

[0072] A first sequence is obtained by arranging the first measurement values ​​at N consecutive time points in time series, and a second sequence is obtained by arranging the second measurement values ​​at N consecutive time points in time series;

[0073] The first heating resistor wire and the second heating resistor wire are turned on or off according to the first sequence and the second sequence.

[0074] Further, the method for determining whether to turn on or off the first heating resistor wire and the second heating resistor wire according to the first sequence and the second sequence is:

[0075] Get the first evaluation parameters of the first and second sequences respectively:

[0076]

[0077] Get the second evaluation parameters of the first sequence and the second sequence respectively:

[0078]

[0079] Among them, J1 i is the second evaluation parameter of the i-th sequence, represents the nth measurement value in the i-th sequence, is the floor operator;

[0080] Preset a first evaluation upper limit parameter threshold, a first evaluation middle parameter threshold, a first evaluation lower limit parameter threshold, and a second evaluation parameter threshold;

[0081] If the first evaluation parameter of the first sequence is less than the first evaluation parameter lower limit threshold, the first heating resistor is turned on; if the first evaluation parameter of the second sequence is less than the first evaluation parameter lower limit threshold, the second heating resistor is turned on;

[0082] The heating process continuously acquires the first sequence and the second sequence in real time to determine whether to turn off the first heating resistor wire and / or the second heating resistor wire.

[0083] On the other hand, the method for determining whether to turn off the first heating resistor wire and / or the second heating resistor wire is:

[0084] When one of the first heating resistor wire and the second heating resistor wire is turned on:

[0085] If the first evaluation parameter of the i-th sequence reaches the first evaluation upper limit parameter threshold, the i-th heating resistor wire is turned off;

[0086] When the first heating resistor and the second heating resistor are turned on at the same time:

[0087] If the first evaluation parameter of the i-th sequence reaches the first evaluation intermediate parameter threshold and the second evaluation parameter of the i-th sequence is greater than the second evaluation parameter threshold, the i-th heating resistor wire is turned off; when the first evaluation parameters of the first heating resistor wire and the second heating resistor wire both reach the first evaluation upper limit parameter threshold, the other heating resistor wire is turned off.

[0088] Through the control of this embodiment, the switches of the two heating resistors can be flexibly adjusted under the monitoring conditions of two groups of temperature sensors to ensure the temperature requirements while minimizing the situation where the two heating resistors are turned on at the same time, thereby ensuring the temperature control effect and reducing energy consumption.

[0089] Example 3

[0090] This embodiment is based on the technical solution of Embodiment 1 and further describes the temperature sensor.

[0091] As a preferred solution, the temperature sensor is a thermistor.

[0092] Furthermore, the value acquisition method of the temperature sensor adopts a four-wire resistance measurement method.

[0093] For example, the resistance value R of a resistor is as follows:

[0094]

[0095] Where l and S are the length and cross-sectional area of ​​the resistor, respectively, and σ is the conductivity of the resistor material.

[0096] Further:

[0097] σ=q(nμ e +pμ);

[0098] Where q is the electron charge, n is the electron density, μ e is the electron mobility, p is the hole density, and μ is the hole mobility. Specifically, the carrier concentration and mobility are related to temperature and doping concentration. Both factors affect the resistance value of the thermistor, so the temperature can be obtained from the resistance value.

[0099] The four-wire resistance measurement method adopted in this embodiment is to separate the leads for inputting current from the leads for measuring the voltage value at both ends of the resistor to be measured. Two of the leads are used to provide a constant current, and the other two are used to measure the voltage value at both ends of the resistor to be measured. By doing so, the resistance of the probe itself and the contact resistance generated in the current routing can be ignored, leaving only the resistance of the probe itself and the contact resistance generated in the voltmeter routing. Since the input impedance of the voltmeter is very large and the current flowing through is very small, the voltage drop caused can be ignored compared to the resistor to be measured, which greatly improves the measurement accuracy.

[0100] A wiring method for four-wire resistance measurement Figure 3 , RL is the thermistor to be measured, R1 and R2 are the additional impedances generated by the current leads, and R3 and R4 are the additional impedances generated by the voltage leads. Thermistors are resistive temperature sensors based on the thermal properties of silicon semiconductor materials. Their output resistance is related to temperature. Real-time monitoring of the operating temperature is achieved by measuring their serpentine semiconductor thermistors.

[0101] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A constant temperature MEMS resonator with integrated temperature sensing, characterized in that: It includes at least one heating resistor wire, at least one temperature sensor and a MEMS resonator; The heating resistance wire, the temperature sensor and the MEMS resonator are arranged in the same doped silicon structure layer and packaged together; The temperature sensor is used to detect the real-time temperature of the MEMS resonator; The heating resistor wire is used to heat the MEMS resonator according to the real-time temperature, thereby making the operating temperature of the MEMS ring resonator constant.

2. A constant temperature MEMS resonator with integrated temperature sensing according to claim 1, characterized in that: The MEMS resonator includes at least one resonant component, and the resonant component includes a driving component, a detection component, a coupling beam and an anchor point; The driving component and the detecting component are connected via the coupling beam, and the coupling beam is fixed on the anchor point.

3. A constant temperature MEMS resonator with integrated temperature sensing according to claim 2, characterized in that: The driving assembly includes a positive driving electrode, a first vibrating mechanical structure and a negative driving electrode; The first vibration mechanical structure is arranged on the outer circle of the negative driving electrode, and the positive driving electrode is arranged on the outer circle of the first vibration mechanical structure.

4. The constant temperature MEMS resonator with integrated temperature sensing according to claim 3, characterized in that: The detection assembly includes a positive detection electrode, a second vibrating mechanical structure, and a negative detection electrode; The second vibrating mechanical structure is disposed on an outer circle of the negative detection electrode, and the positive detection electrode is disposed on an outer circle of the second vibrating mechanical structure.

5. The constant temperature MEMS resonator with integrated temperature sensing according to claim 1, characterized in that: The number of the temperature sensor and the number of the heating resistance wires are both 2; The first temperature sensor, the second temperature sensor, the first heating resistor wire and the second heating resistor wire are arranged in 2×2; the first temperature sensor and the second temperature sensor are located at the upper left and lower right respectively, and the second heating resistor wire and the first heating resistor wire are located at the upper right and lower left respectively.

6. The constant temperature MEMS resonator with integrated temperature sensing according to claim 5, characterized in that: The method for heating the MEMS resonator according to the real-time temperature by the heating resistance wire comprises the following steps: periodically acquiring a first measurement value of the first temperature sensor and a second measurement value of the second temperature sensor; A first sequence is obtained by arranging the first measurement values ​​at N consecutive time points in time series, and a second sequence is obtained by arranging the second measurement values ​​at N consecutive time points in time series; The first heating resistor wire and the second heating resistor wire are turned on or off according to the first sequence and the second sequence.

7. A constant temperature MEMS resonator with integrated temperature sensing according to claim 6, characterized in that: The method for determining the opening or closing of the first heating resistor wire and the second heating resistor wire according to the first sequence and the second sequence is: Get the first evaluation parameters of the first and second sequences respectively: Get the second evaluation parameters of the first sequence and the second sequence respectively: Among them, J1 i is the second evaluation parameter of the i-th sequence, represents the nth measurement value in the i-th sequence, is the floor operator; Preset a first evaluation upper limit parameter threshold, a first evaluation middle parameter threshold, a first evaluation lower limit parameter threshold, and a second evaluation parameter threshold; If the first evaluation parameter of the first sequence is less than the first evaluation parameter lower limit threshold, the first heating resistor is turned on; if the first evaluation parameter of the second sequence is less than the first evaluation parameter lower limit threshold, the second heating resistor is turned on; The heating process continuously acquires the first sequence and the second sequence in real time to determine whether to turn off the first heating resistor wire and / or the second heating resistor wire.

8. The constant temperature MEMS resonator with integrated temperature sensing according to claim 7, characterized in that: The method for determining whether to turn off the first heating resistor wire and / or the second heating resistor wire is: When one of the first heating resistor wire and the second heating resistor wire is turned on: If the first evaluation parameter of the i-th sequence reaches the first evaluation upper limit parameter threshold, the i-th heating resistor wire is turned off; When the first heating resistor wire and the second heating resistor wire are turned on at the same time: If the first evaluation parameter of the i-th sequence reaches the first evaluation intermediate parameter threshold and the second evaluation parameter of the i-th sequence is greater than the second evaluation parameter threshold, the i-th heating resistor wire is turned off; when the first evaluation parameters of the first heating resistor wire and the second heating resistor wire both reach the first evaluation upper limit parameter threshold, the other heating resistor wire is turned off.

9. The constant temperature MEMS resonator with integrated temperature sensing according to claim 1, characterized in that: The temperature sensor is a thermistor.

10. The constant temperature MEMS resonator with integrated temperature sensing according to claim 9, characterized in that: The value acquisition method of the temperature sensor adopts a four-wire resistance measurement method.

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