CN116659740A - MEMS device vacuum measurement method, device, computer equipment and storage medium - Google Patents

Abstract

The application relates to a MEMS device vacuum degree measuring method, a device, computer equipment, a storage medium and a computer program product. The method comprises the following steps: acquiring a quality factor of the MEMS device under the vacuum packaging condition; acquiring quality factors of the MEMS device under different air pressure conditions; fitting according to quality factors under different air pressure conditions to obtain a fitting equation; and calculating based on the fitting equation and the quality factor under the vacuum packaging condition to obtain the intracavity vacuum degree of the MEMS device. According to the whole scheme, by measuring the quality factors of the MEMS device under different air pressure conditions and fitting according to the quality factors under different air pressure conditions, a fitting equation is obtained, the correlation between the air pressure and the quality factors can be accurately described by the fitting equation, and then the calculation is carried out according to the fitting equation and the quality factors under vacuum packaging conditions, so that the intracavity vacuum degree of the MEMS device can be accurately obtained.

Description

MEMS device vacuum measurement method, device, computer equipment and storage medium

technical field

The present application relates to the technical field of gas detection, in particular to a MEMS device vacuum measurement method, device, computer equipment, storage medium and computer program product.

Background technique

MEMS (Micro Electro Mechanical System), that is, micro mechanical electronic system. MEMS devices generally include micro-actuators, micro-sensors, and signal processing circuits, involving various disciplines such as mechanics, electronics, materials, information, and automatic control. Because MEMS devices are generally manufactured by silicon micromachining technology, hundreds of MEMS chips can be produced in the same batch, and the miniaturization of MEMS chips makes its work energy consumption low, so MEMS devices have low cost and low energy consumption. , small size and other advantages, it is widely used in automotive electronics, medical equipment, geological exploration and aerospace and other fields.

At present, vacuum packaging technology is usually used to improve the performance of MEMS devices. However, the traditional vacuum packaging technology has reliability problems, such as outgassing of packaging materials and leakage of airtightness, resulting in a decrease in the vacuum degree in the sealed cavity of vacuum-packaged MEMS devices. Therefore, it is particularly important to study a method for measuring the vacuum degree in the sealed cavity of vacuum-packaged MEMS devices.

Contents of the invention

Based on this, it is necessary to provide an accurate method, device, computer equipment, computer-readable storage medium and computer program product for measuring the vacuum degree of MEMS devices in view of the above technical problems.

In a first aspect, the present application provides a method for measuring vacuum degree of a MEMS device. The methods include:

Obtain the quality factor of MEMS devices under vacuum packaging conditions;

Obtaining the quality factor of the MEMS device under different air pressure conditions;

Fitting is carried out according to the quality factors under the different air pressure conditions to obtain a fitting equation;

Calculation is performed based on the fitting equation and the quality factor under the vacuum packaging condition to obtain the vacuum degree in the cavity of the MEMS device.

In one of the embodiments, the fitting is performed according to the quality factors under the different air pressure conditions, and the fitting equation obtained includes:

Obtain the correlation between the quality factor and the air pressure, the correlation includes a positive correlation and a negative correlation;

Based on the least square method and the correlation between the quality factor and air pressure, linear fitting is performed on the quality factor under the different air pressure conditions to obtain a fitting equation.

In one of the embodiments, the obtained correlation between the quality factor and air pressure includes:

Get damping expressions for different types of damping;

Based on the damping expressions of the different types of damping, determine the quality factor expression under the influence of different types of damping;

According to the ideal gas state equation and the expression of the quality factor under the influence of different types of damping, the correlation between the quality factor and the air pressure is determined.

In one of the embodiments, the damping expressions for obtaining different types of damping include:

Obtain the compression film damping expression and the synovial film damping expression;

The described damping expression based on the different types of damping, determining the quality factor expression under the influence of different types of damping includes:

Based on the compression film damping expression and the synovial film damping expression, determining a first quality factor expression under the influence of compression film damping and a second quality factor expression under the influence of synovial film damping;

According to the ideal gas state equation and the quality factor expressions under the influence of different types of damping, determining the correlation between the quality factor and the air pressure includes:

Determine the correlation between the first quality factor and air pressure according to the ideal gas state equation and the first quality factor expression;

According to the ideal gas state equation and the second quality factor expression, determine the correlation between the second quality factor and the air pressure;

In a case where the correlation between the first quality factor and air pressure is the same as the correlation between the second quality factor and air pressure, a correlation between the quality factor and air pressure is obtained.

In one of the embodiments, said obtaining the figure of merit of the MEMS device under vacuum packaging conditions comprises:

Based on the frequency sweep method, the quality factor of MEMS devices under the condition of vacuum packaging is obtained.

In one of the embodiments, said obtaining the figure of merit of the MEMS device under vacuum packaging conditions comprises:

Based on the oscillation attenuation method, the quality factor of MEMS devices under vacuum packaging conditions is obtained.

In one of the embodiments, the obtaining the quality factor of the MEMS device under different air pressure conditions includes:

Acquire a set of air pressure, and determine a preset air pressure sequence based on the set of air pressure;

The MEMS device is placed in each air pressure environment in the preset air pressure sequence, and the quality factor of the MEMS device under each air pressure environment condition is obtained.

In the second aspect, the present application also provides a vacuum degree measuring device for MEMS devices. The devices include:

The first acquisition module is used to acquire the quality factor of the MEMS device under vacuum packaging conditions;

The second acquisition module is used to acquire the quality factor of the MEMS device under different air pressure conditions;

A fitting module is used for fitting according to the quality factor under the different air pressure conditions to obtain a fitting equation;

The calculation module is used to perform calculation based on the fitting equation and the quality factor under the vacuum packaging condition to obtain the vacuum degree in the cavity of the MEMS device.

In a third aspect, the present application also provides a computer device. The computer device includes a memory and a processor, the memory stores a computer program, and the processor implements the following steps when executing the computer program:

Obtain the quality factor of MEMS devices under vacuum packaging conditions;

Obtaining the quality factor of the MEMS device under different air pressure conditions;

Fitting is carried out according to the quality factors under the different air pressure conditions to obtain a fitting equation;

Calculation is performed based on the fitting equation and the quality factor under the vacuum packaging condition to obtain the vacuum degree in the cavity of the MEMS device.

In a fourth aspect, the present application also provides a computer-readable storage medium. The computer-readable storage medium has a computer program stored thereon, and when the computer program is executed by a processor, the following steps are implemented:

Obtain the quality factor of MEMS devices under vacuum packaging conditions;

Obtaining the quality factor of the MEMS device under different air pressure conditions;

Fitting is carried out according to the quality factors under the different air pressure conditions to obtain a fitting equation;

Calculation is performed based on the fitting equation and the quality factor under the vacuum packaging condition to obtain the vacuum degree in the cavity of the MEMS device.

In a fifth aspect, the present application also provides a computer program product. The computer program product includes a computer program, and when the computer program is executed by a processor, the following steps are implemented:

Obtain the quality factor of MEMS devices under vacuum packaging conditions;

Obtaining the quality factor of the MEMS device under different air pressure conditions;

Fitting is carried out according to the quality factors under the different air pressure conditions to obtain a fitting equation;

Calculation is performed based on the fitting equation and the quality factor under the vacuum packaging condition to obtain the vacuum degree in the cavity of the MEMS device.

The above method, device, computer equipment, storage medium and computer program product for measuring the vacuum degree of MEMS devices obtain the quality factor of the MEMS device under vacuum packaging conditions; obtain the quality factors of the MEMS device under different air pressure conditions; according to the quality factors under different air pressure conditions The quality factor is fitted to obtain the fitting equation; based on the fitting equation and the quality factor under vacuum packaging conditions, the vacuum degree in the cavity of the MEMS device is obtained. The whole scheme measures the quality factor of the MEMS device under different air pressure conditions, and performs fitting according to the quality factor under different air pressure conditions to obtain a fitting equation. The fitting equation can accurately describe the correlation between air pressure and quality factor, and then according to The fitting equation and the quality factor under vacuum packaging conditions can be calculated to accurately obtain the vacuum degree in the cavity of the MEMS device.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present application or the conventional technology, the following will briefly introduce the accompanying drawings that need to be used in the description of the embodiments or the traditional technology. Obviously, the accompanying drawings in the following description are only the present invention For some embodiments of the application, those skilled in the art can also obtain other drawings based on these drawings without creative work.

Fig. 1 is the application environment figure of MEMS device vacuum degree measuring method in an embodiment;

Fig. 2 is a schematic flow chart of a MEMS device vacuum measurement method in one embodiment;

Fig. 3 is the schematic flow chart of MEMS device vacuum degree measurement in another embodiment;

Figure 4 is a schematic diagram of different types of damping in another embodiment;

FIG. 5 is a schematic flow chart of a method for measuring the degree of vacuum of a MEMS device in yet another embodiment;

Fig. 6 is a schematic diagram of a fitting equation in an embodiment;

Fig. 7 is a structural block diagram of a MEMS device vacuum degree measuring device in an embodiment;

Figure 8 is a diagram of the internal structure of a computer device in one embodiment.

Detailed ways

In order to make the purpose, technical solution and advantages of the present application clearer, the present application will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the present application, and are not intended to limit the present application.

Typical MEMS devices include micro-gyroscopes, micro-accelerometers, oscillators, etc. The core of such devices is the sensing movable structure. They generally use electrical excitation to keep the movable structure of the device in a resonant state. The signal processing circuit detects parameters such as the quality factor and resonant frequency of the resonant oscillator at this time to calculate sensitive information such as external acceleration and angular acceleration.

Generally, vacuum packaging technology is used to improve the performance of MEMS devices. The quality factor of a MEMS device is a key parameter to describe the vibration characteristics of its internal micromechanical structure, and it is related to the performance of the MEMS device such as resolution and sensitivity. The higher the quality factor of the vacuum-packaged MEMS device, the higher the stability of its vibration amplitude and vibration frequency. For example, when the MEMS device is in a resonant state, the requirement for the vacuum degree in the environment is relatively high. The high vacuum environment can reduce the air damping during the movement of the resonant MEMS device, greatly reduce the energy consumption during work, and can also improve the quality factor of the MEMS device, thereby improving its overall performance. Therefore, the sensitive structure of the MEMS device usually adopts vacuum packaging technology to ensure the high vacuum degree in the sealed cavity of the MEMS device.

However, the current vacuum packaging technology has limitations, and there will be problems of outgassing of packaging materials and airtight leakage, resulting in a decrease in the vacuum degree in the sealed cavity of vacuum-packaged MEMS devices. In addition, the volume of the MEMS device is very small, and conventional vacuum gauges and other devices for measuring the vacuum degree cannot measure the vacuum degree in the sealed cavity of the MEMS device.

In order to measure the degree of vacuum in the sealed cavity of MEMS devices, the current methods have relatively large limitations, and indirect measurement methods are usually used. There are two commonly used indirect measurement methods now, one is to use a crystal oscillator as a sensor to measure the inside of the cavity. The method of using the crystal oscillator to measure the vacuum degree in the cavity is based on the principle that the resonant impedance of the crystal oscillator changes with the change of air pressure, and the vacuum degree in the cavity is calculated by measuring the resonant impedance of the crystal oscillator in the sealed cavity. This method needs to package the crystal oscillator and the MEMS chip together into a sealed cavity, which will increase the volume of the MEMS device. In addition, it is necessary to design a crystal oscillator impedance measurement circuit, which increases the complexity of the system.

The other is the Pirani gauge to measure the vacuum inside the cavity of the MEMS device. The measurement principle of the Pirani meter is that when a low-temperature gas molecule collides with a high-temperature solid, it will steal energy from the solid. The vacuum in the cavity can be calculated by calculating the heat captured by the low-temperature gas molecules. This method also needs to package the resistance wires of the Pirani gauge into the sealed cavity together, occupying the narrow space in the sealed cavity. In addition, this method is generally suitable for medium and low vacuum fields, and is not suitable for MEMS devices with higher vacuum requirements.

Therefore, it is particularly important to study a method for measuring the vacuum degree in the sealed cavity of vacuum-packaged MEMS devices. This application is based on the vacuum packaging of MEMS devices. The current MEMS devices generally require vacuum packaging, but the traditional vacuum packaging technology cannot guarantee the vacuum degree in the sealed cavity for a long time. The current vacuum measurement method is generally to package the vacuum measurement elements together into a sealed cavity, which will increase the size of the MEMS device. Therefore, a quality factor-based vacuum measurement method for resonant MEMS devices in a sealed cavity will help MEMS device designers improve the packaging process of vacuum-packaged MEMS devices, study the internal relationship between MEMS performance and vacuum, and then improve Performance of MEMS devices.

The method for measuring the vacuum degree of a MEMS device provided in the embodiment of the present application can be applied to the application environment shown in FIG. 1 . Wherein, the terminal 102 communicates with the MEMS device testing system 104 through the network. The data storage system can be integrated on the server 104, or placed on the cloud or other network servers. The MEMS device testing system 104 measures the quality factor of the MEMS device under vacuum packaging conditions, measures the quality factor of the MEMS device under different air pressure conditions, and sends the quality factor and the quality factor under different air pressure conditions to the terminal 102, and the terminal 102 obtains the MEMS device Quality factor under vacuum packaging conditions; obtain the quality factor of MEMS devices under different air pressure conditions; perform fitting according to the quality factors under different air pressure conditions to obtain a fitting equation; based on the fitting equation and the quality factor under vacuum packaging conditions Perform calculation to obtain the vacuum degree in the cavity of the MEMS device. Among them, the terminal 102 can be, but not limited to, various personal computers, notebook computers, smart phones, tablet computers, Internet of Things devices and portable wearable devices, and the Internet of Things devices can be smart speakers, smart TVs, smart air conditioners, smart vehicle-mounted devices, etc. . Portable wearable devices can be smart watches, smart bracelets, head-mounted devices, and the like.

In one embodiment, as shown in FIG. 2 , a method for measuring the vacuum degree of a MEMS device is provided, and the application of the method to the terminal 102 in FIG. 1 is used as an example for illustration, including the following steps:

Step 200, acquiring the quality factor of the MEMS device under vacuum packaging conditions.

Specifically, since there is a direct correlation between the quality factor of the MEMS device and the vacuum degree in the cavity, the vacuum degree measurement is performed on the MEMS device based on the quality factor. The MEMS device is hermetically packaged in a vacuum environment, and then the MEMS device testing system measures the quality factor of the vacuum-packaged MEMS device when it is intact, and obtains the quality factor Q ₀ , and sends the quality factor to the terminal. The terminal obtains the quality factor of the MEMS device under vacuum packaging conditions.

Step 400, obtaining the quality factor of the MEMS device under different air pressure conditions.

Specifically, the package of the MEMS device is opened to make its internal micromechanical structure communicate with the outside. At this time, the MEMS device is in a non-hermetic package, and the MEMS device after the cover is opened is placed in a vacuum device with adjustable air pressure. At this time, the vacuum degree of the MEMS device is consistent with the vacuum degree of the vacuum device. Adjust the air pressure P in the vacuum chamber of the vacuum device, and then measure the quality factor Q _y of the MEMS device under different air pressure P _x conditions by the MEMS device testing system.

Step 600, performing fitting according to the quality factors under different air pressure conditions to obtain a fitting equation.

Specifically, the air pressure is used as an independent variable, and the reciprocal of the quality factor is used as a dependent variable. Linear fitting is performed according to the quality factors under different air pressure conditions, and a fitting equation representing the linear relationship between air pressure and quality factor is obtained.

Step 800, calculate based on the fitting equation and the quality factor under the condition of vacuum packaging, to obtain the vacuum degree in the cavity of the MEMS device.

Specifically, the quality factor under vacuum packaging conditions is input into the fitting equation representing the linear relationship between air pressure and quality factor for calculation, and the vacuum degree in the cavity of the MEMS device is obtained.

In the method for measuring the degree of vacuum of the above-mentioned MEMS device, the quality factor of the MEMS device under vacuum packaging conditions is obtained; the quality factor of the MEMS device under different air pressure conditions is obtained; the fitting equation is obtained according to the quality factor under different air pressure conditions; Based on the fitting equation and the quality factor under vacuum packaging conditions, the cavity vacuum degree of the MEMS device is obtained. The whole scheme measures the quality factor of the MEMS device under different air pressure conditions, and performs fitting according to the quality factor under different air pressure conditions to obtain a fitting equation. The fitting equation can accurately describe the correlation between air pressure and quality factor, and then according to The fitting equation and the quality factor under vacuum packaging conditions can be calculated to quickly and accurately obtain the vacuum degree in the cavity of the MEMS device.

In an optional embodiment, as shown in Figure 3, fitting is carried out according to the quality factor under different air pressure conditions, and the fitting equation obtained includes:

Step 620, obtaining the correlation between the quality factor and air pressure.

Wherein, the correlation includes a positive correlation and a negative correlation. Based on theoretical research and analysis, the correlation between the quality factor and air pressure is a negative correlation, that is, the quality factor is inversely proportional to the air pressure in the chamber.

The terminal acquires the correlation between the quality factor and the air pressure locally.

Step 640, based on the least square method and the correlation between the quality factor and the air pressure, perform linear fitting on the quality factor under different air pressure conditions to obtain a fitting equation.

Specifically, using the air pressure as the independent variable and the reciprocal of the quality factor as the dependent variable, based on the least squares method, the quality factors under different air pressure conditions were linearly fitted, and a fitting equation representing the linear relationship between air pressure and quality factor was obtained.

In an optional embodiment, obtaining the correlation between the quality factor and the air pressure includes: obtaining damping expressions of different types of damping; based on the damping expressions of different types of damping, determining the quality factor expressions under the influence of different types of damping ; According to the ideal gas state equation and the quality factor expression under the influence of different types of damping, determine the correlation between the quality factor and the air pressure.

Specifically, this embodiment is aimed at measuring the vacuum degree of the resonant MEMS device, and the vacuum degree measurement is mainly based on the relationship between the quality factor of the resonant MEMS device, the pressure in the cavity, and the number of gas molecules.

First, obtain the damping expressions of different types of damping; since the quality factor is related to damping, obtain the general quality factor expression, and then bring the damping expressions of different types of damping into the general damping expression to obtain the quality under the influence of different types of damping Factor expression; after that, obtain the ideal gas state equation and the air viscosity coefficient expression, the ideal gas state equation includes the air pressure parameter, and substitute the ideal gas state equation and the air viscosity coefficient expression into the quality factor expression under the influence of different types of damping, The correlation between quality factor and air pressure under the influence of different types of damping is obtained. When the correlation between quality factor and air pressure under the influence of different types of damping is consistent, the correlation between quality factor and air pressure is obtained.

In an optional embodiment, obtaining damping expressions of different types of damping includes: obtaining a compression film damping expression and a synovial film damping expression;

Based on the damping expressions of different types of damping, determining the expression of the quality factor under the influence of different types of damping includes: based on the expression of the compression film damping and the expression of the sliding film damping, determining the expression of the first quality factor under the influence of the compression film damping and the expression of the sliding film The second quality factor expression under the influence of membrane damping;

According to the ideal gas state equation and the expression of the quality factor under the influence of different types of damping, determining the correlation between the quality factor and the air pressure includes: according to the ideal gas state equation and the first quality factor expression, determining the relationship between the first quality factor and the air pressure The correlation between; according to the ideal gas state equation and the second quality factor expression, determine the correlation between the second quality factor and the air pressure; the correlation between the first quality factor and the air pressure and the second quality factor and the air pressure In the case of the same correlation relationship, the correlation relationship between quality factor and air pressure is obtained.

Among them, different types of damping include compression film damping and synovial film damping.

Specifically, the mathematical model for measuring the vacuum degree based on the relationship between the quality factor of the resonant MEMS device, the pressure in the cavity and the number of gas molecules is firstly introduced.

The micromechanical structure inside the MEMS device will be affected by air damping when vibrating. According to the direction of vibration, it can be divided into compression film damping and synovial film damping, as shown in Figure 4. Generally speaking, the movement of the structure will produce both compression film damping and sliding film damping, but for the resonator of MEMS devices, one of the damping is often dominant. In order to illustrate that the relationship between the quality factor and the air pressure in the cavity will not change due to different damping types, the following two types of damping will be analyzed.

The calculation formulas of compression film damping and synovial film damping (that is, the expression of compression film damping and the expression of synovial film damping) are as follows:

Among them, C _squeeze is the compression film damping; μ is the air viscosity coefficient; w is the width of the movable structure; l is the length of the movable structure; α is the shape coefficient of the movable structure, which depends on w/l; The gap between the moving structure and the fixed structure.

Among them, C _slide is the synovial film damping; A is the overlap area between the movable structure and the fixed structure.

The air viscosity coefficient μ can be expressed by the following formula:

where ρ is the air density, is the average rate, /> is the mean free path, k _b is the Boltzmann constant and k _b =1.3806×10 ^-23 J/K; T is the ambient temperature; N is the number of moles of gas molecules in the cavity;/> is the mean free time of gas molecules in the cavity; V is the volume of the space in the cavity;

Under the influence of two kinds of air damping, the quality factor (the first quality factor expression and the second quality factor expression) of the harmonic oscillator can be expressed as:

Among them, Q _d , Q _s are the quality factors under compression film damping and sliding film damping respectively; m is the mass of the movable mass, ω _d , ω _s are the resonant frequencies under compression film damping and sliding film damping respectively;

The equation of state of an ideal gas is shown in formula (7):

PV=Nk _b T(7)

Substituting formula (4) and formula (7) into formula (5) and formula (6) can get the relationship between quality factor and air pressure (the correlation between the first quality factor and air pressure and the correlation between the second quality factor and air pressure relationship):

Therefore, the relationship between the quality index of MEMS devices, the number of gas molecules, and the air pressure in the cavity is shown in formula (10). The correlation between the first quality factor and the air pressure is a negative correlation, and the relationship between the second quality factor and the air pressure The correlation between them is a negative correlation, therefore, the quality factor is inversely proportional to the air pressure in the cavity.

In an optional embodiment, obtaining the quality factor of the MEMS device under the vacuum packaging condition includes: acquiring the quality factor of the MEMS device under the vacuum packaging condition based on a frequency sweep method.

Specifically, when measuring the quality factor of MEMS devices under vacuum packaging conditions, the frequency sweep method can be used to connect the well-packaged MEMS devices to the frequency sweep circuit board, power the frequency sweep circuit board and conduct Electrical frequency sweep, according to the spectrum data to obtain the quality factor when the package is intact, to obtain the quality factor.

In an optional embodiment, obtaining the quality factor of the MEMS device under the vacuum packaging condition includes: acquiring the quality factor of the MEMS device under the vacuum packaging condition based on an oscillation attenuation method.

Specifically, the MEMS device testing system measures the quality factor of the MEMS device under vacuum packaging conditions based on the oscillation attenuation method, and sends the quality factor to the terminal, and the terminal obtains the quality factor of the MEMS device under vacuum packaging conditions measured by the MEMS device testing system .

In an optional embodiment, obtaining the quality factor of the MEMS device under different air pressure conditions includes: obtaining an air pressure set, based on the air pressure set, determining a preset air pressure sequence; placing the MEMS device in each air pressure environment in the preset air pressure sequence , the quality factor of the MEMS device under each air pressure environment condition is obtained.

Wherein, multiple air pressures with different sizes are stored in the air pressure set.

Specifically, the terminal acquires the air pressure set, sorts the air pressure in the air pressure set, obtains the preset air pressure sequence, generates measurement instructions according to the preset air pressure sequence, and sends the measurement instructions to the MEMS device testing system, and the MEMS device testing system according to the measurement instructions Get preset air pressure sequence. Then, adjust the air pressure of the vacuum pump according to the preset air pressure sequence, so as to control and adjust the air pressure of the vacuum chamber to reach each air pressure in the preset air pressure sequence, so as to obtain the quality factor of the MEMS device under each air pressure environment condition.

In order to easily understand the technical solution provided by the embodiment of the present application, the method for measuring the vacuum degree of the MEMS device provided by the embodiment of the present application is briefly described with the complete vacuum measurement process of the MEMS device:

1. Take the vacuum packaged MEMS device as the test sample;

2. Measure the quality factor Q ₀ when the resonant MEMS device package is intact by frequency sweep method or oscillation attenuation method;

3. Uncover the package of the MEMS device. After opening the cover, place the MEMS device in a vacuum device equipped with a vacuum pump. The device can control and adjust the air pressure of the vacuum chamber by adjusting the vacuum pump, and has external electrical connection wires for testing samples to be measured;

4. Adjust the air pressure P of the vacuum chamber, measure the quality factor of the MEMS device again, and record the air pressure P ₁ of the vacuum chamber and the quality factor Q ₁ of the MEMS device at this time;

5. Then adjust the air pressure P of the vacuum chamber, measure the quality factor of the MEMS device, and obtain a series of quality factors Q of the MEMS device corresponding to P;

6. With X=P as the abscissa and Y=1/Q as the ordinate, perform linear fitting to obtain a linear fitting equation;

7. According to the fitting equation and the quality factor Q ₀ when the packaging is intact, the vacuum degree in the cavity when the resonant MEMS device is packaged is obtained.

In an application embodiment, taking the MEMS device as a gyroscope as an example for measurement, the specific implementation process is as follows:

1. The sample to be tested is a vacuum-packaged MEMS gyroscope;

2. Connect the well-packaged MEMS gyroscope to the frequency-sweeping circuit board, power up the frequency-sweeping circuit board and perform electrical frequency-sweeping on the sensitive structure of the MEMS gyroscope, and obtain the quality factor Q ₀ =16719 when the package is intact according to the spectrum data;

3. Open the package of the MEMS gyroscope to expose its sensitive structure;

4. Place the MEMS device after opening the cover in the vacuum device, which is connected with a vacuum pump to facilitate the adjustment of the air pressure in the vacuum chamber, and the vacuum device has an electrical connection interface with the outside world;

5. Adjust the air pressure P of the vacuum device to make it 1000Pa. Through the above electrical interface, use the frequency sweep circuit board to measure the quality factor of the sensitive structure of the MEMS device gyroscope at this time after opening the cover, and record it as Q ₁ ;

6. Adjust Q again so that it is 800Pa, 600Pa, 400Pa, 200Pa, 100Pa, 10Pa in turn, measure the quality factors under different air pressures, and record them as Q ₂ , Q ₃ , Q ₄ , Q ₅ , Q ₆ , _Q7 ;

7. According to the data in step 6, calculate X=P, Y=1/Q, record and table, see Table 1.

Table 1 Quality factor under different air pressure

8. With X as the abscissa and Y as the ordinate, use the least squares method for linear fitting, as shown in Figure 6, it can be seen that the linear correlation between the two is 0.9925, and there is a linear relationship;

9. Linear fitting The linear fitting equation Y=1.9143×10 ^–5 +7.4142×10 ^–7 ×X can be obtained, and it can be calculated that the vacuum degree in the sealed cavity is 54Pa when the MEMS gyroscope is well packaged.

The present application solves the problem that in the current method, the vacuum measuring elements need to be packaged together into the sealed cavity, thereby occupying the narrow space of the sealed cavity. Since the method for measuring the vacuum degree of the MEMS device provided in the present application uses linear fitting to calculate the air pressure in the packaging cavity of the vacuum-packaged MEMS device, the vacuum degree in the packaging cavity of the vacuum-packaged MEMS device can be reliably obtained. The MEMS device vacuum measurement method provided in the present application can also be used to measure the distribution of the vacuum degree in the cavity of the same batch of MEMS devices, and verify the quality consistency of the vacuum packaging process. In addition, the method is helpful to help packaging technicians adjust the packaging air pressure and evaluate the vacuum packaging process level. Therefore, the method is helpful to develop vacuum-packaged MEMS devices with good quality consistency and high reliability.

It should be understood that although the steps in the flow charts involved in the above embodiments are shown sequentially according to the arrows, these steps are not necessarily executed sequentially in the order indicated by the arrows. Unless otherwise specified herein, there is no strict order restriction on the execution of these steps, and these steps can be executed in other orders. Moreover, at least some of the steps in the flow charts involved in the above embodiments may include multiple steps or stages, and these steps or stages are not necessarily executed at the same time, but may be executed at different times, The execution order of these steps or stages is not necessarily performed sequentially, but may be executed in turn or alternately with other steps or at least a part of steps or stages in other steps.

Based on the same inventive concept, an embodiment of the present application also provides a MEMS device vacuum degree measuring device for implementing the above-mentioned method for measuring the vacuum degree of a MEMS device. The solution to the problem provided by the device is similar to the implementation described in the above method, so the specific limitations in one or more embodiments of the MEMS device vacuum measurement device provided below can be referred to above for the MEMS device vacuum The limitation of the degree measurement method will not be repeated here.

In one embodiment, as shown in Figure 7, a MEMS device vacuum measurement device is provided, including: a first acquisition module 702, a second acquisition module 704, a fitting module 706 and a calculation module 708, wherein:

The first obtaining module 702 is used to obtain the quality factor of the MEMS device under vacuum packaging conditions;

The second obtaining module 704 is used to obtain the quality factor of the MEMS device under different air pressure conditions;

Fitting module 706, is used for fitting according to the quality factor under different air pressure conditions, obtains fitting equation;

The calculation module 708 is configured to perform calculation based on the fitting equation and the quality factor under vacuum packaging conditions to obtain the vacuum degree in the cavity of the MEMS device.

In one of the embodiments, the fitting module 706 is also used to obtain the correlation between the quality factor and the air pressure, and the correlation includes a positive correlation and a negative correlation; based on the least square method and the correlation between the quality factor and the air pressure , and perform linear fitting on the quality factor under different air pressure conditions to obtain the fitting equation.

In one of the embodiments, the fitting module 706 is also used to obtain damping expressions of different types of damping; based on the damping expressions of different types of damping, determine the quality factor expression under the influence of different types of damping; according to the ideal gas state equation and Expressions for the quality factor under the influence of different types of damping to determine the correlation between the quality factor and air pressure.

In one of the embodiments, the fitting module 706 is also used to obtain the compression film damping expression and the synovial film damping expression; based on the compression film damping expression and the synovial film damping expression, determine the first quality under the influence of the compression film damping The factor expression and the second quality factor expression under the influence of synovial damping; according to the ideal gas state equation and the first quality factor expression, determine the correlation between the first quality factor and the air pressure; according to the ideal gas state equation and the first quality factor expression The second quality factor expression determines the correlation between the second quality factor and the air pressure; when the correlation between the first quality factor and the air pressure is the same as the correlation between the second quality factor and the air pressure, the quality Correlation between factor and air pressure.

In one of the embodiments, the first obtaining module 702 is also used to obtain the quality factor of the MEMS device under the condition of vacuum packaging based on the frequency sweep method.

In one of the embodiments, the first obtaining module 702 is also used to obtain the quality factor of the MEMS device under the condition of vacuum packaging based on the oscillation attenuation method.

In one of the embodiments, the second obtaining module 704 is also used to obtain the air pressure set, and determine the preset air pressure sequence based on the air pressure set; place the MEMS device in each air pressure environment in the preset air pressure sequence, and obtain the MEMS device in each air pressure environment. The figure of merit at atmospheric pressure.

Each module in the above-mentioned MEMS device vacuum degree measuring device can be fully or partially realized by software, hardware and a combination thereof. The above-mentioned modules can be embedded in or independent of the processor in the computer device in the form of hardware, and can also be stored in the memory of the computer device in the form of software, so that the processor can invoke and execute the corresponding operations of the above-mentioned modules.

In one embodiment, a computer device is provided. The computer device may be a terminal, and its internal structure may be as shown in FIG. 8 . The computer device includes a processor, a memory, a communication interface, a display screen and an input device connected through a system bus. Wherein, the processor of the computer device is used to provide calculation and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system and computer programs. The internal memory provides an environment for the operation of the operating system and computer programs in the non-volatile storage medium. The communication interface of the computer device is used to communicate with an external terminal in a wired or wireless manner, and the wireless manner can be realized through WIFI, mobile cellular network, NFC (near field communication) or other technologies. When the computer program is executed by the processor, a method for measuring the vacuum degree of the MEMS device is realized. The display screen of the computer device may be a liquid crystal display screen or an electronic ink display screen, and the input device of the computer device may be a touch layer covered on the display screen, or a button, a trackball or a touch pad provided on the casing of the computer device , and can also be an external keyboard, touchpad or mouse.

Those skilled in the art can understand that the structure shown in FIG. 8 is only a block diagram of a partial structure related to the solution of this application, and does not constitute a limitation on the computer equipment to which the solution of this application is applied. The specific computer equipment can be More or fewer components than shown in the figures may be included, or some components may be combined, or have a different arrangement of components.

In one embodiment, a computer device is provided, including a memory and a processor, a computer program is stored in the memory, and the processor implements the following steps when executing the computer program:

Obtain the quality factor of MEMS devices under vacuum packaging conditions;

Obtain the quality factor of MEMS devices under different air pressure conditions;

Fitting is carried out according to the quality factors under different air pressure conditions, and the fitting equation is obtained;

Based on the fitting equation and the quality factor under vacuum packaging conditions, the cavity vacuum degree of the MEMS device is obtained.

In one embodiment, when the processor executes the computer program, the following steps are also implemented: performing fitting according to the quality factor under different air pressure conditions, and obtaining the fitting equation includes: obtaining the correlation between the quality factor and the air pressure, and the correlation includes a positive Correlation and negative correlation; based on the least square method and the correlation between quality factor and air pressure, the quality factor under different air pressure conditions is linearly fitted to obtain the fitting equation.

In one embodiment, when the processor executes the computer program, the following steps are also implemented: obtaining damping expressions of different types of damping; determining the quality factor expressions under the influence of different types of damping based on the damping expressions of different types of damping; The equation of state and the expression of the quality factor under the influence of different types of damping determine the correlation between the quality factor and the air pressure.

In one embodiment, when the processor executes the computer program, the following steps are also implemented: obtaining the compression film damping expression and the synovial film damping expression; based on the compression film damping expression and the synovial film damping expression, determining the The first quality factor expression and the second quality factor expression under the influence of synovial film damping; according to the ideal gas state equation and the first quality factor expression, determine the correlation between the first quality factor and the air pressure; according to the ideal gas state equation and a second figure of merit expression to determine the correlation between the second figure of merit and air pressure; where the correlation between the first figure of merit and air pressure is the same as the correlation between the second figure of merit and air pressure , to get the correlation between quality factor and air pressure.

In one embodiment, when the processor executes the computer program, the following steps are further implemented: based on the frequency sweep method, the quality factor of the MEMS device under the condition of vacuum packaging is obtained.

In one embodiment, when the processor executes the computer program, the following steps are further implemented: based on the oscillation attenuation method, the quality factor of the MEMS device under the condition of vacuum packaging is obtained.

In one embodiment, when the processor executes the computer program, the following steps are also implemented: obtaining the set of air pressure, determining the preset air pressure sequence based on the set of air pressure; placing the MEMS device under each air pressure environment in the preset air pressure sequence, and obtaining the MEMS device The figure of merit at each atmospheric pressure ambient condition.

In one embodiment, a computer-readable storage medium is provided, on which a computer program is stored, and when the computer program is executed by a processor, the following steps are implemented:

Obtain the quality factor of MEMS devices under vacuum packaging conditions;

Obtain the quality factor of MEMS devices under different air pressure conditions;

Fitting is carried out according to the quality factors under different air pressure conditions, and the fitting equation is obtained;

Based on the fitting equation and the quality factor under vacuum packaging conditions, the cavity vacuum degree of the MEMS device is obtained.

In one embodiment, when the computer program is executed by the processor, the following steps are also implemented: performing fitting according to the quality factors under different air pressure conditions, and obtaining the fitting equation includes: obtaining the correlation between the quality factor and the air pressure, and the correlation includes Positive correlation and negative correlation; based on the least square method and the correlation between quality factor and air pressure, the quality factor under different air pressure conditions is linearly fitted to obtain the fitting equation.

In one embodiment, when the computer program is executed by the processor, the following steps are also implemented: obtaining damping expressions of different types of damping; based on the damping expressions of different types of damping, determining the quality factor expression under the influence of different types of damping; according to the ideal The gas state equation and the expression of the quality factor under the influence of different types of damping determine the correlation between the quality factor and the air pressure.

In one embodiment, when the computer program is executed by the processor, the following steps are also implemented: obtaining the expression of the compression film damping and the expression of the synovial film damping; based on the expression of the compression film damping and the expression of the synovial film damping, determining The first quality factor expression and the second quality factor expression under the influence of synovial film damping; according to the ideal gas state equation and the first quality factor expression, determine the correlation between the first quality factor and the air pressure; according to the ideal gas The state equation and the second quality factor expression determine the correlation between the second quality factor and the air pressure; the correlation between the first quality factor and the air pressure is the same as the correlation between the second quality factor and the air pressure Next, the correlation between quality factor and air pressure is obtained.

In one embodiment, when the computer program is executed by the processor, the following steps are further implemented: based on the frequency sweep method, the quality factor of the MEMS device under the condition of vacuum packaging is obtained.

In one embodiment, when the computer program is executed by the processor, the following steps are further implemented: based on the oscillation attenuation method, the quality factor of the MEMS device under the condition of vacuum packaging is obtained.

In one embodiment, when the computer program is executed by the processor, the following steps are also implemented: obtaining the set of air pressure, and determining the preset air pressure sequence based on the set of air pressure; placing the MEMS device in each air pressure environment in the preset air pressure sequence, and obtaining the MEMS The figure of merit of the device at each atmospheric pressure ambient condition.

In one embodiment, a computer program product is provided, comprising a computer program, which, when executed by a processor, implements the following steps:

Obtain the quality factor of MEMS devices under vacuum packaging conditions;

Obtain the quality factor of MEMS devices under different air pressure conditions;

Fitting is carried out according to the quality factors under different air pressure conditions, and the fitting equation is obtained;

Based on the fitting equation and the quality factor under vacuum packaging conditions, the cavity vacuum degree of the MEMS device is obtained.

In one embodiment, when the computer program is executed by the processor, the following steps are also implemented: performing fitting according to the quality factors under different air pressure conditions, and obtaining the fitting equation includes: obtaining the correlation between the quality factor and the air pressure, and the correlation includes Positive correlation and negative correlation; based on the least square method and the correlation between quality factor and air pressure, the quality factor under different air pressure conditions is linearly fitted to obtain the fitting equation.

In one embodiment, when the computer program is executed by the processor, the following steps are also implemented: obtaining damping expressions of different types of damping; based on the damping expressions of different types of damping, determining the quality factor expression under the influence of different types of damping; according to the ideal The gas state equation and the expression of the quality factor under the influence of different types of damping determine the correlation between the quality factor and the air pressure.

In one embodiment, when the computer program is executed by the processor, the following steps are also implemented: obtaining the expression of the compression film damping and the expression of the synovial film damping; based on the expression of the compression film damping and the expression of the synovial film damping, determining The first quality factor expression and the second quality factor expression under the influence of synovial film damping; according to the ideal gas state equation and the first quality factor expression, determine the correlation between the first quality factor and the air pressure; according to the ideal gas The state equation and the second quality factor expression determine the correlation between the second quality factor and the air pressure; the correlation between the first quality factor and the air pressure is the same as the correlation between the second quality factor and the air pressure Next, the correlation between quality factor and air pressure is obtained.

In one embodiment, when the computer program is executed by the processor, the following steps are further implemented: based on the frequency sweep method, the quality factor of the MEMS device under the condition of vacuum packaging is obtained.

In one embodiment, when the computer program is executed by the processor, the following steps are further implemented: based on the oscillation attenuation method, the quality factor of the MEMS device under the condition of vacuum packaging is obtained.

In one embodiment, when the computer program is executed by the processor, the following steps are also implemented: obtaining the set of air pressure, and determining the preset air pressure sequence based on the set of air pressure; placing the MEMS device in each air pressure environment in the preset air pressure sequence, and obtaining the MEMS The figure of merit of the device at each atmospheric pressure ambient condition.

Those of ordinary skill in the art can understand that realizing all or part of the processes in the methods of the above embodiments can be completed by instructing related hardware through computer programs, and the computer programs can be stored in a non-volatile computer-readable storage medium , when the computer program is executed, it may include the procedures of the embodiments of the above-mentioned methods. Wherein, any reference to storage, database or other media used in the various embodiments provided in the present application may include at least one of non-volatile and volatile storage. Non-volatile memory can include read-only memory (Read-Only Memory, ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive variable memory (ReRAM), magnetic variable memory (Magnetoresistive Random Access Memory, MRAM), Ferroelectric Random Access Memory (FRAM), Phase Change Memory (Phase Change Memory, PCM), graphene memory, etc. The volatile memory may include random access memory (Random Access Memory, RAM) or external cache memory. As an illustration and not a limitation, RAM can be in various forms, such as Static Random Access Memory (SRAM) or Dynamic Random Access Memory (Dynamic Random Access Memory, DRAM). The databases involved in the various embodiments provided in this application may include at least one of a relational database and a non-relational database. The non-relational database may include a blockchain-based distributed database, etc., but is not limited thereto. The processors involved in the various embodiments provided by this application can be general-purpose processors, central processing units, graphics processors, digital signal processors, programmable logic devices, data processing logic devices based on quantum computing, etc., and are not limited to this.

The technical features of the above embodiments can be combined arbitrarily. For the sake of concise description, all possible combinations of the technical features in the above embodiments are not described. However, as long as there is no contradiction in the combination of these technical features, they should be It is considered to be within the range described in this specification.

The above examples only express several implementation modes of the present application, and the description thereof is relatively specific and detailed, but should not be construed as limiting the patent scope of the present application. It should be noted that those skilled in the art can make several modifications and improvements without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the present application should be determined by the appended claims.

Claims (10)

1. A method for measuring vacuum degree of a MEMS device, the method comprising:

acquiring a quality factor of the MEMS device under the vacuum packaging condition;

acquiring quality factors of the MEMS device under different air pressure conditions;

fitting according to the quality factors under the different air pressure conditions to obtain a fitting equation;

and calculating based on the fitting equation and the quality factor under the vacuum packaging condition to obtain the intracavity vacuum degree of the MEMS device.

2. The method of claim 1, wherein said fitting based on figures of merit for said different barometric conditions comprises:

acquiring a correlation between a quality factor and air pressure, wherein the correlation comprises a positive correlation and a negative correlation;

and carrying out linear fitting on the quality factors under different air pressure conditions based on a least square method and the correlation between the quality factors and the air pressure to obtain a fitting equation.

3. The method of claim 2, wherein the obtaining a correlation between the figure of merit and the barometric pressure comprises:

acquiring damping expressions of different types of damping;

determining a quality factor expression under the influence of different types of damping based on the damping expressions of different types of damping;

and determining the correlation between the quality factor and the air pressure according to an ideal air state equation and the quality factor expression under the influence of the different types of damping.

4. The method of claim 3, wherein the step of,

the obtaining damping expressions of different types of damping includes:

obtaining a squeeze film damping expression and a slide film damping expression;

The determining the quality factor expression under the influence of different types of damping based on the damping expressions of different types of damping comprises:

determining a first quality factor expression under the influence of film pressing damping and a second quality factor expression under the influence of film sliding damping based on the film pressing damping expression and the film sliding damping expression;

the determining the correlation between the quality factor and the air pressure according to the ideal air state equation and the quality factor expression under the different damping effects comprises:

determining a correlation between a first figure of merit and gas pressure according to an ideal gas state equation and the first figure of merit expression;

determining a correlation between a second figure of merit and gas pressure according to an ideal gas state equation and the second figure of merit expression;

and obtaining the correlation between the quality factor and the air pressure under the condition that the correlation between the first quality factor and the air pressure is the same as the correlation between the second quality factor and the air pressure.

5. The method of claim 1, wherein the obtaining a quality factor of the MEMS device under vacuum packaging conditions comprises:

Based on a sweep frequency method, the quality factor of the MEMS device under the vacuum packaging condition is obtained.

6. The method of claim 1, wherein the obtaining a quality factor of the MEMS device under vacuum packaging conditions comprises:

based on an oscillation attenuation method, the quality factor of the MEMS device under the vacuum packaging condition is obtained.

7. The method of claim 1, wherein the obtaining the figures of merit for the MEMS device under different barometric conditions comprises:

acquiring an air pressure set, and determining a preset air pressure sequence based on the air pressure set;

and placing the MEMS device in each air pressure environment in the preset air pressure sequence, and obtaining the quality factor of the MEMS device under each air pressure environment condition.

8. A MEMS device vacuum measurement apparatus, the apparatus comprising:

the first acquisition module is used for acquiring the quality factor of the MEMS device under the vacuum packaging condition;

the second acquisition module is used for acquiring the quality factors of the MEMS device under different air pressure conditions;

the fitting module is used for fitting according to the quality factors under the different air pressure conditions to obtain a fitting equation;

and the calculation module is used for calculating based on the fitting equation and the quality factor under the vacuum packaging condition to obtain the intracavity vacuum degree of the MEMS device.

9. A computer device comprising a memory and a processor, the memory storing a computer program, characterized in that the processor implements the steps of the method of any of claims 1 to 7 when the computer program is executed.

10. A computer readable storage medium, on which a computer program is stored, characterized in that the computer program, when being executed by a processor, implements the steps of the method of any of claims 1 to 7.