A reliability detection method for a MEMS flow sensor

Abstract

The application discloses a reliability detection method of a MEMS flow sensor, and comprises the following steps: performing an acceleration test of an aging test of the sensor under voltage and temperature stress conditions; extracting an acceleration test aging model; calculating life data under the stress test conditions according to a characteristic parameter and a mathematical model by using an Arrhenius model; establishing a finite element simulation model by using 3D modeling software, and performing voltage and temperature stress simulation on the finite element simulation model according to actual requirements of use conditions and acceleration test conditions; performing fatigue simulation, and importing stress-life data obtained under actual experimental conditions into the fatigue simulation model to finally obtain a stress-life curve of the sensor; and testing the reliability of the finite element simulation model. The method disclosed by the application can realize evaluation and calculation of the reliability of the MEMS flow sensor under various practical stresses while shortening test time and reducing test cost.

Description

Technical Field

[0001] This invention relates to the field of MEMS flow sensor technology, and in particular to a method for reliability testing of MEMS flow sensors. Background Technology

[0002] With the rise of MEMS technology in the 1990s, various types of thermal flow sensors have been fabricated using MEMS technology. These sensors feature high measurement accuracy, low power consumption, and good detection performance, leading to significant development in MEMS-based sensors. However, due to the complexity of their operating environment and the involvement of various fields such as physics and chemistry in their working principles, reliability assessment is playing an increasingly important role in the development of MEMS design and applications.

[0003] Traditional reliability assessment methods primarily rely on life testing. Life testing involves randomly selecting a certain sample size of products as test specimens, tracking their usage, and recording data such as failure time (lifespan) and causes of failure. After obtaining the lifespan data, statistical inference methods are used to perform statistical analysis on this data, obtaining estimates of the product's lifespan and reliability indicators. This verifies whether the product's reliability indicators meet the specified requirements, thereby achieving the goal of lifespan and reliability assessment. In short, life testing refers to the general term for various tests conducted to analyze, evaluate, and improve the lifespan and reliability levels of products. While life testing can assess the lifespan and reliability levels of products or systems, for high-reliability, long-life products, life testing under normal environmental or operational stress levels is often too time-consuming, expensive, and inefficient, failing to achieve the goal of rapidly assessing the lifespan and reliability levels of high-reliability, long-life products under specified conditions.

[0004] Therefore, in order to shorten testing time, reduce testing costs, and improve testing efficiency, and to rapidly assess the lifespan and reliability levels of high-reliability, long-life products such as MEMS sensors within a short period of time, it is necessary to research new and more effective testing methods and technologies. Accelerated life testing emerged and developed in this context. The introduction of accelerated life testing technology provides a new approach to quickly, rationally, and effectively solving the problem of lifespan and reliability assessment of high-reliability, long-life products under specified conditions. Its emergence is of milestone significance in the field of reliability engineering. Accelerated testing is a life testing method that accelerates the failure of a product under high stress levels while keeping the failure mechanism unchanged. Its purpose is to quickly obtain test data, rapidly identify the cause of failure, and use accelerated models to statistically infer various reliability indicators of the product under normal stress levels. However, existing accelerated testing mainly relies on experiments and lacks the integration of fatigue simulation. It uses a single accelerated stress to obtain device fatigue or lifespan data, and there is no good assessment of the threshold range of each accelerated stress. In order to obtain accelerated test results within a limited time, one or two accelerated stresses are often selected. Therefore, it cannot comprehensively reflect the fatigue or lifespan of the device under different types and stress values ​​during accelerated testing. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention provides a reliability testing method for MEMS flow sensors, aiming to evaluate and calculate the reliability of MEMS flow sensors under various practical stresses while shortening testing time and reducing testing costs.

[0006] To achieve the above objectives, the technical solution of the present invention is as follows:

[0007] A reliability testing method for a MEMS flow sensor includes the following steps:

[0008] Step 1: Conduct accelerated aging tests on the MEMS flow sensor under voltage and temperature stress conditions. Analyze the performance drift or degradation of the MEMS flow sensor based on the experimental results and select characteristic parameters.

[0009] Step 2: By calculating the experimental results, an accelerated aging test model suitable for the MEMS flow sensor is extracted, namely, a mathematical model of stress and life under accelerated aging conditions of voltage and temperature stress; and the life data under the above stress test conditions is calculated using the Arrhenius model based on the characteristic parameters and the mathematical model.

[0010] Step 3: Use 3D modeling software to establish a finite element simulation model based on the actual size of the MEMS flow sensor. Based on the actual needs of the operating conditions and accelerated testing conditions, perform voltage and temperature stress simulation on the finite element simulation model.

[0011] Step 4: Based on the above simulation results and accelerated testing, fatigue simulation of the MEMS flow sensor is performed using ANSYS nCode DesignLife. The stress-life data obtained under actual experimental conditions is imported into the fatigue simulation model to finally obtain the stress-life curve of the MEMS flow sensor.

[0012] Step 5: Compare the life data obtained from the simulation with the life data calculated from the characteristic parameters in the experiment to verify the reliability of the finite element simulation model.

[0013] In the above scheme, the specific method for accelerated testing in step one is as follows:

[0014] Accelerated stress tests were designed based on voltage and temperature, with a voltage range of 1V-5V and a temperature range of 85℃-180℃. The following experimental groups were designed: constant voltage accelerated stress test group (1V, 3V, 5V); voltage step-stress accelerated test group (1V-3V-5V); constant temperature accelerated stress test group (85℃, 120℃, 150℃, 180℃); temperature step-stress accelerated test group (85℃-120℃-150℃-180℃); and temperature + voltage dual-stress accelerated test to collect experimental data.

[0015] In the above scheme, in step three, SolidWorks is used as the 3D modeling software to recreate the actual accelerated test conditions.

[0016] In the above scheme, in step three, the method for simulating voltage and temperature stress using the finite element simulation model is as follows: starting from the constituent materials of the MEMS flow sensor, the heat transfer at the contact surfaces of different materials and the heat transfer within the same material are analyzed to obtain the specific parameters of thermal stress and thermal deformation displacement caused by thermal expansion under various stress conditions.

[0017] Through the above technical solution, the reliability detection method for a MEMS flow sensor provided by the present invention has the following beneficial effects:

[0018] The method of this invention accelerates the failure of MEMS flow sensor products under high stress levels, enabling rapid acquisition of test data. Secondly, by combining experimental results with degradation and drift mechanisms, finite element simulation and fatigue simulation are established. Ultimately, this shortens reliability testing time, reduces testing costs, and improves testing efficiency, yielding the performance parameters, lifespan, and reliability of the MEMS flow sensor under various operating stresses. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below.

[0020] Figure 1 This is a schematic diagram of a reliability testing method for a MEMS flow sensor disclosed in an embodiment of the present invention. Detailed Implementation

[0021] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention.

[0022] This invention provides a reliability testing method for a MEMS flow sensor. In this embodiment, the MEMS flow sensor used includes a flow sensor chip, a signal processing circuit (PCB), and an external tooling fixture.

[0023] like Figure 1 As shown, the reliability testing method includes the following steps:

[0024] Step 1: Conduct accelerated aging tests on the MEMS flow sensor under voltage and temperature stress conditions. Analyze the performance drift or degradation of the MEMS flow sensor based on the experimental results and select characteristic parameters.

[0025] The specific methods for accelerated testing are as follows:

[0026] Accelerated testing was conducted using a constant temperature and humidity aging chamber, and data was acquired using an NI data acquisition card. Accelerated stresses, including voltage and temperature, were designed with a voltage range of 1V-5V and a temperature range of 85℃-180℃. The following experimental groups were designed: constant voltage accelerated testing at 1V, 3V, and 5V; stepped voltage accelerated testing at 1V-3V-5V; constant temperature accelerated testing at 85℃, 120℃, 150℃, and 180℃; stepped temperature accelerated testing at 85℃-120℃-150℃-180℃; and a dual-stress accelerated testing (temperature + voltage) to collect experimental data. The selected characteristic parameter was the output voltage.

[0027] Step 2: By calculating the experimental results, an accelerated aging test model suitable for the MEMS flow sensor is extracted, namely, a mathematical model of stress and life under accelerated aging conditions of voltage and temperature stress; and the life data under the above stress test conditions is calculated using the Arrhenius model based on the characteristic parameters and the mathematical model.

[0028] Step 3: Using the 3D modeling software SolidWorks, a finite element simulation model is established based on the actual dimensions of the MEMS flow sensor. According to the actual requirements of the operating conditions and accelerated testing conditions, voltage and temperature stress simulations are performed on the finite element simulation model to ensure that the operating conditions of the device in the simulation model are consistent with the actual operating conditions, so as to further carry out fatigue life simulation of the device.

[0029] The specific method of stress simulation is as follows: Starting from the constituent materials of MEMS flow sensors, the heat transfer at the contact surfaces of different materials and the heat transfer within the same material are analyzed to obtain the specific parameters of thermal stress and thermal deformation displacement caused by thermal expansion under various stress conditions.

[0030] Step four: Based on the above simulation results and accelerated testing, fatigue simulation of the MEMS flow sensor is performed using ANSYS nCode DesignLife. The stress-life data obtained under actual experimental conditions is imported into the fatigue simulation model to finally obtain the stress-life curve of the MEMS flow sensor. This method is more instructive and practical, providing a new guidance scheme for device fatigue simulation and ensuring the reliability and authenticity of fatigue simulation.

[0031] Step five involves comparing the simulated lifetime data with the lifetime data calculated from the characteristic parameters in the experiment to verify the reliability of the finite element simulation model. This method compares the results of accelerated experiments with the results of fatigue simulations, using experiments to calibrate the simulation accuracy and simulations to predict the threshold range of various stresses that the device can withstand. This guides the experimental design steps and provides an advantageous closed-loop design scheme for MEMS reliability testing technology.

[0032] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A reliability testing method for a MEMS flow sensor, characterized in that, Includes the following steps: Step 1: Conduct accelerated aging tests on the MEMS flow sensor under voltage and temperature stress conditions. Analyze the performance drift or degradation of the MEMS flow sensor based on the experimental results and select characteristic parameters. Step 2: By calculating the experimental results, an accelerated aging test model suitable for the MEMS flow sensor is extracted, namely, a mathematical model of stress and life under accelerated aging conditions of voltage and temperature stress; and the life data under stress test conditions is calculated using the Arrhenius model based on the characteristic parameters and the mathematical model. Step 3: Use 3D modeling software to establish a finite element simulation model based on the actual size of the MEMS flow sensor. Based on the actual needs of the operating conditions and accelerated testing conditions, perform voltage and temperature stress simulation on the finite element simulation model. Step 4: Based on the simulation results and accelerated testing, fatigue simulation of the MEMS flow sensor is performed using ANSYS nCode DesignLife. The stress-life data obtained under actual experimental conditions is imported into the fatigue simulation model to finally obtain the stress-life curve of the MEMS flow sensor. Step 5: Compare the simulation-obtained lifetime data with the lifetime data calculated from the characteristic parameters in the experiment to verify the reliability of the finite element simulation model. In step three, the method for simulating voltage and temperature stress using the finite element simulation model is as follows: starting from the constituent materials of the MEMS flow sensor, the heat transfer at the contact surfaces of different materials and the heat transfer within the same material are analyzed to obtain the specific parameters of thermal stress and thermal deformation displacement caused by thermal expansion under various stress conditions.

2. The reliability testing method for a MEMS flow sensor according to claim 1, characterized in that, In step one, the specific method for accelerated testing is as follows: Accelerated stress tests were designed based on voltage and temperature, with a voltage range of 1V-5V and a temperature range of 85℃-180℃. The following experimental groups were designed: constant stress accelerated test group at 1V, 3V, and 5V; stepped stress accelerated test group at 1V-3V-5V; constant stress accelerated test group at 85℃, 120℃, 150℃, and 180℃; stepped stress accelerated test group at 85℃-120℃-150℃-180℃; and dual stress accelerated test group at both temperature and voltage. Experimental data were collected using these methods.

3. The reliability testing method for a MEMS flow sensor according to claim 1, characterized in that, In step three, SolidWorks was used as the 3D modeling software to recreate the actual accelerated test conditions.

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