Acceleration factor determination method for electronic device of nanometer time grating displacement sensor

Abstract

The invention discloses a method for determining an acceleration factor of an electronic device of a nanometer time grating displacement sensor, and the method comprises the steps: taking the electronic device with the lowest working nominal temperature as a research object, determining an acceleration test temperature range, and then measuring the repeatability of the nanometer time grating displacement sensor under different acceleration stress levels. The minimum acceleration stress level is determined through a standard deviation minimization principle; an acceleration factor under the minimum acceleration stress level is calculated through an Arrhenius model, and the acceleration factor of an electronic device of the nanometer time grating displacement sensor is comprehensively determined through the principle of taking the minimum acceleration factor. And finally, the reliability life of the electronic device of the nano time grating displacement sensor can be obtained through extrapolation of the acceleration factor without long-time test under natural conditions to verify the reliability life of the electronic device, so that the problems that the natural storage test period of the electronic device of the nano time grating displacement sensor is too long and the test time is short are effectively solved. And product research and development iteration requirements cannot be matched.

Description

Technical Field

[0001] The present invention relates to the technical field of life analysis of nano-time-grating displacement sensors, and in particular to a method for determining an acceleration factor of an electronic device of a nano-time-grating displacement sensor. Background Art

[0002] Nano-time-grating displacement sensors, the core device of a new generation of displacement measurement technology, include both nano-linear and nano-circular time-grating sensors. Their core advantage lies in overcoming the environmental adaptability bottlenecks of traditional optical measurement (such as laser interferometers) by enabling ultra-precision displacement detection through a nanoscale grating pitch-based space-time conversion mechanism. In high-tech fields such as high-end equipment manufacturing, semiconductor precision machining, and aerospace, the electronic components of nano-time-grating displacement sensors must meet stringent standards for long life and high reliability. The lifespan of their electronic systems directly determines the equipment's maintenance cycle and overall lifecycle cost.

[0003] In the process of productization of nano-time-grating displacement sensors, the reliability life verification of electronic devices is a key link. However, the design life of the electronic devices of nano-time-grating displacement sensors is usually tens of thousands of hours. Traditional natural aging tests are too time-consuming and difficult to match the iterative requirements of the product development cycle. Therefore, it is urgent to design an accelerated test method for electronic devices. By applying stress conditions, the failure process of the device is accelerated, the acceleration factor of the electronic device is extracted, and the acceleration factor is extrapolated to the life prediction model under normal working conditions, thereby significantly shortening the life verification cycle and improving R&D efficiency. However, the existing technology has not yet formed a systematic study on the method of determining the acceleration factor of the electronic devices of nano-time-grating displacement sensors, and the relevant theories and methods are in urgent need of breakthroughs. Summary of the Invention

[0004] In view of the above-mentioned deficiencies in the prior art, the purpose of the present invention is to provide a method for determining the acceleration factor of the electronic device of the nano-time-grating displacement sensor, so as to solve the problem that the natural storage test cycle of the electronic device of the nano-time-grating displacement sensor is too long and cannot meet the iterative requirements of product research and development.

[0005] In order to solve the above technical problems, the technical solution adopted by the present invention is as follows:

[0006] A method for determining an acceleration factor of an electronic device of a nanometer time-grating displacement sensor comprises the following steps:

[0007] (1) Determine the nominal operating temperature of each electronic component of the nanometer time-gate displacement sensor, and then determine the ambient temperature range of the accelerated test based on the lowest nominal operating temperature; assuming that the lowest nominal operating temperature is x°C, the ambient temperature range is x-25 to x°C;

[0008] (2) measuring the repeatability of the nano-time-grating displacement sensor under different acceleration stress levels, and using the standard deviation to represent the repeatability, taking the acceleration stress level corresponding to the minimum standard deviation as the minimum acceleration stress level; the acceleration stress level is composed of two variables: the input voltage and the ambient temperature of the acceleration test; the input voltage is any value in the rated input voltage of the nano-time-grating displacement sensor, and the ambient temperature is any value within the ambient temperature range described in step (1);

[0009] (3) Using the Arrhenius model to calculate the corresponding acceleration factor at the minimum acceleration stress level, the acceleration factor at the minimum acceleration stress level is taken as the acceleration factor of the electronic device of the nano-time grating displacement sensor;

[0010] The Arrhenius model is as follows:

[0011]

[0012] Where AF is the acceleration factor, Ea is the activation energy corresponding to the electronic device with the lowest nominal operating temperature, k is the Boltzmann constant, T1 is the ambient temperature corresponding to the minimum acceleration stress level, and T2 is room temperature.

[0013] Furthermore, the value range of Ea is -0.2 to 1.4 eV.

[0014] Furthermore, in step (2), the input voltage is the maximum value, minimum value or intermediate value of the rated input voltage, and the ambient temperature is several temperature points with a temperature interval of 5°C or 10°C. The input voltage and the ambient temperature are cross-matched to obtain different acceleration stress levels.

[0015] Furthermore, the repeatability is measured by the following method:

[0016] ① Under the same acceleration stress level, the moving ruler of the nano-time grating displacement sensor moves at a constant speed along the set path until it reaches the end point of the set path, then returns to the original path at the same speed and moves back and forth several times; during the movement, the displacement data of the moving ruler moving to the set time point is continuously collected. After the collection is completed, the standard deviation of the displacement data corresponding to the set time points during the process of the moving ruler moving from the starting point to the end point of the set path is calculated, and the minimum standard deviation is taken as the repeatability of the nano-time grating displacement sensor under the acceleration stress level;

[0017] ② Change the acceleration stress level, repeat step ①, measure the repeatability of the nano-time-grating displacement sensor under different acceleration stress levels, and obtain different standard deviation values.

[0018] Furthermore, the moving speed of the moving ruler of the nano-time grating displacement sensor is 15 to 20 mm / s.

[0019] Furthermore, when the standard deviations corresponding to two or more acceleration stress levels are the same and are all minimum values, the minimum acceleration stress level is not unique, and the minimum acceleration factors under different minimum acceleration stress levels are taken as the acceleration factors of the electronic devices of the nano-time grating displacement sensor.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] The present invention provides a method for determining the acceleration factor of the electronic device of a nano-time-grating displacement sensor. This method uses the electronic device at the lowest nominal operating temperature as the research object, determines the accelerated test temperature range, then measures the repeatability of the nano-time-grating displacement sensor under different acceleration stress levels, and determines the minimum acceleration stress level by minimizing the standard deviation. The acceleration factor at the minimum acceleration stress level is then calculated using the Arrhenius model, and the acceleration factor of the electronic device of the nano-time-grating displacement sensor is comprehensively determined by minimizing the acceleration factor. Finally, the reliability life of the electronic device of the nano-time-grating displacement sensor can be obtained by extrapolating the acceleration factor, without the need for long-term testing under natural conditions to verify its reliability life. This effectively solves the problem that the natural storage test cycle of the electronic device of the nano-time-grating displacement sensor is too long and cannot meet the iterative requirements of product development. This method fills the gap in the existing technology in the lack of a method for determining the acceleration factor of a nano-time-grating displacement sensor, and provides theoretical support for the reliability design and life assessment of nano-time-grating displacement sensor products. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a flow chart of the method for determining the acceleration factor of the nano-time grating displacement sensor product of the present invention. DETAILED DESCRIPTION

[0023] The specific implementation methods of the present invention are further described in detail below with reference to specific examples.

[0024] There are three types of accelerated life models for electronic components in the industry:

[0025] (1) High temperature working life, using the Arrhenius accelerated test model;

[0026] (2) Temperature cycling, using the Coffin-Manson accelerated test model;

[0027] (3) High temperature and high humidity double 85, using the Hallberg-Peck acceleration model.

[0028] Since the nanometer time-grating displacement sensor does not need to work in a temperature cycle or high temperature and high humidity environment during practical application, the present invention selects the Arrhenius acceleration test model to study the acceleration factor.

[0029] Based on the above research, the present invention provides a method for determining the acceleration factor of the electronic device of the nano-time grating displacement sensor, the flow chart is as follows: Figure 1 As shown, the following steps are included:

[0030] (1) Determine the nominal operating temperature of each electronic component of the nanometer time-gate displacement sensor, and then determine the ambient temperature range of the accelerated test based on the lowest nominal operating temperature; assuming that the lowest nominal operating temperature is x°C, the ambient temperature range is x-25 to x°C;

[0031] (2) measuring the repeatability of the nano-time-grating displacement sensor under different acceleration stress levels, and using the standard deviation to represent the repeatability, taking the acceleration stress level corresponding to the minimum standard deviation as the minimum acceleration stress level; the acceleration stress level is composed of two variables: the input voltage and the ambient temperature of the acceleration test; the input voltage is any value in the rated input voltage of the nano-time-grating displacement sensor, and the ambient temperature is any value within the ambient temperature range described in step (1);

[0032] In a specific implementation, the input voltage is the maximum value, minimum value or intermediate value of the rated input voltage, and the ambient temperature is several temperature points with a temperature interval of 5°C or 10°C. The input voltage and ambient temperature are cross-matched to obtain different acceleration stress levels.

[0033] It should be noted that since the acceleration stress levels (input voltage and ambient temperature) cannot be exhaustively enumerated, in actual measurements, only a few points within the input voltage range and ambient temperature range need to be selected for accelerated test measurements. The input voltage values are the maximum, minimum, and intermediate values of the rated input voltage for repeatability measurement; and the temperature intervals of the ambient temperature points selected for the accelerated test can be 5°C, 10°C, or 15°C, depending on actual needs. The narrower the temperature interval, the more accurate the measured acceleration factor. However, in actual measurements, due to cost considerations and the technical personnel's acceptance of the error in the measured acceleration factor, the technical personnel are willing to accept the possible deviation of the measured acceleration factor under the temperature interval of 5°C or 10°C, so the temperature interval is preferably 5°C or 10°C.

[0034] (3) Using the Arrhenius model to calculate the corresponding acceleration factor at the minimum acceleration stress level, the acceleration factor at the minimum acceleration stress level is taken as the acceleration factor of the electronic device of the nano-time grating displacement sensor;

[0035] The Arrhenius model is as follows:

[0036]

[0037] Where AF is the acceleration factor, Ea is the activation energy corresponding to the lowest nominal operating temperature of the electronic device, k is the Boltzmann constant, T1 is the ambient temperature corresponding to the minimum acceleration stress level, and T2 is room temperature (25°C). The value range of Ea is -0.2 to 1.4 eV; k = 8.61733*10 -5 eV / K.

[0038] The activation energy corresponding to the electronic device with the lowest nominal operating temperature is calculated using the following formula:

[0039] Ea=k*(ln(λa)-ln(λn)) / (1 / Tn-1 / Ta)

[0040] In the above formula, λa is the failure rate of the electronic device with the lowest nominal operating temperature at the accelerated temperature Ta corresponding to the minimum accelerated stress level, λn is the failure rate of the electronic device with the lowest nominal operating temperature at the normal temperature Tn (25°C), Tn and Ta are both absolute temperatures K, and k is the Boltzmann constant.

[0041] Among them, λa and λn are calculated by the following formula:

[0042] λ=(C1*π T *π V +(C2+C3)*π E )*π Q *π L

[0043] C1 and C2 are both circuit complex failure rates, C3 is the package complex failure rate, π E is the environmental coefficient, π Q is the mass coefficient, π L is the maturity coefficient, π T is the temperature coefficient, π V is the voltage stress coefficient, C1, π T , π V 、C2、C3、π E , π Q , π L All of them are obtained by consulting the tables in the Handbook of Reliability Prediction of Electronic Equipment (GJB / Z 299C-20065.2.2).

[0044] In specific implementation, λa and λn can also be obtained through experiments, but it takes a long time to test, and the failure rate of new products is difficult to obtain in a short time.

[0045] In specific implementation, when the standard deviations corresponding to two or more acceleration stress levels are the same and are all minimum values, the minimum acceleration stress level is not unique, and the minimum acceleration factor under different minimum acceleration stress levels is taken as the acceleration factor of the electronic device of the nano-time grating displacement sensor.

[0046] The repeatability is measured by the following method:

[0047] ① Under the same acceleration stress level, the moving ruler of the nano-time grating displacement sensor moves at a constant speed (15-20 mm / s) along the set path until it reaches the end of the set path, then returns to the original path at the same speed and moves back and forth several times; during the movement, the displacement data of the moving ruler moving to the set time point is continuously collected. After the collection is completed, the standard deviation of the displacement data corresponding to the set time points during the process of the moving ruler moving from the starting point to the end of the set path is calculated, and the minimum standard deviation is taken as the repeatability of the nano-time grating displacement sensor under the acceleration stress level;

[0048] ② Change the acceleration stress level, repeat step ①, measure the repeatability of the nano-time-grating displacement sensor under different acceleration stress levels, and obtain different standard deviation values.

[0049] Example

[0050] This embodiment discloses a method for determining an acceleration factor of an electronic device of a nano-circular time-grating, comprising the following steps:

[0051] (1) Determine the minimum nominal operating temperature of each electronic component of the SAE128 circular time-gate to be 85°C (the nominal temperatures of each electronic component are: 85°C for the integrated circuit; 125°C for the resistor; 125°C for the capacitor; 130°C for the inductor; 150°C for the field-effect transistor; and 150°C for the diode, so the minimum nominal operating temperature is 85°C). Based on the minimum nominal operating temperature, determine the operating temperature range of the accelerated test to be 60-85°C, and determine the rated input voltage of the nanometer time-gate displacement sensor (4.75-5.25V).

[0052] (2) The repeatability of the nanometer time-grating displacement sensor under different voltage and temperature conditions was measured, and the standard deviation was used to represent the repeatability. The statistical results are shown in Table 1.

[0053] This embodiment uses a temperature interval of 10°C as the standard for measurement. The measured temperature points should be 60°C, 70°C, and 80°C. However, considering that when the ambient temperature is 80°C, the self-heating of the electronic components during operation may cause the operating temperature to exceed the minimum operating nominal temperature (85°C), making the nano-time grating displacement sensor extremely easy to be damaged, making the measured results not of reference value. Therefore, the repeatability at 75°C was measured by lowering the temperature by 10°C from 85°C.

[0054] Table 1 Comparison of standard deviations at different accelerated stress levels

[0055]

[0056] (3) Take the acceleration stress level corresponding to the minimum standard deviation as the minimum acceleration stress level. From Table 1, we can see that the minimum acceleration stress level corresponding to the minimum standard deviation σ is: voltage 5.00V; load 0.250A; temperature 60℃;

[0057] (4) The activation energy of the electronic components corresponding to the lowest nominal operating temperature is determined (Ea = 0.67 eV), and the acceleration factor corresponding to the minimum acceleration stress level (60 ° C) is calculated using the Arrhenius model. The acceleration factor of the electronic device of the nano-time grating displacement sensor is 15.483.

[0058] Acceleration factor accuracy verification experiment;

[0059] (1) Calculate the reliability life (MTBF) of the electronic components of the nanometer time-grating displacement sensor

[0060] MTBF=1 / λ 累积

[0061] In the above formula, λ 累积 is the cumulative failure rate of electronic devices at room temperature (25°C) (i.e. the sum of the failure rates λ of all electronic components) λ=(C1*π T *π V +(C2+C3)*π E )*π Q *π L , where C1 and C2 are circuit complex failure rates, C3 is package complex failure rate, π E is the environmental coefficient, π Q is the mass coefficient, π L is the maturity coefficient, π T is the temperature coefficient, π V is the voltage stress coefficient, C1, π T , π V 、C2、C3、π E , π Q , π L All of them are obtained by consulting the tables in the Handbook of Reliability Prediction of Electronic Equipment (GJB / Z 299C-20065.2.2).

[0062] Through calculation, we get: MTBF = 299638h.

[0063] (2) Calculate the accelerated equivalent verification time Tacc

[0064] Tacc=AF*Sample*ACpower*DCpower*Tsum / GEM

[0065] In the above formula, AF is the acceleration factor of the nanometer time-grating displacement sensor's electronics, Sample is the number of nanometer time-grating displacement sensors, ACpower is the power-up cycle factor, DCpower is the duty cycle, Tsum is the planned test run time, and GEM is the time composite index. Here, AF = 15.483, ACpower = 1, DCpower = 1, and Tsum = 900h.

[0066] GEM is the time comprehensive index when the quality of the nano-time grating displacement sensor is guaranteed at a 90% confidence level and no faults occur. At this time, GEM is 2.3026.

[0067] (3) When the accelerated equivalent verification time is greater than or equal to the MTBF, and the nanometer time grid sensor does not fail within the test time of the accelerated equivalent verification, it is proved that the acceleration factor is accurate.

[0068] Therefore, this example selected 50 sets of nano-time-grating displacement sensors for simultaneous verification. At this time, Tacc = 302591h, which is greater than the MTBF, verifying the reliability lifespan of the nano-time-grating sensors. It was also observed that no nano-time-grating sensors failed during the equivalent verification test time (891.2h), indicating that the acceleration factor measured in this example is accurate. The actual test time Duration is calculated using the following formula:

[0069] Duration=(MTBF*GEM) / (DCpower*Sample*ACpower*AF)=891.2h

[0070] In the above formula, MTBF is the expected reliability lifespan, AF is the acceleration factor of the nanometer time-grating displacement sensor's electronic components, Sample is the number of nanometer time-grating displacement sensors, ACpower is the power-on cycle factor, DCpower is the duty cycle, and GEM is the time composite index. Here, AF = 15.483, ACpower = 1, DCpower = 1, GEM = 2.3026, and MTBF = 299638h.

[0071] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit the technical solutions. Those skilled in the art should understand that modifications or equivalent replacements of the technical solutions of the present invention that do not depart from the purpose and scope of the technical solutions of the present invention should be included in the scope of the claims of the present invention.

Claims

1. A method for determining the acceleration factor of an electronic device of a nanometer time-grating displacement sensor, characterized in that: The following steps are involved: (1) Determine the nominal operating temperature of each electronic component of the nanometer time-gate displacement sensor, and then determine the ambient temperature range of the accelerated test based on the lowest nominal operating temperature; assuming that the lowest nominal operating temperature is x°C, the ambient temperature range is x-25 to x°C; (2) measuring the repeatability of the nano-time-grating displacement sensor under different acceleration stress levels, and using the standard deviation to represent the repeatability, taking the acceleration stress level corresponding to the minimum standard deviation as the minimum acceleration stress level; the acceleration stress level is composed of two variables: the input voltage and the ambient temperature of the acceleration test; the input voltage is any value in the rated input voltage of the nano-time-grating displacement sensor, and the ambient temperature is any value within the ambient temperature range described in step (1); (3) Using the Arrhenius model to calculate the corresponding acceleration factor at the minimum acceleration stress level, the acceleration factor at the minimum acceleration stress level is taken as the acceleration factor of the electronic device of the nano-time grating displacement sensor; The Arrhenius model is as follows: Where AF is the acceleration factor, Ea is the activation energy corresponding to the electronic device with the lowest nominal operating temperature, k is the Boltzmann constant, T1 is the ambient temperature corresponding to the minimum acceleration stress level, and T2 is room temperature.

2. The method for determining the acceleration factor of the electronic device of the nanometer time-grating displacement sensor according to claim 1, characterized in that: The value range of Ea is -0.2 to 1.4 eV.

3. The method for determining the acceleration factor of the electronic device of the nanometer time-grating displacement sensor according to claim 1, characterized in that: In step (2), the input voltage is the maximum value, minimum value or intermediate value of the rated input voltage, and the ambient temperature is several temperature points with a temperature interval of 5°C or 10°C. The input voltage and ambient temperature are cross-matched to obtain different acceleration stress levels.

4. The method for determining the acceleration factor of the electronic device of the nanometer time-grating displacement sensor according to claim 1, characterized in that: The repeatability is measured by the following method: ① Under the same acceleration stress level, the moving ruler of the nano-time grating displacement sensor moves at a constant speed along the set path until it reaches the end point of the set path, then returns to the original path at the same speed and moves back and forth several times; during the movement, the displacement data of the moving ruler moving to the set time point is continuously collected. After the collection is completed, the standard deviation of the displacement data corresponding to the set time points during the process of the moving ruler moving from the starting point to the end point of the set path is calculated, and the minimum standard deviation is taken as the repeatability of the nano-time grating displacement sensor under the acceleration stress level; ② Change the acceleration stress level, repeat step ①, measure the repeatability of the nano-time-grating displacement sensor under different acceleration stress levels, and obtain different standard deviation values.

5. The method for determining the acceleration factor of the electronic device of the nanometer time-grating displacement sensor according to claim 4, characterized in that: The moving speed of the moving ruler of the nano-time grating displacement sensor is 15 to 20 mm / s.

6. The method for determining the acceleration factor of the electronic device of the nanometer time-grating displacement sensor according to claim 1, characterized in that: When the standard deviations corresponding to two or more acceleration stress levels are the same and are all minimum values, the minimum acceleration stress level is not unique, and the minimum acceleration factors under different minimum acceleration stress levels are taken as the acceleration factors of the electronic devices of the nano-time grating displacement sensor.

Images