Device reliability evaluation method based on transient thermal process

Abstract

The invention discloses a device reliability evaluation method based on a transient thermal process. According to the invention, the transient temperature rise of the device is evaluated based on the transient thermal network parameters of the device and the power consumption of the device under the current working condition; and then the transient temperature rise of the device is substituted into an Arenius model to obtain the failure rate F of the device under the working condition, and then the reliability and the average life of the device under the specific working condition are obtained based on an exponential distribution model. According to the method, the transient thermal process of the device and the difference of the failure rates under the application working condition are fully considered, accurate evaluation of the reliability of the device is achieved, a complex simulation model does not need to be built, and the method has good engineering applicability.

Description

Technical Field

[0001] The present invention relates to the field of reliability technology, and in particular to a device reliability evaluation method based on transient thermal process. Background Art

[0002] When the system is working, it will generate heat, which changes the working environment of the system components, causing the working efficiency and reliability of the components to be different from the component parameters or component performance provided by the component supplier. These changes in component parameter performance caused by temperature changes will eventually affect the changes in the life of the device and system. Every component in the system has a chance of failure when the system is overheated, thereby reducing the reliability of the system. According to the survey, 50% of electronic component failures are caused by unexpected thermal control failures.

[0003] At present, in engineering applications, empirical formulas are usually used to estimate the end of device life caused by thermal failure: the device life is reduced by half for every 10°C increase in operating temperature. Another reliability evaluation method is obtained based on statistical methods in the field of reliability engineering according to GJB299C. The reliability distribution usually adopts exponential distribution, which is a single-parameter distribution and satisfies R(t) = e -λt , where λ is the failure rate. However, this exponential distribution is only applicable to the case where the failure rate λ is constant. The failure rate λ is the inverse of the mean time to failure MTTF, which is numerically the average life of the device when R(t) = 0.38.

[0004] According to the above reliability assessment method, the empirical formula needs to obtain the operating temperature of the device. Usually, the operating temperature of the device is calculated by the product of loss and thermal resistance or obtained through thermal simulation. It only considers the impact of thermal resistance on the operating temperature and does not consider the transient temperature change caused by thermal capacitance. At the same time, the failure rate of the device in the GJB299C exponential distribution method is a constant value, and does not consider the differences in failure rates under different application conditions. It is not suitable for engineering use. Summary of the invention

[0005] In view of this, the present invention provides a device reliability assessment method based on transient thermal processes, which takes into account transient temperature changes caused by heat capacity and differences in failure rates under application conditions, and is suitable for use in engineering.

[0006] The device reliability evaluation method based on transient thermal process of the present invention comprises:

[0007] Step 1, obtain the transient thermal network parameter RC of the device and the power consumption P of the device under the current working condition, and evaluate the transient temperature rise △T of the device; where R is the total thermal resistance and C is the total thermal capacity;

[0008] Step 2, bringing the transient temperature rise of the device obtained in step 1 into the Arrhenius model to obtain the failure rate F of the device under working conditions;

[0009] Step 3, the failure rate F obtained in step 2 is substituted into the exponential distribution model to obtain the reliability of the device under specific working conditions.

[0010] Preferably, in step 1, the transient temperature rise ΔT of the device is:

[0011]

[0012] Where: τ = RC, E = PR is the device power consumption.

[0013] Preferably, the transient thermal network parameter RC of the device is obtained from the device manufacturer's specification sheet.

[0014] Preferably, in step 2, the Arrhenius model is:

[0015]

[0016] Among them, A is the general life of the device provided by the manufacturer; E=PR is the device power consumption; K is the Boltzmann constant; T is the device junction temperature, T=T0+△T, T0 is the ambient temperature unit ℃.

[0017] Beneficial effects:

[0018] The present invention evaluates the transient temperature rise of the device based on the transient thermal network parameters of the device and the power consumption of the device under the current working condition; then the transient temperature rise of the device is brought into the Arrhenius model to obtain the failure rate F of the device under the working condition, and then the reliability and average life of the device under specific working conditions are obtained based on the exponential distribution model. The present invention fully considers the transient thermal process of the device and the differences in failure rates under application conditions, realizes accurate evaluation of device reliability, and does not need to build a complex simulation model, and has good engineering applicability. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a flow chart of the present invention. DETAILED DESCRIPTION

[0020] The present invention is described in detail below with reference to the accompanying drawings and embodiments.

[0021] The present invention provides a device reliability evaluation method based on transient thermal process, the method flow chart is as follows: Figure 1 As shown, specifically including:

[0022] S1, according to the data such as the specification provided by the device manufacturer, obtain the general life A of the device and the transient thermal network parameter RC of the device, where R is the total thermal resistance and C is the total thermal capacity;

[0023] S2, calculate the power consumption P of the device under the current working condition;

[0024] S3, using the device transient thermal network parameters, evaluate the device transient temperature rise △T:

[0025]

[0026] Where: τ = RC, E = PR is the device power consumption, unit is eV.

[0027] S4, bring the transient temperature rise of the device into the Arrhenius model to obtain the failure rate F of the device under working conditions.

[0028] From the perspective of a single device, when the temperature exceeds the limit value, the component will fail. The relationship between temperature and failure rate grows exponentially, which conforms to the Arrhenius model:

[0029]

[0030] Where: F is the failure rate; A is a constant; E = PR is the device power consumption, in eV; K is the Boltzmann constant, K = 8.6173*10-5E V / K; T is the device junction temperature, T=T0+△T, T0 is the ambient temperature unit ℃.

[0031] S5, the failure rate F is introduced into the exponential distribution model to obtain the reliability and average life L of the device under specific working conditions.

[0032] The exponential distribution is a single-parameter distribution, satisfying R(t) = e -λt , the mean time to failure MTTF is mathematically the average life of the life parts when R(t) = 0.38. Therefore, the failure rate F is introduced into the exponential distribution model, and R(t) = e -Ft , when R(t)=0.38, the average life of the device is L=1 / F.

[0033] In summary, the above are only preferred embodiments of the present invention and are not intended to limit the protection scope of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A device reliability assessment method based on transient thermal process, characterized in that: include: Step 1, obtain the transient thermal network parameter RC of the device and the power consumption P of the device under the current working condition, and evaluate the transient temperature rise △T of the device; where R is the total thermal resistance and C is the total thermal capacity; Step 2, bringing the transient temperature rise of the device obtained in step 1 into the Arrhenius model to obtain the failure rate F of the device under working conditions; Step 3, the failure rate F obtained in step 2 is substituted into the exponential distribution model to obtain the reliability of the device under specific working conditions.

2. The method according to claim 1, characterized in that In step 1, the transient temperature rise ΔT of the device is: Where: τ = RC, E = PR is the device power consumption.

3. The method according to claim 1, characterized in that The transient thermal network parameter RC of the device is obtained from the device manufacturer's specification sheet.

4. The method according to claim 1, 2 or 3, characterized in that: In step 2, the Arrhenius model is: Among them, A is the general life of the device provided by the manufacturer; E=PR is the device power consumption; K is the Boltzmann constant; T is the device junction temperature, T=T0+△T, T0 is the ambient temperature unit ℃.

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