With the vigorous development of the automotive industry, more and more manufacturers have shifted from the general consumer electronics industry to the automotive electronics industry. The biggest difference comes from the difference in the life cycle. The life cycle of the consumer electronics industry is about 3 to 5 years, but The automotive industry is related to personal life safety, and generally requires a life cycle of more than 10 years, so the relevant reliability verification is more important, and today I want to talk about a project of automotive reliability verification - Board Level Reliability (Board Level Reliability) Reliability, BLR) test is the reliability test of solder joints after the automotive components are on the board.
Automotive electronic systems are becoming more and more advanced, which also means that in the automotive industry, IC components will be used more and more. Therefore, it is necessary to use BLR test to quickly find out the failure mode. It is also commonly used to verify the soldering of IC components on the board to PCB. Point strength test to ensure product life, AEC-Q104 standard formulated by AEC Automotive Electronics Association, which clearly defines the reliability test items of automotive electronics in BLR, BLR common tests are as follows, temperature cycle and shock, mechanical stress shock Strength of joint position with solder joints (push force, tensile force, bending test), compound vibration test, plate bending test, etc.
Common reliability factors that affect BLR are as follows,
- PCB material, thickness, through hole design,
- PCB pad design,
- solder ball material,
- wafer position and size and its corresponding position to solder balls,
Among them, the choice of solder ball material has a particularly significant impact on the reliability test results.
The following introduces several board level reliability tests and the functions of JMP related analysis.
- Steady state test: mainly through high temperature and high humidity (acceleration factor), to verify and evaluate the degree of impact on the material and circuit of the unsealed packaged components, such as the solder joint will cause short circuit due to the influence of temperature and humidity and affect the life.
- Mechanical stress test: Some use non-soldering methods to connect, such as gold fingers, USB connectors, etc., for some tests to simulate the influence of external stress on life, such as abnormal resistance value.
- Plate bending test: Through the external stress test, the influence of the solder joints and material structure of the parts can be confirmed, and the ability of the product to withstand fatigue can also be understood, such as the breaking of the tin spherical surface and the open circuit.
- Temperature Cycling and Shock Testing: Confirm the effect of accelerated aging factors on products, such as tin cracking, through thermal cycling or thermal shock with rapid temperature changes.
Tin crack
short circuit
warped plate
The following introduces JMP Related application analysis functions
Ø Acceleration factor to life distribution analysis (Fit Life by X)
Because the probability of product failure is very low under normal conditions, the probability of product failure is accelerated through the setting of some conditions, such as the environment. Common acceleration factors include temperature, voltage, pressure, etc., and the platform also includes data conversion. Arrhenius transformation, also includes linear, logarithmic, reciprocal, square root, etc. transformations. JMP also provides a dedicated reliability experimental design platform to design acceleration factor versus lifetime experiments.
Check for differences between groups at different temperatures
Add acceleration factor to life prediction
Displays a scatter plot between acceleration factor and predicted life
Compare the results of each distribution fit
Ø Accelerated life experiment design
Because of the high reliability of the product or the need to understand the test results of the product in a short time, additional experiments are required to understand the reliability results of the product. On the accelerated experimental design platform, the number of existing experiments can also be expanded to reduce estimation errors.
Establish accelerated experiments based on prior distribution or experience, and estimate failure probability
Use a simulator to simulate the estimation results
JMP also has many analysis methods on the reliability analysis platform, such as life analysis, degradation analysis, etc. Today, it mainly introduces the accelerated life analysis platform, explaining whether it is the acceleration factor analysis of automobiles or the acceleration factors of other industries. For analysis, you can use this platform. You do not need to use multiple platforms for multiple analysis and drawing, which saves analysis time. In addition, there are more platforms for designing accelerated experiments, which provide you with designing experiments and confirming the distribution of data, which strengthens the experimenter. I don’t know how to design an experiment to verify this. Of course, the reliability of the car is not limited to this. This brief introduction to the verification of the board level reliability and the JMP-related platform can provide the automotive-related industry with a quick understanding of the reliability results for subsequent analysis. .
