Quantifying Microvia Plating Fatigue and Target Pad Separation Rates under Rapid Thermal Cycling
Continuous high-speed Kelvin monitoring during rapid thermal cycling isolates latent target pad separations that re-nest and pass static ambient tests.
Shape Parameter Beta
Distribution Constant
Statistical analysis of component failures uses a specific value to describe the slope of the weibull distribution curve. The shape parameter beta indicates whether the failure rate of a population is increasing or decreasing over time. This value is derived from testing a sample of boards until they fail and plotting the results on a probability scale.
Failure Mode
Values of this constant that are less than one suggest that infant mortality is the primary cause of breakdown. When the shape parameter beta equals one, the failures occur randomly and are not related to the age of the circuit. A value greater than one signifies that the product is reaching the end of its useful life and is failing due to wear out mechanisms like electromigration.
This distinction is critical for identifying whether a batch of boards was damaged during assembly or if the design itself is fundamentally flawed.
Population Trend
Understanding this metric helps engineers determine the appropriate warranty period and maintenance schedule for an electronic system. If the shape parameter beta is very high, the product will have a long period of reliable operation followed by a sudden cluster of failures. This pattern is typical for well built circuit boards that are reaching their thermal cycling limit.