Understanding Thermal Shock and the Coffin-Manson Model in Microelectronics

Consumer electronics—like smartphones, laptops, and tablets—must withstand frequent power cycles and ambient temperature changes. One of the most critical reliability challenges is thermal shock: rapid temperature changes that cause expansion and contraction, leading to material fatigue.

The Coffin-Manson Model: Predicting Fatigue Life

The Coffin-Manson equation helps engineers estimate the number of cycles a material can withstand before failure under cyclic thermal stress:

N_f = C \cdot (\Delta\varepsilon_p)^{-k}

Where:

N_f: Number of cycles to failure
C: Material constant (empirically determined)
Δε_p: Plastic strain range per cycle (proportional to ΔT)
k: Coffin-Manson exponent (typically 1.5–2.5 for solder joints)

This equation shows that as temperature swing increases, the number of cycles to failure decreases rapidly—a critical insight for designing reliable microelectronics.

Graph: Cycles to Failure vs. Temperature Delta

The graph below illustrates how fatigue life decreases as thermal stress increases:

Coffin-Manson fatigue life prediction graph for solder joints under thermal cycling

What Physics-of-Failure Does Thermal Shock Address?

The Coffin-Manson model specifically addresses low-cycle fatigue, where materials—particularly solder joints and interfaces—fail due to repeated thermal expansion and contraction.

Over time, cyclic strain leads to microcracks in solder joints, eventually causing open circuits and intermittent failures. This is a key concern for SMT, BGA, QFN, and other fine-pitch components in consumer electronics.

Real-World Applications: Microelectronics Under Thermal Shock

Thermal shock is a critical concern for devices like smartphones and laptops. Charging, CPU loads, and outdoor usage lead to temperature swings that stress components. Solder joints and interconnects are the most vulnerable.

Want to understand how thermal shock impacts your design? Use our Coffin-Manson Calculator to estimate fatigue life based on thermal cycles.

Limitations and Best Practices

The model assumes strain-controlled fatigue—other mechanisms may dominate in some cases.
Material constants (C, k) vary with solder alloy, pad geometry, and board structure.
Combine simulation with physical testing for accurate validation.

Conclusion: Designing for Durability

The Coffin-Manson model is essential for understanding fatigue from thermal cycling in microelectronics.

With predictive tools like our Coffin-Manson Calculator, engineers can make smarter design decisions and ensure devices remain reliable in everyday use.