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Environmental factors and testing
Published in Stephen Sangwine, Electronic Components and Technology, 2018
A less obvious, but very important, effect of temperature is a reduction in the reliability of a product when operating at an elevated temperature or when subjected to repeated variation in temperature (thermal cycling). One way in which temperature and temperature cycling reduce reliability is by the creation of mechanical stresses within components and joints by differential thermal expansion, which may lead to fracture. This problem occurs with ceramic chip carriers soldered to epoxy–fibreglass printed circuit boards (PCBs), for example, where the temperature coefficient of expansion (TCE) of the ceramic (about 6 parts per million [p.p.m.] °C−1) and the epoxy–fibreglass (about 12 to 16 p.p.m. °C−1) are sufficiently different to make this method of mounting unreliable because of solder joint fracture after temperature cycling.
Methodology for the preparation of accelerated reliability testing of electronic components in combat vehicles
Published in Stein Haugen, Anne Barros, Coen van Gulijk, Trond Kongsvik, Jan Erik Vinnem, Safety and Reliability – Safe Societies in a Changing World, 2018
When performing the ART of electronic components in combat vehicles, there are four types of stress should be focused, namely temperature cycling, temperature, humidity and vibration. The temperature is the basic stress of electronic components. It is sometimes said that temperature is the enemy of reliability of all electronic components. Whether they are used for commercial or military, these components are stressed by the environmental temperature when turned off and the operating temperature when turned on. The temperature cycling which particularly stresses on the solder joints of the electronic components results in a total failure of the electronic components (for example breaking of solder joints, loss of conductive contact, and deformation of the processor plate). The basic factors that affect the failure rate of electronic components by temperature cycling are: Type of solder is used and its properties;Temperature rise in electronic components;Minimum temperature difference (e.g., on/off).
Thermal Management and Reliability
Published in Dorin O. Neacsu, Switching Power Converters, 2017
Another accelerated test procedure refers to temperature cycling. This time, the effect of temperature change on the equipment’s lifetime is calculated. Each time the equipment powers up from ambient temperature to the actual operation, there is a gradient of temperature than influences the time-to-failure. This test is very important for the validation of the packaging and overall assembly and it does not require electrical power in the circuit. The device is heated and cooled by an external heat source, like an oven, to produce the variation in ΔTjc. Materials have different thermal expansion coefficients and the temperature cycling induces certain failures due to the thermo-mechanical expansion. Such failures can be package cracking, die cracking, wire-bond lift-off, and an increase in contact resistance.
Reliability Prediction Methods for Electronic Devices: A State-of-the-art Review
Published in IETE Technical Review, 2022
Vinay Kumar, Lalit Kumar Singh, Anil Kumar Tripathi
Due to thermal shock and temperature cycling, electronic devices usually suffer from fatigue failures. Temperature cycling testing is used to accelerate life testing for the product, exposed to a significant change in temperature during its run time. A rapid change in the product's temperature due to repeated switch on and off causes self-heating of the product. Those repeated changes in temperature may lead to thermal fatigue. i.e. weaken the product materials due to such stress and may cause different types of failures. Coffin-Manson Model [25] for fatigue addressed such types of fatigue, and mathematically, this model can be represented as, where, : no. of failure cycles; coefficient and cycling frequency, respectively; : cycling frequency exponent and temperature exponent, respectively; : temperature range during a cycle; : Arrhenius term evaluated at a max temperature in every cycle;