Electronics are continually being improved and developed, but the components they are made up of are only becoming more sensitive, leading to failures during their operational life. Some of the most common electronic component failures include mechanical, thermal, and environmental failure, electrical stress, packaging issues, and inevitable aging. In this blog, we will outline the aforementioned causes of failure in detail, allowing you to better understand how they can be readily identified.
What Is Mechanical Failure?
Mechanical failure in a circuit board is usually characterized by elastic and plastic deformation, fatigue fracture initiation, propagation, brittle fracture, warpage, and creep fracture.
Deformation is simply defined as the distortion in shape and size of an object, of which there are two types: elastic and plastic. Elastic deformation is temporary and goes away once external forces that cause stress and alteration have been removed. Plastic deformation, on the other hand, is permanent and retains the distorative effects.
Brittle fracture occurs when rapid cracking of electronic equipment under stress takes place. It is worth noting that the material may show no signs of degradation or breakage until failure occurs, but in circuits boards specifically, this type of failure presents itself in the soldered joints. These fractures are usually the result of tensile stresses during assembly, testing, and transport.
Warpage is the twisting or bending of a device due to exposure to heat or moisture. Warping will often change the profile of the board during the reflow soldering cycle. Unbalanced layers during board design, thermal expansion during soldering, and weight can be significant causes of warpage.
Creep fracture is considered a time-dependent deformation attributed to an increase in temperature and constant pressure.
Fatigue is the initiation and development of cracks in a material due to cyclic loading. In PCBs, solder fatigue is quite common, and it is usually caused by inconsistent CTE which determines the contraction and expansion of the material during temperature fluctuations.
What Is Thermal Failure?
Thermal failure happens when the component is heated above its normal operating temperature, such as the glass transition temperature (Tg), melting point, or flashpoint. Tg is the temperature where the base material changes from a rigid to elastic state.
What Is Environmental Failure?
Environmental failure, as the name suggests, results from the entry of foreign objects, debris, power surges, and exposure to heat.
What Is Electrical Stress Failure?
Electrical stress failure is the result of electrostatic discharge (ESD), surface breakdown, dielectric failure, overvoltage, and surface trapping.
Extreme electrical stress causes ESD, which leads to catastrophic failure, permanent parameter variation, and hidden damage. High current density, high electric field gradients, and localized heat formation are all common causes as well.
Dielectric failure is defined as the electric breakdown within a solid insulator situated between two conductors, and it is associated with the puncture or decomposition of the insulation material.
Over time, boards may develop conductive anodic filaments (CAFs) along the composite material fibers. During the via plating, metal is injected into an exposed surface and migrates due to ions, moisture, and electrical potential. PBC drilling damage and poor glass-resin bonding contribute to such failures.
What Is Packaging Failure?
Due to the fact that packaging is meant to act as a barrier between electronic components and environmental influences, you may be surprised to find out that packaging failure is a common cause of breakdowns in many electronic parts. Thermal expansion leads to mechanical stresses that damage materials. Additionally, aggressive chemicals and humidity can corrode certain components.
What Is Aging Failure?
While we may want our electronics to last forever, that is just not the case for most devices. However, with the proper care and maintenance, their service lives can be extended, allowing you to better take advantage of them.
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