Use of polymer and plastic materials in electronics applications from the reliability point of view

Polymer and plastic materials are used increasingly in electtonics applications. Not only are they used as insulating materials, but they are also widely used as structural components, protective materials, and even as electrically conductive materials. Polymers have many considerable advantages compared to metals and ceramics. These include for example lightness, low cost, ease of manufacturing, and high versatility. New polymer materials have been developed for many applications and this has further increased their use in electtonics for example as structural parts. Furthermore, polymers are commonly used as a part of composite materials which enables their use in new applications such as electrically conductive materials. From the reliability point of view polymers may be problematic as they are typically less stable than the ceramic and metal materials they are used to replace. Most polymers have poor thermal properties, which needs to be taken into account when they are used. Additionally, humidity and other environmental conditions may markedly decrease the mechanical and electrical properties of these materials. Accelerated life testing (ALT) is commonly used to assess the reliability of various structures and materials used in electtonics. This is important especially when new structures and materials are designed. When metals and ceramics are replaced with polymers, environmental test conditions may need to be considered again, as the standard test conditions or previously used test conditions may not be meaningful anymore. Consequently, careful consideration of accelerated test conditions is needed with polymer materials to ensure that they accelerate correct failure mechanisms.