This paper investigates the effects of three ageing factors (chemical, humidity, and temperature) and their interactions on the physical properties and degradation of silicone sealant used in microelectronic applications. The thermal degradation of silicone sealants was investigated by exposing samples to temperatures in the range of 150 up to 175 °C. Also, a set of samples were aged at 40 °C in a salt spray set-up with 100 % humidity in a salty atmosphere. Results showed detectable changes in the FTIR spectra of aged specimen as compared with the as-received sample. In all accelerated testing conditions, peak intensities decreased with ageing time, inferring that that the surface characteristics of the sealant is affected by ageing. Shear test results showed that with increasing the ageing time, the maximum shear stress in most cases has decreased in all ageing conditions. Also, it appears that samples with longer ageing times have experienced more elongation before failure. Results also show that salt spraying of specimens is associated with a decrease in the mechanical properties of the sealant, indicating the deleterious implications of ionic contaminations for the mechanical properties of samples.

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Adhesive bonding is a key joining technology in many industrial applications, including automotive, aerospace industries, biomedical devices, and microelectronic components. Adhesive bonding is gaining more and more attention due to the increasing demand for joining similar or dissimilar components, mostly within the framework of designing lightweight structures. Silicone sealant is widely used in engineering application due to its thermal stability, excellent energy absorption, and good damping characteristics. In those applications, sealant usually exposed to various environment stress, such as, high temperature, mechanical stress, humidity, light radiation, and chemical attack. Long-term stability and durability of sealant is crucial to the performance of the associated application. The main degrading factors for silicone in microelectronic applications are temperature, humidity, alkali, and mechanical loading. The focus in the present paper is to understand different failure mechanisms in silicone sealants and adhesives and to study how different environmental, mechanical, and service-related stresses attribute to the kinetics and extent of degradation in silicone sealants and adhesives. The impact of different failure mechanisms on the lifetime and reliability of microelectronic devices will be methodically investigated.@en