For any type of metal-based interconnections, intermetallic compounds (IMC) are needed to ensure the contact between different electronic chip layers. The connection between solder and direct copper bonded (DCB) is only possible through the intermetallic compounds (IMCs) such as Cu6Sn5 and Cu3Sn in Cu-Sn soldering system in diffusion soldering process. The IMCs are brittle in nature compared to the metals like tin (Sn) or copper (Cu). Due to the thermo-mechanical loading in service of the product, these brittle IMCs shows cracks/defects and eventually lead failure. But the optimized temperature profile provides the better mechanical and thermal stability of IMCs. In standard electronics, only thin layers of IMCs are realized as good solder connections because thick growth of IMCs leads to faster crack propagation in layer and failure of electrical connection. On the other hand, for high-temperature applications (e.g. power electronics), to avoid the problems with low-melting Sn-Cu based solders, one reliable solution is to transform the solder layer (Sn) between the chip and substrate (e.g. direct copper bonded (DCB)) is to be transformed into IMCs as they have better mechanical properties as well as thermal stability. But in practice the complete transformation of solder layer into IMCs take more time. It also depends on the dimension of solder (Sn) and substrate (Cu) material. If Sn thickness is so thin, formation of IMCs take less time because the diffusion is faster. When the thickness of Sn increases, the formation of IMCs take more time. An overview of IMCs formation in tin based Sn-Cu Transient liquid phase (TLP) soldering joints have been studied in this article and discussed its importance in Power Electronic applications as a reliable interconnection technology.