Downscaling of integrated circuit has been approaching the limitation in recent years, and the price-performance ratio is also gradually not in line with the benefits. Therefore, the industry has brought up the solution of “Chiplets” to continue corresponding to Moore's Law, even “More than Moore”. Over the years, both major packaging factories and even IC manufacturers have invested a lot of resources in the research and development of IC packaging technology for Chiplets. 2.5D IC is currently the most used package for Chiplets. Compared with 2.5D IC, the development of FOCoS uses a relatively simple fan out RDL process, which also meets the package design requirements of most Chiplets and heterogeneous integration designs. Due to the cost advantage, FOCoS gradually attracts the attention of IC designers; in addition, the FOCoS-B technology, a new type of packaging is now developed based on the respective advantages of both 2.5D IC and FOCoS. It will be a star of tomorrow in the field of Chiplets package and heterogeneous integration design in the near future. In this paper, the package technology 2.5DIC, FOCoS and FOCoS-B will be discussed. And the analysis and comparison of various design aspects including layout capability, electrical performance, stress and thermal characteristic etc. will be performed.