Abstract
Because of the current tendency of high density packaging, over mold packages such as PBGA and FBGA have been increasing. Their asymmetric structure causes warpage of packages, which has brought trouble in mounting process and so on. Recently, MAP type encapsulation has been developed for the small size packages of BGA/CSP, and the substrate has been getting thinner with a larger molded area. Thus molding compounds with less warpage are now strongly required. Decreasing the mold shrinkage of a compound is reported to be effective in decreasing the warpage of packages. A lower mold shrinkage can be achieved by means of getting its Tg higher and its CTE lower. But these methods can not bring a better result by its higher viscosity causing worse moldability. This report describes the development of a new molding compound with low warpage and low viscosity.
