New Super-Low CTE (0.7 ppm/K) Core Material for Next Generation Thin CSP

The thinner and higher density PKG (package) is being required strongly for the growth of smaller mobile devices. Especially, package on package technology (PoP) has become a mainstream for application processors which are installed in smartphones and tablets. However, the warpage of thinner PKG often causes a problem at the chip mounting process. The main factor of warpage is the mismatch of CTE (coefficient of thermal expansion) between substrate and chip. Therefore, the lower CTE core materials are needed for the thinner PKG. Recently, Hitachi Chemical has developed the super-low CTE material, core and prepreg, applying our new resin system and filler treatment technology, and placed it on the market. Furthermore, a super-low CTE material of 0.7 ppm/K is currently under development. The super-low CTE material shows the best warpage performance in our low CTE core material lineups, maintaining its higher Tg, high modulus and low Dk/Df values.