Kazunaga Sakai

New halogen-free laminate for advanced package substrate

Nowadays, the demand for the printed wiring board (PWB) of the environment harmony type is rising rapidly. We have developed a new halogen-free material with low coefficients of thermal expansion (CTE), which will be applied to the plastic packages such as FC-BGA and CSP. The original resin system and filler treatment technique named FICS (filler interphase control system) were applied to the material. The newly developed halogen-free material named MCL-E-679FG(S) has a higher glass transition temperature (Tg), peel strength, and heat resistance than the conventional halogen-free materials. Their properties are advantageous to the melting temperature rise of the lead-free solder. Another newly developed halogen-free material named MCL-E-679GT has the lower CTE combined with standard glass fabric (E-glass). It has been developed by new resin system. Its advantage is to reduce of PKG warpage, such as package on package (PoP), during the heat process for the chip mounting. In order to meet fine-line formation, we developed profile-free copper foil. With the copper foil of 18 mum thickness, we have formed the fine line of 60 mum or less pitch by the conventional subtractive method. It will be effective for advanced package substrate such as high density CSP.