High-resolution Cardo polymer dielectric "VPA-series"

Nippon Steel Chemical Co., Ltd. has developed a "Cardo" structure polymer based dielectric VPA-series. "Cardo" structure is characterized as bulky substituents attached to the sp3 carbon in polymer backbone. We achieved excellent heat resistance as an acrylic polymer by adopting fluorene as bulky substituent. We have designed a photoimageable dielectric using this polymer. This dielectric has excellent resolution (via-hole opening aspect ratio >1 for a wide thickness range) and high reliability together with heat resistance. This paper introduces characteristics of the polymer itself and featured as dielectric for both printed wiring board (PWB) and wafer level package (WLP) applications. Varnish type and dry film resist (DFR) types are available.