High density MLB using additive and build-up process

A new type of printed circuit board with high density MLB (Multi-Layered printe circuit Board) has been developed for requirement of high density routing and high reliability substrates as LSI packages. The new technology has enough photo-resolution capability of Line/Space = 35μm / 35μm and 80μm diameter via hole. A full additive method is applied for the patterning, to attain the multi-layer structure. Used insulator is an unique, and newly developed photo-imagable dielectric resin which has a glass transition ≃ 200°C, peel strength ≃ 1.2kg/cm, and withstands 1000 cycles of thermal cycling (TCB). The insulator is composed of high heat resistant photo-sensitive epoxy and supper engineering plastic. This technology is suitable for direct chip attachment. This paper describes the characteristics of the new MLB.