High performance photo-sensitive insulating materials for high density multi-layer wiring boards

Abstract

The photo-via build-up process is a most significant candidate for fabrication of high density multi-layer wiring boards for high density packaging using CSP and flip-chip direct attach. We have developed a new type of photo-sensitive dielectric. The dielectric delivers high resolution in fabrication of photoformed microvia holes with an aspect ratio of 1.0. The photo-sensitive dielectric showed excellent electrical and mechanical properties for surface mounted wiring boards. It also shows outstanding mechanical properties, especially in the high temperature region. Excellent insulating properties and adhesion were proven, even after pressure cooker test (PCT) conditions. These features offer a great advantage in achieving higher interconnect reliability in direct-chip attachment on low cost multichip modules using sequential build-up substrates.