Integration of Thin Film Polyimide with PCB Technology

The development of high density packaging technologies offers cost reduction, smaller system volumes and better performance. High performance PCBs with fine line technology reach conductor widths of <0.1 mm and pitches of <0.2 mm. The limiting factors for higher densities of PCBs are the mechanically drilled through‐holes. In particular, the assembly of modern ICs with a pitch of less than 0.2 mm requires fine line technology and a simultaneous reduction of via diameters to minimise fan‐out areas. To meet these requirements, an interconnection system with photosensitive polyimide as an interdielectric thin film layer on top of a PCB is investigated. To demonstrate process feasibility, a test module including a test structure for measurement of contact resistance has been fabricated.