Fabrication of a large-scale Ni stamp using a multi-level SU-8 photoresist mold for advanced printed circuit board manufacturing

Recently, as integration density of electrical devices has increased, multi-layered, fine-patterned printed circuit board (PCB) technology has been advancing. As a high-volume, low-cost manufacturing method, PCB fabrication by imprinting has gained much attention. A large-sized Ni stamp plays a critical role in this method. We thus developed a novel fabrication method for a large-sized multi-level Ni stamp, which imprints patterns directly onto PCB resin, using multi-level patterning of an SU-8 photoresist. In this study, we focused on two aspects: (i) the property of SU-8 adhering to a large-sized glass substrate and (ii) neat and complete removal of SU-8 from the Ni stamp using a self-assembled monolayer. Using the processes we developed which will be described in detail in this paper, we successfully demonstrated a multi-level Ni stamp as large as 190 mm x 190 mm in size. The actual imprinting test exhibited successful results showing suitability of the developed method for large-scale, low-cost and high-volume manufacturing of the advanced PCBs.