Design, fabrication of through silicon vias based on suspended photoresist thin film and its application in silicon interposer

This paper presents a novel fabrication method of through silicon vias (TSVs) based on suspended photoresist thin film. The AZ5214 photoresist thin film is self-assembled on the deionized (DI) water surface, then the film is transferred onto the wafer surface and patterned by photolithography to form the cover plates on the through-vias. After a Cu seed layer is deposited and the photoresist film is chemically removed, the through-vias are filled by Cu electroplating. The process steps, characterization and the feasibility are analyzed in our experiment. According to this approach, one of its applications in silicon interposer is provided and the processes are discussed.