High resolution thermoplastic rapid manufacturing using injection moulding with SU-8 based silicon tools

The present work focuses on developing cost-efficient, fast and precise tooling for prototyping and small-series manufacture of polymer chips using injection moulding. Exchangeable mould inserts were manufactured on thick silicon wafers patterned using SU-8 negative epoxy-based resist. First masters with feature size from a few tens to hundreds of micrometers were produced in SU-8 photoresist by contact photolithography. Polypropylene (PP), cyclo-olefin-co-polymer (COC) and polymethylmethacrylate (PMMA) were used as the injection moulding materials. A study of the PP parts was carried out using scanning mechanical microscopy (SMM) and scanning electron microscopy (SEM). In addition, submicronic features (500 nm) were replicated in PP from a tool patterned by e-beam lithography.