Effect of design on the replication of micro/nano scale features by micro injection moulding

The replication of micro/nano scale features is of great interest for MEMS and Microsystems. However, the flow behaviour of melts into a micro/nano cavity is still not well understood. In this work, we used the micro injection moulding process to replicate micro/nano scale channels and ridges from a Bulk Metallic Glass (BMG) cavity insert. High density polyethylene (HDPE) was used as the moulding material. The influence of feature configuration, length, width, gap distance between features, location on substrate, and substrate thickness on the quality of replication was investigated. The experiments revealed that the replication of ridges, including feature edge, profile and filling distance, was sensitive to the flow direction; a critical feature length was found below which the filling of features was significantly reduced. Both the feature location and the substrate thickness had an influence on the filling of micro/nano features while the gap distance had a negligible effect on the replication of features.