PMMA

Polymethl methacrylate (PMMA), also known as acrylic is a transparent thermoplastic often used as a resist mask in e beam lithography.

Hot embossing is an easy method for the reproduction of microstructures. Under vacuum, a moulding tool is pressed into a heated thermoplastic polymer. For subsequent electroforming of metallic structures, the residual polymer layer that inevitably remains between substrate and moulding tool has to be removed, this can be achieved by plasma processing using Inductively Coupled Plasma (ICP) or Reactive Ion Etching (RIE).