ABSTRACT
Photolithography, which consists of etching locally a photosensitive polymer œlm spin-cast on a °at substrate (Figure 18.1, le§ column), is central to top-down micro-and nanofabrication methodologies. ›e image of a drawing is œrst projected on the œlm through a mask and possibly a set of lenses; subsequent development of the exposed regions, that is, removal of the exposed regions when a positive tone resist is used, results in the etching of the drawing in the polymer œlm (Rai-Choudhury 1997). ›is topographically patterned œlm then serves for further operations such as localized deposition of metals, etching of the underlying substrate, or ion implantation, which are basic processes for the fabrication of integrated circuits (IC) (Campbell 2001).
