A system for vector control of SEM electron beam: a new application for LIGA technique

The trend towards the downsizing of mechanical parts is increasing in many fields. The LIGA (Lithographie Galvanoformung Abformung) process is one of the most promising micromachining techniques due to its numerous advantages: extreme precision, depth of field and very low intrinsic sur-face roughness. LIGA is already used for MEMS, micromechanics, micro-optics, micro-hydrodynamics, microbiology and in chemistry production. In the traditional LIGA system a flux of X-ray photons, origi-nated by a synchrotron radiation source, passes a lithographic mask and irradiates a polymer used as photoresist. Successively, the resist is developed by wet organic chemical processing dissolving only the irradiated regions. In this work an innovative system for LIGA process, overcoming the critical aspects of X-ray technology, is proposed. The electron beam of a scansion electron microscope (SEM) has been vectorially controlled in order to irradiate a specific path on the resist without using any mask. The pre-sent work describes hardware (integrating the commercial SEM), software (generating beam paths basing on a CAD neutral file) and preliminary tests (characterizing the overall performances).