Characterization of SEM electron beam LIGA system

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 surface roughness. LIGA is already used for MEMS, micromechanics, micro-optics, micro-hydrodynamics, microbiology and in chemistry production. The authors proposed an alternative system for LIGA process: instead of using the diffusion radiation of a synchrotron, the electron beam of a SEM has been vectorially controlled in order to irradiate a specific path on the resist without using any mask. Once the EBL (Electron Beam Lithography) system was fabricated, an experimental campaign concerning several engraving tests was carried out to characterize the device performance. Aim of this work is the characterization of the system, in particular the geometrical accuracy of the engraving. In order to do this, a benchmark pattern was chosen, a set of engravings was carried out and, after development, photographs were taken by means of an optical microscope. From these data some quality parameters were finally evaluated.