Thick-film photolithography based on SU-8 has gained great interest in the field of microreplication technologies. For replication applications the SU-8 structures themselves or electroplated copies of the resist structures are used as casting or embossing tools. In this paper, a simple estimation model is proposed to predict the sidewall profiles of SU-8. This model is based on the effects of Fresnel diffraction and absorption resulting in useful approximations for the pattern profile of SU-8. Its usefulness is successfully verified by experimental results; the estimated and experimental results show similar trends. In addition, by utilizing this model two exposure methods based on reflection and refraction could be developed which avoid negatively sloped sidewall profiles of SU-8. Using these exposure methods, SU-8 preforms without undercut for the replication of optical waveguides have been achieved.

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LIGA is the basic idea of promising developments for the manufacturing of microelectromechanical system parts containing high aspect ratio microstructures. Aim of the work is a brief discussion of the starting-points for inline process inspection within a direct LIGA technology using deep X-ray lithography for the production of micromechanical gear wheels with critical dimensions of similar to 35 mu m width at similar to 1 mm height as well as to show methodic and technical measuring possibilities. Firstly, results of the determination of residual solvent content distribution within ultra-thick SU-8 films are shown obtained from refracted near field optical measurements. Furthermore, the capability of X-ray computer tomographic imaging is discussed and measurements for the determination of the three-dimensional shape of high aspect ratio microstructures are practically demonstrated with microscopic and interferometric optical methods. Finally, first results demonstrate the potential of the optical coherence tomography for several further important measurement tasks, among others, e.g. for the imaging of the distribution of mechanical stress at the resist-substrate interface. The results show that much information which is essential in the LIGA process can be achieved with recently available measurement methods. However, further development of non-destructive measurement techniques would be desirable for an effective inline process control of mass production of micromechanical parts

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