Study of the spatial resolution of a new 3D microfabrication process: the microstereophotolithography using a dynamic mask-generator technique

In order to manufacture new micromechanical components, a new 3D microfabrication technique called the 'microstereophotolithography using a dynamic mask-generator' process has been developed. This technique is based on the use of a liquid crystal display as dynamic mask-generator. It obliged us to choose photopolymerizable chemical mixtures, specifically designed for microfabrication, that react to visible wavelengths. The chemical resin we used showed a main disadvantage. It contains an organic dye that undergoes photochemical bleaching. A precise control of the spatial resolution of the physico-chemical processes happening during the photoreaction is required in order to manufacture small components. Then, the influence of photobleaching on the photopolymerization resolution has thus been investigated. An experimental study has been compared with a mathematical model describing the phenomenon and allowed to optimize the operating conditions of the microstereophotolithography device we built, and to manufacture small three-dimensional objects made of a large number of complex layers with a resolution better than 5 mu m. (C) 1997 Elsevier Science S.A.