Microphotofabrication of Very Small Objects: Pushing the Limits of Stereophotolithography

Stereophotolithography (SPL) allows to manufacture 3D polymer parts directly from Computer Aided Design data files. Its principle is the space resolved polymerization of a resin by a laser. We first discuss the possibilities to make parts with a very high resolution. A first approach was to push the classical SPL process to its limits to get a resolution of about 30 micrometres. A second really innovating one was to modulate the light flux by a liquid crystal display and we obtained a resolution of 5 micrometres. Since the use of these parts is limited by the nature of photopolymers, we also developed a new process to make complex polymer/metal parts directly. It consists in making the part layer by layer by using three techniques: SPL, electrodeposit of copper and laser silver plating.