Study On Imaging Of Digital Lithography Technique With A DMD

The great demands for the micro-devices with micromation, lightweight and integration have vastly prompted the development of the micro fabrication technologies in information era. The MEMS and MOEMS techniques of the rapid development based on micro optics, microelectronics and micro mechanics have indicated an expansive future, which are applied in the aviation and space flight, optical communication, optical interconnected network, optical computing and other many high technique fields, and will also have a far-reaching impact on the military science and technologies, industry and the living of the people which we confront in the current century. The conventional photolithographic technology from VLSI technique exists in large limitations for the fabrication of micro optical, MEMS and MOEMS elements with three-dimension (3D) continuous structure. In this thesis, the study on lithography technique with DMD digital mask for the fabrication of 3-D arbitrarily shaped microstructures has been carried out. The system of DMD digital masks lithography is proposed and set up through the sufficient investigation. According to the characteristics of periodic microstructure of DMD, we present a partial coherent imaging model of digital mask lithography. We had studied on DMD grayscale, which is achieved by binary pulsewidth modulation of the incident light. Because each micromirror structure of DMD is the same, it is only need to give the imaging process of a single micromirror. In this analysis, object light source is regarded as combination of many incoherent light source (single mirror), while each minor is illuminated by a coherent light source, that is, the imaging process is a process of using partial coherent light. At last, the simulations have been made based on the partial coherent imaging model, and the micro-optical elements such as the micro lens have been achieved on SHSG through the applications of DMD digital mask and enzyme etching technique.When the DMD digital mask is used in the conventional photolithography , which is greatly simplified. Because the mask design can be adjusted in real time, it is comparatively easy to change the mask design to compensate any nonlineareffects in aerial imaging, in photo resist exposure, development and substrate etching processes. Thus it gives a new and effective approach for the fabrication of the continuous shaped microstructure and has very important significance to the development of micro optics and MOEMS.