The Research Of Maskless Microscopic Lithography Micromachining With Digital Micro-mirror Device

Micromachining technology is a basic modern science and technology. It is derived from the semiconductor processing technology which based on traditional lithography, mainly used for silicon-based materials and two-dimensional structure. As the most important and successful micro-machining technology, conventional lithography technology plays a vital role in the semiconductor industry. But for non-semiconductor fields, for example biology, chemistry, medicine, conventional lithography is rarely used. Compared to conventional lithography, soft lithography as another micro-machining technology which rises from the1990s, has broader applications. Soft lithography is a kind of micro-graphics technology. It works as a seal. The micro-models could be copied on any surface.Digital micro-mirror device,(DMD) is an important projection apparatus. It is a micro-lens array made of aluminum. Based on the signals loaded each micro-mirror can be switched to+12°or-12°related to the equilibrium position. In terms of the optical path at the perpendicular position of DMD the two different angles corresponding to "ON" and "OFF" states. Therefore, the micro-mirror can be considered as the optical switch at a particular angle of light path. Changing the duty ratio of optical switches will change the intensity of emitted light of DMD. Thus, DMD can be used as a binary amplitude spatial light modulator.Microfluidic chip is a multidisciplinary field which integrates physical, chemical, biomedical and micro processing together. It is trying to achieve the miniaturization, automation, integration and portability for the processes from sample preparation to detection. Microfluidic chip has the ability to let the handling and detection of sample to be fast, efficient and precise. It is a high accuracy, low cost and high portability device. It has a huge impact on the development of chemical, biological, pharmaceutical and other fields. The research of it is important.As the key elements of lithography, the light source and the mask determine the quality and cost of micro-processed products, In order to improve the quality of the lithography light source and eliminate the dependence of the lithographic mask, laser beam shaping and maskless lithography have been explored in this paper. The diffraction effects modeling of DMD has been estimated and the simulation analysis has been done. According to the diffraction effects of DMD, a new method in fabricating the micro-lens array has been proposed.The establishment of a laser beam shaping system based on DMD has been introduced in the second chapter. By using the binary amplitude adjustment mechanism of DMD, the light intensity of the laser beam through the binary amplitude adjustment could be shaped to various kind distributions, In this paper, a super-Gaussian beam has been successfully shaped from the Gaussian beam with the utilization of DMD. This technique will be widely applied in lithography, quantum emulation and holographic optical tweezers which requires precise control of beam profile. A new gamma curve correction method has also been introduced to improve the accuracy of laser beam shaping.The third section introduces the DMD based mask-less soft lithography system. Based on the imaging and spatial modulation, a virtual digital mask could be generated and the conventional photolithographic mask of the physical entity could be replaced. Because this kind of mask is digitized, it provides a fast, convenient, inexpensive, accurate and flexible solution for the mask generation, control and modify. Meanwhile as the light intensity of the laser can be binary amplitude modulated, by changing the duty cycle of the optical switch, the intensity of exposure of the photoresist can be controlled precisely. We also have examined the diffraction effect of DMD. A DMD diffraction model has been established and simulated. Based on the diffraction effects and combined the Abbe imaging principle and spatial filtering technique, a new method of fabricating a micro-lens array has been proposed.The fourth chapter describes the relevant physical mechanisms of microfluidic. It is the preliminary groundwork of our research group in the field of microfluidic chip.At last is the summary and outlook of my work during the course of graduate school.