Study On Laser Interferometric Lithography Technology Based On Multi-beam Interference

Utilizing photic -interference and diffraction, laser interferometric lithography can control the distribution of light intensity within interference field by certain combination of beam. And we can get lithographs when this distribution results are recorded by sensitive materials. Since expensive optics projection system is not necessary and the area of exposal field is only limit to transit aperture of system, laser interferometric lithography has become a burgeoning and low-cost lithographic method. It is especially fit for the production of microelectronic and photo electronic elements'periodic structure graphs, such as field emission electrode of large screen panel display, CCDS based on silicon and even DRAM cells etc. Laser interferometric lithography is a promising method which make up for existing photics lithography.Based on the theory of laser maskless interferometric lithography, the paper first describes simulation program and carries on a research on laser maskless interferometric lithography using computer simulation. Through above work, we get the light intensity cubic graphs and two dimensions contour map of double-beam, three-beam and four-beam and the simulation results show that double-beam interferometric lithography can creates stripe structure, three-beam interferometric lithography creates triangle lattice, while four-beam interferometric lithography creates cubic lattice. Then we separately design and build double-beam interference, three-beam interference and four-beam interference lightcircuits and apply them to positive and negative photoresist to carry on our research. After exposal and develop, we use optics microscope and scanning electron microscope to record the interference graphs, and the results totally accord with the simulation results.In addition, film abruption technology takes very important application part in the field of biology pharmacy, water quality management and environmental engineering. Nowadays, the fabrication arts and crafts of metal filtration film mainly are metal powder sinter, sol-gel, electro analysis deposition and CVD etc. However the films which are prepared by using these methods has some ubiquitous problems, such as high brittleness, irregular distribution of film holes and big size decentralization of film holes etc. Moreover, along with the process of fabrication there are severe environment pollution, large energy consume which has bad effect on human health and entironment. Therefore, it's important to develop a new method. Laser technology can support a new way for fabricating metal filtration film in fine machining field.Considered all of above, in order to fleetly fabricate metal filtration film with large area and high performance, we attempt to apply our three light circuits to silver and aluminum film to discuss the feasibility of using ns laser interference beam to fabricate metal filtration film. The results display that the aperture of silver and aluminum filtration film and the edge of hole is uneven. The former research shows that the time scale between fleetness electrons cooling and energy transfer to crystal lattice is ps level. If the laser pulse is fs level, i.e. the time scale betweenfleetness electrons cooling and energy transfer to crystal lattice is very short, and the process of ablation can be considered as direct transfer from solid to gas (or from solid to plasma). While in our research, ns laser pulse is used to ablate, there is enough time for heat transfer to target which results in the appearance of liquid. In this case, materials will wipe off at the condition of co-existence of gas and liquid. In the end, the counterforce which is produced by evaporation can push liquid and bring on uneven aperture holes.From the simulation and experiment we know that laser maskless interferometric lithography has many advantages, such as large visual field, high resolution, comparative simple system, low cost and convenience to realize. In our paper, we design and build multi-beam interference technology to explore the fabrication arts and crafts of metal filtration film. This technology has deep potential on fabrication of metal filtration film, so it's necessary to carry on further research.