Generation of Periodic Micro- and Nano-structures by Parameter-Controlled Three-beam Laser Interference Technique

摘要

Periodic micro and nano structures are required for a variety of different products in micro optics, semiconductors and products with functional surfaces. Today the common approach is standard lithography with numerous processing steps including masking imaging, resist development and subsequent etching. Laser interference structuring is an appropriate solution to provide a manufacturing technology which is able to process polymers as well as semiconductors and metals in a single processing step without any subsequent etching. Based on the theory of inter- ference superposition, the influence of different parameters is theoretically expressed and simulated. In this paper the influence of the phase and the polarization of the interfering beams upon the inten- sity distribution of the electrical fields of the three-beams are theoretically analyzed and experimen- tally demonstrated. It is demonstrated that in case of coplanar three-beam interference, the phase of the interfering beams has strong influence upon the intensity patterns of the interfering field. How- ever, in case of non coplanar three-beam interference, the phase of the interfering beams has no in- fluence upon the intensity patterns it just causes a lateral motion of the intensity pattern. By control- ling the polarization arrangements of the laser beams, different intensity patterns, like circular holes, circular bumps or rectangular bumps can be generated. The demonstrated experiments about struc- turing on positive photoresist ma-P 1275 by laser ablation verify the simulated prediction very well.