As interest in fabrication methods for three dimensional (3D) structures has increased, various studies have been conducted to fabricate micro- and nano-structures. The nano-stereolithography process has been recognized as one of the most promising technologies for the fabrication of three-dimensional micro structures with submicron fabrication resolution, and to meet the demand for a process of fabrication of complex 3D micro structures. By considering the surface tension during the fabrication process, it is possible to increase both the fabrication efficiency and the success rate. In this paper, an open structure was fabricated using the 3D laser scanning method. For the fabrication of a perfectly supported open structure, the line width, according to various levels of laser power, was estimated experimentally and the fabrication window was derived with a number of experiments. Compared to the closed structure, the open structure has advantages in terms of fabrication and its functional perspective.