Independent-Exposure Method in Electron-Beam Lithography

In this research, the new approach called independent-exposure method in electron beam lithography for the fabrication of micro optical elements such as a multi-level lens was suggested. To sum up, this method can significantly reduce the fabrication process, i.e., a multi-level lens can be fabricated by only one process of both lithography and etching. However, before applying this method to the fabrication of a multi-level lens, proximity effect should be considered and several preliminary experiments or consideration should be required. 1. The electron beam resist should be deposited with the thickness over that of a multilevel lens. 2. The developed resist thickness is proportional to electron beam dose. 3. The developed resist increases as the pattern size increases on identically given electron beam dose. 4. There is the interference of electron beam given to adjacent patterns. Based on the fabrication and optical results, it was evident that the independent-exposure method is suitable to fabricate a multi-level lens with non-repetitive process.