基于准分子激光工艺制作X射线光掩膜

X-Ray Photomask Fabricated by Excimer Laser Process

LIGA工艺是一项能够应用于制造三维微机械结构的微细加工技术,但制作掩膜版工艺复杂、成本高。为了解决商用的微光学系统制造成本问题,在Au薄膜上用准分子激光直写的方法制作掩膜,这样既能够很快得到雏形,同时也能够降低制作的掩膜版的成本。分析讨论了基于电子束制作掩膜版和基于准分子激光制作掩膜版两种方法,得出了准分子激光制作的掩膜在成本和时间上都有优势的结论。将通过准分子激光技术制作的掩膜置于X射线下,在PMMA基板上可以加工很好的三维微结构。通过依次直接激光烧蚀金薄膜可以加工具有一系列微球状结构的吸收体图形,再将此图形转写到PMMA基板上,可以得到的最低像素为25μm。

LIGA process technique is a 3D micromachining technology applied to the fabrication of 3D micmmechanieal parts, but mask process is a complex technique with high cost. In order to reduce the cost in commercial applications （as sensors or in telecommunication） of micro optical systems, direct laser patterning of absorber （Au） thin films of LIGA mask allows the possibility of rapid prototyping and low cost manufacture of X-ray lithography mask. Two methods of EB lithography and excimer laser lithography are analyzed, the latter has two advantages in process cost and period. When put the fabricated LIGA mask under the X-ray, perfect microstructure in the polymethyl methacrylate （PMMA） substrate can be obtained. The patterns with circle structures with 25 μm pitch can be fabricated by sequential direct laser ablation of thin Au film using mask projection techniques.