LIGA process technique is a three-dimensional micromachining technology which is applied to fabricate 3D micromechanical parts. Because the LIGA process requires LIGA mask for deep-etch X-ray lithography, the mask fabrication is a complex technique. The use of micro optical systems in commercial applications (as sensors or in telecommunication) is not only depending on the performance but also on the price of the system. It is highly dominated by fabrication and assembly costs. In order to solve this problem, many efforts have been made in the world. Direct laser patterning of absorber thin films of LIGA mask allows the possibility of rapid prototyping and low cost manufacture of X-ray lithography mask. Excimer laser mask projection techniques have been used in order to directly manufacture LIGA mask for X-ray lithography. The mask pattern with circles structures with 25µm pitch have been fabricated by sequential direct laser ablation of thin gold film using mask projection techniques.
This paper describes the X-ray mask design and fabrication processes in details. The fabricated LIGA mask is used as a pattern for x-ray exposure onto a polymethyl-methacrylate (PMMA) resist. A fine micro structures of PMMA in a low cost and a short fabrication period is obtained using the mask. It is confirmed that such LIGA mask is important for rapid prototyping in the areas of medical and biosensors.