Dan Maydan

High speed replication of submicron features on large areas by X-ray lithography

To achieve the high throughput necessary for a practical X-ray lithographic system, we have devised a new overall approach to X-ray lithography based on the use of X-rays with wavelengths of 4-6 Å rather than the 8.34-Å wavelength used in previous work. The principal advantage of the shorter wavelengths is that they allow a system to have X-ray windows so that large area patterns can be replicated under ambient conditions. In addition, the shorter wavelengths simplify the selection of mask substrate materials; thus we have developed a new X-ray mask structure using an optically transparent Mylar substrate. This permits realignment to be done by optical means. We also report results obtained with a new negative resist with high sensitivity to the shorter wavelength X-rays. We have achieved the replication of submicron size features using a 4.6-Å rhodium X-ray source, a Mylar mask with 7000-Å thick gold patterns, and the new resist, and have demonstrated the practicality of this system by the fabrication of propagating magnetic bubble structures with small features.

X-ray lithography

Publisher Summary This chapter presents the growth and development of the present day x-ray lithography printing methods, mostly from a process and user viewpoint. The x-ray printing method is defined and described as a system in terms of source, mask, aligner, and resist. The important component design error budget factors are detailed to provide both insight and clarity regarding the x-ray system complexity. The strengths and weaknesses of the major x-ray printing system sources and aligners are cited. Some emphasis is then given to mask technology in terms of fabrication, membrane and absorber materials, and absorber patterning. The extent of IC device damage from x-ray lithography process steps is also presented.

High speed replication of sub-micron features on large areas by X-ray lithography

We have developed, and describe herein, a new approach to X-ray lithography based on the use of X-rays with wavelengths of 4–6 A rather than the 8–34 A wavelength used in previous work. The principal advantage of the shorter wavelengths is that they allow the exposure system to have X-ray windows for increased throughput. We have achieved the replication of submicron size features in metal films using a 4.6 A Rh L α source, a new X-ray mask and new X-ray resist with high sensitivity to the shorter wavelengths and improved ion milling techniques.