Gerald A. Coquin

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.

PIEZOELECTRIC PROPERTIES OF Ba2 NaNb5 O15

Single‐crystal Ba2NaNb5O15 (z plate) has been found to have a piezoelectric coupling factor in the thickness longitudinal mode kt equal to 0.57. As a value of kt determined by direct measurement, this result is the highest value yet reported for a single‐crystal ferroelectric material usable at and above room temperature. Since this material has good mechanical handling characteristics, a relatively low dielectric constant (e33S/e0 = 30), and a pure mode of vibration, plates of this material are attractive for applications as high‐frequency longitudinal mode transducers. The approximate values of the thickness shear mode coupling factors for x and y plates are k15 = 0.20 and k24 = 0.20.

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.