UV lithography

FIGURE 15.4 SEM images of vertically aligned MWNTs at (left) UV lithography and at (right) e-beam patterned Ni spots. (Reprinted with permission from [45]. Copyright (2003) American Chemical Society.)... 

Dumon, P. Bogaerts, W. Wiaux, V. Wouters, J. Beckx, S. van Campenhout, J. Taillaert, D. Luyssaert, B. Bienstman, P. van Thourhout, D. Baets, R. Low loss SOI photonic wires and ring resonators fabricated with deep UV lithography, IEEE Photonic Technol. Lett. 2004, 16, 1328 1330... 

The object of this study is to develop new photoresists for deep-UV lithography, by using the reversible photoreaction of pyrimidine bases (17-19). Applicability of pyrimidine containing polymers to both negative and positive type photoresists is due to this photoreversible reaction in which cyclobutane dimers are either formed or cleaved depending on the exposure wavelength (Scheme 2). 

However, again this application did not succeed. Optical lithography continues. First by steppers with half or third spacing. Now, a new form of lithography is close to implementation, known as extreme-UV lithography. This uses coherent UV from a plasma of Sn4+ ions, which emits at around 100 eV. 

P. Dumon, W. Bogaerts, V. Wiaux, J. Wouters, S. Beckx, J. van Campenhout, D. Taillaert, B. Luyssaert, P. Bientniau, D. van Thourhout, and R. Baets, "Low loss photonic wires and ring resonators fabricated with deep UV lithography," IEEE Phot. Technol. Lett. 16, 1328-1330 (2004). 

A major consequence of these considerations is that new exposure sources and/or very sensitive resist materials must be developed in order to realize the resolution enhancement offered by deep-UV lithography without the penalty of extremely long exposure times. Considerable advances have been made on both fronts. 

Deep-W Lithography. The important issues for deep-UV lithography (200-250 nm) are aligner optics and resist materials. Problems in aligner optics stem from the decreased transparency of standard lens materials in this frequency range, which necessitates the use of more-expensive construction materials such as quartz. Typical near-UV positive resists are not useful for deep-UV lithography because of unacceptable absorption at... 

---