Plasma-Developable Photoresists

In 1979, Smith and co-workers described the development of a system they called PDF (which presumably stands for Plasma Developable Photoresist) that is based on the use of a material, the structure of which has not yet been divulged 61). In this process the resist is coated in the usual fashion and exposed optically. The exposed film is then subjected to a baking cycle that produces a relief image of negative-tone that is, depressions are generated in unexposed areas (Figure 45). This relief structure is... 

Yokota, A. Yabuta M. Kanai, W. Kakhiwaga, K. Hijikata, I. Nakane, H. "Plasma Developable Photoresist Containing Electronic Excitation Energy Quenching System," SPE Regional Technical Conference, Ellenville, New York, Nov. 1982. 

Figure 3.31. A schematic representation of the plasma-developable photoresist...

MacDonald, S.A. Schlosser, H. Ito, H. Clecak, N. Willson, C.G. Plasma developable photoresist systems based on chemical amplification. Chem. Mater. 1991, 3, 435-442. 

L First manufacturing use of chemically amplified resists Plasma-developed resist first described X-ray proximity lithography demonstrated Bis-azide rubber resists introduced DNO-novolac resist for microelectronics introduced Photoresist technology first applied to transistor fabrication DNO-novolac resist patented by Kalle... 

The chemical amplification idea appeared when it was necessary to develop photoresist material having high sensitivity, high resolution, and good plasma etch resistance. It was desirable primarily when the 248 nm exposure became the requirement of the industry. And the result of implementation of the idea was very good. Chemical amplification as a basic ideology of the photoresist creation partly worked at the 193 nm millstone. ... 

After developing, the substrate is subjected to a hard-baking process to harden the photoresist. The hardening of the photoresist is done as the patterned substrates may be used for further processing such as plasma etching or ion implantation. Once all the processing is complete, any remaining/developed photoresist can be removed... 

The pursuit of further miniaturization of electronic circuits has made submicrometer resolution Hthography a cmcial element in future computer engineering. LB films have long been considered potential candidates for resist appHcations, because conventional spin-coated photoresist materials have large pinhole densities and variations of thickness. In contrast, LB films are two-dimensional, layered, crystalline soHds that provide high control of film thickness and are impermeable to plasma down to a thickness of 40 nm (46). The electron beam polymerization of CO-tricosenoic acid monolayers has been mentioned. Another monomeric amphiphile used in an attempt to develop electron-beam-resist materials is a-octadecylacryUc acid (8). 

---