Single-layer resist systems

As for negative deep UV resist, O Toole et al. have exhibited half-micron pattern resolution in 0.5 micron film thickness using the new resist and PIE process (10). The pattern profiles, however, were re-entrant, due to the large photo absorption and the applications to single-layer-resist system have not been presented (11). 

We achieved high aspect ratio sub-half-micron pattern fabrication in 1.0 micron film thickness using this new resist. We are convinced that this new resist could make possible simple and efficient single-layer-resist system for KrF excimer laser lithography. 

Fig. 4.9). In a single-layer resist system this is achieved by either a slight overexposure or a slightly longer development time. 

Almost every single-layer resist system designed for DUV 248-nm (KrF) and DUV 193-nm (ArF lithography) needs some kind of antireflection coating to mitigate... 

The impact of photoacid generator (PAG) stmcture has been largely ignored for 193-nm single layer resists due to the concentrated polymer-oriented work discussed above. Most published work to date has involved the use of triflic or metallic (antimonate or arsenate) photoacids. Many PAGs used in DUV (248 nm) resists are inefficient when formulated with (non-phenolic) polymers used in 193-nm resists, presumably due to the lack of the electron transfer sensitization pathway thought to be in use in phenolic systems (i.e., 248nm resists). 

Ding, D., Tang, T., Song, G., McDolnald, A., 2011b. Characterizing the performance of a single-layer fabric system through a heat and mass transfer model. Part 11 thermal and evaporative resistance. Text. Res. J. 81 (9), 945-958. 

Multi-level systems(l) allow the planarization of substrate topography formation of high aspect ratio patterns, and better resolution than single level resists. There is a drawback to such systems, however, and that is additional process complexity. To reduce this complexity, two-level resist systems have been reported(2). The top imaging layer in two-level resist systems must exibit Op-RIE resistance as well as desirable lithographic characteristics. 

One technique for reducing this proximity effect is to replace the single layer of resist with a multilevel resist (MLR) system. In this case, a thin radiation sensitive resist is separated from the substrate by a thick layer of organic material (1). The utility of this approach has been demonstrated experimentally in several laboratories and also investigated by various computer modeling studies. 

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