This paper highlights the latest results from ongoing 193nm thin film imaging (TFI) programs, as well as some recent results from the MicroChem Corp. 193 TSI program
1. Recently, top surface imaging strategies have been augmented with bilayer
2-4 imaging approaches employing silicon-based materials either liquid or vapor deposited over thick phenolic polymer matrices. These newer approaches have been investigated in part because of poor photosensitivity, low silylation contrast, unacceptable line edge roughness (LER) and process performance reliability issues associated with present TSI techniques
7.Chemically amplified approaches, while providing acceptable photosensitivity, have also shown increased LER relative to non-chemically amplified single component resists
7. While silylation contrast has been implicated in LER, it was found in one study
8 that all TFI approaches, even trilayer processes using near-ideal SiO
2 masking, gives some process induced LER. Consequently, LER is thought to result from a variety of mechanisms, depending on the TFI process employed, and that specific process optimization is needed to minimize LER magnitude
8. MCC offers a simple, non-chemically amplified TSI approach with NANO
TM MX-P7, a single component photoresist giving etched wall profiles generally superior in edge smoothness to those produced from chemically amplified TFI techniques. Although this PHS-based resist has demonstrated the best LER performance for TSI thus far, its photosensitivity is -5-10 fold slower than desired. In an effort to understand and correct this deficiency, and as part of our ongoing work
1, we have continued to characterize substituent effects for varying chemical functionality appended to PHS. Results reported here, for three such modified PHS derivatives using standard vapor phase silylation conditions, show 3-4 fold photosensitivity improvements when compared with similarly processed reference MX-P7 resist. Thin film imaging, and TSI in particular, was also highlighted as a route to successful 157nm and EUV imaging, in a variety of papers
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