Process Issues in Bilayer and Dry Lithographic Techniques

The shift from aqueous base development to the dry development employing oxygen plasma is rather drastic and therefore many issues must be addressed before implementation of the new technology in manufacturing. First of all, a new equipment (etcher) is needed and the etch uniformity (across a wafer and wafer-to-wafer) is a very important issue from a tooling point of view. The all-dry TSI technique requires a silylation equipment as an additional tool set. 

While the bilayer lithography can improve the process margin and therefore yield without introducing a new exposure tool, the most serious potential problem is the resist LER after 02 RIE, which is likely to be more devastating as the feature size moves toward 50 nm. 

---