193nm lithography: New challenges, new worries

Photolithography has now moved forward to such an extent that we are considering imaging the 130nn and 100nm technology nodes with optical systems, unthinkable a handful of years ago. To do this we have been using the biggest control knob we know, wavelength. The latest wavelength to be introduced into production will be 193nn which will arrive with full field scanners this year. To image using 193nm we have had to radically change the polymer systems we use due to high absorption with conventional chemistries This has led to materials that will be the most difficult to integrate into manufacturing that we have ever faced. The primary challenge we encounter is the high resist thickness loss in the pattern transfer steps. This is primarily due to low etch resistance of the materials in use but we will also show that photochemical deprotection of the resist during etch has a contribution. One approach to overcome this is to use significantly thicker resist films, this leads to its own problems with pattern collapse a major worry which could easily become a limiting factor in this technique.