<title>New silicon-containing negative resist for bilayer lithography</title>

Abstract

The increasing use of high density integrated circuits has created a need for development of new resist materials and lithographic schemes involving process simplification in semiconductor device fabrication to lower defect levels and improve product reliability. Towards that goal, we have developed a new negative working photoresist applicable to a bilayer resist scheme using optical and E-beam exposures. In this paper, we discuss the synthesis and lithographic applications of the silicon containing resist PHBS-AZIDE. The resist comprises a single component in which the photoactive group, an azide moiety, is chemically bonded to the base polymer, poly(4-hydroxybenzylsilsesquioxane) via an esterification reaction. The new polymer is easily synthesized and has the advantageous properties of aqueous base developability, excellent oxygen RIE resistance and high sensitivity to DUV, i-line and E-beam exposures. Sub-half micron images have been demonstrated using PHBS-AZIDE as a thin top imaging layer in a bilayer mode.