Etch Selectivity of 4SiMA:Hydroxystyrene Based Copolymers. Silicon Chemistry for Bilayer Resist Systems

Thin film imaging resists (TSI and Bilayer systems) confine the imaging to a thin resist film (in the case of a bilayer system) which is subsequently transferred to a thicker polymeric underlayer. This approach has a number of potential advantages including increased ability to print high aspect ratios at small feature sizes, better resolution at a given depth of focus (DQF), and minimization of resist substrate interactions including resist "footing, " standing wave formation and reflective notching caused by topography. Continued progress in single layer resist technology has been able to meet the current manufacturing requirements and the more complex TSI approaches have not yet been required. However, the requirements for imaging features below 0.18 microns, the desire to extend high NA 248nm exposure technology and anticipated shift to 193nm exposure tools has led to renewed interest in thin film imaging approaches. In this report we will describe new chemistry developed for bi layer resist systems for use at 248 nm in both positive and negative tone.