Materials Choices for Sub-45nm Lithography: Immersion Characteristics of Silicon-Based Bilayer Resist

Abstract

Fundamental immersion characteristics such as surface properties and leaching are reported for silicon-based materials. Incorporation of as little as 8% of silicon significantly increases film contact angle compared to single layer materials. Silicon-based materials show sufficiently high film pull velocity compared to non-silicon-based films. A side-chain siloxane-based bilayer did not show any detectable silicon-leaching. The resist meets the ASML specification of PAG leaching rates being below 1.6E-12 mol/cm²-s. No silicon-outgassing was observed upon 193 nm exposure. A bilayer resist, TIS 193IL-PH (B50) demonstrated capability to resolve 65 nm dense line-space patterns with sufficient process latitudes and LER below 3 nm.