Integrated non-SO ₂ underlayer and improved line-edge-roughness dielectric etch process using 193 nm bilayer resist

We present an integrated reactive ion etch (RIE) process using bilayer (a top imaging layer and a bottom underlayer) thin film imaging system to push the limits of 193 nm wavelength photolithography. Minimizing the line-edge roughness (LER) and maintaining the critical dimension (CD) of the transferred pattern are important in high-resolution RIE. Along with LER and CD issues and shrinking ground rules, deleterious effects of S O2 in the underlayer etch chemistry necessitated the development of non- S O2 chemistry. Thus a N2 - H2 -CO chemistry was developed and integrated with the etch process of underlying borophosphosilicate glass using Ar- O2 - C4 F8 -CO-C H3 F chemistry. © 2006 American Institute of Physics.