Effect of high-frequency variation on ArF photoresist deformation during superimposed dual frequency (DFS) capacitively coupled plasma etching

As the degree of device integration increases in the fabrication of Si semiconductor devices, a scanner with shorter wavelength is needed to increase the resolution of photolithography. However, the photo-resist (PR) for a shorter wavelength has to be thinner and softer because the shorter wavelength has a higher opacity and lower depth of focus. With the introduction of 193 nm ArF PR for the dielectric etch process including silicon nitride hard-mask opening in sub90 nm device node and beyond, plasma etching process development using ArF PR becomes very important due to its poor plasma etching resistance.