Material and process effects on line-edge-roughness of photoresists probed with a fast stochastic lithography simulator

Abstract

Stochastic simulation of photoresist line-edge roughness ͑LER͒ is attempted using a three dimensional ͑3D͒ lithography simulator incorporating a fast dissolution algorithm based on a modified critical ionization model. The fast 3D simulation permits detailed evaluation of the material and process effects on LER. In this article the effects of deprotection fraction, critical ionization fraction, photoacid generator concentration, acid diffusion range, and polymerization length on LER are investigated through simulation. It is found that the relation of LER to photoresist polymerization length is greatly affected by the photoacid concentration and diffusion range.

A review of line edge roughness and surface nanotexture resulting from patterning processes

“…Our results show that line edge roughness increases with the molecular weight of the photoresist, both for classical and chemically amplified photoresists [32,59,60] (see Fig. 4a).…”

“…They also show that chemical amplification leads to higher LER compared to conventional photoresists. However, if one is careful to minimize diffusion lengths and increase the photoacid generator content in the photoresist, chemical amplification can lead to LWR that is as small as the LWR of non-chemically amplified photoresists [59,60]. The fact that LWR is reduced with reducing molecular weight points out to the need of developing molecular photoresists.…”

Stochastic simulation studies of molecular resists

“…Therefore, the influence of resist molecular weight as well as its architecture becomes important in these lithographic scales [1][2][3][4][5].…”

“…Experiments [6][7][8][9][10][11] and simulations [3][4][5], have shown that low molecular weight resist materials could result in low line-edge roughness (LER) which is a critical parameter for the next technology nodes. Fig.…”

Molecular Dynamics Study of Line Edge Roughness and the Proximity Effect in Electron Beam Lithography

“…As a solution to this problem, stochastic simulations include the polymer molecule chain to model the resist structure and the lithography process [10][11][12][13][14]. Stochastic simulations reveal the microscopic material and process effects on pattern formation in photolithography, extreme ultraviolet lithography, and electron beam lithography (EBL).…”