Resist blur and line edge roughness

Abstract

A straightforward analytic model of resist line edge roughness is presented which predicts all the known scaling laws as well as the shape of the experimentally seen frequency content or power spectrum of the roughness. The model implies there are strong basic limitations to achieving, simultaneously, low roughness, low dose and high resolution in any standard chemically amplified resist process. A simple model of how roughness maps to device performance is also presented.

EUV Resists: Illuminating the Challenges

“…For the results presented below, we use the numeric implementation [8] of the analytic stochastic model first described in Ref. 7. Figure 2 shows the modeled photons noise limited LER as a function of sensitivity along with the data from Table 1.…”

“…In this section we consider the potential role of photon noise in the data shown in Table 1. To study this problem, a variety of shot noise models have been developed [7][8][9][10]. For the results presented below, we use the numeric implementation [8] of the analytic stochastic model first described in Ref.…”

EUV Resists: Pushing to the Extreme

“…To assess the status of the photon limit we use the stochastic Multivariate Poisson Propagation Model (MPPM) [10][11][12]. Starting with the known aerial image, resist absorptivity of approximately 0.004 nm -1 , 30 nm film thickness and an assumed acid blur as determined from the measured LWR correlation length, we determine the photon-noise limited line-width roughness (LWR) as shown in row two of Table 2.…”

EUV Extendibility: Challenges Facing EUV at 1x and beyond

“…Based on the known aerial image, resist absorptivity of approximately 0.004 nm -1 , the 30 nm film thickness and an assumed acid blur as determined from the measured LWR correlation length of 11 nm, one can use stochastic modeling [6][7][8] to predict the photon-noise limited LWR. For Resist A we predict a shot-noise limited LWR of 1.76±0.05 nm and 2.12±0.04 nm for Resist B.…”