Temperature dependent effective process blur and its impact on exposure latitude and lithographic targets using e-beam simulation and proximity effect correction

Abstract

Articles you may be interested inEfficient proximity effect correction method based on multivariate adaptive regression splines for grayscale ebeam lithography Proximity effect correction using pattern shape modification and area density map for electron-beam projection lithography J.Dose, shape, and hybrid modifications for PYRAMID in electron beam proximity effect correction It is well known that cold development yields higher contrast and improved exposure latitude particularly for ZEP520 from Zeon Chemicals. In this paper, the authors quantify the effective process blur as a function of temperature. The effective process blur for our development process conditions were found to be 10, 42, and 71 nm for developer temperatures at À12, 21, and 30 C, respectively. Knowledge of how to tune the process blur can be used in a unique application. Instead of using the best possible process blur, exposure latitude is traded for improved exposure time. Optimizing the e-beam exposure time is always desired while maintaining a target critical dimension and desired shape at the wafer. In particular, the exposure time can be dominated by shape overhead delays stemming from the over digitization of curved shapes within a pattern. As such, it is better to expose a pattern with the least number of shapes as possible while obtaining the desired shape at the wafer. The authors demonstrate how e-beam simulation can be used to determine the optimal effective process blur to obtain a target desired shape while minimizing the fractured shape count to ultimately reduce overall exposure time.

A Review of Proximity Effect Correction in Electron-beam Lithography

“…It is well known that the proximity effect can be reduced or corrected by appropriate measures, including physical techniques and software-based techniques [18]- [126].…”

Design strategy of extreme ultraviolet resists

“…[47][48][49][50][51] Nevertheless, the sensitivity of ZEP520A is significantly higher than that of PMMA owing to the high efficiency of main-chain scission. 53) Many studies using ZEP have been carried out in terms of roughness, [54][55][56] dissolution dynamics, 57,58) development temperature, [59][60][61] thermal reflow, 62) shrinkage, 63) positive-negative inversion, 64) contrast curve improvement, 65) polydispersity, 53) molecular weight distribution, 66) and radiation-induced reactions. [67][68][69][70] Figure 4 shows the dependence of molecular weight distribution during exposure to EB on the initial molecular weight distribution.…”

Measurement of fogging electrons present in scanning electron microscope specimen chamber

“…The deformation of the image at this time is different from the influence of the proximity effect, which is often a problem in EB lithography. [20][21][22][23][24][25] The energetic electrons that affect the proximity effect are given by the product of the BSE yield of the specimen and the BSE yield of the objective lens, and their density is lower at the specimen surface. The energy of FGE is much lower than the energy of EB, and rather contains many SE of several eV.…”