High-resolution hexagonal array patterns fabricated by dipole cross-exposure in deep ultraviolet lithography

作     者：Dhankhar, Meena Keil, Matthias Khomtchenko, Elena Pret, Alessandro Vaglio Birkelund, Karen 

作者机构：Tech Univ Denmark DTU Nanolab Copenhagen Denmark KLA Corp Milpitas CA USA 

出 版 物：《JOURNAL OF MICRO-NANOPATTERNING MATERIALS AND METROLOGY-JM3》 (J. Micro/ Nano. Mater. Metrol.)

年 卷 期：2025年第24卷第1期

核心收录：

学科分类：0808[工学-电气工程] 070207[理学-光学] 07[理学] 08[工学] 0805[工学-材料科学与工程（可授工学、理学学位）] 0803[工学-光学工程] 0702[理学-物理学] 

基　　金：Semiconductor Equipment Division of Canon Europe N.V 

主　　题：deep ultraviolet lithography dipole illumination dipole cross-exposure assist feature hexagonal array 

摘      要：Background: A persistent challenge in deep ultraviolet (UV) projection lithography is to develop processes that can print patterns with higher resolution while maintaining acceptable control of their critical dimensions. Aim: We have improved the resolution of hexagonal array patterns using a combination comprising dipole illumination, cross patterning, triple exposure, and assist lines. Approach: Off-axis dipole illumination, achieved by self-constructed dipole apertures, is used together with a triple cross-exposure technique to produce small pitch patterns of varying sizes. We use a 248-nm wavelength KrF DUV stepper to expose mask patterns comprising arrays of quadratic structures crossed by assisted lines to print patterns with a minimum pitch size of 320 nm. The pattern optimization was accompanied by lithographic simulation calculations optimizing both the aerial image and the resist pattern after development. Results: By varying the pattern dimensions on the mask, process control can be improved, which produces robust patterns with a minimum pillar size of approximate to 95 nm both for 320- and 340-nm pitch sizes. Changing the mask polarity delivers holes with similar dimensions, whereas off-axis dipole illumination along with double cross exposure can fabricate quasi-elliptical structures with different sizes and angles. In all cases, the size of pillars, holes, and quasi-elliptical structures can be altered by changing the size of the square and/or assist line on the mask. Conclusion: We have applied resolution enhancement techniques that apply to any kind of projection lithography system. (c) 2025 Society of Photo-Optical Instrumentation Engineers (SPIE)