Experimental verification of sub-wavelength holographic lithography physical concept for single exposure fabrication of complex structures on planar and nonplanar surfaces

Abstract

Authors of the report have been developing Sub-Wavelength Holographic Lithography (SWHL) methods of aerial image creation for IC layer topologies for the last several years. Sub-wavelength holographic masks (SWHM) have a number of substantial advantages in comparison with the traditional masks, which are used in projection photo-microlithography. The main advantages: there is no one-to-one correspondence between mask and image elements thus the effect of local mask defects almost completely eliminated [1]; holographic mask may consist of single-tipe elements with typical size many times bigger than projection mask elements [2]; technological methods of image quality optimization can be replaced by virtual routines in the process of the holographic mask calculating, that simplifies mask manufacturing and dramatically reduces the mask cost [3]; imaging via holographic mask does not need the projection lens, that significantly simplifies photolithographic tool and reduces ones cost. Our group developed effective methods of holographic mask synthesis and of aerial images modelling and created software package. This methods and calculation results were verified and reported many times [1-3].