Model-based optical proximity correction for talbot lithography considering the non-paraxial Talbot effect

Extreme ultraviolet lithography (EUVL) has been the leading solution for high-volume manufacturing (HVM) of state-ofthe-art integration circuits (ICs) since the first adoption in the foundry 7 nm node. However, the humongous cost of complex optical systems and power consumption make it only affordable for limited cutting-edge products. Talbot lithography, as a potential alternative utilizing the self-image of the Talbot effect, has the capability of patterning considerably large areas of periodic structures with arbitrary patterns. Since Talbot lithography is a diffraction-limited process, high resolution is achievable by adapting a short wavelength of coherent light source (13.5 nm wavelength or beyond) with an adequate design of transmission mask. Also, the interference characteristic of Talbot lithography eliminates the need for complex EUV reflective optical systems, which substantially reduces the complexity and cost of the process. Recent research has indicated the potential of Talbot lithography for application in high-resolution periodic pattern fabrication, such as advanced optical nanostructures, memory devices, and magnetic media. However, as the required pitch of periodic structures continues to shrink in advanced nodes, the assumption for paraxial approximation on the Talbot effect might be unsatisfied, which will cause a shift of the optimized patterning plane and distort the result of Talbot lithography. Besides, the unignorable proximity effects in the fine pitch of periodic patterns can further deteriorate the pattern fidelity. Therefore, a model-based method of optical proximity correction for Talbot lithography considering the non-paraxial effect is proposed in this work to improve the resolution and pattern fidelity of Talbot lithography utilizing EUV sources for the fabrication of advanced periodic patterns. Preliminary results imply the effectiveness of the proposed method in several patterns, including the layout in ASAP7.