Abstract

At the present days, the key and critical part of industrial IC manufacture is the optical lithography technology which can duplicate the design patterns on the mask onto wafer by light exposure. However, when the mask patterns are too small which are approaching light wave length, the image quality and resolution on the wafer are getting worse owing to diffraction effect. Therefore, some necessary resolution enhancement techniques are proposed with remarkable skills and algorithms, and need to be verified by simulations or experimental results. The most direct and accurate simulation is the imaging of patterns on wafer. Accurate imaging simulation can show exposed and unexposed regions after photolithography by computer. Existing commercial and academic OPC simulators which compute in frequency domain with Abbe's method applied on partial coherent light source take several days for computation with hundreds of computers working together at the same time. Hence, we propose to generate a compact Abbe's kernel for microlithography aerial image simulation using singular-value decomposition method. The advantages of this approach are as follows: First, since not all the Abbe's kernels have critical effects on aerial image, we can eliminate them to generate a compact one with SVD. Therefore, we can speed up simulation time, and furthermore keep the accuracy user specified. Second, with advanced concentric circles source discretization, equivalent kernels with higher precision is produced. Finally, we can use compact Abbe's kernel to build LUT to speed up simulation time. In this thesis, we introduce some basic knowledge of optical lithography in chapter 1 and some coherent light in optics with analytical solution in chapter 2. Then, partially coherent light concept, advanced illumination aperture and Abbe's method are introduced in chapter 3 and our Abbe-SVD algorithm and advanced source discretization will also be derived. Experimental result and some comparisons will be shown in chapter 4 and finally conclusion will be made in chapter 5.

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