Geometric advection and its application in the emulation of high aspect ratio structures

Abstract

The ability to simulate the processes required to fabricate advanced microelectronic structures, commonly referred to as process technology computer aided design (TCAD), is essential for the semiconductor industry. It aids in the design and development of modern integrated circuits at low cost. Ongoing demands of high efficiency and simplicity lead to the development of process emulation techniques, which describe the effect of a fabrication step by using only the geometric properties gathered from experimental data or extracted from physical simulations. However, the accuracy of current emulation models is limited by their strong reliance on explicit surface representations, while traditional algorithms employing implicit surfaces, such as the level set, can frequently suffer from numerical limitations. A novel geometric advection algorithm for microelectronic process emulation is presented, which advances a level set surface over large distances in a single simulation step. It combines the advantages of explicit surface representations, such as fast access to surface data and efficient sorting, and the robustness of implicit surface representations. Furthermore, calculations are performed directly in the level set avoiding costly conversions to explicit surfaces. The performance and applicability of the algorithm to modern processes is demonstrated by emulating the fabrication of several high aspect ratio structures. Due to the almost universal applicability and computational efficiency of the presented geometric advection algorithm, it provides an entirely new way of emulating microelectronic fabrication processes and presents a promising alternative to long-standing and commonly used techniques.