Feature profile evolution during shallow trench isolation etching in chlorine-based plasmas. III. The effect of oxygen addition

Abstract

Articles you may be interested inFeature profile evolution during shallow trench isolation etch in chlorine-based plasmas. II. Coupling reactor and feature scale models Feature profile evolution during shallow trench isolation etch in chlorine-based plasmas. I. Feature scale modeling J. Modeling of fluorine-based high-density plasma etching of anisotropic silicon trenches with oxygen sidewall passivation J. Appl. Phys. 94, 6311 (2003); 10.1063/1.1621713Deep-submicron trench profile control using a magnetron enhanced reactive ion etching system for shallow trench isolationThe effect of oxygen addition to chlorine plasma during shallow trench isolation etching is quantified in this work. Specifically, the electron density and the electron temperature in an electron cyclotron resonance reactor were characterized by a Langmuir probe and were found to remain relatively constant upon O 2 addition. The silicon etching rates were found to increase with the square root of the ion energy, suggesting the etching reaction is limited by the momentum transfer from ions to the surface. A relatively small amount of oxygen addition (<10%) to the chlorine plasma simultaneously changes the reactor wall conditions and surface kinetics, since oxygen becomes actively involved in the surface reactions. The change in the chamber wall conditions and surface kinetics leads to the change in both the amount of etch products and the etched feature profile. The incorporation of oxygen on the surface results in a significant change of the etched surface morphology and its composition. This work suggests a small amount of O 2 addition to Cl 2 plasmas in shallow trench isolation etching changes the etching behavior primarily through modifying the kinetics on etched surfaces. A multiscale etch model consisting of translating mixed layer and Monte Carlo modules for bulk and feature scale etching, respectively, was successfully applied to this case, demonstrating good agreement with the experimental results.

Comprehensive Simulations for Ultraviolet Lithography Process of Thick SU-8 Photoresist

“…Etching surface evolvement algorithms are one of the key components for profile simulations, as they must accurately reflect the evolvement without excessive computation. Currently, there are string algorithms [ 89 , 90 , 91 , 92 , 93 , 94 ], ray-tracing algorithms [ 95 , 96 , 97 ], cellular automata algorithms [ 98 , 99 , 100 , 101 , 102 , 103 , 104 , 105 , 106 , 107 , 108 , 109 , 110 ], and fast marching algorithms [ 111 , 112 , 113 , 114 , 115 , 116 , 117 , 118 , 119 , 120 , 121 ] that have been reported for the etching surface evolvement simulation of lithography simulations. Table 1 summarizes brief feature comparisons of these algorithms.…”

“…Surface evolvement is represented by the removal or addition of cells or some parts of cells. For many years, the cellular automata algorithms have been used to simulate the shallow trench isolation etch with chlorine plasma [ 99 , 100 ], plasma etching of SiO 2 [ 101 ], anisotropic etching of silicon [ 101 , 102 , 103 , 104 ], photoresist development [ 105 , 106 , 107 , 108 , 109 ], and so on. A great advantage of the cellular automata algorithms is the ease of handling topological changes for arbitrary geometries and the easy with which they are implemented in 3D.…”