Surface charging effects on etching profiles

Surface charging effects on etching profiles during Si trench etching in a nonuniform plasma were studied using a SEM, a Langmuir probe and an ion lens simulator. A tilt distortion in the etching profile was found near large open etched areas. In addition, bowing was found for small feature patterns. Ion trajectory calculations showed that these profile defects were caused by the local electric field distortion from a potential difference between the charged mask surface and the Si substrate.<
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