Scan Direction and Scan Step Matching Tooling

摘要

Various types of scanners (DUV, EUV.I- Mine) are used to expose layers depending on their availability, and different types of scanners have different expose start points. Hence, although for the same layer and the same field, scan direction across the field and step direction from field to field can be different depending on the scanner type which is used for exposing the wafer. A mismatch between layers of scan direction / step direction may increase the chance of inducing larger than desired overlay error (OV). The scan direction can be either upwards (SU) or downwards (SD). The step direction can be from left to right (SL) or from right to left (SR). In the figure below a first configuration (bottom figures) of matched step&scan conditions and unmatched stap&scan conditions (top figures) is depicted.