摘要 |
A pattern generator includes: a writing tool and a calibration system. The writing tool is configured to generate a pattern on a workpiece arranged on a stage. The calibration system is configured to determine a correlation between a coordinate system of the writing tool and a coordinate system of a calibration plate on one of the stage and the workpiece. The calibration system is also configured to determine the correlation at least partly based on an optical correlation signal, or pattern, in a form of at least one optical beam being reflected from at least one reflective pattern on the surface of the calibration plate. |