Abstract: A measurement device and method for focusing and leveling are disclosed. The device includes a measuring optical path and a first monitoring optical path. Measuring light in the measuring optical path interacts with a wafer and is then incident on a measuring detector to form thereon a measuring mark. First monitoring light in the first monitoring optical path is incident on a measuring detector to form thereon a first monitoring mark. An error in a measurement result of the wafer that arises from a drift of the measuring detector can be eliminated by compensating for a vertical deviation of the wafer obtained by subtracting a drift of the first monitoring mark from a displacement of the measuring mark. In this way, measurement accuracy and stability can be improved by monitoring and correcting the drift of the measuring detector.

Abstract: A measurement device and method for focusing and leveling are disclosed. The device includes a measuring optical path and a first monitoring optical path. Measuring light in the measuring optical path interacts with a wafer and is then incident on a measuring detector to form thereon a measuring mark. First monitoring light in the first monitoring optical path is incident on a measuring detector to form thereon a first monitoring mark. An error in a measurement result of the wafer that arises from a drift of the measuring detector can be eliminated by compensating for a vertical deviation of the wafer obtained by subtracting a drift of the first monitoring mark from a displacement of the measuring mark. In this way, measurement accuracy and stability can be improved by monitoring and correcting the drift of the measuring detector.