ASML Holding N.V.
Athermalization of an alignment system

Abstract:

An alignment system configured to be substantially insensitive to thermal variations in its system during alignment measurements. The alignment system includes a sensor system, a support structure, a sensing element, a position measurement system, and an athermal interface between the sensing element and the support structure. The sensor system is configured to determine a position of an alignment mark on a substrate and the support structure is configured to support the sensor system. The sensing element is configured to detect an unintentional displacement of the support structure and the position measurement system is configured to measure the unintentional displacement relative to a reference element based on the detected unintentional displacement. The athermal interface is configured to prevent detection of temperature induced displacement of the support structure by the sensing element.