Method for automated determination of reticle tilt in a lithographic system

• Main Author: EHRICHS EDWARD E
• Format: Patent
• Language: English
• Published: 18.02.2003
• Edition: 7
• Subjects: APPARATUS SPECIALLY ADAPTED THEREFOR; APPLICATIONS OF SCANNING-PROBE TECHNIQUES, e.g. SCANNING PROBEMICROSCOPY [SPM]; CALCULATING; CINEMATOGRAPHY; COMPUTING; COUNTING; ELECTROGRAPHY; HOLOGRAPHY; IMAGE DATA PROCESSING OR GENERATION, IN GENERAL; MATERIALS THEREFOR; MEASURING; ORIGINALS THEREFOR; PHOTOGRAPHY; PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES,e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTORDEVICES; PHYSICS; SCANNING-PROBE TECHNIQUES OR APPARATUS; TESTING

A method, system, and storage medium for determining retide tilt in a lithographic system is provided. Test patterns contained on a reticle are printed in a photoresist located on an upper surface of a semiconductor substrate by a lithographic system. The test patterns may include three posts of different diameters wherein one of the diameters is approximately equal to the minimum allowable feature size printable by the lithographic system. Images of the test patterns are measured by a scanning electron microscope under the control of a computer system. The computer system then assesses the measured images of the test patterns to determine if the reticle tilt is acceptable or unacceptable. In one embodiment, the computer system may assess the measured images by comparing the measured images to predetermined images of the test patterns for different focus conditions. The computer system may also calculate the amount of reticle tilt. In an alternative embodiment, the computer system may assess the measured images by comparing the measured images to each other.