Method for performing an alignment measurement of two patterns in different layers on a semiconductor wafer

• Main Authors: HEINE ROLF, SCHEDEL THORSTEN, SCHMIDT SEBASTIAN
• Format: Patent
• Language: English
• Published: 21.06.2005
• Edition: 7
• Subjects: APPARATUS SPECIALLY ADAPTED THEREFOR; BASIC ELECTRIC ELEMENTS; CALCULATING; CINEMATOGRAPHY; COMPUTING; COUNTING; ELECTRIC SOLID STATE DEVICES NOT OTHERWISE PROVIDED FOR; ELECTRICITY; ELECTROGRAPHY; HOLOGRAPHY; IMAGE DATA PROCESSING OR GENERATION, IN GENERAL; MATERIALS THEREFOR; ORIGINALS THEREFOR; PHOTOGRAPHY; PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES,e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTORDEVICES; PHYSICS; SEMICONDUCTOR DEVICES

In an alignment or overlay measurement of patterns on a semiconductor wafer an error that occurs during the measurement in one of a predefined number of alignment structures in an exposure field of a corresponding predefined set of exposure fields can be handled by selecting an alignment structure in a substitute exposure field. The latter exposure field need not be part of the predefined set of exposure fields, that is, an inter-field change may be effected. The number of alignment measurements on a wafer remains constant and the quality is increased. Alternatively, when using another alignment structure in the same exposure field-by effecting an intra-field change-the method becomes particularly advantageous when different minimum structure sizes are considered for the substitute targets. Due to the different selectivity in, say, a previous CMP process, such targets might not erode and do not cause an error in a measurement, thus providing an increased alignment or overlay quality.