MONITORING CHANGES IN PHOTOMASK DEFECTIVITY

摘要

A reticle that is within specifications is inspected so as to generate a baseline event indicating a location and a size value for each unusual reticle feature. After using the reticle in photolithography, the reticle is inspected so as to generate a current event indicating a location and a size value for each unusual reticle feature. An inspection report of candidate defects and their images is generated so that these candidate defects include a first subset of the current events and their corresponding candidate defect images and exclude a second subset of the current events and their corresponding excluded images. Each of the first included events has a location and size value that fails to match any baseline event's location and size value, and each of the excluded second events has a location and size value that matches a baseline event's location and size value.

主权项

1. A method of inspecting a photolithographic reticle, the method comprising:
performing a first single-die inspection of a reticle that is has been identified as being within specifications so as to generate a plurality of baseline events corresponding to a plurality of unusual baseline features of the reticle, wherein each baseline event indicates a location and a size value for a corresponding unusual baseline feature; after using the reticle in one or more photolithography processes, performing via a reticle inspection tool a second single-die inspection of the reticle so as to generate a plurality of current events corresponding to a plurality of current unusual features of the reticle, wherein each current event indicates a location and a size value for a corresponding current unusual feature; and generating an inspection report of a plurality of candidate reticle defects and their images, wherein the candidate defects include a first subset of the current events and their corresponding plurality of candidate defect images and exclude a second subset of the current events and their corresponding plurality of excluded images, wherein each of the first subset of events included in the inspection report has a location and size value that fails to match any baseline event's location and size value by a predefined amount, and each of the second subset of events excluded from the inspection report has a location and size value that matches any baseline event's location and size value by the predefined amount.