Methods and systems for detecting a presence of blobs on a specimen during a polishing process

摘要

Systems and methods for detecting a presence of blobs on a specimen are provided. One method may include scanning measurement spots across a specimen during polishing of the specimen. The method may also include determining if the blobs are present on the specimen at the measurement spots. Each of the blobs may include unwanted material disposed upon a contiguous portion of the measurement spots. In some instances, the blobs may include copper. In some embodiments, scanning the measurement spots may include measuring an optical property and/or an electrical property of the specimen at the measurement spots. Another embodiment includes dynamically determining a signal threshold distinguishing a presence of the blobs from an absence of the blobs. An additional embodiment includes determining an endpoint of polishing if, for example, blobs are not determined to be present on the specimen.