In-situ substrate imaging

Abstract

Methods and products, including computer program products, for endpoint determination. An image of a portion of a substrate is captured in-situ, where the image includes optical information that depends on a thickness of a substrate layer. The image is examined to find a location on the substrate, and a process endpoint is determined using a portion of the optical information that corresponds to the location.

Description

technical field [0001] The present invention relates to chemical mechanical polishing of substrates. Background technique [0002] Integrated circuits are typically formed on a silicon substrate by sequentially depositing conductive, semiconductive, or insulating layers on a silicon substrate. One fabrication step involves depositing a filler layer on a non-planar surface and planarizing the filler layer until the non-planar surface is exposed. For example, a metal filler layer can be deposited on the patterned oxide layer to fill trenches or holes in the oxide layer. The filler layer is then polished until the raised pattern of the oxide layer is exposed. After planarization, the portion of the metal layer remaining in the trench provides circuitry on the substrate. In addition, the substrate surface to be subjected to photolithography also needs to be planarized. [0003] Chemical mechanical polishing (CMP) is a well-established planarization method. This planarizatio...

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Problems solved by technology

Alternatively, inspection may reveal that excess material has been removed, thereby rendering the substrate unusable

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