Compensation for substrate doping for in-situ electromagnetic inductive monitoring

Abstract

A method of chemical mechanical polishing includes bringing a substrate having a conductive layer disposed over a semiconductor wafer into contact with a polishing pad, generating relative motion between the substrate and the polishing pad, monitoring the substrate with an in-situ electromagnetic induction monitoring system as the conductive layer is polished to generate a sequence of signal values that depend on a thickness of the conductive layer, determining a sequence of thickness values for the conductive layer based on the sequence of signal values, and at least partially compensating for a contribution of conductivity of the semiconductor wafer to the signal values.

Description

technical field [0001] The present disclosure relates to chemical mechanical polishing, and more particularly to monitoring conductive layers during chemical mechanical polishing. Background technique [0002] Integrated circuits are typically formed on a substrate by sequentially depositing conductive, semiconductive, or insulating layers on a silicon wafer. Various fabrication processes require planarization of layers on a substrate. For example, one fabrication step involves depositing a fill layer on a non-planar surface and planarizing the fill layer. For some applications, the fill layer is planarized until the upper surface of the patterned layer is revealed. For example, a metal layer may be deposited on a patterned insulating layer to fill trenches and holes in the insulating layer. After planarization, the remainder of the metal in the trenches and holes of the patterned layer forms vias, plugs, and lines to provide conductive paths between thin film circuits on...

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Problems solved by technology

Thus, determining the grinding endpoint with respect to grinding time alone may result in non-uniformity within the wafer or from wafer to wafer

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