Endpoint monitoring with polishing rate change
AssigneeApplied Materials, Inc.
InventorsStan Tsai, Fred C. Redeker, Kapila Wijekoon
Life of this patent
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Abstract
A substrate with a first layer disposed on a second layer is chemically mechanically polished. A polishing endpoint detection system generates a signal that is monitored for an endpoint criterion. The polishing rate of the substrate is reduced when the bulk of the first layer has been removed but before the second layer is exposed. For example, the polishing rate is reduced when the polishing time approaches an expected polishing end time but before the endpoint criterion is detected. Polishing stops once the endpoint criterion is detected after the underlying layer has been exposed.
Claims19
A computer-implemented endpoint detection method for a chemical mechanical polishing operation, comprising:
- measuring a polishing time of a substrate being polished by a chemical mechanical polishing system at a first polishing rate;
- receiving a signal from a polishing endpoint detection system;
- monitoring the signal for an endpoint criterion;
- modifying a polishing parameter of the chemical mechanical polishing operation so as to reduce a polishing rate of the substrate being polished to a second polishing rate which is less than the first polishing rate when the polishing time approaches an expected polishing end time but before the endpoint criterion is detected;
- and
- stopping polishing once the endpoint criterion is detected.
A method of chemical mechanical polishing, comprising:
- bringing a substrate into contact with a polishing surface;
- creating relative motion between the substrate and the polishing surface to polish the substrate at a first polishing rate;
- measuring a polishing time of the substrate;
- generating a signal with a polishing endpoint detection system;
- monitoring the signal for an endpoint criterion;
- reducing a polishing rate of the substrate being polished to a second polishing rate which is less than the first polishing rate when the polishing time approaches an expected polishing end time but before the endpoint criterion is detected;
- and
- stopping polishing once the endpoint criterion is detected.
A method of chemical mechanical polishing a substrate having a first layer disposed on a second layer, comprising:
- bringing the first layer of the substrate into contact with a polishing surface;
- creating relative motion between the substrate and the polishing surface to polish the first layer of the substrate at a first polishing rate;
- reducing a polishing rate of the substrate to a second polishing rate which is less than the first polishing rate before the second layer is exposed;
- and
- stopping polishing after the second layer has been exposed.
A chemical mechanical polishing apparatus, comprising:
- a polishing surface;
- a carrier head to hold a substrate into contact with the polishing surface;
- a motor coupled to at least one of the polishing surface and the carrier head to create relative motion therebetween;
- a polishing endpoint detection system;
- a controller to receive a signal from the endpoint system, the controller configured to measure a polishing time of a substrate during a polishing operation, polish the substrate at a first polishing rate, monitor the signal for an endpoint criterion, modify a polishing parameter so as to reduce a polishing rate of the substrate to a second polishing rate which is less than the first polishing rate when the polishing time approaches an expected polishing end time but before the endpoint criterion is detected, and stop polishing of the substrate once the endpoint criterion is detected.
A computer-implemented endpoint detection method for a chemical mechanical polishing operation, comprising:
- measuring a total polishing time of a substrate being polished by a chemical mechanical polishing system;
- receiving a signal from a polishing endpoint detection system;
- monitoring the signal for an endpoint criterion;
- comparing the total polishing time to a default time which is less than an expected polishing end time;
- modifying a polishing parameter of the chemical mechanical polishing operation so as to reduce a polishing rate of the substrate being polished when the default time has elapsed;
- and
- stopping polishing once the endpoint criterion is detected.
Dependencies are inferred from the claim text.