Method and apparatus for optical monitoring in chemical mechanical polishing
AssigneeApplied Materials, Inc.
InventorsAndreas Norbert Wiswesser, Judon Tony Pan, Boguslaw Swedek, Manoocher Birang
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Abstract
An apparatus, as well as a method, brings a surface of a substrate into contact with a polishing pad that has a window, causes relative motion between the substrate and the polishing pad, and directs a light beam through the window so that the motion of the polishing pad relative to the substrate causes the light beam to move in a path across the substrate. Light beam reflections from the substrate are detected, and used to determine polishing parameters, detect process repeatability, and qualify processes.
Claims15
A method of determining polishing parameters, comprising:
- bringing a surface of a substrate into contact with a polishing pad that has a window;
- causing relative motion between the substrate and the polishing pad;
- directing a light beam through the window, the motion of the polishing pad relative to the substrate causing the light beam to move in a path across the substrate;
- detecting light beam reflections from a layer in the substrate;
- generating reflection data associated with the light beam reflections;
- displaying the reflection data from a scan of the light beam across the substrate;
- and
- selecting polishing parameters to provide uniform polishing of the substrate based on the displayed reflection data.
A method of generating endpoint parameters, comprising:
- polishing a first substrate;
- detecting light beam reflections during polishing the first substrate to generate a first plurality of intensity measurements;
- determining a radial range to use for endpoint detection from the first plurality of intensity measurements;
- polishing a second substrate;
- detecting light beam reflections during polishing of a layer in the second substrate to generate a second plurality of intensity measurements;
- calculating a radial position relative to the center of the second substrate for each of the second intensity measurements;
- determining a polishing endpoint from those second intensity measurements which are within the radial range.
A method of determining process uniformity, comprising:
- detecting light beam reflections during polishing of a layer in a first substrate;
- detecting light beam reflections during polishing of a layer in a second substrate;
- generating reflection data associated with the light beam reflections;
- displaying reflection data from a first scan of the light beam across the first substrate;
- displaying reflection data from a second scan of the light beam across the second substrate;
- and
- comparing the reflection data from the first scan to the reflection data from the second scan to determine process uniformity.
Dependencies are inferred from the claim text.