In-situ monitoring of conductive films on semiconductor wafers
AssigneeInternational Business Machines Corporation
InventorsLeping Li, Steven George Barbee, Arnold Halperin, Tony Frederick Heinz
Life of this patent
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Abstract
The change in thickness of a film on an underlying body such as a semiconductor substrate is monitored in situ by inducing a current in the film, and as the thickness of the film changes (either increase or decrease), the changes in the current are detected. With a conductive film, eddy currents are induced in the film by a generating an alternating electromagnetic field with a sensor which includes a capacitor and an inductor.
Claims64
An apparatus for in-situ monitoring of chemical-mechanical polishing a conductive film on a front side of a semiconductor wafer using a tool including a metal wafer carrier which holds the wafer by a back side opposite the front side, comprising:
- a sensor positioned in the carrier proximate the back side of the wafer, the sensor including
- (a) an inductor for inducing a current in the film by producing an alternating electromagnetic field proximate the film, and
- (b) means for shaping the alternating electromagnetic field so that the field is unaffected by the carrier;
- a capacitor electrically coupled to the inductor;
- and detecting means for detecting a change in the current due to a change in the thickness of the film, the detecting means electrically coupled to the sensor and the capacitor.
An apparatus for in-situ monitoring of a process for changing the thickness of a conductive film from a front side of a semiconductor wafer using a tool including a metal wafer support means which supports the wafer by a back side opposite the front side, comprising:
- a sensor positioned in the support means proximate the back side of the wafer, the sensor including
- (a) an inductor for inducing a current in the film by producing an alternating electromagnetic field proximate the film, and
- (b) means for shaping the alternating electromagnetic field so that the field is unaffected by the support means;
- a capacitor electrically coupled to the inductor;
- and detecting means for detecting a change in the current due to a change in the thickness of the film, the detecting means electrically coupled to the sensor and the capacitor.
Dependencies are inferred from the claim text.