Chemical mechanical polishing endpoint detection
AssigneeNutool, Inc.
InventorsYuchun Wang, Bernard M. Frey, Bulent M. Basol, Douglas W. Young, Homayoun Talieh, Efrain Velazquez
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Abstract
The methods and systems described provide for an in-situ endpoint detection for material removal processes such as chemical mechanical processing (CMP) performed on a workpiece. In a preferred embodiment, an optical detection system is used to detect endpoint during the removal of planar conductive layers using CMP. An optically transparent polishing belt provides endpoint detection through any spot on the polishing belt. Once endpoint is detected, a signal can be used to terminate or alter a CMP process that has been previously initiated.
Claims29
A chemical mechanical polishing (CMP) apparatus for polishing a surface of a workpiece and for detecting a CMP endpoint, comprising:
- an optically transparent polishing belt to polish the surface of the workpiece, the polishing belt being movable in one or more linear directions;
- a workpiece holder to support the workpiece, the workpiece holder configured to press the workpiece against the polishing belt;
- a support plate adapted to support the polishing belt as the workpiece is pressed against the polishing belt;
- and
- an optical detection system to detect the CMP endpoint, the optical detection system disposed below the polishing belt and comprising a light source and a detector, the light source sending outgoing signals through the polishing belt to the surface of the workpiece and the detector receiving incoming reflected signals from the surface of the workpiece through the polishing belt wherein the polishing belt is moved bi-directionally.
A method of polishing a surface of a workpiece and of detecting a chemical mechanical polishing (CMP) endpoint, comprising:
- pressing the workpiece against an optically transparent polishing belt, the polishing belt being supported by a support plate;
- polishing the surface of the workpiece with the polishing belt, wherein the polishing belt is movable in one or more linear directions;
- sending outgoing optical signals from a light source through the polishing belt to the surface of the workpiece, the light source disposed below the polishing belt so that the polishing belt is between the light source and the surface of the workpiece;
- receiving, at a detector, incoming reflected optical signals from the surface of the workpiece through the polishing belt and the support plate, the detector disposed below the polishing belt;
- and
- moving the light source and the detector to permit detection of the CMP endpoint over the surface of the workpiece.
A method of polishing one or more workpieces and of providing chemical mechanical polishing (CMP) endpoint detection, comprising:
- providing an optically transparent polishing belt between a supply area and a receive area, the polishing belt having a first end and a second end and a polishing side and a backside, such that the first end initially comes off the supply area and is connected to the receive area and the second end remains connected to the supply area;
- polishing a first workpiece by moving a portion of the polishing belt in one or more linear directions within a polishing area;
- and
- detecting a first CMP endpoint of the first workpiece using an optical detection system, the optical detection system sending outgoing signals to and receiving incoming reflected signals from the first workpiece through the polishing belt, the polishing belt being located between the optical detection system and the first workpiece.
A method of polishing a surface of a workpiece and of detecting a chemical mechanical polishing (CMP) endpoint, comprising:
- supporting the workpiece such that the surface of the workpiece is exposed to a section of an optically transparent polishing belt in a processing area;
- and
- polishing the surface of the wafer by moving the section of the polishing belt bi-directional linearly;
- and
- determining a CMP endpoint for the workpiece by sending outgoing optical signals through the polishing belt to the workpiece and continuously examining the relative intensity of incoming optical signals reflected from the workpiece and received through the polishing belt.
Dependencies are inferred from the claim text.