In situ conductivity monitoring technique for chemical/mechanical planarization endpoint detection
First Claim
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1. An apparatus for monitoring the conductivity of an exposed surface of a workpiece during polishing in a lapping machine, comprising:
- a plurality of isolated electrode means coupled to the lapping machine, at least one of said plurality of isolated electrode means contacting a surface of the workpiece; and
means for monitoring current flow between said plurality of isolated electrode means, said current indicating the amount of conductive material at the exposed surface of the substrate.
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Abstract
An apparatus and method for monitoring the conductivity of a semiconductor wafer during the course of a polishing process. A polishing pad that contacts the wafer has an active electrode and at least one passive electrode, both of which are embedded in the polishing pad. A detecting device is connected to the active and passive electrodes for monitoring the current between the electrodes as the wafer is lapped by the polishing pad. The etch endpoint of the wafer is determined as a function of the magnitude of the current flow.
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Citations
18 Claims
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1. An apparatus for monitoring the conductivity of an exposed surface of a workpiece during polishing in a lapping machine, comprising:
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a plurality of isolated electrode means coupled to the lapping machine, at least one of said plurality of isolated electrode means contacting a surface of the workpiece; and means for monitoring current flow between said plurality of isolated electrode means, said current indicating the amount of conductive material at the exposed surface of the substrate. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. An apparatus for determining an etch endpoint, during a lapping process, of a work piece having at least one conductive portion and at least one insulative portion, comprising:
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means for planarizing the work piece; an active electrode and at least one passive elecrode, both of which are coupled to said planarizing means; and means, coupled to said active and said at least one passive electrode, for electrically detecting when said active and passive electrodes contact the conductive portion of the work piece, whereby the etch endpoint of the work piece is determined by monitoring an output of said detecting means. - View Dependent Claims (10, 11, 12, 13, 14)
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- 15. A polishing pad for controllably lapping a work piece having at least one insulative portion and at least one non-insulative portion, said pad comprising an insulative support structure having an active electrode and at least one passive electrode embedded therein, said active and passive electrodes contacting respective portions of the work piece, so that during the lapping process the existence of current flow through said passive electrode indicates that portions of the non-insulative portion of the work piece are in contact with both the active and passive electrodes of the polishing pad.
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18. A method for monitoring the conductivity of a work piece during the course of a lapping process carried out in a lapping machine having a polishing pad that contacts the work piece, the polishing pad having an active electrode and at least one passive electrode contacting the work piece, comprising the step of:
monitoring the current flow between said active and at least one passive electrode of the polishing pad during the polishing process.
Specification