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US 5,957,749 AGranted
Apparatus for optical inspection of wafers during polishing
AssigneeNova Measuring Instruments Ltd.
InventorMoshe Finarov
Life of this patent
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Abstract
An optical system is disclosed for the inspection of wafers during polishing which also includes a measurement system for measuring the thickness of the wafer's top layer. The optical system views the wafer through a window and includes a gripping system, which places the wafer in a predetermined viewing location while maintaining the patterned surface completely under water. The optical system also includes a pull-down unit for pulling the measurement system slightly below the horizontal prior to the measurement and returns the measuring system to the horizontal afterwards.
Claims3
A wafer polishing apparatus comprising:
- a polishing unit for polishing a top layer of a wafer in the presence of a liquid;
- an optical measurement station in communication with said polishing unit;
- and
- means for moving said wafer from said polishing unit to said optical measurement station, while said wafer is still wet;
- said optical measurement station comprising;
- a liquid holding unit for receiving said wafer, said liquid holding unit having a bottom surface, and at least a portion of said bottom surface formed by a window, through which at least a portion of said top layer of said wafer is viewable;
- and
- an optical thickness measuring unit in operative communication with said liquid holding unit, said optical thickness measuring unit for measuring the thickness of said top layer of said wafer through said window while said wafer is in said liquid holding unit.
5 more elements
Dependencies are inferred from the claim text.