Methods and apparatus for detecting multiple objects
AssigneeLam Research Corporation
InventorsRobert Bond, Fareed Nabkel, Richard Adachi
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Abstract
A method for determining physical placement data for a plurality of wafers is disclosed. The method includes obtaining raw CCD array data from a linear CCD array by clocking data from pixels of the linear CCD array into memory cells of the memory device and ascertaining pixel transition data to determine whether at least one of an upper edge error, a lower edge error, a wafer thickness error, and transition-per-slot error exists. If an error is found, the method includes generating an error signal.
Claims20
A method for determining physical placement data for a plurality of wafers, said plurality of wafers being disposed on a plurality of parallel sets of fingers using a linear CCD array and a memory device and a logic module, comprising:
- obtaining raw CCD array data, said obtaining including serially clocking data from pixels of said linear CCD array into memory cells of said memory device;
- ascertaining, using said logic module and said memory device, pixel transition data from at least one of said raw CCD array data and filtered CCD array data, said pixel transition data including a number of transitions between adjacent pixel pairs and locations of said transitions;
- ascertaining, using said logic module and said pixel transition data, whether at least one of an upper edge error, a lower edge error, a wafer thickness error, and transition-per-slot error exists;
- and
- if said at least one of said upper edge error, said lower edge error, said wafer thickness error, and said transition-per-slot error exists, generating an error signal.
In a plasma processing system, a method for determining physical placement data for a plurality of wafers, comprising:
- placing a plurality of wafers on a plurality of parallel sets of fingers;
- illuminating a linear CCD array using a light source, the plurality of wafers being disposed between the linear CCD array and the light source;
- obtaining raw CCD array data, said obtaining including serially clocking data from pixels of said linear CCD array into memory cells of a memory device;
- ascertaining, using a logic module and said memory device, pixel transition data from at least one of said raw CCD array data and filtered CCD array data, said pixel transition data including at least a number of transitions between adjacent pixel pairs and locations of said transitions;
- and
- ascertaining, using said logic module and said pixel transition data, whether at least one of an upper edge error, a lower edge error, a wafer thickness error, and transition-per-slot error exists;
- if said at least one of said upper edge error, said lower edge error, said wafer thickness error, and said transition-per-slot error exists, generating an error signal.
Dependencies are inferred from the claim text.