Wafer alignment mark scheme
First Claim
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1. A method comprising:
- directing light in a first direction;
receiving a first reflected light with a first light intensity difference from the light;
receiving a second reflected light with a second light intensity difference from the light, the first light intensity difference being identifiably different from the second light intensity difference, wherein the wafer is rotated during the receiving the first reflected light and the receiving the second reflected light; and
determining a position of the wafer based on the first light intensity difference and the second light intensity difference.
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Abstract
A wafer alignment apparatus includes a light source, a light detection device, and a rotation device configured to rotate a wafer. The light source is configured to provide a light directed to the wafer. The light detection device is configured to detect reflected light intensity from the wafer to locate at least one wafer alignment mark of wafer alignment marks separated by a plurality of angles. At least two of those angles are equal.
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Citations
20 Claims
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1. A method comprising:
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directing light in a first direction; receiving a first reflected light with a first light intensity difference from the light; receiving a second reflected light with a second light intensity difference from the light, the first light intensity difference being identifiably different from the second light intensity difference, wherein the wafer is rotated during the receiving the first reflected light and the receiving the second reflected light; and determining a position of the wafer based on the first light intensity difference and the second light intensity difference. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A method comprising:
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directing light towards a rotating wafer; analyzing a first reflected light from the rotating wafer to determine a first light intensity from a first alignment mark; analyzing a second reflected light from the rotating wafer to determine a second light intensity from a second alignment mark identifiably different from the first light intensity; and determining a position of the rotating wafer based on the first light intensity and the second light intensity. - View Dependent Claims (8, 9, 10, 11, 12, 13)
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14. A method comprising:
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placing a semiconductor wafer onto a rotation device; rotating the semiconductor wafer; while the semiconductor wafer is rotating, reflecting light from a back side of the semiconductor wafer to a light detection device; and determining a position of the semiconductor wafer from two identifiably different light intensities, each light intensity being modified by recesses within the back side of the semiconductor wafer. - View Dependent Claims (15, 16, 17, 18, 19, 20)
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Specification