Laser alignment target for semiconductor integrated circuits
AssigneeAltera Corporation
InventorsKevin A. Norman, Kamlapati Khalsa
Life of this patent
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Abstract
An alignment target for use in aligning a semiconductor wafer using a scanning light beam includes a light reflective surface of a first material such as aluminum which defines an alignment pattern and a light scattering surface of a second material abutting the light reflective surface, the light scattering surface including a raised pattern of generally orthogonal lines with the lines having inclined sidewalls which scatter impinging light. In a preferred embodiment the second material is polycrystalline silicon which has been etched to form the pattern with inclined sidewalls.
Claims16
An alignment target for use in aligning a semiconductor wafer using a scanning light beam comprising a light reflective surface of a first material defining an alignment pattern, and a light scattering surface of a second material abutting said light reflecting surface, said light scattering surface including a raised pattern of generally orthogonal lines formed in said second material, each line having inclined sidewalls which scatter impinging light.
A work piece comprising a semiconductor wafer having a major surface, a plurality of integrated circuits formed in said major surface, and a plurality of alignment targets for determining position and rotation of said semiconductor wafer relative to a scanning light beam, each alignment target including a light reflective surface of a first material defining an alignment target, and a light scattering surface of a second material abutting said light reflecting surface, said light scattering surface including a raised pattern of generally orthogonal lines formed in said second material, each line having inclined sidewalls which scatter impinging light.
Dependencies are inferred from the claim text.