Simplified wafer alignment
AssigneeAxcelis Technologies, Inc.
InventorAndrew M. Ray
Life of this patent
Estimating the term…
Abstract
The present invention is directed to aligning wafers within semiconductor fabrication tools. More particularly, one or more aspects of the present invention pertain to quickly and efficiently finding an alignment marking, such as an alignment notch, on a wafer to allow the wafer to be appropriately oriented within an alignment tool. Unlike conventional systems, the notch is located without firmly holding and spinning or rotating the wafer. Exposure to considerable backside contaminants is thereby mitigated and the complexity and/or cost associated with aligning the wafer is thereby reduced.
Claims15
A system adapted to locate an alignment marking on a semiconductor wafer comprising:
- a shaft;
- a sleeve moveably mounted upon the shaft;
- one or more support pins mounted to one end of the shaft and adapted to support a wafer situated thereon;
- and
- an arm member operatively coupled to the sleeve, an end of the arm member extending up toward the wafer when the wafer resides on the one or more support pins, the end of the arm member operative to establish a beam of radiation that may be intersected by the perimeter of the wafer, wherein the wafer can be scanned when on the support pins by rotating the arm member around the perimeter of the wafer and the marking can be identified by a change in the amount of radiation transmitted past the wafer.
A mechanism adapted to locate an alignment marking on a semiconductor wafer comprising:
- a support structure for supporting the wafer, the support structure contacting a small amount of surface area of a backside of the wafer to mitigate particle contamination;
- a member that moves relative to the wafer when the wafer is supported on the support structure and that directs a beam of radiation having a substantially elliptical cross section at the perimeter of the wafer;
- and
- a controller operatively coupled to the member to regulate the movement of the member and to obtain scan data from one or more sensors relating to the amount of radiation transmitted past the wafer at various locations around the wafer, and to identify the marking when there is a change in the amount of radiation transmitted past the wafer and to identify a center of the wafer by observing gradual changes in the amount of radiation transmitted past the wafer at various locations around the wafer.
Dependencies are inferred from the claim text.