Out of contact optical alignment and exposure apparatus

Abstract

Abstract A CALIBRATOR IS RETRACTABLY POSITIONED BETWEEN A MASKBEARING HOLDER AND A WATER-BEARING CHUCK POSITIONED BENEATH THE HOLDER AND PROVIDED WITH A PERIPHERAL LOCKING RING STRUCTURE THAT MAY BE RETRACTABLY DRIVEN UPWARD ABOVE THE UPPER SURFACE OF THE WATER AND LOCKED IN PLACE. THE LOCKING RING STRUCTURE INCLUDES AN EXPANDABLE GENERALLY U-SHAPED LOCKING RING WITH AN INWARDLY CURVED BOTTOM WALL THAT IS FORCED OUTWARD BY AN INFLATABLE TUBE TO EXPAND THE SIDE WALLS OF THE LOCKING RING INTO LOCKING ENGAGEMENT WITH A PERIPHERAL PORTION OF THE CHUCK. A FIRST PISTION DRIVES THE CHUCK UPWARD TO POSITION A PERIPHERAL PORTION OF THE UPPER SURFACES OF THE WATER IN ABUTMENT UPON A FIRST PORTION OF THE CALIBRATOR. THE LOCKING RING STRUCTURE OF THE CHUCK IS DRIVEN FURTHER UPWARD INTO ABUTMENT UPON A SECOND PORTION OF THE CALIBRATOR, WHICH IS INWARDLY OFFSET FROM THE FIRST PORTION BY A SELECTED DISTANCE, AND LOCKED IN PLACE. NEXT, THE CHUCK IS LOWERED AND THE CALIBRATOR RETRACTED FROM BETWEEN THE CHUCK AND THE HOLDER. THE CHUCK IS THEN DRIVEN UPWARD AGAIN BY THE FIRST PISTON TO POSITION THE LOCKING RING STRUCTURE OF THE CHUCK IN ABUTMENT UPON A MARGINAL PORTION OF THE LOWER SURFACE OF THE MASK AND THEREBY ESTABLISH PARALLEL PLANE ALIGNMENT BETWEEN THE UPPER SURFACE OF THE WATER AND THE LOWER SURFACE OF THE MASK WITHOUT BRINGING THE WAFER INTO CONTACT WITH THE MASK. AT THIS POINT, THE FIRST PISTON IS LOCKED IN PLACE AND THE LOCKING RING STRUCTURE OF THE CHUCK RELEASED AND RETURNED TO ITS INITIAL POSITION TO PERMIT OUT OF CONTACT ALIGNMENT OF A PATTERN ON THE WAFER WITH A PATTERN ON THE MASK. AFTER THIS ALIGNMENT OPERATION, THE CHUCK IS EITHER RETAINED IN THE ALIGNMENT POSITION OR DRIVEN UPWARD BY A SECOND PISTION TO A POSITION CLOSER TO THE MASK. A PHOTOSENSITIVE FILM ON THE UPPER SURFACE OF THE WAFER MAY THEREFORE TO EXPOSED THROUGH THE MASK WHILE THE WAFER IS IN THE ALIGNMENT POSITION OR AN ELEVATED POSITION CLOSER TO THE MASK. FOLLOWING THIS EXPOSURE OPERATION, THE FIRST PISTON IS RELEASED AND THE CHUCK RETURNED TO ITS INITIAL POSITION. THESE OUT OF CONTACT ALIGNMENT AND EXPOSURE OPERATIONS MAY ALSO BE ACCOMPLISHED WITHOUT A CALIBRATOR OR A CHUCK HAVING A PERIPHERAL LOCKING RING STRUCTURE BY EMPLOYING A CHUCK HAVING A PERIPHERAL SPACING RING THAT MAY BE DRIVEN UPWARD A SELECTED DISTANCE ABOVE THE UPPER SURFACE OF A WAFER POSITIONED ON THE CHUCK.

Inventors

• 👤 Karl-Heinz Johannsmeier

Bibliographic Details