Target locking system for electron beam lithography

• Main Authors: KENDALL, RODNEY A, HARTLEY, JOHN G
• Format: Patent
• Language: English; French; German
• Published: 02.05.2007
• Subjects: APPARATUS SPECIALLY ADAPTED THEREFOR; BASIC ELECTRIC ELEMENTS; CINEMATOGRAPHY; COLORIMETRY; ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS; ELECTRIC SOLID STATE DEVICES NOT OTHERWISE PROVIDED FOR; ELECTRICITY; ELECTROGRAPHY; HOLOGRAPHY; MATERIALS THEREFOR; MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT,POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRA-RED,VISIBLE OR ULTRA-VIOLET LIGHT; MEASURING; ORIGINALS THEREFOR; PHOTOGRAPHY; PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES,e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTORDEVICES; PHYSICS; RADIATION PYROMETRY; SEMICONDUCTOR DEVICES; TESTING

An e-beam lithographic system capable of in situ registration. The system has an optics section such as a VAIL lens. A controllable stage moves a substrate with respect to the beam axis to place substrate writing fields beneath the beam. A field locking target between the optics section and the stage has an aperture sized to permit the beam to write a target field on the substrate. The field locking target includes alignment or registration marks around the aperture. A differential interferometric system measures the relative positions of the field locking target and the stage and controls stage position. The beam patterns the substrate on a field by field basis. As the stage is moving into position for each field, the beam is swept until it hits the alignment marks, thereby checking system alignment. The beam control data, i.e., coil currents necessary to hit the marks are stored, and drift correction values calculated from the beam control data. Meanwhile, pattern beam control is compensated by the drift correction values.