REDUCING SPECKLE IN AN EXCIMER LIGHT SOURCE

• Main Authors: op 't Root, Wilhelmus Patrick Elisabeth Maria, Thornes, Joshua Jon, Godfried, Herman Philip, King, Brian Edward, Everts, Frank, Duffey, Thomas Patrick
• Format: Patent
• Language: English
• Published: 24.10.2019
• Subjects: APPARATUS SPECIALLY ADAPTED THEREFOR; BASIC ELECTRIC ELEMENTS; CINEMATOGRAPHY; COLORIMETRY; DEVICES OR ARRANGEMENTS, THE OPTICAL OPERATION OF WHICH ISMODIFIED BY CHANGING THE OPTICAL PROPERTIES OF THE MEDIUM OF THEDEVICES OR ARRANGEMENTS FOR THE CONTROL OF THE INTENSITY,COLOUR, PHASE, POLARISATION OR DIRECTION OF LIGHT, e.g.SWITCHING, GATING, MODULATING OR DEMODULATING; DEVICES USING STIMULATED EMISSION; ELECTRICITY; ELECTROGRAPHY; FREQUENCY-CHANGING; HOLOGRAPHY; MATERIALS THEREFOR; MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT,POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRA-RED,VISIBLE OR ULTRA-VIOLET LIGHT; MEASURING; NON-LINEAR OPTICS; OPTICAL ANALOGUE/DIGITAL CONVERTERS; OPTICAL ELEMENTS, SYSTEMS, OR APPARATUS; OPTICAL LOGIC ELEMENTS; OPTICS; ORIGINALS THEREFOR; PHOTOGRAPHY; PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES,e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTORDEVICES; PHYSICS; RADIATION PYROMETRY; TECHNIQUES OR PROCEDURES FOR THE OPERATION THEREOF; TESTING

A method includes: producing a light beam made up of pulses having a wavelength in the deep ultraviolet range, each pulse having a first temporal coherence defined by a first temporal coherence length and each pulse being defined by a pulse duration; for one or more pulses, modulating the optical phase over the pulse duration of the pulse to produce a modified pulse having a second temporal coherence defined by a second temporal coherence length that is less than the first temporal coherence length of the pulse; forming a light beam of pulses at least from the modified pulses; and directing the formed light beam of pulses toward a substrate within a lithography exposure apparatus.