METHODS OF CONTROLLING EUV EXPOSURE DOSE, EUV LITHOGRAPHIC METHODS AND APPARATUS USING SUCH METHODS
PROBLEM TO BE SOLVED: To provide new dose control methods in order to optimize the number of dies that can be exposed per unit of time.SOLUTION: The EUV exposure dose in a lithographic apparatus is controlled pulse by pulse by varying the conversion efficiency with which a pulse of EUV radiation is...
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Main Authors | , , , , |
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Format | Patent |
Language | English |
Published |
22.04.2013
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Subjects | |
Online Access | Get full text |
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Summary: | PROBLEM TO BE SOLVED: To provide new dose control methods in order to optimize the number of dies that can be exposed per unit of time.SOLUTION: The EUV exposure dose in a lithographic apparatus is controlled pulse by pulse by varying the conversion efficiency with which a pulse of EUV radiation is generated from excitation of a fuel material by a corresponding pulse of excitation laser radiation. The conversion efficiency can be varied in several different ways, by varying the proportion of a fuel material that interacts with a laser beam, and/or by varying quality of the interaction. Mechanisms of varying the conversion efficiency can be based on variation of laser pulse timing, variation of pre-pulse energy, and/or variable displacement of a main laser beam in one or more directions. Steps of maintaining symmetry of the generated EUV radiation can be included. |
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Bibliography: | Application Number: JP20120206219 |