Optical system, in particular for microlithography, and method for operating an optical system
AssigneeCarl Zeiss SMT GmbH
InventorsConrad Wolke, Barbara Moser
Life of this patent
Estimating the term…
Abstract
An optical system, in particular for microlithography, comprises a laser light source for generating a multiplicity of light pulses, and a control unit configured to control the laser light source in such a way that, for a light pulse sequence generated by the laser light source, the time period between respectively successive light pulses varies across the light pulse sequence. A method comprises operating the optical system.
Claims19
An optical system, comprising:
- a laser light source configured to generate a multiplicity of light pulses;
- a first measuring unit configured to measure a variable that is characteristic of a speckle contrast of the light generated by the laser light source;
- a second measuring unit configured to measure a variable that is characteristic of a bandwidth of the light generated by the laser light source;
- and
- a control unit configured to control the laser light source so that, for a light pulse sequence generated by the laser light source, a time period between respectively successive light pulses varies across the light pulse sequence depending on output signals of the first measuring unit and the second measuring unit.
A method of operating an optical system comprising a laser light source configured to generate a multiplicity of light pulses and a controller configured so that, for a light pulse sequence generated by the laser light source, a time period between respectively successive light pulses varies across the light pulse sequence, the method comprising:
- varying the time period based on:
- measurement of a variable that is characteristic of a speckle contrast of the light generated by the laser light source;
- and a measurement of a respective bandwidth for at least one light pulse generated by the laser light source.
Dependencies are inferred from the claim text.