Ushio Denki Kabushiki Kaisha

Mohamad Hussein El-Husseini

Sven Probst

Takahiro Hiraoka

A method for triggering a resonant charging circuit for a device for generating short-wavelength radiation based on discharge plasma is described. Switching times of the resonant charging circuit are determined in a non-time-critical method segment by simulation and are stored to be repeatedly retrievable. Measurement values of the resonant charging circuit are determined in real time in a time-critical method segment. At least one second switching time (t) at which a discharging switch of the resonant charging circuit is triggered in order to supply at a firing time (t) a discharge voltage (U), and the firing time (t) are calculated. The device has a first input unit, a first simulation unit, a first regression unit, a first measurement value unit, a first evaluation unit and a control unit for triggering a discharging switch of the resonant charging circuit.

Method for controlling an EUV source

A method for controlling a discharge plasma-based radiation source for stabilizing a radiation dose emitted in a pulsed manner is disclosed. A calibration function is determined from a relationship between values of an input quantity and values of an operating parameter of the source by applying different values of the input quantity to the source. Reference value selected from the values of the operating parameter is brought about during a pulse of the source. The value of a test quantity is acquired at each pulse. Any quantity influencing the emitted radiation dose can be selected as test quantity. A statistical value is formed from a defined quantity of values of the test quantity. A deviation between the statistical value and the reference value is determined. A result of a comparison of the deviation with a predefined tolerance range determines whether the method is repeated.

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Milmort, Belgium

Mohamad Hussein El-Husseini