Apparatus for and method of source material delivery in a laser produced plasma euv light source

A device comprising:

• a chamber;
• a source material delivery system configured to deliver source material to within the chamber;
• and
• a shroud arranged between the source material delivery system and an irradiation region within the chamber, the shroud having a first portion and a second portion which is movable with respect to the first portion between a first position in which the second portion engages the first portion to form a seal between the first portion and the second portion and a second position in which the second portion is at least partially spaced away from the first portion.

A device comprising:

• a chamber;
• a collector mirror arranged in the chamber;
• a source material delivery system configured to deliver source material to within the chamber, the source material delivery system having a first state in which the source material delivery system delivers source material along a first path to an irradiation region within the chamber and a second state in which the source material delivery system delivers source material along a second path further from the collector than the first path;
• a shroud arranged between the source material delivery system and the irradiation region, the shroud having a first portion and a second portion which is movable with respect to the first portion between a first position in which the second portion engages the first portion to form a seal between the first portion and the second portion and a second position in which the second portion is at least partially spaced away from the first portion;
• and
• a control system coupled to the source material delivery system and to the shroud for establishing a first condition in which the second portion is in the first position and the source material delivery system is in the first state and a second condition in which the second portion is in the second position and the source material delivery system is in the second state.

A method comprising the steps of:

• providing a shroud between a source material delivery system and an irradiation region within a chamber, the shroud having a first portion and a second portion which is movable with respect to the first portion between a first position in which the second portion engages the first portion to form a seal between the first portion and the second portion and a second position in which the second portion is at least partially spaced away from the first portion;
• placing the shroud in the second position;
• orienting the source material delivery system to cause source material to be delivered other than directly towards the irradiation region in the chamber;
• operating the source material delivery system;
• determining whether a path travelled by the source material has become predictable;
• redirecting the source material delivery system to cause source material to be delivered directly towards the irradiation region if the determination is affirmative;
• and
• placing the shroud in the first position.

A method comprising the steps of:

• providing a shroud between a source material delivery system and an irradiation region within a chamber, the shroud having a first portion and a second portion which is movable with respect to the first portion between a first position in which the second portion engages the first portion to form a seal between the first portion and the second portion and a second position in which the second portion is at least partially spaced away from the first portion;
• placing the shroud in the second position;
• orienting the source material delivery system to cause source material to be delivered other than directly towards the irradiation region in the chamber;
• and
• shutting down the source material delivery system.