Abstract: An EUV radiation source that employs a low energy laser pre-pulse and a high energy laser main pulse. The pre-pulse generates a weak plasma in the target area that improves laser absorption of the main laser pulse to improve EUV radiation emissions. High energy ion flux is reduced by collisions in the localized target vapor cloud generated by the pre-pulse. Also, the low energy pre-pulse arrives at the target area 20–200 ns before the main pulse for maximum output intensity. The timing between the pre-pulse and the main pulse can be reduced below 160 ns to provide a lower intensity of the EUV radiation. In one embodiment, the pre-pulse is split from the main pulse by a suitable beam splitter having the proper beam intensity ratio, and the main pulse is delayed to arrive at the target area after the pre-pulse.

Abstract: An EUV radiation source (40) that includes a nozzle (42) positioned a far enough distance away from a target region (50) so that EUV radiation (56) generated at the target region (50) by a laser beam (54) impinging a target stream (46) emitted from the nozzle (42) is not significantly absorbed by target vapor proximate the nozzle (42). Also, the EUV radiation (56) does not significantly erode the nozzle (42) and contaminate source optics (34). In one embodiment, the nozzle (42) is more than 10 cm away from the target region (50).

Abstract: A laser-plasma EUV radiation source (10) that employs one or more approaches for preventing vaporization of material from a nozzle assembly (40) of the source (10) by electrical discharge from the plasma (30). The first approach includes employing an electrically isolating nozzle end, such as a glass capillary tube (46). The tube (46) extends beyond all of the conductive surfaces of the nozzle assembly (40) by a suitable distance so that the pressure around the closest conducting portion of the nozzle assembly (40) is low enough not to support arcing. A second approach includes providing electrical isolation of the conductive portions of the source (40) from the vacuum chamber wall. A third approach includes applying a bias potential (52) to the nozzle assembly (40) to raise the potential of the nozzle assembly (40) to the potential of the arc.

Abstract: An EUV radiation source that employs a low energy laser pre-pulse and a high energy laser main pulse. The pre-pulse generates a weak plasma in the target area that improves laser absorption of the main laser pulse to improve EUV radiation emissions. High energy ion flux is reduced by collisions in the localized target vapor cloud generated by the pre-pulse. Also, the low energy pre-pulse arrives at the target area 20-200 ns before the main pulse for maximum output intensity. The timing between the pre-pulse and the main pulse can be reduced below 160 ns to provide a lower intensity of the EUV radiation. In one embodiment, the pre-pulse is split from the main pulse by a suitable beam splitter having the proper beam intensity ratio, and the main pulse is delayed to arrive at the target area after the pre-pulse.

Abstract: An EUV radiation source (40) that includes a nozzle (42) positioned a far enough distance away from a target region (50) so that EUV radiation (56) generated at the target region (50) by a laser beam (54) impinging a target stream (46) emitted from the nozzle (42) is not significantly absorbed by target vapor proximate the nozzle (42). Also, the EUV radiation (56) does not significantly erode the nozzle (42) and contaminate source optics (34). In one embodiment, the nozzle (42) is more than 10 cm away from the target region (50).

Abstract: An EUV radiation source that creates a stable solid filament target. The source includes a nozzle assembly having a condenser chamber for cryogenically cooling a gaseous target material into a liquid state. The liquid target material is filtered by a filter and sent to a holding chamber under pressure. The holding chamber allows entrained gas bubbles in the target material to be condensed into liquid prior to the filament target being emitted from the nozzle assembly. The target material is forced through a nozzle outlet tube to be emitted from the nozzle assembly as a liquid target stream. A thermal shield is provided around the outlet tube to maintain the liquid target material in the cryogenic state. The liquid target stream freezes and is vaporized by a laser beam from a laser source to generate the EUV radiation.

Abstract: An EUV radiation source (50) that employs a steering device (74) for steering a stream (66) of droplets (68) generated by a droplet generator (52) so that the droplet (68) are directed towards a target location (76) to be vaporized by a laser beam (78). The direction of the stream (66) of droplets (68) is sensed by a sensing device (84). The sensing device (84) sends a signal to an actuator (88) that controls the orientation of the steering device (74) so that the droplets (68) are directed to the target location (76).

Abstract: A laser-plasma EUV radiation source (10) that employs one or more approaches for preventing vaporization of material from a nozzle assembly (40) of the source (10) by electrical discharge from the plasma (30). The first approach includes employing an electrically isolating nozzle end, such as a glass capillary tube (46). The tube (46) extends beyond all of the conductive surfaces of the nozzle assembly (40) by a suitable distance so that the pressure around the closest conducting portion of the nozzle assembly (40) is low enough not to support arcing. A second approach includes providing electrical isolation of the conductive portions of the source (40) from the vacuum chamber wall. A third approach includes applying a bias potential (52) to the nozzle assembly (40) to raise the potential of the nozzle assembly (40) to the potential of the arc.

Abstract: An EUV radiation source that creates a stable solid filament target. The source includes a nozzle assembly having a condenser chamber for cryogenically cooling a gaseous target material into a liquid state. The liquid target material is filtered by a filter and sent to a holding chamber under pressure. The holding chamber allows entrained gas bubbles in the target material to be condensed into liquid prior to the filament target being emitted from the nozzle assembly. The target material is forced through a nozzle outlet tube to be emitted from the nozzle assembly as a liquid target stream. A thermal shield is provided around the outlet tube to maintain the liquid target material in the cryogenic state. The liquid target stream freezes and is vaporized by a laser beam from a laser source to generate the EUV radiation.

Abstract: An EUV radiation source (50) that employs a steering device (74) for steering a stream (66) of droplets (68) generated by a droplet generator (52) so that the droplet (68) are directed towards a target location (76) to be vaporized by a laser beam (78). The direction of the stream (66) of droplets (68) is sensed by a sensing device (84). The sensing device (84) sends a signal to an actuator (88) that controls the orientation of the steering device (74) so that the droplets (68) are directed to the target location (76).

Abstract: The invention relates to an extreme ultraviolet lithography system that utilizes thin film protective coatings to protect a plurality of hardware components, located near a laser-produced light source, from the erosive effects of energetic particles emitted by the laser-produced light source.

Abstract: A photographic camera (10) that generates still photographs or images of a scene by detecting millimeter-wave radiation (16). The camera (10) includes an imaging lens (14) that collects the millimeter-wave radiation (16) and focuses the radiation on a plurality of receiver modules (32) positioned in the focal point of the lens (14) where each receiver module (32) includes a plurality of direct detection millimeter-wave receivers (36). In one embodiment, the plurality of receiver modules (32) are mounted on a single sensor card (28), where the receiver modules (32) on the card (28) are aligned in one direction. Each receiver (36) includes detector circuitry that detects the radiation of a pixel in the scene. Electrical signals from the receiver modules (32) are sent to a processing unit (38) on the sensor card (28). In one embodiment, the radiation (16) collected by the lens (14) is directed to a scanning mirror (18) that scans across the scene at a predetermined rate to generate the entire image.

Abstract: A method of calibrating gains and offsets for a two-dimensional detector array 10 comprising individual detector elements 14, including: (a) focusing a first incoming image signal at a first power level onto the detector array 10; (b) reading the corresponding electrical signals from the detector elements 14 as a first image frame at the first power level; (c) for each detector element 14, translating the first incoming image signal by a detector element distance onto an adjacent detector element; (d) reading the corresponding electrical signal from the detector elements 14 as a second image frame at the first power level; (e) focusing a second incoming image signal at a second power level onto the detector array 10; (f) reading the corresponding electrical signals from the detector elements 14 as a first image frame at the second power level; (g) for each detector element 14, translating the second incoming image signal by a detector element distance onto an adjacent detector element; (h) reading the corresp