Described herein is an improved target for use in a pulsed induced plasma X-ray lithography system. The target is formed as a disk shaped base having a series of concentric grooves formed on the side thereof incident to the focused laser beam. A plurality of small holes are fabricated through the base to the facing wall of the groove against which the laser beam is focused and a film, of a polyimide or silicon nitride material, covers the hole. A thin layer of metal target material is then placed on the film aligned with each hole. The thickness of the metal is selected to be sufficient to allow the complete ablation of the material during the existence of the X-ray emitting plasma. In this manner, a minimal amount of debris, either in the form of molten droplets or evaporated metal material, will be generated. The angle of the incident, or facing, side of the grooves is selected to be at an angle so that both the laser beam optical elements and the X-ray mask are positioned in an area where few, if any, molten droplets of debris are emitted. Such an angle may be 45.degree. with respect to the plane in which the target substrate is moved while placing different target areas in incident with the laser beam. Such an target also allows the angle at which the laser beam is focused at the target to be approximately 65.degree. from the alignment of the focal spot on the target and the vertical line to the mask. This angle, in turn, allows a slower lens and less optical coating to be used on the optical elements beyond the lens.

In a laser plasma X-ray device for use in generating X-rays by bombarding a target material by a pulsed laser beam, the target material is selected from materials which are in a gas phase at the room temperature and which are cooled in a selected one of liquid and solid phases. Such a selected phase of the target material is continuously supplied to a focal point of the pulsed laser beam to be subjected to bombardment and to generate the X-rays. On generation of the X-rays, the target material is rendered into the gas phase to be recycled into the selected phase. The X-rays are guided outside of the chamber through an X-ray gate unit opened in synchronism with a repetition frequency of the pulsed laser beam.

A solid target (11) is formed with a cavity (12). The inner wall of the solid target at the cavity is ablated by ablation pulsed laser beams (13). The solid target is left standing until a highly densified portion (15) of a vaporized substance (14) is formed in the space within the cavity (14), and the highly densified portion (15) is then irradiated with heating pulsed laser beams (17), thereby forming high-temperature plasma (18) for generating radiation rays (19). As a result, good-quality radiation rays accompanied by a minimal amount of debris can be generated.

Disclosed herein is an X-ray lithography system having a long life target. The life of the conventional target in X-ray generating systems for use in X-ray lithography systems is increased by providing means by which a single laser pulse can be provided to the same spot a plurality of times. In addition, new target designs are provided which are mechanically moved to allow laser pulses to be provided to adjacent points over a large surface area. One type of target is a cylindrical drum which is helically rotated to allow the laser pulse to intersect at all points along the helix of the drum. A second type of long life target is a long continuous strip in which a strip is moved from a feed reel to a take-up reel. The strip may be within a cassette.

A high repetition-rate laser plasma target source system wherein ice crystals are irradiated by a laser and lithography system. The target source system comprises in a preferred embodiment a liquid tank source and freezer means which freezes microscopic particles into crystal shapes which are projected by a nozzle jet from a high repetition rate liquid-droplet injector into the path of a flashing laser beam, which results in producing soft x-rays of approximately 11.7 nm and 13 nm. Uncollected and unshot target crystals are collected and reliquified by a heater source in order to be recycled back to the liquid tank source. Optionally an auxiliary source and detector system can be used to allow for instantaneous triggering of the laser beam. The target source system can be incorporated into well known EUV lithography systems for the production of wafer chips.