Laser-produced plasma EUV source with reduced debris generation utilizing predetermined non-thermal laser ablation

摘要

A method and apparatus for generating extreme ultraviolet (EUV) light is disclosed. The method may comprise non-thermally ablating a target material utilizing a first laser beam. The first laser beam may be configured for ejecting a portion of the target material in a non-thermal manner to create a plume. The method may further comprise irradiating the plume utilizing a second laser beam to produce a high-temperature plasma for EUV radiation.

主权项

1. A method for generating extreme ultraviolet (EUV) light, the method comprising:
supporting a target material on a support substrate; providing a first laser beam for ablating a surface of the target material to separate and eject a portion of the target material away from the surface in a non-thermal manner without heat dissipation, the first laser beam having a pulse duration multiple orders of magnitude faster than a time of heat dissipation of absorbed laser energy by thermal conduction of the target material, the first laser beam having a wavelength in a range of ultraviolet wavelengths, wherein the pulse duration, the wavelength, and an intensity of the first laser beam are tuned so that when the target material is ablated by the first laser beam, a penetration depth of the ablation is near that of an optical absorption depth of the target material to reduce thermal damage to the target material and to induce a rapid phase change of the portion of the target material ejected away from the surface of the target material when the target material is ablated by the first laser beam; calculating an ablation rate based on the pulse duration of the first laser beam and the wavelength of the first laser beam; determining a number of pulses needed from the first laser beam to produce an amount of material necessary to form a mass-limited target plume based on the ablation rate; determining an angle of incidence between the first laser beam and the surface of the target material to shape the mass-limited target plume to increase collection efficiency and reduce debris generation when the mass-limited target plume is irradiated by a second laser beam; non-thermally ablating the surface of the target material utilizing the first laser beam according to the number of pulses determined to create the mass-limited target plume ejected from the surface of the target material without heat dissipation; and irradiating the mass-limited target plume utilizing the second laser beam to produce a high-temperature plasma for EUV radiation.