公开(公告)号：US20040264512A1

公开(公告)日：2004-12-30

申请号：US10606854

申请日：2003-06-26

Applicant: Northrop Grumman Corporation

Inventor： Jeffrey R. Hartlove ,  Mark E. Michaelian ,  Henry Shields ,  Samuel Talmadge ,  Steven W. Fornaca ,  Armando Martos

IPC: H01S003/30

CPC classification number: H05G2/003 ,  H05G2/008

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 translation: 采用低能量激光预脉冲和高能量激光主脉冲的EUV辐射源。 预脉冲在目标区域中产生弱等离子体，从而改善主激光脉冲的激光吸收以改善EUV辐射发射。 由预脉冲产生的局部目标蒸汽云中的碰撞会降低高能离子通量。 此外，低能量预脉冲在主脉冲之前20-200ns到达目标区域以获得最大输出强度。 预脉冲和主脉冲之间的定时可以降低到160ns以下，以提供更低的EUV辐射强度。 在一个实施例中，预脉冲通过具有适当的光束强度比的合适的分束器从主脉冲分离，并且主脉冲被延迟以在预脉冲之后到达目标区域。