Laser system for target metrology and alteration in an EUV light source

Patent metadata

Field	Value
Publication number	US-12078934-B2
Application number	US-201917277027-A
Country	US
Kind code	B2
Filing date	Aug 12, 2019
Priority date	Sep 25, 2018
Publication date	Sep 3, 2024
Grant date	Sep 3, 2024

Abstract

Disclosed is a system and method for generating EUV radiation in which a laser is used in a multistage process to illuminate without altering a target material and then irradiate the target material to alter a target material with the illumination stage being used to determine the timing for firing during the irradiation stage or stages.

First claim

What is claimed is:

1. A method of using a radiation source including a laser to irradiate target material, the method comprising:
causing the laser to emit a metrology pulse;
using the target material to reflect at least a portion of the metrology pulse as a reflected portion of the metrology pulse;
determining a timing for the laser to emit an operational pulse based at least in part on whether the at least a portion of the reflected portion meets a predetermined criterion; and
causing the laser to emit the operational pulse at the timing as determined.

2. A method as in claim 1 wherein the predetermined criterion is the presence of any reflected metrology pulse.

3. A method as in claim 1 wherein the predetermined criterion is whether the magnitude of the irradiance of the reflected portion of the metrology pulse exceeds a predetermined value.

Assignees

• Asml Netherlands Bv

Inventors

• Rafac Robert Jay
• Fomenkov Igor Vladimirovich

Classifications

• H05G2/0084 Primary

  Control of the laser beam · CPC title

• G03F7/70558

  Dose control, i.e. achievement of a desired dose · CPC title

• G03F7/70041

  by pulsed sources, e.g. multiplexing, pulse duration, interval control or intensity control · CPC title

• G03F7/70033

  by plasma extreme ultraviolet [EUV] sources · CPC title

• G03F7/70025

  by lasers · CPC title