Euv source generation method and related system

Patent metadata

Field	Value
Publication number	US-2018317309-A1
Application number	US-201815949543-A
Country	US
Kind code	A1
Filing date	Apr 10, 2018
Priority date	Apr 28, 2017
Publication date	Nov 1, 2018
Grant date	—

Abstract

A method and extreme ultraviolet (EUV) light source including a laser source configured to generate a first pre-pulse laser beam, a second pre-pulse laser beam, and a main pulse laser beam. In some embodiments, a droplet is irradiated within an extreme ultraviolet (EUV) vessel using the first pre-pulse laser beam to form a re-shaped droplet. In some examples, the droplet includes a tin droplet. In various embodiments, a seed plasma is then formed by irradiating the re-shaped droplet using the second pre-pulse laser beam. Thereafter, and in some cases, the seed plasma is heated by irradiating the seed plasma using the main pulse laser beam to generate EUV light.

First claim

What is claimed is:

1 . A method, comprising:
irradiating a droplet within an extreme ultraviolet (EUV) vessel using a first pre-pulse laser beam to form a re-shaped droplet; forming a seed plasma by irradiating the re-shaped droplet using a second pre-pulse laser beam; and heating the seed plasma by irradiating the seed plasma using a main pulse laser beam to generate EUV light.

2 . The method of claim 1 , wherein the droplet includes a tin droplet.

3 . The method of claim 1 , wherein the re-shaped droplet includes a disk, a dome, a cloud, or a mist.

4 . The method of claim 1 , wherein a time delay between the second pre-pulse laser beam and the main pulse laser beam is between about 10 and 100 nanoseconds.

5 . The method of claim 1 , wherein the second pre-pulse laser beam has a first wavelength, and wherein the main pulse has a second wavelength longer than the first wavelength.

6 . The method of claim 5 , wherein the first wavelength is equal to or less than 257 nanometers, and wherein the second wavelength is equal to or greater than 1.064 microns or 10.59 microns.

7 . The method of claim 1 , wherein a duration of the second pre-pulse laser beam is within a femtosecond to picosecond range.

8 . The method of claim 1 , wherein the second pre-pulse laser beam ignites a plasma to form the seed plasma.

9 . The method of claim 1 , wherein the second pre-pulse laser beam is implemented as one of a single pulse and a pulse train.

10 . The method of claim 1 , wherein formation of the seed plasma is controlled by tuning at least one of a power, a duration, and a delay of the second pre-pulse laser beam.

11 . The method of claim 1 , wherein each of the first pre-pulse laser beam, the second pre-pulse laser beam, and the main pulse laser beam are generated by the same or different laser sources.

12 . A method, comprising:
igniting a plasma within an extreme ultraviolet (EUV) vessel by irradiating a target within the EUV vessel using first laser pulse having a first wavelength; after irradiating the target using the first laser pulse and after a first delay time, heating the plasma by irradiating the plasma using a second laser pulse having a second wavelength longer than the first wavelength; and generating EUV light by the heated plasma.

13 . The method of claim 12 , further comprising:
prior to igniting the plasma, irradiating the target with a second laser pulse to re-shape the target; and after re-shaping the target and after a second delay time greater than the first delay time, igniting the plasma.

14 . The method of claim 12 , wherein the target includes a tin droplet.

15 . The method of claim 12 , wherein the first delay time is between about 10 and 100 nanoseconds.

16 . The method of claim 12 , wherein the first wavelength is about 257 nanometers, and wherein the second wavelength is about 10.59 microns.

17 . An extreme ultraviolet (EUV) light source, comprising:
a laser source configured to generate a first pre-pulse laser beam, a second pre-pulse laser beam, and a main pulse laser beam; an EUV vessel including a droplet generator that provides a tin droplet within the EUV vessel; and a collector having a first focus at an irradiation region within the EUV vessel and a second focus at an intermediate focus region; wherein the EUV light source is configured to irradiate the tin droplet at the irradiation region within the EUV vessel using the first pre-pulse laser beam to form a re-shaped droplet; wherein the EUV light source is configured to irradiate the re-shaped droplet using the second pre-pulse laser beam to form a seed plasma; and wherein the EUV light source is configured to heat the seed plasma using the main pulse laser beam to generate EUV light that is output from the EUV vessel through the intermediate focus region.

18 . The EUV light source of claim 17 , wherein a time delay between the second pre-pulse laser beam and the main pulse laser beam is between about 10 and 100 nanoseconds.

19 . The EUV light source of claim 17 , wherein the second pre-pulse laser beam has a first wavelength, and wherein the main pulse has a second wavelength longer than the first wavelength.

20 . The EUV light source of claim 17 , wherein the laser source includes a plurality of laser sources.

Assignees

• Taiwan Semiconductor Mfg Co Ltd

Inventors

• Chang Chun-Lin Louis
• Fu Tzung-Chi
• Liu Bo-Tsun
• Chen Li-Jui
• Cheng Po-Chung
• Yi Wei-Ting
• Chien Shang-Chieh

Classifications

• G03F7/70033 Primary

  by plasma extreme ultraviolet [EUV] sources · CPC title

• H05G2/005

  Electricity · mapped topic

• H05G2/008 Primary

  involving an energy-carrying beam in the process of plasma generation · CPC title

• H05G2/0035

  the material containing metals as principal radiation-generating components · CPC title

• H05G2/0084

  Control of the laser beam · CPC title