Light source, EUV lithography system, and method for generating EUV radiation

Patent metadata

Field	Value
Publication number	US-11333983-B2
Application number	US-202017077410-A
Country	US
Kind code	B2
Filing date	Oct 22, 2020
Priority date	Sep 28, 2017
Publication date	May 17, 2022
Grant date	May 17, 2022

Abstract

A light source for EUV is provided. The light source includes a target droplet generator, a laser generator, and a controller. The target droplet generator is configured to provide target droplets to a source vessel. The laser generator is configured to provide first laser pulses according to a control signal to irradiate the target droplets in the source vessel. The controller is configured to provide the control signal according to at least two of process parameters including temperature of the source vessel, droplet positions of the target droplets, and beam sizes and focal points of the first laser pulses. When the average value or the standard deviation of the temperature of the source vessel and the droplet positions of the target droplets exceed the predetermined range, the controller is configured to provide the control signal to the laser generator to stop providing the first laser pulses.

First claim

What is claimed is:

1. A light source for extreme ultraviolet (EUV) radiation, comprising:
a target droplet generator configured to provide a plurality of target droplets to a source vessel;
a laser generator configured to provide a plurality of first laser pulses according to a control signal to irradiate the target droplets in the source vessel, so as to generate plasma as the EUV radiation; and
a controller configured to provide the control signal according to at least two of process parameters including a temperature of the source vessel, droplet positions of the target droplets, beam sizes of the first laser pulses, and focal points of the first laser pulses;
wherein when an average value or a standard deviation of the temperature of the source vessel exceeds a first predetermined range and an average value or a standard deviation of the droplet positions of the target droplets exceeds a second predetermined range, the controller is configured to provide the control signal to the laser generator, so as to stop providing the first laser pulses.

2. The light source as claimed in claim 1 , wherein when an average value or a standard deviation of one of the process parameters other than the temperature of the source vessel and the droplet positions of the target droplets exceeds a third predetermined range, the controller is further configured to provide the control signal to the laser generator, so as to stop providing the first laser pulses.

3. The light source as claimed in claim 1 , wherein when the average value or the standard deviation of the temperature of the source vessel does not exceed the first predetermined range and/or the average value or the standard deviation of the droplet positions of the target droplets does not exceed the second predetermined range, the controller is further configured to provide the control signal to the laser generator, so as to continue providing the first laser pulses.

4. The light source as claimed in claim 1 , wherein the controller is further configured to perform an arithmetic calculation on one of the process parameters including first derivatives of the droplet positions of the target droplets, standard deviation or average value of the beam sizes of the first laser pulses, standard deviation or average value of the focal points of the first laser pulses, or first derivatives of the focal points of the first laser pulses.

5. The light source as claimed in claim 1 , wherein the laser generator comprises:
a first laser source configured to provide a plurality of second laser pulses to irradiate the target droplets, so as to generate a plurality of target plumes; and
a second laser source configured to provide the first laser pulses to irradiate the target plumes in response to the control signal, so as to generate the plasma.

6. The light source as claimed in claim 1 , wherein the laser generator comprises:
a first laser source configured to provide a plurality of second laser pulses to irradiate the target droplets in response to the control signal, so as to generate a plurality of target plumes; and
a second laser source configured to provide the first laser pulses to irradiate the target plumes in response to the control signal, so as to generate the plasma.

7. An extreme ultraviolet (EUV) lithography system for performing a lithography exposing process, comprising:
an EUV scanner; and
a light source configured to provide EUV radiation to the EUV scanner in response to a control signal, wherein the light source comprises:
a collector configured to collect the EUV radiation and direct the EUV radiation to the EUV scanner;
a target droplet generator configured to provide a plurality of target droplets to a source vessel;
a laser generator configured to provide a plurality of first laser pulses according to the control signal to irradiate the target droplets in the source vessel, so as to generate plasma as the EUV radiation; and
a controller configured to provide the control signal to the laser generator to stop providing the first laser pulses, and to provide the control signal to the EUV scanner to suspend the lithography exposing process according to at least two of process parameters including a temperature of the source vessel, droplet positions of the target droplets, beam sizes of the first laser pulses, and focal points of the first laser pulses;
wherein the controller is configured to provide the control signal to the EUV scanner to suspend the lithography exposing process when an average value or a standard deviation of the beam sizes of the first laser pulses exceeds a first predetermined range and an average value or a standard deviation of the droplet positions of the target droplets exceeds a second predetermined range.

8. The EUV lithography system as claimed in claim 7 , wherein the light source further comprises:
a thermal sensor configured to measure the temperature of the source vessel and to provide the measured temperature to the controller;
a droplet detector configured to measure the droplet positions of the target droplets and to provide the measured droplet positions to the controller; and
a laser meter configured to measure the beam sizes and the focal points of the first laser pulses and to provide the measured beam sizes and the measured focal points to the controller.

9. The EUV lithography system as claimed in claim 7 , wherein when the control signal indicates that an average value or a standard deviation of one of the process parameters other than the beam sizes of the first laser pulses and the droplet positions of the target droplets exceeds a third predetermined range, the laser generator is configured to stop providing the first laser pulses, so as to stop providing the EUV radiation to the EUV scanner.

10. The EUV lithography system as claimed in claim 7 , wherein when the control signal indicates that the average value or the standard deviation of the beam sizes of the first laser pulses does not exceed the first predetermined range and/or the average value or the standard deviation of the droplet positions of the target droplets does not exceed the second predetermined range, the laser generator is further configured to continue providing the first laser pulses, so as to provide the EUV radiation to the EUV scanner.

11. The EUV lithography system as claimed in claim 7 , wherein the laser generator comprises:
a first laser source configured to provide a plurality of second laser pulses to irradiate the target droplets, so as to generate a plurality of target plumes; and
a second laser source configured to provide the first laser pulses to irradiate the target plumes in response to the control signal, so as to generate the plasma.

12. The EUV lithography system as claimed in claim 7 , wherein the laser generator comprises:
a first laser source configured to provide a plurality of second laser pulses to irradiate the target droplets in response to the control signal, so as to generate a plurality of target plumes; and
a second laser source configured to provide the first laser pulses to irradiate the target plumes in response to the control signal, so as to generate the plasma.

13. The EUV lithography system as claimed in claim 7 , wherein the EUV scanner is configured to illuminate a patterning mask with the EUV radiation in response to the control signal, so as to provide a patterned beam and project the patterned beam onto a semiconductor substrate in the lithography exposing process.

14. A method for generating extreme ultraviolet (EUV) radiation, comprising:
providing a plurality of target droplets to a source vessel;
measuring

Assignees

• Taiwan Semiconductor Mfg Co Ltd
• Taiwan Semiconductor Manfacturing Company Ltd

Inventors

• Yang Chi
• Chen Ssu-Yu
• Chien Shang-Chieh
• Hsieh Chieh
• Fu Tzung-Chi
• Liu Bo-Tsun
• Chen Li-Jui
• Cheng Po-Chung

Classifications

• H05G2/0084

  Control of the laser beam · CPC title

• G03F7/70033 Primary

  by plasma extreme ultraviolet [EUV] sources · CPC title

• G03F7/70025

  by lasers · CPC title

• G03F7/70533

  Controlling abnormal operating mode, e.g. taking account of waiting time, decision to rework or rework flow · CPC title

• G03F7/2004 Primary

  characterised by the use of a particular light source, e.g. fluorescent lamps or deep UV light · CPC title