Lithographic method

Patent metadata

Field	Value
Publication number	US-2016147161-A1
Application number	US-201414900110-A
Country	US
Kind code	A1
Filing date	Jun 17, 2014
Priority date	Jun 18, 2013
Publication date	May 26, 2016
Grant date	—

Abstract

A method of patterning lithographic substrates that includes using a free electron laser to generate EUV radiation and delivering the EUV radiation to a lithographic apparatus which projects the EUV radiation onto lithographic substrates. The method further includes reducing fluctuations in the power of EUV radiation delivered to the lithographic substrates by using a feedback-based control loop to monitor the free electron laser and adjust operation of the free electron laser accordingly, and applying variable attenuation to EUV radiation that has been output by the free electron laser in order to further control the power of EUV radiation delivered to the lithographic apparatus.

First claim

1 . A method of patterning lithographic substrates, the method comprising using a free electron laser to generate EUV radiation and delivering the EUV radiation to a lithographic apparatus which projects the EUV radiation onto lithographic substrates, wherein the method further comprises reducing fluctuations in the power of EUV radiation delivered to the lithographic substrates by using a feedback-based control loop to monitor the free electron laser and adjust operation of the free electron laser accordingly, and wherein the method further comprises applying variable attenuation to EUV radiation that has been output by the free electron laser in order to further control the power of EUV radiation delivered to the lithographic apparatus.

2 .- 7 . (canceled)

8 . The method of claim 1 , wherein the lithographic apparatus is one of a plurality of lithographic apparatus which receives the EUV radiation.

9 . The method of claim 8 , wherein the variable attenuation of the EUV radiation is independently controllable for each of the lithographic apparatus.

10 . The method of claim 1 , wherein the variable attenuation is controlled by a second feedback-based control loop.

11 . The method of claim 10 , wherein the second feedback-based control loop operates at a frequency of 1 kHz or less.

12 . The method of claim 10 , wherein the second feedback-based control loop uses EUV radiation intensity as measured by a sensor located in the lithographic apparatus, the sensor being located before a projection system of the lithographic apparatus.

13 . The method of claim 10 , wherein the second feedback-based control loop uses EUV radiation intensity as measured by a sensor located in the lithographic apparatus, the sensor being located after a projection system of the lithographic apparatus.

14 .- 20 . (canceled)

21 . A lithographic system comprising a free electron laser configured to generate EUV radiation and a lithographic apparatus configured to project the EUV radiation onto lithographic substrates, wherein the apparatus further comprises a feedback-based control loop comprising a sensor configured to monitor the EUV radiation output by the free electron laser and a controller configured to receive an output from the sensor and to adjust operation of the free electron laser accordingly, and wherein the apparatus further comprises an attenuator configured to apply variable attenuation to EUV radiation that has been output by the free electron laser in order to further control the power of EUV radiation delivered to the lithographic apparatus.

22 .- 27 . (canceled)

28 . The lithographic system of claim 21 , wherein the lithographic apparatus is one of a plurality of lithographic apparatus which receives the EUV radiation.

29 . The lithographic system of claim 28 , wherein an attenuator is provided for each lithographic apparatus, the attenuators being independently controllable for each of the lithographic apparatus.

30 . The lithographic system of claim 21 , wherein the variable attenuation is controlled by a second feedback-based control loop.

31 . The lithographic system of claim 30 , wherein the second feedback-based control loop operates at a frequency of 1 kHz or less.

32 . The lithographic system of claim 30 , wherein the second feedback-based control loop comprises a sensor configured to measure EUV radiation intensity in the lithographic apparatus.

33 . The lithographic system of claim 32 , wherein the sensor is located before a projection system of the lithographic apparatus.

34 . The lithographic system of claim 32 , wherein the sensor is located after a projection system of the lithographic apparatus.

35 .- 202 . (canceled)

Assignees

• Asml Netherlands Bv

Inventors

• Nikipelov Andrey Alexandrovich
• Frijns Olav Waldemar Vladimir
• De Vries Gosse Charles
• Loopstra Erik Roelof
• Banine Vadim Yevgenyevich
• De Jager Pieter Willem Herman
• Donker Rilpho Ludovicus
• Nienhuys Han-Kwang
• Kruizinga Borgert
• Engelen Wouter Joep
• Luiten Otger Jan
• Akkermans Johannes Antonius Gerardus
• Grimminck Leonardus Adrianus Gerardus
• Litvinenko Vladimir

Classifications

• H05H9/048

  Lepton LINACS · CPC title

• H05H2007/041

  for beam bunching, e.g. undulators · CPC title

• H05H7/18

  Cavities; Resonators {(travelling-wave tubes H01J23/18; hyperfrequency cavities in general H01P7/04, H01P7/06)} · CPC title

• G01J1/0418

  using attenuators · CPC title

• G03F7/7085

  Detection arrangement, e.g. detectors of apparatus alignment possibly mounted on wafers, exposure dose, photo-cleaning flux, stray light, thermal load · CPC title