Generating extreme ultraviolet radiation with nanoscale antennas

Patent metadata

Field	Value
Publication number	US-2020205276-A1
Application number	US-201816226565-A
Country	US
Kind code	A1
Filing date	Dec 19, 2018
Priority date	Dec 19, 2018
Publication date	Jun 25, 2020
Grant date	—

Abstract

A method for generating extreme ultraviolet (EUV) radiation employs an EUV apparatus, which comprises one or more sets of nanoscale antennas, designed for electromagnetic field enhancement. The one or more sets comprise, each, at least one pair of opposite antennas separated by a feedgap volume. First cations of same molecular entities are allowed to reach the feedgap volumes and the antennas are energized so as to perform one or more EUV radiation emission cycles, during which the first cations are further ionized via electromagnetic field intensities achieved in the feedgap volumes by optically exciting corresponding pairs of opposite antennas. Second cations are thus obtained, which have a higher charge state than the first cations, and are forced to radiatively decay, by electrically stimulating antenna pairs, whereby EUV radiation is generated and third cations are obtained, which have a lower charge state than the second cations.

First claim

What is claimed is:

1 . A method for generating extreme ultraviolet radiation, or EUV radiation, the method comprising:
providing an extreme ultraviolet radiation device, or EUV device, comprising one or more sets of nanoscale antennas designed for electromagnetic field enhancement, wherein the one or more sets comprise, each, at least one pair of opposite antennas separated by a gap defining a field enhancement volume, or FE volume, thereby forming one or more FE volumes, respectively; and allowing first cations of same molecular entities to reach the FE volumes and energizing the one or more sets of antennas, so as to perform one or more EUV radiation emission cycles, wherein:
the first cations are further ionized thanks to electromagnetic field intensities achieved in the FE volumes by optically exciting corresponding pairs of opposite antennas, whereby second cations are obtained, which have a higher charge state than the first cations; and
the second cations are forced to radiatively decay, by electrically stimulating antenna pairs of the one or more sets of antennas, whereby EUV radiation is generated and third cations are obtained, which have a lower charge state than the second cations.

2 . The method according to claim 1 , wherein
the first cations are allowed to reach the FE volumes and the one or more sets of antennas are energized so as to perform several EUV radiation emission cycles.

3 . The method according to claim 2 , wherein allowing the first cations to reach the FE volumes further comprises, during one of the cycles:
trapping the first cations in the FE volumes, thanks to electromagnetic field intensities and field gradients obtained in the FE volumes by optically exciting corresponding pairs of opposite antennas, whereby, subsequently, the first cations are further ionized and the second cations forced to decay while being trapped in the FE volumes.

4 . The method according to claim 3 , wherein
the method further comprises, during one of the cycles and after having forced the second cations to radiatively decay in said one of the cycles, releasing the third cations as they are still trapped in the FE volumes for them to be able to potentially reach any of the FE volumes, in view of a next one of the cycles.

5 . The method according to claim 3 , wherein:
the second cations are forced to radiatively decay so as to obtain third cations that have a same charge state as the first cations; and the method further comprises, during one of the cycles and after having forced the second cations to radiatively decay in said one of the cycles, maintaining the third cations in the FE volumes, in order to start a next one of the cycles.

6 . The method according to claim 1 , wherein
forcing the second cations to radiatively decay is achieved by applying or modifying a voltage bias between opposite antennas of at least one of the one or more sets, so as to tunnel one or more electrons through the corresponding FE volumes and thereby trigger a radiative decay of the second cations.

7 . The method according to claim 1 , wherein, during each of said one or more EUV radiation emission cycles:
optically exciting said corresponding pairs of opposite antennas is achieved by applying an optical pulse; and forcing the second cations to radiatively decay is achieved by applying or modifying a voltage bias between opposite antennas of two or more of the sets of antennas in a pulsed operating mode, whereby said voltage bias is simultaneously applied or modified across said two or more of the sets of antennas, at a predetermined time after having applied said optical pulse.

8 . The method according to claim 1 , wherein
the method further comprises generating the first cations and allowing the generated cations to reach a surface of the device, on which the one or more sets of antennas are arranged, in view of allowing the first cations to reach the FE volumes.

9 . The method according to claim 1 , wherein
the first cations comprise one of Xe p+ and Sn q+ ions, where 5≤p≤11 and 7≤q≤12.

10 . The method according to claim 1 , wherein
the first cations are further ionized by optically exciting pairs of opposite antennas so as for the charge state of the second cations obtained to exceed a charge state of the first cations by one charge unit, and the second cations are further forced to radiatively decay so as to obtain third cations that have a same charge state as the first cations.

11 . The method according to claim 10 , wherein
the first cations essentially comprise Xe 9+ ions, and during each of the cycles:
said corresponding pairs of opposite antennas are optically excited such that the second cations obtained essentially comprise Xe 10+ ions; and
the second cations are forced to radiatively decay essentially into Xe 9+ ions, so as to generate an EUV radiation having an average wavelength of 13.5 nm.

12 . The method according to claim 1 , wherein,
in the EUV device provided, the sets of nanoscale antennas comprise, each, two pairs of opposite antennas, wherein the two pairs define a single FE volume.

13 . The method according to claim 12 , wherein,
during each of the cycles, the first cations are further ionized by optically exciting antennas of a given one of said two pairs of antennas, whereas the second cations are forced to radiatively decay by electrically stimulating antennas of another one of said two pairs.

14 . The method according to claim 1 , wherein
the method further comprises directing EUV radiation generated during said one of the cycles to a given part of a UV-sensitive surface to pattern the latter, which completes one of the cycles.

15 . The method according to claim 14 , wherein
the one or more sets of antennas are energized so as to perform several EUV radiation emission cycles, and the method further comprises, upon completing said one of the cycles, moving the EUV device with respect to said UV-sensitive surface and directing EUV radiation generated during a next one of the cycles to another part of the UV-sensitive surface, in order to further pattern the latter.

16 . An extreme ultraviolet radiation apparatus, or EUV apparatus, wherein the apparatus comprises:
one or more sets of nanoscale antennas designed for electromagnetic field enhancement, wherein the one or more sets comprise, each, at least one pair of opposite antennas separated by a feedgap volume, thereby forming one or more FE volumes, respectively; a charging chamber system, configured to allow first cations of same molecular entities to reach the FE volumes; and a dual energization unit, coupled to the one or more sets of antennas and configured to energize such sets of antennas, so as to perform one or more EUV radiation emission cycles, wherein, in operation:
the first cations are further ionized thanks to electromagnetic field intensities achieved in the FE volumes by optically exciting corresponding pairs of opposite antennas, whereby second cations are obtained, which have a higher charge state than the first cations; and
the second cations are forced to radiatively decay, by electrically stimulating antenna pairs of such sets, whereby EUV radiation is generated and third cations are obtained, which have a lower charge state than the second cations.

17 . The EUV apparatus according to claim 16 , wherein:
the apparatus further comprises a support structure, the one or more sets of nanoscale antennas arranged on a surface of this support structure; and the support structure is designed so as to be essential

Assignees

• IBM

Inventors

• Loertscher Emanuel
• Giovannini Andrea

Classifications

• H05G2/007 Primary

  involving electric or magnetic fields in the process of plasma generation · CPC title

• B82Y15/00

  Nanotechnology for interacting, sensing or actuating, e.g. quantum dots as markers in protein assays or molecular motors · CPC title

• B82Y20/00

  Nanooptics, e.g. quantum optics or photonic crystals · CPC title

• H05G2/00 Primary

  Apparatus or processes specially adapted for producing X-rays, not involving X-ray tubes, e.g. involving generation of a plasma (X-ray lasers H01S4/00) · CPC title

• G03F7/70033

  by plasma extreme ultraviolet [EUV] sources · CPC title