Deflection array apparatus for multi-electron beam system

Patent metadata

Field	Value
Publication number	US-10748739-B2
Application number	US-201816230325-A
Country	US
Kind code	B2
Filing date	Dec 21, 2018
Priority date	Oct 12, 2018
Publication date	Aug 18, 2020
Grant date	Aug 18, 2020

Abstract

An optical characterization system utilizing a micro-lens array (MLA) is provided. The system may include an electron source and a MLA including a micro-deflection array (MDA). The MDA may include an insulator substrate and a plurality of hexapole electrostatic deflectors disposed on the insulator substrate. The MDA may further include a plurality of voltage connecting lines configured to electrically couple the plurality of hexapole electrostatic deflectors to one or more voltage sources. The MDA may be configured to split a primary electron beam from the electron source into a plurality of primary electron beamlets. The system may be configured to focus the plurality of primary electron beamlets at a wafer plane.

First claim

What is claimed:

1. A system, comprising:
an electron source;
a micro-lens array (MLA) configured to receive one or more primary electron beams from the electron source, the micro-lens array including a micro-deflection array (MDA) comprising a plurality of hexapole electrostatic deflectors configured to eliminate third-order deflection aberrations, wherein the micro-deflection array is configured to split the one or more primary electron beams into a plurality of primary electron beamlets; and
projection optics configured to receive the plurality of primary electron beamlets and focus the plurality of primary electron beamlets onto a surface of a sample.

2. The system of claim 1 , wherein the micro-deflection array comprises:
an insulator substrate;
a plurality of hexapole electrostatic deflectors disposed on the insulator substrate, wherein each hexapole electrostatic deflector of the plurality of hexapole electrostatic deflectors comprises six deflection plates; and
a plurality of voltage connecting lines disposed on the insulator substrate configured to electrically couple the plurality of hexapole electrostatic deflectors to one or more voltage sources via a plurality of connecting pins, wherein the one or more voltage sources are configured to apply one or more focusing voltages to each hexapole electrostatic deflector of the plurality of hexapole electrostatic deflectors.

3. The system of claim 1 , further comprising a controller including one or more processors and a memory, wherein the one or more processors are configured to adjust the one or more focusing voltages applied to each hexapole electrostatic deflector of the plurality of hexapole electrostatic deflectors.

4. The system of claim 3 , wherein the one or more processors are further configured to adjust the one or more focusing voltages in order to individually adjust the position of each primary electron beamlet of the plurality of primary electron beamlets at the sample plane.

5. The system of claim 1 , further comprising an aperture configured to receive the primary electron beam from the electron source and direct the primary electron beam to the multi lens array (MLA).

6. The system of claim 1 , wherein the projection optics comprise a transfer lens and an objective lens.

7. The system of claim 1 , wherein the electron source comprises a thermal field emission (TFE) source.

8. The system of claim 1 , wherein the plurality of hexapole electrostatic deflectors comprise a plurality of dual-polarity hexapole electrostatic deflectors.

9. The system of claim 1 , wherein the plurality of hexapole electrostatic deflectors comprise a plurality of single-polarity hexapole electrostatic deflectors.

10. The system of claim 1 , wherein the plurality of hexapole electrostatic deflectors are arranged in a hexagonal configuration.

11. The system of claim 10 , wherein the number of hexapole electrostatic deflectors along a central column of the hexagonal configuration is defined by the term M c such that the total number of hexapole electrostatic deflectors MB tot in the micro-deflection array is defined by

MB
tot

=

1
4

⁢

(

1
+

3
⁢

M
C
2

)

.

12. The system of claim 1 ,
wherein a first deflection plate, a third deflection plate, and a fifth deflection plate of each hexapole electrostatic deflector of the plurality of hexapole electrostatic deflectors are applied with a first focusing voltage, and
wherein a second deflection plate, a fourth deflection plate, and a sixth deflection plate of each hexapole electrostatic deflector of the plurality of hexapole electrostatic deflectors are applied with a second focusing voltage.

13. The system of claim 1 ,
wherein each deflection plate of the six deflection plates are separated by a gap angle δ, and
wherein a second deflection plate, a third deflection plate, a fifth deflection plate, and a sixth deflection plate are defined by a plate angle β, such that β+δ=20°.

14. The system of claim 1 , wherein each hexapole electrostatic deflector of the plurality of hexapole electrostatic deflectors is coupled to the one or more voltage sources with a single voltage connecting line.

15. The system of claim 1 , wherein each hexapole electrostatic deflector of the plurality of hexapole electrostatic deflectors comprises a micro Einzel lens.

16. A micro-deflection array, comprising:
an insulator substrate;
a plurality of hexapole electrostatic deflectors disposed on the insulator substrate, wherein each hexapole electrostatic deflector of the plurality of hexapole electrostatic deflectors comprises six deflection plates configured to eliminate third-order deflection aberrations; and
a plurality of voltage connecting lines disposed on the insulator substrate configured to electrically couple the plurality of hexapole electrostatic deflectors to one or more voltage sources via a plurality of connecting pins, wherein the one or more voltage sources are configured to apply one or more focusing voltages to each hexapole electrostatic deflector of the plurality of hexapole electrostatic deflectors.

17. The micro-deflection array of claim 16 , wherein the micro-deflection array is configured to receive one or more primary electron beams from an electron source and split the one or more primary electron beams into a plurality of primary electron beam lets.

18. The micro-deflection array of claim 17 , wherein the micro-deflection array is configured to individually adjust the position of each primary electron beam let of the plurality of primary electron beam lets.

19. The micro-deflection array of claim 16 , wherein the plurality of hexapole electrostatic deflectors comprise a plurality of dual-polarity hexapole electrostatic deflectors.

20. The micro-deflection array of claim 16 , wherein the plurality of hexapole electrostatic deflectors comprise a plurality of single-polarity hexapole electrostatic deflectors.

21. The micro-deflection array of claim 16 , wherein the plurality of hexapole electrostatic deflectors are arranged in a hexagonal configuration.

22. The micro-deflection array of claim 21 , wherein the number of hexapole electrostatic deflectors along a central column of the hexagonal configuration is defined by the term M c such that the total number of hexapole electrostatic deflectors MB tot in the micro-deflection array is defined by

MB
tot

=

1
4

⁢

(

1
+

Assignees

• Kla Tencor Corp

Inventors

• Jiang Xinrong
• Sears Christopher

Classifications

• H01J37/3177

  Multi-beam, e.g. fly's eye, comb probe · CPC title

• H01J37/304 Primary

  Controlling tubes by information coming from the objects {or from the beam}, e.g. correction signals · CPC title

• H01J37/3005

  Observing the objects or the point of impact on the object · CPC title

• H01J37/045

  Beam blanking or chopping, i.e. arrangements for momentarily interrupting exposure to the discharge · CPC title

• H01J2237/1202

  Associated circuits · CPC title