Methods and devices for examining an electrically charged specimen surface

Patent metadata

Field	Value
Publication number	US-11170970-B2
Application number	US-201816106083-A
Country	US
Kind code	B2
Filing date	Aug 21, 2018
Priority date	Sep 1, 2015
Publication date	Nov 9, 2021
Grant date	Nov 9, 2021

Abstract

A method for examining a specimen surface with a probe of a scanning probe microscope, the specimen surface having an electrical potential distribution. The method includes (a) determining the electrical potential distribution of at least one first partial region of the specimen surface; and (b) modifying the electrical potential distribution in the at least one first partial region of the specimen surface and/or modifying an electrical potential of the probe of the scanning probe microscope before scanning at least one second partial region of the specimen surface.

First claim

What is claimed is:

1. A method for examining a specimen surface with a charged particle beam of a scanning particle microscope, the specimen surface having an electrical potential distribution of an electrostatic charge, the method comprising the steps of:
determining the electrical potential distribution of the electrostatic charge of at least one first partial local region of the specimen surface; and
correcting at least one setting of the scanning particle microscope on the basis of a pixel-based determination of the potential distribution of the electrostatic charge to process at least one second partial local region of the specimen surface with the charged particle beam, the at least one first partial local region of the specimen surface containing the at least one second partial local region of the specimen surface.

2. The method according to claim 1 , the at least one setting of the scanning particle microscope comprising: altering a magnification, altering a focus, altering a stigmator, altering an acceleration voltage, altering a beam displacement, adjusting a position of a particle source of the scanning particle microscope and/or altering a stop.

3. The method according to claim 1 , the processing of the at least one second partial local region of the specimen surface comprising providing at least one of: at least one etching gas for etching material from the at least one second partial local region of the specimen or at least one precursor gas for depositing material in the at least one second partial local region of the specimen surface.

4. The method according to claim 1 , wherein the correcting the at least one setting of the scanning particle microscope is performed pixel by pixel.

5. The method according to claim 1 , the determination of the electrical potential distribution of the electrostatic charge of the at least one first partial local region of the specimen surface comprising analyzing an energy distribution of secondary electrons of the at least one first partial local region of the specimen surface by use of a spectrometer, the secondary electrons being generated during the scanning of the at least one first partial local region of the specimen surface with a charged particle beam of a scanning particle microscope.

6. The method according to claim 5 , the determination of the electrical potential distribution of the electrostatic charge of the at least one first partial local region of the specimen surface comprising determining a displacement of the energy distribution of the secondary electrons.

7. The method according to claim 6 , the determination of the displacement of the energy distribution of the secondary electrons taking place with respect to a specimen surface that has substantially no electrical potential.

8. The method according to claim 6 , the determination of the displacement of the energy distribution of the secondary electrons comprising applying an electrical field over the at least one first partial local region of the specimen surface.

9. The method according to claim 6 , the determination of the electrical potential distribution of the electrostatic charge of the at least one first partial local region of the specimen surface comprising determining a maximum of the energy distribution of back-scattered electrons in the at least one first partial local region of the specimen surface, the back-scattered electrons being generated during the scanning of the at least one first partial local region of the specimen surface.

10. The method according to claim 1 , further comprising the step: modifying the electrical potential distribution of the electrostatic charge in the at least one first partial local region of the specimen surface.

11. The method according to claim 10 , wherein modifying the electrical potential distribution of the electrostatic charge comprises: irradiating the specimen surface with a charged particle beam, and/or applying a plasma discharge to the at least one first partial local region of the specimen surface.

12. The method according to claim 11 , also comprising the step: fixing an irradiation dose of the charged particle beam and/or fixing a time period of the plasma discharge in dependence on the determined electrical potential distribution of the electrostatic charge of the at least one first partial local region.

13. The method of claim 1 in which the specimen comprises at least one of a photomask, a photoresist arranged on a wafer, or a component on a wafer.

14. A device for examining a specimen surface with a charged particle beam of a scanning particle microscope, the specimen surface having an electrical potential distribution of an electrostatic charge, comprising:
means for determining the electrical potential distribution of the electrostatic charge of at least one first partial local region of the specimen surface; and
means for correcting at least one setting of the scanning particle microscope on the basis of a pixel-based determination of the potential distribution of the electrostatic charge for processing at least one second partial local region of the specimen surface with the charged particle beam, the at least one first partial local region of the specimen surface containing the at least one second partial local region of the specimen surface.

15. The device according to claim 14 , the device being designed to perform:
determining the electrical potential distribution of the electrostatic charge of at least one first partial region of the specimen surface;
correcting at least one setting of the scanning particle microscope on the basis of the determined potential distribution of the electrostatic charge for processing at least one second partial local region of the specimen surface with the charged particle beam.

16. The device according to claim 14 , the device comprising at least one spectrometer.

17. The device according to claim 14 , further comprising means for modifying the electrical potential distribution of the electrostatic charge in at least one first partial local region of the specimen surface.

18. The device according to claim 17 , wherein the means for modifying the electrical potential distribution of the electrostatic charge comprises: means for irradiating the specimen surface with a charged particle beam and/or means for applying a plasma discharge to at least the first partial region of the specimen surface.

19. The device of claim 14 in which the specimen comprises at least one of a photomask, a photoresist arranged on a wafer, or a component on a wafer.

Assignees

• Zeiss Carl Smt Gmbh

Inventors

• Budach Michael
• Schnell Michael
• Schindler Bernd
• Boese Markus

Classifications

• H01J2237/2818

  Scanning tunnelling microscopes · CPC title

• H01J37/28 Primary

  with scanning beams {(H01J37/268, H01J37/292, H01J37/2955 take precedence)} · CPC title

• H01J2237/0048

  Charging arrangements · CPC title

• G01Q10/065 Primary

  Feedback mechanisms, i.e. wherein the signal for driving the probe is modified by a signal coming from the probe itself · CPC title

• H01J2237/0041

  Neutralising arrangements · CPC title