Imaging bottom of high aspect ratio holes

Patent metadata

Field	Value
Publication number	US-9632044-B1
Application number	US-201615059063-A
Country	US
Kind code	B1
Filing date	Mar 2, 2016
Priority date	Mar 2, 2016
Publication date	Apr 25, 2017
Grant date	Apr 25, 2017

Abstract

A method that includes performing multiple test iterations to provide multiple test results; and processing the multiple test results to provide estimates of a conductivity of each of the multiple bottoms segments. The multiple test iterations includes repeating, for each bottom segment of the multiple bottom segments, the steps of: (a) illuminating the bottom segment by a charging electron beam; wherein electrons emitted from the bottom segment due to the illuminating are prevented from exiting the hole; (b) irradiating, by a probing electron beam, an area of an upper surface of the dielectric medium; (c) collecting electrons emitted from the area of the upper surface as a result of the irradiation of the area by the probing electron beam to provide collected electrons; and (d) determining an energy of at least one of the collected electrons to provide a test result.

First claim

What is claimed is:

1. A method for evaluating multiple bottom segments of a bottom of a hole formed in a dielectric medium, the method comprising:
performing multiple test iterations to provide multiple test results; and
processing the multiple test results to provide estimates of a conductivity of each of the multiple bottoms segments;
wherein the performing of the multiple test iterations comprises repeating, for each bottom segment of the multiple bottom segments, the steps of:
(a) illuminating the bottom segment by a charging electron beam; wherein electrons emitted from the bottom segment due to the illuminating of the bottom segment are prevented from exiting the hole;
(b) irradiating, by a probing electron beam, an area of an upper surface of the dielectric medium; wherein the area belongs to a region of the upper surface that surrounds the hole;
(c) collecting electrons emitted from the area of the upper surface as a result of the irradiation of the area by the probing electron beam to provide collected electrons; and
(d) determining an energy of at least one of the collected electrons to provide a test result.

2. The method according to claim 1 wherein the probing electron beam is wider than the charging electron beam.

3. The method according to claim 1 comprising a primary electron beam to provide the probing electron beam and focusing the primary electron beam to provide the charging electron beam.

4. The method according to claim 1 wherein the probing electron beam further illuminates the hole.

5. The method according to claim 1 wherein a size of the probing electron beam equals a size of the charging electron beam.

6. The method according to claim 1 wherein a duration of each test iteration does not exceed one microsecond.

7. An inspection system, comprising:
an image acquisition unit that is configured to perform multiple test iterations for testing multiple bottom segments and to provide multiple test results; and
a processor that is configured to process the multiple test results to provide estimates of a conductivity of each bottom segment of the multiple bottom segments;
wherein the image acquisition unit is configured to perform the multiple test iterations by repeating, for each bottom segment of the multiple bottom segments of a bottom of a hole, the steps of:
(a) illuminating the bottom segment by a charging electron beam; wherein electrons emitted from the bottom segment due to the illuminating of the bottom segment are prevented from exiting the hole;
(b) irradiating, by a probing electron beam, an area of an upper surface of a dielectric medium; wherein the area belongs to a region of the upper surface that surrounds the hole;
(c) collecting electrons emitted from the area of the upper surface as a result of the irradiation of the area by the probing electron beam to provide collected electrons; and
(d) determining an energy of at least one of the collected electrons to provide a test result.

8. The inspection system according to claim 7 wherein the probing electron beam is wider than the charging electron beam.

9. The inspection system according to claim 7 wherein the image acquisition unit comprises a focusing lens that is configured to defocus a primary electron beam to provide the probing electron beam and focus the primary electron beam to provide the charging electron beam.

10. The inspection system according to claim 7 wherein the image acquisition unit comprises an electron source for outputting electrons and an supply unit that is configured to (a) supply to the electron source a supply voltage of a first value to provide the probing electron beam, and (b) supply to the electron source a supply voltage of a second value to provide the charging electron beam; and wherein the first value differs from the second value.

11. The inspection system according to claim 7 wherein the image acquisition unit is configured to generate the probing electron beam that further illuminates the hole.

12. The inspection system according to claim 7 wherein a size of the probing electron beam equals a size of the charging electron beam.

13. The inspection system according to claim 7 wherein a duration of each test iteration does not exceed one nanoseconds.

Assignees

• Applied Materials Israel Ltd
• Applied Mat Isreal Ltd

Inventors

• Litman Alon
• Chirko Konstantin

Classifications

• H10P74/203

  Structural properties, e.g. testing or measuring thicknesses, line widths, warpage, bond strengths or physical defects · CPC title

• G01N2223/6116

  semiconductor wafer · CPC title

• G01N23/2251 Primary

  using incident electron beams, e.g. scanning electron microscopy [SEM] · CPC title

• H01L21/67253

  Electricity · mapped topic

• H01L22/12

  Electricity · mapped topic