Electron Source Architecture for a Scanning Electron Microscopy System

Patent metadata

Field	Value
Publication number	US-2018240640-A1
Application number	US-201815887861-A
Country	US
Kind code	A1
Filing date	Feb 2, 2018
Priority date	Feb 7, 2017
Publication date	Aug 23, 2018
Grant date	—

Abstract

A scanning electron microscopy (SEM) system includes a plurality of electron-optical columns and a plurality of electron beam sources. The electron beam sources include an emitter including one or more emitter tips configured to generate one or more electron beams of a plurality of electron beams. The electron beam sources include a stack of one or more positioners configured to adjust a position of the emitter based on one or more measurements of the electron beam generated by the emitter. The emitter is configured to scan the one or more electron beams across an area surrounding a bore of an electron-optical column of the plurality of electron-optical columns. The electron beam source array includes a carrier plate and a source tower. The source tower is configured to adjust a position of the plurality of electron beam sources relative to a position of the plurality of electron-optical columns.

First claim

What is claimed:

1 . A scanning electron microscopy (SEM) system, comprising:
an electron-optical column array comprising a plurality of electron-optical columns; and an electron beam source array couplable to the electron-optical column array, wherein the electron beam source array comprises:
a plurality of electron beam sources configured to generate a plurality of electron beams, wherein at least some of the electron beam sources comprise: an emitter coupled to an emitter holder, wherein the emitter includes one or more emitter tips configured to generate one or more electron beams of the plurality of electron beams; and a stack of one or more positioners coupled to the emitter holder, wherein the stack of one or more positioners is configured to adjust a position of the emitter based on one or more measurements of the electron beam generated by the emitter, wherein the emitter is configured to scan the one or more electron beams across an area surrounding a bore of a particular electron-optical column of the plurality of electron-optical columns;
a carrier plate coupled to the plurality of electron beam sources; and
a source tower coupled to the carrier plate, wherein the source tower is configured to adjust a position of the plurality of electron beam sources relative to a position of the plurality of electron-optical columns.

2 . The system in claim 1 , wherein the emitter is configured to receive voltage via a voltage terminal coupled to the emitter holder.

3 . The system in claim 2 , wherein the emitter includes two or more emitter tips configured to receive voltage via the voltage terminal coupled to the emitter holder.

4 . The system in claim 3 , wherein at least a second emitter tip of the two or more emitter tips is configured to receive a selected amount of electric current when a first emitter tip of the two or more emitter tips fails.

5 . The system in claim 1 , wherein the at least some of the plurality of electron beam sources comprise:
a thermal bypass, wherein the thermal bypass is positioned between the emitter holder and the stack of one or more positioners, wherein the thermal bypass is positioned between the stack of one or more positioners and the carrier plate, wherein the thermal bypass is configured to transfer heat from the emitter holder to the carrier plate.

6 . The system in claim 1 , wherein the electron beam source array comprises:
a magnetic shield, wherein the magnetic shield surrounds the plurality of electron beam sources, wherein the carrier plate is coupled to the magnetic shield, wherein the source tower is coupled to the magnetic shield.

7 . The system in claim 6 , wherein the source tower is coupled to the magnetic shield via a flexible joint.

8 . The system in claim 1 , wherein the electron-optical element comprises at least one of an electrostatic lens or an electromagnetic lens.

9 . The system in claim 1 , comprising a controller, wherein the controller includes one or more processors configured to receive one or more images from a characterization tool, wherein the controller includes memory configured to store a set of program instructions, wherein the one or more processors are configured to execute the set of program instructions.

10 . The system in claim 9 , wherein the stack of one or more positioners includes one or more actuators, wherein the one or more actuators are configured to adjust the position of the emitter based on the one or more measurements of the electron beam generated by the emitter.

11 . The system in claim 10 , wherein the controller is configured to adjust one or more actuators are via one or more automated adjustment processes.

12 . The system in claim 9 , wherein the source tower includes one or more actuators, wherein the one or more actuators are configured to adjust the position of the plurality of electron beam sources relative to the position of the plurality of electron-optical columns.

13 . The system in claim 12 , wherein the controller is configured to adjust one or more actuators are via one or more automated adjustment processes.

14 . The system in claim 1 , wherein at least one of the electron beam source array or the electron-optical column array includes one or more components fabricated from ultra-high vacuum (UHV) environment-compliant materials.

15 . The system in claim 14 , wherein the electron beam source array and the electron-optical column array share a UHV environment.

16 . The system in claim 1 , further comprising:
one or more kinematic mount assemblies, wherein the electron beam source array is couplable to the electron-optical column array via the one or more kinematic mount assemblies.

17 . The system in claim 16 , wherein the source tower is configured to adjust a position of the plurality of electron beam sources relative to a position of the plurality of electron-optical columns based on feedback from the one or more kinematic mount assemblies.

18 . The system in claim 16 , wherein the one or more kinematic mount assemblies include one or more safety switches.

19 . The system in claim 18 , wherein the source tower is configured to adjust a position of the plurality of electron beam sources relative to a position of the plurality of electron-optical columns based on feedback from the one or more safety switches.

20 . The system in claim 16 , wherein the carrier plate of the electron beam source array is couplable to the electron-optical column array via the one or more kinematic mount assemblies.

21 . The system in claim 1 , comprising a test chamber, wherein at least some of the plurality of electron beams are inspectable via a viewport of the test chamber.

22 . The system in claim 21 , comprising an inspection device, wherein the inspection device is configured to sequentially inspect the at least some of the plurality of electron beams via the viewport in the test chamber.

23 . The system in claim 22 , wherein the inspection device is configured to sequentially inspect the at least some of the plurality of electron beams via the viewport in the test chamber while the electron beam source array is dismounted from the electron-optical column array.

24 . A scanning electron microscopy (SEM) system, comprising:
an electron-optical column array comprising a plurality of electron-optical columns; and an electron beam source array couplable to the electron-optical column array, wherein the electron beam source array comprises a plurality of electron beam sources configured to generate a plurality of electron beams, wherein at least some of the electron beam sources comprise:
an emitter coupled to an emitter holder, wherein the emitter includes one or more emitters tips configured to generate one or more electron beams of the plurality of electron beams;
a stack of one or more actuators coupled to the emitter holder, wherein the stack of one or more actuators is configured to adjust a position of the emitter; and
a thermal bypass, wherein the thermal bypass is positioned between the emitter holder and the stack of one or more positioners, wherein the thermal bypass is positioned between the stack of one or more positioners and the carrier plate, wherein the thermal bypass is configured to transfer heat from the emitter holder to the carrier plate.

25 . A scanning electron microscopy (SEM) system, comprising:
an electron-optical column array comprising a plurality

Assignees

• Kla Tencor Corp

Inventors

• Tahmassebpur Mohammed

Classifications

• H01J37/3002

  Details · CPC title

• H01J2237/0635

  Multiple source, e.g. comb or array · CPC title

• H01J2237/061

  Construction · CPC title

• H01J2237/024

  Moving components not otherwise provided for · CPC title

• H01J37/073

  Electron guns using field emission, photo emission, or secondary emission electron sources · CPC title