Time-resolved charged particle microscopy

Patent metadata

Field	Value
Publication number	US-10032599-B2
Application number	US-201615364163-A
Country	US
Kind code	B2
Filing date	Nov 29, 2016
Priority date	Nov 28, 2016
Publication date	Jul 24, 2018
Grant date	Jul 24, 2018

Abstract

A method of investigating a specimen using charged particle microscopy, comprising the following steps:
Using a primary source to produce a pulsed beam of charged particles that propagate along a beam path; Providing a specimen at an irradiation position in said beam path; Using a secondary source to produce repetitive excitations of the specimen; Using a detector to register charged particles in said beam that traverse the specimen after each said excitation,

wherein:
Said primary source is configured to produce a train of multiple pulses per excitation by said secondary source; Said detector is configured to comprise an integrated array of pixels, each with an individual readout circuit, to register a time-of-arrival of individual particles in said train.

First claim

The invention claimed is:

1. A method of investigating a specimen using charged particle microscopy, comprising:
providing, by a primary source, a pulsed beam of charged particles to the specimen;
while providing the pulsed beam of charged particles, exciting, by a secondary source, the specimen coincidentally with the pulsed beam of charged particles;
detecting, by a detector, charged particles that traverse the specimen after each said excitation; and
determining, by the detector, a time-of-arrival of individual charged particles that traverse the specimen, wherein the detector includes an integrated array of pixels, each with an individual readout circuit.

2. A method according to claim 1 , wherein the pulsed beam of charged particles includes a plurality of pulses, and wherein the plurality of pulses are incident on the specimen while the specimen is being excited.

3. A method according to claim 2 , wherein a phase of said pulse train is adjusted between two successive excitations of said specimen.

4. A method according to claim 1 , wherein said primary source comprises an oscillatory electromagnetic beam deflector.

5. A method according to claim 4 , wherein said deflector comprises a TM 110 RF cavity beam chopper.

6. A method according to claim 4 , wherein:
said primary source comprises a series arrangement of an RF cavity beam chopper and an oscillatory electromagnetic beam deflector; and
an operating frequency of said oscillatory electromagnetic beam deflector is matched to a frequency of said excitations.

7. A method according to claim 1 , wherein said secondary source is a laser.

8. A method according to claim 1 , wherein a phase of said pulsed beam of charged particles is adjusted between two successive excitations of said specimen.

9. A method according to claim 1 , wherein, for the primary source, values of a pulse duration d p and pulse repetition rate r p are selected from the group consisting of:
d p <1 ns and r p >50 MHz;
d p <100 ps and r p >300 MHz; and
d p ≤1 ps and r p ≥1 GHz.

10. A charged particle microscope comprising:
a primary source, for producing a pulsed beam of charged particles that propagate along a beam path;
a specimen holder, for holding a specimen at an irradiation position in said beam path;
a secondary source, for producing repetitive excitations of the specimen;
a detector, for registering charged particles in said beam that traverse the specimen after each said excitation; and
an electronic controller, for administering operational characteristics of the microscope,
wherein:
said controller is configured to operate said primary source so as to produce a train of multiple pulses per excitation by said secondary source; and
said detector is configured to comprise an integrated array of pixels, each with an individual readout circuit, to register a time-of-arrival at the detector of individual particles in said train.

11. The charged particle microscope of claim 10 , wherein the primary source comprises:
a source of a continuous beam of charged particles along the beam path; and
one or more deflectors to produce the pulsed beam of charged particles.

12. The charged particle microscope of claim 10 , wherein the primary source comprises a series arrangement of an RF cavity beam chopper and an oscillatory electromagnetic beam deflector operating at a frequency matched to a frequency of said excitations.

13. A method of investigating a specimen, comprising:
repetitively exciting the specimen using a secondary source;
irradiating the specimen with multiple charged particle pulses after an excitation;
registering, at a detector including an array of pixels, a time of arrival of individual charged particles that pass through the specimen after the excitation; and
reading out the times of arrival of individual charged particles using individual pixels readout circuits.

14. The method of claim 13 , wherein repetitively exciting the specimen using a secondary source comprises repetitively exciting the specimen using a laser.

15. The method of claim 13 , wherein irradiating the specimen with multiple charged particle comprises:
producing from a source a continuous beam of charged particles; and
deflecting the continuous beam of charged particles to form the pulsed beam of charged particles that irradiate the specimen.

16. The method of claim 13 , wherein registering, at a detector including an array of pixels, a time of arrival of individual charged particles comprises registering particles with a hybrid detector having a semiconductor sensor layer bonded to a processing electronics layer, and further having time-over-threshold and/or time-of arrival functionalities.

17. The method of claim 13 , wherein irradiating the specimen with multiple charged particle pulses comprises producing a train of multiple pulses by passing a continuous beam of charged particles through a series arrangement of an RF cavity beam chopper and an oscillatory electromagnetic beam deflector.

18. The method of claim 17 , wherein producing a train of multiple pulses by passing a continuous beam of charged particles through a series arrangement of an RF cavity beam chopper and an oscillatory electromagnetic beam deflector comprises producing a train of multiple pulses by passing a continuous beam of charged particles through a series arrangement of an RF cavity beam chopper and an oscillatory electromagnetic beam deflector operating at an operating frequency matched to a frequency of the repetitive excitations of the specimen using the secondary source.

Assignees

• Fei Co
• FEI Cmnpany

Inventors

• Kieft Erik René

Classifications

• H01J2237/2802

  Transmission microscopes · CPC title

• H01J37/244

  Detectors; Associated components or circuits therefor · CPC title

• G01N23/2202

  Preparing specimens therefor · CPC title

• H01J2237/0432

  High speed and short duration · CPC title

• H01J37/045 Primary

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