Mass distribution spectrometry method and mass distribution spectrometer

Patent metadata

Field	Value
Publication number	US-9312116-B2
Application number	US-201214343245-A
Country	US
Kind code	B2
Filing date	Oct 25, 2012
Priority date	Nov 17, 2011
Publication date	Apr 12, 2016
Grant date	Apr 12, 2016

Abstract

The present invention provides a mass distribution spectrometry which reduces an influence of the dispersion in the times at which ionizing beams irradiate a sample, on a mass spectrometry result, and can measure the mass distribution with high reliability. The mass distribution spectrometry is a mass spectrometry which includes irradiating the sample with a primary ion beam and detecting generated secondary ions, wherein this primary ion beam has a spread toward a direction perpendicular to a travelling direction, has a path length of each primary ion contained in the primary ion beam between a primary ion source and a surface of the sample adjusted by deflecting a trajectory, and is obliquely incident on the surface of the sample.

First claim

The invention claimed is:

1. A mass distribution spectrometry method including irradiating a sample with a primary ion beam and detecting a generated secondary ion,
wherein the primary ion beam having a spread toward a direction perpendicular to a travelling direction is obliquely incident on a surface of the sample after a path length of each primary ion contained in the primary ion beam is adjusted by deflecting a trajectory between a primary ion source and the surface of the sample,
wherein the mass distribution spectrometry method is a projection type mass distribution spectrometry method, and
wherein path lengths of primary ions incident on arbitrary two points on the surface of the sample on which the primary ions are incident are adjusted so that:
a difference of the path lengths of the primary ions incident on the two points becomes smaller than d*cos θ, when d is defined as a distance in an incident direction of the ion beam between the arbitrary two points which have been projected on a horizontal plane on the surface of the sample, and θ is defined as an incident angle of an ion which is incident on either one of the points out of the two points.

2. The mass distribution spectrometry method according to claim 1 , wherein the secondary ion is detected with a time-of-flight ion detection method.

3. The mass distribution spectrometry method according to claim 1 , further comprising simultaneously detecting two-dimensionally positional information of secondary ions at a time when the secondary ions are generated.

4. The mass distribution spectrometry method according to claim 1 , wherein the trajectory is deflected by an electrostatic force or a magnetic force.

5. The mass distribution spectrometry method according to claim 1 , wherein the trajectory is deflected by an electrostatic force generated by a pair of deflection electrodes positioned so as to oppose each other with the trajectory sandwiched therebetween.

6. The mass distribution spectrometry method according to claim 1 , wherein the arbitrary two points are two points of which the d becomes a maximal value of the distance in the incident direction of the ion beam between two points which the ions reach.

7. The mass distribution spectrometry method according to claim 1 , wherein the generated secondary ion is projected to a two-dimensional ion detector.

8. The mass distribution spectrometry method according to claim 7 , wherein the two-dimensional ion detector comprises a microchannel plate (MCP), a fluorescent plate, or a two-dimensional photodetector.

9. The mass distribution spectrometry method according to claim 1 , wherein the path length is adjusted so that amounts of time for the primary ions to reach the surface of the sample become equal.

10. A mass distribution spectrometer including a primary ion irradiation unit and a detecting device for a secondary ion which has been generated by irradiation for a sample with a primary ion,
wherein the primary ion irradiation unit is configured to:
form a primary ion beam which has a spread toward a direction perpendicular to a travelling direction;
adjust a path length of each primary ion contained in the primary ion beam between a primary ion source and a surface of the sample, by deflecting a trajectory of the primary ion, so that a difference of path lengths of primary ions incident on two arbitrary two points on the surface of the sample becomes smaller than d*cos θ, when d is defined as a distance in an incident direction of the ion beam between the arbitrary two points which have been projected on a horizontal plane on the surface of the sample, and θ is defined as an incident angle of an ion which is incident on either one of the points out of the two points; and
irradiate the surface of the sample obliquely with the primary ion having the spread toward the direction perpendicular to the travelling direction, after the path length has been adjusted, and
wherein the mass distribution spectrometer is configured to perform projection type mass distribution spectrometry.

11. The mass distribution spectrometer according to claim 10 , which comprises a two-dimensional ion detector for projecting the generated secondary ion.

12. The mass distribution spectrometer according to claim 11 , wherein the two-dimensional ion detector comprises a microchannel plate (MCP), a fluorescent plate, or a two-dimensional photodetector.

13. A mass distribution spectrometer including a primary ion irradiation unit for irradiating a surface of a sample obliquely with a primary ion, and a detecting device for detecting a secondary ion which has been generated from the sample,
wherein the primary ion irradiation unit has a deflection unit for deflecting paths of emitted primary ions toward an incident direction so that the emitted primary ions maintain a state having a spread toward a direction perpendicular to a travelling direction, so that amounts of time for the emitted primary ions to reach the surface of the sample become equal, and so that trajectories of the emitted primary ions are adjusted such that path lengths of all of the emitted primary ions become equal, and
wherein the mass distribution spectrometer is configured to perform projection type mass distribution spectrometry.

14. The mass distribution spectrometer according to claim 13 , further comprising:
an acquiring unit for acquiring mass distribution on the surface of the sample from signals of the secondary ions, which have been detected by the detecting device; and
a displaying unit for outputting the acquired mass distribution.

15. The mass distribution spectrometer according to claim 13 , which comprises a two-dimensional ion detector for projecting the generated secondary ion.

16. The mass distribution spectrometer according to claim 15 , wherein the two-dimensional ion detector comprises a microchannel plate (MCP), a fluorescent plate, or a two-dimensional photodetector.

17. A mass distribution spectrometry method including irradiating a sample with a primary ion beam and detecting a generated secondary ion,
wherein the primary ion beam having a spread toward a direction perpendicular to a travelling direction is obliquely incident on a surface of the sample after a path length of each primary ion contained in the primary ion beam is adjusted by deflecting a trajectory between a primary ion source and the surface of the sample,
wherein the mass distribution spectrometry method is a projection type mass distribution spectrometry method, and
wherein the primary ion beam is incident on the surface of the sample, after the path length is adjusted between the primary ion source and the surface of the sample, so that amounts of time for primary ions to reach the surface of the sample become equal and path lengths of all of the primary ions become equal.

Assignees

• Canon Kk

Inventors

• Kyogaku Masafumi
• Iwasaki Kota

Classifications

• H01J49/0004

  Imaging particle spectrometry · CPC title

• H01J49/06

  Electron- or ion-optical arrangements · CPC title

• H01J49/0031

  Step by step routines describing the use of the apparatus (H01J49/0081 takes precedence) · CPC title

• H01J49/40

  Time-of-flight spectrometers (H01J49/36 takes precedence) · CPC title

• H01J49/142

  using a solid target which is not previously vapourised · CPC title