CHARGED PARTICLE BEAM SYSTEM AND METHOD OF OPERATING THEREOF

• US 20140367586A1
• Filed: 06/18/2013
• Published: 12/18/2014
• Est. Priority Date: 06/17/2013
• Status: Active Grant

• Current Assignee: ICT Integrated Circuit Testing Gesellschaft Fur Halbleiterpruftechnik mbH
• Original Assignee: ICT Integrated Circuit Testing Gesellschaft Fur Halbleiterpruftechnik mbH
• Inventors: FROSIEN, Jrgen, COOK, Benjamin John
• Granted Patent: US 9,305,740 B2
• Time in Patent Office: Days
• US Class Current: 250/397
• CPC Class Codes: H01J 2237/1534 Aberrations
• CPC Class Codes: H01J 2237/281 Bottom of trenches or holes
• CPC Class Codes: H01J 2237/2815 Depth profile
• CPC Class Codes: H01J 37/045 Beam blanking or chopping, i.e. arrangements for momentarily interrupting exposure to the discharge
• CPC Class Codes: H01J 37/1478 Beam tilting means, i.e. for stereoscopy or for beam channelling
• CPC Class Codes: H01J 37/153 Electron-optical or ion-optical arrangements for the correction of image defects, e.g. stigmators
• CPC Class Codes: H01J 37/263 Contrast, resolution or power of penetration

Abstract

A charged particle beam device is described. In one aspect, the charged particle beam device includes a charged particle beam source, and a switchable multi-aperture for generating two or more beam bundles from a charged particle beam which includes: two or more aperture openings, wherein each of the two or more aperture openings is provided for generating a corresponding beam bundle of the two or more beam bundles; a beam blanker arrangement configured for individually blanking the two or more beam bundles; and a stopping aperture for blocking beam bundles. The device further includes a control unit configured to control the individual blanking of the two or more beam bundles for switching of the switchable multi-aperture and an objective lens configured for focusing the two or more beam bundles on a specimen or wafer.

Claims

1. A charged particle beam device, comprising:

a charged particle beam source for emitting a charged particle beam;

a switchable multi-aperture for generating two or more beam bundles from the charged particle beam, wherein the switchable multi-aperture comprises;

two or more aperture openings, wherein each of the two or more aperture openings is provided for generating a corresponding beam bundle of the two or more beam bundles;

a beam blanker arrangement configured for individually blanking the two or more beam bundles; and

a stopping aperture for blocking beam bundles, which are blanked off by the beam blanker arrangement;

a control unit electrically connected to the beam blanker arrangement and configured to control the individual blanking of the two or more beam bundles for switching of the switchable multi-aperture; and

an objective lens configured for focusing the two or more beam bundles on a specimen or wafer, wherein the two or more beam bundles are tilted with respect to the specimen or wafer depending on the position of each of the two or more beam bundles relative to an optical axis defined by the objective lens, and wherein the objective lens is configured for focusing the charged particle beam source, a virtual source provided by the charged particle beam source or a crossover.

2. The device according to claim 1, wherein the beam blanker arrangement is wherein the beam blanker arrangement is provided in the same module as the two or more aperture openings or wherein the plane of the blanker arrangement perpendicular to the optical axis has a distance from the plane of the two or more aperture openings, which is 10 mm or less.

3. The device according to claim 1, wherein the beam blanker arrangement is wherein the beam blanker arrangement is provided in the same module as the two or more aperture openings and wherein the plane of the blanker arrangement perpendicular to the optical axis has a distance from the plane of the two or more aperture openings, which is 10 mm or less.

4. The device according to claim 2, wherein the plane of the blanker arrangement perpendicular to the optical axis has a distance from the plane of the two or more aperture openings, which is 3 mm or less.

5. The device according to claim 1, wherein the beam blanker arrangement comprises two or more multi-pole elements.

6. The device according to claim 5, wherein the two or more multi-pole elements are selected from the group consisting of:

a quadrupole, an hexapole, an octupole, or an n-pole with n>

8.

7. The device according to claim 5, wherein the multi-pole element is configured to allow for at least one beam bundle adjustment for each of the two or more beam bundles individually, wherein the beam bundle adjustment is selected from the group consisting of:

beam bundle position, beam bundle astigmation correction, beam bundle focusing, and beam bundle focus adjustment.

8. The device according to claim 1, wherein the two or more beam bundles are focused within the same area of the specimen or wafer

9. The device according to claim 8, wherein the two or more beam bundles are focused onto the same location within the focal plane wherein the same location within the focal plane is a probe generated on a specimen, which is an image of the source, the virtual source or the crossover.

10. The device according to claim 1, wherein at least one aperture opening of the two or more aperture openings are configured to change its position in a projection on a plane perpendicular to the optical axis.

11. The device according to claim 1, further comprising:

a separating unit configured for separating the two or more beam bundles, which are focused on the specimen or wafer, from signal electrons generated on impingement of the two or more beam bundles on the specimen or wafer.

12. The device according to claim 1, further comprising:

a detector arrangement having two or more detection segments or detection elements.

13. The device according to claim 12, wherein the two or more detection segments are provided by a segmented scintillator, by a fiber optics receiving photons from a photon generating element, or by a scintillator and a fiber optics, which guide the signal to separate detection elements of the two or more detection elements.

14. The device according to claim 12, wherein the detector arrangement having at least two detection elements with active detection areas, wherein the active detection areas are separated by a gap;

a particle optics configured for separating the signal electrons into a first portion of the signal electrons and into at least one second portion of the signal electrons, and configured for focusing the first portion of the signal electrons and the at least one second portion of the signal electrons, wherein the particle optics comprises;

an aperture plate; and

at least a first aperture opening in the aperture plate, and at least one second aperture opening in the aperture plate,

wherein the aperture plate is configured to be biased to one potential surrounding the first aperture opening and the at least one second aperture opening.

15. The device according to claim 14, wherein the at least one second aperture opening is at least one second radially outer aperture opening.

16. The device according to claim 15, wherein the at least one second aperture opening is at least four outer aperture openings.

17. A method of generating a 3D image of a specimen or wafer, comprising:

imaging the specimen or wafer with a first group of beam bundles, wherein the first group of beam bundles includes one or more beam bundles;

switching from the first group of beam bundles to a second group of beam bundles with a switchable multi-aperture, wherein the second group of beam bundles can include one or more beam bundles, and wherein at least one beam bundle differs in the second group of beam bundles as compared to the first group of beam bundles; and

imaging the specimen or wafer with the second group of beam bundles, wherein the one or more beam bundles are tilted with respect to the specimen or wafer depending on the position of each of the one or more beam bundles relative to an optical axis defined by an objective lens.

18. The method according to claim 17, wherein the switchable multi-aperture comprises:

two or more aperture openings, wherein each of the two or more aperture openings is provided for generating a corresponding beam bundle;

a beam blanker arrangement configured for individually blanking a beam bundle; and

a stopping aperture for blocking beam bundles, which are blanked off by the beam blanker arrangement; and

wherein the switching comprises;

control of the individual blanking of beam bundles.

19. The method according to claim 17, wherein a high current imaging mode is provided by switching on at least 80% of the beam bundles, wherein in an arbitrary sequential order a hole imaging mode is provided by switching on only a center beam bundle travelling, wherein the center beam bundle is the beam bundle with the smallest distance to the optical axis, and wherein in an arbitrary sequential order a side-enhanced imaging mode is provided by switching on one or more beam bundles from the enhanced side and switching off one or more beam bundles from a second side opposite to the enhanced side.