公开(公告)号：US20200051779A1

公开(公告)日：2020-02-13

申请号：US16536284

申请日：2019-08-08

Applicant: ASML Netherlands B.V.

Inventor： Weiming REN ,  Xuedong Liu ,  Xuerang Hu ,  Zong-wei Chen

IPC: H01J37/28 ,  H01J37/10 ,  H01J37/147 ,  H01J37/06

Abstract: Systems and methods for observing a sample in a multi-beam apparatus are disclosed. A charged particle optical system may include a deflector configured to form a virtual image of a charged particle source and a transfer lens configured to form a real image of the charged particle source on an image plane. The image plane may be formed at least near a beam separator that is configured to separate primary charged particles generated by the source and secondary charged particles generated by interaction of the primary charged particles with a sample. The image plane may be formed at a deflection plane of the beam separator. The multi-beam apparatus may include a charged-particle dispersion compensator to compensate dispersion of the beam separator. The image plane may be formed closer to the transfer lens than the beam separator, between the transfer lens and the charged-particle dispersion compensator.

公开(公告)号：US10395886B2

公开(公告)日：2019-08-27

申请号：US15216258

申请日：2016-07-21

Applicant: ASML Netherlands B.V.

Inventor： Weiming Ren ,  Xuedong Liu ,  Xuerang Hu ,  Zhongwei Chen

IPC: H01J37/14 ,  H01J37/147 ,  H01J37/06 ,  H01J37/10 ,  H01J37/28

Abstract: A multi-beam apparatus for observing a sample with high resolution and high throughput is proposed. In the apparatus, a source-conversion unit forms plural and parallel images of one single electron source by deflecting plural beamlets of a parallel primary-electron beam therefrom, and one objective lens focuses the plural deflected beamlets onto a sample surface and forms plural probe spots thereon. A movable condenser lens is used to collimate the primary-electron beam and vary the currents of the plural probe spots, a pre-beamlet-forming means weakens the Coulomb effect of the primary-electron beam, and the source-conversion unit minimizes the sizes of the plural probe spots by minimizing and compensating the off-axis aberrations of the objective lens and condenser lens.