US 9,177,758 B2 · Charged particle beam apparatus

Abstract

The present invention provides a dual-beam apparatus which employs the dark-field e-beam inspection method to inspect small particles on a surface of a sample such as wafer and mask with high throughput. The dual beam apparatus comprises two single-beam dark-field units placed in a same vacuum chamber and in two different orientations. The two single-beam dark-field units can perform the particle inspection separately or almost simultaneously by means of the alternately-scanning way. The invention also proposes a triple-beam apparatus for both inspecting and reviewing particles on a sample surface within the same vacuum chamber. The triple-beam apparatus comprises one foregoing dual-beam apparatus performing the particle inspection and one high-resolution SEM performing the particle review.

Claims23

Dependent claims

A method for inspecting a patterned surface of a sample, comprising:

providing two single-beam units and each of which comprises:
a primary electron beam (PE beam), which obliquely illuminates and scans said patterned surface and thereby generating backscattered electrons and secondary electrons therefrom;
a detector with a through hole for said PE beam passing through, which detects said backscattered electrons traveling towards an incidence side of said PE beam;
and
an electrode close to said patterned surface, which attracts said secondary electrons from hitting said detector so that said detector provides a dark-field BSE image of said patterned surface;
orientating said PE beams of said two single-beam units in two different directions;
and
using said two single-beam units to generate dark-field BSE images of said patterned surface.

5 more elements

A multi-beam apparatus for observing a patterned surface of a sample, comprising:

a sample stage supporting said sample, wherein said patterned surface is placed upwards and coincides with an observing plane;
a first single-beam unit above said observing plane to inspect said patterned surface;
and
a second single-beam unit above said observing plane to inspect said patterned surface,
wherein each of said first and second single-beam units comprises:
an electron source emitting inspection primary electrons along an optical axis of said single-beam unit and said inspection primary electrons form an inspection primary electron beam (PE beam) thereof;
a gun aperture plate below said electron source and having at least one upper opening, wherein one of the upper openings of said gun aperture plate is aligned with said optical axis and limits a current of said inspection PE beam to a first current value;
a condenser lens below said gun aperture plate and aligned with said optical axis;
a beam-limit aperture plate below said condenser lens and having at least one lower opening, wherein one of the lower openings of said beam-limit aperture plate is aligned with said optical axis and limits said current of said inspection PE beam to a second current value;
a magnetic objective lens below said beam-limit aperture plate and aligned with said optical axis;
a scanning deflection device inside a bore of said magnetic objective lens;
an electron detector below said magnetic objective lens and having a through hole, wherein said through hole is aligned with said optical axis so that said inspection PE beam can pass through;
and
an attraction electrode beside said electron detector and above said observing plane,
wherein an incidence angle formed between said optical axis and a normal of said observing plane is larger than 0°,
wherein said condenser lens and said magnetic objective lens together focus said inspection PE beam onto said patterned surface,
wherein an electron detection area of said electron detector aslant faces said observing plane so as to be able to collect backscattered electrons which are generated from said patterned surface by said inspection PE beam and travel towards an incidence side thereof (called as Dark-field BSEs),
wherein said attraction electrode attracts secondary electrons generated from said patterned surface by said inspection PE beam (called as SEs) to prevent said SEs from hitting said electron detection area of said electron detector,
wherein said scanning deflection device deflects said inspection PE beam so as to scan said patterned surface, thereby obtaining a dark-field BSE image thereof by said electron detector;
wherein said optical axes of said first and second single-beam units are orientated in two different directions.

17 more elements

Dependencies are inferred from the claim text.

Charged particle beam apparatus

Life of this patent

Charged particle beam apparatus

Life of this patent

Abstract

Claims23