# US 10,504,696 B2 · Multi charged particle beam writing apparatus and multi charged particle beam writing method

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- Number: US 10,504,696 B2
- Document ID: US10504696B2
- Status: Granted
- Kind: B2
- Application number: 15/806,564
- Filed: 2017-11-08
- Published: 2018-05-17
- Granted: 2019-12-10
- Earliest claimed: 2016-11-11
- Assignees: NuFlare Technology, Inc.
- Applicants: NuFlare Technology, Inc.
- Inventors: Osamu Iizuka; Yukitaka Shimizu
- Web page: https://patentgrep.com/patent/US10504696B2

## CPC

- H01J 37/3177: {Multi-beam, e.g. fly's eye, comb probe}
- H01J 37/045: {Beam blanking or chopping, i.e. arrangements for momentarily interrupting exposure to the discharge}
- H01J 37/147: Arrangements for directing or deflecting the discharge along a desired path ({H01J37/045 take precedence;} lenses H01J37/10)
- H01J 37/20: Means for supporting or positioning the object or the material; Means for adjusting diaphragms or lenses associated with the support
- H01J 37/244: Detectors; Associated components or circuits therefor
- H01J 37/3023: {Program control}
- H01J 37/304: Controlling tubes by information coming from the objects {or from the beam}, e.g. correction signals
- H01J 2237/0435: Multi-aperture
- H01J 2237/0453: multiple apertures
- H01J 2237/24535: Beam current
- H01J 2237/24564: Measurements of electric or magnetic variables, e.g. voltage, current, frequency
- H01J 2237/24592: Inspection and quality control of devices
- H01J 2237/31774: Multi-beam
- H01J 2237/31798: detecting pattern defects
- H01J: ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS (spark-gaps H01T; electric arc lamps H05B31/00; particle accelerators H05H)

## Abstract

In one embodiment, a multi charged particle beam writing apparatus includes an aperture plate having a plurality of holes to form multiple beams, a blanking aperture array having a plurality of blankers which switch ON-OFF of corresponding respective beams among the multiple beams, a stage on which a writing target substrate is placed, an inspection aperture provided on the stage and that allows one beam among the multiple beams to pass therethrough, a deflector deflecting the multiple beams, a current detector detecting a beam current of each of the multiple beams that has passed through the inspection aperture in a case where the multiple beams are scanned on the inspection aperture, and a control computing machine that generates a beam image based on the detected beam current and detects a defect of the blanking aperture array or the aperture plate based on the beam image.

## Claims

### Claim 1

A multi charged particle beam writing apparatus comprising:
an aperture plate in which a plurality of holes are formed and that forms multiple beams in a case where a charged particle beam passes through the plurality of holes;
a blanking aperture array in which a plurality of blankers are arranged that switch ON-OFF of corresponding respective beams among the multiple beams;
a stage on which a writing target substrate is placed and that is movable in XY directions;
an inspection aperture that is provided at the stage and that allows one beam among the multiple beams to pass therethrough;
a deflector that deflects the multiple beams;
a current detector that detects a beam current of each of the multiple beams that has passed through the inspection aperture in a case where the multiple beams are scanned on the inspection aperture in the XY directions; and
a control computing machine that generates a beam image based on the detected beam current and detects a defect of the blanking aperture array or the aperture plate based on the beam image,
wherein the inspection aperture includes a through hole through which the one beam passes, and
a diameter ϕ1 of the through hole satisfies a following condition:
S<ϕ1<P−S,
wherein S is a beam size of the one beam, and P is a beam pitch of the multiple beams on the writing target substrate.

### Claim 2 (depends on 1)

The apparatus according to claim 1, wherein the blanking aperture array is divided into a plurality of inspection regions, and the inspection aperture is scanned on an inspection region basis.

### Claim 3 (depends on 2)

The apparatus according to claim 2, wherein the control computing machine recognizes beam array regions corresponding to the inspection regions in the beam images.

### Claim 4 (depends on 1)

The apparatus according to claim 1, further comprising: an alignment coil that switches an operation mode to a normal mode in which the substrate is irradiated with beams that have not been deflected by the blankers or to an inversion mode in which the substrate is irradiated with beams that have been deflected by the blankers,
wherein no beam is deflected in a case where a first predetermined voltage is applied to the blankers, and beams are deflected in a case where a second predetermined voltage is applied to the blankers, and
the control computing machine determines a defect type by comparing beam images generated based on beam currents detected in a plurality of respective scans performed on the inspection aperture through switching of the operation mode and the presence or absence of deflection by the blankers.

### Claim 5 (depends on 4)

The apparatus according to claim 4, wherein, in a case where a beam current corresponding to a blanker that is controlled such that the second predetermined voltage is applied is detected in the normal mode, the control computing machine determines that an always ON defect in which the first predetermined voltage is always applied has occurred in this blanker.

### Claim 6 (depends on 4)

The apparatus according to claim 4, wherein, in the normal mode, in a case where no beam current of a beam corresponding to the blanker is detected both when the blanker is controlled such that the first predetermined voltage is applied and when the blanker is controlled such that the second predetermined voltage is applied, the control computing machine determines that an always OFF defect in which the substrate is not irradiated in the normal mode has occurred for this beam.

### Claim 7 (depends on 6)

The apparatus according to claim 6, wherein, in a case where a beam current of the beam for which it has been determined that the always OFF defect has occurred is detected in the inversion mode, the control computing machine determines that a defect in which the second predetermined voltage is always applied has occurred in the blanker corresponding to this beam.

### Claim 8 (depends on 6)

The apparatus according to claim 6, wherein, in a case where no beam current of the beam for which it is determined that the always OFF defect has occurred is detected in the inversion mode, the control computing machine determines that the hole of the aperture plate corresponding to this beam is closed.

### Claim 9 (depends on 1)

The apparatus according to claim 1, wherein the control computing machine determines variations in openings of the holes formed in the aperture plate based on a luminance of each beam in the beam image.

### Claim 10

A multi charged particle beam writing method comprising:
emitting a charged particle beam;
forming multiple beams by allowing the charged particle beam to pass through a plurality of holes of an aperture plate;
performing, using a plurality of blankers provided at a blanking aperture array, blanking deflection on corresponding respective beams;
scanning the multiple beams in XY directions on an inspection aperture that is provided at a stage on which a writing target substrate is placed, the inspection aperture allowing one beam among the multiple beams to pass therethrough;
detecting a beam current of each of the multiple beams that has passed through the inspection aperture;
generating a beam image based on the detected beam current; and
detecting a defect of the blanking aperture array or the aperture plate based on the beam image,
wherein the inspection aperture includes a through hole through which the one beam passes, and
a diameter ϕ1 of the through hole satisfies a following condition:
S<ϕ1<P−S,
wherein S is a beam size of the one beam, and P is a beam pitch of the multiple beams on the writing target substrate.

### Claim 11 (depends on 10)

The method according to claim 10, wherein the blanking aperture array is divided into a plurality of inspection regions, and the inspection aperture is scanned on each of the inspection regions basis.

### Claim 12 (depends on 11)

The method according to claim 11, wherein beam array regions corresponding to the inspection regions are recognized in the beam images.

### Claim 13 (depends on 10)

The method according to claim 10, further comprising switching an operation mode to a normal mode in which the substrate is irradiated with beams that have not been deflected by the blankers or to an inversion mode in which the substrate is irradiated with beams that have been deflected by the blankers,
wherein no beam is deflected in a case where a first predetermined voltage is applied to the blankers, and beams are deflected in a case where a second predetermined voltage is applied to the blankers, and
a defect type is determined by comparing beam images generated based on beam currents detected in a plurality of respective scans performed on the inspection aperture through switching of the operation mode and the presence or absence of deflection by the blankers.

### Claim 14 (depends on 13)

The method according to claim 13, wherein, in a case where a beam current corresponding to a blanker that is controlled such that the second predetermined voltage is applied is detected in the normal mode, it is determined that an always ON defect in which the first predetermined voltage is always applied has occurred in this blanker.

### Claim 15 (depends on 13)

The method according to claim 13, wherein, in the normal mode, in a case where no beam current of a beam corresponding to the blanker is detected both when the blanker is controlled such that the first predetermined voltage is applied and when the blanker is controlled such that the second predetermined voltage is applied, it is determined that an always OFF defect in which the substrate is not irradiated in the normal mode has occurred for this beam.

### Claim 16 (depends on 15)

The method according to claim 15, wherein, in a case where a beam current of the beam for which it has been determined that the always OFF defect has occurred is detected in the inversion mode, it is determined that a defect in which the second predetermined voltage is always applied has occurred in the blanker corresponding to this beam.

### Claim 17 (depends on 15)

The method according to claim 15, wherein, in a case where no beam current of the beam for which it is determined that the always OFF defect has occurred is detected in the inversion mode, it is determined that the hole of the aperture plate corresponding to this beam is closed.

### Claim 18 (depends on 10)

The method according to claim 10, wherein variations in openings of the holes formed in the aperture plate are determined based on a luminance of each beam in the beam image.