# US 11,443,916 B2 · Thin pellicle material for protection of solid-state electron detectors

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- Number: US 11,443,916 B2
- Document ID: US11443916B2
- Status: Granted
- Kind: B2
- Application number: 17/197,124
- Filed: 2021-03-10
- Published: 2021-10-21
- Granted: 2022-09-13
- Earliest claimed: 2020-04-15
- Assignees: KLA Corporation
- Applicants: KLA Corporation
- Inventors: William G. Schultz
- Web page: https://patentgrep.com/patent/US11443916B2

## CPC

- H01J 37/244: Detectors; Associated components or circuits therefor
- H01J 37/3007: {Electron or ion-optical systems}
- H01J 2237/0203: Protection arrangements
- H01J 2237/24475: Scattered electron detectors
- H01J: ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS (spark-gaps H01T; electric arc lamps H05B31/00; particle accelerators H05H)

## Abstract

An electron beam system and method are provided. The system includes a detector having a detector face configured to detect back-scattered electrons reflected off of a sample. The system further includes an annular cap disposed on the detector face, and a protective pellicle disposed on the annular cap, covering the detector face. The protective pellicle is transparent to back-scattered electrons and provides a physical barrier to particles directed at the detector face.

## Claims

### Claim 1

An electron beam system comprising:
a detector comprising a detector face configured to detect back-scattered electrons reflected off of a sample;
an annular cap disposed on the detector face; and
a protective pellicle disposed on the annular cap, covering the detector face;
wherein the protective pellicle is transparent to back-scattered electrons and provides a physical barrier to particles directed at the detector face.

### Claim 2 (depends on 1)

The electron beam system of claim 1, wherein the protective pellicle is monoatomic.

### Claim 3 (depends on 1)

The electron beam system of claim 1, wherein the protective pellicle is graphene or a graphene analog.

### Claim 4 (depends on 1)

The electron beam system of claim 1, wherein the protective pellicle is an electrical conductor, configured to drain charge from particles directed at the detector face intercepted by the protective pellicle.

### Claim 5 (depends on 1)

The electron beam system of claim 1, wherein the protective pellicle is a thermal conductor, configured to dissipate heat from particles directed at the detector face intercepted by the protective pellicle.

### Claim 6 (depends on 1)

The electron beam system of claim 1, wherein the detector face is annular, such that an electron beam passes through the center of the detector face toward the sample.

### Claim 7 (depends on 6)

The electron beam system of claim 6, wherein the protective pellicle includes an aperture, such that the electron beam passes through the aperture toward the sample.

### Claim 8 (depends on 1)

The electron beam system of claim 1, further comprising:
an electron beam source configured to direct an electron beam toward the sample.

### Claim 9

A method comprising:
generating an electron beam using an electron beam source;
directing the electron beam toward a surface of a sample;
generating back-scattered electrons and particles at the surface of the sample based on interaction between the electron beam and the sample, the back-scattered electrons and particles being emitted away from the surface of the sample;
detecting the back-scattered electrons on a detector face of a detector;
preventing the particles from reaching the detector face by a protective pellicle, the protective pellicle being disposed on an annular cap on the detector face, transparent to the back-scattered electrons, and providing a physical barrier to the particles directed at the detector face.

### Claim 10 (depends on 9)

The method of claim 9, wherein the protective pellicle is monoatomic.

### Claim 11 (depends on 9)

The method of claim 9, wherein the protective pellicle is graphene or a graphene analog.

### Claim 12 (depends on 9)

The method of claim 9, wherein the protective pellicle is an electrical conductor, and the method further comprises:
draining charge from the particles directed at the detector face intercepted by the protective pellicle.

### Claim 13 (depends on 9)

The method of claim 9, wherein the protective pellicle is a thermal conductor, and the method further comprises:
dissipating heat from the particles directed at the detector face intercepted by the protective pellicle.

### Claim 14 (depends on 9)

The method of claim 9, wherein detector face is annular, and directing the electron beam toward a surface of a sample comprises:
directing the electron beam toward the surface of the sample through the detector face.

### Claim 15 (depends on 14)

The method of claim 14, wherein the protective pellicle includes an aperture, and directing the electron beam toward a surface of a sample further comprises:
directing the electron beam toward the surface of the sample through the aperture of the protective pellicle.