# US 11,004,651 B2 · Tomography-assisted TEM prep with requested intervention automation workflow

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 11,004,651 B2
- Document ID: US11004651B2
- Status: Granted
- Kind: B2
- Application number: 16/576,565
- Filed: 2019-09-19
- Published: 2020-01-23
- Granted: 2021-05-11
- Earliest claimed: 2017-09-06
- Assignees: FEI Company
- Applicants: FEI Company
- Inventors: Roger Louis Alvis; Trevan R. Landin; Greg Clark
- Web page: https://patentgrep.com/patent/US11004651B2

## CPC

- H01J 37/20: Means for supporting or positioning the object or the material; Means for adjusting diaphragms or lenses associated with the support
- H01J 37/222: {Image processing arrangements associated with the tube}
- H01J 37/28: with scanning beams {(H01J37/268, H01J37/292, H01J37/2955 take precedence)}
- H01J 37/304: Controlling tubes by information coming from the objects {or from the beam}, e.g. correction signals
- H01J 37/3056: {for microworking, e. g. etching of gratings or trimming of electrical components}
- H01J 37/31: for cutting or drilling
- H01J 2237/20285: computer-controlled
- H01J 2237/221: Image processing
- H01J 2237/2802: Transmission microscopes
- H01J 2237/2815: Depth profile
- H01J 2237/30466: Detecting endpoint of process
- H01J 2237/31745: for preparing specimen to be viewed in microscopes or analyzed in microanalysers
- H01J 2237/31747: using STM
- H01J 2237/31749: Focused ion beam
- H01J: ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS (spark-gaps H01T; electric arc lamps H05B31/00; particle accelerators H05H)

## Abstract

Provided is a process for lamella thinning and endpointing that substitutes a series of automated small angle tilts for the motions in the conventional endpointing sequence. STEM images or through-surface BSE scans are acquired at each tilt. The results are analyzed automatically to determine feature depths, and an intervention request is made requesting a user decision based on marked-up images and summary information displayed.

## Claims

### Claim 1

A method comprising:
milling a layer of material from one major lateral side of a workpiece, the workpiece including two major lateral sides;
acquiring an image at each tilt orientation of a small-angle tilt series, the small-angle tilt series including a plurality of tilt orientations;
identifying one or more features in each of the images;
applying metrology to determine respective depths of the one or more features from at least one of the major lateral sides;
requesting an operator intervention in the process by (I) displaying prepared images with measured depths displayed and identified, (II) displaying measured thickness of the workpiece lamella, and (III) presenting a limited choice intervention menu with a first option to mill away a layer on the same major lateral side of the workpiece previously milled and a second option to flip the workpiece and then mill away a layer on the opposing major lateral side of the workpiece;
receiving an operator choice through the limited choice intervention menu; and
based on the operator choice, either flipping the lamella or presenting the previously milled major lateral side of the workpiece lamella toward the ion beam, milling a layer of material from the presented side of the workpiece.

### Claim 2 (depends on 1)

The method of claim 1, wherein the small-angle tilt series includes no more than two projections.

### Claim 3 (depends on 1)

The method of claim 1, wherein the images are STEM projections.

### Claim 4 (depends on 3)

The method of claim 3, wherein identifying one or more features in each of the images includes:
aligning the STEM projections; and
determining tomographic reconstruction of the STEM projections based on the aligned STEM projections.

### Claim 5 (depends on 4)

The method of claim 4, further including preparing a set of tomographic image projections based on the tomographic reconstruction, wherein the prepared images are based on the tomographic image projections.

### Claim 6 (depends on 3)

The method of claim 3, wherein the STEM projections are High Angle Annular Dark Field (HAADF) STEM images.

### Claim 7 (depends on 3)

The method of claim 3, wherein the STEM projections are bright-field (BF) STEM images.

### Claim 8 (depends on 1)

The method of claim 1, wherein identifying one or more features in each of the images includes determining depths of the one or more features from both lateral sides of the workpiece.

### Claim 9 (depends on 1)

The method of claim 1, wherein requesting an operator intervention includes transmitting a notification over a network.

### Claim 10 (depends on 1)

The method of claim 1, further comprising ion beam milling the workpiece from a larger workpiece.

### Claim 11 (depends on 1)

The method of claim 1, further comprising mounting the workpiece to a moveable sample mount.

### Claim 12 (depends on 1)

The method of claim 1, in which preparing the images in (e) further includes identifying pre-determined features by extracting features in the tomographic reconstruction with image processing, and identifying the extracted features based on expected feature dimension data and automated metrology on the extracted features.

### Claim 13 (depends on 1)

The method of claim 1, wherein the images and milling are performed inside a dual-beam charged particle microscope.