# US 10,026,589 B1 · Alignment and registration targets for charged particle beam substrate patterning and inspection

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- Number: US 10,026,589 B1
- Document ID: US10026589B1
- Status: Granted
- Kind: B1
- Application number: 15/454,872
- Filed: 2017-03-09
- Granted: 2018-07-17
- Earliest claimed: 2013-11-27
- Applicants: Multibeam Corporation
- Inventors: Kevin M. Monahan; Michael C. Smayling; Theodore A. Prescop; David K. Lam
- Web page: https://patentgrep.com/patent/US10026589B1

## CPC

- H01J 37/3045: {Object or beam position registration}
- H01J 37/20: Means for supporting or positioning the object or the material; Means for adjusting diaphragms or lenses associated with the support
- H01J 37/265: {Controlling the tube; circuit arrangements adapted to a particular application not otherwise provided, e.g. bright-field-dark-field illumination}
- H01J 37/3005: {Observing the objects or the point of impact on the object}
- H01J 37/3177: {Multi-beam, e.g. fly's eye, comb probe}
- H01J 2237/208: Elements or methods for movement independent of sample stage for influencing or moving or contacting or transferring the sample or parts thereof, e.g. prober needles or transfer needles in FIB/SEM systems
- H01J 2237/2826: Calibration
- H01J 2237/30444: Calibration grids
- H01J 2237/30472: Controlling the beam
- H01J 2237/31764: Dividing into sub-patterns
- H01J: ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS (spark-gaps H01T; electric arc lamps H05B31/00; particle accelerators H05H)

## Abstract

The present application discloses methods, systems and devices for using charged particle beam tools to pattern and inspect a substrate. The inventors have discovered that it is highly advantageous to use patterns generated using the Hadamard transform as alignment and registration marks (Hadamard targets) for multiple-column charged particle beam substrate processing and inspection tools. Hadamard targets can be written to a substrate using charged particle beams performing, for example, resist-based lithography or resist-less direct processing. High-order Hadamard targets can also be patterned and imaged to obtain superior column performance metrics for applications such as super-rapid beam calibration DOE, column matching, and column performance tracking. Hadamard target blocks can be written highly locally to electrically functional pattern portions, or integrated into said pattern portions, thereby enabling re-registration local and contemporaneous to writing and improving beam targeting accuracy following re-registration. Superior alignment and registration, and column parameter optimization, allow significant yield gains.

## Claims

### Claim 1

A method of substrate patterning and/or inspection using one or more charged particle beam columns, comprising the actions of:
a) writing multiple block-based Hadamard targets onto the substrate using one or more first charged particle beams;
b) imaging said Hadamard targets using one or more second charged particle beams;
c) calculating offsets for respective ones of said second beams in at least partial dependence on said imaging; and
d) writing and/or imaging multiple features using said second beams, said features being targeted in at least partial dependence on said offsets,
wherein individual ones of said beams are projected by individual ones of the columns, and different ones of the columns have different writing areas.

### Claim 2 (depends on 1)

The method of claim 1, wherein, in step a), said first beams write at least one Hadamard target in the writing area of each column projecting said second beams.

### Claim 3 (depends on 1)

The method of claim 1, wherein said first beams are produced by the same charged particle beam tool, and/or by the same array of columns, and/or by the same columns, as said second beams.

### Claim 4 (depends on 1)

The method of claim 1, wherein the substrate is moved from one stage to a different stage between step a) and step b).

### Claim 5 (depends on 1)

The method of claim 1, wherein different ones of said beams perform said writing and/or said imaging differently and simultaneously.

### Claim 6 (depends on 1)

The method of claim 1, wherein said offsets are calculated also in at least partial dependence on the design layout database of the substrate and the position of the stage on which the substrate is mounted.

### Claim 7 (depends on 1)

The method of claim 1, wherein said features comprise line-cuts and holes.

### Claim 8 (depends on 1)

The method of claim 1, wherein said imaging said Hadamard targets comprises initial-imaging expected locations of center and/or most-symmetric blocks of said Hadamard targets at least sufficiently to determine which portions of said Hadamard targets were imaged, calculating actual locations of said blocks in at least partial dependence on said initial-imaging, and refined-imaging at said actual locations.

### Claim 9 (depends on 1)

The method of claim 1, wherein at least some of said Hadamard targets are high-order Hadamard targets.

### Claim 10 (depends on 1)

The method of claim 1, wherein said first beams write features to the substrate in addition to said Hadamard targets.

### Claim 11 (depends on 1)

The method of claim 1, wherein two or more of the blocks in at least one of said Hadamard targets are transposed within said Hadamard target.

### Claim 12 (depends on 11)

The method of claim 11, wherein said Hadamard targets comprising transposed blocks are used to identify, track, and/or authenticate the individual substrate-derived product unit to which they are written.

### Claim 13

A method of substrate patterning and/or inspection using one or more charged particle beam columns, comprising:
a) writing multiple high-order block-based Hadamard targets to the substrate using one or more first charged particle beams;
b) imaging multiple features in said high-order Hadamard targets using one or more second charged particle beams;
c) measuring beam performance in at least partial dependence on said imaging, and determining which of said features were correctly imaged in step b); and
d) until one or more features of a threshold size are correctly imaged, modifying beam parameters of said second beams in at least partial dependence on said measuring to stochastically improve beam performance, and repeating steps b) and c), targeting one or more features in said repeated step b) that are smaller than those previously determined as correctly imaged;
wherein individual ones of said beams are projected by individual ones of the columns, and different ones of the columns have different writing areas.

### Claim 14 (depends on 13)

The method of claim 13, wherein said beam parameters are selected from: beam energy, beam focus, exposure time, beam current, beam landing energy, beam size, beam initial position, and beam scan rate.

### Claim 15 (depends on 13)

The method of claim 13, wherein said measuring uses criteria selected from: beam resolution, contrast, signal-to-noise ratio, edge-sharpness, and deflection accuracy.

### Claim 16 (depends on 13)

The method of claim 13, wherein the substrate is not removed from the stage between step b) and step e).

### Claim 17 (depends on 13)

The method of claim 13, wherein said targets are generated using the discrete Hadamard and/or Walsh transform basis kernels using N≥10.

### Claim 18 (depends on 13)

The method of claim 13, wherein said targets are configured such that, using initial and/or non-optimized beam parameters, at least some features of said targets can be correctly imaged and at least some target features cannot be correctly imaged.

### Claim 19 (depends on 13)

The method of claim 13, wherein steps b) through d) are repeated multiple times, on one or more different substrates, using multiple different high-order Hadamard targets comprising either or both of (1) a high-order Hadamard target with transposed blocks, or (2) multiple different Hadamard and/or Walsh transform-derived patterns.

### Claim 20 (depends on 13)

The method of claim 13, wherein if, within a specified number of iterations of step d) or a specified amount of time, said measured beam performance of a particular one of said second beams fails to reach a pass threshold or decreases significantly with respect to prior measured beam performance, or said particular second beam fails to correctly image features of said threshold size, then the corresponding column is inspected for defects and/or repaired and/or replaced.

### Claim 21 (depends on 13)

The method of claim 13, wherein steps b) through d) are repeated until the rate of improvement in measured beam performance and/or the rate of decrease in correctly imaged feature size falls below a threshold rate.

### Claim 22 (depends on 13)

The method of claim 13, wherein two or more of the blocks in at least one of said Hadamard targets are transposed within said Hadamard target.

### Claim 23

A substrate patterning and inspection tool, comprising:
one or more charged particle beam columns, individual ones of said columns configured to produce an individual charged particle beam, different ones of said columns having different writing areas; and
one or more column controllers storing instructions in a computer-readable non-transitory medium that, when executed, direct said beam controllers to:
control said columns to write multiple block-based Hadamard targets onto the substrate;
image said Hadamard targets;
calculate offsets for said columns in at least partial dependence on said image action; and
control said columns to write and/or image multiple features, said features being targeted in at least partial dependence on said offsets.

### Claim 24 (depends on 23)

The tool of claim 23, wherein said column controllers are configured to control said columns to write at least one Hadamard target in the writing area of each column performing said write and/or image multiple features action.

### Claim 25 (depends on 23)

The tool of claim 23, wherein said column controllers are configured to control different ones of said columns to perform said write actions and said image actions differently and simultaneously.

### Claim 26 (depends on 23)

The tool of claim 23, further comprising a substrate stage on which the substrate is mounted, wherein said column controllers are configured to calculate said offsets also in at least partial dependence on the design layout database of the substrate and the position of said stage.

### Claim 27 (depends on 23)

The tool of claim 23, wherein said features comprise line-cuts and holes.

### Claim 28 (depends on 23)

The tool of claim 23, wherein said image Hadamard targets action comprises initial-imaging expected locations of center and/or most-symmetric blocks of said Hadamard targets at least sufficiently to determine which portions of said Hadamard targets were imaged, calculating actual locations of said blocks in at least partial dependence on said initial-imaging, and refined-imaging at said actual locations.

### Claim 29 (depends on 23)

The tool of claim 23, wherein at least some of said Hadamard targets are high-order Hadamard targets.

### Claim 30

A substrate patterning and inspection tool, comprising:
one or more charged particle beam columns, individual ones of said columns configured to produce an individual charged particle beam, different ones of said columns having different writing areas; and
one or more column controllers storing instructions in a computer-readable non-transitory medium that, when executed, direct said beam controllers to:
control said columns to write multiple high-order block-based Hadamard targets in multiple writing areas on the substrate;
control said columns to image multiple features in said high-order Hadamard targets;
measure performance in at least partial dependence on said imaging, and determine which of said features were correctly imaged;
until one or more features of a threshold size are correctly imaged, modify beam parameters of said columns in at least partial dependence on said measuring to stochastically improve beam performance, and controlling said columns to repeat said image multiple target features action, said measure action and said determine action, targeting one or more features in said repeated image action that are smaller than those previously determined as correctly imaged; and
controlling said columns to image multiple features on the substrate using said columns with said modified beam parameters.

### Claim 31 (depends on 30)

The tool of claim 30, wherein said beam parameters are selected from: beam energy, beam focus, exposure time, beam current, beam landing energy, beam size, beam initial position, and beam scan rate.

### Claim 32 (depends on 30)

The tool of claim 30, wherein said measuring uses criteria selected from: beam resolution, contrast, signal-to-noise ratio, edge-sharpness, and deflection accuracy.

### Claim 33 (depends on 30)

The tool of claim 30, wherein said targets are generated using the discrete Hadamard and/or Walsh transform basis kernels using N≥10.

### Claim 34 (depends on 30)

The tool of claim 30, wherein said targets are configured such that, using initial and/or non-optimized beam parameters, at least some features of said targets can be correctly imaged and at least some target features cannot be correctly imaged.

### Claim 35 (depends on 30)

The tool of claim 30, wherein said image multiple target features action, said measure and determine actions, and said modify and repeat actions are repeated multiple times on one or more different substrates, prior to said imaging features action, using multiple different high-order Hadamard targets comprising either or both of (1) a high-order Hadamard target with transposed blocks, or (2) multiple different Hadamard and/or Walsh transform-derived patterns.

### Claim 36 (depends on 30)

The tool of claim 30, wherein if, within a specified number of iterations of said modify and repeat actions or a specified amount of time, said measured beam performance of a particular one of said columns fails to reach a pass threshold or decreases significantly with respect to prior measured beam performance, or said particular column fails to correctly image features of said threshold size, then said particular column is inspected for defects and/or repaired and/or replaced.

### Claim 37 (depends on 30)

The tool of claim 30, wherein said image multiple target features action, said measure and determine actions, and said modify and repeat actions are repeated until the rate of improvement in measured beam performance and/or the rate of decrease in correctly imaged feature size falls below a threshold rate.