Semiconductor, packaging & electronics

Line edge & width roughness (LER / LWR)

Line edge and line width roughness as 3-sigma deviation along patterned lines.

ModalitiesTop-down SEM
SEM of patterned silicon lines showing the rough, wavy edges measured as line-edge roughness
3.4 nm
LWR 3 sigma
24 nm
Correlation length
120
Lines

Example outputs shown for illustration. Numbers depend on your samples and protocol.

Image: NIST, public domain via Wikimedia Commons

Results

Each measurement below comes from your own images, tied back to the annotated frame it came from, so results stay comparable across samples, locations, and conditions.

per area

LER (3 sigma)

Findings placed in sample coordinates to reveal spatial patterns and local density.

LWR 3 sigma3.4 nm
Bottom
64%
Corner
71%

Example, not a claimed result

In your report: Coordinate-referenced map, regional density, and representative images.

per area

LWR (3 sigma)

Findings placed in sample coordinates to reveal spatial patterns and local density.

Illustrative shape
Bottom
64%
Corner
71%

In your report: Coordinate-referenced map, regional density, and representative images.

per area

Edge profile

Findings placed in sample coordinates to reveal spatial patterns and local density.

Illustrative shape
Bottom
64%
Corner
71%

In your report: Coordinate-referenced map, regional density, and representative images.

per area

Power spectral density

Findings placed in sample coordinates to reveal spatial patterns and local density.

Illustrative shape
Bottom
64%
Corner
71%

In your report: Coordinate-referenced map, regional density, and representative images.

per area

Per-line table

Findings placed in sample coordinates to reveal spatial patterns and local density.

Lines120
Bottom
64%
Corner
71%

Example, not a claimed result

In your report: Coordinate-referenced map, regional density, and representative images.

Built around your image set

Use the calibrated images your team already collects, together with the locations you need to compare.

01
Representative images
Provide representative top-down sem images with a recorded scale calibration and the regions of interest clearly visible.
02
Image capture details
Record instrument, magnification, pixel scale, preparation method, and the smallest feature the review must resolve.
03
What to compare
State the samples, number of fields, and conditions to compare. A single field of view is not treated as a whole-sample result by itself.

Each report includes

The artifacts your team receives, ready for review and archive.

Annotated image set

Original images with regions of interest, measurement points, masks, and finding overlays.

Measurement table

Location-indexed values, units, distributions, and QC flags in a structured export.

Method record

Calibration evidence, analysis settings, version history, and validation summary.

Confidence in every resultTraceable measurements, reviewed against your agreed reference method.
Traceable scale
The report records the image scale, calibration evidence, and a method-specific expanded measurement uncertainty. It does not use one product-wide accuracy number.
Reference comparison
The configured method is compared with your accepted reference method or reviewed annotations, and reports bias by measurement range and image condition.
Detection performance
Detections are evaluated against reviewed reference regions with precision, recall, and segmentation overlap, separated by the conditions that affect performance.
Repeatability
The locked protocol is rerun on the same inputs and on a defined repeat set. The review records variation from image acquisition, sampling, and analysis separately where possible.

What this result does not establish: Computes roughness statistics from detected edges in your image. Values depend on pixel size and edge-detection settings; hold them fixed to compare across samples.

The measurement, today

Edge roughness is estimated by eye or from a short manual trace. The sampling is too small to be stable, and the number depends on who drew the trace.

What it costs

Roughness that survives to the transistor gate spreads threshold voltage across a die. At advanced nodes it is a direct performance and yield limiter, and it is invisible to a coarse CD measurement.

From image to reviewed result

  1. 1

    Image the lines

    Load top-down SEM images of the patterned lines.

  2. 2

    Extract the edges

    Both edges of each line are traced sub-pixel along the full imaged length.

  3. 3

    Compute deviation

    Edge position deviation gives LER; width deviation gives LWR, each as a 3-sigma value.

  4. 4

    Report the spectrum

    A power spectral density and correlation length accompany the per-line table.

Talk to a scientist

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