Demo
1. Demo Overview
This page summarizes representative demo results for GeoSignal Preview.
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GeoSignal Preview starts from layout geometry, selects candidate ROIs for review, and generates rasterized masks, simplified Abbe-based aerial images, and multi-threshold contours for those selected regions.
The purpose of this demo is not to provide accurate process prediction or an optimized hotspot detector. It is to show how geometry-only review can be extended with optical-response and contour-behavior visualization.
The basic demo flow is:
Layout Geometry
-> Geometry-based Candidate Filtering
-> ROI Selection
-> Rasterized Mask
-> Abbe-based Aerial Image
-> Multi-threshold Contour
-> Hotspot-like Shape Review

The workflow can be understood in two parts:
Layout Geometry
-> Width / Space screening
-> Candidate ROI selection
Candidate ROI
-> Rasterized Mask
-> Aerial Image
-> Multi-threshold Contour
-> Hotspot-like Shape Review
This demo does not run optical simulation on every layout region. Instead, it first narrows down regions that may deserve review from a geometry viewpoint, then applies optical-model-based contour review to a limited number of ROIs.
Detailed implementation changes behind this workflow are recorded in Release Notes.
2. Candidate Selection in This Demo
In this demo, candidate regions are first identified from a minimum width / space viewpoint. Five ROIs are then selected for aerial-image and contour generation, matching the current service default.
The selected candidates should be understood as representative review examples, not final hotspot judgments. The exact screening rule and ordering method are preview-stage heuristics used to make the demo concrete and computationally manageable.
The important point is the review structure:
Find potentially weak locations from layout geometry
-> Calculate optical response at those locations
-> Review shape changes through threshold contours
The current snapshot uses the following reproducible conditions.
| Setting | Value |
|---|---|
| Input layout | sky130_fd_sc_hd_dfrtp_1.gds |
| Target layer / datatype | 67/20 |
| Width / space threshold | strict < 0.175 / 0.175 µm |
| Geometry engine | pya-native |
| ROI size / pixel size | 2.56 / 0.01 µm |
| Imaging | KrF 248 nm, NA 0.68, sigma 0.60, dense7 |
| Selected candidates | WIDTH_0001, SPACE_0001, WIDTH_0002, SPACE_0002, WIDTH_0003 |
The pya-native geometry engine and candidate ordering are summarized in the v0.6 Release Notes. Combined review GDS output, candidate-specific contour datatypes, and service memory changes are summarized in the v0.7 Release Notes. The optional focus/dose process-window workflow and its performance refactor are recorded in v0.8 and v0.8.1. The exact Hopkins cross-validation added in v0.9 does not change the Abbe-generated snapshot on this page; see the v0.9 milestone notes.
3. What This Demo Shows
This demo reviews the following items.
| Item | Description |
|---|---|
| Geometry-based Candidate | Candidate region first selected from minimum width / space in the layout |
| ROI Selection | Selected review region within the current runtime budget |
| Rasterized Mask | Binary mask generated by rasterizing layout polygons onto a pixel grid |
| Aerial Image | Optical intensity map calculated using a simplified Abbe-based imaging model |
| Multi-threshold Contour | Contours extracted at threshold levels 0.20 / 0.30 / 0.40 |
| Hotspot-like Shape Review | Visual review of necking, pinch, corner rounding, line-end pullback, and bridge-like behavior |
The key comparison is:
geometry-based candidate
vs
aerial-image-based optical response
vs
threshold-contour-based printed-shape-like behavior
The threshold contours used in this demo are not calibrated resist contours. They are qualitative visualization references for observing how the aerial image appears as contour behavior under different threshold levels.
4. Representative Candidate Results
The result below follows the same presentation order as the current Render interface. It was generated locally through the same service path because the public hosted instance is intended for lightweight interactive use.
Analysis Summary
Approximate Printed Metrics and Imaging Condition
Main Hotspot Overlay

The main overlay centers on WIDTH_0002, the selected ROI with the lowest valid direct-intensity width metric. It combines the aerial image, three threshold contours, the inner ROI, and the worst-width location.
Worst Printed Width and Space
WIDTH_0002.
SPACE_0001.Geometry Candidate Overview

The overview shows all merged width and space violation regions and the selected candidate anchors. A dense marker field is expected here: it is a geometry screening map, while the images above are the optical review results for the selected ROIs.
5. Common Interpretation Points
The summary, selected overlay, measurement zooms, and geometry overview should be reviewed together.
The main points to check are:
- whether edge blur or intensity spreading appears in the aerial image
- whether line-end pullback-like behavior appears near line ends
- whether corner rounding-like behavior appears around corners
- whether necking or pinch-like behavior appears around narrow-width regions
- whether bridge-like behavior may appear around narrow-space regions
- how much the 0.20 / 0.30 / 0.40 threshold contours move
- whether large contour movement aligns with the geometry-based candidate region
The philosophy of this demo is not to make a final hotspot judgment. It is to help reviewers quickly narrow down locations that deserve attention.
6. Current Scope and Limitations
The current demo is a qualitative visualization result for public preview.
It has the following limitations.
- The width / space screening criterion is a preview heuristic, not a calibrated process rule.
- The candidate selection method is not an optimized hotspot-ranking logic.
- Only a small number of representative ROIs are shown due to runtime considerations.
- A simplified Abbe-based imaging model is used.
- Wafer-data-based calibration is not included.
- Resist and etch models are not included.
- Threshold contours are used for qualitative comparison and visualization.
- CD prediction accuracy is not the goal.
- Public or synthetic examples are used.
- Use only public, non-confidential GDS/OAS files with the live demo.
- Core implementation code is not included in this public preview repository.
Therefore, the current results should be interpreted as:
qualitative visual indicators
not as:
production specifications
7. Feedback Points
Feedback is especially helpful for the following points.
- whether multi-threshold contour helps understand contour sensitivity
- whether hotspot-like shape observation is intuitive
- whether observing necking, corner rounding, line-end pullback, and bridge-like behavior is useful
- what additional pattern cases would make the preview clearer
Share feedback through the GeoSignal Preview form