Klayout 25d View
allows you to visualize a 2D layout in 3D by extruding layers vertically based on a script
. This is particularly useful for verifying material stacks, such as MEMS devices or CMOS metal layers. 1. Prerequisites OpenGL Support
: KLayout must be compiled with OpenGL support for the 2.5D viewer to work. Performance Limits
: It is optimized for small to medium designs; a practical limit is roughly 100,000 polygons Layout Setup : Ensure you are in Editor Mode if you need to create or modify layers first. 2. Getting Started
To generate a 2.5D view, you need a script that defines the material stack using a specialized version of the KLayout DRC language Navigate to New 2.5d Script This opens the Macro Editor with a template script. Define your layer stack using the functions. 3. Scripting Basics The script tells
how high each layer should be extruded and at what starting point in the Z-axis z(layer, options) : Extrudes a specific layer. : The elevation where the extrusion begins. : The thickness of the material. zz(options) block : Combines multiple
statements into a single display group for complex material geometries. Example Script:
# Extrude Layer 1/0 starting at Z=0.1um with a thickness of 200nm ), zstart: .um, height: # Extrude Layer 2/0 for 300nm on top of previous layers ), height: Use code with caution. Copied to clipboard 4. Running the View : Click the button in the Macro Editor or select your script from the Window Management
: Once run, the 2.5D window will pop up. If closed, re-open it via Open Window Visibility Follows Selection
: You can enable this option in the viewer settings to only show the 3D extrusion of parts you have selected in the 2D layout. 5. Troubleshooting Script not showing in menu
: Check if the script is configured to be "bound to a menu item" in the Macro Development environment Window is blank : Ensure your
values are not zero and that you have valid shapes on the specified input layers. complex script example involving multiple material groups or specific 3D navigation shortcuts? The 2.5d View - KLayout Layout Viewer And Editor
The 2.5d View in KLayout is a feature that creates a pseudo-3D representation of your layout by extruding 2D layers into vertical blocks. It is primarily a visualization tool used to inspect complex multi-layer structures like via stacks. Key Requirements
OpenGL Support: Your version of KLayout must be compiled with OpenGL support to use this feature. klayout 25d view
Performance Limits: It is currently optimized for sections of a layout, with a practical limit of roughly 100k polygons.
2.5d Script: To generate the view, you must use a specialized script—a variant of a Design Rule Check (DRC) script—that defines how each layer is extruded and positioned on the z-axis. How to Use the 2.5d View
Create a Script: Navigate to Tools > 2.5d View > New 2.5d Script to open a template in the macro editor.
Define Extrusions: Use the following functions in your script: z(layer, options): Extrudes a specific DRC layer.
zz(options) block : Groups multiple z statements into a single material for easier display management.
Run the View: Click the Run button in the macro editor or select your script from the Tools > 2.5d View menu. Adjust the Scene:
Z-Scaling: Use the right slider in the 2.5d window to exaggerate the vertical (z) axis, making flat profiles easier to see.
Colors/Visibility: The 2.5d view inherits colors and visibility settings directly from your active Layout View. Navigation Controls Action Rotate (Azimuth/Elevation) Drag with Right Mouse Button Move Pivot (X/Y/Z) Drag with Middle Mouse Button Pivot Forward/Backward Mouse Wheel Zoom Layout Ctrl + Mouse Wheel Snap to Top View Hold Shift Key
For more advanced needs like tapered etch profiles or rounding, users often look to external tools like xView or the integrated xsection tool, as the native 2.5d feature only supports straight vertical extrusions. Colors in the 2.5d View - KLayout Layout Viewer And Editor
Conclusion
KLayout's 25D viewing capabilities offer a powerful way to visualize and analyze 2D layout data with a third dimension. By mastering its features and leveraging the community and scripting capabilities, users can significantly enhance their workflow and insights into semiconductor designs. Always refer to the most recent documentation and community forums for the latest features and best practices.
Unlocking the KLayout 2.5D View: A Comprehensive Guide KLayout's 2.5D View is a specialized visualization tool that transforms flat 2D mask layouts into semi-3D representations through vertical extrusion. Introduced in version 0.28, this feature allows designers to inspect the vertical stack of a semiconductor process, helping to visualize wiring congestion and relative material heights. What is 2.5D View?
Unlike a true 3D viewer that might support arbitrary angles and curved surfaces, the 2.5D view in KLayout works strictly by taking 2D polygon layers and extruding them vertically. It cannot model complex process topologies (like conformal coverage) but excels at showing how different metal, poly, and diffusion layers sit on top of each other. Key Technical Requirements
OpenGL Support: The 2.5D view is only available if your KLayout build was compiled with OpenGL support. allows you to visualize a 2D layout in
Performance Limits: Currently, the tool has a practical limit of approximately 100,000 polygons. Setting Up Your First 2.5D Scene
To use this tool, you must provide a script that defines the "material stack"—essentially telling KLayout which layers to extrude and to what height.
Create a New Script: Navigate to Tools > 2.5d View > New 2.5d Script. This opens the macro editor with a template based on the Design Rule Check (DRC) language.
Define Extrusions: Use the z function to define layer heights.
z(layer, zstart: 0.0, height: 1.0): This extrudes a specific layer from a base (zstart) to a certain thickness (height).
zz ... : This combines multiple z statements into a single display group for easier material management.
Run the Script: Click the "Run" button in the macro IDE. A new 2.5D window will appear, rendering the section of the layout currently visible in your main viewer. Navigation and Controls
The 2.5D window uses a camera-based navigation system relative to a pivot point marked by a compass icon. Rotate (Azimuth/Elevation) Drag with Right Mouse Button Move Pivot (Up/Down/Left/Right) Drag with Middle Mouse Button Move Pivot (Forward/Backward) Mouse Wheel Zoom (Magnify/Shrink) Ctrl + Mouse Wheel Top-Down View Toggle Press and Hold Shift Scaling the Z-Axis
Because semiconductor layers are often very thin relative to their width, the 2.5D view includes a Z-axis zoom slider on the right side of the window. Increasing this factor exaggerates the vertical dimensions, making it easier to see height variations that would otherwise appear flat. Advanced Visualization Features
Layer Syncing: The 2.5D view respects your 2D layout settings. If you change a layer's fill color or hide it in the main viewer, it will update in the 2.5D window.
Material Visibility: A dedicated list on the right allows you to toggle specific material groups on or off, which is useful for "peeling back" upper metal layers to see lower-level transistor structures.
Net Highlighting: By exporting a net from the Net Tracer, you can visualize a specific electrical path as it moves vertically through vias and different metal layers. Colors in the 2.5d View - KLayout Layout Viewer And Editor
The KLayout 2.5D View is an advanced visualization feature that extrudes 2D layout polygons into a pseudo-3D space. Introduced in version 0.28, it allows designers to inspect vertical relationships in a process stack, such as via alignments and metal layer overlaps, without the complexity of a full 3D CAD environment. Core Concept: Why "2.5D"? ensure libgl1-mesa-glx is installed. On Windows
While it looks 3D, the view is technically "two and a half dimensional" because it represents layers as vertically extruded solids with a fixed thickness. It does not model complex process topologies like step coverage or planarization effects, but rather focuses on the relative vertical dimensions of the material stack. Key Features and Capabilities
Vertical Visualization: Ideal for spotting "via stacks" or identifying missing connections between metal levels that are difficult to see in a flat 2D view.
Net Tracing Integration: Users can export a net from the KLayout Net Tracer and view it in 2.5D, making it easier to follow a signal as it moves up and down through the stack.
OpenGL Powered: The feature uses OpenGL for real-time rotation and scaling.
Practical Limits: The current implementation handles approximately 100,000 polygons before performance significantly degrades. How to Use the 2.5D Viewer
To use this feature, KLayout must be compiled with OpenGL support. 1. Creating a 2.5D Script
The viewer relies on a script (a variant of a DRC script) to define the material stack. Go to Tools > 2.5d View > New 2.5d Script.
Define layers using the z function. For example, to extrude Layer 1 (thickness 200nm) and Layer 2 (thickness 300nm):
# Start Layer 1 at 100nm elevation with 200nm height z(input(1, 0), zstart: 0.1.um, height: 200.nm) # Add Layer 2 for the next 300nm z(input(2, 0), height: 300.nm) Use code with caution. 2. Navigation Controls
Navigation revolves around moving a camera relative to a pivot point marked by a compass icon. Mouse/Keyboard Input Rotate (Azimuth/Elevation) Right-click and drag Move Pivot (Translate) Middle-click and drag Zoom (Magnify Layout) Ctrl + Mouse Wheel Top-Level View Hold Shift key Practical Applications
Educational Use: It is highly valued for training new designers to understand the physical reality of a GDSII/OASIS file.
DRC/LVS Debugging: When a Layout vs. Schematic (LVS) error indicates a floating net, the 2.5D view can help visually confirm if a via is physically missing between two metal layers.
Interposer Design: Useful for visualizing advanced packaging structures like silicon interposers that connect multiple dies. 5D script for a specific process like Sky130? Colors in the 2.5d View - KLayout Layout Viewer And Editor
Step 1: Verify OpenGL Support
The 25D view relies on OpenGL. On Linux, ensure libgl1-mesa-glx is installed. On Windows, the standard install includes software emulation, but hardware acceleration is recommended. In KLayout, go to View > 2.5D View. If grayed out, your build lacks OpenGL.
5. Advanced Features
- Measurement Tools: Use KLayout's measurement tools to quantify distances and heights in your 25D layout.
- Cross-Section Views: Some versions of KLayout and its plugins offer the capability to view cross-sections of your layout, providing a more detailed look at specific areas.