Because IC layers are often incredibly thin compared to their horizontal X/Y dimensions, a true-to-scale 3D model can look completely flat. The 2.5D view includes a Z-scaling factor slider. Boosting this factor (e.g., multiplying Z by 5x or 10x) stretches the vertical axis, making it much easier to inspect stackups.
KLayout exposes its 25D functionality via Ruby and Python APIs. For advanced users, scripts can generate 25D snapshots for documentation or automated review.
, a popular open-source layout viewer and editor, provides a specialized feature known as the 2.5D View . This article explores what the KLayout 2.5D view is, its functionalities, and how to use it to debug and visualize your designs. What is the KLayout 2.5D View? klayout 25d view
For 95% of layout verification tasks, the 2.5D view provides exactly what engineers need: a fast, lightweight, and intuitive look at layer overlap and vertical connectivity. Key Benefits of Using 2.5D Visualization 1. Verification of Vias and Contacts
To get the most out of KLayout's 25D visualization tool, consider integrating these tips into your layout flow: Because IC layers are often incredibly thin compared
plane. Most KLayout 25D tools provide a . Bumping this factor up (e.g.,
: The feature uses OpenGL for real-time rotation and scaling. KLayout exposes its 25D functionality via Ruby and
| Tool | 25D Feature | Cost | Best For | |------|-------------|------|-----------| | | Extrusion-based, OpenGL, live update | Free (GPL) | Quick visual checks, MEMS, small-to-medium ICs | | Cadence Virtuoso 3D | True 3D with material properties | $$$ Commercial | Advanced node full-custom IC | | Magic VLSI | Wireframe 3D, no shading | Free | Academic, very old hardware | | OpenROAD | No native 25D; requires external renderer | Free | RTL-to-GDS flows | | Klive (KLayout extension) | Experimental voxel-based 3D | Free | Research-grade volumetric analysis |
Chemical Mechanical Polishing (CMP) requires uniformity. In a 2D layout, it’s hard to gauge density variation. The 25D view, when colored by layer height, gives a pseudo-topographic map. Rapidly alternating tall and short metal regions (poor density) looks like a mountain range, prompting dummy fill insertion.
It is not a full 3D simulator – and that is perfectly fine. For tape-out checks, MEMS topology inspection, and even client presentations, the 2.5D perspective offers the best trade-off between speed, clarity, and physical insight. With a few minutes of layer height assignment, you can see your design the way it will exist on silicon: as a three-dimensional object, not just a geometric abstraction.