Klayout 25d View -

Seeing the Bigger Picture: A Guide to KLayout’s 2.5D View

For decades, integrated circuit (IC) layout engineers have relied on two-dimensional, top-down views to design chips. But as process nodes shrink and designs grow in complexity, a purely planar perspective often obscures critical relationships between layers. This is where KLayout’s 2.5D view comes into play.

Case Study: Diagnosing a Missing Implant Layer

Consider a real-world scenario. A design engineer runs LVS (Layout vs. Schematic) and receives a mismatch in an analog block. The error points to an NMOS transistor that should have an N-well implant but does not. The 2D view shows overlapping polygons, but the hierarchy is deep. klayout 25d view

Just a reminder that Klayout has a built-in 2.5D view (View → 2.5D View). Seeing the Bigger Picture: A Guide to KLayout’s 2

Define Extrusions: Use the following functions in your script: z(layer, options): Extrudes a specific DRC layer. Limitations and Critique While impressive, the 25D view

How KLayout implements 2.5D (conceptual)

Layers are assigned thickness/height and optionally material or color.
The renderer extrudes polygons vertically and shades faces and edges to convey depth and occlusion.
Boolean-like effects: stacked polygons on the same XY footprint combine into continuous extrusions; overlapping polygons at different layer heights create visible steps and cliffs.
Lighting and viewpoint controls create relief-like rendering; transparency helps examine buried features.

Limitations and Critique

While impressive, the 25D view has specific limitations that users must understand to avoid errors.

Optionally, assign a base z-level (starting vertical position) for layers that are not planarized.

This data transforms a flat GDS file into a structured stack, allowing the software to understand that "Layer 1" is physically below "Layer 2."

Report: Evaluation and Functionality of KLayout 2.5D View Mode