KLayout
The layout tool behind the layout viewer, the layout checks and the picture on a share page.
KLayout is an open-source layout viewer and editor. It reads the GDS file a build produces and can display, measure and check it.
In this lab#
| Version | Inside the build: 0.29.4 on SKY130 and GF180MCU, 0.30.7 on IHP SG13G2, 0.30.12 on ASAP7 |
| Used for | Writing and checking the layout during the build, the layout viewer, and the picture on a share page |
In the build#
KLayout is one of two tools that write the final layout and run the design-rule check. The other is Magic. Running both, and comparing what they wrote with an XOR check, catches a mistake by either. Two exceptions: on GF180MCU, OpenLane 2.3.10 skips the KLayout design-rule check (Magic's still runs), and on ASAP7, a learning-only process, KLayout writes the layout but there is no sign-off design-rule check.
The layout viewer#
See the layout, or nelix layout, opens your layout in the browser.
| To | Do |
|---|---|
| Move around | Drag |
| Zoom | Scroll |
| Follow one layer | Hide the others in the layer list |
| See the cells | Zoom in until the rows resolve into individual cells |
What you are looking at#
| You see | It is |
|---|---|
| Horizontal bands | Rows of standard cells |
| Stripes across the die | The power grid, on the upper metal layers |
| Fine lines between cells | Signal wires, alternating direction by layer |
| Small squares at wire ends | Vias, joining one layer to the next |
| Shapes on the die edge | The pins of your top module |
The share picture#
The picture on a public share page is drawn from your real layout file by KLayout, in a container with no network access. Fill and filler cells are left out so the working logic stands out. The colours in that picture are chosen for clarity and differ from the viewer's.
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