LibreSilicon stack

LibreSilicon includes not only software but also a manufacturing process flow standard with recipes and machine designs. A detailed overview with links goes onto this page.

LibreSilicon can be roughly divided into two main categories, physical manufacturing as well as the tool chain part

Software

For doing anything useful with your foundry, you need a way of verifying your setup, for which we provide you the test wafer generator Danube River, then you need standard logic cells for synthesizing, placing and routing your layout, and of pad cells so that you can wire bond your chip;

Process Verification

When setting up a new foundry, no matter the scale, the physical manufacturing needs to be verified, using a test wafer, for this purpose we provide a dynamic test wafer generator named Danube River, which you can provide your own technology specs based on initial calculations for your setup and then verify and adjust your values until everything is correct.

Standard Cells

You need standard logic cells, small logic gate layouts made from place and routing discrete FETs, in order to turn the RTL level logic Yosys spits out into an actual digital chip layout.

Originally Philip was working on StdCellLib, but he re-licensed it under Apache which kind of defeats the purpose of a project calling itself LibreSilicon. Because Leviathan was a bit triggered by this due to his definition of Libre being the same as the Free Software Foundation, which means, that it's supposed under a GNU Public License, he decided to work on introducing the functionality for placing and routing standard logic cells in LibrePDK as well, in addition to analog and pad cell generation.

Pad Cells

The Pad Cell Generator is part of the LibrePDK and can be used to created custom sets of pad cells with custom rail voltages and you can even define a set of currents your pad frame is supposed to end up driving.

Pad Frames

An example of an early result of LibrePDK

Physical manufacturing

The physical manufacturing includes things like:

• Chemical processing
• Photolithography