We need to make sure we can package the IC after the wafer has been diced into individual dies.

A common way of packaging ICs is to connect them to a leadframe by bonding tiny wires between the leads of the leadframe and the pads on the die.

The big bond pads around the outside of the IC often include ESD protection diodes, Input/Output drivers and so on.

This picture shows raven, an IC from Efabless. You can see around the edge there are the big bond pads and the power and ground lines. This structure is called a padring.

The padring used in the Google shuttle is included in Caravel.

Course feedback

Matt Venn's Zero To ASIC course is a real eye-opener to the possibilities of open source hardware. The course itself is a tour-de-force overview of almost all aspects of ASIC development from concept to GDSII. It's also great fun and regardless of your background or previous experience, you'll learn a lot and have a great deal of fun doing it. This course has inspired me to take the next step and submit my own design to efabless.

Mike Thompson (digital course)