The world’s first open source PDK Google did

The birth of a chip requires the steps of chip design, manufacturing, packaging and testing, in which chip design and manufacturing is the most core and difficult link, but relative to the design, due to financial and technical constraints, wafer manufacturing plants are more scarce. For anyone who wants to make a chip, you have two major obstacles to overcoming an RTL (resistance transistor logic circuit) that is already available: getting a process design kit (PDK) from a chip foundry, and having enough money to pay for the manufacturing.

The PDK, the Process Design Kit process design package, is a bridge between IC Design, Foundry, and EDA. PDK includes design rule sushers, electrical rules files, layout level definition files, SPICE simulation models, device layouts, and period customization parameters. PDK is a key step in transforming RTLinto into a physical chip, and an obstacle to open source of real processes, so to make your own chip, you need to have a manufacturable, open source PDK.

The world's first open source PDK Google did

But in the future, making your own chips will become possible. Recently, Tim Ansell, A software engineer at Google, announced the first ready-to-use, open source PDK with SkyWater. In addition, without incurring expensive manufacturing costs, Google will offer a completely free chip manufacturing process.

Free access to SkyWater PDK conditions

While Google’s free open source chips are available to everyone, there are certain conditions.

Users applying for free SkyWater PDK sdesigners must have their own designs open source, followed by a chip process limit of 130nm process nodes, and users need to upload an open source Git URL to efables.com. Eventually, Google will select a team of 40 users on the list of applicants, providing them with 10 square millimeter wafer molds and about 100 streams.

The world's first open source PDK Google did

In addition to offering a free chip manufacturing process, qualified teams don’t have to find their own foundry contracts, for which Google’s partner SkyWater will produce contracts.

SkyWater is a U.S.-based manufacturer of DMEA-certified integrated circuits and microdevices specializing in advanced innovative engineering services and mass production of various differential integrated circuits (ICs). In addition, SkyWater serves customers in the aerospace, defense, automotive, cloud and computing, consumer, industrial, Internet of Things and healthcare markets.

In chip manufacturing, the company took over in 2017 the fab founding plant originally owned by Cypress Semiconductor, which uses a conventional process of 130nm and 90nm and can also produce 65nm chips. At the same time, the plant focuses on manufacturing high-capacity, small-volume productions such as dedicated SRAM and mixed-signal circuits for IoT applications.

Regarding the specific production time, Tim said that “trial production” will begin in November for the first batch of selected, a second round of production in early 2021 and normal production in late 2021.

Some information about open source PDK

Currently, there are skyWater PDK open source documents on GitHub, and you can get some information about PDK.

The file description shows that SkyWater’s open source PDK content includes:

Comprehensive documentation of the design rules required to create manufacturable equipment on the SKY130 process node.

EDA tools support files for multiple open source and proprietary design processes.

Used to create the original cell library and model for the simulated design.

Multiple standard digital cell libraries that cover a range of different use cases.

Multiple document examples that use PDK.

The Sky130 is a proven 180nm-130nm hybrid technology originally developed in-house by Cypress Semiconductor and later owned by SkyWater Technology for general industrial use, and this collaboration between SkyWater and Google will extend it to everyone.

The world's first open source PDK Google did

The Sky 130 process node technology stack includes:

Supports internal 1.8V with 5.0V I / O (can operate at 2.5V);

Level 1 local interconnection;

Level 5 metal;

Inductor capacity;

has a high flaky rho polysilicon resistor;

Optional MiM capacitors;

Includes SONOS scaled-down batteries;

Support 10V regulated power supply;

High-pressure leakage extends NMOS and PMOS.

The Sky130 process nodes are flexible and offer designers a wide range of design options. Google says that if the Sky130 process node is successful, there will be more more advanced process nodes to choose from in the future.

However, GitHub’s PDK open source information is not all, and the content is still being updated.

Reference sources for this article:

https://fossi-foundation.org/2020/06/30/skywater-pdk

Open source address:

https://github.com/google/skywater-pdk