I am pleased to introduce you to IntSim v2.0 today. IntSim v2.0 is a CAD tool to simulate and optimize monolithic versions of 2D and 3D-ICs.
Some background on IntSim
I first began work on IntSim during my PhD studies at Georgia Tech almost 5 years back. We folks in Prof. James Meindl's research group had derived compact models for various device and interconnect phenomena. There was opportunity to combine together all these models to get a chip simulator. IntSim v1.0 was the result. It could simulate 2D-ICs and we described it in ICCAD 2007 in San Jose (I had just got married... my wife was based in San Jose while I was based in Atlanta finishing up my PhD, so I liked attending conferences in the San Jose area!). Over the past 5 years, a number of university researchers and professors have used IntSim v1.0 :-) Some used it to evaluate chip-level performance/power benefits of novel transistor technologies, some used it as an architecture simulator, and others used it to set homework assignments for classes they taught.
Well, I joined NuPGA/MonolithIC 3D Inc., and we were coming up with some great new ways to do Monolithic 3D-ICs. The question we began asking ourselves was: how does going to monolithic 3D impact chip performance, power and die size? We couldn't design an actual monolithic 3D chip since CAD tools for this were still under development. So, I suggested to Zvi Or-Bach, our CEO, that hey, there was this CAD tool I built for 2D-ICs at Georgia Tech, I can extend it to monolithic 3D using 3D wire length distribution models in the literature. Zvi liked the idea, and suggested I go ahead. He also said, "Let's offer it on our website for people to use, let them play with it and have fun simulating monolithic 3D chips too". Thus began the efforts for IntSim v2.0.
Structure of IntSim v2.0
You can see a diagrammatic representation of IntSim v2.0 below. For a detailed account of models used in IntSim v2.0, please visit the "IntSim's models" page. There are a few key improvements compared to IntSim v1.0:
- Support for monolithic 3D-ICs: Signal wire length distributions for monolithic 3D are obtained using Arif Rahman's models (link to Arif's PhD thesis in MIT). I extended Kaveh Shakeri and Reza Sarvari's models for power distribution to 3D, and developed my own models for 3D heat removal... I'll talk more about the 3D heat removal models once they're published.
- Java and Open-Source: IntSim v1.0 was written in MATLAB, and required a (somewhat costly) MATLAB license :-( IntSim v2.0 is in JAVA, so you can run it as an app on any OS: Windows, Mac OS X or Unix. The tool is very well-documentated, and is Open Source. So, if you feel you'd like to contribute and improve IntSim v2.0, please let us know. We'll give you the source code of IntSim v2.0, you can add in your features... we can then release your features in IntSim v3.0 and list you as a contributor to the tool.
Want to run IntSim v2.0 and check it out?
It's simple! Double-click on the icon below to run a beta version of IntSim v2.0.
You can use IntSim v2.0 for a number of things: simulate 2D and 3D-ICs, determine scaling trends and get estimates for quantities such as die size, pitches of metal levels in a multilevel interconnect network, chip power and clock frequency prior to design. What excites me the most is that some professors are using IntSim as a fun way for students to learn how a chip works. For example, they set homework assignments asking students to use IntSim and find out how chip power and the interconnect stack changes as a function of clock frequency - this helps students appreciate and understand why clock frequency increases in the future are not that attractive. The picture below shows some common uses of IntSim.
Comparison with Actual Data from a Commercial Microprocessor and case studies showing use of IntSim v2.0
Please check out our "comparison with actual data" page and our "case studies" page.
We are building a small group in our company to develop open-source CAD tools for 3D-ICs. We'll add more features to IntSim moving forward, and we also plan to develop other 3D open-source CAD tools... It is clear to us that having good CAD tools and simulators will accelerate the industry's transition to Monolithic 3D.
Many thanks to Zvi Or-Bach, MonolithIC 3D Inc.'s CEO, for supporting development of IntSim v2.0 and for various useful inputs. I'd also like to thank Prof. James Meindl of Georgia Tech under whose guidance most of the models in IntSim were developed. Jeff Davis, Ragu Venkatesan, Arif Rahman, Keith Bowman, Kaveh Shakeri, Reza Sarvari, Azad Naeemi, Ajay Joshi and several others helped with useful discussions while developing IntSim... I'd like to thank them for their help.