2016 will prove to be a pivotal year in the history of semiconductor lithography. How do I know this? Because every year proves to be a pivotal year in the history of lithography. Why should 2016 be any different? Our industry moves too fast to allow a slack year.
I am frequently reminded of Sturtevant’s Law, not just because it is cute and funny (though it is), but because behind the humor lies a profound truth. Sturtevant’s Law says that the end of optical lithography is 6 – 7 years away. Always has been, always will be. When I started in the field of lithography way back in 1983, Sturtevant’s Law was as yet unformulated but nonetheless in full swing. X-ray or e-beam lithography was sure to take over by 1990 since it was obvious that optical lithography could not cross the 1 micron barrier.
This was but one of many, many failed predictions of the end of optical lithography. But the fundamental truth behind Sturtevant’s Law is this: we always know what we are doing for the next node (in 2 – 3 years), and are pretty sure about the node after that, but we have almost no visibility into what comes next. We know all of the unsolved problems looming beyond the 6 year horizon, and can’t quite picture the solutions. Sturtevant’s Law is a statement about our research and development timelines and how they relate to the pace of Moore’s Law.
But while Sturtevant’s Law has been in force for over 30 years, I’m afraid that it may be coming to an untimely end. The reason is simple: we no longer have good visibility out to two nodes (6 years). We have a just barely reasonable impression about what the next node will bring, and are sure that the node after that is impossible. The end of optical lithography is no longer 6 -7 years away, it is 2 – 3 years away, and even that time frame seems impossibly distant and opaque.
Our angst is about more than just lithography. Of course, we lithographers know that the industry moves to the pace that we set. Still, it is disconcerting to believe that a slowdown in lithography means the end of Moore’s Law. Yet that is what is at stake. In 2016, we must discover a path that keeps Moore’s Law moving forward, or watch Moore’s Law fall flat.
But a slowdown of Moore’s Law has already begun. Intel’s 14-nm node was a year late, and Intel has admitted that its 10-nm node will also be late, on a 3-year node pace rather than the historic 2-year cycle. TSMC has not admitted the slow-down, but is experiencing it anyway. They created a “faux” node, a 16-nm product line that has the same dimensions and density as the previous 20-nm node. Revealingly, when the 16-nm node came online last year, they did not report the revenues of that node separately as had been their normal practice, but rather began to lump the 16 and 20-nm node revenues together in one bucket. “Follow the money” was good advice coming from Deep Throat, and is good advice in the semiconductor industry as well.
Moore’s Law is slowing down because lithography is not keeping up. Multiple patterning is expensive and process control is a serious problem. No other solutions are available. Now, this where EUV is supposed to come in and save the day, right?
Alas, EUV is late. ASML has made very good progress in the last two years, but that progress has been enough to keep EUV late, not enough to catch up with the industry need. Anyone who has read these conference blogs before knows that I have been and continue to be an EUV skeptic. But for the first time in over 20 years of development, I finally see a glimmer of hope for EUV.
Time is the enemy of all lithography development programs. The demands of lithography move at an unrelenting pace, and even the slightest schedule slip in a lithography development program is the kiss of death. EUV is late, an almost unmistakable sign of failure, and yet finally there is hope. And here is the reason.
EUV was supposed to save Moore’s Law. But instead, the slowdown of Moore’s Law may save EUV.
The 10-nm node will be two years late compared to the original schedule (naming games aside), as we are now on a three-year Moore’s Law cycle. But since EUV is more than two years late, it still could not impact that node. How late will the 7-nm node be? Could it be late enough to use EUV? That is a distinct possibility.
The big picture of lithography is bigger than the picture we will see at the SPIE Advanced Lithography Symposium in 2016, since the big picture involves the macroeconomics of the semiconductor industry itself. But what we will see here this week is still big and very important. How painful is multiple patterning really? How close is directed self-assembly to being production worthy? What is the status of nanoimprint manufacturing for Flash production? Has there been any progress in taming the roughness beast? And of course, what about EUV source power?
There are always many questions coming into the start of the SPIE lithography conference. I am excited to start learning the answers.