Lithography on a Greek Island

45th International Conference on Micro and Nanoengineering (MNE 2019)
by Chris Mack

Isle of Rhodes, Greece , September 23-26, 2019

I have a confession to make.  Sometimes I choose to go to a conference mostly based on its location.  My core conference is SPIE’s Advanced Lithography, and I would go to that wherever it was (San Jose is nice, but it is not a “destination”).  But there are a number of conferences at the periphery of lithography, and in particular conferences that touch on lithography for the academic community.  Three conferences that fit this bill are the Electron, Ion, and Photon Beam Technology and Nanofabrication conference (EIPBN, often called 3-beams or triple beam) in the US, Microprocesses and Nanotechnology Conference (MNC) in Asia, and Micro and Nano Engineering (MNE) in Europe (thought of as sister conferences).  They can be interesting, informative, thought provoking, and even inspiring.  But often there is little of direct relevance to my current focus.  In other words, I don’t need to go, but sometimes I want to go.  How much I want to go depends on where it is.

This year, the MNE conference was on the island of Rhodes, Greece, and guess what?  I wanted to go.

These three conferences, EIPBN, MNC, and MNE, used to have a lot more lithography content, much of which was relevant to semiconductor lithography.  Today, however, semiconductor lithography has priced itself out of the academic market, and universities employee either vastly outdated lithographies, or high-resolution approaches that are so slow they could never be considered for the semiconductor industry.  Still, it is always nice to find out what the academic research community is up to in the world of lithography.

But frankly, for me, it is generally not worth traveling half-way around to world to go to one of these conferences.  Unless I want to.

And so I found myself this week in Rhodes, Greece, listening to interesting papers, presenting one myself, and enjoying the amazing beauty and heritage of the one of the Greek islands.

The MNE conference is extremely vibrant, with a lot packed into three days:  150 orals, 360 posters, and four evenings of social activities.  Student participation is huge (often the point of an academic conference), and as an old, cynical industry guy, it is refreshing to be around enthusiastic young people.

The plenary session started with an old friend – Yan Borodovsky, retired from Intel, who talked about Moore’s Law: Past, Present, and Future.  As he told me after, “I can’t believe I am still being asked to speak when in my 5th year of retirement!”  For a retired guy, he gave a great talk.  His “past” described the three pillars of microelectronics:  Von Neumann’s computer architecture of CPU, memory, and I/O, Moore’s Law of reducing transistor costs, and Dennard scaling that makes a transistor better when it is smaller.  One by one these pillars of microelectronics are falling away.  Dennard scaling ended in the mid-2000s when voltage scaling became increasingly difficult.  Smaller transistors are no longer better, we just hope they are not terribly worse.  Moore’s Law has dramatically slowed of late, and Yan made a bold prediction – the end of reduced cost per transistor would occur in 2021, coinciding with the attempt to bring EUV lithography into high volume (really high volume) manufacturing.  The last pillar, Von Neumann’s architecture, is the hardest to escape given its phenomenal success.  But current high-performance computing is limited both by the speed and power consumption associated with transferring data back and forth from memory to CPU.  New architectures, such as neuromorphic computing, could redefine these limits.

Yan’s main point was that lithography choices have always been based on the constraints of these three pillars.  He added one further important constraint:  that today’s logic chips (such as CPUs, GPUs, and Application Processors) are seriously defect intolerant.  One defect (for example, one missing contact hole) will kill an entire chip.  This reality rules out any lithography approach with defect densities greater than about 0.1 defect/cm^2.  That’s a shame, since lithographies such as directed self-assembly (DSA) and nanoimprint lithography (NIL) are high resolution and cheap, but don’t have the defect densities required for today’s logic devices.  A change to a computing architecture that is fundamentally defect tolerant would enable lower-cost lithography choices.  Since today’s chips have 50% or more of their cost coming from lithography, the impact would be huge.  It was clear that Yan is hoping for a defect-tolerant future, so that lower-cost lithography approaches become practical.  As am I.

There were only a few other talks specifically relevant to semiconductor folks like me.  B.T. Chan of imec talked about the etch challenges that come with making FinFETs with only one or two fins.  Michal Danek of Lam Research talked about atomic layer deposition and atomic layer etching as enablers to 3D NAND devices.

The social interactions of the conference were some of the highlights for me.  The reception Monday night before the start of the conference brought us to crusader-era architecture (the Knights of Saint John ruled the island from about 1300 to about 1500) in the old town of Rodos (Rhodes).  It was lovely, and included Homeric singing (what a treat).  Tuesday night was a beach party (we could see Turkey from the beach).  Wednesday night was the conference reception, and I had the honor of serving as a judge for the very popular Micrograph contest.  John Randall began the micrograph competition at the 3-beams conference in 1995, and he brought it to MNE in 2005.  This year there were over 60 entries, and the judging was hard.  You can find this year’s micrographs at

The conference ended Thursday night with a bus trip to Lindos, an ancient and beautiful city.  A fitting end to a conference defined, for me, by its location.


Chris Mack is a writer and lithographer in Austin, Texas.

© Copyright 2019, Chris Mack.

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