Future EUV/FEL Strategy – The Beam Line Approaches

As many of you know, I've been following the progress of EUV lithography over the years, observing and commenting on the program's many engineering successes as well as the delays in the convergence of EUV lithography and the anticipated HVM time line (High Volume Manufacturing). In spite of improvements in laser technology and the availability of low dose photoresists, the development of high power LPP (Laser Produced Plasma) EUV source technology >100 watts remains problematic. EUV HVM insertion remains elusive and unpredictable. The source power limitations and MTBF (Mean Time Between Failure) of LPP technology have gated the program. A few years ago many in the SPIE community sought to explore the potential of a FEL source for high power EUV applications. At the time, Free Electron Laser [1] Technology was not yet a topic for dinner table discussion so in September, 2014 I published Future FEL/EUV Strategy – The Light at the End of the Beam Line. [2] On-going FEL developments at SLAC and recent related commentary from companies like GLOBALFOUNDRIES have generated new interest in FEL technology. As many new engineers and investors have joined our ranks, I thought a more comprehensive review was in order, so I've excerpted portions of my 1994 primer on FEL/EUV strategy to point out the enabling feature/benefits of a high power, high reliability light source for EUV lithography.

What are the current obstacles to high power EUV?

In ASML's current LPP source designs, a solid state "pre-pulse" laser and a second, high energy CO2 laser are fired at micron sized tin (Sn) pellets, evaporating them and releasing EUV light as a byproduct. Knowledgeable sources have informed me that the currently employed CO2 lasers are at or near the maximum of their pulse rate capabilities, effectively limiting further power output. As more CO2 laser power becomes available, there may still be practical limitations on the scaling and feed rate of Sn (tin) target material. As determined by physics, the inherent energy conversion factor for tin approximates 4%, and further incremental improvements in efficiency are obtained with diminishing returns. Assuming additional laser power becomes available for ASML, further complications can result from higher LPP source power levels as the rate of residual particulate contamination from evaporated tin increases in approximate proportion with increased laser power. Critical beam line mirror surfaces and other source components rapidly lose their efficiencies as tin contamination accumulates, reducing the available up time of the stepper (MTBF). It was originally anticipated that an optimal LPP EUV source design would provide 13.5nm light at power levels >200 watts, providing current and future lithography requirements. However, more recent demands for even higher EUV power levels have been identified. ASML and Carl Zeiss acknowledged in an invited paper at SPIE Advanced Lithography 2015, that higher resolutions will require 60mJ/cm2 for half pitch nodes <8nm. [3] ASML's recent (2015) collaboration with Carl Zeiss has produced an optical system with a numeric aperture (NA) of 0.55 vs. ASML's current EUV NA of 0.33. The higher NA system will require 500 watts of EUV power to achieve the estimated 60 mJ/cm2 dosimetry required for throughput of 150 wafers/hour. While this concept extends the viability of 13.5nm lithography, the delivery of a reliable 500 watt EUV source remains a critical item on the agenda, meaning the availability of free electron laser technology will probably gate related programs. A recent article appearing in the SPIE News Room, Extending extreme-UV lithography technology, [4] suggests that power levels of 500 – 1000 watts may be required for a single stepper necessitating a large scale central source EUV FEL.

A Primer on Free Electron Lasers

What is a free electron laser and how is it different from conventional lasers and LPP systems? To answer this question we must entertain the convergence of the US DOE's high energy physics community with the semiconductor industry and discuss recent innovations in technology. In previous and current generation stepper and scanner systems, it's been common to utilize laser light sources producing the desired wavelengths required for semiconductor photolithography. In current 193nm lithography systems, an argon fluoride (ArF) laser produces the light. The laser light produced is monochromatic, of sufficient brilliance and provides many hours of trouble free uptime. It would seem this simplistic approach might be applied to EUV lithography. Why not build an EUV laser with a wavelength of 13.5 nanometers? This has not been possible due to limitations in physics. The highly reflective optics required for laser efficiencies have yet to be created for EUV spectra. Current Bragg cell mirrors reflect EUV with a closely approximated 90% efficiency. However, FEL is a game changer. Some history and an analogy:


The term LASER is an acronym for Light Amplification by Stimulated Emission of Radiation. The first solid state, 694nm synthetic ruby laser produced at Hughes Research in 1960, [5] utilized xenon flash lamps to inject high energy photons throughout the core of a ruby rod, stimulating the emission of photons from its lattice structures. Lasers operate at specific wavelengths which are determined by the seed (or lazing) material's inherent spectral signature. The 694nm wavelength is derived from the band gap emissions of the ruby's crystalline composition. We might compare the ruby crystal in this laser with a quartz crystal in a radio which determines its operational frequency. Accordingly, we might otherwise assign “channel I” as an identifier of I-line photolithography operating at 365nm.

The Foundation Physics of FEL

 A Radio Logical Analogy

A radio transmitter's frequency has historically been controlled by quartz crystal elements. Y-cut quartz crystals oscillate (vibrate) at specific frequencies which are dependent upon their thickness. The thinner the crystal, the higher the frequency obtained. Inversely, the thicker the crystal, the lower the frequency obtained. Passing an electric current through a quartz crystal induces it to oscillate at its inherent resonant frequency, so determined by its thickness. The frequency produced is extremely stable and the resulting wave form is of high purity, providing an excellent medium for control of radio frequencies and instrumentation. Crystals also produce harmonic frequencies. A harmonic is a multiple of the crystal's fundamental resonant frequency. As such, a crystal oscillating at 3 MHz will also produce a weaker signal at 6MHz (its second harmonic frequency), and a still weaker third harmonic at 9MHz and so on. When impractical to manufacture crystals at their desired fundamental frequencies, "third overtone" crystals are often utilized to provide a harmonic frequency which can be sufficiently amplified and utilized as an effective fundamental frequency, thus extending the upper limits (and our usage) of the radio spectrum. Even with clever engineering, over the years radio frequency control became problematic as multi-channel communication systems evolved, requiring large banks of crystals to span a given range of frequencies; one crystal required for each channel frequency. Rather than utilize thousands of crystals to span the radio spectrum, communications equipment evolved to employ a frequency control device called a VFO: a Variable Frequency Oscillator. In this scenario, several fundamental frequency crystals and specially designed varactor diode/phased locked loop circuits comprise a heterodyne oscillator, sometimes known as an IF (Intermediate Frequency) mixer. Such an oscillator can generate a wide range of possible frequency combinations by mixing (heterodyning) the output obtained from the crystals to produce the desired sum/difference of their frequencies by way of constructive or destructive interference. As a VFO radio tuning dial is manipulated, it changes one of the mixing frequencies to produce the desired sum/difference operational frequency for both transmitter and receiver. The advantage to such a design is the elimination of separate transmitter/receiver controls, and thousands of individual crystals normally assigned for each desired radio channel. The conceptual use of both harmonic and sum/difference frequency synthesis has found its way into many applications in physics and electronics.

Free Electron Laser Fundamentals

Imagine that we might adjust and control a laser's wavelength using a concept similar to a radio's Variable Frequency Oscillator but with a different set of physics. By electronically tuning a laser's wavelength, we can eliminate the need for specialized crystalline, gaseous or other lazing materials and operate outside the spectral wavelength segments they are physically limited to. FEL technology can produce tunable wavelengths of light throughout the microwave, visible spectrum and x-ray regime. A free electron laser is comprised of a large beamline/electron source which accelerates electrons to near the speed of light. On opposite sides of the electron beam line are interposed field coils of opposing polarity called undulators or "wigglers", which when energized establish a transverse sinusoidal field across the beam path. Electrons accelerated into the transverse field produce incoherent photons in a mixed assortment of sinusoidal wavelengths sometimes referred to as “bunches”, emitting photons at wavelengths determined by their acceleration and the transverse field strength (synchrotron radiation). By adjusting the electron beam energy or the magnetic field strength of the undulators, the wavelength of the emitted photons can be tuned selectively to produce coherent light. Variations on this concept have evolved as follows:

A Tunable SASE FEL

A SASE FEL is able to produce laser light over a broad range of spectrum without the requirement for conventional lazing materials such as ruby crystal or argon fluoride etc. In a tunable SASE (Self Amplified Spontaneous Emission) FEL, high energy source electrons passing through an undulator can produce an assortment of incoherent photons (initially at randomly different wavelengths) which become bunched in the transverse sine wave and interact via constructive or destructive interference, producing incidental derivative wavelengths (spontaneous emission). That is to say the bunched photons add and subtract their wavelength values from one another producing new sum/difference valued photons at the mathematically resulting wavelengths. When tuned to a specific wavelength of interest by adjusting the electron beam energy or the magnetic field strength of the undulators, such subsequently produced photons arrive in phase (at the same wavelength) and cumulatively intensify to release high energy coherent laser light (self amplification). While a very useful concept for a variety of applications, the spontaneous emission in a SASE FEL can propagate statistical artifacts resulting from the inherent mathematical sum/difference phenomenon, and consequently can produce a beam exhibiting limited shot to shot reproducibility. As such, the utility of a SASE FEL might be limited in applications which require extremely accurate dosimetry. The limited shot to shot reproducibility might also contribute to the dosimetry phenomenon known as “shot noise”.

A Tunable HGHG FEL

FEL performance can be modified and improved by utilizing an external seed laser as a source wavelength. The seed laser is a conventional laser utilizing a material such as ruby crystal (one example) to produce a monochromatic feed source of photons. In an HGHG (High Gain Harmonic Generation) FEL, the seed laser interacts with the electron beam as it propagates through the first undulator (called a modulator), tuned to the seed laser's wavelength. The resulting interaction with the seed laser induces coherent modulation of the electron beam energy, creating photon bunching as well as consequential harmonic propagation (photons which are the mathematical multiples of the seed laser's wavelength). The micro-bunched beam of photons are then injected into a long undulator tuned to the desired harmonic wavelength. The desired wavelength comprised of harmonically produced photons arrive in phase and cumulatively intensify to release high energy coherent light at the newer, shorter wavelength of interest. A recent FERMI paper illustrates 500 shot reproducibility of 8th harmonic spectra at 32.5nm (obtained from a 260nm seed laser) exhibiting normalized photon/energy stability in the order of 7x10^-5 (root mean square), a marked improvement over previous SASE FEL data obtained over the same photon energy range. The high purity monochromatic spectra of an HGHG seed laser improves the system's shot to shot repeatability as its mode of operation does not incur the statistical deviation phenomena found in spontaneous emission spectra typically observed in a SASE FEL. As such, an HGHG FEL might be more advantageous for use in EUV applications requiring highly precise dosimetry, possibly reducing shot noise phenomenon. 

The EUV Source Challenge Ahead

Large scale projects are underway to build FEL systems to accommodate a wide range of wavelengths and scientific applications. FEL is next generation laser technology which is perhaps the best candidate to replace the LPP/EUV source designs currently offered by ASML.

Known for its work in actinic inspection at the 13.5 nm EUV wavelength, Lawrence Berkeley CXRO Lab [6] is also part of a DOE consortium currently working on LCLS-II (Linac Coherent Light Source-II) [7] at Lawrence Livermore and SLAC. Last June at the 2015 International Workshop on EUV Lithography in Maui, Aaron Tremaine of SLAC presented a comprehensive review of possible FEL designs that might be considered for EUV lithography and identified the consortium of DOE laboratories participating in the EUV FEL program. The Who's Who list of DOE participants includes SLAC, Lawrence Berkeley National Labs, Fermilab, Argonne National Lab, Cornell, UCLA, RadiaBeam, AES and Radiasoft. In order to appreciate the scale and capital intensity of this project it becomes necessary to review Aaron Tremaine's 2015 EUV Litho, Inc. Workshop presentation, LCLS-II and Free electron laser drivers for EUV Lithography [8]. The report describes FEL design considerations and recommends a “Straight Shooter” beamline configuration for semiconductor EUV lithography applications. The report addresses Erik R. Hosler's (GLOBALFOUNDRIES) 2015 SPIE publication, “Considerations for a free-electron laser based extreme-ultraviolet lithography program”, (Proc. of SPIE Vol. 9422, 94220D, 2015). The good news is that many new FEL programs are in progress [9] and the LCLS-II at SLAC might provide a viable, solution for HVM/EUV lithography. More recently, visible collaboration between GLOBALFOUNDRIES and SLAC has established the ground work for possible in-fab FEL source designs. The subsequent challenge for any future FEL/EUV initiative, is that once again the convergence of the semiconductor industry and our national laboratory community will be required to deliver future lithography source technology for EUV and beyond.

ASML has taken the lead in providing viable interim EUV technology permitting the characterization of materials, resists, masks and process precision required for future generation lithography. Double patterning techniques utilizing 193i lithography will continue to enable CDs =<10nm. We can also speculate how 13.5nm multiple patterning might enable future nodes and continued process development. In the interim, the current ASML LPP/EUV initiative has enabled the ground work our industry requires for future precision nanometer scale lithography.

Let's continue working together to secure next generation EUV and the preservation of Moore's Law.

During the course of researching this article I digested many components of the SLAC Conceptual Design Report for the LCLS-II (Linear Coherent Light Source).  Among many, two components of the LCLS-II are the SXR (Soft X-Ray) and HXR (Hard X-Ray) undulators and their respective beam lines.  It is with some amusement that my FCC designated amateur radio call sign is WA2HXR which I acquired in 1970. It should be noted that my amateur radio operations are restricted to applicable licensed amateur radio frequency spectra which excludes X-Ray wavelengths.  
CQ SLAC CQ SLAC CQ SLAC DE WA2HXR K.     73   

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Thomas D. Jay
Semiconductor Industry Consultant
Thomas.Dale.Jay@gmail.com
https://ThomasDaleJay.blogspot.com

Thomas D. Jay YouTube Channel

Visit my new Amateur Radio blog at:
www.WA2HXR.blogspot.com


















Corporate, private entities or publications referenced or linked in this article are the respective owners of their logos, trademarks, service marks, media content and intellectual property. Unless otherwise disclosed, Thomas D. Jay has no financial interest in companies referenced in blog articles or other published media communications. Thomas D. Jay is not a registered financial advisor. No representation is made to either buy or sell securities. Opinions expressed by Thomas D. Jay are his own. Thomas D. Jay does not employ or otherwise utilize/authorize third party agents to express his opinions, represent his interests or conduct business on his behalf except where formally contractually designated. Thomas D. Jay does not agree to indemnify or hold harmless vendors, clients or third parties to related contractual agreements and reserves the right to applicable legal remedies in lieu of arbitration. These terms are subject to change. Concerned parties should check this blog site for periodic updates.

Acknowledgments and Reference Links

[1] Free Electron Laser
Wikipedia

[2] Future FEL/EUV Strategy – The Light at the End of the Beam Line
Thomas D. Jay, Blog Publication, September 20, 2014

[3] ASML and Carl Zeiss acknowledged in an invited paper at SPIE Advanced Lithography 2015, that higher resolutions will require 60mJ/cm2 for half pitch nodes <8nm
SPIE Proceedings

[4] Extending extreme-UV lithography technology
SPIE News Room, Erik R. Hosler, Obert R. Wood II, Moshe E Preil

[5] The first solid state, 694nm synthetic ruby laser produced at Hughes Research in 1960
Wikipedia

[6] Lawrence Berkeley CXRO Lab
Lawrence Berkeley National Labs CXRO Web Site

[7] Linac Coherent Light Source-II
Stanford Linear Accelerator Web Site

[8] LCLS-II and Free electron laser drivers for EUV Lithography
Aaron Tremaine Presentation, SLAC
EUV Litho, Inc. Web Site, 2015 Program, Maui

[9] many new FEL programs are in progress
University of California, Santa Barbara FEL Web Site
Site Maintained by G. Ramian

The EUV Continuum - Have You Seen the Light?

It is August, 2014. Semicon West has long past and from an EUV perspective not much has changed. Another year, another conference series, and still no news to report on high power EUV product offerings other than another forward looking statement from ASML anticipating >100 watt EUV power levels at Semicon West next year. Recently developed EUV resists formulated at Lawrence Berkeley's CXRO have been a bright spot in recent developments.

It would seem the past ten years have been a repeating loop in which the on-going investment in EUV technology has yet to yield results commensurate with the engineering tours de force resident at ASML and the consortium of semiconductor manufacturers who have become its major stock holders. The last major engineering enhancement credited with increasing EUV source power was the fine tuning of a pre-pulse laser, providing a few additional watts but still short of required HVM power levels. How will EUV power output be optimized to required HVM power levels? At the moment, there are no clear answers. 

The multi-billion dollar semiconductor industry that has sustained Moore's Law continues to finance research and development over a multitude of technologies which will collectively enable 7 nanometer process technology and future picometer pursuits. It is a given that major players in the semiconductor equipment industry have deep pockets with which to market capital intensive technologies while quietly developing next generation products in a less than optimal economy.  Collectively the semiconductor manufacturers and the equipment industry exhibit massive economic momentum which occasionally slows to assimilate new markets and pre-position next generation technology products. This massive economic momentum also foments evolutionary technology championed by industry visionaries. Long term investors familiar with the semiconductor market segment have become adept at reading the strategies of key industry players, drawing confidence from past performances, and the solutions to seemingly unsolvable engineering challenges to Moore's Law. Although EUV technology has yet to yield HVM performance, the sheer momentum of the industry will sustain alternate technologies as interim solutions to the EUV dilemma. ASML has maintained its leadership in the lithography markets by optimizing current 193nm lithography with multiple patterning techniques, providing half pitch resolution with sufficient precision to accommodate challenging process nodes  =<10nm. As such, ASML will continue to enjoy leadership positioning in the 193nm markets while seeking engineering solutions which will ultimately enable higher power EUV. Directed self assembly techniques (DSA), and Nano-Imprint Lithography (NIL) continue to gain acceptance and process share as these technologies mature.

In observance of the ten year EUV odyssey, we should pause to reflect on the industry and its steadfast pursuit of EUV technology despite continual reported delays and setbacks in the program. Teams of Ph.D. researchers and engineers conduct a relentless effort to improve the performance of key manufacturing systems, continually upgrading the production, precision and metrology required to produce consumer products by mass assembly on an atomic scale.  EUV technology is recognized as a key enabler to lowering production costs by providing superior nanometer scale imaging and reducing the number of cost intensive mask levels for a given product. For the past ten years we have observed incremental progress in EUV and the infrastructure required to facilitate its HVM insertion.

Over the years, the cost of R&D associated with semiconductor process development and related lithography tooling has risen dramatically. Thus far, such cost barriers have been overcome by the efficiently pooled resources of the semiconductor industry and equipment suppliers, reducing costs by sharing resources and the associated expense burden. Historically, SEMATECH has lead many successful technology initiatives bringing complex R&D programs to operational status in the wafer fab. Other groups such as the G450C have teamed to provide the capital and engineering expertise required to meet the future 450mm HVM insertion time line.

If we find ourselves disappointed with current developmental efforts in EUV, what then might we consider newsworthy?  In a July 10, 2014, IBM press release, plans were announced for the company to invest $3B over the next five years on advanced semiconductor technologies.  Historically, IBM's R&D expenditures have averaged $6 Billion annually, spread over many disciplines. The commitment of an additional $3 Billion suggests a 10% increase in IBM's R&D program over the next five years. As IBM intends to make investments critical to future semiconductor device design (and by linkage required lithography techniques), is it possible that IBM will conduct its own initiative to further the development of EUV (Extreme Ultra Violet) light source technology?  High power EUV must be proven reliable to ensure the availability of future 13.5nm lithography HVM.  On July 25, 2014, I emailed the IBM media contact referenced in the news release, seeking clarification on IBM's $3 Billion budget increase announcement. My inquiry is currently unanswered, however on July 29, 2014, Dan Corliss, IBM's EUV Lead Technologist and Program Manager for Lithography R&D, announced a recent test in which their NXE:3300B stepper had been upgraded with a 44 watt EUV light source (as measured at the intermediate focus) and had produced 637 wafer exposures in “normal production mode”. No doubt, this announcement was intended to renew enthusiasm in the EUV program and highlight IBM's participation in an on-going industry wide effort.  However, the news quickly drew skepticism and later criticism when it was learned that the NXE:3300B's actual run rate was 34 wafers per hour, inclusive of two system “process interrupts” during the 24 hour test. Two industry analysts injected further criticism pointing out the EUV energy/dosimetry was insufficient for HVM and that blank wafers were used for the test, yielding no real data for viable analysis. Suggestions were made that the reports of the test results were misrepresented and that stock holders investing in EUV semiconductor lithography were possibly being mislead.

Let's step back for a moment and consider this latest IBM test in context with historic EUV light source development. Since the inception of the EUV program at the National Ignition Facility over ten years ago, EUV power levels (as measured at the intermediate focus of lithography tools) have yet to achieve sustained >150 watt power levels required for HVM (High Volume Manufacturing).  Although there have been reports of higher output power levels approximating 100 watts, these results represent peak power levels observed for brief periods which have not been sustainable during extended operational tests. More recent EUV source shipments from ASML have demonstrated EUV power levels of 25 watts with newer upgrades enabling 40 watt capabilities as recently reported by IBM. The ten year reporting history of the EUV program reflects the power limitations imposed by conventional physics and our struggle to rewrite the rules. We've modified the rules previously with man made additions to (and harvesting of) the periodic table proving hafnium is better than none. But, in the realm of semiconductor manufacturing, a fifty percent EUV power solution is unacceptable. The recent IBM test was part of a continuing effort to evaluate the incremental improvements made to EUV source technology and should not be interpreted as a failure.

In previous blog articles I've proposed solutions to resolving EUV power output limitations utilizing dual or multiple source designs. Multiple source designs utilized in previous EUV prototypes did not appear to accommodate multiple light source matching and optimal Etendue. Achieving efficient Etendue might appear challenging.  However, utilizing Bragg cell mirrors it's possible that two (or more) EUV light sources might be simultaneously focused and phased within a single stepper IF. That considered, the total system MTBF (Mean Time Between Failure) might still be problematic as both sources will generate contaminating tin particulates which coat mirrors and critical wafer target surface areas. This phenomenon resulting in source/system/mirror contamination might be the limiting factor in Sn (tin) based LPP (Laser Produced Plasma) source technology.

To date, no one I've spoken with has an acceptable answer for how EUV power might be scaled to required HVM levels given current ASML LPP source designs. I'm sure we'd all be pleased to see ASML wheel a secret, high power EUV/HVM prototype onto the test lab floor, but over the past ten years many in the industry have become quite skeptical.

The larger question remains, why has the EUV program stalled and when will a technology break through occur? Over the years we have seen many semiconductor manufacturers and equipment vendors independently own and operate R&D programs. While there is great economy of scale in the collective funding of R&D by the large consortiums and foundry alliances, the investment in a singular technology as determined by committee vote can displace the valuable pursuit of multiple design concepts, effectively reducing opportunities for new scientific discovery and timely delivery of process solutions.

Given the newly announced R&D initiative by IBM, I will site an example worth revisiting.  During the late 1970's, semiconductor manufacturers recognized that greater control was required in diffusion tube processing utilizing dopant gases. It was realized that more precise control of dosimetry was required and a next generation process solution was considered. IBM released a request for quotation (RFQ) to equipment vendors for a high current ion implanter capable of ionizing dopant gases (typically boron, phosphorus and arsenic) and implanting the high energy ions directly in wafer substrates.  As there were no manufacturers of high current ion implanters at the time, no one bid on the IBM request. Given a no bid response, IBM engineers designed and built their own high current ion implantation system they called the Tachonic series (named after the surrounding Tachonic mountain range formations). Using off the shelf commercial parts where possible, a highly skilled IBM engineering group assembled (at great expense) a high current ion implantation system featuring mechanical beam scanning and precise dosimetry control. Several of the systems were built and were later retired when commercially manufactured systems became available. During the Tachonic series service lifetime, IBM experimented and mastered the mitigation of CMOS wafer surface charging with electron flood guns. Interestingly, AT&T Technologies and General Electric also produced their own similar (but different) high current ion implanters utilizing mechanical beam scanning techniques. There were no consortiums funding any singular concept for high current ion implantation hardware, and innovative designs soon gave birth to a high current implant industry. IBM's July 10, 2014 press release celebrates the many contributions it has made to the semiconductor manufacturing industry inclusive of process control, wafer fabrication technique and specialty tooling required for HVM. Could it be that the consortium of Intel, TSMC and Samsung funding EUV development at ASML has unintentionally displaced competitive R&D?  By accident or design, this is what has happened.

How might we shift gears and accelerate EUV development? The current EUV LPP program got its historic start when the Extreme Ultraviolet LLC (Intel, Motorola, Advanced Micro Devices and Micron Technology) contracted the DOE/Lawrence Livermore Labs to develop an LPP EUV source for the semiconductor industry. The decision was made that EUV was to be a laser based technology and consequently the EUV program evolved into the LPP platform currently marketed by ASML.

Early in my career I had the opportunity to visit Princeton Plasma Physics Laboratory and examine one of the first Tokamak fusion reactors there. The concern at the time was the inside surface wall of the reactor might be damaged by an unstable high temperature plasma. In later experiments at Princeton and fusion laboratories around the world, it was confirmed that turbulent plasma could be controlled using sheared flow techniques, reducing the potentially destructive effects of plasma contacting the chamber wall.

An innovative EUV source design introduced by a US based company called Zplasma utilizes z-pinch technology employing a patented sheared flow stabilization technique to produce both stable plasma pulse formation and 13.5nm EUV light emission.  Given the current LPP/EUV source design supplied by ASML/Cymer has yet to achieve HVM power levels, the EUV LLC consortium might want to pursue a similar EUV source development contract with Zplasma or a national laboratory experienced with z-pinch plasma technologies designed to optimize EUV output.  We must infuse new competitive thinking with competitive actions if we are to achieve a break through in EUV source power.  Hopefully IBM will contribute additional expertise to the EUV program given its increased R&D funding.  New inspiration and initiatives are needed to rekindle the diverse sources of innovation the semiconductor industry is known for.  

In the scheme of things we must consider how far we've advanced today's semiconductor technology.  Physicists at CERN in Switzerland operate a particle accelerator called the Large Hadron Collider. There on March 14, 2013 the existence of the theorized Higgs Boson was tentatively confirmed to have a mass of 125 GeV. The Higgs Boson is thought to impart the qualities of mass in matter and is sometimes referred to as “the God particle”. The search for the Higgs spanned 40 years and concluded after the construction of the Large Hadron Collider, costing an estimated $4.4 Billion (with a $9 Billion operational budget). By 2015 it is anticipated the acceleration energy at the LHC will reach 7 TeV, enabling particle collisions at 14 TeV. It seems ironic that on one hand physicists at CERN are utilizing high energy physics to smash and examine the components of sub-atomic structures, while semiconductor engineers implant ions at energies up to 2 MeV, purposefully creating sub-atomic lattice structures in flash memory cells. While we might debate “the God particle” reference ascribed to the Higgs Boson, the sound of Seri speaking from an iPhone must invoke a religious experience for her futurist creators.  It seems we're in a new line of business.

Please join me in supporting the National Photonics Initiative, SPIE and the International Year of Light 2015.

Thomas D. Jay 

Semiconductor Industry Consultant

Thomas.Dale.Jay@gmail.com

www.ThomasDaleJay.com

Thomas D. Jay YouTube Channel

 
 

Corporate, private entities or publications referenced or linked in this article are the respective owners of their logos, trademarks, service marks, media content and intellectual property.  Unless otherwise disclosed, Thomas D. Jay has no financial interest in companies referenced in blog articles or other published media communications. No representation is made to either buy or sell securities. Opinions expressed by Thomas D. Jay are his own. Thomas D. Jay does not employ or otherwise utilize/authorize third party agents to express his opinions, represent his interests or conduct business on his behalf except where formally contractually designated.

Acknowledgements and Reference Links

ASML

Lawrence Berkeley CXRO

SEMATECH

G450C

IBM Press Release

National Ignition Facility

Princeton Plasma Physics Laboratory

Zplasma

CERN (Wikipedia)

Large Hadron Collider (Wikipedia)

National Photonics Initiative

SPIE

The International Year of Light 2015


Related blog articles of interest
by Thomas D. Jay

June 2014
Semiconductor Industry Markets in the Economic Hay Stack

March 2014
A Perspective on EUV Lithography Feb. 2014
The NIF Shot Heard Around the World

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August 2013

The Continuing Evolution of Extreme Ultra Violet Lithography 

May 2013

The Strategic Positioning of Electron Beam Lithography

April 2013

Direct Write E-beam Lithography; Complementary Technology in the Fab 

March 2013

Report on Recent SPIE Activities - Spring 2013

February 2013
Zplasma to Attend SPIE Advanced Lithography 2013 Seeking Xenon Z-pinch EUV Source Funding

February 2013
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 January 2013

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January 2013

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January 2013

IBM - High Tech R&D Powerhouse

A Perspective on EUV Lithography Feb. 2014 The NIF Shot Heard Around the World

Opening commentary by Thomas D. Jay on YouTube

SPIE Advanced Lithography V 2014 provided no encouraging news on further development of EUV power output for advanced semiconductor HVM. During the week of the conference it was announced that a recently shipped ASML NXE:3300B [A] stepper/scanner with a 30 Watt EUV source failed during its trial run at TSMC. Accidents happen. Over the years I have witnessed several spectacular meltdowns of high energy/high value wafer fab equipment. Recovery is rapid as wafer fab crash teams resolve such incidents in short order. 

The quest for higher power EUV has been a greater challenge than originally anticipated. Unfortunately this latest occurrence at TSMC punctuated a ten year continuance of forward looking statements in which ASML/Cymer repeatedly anticipated imminent arrival of EUV power levels of 100 watts or more.

The Ultimate Shot Noise

Interestingly, the search for advanced, future semiconductor EUV lithography technique has been an on-going effort that began many years ago. In 1994 the National Ignition Facility (NIF) at Lawrence Livermore National Laboratory began the Laser Science and Technology (LS&T) Program [1] whose research would chart the course for many future advanced technology projects. The National Ignition Facility  [1A] team is to be congratulated on their most recent August 13, 2013 experiment which produced output power greater than that of input levels. The NIF utilizes 192 individual high energy lasers focused on a small deuterium target with the goal of emulating the physics of our sun and unleashing large amounts of fusion energy.

See Wikipedia NIF photos:

[A] NIF main building schematic. 

[B] NIF laser preamplifers. 

[C] NIF laser bay (there are two such laser bays, 300 yards long producing 500 Terawatt pulses of energy with 192 high power lasers.  

[D] NIF target chamber (30 feet in diameter). 

[E] Target chamber view port. 

[F] NIF target chamber exterior.

[G] NIF laser flash lamps. 

AMP

A subset of the Laser Science and Technology program was AMP, the Advanced Microtechnology Program, providing research and development resources in semiconductor imaging and detection. AMP was considered a show case example of the U.S. Department of Energy's (DOE) efforts to transfer and commercialize newly developed technologies to U.S. commercial interests. The semiconductor industry now had the attention of world experts in plasma and light source technology.
 

The Birth of Laser Produced Plasma EUV 

The NIF began work on Laser Produced Plasma EUV. Plasma produced from Sn (tin) or Xe (xenon) enables the creation of a 13.5nm EUV light source, an item of key interest to next generation lithographers in the semiconductor industry. The NIF built a 13.5nm Laser Produced Plasma (LPP) test stand which successfully provided this desired wavelength of vacuum EUV. AMP and its associated EUV research and development would become LS&T's largest program. 

Later, three DOE laboratories; Lawrence Livermore, Lawrence Berkeley, and Sandia Laboratories in California went on to form the Virtual National Laboratory (VNL) to further research and develop extreme ultraviolet lithography (EUVL) technology. The VNL was funded by the Extreme Ultraviolet LLC, a consortium of Intel, Motorola, Advanced Micro Devices, and Micron Technology. Semiconductor industry heavy weights were now interacting commercially with the formidable technology base of the U.S. Department of Energy. The three year, $250 million venture was dedicated to developing EUVL for commercial manufacturing of computer chips and to foster migration of the technology to semiconductor production facilities by 2010. Each national laboratory contributed expertise to this effort; Lawrence Livermore (optics, precision engineering, and multilayer coatings), Sandia Labs (systems engineering, photoresists, and light source). Berkeley contributed its Advanced Light Source capability, generating EUV light to characterize optics and resists at the nanometer scale. SEMATECH now similarly sponsors and benefits from the development of actinic EUV metrology at the Lawrence Berkeley Center for X-ray Optics (CXRO). 

A Fifteen Year Chronology of EUV

Source Development 

- On May 6, 1998 Arthur W. Zafiropoulo, Chairman, CEO and president of Ultratech, formed United States Advanced Lithography LLC, and reached an agreement with EUV LLC (the consortium of Intel, Motorola, Advanced Micro Devices, and Micron Technology) in order to further develop and transfer EUV technology to American lithography manufacturers. Zafiropoulo wanted to ensure U.S. semiconductor equipment vendors remained competitive in the world economy by producing EUV lithography tools on American soil. [1B]

- On June 24, 1999 ASML of the Netherlands reached an agreement with EUV LLC, (the consortium of Intel, Motorola, Advanced Micro Devices, and Micron Technology) to participate in the further development and transfer of EUV technology to semiconductor lithography manufacturers. By participating in the EUV program facilitated by EUV LLC, ASML became a defacto beneficiary of the EUV research conducted by the U.S. DOE. Martin van den Brink, executive vice president of marketing and technology at ASML was later quoted as saying “While EUV is expected to have the highest throughput and most extendable resolution, the complexity of non-optical techniques requires the parallel evaluation of multiple options."  ASML moved rapidly to secure its position in the future lithography market place.

- In June, 2006 Cymer put its first LPP EUV source into operation.

- In November 2007 Cymer reported achieving 100 watts of EUV burst power on its LPP source. [2]

- On May 14, 2008, Cymer reported the achievement of continuous EUV source operation for over one hour at an average power level of 25 watts. [3]

- In July 2009 Cymer announced the shipment of an LPP source to ASML, claiming it had achieved 75 watts of “EUV exposure power” and anticipated 100 watt power levels within 90 days enabling 60 wafer/hour throughput on 300mm wafers. [4] 

- In 2010 Cymer reported achieving 100 watts of EUV peak power for brief periods but was only able to provide 10 watts of continuous EUV output. ASML began evaluating three potential suppliers of EUV sources; Cymer, Gigaphoton and Extreme Technologies. [5]

- In July 2011, at a company earnings conference call Bob Akins, then Cymer's Chairman and CEO reported “As a result of increased source availability and stability improvements, the eight (EUV) sources have cumulatively produced greater than 40 megajoules of EUV since March of this year and it is sufficient to expose greater than 3,000 wafers”. [6]

- In February 2012, Cymer reported shipping three 8 Watt EUV sources but 20 watt upgrade shipments for NXE-3100 systems were delayed. [7]

- In May 2013, Cymer's EUV source power output was still short of HVM targets. ASML completed the Acquisition of Cymer in a cash and stock transaction estimated to be $3.7 Billion. [8]

- As reported on February 24, 2014 during SPIE Advanced Lithography V, an NXE:3300B, was shipped to TSMC with an integrated 30 Watt EUV source from ASML/Cymer, failed during testing but was later repaired. [9]

A Perspective on Extreme Ultra Violet Lithography 
March 11, 2014  

In 2008 Arthur W. Zafiropoulo, Chairman, CEO and President of Ultratech, estimated that EUV lithography systems could be premium priced as high as $15 to 20 million each, affording a significant market opportunity. The interplay of the NIF and EUV programs promulgating the current lithography initiative has exposed two starkly differing cost center/ROI models. The National Ignition Facility took tewlve years to build and houses 192 high power laser bays 300 yards long, producing 500 Terawatt laser “shots” (500 Trillion watts) focused on a single deuterium pellet with the goal of replicating the fusion energy created in the core of our sun. Funded by the U.S. Government's Department of Energy, the NIF facility cost $3.5 Billion to construct. Given current ASML pricing at $120 Million each, a quantity of 25 ASML EUV stepper/scanners, each anticipated to produce 150 watts of front end LPP EUV illumination, are now estimated to cost $3 Billion. If we utilize Mr. Zafiropoulo's original high end estimate of $20 Million per stepper, the cost for the same 25 EUV steppers is reduced to $500 Million (the number to the right of the decimal point on the NIF's construction cost). The collective investments in ASML made thus far by Intel, Samsung and TSMC actually exceed the NIF's $3.5 Billion construction cost. Is an ASML equipped semiconductor front end EUV lithography fab (25 EUV steppers) really at cost parity with a U.S. government sponsored fusion energy project?  Given current wafer fab construction costs approximating $5 to 6 Billion, ASML's recently quoted EUV lithography pricing is unprecedented.  This singular discrepancy in the semiconductor industry's cost continuum has displaced Moore's Law as a viable operand.  EUV technology originally developed within the U.S. DOE/NIF program has been transferred to cooperative multinational interests outside any U.S. based cost control infrastructure.  Electron beam lithography as an alternate HVM solution was never funded on a large scale leaving ASML as a defacto sole source for nanometer scale HVM. This is why the EUV program is on hold. It's time to call the accountants, get costs under control, and restore U.S. based best of breed lithography competition to the semiconductor industry.  We all applaud the efforts of our friends at ASML who have made extraordinary strides in the development of EUV.  However, with ASML as the primary beneficiary of the NIF's EUV Laser Produced Plasma program, the U.S. based semiconductor equipment industry should be competing with them for both economic and strategic considerations.
 
The current and on going status of EUV endures as a great drama for those of us with keen interest in the semiconductor industry and the phenomenon of Moore's Law. Although ASML stock holders should continue to benefit from their dominate front end market share, it would appear ASML's customer/investors are getting less return on their subsidy of EUV as progress on HVM power output development has stalled. Although there are few remaining EUV players (none with ASML's front end market share), the current economic complexity of the EUV program compounded by the throttling of the 450mm initiative has quashed enthusiasm for large scale investment in new, competitive EUV and alternative lithography technologies targeting CDs <28nm. The current over capacity status at many fabs has also delayed further investment in tweaking strategic product positioning, best illustrated by Intel's idling of newly constructed fab 42. 

With regard to next generation semiconductor products, we might choose to continue optimizing cloud based CPUs and servers as another way of offsetting increasingly heavy processing demands until nanometer scaling enabled by restoration of the EUV initiative or SEMATECH's alternate choice, electron beam lithography enables us to re-institute the spirit of Moore's Law.

Please join me in supporting the National Photonics Initiative, SPIE and the United Nations proclaimed International Year of Light 2015.

Thomas D. Jay 
Semiconductor Industry Consultant
Thomas.Dale.Jay@gmail.com
www.ThomasDaleJay.com
Thomas D. Jay YouTube Channel
 
 


 
 


































Corporate or private entities mentioned in this article are the respective owners of their logos, trademarks, service marks and intellectual property. Unless otherwise disclosed, Thomas D. Jay has no financial interest in companies referenced in blog articles or other published media communications. No representation is made to either buy or sell securities. Opinions expressed by Thomas D. Jay are his own. Thomas D. Jay does not employ or otherwise utilize/authorize third party agents to express his opinions, represent his interests or conduct business on his behalf except where formally contractually designated.

Acknowledgements and Reference Links

 SPIE.org

 Photonics for a Better World.blogspot.com

National Photonics Initiative

 [A] ASML NXE:3300B, ASML Web Site

[A1] Ultratech

[1] Extreme Ultra Violet Lithography, Imaging the Future

[A-G] NIF Photos, Wikipedia 

[1A] National Ignition Facility, Lawrence Livermore National Laboratory  

[1B] May 6, 1998 Business Wire

[2] November 30, 2007 Business Wire 

[3] May 14, 2008 FABTECH

[4] EE Times July 13, 2009 

[5] August 19, 2011 Engineering and Technology Magazine, by Chris Edwards

[6] July 21, 2011, Morning Star 

[7] February 3, 2012 Semiconductor Engineering, by Mark LaPedus

[8] May 30 2013 UT San Diego, by Mike Freeman

[9] February 24, 2014 Semiconductor Engineering, by Mark LaPedus

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The Strategic Positioning of Electron Beam Lithography

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Direct Write E-beam Lithography; Complementary Technology in the Fab 

March 2013

Report on Recent SPIE Activities - Spring 2013

February 2013

The 13.5 Nanometer Physical Cliff? 








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