Thomas D. Jay

Tuesday, April 16, 2013

A New Volunteer at University of Central Florida's Mentor Network for Entrepreneurs

As per recent invitation from the University of Central Florida I am participating as a volunteer mentor in UCF's Mentor Network for Entrepreneurs. This group assists CEO's and management from business incubators and start ups by providing broad based expertise in business development inclusive of strategic sales marketing initiatives. Thank you UCF and special thanks to Robin Phelps at UCF's office of Research and Commercialization. I look forward to working with you and the team at UCF.

Best regards,

Thomas D. Jay
Semiconductor Industry Consultant
Thomas.Dale.Jay@gmail.com
www.linkedin.com/pub/thomas-d-jay/26/aa3/499
ThomasDaleJay.blogspot.com

Wednesday, April 10, 2013

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

On April 7, 2013 Yehiel Gotkis commented on my recent March 20, report on SPIE Activities (scroll down to my prior post) which spoke to developments in EUV lithography and related process issues. Yehiel questioned why my comments did not include discussion of Direct Write E-beam Lithography. Burn Lin of TSMC recently presented a status update on DWEB lithography at SPIE Advanced Lithography IV which prompts further discussion of this complementary lithographic technology. My response to Yehiel's comments follow:

Thank you for your observations on e-beam lithography. In my opinion direct write e-beam technology continues to demonstrate its value as an important component in the mix of lithography strategies used in both current and future semiconductor production. In addition to my recent blog comments on EUV, I made a brief reference to direct imprint, multiple e-beam and Directed Self Assembly (DSA) as supplemental alternatives to EUV lithography. My omission of commentary on e-beam technology was not intended to minimize its importance or viability in the semiconductor manufacturing market place. If there is limited success with the further increase of EUV source output power the extended dose/exposure times will enhance the competitive viability of e-beam lithography for HVM (High Volume Manufacturing).

As the semiconductor market evolves there will be niche markets for application specific lithography technologies which are best able to address process problems unique to newly emerging segments of the semiconductor industry. Currently, industry interest is focused on resolving EUV lithography HVM issues as evidenced by recent investments in ASML by Intel, TSMC and Samsung. Is direct write e-beam an HVM alternative to EUV or 193 nm lithography? For High Volume Manufacturing of RAM memory, many MPUs and other high volume commodity products the answer is probably no, not at this time, but events change quickly. This observation in no way disqualifies e-beam from other market segments where it has real value. In the 1980s IBM had a production line called QTAT (I'm sure the QTAT example has been cited many times). This was a Quick Turn Around Time direct write e-beam production line which supplemented the traditional optical lithography line. As explained to me by IBM years ago, one of the intended purposes of QTAT was to enable the IBM sales and marketing team to respond quickly to customer orders which were time sensitive. Traditional sales activity hand off to the wafer fab involves the strategic scheduling of fab assets to accommodate work flow determined by the mix of products in the factory. Often times this scenario represented multiple customers with specific, time sensitive delivery requirements. In most cases this work flow was efficiently scheduled on the optical lithography line where production costs were minimized. However, on occasion the fab would receive a time sensitive order which could not be easily integrated into the mix scheduled for optical production. These orders were sometimes routed through QTAT. In addition to the many standard photo mask sets in place at the IBM wafer fab, much of the product line was also replicated on the direct write e-beam system computers. When there was a resource conflict for use of the optical lithography line, the work flow could be diverted to the e-beam line. It was a simple matter to down load the e-beam lithography patterns with out concern for the time consuming loading and qualifying mask sets. It's probable that in most situations this was more cost and time efficient than work flow disruption of the optical line or loosing time sensitive orders to competition.

In today's foundry environment, direct write e-beam can provide a similar quick turn around back up capability on the production line. In addition to the significant evolution of e-beam lithography capabilities over the years recent renewed interest in complementary lithography support might also be reflective of the historic value of the QTAT concept. The ability to develop new products without concern for mask design/fabrication and optical lithography hardware can be very influential as the cost of nanometer scale production escalates.

It is rumored that direct imprint lithography systems are currently in use at a major flash memory manufacturer where complex, high cost products are being produced. In the absence of HVM EUV and given the added costs and complexities of 193 nm double patterning, direct imprint lithography can also become a contender for many niche applications.

Next generation nanometer scale lithography technology continues to evolve. Mapper, KLA-Tencor, JEOL, Multibeam,
PARAM, and Vistec are all engaged in research which pushes the envelope in both development labs and production fabs. Many industry actions and decisions will be keyed upon successful scaling of EUV power output, mask and resist issues. With regard to e-beam direct write systems, it's interesting to note that the full complement of current MEMS technology is being leveraged to create the electrostatic lens systems that enable some multiple e-beam lithography systems with their precision. A technology shake out is in progress.

Direct write e-beam lithography has its own set of advantages and technology node issues worthy of further discussion. I plan to report on e-beam lithography more expansively in the coming weeks.

Thomas D. Jay
Semiconductor Industry Consultant
Thomas.Dale.Jay@gmail.com
www.linkedin.com/pub/thomas-d-jay/26/aa3/499
ThomasDalejay.blogspot.com
The Technology High Ground

Wednesday, March 20, 2013

Report on Recent SPIE Activities – Spring 2013

Commentary on SPIE Advanced Lithography IV 2013

SPIE Advanced Lithography IV concluded February 28, a few weeks ago. I did not attend the conference this year but was in frequent contact with colleagues who were on the scene. I was able to obtain some interesting perspective (albeit remotely) on EUV events thanks to first person accounts, daily news and video updates on the SPIE web site and from other SEMI industry news media. My instinct to publish blog commentary immediately after the SPIE conference proceedings was throttled by additional background research in which I rediscovered recent, relevant historic data preceding and supplementing this years SPIE Advanced Lithography event.

ASML made a compelling fifty page presentation at SPIE which outlined their progress in sustaining the evolution of nanometer scale lithography while simultaneously supporting high volume manufacturing (HVM). The report outlined the status of ASML's current EUV lithography program demonstrating measured incremental progress in EUV power output but underscored its ability to deliver the precision and accuracy necessary for evolving nanometer scale lithography. Additionally, supportive data reinforced ASML's ability to implement complementary 193nm double patterned strategies as part of its EUV transition program. Tool to tool accuracy and precision data were presented, ensuring the availability of interim process solution sets concurrent with the evolution of EUV development. The EUV source power question was deferred to the continuing research and development effort at Cymer where gains have been progressing incrementally.

Following SPIE on March 12, at a recent UBS technology conference in Europe (Source: Seeking Alpha.com), ASML was asked if the Cymer supplied EUV light source was the only available option for its EUV lithography system. The ASML response was that they had designed a standard light source interface to the stepper but welcomed customers to optionally supply their own production proven EUV light source. Realistically, other than a few EUV source/systems under evaluation at imec, customers currently have few options and are probably best served by an ASML/Cymer source with an attached performance guarantee.

The SPIE conference again reminded us that the most pressing EUV lithography issues continue to be EUV laser/plasma based source technology, mask fabrication, resist performance and particle contamination concerns prompting a pellicle solution. The complex interaction of these critical issues create a matrix of challenges. The EUV resist component of this matrix was first comprehensively addressed in a 2011 paper: Stochastic Exposure Kinetics of Extreme Ultraviolet Photoresists: Simulation Study, by Chris A. Mack, James W. Thackeray, John J. Biafore and Mark D. Smith. You might think a paper from 2011 is old news, however, in my opinion it is perhaps the best summary of critical EUV resist issues and remains a valuable work of reference applicable to current EUV process concerns. Utilizing data derived from then available EUV resist materials a statistical analysis was performed to characterize lithography performance providing recommendations on possible process enhancing resist modifications. The paper summarizes seven parameters which could be optimized to improve EUV resist performance (itemized below). For complex structures and contact holes with dose exposure/shot noise sensitivity, the paper proposes that modification of resist chemistry and subsequent performance can be enhanced by:

Increase resist absorption of EUV light.

Reduce the electron affinity of the matrix polymer (reduce electron energy loss that does not result In PAG (Photo Acid Generator) excitation, thus increasing de and C)

Increase the electron affinity (and thus the reaction cross-section) of the PAG.

Minimize electron blur by increasing resist atomic density (thus reducing re).

Minimize acid diffusivity by using lower activation energy leaving groups and reduced post exposure bake temperatures

Reduce the spatial distribution fluctuations of PAG in the resist.

Reduce resist sensitivity to out-of-band radiation.

Fast forward two years to SPIE Advanced Lithography 2013. A few minutes after reading this 2011 paper I discovered James Thackeray's recent You Tube video posted on 2/25/2013 describing how Dow Chemical's recent improvements in EUV resist compounds effectively addressed the issues described in the paper of two years ago. You might ask, why does it take two years to resolve a photoresist design problem? The chemistries themselves are complex and comprised of nanoscale molecular components which must react selectively to 13.5nm EUV at 14X below typical exposure levels while maintaining integrity under high vacuum conditions with minimal outgassing. The search for materials exhibiting these extraordinary physical and performance characteristics is time consuming and requires an exhaustive R&D program. It's gratifying to observe that those who have effectively identified and communicated a complex problem set are also contributing the solutions.

Chris A. Mack's 2012 SPIE invited paper Line Edge Roughness and the Ultimate Limits of Lithography resets the EUV resist issue yet again. The recent encouraging news from James Thackeray and Dow Chemical might satisfy interim goals in the pursuit of shrinking nanometer scale geometries but the effort to further scale process technology is never ending (we think). Chris Mack's recent paper speaks to the continuing struggle with LER. After thoughtful dissertation on process parameters effecting LER he again suggests ways in which EUV resists might be further improved. EUV exposure/dose is another parameter which can improve LER if only more power were available to provide viable exposure times demanded by HVM throughput requirements. An anemic EUV photon count contributes to LER, poor contact hole resolution, shot noise, reduction in throughput and the gamut of related effects. James Thackeray's recent You Tube video employs a popular illustration utilized to depict this problem. Two adjacent plasma chambers exhibit marked differences in photon density with EUV depicted as 14X less. Dr. Thackeray comments that with 14X less “information” EUV dosage at desired levels remains a challenge. As an FCC licensed amateur radio operator, I'll site my own analogy. Ham operators communicate using radio, mostly by voice but also transmit encoded “information” employing radio teletype, slow and fast scan television. We sometimes talk to the astronauts on the International Space Station on a special link. As a gentleman's hobby, the rule is to use minimal power necessary to maintain communications so as not to interfere with other stations or adjacent radio services. On occasion, path loss between stations, atmospheric conditions and noise levels mandate adjustment to this guide line. One thousand five hundred watts of effectively radiated peak envelope power usually delivers sufficient RF signal strength to “burn a path” to the receiving station. Signal to noise problems are mitigated and the message gets through. It's time for Cymer to crank up the output power.

Although there have been many positive developments reported at this years SPIE Advanced Lithography conference, many of the same critical EUV lithography issues remain on the agenda. Some items have been resolved only to be replaced by newer design and performance challenges. The engineering funnel feeding Moore's Law flexes to accommodate bumps in the road map as the physical limits of materials and energy science are pressed ever further. Forward looking HVM road maps project that performance improvements in resist LER (Line Edge Roughness), EUV power output and shot noise will eventually converge to resolve the HVM (High Volume Manufacturing) yield and throughput issues given time. With continued investment, EUV nanometer scale lithography HVM could well emerge to sustain Moore's Law. In the interim, parallel research continues in e-beam and direct imprint lithography as well as DSA (Directed Self Assembly) techniques for patterning nanoscale device structures. ReRAM technology has recently been adapted for key next generation products which are candidates for these alternate manufacturing techniques.

Lawrence Berkeley National Labs CXRO Update
Later this year 2013, the enhanced performance SHARP (SEMATECH High-NA Actinic Reticle review Project) is scheduled to go on line. The effort will be led by Kenneth Goldberg, Ph. D. at Lawrence Berkeley National Labs CXRO (Center for X-Ray Optics). The enhanced EUV microscope/inspection station with 0.5 NA will be available for SEMATECH members conducting EUV lithography research. The system has undergone many hardware upgrades and performance enhancements and should prove extremely valuable in the continuing EUV process development agenda. Patrick Naulleau, Ph.D. is the Director of LBNL CXRO and chaired this years SPIE Advanced Lithography IV program, providing unique insight on the industry wide EUV initiative.

SPIE at Optics and Photonics: Lighting a Path to the Future
In addition to SPIE Advanced Lithography, another important SPIE co-sponsored initiative took place on February 28, in Washington, DC, titled, “Optics and Photonics: Lighting a Path to the Future.” Other organizations co-sponsoring the event included the IEEE Photonics Society, Optical Society (OSA), American Physical Society, and the Laser Institute of America. The event was attended by many government agencies who traditionally sponsor research. The goal of the conference was to foster better government collaboration with American optics and photonics industries and forge a National Photonics Initiative (NPI). The value of this proposed initiative is best exemplified by recent semiconductor industry manufacturers' investments in ASML and Cymer. The collaboration of industry and government in key photonic and optical science endeavors could dramatically distribute R&D expenditures and reduce costs across many disciplines.

SPIE at CREOL Industrial Affiliates Symposium
On March 8, SPIE members also participated in The CREOL Industrial Affiliates Symposium (College of Optics and Photonics at the University of Central Florida) held each spring (currently numbering 70 members). Themed “Light in Action” the event was also attended by Dr. Eugene Arthurs and Steve Anderson of SPIE. The following day Dr. MJ and Cheryl Soileau hosted the annual CREOL “Spring Thing” event, an annual Cajun cuisine cook out at their residence on Lake Jesup. Dr. MJ Soileau is the current Vice President of Research and Commercialization at UCF. Having attended the “Spring Thing” event at MJ's in the past, (unfortunately not this year) I can vouch for its Cajun authenticity. “MJ” goes into rare form, rolls up his sleeves and stirs up a pot of spicy vittles which is always a delectable crowd pleaser. Unknown to most, MJ also keeps a secret supply of his world famous hot sauce in his desk at UCF. Those seeking inspiration are encouraged to sample this formula known only to MJ. I once advised him on its stored energy potential commenting that “While not exactly fusion in a bottle, I suspected Pons and Fleischmann would be proud.” Thanks MJ for your inspiration and all you do for UCF.

Zplasma Update
My blog entry last month featured an Interview with Henry Berg, CEO of Zplasma who is currently seeking funding for further development of a Xenon based Z-pinch EUV source. During the SPIE Advanced Lithography conference there was interest in Zplasma EUV technology but no immediate success in securing funding. Feedback from my recent interview with Henry provides insight he gathered from the conference while providing perspective on possible future opportunities for Zplasma.

Henry Berg – CEO, Zplasma:
“It was very exciting to bring Zplasma’s SFS technology to SPIE and talk to companies that will benefit from our Stable DPP source. We are addressing the four key areas where previous DPP sources ran into difficulties:

Electrode Melting: Previous DPP sources used a short, unstable pinch that required high instantaneous power levels that raised electrode surface temperatures above the melting point of tungsten (3695 K). Zplasma’s SFS pulses are 10-100 times longer, so the required instantaneous power levels are 10 times lower, which keeps electrode surface temperatures below the melting point.

Electrode Pitting and Erosion: The unstable plasma used in previous DPP sources was subject to current interruptions caused by plasma instabilities. The current interruptions caused high voltage spikes that ripped charge carriers out of the electrodes, causing pitting and erosion. Zplasma SFS stable plasma eliminates the voltage spikes that were the root cause of the pitting and erosion.

Etendue Match and Collectible EUV Light: Poor etendue match and the use of grazing incidence collectors meant that previous DPP sources could not collect enough light. SFS emission volume is adjustable for a high etendue match, and SFS geometry supports side-on collection with an ellipsoidal multilayer mirror, so the Zplasma Stable DPP source can deliver high EUV power levels to the stepper IF.

Dose Uniformity: Previous DPP sources had unpredictable plasma instabilities, which made controlling dose uniformity difficult. SFS stable plasma allows for EUV emission under control of the power supply to provide dose uniformity control better than the industry target of 0.2% 3-sigma deviation over 50 pulses.

We had some great discussions about the advantages of Zplasma’s source, with particular interest in the simplicity of Stable DPP and the resulting increase in reliability and reduction in cost of ownership. We are talking to several companies now about supporting the development of our source. We are also exploring several new secondary applications as a result of meetings at SPIE.”

SPIE Advanced Lithography IV 2013 provided a wealth of information and insight on the current status of EUV lithography and has also set the stage for the continuing development of required complementary technologies. KLA-Tencor introduced its Spectra Shape 9000 laser/plasma based inspection station and is said to be developing an EUV actinic inspection tool. As the complexity and sophistication of these instruments increase, so does the cost to manufacturing. The result is further stratification of the semiconductor equipment industry and the likely continued expansion of the foundry business model. Interestingly the business models for most of these scenarios are sometimes analyzed on iPhones, but look out Apple, the Samsung S4 will arrive next month. Competition is a wonderful thing. But then we all know that.

For those interested in my ham radio comments: Yes hams really can talk to the astronauts on the International Space Station. Most of the astronauts are also licensed hams with their own call signs. The astronauts have a very busy schedule and operate the ISS ham station in their spare time which is not very often (usually after their dinner). To contact the ISS it must be overhead for direct path VHF/UHF communications. Visit the NASA link for ISS ham radio frequencies and transmission modes and the American Radio Relay League for more information on Amateur Radio: http://spaceflight.nasa.gov/station/reference/radio/
www.arrl.org

Ham Radio Update 3/28/2013. Two Hams are scheduled to arrive at the ISS. NASA TV will televise coverage of vehicle docking with the ISS at 10:30 PM EST Thursday evening 3/28. Check the ARRL link below for more information on the astronauts. http://www.arrl.org/news/two-hams-scheduled-to-head-to-iss-this-week

As semiconductor equipment manufacturers expend considerable funding to create exotic plasma systems, the ISS crew is sailing above a sea of plasma easily viewed from their moving vantage point. I suggest you visit the NASA link below for an incredible view of our planet:

Plasma display courtesy of NASA and the ISS:http://www.youtube.com/watch?v=hWz5ltE_I4c&feature=player_embedded

Thomas D. Jay
Semiconductor Industry Consultant
Thomas.Dale.Jay@gmail.com
www.linkedin.com/pub/thomas-d-jay/26/aa3/499
www.thomasdalejay.blogspot.com

The Technology High Ground

Monday, February 18, 2013

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

In the previous weeks I've written two blog articles which speak to the engineering complexities and capital intensity associated with the current development of EUVL (Extreme Ultra Violet Lithography) technology. An intensive effort is under way to provide a next generation 13.5 nanometer EUV light source required to print ever smaller nanoscale transistors and computer chips. Moore's law is marching on to again double the number of transistors on a chip and is being fueled by massive investments by major players in the semiconductor industry. Recently Intel, TSMC and Samsung invested over $6 Billion in ASML, a large well capitalized lithography equipment industry leader based in the Netherlands. ASML in turn purchased Cymer a critical supplier of laser technology providing key components in ASML's product line. The major investment in ASML was to ensure timely development and availability of HVM (High Volume Manufacturing) certified EUV lithography systems for shipment in late 2013 and projected 450 mm HVM production two or three years hence. EUV source development has been problematic and presents many challenges. Xtreme Technologies/Ushio and Gigaphoton and others are competing in the EUV source market with well funded programs. These efforts are being coordinated with imec, a major research and development center in Belgium. While billions are being spent on developing laser based, Sn plasma source technologies, innovative and cost effective engineering solutions are being researched with out the capital infusion and celebrity afforded some of the world's largest semiconductor equipment manufacturers.

Enter Zplasma. Funded by the U.S. Department of Energy in 1998, the University of Washington in Seattle, U.S.A., began construction of a ZaP Flow Z-Pinch Experiment. Henry Berg, an entrepreneur-in-residence at the university, started working with Nelson and Shumlak in 2011 to design and create a 200 watt commercial light source based on Sheared Flow Stabilization (SFS) technology, and then designed a proof of concept prototype to prove that the physics worked at the reduced size necessary for optical compatibility with steppers. Realizing that with xenon gas SFS produces a long pulse of EUV light at a wavelength of 13.5 nanometers, and that the semiconductor industry needed light sources of this type, the university filed for and was granted two patents on the invention. Zplasma was formed with Henry Berg as its CEO. The university and Zplasma executed an exclusive license agreement covering the two patents and the transfer of the commercial source prototype to Zplasma. More information on Zplasma may be found here at the company's web site.

During my most recent visit to the Zplasma website I sent a request to info@Zplasma.com for more detailed information on the company and its Z-pinch EUV source technology. Expecting a response from a MARCOM staffer I received a reply directly from Henry Berg, Zplasma's CEO. Having many questions about Zplasma and its Xe based EUV source technology, Henry and I exchanged questions and answers via email which allowed me to gain additional insight into Zplasma's feature/benefits and their significance given current concerns with impediments to HVM (High Volume Manufacturing) EUV source development. Much of the content of this blog entry is verbatim response to my questions from Henry Berg discussing the salient points of Zplasma technology and its differentiation from competitive EUV source technology. After discussion with Henry I thought this format might be the best way to convey a thorough discussion on a variation of Z-pinch ion source design in advance of SPIE Extreme EUV Lithography IV later this month.

I should point out that during the course of my blogging activities I have never held any financial interest in any of the companies or organizations I have mentioned. I've ceased my market trading activities over a year ago and currently do not hold positions in any stock or security (this disclosure does not preclude possible future investment or interest activities). My immediate interest is in rejoining active participation in the semiconductor industry which has been my career, and contributing meaningful discussion to critical issues facing our industry. In my opinion, Zplasma's patented technology could be of great interest to the EUV lithography community and the larger semiconductor industry. SPIE Advanced Lithography 2013 is an excellent opportunity for the EUV lithography community to initiate a thorough evaluation of Zplasma. What follows below is a brief introductory description of Zplasma's current research and development effort as conveyed by Henry Berg. The questions related to the following discussion are mine followed by Henry's well articulated answers.

Henry Berg, CEO Zplasma, Inc.
“When we started the commercialization effort two years ago, I did not anticipate that it would be so incredibly difficult to get industry support to develop this technology. The primary barrier has been that since nobody has ever stabilized an EUV-emitting plasma before, the industry has no understanding of the benefits of a stable plasma. Every previous source of EUV light has been based on unstable plasma, where you have a very brief time to produce as much EUV light as possible, hence the focus on CE, the switch to molten tin and industrial lasers, and all of the problems with debris damaging the collector optics.We are very excited about the potential our source has to enable high volume EUV lithography. Our source technology is so much simpler than LPP or LDP that it will not only be much less costly to build and to operate, but it will also be durable and reliable. We need financial and development support to take the prototype we have and develop it into the HVM source it needs to become.”

Discussion

Zplasma's Xenon Plasma EUV Source Technology

Questions by

Thomas D. Jay, Semiconductor Industry Consultant

Answers provided by

Henry Berg, CEO Zplasma, Inc.

Could you explain Zplasma's Z-pinch function, its vacuum pressure regime, and plasma formation process?

"The vacuum chamber is pumped down to a few microtorr. A small amount of xenon gas is then injected. Power is applied to ionize the gas into plasma. The plasma is accelerated. The Z-pinch forms from the flowing plasma, pinches down and the central portion of the pinch emits a pulse of EUV light. The available plasma is consumed, the pinch dims, and the plasma exhaust exits through a small hole in the endwall of the outer electrode. There is a long time between pulses, our target operation at 7 kHz means there is a pulse every 143 microseconds. Since pulses last on the order of 10 microseconds, there is plenty of time for the gas plenum to recharge the acceleration region with gas for the next pulse."

In addition to the Z-pinch phenomenon are external magnets utilized to confine and/or control the plasma?
"No. Gas is injected into the annular space between an inner electrode and an outer electrode. The gas is ionized into plasma and accelerated axially. The inner electrode then has a rounded tip that allows the Z-pinch to form between the tip of the inner electrode and the outer electrode end wall. The outer electrode has openings to allow side-on optical collection of the light. The outer electrode also has a small hole at the end that allows the plasma exhaust to exit and be collected away from the optics."

What differentiates Zplasma's Z-pinch technology from competing systems?
"There are two things going on here. All DPP sources, including ours, use a Z-pinch. Gas is injected between two electrodes, ionized into plasma, and a pinch forms. Cymer and Xtreme both built DPP sources that worked this way. The problem was that the pinch that formed was highly unstable, so it blew apart. This meant that they couldn’t get meaningful high power levels without melting their electrodes, and even at low power levels debris was produced and they couldn’t collect enough light. Our core innovation is Sheared Flow Stabilization (SFS). With SFS, you inject the gas upstream of the pinch assembly point. The gas is ionized into plasma, and the plasma is accelerated axially and only then allowed to come together. The result is a Z-pinch which is stabilized by the moving plasma. The duration of the pinch can be adjusted by changing the amount of gas injected or adjusting the input power waveform."

Is there a specific plasma pressure regime which optimizes the Sheared Flow Stabilization effect?
"Sheared Flow Stabilization requires the gas to be injected into the acceleration region in a certain way and with a certain uniformity to create the proper sheared flows in the plasma. Unlike unstable discharges, our input waveform can significantly affect the duration of the pulse, we will optimize our output pulses in this manner for maximum EUV output. We have deliberately not factored in any such optimizations that we are not sure about. We do not have a power supply capable of outputting an adjustable waveform."

Your literature comments, “The duration of the pinch lasts ten to a hundred times longer than other Z-pinches (quoted at 100 nanoseconds), then has a controlled end.” Please describe all of the parameters acting on a “controlled end” to the pinch.
"The length of the pinch can be stretched by adding more gas and stretching the input power waveform. The pinch has a natural end because the available gas is consumed, but it fades quietly rather than ending explosively like the other DPP sources. You can also end the pinch early by ramping down your input power waveform. There are six critical advantages to SFS:

a) Longer Light Pulse: SFS pulses are 10 to 100 times longer due to their stable nature, allowing for more light collection.

b) High Power without High CE: Long SFS pulses and side-on optical collection access increase throughput and lower required CE, enabling HVM operation with xenon and eliminating the need for molten tin.

c) No Debris: SFS ends the plasma pinch without explosive termination, eliminating high-energy debris.

d) Low Instantaneous Power: SFS pulses allow for EUV light production without the high instantaneous power levels that cause electrode thermal stress and ablation.

e) Dose Uniformity: SFS allows the length of each EUV pulse to be adjusted under control of the power supply, allowing for extremely accurate dose uniformity.

f) Adjustable Geometry: SFS makes pinch geometry adjustable for optical matching to stepper IF."

What is the current Xe Z-pinch EUV source CE (energy Conversion Efficiency)?
"Our prototype CE is limited because we are powering it with a capacitor bank that rings. A proper pulsed power supply that can shape the output waveform will solve that problem. We have 2% BW CE of 0.5% in the lab now, that will go to 1.5% with the right power supply."

Given sufficient funding, what is the projected CE on a larger, scaled for power Z-pinch EUV source?
"Stable plasma means we do not need to focus on improving CE. Our 200W target assumes we never get more than 1.5%. Of course, we will be optimizing CE as well to increase beyond that. The theoretical CE limit with xenon is 2-4%."

Does the Zplasma ion source provide increased Xe CE when compared to competing Xe EUV source designs? If so what is the percentage in CE gain?
"All discharge-produced-plasma sources (Cymer DPF, Xtreme DPP, Zplasma Stable DPP) use a Z-pinch as the core EUV-producing mechanism. SFS is what has driven our current CE so high despite the ringing capacitor bank, we are already where Cymer and Xtreme were with optimized power supplies. Our HVM 200W target assumes we only get to 1.5% CE, but we will optimize for higher CE as part of the development process, and I would love to see us exceed 2%. But we didn’t assume ANY new inventions or innovations to hit 200W, so improvements would just drive us over 200W."

What components must be scaled to achieve desired HVM power levels?
"We need a high voltage pulsed power supply that can run at 7 kHz and we need to couple the electrodes to a forced-flow chiller system for cooling."

Can you describe an optimal 7kHz power supply design specification or is there a commercially available model you've selected?
"We cannot identify a commercially available model, though I would love to use something off the shelf if possible. Other discharge sources have all used custom-built magnetically switched supplies, and our source would work with any of those supplies. 7 kHz was chosen so as not to push the limits of previously developed pulsed power supplies. Our plan is to build an IGBT-switched supply that is fully adjustable so we can stretch our pulses out even further and produce more EUV light. We have identified a partner who can produce the power supply we need."

What variable parameters must this source power supply provide (example: pulse width, amplitude, wave form shape, pulse rise time ramp)?
"The supply we would have made would allow all of these to be adjusted. There is a lot of exciting work still to be done extending SFS Z-pinches and increasing the amount of EUV light that is produced from each pinch."

Would a new “scaled for power” HVM design be price and performance competitive with other EUV systems of similar HVM performance?
"Our source technology is much cheaper and simpler than other ways of generating EUV light. There are no other systems of similar HVM performance, but I estimate that our source will be about 10x cheaper to make and 5x cheaper to operate than the present HVM EUV sources."

What is the peak resolution at 13.5 nm for Xe EUV spectra? Is there comparable (or better) spectral resolution and out of band performance for Xe Z-pinch as compared to a Sn source?
"EUV source power is measured in a 2% bandwidth around 13.5 nm, thus 2% BW EUV. Radiation outside of this region is called out-of-band (OOB) radiation. So our goal is to deliver 200 W of 2% BW EUV to the stepper intermediate focus (IF). We produce the same light as previous DPP sources, but do it from a much smaller EUV emission volume and in a stable manner. I haven’t talked about it much, but our OOB results should be outstanding. We do not have the OOB light from a laser to contend with. Our source will need to be coupled with an ellipsoidal multilayer mirror to couple the light to the IF. One cool thing about how that works is Bragg layer reflection will reduce the transmission of any OOB light that is present. But it is not having to worry about light from a laser pulse that is the main OOB differentiator."

Given SFS and your comments on dose error, does Zplasma's Z-pinch produce fewer neutrals than Sn based plasma systems?
"One key advantage of SFS is that you can shorten or lengthen the duration of the pinch under control of the power supply. So the source can adjust based on light being delivered to the IF to keep the EUV light energy dose within very tight bounds. There will be no significant debris from the source, as the root cause of high-energy debris is the violent instabilities in the plasma. Present LPP and LDP sources have an exploding Sn plasma droplet, so high energy ions and fast neutrals are both produced. Previous DPP sources all had the xenon Z-pinch that blew apart, also showering out debris. Our core focus has been eliminating the root cause of the DPP debris. Once we have our source operating, we will place optical collector coupon material in the right places and conduct durability tests. In theory, fast neutrals are produced by collisions with fast ions, so the dramatic reduction in fast ions should reduce fast neutrals. Our plasma is also moving orthogonally to the collector optics, so no debris mitigation is needed."

With a reduced debris profile utilizing Xe instead of Sn source feed material, will the system accommodate an H2 plasma cycle for mitigation of residual Xe induced particulates or surface contamination of the source/optics?
"Our system would indeed accommodate an H2 plasma cycle if needed. We have done a whole bunch of runs with hydrogen as part of our lab work testing the prototype. Our goal is to operate without generating any high-energy debris that hits the optics."

Given the reduction in high energy ions and fast neutrals is it possible to minimize or eliminate shot noise by ramping and shaping the power supply output and resulting EUV pulse characteristics?
"We do not know the answer to this question. It is possible that there will be shot noise variation compared to LPP/LDP based on how our source produces the photons, but we do not expect any differences, and I am not sure I see a mechanism that could result in differences. This is something that we will look at when we have the ability to do so."

If sufficiently funded, could an HVM, high power, Zplasma Z-pinch EUV source be delivered on time and in quantity to accommodate requirements at ASML and other stepper vendors?
"Yes, if ASML and/or Nikon fully supported the stepper integration process. Our focus is on the core technology to produce the light. We would need Carl Zeiss or Media Lario to make the mirror and Fraunhofer to make the mirror coating. Development of this technology with the right funding and support could be very rapid – no new innovations are required."

What is the estimated cost to scale components to desired HVM power levels?
"$6-8M to get to a fully functional 200W HVM prototype. This is for the core EUV-producing unit only. Stepper integration will require adding an ellipsoidal multilayer mirror."

Recent major R&D investments have been made in EUV source technology by Intel, TSMC and Samsung. Zplasma's EUV source design with all its potential features and benefits seems worthy of major funding in the “best of breed” competition currently in progress. With the approach of SPIE Extreme EUV Lithography IV in February 25 – 28, have you attracted new interest in funding?
“We are talking to several companies about financial backing and partnering with us to develop our source. Recently, we have been talking to IMEC, and are hoping to have further discussions with Global Foundries, Intel, TSMC, SK Hynix and Samsung at the upcoming SPIE conference in San Jose.”

If Zplasma's Xe Z-pinch EUV source can be scaled to power levels required for HVM at existing or further optimized CE levels, significant improvements in MTBF and debris mitigation might be achieved. A more simplified EUV source design with stable plasma operation could enhance dose uniformity and device product yields offsetting further diversification of investment in the search for optimal EUVL for HVM.

I'd like to thank Henry Berg for his personal response to my inquiries concerning Zplasma and his enthusiastic assistance in providing engineering data affording an insightful overview of his company.

Henry Berg, CEO of Zplasma will be attending SPIE Advanced Lithography, February 24 - 28, 2013 in San Jose, CA.

Thomas D. Jay
Semiconductor Industry Consultant
Thomas.Dale.Jay@gmail.com

http://www.linkedin.com/pub/thomas-d-jay/26/aa3/499
www.ThomasDaleJay.blogspot.com

The Technology High Ground

For more information on Zplasma visit www.Zplasma.com

For information on the SPIE Advanced Lithography 2013 Extreme Ultraviolet Lithography IV program click on the link below:
http://spie.org/app/program/index.cfm?fuseaction=conferencedetail&export_id=x12540&ID=x10947&redir=x10947.xml&conference_id=1039349&event_id=996835

Friday, February 1, 2013

The 13.5 nanometer Physical Cliff?

As SPIE Extreme Lithography IV approaches will the EUV lithography program fall off a physical cliff?

SPIE is the International Society of Optics and Photonics. Its membership is comprised of engineers who research the scientific manipulation and applications of light. On February 24-28 in San Jose, CA, a large contingent of SPIE membership will meet to discuss current progress on an exotic EUV (Extreme Ultra Violet) light source scheduled for implementation in next generation, nanoscale computer chip manufacturing. For those outside the semiconductor industry, EUVL (Extreme Ultraviolet Lithography) is a next generation, extremely short wavelength light source (13.5 nanometers) providing improved lithographic capability to print ever smaller, nanometer scale transistor circuit patterns on computer chips. The time and expense invested in the development of EUV lithography spans many years and totals billions of dollars. Recently, a few individuals (very few) have suggested to me that the physics challenges of 13.5 nanometer EUV lithography might be insurmountable and the continuing escalating expenditures to resolve EUV source power, uptime and mask issues (to name a few), will further delay the implementation of a work around strategy to preserve Moore's law. Moore politics in the semiconductor industry? The recently celebrated investments in ASML by Intel, TSMC and Samsung collectively approximate $6 Billion, the price of a new state of the art wafer fab. One might ask why not use these funds to build another foundry and utilize existing 193 nanometer manufacturing technology to creatively double or triple pattern DSA (Directed Self Assembly) device designs. This work around scenario might be an alternative in the shorter term but the economics and physics for this argument are not sustainable. At the 2011 EUVL Symposium, Rudy Peeters of ASML presented a compelling illustration (page 5 of his presentation) of the cost reductions attainable with EUV over 193 nanometer lithography. Given the same product (in one of his examples), a 193 nanometer process would entail as many as 5X the number of process steps with a >50% increase in cost. EUV's superior image resolution and higher k1 value at 13.5 nanometers extends lithography performance and ultimately reduces cost over time (k1 is a process evaluation coefficient that encapsulates process-related factors). These cost savings estimates are well within the ball park so long as critical EUV performance issues are resolved satisfactorily. Intel, TSMC and Samsung have invested heavily to ensure EUV performs on time. With additional time and expensive fine tuning, ASML will ramp production and Moore's law will again enable a new generation of semiconductor products, funding further R&D.

Is there an impending physical cliff for 13.5 nanometer EUV technology and beyond? Will complex physics issues limit EUV viability? The semiconductor industry confidently says no and is also in concurrent pursuit of BEUV (Beyond Extreme Ultra Violet) lithography as a follow on evolutionary path. BEUV 6.7 nanometer technology development will require additional time and investment and will no doubt foment additional engineering debate. Moore's law will be continually pushed to its limits but the current critical focus is on the timely delivery of HVM (High Volume Manufacturing) EUV lithography, and 450mm process/metrology tools. As the EUV program evolves, source designs will undergo modification and upgrades to reach required performance specifications but the over all program is moving forward. Semiconductor front end equipment manufacturers who are not EUV/450mm capable in a timely fashion risk the eventual loss of market share and possible forfeiture of future viability in the semiconductor manufacturing industry.

The key to success in the development of EUVL/BEUVL and related semiconductor technologies is the pooling of knowledge and distribution of R&D investment costs. The semiconductor foundries and consortiums have the capital resource to pursue technology development that can be cost prohibitive to a self funded corporate R&D program. However, collaboration on advanced R&D can be a delicate balancing act between managing intellectual property concerns and promoting the general welfare of a capital intensive industry. An excellent recent example of this concern is the protracted dispute between Apple and Samsung over intellectual property related to smart phone software. In spite of the on-going litigation, Apple A5 and A6 processors are being manufactured in an Austin, Texas wafer fab build by Samsung. Both companies benefit from the arrangement and share a major portion of the smart phone market place while making financial news headlines in the process.

Equally important to the pooling of financial resources is the cross linking of engineering groups collaborating on R&D programs. This interaction reduces development time by eliminating concurrent, redundant development programs and inefficient rediscovery of existing knowledge. As an example, I often recount an experience in which I visited a customer's corporate R&D facility to discuss a deep UV photostabilization application for his process. We began our discussion in the hallway outside his lab. After a few minutes our discussion attracted the attention of another resident researcher who happened by. Without introduction he stopped and silently listened in on our conversation. Our discussion began at 320 nanometers, a popular wavelength for photostabilization. We soon realized that a newly proposed process material would better stabilize at a higher wavelength in the 340 nanometer range. We wondered out loud where we might find a 340 nanometer range UV light source. Hearing this, our silent companion beamed a broad smile and blurted out, “I have what you're looking for. I fabricated a cadmium vapor lamp for an experiment years ago and haven't used it since then. I thought someone might need it one day. It's in my desk, I'll go get it.” We all laughed to celebrate a very brief but successful collaboration in which my customer discovered the answer to his question was a few doors down the hall from his lab. I didn't sell anything that day but planted the seeds for future collaboration and sales activity. I often wondered what the collaborative mean free path might have been in that laboratory, and how long it might have taken for my two friends to discover their in house problem and solution without my presence as a catalyst. A good semiconductor industry statistician can probably provide an answer, but that's another story.

Thomas D. Jay

Semiconductor Industry Consultant
ThomasDaleJay@gmail.com
www.linkedin.com/pub/thomas-d-jay/26/aa3/499
www.ThomasDaleJay.blogspot.com

The Technology High Ground

For information on the SPIE Advanced Lithography 2013 Extreme Ultraviolet Lithography IV program click on the link below:

http://spie.org/app/program/index.cfm?fuseaction=conferencedetail&export_id=x12540&ID=x10947&redir=x10947.xml&conference_id=1039349&event_id=996835

For additional information on the recent Intel, TSMC, Samsung investment in ASML, click on one of the referenced Bloomberg New links below:
http://www.bloomberg.com/news/2012-07-09/intel-agrees-to-buy-10-stake-in-asml-for-about-2-1-billion.html

http://www.bloomberg.com/news/2012-08-05/taiwan-semiconductor-agrees-to-invest-1-38-billion-in-asml.html

http://www.bloomberg.com/news/2012-08-27/samsung-to-buy-3-stake-in-asml-for-503-million-euros.html

http://www.bloomberg.com/news/2012-10-17/asml-to-buy-cymer-for-2-55-billion-to-speed-up-euv-development.html

For streaming updated technology news from Google, scroll to the very bottom of this page.

Thursday, January 24, 2013

The Scrum of All Fears

If you assemble the leadership of the world's largest semiconductor manufacturers, confront them with the critical tasks required to ensure on time development and delivery of EUV photolithography, what you'll get is the scrum of their fears.

On February 24-28 in San Jose, CA, the world's experts in the field of semiconductor photolithography will meet at the SPIE 2013 Advanced Lithography IV conference to present papers and report on the current development of 13.5 nanometer EUV (Extreme Ultra Violet) light source technology. Although significant progress has been made, the remaining tasks are formidable. Development activity continues to secure viable production worthy EUV lithography tooling for 14 and 10 nanometer scale devices on 450mm wafers. The scrum masters are afoot and if you're attending the SPIE conference in February, chances are you might be one of them.

Scrum? For the uninitiated, the term scrum as applied to product development was first referred to in the Harvard Business Review 86116: 137–146, 1986. Scrum is a management technique which emulates the activities on a rugby football field where team members repeatedly pass the ball forward to advance toward the goal. I won't elaborate further on scrum management here (see the referenced Harvard Business Review link below) other than to say it is probable many of us have been practicing elements of this technique for many years (unaware of it's current celebrity). While Director of Marketing at Veeco Instruments I scheduled daily early morning meetings with my staff (usually no more than ten minutes in length) to ensure current project goals were on target, tasks transitioned efficiently among managers, and obstacles were effectively circumvented. It seems to me that the semiconductor industry's management of the EUV photolithography initiative might be compared with a scrum strategy comprised of many teams reinforcing an international R&D effort. Billions of dollars are being strategically allocated by the world's largest semiconductor companies in a concerted effort to drive a program critical to all concerned. I couldn't resist the analogy to current developments in our industry and linkage to the tone of a Tom Clancy novel. Hence, the title of this essay.

Late last week I received comments on my blog questioning the efficiency with which EUV source development was progressing and how possible business/political influences might be favoring underperforming EUV R&D participants. Politics in the semiconductor industry? By now most are aware of the significant investments being made in ASML by Intel, Samsung and TSMC. Some may question the necessity for the investment. With ASML having almost twice the market capitalization of Applied Materials (ASML $29.31B, AMAT $15.22B on 1/23/2013) why was it necessary for three of the world's largest semiconductor manufacturers to invest additional billions in ASML? A review of the investments are in order: (Source: Bloomberg News)

Intel agreed on July 9, 2012 to purchase a 10% stake in ASML for $2.1B and later purchase another 5% for $1.0B. Additionally Intel will pay another $1.0B in scheduled payments to ensure the expeditious delivery of critical equipment to be purchased.

TSMC on August 5, 2012 agreed to purchase a 5% stake in ASML for $1.38B

Samsung on August 27, 2012 agreed to buy a 3% stake in ASML for $974M.

ASML on October 17, 2012 agreed to purchase Cymer for $2.6B. Scrum reset and goal to go.

For a combined $6B investment, Intel, TSMC and Samsung will collectively own approximately 23% of ASML facilitating ASML's purchase of Cymer for another $2.6B This affords the following benefits to the investor/players:

The strategic capital investment will sustain ASML/Cymer focus on EUV R&D in a difficult economy.

Sustains the ASML/Cymer EUV program in light of concurrent R&D by imec and Xtreme Technologies/Ushio and Gigaphoton, resetting a best of breed competition.

Focused EUV funding will help assure uninterrupted continuance of ASML/Cymer's existing 193 nanometer lithography product lines, negating possible resource concerns.

The investments should accelerate the delivery of ASML/Cymer EUV lithography systems by approximately 2 years.

The additional capital could fund ASML/Cymer development of alternative EUV source technologies, modifications to current designs, or the acquisition of external Intellectual Property as required.

Expedites the concurrent development of associated/complementary EUV technologies and accelerates, offsets and distributes the cost of transition to 450mm wafers.

Intel, TSMC and Samsung could establish rights to Intellectual Property developed by ASML/Cymer reducing future costs.

Provides investor/customer companies with priority shipment slots for ASML EUV systems.

Could vest Intel, TSMC and Samsung with influence over future ASML/Cymer activities.

Could enable ASML/Cymer to expand currently planned manufacturing capacity.

Could provide tax and/or investment savings for Intel, TSMC and Samsung.

Observations:

Xtreme Technologies/Ushio has demonstrated a viable hybrid EUV source utilizing rotating Sn disks as a feed/source while providing effective mitigation of Tin debris which can contaminate the EUV source optics. It is reported that the current EUV power output is 74 watts and MTBF numbers look favorable at this time. A path to higher EUV power output has been identified.

Gigaphoton has developed a proprietary pre-pulse laser technology with a CE (energy Conversion Efficiency) said to reach 5.2%. Is the recently announced Cymer pre-pulsed laser technology unique to ASML/Cymer, or is the technology licensed from Gigaphoton? Updated 2/20/2013 to note that Cymer was most recently granted patent(s) for laser pre-pulse technology on 4/17/2012 related to co-pending U.S. patent application 11/358,988 filed on 2/21/2006 entitled LASER PRODUCED PLASMA EUV LIGHT SOURCE WITH PRE-PULSE.

Why are the interests of Intel, TSMC and Samsung specific to ASML and Cymer? Why was there no additional investment from this group in Xtreme Technologies/Ushio or Gigaphoton? I suspect because there is confidence in the reported success of the Xtreme Technologies/Ushio EUV source installed in an ASML NXE:3100 series system at imec's 300mm fab in Leuven, Belgium. Gigaphoton has also demonstrated significant progress in its EUV source development and was the first to adapt laser pre-pulse technology to enhance EUV power output.

It seems that ASML and Cymer were viewed as being behind in the power curve (literally). However, in consideration of ASML's critical mass in the market place, it was recognized that the best economy of scale could be obtained by resolving Cymer's EUV source issues and tapping ASML's ability to ramp production when required. Cymer recently announced its own laser pre-pulse technology and appears to be recovering lost time. I suspect that Intel, TSMC and Samsung reacted to the stalled timetable at ASML and took steps to restore competitive EUV development there. The entire field of EUV technology vendors will undergo a review at SPIE Advanced Lithography IV and may prompt additional future maneuvering by Intel, TSMC and Samsung.

For many semiconductor equipment manufacturers, escalating single unit system prices are beginning to reflect a significant fractional percentage of their market capitalization. Example: ASML's current market cap is $29.31B. The current single unit price quoted for its EUV lithography system is $125M, which represents slightly less than half of 1% (0.00426) of ASML's market cap. A full production floor of EUV systems at ASML's new manufacturing facility (accommodating 8 EUV systems totaling $1.0B) represents approximately 4% of its market cap. While ASML's costs may be under control, if your company is valued at one billion dollars in market capitalization, can it afford to develop and support products with a $125M price tag? In today's semiconductor industry economy, strategic partnerships among capital investors, manufacturing consortiums and customers are becoming the norm, providing cost offsets and economies of scale that can sustain the viability of a capital intensive business model. As equipment costs spiral upward, DSA (Directed Self Assembly) techniques for nano-structures are gaining popularity as a possible means of off setting EUV lithography and complementary tooling costs.

It would appear that ASML and Cymer are playing catch up and making progress. Cymer had fallen behind in EUV laser source development while Xtreme Technologies/Ushio and Gigaphoton were making measured power output progress. A best of breed competition was stalling and required a reset. All things considered, the strategic time line for successful production worthy 450mm EUV lithography was in need of an insurance policy, and in the spirit of the capital markets, an additional reinsurance policy (the "insurance policies" being the recent investments made by Intel, TSMC and Samsung). Enter project managers and scrum masters from Intel, TSMC and Samsung. Strategic investments were made to ensure the timely availability of EUV technology and to establish the means by which future remedial assistance to strategic partners might be efficiently managed and financed. As I commented in a previous blog posting on January 5, “Research and development in self assembling semiconductor devices hold promise for the future. In the shorter term we are witnessing the evolution and self assembly of the next generation semiconductor industry.”

As for politics in the semiconductor industry, if you're planning to attend one of the luncheons during the SPIE Advanced Lithography IV conference, dim scrum won't be found on the menu.

Thomas D. Jay

Semiconductor Industry Consultant

Thomas.Dale.Jay@gmail.com
www.linkedin.com/pub/thomas-d-jay/26/aa3/499
www.ThomasDaleJay.blogspot.com

The Technology High Ground

For additional information on the SPIE Advanced Lithography 2013 Extreme Ultraviolet Lithography IV program click on the link below:
http://spie.org/app/program/index.cfm?fuseaction=conferencedetail&export_id=x12540&ID=x10947&redir=x10947.xml&conference_id=1039349&event_id=996835

For additional information on scrum management:

http://hbr.org/product/new-new-product-development-game/an/86116-PDF-ENG

For an update on current Cymer Pre-Pulse EUV source technology:

http://www.cymer.com/pre_pulse/

For information on Xtreme Technology/Ushio EUV source technology:

http://www.xtremetec.com/

http://www2.imec.be/be_en/press/imec-news/archive-2011/imecspielitho.html

For information on Gigaphoton's EUV source technology:

http://www.gigaphoton.com/e/news/20120703.html

For a link to a photo of imec's Extreme EUV tool: