Part of the  

Solid State Technology

  and   

The Confab

  Network

About  |  Contact

Posts Tagged ‘EUV lithography’

Next Page »

EUV Leads the Next Generation Litho Race

Friday, October 20th, 2017

thumbnail

As previously reported by Solid State Technology, the eBeam Initiative recently reported the results of its lithography perceptions and mask-makers’ surveys. After the survey results were presented at the 2017 Photomask Technology Symposium, Aki Fujimura, CEO of D2S, the managing company sponsor of the eBeam Initiative, spoke with Solid State Technology about the survey results and current challenges in advanced lithography.

The Figure shows the consensus opinions of 75 luminaries from 40 companies who provided inputs to the perceptions survey regarding which Next-Generation Lithography (NGL) technologies will be used in volume manufacturing over the next few years. “We don’t want to interpret these data too much, but at the same time the information should be representative because people will be making business decisions based on this,” said Fujimura.

Figure 1

Confidence in Extreme Ultra-Violet (EUV) lithography is now strong, with 79 percent of respondents predicting it will be used in HVM by the end of 2021, a huge increase from 33 percent just three years ago. Another indication of aggregate confidence in EUVL technology readiness is that only 7 percent of respondents thought that “actinic mask inspection” would never be used in manufacturing, significantly reduced from 22 percent just last year.

“Asking luminaries is very meaningful, and obviously the answers are highly correlated with where the industry will be spending on technologies,” explained Fujimura. “The predictability of these sorts of things is very high. In particular in an industry with confidentiality issue, what people ‘think’ is going to happen typically reflects what they know but cannot say.”

Fujimura sees EUVL technology receiving most of the investment for next-generation lithography (NGL), “Because EUV is a universal technology. Whether you’re a memory or logic maker it’s useful for all applications. Whereas nano-imprint is only useful for defect-resistant designs like memory.”

Vivek Bakshi’s recent blog post details the current status of EUVL technology evolution. With practical limits on the source-power, many organization are looking at ways to increase the sensitivity of photoresist so as to increases the throughput of EUVL processes. Unfortunately, the physics and chemistry of photoresists means that there are inherent trade-offs between the best Resolution and Line-width-roughness (LWR) and Sensitivity, termed the “RLS triangle”.

The Critical Gases and Materials Group (CGMG) of SEMI held a recent webinar in which Greg MacIntyre, Imec’s director of patterning, discussed the inherent tradeoffs within the RLS triangle when attempting to create the smallest possible features with a single lithographic exposure. Since the resist sensitivity directly correlates to the maximum throughput of the lithographic exposure tool, there are various tricks used to improve the resolution and roughness at a given sensitivity:  optimized underlayer reflections for exposures, smoothing materials for post-develop, and hard-masks for etch integration.

Mask-Making Metrics

The business dynamics of making photomasks provides leading indicators of the IC fab industry’s technology directions. A lot of work has been devoted to keeping mask write times consistent compared with last year, while the average complexity of masks continues to increase with Reticle Enhancement Technologies (RET) to extend the resolution of optical lithography. Even with write times equal, the average mask turn-around time (TAT) is significantly greater for more critical layers, approaching 12 days for 7nm- to 10nm-node masks.

“A lot of the increase in mask TAT is coming from the data-preparation time,” explained Fujimura. “This is important for the economics and the logistics of mask shops.” The weighted average of mask data preparation time reported in the survey is significantly greater for finer masks, exceeding 21 hours for 7nm- to 10nm-nodes. Data per mask continues to increase; the most dense mask now averages 0.94 TB, and the most dense mask single mask takes 2.2 TB.

—E.K.

Optimism Reigns at SPIE Lithography Conference, Despite Challenges

Tuesday, February 23rd, 2016

thumbnail

By Jeff Dorsch, Contributing Editor

Semiconductor manufacturing and design is growing increasingly complicated and just plain hard. Everyone knows that. The bad news is it’s only going to get worse.

Relax, there are many smart people gathered in San Jose, Calif., this week for the SPIE Advanced Lithography Symposium to discuss the challenges and figure out how to surmount them.

The changes required in lithography and related technologies to continue IC scaling promise to be painful and costly. Mitigating the pain and the cost is a common theme at the SPIE conference.

The annual SPIE Advanced Lithography conference is often dominated by discussions on the state of extreme-ultraviolet lithography (EUVL). In presentations on Sunday and Monday, the theme was generally the same as 2015 – EUV is making progress, yet it’s still not ready for high-volume semiconductor manufacturing.

Intel Fellow Mark Phillips said the technology has seen “two years of solid progress,” speaking Sunday at Nikon’s LithoVision 2016 event. He added, “There’s no change in Intel’s position: We’ll use EUV only when it’s ready.”

Anthony Yen of Taiwan Semiconductor Manufacturing covered the 30-year history of EUV development in his Monday morning presentation at the SPIE conference. Asked during the question-and-answer session following the presentation on when the world’s largest silicon foundry will use EUV, Yen stuck to the official company line of implementing EUV in production for the 7-nanometer process node, after some involvement at 10nm.

Seong-Sam Kim of Samsung Electronics also sees EUV realizing its long-aborning potential at 7nm, a node at which “argon fluoride multipatterning will hit the wall.” He touted the 80-watt power source Samsung has achieved with its NXE-3300 scanner from ASML Holding, saying it had maintained that level over more than eight months.

Intel’s Britt Turkot reported 200W source power “has been achieved recently,” and said the tin droplet generator in its ASML scanner has been significantly improved, increasing its typical lifetime by three times. EUV has demonstrated “solid progress,” she said, including ASML’s development of a membrane pellicle for EUV reticles.

While work with the ASML scanner on Intel’s 14nm pilot fab line has been “encouraging,” Turkot said, she added, “We do need to keep the momentum going.” Intel sees EUV entering into volume production with 7nm chips, according to Turkot. “It will be used when it’s ready,” she said.

EUV technology has shown “good progress” in productivity, while its availability and cost considerations have “a long way to go,” Turkot concluded, adding, “We need an actinic solution for the long term.”

An industry consensus has emerged that EUV will be used with ArF 193i immersion lithography in the near future, and this trend is likely to continue for some time, according to executives at the SPIE conference. There may also be wider adoption of directed self-assembly (DSA) and nanoimprint lithography technology, among other alternative lithography technologies.

Mark Phillips of Intel pointed to complementary implementation of EUV and 193i. “We must use EUV carefully,” he said. “We need to replace three-plus 193i masks.” Phillips added, “EUV can’t be applied everywhere affordably. 193i will continue to be used whenever possible.”

Nikon executives touted the capabilities of their new NSR-S631E ArF immersion scanner, introduced just before the SPIE conference. The new scanner can turn out 250 wafers per hour, and can be pushed to 270 wph with certain options, according to Nikon’s Ryoichi Kawaguchi.

Yuichi Shibazaki of Nikon said the company will next year introduce the S63xE scanner, improving on S631E.

For all the challenges of transitioning to 7nm and beyond, executives at SPIE remain optimistic about solving the issues of 193i multipatterning, DSA, and EUV. Harry Levinson of GlobalFoundries said in response to a question, “The ultimate resource is the human mind.”

SPIE Photomask Panel: Money Is An Issue

Friday, October 2nd, 2015

By Jeff Dorsch, Contributing Editor

The best things in life are free
But you can give them to the birds and bees
I want money
That’s what I want

Berry Gordy, Jr. and Janie Bradford wrote those lyrics in 1959 for the first hit song released by Tamla Records, later known as Motown. Barrett Strong was the first to record the song, which would be covered by The Beatles, The Rolling Stones, and many other artists.

“Money (That’s What I Want)” could have been the theme song for playing off the EUV Mask Readiness panel discussion on Thursday morning (October 1) at the SPIE Photomask Technology conference in Monterey, California.

Panelist Yalin Xiong of KLA-Tencor called for “a new model of discussing technology and economic terms” in developing inspection equipment for extreme-ultraviolet lithography photomasks and pellicles. “Long-term solutions that require investment are risky,” he said of actinic inspection technology, adding, “They require a new collaboration model.”

Xiong engaged with a fellow panelist, Jeff Farnsworth of Intel Mask Operations, in talking about such “economic terms” and forms of collaboration among mask shops, equipment vendors, and other parties in the semiconductor industry.

The KLA-Tencor executive asserted, “Photomask is an enabling technology for lithography. We have to make our voice heard.” He later added, “The voice [of the mask community] is not heard in lithography. We need to be louder.”

The last panelist on Thursday morning was Takahiro Onoue of HOYA, who reviewed the status of EUV mask blank manufacturing, where a substantial reduction in defects has been achieved in the past three years, he said.

Wrapping up his presentation, Onoue pointed to “economy” as “a significant challenge in 2015,” taking precedence over methodology and other key parameters. He added that “economic feasibility” is important to increasing production of defect-free, high-grade EUV mask blanks, and that will require “support from stakeholders for investment toward HVM [high-volume manufacturing].”

Onoue added for emphasis, “It’s very important.”

Funding and money issues aside, most of the panel session was devoted to discussion of technology issues in getting to HVM with EUV photomasks.

Farnsworth said during his presentation, “We’re serious about implementing EUV on 7 nanometer.”

Emily Gallagher of imec spoke about the necessity for pellicles to protect EUV masks. Handling of masks with pellicles can often add “large particles,” she said. While ASML Holding has a pellicle commercialization program well under way, Gallagher said the status of pellicles for EUV lithography is “not ready,” while adding there has been “a lot of progress.”

Chih-Cheng Lin of Taiwan Semiconductor Manufacturing reported that the foundry has been able to process 15,040 wafers in four weeks — an average of 518 wafers a day — using ASML’s NXE:3300 scanner this year, with tool availability increasing to 70.2 percent, compared with 55 percent during an eight-week period in 2014.

While ASML “has made a lot of progress” with EUV pellicles, Lin said, “the job is not done yet.”

The Week in Review: May 9, 2014

Friday, May 9th, 2014

SEMATECH announced this week that researchers have reached a significant milestone in reducing tool-generated defects from the multi-layer deposition of mask blanks used for extreme ultraviolet lithography, pushing the technology another significant step toward readiness for high-volume manufacturing.

University of California, Berkeley researchers sponsored by Semiconductor Research Corporation (SRC) are pursuing a novel approach to 3D device integration that promises to lead to advanced mobile devices and wearable electronics featuring increased functionality in more low-profile packages.

GlobalFoundries this week introduced an optimized semiconductor manufacturing platform aimed specifically at meeting the stringent and evolving needs of the automotive industry.

Peregrine Semiconductor announced shipment of the first RF switches built on the UltraCMOS 10 technology platform.

BASF inaugurated a new Electronic Materials Sampling and Development facility in Hillsboro, Oregon. The new facility is a strategic step towards establishing a North American footprint to supply materials for semiconductor manufacturing applications related to the electronics industry.

Veeco Instruments Inc. has appointed Shubham Maheshwari, 42, as its new Executive Vice President, Finance and Chief Financial Officer (CFO). Mr. Maheshwari replaces David D. Glass, who announced his retirement from Veeco last December.

Avago Technologies Limited and LSI Corporation announced Avago has completed its acquisition of LSI Corporation for $11.15 per share in an all-cash transaction valued at approximately $6.6 billion.

Microchip Technology Inc., a provider of microcontroller, mixed-signal, analog and Flash-IP solutions, this week introduced a new parallel Flash memory device.

The Semiconductor Industry Association announced that worldwide sales of semiconductors reached $78.47 billion during the first quarter of 2014, marking the industry’s highest-ever first quarter sales.

Qualcomm elected Harish Manwani to board of directors. Manwani brings more than 35 years of consumer product and global management experience, and currently serves as the Chief Operating Officer at Unilever PLC.

Blog Review: November 25, 2013

Monday, November 25th, 2013

Zvi Or-Bach, president and CEO of MonolithIC 3D, blogs about a recent announcement by Intel CEO Brian Krzanich on company expansion focused on a foundry plan. Or-Bach said that if Intel could keep the traditional 30% cost reduction per node from 28nm to 10nm, and the foundry’s cost per transistor is staying flat, then Intel would be able to provide their foundry customers SoC products at a third of the other foundries cost, and accordingly Intel should be able to do very well in its foundry business.

Vivek Bakshi, EUV Litho, Inc. reports on work presented at the 2013 Source Workshop (Nov 3-7, 2013, Dublin, Ireland), including data on the readiness of 50 W EUV sources to support EUVL scanners. At the meeting, keynoter Vadim Banine of ASML said that 50 W EUV sources have now demonstrated good dose control and are now available for deployment in the field. ASML also presented data on the feasibility of source power of 175 W at the first focus (720 W at source), and utilizing new, protective cap layers to give collectors six months of life.

At the GaTech Global Interposer Technology Workshop (GIT) in Atlanta, the pervasive theme appeared to be whether a change in substrate is required to lower overall costs and help drive HVM (high volume manufacturing) applications. Phil Garrou reports on the workshop, including presentations from Ron Huemoeller of Amkor and David McCann of GLOBALFOUNDRIES.

Pete Singer provides a preview of a special focus session at the upcoming IEEE International Electron Devices Meeting (IEDM), scheduled for December 9 – 11, 2013. The session covers many of today’s hot topics: memory, LEDs, silicon photonics, interposers, SOI finFETS and 450mm.

Dr. Lianfeng Yang of ProPlus Design Solutions, Inc., blogs that these days, circuit designers are talking about the increasing giga-scale circuit size. Semiconductor CMOS technology downscaled to nano-scale, forcing the move to make designing for yield (DFY) mandatory and compelling them to re-evaluate how they design and verify their chips.

Blog Review November 5 2013

Tuesday, November 5th, 2013

New blogs delve into the packaging technology of Apple’s A7, the road ahead for bulk FinFETs as defined by imec, with EUV is a gating factor for 450mm, split-manufacturing for U.S. trusted IC (TIC) program and Japan’s growing market for equipment and materials.

For the 10nm node and beyond, transistor research efforts are focused on high mobility designs with Ge and III-V channel, reducing VDD supply voltage as well as the subthreshold slope in transistors and optimizing multi-Vt designs. Pete Singer reports on work underway at imec in Belgium.

At the IEEE 3DIC in San Francisco Dan Radack of the Institute of Defense Analysis gave an update on the IARPA trusted Integrated Chip Program. Phil Garrou reports how it is now focused on split-manufacturing with FEOL done off-shore and BEOL done by trusted facilities in the U.S.

The A7 is manufactured by Samsung on a high-κ metal gate (HKMG) 28 nm process and the chip includes over 1 billion transistors on a die 102 mm2 in size. Phil Garrou reports on observations on the Package-on-Package (PoP) design as noted by fellow blogger Dick James. In an earlier blog, Dick described how the Apple A7 is using Samsung’s 28nm process.

Simon Favre of Mentor Graphics notes how EUV could possibly be a gating factor for 450mm. “Would you put in 450mm immersion steppers, and then yank them out to put in EUV before they’re fully depreciated?” he asks.

In advance of Semicon Japan, to be hold December 4-6 at the Makuhari Messe, SEMI’s Dan Tracy and Yoichiro Ando report that restructuring and consolidation has led to a new focus for the semiconductor manufacturers in Japan. As a result, the semiconductor equipment market in Japan will experience double-digit growth in both 2013 and 2014, driven by higher spending for memory production and in spending increases planned for the manufacturing of power semiconductors and “More than Moore” semiconductor technologies. Total equipment spending in Japan is estimated to reach $4.6 billion by 2014. Combining this with the $8 billion-plus spending on semiconductor materials, Japan represents a $12 billion market in 2014 for the suppliers of equipment and materials.

Research Bits: Oct. 22, 2013

Tuesday, October 22nd, 2013

Size matters in the giant magnetoresistance effect in semiconductors

Professors at Georgia State University reported that a giant magnetoresistance effect depends on the physical size of the device in the GaAs/AlGaAs semiconductor system.

In research that is supported by grants from the U.S. Department of Energy and the U.S. Army Research Office, Dr. Ramesh Mani, professor of physics and astronomy, studied the magnetoresistance in flat, very thin sheets of electrons in the ultra high quality GaAs/AlGaAs semiconductor with his colleagues Annika Kriisa from Emory University and Werner Wegscheider from the ETH-Zurich in Switzerland.

The researchers found that the change in the resistance or resistivity with the magnetic field depends on the size of the device. They demonstrated that, under the application of a magnetic field, wide devices develop a smaller and quicker change, while small devices develop a bigger but slower change in the resistivity. The resistance or resistivity of a material to the flow of electricity is a technologically important property, especially in semiconductors.

This research team developed a model to understand the observations and deduced that when the semiconductor system becomes of even better quality, the change in the resistance under the application of a magnetic field will become even bigger. Indeed, the change might become so big that the resistance vanishes entirely in the small magnetic field.

Thin film semiconductors that will drive production of next-generation displays

Researchers at the National Institute for Materials Science have developed a pixel switching semiconductor, which will be the key to driving next-generation displays, by using an oxide film with a new elemental composition.

When an oxide film contains metal with low bond dissociation energy, the thin film absorbs or desorbs oxygen easily and the conductivity of the film changes. For example, zinc has very low bond dissociation energy, so a thin film using zinc absorbs or desorbs oxygen easily when heated or cooled. This finding suggests that the manufacturing conditions for oxide semiconductors can be controlled by focusing on the bond dissociation energy. In fact, the research team confirmed that film deposition conditions can be broadened by adding silicon oxide with high bond dissociation energy to indium oxide. We also confirmed stabilization of thin-film conductivity in post-deposition heat treatment.

The research results are expected to be effective not only for reducing the power consumption of displays which consume about half of the power in rapidly diffusing smartphones, but also for achieving higher frequencies to realize higher-definition TVs. Additionally, the thin film developed in this research contributes to conserving precious resources by not using zinc, which is a trace element of concern, or high-cost gallium which is used in large quantities for galvanized steel sheets or as a rubber vulcanizing agent, while it also enables the manufacture of flat panel displays not affected by wild fluctuations in raw material prices.

Ultraviolet light to the extreme

When you heat a tiny droplet of liquid tin with a laser, plasma forms on the surface of the droplet and produces extreme ultraviolet (EUV) light, which has a higher frequency and greater energy than normal ultraviolet.Now, for the first time, researchers have mapped this EUV emission and developed a theoretical model that explains how the emission depends on the three-dimensional shape of the plasma. In doing so, they found a previously untapped source of EUV light, which could be useful for various applications including semiconductor lithography, the process used to make integrated circuits.

In the experiments, Andrea Giovannini and Reza Abhari from ETH-Zurich in Switzerland blasted a 30-micron-diameter droplet of tin with a high-powered laser 6,000 times a second. They measured the spatial distribution of the resulting EUV emission and found that 30 percent of it came from behind the region of the droplet that was struck by the laser. According to their model, this unexpected distribution was due to the fact that the plasma partially surrounding the droplet was elongated in the direction of the laser pulse.

Devices that produce narrow beams of EUV for purposes like in semiconductor lithography use mirrors to focus the emission. But, until now, no one knew to collect the EUV light radiating from behind the droplet.

Solid State Watch: September 27-October 3

Friday, October 4th, 2013
YouTube Preview Image

Defect-Free Mask Blanks Next EUV Challenge

Monday, September 16th, 2013

By Pete Singer

The next major roadblock to progress in the ongoing push to develop EUV lithography for volume production is the availability of defect-free mask blanks. According to Veeco’s Tim Pratt, Senior Director, Marketing, the tools in place today are not capable of producing mask blanks with the kind of yield necessary to support a ramp in EUV. “Based on the yield today, the mask blank manufacturing capacity can’t produce enough mask blanks to support the ASML scanners that they’re planning to ship,” Pratt said. “ASML is going to be delivering some light source upgrades in the field and when those start happening, the effective total wafer throughput of EUV scanners in the field is going to multiply and there’s just not the supply of usable mask blanks to be able to support those.”

The requirement for 2015 is to have zero blank defects larger than 62nm. SEMATECH in 2012 reported work showing eight defects larger than 50nm. “A lot of progress being made but the elusive zero defects has not yet been hit,” Pratt said. Veeco, which is the sole supplier of EUV multilayer deposition tools, has plans to upgrade the existing Odyssey tool and launch a new platform in the 2017/2018 timeframe.

Figure 1 shows an EUV mask, which is considerably more complicated than conventional photomasks. The EUV mask begins with a substrate. On the back of the substrate you have some material that’s used for chucking (an electrostatic chuck is used to hold the mask to a stage in the ASML tool and in the Veeco ion beam deposition tool). On top of the substrate is a multilayer sandwich made up of 40-50 moly silicon pairs that creates a mirror. A ruthenium capping layer helps protect the mask. The top layer is an absorber, and that’s what gets patterned.

The photo at the bottom right of Fig. 1 shows a small pit on the substrate. “As the multilayer gets deposited on top of it, you take what in the beginning might have been a small pit and at the top it becomes 1.5X or so larger,” Pratt said. “This a common problem with EUV. These very small pits and bumps on the substrate, because of the deposition angles, the way that the multilayer is put down, as small non-killer defect on the substrate suddenly becomes a killer after deposition.”

The left photo is a larger particle that fell on the blank during deposition. Pratt said that even if you could mill that down and make it level, you would just never get the reflectivity out of the section that you need.

Where is EUV today? Billions have already been invested to build the EUV infrastructure with particular emphasis on the light source. Chipmakers have invested in ASML, and ASML acquired light-source provider Cymer. There has also been a very large Industry investment in Zeiss to build the AIMS tool, which is a defect detection and repair system at EUV wavelengths.

In July, ASML said NXE:3300 scanner imaging and overlay performance reached levels where they are engaging with customers on a strategy for the 10nm logic node insertion (23nm half pitch). Good imaging performance was shown down to 13nm half pitch, and overlay between the NXE:3300 and NXT systems, had been demonstrated at less than 3.5nm. Good performance, stability and reliability of the pre-pulse source concept was demonstrated with a rate of around 40 wafers per hour, and ASML expressed confidence in reaching the goal of 70 wafers per hour productivity in 2014.

What could derail the EUV ramp, according to Pratt, is a supply of defect-free mask blanks. “EUV is, despite many years and many dollars of investment, not yet in production. The two main gaps are the EUV light sources and the defects on the mask. As they start to make progress, people start to look more seriously at the list of things to worry about for EUV going to production. Number one on that list is the mask defects. Mask defects can come from all different sources during the entire process, from the substrate all the way through to usage in the fab,” Pratt said. “The most dangerous (un-repairable) defects come from the ML (multilayer) coating process during mask blank manufacturing. You can’t clean them and you can’t repair them and if you have more than some very small amount, there’s really nothing you can do about it. You just have to throw that mask blank away and try again, which creates a very large selling price for the mask blanks. Not just because they are difficult to make but you’re throwing away a substantial amount of what you’re trying to sell,” Pratt said.

Click to view full screen.

Figure 2 illustrates the process flow for a EUV mask blank. After a substrate polishing process, the substrates goes from the substrate supplier to the mask blank supplier. At the mask blank supplier, they will deposit the multilayer, the fiducial mark and the deposition. The blank gets sold to the mask shop, which could be either captive or a merchant. That blank, which is basically a mirror at the point, gets patterned and inspected and sent off to the fab. Pratt said that once the mask hits the mask shop, there is a little more leeway in terms of the defects because the defects that occur in the mask show are usually on top. “It’s usually absorber type defects or patterning type defects and those are a lot more easily repairable,” he said.

Click to view full screen.

Figure 3 shows the timeline of Veeco’s system developed, starting with a research system developed in 1996 that went to Lawrence Berkeley. The was optimized in the 2003-2010 timeframe, which included work with SEMATECH in a joint development program. That basically turned it into what Pratt describes as an R&D system. “We have a system that is being used for all the mask blanks in the world. But those mask blanks are really R&D blanks that people use for print checks and reflectivity checking, but certainly nothing they would use in a fab yet, or expect to get yield off of,” he said. “A lot of the time, you don’t know if it’s yielding or not until the very end of the process.”

Pratt said they have seen some improvements when it comes to defects. “We’re not yet where we need to be for logic high volume manufacturing, but we’re getting close to where we need to be for memory.” The real issue is the low yield. “At the current yields, that mask blank makers would need to spend a whole lot of money, probably on the order of $3 billion or so, on capital to meet what the mask blank demand would be over the next five years. That’s just not feasible. EUV clearly can’t ramp in that scenario,” Pratt said.

Veeco is addressing the defect challenge in two ways. The short-term solution is an Odyssey upgrade. The longterm solution is a new platform. “The Odyssey upgrade improves the yield of the tool. But then longer term we think the next gen is needed, especially as you get out to years 4 and 5 where high volume manufacturing starts to occur,” Pratt said.

The ion beam deposition system in shown in Figure 4. The target assembly rotates, so the process might start off with silicon, the assembly is then rotated to deposit molybdenum and rotated again to deposit ruthenium. The problem is that the ion beam doesn’t always direct hit the target. “You might have some of these high energy ion missing the target and hitting the chamber. The chamber has shields on it, but that ion can bounce around and when it hits the shields, there’s a chance that it can knock off particles,” Pratt said.

The Odyssey upgrade will: reduce source to target ion overspray and reduce high energy reflected neutrals. New ion source optics are planned as well as a larger target size. Lower beam energy operation and lower pressure operation are also planned. Those should have two benefits.

Longer term, the next generation EUV ML system will focus on particles and CWL (center wavelength) process repeatability (CWL is a measure of how reflective the mask is). The new platform will minimize particle proximity, and accommodate new source technology. A larger chamber, out-of-plane deposition geometry, low-defect clamping and integrated endpoint control are also planned. Figure 5 shows progress in defect reduction from 2004 to 2012.

If you have some news to share, send me an e-mail at psinger@extensionmedia.com.

IEDM Preview: 20nm and Below

Sunday, November 11th, 2012

By Pete Singer

As the industry works to perfect 28nm devices in volume manufacturing and early 20nm processes, attention is focusing on next-generation 14nm and below technologies.

There have been three primary drivers in the semiconductor industry for the last four decades: Area, power/performance and cost. The well-known push to cram more functionality onto a single chip through continued scaling — or into a single package through 3D integration and other advanced packaging techniques — has been well documented. Today, with the exception of Intel, the industry’s leading edge devices in high volume manufacturing have critical dimensions of 28nm. Intel, racing ahead, introduced the 22nm IvyBridge chip in 2011 and has announced plans to have 14nm by the end of 2013. How long this kind of scaling can continue is the subject of some debate, with most recognizing the EUV lithography will be required at some point, most likely for the 10nm generation (Intel has said it doesn’t need it for 14nm).

It’s clear, though, that continued scaling is running out of steam, and that the industry most look for other means by which to say on the path defined by the proverbial “Moore’s Law.” Those advances are one of the primary focal points of the upcoming 58th annual IEEE International Electron Devices Meeting (IEDM), which will take place December 10-12, 2012 at the San Francisco Hilton Union Square. The conference will be preceded by a day of short courses on Sunday, Dec. 9 and by a program of 90-minute afternoon tutorial sessions on Saturday, Dec. 8.
As reported in last month’s issue, highlights of the IEDM 2012 technical program, which comprises some 220 presentations, include Intel’s unveiling of its industry-leading trigate manufacturing technology; a plethora of advances in memory technologies from numerous companies; IBM’s demonstration of high-performance logic technology on flexible plastic substrates; continuing advances in the scaling of transistors to ever smaller sizes, and breakthroughs in many other areas that will continue to move electronics technology forward.

Following, we’ve assembled a list of the “be sure not to miss” papers and sessions slated for IEDM 2012.

Invited papers

In the plenary session, imec’s Luc Van den hove, will describe how ultimate transistor and memory technologies are the core of a sustainable society. He says that several key societal challenges in domains such as healthcare, energy, urbanization and mobility call for sustainable solutions that can be enabled by combining various technologies. These solutions will be backboned by wireless sensor systems, smart mobile devices and huge data centers and servers, the key constituents of a new information universe. They will require extreme computation and storage capabilities, bound by (ultra)low-power or heat dissipation constraints, depending on the application. This drives the need, he says, to keep on scaling transistor technologies by tuning the three technology knobs: power/performance, area and cost. To get to ultra-small dimensions, advanced patterning integration, new materials such as high-mobility Ge and III-V materials, and new device architectures such as fully depleted devices are being introduced. This comes along with an increasing need for process complexity reduction and variability control. Equally important are the continued R&D efforts in scaling memory technologies. NAND Flash, DRAM and SRAM memories are now approaching the point where new scaling constraints force exploration of new materials, cell architectures and even new memory concepts. This opens opportunities for resistance based memories such as resistive RAM, phase-change RAM or spin-torque transfer magneto resistive RAM.

In another invited paper, in the regular sessions, researchers from Micron and Intel will discuss scaling directions for 2D and 3D NAND Cells. They note that many 2D NAND scaling challenges are addressed by a planar floating gate (FG) cell, which has a smaller aspect ratio and less cell to cell interference. Figure 1 compares a wrap FG cell (left) and a planar FG cell (right). The wrap cell is limited by a required aspect ratio of >10 for both the wordline and the bitline direction in a sub-20nm cell. The planar cell eliminates this limitation.

Of course, not all IEDM presentations are focused on leading-edge logic and memory. In the plenary session, John Rogers from the University of Illinois at Urbana-Champaign, will talk on bio-integrated electronics. He notes that biology is curved, soft and elastic, while silicon wafers are not. Semiconductor technologies that can bridge this gap in form and mechanics will create new opportunities in devices that require intimate integration with the human body. He plans to cover ideas for electronics, sensors and actuators that offer the performance of state-of-the-art, wafer-based systems but with the “mechanical properties of a rubber band.” He’ll explains the underlying materials science and mechanics of these approaches, and illustrate their use in bio-integrated, ’tissue-like’ devices with unique diagnostic and therapeutic capabilities, when conformally laminated onto the heart, brain or skin.In the third plenary talk, Joo-Tae Moon of Samsung Display will give a talk titled “State of the Art and Future Prospects in Display Technologies.” There are two parts which satisfy this vision, he notes. One is the picture quality and the other is design of the display. From picture quality point of view, bigger screen size and higher pixel density are the main factors. The need for a bigger screen size requires expediting technologies with lower RC delay and higher transistor performance. Higher pixel density mandates a smaller unit pixel area and each unit pixel has the dead space for the transistor and metal line which is protected from the light by the black matrix. Clearly, the design factor is the one of the main driving forces for the changes from CRT era to flat panel display era, he says.

Notable papers

imec, in a paper titled “Ultra Thin Hybrid Floating Gate and High-k Dielectric as IGD Enabler of Highly Scaled Planar NAND Flash Technology,” will describe — for the first time — a demonstration of ultra-thin hybrid floating gate (HFG) planar NVM cell performance and reliability. Results not only confirm the high potential of the HFG thickness scaling down to 4 nm with improved performance, but also show excellent post cycling data retention and P/E cycling endurance. The optimized ultra-thin HFG planar cells show potential for manufacture and scalability for high density memory application. Figure 2 is a TEM image of a polysilicon/TiN HFG cell. The stack consists of an ISSG tunnel oxide, a dual layer FG (PVD polysilicon + PVD TiN), a high-k IPD (ALD Al2O3) and an n-type polysilicon CG.

In a paper jointly authored by GLOBALFOUNDRIES and Samsung, titled “Stress Simulations for Optimal Mobility Group IV p- and n-MOS FinFETs for the 14 nm Node and Beyond,” researchers provide calculations of stress enhanced mobilities for n- and p-FinFETs with both Si and Ge channels for the 14nm node and beyond. Results indicate that both for nFETs and pFETs, Ge is “very interesting,” provided the correct stressors are used to boost mobility. Figure 3 is a XTEM of a Ge-channel FET with SiGe source/drain. They conclude that strained channels grown on a strain relaxed buffer is effective for 14nm nodes and scalable to future nodes. TCAD simulation trends are experimentally confirmed by nano-beam diffraction (NBD).

Luncheon presentation

Ajit Manocha, CEO, GLOBALFOUNDRIES, Inc. is sure to provide an interesting luncheon talk on Tuesday, December 11th, addressing some recent jabs from Intel’s Mark Bohr. The title of Manocha’s talk: “Is the Fabless/Foundry Model Dead? We Don’t Think So. Long Live Foundry 2.0!”

Manocha says that industry experts and observers have predicted for a long time that the fabless model has some cracks in it, and may in fact be headed for extinction at some point. “We in the foundry industry dismissed such chatter as we continue to enjoy growth rates that outpace the overall semiconductor industry,” he notes in his pre-conference abstract. “But it wasn’t until an executive from — surprise — Intel officially declared the fabless model is collapsing recently that many of us really got our feathers ruffled. We firmly believe that the rumors of its death are greatly exaggerated. Evidence would seem to support that it is actually the IDM model which is dead, survived only by a very small number of anomalies that have either the financial wherewithal or stubbornness to continue down this path.”

The foundry-based fabless model is not going away, and moreover it is driving manufacturers and device designers closer together, says Manocha. But like all living organisms, especially those in electronics, we have to continue to evolve. There are warning signs, both technical and economic, emerging in the foundry business that warrant our attention, and in fact require a re-thinking of how best to apply our resources and energy. Recent talks of fabless companies investing in their own fabs, and of foundries developing single company fabs’ underscore the sense of urgency. “Clearly, we must change – Call it Foundry 2.0,” he says.

Unprecedented technical and business challenges have driven semiconductor manufacturing to this new fork in the road. On the one side is the option to ‘go it alone’, an option available to less than a handful of companies. The temptation here is to circle the wagons, dig deep into the bank and develop an optimized, but relatively closed, solution that will hopefully work for most every need. Manocha said a second option, ironically, is a move toward a more IDM-like model. Strategic collaboration that creates a ‘virtual IDM-like interface’ to chip design companies will help further close the gap between process teams at the manufacturing companies and design teams at the fabless companies. “With daunting technical challenges like 3D stacking, 450mm fabs, new transistor architectures, multi-patterning, and the long-term viability of extreme ultraviolet (EUV) lithography, collaboration ‘early, often and deep’ is really the only practical approach given the cost and complexities involved,” he said.

Evening panel

One of the two evening panels on Tuesday at 8pm is titled “The Mighty Little Transistor: FinFETs to the Finish or Another Radical Shift?” The moderator will be Suresh Venkatesan of GLOBALFOUNDRIES. He notes that the 22nm node spelled the dawn of the fullly-depleted device architecture with the implementation of FinFETs as the workhorse of the technology. However, projecting out to the 10nm node and beyond the scalability of the FinFET architecture, the materials systems used to create it, and the fundamental electrostatics and parasitic components associated with the transistor once again loom large as significant challenges that need to be overcome.

Next Page »