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Wrap-up: SEMI’s Strategic Materials Conference

Tuesday, October 7th, 2014

SEMI’s Strategic Materials Conference was held September 30-October 1, 2014, in Santa Clara, CA at the Biltmore hotel.

By Karey Holland, Techcet Group

The 2014 Strategic Materials Conference was very well attended.  There were people from several of the leading IC makers as well as suppliers of equipment and materials to the fabs.  Unfortunately, the audio and video systems were not stellar, so we had to endure some ear shattering system noise, and any light image was not visible on the screens.  Otherwise, the venue was good.  Throughout the conference, several themes were repeated.

Focus on the stability we hope for in post 2013 times, but concern about volatility and uncertainty of the world economics, esp. the recession-like growth numbers in Europe and Japan expected for the next few years. While forecasters (Gartner, IC Insights, VLSI Research, Linx, Techcet Group and others) anticipate IC wafer starts growing at ≥6% CAGR over the next 5 years, there is concern that any number of geo political world problems could throw us back into a global recession.  Attendees had a greater concern than the presenters over the possibility of a future recession, and that the impact would be greater to IC industry now due to the entrenchment of mobile platforms.

Focus on cost of lithography as a driver for increased cost of leading edge MCUs/MPUs … with current nodes, multi-patterning requires many more expose/develop/dep/etch steps than EUV, but EUV has not yet met the requirements for manufacturing implementation.  It is likely that EUV will first be used for only a few critical layers.  DSA (directed self-assembly) may be used also for a few selected critical layers, but issues of defects will likely keep it from use in many layers.

Focus on the expected (and currently numerous options) for advanced devices and implications for materials.  This includes advanced packaging technologies.

450mm wafers may continue to slip, if the other large IC makers (e.g. TSMC, Samsung, GlobalFoundries) don’t agree with Intel on first implementation date/node. Collaboration across the entire ecosystem was stressed for 450mm to become a reality.

Below are things I found particularly interesting in the presentations and/or at the end of day panel discussions.

The key note presentation, “Materials Innovation for the Digital 6th Sense Era,” was by Matt Nowak of Qualcomm.  He discussed both the vision of the Internet of Things (IoT), the required IC devices (including analog & sensors) and implications to materials (and cost to manufacture) from these new IC devices; a perfect start to SMC 2014.  Qualcomm defines the Digital 6th Sense Era is “the augmentation of human ability”, or as Sue Davis put it “intelligent data based extension of our 5 senses ==>to a 6th“. Essentially this is where the ability of the IoT/IoE data feedback can act as our 6th sense by capturing data about one & one’s environment which results in  prediction/information being shared based on data collection and/or user selections regarding the environment around us (or about us, e.g., tele-health).”  Because the smartphone is the “most pervasive platform ever” (US Android users average 106 Apps launched/day), it can serve as a remote connection to the IoT world … be that monitoring our health, schedules, honey-do lists, and improving our understanding and enjoyment of the world around us.  For advanced logic one might expect, lithography for advanced ICs (quad patterning vs EUV) were discussed as key cost drivers.  Other required/expected advanced materials include high mobility channel materials and thin barrier metals (likely Co). Beyond CMOS, new structures and materials may be required to support sensors (bio, chemical, fluidic), nano batteries, piezo, thermal, and solar harvesters.

Mark Thirsk, Linx-Consulting, reviewed IC growth and lack thereof for past years, and observed that 2014 will be “first good year in 8 years” (since 2006), and forecast 6-8% CAGR for the next few years – strongly dependent on the success of the IoT.  IC market growth since 2010 correlates strongly to GDP since 2010, and thus regional GDP differences (e.g. the current European recession) are reflected in IC demand.  Technology challenges & opportunities in for the next 5+ years include advanced logic (3D NAND, and new memory method after 2018), numerous AL (atomic layer) processes, 3D / advanced packaging, patterning efficiency, and complexity.  The electronic materials landscape is changing: the supply chain is merging, and there are new entrants (esp. from Korea, Taiwan & China) in advanced materials such as photoresists. Interestingly, China appears to be focusing more on investing in fabless than fabs.

Duncan Meldrum, Hilltop Economics, said that the current subdued market growth (3% 2013-16) is due to more fiscal responsible people. China & Asia are growing 4 to 7.7%, US & Latin America about 2.1 to 3.1, Euro <2%, and Japan ~1.5%.  The tax increase in Japan is having a very negative impact. He expects the US to see a 5% year over year improvement (very good news) with our investments finally growing in 2nd half of 2014.  He anticipates healthy, but not stellar consumer spending through 2016.

Patrick Ho, Stifel Nicolas, initially discussed that for companies that follow Moore’s Law, that it is increasingly Fab capital intensity (Capex) with addition of FinFETs, new materials (e.g. High k), 3D NAND, and Multi-Patterning (from delayed EUV).  One can assume this will continue to be the case as CMOS devices moves from Si channel to replacement channel filled with SiGe, Ge, or III-V and memories move to new technologies such as ReRAM, STTRAM, etc.  His observation is that only Intel is pulling for 450mm, and if TSMC & Samsung don’t exert more pull, 450mm may not happen (esp. in light of the negative impact to equipment revenue per square inch of silicon).  The top 4 OEMs (ASML, KLA-T, Lam, AMAT) are large enough to push back on the top 3 IC makers, and that consolidation is continuing.  Patrick noted that all 4 top OEMs have dividends, and he anticipates that they will eventually get better valuations.  He showed a nice list of companies he thinks are acquisition candidates (CMC, Nanometrics, Nikon, Nova, Axcelis, Rudolph, Veeco, FormFactor, and Ultratech).  Other comments:  Moore’s law lives, but is under stress.  Innovation w/ or w/o EUV will bring industry back to Moore’s Law.  Changing landscape will help economics of leading players.

Ross Kozarsky, who leads Lux Research’s advanced materials team, discussed the longer range materials he investigates such as graphene, 3D printing, and Meta-materials. Graphene film sheets are of interest for transparent conductive materials (e.g. touchscreens), possibly moving to FETs & sensors.  3D printing has been around 30 yrs; today it’s used mostly for prototyping, but manufacturing use makes sense and could really increase total growth.  Multifunctional and multi-materials printers will be needed.  Autonomous cars are now a big growth opportunity, opening great opportunity for chemical and material companies to innovate.

Geraud Duboix, IBM Almaden, develops porous low k materials for interconnect passivation and their integration (esp. plasma damage).  In the 0.65 to 0.1um timeframe, interconnect RC delay was slowing devices even though the transistors were getting faster, and thus began the drive for lower k insulators.  The ITRS has been showing the need for lower k since its inception, but it also has pushed out the date of the more aggressive low ks.  Initially to achieve lower k, C and F were added to SiO2 to break-up network structure.  Today, they are driving low k down by adding porosity.  Once a big concern, Geraud said that ULK mechanical properties are now no longer a concern with UV treatment, the lowest k being integrated is 2.3-2.4, and new low k materials are emerging. Geraud is working on porous low k materials, to achieve lower k, and larger pores deliver lower k.  He discussed the various pore-sizes in evaluation, the importance of porogens (material in the low k deposition that is later removed to create pores) and methods being used to seal the created pores (especially before conformal barrier metal deposition).  Interestingly, he commented that creating and sealing the larger pores is somewhat easier, although he’s being asked to work on the smaller pores for now.  During the panel discussion Mansour Moinpour (Intel) asked why Geraud was working on smaller pores that are more difficult to fill. Geraud responded that for the designers insulators with 2.0 or 1.8 k would be too big a change and they want 2.4 and 2.2 first.

Todd Younkin, from Intel’s central research (components) novel materials group, discussed that the industry will continue CMOS Scaling through 7nm. As stated by others, lithography is a challenge and using several methods to accomplish patterning, while productivity and pattern placement (alignment) are concerns.  Intel is working on devices with channels of higher mobility materials that Si (III-V or MoS2) as well as beyond CMOS (e.g., GAA) devices.  Todd said that early in device research development, Intel works to make sure manufacturing should be capable of meeting cost expectations. These include the cost of multi-patterning versus EUV, ultra-low k interconnect materials, etc.

Angela Franklin, of TriQuint (recently renamed Qorvo) discussed the challenges of supply management (and unlike others, she projects well when talking, so we could avoid the audio system problems … thanks Angela!).  Angela educated the audience about Qorvo devices (some look more like MEMS with permanent epoxy “cavity” structures that resonate w/ the RF) which are significantly different from the leading edge logic and non-volatile most of us follow.  Unlike the device manufactures that use Si, Qorvo uses smaller substrates of III-V and GaN.  Many films are already on the substrates when purchased.  The fab process is very solvent intensive, and only 1/3 aqueous.  Unlike others, Qorvo uses significant eBeam lithography with up to 28 different resists and many negative resists, as well as metal lift-off (my first job at IBM >30 yrs ago).

Prof. Philip Wong of Stanford gave his typical dynamic and mind-stretching presentation. His discussion was focused on the single digit nodes, and the possible new channel materials for logic (III-V or 2D MoS2, MoSe2, WSe2, WTe2 or ??) and possible new devices, including carbon nanotube FET (CNFET), STTRAM, CBRAM, ReRAM (using HfOx, TaOx, TiOx).  He said that memory chips will hold 32Tbits.  He then smiled and said “none of this before the next 10 years”.  He showed some exciting interleaved memory and logic ideas using a base of 2D or 3D FETs, topped by STTRAM, then 2D or 3D FETs, and then 3D RRAM.  Because the interconnects of the bottom device are present, all processing for the others must be at low temperature (<400C).

Discussion Panel.  When asked about collaboration with materials suppliers, Intel and IBM research had significantly different responses.  Intel invests dollars and works with graduate students on advanced projects and hopefully a “lucky accident” brings advances.  IBM research mentioned that legal issues often get in the way of collaboration with suppliers.

Notes for SMC Day 2 2014 Blog

Tim Hendry, from Intel’s supply management team started off day 2.  A large concern he brought up was what he described as the widening connections between fab, material suppliers, and sub-suppliers.  He then discussed the concerns and possible ways to improve connections, as well as the importance of metrology and verification of chemical quality.  Unfortunately, some of the sub-suppliers are very big chemical companies that have difficulty getting excited about the low volume materials used to make ICs.  He finished up by saying that Intel is focused on controlling the costs of manufacturing that require close partnerships with materials suppliers. Intel is driving for unprecedented collaboration among the materials and sub tier suppliers to achieve cost, performance and defect targets.  The cost of packaging and shipping materials globally is driving investigation into new operating models to cut costs.

Dennis Hausmann of LamRC/NVLS discussed ALD/CVD in more details than others.  For Each CVD/ALD step, an average of $2-$3/wafer is added to manufacturing cost, while only about $1/wafer of this is for chemistry+power+exhaust management.  He reviewed at least 4 versions of ALD tools (furnaces to single wafer) and said that there is a “right ALD tool” for the right deposition job.  He said that single wafer tools with proper development can meet same throughput as batch furnaces.  However, if you look at the development cost, single wafer tools are much better in cost.  For depositions that improve with plasma ALD, single wafer tools also make sense.  An important observation by Dennis was that for ALD, sometimes it is the unknown contaminant that “makes it go”.  This is something that has been observed in the past of copper plating chemistries, as well as some CMP slurries.

James ONeil, CTO Entegris had an interesting title, which should fit most suppliers “Accelerating yield in a disruptive environment”.  James emphasized that suppliers need meaningful process discussions, insights & collaboration with their customers.

Adrienne Pierce of Edwards introduced SCIS collaboration to most of us.  This is a supply chain collaboration working group.  Some topics are tracing defects origins and BKMs for specific process (e.g. ALD).

There were then two parallel sessions; one on advanced memories and the other on 3D packaging.  In the memory session, Norma Sosa of IBM talked about PCRAM (phase change memory, which Micron has been shipping for a few years now), Mark Raynor, Matheson, discussed RRAM for Non-Volatile, and Suresh Upa, SanDisk, discussed packaging implications.

After the breakout, we had presentations from four materials supplier companies.  The four same very similar things.  Dave Bern of Dow Chemical discussed using the “right tool” for collaboration and the importance of making sure suppliers agree to work in areas that fit their “core competencies”.  Wayne Mitchel of Air Products noted that ICs are only 2% of GDP.  He agreed with Dave Bern that suppliers should only agree to work (partner) with customer on areas within expertise, otherwise it takes too much time and money to execute successfully. Jean Marc Girard, Air Liquide discussed the numerous risks of supply chain, from the sub-supplier, the environment (e.g. earthquakes), and materials stability (or lack thereof). Kevin O’Shea of SAFC Hitech emphasized that taking materials from a catalog of low volume and ramping to IC manufacturing needs is not trivial, and may also not be consistent with the materials manufacturer (the sub-supplier, or company that is “primary” in the materials).

The day 2 Panel discussion had more audience participation.  Some discussions I found particularly interesting are discussed below.

Tim (Intel) said the gap is getting wider between Intel, suppliers, sub-suppliers (esp. customs for IC industry). The large sub-supplier that doesn’t have an interest in moving forward – there is no motivation to increase metrology, metrics, etc.  The shrinking sub-supplier base isn’t good for our industry – reduction in cost per bit comes from shrinks and reuse of capital, not only lower cost materials..

Kurt Carlson said that sub suppliers don’t think IC fabrication is the best industry – the IC industry wants more and more, yet wants to pay less and less.  It’s not worth it to us (good sub-suppliers leave because it’s too costly for the small volumes).

Jean Marc said they don’t want to duplicate development costs, if they don’t need to; they would rather use universities and share on things like toxicology.

Dave said it costs millions of dollars to test materials, like EUV.

Mansour Moinpour asked about collaboration on liquid particle, GCMS, and similar – can we have joint & consistent measurements across the industry?  James Entegris responded that end user need to be drivers.  Jean Marc suggested that maybe SEMI standards could drive a standard of industrial analytics.

The value of roadmaps was very different to the various participants, however the idea of regulatory alignment and a roadmap related to this was generally thought to be useful.

The question of cost and logistics … there are some materials that require shipping a lot of water, which adds cost.  Intel said that they are getting into more cost sensitive mobile market and they may be driven to this rather than exact materials copy in near future.  Tim said the Intel CEO is “hell bent” that Intel will make money in the mobile market.  “Intel will pull it off.”

Solid State Watch: Sept. 25-Oct. 3, 2014

Monday, October 6th, 2014
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TSV Market Demand Now for Performance not Size

Wednesday, October 1st, 2014

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By Ed Korczynski, Sr. Technical Editor, SST/SemiMD

Through-Silicon Vias (TSV) have finally reached mainstream commercial use for 3D ICs, though still for “high-end” high-performance applications. Despite allowing for extreme miniaturization, the demand for TSV has little to do with package size as evidenced by recent Samsung and TSMC product announcements for “enterprise servers” and “routers and other networking equipment.”

Used to connect opposite sides of a silicon substrate to allow for stacking of multiple Integrated Circuit (IC) chips in a single functional package, the industry has been using TSV in Micro-Electro-Mechanical Systems (MEMS) and Backside Image Sensors (BSI) manufacturing for many years now. Also, the first announcement of a commercial FPGA product using TSV in a so-called “2.5D” interposer package happened four years ago.

(Source: Yole Devellopement)

However, the Figure above shows that CIS and MEMS and 2.5D-FPGAs can all be categorized as “niche” applications with limited growth potentials. Specialty memory and logic (and eventually photonics) applications have long been seen as the major drivers of future TSV demand.

On September 25 of this year, TSMC announced it has collaborated with HiSilicon Technologies Co, Ltd. to create an ARM-based networking processor that integrates a 16nm-node logic chips with a 28nm-node I/O chip using silicon interposer technology. This is the same 2.5D TSMC-branded Chip-on-Wafer-on-Substrate (CoWoS) technology used in the Xilinx FPGA product. “This networking processor’s performance increases by three fold compared with its previous generation,” said HiSilicon President Teresa He. Package size reduction has nothing to do with the value of the products now demanding TSV.

Samsung announced last August that it has started mass producing the industry’s first 64GB DDR4 registered dual Inline memory modules (RDIMMs) using TSV. Targeting enterprise servers and “cloud” data centers, the new RDIMMs include 36 DDR4 packages, each of which consists of four 4-gigabit (Gb) DDR4 DRAM dice. The low-power chips are manufactured using Samsung’s 20nm-node process. The company claims that the new 64GB TSV module performs twice as fast as a 64GB module that uses wire-bonding, while consuming about half the power. Samsung has invested in TSV R&D since 2010 for 40nm-node 8GB DRAM RDIMMs and 2011 for 30nm-node 32GB DRAM RDIMMs.

The Hybrid Memory Cube (HMC) and other heterogeneous 3D-IC stacks based on TSV should be seen as long-term strategic technologies. HMC R&D led by Micron continues to serve near-term customers demanding ultra-high performance such as supercomputers and performance networking, as detailed in an SST article from last year. Micron’s Scott Graham, General Manager, Hybrid Memory Cube, commented then, “As we move forward in time, we’ll see technology evolve as costs come down for TSVs and manufacturing technology, it will enter into future space where traditional DDR type of memory has resided. Beyond DDR4, we can certainly see this technology being for mainstream memory.”

Elusive Demand for Mobile Applications

14 years ago, this editor—while working for an early innovator in TSV technology—was co-author of a “3D stacked wafer-level packaging” feature article in SST.

The lead paragraph of that article summarizes the advantages of using TSV to reduce package sizes:

As electronics applications shrink in size, integrated circuit (IC) packaged devices must be reduced both in footprint and in thickness. The main motivation for the development of smaller packages is the demand for portable communications devices, such as memory cards, smart cards, cellular telephones, and portable computing and gaming devices. End-users of such electronic devices are interested in greater functionality per unit volume, not relatively simplistic metrics, such as transistors per chip or circuit speed.

While still true, established and inherently lower-cost packaging technologies have been extended to allow for stacking of thinned silicon chips:  wire-bonding can connect dozens of layers to a substrate, flip-chip with wire-bonding and substrate-vias can connect 4 layers easily, and both fan-in and fan-out packages can provide ample electrical Input/Output (I/O) connections. At SEMICON West this year in the annual Yield Forum breakfast sponsored by Entegris, Qualcomm vice president Dr. Geoffry Yu reminded attendees that, “TSV eventually will come, but the million dollar question is when. The market forces will dictate the answer.” What has become clear in the last year is that market demand for improved product performance will set the pace.

—E.K.

SPIE Photomask Technology Wrap-up

Tuesday, September 23rd, 2014

Extreme-ultraviolet lithography was a leading topic at the SPIE Photomask Technology conference and exhibition, held September 16-17-18 in Monterey, Calif., yet it wasn’t the only topic discussed and examined. Mask patterning, materials and process, metrology, and simulation, optical proximity correction (OPC), and mask data preparation were extensively covered in conference sessions and poster presentations.

Even with the wide variety of topics on offer at the Monterey Conference Center, many discussions circled back to EUV lithography. After years of its being hailed as the “magic bullet” in semiconductor manufacturing, industry executives and engineers are concerned that the technology will have a limited window of usefulness. Its continued delays have led some to write it off for the 10-nanometer and 7-nanometer process nodes.

EUV photomasks were the subject of three conference sessions and the focus of seven posters. There were four posters devoted to photomask inspection, an area of increasing concern as detecting and locating defects in a mask gets more difficult with existing technology.

The conference opened Tuesday, Sept. 16, with the keynote presentation by Martin van den Brink, the president and chief technology officer of ASML Holding. His talk, titled “Many Ways to Shrink: The Right Moves to 10 Nanometer and Beyond,” was clearly meant to provide some reassurance to the attendees that progress is being made with EUV.

He reported his company’s “30 percent improvement in overlay and focus” with its EUV systems in development. ASML has shipped six EUV systems to companies participating in the technology’s development (presumably including Intel, Samsung Electronics, and Taiwan Semiconductor Manufacturing, which have made equity investments in ASML), and it has five more being integrated at present, van den Brink said.

The light source being developed by ASML’s Cymer subsidiary has achieved an output of 77 watts, he said, and the company expects to raise that to 81 watts by the end of 2014. The key figure, however, remains 100 watts, which would enable the volume production of 1,000 wafers per day. No timeline on that goal was offered.

The ASML executive predicted that chips with 10nm features would mostly be fabricated with immersion lithography systems, with EUV handling the most critical layers. For 7nm chips, immersion lithography systems will need 34 steps to complete the patterning of the chip design, van den Brink said. At that process node, EUV will need only nine lithography steps to get the job done, he added.

Among other advances, EUV will require actinic mask inspection tools, according to van den Brink. Other speakers at the conference stressed this future requirement, while emphasizing that it is several years away in implementation.

Mask making is moving from detecting microscopic defects to an era of mesoscopic defects, according to Yalin Xiong of KLA-Tencor. Speaking during the “Mask Complexity: How to Solve the Issues?” panel discussion on Thursday, Sept. 18, Xiong said actinic mask inspection will be “available only later, and it’s going to be costly.” He predicted actinic tools will emerge by 2017 or 2018. “We think the right solution is the actinic solution,” Xiong concluded.

Peter Buck of Mentor Graphics, another panelist at the Sept. 18 session, said it was necessary to embrace mask complexity in the years to come. “Directed self-assembly has the same constraints as EUV and DUV (deep-ultraviolet),” he observed.

People in the semiconductor industry place high values on “good,” “fast,” and “cheap,” Buck noted. With the advent of EUV lithography and its accompanying challenges, one of those attributes will have to give way, he said, indicating cheapness was the likely victim.

Mask proximity correction (MPC) and Manhattanization will take on increasing importance, Buck predicted. “MPC methods can satisfy these complexities,” he said.

For all the concern about EUV and the ongoing work with that technology, the panelists looked ahead to the time when electron-beam lithography systems with multiple beams will become the litho workhorses of the future.

Mask-writing times were an issue touched upon by several panelists. Shusuke Yoshitake of NuFlare Technology reported hearing about a photomask design that took 60 hours to write. An extreme example, to be sure, but next-generation multi-beam mask writers will help on that front, he said.

Daniel Chalom of IMS Nanofabrication said that with 20nm chips, the current challenge is reduce mask-writing times to less than 15 hours.

In short, presenters at the SPIE conference were optimistic and positive about facing the many challenges in photomask design, manufacturing, inspection, metrology, and use. They are confident that the technical hurdles can be overcome in time, as they have in the past.

Blog review July 21, 2014

Monday, July 21st, 2014

Matthew Hogan, a Product Marketing Manager for Calibre Design Solutions at Mentor Graphics, blogs that SoC Reliability Verification Doesn’t Just Happen, You Know. He says the best way to verify multi-IP, multiple power domain SoCs, is with the Unified Power Format (UPF), which enables a repeatable, comprehensive, and efficient design verification methodology, using industry standards, at the transistor level.

Dick James, Senior Technology Analyst, Chipworks, has a TSMC-fabbed 20-nm part in-house, and is looking forward to the analysis results. Wondering what changes TSMC has made from the 28-nm process, Dick says he expects mostly a shrink of the latter process, with no change to the materials of the high-k stack, though maybe to the sequence.

Ed Korczynski continues his theme of “Moore’s Law is Dead” with a third installment that looks at when that might happen. He says that at ~4nm pitch we run out of room “at the bottom,” after patterning costs explode at 45nm pitch.

Vivek Bakshi, EUV Litho, Inc. blogs about The 2014 EUVL Workshop which was held late last month amid some positive highlights and lots of R&D updates. The keynote talks this year were from Intel, Gigaphoton and Toshiba.

In his 201st Insights from The Leading Edge (IFTLE) blog post, Phil Garrou takes a look at some of the presentations at this year’s ConFab. Subramani Kengeri, Vice President, Advanced Technology Architecture for GlobalFoundries discussed the techno-economics of the semiconductor industry. Gary Patton, VP of IBM Semiconductor Research & Development Center addressed “Semiconductor Technology: Trends, Challenges, & Opportunities.” Adrian Maynes, 450C program manager, discussed the “450mm Transition Toward Sustainability: Facility & Infrastructure Requirements.”

Zvi Or-Bach, President and CEO of MonolithIC 3D Inc., blogs that over the course of three major industry conferences (VLSI 2013, IEDM 2013 and DAC 2014), executives of Qualcomm voiced a call for monolithic 3D “to extend the semiconductor roadmap way beyond the 2D scaling” as part of their keynote presentations.

Scouting report for materials at end of the road: 2013 ITRS

Monday, May 12th, 2014

Ed Korczynski, Sr. Technical Editor, SST/SemiMD

The IC fabrication industry is approaching the end of the road for device miniaturization, with both atomic and economic limits looming on the horizon. New materials are widely considered as key to the future of profitable innovation in ICs, so everyone from process engineers to business pundits needs to examine the Emerging Research Materials (ERM) chapter of the just published 2013 edition of the International Technology Roadmap for Semiconductors (ITRS).

The 2013 ITRS covers both near-term (2014-2020) and long-term (2020 onward) perspectives on what materials and processes would be desired to build ideal ICs (Fig. 1, Table ERM15). However, to properly understand the information in the current edition we need to consider the changes in the IC fab industry since 1992 when the first edition of the ITRS’s predecessor was published as the U.S. National Technology Roadmap for Semiconductors (NTRS).

Fig. 1

Twenty-two years ago, the industry had dozens of fabs working on next-generation technology, and with lithographic scaling dominating innovation there was broad consensus on gradual materials evolutions. Today, the industry has 3 logic fabs and about as many memory lines pushing processes to smaller geometries, and each fab may use significantly different revolutionary materials. The result today is that there is little consensus on direction for new materials, and at best we can quantify the relative benefits of choosing one or another of the many options available.

In fact, with just a few players left in the game, there is much to lose for any one player to disclose strategic plans such as the use of revolutionary materials. Mark Thirsk, managing partner with specialty materials analysts Linx Consulting, commented, “We built our business based on anonymizing and generalizing the world, and then predicting the future based on big categorical buckets. But now there are a very few number of people pushing the boundaries and we’re being asked to model specific fab processes such as those for Intel or TSMC.”

For all of the above reasons, the current ITRS might be better understood as a scouting report that quantifies the roughness of the terrain when our current roads end. Exotic materials such as graphene and indium-gallium-phosphide may be used as alternate materials for the Si channels in transistors, novel stacks of atomic-layers may be used as electrical contacts, and spintronics and single-electron devices may one day replace DRAM and Flash chips for solid-state memory chips. However,  “significant challenges” exist in integrating any of these new technologies into high-volume manufacturing.

In the near-term, Cu wires clad with various metal barriers are projected to provide the best overall performance for on-chip interconnects.  As stated in the 2013 Executive Summary, “Unfortunately no new breakthroughs are reported for interconnections since no viable materials with resistivity below copper exist. However, progress in manipulation of edgeless wrapped materials (e.g., carbon nanotubes, graphene combinations etc.) offer the promise of ‘ballistic conductors,’ which may emerge in the next decade.”

Specialty Materials Suppliers

Fig. 2

Figure 2 (Figure ERM5) shows the inherent complexity involved in the stages of developing a new chemical precursor for use in commercial IC production. The chapter summarizes the intrinsic difficulty of atomic-scale R&D for future chips as follows:

A critical ERM factor for improving emerging devices, interconnects, and package technologies is the ability to characterize and control embedded interface properties. As features approach the nanometer scale, fundamental thermodynamic stability considerations and fluctuations may limit the ability to fabricate materials with tight dimensional distributions and controlled useful material properties.

In addition to daunting technical issues with pre-cursor R&D, the business model for chemical suppliers is being strained by industry consolidation and by dimensional shrinks. Consolidation means that each fab has unique pre-cursor requirements, so there may be just one customer for a requested chemistry and no ability to get a return on the investment if the customer decides to use a different approach.

Shrinks down to atomic dimensions means that just milliliters instead of liters of chemistry may be needed. For example, atomic-layer deposition (ALD) precursor R&D requires expertise and investment in molecular- and chemical-engineering, and so significant sunk costs to create any specialty molecule in research quantities. “We’ll have an explosion of precursors required based on proprietary IP held by different companies,” reminds Thirsk. “The people who are being asked to develop the supply-chain of ever increasing specifications are simultaneously being squeezed on margin and volumes.”

For materials such as Co, Ru, La, and Ti-alloys to be used in fabs we need to develop more than just deposition and metrology steps. We will also likely require atomic-level processes for cleaning and etch/CMP, which can trigger a need for yet another custom material solution.

Established chemical suppliers—such as Air Liquide, Dow, DuPont, Linde, Praxair, and SAFC—run international businesses serving many industries. IC manufacturing is just a small portion of their businesses, and they can afford to simply walk-away from the industry if the ROI seems unattractive. “We’re finding more and more that, for example in wet cleaning chemistry, the top line of the market is flat,” cautioned Thirsk. “You can find some specialty chemistries that provide better profits, but the dynamics of the market are such that there’s reduced volume and reduced profitability. So where will the innovation come from?”

Alternate Channel Materials

With finFETs and SOI now both capable of running in fully-depleted mode, alternative materials to strained silicon are being extensively explored to provide higher MOSFET performance at reduced power. Examples include III-V semiconductors, Ge, graphene, carbon nanotubes, and other semiconductor nanowires (NW). To achieve complimentary MOS high performance, co-integration of different materials (i.e. III-V and Ge) on Si may be necessary. Significant materials issues such as defect reduction, interface chemistry, metal contact resistivity, and process integration must be addressed before such improvements can be achieved.

Nano-wire transistors

Top down fabricated nanowires (NW) are one-dimensional structures that can be derived from two-dimensional finFETs. Patterned and etched <5nm Si NW have been reported to have room temperature quantum oscillatory behavior with back-gate voltage with a peak mobility approaching ∼900 cm2/Vs. Despite extensive R&D, grown Si NW demonstrate no performance improvements over patterned-and-etched NW, and controlled growth in desired locations remains extraordinarily challenging. Overall, significant challenges must be overcome for NW to be integrated in high density, particularly when targeting laterally placed NW with surround gates and low resistance contacts.

—E.K.

Solid State Watch: April 18-25, 2014

Friday, April 25th, 2014

Blog review April 7, 2014

Monday, April 7th, 2014

Pete Singer reveals the lineup of presenters for Session 1 of The ConFab, to be held June 22-25 in Las Vegas, and provides summaries of their talks. Speakers will be Vijay Ullal, COO, Fairchild Semiconductor; Dave Anderson, President and CEO, Novati Technologies; Gopal Rao, Senior Director Business Development, SEMATECH; Adrian Maynes, Program Manager, F450C; and Bill McClean, President, IC Insights.

Phil Garrou blogs about a variety of diverse issues this week, including GLOBALFOUNDRIES’ potential purchase of IBM’s semiconductor business, Altera’s separate deals with Intel and TSMC, why FinFET could be more expensive that more conventional CMOS strategies, as view by Handle Jones of IBS, and a new joint development program between ASE and Inotera focused on 3D IC packaging.

Blog review March 17, 2014

Monday, March 17th, 2014

Pete Singer is delighted to report that Dr. Roawen Chen, Senior Vice Present of global operations at Qualcomm, has accepted our invitation to deliver the keynote talk at The ConFab, on Monday June 23rd. As previously announced, Dr. Gary Patton, Vice President of IBM’s Semiconductor Research and Development Center in East Fishkill, New York, will deliver the keynote on the second day, on Tuesday June 24th.

Phil Garrou takes a look at what was reported at SEMI’s 2.5/3D IC Summit held in Grenoble, focusing on presentations from Gartner, GLOBALFOUNDRIES, TSMC and imec. He writes that GLOBALFOUNDRIES has been detailing their imminent commercialization of 2.5/3D IC for several years, and provide a chart showing the current status report. TSMC offered a definition of their supply chain model where OSATS are now integrated.

Bharat Ramakrishnan of Applied Materials writes about the importance of wearable electronics in the Internet of Things (IoT) era, and the role that precision materials engineering will play. He note that one key part of the wearables ecosystem that is still in need of new innovations is the battery. Two of the biggest challenges to overcome are the thick form factor due to battery size, and the lack of adequate battery life, thus requiring frequent recharging.

Blog review January 21, 2014

Tuesday, January 21st, 2014

Zvi Or-Bach, President and CEO of MonolithIC 3D weighs in on the battle of Intel vs TSMC in the foundry space, after conflicting stories appeared. One said that Intel had a huge pricing advantage over TSMC, and a second story noted TSMC’s boast that it was “far superior” to Intel and Samsung as a partner fab.

Adele Hars looks back at 2013 from the SOI perspective. In this “Part 2” post, she focuses on developments that last year brought in the areas of RF-SOI and SOI-FinFETs. Part 1 focused on the general SOI picture. Stayed tuned for a look at 2014.

Phil Garrou reports on some of the key 3DIC presentations from the IEEE Internal Electron Devices Meeting (IEDM), held in December in Washington, D.C. , focusing on papers from Micron, TSMC, Tohoku Univ., NC State and ASET. He said that Micron’s Naga Chandrasekaran addressed challenges in future memory manufacturing for both front end 3D NAND and back end 3DIC stacking, noting that he does not see any of the newer memory technologies making inroads against conventional DRAM or NAND in the next decade.

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