Category Archives: LEDs

July 15, 2011 – Welcome to our third roundup of observations from SEMICON West 2011; we’ll be looking at LED technology and executive opinions on big-picture industry issues, and adding a few observations about the state of play in the solar market.

SEMICON West 2011
Day 1: SOI vs. FinFET, ReRAM vs. 3D NAND, and lots of video data
Day 2: A lithography-rich day
Day 3: Advancement in LED, exec perspectives, solar observations

LED improvements

The LED session at the TechXPOT venue was, like many of the other TechXPOT sessions, very well attended, with standing-room crowds, drawn by the prospect of an emerging semiconductor market with the potential to generate massive unit sales in the general lighting sector. Before this can happen on a mass scale, however, a steep reduction is needed in cost per lumen through a combination of performance boosts and manufacturing cost reduction. Speakers at the session reported progress in key areas, including efficiency, binning, epitaxy, manufacturing processes, and metrology.

On the performance side, the consensus is that efficiency for warm-light LEDs will increase from 100 lm/W today to 200 lm/W by 2020. An increase in input drive current from 350mA to 2A is one part of this process; it will also facilitate higher-power LEDs.

Unfortunately, nitride LEDs are plagued by the "droop" issue — at high operating currents, efficiency decreases. The origin of droop is still hotly debated, with the two leading hypotheses being carrier leakage and Auger recombination. The solution is tricky, as it requires growth of LEDs along non-polar or semi-polar crystal orientations (an area of active development), or reduction of carrier density in the active region by increasing the thickness of the quantum wells, which is not practical for high-power LEDs.

In the manufacturing cost arena, the primary focus in recent years has been on moving to larger wafers, reducing cost of ownership on front-end epitaxy, and improving overall packaged LED binning yields. The shift to 150mm substrates is expected to happen in under four years, compared to more than a decade for the 50mm-to-100mm transition. Top-tier LED companies are also eyeing larger substrates, but performance and yield remain challenging due to lattice and thermal mismatch between gallium nitride and silicon.

An interesting equipment trend is the race to make bigger, more efficient, MOCVD tools for nitride LEDs. Veeco has introduced the first production cluster tool for LEDs, while Aixtron recently announced a new record for wafer capacity (16 100mm wafers) for its Circus platform. Other approaches to reduce manufacturing cost, such as inline yield management and thin substrate handling during laser lift-off, are also being adopted.

Execs speak: Evolving adoption, favorite innovations

Wednesday afternoon’s Executive Summit, moderated by SEMI’s semiconductor business president Jonathan Davis, provided some interesting perspectives from top-level management.

Several panelists commented on evolving patterns of electronics consumption. Steve Newberry, president and CEO of Lam Research, noted that portable electronics are quickly becoming a necessity and not a luxury; Rick Wallace, his counterpart at KLA-Tencor, said he is bullish about the middle class using much more of its disposable income on electronics, and also about some 2 billion new customers who will want smart phones, music players, and other portable devices. Terry Brewer, founder and president of Brewer Scientific, commented on the importance of better user interfaces in this evolution, with Apple’s growth and success being testimony to this. (Davis had earlier pointed out that Apple recently became the largest IC buyer in the world, to the tune of $17.5 billion annually.)

When the topic turned to favorite innovations of the past year, Doug Neugold, chairman, CEO and president of ATMI, said he is getting a kick out of redeploying technology (such as material selectivity solutions for advanced ICs) towards handling electronic waste issues, like selective removal and recovery of metals from waste PC boards. Williams cited the use of laser-enhanced plasma in EUV illumination sources to create brightness five to ten times that of the sun.

Solar pricing, installation bottleneck, utility-scale concerns

Speaking of solar matters, there’s been at lot of talk on the show floor about plunging prices on solar modules, with reports of $1.20 to $1.30/watt or even less becoming common. While lower prices are in general a good thing, these levels (driven by a combination of declining demand in Europe due to fewer subsidies and a surge in manufacturing) are making life miserable for some in the startup community who had been planning on higher revenues.

Some are speculating that solar prices could become an international trade issue, with concerns that the large number of new producers in China may be dumping products below cost.

Another interesting aspect is that installation has become a bottleneck in the residential and commercial sectors; potential US demand at these lower prices cannot be fully realized given a general shortage of "boots-on-the-ground" experienced marketing and sales personnel generating an order pipeline. In part because of this, installers have not had to lower their prices despite lower module costs, so margins have improved. We talked to one Southern California installer who noted that a few months ago, he couldn’t get his calls returned when he wanted to buy panels; today, panel suppliers are calling him.

Utility-scale installations are a another challenge, however; financing and permitting remain huge issues, and the returns are still not broadly compelling at all-in costs of $3/watt or more when financial costs are included. Bankability is a much greater issue in this end of the market, while efficiency is top-of-mind in residential and commercial.

It will be interesting to see how the solar industry matures and if it evolves in a similar manner to what we have seen in semiconductors.

Overall, it has been another great year for the SEMICON/Intersolar shows!

by Michael A. Fury, Techcet Group

Click to Enlarge July 14, 2011 – Roaming the show floor is always a mix of nostalgia (old friends are still in the business), reassurance that a new generation has taken an interest in the industry, and just a touch of melancholy that great halls that used to have to turn away semiconductor suppliers due to over-subscription are now shared with other industries like MEMS, LEDs and other lighting, displays, and of course the sprawling PV infrastructure (Intersolar this year actually encroached into a section of the North Hall of Moscone, with the West Hall across the way full to bursting.)

Bobbi Rossi and the folks at Spartan Felt are continuing to nudge their product lines from industrial glass closer to the CMP space each year. In addition to hard pads that can compete with IC-1000 and ceria fix abrasive pads, they are producing zirconia and silicon carbide fix abrasive pads for other industries. But given the variety of new materials being using in semiconductor devices, it won’t be long before someone tries these exotic pads for some new CMP application.

SEMICON West 2011
Day 0: Market forecasts, supply-chain dynamics
Day 1: Intersolar wanderings, SEMICON West symposium
Day 2: CMP views, outlooks for breakfast
Day 2.5: Roaming the floor, LEDs, CMP pads, kudos to Napoleon
Day 3: Two eye-catching technologies in CMP slurry, printed electronics

Peter Pozniak of Malema Sensors gave me a guided tour of their Coriolis flow meters that can maintain stable liquid flow readings with 50% air entrainment, far beyond the point at which an ultrasonic flow sensor will give up in despair. The meters work equally well on clear fluids and fully loaded slurries; in the case of slurries, they can even report the density of the materials flowing through. I don’t understand enough of the fundamental operating principles to give away any state secrets, but it is based on an invention attributed to Napoleon (yes, the Bonaparte one), who noticed that cannonballs fired along east-west lines found their targets more reliably than those fired along north-south lines. The rotation of the earth was the culprit, and Napoleon learned how to compensate accurately for this Coriolis effect.

Eric Virey, LED analyst for Yole D

July 14, 2011 — ESI Inc. (Nasdaq:ESIO), laser-based manufacturing equipment supplier, uncrated the Model 5390 micromachining system for advanced LED via drilling and the AccuScribe 2600 LED wafer scribing system at SEMICON West.

The Model 5390 laser-based micromachining system creates electrical interconnections on LED packages, optimizing via placement accuracy.

It uses ESI’s high-speed compound beam positioner coupled with a high-power CO2 laser, enabling user-definable variable pulse width and pulse repetition frequencies of up to 300kHz. The system can produce more than 100 vias per second in typical single layer dielectric materials.

The first Model 5390 has shipped to an LED manufacturer.

ESI’s AccuScribe 2600 is built for high brightness LED (HB-LED) manufacturing, scribing patterned sapphire substrate (PSS), distributed Bragg reflector (DBR), metal mirror (MM) and other advanced wafers. HB-LEDs change LED architecture and manufacturing processes, said Jonathan Sabol, general manager of ESI’s LED

July 14, 2011 — MIT researchers used hydrothermal synthesis — a liquid-based method to grow submicroscopic wires — to fab a functional light-emitting diode (LED) array made of zinc oxide nanowires in a microfluidic channel.

The LED was manufactured at the lab bench under fairly benign conditions at low process temperatures, which may open up new substrate material options like flexible polymers and plastics. Researchers using a syringe to push solution through a capillary tube one-tenth of a millimeter wide. Capital-intensive semiconductor manufacturing processes and facilities were unneccessary. The microfluidic structure used to build the nanowires also packaged the final LED device. Testing was carried out continuously through the manufacturing process.

Nanomaterial geometry is coupled with electrical and optical properties, notes Brian Chow PhD 2008, so MIT uses its system to control nanowire aspect ratios — creating long thin wires, flat plates, etc. The researchers’ goal was to determine the controlling factor for nanowire shape and structure, said Jaebum Joo PhD 2010, now a senior research scientist at Dow Chemical Co. They discovered that aspect ratios could be tuned via the zinc oxide’s electrostatic properties in the growth solution. Ions of different compounds, when added to the solution, attach themselves electrostatically only to certain parts of the wire, which inhibits growth in that direction. Inhibition could be tuned by the specific properties of the compounds.

The manufacturing method could be ramped for large-scale production. Titanium dioxide and other materials may also be controllable in this manner, said  Joo, enabling flexible displays, solar cells, and other end products. Zinc oxide could be used to make batteries, sensors and optical devices in addition to LEDs.

The MIT team is also investigating fabricating "spatially complex devices from the bottom up, out of biocompatible polymers" with hydrothermal synthesis, Joo adds, targeting life sciences and medical applications.

The method developed out of discussions between Joo (nanomaterials), Chow (applied chemistry), and Manu Prakash PhD 2008 now an assistant professor of bioengineering at Stanford University (applied physics) about better ways to manufacture electronic circuits than the front-end fab, back-end package, test linear methods in use today.

The research was carried out with Media Lab associate professors Edward Boyden and Joseph Jacobson, and was funded by the MIT Center for Bits and Atoms, the MIT Media Lab, the Korea Foundation for Advanced Studies, Samsung Electronics, the Harvard Society of Fellows, the Wallace H. Coulter Early Career Award, the NARSAD Young Investigator Award, the National Science Foundation and the NIH Director’s New Innovator Award.

A paper describing the results was published July 10 in the journal Nature Materials. Access it here: http://www.nature.com/nmat/journal/vaop/ncurrent/full/nmat3069.html

Learn more at www.mit.edu

July 13, 2011 — Stanley T. Myers will retire as SEMI president and CEO later this year. At SEMICON West 2011, he tells Debra Vogler, senior technical editor, what moments stand out for him as "historic" advances in semiconductor fab and the evolution of SEMI. He also shares advice for young engineers entering the semiconductor industry.

In the early days, silicon engineers were finally able to make floats on crystal 1" in diameter. This led to the development of the 0 dislocation crystal, Myers says, which in turn prompted the semiconductor industry’s scale-up from 200 to 300mm wafers. The chip industry advances in this way, Myers notes, with one breakthrough building on another.

3D IC and through silicon vias (TSV) are fascinating technologies that will propel the continuation of Moore’s Law, Myers adds, looking to the semiconductor manufacturing industry’s future.

At SEMI, he considers most important the organization’s ability to bring together all members on global action items that matter to the semiconductor and adjacent markets. It was a historic moment for SEMI when the association created regional presidents and boards to focus on issues important to specific geographies, said Myers.

Advice for young engineers? "You’re going to do things and you’re going to fail…Fail well, fail fast, and move on," Myers advises, saying that this mindset allows you to accomplish anything. 

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July 12, 2011 – JCN Newswire — Tanaka Kikinzoku Kogyo KK will partner with SUSS MicroTec KK to develop pattern transfer and bonding technology using sub-micron gold particles. The companies hope to replace gold bumping, sputtering, and other technologies in MEMS, LED, and 3D IC packaging.

This joint development will encompass development of technology for transferring patterns of sub-micron gold particles to a silicon wafer at one time at the low temperature of 150C on a high-volume production basis. Using the transferred pattern of gold particles, which have an effect on absorbing wafer surface roughness, it is possible to achieve metal-metal bonding on a wafer level at 200C, enabling high temperature resistant hermetic seals and electrical connections.

The pattern transfer and bonding technology enables electrical connections and hermetic seals with the minimum necessary amount of gold material while also resolving issues faced when using current technologies: plating, screen printing, and sputtering, as well as micro-bump bonding technologies. The process aims to meet high heat conductivity, high heat resistance, narrow line width and narrow pitch goals for advanced devices.

Tanaka Kikinzoku Kogyo has developed manufacturing processes of a substrate for pattern transferring of sub-micron gold particles which offer higher heat resistance and lower stress than existing joints by soldering, and able to be bonded at low temperature due to its size effect. SUSS MicroTec will develop a wafer-level transfer and bonding equipment using such transfer substrates. This technology development is being carried out with the cooperation of Professor Shuichi Shoji and Associate Professor Jun Mizuno, Nanotechnology Research Laboratory, Waseda University.

Through the joint development, the two companies aim to begin sales of the transfer substrates and the transfer and bonding equipment in March 2012.

By implementing the bonding technology in packaging and assembly processes, manufacturers of micro electro mechanical systems (MEMS) devices, light emitting diodes (LEDs) chips and small-sized chip electronic components can form fine patterns on silicon wafers for sealing frames and electrodes at once without any waste and a 100% usage rate (the ratio of material that can be mounted on a product) of expensive gold material. The process can form hermetic seals in advanced MEMS, bump electrodes for high-brightness LEDs (HB-LED), and enable 3D packaging.

Tanaka Kikinzoku Kogyo and SUSS MicroTec will have a joint booth at Exhibition Micromachine/MEMS 2011 held at Tokyo Big Sight (Ariake, Koto-ku, Tokyo) July 13-15 at East Hall 2, booth B-05.

Tanaka Precious Metals has built a diversified range of business activities focused on the use of precious metals. Website: http://pro.tanaka.co.jp

SUSS MicroTec is a leading supplier of equipment and process solutions for microstructuring in the semiconductor industry and related markets. For more information, please visit http://www.suss.com.

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by Michael A. Fury, Techcet Group

Click to Enlarge July 11, 2011 – The day before the official opening of Semicon West 2011 started for this participant with the SEMI press conference. The group forecasts $44B equipment sales, 12% growth following 148% in 2010. Capital spending this year is driven by Intel, Global Foundries, and Samsung, with regional spending rankings led by Taiwan, the US, and Korea. Materials were up 25% in 2010 over 2009, and SEMI sees another 6% in 2011 to $46B. Materials spending by region is projected to be, in order: Taiwan, Japan, SE Asia, and Korea. There are 30,000 folks pre-registered for Semicon and Intersolar combined.

The SEMI/Gartner Market Symposium followed with a full room of ~150 people. Vincent Tong, senior VP of Xilinx, led off the session with his view of the supply chain dynamics critical to success at 28nm and beyond. Short-loop learning cycles of three months or less will play a key role in climbing yield curves not just for the semiconductor, but for the complete package, he advised.

Some changes are ahead in capital spending, foretold Bob Johnson, VP of research at Gartner. The impact of the March 2011 earthquake & tsunami in Japan is now being reported to been for only one quarter on the global electronics supply chain, due largely to the excellent efforts of Japanese vendors. Smart phones are well on their way to being the largest consumer of flash memory, which is forecast to have a total demand of 140,000 petabytes by 2015. Media tablet PCs are flagged as the next killer app as a semiconductor growth segment. A buildup of chip inventories has facilitated a push out of fab capacity expansion. Capex spending in 2011 will be up 12% over 2010, driven by Intel, foundries, and NAND, with a slight decrease in 2012 as inventory demand catches up. Capital concentration is continuing, with the top five chip producers spending 56% of the capital, and the top 10 spending 70%.

SEMICON West 2011
Day 0: Market forecasts, supply-chain dynamics
Day 1: Intersolar wanderings, SEMICON West symposium
Day 2: CMP views, outlooks for breakfast
Day 2.5: Roaming the floor, LEDs, CMP pads, kudos to Napoleon
Day 3: Two eye-catching technologies in CMP slurry, printed electronics

SEMI’s senior director of industry research & statistics, Dan Tracy, confirmed a sharp recovery in shipments of all wafer sizes in 2010, with 300mm shipments ~50% greater than 200mm shipments. Fab materials are forecast to be $24.8B in 2011, up 8.1% over 2010 with another 4.9% growth expected for 2012. Gold bond wire is being replaced by copper, but is still >80% of the market, with 80% of that gold wire <25

July 7, 2011 — Each high-brightness/high-power LED package is currently unique to its supplier, with diverse materials, packaging processes, and finished device reliability. TechSearch International has put out a study on HB-LED assembly trends and challenges, highlighting materials