Category Archives: LED Manufacturing

Cree, Inc. announced a breakthrough in lighting-class LED performance with its SC5 Technology Platform. The new platform powers the next generation of lighting with the introduction of Extreme High Power (XHP) LEDs. This new class of LEDs can reduce system costs by up to 40 percent in most lighting applications.

“As a technology company, we’re focused on breaking the performance barriers that really matter to the lighting industry,” said Chuck Swoboda, Cree Chairman and CEO. “The SC5 Technology Platform redefines what is possible in high-power LEDs by doubling the lumens out of a single LED, giving lighting manufacturers the flexibility to innovate significantly lower cost systems. This new platform establishes a new benchmark for LED lumens per wafer, which we believe will define the long-term success of our industry. This also validates our belief that high-power LED technology enables the best lighting system designs and a better lighting experience for end customers.”

The SC5 Technology Platform is built on Cree’s silicon carbide technology and features significant advancements in epitaxial structure, chip architecture and an advanced light conversion system optimized for best thermal and optical performance. With these advancements, the SC5 Technology Platform achieves unparalleled lumen density and longer lifetime at higher operating temperatures than previous LED technology, which can significantly reduce thermal, mechanical and optical costs at the system level.

“LEDs are no longer the most expensive portion of an LED lighting system, but they fundamentally determine the overall system performance and cost,” said Dave Emerson, vice president and general manager for Cree LEDs. “While other LED manufacturers only promise incrementally lower LED cost, our new Extreme High Power (XHP) LEDs leveraging the SC5 Technology™ Platform directly address the increased burden that thermal, mechanical and optical elements now place on total system cost.”

The first available family of XHP LEDs is the XLamp® XHP50 LED, delivering up to 2250 lumens at 19 watts from a 5.0×5.0 mm package. At its maximum current, the XHP50 provides twice the light output of the industry’s brightest single-die LED, the XLamp XM-L2 LED, at a similar lumens per watt and without increasing the package footprint. By leveraging Cree’s latest reliability innovations, the XHP50 is designed to maintain L90 lifetimes above 50,000 hours even at high temperature and current.

The U.S. Patent Office has issued US Patent No. 8,859,310 to Versatilis LLC that shows how fine semiconductor particles, powders or fines, often the waste byproduct of dicing semiconductor wafers into ever smaller chips, can be processed into a sea of low cost solar cells or micro-LEDs.

A principal challenge in making such devices has always been forming the active layer, whether the light absorbing layer in a solar cell or the light-emitting layer in a LED. This has also been the most costly and capital-intensive part of the manufacturing process, since the active layer must be made to high standards of semiconductor crystal quality and uniformity. Leading solar cells, for example, use mono- or poly-crystalline silicon wafers, while LEDs use variants of Gallium Nitride (GaN) on expensive sapphire, Silicon Carbide or even GaN wafers. In many cases, these materials are thicker than needed, the added thickness lending structural support to the end device without adding to efficiency, but contributing to overall cost and weight of the structure.

Versatilis shows instead that the active layer can be made from semiconductor fines or powders of single crystal particles densely packed into a monolayer, in a configuration not unlike sandpaper one particle thick, and then further processed into active diode structures serving as solar cells, for example, or as LEDs. Such particles are readily available, often a byproduct of other processes or made inexpensively off-line, or sometimes chemically synthesized. Silicon fines, for example, are widely available, screened for a desired size distribution, as are CIGS and GaN particles, the latter chemically synthesized. And a small amount of such “dust” can go a long way; for example, a kilogram of one micron single crystal CIGS particles used as micro-solar cells can cover an area over 300 square meters, resulting in very low costs per unit area.

“By levering cheap, ex-situ produced and optimized, single or polycrystalline powders and fines for Si, Ge, CIGS, GaN, ZnO as the starting raw material and wrapping unique processing techniques around that, we can produce highly functional opto-electronic devices with reduced infrastructure, processing, and material utilization cost,” stated Ajay Jain, Versatilis CTO and inventor of the now patented technology.

The potential cost savings have led others to try using semiconductor particles in a variety of ways, however, none have proven commercially practical. A major challenge has been to lay down these particles quickly enough and as a monolayer. Similarly, researchers have shown basic functional devices with nanorods, nanowires and other semiconductor “nanostructures” in the lab, only to be stopped by a general lack of production ready manufacturing technology for nanoscale, including suitable tools for in-line process metrology and characterization.

In addition to processing semiconductor particles into useful devices, Versatilis has unique fluidics technology for rapidly depositing such particles as a monolayer, from nano to microscale, on wafers or in a continuous, high-speed web. It had licensed the technology to VersufleX Technologies (http://www.versuflex.com), who are beginning to sell benchtop process tools to R&D labs based on this technology. The process can tolerate reasonable variation in particle size and shape, and there are a variety of methods possible for orienting particles floating on the surface of a fluid medium.

“This technology will not set performance records for efficiency in PV cells nor in lumens/watt for LEDs, but we believe there is no cheaper, more practical way to realize semiconductor diode based functionality over a large, flexible area,” added George Powch, Company CEO, “We think it can enable low cost Building Integrated Photovoltaics or rival OLEDs with a wholly inorganic large area micro-LED solution.”

Even as the 2014 Nobel Prize in Physics has enshrined light emitting diodes (LEDs) as the single most significant and disruptive energy-efficient lighting solution of today, scientists around the world continue unabated to search for the even-better-bulbs of tomorrow.

Enter carbon electronics.

Electronics based on carbon, especially carbon nanotubes (CNTs), are emerging as successors to silicon for making semiconductor materials. And they may enable a new generation of brighter, low-power, low-cost lighting devices that could challenge the dominance of light-emitting diodes (LEDs) in the future and help meet society’s ever-escalating demand for greener bulbs.

Scientists from Tohoku University in Japan have developed a new type of energy-efficient flat light source based on carbon nanotubes with very low power consumption of around 0.1 Watt for every hour’s operation–about a hundred times lower than that of an LED.

In the journal Review of Scientific Instruments, from AIP publishing, the researchers detail the fabrication and optimization of the device, which is based on a phosphor screen and single-walled carbon nanotubes as electrodes in a diode structure. You can think of it as a field of tungsten filaments shrunk to microscopic proportions.

They assembled the device from a mixture liquid containing highly crystalline single-walled carbon nanotubes dispersed in an organic solvent mixed with a soap-like chemical known as a surfactant. Then, they “painted” the mixture onto the positive electrode or cathode, and scratched the surface with sandpaper to form a light panel capable of producing a large, stable and homogenous emission current with low energy consumption.

“Our simple ‘diode’ panel could obtain high brightness efficiency of 60 Lumen per Watt, which holds excellent potential for a lighting device with low power consumption,” said Norihiro Shimoi, the lead researcher and an associate professor of environmental studies at the Tohoku University.

Brightness efficiency tells people how much light is being produced by a lighting source when consuming a unit amount of electric power, which is an important index to compare the energy-efficiency of different lighting devices, Shimoi said. For instance, LEDs can produce 100s Lumen per Watt and OLEDs (organic LEDs) around 40.

Although the device has a diode-like structure, its light-emitting system is not based on a diode system, which are made from layers of semiconductors, materials that act like a cross between a conductor and an insulator, the electrical properties of which can be controlled with the addition of impurities called dopants.

The new devices have luminescence systems that function more like cathode ray tubes, with carbon nanotubes acting as cathodes, and a phosphor screen in a vacuum cavity acting as the anode. Under a strong electric field, the cathode emits tight, high-speed beams of electrons through its sharp nanotube tips — a phenomenon called field emission. The electrons then fly through the vacuum in the cavity, and hit the phosphor screen into glowing.

“We have found that a cathode with highly crystalline single-walled carbon nanotubes and an anode with the improved phosphor screen in our diode structure obtained no flicker field emission current and good brightness homogeneity,” Shimoi said.

Caption: This image shows a planar light source device from the front. Credit: N.Shimoi/Tohoku University

Caption: This image shows a planar light source device from the front. Credit: N.Shimoi/Tohoku University

Field emission electron sources catch scientists’ attention due to its ability to provide intense electron beams that are about a thousand times denser than conventional thermionic cathode (like filaments in an incandescent light bulb). That means field emission sources require much less power to operate and produce a much more directional and easily controllable stream of electrons.

In recent years, carbon nanotubes have emerged as a promising material of electron field emitters, owing to their nano-scale needle shape and extraordinary properties of chemical stability, thermal conductivity and mechanical strength.

Highly crystalline single-walled carbon nanotubes (HCSWCNT) have nearly zero defects in the carbon network on the surface, Shimoi explained. “The resistance of cathode electrode with highly crystalline single-walled carbon nanotube is very low. Thus, the new flat-panel device has smaller energy loss compared with other current lighting devices, which can be used to make energy-efficient cathodes that with low power consumption.”

“Many researchers have attempted to construct light sources with carbon nanotubes as field emitter,” Shimoi said. “But nobody has developed an equivalent and simpler lighting device.”

Considering the major step for device manufacture–the wet coating process is a low-cost but stable process to fabricate large-area and uniformly thin films, the flat-plane emission device has the potential to provide a new approach to lighting in people’s life style and reduce carbon dioxide emissions on the earth, Shimoi said.

Duke University researchers have made fluorescent molecules emit photons of light 1,000 times faster than normal — setting a speed record and making an important step toward realizing superfast light emitting diodes (LEDs) and quantum cryptography.

This year’s Nobel Prize in physics was awarded for the discovery of how to make blue LEDs, allowing everything from more efficient light bulbs to video screens. While the discovery has had an enormous impact on lighting and displays, the slow speed with which LEDs can be turned on and off has limited their use as a light source in light-based telecommunications.

In an LED, atoms can be forced to emit roughly 10 million photons in the blink of an eye. Modern telecommunications systems, however, operate nearly a thousand times faster. To make future light-based communications using LEDs practical, researchers must get photon-emitting materials up to speed.

In a new study, engineers from Duke increased the photon emission rate of fluorescent molecules to record levels by sandwiching them between metal nanocubes and a gold film.

This is an artist's representation of light trapped between a silver nanocube and a thin sheet of gold. When fluorescent molecules -- shown in red -- are trapped between the two, they emit photons up to 1,000 times faster than normal. Credit: Gleb Akselrod, Duke University

This is an artist’s representation of light trapped between a silver nanocube and a thin sheet of gold. When fluorescent molecules — shown in red — are trapped between the two, they emit photons up to 1,000 times faster than normal. Credit: Gleb Akselrod, Duke University

“One of the applications we’re targeting with this research is ultrafast LEDs,” said Maiken Mikkelsen, an assistant professor of electrical and computer engineering and physics at Duke. “While future devices might not use this exact approach, the underlying physics will be crucial.”

Mikkelsen specializes in plasmonics, which studies the interaction between electromagnetic fields and free electrons in metal. In the experiment, her group manufactured 75nm silver nanocubes and trapped light between them, greatly increasing the light’s intensity.

When fluorescent molecules are placed near intensified light, the molecules emit photons at a faster rate through an effect called Purcell enhancement. The researchers found they could achieve a significant speed improvement by placing fluorescent molecules in a gap between the nanocubes and a thin film of gold.

To attain the greatest effect, Mikkelsen’s team needed to tune the gap’s resonant frequency to match the color of light that the molecules respond to. With the help of co-author David R. Smith, the James B. Duke Professor and Chair of Electrical and Computer Engineering at Duke, they used computer simulations to determine the exact size of the gap needed between the nanocubes and gold film to optimize the setup.

That gap turned out to be just 20 atoms wide. But that wasn’t a problem for the researchers.

“We can select cubes with just the right size and make the gaps literally with nanometer precision,” said Gleb Akselrod, a postdoc in Mikkelsen’s lab and first author on the study. “When we have the cube size and gap perfectly calibrated to the molecule, that’s when we see the record 1,000-fold increase in fluorescence speed.”

Because the experiment used many randomly aligned molecules, the researchers believe they can do even better. They plan to design a system with individual fluorescent molecule placed precisely underneath a single nanocube. According to Akselrod, they can achieve even higher fluorescence rates by standing the molecules up on edge at the corners of the cube.

“If we can precisely place molecules like this, it could be used in many more applications than just fast LEDs,” said Akselrod. “We could also make fast sources of single photons that could be used for quantum cryptography. This technology would allow secure communication that could not be hacked — at least not without breaking the laws of physics.”

The 2014 Nobel Prize for physics awarded today to three physicists for their invention of blue light-emitting diodes (LED) led to a significant breakthrough and paved the way for the creation of white light—a cleaner, more energy-efficient and longer-lasting source of illumination that also has generated a multibillion-dollar market and the creation of hundreds of thousands of jobs, according to IHS Technology.

Following the invention of blue LEDs by Isamu Akasaki, Hiroshi Amano and Shuji Nakamura, white light could finally be achieved—either through a combination with previously invented red and green LEDs; or as more commonly seen today, by adding a yellow phosphor layer over the blue LED. Without blue diodes, white light could not be produced.

Since the trailblazing invention of blue LEDs in the early 1990s the LED component market has flourished, reaching an estimated $17.7 billion in 2013, as shown in the attached figure, and supporting more than 250,000 jobs in the industry. The overall market would be even bigger if it included all the LED downstream markets, such as lighting, displays, signage, consumer electronics and even Christmas lights.

2014-10-07_LEDs

William Rhodes, research manager for LEDs and lighting at IHS, said that the invention of Akasaki, Amano and Nakamura was a game-changer.

“Before the invention of blue LEDs, the market was mainly focused on indicator lights in toys, industrial and automotive applications,” Rhodes observed. “Since then the market has evolved with more than 90 percent of all displays sold this year backlit by LEDs, and LEDs will account for 32 percent of all bulb sales and revenue in 2014.”

The LED lighting market is poised for strong growth in the next five to 10 years with energy-hungry technologies being systematically banned across the world. In particular, consumers and business owners alike are increasingly looking for energy-efficient lighting for their homes and offices to replace energy hogs such as incandescent bulbs, which can use as much as six times the amount of electricity compared to LEDs.

All of this would not be possible without the ground-breaking work of this year’s Nobel Prize physics winners Akasaki, Amano and Nakamura, Rhodes said.

Seoul Semiconductor, a global LED manufacturer, announced the availability of Acrich MJT 3030 a new LED in the Acrich MJT product family which improves on performance and enables lower system costs. Using Seoul Semiconductor’s Acrich MJT technology, the MJT 3030 LED offers improved performance and high lm/$ in a mid-power package.

This new Acrich series has dimensions of 3.0mm x 3.0mm delivering a typical luminous flux of 103 lumens at 40mA at 22V, 25° C, 3000K and can be driven to a maximum current of 60mA delivering upto 155 lumens to address high-lumen applications that require low cost and high reliability solutions. To improve time-to-market, lighting manufacturers seeking ENERGY STAR qualification can take advantage of the completed 6,000 hours LM-80 data of the Acrich MJT 3030 LED.

Utilizing Seoul Semiconductor’s proven and reliable high voltage architecture, Acrich MJT “Multi-Junction chip Technology”, the Acrich LED eliminates the tradeoff between size and efficacy. The Acrich MJT 3030 can be operated in either AC or DC modes, depending on your configuration. AC mode, which uses the Acrich IC instead of an AC/DC converter, improves reliability and simplifies integration when making lighting fixtures. The 0.97 power factor and low THD of Acrich IC-based modules helps save energy and optimize designs. In the DC-mode, the low-current operation of the Acrich MJT 3030 can lower the number of components and reduce the cost of the power supply. The inherent flexibility of the Acrich MJT 3030 LED enables optimized performance in both AC and DC configurations.

Seoul Semiconductor Executive Vice President of Lighting sales, Jay Kim stated that, “The new Acrich MJT 3030 LED combines the improved performance and high lm/$ with the reliability of the MJT technology enabling lighting manufacturers to create new innovative solutions to address a wide range of lighting applications.”

Last month, Yole Développement  announced the update of its technology and market analysis, LED Packaging Technology & Market Trends. Under this new report, the research market and strategy consulting company highlights the impact of advanced packaging technologies in the LED industry.

“The combination of cost reduction and advanced packaging technologies such as Flip Chip and Chip Scale Package, is changing the LED industry landscape, especially its supply chain,” Yole announced.  For example, introduction of Chip Scale Package solution clearly reduces the number of manufacturing steps: today, some LED chip manufacturers, with Chip Scale Package technology already supply their products to the LED module makers directly.

LED packaging

Flip Chip technology has step by step attracted attention from the lighting, backlighting and flash markets, becoming one the most important developing items this year. Following the LED TV crisis and with the entry of Chinese players, positioning has been reshuffled in the LED industry. The product quality of Chinese LED manufacturers has increased to a level where they are now real competitors for all players. In such a highly competitive environment, three major challenges lie ahead for the LED industry regarding the General Lighting market: efficacy improvement, cost decrease and color consistency increase.

To answer these challenges, several players have now turned to Flip Chip (FC) LED, as these components present several advantages over traditional horizontal (MESA) and vertical LEDs: they are wire-bonding free, can be driven at higher current, and have a smaller size package (…).

And although the FC LED technology has been launched for quite a long time by Lumileds, it was restricted from “popularization” due to technical / technological barriers (low yield regarding bumping / eutectic process…). Additionally, the financial investment required for packaging equipment, represented a strong barrier in an industry that was still recovering.

At middle and long term, this technology [CSP] could make chip manufacturers supply directly to module manufacturers.

But the technology has gradually attracted attention from the lighting, backlighting and flash markets, becoming one the most important developing items this year.

“Whereas Flip Chip LED represented only 11 percent of overall high power LED packaging in 2013, we expect this component to represent 34 percent by 2020. Flip Chip LED will take market share from vertical LED that will represent 27 percent of overall high power LED packages by 2020,” said Pars Mukish, Senior Market & Technology Analyst, LED, Lighting Technologies, Compound Semiconductors and OLEDs.

In addition to offering an increased “performance / cost” ratio, Flip Chip LEDs are also a key enabling technology for the development of Chip Scale Package (CSP) that could allow for further cost reduction.

CSPs are novel to the LED industry but they are the mainstay of the semiconductor industry. Development of CSPs in the Silicon ICs was driven by miniaturization, improved thermal management, higher reliability, and simply the need to connect to an ever increasing pin-count on an ever shrinking die. Chip Scale packages also enabled a reduction in device parasitic and allowed for ease of integration into Level 2 packaging (e.g.: module packaging for LED). It is therefore a natural evolution for this packaging innovation to proliferate into other industries (such as the LED industry).
Basically, a CSP represents a single chip direct mountable package that is the same size as the chip. Regarding LED devices, CSPs are made of a blue FC LED die on which a phosphor layer is coated (the main application of such package being General Lighting). CSP presents several advantages such as: miniaturized size, better thermal contact to substrate. However, eliminating several process steps of traditional LED packaging, CSPs are also having an impact on the industry structure with some LED chip manufacturers supplying their products directly to LED module manufacturers. At middle and long term, this technology could make chip manufacturers supply directly to module manufacturers.

Soraa, a developer of GaN on GaN LED technology, announced today that one of its founders, Dr. Shuji Nakamura, has been awarded the 2014 Nobel Prize in Physics. Recognizing that Nakamura’s invention, the blue light emitting diode (LED), represents a critical advancement in LED lighting, the Nobel committee explained the innovation “has enabled bright and energy-saving white light sources.”

“I am very honored to receive the Nobel Prize from The Royal Swedish Academy of Science for my invention of the blue LED,” said Nakamura. “It is very satisfying to see that my dream of LED lighting has become a reality. I hope that energy-efficient LED light bulbs will help reduce energy use and lower the cost of lighting worldwide, and that is why we founded Soraa.”

Shuji Nakamura - SoraaIn 2007, Dr. Shuji Nakamura, along with pioneering professors Dr. Steven DenBaars and Dr. James Speck, came together and made a bet on an LED technology platform completely different than current industry practice, a technology most industry experts at the time considered to be impossible to execute.

“We knew that our GaN on GaN LED technology would be the future of lighting and Soraa has made this a reality,” added Nakamura.

Soraa bet that GaN on GaN LEDs would produce more light per area of LED and be more cost-effective than technology based on other foreign substrates like sapphire or silicon carbide. This strategy ran against every trend in the LED industry. That bet paid off: today, Soraa’s LEDs emit more light per LED material than any other LED; handle more electric current per area than any other LED; and its GaN on GaN crystals are up to a thousand times purer than any other LED crystal.

“Shuji is simply brilliant and well deserving of this honor. Largely as a result of his work, Soraa has been able to push the boundaries of what is possible in high performance LED lighting,” said Jeff Parker, CEO of Soraa. “Soraa’s GaN on GaN LED lamps are now regarded as the best in the world, with quality of light that far surpasses any other LED product.”

Pixelligent Technologies announced today that it has been selected for a Department of Energy (DOE) solid-state-lighting award to support the continued development of its OLED lighting application. The details of the award can be viewed on the DOE SSL website. Pixelligent and its partner OLEDWorks were selected as one of only nine awardees nationwide for this $1.25 million DOE award.

“This is the second OLED lighting award we have received from the DOE in partnership with OLEDWorks, which clearly demonstrates our leadership position in developing the next generation materials required to accelerate the commercialization of OLED lighting,” said Craig Bandes, President & CEO of Pixelligent Technologies.  “We are proud to have been selected by the DOE for this highly competitive grant that, when combined with our internal investments, will provide the resources required to optimize our OLED lighting application,” said Gregory Cooper PhD, Founder & CTO of Pixelligent Technologies.

The goal of this project is to develop a novel internal light extraction design that improves the light extraction efficiency of OLED lighting devices by more than 200%, without negatively impacting the device voltage, efficacy, or angular color dependence.

“This federal grant reflects the type of common sense investments we should be making to help our economy rebound by boosting U.S. manufacturing and high-tech innovation,” said Congressman Ruppersberger of Maryland’s Second District. “The fact that one of Baltimore’s own companies was selected and will be bringing jobs back to the city is icing on the cake. Pixelligent is an impressive and growing company, and I am proud that they have chosen the Second District to call home.”

In the LED packaging world, a wind of change is blowing. A LED TV crisis, and new Chinese players have totally modified the LED industry and its supply chain. Under this context, with a high competitive environment, new challenges have been identified by Yole Développement (Yole) analysts: efficacy improvement, cost decrease. To answer to the LED market needs, companies have today to innovate their technologies and implement new solutions like Flip Chip for LED packaging.

highpowerled_breakdown_yole_sept.2014

“In 2013, LED based on Flip Chip technology represented 11 percent (in volume) of the overall high power LED market; such market share should reach 24 percent (in volume as well) by 2020”, explains Pars Mukish, Senior Market and Technology Analyst, LED, OLED & Compound Semiconductors, at Yole (Source: LED Packaging 2014 report, to be released end of September 2014).

At the end of September, the 4th International LED professional Symposium +Expo (LpS 2014) will take place for the second time. Located in Bregenz, Austria and targeting industrials and researchers involved in LED design and engineering, the symposium is a three-day event including conferences, workshops, networking and exhibition.

At LpS 2014, Yole will present its latest analysis, with a special focus on LED chip manufacturing and packaging. During his presentation, Pars Mukish from Yole, will highlight the recent developments dedicated to LED chip manufacturing and packaging. Yole’s analyst will detail main market trends, emerging technologies and technical challenges including packaging process steps and supply chain.

All these results are part of two technology & market reports, LED Front-End Manufacturing Trends (released in May 2014) and LED Packaging that will be released end of September 2014.

“At Yole, we are daily working with the key players of the LED industry, to understand and analyze recent developments on manufacturing process and packaging solutions. Our objective is to evaluate the impact of the LED penetration rate in the solid state lighting market,” explains Pars Mukish.

LpS 2014 is a 60-lecture program and welcomes 1,300 visitors.