Category Archives: LED Manufacturing

October 31, 2011 — Georgia Institute of Technology (Georgia Tech) researchers have found that gallium nitride (GaN) light emitting diodes (LEDs) get a significant efficiency boost from zinc oxide (ZnO) microwires. The piezo-phototronic effect charges LEDs’ ability to convert electricity to ultraviolet (UV) light, which GA Tech believes is a first for the LED industry.

Piezo-phototronics is the control of an optoelectronic device with piezoelectric potential. In this study, the ZnO crystals become electrically charged when its polarized ions are compressed or otherwise mechanically strained. Georgia Tech notes that piezoelectric and semiconducting materials can be tuned mechanically, opening up various device design improvement opportunities.

Mechanical strain brought out the piezoelectric potential in the wires, which then allowed researchers to tune the charge transport at the p-n junction and enhance carrier injection in the LEDs. The rate at which electrons and holes recombined to generate photons increased.

October 25, 2011 — Strategies in Light, an annual tradeshow on high-brightness LEDs and lighting hosted by Strategies Unlimited and PennWell Corporation, will take place February 7-9, 2012 in Santa Clara, CA. New this year, the conference will include a full parallel track on LED manufacturing.

SIL 2011 hosted a half-day track on LED manufacturing, and attendees called for more information on the topic at SIL 2012. The HB LED industry is heading increasingly into high-volume manufacturing (HVM), bringing increased attention to fabrication issues and trends. LED equipment suppliers and traditional semiconductor tool makers are serving the LED industry. The trend is to move LEDs to larger wafer sizes for better economies of scale. Concurrent trends are pushing increased automation and improved yield and throughput. The LED Manufacturing Track is sponsored by SEMI.

The HB-LED market grew 108% in 2010, driven in large part by LED backlighting in LCDs (TVs, computers and laptops) and causing widespread industry scale-up. 2011 growth is forecast to be 10%, as LCD TV demand slows and an LED oversupply suppresses prices. Nevertheless, the HB LED market is forecast to grow another 45% by 2014 to $16.2 billion, driven by recovery in the backlight market and by the continuing adoption of LED lighting. The LED market is

October 25, 2011 – Marketwire — Bridgelux Inc., LED lighting developer and manufacturer, closed an additional $15 million in financing. The funds were needed to accelerate R&D and scaling of Bridgelux’s gallium nitride on silicon (GaN-on-Si) light-emitting diode (LED) chip technologies.

The oversubscribed financing round included existing financial and strategic investors: VantagePoint Capital Partners, DCM, El Dorado Ventures, Novus Energy Partners, IFA, Chrysalix, Harris & Harris Group, Craton Equity Partners, Jebsen Asset Management, and Passport Capital, among others. The company’s prior fundraising (series D) hit $50 million.

The goal is commercial-grade LEDs on silicon, commercialized in 2013, developed alongside Bridgelux’s GaN-on-sapphire arrays, said Bill Watkins, Bridgelux CEO. Bridgelux reported a new Lumens/W company record for Gan-on-Si LEDs in August 2011, claiming sapphire-like results.

The cost-reducing silicon-based technology could help the company take a larger market share of solid-state general lighting, which could grow from $3 billion in 2011 to more than $25 billion in 2015, Watkins said.

Bridgelux develops and manufactures solid state lighting (SSL). For more information about the company, please visit www.bridgelux.com.

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October 21, 2011 — Sapphire substrate maker Rubicon Technology Inc. (NASDAQ:RBCN) will transition to on-premise aluminum oxide processing to better control the quality of its sapphire wafers, and reduce manufacturing expenses while ensuring a steady supply of raw materials.

Rubicon’s customized in-house method converts raw aluminum oxide powder so it can be used in the Rubicon ES2 crystal growth process. The powder is formed into various shapes to optimize crucible space, enabling growth of larger crystals.

Large-diameter wafer transitions are occuring around the light-emitting diode (LED) industry, noted Raja Parvez, Rubicon president and CEO, who explained that the larger wafers can be as much as 3x thicker than 2" to 4" wafers, requiring more aluminum oxide. To date, Rubicon has successfully shipped more than 150,000 6" sapphire wafers.  

Advances in raw material handling combined with recent company-wide installation of enhancements to its proprietary crystal growth furnaces, Rubicon Furnace Version ES2-XLG3.0, delivers cost efficiencies for the production of large diameter sapphire. Rubicon

October 14, 2011 — Optogan opened its light-emitting diode (LED) production site in Landshut, Germany, bringing "future-oriented" industry to Bavaria, said the Minister of Economic Affairs of the German Federal State of Bavaria, Martin Zeil, who spoke at the opening.

Optogan expanded in Germany with the new site, located near to Munich Airport. A former Hitachi semiconductor fab, the site boasts a 4000m2 cleanroom. Up to 100 workers will staff the site. Initial capacity will exceed 1 billion chips/year. The site will be Optogan’s hub of international business, which is expanding from Europe to a global scale, explains Hans Peter Ehweiner, managing director of Optogan GmbH.

The Landshut LEDs will be used for lamps and luminaires in indoor, outdoor, and residential applications.

The Optogan Group develops and manufactures state-of-the-art chip technologies. Learn more at www.optogan.com.

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October 13, 2011 — Researchers from the Samsung Advanced Institute of Technology (SAIT) and the University of Cambridge created a full-color high-resolution 4" quantum dot light emitting diode (QD-LED) display using transfer printing (Nature Photonics, 2011).

Figure. Transfer printing for patterning quantum dots (QDs). (i) Modification of the donor surface with SAM, and spin-coating of QDs. (ii) Application of an elastomer stamp to the QD film with appropriate pressure. (iii) Peeling of the stamp, quickly, from the donor substrate. (iv) Contacting the inked stamp to the device stack, and slowly peeling back the stamp. (v)–(vii) Sequential transfer printing of green and blue QDs. b, Fluorescence micrograph of the transfer-printed RGB QD stripes onto the glass substrate, excited by 365 nm UV radiation.

The team began by modifying the donor substrate surface with a chemically bound self-assembled monolayer (SAM). Red-, green-, and blue-emissive quantum dots are printed via the same precise process at room temperature. Various substrates could be used, including flexible ITO/PEN. Future work will focus on scaling the printing process to industrial production without degrading resolution. Aligning the different color QD stripes over large-area may pose a challenge, notes Khashayar Ghaffarzadeh, technology analyst, IDTechEx.
 
QD-LEDs are electroluminescent colloidal quantum dots that can be printed in thin films to combine inorganic LEDs’ customizable, saturated, stable color and low-voltage performance with polymers’ solution processability, said Ghaffarzadeh.

Also read: Quantum dot OLEDs fabbed via spin coating

For QD-LEDs to work, the thin film transistors (TFTs) in the active-matrix backplane must supply a very stable current. New backplane technologies like metal oxides could replace amorphous silicon for this function. Researchers from the University of Cambridge have also demonstrated solution-processed high-performance metal-oxide TFTs (Nature Materials, 2011) with a <250°C annealing temperature.

The University of Cambridge will present at IDTechEx’s Printed Electronics USA. Printed Electronics USA 2011 will take place November 29-December 2 in Santa Clara, CA, with tours to local centers of excellence. Learn more at www.IDTechEx.com/peUSA.

References:
Full-colour quantum dot displays fabricated by transfer printing, Nature Photonics 5, 176-182, (2011). Low-temperature, high-performance solution-processed metal oxide thin-film transistors formed by a ‘sol-gel on chip’ process, Nature Materials 10, 45-50(2011).

IDTechEx provides custom consulting, research and advisory services in Printed Electronics, RFID, Photovoltaics, Energy Harvesting and Electric Vehicles. Learn more at www.IDTechEx.com/nano.

October 12, 2011 — SEMI’s annual semiconductor silicon shipment forecast provides an outlook for silicon demand for 2011-2013.

SEMI recorded that polished and epitaxial silicon shipments will hit 9,131 million square inches (MSI) in 2011, 9,529 MSI in 2012, and 9,995 MSI in 2013 (table). Silicon wafers are the basis of virtually all semiconductors and MEMS, and epi-wafers are the basis of products like LEDs.

While the market has currently softened, early-2011 momentum will carry the year’s semiconductor silicon sales to a higher total than 2010, said Stanley T. Myers, president and CEO of SEMI, noting the figures are an industry record. Growth will continue at "modest levels" through 2013.

Table. 2011 silicon forecast, total Si slices excluding non-polished. SOURCE: SEMI, October 2011.
  2009 2010 2011 2012 2013
Millions of square inches (MSI) 6,554 9,121 9,131 9,529 9,995
Annual growth (%)  -17 39 0 4 5

Also read SEMI’s report from August 2011, Silicon wafer shipments ride out Japan disaster

The data are inclusive of polished silicon wafers, including virgin test wafers, and epitaxial silicon wafers shipped by wafer manufacturers to semiconductor end-users.

SEMI is a global industry association serving the nano- and microelectronic manufacturing supply chains. For more information, visit www.semi.org.

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October 7, 2011 — Revenues for high-brightness light emitting diodes (HB-LEDs) grew 108% to $11.2 billion in 2010, driven by applications in TV backlight units, according to a new market report by Strategies Unlimited. The party is quieting down though, as expanding supply and a slowdown in overall TV demand in 2011 pushed LED prices drastically lower.

Strategies Unlimited revised down its 2011 HB-LED revenue estimate to $12.3 billion. LED prices plummeted 20-40% recently, except for certain specialized applications. This industry correction will take weaker and/or newer LED manufacturers out of the market. Look for consolidation in China. Strong manufacturers with deep pockets to survive fluctuations will survive, Strategies Unlimited reports.

Revenue will peak in 2014, hitting $16.2 billion, before dropping off to $15.3 billion the next year. Once lighting takes over as the growth driver for HB-LED adoption, predicted to occur in 2015, revenues will again increase.

The LED price drop could lead to higher LED adoption, particularly in lighting, where ELDs are about 30% of the bill of materials (BOM). Strategies Unlimited reports that high-quality, large-volume 1W cool white packaged LEDs with delivery in September 2011 are being quoted around $0.65.

In other application sectors, LED revenues for signs were $1.1B in 2010, growing to about $1.6B in 2015. Signage overall will grow at 14% CAGR through 2015, with the vast majority coming from Chinese manufacturers.

LEDs for mobile devices — smartphones, tablet computers, notebooks — will experience declining revenues 2010-2015, despite fast-growing device adoption. Here, price suppression will help bring LED revenues down -4.1% compounded annually.

Figure. HB-LED market by revenue and year-over-year (YoY) growth rate 2010-2015. SOURCE: Strategies Unlimited.

Automotive applications brought in $1.1 billion in LED revenues for 2010, thanks to China-based growth. As China cools off in 2011 and the Japan tsunami disrupted supply chains, 2011 will see only 5% growth in this sector. Increased use of LEDs in daytime running lights and headlamps will fuel revenue growth for LEDs in exterior automotive lighting at 10%, compounded annually.  Falling prices and saturation of LEDs in instrument panels — reaching 90% in 2015 — will erode LED revenue for that segment by 2% over the period.

Strategies Unlimited released

September 27, 2011 — The US Department of Energy (DOE) is accepting funding applications through December 15, 2011, for developers of energy-saving lighting technologies. The Obama Administration authorized up to $10 million for manufacturing research and development on solid-state lighting (SSL), such as light-emitting diodes (LEDs) and organic LEDs (OLEDs).

The DOE expects solid-state lighting, which can be more than 10x more efficient than incandescent lighting, to reduce the amount of electricity used for US lighting by one fourth by 2030. This would save $15 billion and be the greenhouse gas emissions reduction equivalent of 21 million cars.

Applicants should focus on reducing the cost of LEDs/OLEDs through better manufacturing equipment, processes, and process control. Between 2 and 4 project awards will be granted. These will address the technical challenges facing SSL in the mainstream lighting market, particularly considering cost.

This is the third round of funding directed toward this solid-state lighting research and development program area. Over the course of the program, the Manufacturing Research and Development area has been funded with $28.2 million in federal funding, and leveraged $36.8 million in funding from the private sector.

To apply or for more information, see DOE

September 27, 2011 — Pixelligent LLC, nanocrystal additive maker, closed $5.1 million in funding. The round was 6 times over-subscribed, requiring the company board to significantly upsize the round.

Pixelligent will purchase production equipment, install new systems and hire employees. It will provide the resources for Pixelligent to bring NanoAdditives to a broader market, said Craig Bandies, CEO Pixelligent Technologies.

New investors included the Abell Foundation, WISE LLC, and an Angel group. The Baltimore Development Corporation (BDC) and the Maryland Department of Business and Economic Development (DBED) added funds, $200,000 and $100,000 respectively. Pixelligent has raised nearly $9M in equity and has been awarded more than $9M in government grant programs during the past 30 months.

Pixelligent "demonstrated tremendous progress" over 24 months, said Robert Embry, president of the Abell Foundation. The nanotechnology products address critical challenges in electronics, industrial, and lubricants sectors, added Lisa Gordon-Hagerty of WISE LLC.

Pixelligent recently moved into a new 10,500sq.ft. pilot manufacturing facility in Baltimore, MD. The facility has room for expansion, and Pixelligent is recruiting senior manufacturing, sales, and finance staff. The facility will open in Fall 2011.

Pixelligent Technologies supplies nanocrystal additives for the electronics, industrial and military markets. Learn more at www.pixelligent.com.