Category Archives: LEDs

Jan. 9, 2007 – After a five-month search, fabless firm Xilinx has hired Moshe Gavrielov, former EVP/GM of Cadence Design Systems’ verification division, as its next president/CEO effective immediately, taking over for the retiring Willem Roelandts, who will remain chairman of the board.

Gavrielov brings nearly 30 years’ experience in semiconductor and software engineering and executive roles, most recently at Cadence, whom he joined through a 2005 acquisition of Verisity. Before that he spent nearly 10 years at LSI Logic including EVP of its $1.3B products group, SVP/GM of international markets, and GM of its ASIC division. He started his career at National Semiconductor and Digital Equipment.

“Moshe has an excellent track record in building semiconductor and software businesses, applying an outstanding blend of strategic, analytic, business and leadership skills,” said Roelandts, in a statement. “We’re fully confident that he is the right person to lead Xilinx through its next stage of growth.

“We have a great opportunity to bring the benefits of Xilinx technology to a broader range of industries and applications in the coming years, building upon a solid foundation of technology innovation and market leadership,” stated Gavrielov.

Since Roelandts took the company’s reins in 2006 (he formerly led HP’s $6B global computer systems biz), revenues have nearly quadrupled, with global business expanding and diversifying into high-growth end markets — e.g., consumer, automotive, industrial, and defense have grown from 12% of revenues in 2002 to 45% in 2007, the company noted. Xilinx ranked No.8 in global fabless revenues in 2Q07 with $443M, and No.7 overall in 2006 ($1.9B), according to the Global Semiconductor Association (nee FSA).

by Bob Haavind, Editorial Director, Solid State Technology

There were many novel device concepts explored at the recent 2007 International Electron Devices Meeting (IEDM) in Washington DC. While several papers discussed high-k/metal gate dielectric concepts to cut leakage currents, there was also some discussion of performance enhancement by using metal for the source and drain. A novel source/drain implant technique enabling very low leakage silicon-on-insulator (SOI) CMOS for 65nm and below was reported by IBM. A new concept for optoelectronic tweezers that can trap and move objects down to the nanoscale was described by Ming Wu of the U. of California at Berkeley.

Performance enhancement using metal source/drain was explored in two IEDM papers. Metal could potentially offer less S/D contact resistance, but the problem is high-contact resistance at the source/channel interface due to a Schottky barrier. Larrieu et al. from IEMN-UMR CNRS, STMicroelectronics, and UCL in France, showed how a low-temperature (<500°C) activation could be used for boron doping of PtSi source/drain in an implantation through silicide process that improved drive current by 50% compared to a dopant-free approach for thin-body SOI MOSFETs.

A Toshiba group showed how sputtering yttrium, ytterbium, and platinum onto an NiSi source and drain, and then annealing them to segregate the metals at the NiSi/Si interface can achieve 0.1-1.5eV Schottky barrier reduction for both nMOS and pMOS. The process is reported to be thermally stable and scalable, offering improved contact resistance for future metal S/D CMOS.

A number of junction engineering techniques were investigated by IBM research groups to lower leakage current for partially depleted, low-power SOI CMOS devices down to 10μmA/μm with a 1.2V supply voltage. These included low damage junction preamorphization implants, a high-energy halo, and drain-side tilted source/drain implants. The key advance in the work is a novel method to tie the body to the source of SOI devices without modifying the device layout. Tilted S/D implants from the drain side move the deep source region away from the gate edge and expose the body under the source-side extension for salicide (see figure). This internal source-body tie was achieved in both nFET and pFET by using suitable tilt angle and extension conditions. Both the subthreshold slope and drain induced barrier loading (DIBL) were improved, although there was some increase in channel resistance resulting in a penalty of about 5% in IDSAT.

Drain-sided tilted deep S/D implants in an SOI CMOS FET enable silicidization of part of the body near the source to tie the body to the source. (Source: IBM, IEDM)

Optoelectronic tweezers that could trap and move colloidal particles with diameters down to tens of nanometers were developed at the U. of California at Berkeley. The technique combines the advantages of optical tweezers and dielectrophoresis, but uses 100,000 times less power than optical tweezers, according to Ming Wu. Instead of handwired electrodes, the technique uses a projected light pattern on a photoconductive surface to create “virtual electrodes.” Since coherent light is not needed, low-cost sources such as a lamp or LEDs can be used instead of a laser. Light patterns are generated by a digital micromirror device are imaged onto the photoconductive surface, turning it into a programmable virtual electrode for DEP.

Wu reported that the technique has been used to trap single semiconductor nanowires, and also to manipulate cells in cell-culture media. — B.H.

Jan. 4, 2008 – JP Sercel Associates says it has been awarded a patent in Korea for its front-side laser scribing technique for LED wafers, which uses a unique laser energy distribution technique to allow extremely narrow kerf widths (2.5μm wide), resulting in faster processing, higher yields, and more die/wafer.

Using this technology, the company’s IX-200 Chromadice DPSS UV laser wafer singulation system can process 15 2-in. wafers/hr, “a dramatic increase in throughput compared to diamond scribing and conventional laser techniques,” according to company president Jeffrey Sercel.

Braggone’s proprietary material technology allows for custom tuning of the inorganic-organic polymer material properties to suit specific applications. These flexible yet stable materials coat or print onto substrates at greater efficiency, lower temperatures and higher yields. The company’s current materials products are applied in digital displays used in mobile phones and televisions, advanced semiconductors, digital cameras, photovoltaic panels, LEDs and memory for PCs and MP3 devices.

(January 4, 2008) TOKYO, JAPAN — Electro Scientific Industries Inc., a provider of photonic and laser systems for micro-engineering applications, has announced that it will directly represent its memory repair products in Japan and separate from Canon Marketing Japan Inc., its distributor.

BY JAN PROVOOST, IMEC

Although most electronic appliances are rigid, or at most mechanically flexible, future applications will require them to be flexible, stretchable, and offer maximum user comfort. Developments at one lab* resulted in the creation of elastic interconnections that stretch to twice their length without losing conductivity.

Lab researchers embedded interconnection wires with a 2D undulating pattern in an elastic silicone film. The 2D springs were designed and optimized in cooperation with a group of specialists** in mechanical modeling and reliability prediction. The researchers inferred, based on finite element analysis, that an undulating horseshoe shape is the ideal form for the connection wires. It dissipates the stretching and flexing stresses better than comparable elliptical patterns. Second, they further improved the stress resistance of the interconnections by splitting each interconnection wire into four parallel wires with a smaller width. Initially, gold was selected as a material for the wires, because of its high ductility, which allows for greater stress resistance.

The resulting interconnection wires consist of four parallel tracks, each 15 μm wide, made of a 4-μm-thick gold layer and coated with a 2-μm-thick nickel layer for soldering to components. At regular intervals, in positions where the deformation stress is calculated to be minimal, neighboring tracks are cross-connected. This allows for fail-safe operation in case of fabrication errors or mechanical failure.

The interconnection wires are embedded in a silicone polymer substrate: polydimethylsiloxane (PDMS). By itself, PDMS is an electrical insulator, but becomes conductive when, for example, silver particles are added. This modified polymer can carry a signal over short distances. Should a wire be overstretched, resulting in a microcrack, the surrounding polymer will still conduct the signal, bridging the gap.

The researchers made interconnections with different angles and radii for the horseshoe shape. circuits were tested by stretching them in the longitudinal direction to the point of electrical failure, which a rupture in the gold tracks could cause. The best interconnection stretched from 3-6 cms without failure. Moreover, all interconnections recovered their conductivity when returned to their normal length.


Figure 1. Stretchable LED-circuit embedded in PDMS, fixed on textile, and washed repeatedly in a standard washing machine.
Click here to enlarge image

To assemble the stretchable interconnections and the more rigid electronic components, joints were soldered using normal electronics assembly methods. Next, the silicone polymer was molded around the assembly, taking care not to cause any bubbles in the silicone. For each design, a dedicated mold is made. This mold takes into account the locations on the assembly where the rigid parts are located. At these locations, the silicone wrapping should be thicker so that the circuitry is locally less stretchable.

The researchers now also study the use of conducting materials other than gold, such as copper, the standard material in PCB manufacturing. Wiring with copper is more cost-effective than with gold. But the main reason is the drive to develop a technology that is compatible with existing industrial PCB and assembly practices to facilitate the technology’s transfer to a production environment.

Ongoing research projects aim to create flexible and stretchable electronic and sensor circuits. Real-life stretchable appliances will be hybrid, and will contain rigid or flexible components connected with stretchable circuitry. The circuitry will stretch and bend like rubber or skin while preserving its conductivity. The goal is to combine this stretchable interconnection technology with flexible circuit technologies, as developed in the EC-SHIFT project. An example is the ultra-thin chip package, or UTCP, which is only 100-μm thick.

Within 3 years, and based on current research results, a technology and demonstrator will be ready for commercialization. The first flexible and stretchable appliances might appear in intelligent clothing, followed by medical applications. The circuits will also be washable, which is a big step forward for intelligent clothing. First commercial products might be clothing with signalization, using LEDs and sensors, to track movements.

*The TFCG Microsystems lab, associated with the IMEC research center.
**IMEC IPSI/REMO Group

Jan Provoost, scientific editor at IMEC may be contacted at IMEC, Kapeldreef 75, Leuven, Belgium, B-3001; phone: +32/16-28143; E-mail: [email protected].

December 21, 2007 – Taiwan’s top display panel supplier AU Optronics is reportedly venturing into production of epitaxy for LEDs with a new subsidiary, gaining a foothold in a market seen as key for displays, according to local reports.

The Taiwan Economic News says that the company has already started procuring equipment for the new unit in Hsinchu, northern Taiwan, with total planned investments of >$300M. Digitimes, citing a report by Chinese-language Economic Daily News, claims the firm will buy up to 100 MOCVD tools, but has not yet laid out a production manufacturing timeline.

Among local suppliers, Epistar has the largest capacity of LED epitaxy, with ~150 MOCVD tools at its disposal; AU and Chi Mei Optoelectronics, which has deployed LED operations through an affiliate, are producing LEDs on a trial basis.

But with the projected importance of LEDs as backlighting for notebook displays and eventually LCD TVs, AU and CMO are moving to boost their investments in the field and hopefully avoid future LED chip shortages. That could impact upstream LED epitaxy suppliers including Epistar, Formosa Epitaxy, Huga Optotech, Arima Optoelectronics, and Uni Light Technology, the paper notes.

December 21, 2007 – Tong Hsing Electronic Industries, based in Taiwan, said that it plans to extend its foothold into niche markets in 2008 and predicted that LED substrates and MEMS devices for projectors and the automotive sector will drive annual sales growth by more than 20 percent.

The combined sales contribution of products for niche applications, including high-frequency wireless and mixed-signal circuitry modules, already reached 80 percent in 2006, the company said. It predicts sales to hit $115 million in 2008.

December 20, 2007 – Matsushita Electric Industrial Co., Canon Inc., and Hitachi Ltd. are in talks to form a partnership for organic electroluminescence (OEL) flat panels, likely involving hundreds of billions of yen to establish minority stakes in Hitachi’s display subsidiary, according to local media reports.

Under the deal, reported by the Nikkei daily, Matsushita and Canon would invest more than 100B yen (US ~$883M) from both Matsushita and Canon in the unit, which makes small and midsize LED panels in addition to OEL panels. Hitachi would retain just over a 50% interest. Matsushita has interest in the OEL panels for TVs, while Canon wants them for digital still/video cameras.

Matsushita reportedly also wants to increase to a majority stake in IPS Alpha Technology Ltd., a large-panel LCD production JV currently involving Hitachi Displays (50%), Matsushita (32%), and Toshiba (16%), and would increase current output capacity of 5M panels/year with a ~300B yen ($2.65B) 8G factory.

The company’s plans to increase its LCD interests roughly shift Japan’s LCD panel industry into three groups: the Matsushita-led alliance, Sharp, and Sony/Samsung. Perhaps most importantly, the deals give Matsushita direct access to production facilities — as it had been relying on partners for the LCD panels, it could not secure enough panels when supplies grew tight to achieve its LCD TV sales targets, notes the Nikkei daily, something solved by taking over control of IPS and building a new LCD plant.

In a larger scheme, the deals are likely to boost Japan’s presence in LCD manufacturing, and make the more competitive against Korean and Taiwanese rivals — so said Sharp CEO Katsuhiko Machida, quoted by Dow Jones.

CPT’s move is not a surprise to the local TFT-LCD industry, as most major players have begun deployments in the LED business.

(December 18, 2007) EINDHOVEN, The Netherlands — The Dutch rollable display company Polymer Vision has joined the Holst Centre, an initiative of the Flemish and Dutch research centers IMEC and TNO. During the partnership, Polymer Vision will research and develop organic transistor technology and patterning processes in the open-innovation setting of Holst Centre, collaborating with other researchers from other companies joining the program. Polymer Vision and Holst Centre are both located on the High-Tech Campus in Eindhoven.

These new orders consist of one new customer and a follow-on order from an existing customer, both based in the Asia-Pacific market. Amtech expects the $8.9 million in orders to ship in fiscal 2008, which began October 1, 2007. Since October 1, 2007, Amtech has received solar orders totaling approximately $27.8 million.

(December 17, 2007) TAIPEI, Taiwan — In line with the increasing use of LED backlight modules in display applications, Chunghwa Picture Tubes Ltd. (CPT) reportedly plans to step into upstream LED manufacturing, according to industry sources, reported CENS. CPT reportedly plans to have its affiliated Sintronic Technology Inc. take charge of LED packaging, and San Chih Semiconductor Co., Ltd. will be responsible for LED epitaxy.