[Happy Birthday, Martin Luther King, Jr.!]

SMC highlights PV, LED, and packaging materials
Last week saw hundreds of microelectronics industry executives gather at ISS and SMC. The conventional forecasts for semiconductor manufacturing equipment and materials have been covered by previous WaferNEWS stories. SMC showed truly amazing perspective on new electronic materials markets of gigantic scales like photo-voltaics, high-efficiency lighting, and advanced 3D and WLP packages.

Solar is hotter than the sun these days, and Craig Hunter of Applied Materials provided a great overview of the whole market and his company’s leading position in offering turn-key fabs. The photo shows an Applied Materials’ SunFab PECVD 5.7 and those really are full size people standing next to a multi-chamber deposition system for PV on huge glass panels.

The global market in 2007 for PV panels was reportedly 4.8 GW, up ~50% from 2006. The current approximate cost to install a rooftop solar PV system is US$0.25-0.30/kWhr (absent incentives). However, nearly all PV manufacturers show near-term roadmaps to cut PV fab costs in half, and there are additional innovations possible in installation of modules, so it seems likely that price could drop to US$0.10-0.12/kWhr for large scale installations without any incentives. With demand forecasted to be extremely elastic to price, and with total global energy use growing at 2%/year on the scale of TeraWatts, PV will likely remain <1%>

The future of mega-fabs for PV panels includes integrated supply-chain campuses like the classic old Ford Rouge Plant in the 1920s. The thin-film PV fab of the future will be more efficient when if has a dedicated float glass plant for the substrate, a line for the thin-film encapsulant formation, and even packaging of the junction-boxes for the final modules. Each of these may be owned by a different company, but for economies of scale and manufacturing efficiency they’ll be adjacent to each other. Process gases such as hydrogen, silane, etc. account for ~17% of final panel costs, so long-considered innovations such as silane reclamation make be used in manufacturing In general it seems that the main scientific breakthroughs in PV have been made, and now the best engineers will win the race to fab profits. “People ask me all the time where I would locate a PV fab if I had to chose,” opined Hunter. “I think there’s a big opportunity for someone to put a factory in New Mexico, Arizona, or Texas.”

George Craford, CTO of Philips Lumileds Lighting Company, discussed the immanent “Revolution in lighting, high power LED technology.” As a demonstration, Buckingham Palace has been externally lit by LEDs at a cost of US$0.45/hr. The theoretical light output limit for an LED is 300 lumens/Watt, but the best in production is ~100 lumens/W, with 150 lumens/W on a roadmap. The plan is for high-power LEDs to be 1-3 per replacement bulb.

From the 1960s through the 1990s the LED brightness evolved at a fairly constant rate, though this was based on driving the same size chips with the same power. Starting ~10 years ago, the industry began to work with new packages to allow driving higher current-densities and resulting higher outputs for applications include automotive, flashlights, and projectors.

Why aren’t white LEDs everywhere? Quite simply the cost has been too high. For the same 1000 lumens output (60-100W incandescent bulb equivalent) the indandescent bulb costs $0.40, fluorescent tube $0.60, compact fluorescent $2, and white LED $10. Lumileds researchers seem confident that they can improve the basic Internal Quantum Efficiency (IQE) from ~45% today to ~90% tomorrow, and with higher drive current (700 mA to 2A) and lower chip and packaging costs the cost could be ~$1.

The energy savings with LEDs is truly impressive:

1000 lumens Input Power Energy cost/yr COO for 5 yrs
Incandescent 60W $48 $240
Fluorescent 20W $18 $90
Comp.Fluor. 14W $13 $85
White LED 6W $5 $26

Control of manufacturing is a concern since the variation in blue wavelength crossed with the yellow phosphor materials distribution creates variation in the color of white. The human eye is sensitive to subtle color variations and tight matching is needed for LEDs in the same room. Off-grid applications can be valuable using a single LED with a solar array or a bicycle generator…for example Light Up The World foundation has been installing LEDs around the world to allow children to be able to study schoolwork at night. China estimates that by changing to LED lighting it will save them as much electricity as the maximum planned output of the Three Gorges Dam. “They are going to dominate conventional illumination, it’s only a matter of time,” said Craford.

Packaging technology for ICs continues a steady evolution, with few examples more telling than the wirebonder. Wirebonders have periodically been considered as limited, but they evolve and now can go to 5 or even 8 levels of silicon useing new materials for dielectrics and interposers. FlipChip—which has been used almost exclusively for MCUs—is finally moving into the mainstream in combination with wirebonding and leadframes to allow for many efficient high-volume packages.. But SIP and SOC will continue to coexist in many possible variations using flipchip and wirebonding. PoP approaches also remain competitive, with variations using thinned silicon, recessed-cavities, and fan-in routing.

—E.K.