Applied enters brightfield wafer inspection market
Mark LaPedus
EE Times
(06/06/2005 3:00 PM EDT)
SAN JOSE, Calif. — Taking on Hitachi, KLA-Tencor and others, Applied Materials Inc. on Monday (June 6) entered the brightfield wafer inspection business, rolling out what it claims to provide the world's first laser-based, three-dimensional capabilities in the arena.
Based on a 266-nm deep ultraviolet (DUV) laser source, Applied's UVision is an advanced brightfield wafer inspection system, said to detect a new class of "killer" defects down to 30-nm sensitivities for the 65-nm node and beyond.
Enabling simultaneous brightfield and 3D imaging in advanced 300-mm applications, the die-to-die tool can process 2-gigabytes of data — or the entire Star Wars movie collection — in just two seconds, according to Applied (Santa Clara, Calif.).
"The introduction of new materials and processes at the 65-nm technology node has produced new classes of small defects that directly affect fab yield," said Gilad Almogy, vice president and general manager of Applied's Process Diagnostics and Control Group. "The UVision system has proven its value for critical chip layers, such as shallow trench isolation, contact, poly and gate etch, where chip makers have isolated killer defects not found with traditional brightfield tools."
The UVision has several advantages over competitive machines, based on traditional lamp-based illumination technologies, added Yogev Barak, chief marketing officer for the Process Diagnostics and Control Group at Applied. "You can find defects with a lamp," he said in an interview with EE Times "But you don't have enough intensity with the lamp."
Applied's entry into the brightfield inspection market was somewhat expected, as word began to leak out about the company's product in the media last week. As reported, Applied is expected to compete in the brightfield inspection business against market leader KLA-Tencor Corp. (San Jose) (see June 3 story).
Japan's Hitachi High-Technologies Ltd. is also quietly offering a brightfield inspection tool. The new HA-3000 brightfield inspection tool from Hitachi (Tokyo) is based on DUV optics and advanced image processing for sub-70-nm sensitivities.
A few startups are also attempting to crack the market, but all vendors will face an uphill battle in displacing KLA-Tencor, said Dean Freeman, an analyst at Gartner/Dataquest. "Blasting KLA out of the water will be difficult," he said.
On the other hand, there's room for new vendors like Applied, he said. In total, the optical wafer inspection market is approximately a $900 million industry, according to Applied. Brightfield inspection is the biggest segment in wafer inspection, representing about a $500 million market, according to the company.
Bright vs. dark vs. e-beam
In wafer inspection, there are three main technologies: darkfield, brightfield and electron-beam. Darkfield inspection provides higher throughput at a lower cost for wafers, but the technology is "less sensitive." It is used to "detect defects with some topographic features such as scratches and particles," according to Applied.
At the high-end, e-beam technology is used to find tiny defects. E-beam inspection is the "most sensitive" of all technologies, but it is also expensive and slow.
Brightfield fits in the in middle between darkfield and e-beam, as it is characterized as a high-sensitivity technology, with moderate-to-low throughput. "Brightfield technology is primarily used to detect flat pattern defects as well as smaller three-dimensional defects such as voids and residue," according to Applied.
Until now, Applied competed in the darkfield and e-beam wafer inspection markets. Now, the chip-equipment giant offers tools in all three markets, as it has begun selling a brightfield machine.
Applied claims it has taken brightfield a step further. Traditional brightfield systems are similar to microscopes; they use a multi-wavelength lamp source, a single-light detection channel and CCD detection to "provide users with limited imaging capability," according to Applied.
In contrast, Applied's UVision system illuminates the wafer via a 266-nm laser source. The light is converted to multiple beams via a scan module within the machine.
Then, the light from the wafer is reflected back into two separate channels or detectors. One channel is geared for brightfield imaging, while the other is aimed for 3D inspection.
Each channel consists of a collection of photomultiplier tubes (PMTs), which "allows high sensitivity even in low light situations without compromising throughput," according to Applied. "Simultaneous brightfield and 3D imaging rapidly detects both shallow-pattern defects (brightfield channel) and topographical defects such as particles and voids (3D channel) in a single scan."
The tool makes use of an imaging processor, which handles data at 2-Gbytes in only two seconds. It also features an optical resolution of 1013 pixels on 300-mm substrates. Total throughput is two wafers per hour for the machine.
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