Media Coverage and Awards
ReVera starts life with a tool for gate metrology
Mark LaPedus -- EE Times, 2/ 23/2004
Sunnyvale, Calif. - Startup ReVera Inc. has formed a semiconductor-equipment company to compete in the emerging compositional-metrology arena.
After opening for business last month, ReVera received first-round funding and officially launched its first tool, for gate film-thickness and compositional-metrology applications at 130 nanometers and beyond. Crosslink Capital and members of ReVera's executive management team have invested in the company. The amount of the funding, earmarked for expansion of product development and support infrastructure, was not disclosed.
At the same time, the company has officially rolled out its first product-the RVX 1000, billed as a high-precision gate metrology tool. Using X-ray photoelectron spectroscopy, the RVX 1000 can simultaneously run multiple, automated measurements, including film thickness and elemental concentration in gate dielectric applications, said Thomas Larson, vice president of marketing. "Our first application is the gate dielectric," he said. "This includes the nitrided gate oxides being used almost universally at 130 nm and below. It also includes the high-k gate dielectrics now under development."
ReVera traces its roots to metrology and analytical-instrument maker Physical Electronics Inc. (Eden Prairie, Minn.). Last year, Physical Electronics agreed to transfer its analytical-instrument product lines to Ulvac-Phi, its joint venture with Japan's Ulvac Corp. Physical Electronics is part of High Voltage Engineering Corp. (HVE), based in Wakefield, Mass.
Physical Electronics also had an internal division, which continues to develop a gate metrology tool for semiconductor apps. After two or so years under its parent company, the metrology unit implemented a leveraged buyout and formed ReVera last month. "We've parted from HVE," Larson said. "We've raised money and now we're an independent company."
Dave Ring, president and CEO of Physical Electronics, now holds similar titles at ReVera. Ring also held executive positions at ATE provider LTX Corp.
ReVera itself is entering what the company calls the new "compositional-metrology market." According to estimates, the overall market for film metrology tools can expect a compound annual growth rate of 25 percent to $1.1 billion by 2007.
In film metrology, the company potentially competes against the likes of KLA-Tencor, Nanometrics, Rudolph and ThermaWave, among others. But unlike competing metrology tools, ReVera's RVX 1000 performs compositional metrology, especially for current and future gate stacks.
Turnkey solution
For these applications, chip makers tend to have their own captive labs, which perform these functions via analytical instruments. But turnaround time can be slow.
ReVera's RVX 1000 is designed to solve these issues for 130-nm applications and below in 200- and 300-mm fabs. The tool is a turnkey, small-footprint system, based on X-ray photoelectron spectroscopy.
It is geared for advanced gate metrology. Today's leading chip makers are moving toward a modified form of silicon dioxide for gate stacks, adding nitrogen to the mix to create silicon oxynitride as the gate dielectric material.
This approach leads to reductions in the equivalent oxide thickness while maintaining acceptable leakage current for low-voltage operation. The technique employed by the ReVera RVX 1000 utilizes a highly stable, high-flux X-ray source in conjunction with enhanced photoelectron detection optics and advanced algorithms to determine nitrogen concentration and layer thickness with high precision.
To perform these tasks, the company said, the tool deploys a monochromatic X-ray beam, which induces the emission of electrons from the surface of the sample. The electrons that are detected lack the energy to escape from a depth of more than ~10 nm, making the technique inherently surface-sensitive. The binding energy of the emitted electrons is measured over a broad spectral range and used to identify and quantify the elements present.
Unlike traditional optical methods, which use some form of contamination-sensitive ellipsometry to determine thickness, the RVX 1000 counts only the atoms of interest (Si, O, N, Hf and Al, for example). That makes it immediately applicable to current-generation gate dielectrics and readily extendable to next-generation systems, such as high k dielectrics and strained silicon, the company said.