Applied jumps into cleaning systems for CMP tools
[Special attention to the OnTrak commentary .... and my addition to the last paragraph ... which is in bold ... --Duker]
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Story updated 2:30 p.m. EST/11:30 a.m. PST, 6/10/99
SANTA CLARA, Calif. -- Applied Materials Inc. here today announced its move into the wafer cleaning arena with the launch of an integrated system for chemical mechanical planarization (CMP) tools that combines brush scrubbing modules with a single-wafer megasonic bath.
Until now, Applied has offered integrated CMP cleaning systems using equipment from the OnTrak Systems subsidiary of Lam Research Corp. and DNS Korea Co. Ltd. The move into cleaning systems is aimed at boosting Applied's momentum in the CMP tool market, where the company captured a 40% of the sales last year, according to industry projections (see story in June publication of SBN).
Applied's new Mirra Mesa system integrates a four-step cleaning process with the company's Mirra CMP system, providing dry-in/dry-out processing. Applied configured the integrated cleaner on its Mirra in a way to easy access to important components in both the CMP tool and cleaning system for service and maintenance, said Rob Davenport, director of product management for Applied's CMP Division.
"We paid a lot of attention to the layout of the system and configured it not only to optimize the floor space in a fab but also to provide easy access to every part of the polisher and cleaner as well as robotics and interfaces," Davenport said. "We had a lot of debates internally about the shape and whether a square system looked nicer but in the end we decided functionality was more important than conforming to an industry norm." Three sides of the Mirra CMP polisher are available for replacing the tool's three polishing pads, for example.
Another key development in the Mirra Mesa is the marriage of a single-wafer megasonic module with two brush-scrubbing modules. Applied developed a megasonic module to complete its cleaning step in about 30 seconds for high wafer throughput, Davenport said.
"Typical batch megasonic systems have processes that take on the order of five minutes," he said. "If you have to integrate a five-minute process in a cleaner, you've got a problem. One of our challenges was to create an efficient process and get the time down to around 30 seconds." The single-wafer megasonic bath does not cycle power on and off like other [multi-wafer] batch systems. And it has been designed to eliminate the problem of "shadowing."
The combination of brush-scrub and megasonic cleaning enables the system to clean slurries and residues off wafer surfaces and out of tiny trenches or other features on substrates. Applied's brush-scrubbing modules uses 3-inch diameter brushes which rotate at high speed--up to 700 rotations per minute. The megasonic bath module is used to remove slurries from small features and it is more efficient in removing oxide slurries from the bevel region of wafers, Davenport said.
"We believe this to be the only single-wafer megasonics bath to be integrated into cleaning system," he said. "We thought about going to advanced technologies or non-contact cleaning and advanced drying techniques, but in the end we decided that might be too big of a leap and we'd be stretching our customers' knowledge. Therefore we stuck with double-sided brush scrub technology, and spin/rinse/dry technologies, using standard chemistries, but we added the single-wafer megasonics bath."
The Mirra Mesa is suitable for oxide, tungsten and copper materials. The system has been verified production-ready with extensive testing, Davenport said, and Applied has received several orders from customers in the United States and Asia, according to the company.
The cleaner can be configured with up to four separate process modules: a single-wafer immersion megasonic module, two double-sided brush scrubber stations and a spin rinse dryer.
Wafers are gripped at the edge and submerged vertically into the modules where they are cleaned on front and back sides. The vertical orientation and serial arrangement of the Mesa's cleaning modules help minimize footprint, improves process performance and transfers five wafers simultaneously. Each module requires just 30 seconds of process time, Applied said.
The liquid delivery modules support a variety of industry standard chemistries including HF in the brush modules and heated RCA chemistries in the megasonic module. For copper interconnects, the Mesa cleaner supports Applied's proprietary ElectraClean solution.
While Applied is now offering its own cleaning systems, it will continue to sell CMP tools with OnTrak and DNS cleaning equipment. BEACAUSE INTC LIKES THEIR MIRRAs COUPLED WITH ONTRAK CLEANERS!!!
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