Chemical Makers Show New Approaches to Semiconductor Supply, Manufacturing
Applied Materials, Inc. (AMI, Santa Clara, CA), and collaborator Ausimont (a subsidiary of Italy's Montedison Group) used Semicon Southwest to introduce a new, more environmentally friendly fluorine-based etch chemistry. AMI says its new Sifren 46 (C4F6) etch chemistry delivers higher etch rates, better profile control, and improved selectivity.
The system is designed for use in AMI's dielectric etch systems, which are used to produce next-generation copper-based semiconductor chips. According to market researcher Dataquest, the industry purchases of dielectric etching equipment will reach $2.2 billion by 2003, from $954 million in 1998. This makes it the fastest-growing segment of the etching market.
Etchant Advantages
"Sifren 46 gas improves dielectric etch process results in key areas such as copper dual damascene, self-aligned contact and high aspect ratio contact etch applications, including low K materials," says AMI Etch Group VP Gerald Yin.
"We are currently testing Sifren 46 with several customers to etch a variety of devices and have demonstrated significant advantages on small features. Chipmakers using our dielectric etch systems can benefit from these advanced process capabilities as they move their designs to 0.15 micron and beyond."
"It also exhibits significant environmental benefits over current etch chemistries," says Yin. AMI says C4F6 gas has low global warming emissions and zero ozone depletion potential.
AMI hopes to add luster to its growing reputation for green processing solutions. It recently received one of ten US EPA Climate Protection Awards for Remote Clean. The system substitutes neutral fluorine (from NF3) for perlfuorocompounds (PFC) used to remove buildup from the walls of chemical vapor deposition (CVD) chambers. PFCs are long-lived molecules that contribute to global warming. Remote Clean reduces emissions global warming gases by two orders of magnitude.
Ausimont describes AMI as the largest etch company in the world. "As we expand our presence in the semiconductor industry, we are happy to have Applied Materials as a technology partner," says Ausimont VP of Research & Development Massimo Malavasi. Ausimont is a major producer of fluorochemicals and fluoropolymers.
AMI has filed several patents covering Sifren 46 use and is making the etchant available to customers through major gas distributors.
Fluids Handling
Air Products and Chemicals, Inc. (Lehigh Valley, PA), for example, introduced its new Gasguard BSGS low-pressure, high-volume trichlorosilane (TCS) and silicon tetrachloride delivery system from containers of up to 40,000 lb.
TCS is a silicon source for epitaxial wafer coating, while silicon tetrachloride is used in fiber optic applications. Both products are typically delivered in 55-gal drums or stationary tanks. Gasguard Bulk Specialty Gas System (BSGS) is designed to use larger ISO modules, which hold up to 40,000 lb of liquids.
Although it can also tap traditional drums and tanks, the use of larger ISO containers reduces safety and quality risks associated with transfill to traditional tank installations. It also allows companies to buy chemicals at less expensive bulk prices.
"The electronics industry has struggled far too long with TCS and silicon tetrachloride issues from source container to the point of use," says Air Products' BSGS manager Robert W. Ford.
"We have eliminated product transfill at the customer site using a prequalified source of bulk product, conveyed through Air Products' bulk delivery system, liquid valve manifold boxes, and bubblers, to the tools.
"This integration alleviates the problems associated with handling these corrosive liquids while improving the consistency and reliability of the gas mixture supplied to the process. With our multitool bubbler design, the customer can save even more versus traditional approaches," Ford explains.
Ford also got to show off a new high-pressure, high-flow hydrogen chloride (HCl) purifier for installation in the flow train of its HCl BSGS. The unit delivers extremely dry, pure HCl, which is used as a cleaning and etching agent in a variety of semiconductor processes.
Dryness is critical in all these applications, since even parts-per-million moisture levels form yield-killing oxide contaminants and reduce etch selectivity.
Air Products' HCl purifier not only minimizes moisture in the HCl stream, but also ensures a consistent moisture level so there is less variation from trailer to trailer and tube to tube. It also reduces variation caused by vaporization of the liquid HCl inside a container. The unit is 28 in. long by 4.5 in dia, and has 0.5-in. VCR inlet and outlet connections that contain 20 mirofilters. It achieves maximum HCl flow of 1200 slpm with maximum operating pressures of 2000 psig at 50 C.
"As manufacturers seek new methods for improving product consistency and purity and for saving time and money, we believe BSGS systems will become more prevalent," says Ford.
For more information: Gerald Yin, VP, Etch Group, Applied Materials, Inc., 3050 Bowers Ave., Santa Clara, CA 95054. Phone: 408-727-5555. Fax: 408-748-9943.
And: Robert W. Ford, Bulk Specialty Gas System Manager, M/S C3005, Air Products and Chemicals, Inc., 7201 Hamilton Blvd., Allentown, PA 18195-1501. Phone: 610-481-7953. Fax: 610-481- 5900.
By Alan S. Brown