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SAFC Hitech has launched the EpiVapor metalorganic vapor-phase distribution system, which eliminates localized tool bubblers and temperature control units (TCUs) by delivering vapors from highly volatile and sensitive pyrophoric liquids directly to MOCVD systems (enabling considerable cost savings).

An extension of the firm’s industry-proven EpiFill bulk liquid delivery technology, EpiVapor provides gas-phase delivery of chemical vapors such as trimethylgallium (TMG) and trimethylaluminum (TMA) directly to multiple deposition tools in a safe, reproducible way. Flexible enough to connect to up to eight independent tools, the continuous delivery of metalorganic vapors offers an uninterrupted fabrication of devices, the firm says. The system’s design ensures precursor flux stability in hydrogen (or other inert carrier gases) throughout the life of the ampoule, while adjustable parameters ensure that processes can be run at full capacity without stoppages to change out the tool bubblers. This optimizes process efficiency, reduces operational costs and increases safety, without compromising performance levels, the firm claims.

“As the MOCVD industry moves into high-volume manufacturing, overall cost of ownership (COO) has become an important consideration in cost control,” says president Barry Leese. “Reducing the cost of transporting metalorganic chemicals to the tool plays a significant part in reducing overall COO,” he adds. “The reliable, flexible and highly controllable dosimetry of organometallic precursors is of paramount importance in production environments where downtime is prohibitively expensive. The success we have seen with our EpiFill technology for pyrophoric materials motivated us to develop a vapor distribution system,” he continues. “With the introduction of the EpiVapor system we are reducing both system down time and the amount of hardware used per tool, eliminating the need of multiple temperature controller units and enabling automation and bulk chemical change-out in an arrangement that can be tailored for the specific requirements of the customer.”

The EpiVapor features a user-friendly LCD touch screen display that shows the process flow diagram and user interface. The touch screen displays information including bulk tank liquid levels, valve configurations, fluid and vapor flow paths and system pressure/vacuum - simplifying the operation of the unit in both automatic (auto) and manual (service) modes - as well as an alarm screen, recipe screens, programmable set points and multilevel password protection for added security.

The chemical section of the system consists of a cabinet that is enhanced for the use of pyrophoric materials with smoke detectors, audible and visual alarms, a watchdog system for automatic operation, optional UV/IR flame detector, 110% containment spill tray, and a manifold with fail safe pneumatic valves. The system is both S2-93/98 and S2-0200 certified and is CE marked.

Other components built into the system include a pressure transducer, pressure controller, a Venturi vacuum generator, a vaporizer bubbler fitted with continuous and fixed-level sensors, and a TCR2000R temperature control unit (TCU).

Applications include:

• precursor vapor delivery for production MOCVD/ALD deposition systems;
• TMG delivery for MOVPE of heterojunction bipolar transistors (HBTs) and high-brightness LEDs (HBLEDs);
• delivery of TMG and DEZ (diethyl zinc) for MOCVD of solar cells;
• TMA delivery for ALD of Al2O3 high-k dielectric for logic, memory, and MEMS devices; and
• other high-volatility III-V and silicon precursors.

*SAFC Hitech has also launched the OM700, a bubbler that offers a cost-efficient migration path to controlled delivery of organometallic precursors for larger lot sizes (enabling a reduction in process downtime, combined with increased safety controls).

The firm claims that the OM700 offers reliable and very controllable dosimetry of highly sensitive organometallic precursors, such as trimethylgallium (TMG), trimethylaluminum (TMA) and triethylgallium (TEG), in production environments where downtime is prohibitively expensive. The large capacity, which can support up to 13kg of precursor, reduces the frequency of container change-outs, minimizing downtime and bubbler manipulation safety hazards by enabling larger batch sizes. Also, the bubbler’s flux stability covers a range of operating temperatures from –10ºC to +30ºC, ensuring that all processes can be run at peak efficiency.

The combination of these advantages in a production environment results in reduced operational costs without compromised performance, the firm claims. In existing large bubbler technology, maintaining temperature control is often difficult because they use conventional heater baths. Also, the size of the bubbler is restricted to that of the installed bath. Instead, the OM700 has an independent heating jacket and thermal control system that enable an increased volume to accommodate over 9 liters of metal alkyl, while still maintaining strict temperature and operational controls.

“As the demand for higher throughput and process efficiency grows, more efficient methods for precursor delivery will be required,” says R&D director Dr Peter Heys. “We are seeing significant demand in this area, and the OM700 complements our range of solutions,” he adds. “Our EpiFill system has been proven for many years, and our new EpiVapor unit builds on this technology for true, large-scale operation, with the OM700 now offering an attractive intermediate solution.”

See related items:

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SAFC’s Hitech segment focusing on semiconductor sector

Epichem acquired by Sigma-Aldrich for $60m

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