BACKGROUND:  Several industries, such as the semiconductor and packaging industries, commonly uses plasma generators in equipment designed for fabricating circuits with demanding precision requirements. Helicon sources have many industrial uses because of their superior efficiency in generating dense plasmas. However, these sources require a DC magnetic field, which increases the cost and complexity compared with other RF plasma generators. A possible solution would be to replace the electromagnets with permanent magnets (PMs), which would reduce cost and complexity issues. For PMs to be a viable replacement, however, a device must be designed to counteract the PM's tendency to direct plasma into the walls rather than inject it into the process chamber because of PM field lines.

INNOVATION:  Researchers at UCLA have designed a Helicon source that creates plasma in the remote, reverse field of PMs, which permits injection of plasma into a useful volume. By adjusting the spacing between the PMs, the remote field can be controlled and Helicon discharge directed into the chamber in nearly straight lines. Using this method, the PMs can successfully replace electromagnets and allow the plasma generator to guide the Helicon discharge properly. For applications involving large substrate areas, such as web coating, an array of multiple Helicon sources can be used effectively.

POTENTIAL APPLICATIONS 

• Industrial semiconductor fabrication equipment for plasma etching and PECVD.
• Web coaters for plastic and fabric coating, such as flat panel displays.

ADVANTAGES

• Reduces the complexity of plasma generator designs by replacing the electromagnet component with a permanent magnet.
• May lessen costs normally incurred by costly electromagnetic components.

DEVELOPMENT-TO-DATE:  The innovation has been conceptualized, designed, and constructed. It has successfully demonstrated Helicon discharges using the remote field of permanent magnets.

Reference: UCLA Case No. 2005-683

PCT Patent Application: WO/2007/002455