Microstripline Circuits for Microwave Plasma Discharges
Introduction Widely used in a variety of products and processes, plasmas are generated by applying a voltage between electrodes to facilitate gas ionization. The voltage may be static (DC) or varying at a fixed rate that can be in the RF range (<100 KHz) or as high as tens of MHz in frequency. Typical plasmas have a characteristic physical dimension on the order of 40 to 80 cm. Smaller plasmas can be generated via waveguide or cavity structures and exciting frequencies in the microwave regime (>1 GHz). However, the necessary electrode structures become increasingly small and more difficult to fabricate as the target size of the discharge is reduced. Description of Technology MSU’s invention is a method for using stripline microwave applicators for the creation of plasma discharges with a characteristic physical dimension between a millimeter and tens of microns. The microstripline conductors that couple the microwave energy (at 300 MHz to 30 GHz) are transverse to the microwave discharge. Key BenefitsSmall size: The plasma can be as small as 10 to 20 microns.Volume expansion: A surface wave created in the plasma can extend the plasma far outside the excitation region in one dimension.Low power: RF power as low as 1 to 2 watts is sufficient to excite the plasma.Ease of manufacturing: Well known, mature, and easily fabricated microstripline technology is used for the actuator structure. These structures can be easily integrated with MEMS technology to create system-on-a-chip (SOC) structures.High density: The high density plasmas Applications Miniature plasmas can be used in a wide variety of applications:Chemical/biological lab-on-a-chip devicesSmall spectrometers, lights, ion pumps, and gas flow controllersLocalized semiconductor processingCleaning, sterilization, or coating of MEMS structuresManufacturing of highly uniform nanoparticles from gas precursorsFunctionalized polymers, tunable plasma antennas, and paint removal Patent Status US 6,759,808 Inventors Timothy Grotjohn, Jes Asmussen, Andy Mijaya Tech ID TEC2002-0015
USA
