Characterization of a slot antenna microwave plasma source for hydrogen plasma cleaning

Abstract

A new large volume microwave plasma source has been used for the production of a hydrogen plasma. The source consists of an annular waveguide cavity with axial slots on the inner side which acts as a field applicator to sustain a plasma at 2.45 GHz. The plasma is contained in a fused silica bell jar of 16 cm in diameter and 20 cm in height. The distance between the slots corresponds to a waveguide wavelength. The source is able to generate a highly dissociated (up to 90%) hydrogen plasma for cleaning purposes. Stable operation of the plasma source is shown for a pressure range of 0.1–1.3 mbar and a power range of 600–2000 W. The plasma can be ignited over the entire examined pressure range, and the power needed for discharge ignition is below 1.7 kW. The minimum ignition power is 1050 W for a pressure of 0.7 mbar. A double Langmuir probe and optical emission spectroscopy were used to characterize the hydrogen plasma as a function of microwave power, pressure, and position. The results indicated a typical ion density of 1.5×1011 cm−3 which is an order of magnitude less than that obtained for argon under similar conditions. The typical electron temperature is 2.5 eV for microwave power of 2 kW and pressure of 0.7 mbar.

A modified broad beam ion source for low-energy hydrogen implantation

“…Since the dissociation energy ͑8.5 eV͒ 7 of H 2 ͓reaction ͑1͔͒ is much less that the ionization energy ͑15.4 eV͒ 21 of hydrogen molecules ͓reaction ͑3͔͒ and even less than the energy for reaction 2 ͑18.0 eV͒, 21 we assume that the reaction to dissociate H 2 is favored. 7 Thus, we believe that at low vacuum chamber pressure (3 ϫ10 Ϫ4 mbar) the content of H 2 ϩ in the plasma is higher than the content of H ϩ . 7 Further, the energy ͑13.6 eV͒ 21 for hydrogen atom ionization ͓reaction ͑4͔͒ is lower than for hydrogen molecules, and the collisional cross section for ionization of molecules is only slightly higher than that for atoms.…”

“…The standard method to incorporate hydrogen into a sample 1-5 or to clean semiconductor surface [6][7][8] with hydrogen is the utilization of different hydrogen plasma sources, but there is almost no information 9,10 about using broad beam ion sources for low-energy hydrogen implantation (Ͻ1 keV). The standard method to incorporate hydrogen into a sample 1-5 or to clean semiconductor surface [6][7][8] with hydrogen is the utilization of different hydrogen plasma sources, but there is almost no information 9,10 about using broad beam ion sources for low-energy hydrogen implantation (Ͻ1 keV).…”

55‐3: Development of Low‐Temperature Metal Dry‐Etching Equipment via ECR Plasma Source

“…Based on the ECR plasma, the ratios show ideal Maxwellian electron energy distribution. In Ag dry etching, when the cylindrical ECR plasma source has 2.5 eV electron temperature [12,13], the H + /Cl + ratio is around 1 for the minimum…”

Planar Plasma of 30 cm Diameter Maintained by Hybrid Surface Microwave through Annular Slot Antenna

“…Various types of microwave antenna have been designed for exciting large-area and large-volume SWP successfully. [1][2][3][4][5][6][7][8] Among the various types, slot microwave antennas in various types have been popularly adopted to excite SWP. Microwave power is coupled into the chamber through the slot antenna, thus high-density plasma could be produced near the slots subsequently, the surface wave is excited and transmitted along with the interface between plasma and the surface of dielectric plate to create large-area plasma.…”