A Novel Helicon Plasma Source for Large-Area Displays

Helicon wave sources are known for the dense, remote plasmas they create for etching. Recently they have been found to also deposit high-quality oxide layers. By using an array of multiple sources, we hope to create a uniform plasma of arbitrary size for processing flat-panel displays. The dc magnetic field B that helicons require can hopefully be supplied by permanent magnets, thus avoiding the cost and complexity of large electromagnetic coils. The size, shape, and placement of each source will be optimized, as well as the antenna and rf frequency. 1. Source design: Previously [1] we have shown that an array of seven stubby tubes can cover a 400-mm substrate uniformly with density up to 10 cm. The shorttube effect has been explained by constructive interference from the wave reflected at the back. To optimize this effect at low B-fields we use the HELIC code developed by D. Arnush [2]. Guided by computations, we construct tubes of the type shown in Fig. 1. Sample computational results [3] are shown in Figs. 2 and 3. In Fig. 2, the distance d between the antenna and the back plate is varied, and a density peak is observed at varying B-fields. In Fig. 3, the antenna type is varied, and it is seen that