| 摘要 |
An apparatus (114) and method which uses a plasma having a density gradient in order to accelerate ions, thereby producing a flow of energetic ions and neutral particles. The plasma gradient is produced by applying a non-uniform magnetic field to the plasma and/or providing non-uniform RF power to the plasma. Since the voltage within a plasma (i.e., the plasma potential) is dependent upon the density of the plasma, the plasma gradient produces an electric field within the plasma, which can be used to accelerate ions e.g., toward a substrate. This technique produces accelerated particles of lower energy than conventional systems, thereby causing less damage to a work piece (106) being processed. In addition, since the ions accelerated by the apparatus have lower speeds than those accelerated by conventional systems, a larger proportion of the ions having time to recombine with free electrons before striking the work piece (106) being processed. Since neutral particles are less damaging than ions, the amount of damage caused by the beam of accelerated particles is reduced further. As a result, manufacturing yields are increased, manufacturing costs are decreased, and improved lithographic resolution is possible, thereby improving the performance and reducing the costs of circuits fabricated on a substrate. |
