| 摘要 |
Electrostatic clamping techniques for use in clamping substrates in various semiconductor fabrication processes are disclosed. One embodiment takes the form of a substrate support plate (5) which has deposited on its working face two layers (12A, 12B) of thermally conductive, electrically insulative RTV silicone, between which layers is located an interdigital type printed circuit capacitor (7) energized by a DC source (V) in the kilovolt range. Secured to the back surface of the support plate (5) is a water-cooled jacket (6) with the entire assembly adapted for location in the incident ion beam (2) and having good thermal dissipation properties. An alternate implementation utilizes an alumina support plate on which the capacitor of aluminum composition is deposited by vacuum evaporation, and the exposed capacitor surface is rendered insulative by oxidation. A second embodiment employs a substrate hold down plate (15) which has on its working face an interdigital type printed circuit capacitor (18A, 19A) covered by an outer layer (21) of electrically insulative, compressible, resilient, RTV silicone. The capacitor (18A, 19A) is an electrostatic field generator energized by a DC source in the kilovolt range. In a typical application, there is secured to the back surface of the hold down plate (15) a water-cooled jacket with the entire assembly adapted for location in the incident ion beam and having good thermal dissipation properties. The substrates to be clamped are supported in a plate-like carrier (30) having flanged apertures (31) for laterally confining the substrates. The carrier is secured to the hold down plate (15), thereby bringing the substrates into proximity with the electrostatic field generating capacitor (18A, 19A), and also masking those areas of the hold down plate not covered by the substrates. When the capacitor (18A, 19A) is energized, the substrates are attracted towards it. The outer silicone layer (21), being compressible, provides improved proximity of the clamped substrate to the hold down plate (15). For facilitating release, the carrier incorporates a manifold (35) designed to supply gas under pressure to the substrates to free them from the hold down. |
