Patent ID: 6805487
Filing Date: 2004-10-19
Classification: B23Q,F16C,H01J,Y10S

Abstract:
A holder driving device comprising:a holder holding a substrate, the holder provided in a vacuum vessel disposed in the atmosphere; a shaft supporting the holder and penetrating the vacuum vessel; a driver provided outside the vacuum vessel and driving the shaft reciprocatingly and linearly in an axial direction of the shaft; a bearing unit attached on the outside of the vacuum vessel so that the shaft passes through the bearing unit, and the bearing unit having at least one of mechanical linear motion bearings for supporting the shaft and at least one of exhaust chambers surrounding the shaft; a vacuum pump for vacuum-pumping the exhaust chambers of the bearing unit; and a gas replacement mechanism for supplying dry gas in the neighborhood of an atmosphere-side entrance portion of a gap between an end portion of the bearing unit of a side opposite to the vacuum vessel and the shaft passing the end portion, so as to replace the atmosphere in the vicinity of the entrance portion by the dry gas, the dry gas being lower in humidity than at least the surrounding atmosphere and being a positive pressure.