| 摘要 |
A force compensator is provided for a semiconductor processing apparatus having a moving member, in order to compensate for a fixed force on the moving member, such as gravity or atmospheric pressure. A vacuum and piston combination is connected between the movable member and a reaction point. One side of the piston is open to atmosphere and the other side defines an enclosed region which is evacuated. The cylinder is evacuated to a pressure which does not exceed 10% of ambient pressure during operation of the device, so that pressure changes in the low pressure region have minimal effect on the compensation force during movement of the movable member over its displacement range.
|
