In some embodiments, when the load lock chamber 120 is ready for receiving the wafer from the factory interface 110, the valve V1 is open and allows the robot of the factory interface 110 to pass through and place the wafer in position. The valve V2 is closed, and the environment of the load lock chamber 120 has the same environment as the factory interface 110, i.e. the first environment. After the valve V1 is closed, the load lock chamber 120 is vacuumed to, for example, a low pressure such as about 200 m-torrs. Other pressures may also be used, for example, less than 10 m-torrs, as determined by the type of vacuum pump used for vacuuming the load lock chamber 120.

In some embodiments, when the load lock chamber 120 is ready for receiving the wafer from the buffer chamber 130, the valve V2 is open and allows the buffer chamber 130 to pass through and place the wafer in position. The valve V1 is closed, and the environment of the load lock chamber 120 has the same environment as the buffer chamber 130, i.e. a second environment (will be discussed below).

In some embodiments, the buffer chamber 130 includes a robot 131 which has at least one robot blade 132. The robot 131 is movable in three-axes and rotatable at any angles. For illustration in FIG. 1, the robot 131 is disposed at the center of the buffer chamber 130. The robot 131 has two robot blades 132, and the robot blades 132 are each attached to the opposite side of the robot 131. In some embodiments, the robot blade 132 is adapted for handling and transferring the wafer to and from various positions, for example, the load lock chamber 120.