a base, defined with a central axis;

a plurality of fixed rings, stacked on the base along the central axis, each fixed ring comprising a through hole and a channel, each through hole passing through each fixed ring along the central axis, a ring groove disposed in each fixed ring along an inner rim of the through hole, and the channel extended from an outer periphery of each fixed ring and communicating to the ring groove;

a rotating shaft, rotatably coupled to each through hole, and comprising a plurality of flow passages, each flow passage comprising an interface and a port, and the port arranged corresponding to each fixed ring and communicating with the ring groove;

a turntable, fixedly connected to the rotating shaft, and comprising a plurality of carriers disposed on a side thereof away from the base, each carrier equiangularly installed around the rotating shaft, a top surface of each carrier carrying each wafer, each carrier comprising a suction passage, two ends of each suction passage coupled to the top surface of the carrier and the interface correspondingly, a plurality of channels correspondingly communicating with a plurality of ring grooves, the flow passages and the suction passages to define a plurality of air suction passages;

an air suction pump, coupled to each channel, and configured to extract air from each air suction passage to form a negative pressure to suck each wafer; and

a driving mechanism, configured to drive the turntable and the rotating shaft to rotate around the central axis;

wherein, when the turntable and the rotating shaft rotate, the port rotates relative to each fixed ring and keeps communicating with each ring groove.