An embodiment comprises: a guide moving in the vertical direction or the horizontal direction; a transfer arm provided on the guide and loading spaced apart wafers; a laser emission unit disposed on the guide and emitting first laser beams at the spaced apart wafers loaded on the transfer arm; and a laser detection unit disposed below the transfer arm and collecting, from among the first laser beams, second laser beams having passed through gaps between the spaced apart wafers.

A substrate transfer device includes a manipulator, a substrate gripping hand, an actuator configured to rotate the substrate gripping hand about a roll axis, and a controller adapted to operate the manipulator to hold a substrate by a first engaging member and a second engaging member of the substrate gripping hand, then operate the actuator so that a first principal surface of the substrate is located above a base member, and a normal line of the first principal surface is oriented downward from a horizontal plane, and move a movable guiding member toward the tip-end part of the base member so that the second engaging member, a third engaging member, and the movable guiding member grip the substrate.

A substrate transfer device includes a manipulator, a substrate gripping hand, an actuator configured to rotate the substrate gripping hand about a roll axis, and a controller adapted to operate the manipulator to hold a substrate by a first engaging member and a second engaging member of the substrate gripping hand, then operate the actuator so that a first principal surface of the substrate is located above a base member, and a normal line of the first principal surface is oriented downward from a horizontal plane, and move a movable guiding member toward the tip-end part of the base member so that the second engaging member, a third engaging member, and the movable guiding member grip the substrate.

An embodiment comprises: a guide moving in the vertical direction or the horizontal direction; a transfer arm provided on the guide and loading spaced apart wafers; a laser emission unit disposed on the guide and emitting first laser beams at the spaced apart wafers loaded on the transfer arm; and a laser detection unit disposed below the transfer arm and collecting, from among the first laser beams, second laser beams having passed through gaps between the spaced apart wafers.

A substrate processing apparatus includes a substrate processing section that processes a plurality of substrates assuming a vertical posture in a batch manner; a first traversing mechanism that laterally moves a first traverse holding portion along a first traversing path between a substrate transfer position and a substrate delivery position; a second traversing mechanism that laterally moves a second traverse holding portion along a second traversing path disposed below the first traversing path between the substrate transfer position and the substrate delivery position; an elevation mechanism that raises and lowers an elevation holding portion in the substrate transfer position; and a main transfer mechanism that conveys a plurality of substrates assuming a vertical posture in a batch manner between the substrate delivery position and the substrate processing section, the first and second traverse holding portions, and the elevation holding portion each holds a plurality of substrates assuming a vertical posture in a batch manner.