A precision soft-touch gripping mechanism has a mounting plate attached to a
robot arm. The plate supports a
stepper motor. The output shaft of the
stepper motor is connected through a spring to an elongated finger that slides in a central longitudinal slot of the plate and supports a first
wafer gripping post, while on the end opposite to the first
wafer gripping post the mounting plate pivotally supports two L-shaped fingers with a second and third
wafer gripping posts on their respective ends. The mounting plate in combination with the first sliding finger and two pivotal fingers forms the end
effector of the
robot arm which is thin enough for
insertion into a wafer-holding slot of a wafer cassette. The end
effector is equipped with a mapping sensor for detecting the presence or absence of the preceding wafer, wafer position sensors for determining positions of the wafer with respect to the end
effector, and force sensors for controlling the wafer gripping force. Several embodiments relate to different arrangements of gripping rollers and mechanisms for control of the gripping force and speed of gripping required for gripping the wafer with a soft and reliable touch.