Automatic calibration system for wafer transfer robot

摘要

A system for automatically calibrating a semiconductor wafer handling robot so that the robot will move wafers into and out of precise locations within enclosures that form process stations or storage cassettes is disclosed. The system comprises a controller having memory and logic sections connected to a robot having an articulated arm that is movable in vertical (Z), horizontal (&thetas;), and radial (R) directions and having a wafer retaining wand at the end of the arm. Dimensional characteristics of the robot wand and the enclosures are stored in the controller memory. Sensors are provided at each enclosure and/or the robot wand which are activated and provide signals to the controller that are relative to the wand position. The robot is programmed to execute a series of progressive movements at each enclosure location which are controlled by a combination of sensor response signals and the appropriate dimensional characteristics. At the end of the programmed movements, the robot wand is positioned within a process station or cassette so that it can engage for removal or release a wafer therein at a precise predetermined location. <IMAGE>