Light curtain safety system for semiconductor device handler

A light curtain safety system for controlling a semiconductor device handler, the semiconductor device handler including a control unit and a robot mechanism that is selectively operated in response to signals generated by the control unit, wherein the light curtain safety system comprises:

• a light curtain apparatus for generating a light curtain adjacent to the robot mechanism such that accessing the robot mechanism requires breaking the light curtain;
• and
• a safety control circuit including:
• a light curtain control module for transmitting an emergency power off signal to the semiconductor device handler when the light curtain apparatus is activated and the light curtain is broken;
• and
• an operating state detection circuit for detecting an operating state of the semiconductor device handler, and for generating a mute control signal for controlling the light curtain control module such that the light curtain can be de-activated only when the operating state of the semiconductor device handler is in a predetermined operating state.

A method for retrofitting a semiconductor device handler to include a light curtain safety system, the semiconductor device handler including a control unit and a robot mechanism that is selectively operated in response to signals generated by the control unit, wherein the method comprises:

• positioning a light curtain apparatus adjacent to the semiconductor device handler such that accessing the robot mechanism requires breaking a light curtain generated by the light curtain apparatus;
• detecting an operating state of the semiconductor device handler by sensing an associated signal generated in the control unit;
• controlling the light curtain apparatus such that the light curtain apparatus is activated only when the semiconductor device handler is in a first predetermined operating state, wherein when-the light curtain apparatus is activated, an emergency power off signal is transmitted to the control unit when the light curtain is broken;
• and
• controlling the light curtain apparatus such that the light curtain apparatus is de-activated only when the semiconductor device handler is in a second predetermined operating state.