Why Monitoring Signal Integrity In Wafer Handling Robots Is Essential?
The reliability of the control signals which are used to regulate wafer handling robots is examined by a monitor that is attached to numerous points of the robotic control system. The monitor connected to the control system consists of a memory that stores and hoards data sets signifying correct, reference features of the control signals. The monitor divides the control signals into sections at several points in the control system and matches these tested signals with the already stored reference characteristics so as to identify whether there is any signal inconsistency. In case if inequality exists, the monitor will generate an error. Here, we will broadly explain an automated transport system that is used in semiconductor manufacturing processes, and deals more chiefly with a method for observing signal integrity in a wafer handling systems.
An insight into the invention Robotic systems are widely used in semiconductor manufacturing processes with an objective to reduce participation of the operator, enhance efficiency and reduce probable contamination during the operations. These robots are normally deployed to transfer semiconductor wafers between storage places and a variety of processing locations. For instance, a single robot is used in a cluster tool which comprises of a flexible, multichamber, integrated processing structure. The robot is contained in the central wafer handling unit and operates to transfer the wafers between various peripheral process slots. The robot is supervised by a controller like PLC which is attached by a multi-conductor electrical wire and parallel connectors to a robotic device. The controller and the robotic device have a plurality of electrically intersected mechanisms through which control signals run for identifying the robot functioning. For instance, the controller will specifically contain a motor controller and a motor drive. The robot will consist of various motors and corresponding shaft encoders which generate feedback signals that in turn reveals of the position of robot. These electrical connecting cables and related connectors signify chances for errors to be introduced into the signals as a consequence of a number of sources which might include electrical intrusion, open circuits, shorts, and signal intersection. So if any of these errors got introduced in the control signals due to any of the above mentioned reasons, it can consequently effect robot operations and may result in malfunctioning of the robots. It can even lead to breakage of wafer or damage of the equipment. It is difficult to maintain integrity of the signals as the robots age with time and all the connectors and wiring associated with it start deteriorating. Previously, control signal integrity issues have been identified only when an error gets introduced into the control signal which in turn produces a corresponding error in the robot movement. Also, even after discovering issues with control signal integrity, it is very complex to identify the exact underlying location of the issue that took place. So there’s a requirement of a real-time control signal monitoring in wafer handling robots system that efficiently and quickly identifies whether an error has been introduced into the control signal or not. The monitoring system should also determine the location at which the error has been introduced.