Automated Wafer Warehouse Management due to RFID System

Turck's BL ident RFID system coordinates the robot-supported stock placement and stock removal of intermediates in semiconductor production in China

One of the world's leading semiconductor manufacturers in China faced the challenge of storing the delicate silicon wafers safely between quality testing and packaging. These sensitive components must be stored in material racks until the next process step. In this process phase, the wafers were previously removed manually and the stock removal was documented on paper sheets. Not only was this time-consuming, but also prone to errors and provided only a poor overview of the material flow in the overall process. There was therefore a need for an automated solution that would guarantee a reliable and efficient process. 

Consequently, the customer now uses RFID in warehouse management to achieve fault-free and transparent production throughout the entire process. RFID storage location identification uses RFID tags to monitor which wafer is stored at which storage location during stock placement and stock removal or transfer. All stored wafers can therefore be found immediately if necessary.

  • A robot ensures reliable stock placement and removal of wafers in the shelf

  • The RFID tag is located on top of the wafer carrier

  • The BL20 RFID and I/O system from Turck ensures reliable communication with the PLC

  • RFID HF read/write heads read out the tags of the wafer carriers during stock placement and stock removal

Robot-based RFID solution 

Specialized high-performance handling robots play an important role in the automated processing of unprocessed wafers into integrated circuits. These Automated Guided Vehicles (AGVs) with integrated robotic arm navigate autonomously and guarantee reliable handling of the components between processes. In cooperation with a Chinese robotics company, Turck developed a complete RFID solution to use an AGV for material transport. The solution significantly reduces the supply time for the wafers and minimizes the work involved in this process step. The warehouse management system links the information from the RFID system with the information from the production control system (MES) and monitors all wafers in real time.

BL ident RFID solution convinces 

Turck's BL20 gateway fits well into the clean and tidy production environment. It forwards the data collected by the RFID and I/O modules in the field to the higher-level controller. The RFID tags are attached to the upper end of the wafer carrier. RFID read/write heads installed on the top of the wafer shelves automatically recognize the carriers and thus guarantee their reliable identification during stock placement and stock removal by the AGV.

LED displays provide clear information about the operating status of the read/write head and RFID module at all times. The large read distance of the read-write head allows the robot arm enough space to pick up and position the carrier. The epoxy resin carrier housing in protection class IP68 does not interfere with the reading process, nor does contamination on the surface. In addition, the tag can be reused, which is ideal in closed loop applications. And project manager Tao Zhang Yitao was impressed by even more advantages: "The preassembled cables can be installed quickly and guarantee secure data transmission. Above all, Turck's RFID products can be replaced quickly during operation, which significantly reduces downtime and makes maintenance of the devices quick and easy."

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