This article outlines the common cassette types used in wafer sorters and the wafer sizes they are designed to handle.

1. Common Cassette Types

FOUP (Front Opening Unified Pod)

The FOUP is the industry standard for 300mm wafer processing. Designed as a sealed carrier, it protects wafers from particle contamination and allows fully automated handling through SEMI-standard load ports.

● Key Features: Front-opening door, cleanroom sealing, automation-ready design

● Typical Use: Advanced 300mm fabs with full AMHS (Automated Material Handling Systems) integration

FOSB (Front Opening Shipping Box)

The FOSB is primarily used for wafer transport between fabs or from suppliers. It shares a similar front-opening design with FOUPs but is optimized for secure, long-distance shipment rather than intra-fab automation.

● Key Features: Shock-resistant construction, transport sealing

● Typical Use: Shipping wafers from foundries or suppliers to packaging houses

Open Cassette

The open cassette is a legacy but still widely used wafer carrier. Unlike FOUPs or FOSBs, it is not sealed, which makes wafers more vulnerable to contamination. However, open cassettes remain standard in 150mm (6") and 200mm (8") fabs, as well as in research and pilot lines.

● Key Features: Exposed slots, lightweight design

● Typical Use: Legacy fabs, R&D environments, or back-end processing lines

2. Wafer Sizes Handled by Sorters

Wafer sorters must accommodate different diameters of wafers, depending on the fab’s generation of equipment and product requirements:

150mm (6") Wafers:

Common in specialty semiconductor fabs, MEMS, and power device manufacturing. Typically paired with open cassettes.

200mm (8") Wafers:

Still widely used for automotive, analog, and power ICs. Often handled in open cassettes or customized SMIF pods.

300mm (12") Wafers:

The current mainstream in advanced logic and memory manufacturing. Exclusively handled in FOUPs or FOSBs to meet strict contamination control standards.

Many modern wafer sorters are multi-size compatible, capable of switching between 150mm, 200mm, and 300mm wafers with the proper carrier and robot configuration.

3. Matching Cassette Type and Wafer Size

The table below summarizes the typical compatibility between cassette types and wafer diameters:

 Conclusion

Wafer sorters must be designed with cassette and wafer size compatibility in mind to support the diverse needs of semiconductor fabs. Whether it is a 300mm FOUP in a state-of-the-art fab or an open cassette for 200mm production, the ability of a sorter to seamlessly handle multiple formats is central to maintaining productivity and flexibility.

Fortrend’s wafer sorter solutions are engineered for multi-cassette and multi-wafer size compatibility, offering fabs the versatility they need to transition between technologies while ensuring clean, efficient, and reliable wafer logistics.

Contact Fortrend to learn more about our customizable wafer sorter systems.