How Are Wafers Stored And Shipped

After completing all processes in the wafer fab, what are the special requirements for storage and transportation?

Is special environmental packaging required? Generally, wafers are stored in nitrogen cabinets supplied with high-purity nitrogen, and these cabinets can control humidity and temperature, maintaining humidity at 20-24°C and 30%-50% humidity. Specific conditions may vary depending on the site. For transportation, wafers are typically placed in wafer carriers, which are then placed in anti-static bags that are vacuum-sealed. These sealed bags containing the wafer carriers are then placed in boxes with cushioning materials for protection, typically done in a cleanroom environment. If possible, nitrogen can be generated within the transportation vehicle to create a controlled temperature and humidity environment. Other considerations include ensuring proper labeling for tracking purposes. What are the key factors to consider for wafer storage and transportation?

Cleanliness: Any gases or particles that may contaminate the wafers should be avoided, necessitating vacuum sealing or storage in high-purity nitrogen.

Temperature and humidity: Extreme temperature changes can alter wafer materials, while high humidity can cause surface moisture absorption and low humidity can increase static charge accumulation.

Physical protection: Wafers need protection from impacts and pressure during transportation, as external forces can easily cause breakage, requiring the use of cushioning materials for packaging.

Static electricity: Electrostatic discharge can damage chips, necessitating the use of anti-static packaging materials and applying anti-static treatment to the wafers during packaging.