Purging the pods and replacing the highly variable ambient with clean dry air or nitrogen helps to eliminate the potentially damaging effects of AMCs. There is no clear way to clean a copper-contaminated FEOL wet sink, potentially rendering the tool inoperable for an indefinite period of time. In order to prevent cross-contamination, it is crucial to prevent BEOL wafers from entering an FEOL tool. This strategy can be easily implemented in any SMIF manufacturing environment because of the adaptability of existing pods and load ports. As shown in Figure 5, this mechanical interlock system makes it physically impossible for a BEOL pod to fit onto a FEOL load port, preventing the pod from opening and the wafers from being processed.
Correct placement allows a wafer carrier to sit properly on a load port, enabling wafer processing.
A similar mechanical interlock scheme for 200-mm SMIF pods is available. Illustration courtesy of Semi. Incorrect pin and info pad placement interferes with carrier placement and prevents wafer processing, while correct placement allows a wafer carrier to sit properly on a load port, enabling wafer processing. Illustration courtesy of Semi. The FEOL-BEOL strategy provides an effective physical safeguard to ensure copper processing integrity.