Edge Ring Rotational Pre-Alignment for Precise Wafer Support Placement

The system performs preliminary rotational alignment of the edge ring on the carrier plate before transfer to the substrate support. The substrate aligner rotates the carrier plate with the edge ring to the correct orientation, and imaging devices detect alignment features to ensure proper positioning. This preliminary action ensures that when the robot transfers the edge ring, the alignment is already established, resolving the contradiction between automated transfer efficiency and alignment precision.

The substrate aligner and imaging devices are designed to handle both substrates and edge rings with the same basic mechanism. The aligner can rotate different objects, and the imaging devices can detect various alignment features (notches, flat regions, marks) on different objects. This multi-functionality allows the system to protect substrate supports using edge rings without requiring entirely separate alignment mechanisms, thus limiting the increase in device complexity while maintaining reliability.

The system uses imaging devices as intermediaries to detect alignment features on edge rings and substrates. These imaging devices capture images of features such as notches, flat regions, or marks, and the controller processes these images to determine rotational position. This intermediary detection method provides high measurement precision without requiring direct mechanical measurement mechanisms, thus limiting the increase in device complexity while achieving accurate detection.