Micro LED Verification Substrate for Rapid Defect Filtering

The transfer process is segmented into two distinct stages: first, mass transfer of all chips using a stamp to achieve high speed; second, individual transfer of only defective chips for replacement. This segmentation allows the system to benefit from both high-speed mass transfer and accurate defect filtering.

Verification of chip functionality is performed before the final transfer process. By pre-identifying defective chips through electrical testing on the wafer, the system can plan the replacement strategy in advance, ensuring that only necessary individual transfers are performed after mass transfer.

Instead of performing individual transfer on all chips, the system applies individual transfer only to the small subset of defective chips identified during verification. The majority of chips are transferred efficiently using mass transfer, thus achieving high overall speed while maintaining accurate defect filtering where needed.

The chip population is segmented into two groups: functional chips transferred via high-speed mass transfer, and defective chips requiring individual transfer. This segmentation minimizes the number of slow individual operations while ensuring complete defect filtering.

The verification process provides feedback on chip functionality before transfer. This feedback information is used to generate a transfer map that guides the subsequent replacement process, allowing the system to optimize the transfer strategy based on actual chip status rather than treating all chips uniformly.

By performing verification and creating a transfer plan before the actual transfer, the system prepares the optimal transfer strategy in advance. This preliminary action reduces the complexity of post-transfer defect removal by pre-identifying which chips need individual handling.