The solution, called ‘TNCEL-W’, can inspect in bulk micro-LED chips less than 50 μm at the wafer process stage. The solution makes it possible to test and inspect micro-LEDs without direct contact with the chip. The solution is currently undergoing performance tests with Top Engineering’s customers, and it is hoped that it will hit the market by the end of 2021.
One of the biggest challenges concerned with the use of micro-LEDs for displays is the level of technology and skill required to undertake the stable transfer of the chips from the wafer to the display panel. OEMs are currently struggling to develop micro-LED products in bulk due to these chip transfer and bonding processes.
Defective chips leading to defective pixels on the displays is also a great challenge. There are around 100 million micro-LED chips required for an 8K television so identifying one defective chip is extremely difficult. According to LED Professional, even if the defect rate was 0.5%, 520,000 defective chips would need to repaired and this could take up to 144 hours.
Top Engineering’s TNCEL-W was developed to address these challenges. The solution can identify defective chips in advance before the micro-LEDs are transferred to the panel. According to the company, it is possible to minimize the inspection and damage to the micro-LED chip without direct contact with the chip while applying both the electrical and optical measurement methods used in the LED chip inspection. The inspection speed has also been greatly improved.