Leti, Intel look to quadruple hybrid bonding speeds
CEA-Leti in France has been working with Intel on a hybrid die-to-wafer process that could quadruple production speeds for chiplet-based packages.
The process developed with Intel explores another approach for highly precise alignment using the capillary forces of a water droplet. This uses a pick-and-place robot for rapid pre-alignment with a precision of more than 200 microns. The second step would be to finish the alignment process using the forces of capillarity in a water droplet, which is capable of aligning a die-to-wafer at 400nm.
This process is only in an exploratory phase and requires the development of specific equipment. Several key points must be validated such as the compatibility of copper and water.
However, the precision of alignment achieved would meet the demands of mounting future chiplets on substrates with a precision of 500nm. The use of a fast pick-and-place robot would open the way for a production rate of 2,000 chips per hour, more than four times faster than current industrial production speeds.
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CEA-Leti also recently completed an equipment collaboration with SET (Smart Equipment Technology) for a robotic direct hybrid bonding die-to-wafer process that combines precise alignment and high throughput.
The collaboration with SET focused on hybrid bonding between chips and wafers with copper and oxide surfaces. This scenario can be found for example in the case of AI chips that layer III-V materials such as LEDs and image sensors on silicon components such as memory and CMOS circuits.
The process has an alignment accuracy of under one micron process and is currently being used in CEA-Leti clean rooms.
The primary constraint was the need for an ultra-clean environment to avoid contamination. To improve throughput, researchers focused on how chips are cleaned after they are cut. They increased the speed of this costly step thanks to the development of an optimized cleaning strategy.