Influences of Chip Shape on Scaling in Chip-on-Wafer Hybrid Bonding

Abstract

This study investigated the influences of chip warpage and thickness on scaling in chip-on-wafer hybrid bonding. Scaling, a key bonding misalignment parameter, depends on the bonding process and substrate properties. Effective control of scaling in crucial for interconnecting Cu-pads with finer pitch. Scaling was induced by pre-stretching the incoming chip prior to bonding and during bond wave propagation. A warped chip was deformed under the film stress, thereby influencing scaling. Thinner chips exhibited greater stretch, resulting in significant impact. In addition, deformation occurred during bond wave propagation when bonding with a round bonding head, which also influenced scaling. The extent of deformation was observed to depend on the chip thickness.

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