First, the wafer-to-wafer bonding was used to bond two ASIC wafers with TSVs. Then, the bonded wafer pair is thinned to expose the TSVs on one side, then singulated. The singulated die stacks are then bonded to an x-ray sensor wafer using die-to-wafer hybrid bonding. Subsequent thinning of the other side of the bonded wafer pair allows backside connections to the 3-layer assembly.
"Implementing DBI hybrid bonding enables us to design sophisticated combinations of sensors and readout electronics," said Ron Lipton, Staff Scientist, Fermilab. "By enabling vertical signals through stacked sensor, readout and processing layers, we can design large-scale arrays that are side-edge buttable with high fill factor."
"This is an advanced three-layer imaging chip manufactured using DBI hybrid bonding," said Paul Enquist, CTO, Ziptronix. "Electrical data shows that this approach achieves lower noise, higher bandwidth and higher gain due to lower capacitive load when compared with parts stacked using bumping. This increases the sensitivity of the 3D image sensors, making them ideal for use in high-end applications."
