Direct Bond Interconnect (DBI®)
Highest interconnect density – enabling all elements on a chip to communicate with each other – integrating more functionality on a device – increasing the number of signal paths – maximizing performance and ultimately providing the most scalability available today and years into the future.
Ziptronix developed a method to enable silicon, III-V and other substrates to be bonded and electrically interconnected in a 3D fashion, to maximize the density of signal paths between chips used to interconnect transistors and other components. With DBI® technology, scalable 3D interconnections are used to vertically route interconnect between chips with dramatically reduced drive and ESD requirements. This capability enables an ultra-high density vertical interconnect between transistors, gates, and/or devices required to build scalable 3D ICs. This methodology leverages existing industry manufacturing infrastructure enabling compelling cost and performance factors to drive mainstream adoption of three-dimensional integrated circuits (3D ICs).
The industry faces significant design and cost barriers as two-dimensional devices migrate to process nodes below 65 nanometers (nm). It is increasingly difficult to scale technology in two-dimensional devices, as is evident by the increasing dominance of interconnect delay in limiting System-on-Chip (SoC) bandwidth and increasing difficulty in yielding mixed-signal ICs. DBI® technology extends scalability to these nodes by alleviating the interconnect delays with scalable 3D routing and allowing design partitioning in 3D.
DBI® can further minimize the need for TSVs and TDVs by offering solutions where interconnect happens at the bonded surface. TSV technologies used in current 3D IC integration methods can disrupt BEOL interconnect routing, consume excessive silicon, and hinder qualification. This technology provides the industry’s highest density of electrical connections for 3D ICs bonded in die-to-wafer or wafer-to-wafer scale methodology without requiring the etching and filling of vias through BEOL interconnect.
“DBI® can achieve over 100,000,000 electrical connections per square centimeter; a significant increase over the ~ 100,000 connections per square centimeter density achieved with through-die vias used in other 3D interconnect approaches.”
Competing 3D processes require large area exclusions that require valuable die area and result in the disruption of the BEOL interconnect stack of at least one IC layer in a 3D IC. DBI® allows for direct connections to be made between ICs as part of the bond process without disrupting and compromising the interconnect stack. With DBI®, 3D IC cost is minimized by avoiding design exclusions in the interconnect stack and delivering a vertical interconnections between IC layers in a 3D IC that can scale with the process node.
DBI® is an extension of the Ziptronix ZiBond®; direct bond technology that enables covalent, room temperature bonds between silicon oxide or nitride surfaces of each chip used in the 3D stacked structure. This breakthrough technology utilizes a chemo-mechanical polish to expose metal patterns embedded in the surface of each chip. When these patterns are aligned and bonded using the company’s bonding technology, the distortion and mis-alignment is minimized, as opposed to other bonding techniques that require heat and/or pressure as part of the bonding process that increase distortion and misalignment. The direct bond is characterized by a very high bond energy between the chip surfaces, which includes the metal patterns that form effective electrical connections between the chips. The low resistance of these electrical connections enables better power efficiency and reduces the overall power consumption of the 3D IC.
DBI® is also being considered by several manufacturers of next generation image sensors to directly connect control electronics and memory to the sensor devices. This can enable direct control of the individual pixel with extremely short connections. With Ziptronix’ Cu DBI® technologies, foundries are able to consider transferring the processing into existing fabrication facilities without creating incompatible processing challenges.