Hybrid Bonded Die Stack Structure for Dense 3DIC Interconnects
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Solution Overview
Problem
The semiconductor industry faces challenges in achieving efficient integration and bonding of 3D integrated circuits (3DICs) due to complexities in interconnects and packaging, which affect integration density, speed, and bandwidth.
Innovation Solution
The method involves forming a die stack structure by bonding dies through a hybrid bonding structure, which includes a bonding insulating layer extending to contact with one interconnect structure, and using a dual damascene process for forming bonding metal layers. This approach allows for efficient face-to-face or face-to-back bonding of dies, enhancing integration density and performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional packaging methods are used for semiconductors, then manufacturing simplicity is maintained, but integration density and performance are limited
Solution Approach 1:
The patent transitions from conventional 2D planar packaging to 3D vertical stacking architecture. Multiple semiconductor dies are stacked vertically with interconnect structures extending through multiple layers, enabling three-dimensional integration. This dimensional change dramatically increases integration density by utilizing the vertical space above and below each die rather than only lateral expansion.
Solution Approach 2:
The patent implements a nested structure where multiple semiconductor dies are stacked one on top of another, with each die containing functional circuits and interconnect structures. The dies are nested vertically within a single package footprint, allowing multiple functional layers to be integrated within the same lateral area, similar to nested dolls.
2Speed
If interconnect lengths are increased to accommodate larger packages, then packaging area is increased, but signal speed and bandwidth deteriorate
Solution Approach 1:
The patent moves interconnect paths from lateral 2D routing to vertical 3D routing through the stack. TSVs (through-silicon vias) and vertical interconnect structures provide direct upward/downward signal paths between dies, dramatically shortening the distance signals must travel compared to lateral routing around the package perimeter.
Solution Approach 2:
The patent introduces intermediate redistribution layers and buffer structures between stacked dies that facilitate short-range vertical signal transmission. These intermediary interconnect structures act as mediators that enable efficient signal routing between adjacent dies in the stack, minimizing transmission distance and maintaining high signal integrity.
3Reliability
If bonding complexity is increased to achieve better bonding reliability, then bonding strength is improved, but manufacturing difficulty increases
Solution Approach 1:
The patent performs preliminary preparation of bonding surfaces and formation of bonding structures (such as metal pads, solder bumps, or direct bond interfaces) on each die before the stacking process. This preliminary action ensures that when dies are stacked, the bonding interfaces are already optimized for reliable attachment, reducing the complexity of the actual bonding operation.
Solution Approach 2:
The patent employs universal bonding structures and processes that can be applied across all dies in the stack using the same bonding methodology. By standardizing the bonding interface design and process parameters, the patent achieves consistent bonding reliability across multiple dies without requiring different bonding techniques for each interface, thereby simplifying the overall manufacturing process.
Data Source
AI summary
Provided is a die stack structure including a first die and a second die. The first die and the second die are bonded together through a hybrid bonding structure. A bonding insulating layer of the hybrid bonding structure extends to contact with one interconnect structure of the first die or the second die.