Hybrid Bonded Semiconductor Devices for Multi-Wafer Stacking
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Solution Overview
Problem
The semiconductor industry faces challenges in achieving efficient multi-wafer stacking with smaller form factors and lower power consumption, as existing bonding techniques are limited in process-time effectiveness and inter-wafer electrical joint performance.
Innovation Solution
The use of face-to-face and back-to-back hybrid bonding technology for multi-wafer stacking, which involves forming bonding connectors on both sides of semiconductor devices and using hybrid bond pads to create vertical electrical connections without requiring through-vias, allowing for efficient stacking and reduced manufacturing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional bonding techniques are used for multi-wafer stacking, then manufacturing process is simpler, but process-time effectiveness and inter-wafer electrical joint performance are limited
Solution Approach 1:
The bonding process is segmented into two distinct phases: a first bonding phase that forms initial bonding connectors between wafers, and a second bonding phase that forms additional bonding connectors. This segmentation allows each phase to be optimized independently, improving overall process-time effectiveness while ensuring reliable electrical joints through the cumulative effect of multiple bonding stages.
Solution Approach 2:
The first bonding phase performs preliminary bonding actions to establish initial electrical connections between wafers before the second bonding phase. This preliminary action ensures that essential electrical joints are formed early, improving reliability while the subsequent second phase enhances process-time effectiveness by completing additional bonding operations efficiently.
2Reliability
If through-vias are used for vertical electrical connections, then electrical joint performance is achieved, but manufacturing complexity and cost increase
Solution Approach 1:
The invention extracts the essential function of through-vias (providing vertical electrical connections) and replaces it with bonding connectors formed through a two-phase bonding process. This eliminates the need for complex through-via fabrication while maintaining electrical joint performance, thereby reducing manufacturing complexity and cost.
Solution Approach 2:
Bonding connectors serve as intermediary structures that provide vertical electrical connections between stacked wafers without requiring through-vias. These connectors are formed through controlled bonding phases and act as mediators for electrical signal transmission, simplifying the manufacturing process while maintaining electrical performance.
3Volume of moving object
If multi-wafer stacking is implemented to reduce form factor, then device size is reduced, but bonding process complexity increases
Solution Approach 1:
The bonding process for multi-wafer stacking is segmented into two phases, where the first phase forms initial bonding connectors and the second phase forms additional bonding connectors. This segmentation simplifies the overall process by breaking down complex multi-wafer bonding into manageable stages, reducing bonding process complexity while enabling effective multi-wafer stacking for reduced form factor.
Solution Approach 2:
The first bonding phase performs preliminary bonding to establish essential connections before subsequent stacking operations. This preliminary action simplifies the overall multi-wafer stacking process by preparing wafers in advance, making the subsequent bonding operations more straightforward and reducing overall process complexity.
Data Source
AI summary
Semiconductor devices and methods of manufacture thereof are disclosed. In some embodiments, a semiconductor device includes a first hybrid bonded device including a first device and a second device hybrid bonded face-to-face to the first device. The first device includes a first substrate having first bonding connectors and a first bonding layer disposed on a surface thereof. A second hybrid bonded device is bonded back-to-back to the first hybrid bonded device. The second hybrid bonded device includes a third device and a fourth device hybrid bonded face-to-face to the third device. The third device includes a second substrate having second bonding connectors and a second bonding layer disposed on a surface. The second bonding connectors of the third device are coupled to the first bonding connectors of the first device, and the second bonding layer of the third device is coupled to the first bonding layer of the first device.