Hybrid Interconnect for Chip Stacking via Reflowed Solder Channels
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current semiconductor technologies face limitations in increasing circuit density due to physical constraints in two-dimensional integration, prompting the exploration of three-dimensional integrated circuits (3D ICs) to enhance component packing efficiency.
Innovation Solution
The method involves forming a chip stack with a substrate, contact pads, an adhesive layer, and semiconductor devices, where conductive channels are created by reflowing solder balls to establish electrical connections between stacked semiconductor devices, allowing for increased density without the need for through-substrate vias, and using an underfill for protection and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If three-dimensional IC stacking is implemented to increase circuit density, then component packing efficiency is improved, but manufacturing complexity and defect rates increase
Solution Approach 1:
The patent segments the interconnect structure into two distinct types: through-substrate vias for power/ground connections and hybrid interconnects with adhesive layers for signal connections. This segmentation allows different connection requirements to be met with optimized structures, reducing overall manufacturing complexity while maintaining high circuit density in the 3D stacked configuration.
Solution Approach 2:
The patent transitions from traditional 2D planar interconnects to 3D vertical stacking with hybrid interconnects that extend through the substrate thickness dimension. By utilizing the vertical dimension and creating adhesive layers at intermediate depths, the patent achieves higher circuit density without proportionally increasing manufacturing complexity, as the hybrid structure combines simple via formation with adhesive material deposition.
2Reliability
If through-substrate vias are used for electrical connections in stacked dies, then reliable power distribution is achieved, but manufacturing costs increase
Solution Approach 1:
The patent applies different interconnect qualities to different functional requirements: through-substrate vias are used specifically for power and ground connections where high reliability is critical, while hybrid interconnects with adhesive layers are used for signal connections where cost reduction is prioritized. This local differentiation optimizes the balance between reliability and manufacturing cost by not over-engineering all connections with the most expensive via structure.
Solution Approach 2:
The adhesive layer in the hybrid interconnect structure serves multiple functions: it provides electrical connection for signal paths, acts as a mechanical bonding layer between dies, and enables alignment tolerance compensation. This multi-functionality reduces the need for separate dedicated bonding processes, thereby lowering manufacturing costs while maintaining reliable power distribution through the specialized via structures.
3Quantity of substance
If smaller feature sizes are used to increase integration density, then more components can be integrated, but manufacturing precision requirements increase
Solution Approach 1:
The patent performs preliminary formation of the adhesive layer and hybrid interconnect structures before final die stacking and bonding. This preliminary action allows for pre-alignment and pre-positioning of interconnect elements, reducing the precision requirements during the final high-stakes bonding process. The adhesive layer is deposited and patterned in advance, creating a tolerance buffer that accommodates variations in die placement without compromising the final integration density.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enables higher circuit density without the costs associated with through-substrate vias, reduces defect rates through pre-testing of semiconductor devices, and provides reliable power distribution with larger bump sizes, leading to more efficient and cost-effective semiconductor packaging.
Implementation Method 1
conductive channels are created by reflowing solder balls to establish electrical connections between stacked semiconductor devices
Data Source
AI summary
Methods of packaging semiconductor devices and structures thereof are disclosed. In one embodiment, a method of packaging a semiconductor device includes providing a substrate, and adhering a first semiconductor device. Chip stacks are formed by providing a plurality of semiconductor devices and bonding them to the substrate and the first semiconductor device. At least one of the provided semiconductor devices is physically connected to both the substrate and the first semiconductor device it is stack on. Other semiconductor devices may stacked by forming conductive channels in the first semiconductor device, and placing the other semiconductor devices in physical contact with the first semiconductor device and the conductive channels.