Variable-Pitch Bond Structure for Flat Stacked IC Bonding
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing stacked IC devices face issues with non-bond regions, increased design complexity, and fabrication costs due to uniform pitch conductive bond pads leading to height variations and reduced bonding adhesion between chips.
Innovation Solution
Implementing a bond structure with conductive bond pads arranged in different regions with varying pitches, where the first region has a higher density and smaller pitch directly under photodetectors, and the second region has a lower density and larger pitch, reducing the number of conductive structures and ensuring a flat bonding surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If uniform pitch conductive bond pads are used across the entire bond structure, then fabrication is simplified, but height variations occur leading to non-bond regions and reduced bonding adhesion
Solution Approach 1:
The bond structure employs different pitch values in different regions: a first pitch in a first region and a second pitch in a second region. This local differentiation allows the bond pads to compensate for height variations caused by underlying interconnect structures, ensuring uniform bonding surfaces across the entire chip while maintaining fabrication simplicity through a systematic regional approach.
2Device complexity
If uniform pitch conductive bond pads are used across the entire bond structure, then design is simplified, but non-bond regions increase reducing device yield
Solution Approach 1:
The patent divides the bond structure into multiple regions with different pitch characteristics. The first region has a first pitch optimized for areas with certain height variations, while the second region has a second pitch optimized for areas with different height characteristics. This regional optimization eliminates non-bond regions and improves device yield without requiring overly complex design methodologies.
3Productivity
If higher density bond pads with smaller pitch are used under photodetectors, then transmission efficiency improves, but the number of conductive structures increases raising fabrication costs
Solution Approach 1:
The bond structure implements a first pitch in a first region that is optimized for high transmission efficiency areas (such as under photodetectors), and a second pitch in a second region that reduces the overall number of conductive structures. This localized optimization ensures high performance where needed while reducing complexity and fabrication costs in other areas.
Solution Approach 2:
The bond structure is segmented into multiple regions with different pitch characteristics. This segmentation allows the design to optimize transmission efficiency in critical regions while reducing the number of conductive structures in non-critical regions, thereby balancing performance requirements with fabrication cost constraints.
Data Source
AI summary
Various embodiments of the present disclosure are directed towards a device including an interconnect structure over a substrate. A bond structure is over the interconnect structure. The bond structure includes a first plurality of conductive bond pads disposed in a first region and a second plurality of conductive bond pads disposed in a second region. The second region is adjacent to at least one side of the first region. A first pitch of the first plurality of conductive bond pads is less than a second pitch of the second plurality of conductive bond pads.