Backside Bond Pad Trench Layout for Void-Free 3D IC Connections
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Solution Overview
Problem
In three-dimensional (3D) integrated circuits, the reduction of critical dimensions for backside through-substrate vias (BTSVs) leads to challenges in filling holes with conductive material, resulting in incomplete filling and void formation, which compromises the reliability of electrical connections between bond pad layers and interconnect structures.
Innovation Solution
A bond pad structure extending through a trench in the substrate from the backside to the frontside, directly contacting underlying interconnect structures, eliminates the need for BTSVs by utilizing a trench with a large critical dimension, ensuring reliable electrical connections and reducing defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the critical dimension of backside through-substrate vias is reduced to increase integration density, then more components can be integrated into a given area, but incomplete filling and void formation occur compromising connection reliability
Solution Approach 1:
The patent changes the critical dimension parameter from small (BTSV) to large (trench), transforming the filling process outcomes. The trench structure with larger critical dimension enables complete conductive material filling without voids, resolving the reliability issue while maintaining integration density through alternative structural design
Solution Approach 2:
The patent extracts the problematic BTSV structure and replaces it with a trench structure. By removing the through-substrate via approach and substituting it with a trench-based bond pad structure, the invention eliminates the void formation issue while achieving the same electrical connection function
2Productivity
If the critical dimension of backside through-substrate vias is reduced to increase integration density, then more components can be integrated into a given area, but the filling process becomes difficult resulting in defects
Solution Approach 1:
The patent changes the critical dimension parameter from small (BTSV) to large (trench), transforming the filling process outcomes. The trench structure with larger critical dimension enables complete conductive material filling without voids, resolving the reliability issue while maintaining integration density through alternative structural design
Solution Approach 2:
Instead of reducing the size of through-substrate vias to increase density, the patent inverts the approach by using a larger trench structure that achieves density through different spatial arrangement and contact geometry, making the filling process easier and defect-free
3Reliability
If a trench structure with large critical dimension is used instead of BTSVs, then voids and defects are eliminated improving connection reliability, but the device structure becomes more complex
Solution Approach 1:
The patent merges the bond pad structure with the trench structure, creating an integrated design where the bond pad extends into the trench and contacts multiple interconnect conductive structures. This consolidation achieves reliable connections through a unified structure rather than separate components
Solution Approach 2:
The trench structure serves multiple functions: it provides mechanical support, enables electrical connection to multiple interconnect structures, and facilitates complete conductive material filling. This multi-functionality reduces the need for additional specialized structures, offsetting the apparent complexity increase
Data Source
AI summary
In some embodiments, the present disclosure relates to a device that includes an interconnect structure arranged on a frontside of a substrate. The interconnect structure includes interconnect conductive structures embedded within interconnect dielectric layers. A trench extends completely through the substrate to expose multiples ones of the interconnect conductive structures. A bond pad structure is arranged on a backside of the substrate and extends through the trench of the substrate to contact the multiple ones of the interconnect conductive structures. A bonding structure is arranged on the backside of the substrate and electrically contacts the bond pad structure.