Backside Bond Pad Trench Layout for Void-Free 3D IC Interconnects
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Solution Overview
Problem
The challenge in 3D integrated circuits (ICs) is the formation of reliable electrical connections between bond pad layers on different substrates, particularly due to the difficulty in filling conductive material into BTSVs with large aspect ratios, leading to voids and poor connections.
Innovation Solution
A bond pad structure is designed to extend through a trench in the substrate, directly contacting multiple interconnect conductive structures, thereby eliminating the need for backside through-substrate vias (BTSVs). This design ensures a more reliable electrical connection by maintaining a wide trench with a large critical dimension, facilitating easier deposition of the conductive material.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If backside through-substrate vias (BTSVs) with large aspect ratios are used to connect bond pad layers, then vertical electrical connection is achieved, but manufacturing defects occur due to difficulty in filling conductive material
Solution Approach 1:
The patent divides the single deep BSV into multiple shallower vias by segmenting the conductive path. The bond pad structure extends through a trench to contact multiple interconnect conductive structures at different depths, breaking the single long via into several shorter segments that are easier to fill with conductive material without voids
Solution Approach 2:
The patent transitions from a single vertical via approach to a multi-dimensional contact structure. The bond pad structure extends in the vertical direction through the trench while also making lateral contacts to multiple interconnect conductive structures, utilizing both vertical and lateral dimensions to achieve reliable connections
2Productivity
If minimum feature sizes are reduced to increase integration density, then more components can be integrated, but manufacturing precision requirements increase
Solution Approach 1:
The patent employs a nested structure where the bond pad structure is positioned within the trench and extends to contact multiple interconnect conductive structures. This nested arrangement allows compact integration of multiple connection points within a confined area, increasing integration density while maintaining manufacturable feature dimensions
3Ease of manufacture
If trench width is maintained large for easier material deposition, then manufacturing ease improves, but substrate area for other components decreases
Solution Approach 1:
The patent applies local quality by creating a trench with sufficient width only at the specific location where conductive material deposition is needed, while the rest of the substrate maintains its full area for other components. The trench is localized to the bond pad region, allowing easy material deposition where required without sacrificing overall substrate area
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.