Image Sensor Via-Trench Pad Structure for Reliable Interconnects
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Solution Overview
Problem
Current image sensors face challenges in enhancing product reliability, particularly in the design and integration of substrates, wiring structures, and pad patterns, which affect the overall performance and efficiency of light reception and signal processing.
Innovation Solution
The proposed image sensor design includes a first and second substrate with specific wiring structures, via trenches, and pad patterns, which are integrated to improve light reception and signal processing by enhancing electrical connectivity and reducing exposure to external factors, thereby increasing product reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a via trench penetrates the first substrate and first wiring structure to connect to the second wiring, then electrical connectivity is improved, but the substrate and wiring structures are exposed to external factors reducing reliability
Solution Approach 1:
The patent introduces a pad pattern as an intermediary element that fills the via trench and mediates between the first substrate/wiring structure and the second wiring structure. This pad pattern protects the exposed wiring from external factors while maintaining electrical connectivity, thus resolving the contradiction between improved connectivity and reduced exposure to harmful factors.
2Reliability
If the second wiring structure is exposed in the via trench, then electrical connectivity is improved, but the risk of defects increases
Solution Approach 1:
The pad pattern serves as a protective intermediary that covers the exposed second wiring structure within the via trench. This intermediary structure reduces the risk of defects by protecting the wiring from environmental factors and mechanical damage, while still allowing electrical signals to pass through to the second substrate.
3Reliability
If a through via structure extends along the via trench, then electrical connectivity between substrates is improved, but the complexity of the wiring structure increases
Solution Approach 1:
The patent merges the through via structure with the pad pattern by having the pad pattern fill and integrate with the via trench region. This combining approach simplifies the overall structure by reducing the number of separate components and manufacturing steps, thereby reducing complexity while maintaining the electrical connectivity function.
Data Source
AI summary
An image sensor includes a first substrate including a first surface and a second surface opposite to the first surface, a first wiring structure provided on the second surface of the first substrate, the first wiring structure including a first wiring and a first inter-wiring insulating film, a second substrate including a third surface facing the second surface of the first substrate, and a fourth surface opposite to the third surface, a second wiring structure provided on the third surface of the second substrate, the second wiring structure including a second wiring and a second inter-wiring insulating film, a via trench penetrating the first substrate and the first wiring structure, a through via structure extending along the via trench and connected to the second wiring, and a pad pattern provided on the through via.