Stacked Image Sensor Via Coupling for Stable Signal and Power Lines
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Solution Overview
Problem
Existing solid-state imaging devices lack detailed examination of variations in electrical coupling methods for signal and power supply lines between stacked substrates, limiting performance improvements.
Innovation Solution
A solid-state imaging device with a three-layer stacked configuration, where substrates are bonded with a coupling structure featuring conductive vias or films to electrically couple wiring lines between the substrates, enhancing signal and power supply line connections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional electrical coupling methods (pad or TSV) are used for stacked substrates, then basic electrical connection is achieved, but device performance is limited due to lack of optimized coupling structures
Solution Approach 1:
The electrical coupling is segmented into multiple independent via structures (first vias, second vias, third vias) that can be independently designed and optimized for different signal and power requirements, allowing complex coupling needs to be broken down into manageable components
Solution Approach 2:
Different via structures are assigned to different locations and functions: first vias for signal lines, second vias for power supply lines, third vias for ground lines. Each via type can be optimized with appropriate dimensions, materials, and configurations suited to its specific electrical requirements
2Device complexity
If simple electrical coupling structures are used, then device complexity is reduced, but signal transmission quality and power supply stability deteriorate
Solution Approach 1:
Conductive films are introduced as intermediary elements within the via structures to ensure reliable electrical connection between stacked substrates. The conductive films fill and seal the via holes, providing stable electrical pathways that improve signal transmission quality and power supply stability
Solution Approach 2:
The via structures utilize composite material configurations combining conductive materials (for electrical connection) with insulating materials (for electrical isolation). This composite approach enables simultaneous optimization of electrical conductivity where needed and insulation where required, improving overall coupling performance
3Reliability
If detailed examination of coupling method variations is conducted, then appropriate structures for higher performance can be obtained, but manufacturing process complexity increases
Solution Approach 1:
The via structures are formed and conductive films are deposited in advance during the substrate manufacturing process, before final assembly. This preliminary formation of coupling structures allows optimization to be built into the manufacturing flow itself, reducing the need for complex post-assembly modifications
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 configuration improves the performance of the solid-state imaging device by allowing more appropriate electrical coupling, leading to better signal transmission and power supply stability, thus enhancing overall device performance.
Implementation Method 1
a via having a structure in which an electrically-conductive material is embedded in one through hole provided by penetrating at least the first substrate from a back surface side of the first substrate, or a structure in which a film including an electrically-conductive material is formed on an inner wall of the through hole
Data Source
AI summary
Provided is a solid-state imaging device that includes a first substrate which includes a first semiconductor substrate and a first multi-layered wiring layer that are stacked, a second substrate which includes a second semiconductor substrate and a second multi-layered wiring layer that are stacked, and a third substrate which includes a third semiconductor substrate and a third multi-layered wiring layer that are stacked. The solid-state imaging device further includes a first coupling structure for electrically coupling a circuit of the first substrate and a circuit of the second substrate to each other. The first coupling structure includes a via in which one through hole electrically couples a predetermined wiring line in the first multi-layered wiring layer, and a predetermined wiring line in the second multi-layered wiring layer or a predetermined wiring line in the third multi-layered wiring layer to each other.