Imaging Device Dummy Wiring Potential Control
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Solution Overview
Problem
In solid-state imaging devices, the presence of wiring sections and dummy wiring sections can affect photoelectric conversion characteristics, leading to increased dark signal components and image defects like white voids, making it difficult to predict and suppress their influence on photoelectric conversion units.
Innovation Solution
A solid-state imaging device is designed with a semiconductor substrate featuring plural photoelectric conversion units, a peripheral circuit, and a dummy wiring section on the opposite side of the wiring section, which is not connected to the photoelectric conversion units or peripheral circuit, with a predetermined potential to stabilize and predict its influence.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If wiring sections are formed on the light receiving unit to connect photoelectric conversion units, then electrical connectivity is achieved, but photoelectric conversion characteristics are affected and dark signal components increase
Solution Approach 1:
The patent moves wiring sections from the light receiving unit surface to the back surface of the semiconductor substrate. This dimensional relocation allows wiring to be positioned in a different spatial plane, eliminating optical interference with incident light while maintaining electrical connectivity to photoelectric conversion units through vertical vias.
Solution Approach 2:
The patent introduces dummy wiring sections on the light receiving unit that replicate the optical blocking effect of actual wiring sections. These dummy wirings are positioned symmetrically to create optical balance, allowing signal processing to compensate for their effect while actual wiring causes minimal disturbance.
2Illumination intensity
If dummy wiring sections are formed to achieve optical symmetry, then optical characteristics are improved, but photoelectric conversion characteristics are still affected and influence becomes unpredictable
Solution Approach 1:
The patent connects dummy wiring sections to the same potential as adjacent actual wiring sections through via contacts. This equipotential connection ensures that both actual and dummy wirings exert identical electrical influence on photoelectric conversion units, making the total effect predictable and compensatable through signal processing.
3Reliability
If wiring sections are formed between adjacent photoelectric conversion units, then electrical connection is achieved, but image defects such as white voids occur
Solution Approach 1:
The patent relocates wiring sections from the front surface light receiving unit to the back surface of the semiconductor substrate. This positional change in a different dimension allows light to pass through the light receiving unit without encountering wiring obstructions, eliminating white void defects while maintaining electrical connectivity through vertical via structures.
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 suppresses the actual influence of the dummy wiring section on photoelectric conversion characteristics, reducing dark signal components and image defects, and makes the influence predictable, similar to that of other wiring sections, thereby improving image quality.
Implementation Method 1
plural photoelectric conversion units formed side by side on one surface of a semiconductor substrate to form a light receiving unit
Data Source
AI summary
A solid-state imaging device including a semiconductor substrate; plural photoelectric conversion units formed side by side on the semiconductor substrate to form a light receiving unit; a peripheral circuit formed in a portion on an outside of the light receiving unit on the semiconductor substrate; a wiring section formed on the light receiving unit and formed for connecting the plural photoelectric conversion units and the peripheral circuit; and a dummy wiring section formed on an opposite side of the wiring section for at least one photoelectric conversion unit among the plural photoelectric conversion units on the light receiving unit and formed for functioning as a non-connected wiring section not connected to the photoelectric conversion units and the peripheral circuit, wherein the dummy wiring section has a predetermined potential.