Imaging Element Through-Electrode Structure for Low Reflection
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Solution Overview
Problem
Solid-state imaging devices with pixel arrangements of primary color filters suffer from interpolation processes that generate false colors, and existing back-illuminated imaging elements face challenges in applying high-temperature processes and transferring signal charges effectively across the semiconductor substrate.
Innovation Solution
An imaging element with a semiconductor substrate, a first photoelectric converter, a through electrode, and dielectric films of varying thicknesses is designed, where the first dielectric film is thicker on the surface and the second dielectric film is thinner on the side surface of the through hole, reducing light reflection and capacitance while enabling efficient signal charge transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a thick dielectric film is provided on the side surface of the through hole to suppress capacitance increase, then light reflection is reduced, but the film thickness cannot be uniformly thick without increasing capacitance
Solution Approach 1:
The patent applies local quality by providing a first dielectric film with greater thickness on the side surface of the through hole to suppress capacitance, while providing a second dielectric film with lesser thickness on the light receiving surface to minimize light reflection. This spatial differentiation of film thickness allows each region to optimize for its specific functional requirement.
Solution Approach 2:
The patent segments the dielectric film into two distinct parts: a first dielectric film portion on the side surface and a second dielectric film portion on the light receiving surface. This segmentation allows independent optimization of thickness for each portion, resolving the contradiction between capacitance suppression and light reflection reduction.
2Object-affected harmful factors
If the dielectric film thickness is increased to reduce light reflection, then sensitivity characteristics improve, but capacitance of the through electrode increases
Solution Approach 1:
The patent applies local quality by providing a first dielectric film with greater thickness on the side surface of the through hole to suppress capacitance, while providing a second dielectric film with lesser thickness on the light receiving surface to minimize light reflection. This spatial differentiation of film thickness allows each region to optimize for its specific functional requirement.
Solution Approach 2:
The patent segments the dielectric film into two distinct parts: a first dielectric film portion on the side surface and a second dielectric film portion on the light receiving surface. This segmentation allows independent optimization of thickness for each portion, resolving the contradiction between capacitance suppression and light reflection reduction.
3Productivity
If a through electrode is provided to transfer signal charges across the semiconductor substrate, then signal charge transfer efficiency improves, but capacitance increases due to dielectric film coverage
Solution Approach 1:
The patent applies local quality by providing a first dielectric film with greater thickness on the side surface of the through hole to suppress capacitance, while providing a second dielectric film with lesser thickness on the light receiving surface to minimize light reflection. This spatial differentiation of film thickness allows each region to optimize for its specific functional requirement.
Solution Approach 2:
The patent segments the dielectric film into two distinct parts: a first dielectric film portion on the side surface and a second dielectric film portion on the light receiving surface. This segmentation allows independent optimization of thickness for each portion, resolving the contradiction between capacitance suppression and light reflection reduction.
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 enhances sensitivity characteristics by minimizing light reflection and capacitance, allowing for high-sensitivity imaging without false colors and effective signal charge transfer across the semiconductor substrate.
Implementation Method 1
This reduces the reflection of incident light on the one surface of the semiconductor substrate
Implementation Method 2
The through electrode is electrically coupled to the first photoelectric converter. The through electrode penetrates the semiconductor substrate inside the through hole
Implementation Method 3
The first photoelectric converter is provided above the one surface of the semiconductor substrate
Data Source
AI summary
Provided is an imaging element that includes a semiconductor substrate, a first photoelectric converter, a through electrode, a first dielectric film, and a second dielectric film. The semiconductor substrate has one surface and another surface that are opposed to each other. The semiconductor substrate has a through hole penetrating between the one surface and the other surface. The first photoelectric converter is provided above the one surface of the semiconductor substrate. The through electrode is electrically coupled to the first photoelectric converter and penetrates the semiconductor substrate inside the through hole. The first dielectric film is provided on the one surface of the semiconductor substrate and has a first film thickness. The second dielectric film is provided on a side surface of the through hole and has a second film thickness. The second film thickness is less than the first film thickness.