Through-Electrode Image Sensor Structure for Reduced Substrate Capacitance
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Solution Overview
Problem
Existing solid-state imaging devices face challenges in enhancing characteristics such as conversion efficiency due to the limitations of conductive plugs in transferring charges between photoelectric conversion elements and the semiconductor substrate, particularly in longitudinal stereoscopic types.
Innovation Solution
The implementation of a through electrode coupled with a separation groove and dielectric layers to reduce capacitance between the through electrode and the semiconductor substrate, allowing for efficient charge transfer and improved conversion efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conductive plug is used to transfer charges from photoelectric conversion elements to the semiconductor substrate, then charge transfer is enabled, but conversion efficiency is insufficient due to capacitance between the conductive plug and substrate
Solution Approach 1:
The patent introduces a dielectric layer as an intermediary substance between the through electrode and semiconductor substrate. This dielectric layer acts as a mediator that electrically isolates the conductive through electrode from the substrate, thereby eliminating parasitic capacitance while maintaining the charge transfer function through the electrode itself
Solution Approach 2:
The patent segments the electrical connection path by separating the conductive through electrode from direct contact with the semiconductor substrate. The dielectric layer creates a physical and electrical segmentation that divides the charge transfer function (performed by the through electrode) from the substrate interaction, eliminating the harmful capacitance effect
2Reliability
If the through electrode is directly coupled to the semiconductor substrate, then charge transfer is achieved, but dark currents increase due to capacitance effects
Solution Approach 1:
The dielectric layer serves as an intermediary that blocks the generation of dark currents by preventing direct capacitive coupling between the through electrode and semiconductor substrate. This intermediary layer eliminates the parasitic effects that would otherwise generate unwanted dark current signals
Solution Approach 2:
The patent converts the potentially harmful direct contact between electrode and substrate into a beneficial configuration by introducing the dielectric layer. This transforms the structure from one that generates harmful capacitance and dark currents into one that eliminates these harmful effects while preserving essential charge transfer functionality
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 charge transfer and conversion efficiency, reduces dark currents, and improves the reliability of the imaging process by effectively separating the through electrode from the semiconductor substrate, thereby improving the overall performance of the solid-state imaging device.
Implementation Method 1
charges generated in the photoelectric conversion element on the side of the first surface of the semiconductor substrate are transferred to the side of the second surface of the semiconductor substrate via the through electrode
Implementation Method 2
a dielectric layer embedded in the separation groove, and having insulation properties
Implementation Method 3
one or more photoelectric conversion elements provided on side of a first surface of a semiconductor substrate
Data Source
AI summary
There is provided a solid-state imaging device including: one or more photoelectric conversion elements provided on side of a first surface of a semiconductor substrate; a through electrode coupled to the one or more photoelectric conversion elements, and provided between the first surface and a second surface of the semiconductor substrate; and an amplifier transistor and a floating diffusion provided on the second surface of the semiconductor substrate, in which the one or more photoelectric conversion elements are coupled to a gate of the amplifier transistor and the floating diffusion via the through electrode.