Solid-State Imaging Device Vertical Electrode Segmentation
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Solution Overview
Problem
Solid-state imaging devices with global shutter functions face challenges in maintaining mechanical strength while suppressing parasitic light sensitivity (PLS), as existing designs often compromise on either mechanical integrity or light blocking efficiency.
Innovation Solution
The design incorporates a semiconductor substrate with adjacent first and second vertical electrodes and a stepwise formation of light-blocking films, providing wider support for the photoelectric converter and effectively blocking light between the converter and charge accumulation section, thereby maintaining mechanical strength and reducing PLS.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single vertical electrode is used to support the photoelectric converter, then the device complexity is reduced, but the mechanical strength and support stability deteriorate
Solution Approach 1:
The single vertical electrode is segmented into multiple vertical electrodes (first vertical electrode and second vertical electrode) that are adjacently disposed. This segmentation provides wider support for the photoelectric converter, improving mechanical strength while maintaining a relatively simple overall structure.
2Ease of manufacture
If the second light-blocking film is formed in one step, then the manufacturing process is simpler, but the mechanical strength during formation is insufficient
Solution Approach 1:
The formation of the second light-blocking film is segmented into two steps: first forming a first light-blocking film, then forming a second light-blocking film. This stepwise formation provides intermediate support during the manufacturing process, maintaining mechanical strength while ultimately achieving the light-blocking function.
Solution Approach 2:
The first light-blocking film is formed as a preliminary structure before forming the complete second light-blocking film. This preliminary action provides mechanical support during the manufacturing process, preventing potential damage to the photoelectric converter.
3Device complexity
If the distance between vertical electrodes is large, then the device complexity is reduced, but the PLS suppression capability deteriorates
Solution Approach 1:
The vertical electrodes are adjacently disposed with minimal spacing, creating a localized dense structure that effectively blocks light from reaching the charge accumulation section. This local quality enhancement provides superior PLS suppression without significantly increasing overall device complexity.
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 supports the photoelectric converter more firmly and effectively suppresses PLS, ensuring both mechanical integrity and improved light-blocking efficiency, enhancing the overall performance of the solid-state imaging device.
Implementation Method 1
a first light-blocking film provided in a thickness direction of the semiconductor substrate on at least a portion of a periphery of the photoelectric converter; and a second light-blocking film provided in a surface direction of the semiconductor substrate between the photoelectric converter and the charge accumulation section
Data Source
AI summary
A solid-state imaging device includes: a semiconductor substrate having a light incident surface; a photoelectric converter for each of the pixels; a charge accumulation section for each of the pixels; a first transfer transistor; a wiring layer on side opposite to the light incident surface; a first vertical electrode and a second vertical electrode extending from the surface opposite to the light incident surface to the photoelectric converter; a first light-blocking film in a thickness direction of the semiconductor substrate on at least a portion of a periphery of the photoelectric converter; and a second light-blocking film in a surface direction of the semiconductor substrate between the photoelectric converter and the charge accumulation section. The first vertical electrode and the second vertical electrode are disposed adjacently with a distance therebetween, and the distance is a half or less of a length of one side of the pixel.