Pixel Trench Light Shielding for Optical Black Region Isolation
Solution Overview
Problem
In solid-state imaging devices, incident light from the effective pixel region can pass through and enter the optical black pixel region, requiring a significant expansion of the optical black pixel region and an increase in manufacturing costs, or a reduction in the effective pixel region.
Innovation Solution
A solid-state imaging device with a pixel separation portion featuring trench portions in a grid pattern, where a specific straight groove portion at the boundary between the effective and optical black pixel regions has a different shape and includes a light shielding material, effectively weakening incident light that enters the optical black pixel region.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the optical black pixel region is expanded to sufficiently separate OPB pixels from the boundary, then the reference signal acquisition is improved, but the chip area is expanded and manufacturing cost is increased
Solution Approach 1:
The pixel separation portion is divided into multiple straight groove portions (first, second, and third straight groove portions) with different shapes and light shielding material configurations. This segmentation allows different regions to serve different functions: the first straight groove portion at the boundary effectively blocks incident light from entering the optical black pixel region, while the other groove portions maintain standard pixel separation, thereby reducing the required expansion of the optical black pixel region.
Solution Approach 2:
The light shielding material is selectively embedded only in the first straight groove portion at the boundary between the effective pixel region and the optical black pixel region, rather than uniformly in all groove portions. This local application of light shielding material provides targeted light blocking where it is most needed, effectively preventing incident light from reaching the optical black pixel region while minimizing the overall area expansion required.
2Reliability
If the optical black pixel region is expanded to sufficiently separate OPB pixels from the boundary, then the reference signal acquisition is improved, but the manufacturing cost is increased
Solution Approach 1:
The pixel separation portion is divided into multiple straight groove portions (first, second, and third straight groove portions) with different shapes and light shielding material configurations. This segmentation allows different regions to serve different functions: the first straight groove portion at the boundary effectively blocks incident light from entering the optical black pixel region, while the other groove portions maintain standard pixel separation, thereby reducing the required expansion of the optical black pixel region.
Solution Approach 2:
The light shielding material is selectively embedded only in the first straight groove portion at the boundary between the effective pixel region and the optical black pixel region, rather than uniformly in all groove portions. This local application of light shielding material provides targeted light blocking where it is most needed, effectively preventing incident light from reaching the optical black pixel region while minimizing the overall area expansion required.
3Object-affected harmful factors
If ineffective pixels are arranged between the effective pixel region and OPB pixels to block incident light, then light blocking is improved, but the OPB pixel region is expanded and effective pixel region is reduced
Solution Approach 1:
The first straight groove portion filled with light shielding material serves as an intermediary light-blocking structure between the effective pixel region and the optical black pixel region. This groove portion acts as a mediator that intercepts incident light before it can reach the optical black pixel region, replacing the need for multiple rows of ineffective pixels and thereby preserving the effective pixel region area.
Solution Approach 2:
The shape of the first straight groove portion is specifically designed to be different from the other straight groove portions, with dimensions and configuration optimized for light blocking at the boundary. This parameter change in groove shape and light shielding material embedding creates an effective light barrier that reduces the space needed for light blocking 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 reduces the number of ineffective pixels needed between the effective and optical black pixel regions, minimizing the expansion of the optical black pixel region and maintaining the chip area, thereby reducing manufacturing costs and potentially expanding the effective pixel region.
Implementation Method 1
a light shielding material is embedded in the specific straight groove portion
Data Source
AI summary
A solid-state imaging device capable of weakening incident light that passes through an effective pixel region and enters an optical black pixel region. Among a plurality of straight groove portions constituting a trench portion, a first straight groove portion is formed at a boundary between an effective pixel region and an optical black pixel region (OPB pixel region), a plurality of second straight groove portions are formed in the OPB pixel region and parallel to the boundary in a plan view, and a third straight groove portion is formed between photoelectric conversion units in the effective pixel region, a specific straight groove portion, the specific straight groove portion being the first groove portion and/or being one or more of the plurality of second straight groove portions, has a different shape from the third straight groove portion, and a light shielding material is embedded in the specific straight groove portion.