Light Sensing Device Filter Element Width Optimization
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Solution Overview
Problem
Current image sensor devices face challenges in achieving improved performance and reliability due to limitations in geometric scaling and material advancements, which affect the efficiency and cost-effectiveness of semiconductor integrated circuits.
Innovation Solution
The development of a light sensing device with a backside illuminated (BSI) or front side illuminated (FSI) image sensor design, incorporating a semiconductor substrate with isolation structures, transistors, and a confinement grid for forming filter elements, which enhances light detection and reduces optical reflection through anti-reflection coatings and light shielding layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If geometric size is reduced to increase functional density, then productivity and cost-effectiveness improve, but manufacturing precision and reliability become more difficult to maintain
Solution Approach 1:
The device is divided into distinct functional regions including pixel regions with photodetectors, transistor regions with source/drain structures, and isolation regions. This segmentation allows each region to be optimized independently for its specific function while maintaining overall device performance despite geometric scaling
Solution Approach 2:
Different regions of the semiconductor substrate are doped with different doping types and concentrations to create locally optimized electrical properties. For example, n-type doping in photodetector regions versus p-type doping in transistor regions, ensuring each area has the precise electrical characteristics needed for its function
2Productivity
If geometric size is reduced to increase functional density, then productivity and cost-effectiveness improve, but device reliability deteriorates
Solution Approach 1:
Shallow trench isolation structures are formed beforehand to define and electrically isolate adjacent pixel regions and transistor regions before subsequent processing steps. This preliminary isolation prevents electrical interference and ensures reliable operation of closely spaced components despite reduced geometric dimensions
Solution Approach 2:
The shallow trench isolation structures act as intermediary elements between adjacent active regions, providing electrical isolation and preventing unwanted charge carrier leakage. These isolation structures mediate the interaction between neighboring pixels and transistors, ensuring reliable device operation at scaled dimensions
3Productivity
If functional density is increased, then productivity improves, but optical performance and light detection efficiency worsen
Solution Approach 1:
The photodetector structures extend vertically through multiple layers including the semiconductor substrate and overlying dielectric layers. This vertical dimensionality allows increased light absorption path length and improved detection efficiency without increasing the horizontal footprint, thereby maintaining high functional density
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 improves the light sensing device's performance by enhancing light detection efficiency, reducing optical reflection, and maintaining reliable operation, thereby addressing the limitations of existing image sensor technologies.
Implementation Method 1
anti-reflection coatings and light shielding layers
Implementation Method 2
anti-reflection coatings and light shielding layers
Data Source
AI summary
A light sensing device is provided. The light sensing device includes a semiconductor substrate and a light sensing region in the semiconductor substrate. The light sensing device also includes a filter element over the light sensing region and a light shielding element over the semiconductor substrate and beside the filter element. The light sensing device further includes a dielectric element over the light shielding element and beside the filter element. A top of the light shielding element and a bottom of the dielectric element have different widths.