Image Sensor Shielding Part and Anti-Reflection Layer
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Solution Overview
Problem
Current image sensors face challenges in achieving high density and reduced pixel size while effectively preventing oblique light from entering the photocharge storage, which affects image quality and efficiency.
Innovation Solution
The image sensor design incorporates a shielding part with protrusions and an anti-reflection layer to prevent oblique light from reaching the photocharge storage, featuring a substrate with specific separation patterns and an anti-reflection layer structure that covers the photocharge storage and extends over the photoelectric conversion part, ensuring efficient light management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If the pixel size is reduced to achieve high density, then the image sensor can achieve higher resolution and compactness, but it becomes difficult to effectively prevent oblique light from entering the photocharge storage
Solution Approach 1:
The shielding part is divided into multiple protrusions (first protrusion, second protrusion, third protrusion) that are distributed at different positions and orientations. Each protrusion segments the oblique light paths from different directions, preventing them from reaching the photocharge storage. This segmented approach allows effective light blocking in reduced pixel sizes without requiring a single large shielding structure.
Solution Approach 2:
The anti-reflection layer is configured with an overhang structure that locally extends over the photocharge storage region. This local quality enhancement provides targeted protection against oblique light at critical areas while maintaining the overall compact pixel structure. The overhang creates a localized shadow region that blocks oblique light paths without increasing the overall pixel footprint.
2Loss of energy
If a shielding part is added to block oblique light, then light conversion efficiency is improved, but the device structure becomes more complex
Solution Approach 1:
The shielding part is integrated with the separation patterns that already exist in the pixel structure. The first protrusion is formed along the first separation pattern, and the second protrusion is formed along the second separation pattern, merging the shielding function with the existing pixel division structure. This reduces overall device complexity by combining multiple functions into unified structures.
Solution Approach 2:
The separation patterns serve dual purposes: they define the pixel boundaries and simultaneously serve as the basis for forming the shielding protrusions. The anti-reflection layer also serves multiple functions by providing both optical anti-reflection properties and structural overhang for light blocking. This multi-functionality reduces the need for separate dedicated shielding structures.
3Object-affected harmful factors
If the anti-reflection layer is extended to cover the photocharge storage, then oblique light is blocked effectively, but the manufacturing precision requirements increase
Solution Approach 1:
The anti-reflection layer is formed with an overhang structure that extends over the photocharge storage region before the final pixel structures are completed. This preliminary action of creating the overhang provides a pre-positioned light-blocking feature that simplifies subsequent alignment processes. The overhang is formed in advance to guide the positioning of other pixel components.
Solution Approach 2:
The anti-reflection layer's overhang structure self-aligns with the photocharge storage region through its geometric configuration. The protrusions and overhangs are designed to work together where the anti-reflection layer naturally positions itself relative to the shielding structures, reducing the need for high-precision external alignment processes.
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 design enhances image quality by preventing light from entering the photocharge storage, improving the efficiency of light conversion and reducing noise, thereby achieving higher image resolution and performance.
Implementation Method 1
an anti-reflection layer between the shielding part and the substrate, the anti-reflection layer having an overhang structure between the first protrusion and the extension
Implementation Method 2
an image sensor includes a substrate with a unit pixel defined by a first separation pattern, a photoelectric conversion part in the substrate
Data Source
AI summary
An image sensor includes a substrate with a unit pixel defined by a first separation pattern, a photoelectric conversion part in the substrate, a photocharge storage in the substrate, the photocharge storage being adjacent to the photoelectric conversion part, a second separation pattern between the photoelectric conversion part and the photocharge storage, a shielding part on a bottom surface of the substrate to cover the photocharge storage, the shielding part including a first protrusion extending into the substrate and toward the first separation pattern, and an extension extending from the first protrusion to cover the bottom surface of the substrate; and an anti-reflection layer between the shielding part and the substrate, the anti-reflection layer having an overhang structure between the first protrusion and the extension.