Image Sensor Polarizer Trench Structure Light Sensitivity

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Solution Overview

Problem

Current image sensors face challenges in enhancing light sensitivity and polarization sensing capabilities, particularly in achieving high light absorption rates and efficient polarization state adjustment.

Innovation Solution

The image sensor design incorporates a polarizer with a lower structure featuring trenches and protruding patterns on a substrate, which increases light scattering and absorption, and includes upper patterns with different refractive indices to adjust polarization and wavelength, integrated with a photoelectric conversion region and device isolation patterns.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a conventional polarizer structure is used, then the device complexity is low, but the light absorption rate and sensitivity are insufficient

Engineering Contradiction:

Improvelight sensitivityVSAvoidpolarizer structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The polarizer is divided into multiple functional layers: a lower structure with trenches for light scattering, intermediate insulating patterns, and upper patterns with specific refractive indices. This segmentation allows each layer to perform its specific function optimally, improving overall light absorption and polarization sensitivity while maintaining manageable complexity through modular design

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The lower structure introduces vertical dimensionality with trenches recessed from the first surface toward the photoelectric conversion region. This three-dimensional structure increases the optical path length and light scattering opportunities, significantly improving light absorption efficiency compared to conventional two-dimensional polarizer structures

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Reliability

If the lower structure with trenches is added to increase light scattering, then light absorption improves, but manufacturing complexity increases

Engineering Contradiction:

Improvelight absorption rateVSAvoidpolarizer fabrication

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The manufacturing process merges multiple steps into integrated sequences: trenches are formed and filled with insulating material in a combined process, and upper patterns are formed through integrated lithography and deposition steps. This merging reduces the total number of separate manufacturing steps while achieving the complex multi-layer structure, improving ease of manufacture

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The lower insulating patterns automatically serve dual functions: they electrically isolate the conductive upper patterns from the substrate while simultaneously filling the trench spaces to maintain structural integrity. This self-service property eliminates the need for additional dedicated isolation layers, simplifying the manufacturing process

Inventive Principle:

Principle #25Self-service

3Adaptability or versatility

If upper patterns with different refractive indices are used, then polarization adjustment capability improves, but device complexity increases

Engineering Contradiction:

Improvepolarization adjustmentVSAvoidpolarizer structure

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

Different regions of the polarizer structure use materials with specifically tailored refractive indices: the lower structure uses one material property set for scattering, while the upper patterns use different materials optimized for polarization control at specific wavelengths. This local quality differentiation enables precise polarization adjustment capability while keeping each local region's function simple and well-defined

Inventive Principle:

Principle #3Local quality

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 light sensitivity and allows for effective polarization sensing, particularly for infrared light, by increasing light absorption and enabling easy manufacturing processes.

Implementation Method 1

a lower structure comprising at least one trench recessed from the first surface of the substrate toward the photoelectric conversion region

Methodology Applied

Scientific EffectLight scattering: Scattering

Implementation Method 2

increases light scattering and absorption

Methodology Applied

Scientific EffectLight absorption: Absorption (EM radiation)

Implementation Method 3

upper patterns provided on the lower structure and spaced apart from each other in a first direction parallel to the first surface

Methodology Applied

Scientific EffectRefraction: Refraction

Implementation Method 4

capable of sensing polarization

Methodology Applied

Scientific EffectPolarization: Polarisation

Implementation Method 5

a photoelectric conversion region provided in the substrate

Methodology Applied

Scientific EffectPhotoelectric effect: Photoelectric Effect

Data Source

PatentUS11398513B2Image sensor

Publication Date: 2022.07.26 SAMSUNG ELECTRONICS CO LTD

AI summary

An image sensor includes a substrate having a first surface and a second surface opposite to each other, a photoelectric conversion region provided in the substrate, and a polarizer provided at the first surface of the substrate. The polarizer includes a lower structure comprising at least one trench recessed from the first surface of the substrate toward the photoelectric conversion region, and a plurality of upper patterns provided on the lower structure and spaced apart from each other in a first direction parallel to the first surface.