Polarizing Grating Structures for Backside Illuminated Image Sensors
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Backside illuminated image sensor devices face challenges in integrating polarizers, leading to increased product size and restricted size reduction efforts, as well as slower polarization data acquisition due to external polarizers that need to rotate for different polarization conditions.
Innovation Solution
The integration of polarizing grating structures within the composite grid structure by replacing color filters, allowing for polarization information collection along specific angles such as 0°, 45°, 90°, and 135°, with grating elements having optimized pitch and width ranges for incident light wavelengths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If external polarizers are used for backside illuminated image sensor devices, then polarization detection capability is achieved, but product size increases and size reduction is restricted
Solution Approach 1:
The patent combines the polarizer with the existing composite grid structure by integrating polarizing grating structures into the color filter array. This merging eliminates the need for separate external polarizers, achieving polarization detection while maintaining compact device dimensions.
Solution Approach 2:
The composite grid structure is designed to serve multiple functions simultaneously: color filtering, polarization detection, and light guidance. By making the grid structure multi-functional, the patent eliminates the need for additional dedicated polarization components, thereby reducing overall device volume.
2Loss of information
If external polarizers rotate for different polarization conditions, then comprehensive polarization data is collected, but data acquisition speed decreases
Solution Approach 1:
The patent segments the polarization detection function across multiple fixed polarizing grating structures with different orientation angles within the composite grid. This segmentation allows simultaneous capture of polarization information from multiple angles in a single exposure, eliminating the need for sequential rotation and significantly improving acquisition speed.
Solution Approach 2:
The patent transitions from temporal dimension (sequential rotation over time) to spatial dimension (multiple fixed orientations arranged in space). By arranging polarizing gratings with different orientations at different spatial positions within the grid, the system captures comprehensive polarization data simultaneously across multiple angles without temporal sequencing.
3Volume of moving object
If polarizing grating structures are integrated into composite grid structure, then device compactness is improved, but manufacturing complexity increases
Solution Approach 1:
The patent optimizes specific parameters of the polarizing grating structures, including pitch ranges (100-500 nm) and width ranges (20-300 nm), to achieve effective polarization functionality while maintaining compatibility with existing manufacturing processes. These parameter optimizations enable compact integration without requiring fundamentally new manufacturing capabilities.
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 approach enables a compact design with no moving parts, allowing for simultaneous collection of polarization information across various angles, enhancing the efficiency and speed of polarization data acquisition.
Implementation Method 1
a polarizing grating in the one or more cells of the grid structure configured to polarize the light incoming to the semiconductor image sensor
Data Source
AI summary
The present disclosure is directed to a method of forming a polarization grating structure (e.g., polarizer) as part of a grid structure of a back side illuminated image sensor device. For example, the method includes forming a layer stack over a semiconductor layer with radiation-sensing regions. Further, the method includes forming grating elements of one or more polarization grating structures within a grid structure, where forming the grating elements includes (i) etching the layer stack to form the grid structure and (ii) etching the layer stack to form grating elements oriented to a polarization angle.