Light Sensor Polarizer Integrated with Metal Layers
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Solution Overview
Problem
The addition of polarizers in light sensors increases manufacturing complexity and cost due to additional steps required, and crosstalk between photodiodes can occur due to unconfined incident light.
Innovation Solution
Forming polarizer components in the same layers as metal conductors and using peripheral rings to confine incident light, reducing manufacturing complexity and improving light sensor performance by aligning polarizers at different angles in a light sensor array.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If polarizers are added to light sensors to sense polarized light, then the light sensing capability is improved, but the manufacturing complexity and cost increase
Solution Approach 1:
The patent combines the polarizer structure with the metal conductor layers by forming the polarizer components (first and second metal grids) within the same metal layers as the conductors. This integration allows the polarizer to be manufactured simultaneously with the conductor layers using the same deposition and patterning processes, eliminating separate manufacturing steps and reducing overall device complexity while maintaining polarized light sensing capability
Solution Approach 2:
The metal layers in the light sensor serve dual functions: they act as both conductors for electrical connections and as polarizer components for optical filtering. The first and second metal grids formed in the metal layers provide polarizing functionality while the same layers provide electrical conductivity, allowing one structure to fulfill multiple roles and reduce manufacturing steps
2Reliability
If polarizers are added to light sensors to sense polarized light, then the light sensing capability is improved, but the manufacturing cost increases
Solution Approach 1:
The polarizer components are merged with the metal conductor layers, allowing both structures to be formed in the same manufacturing steps. The first and second metal grids are deposited and patterned together with the conductor traces using standard semiconductor fabrication processes, eliminating the need for separate polarizer manufacturing steps and reducing overall production cost
Solution Approach 2:
The metal layers serve themselves by providing both electrical conductivity and optical polarizing functions. The same metal material and structure that provides electrical connections also provides the polarizing effect, eliminating the need for additional specialized materials or components and reducing manufacturing cost
3Reliability
If peripheral rings are added to confine incident light, then crosstalk between photodiodes is reduced, but the device complexity increases
Solution Approach 1:
The peripheral rings are integrated with the existing polarizer structure by forming them as extensions of the first and second metal grids. The rings are created using the same deposition and patterning processes as the polarizer grids, allowing the light confinement structure to be manufactured simultaneously with the polarizer without adding separate fabrication steps or significant device complexity
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 reduces the cost and complexity of manufacturing light sensors with polarizers while enhancing their performance by minimizing crosstalk and optimizing light confinement.
Implementation Method 1
a microlens focusing incident light onto the photodiode
Implementation Method 2
The polarizer is disposed above and aligned with the photodiode such that the polarizer polarizes incident light traveling from the microlens to the photodiode
Implementation Method 3
The photodiode generates charge in response to incident light directed through the front side of the light sensor
Data Source
AI summary
A light sensor includes a photodiode, interlayer dielectric layer and plurality of metal layers. A polarizer is disposed in the plurality of metal layers. The photodiode is coupled to generate charge in response to incident light directed through a first side of the semiconductor layer. The polarizer includes a first metal grid formed with a first metal layer and a second metal grid formed with a third metal layer. The second metal grid is stacked with the first metal grid such that the first and second metal grids are disposed above and aligned with the photodiode. The photodiode is optically coupled to receive incident light through the first and second metal grids of the polarizer and through the first side of the semiconductor layer.