Monolithic IR-Visible Image Sensor Stacking for High Resolution
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Solution Overview
Problem
Current image sensors that integrate infrared and visible light sensors often suffer from reduced resolution and complex manufacturing processes due to separate fabrication and bonding of infrared and visible light sensor portions, leading to inefficiencies in image generation and alignment.
Innovation Solution
The integration of infrared and visible light sensors into a single, substrate-based monolithic structure, where both sensors share a common semiconductor substrate without the need for bonding pads or through-holes, allowing for improved alignment and higher resolution imaging by forming the sensors through continuous semiconductor processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If infrared and visible light sensors are integrated using separate fabrication and bonding processes, then both sensor types can be combined in one device, but manufacturing complexity increases and alignment precision deteriorates
Solution Approach 1:
The patent merges the infrared sensor and visible light sensor into a single monolithic structure fabricated on one semiconductor substrate using continuous semiconductor processes. This eliminates the need for separate fabrication and bonding operations, thereby reducing manufacturing complexity while maintaining sensor integration. The merged structure allows both sensor types to coexist on the same substrate without requiring complex alignment procedures.
Solution Approach 2:
The patent arranges the infrared sensor and visible light sensor in a stacked configuration along the vertical dimension of the semiconductor substrate. This spatial arrangement in another dimension (vertical stacking rather than lateral placement) enables both sensors to be integrated without increasing lateral device footprint and simplifies the manufacturing process by allowing sequential formation of sensor layers through standard semiconductor fabrication techniques.
2Adaptability or versatility
If separate fabrication and bonding processes are used for integrating sensors, then both sensor types can be combined, but manufacturing precision and alignment accuracy deteriorate
Solution Approach 1:
By merging the fabrication processes for infrared and visible light sensors into a single continuous semiconductor manufacturing process on one substrate, the patent eliminates the need for separate bonding operations. This ensures that both sensor types are formed with precise alignment inherent to the semiconductor fabrication process, avoiding the alignment errors that would occur with separate bonding steps.
3Adaptability or versatility
If sensor area is divided into color pixels and infrared pixels, then both sensor functions are achieved, but image resolution of the RGB sensor deteriorates
Solution Approach 1:
The patent places the infrared sensor and visible light sensor in different vertical layers on the semiconductor substrate, with the infrared sensor in a first region and the visible light sensor in a second region stacked above or beside it. This vertical stacking in another dimension allows both sensor types to operate simultaneously without competing for the same lateral pixel area, thereby preserving the full resolution of the RGB color image sensor while adding infrared sensing capability.
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 higher-resolution image generation by eliminating the need for separate alignment structures and simplifying the manufacturing process, resulting in improved optical efficiency and precise alignment between sensor elements.
Implementation Method 1
a plurality of visible light sensing elements are arrayed in the first sensor layer... configured to convert optical images into electrical signals
Implementation Method 2
a plurality of infrared sensing elements are arrayed in the second sensor layer... configured to process a signal output from the second sensor layer
Data Source
AI summary
An image sensor includes a visible light sensor portion and an infrared sensor portion arranged on the visible light sensor portion. The visible light sensor portion includes a first sensor layer and a first signal wiring layer, wherein a plurality of visible light sensing elements are arrayed in the first sensor layer and the first signal wiring layer is configured to process a signal output from the first sensor layer. The infrared sensor portion includes a second sensor layer in which a plurality of infrared sensing elements are arrayed, and a second signal wiring layer configured to process a signal output from the second sensor layer. The infrared sensor portion and the visible light sensor portion form a single monolithic structure which is effective in obtaining high resolution.