Image Sensor Absorption Structure for Color-IR Cross-Talk
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Solution Overview
Problem
Complementary metal-oxide semiconductor (CMOS) image sensors experience cross-talk between laterally adjacent image sensor elements configured for different wavelengths, leading to a decreased signal-to-noise ratio (SNR) and performance degradation.
Innovation Solution
Incorporating an absorption structure with a conductive material like titanium nitride or tungsten underlying the first image sensor element to prevent reflection of electromagnetic radiation within specific wavelengths, thereby reducing cross-talk between neighboring image sensor elements and increasing the SNR of adjacent elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If image sensor elements are arranged laterally adjacent to each other for different wavelengths, then device integration and compactness are improved, but cross-talk between elements increases and signal-to-noise ratio deteriorates
Solution Approach 1:
An absorption layer is introduced as an intermediary structure between laterally adjacent image sensor elements. This layer absorbs electromagnetic radiation that would otherwise reflect off conductive interconnect structures and cause cross-talk in neighboring elements, thereby maintaining high device integration while improving signal-to-noise ratio.
Solution Approach 2:
The harmful reflected electromagnetic radiation is extracted or removed from the system by the absorption layer, which captures and dissipates the energy before it can reach adjacent sensor elements, thus eliminating the cross-talk problem while preserving compact integration.
2Reliability
If absorption structures with conductive materials are added to reduce cross-talk, then signal-to-noise ratio is improved, but device complexity and manufacturing steps increase
Solution Approach 1:
The absorption layer is merged with existing conductive interconnect structures in the image sensor device. By integrating the absorption function into the conductive layer that is already part of the device architecture, the solution reduces cross-talk without adding separate, independent structures, thereby limiting the increase in device complexity.
Solution Approach 2:
The conductive interconnect structures serve dual functions: electrical connection and electromagnetic radiation absorption. This multi-functionality allows the same structure to perform both its original electrical role and the new radiation absorption role, reducing the need for additional dedicated absorption structures and simplifying the overall device design.
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
The absorption structure effectively decreases cross-talk between image sensor elements, enhancing the signal-to-noise ratio and overall performance of the image sensor device by impeding electromagnetic radiation from reflecting to adjacent sensors, thus improving image reliability and accuracy.
Implementation Method 1
an absorption structure with a conductive material like titanium nitride or tungsten underlying the first image sensor element to prevent reflection of electromagnetic radiation within specific wavelengths
Data Source
AI summary
Various embodiments of the present disclosure are directed towards an image sensor device including a first image sensor element and a second image sensor element disposed within a substrate. An interconnect structure is disposed along a front-side surface of the substrate and comprises a plurality of conductive wires, a plurality of conductive vias, and a first absorption structure. The first image sensor element is configured to generate electrical signals from electromagnetic radiation within a first range of wavelengths. The second image sensor element is configured to generate electrical signals from the electromagnetic radiation within a second range of wavelengths that is different than the first range of wavelengths. The second image sensor element is laterally adjacent to the first image sensor element. Further, the first image sensor element overlies the first absorption structure and is spaced laterally between opposing sidewalls of the first absorption structure.