Optical Sensor Light-Guiding Structure for Reduced Scattering
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Solution Overview
Problem
Optical sensors face challenges in efficiently directing light from sample-holding portions to light-sensing regions while minimizing size and preventing light scattering, which affects their performance and quantum efficiency.
Innovation Solution
A light-guiding structure with a ring-shaped design and tilted sidewalls is integrated into the optical sensor, using dielectric layers and shared fabrication processes with electrical interconnects and photodiodes to enhance light directionality and reduce size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional light-guiding structures are used, then light directionality is achieved, but light scattering occurs and device size is large
Solution Approach 1:
The patent employs a curved light-guiding structure with a specific arc-shaped geometry. The curved surface is designed with a radius of curvature that optimizes light reflection angles, directing emitted light efficiently toward the sensing region while minimizing scattering. This curvature-based design replaces traditional flat or angular light guides, achieving superior light control.
2Reliability
If traditional optical sensor designs are used, then light sensing function is achieved, but device size is large
Solution Approach 1:
The patent integrates multiple functions into a single unified structure. The light-guiding structure serves dual purposes: it guides light from the sample chamber to the sensing region while also acting as a structural support element and optical isolation barrier. This merging of functions eliminates the need for separate components, significantly reducing device volume.
Solution Approach 2:
The patent transitions from a planar two-dimensional layout to a three-dimensional vertical integration architecture. The light-guiding structure extends in the vertical dimension, utilizing the Z-axis to route light paths efficiently. This dimensional change allows compact packaging of optical components without compromising light sensing performance.
3Ease of manufacture
If separate fabrication processes are used for optical and electrical components, then manufacturing flexibility is maintained, but manufacturing complexity increases
Solution Approach 1:
The patent designs the light-guiding structure using standard semiconductor fabrication-compatible materials and processes. The same deposition, etching, and planarization techniques used for electrical interconnects are also employed to create the optical guiding features. This universal approach allows a single fabrication line to produce both optical and electrical components, simplifying manufacturing while maintaining flexibility.
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 light-guiding structure effectively prevents light scattering, improves light directionality to the sensing region, and allows for a significant reduction in the optical sensor's size through integrated fabrication with electrical components.
Implementation Method 1
A light-guiding structure with a ring-shaped design and tilted sidewalls is integrated into the optical sensor... to enhance light directionality
Implementation Method 2
The light-guiding structure effectively prevents light scattering, improves light directionality to the sensing region
Data Source
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Figure 1C
AI summary
An optical sensor (100) including a semiconductive layer (111), such as a silicon substrate, having an electrical circuit area (111A) and an optical sensing area (111B), preferably comprising a light sensing region (55), such as a multi-junction photodiode, a sample-holding portion (23) over the optical sensing area (111B), a light-guiding structure (130) between the sample-holding portion (23) and the optical sensing area (111B), and an electrical interconnect structure (140), preferably comprising electrical contacts (141) and/or electrical vias (142) and/or electrical layers (143), over the electrical circuit area (111A). The electrical interconnect structure (140) is integrally formed with the light-guiding structure (130), and the light-guiding structure (130) is configured to direct an emitting light (81) from the sample-holding portion (23) to the optical sensing area (111B). The light-guiding structure is designed to prevent light scattering and to direct the emitting light (81) from the sample-holding portion (23) more efficiently the light-sensing region (55) in the optical sensing area (111B). Furthermore, the fabrication of the light-guiding structure (130) complies with the back-end-of-line (BEOL) metallization technology and can be fabricated by the same fabrication process in the same die as the electrical interconnected structure (140) and the multi-junction photodiode of the light-sensing region (55). In addition, the size of the optical sensor can be decreased.