Optical Shielding Vias for Stray Light Isolation in Integrated Circuits
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Solution Overview
Problem
Existing integrated circuits face challenges in effectively shielding light-sensitive components from stray light, which can degrade performance and increase circuit size and losses.
Innovation Solution
Implementing optically shielding vias (OSVs) with engineered patterns and materials to absorb or redirect undesirable light, optimized for optical wavelengths, combined with redistribution layers and anti-reflective coatings to enhance optical isolation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If traditional vias are used for electrical connection, then electrical connectivity is achieved, but optical shielding is insufficient allowing stray light to reach sensitive components
Solution Approach 1:
The patent introduces light-impeding structures as intermediary elements between the optical waveguide and photodetector. These structures act as mediators that selectively block stray light paths while allowing the desired optical signal to reach the photodetector through the waveguide, thus resolving the contradiction between electrical connectivity and optical shielding.
Solution Approach 2:
The patent applies local quality by making the vias have different properties in different regions: the first via has a light-impeding structure (such as a reflective coating or absorptive material) specifically at its lower portion near the photodetector, while the upper portion remains transparent to allow optical signal transmission. This localized modification provides targeted optical shielding without compromising overall signal transmission.
2Object-affected harmful factors
If light-impeding structures are added to block stray light, then optical shielding is improved, but device complexity increases
Solution Approach 1:
The patent segments the via structure into distinct functional portions: an upper portion for electrical connection and optical signal transmission, and a lower portion with light-impeding structures for optical shielding. This segmentation allows each portion to be optimized independently, reducing overall device complexity while achieving the desired optical shielding effect.
Solution Approach 2:
The patent makes the via structure multi-functional by combining electrical connectivity, optical signal transmission, and optical shielding functions within a single via element. The first via simultaneously serves as an electrical interconnection, allows optical signals to pass through its upper portion, and blocks stray light through its lower portion's light-impeding structure, thereby reducing the need for separate shielding components.
3Object-affected harmful factors
If via separation distance is increased to reduce light interference, then optical isolation is improved, but integrated circuit density decreases
Solution Approach 1:
The light-impeding structures within the vias act as intermediary shielding elements that enable close spacing of vias while maintaining optical isolation. By incorporating these structures directly within the via elements rather than requiring increased separation distances, the patent achieves optical crosstalk reduction without sacrificing chip area utilization.
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
Reduces stray light impinging on sensitive components, improving signal detection sensitivity and reducing circuit size and losses, while enabling integration of chips with enhanced signal-to-noise ratio and lower power consumption.
Implementation Method 1
a plurality of light-impeding structures configured to absorb light, reflect light, or both absorb and reflect light
Implementation Method 2
a plurality of light-impeding structures configured to absorb light, reflect light, or both absorb and reflect light
Data Source
AI summary
Positioned between first and second planes of a volume are one or more optical elements. Light-impeding structures absorb light, reflect light, or both. Each light-impeding structure in a first set: intersects the first (and second) plane with a first (and second) cross-sectional shape, comprises a first (and second) maximum cross-sectional length equal to the length of the longest line between two maximally separated points of the first (and second) cross-sectional shape, and is separated from nearest neighboring light-impeding structures in the first set by a distance no larger than four times the length of the first maximum cross-sectional length or four times the length of the second maximum cross-sectional length. Light propagation through one or more points is impeded, such that any line that intersects at least one of the points, is entirely within the volume, and traverses through the first set, intersects at least one light-impeding structure.