BEOL Cladding Structure for Photonics Light Confinement
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Solution Overview
Problem
There is a need for increased bandwidth in fiber optic network links to handle the exponential growth in data transmissions, requiring improvements in system performance and infrastructure capable of handling the increased volume of data.
Innovation Solution
The development of a cladding structure in the back end of line (BEOL) of monolithic photonics chips, integrating optical and electronic components on a unified platform, which includes a first cladding structure covering optical components and a second cladding structure extending across multiple connection levels to provide electrical isolation and light confinement, using materials with refractive indices matching those of the dielectric materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If optical components are integrated on a silicon photonics platform to increase bandwidth, then data transmission capacity is improved, but light confinement and electrical isolation become problematic due to material compatibility requirements
Solution Approach 1:
The patent changes the refractive index parameter of the cladding material to match that of the interlayer dielectric material, enabling both optical and electrical functionality. By selecting a cladding material with refractive index approximately 3.4 (matching silicon-based dielectrics), the invention achieves effective light confinement at the waveguide-cladding interface while maintaining electrical isolation properties throughout the BEOL structure.
Solution Approach 2:
The cladding structure serves multiple functions simultaneously: it provides optical confinement for light propagation in waveguides, electrical isolation between different conductive layers, and structural support for the photonics circuit. This multi-functionality is achieved by integrating the cladding into the BEOL process flow, where it becomes part of the interlayer dielectric stack while maintaining optical waveguide properties.
2Productivity
If multiple connection levels are integrated to handle increased data volume, then bandwidth is improved, but electrical isolation between levels becomes more complex
Solution Approach 1:
The patent merges the electrical isolation function with the optical cladding function by using the same material layer for both purposes. The cladding material is deposited as part of the interlayer dielectric stack in the BEOL process, simultaneously providing electrical isolation between conductive layers and optical confinement for waveguides, thereby simplifying the overall device structure.
Solution Approach 2:
The cladding material is made homogeneous with the surrounding interlayer dielectric materials by matching refractive indices and using compatible materials throughout the BEOL structure. This homogeneity allows light to propagate through waveguides without scattering at material interfaces while maintaining uniform electrical isolation properties across all connection levels.
3Ease of manufacture
If conventional separate cladding and interlayer dielectric structures are used, then manufacturing is simpler, but optical loss increases due to refractive index mismatches
Solution Approach 1:
The patent changes the refractive index parameter of the cladding material to match that of the interlayer dielectric material, eliminating scattering losses at interfaces. By selecting a cladding material with refractive index approximately 3.4 (matching silicon-based dielectrics), the invention achieves effective light confinement while minimizing optical loss throughout the waveguide structure.
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 solution enhances light confinement within waveguides and prevents loss, while providing electrical isolation and facilitating efficient signal routing, thereby improving the performance and bandwidth of photonics chips.
Implementation Method 1
a first cladding structure covering the optical component and a second cladding structure extending from the first cladding structure across a portion of the connection levels... enhancing light confinement within waveguides
Implementation Method 2
a second cladding structure extending from the first cladding structure across a portion of the connection levels... providing electrical isolation
Data Source
Figure 1~2
Figure 3
Figure 4~5
AI summary
An integrated circuit chip comprising: a substrate; an optical component above the substrate; a first connection level above the substrate, the first connection level includes the optical component and a first cladding structure, wherein the optical component is covered by the first cladding structure; a second connection level on the first connection level; and a second cladding structure directly above the optical component, the second cladding structure having at least a section within the second connection level, the second cladding structure is on the first cladding structure.