Optical IC Package Layout for Interference-Free Light Paths
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Solution Overview
Problem
Ensuring an adequate and distortion-free light path for photonic integrated circuits (ICs) within integrated packages that include both electronic and photonic ICs, while minimizing interference from dielectric layers and interfaces.
Innovation Solution
Employing hybrid bonding techniques to securely integrate photonic and electronic ICs, forming optical features like grating couplers, and removing interconnect structure portions to create an unobstructed optical path filled with optically compatible dielectric materials to reduce optical interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If dielectric layers and interconnect structures are used to integrate photonic and electronic ICs, then device integration and functionality are improved, but optical interference (reflection and refraction) increases
Solution Approach 1:
The patent removes portions of the interconnect structure to create openings in the optical path. This extraction eliminates the harmful optical interference from metal interconnect layers while preserving the electrical connectivity functions through alternative routing. The openings are strategically positioned to allow light signals to pass through the package substrate without encountering reflective or refractive interfaces.
Solution Approach 2:
The patent introduces a gap fill material as an intermediary substance to fill the openings created in the interconnect structure. This gap fill material serves as an optical mediator with matched refractive index that reduces optical interference at interfaces while maintaining the structural integrity of the package. The material acts as a transition medium between the air above and the dielectric layers below, minimizing reflection and refraction.
2Reliability
If grating couplers are added to the photonic IC, then optical coupling capability is improved, but device complexity increases
Solution Approach 1:
The patent combines the grating coupler structure with the existing interconnect structure layers. The optical coupling features are integrated into the same packaging structure that provides electrical connectivity, merging optical and electrical functions into a unified design. This approach reduces overall device complexity by eliminating separate optical coupling components and utilizing the existing layered architecture for both optical and electrical purposes.
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
Achieves a robust and interference-free optical path for light signal transmission, enhancing the performance and efficiency of integrated photonic ICs by minimizing reflection and refraction within the package.
Implementation Method 1
the gap fill material having a refractive index matched to that of the optical feature and imposing a second degree of optical interference on the light path that is less than the first degree of optical interference
Data Source
AI summary
A packaged device includes an optical IC having an optical feature therein. An interconnect structure including layers of conductive features embedded within respective layers of dielectric materials overlie the optical feature. The interconnect structure is patterned to remove the interconnect structure from over the optical feature and a dielectric material having optically neutral properties, relative to a desired light wavelength(s) is formed over the optical feature. One or more electronic ICs may be bonded to the optical IC to form an integrated package.