Hybrid Integrated Module Optical Signal Loss Reduction
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Solution Overview
Problem
Silicon-on-insulator (SOI) technology faces challenges in integrating optical components and electronic circuits due to differences in design parameters, leading to significant evanescent coupling of optical signals to the silicon substrate, resulting in increased optical losses.
Innovation Solution
A hybrid integrated module is developed, where a semiconductor die is mechanically coupled to an integrated device with a removed substrate, featuring an optical device on the back surface of a thin oxide layer, allowing for evanescent coupling of optical signals between the optical waveguide and the optical device, and enabling the use of materials like III-V semiconductors with electronic circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the BOX layer thickness is reduced to accommodate electronic circuit design parameters, then electronic circuits can be integrated with optical components, but optical losses increase due to evanescent coupling to the silicon substrate
Solution Approach 1:
The patent removes the silicon substrate entirely from the integrated device, extracting the source of optical absorption and scattering losses. This allows the optical waveguide to operate without evanescent coupling to a lossy substrate while still enabling electronic circuit integration through the semiconductor die bonded to the thinned SOI structure.
Solution Approach 2:
The patent thins the SOI structure to a few micrometers and bonds it face-to-face with a semiconductor die, creating a three-dimensional integrated module architecture. This dimensional reorganization allows optical components to operate in a low-loss environment while electronic circuits are integrated in a separate but mechanically coupled substrate.
2Loss of energy
If the BOX layer thickness is increased to confine optical signals, then optical losses are reduced, but design freedom for integrating different materials and structures is constrained
Solution Approach 1:
The patent segments the integrated module into two independent parts: an optical device fabricated on thinned SOI and a semiconductor die containing electronic circuits. This segmentation allows each component to be optimized independently - the optical waveguide can use a thin BOX layer for design flexibility while the semiconductor die provides electronic functionality, with both bonded together through adhesive and solder balls.
3Reliability
If a thick BOX layer is used to prevent optical coupling to the substrate, then optical signal confinement is improved, but the ability to integrate optical devices on the back surface is limited
Solution Approach 1:
The patent inverts the conventional approach by removing the substrate entirely and bonding the thinned SOI structure face-to-face with a semiconductor die. This inversion allows optical devices to be integrated on the back surface of the oxide layer, as the semiconductor die serves as the mechanical support rather than a lossy silicon substrate.
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
This configuration reduces optical losses, provides additional design freedom, and allows for power-efficient operation with lower power consumption, facilitating the integration of photonic and electronic circuits without imposing constraints on thickness, thus optimizing both optical and electrical functions independently.
Implementation Method 1
the thickness of the semiconductor layer and the thickness of the oxide layer are defined so that an optical signal is evanescently coupled between the optical waveguide and the optical device
Data Source
Figure 1
Figure 2A~2B
Figure 3
AI summary
A hybrid integrated module (100) includes a semiconductor die (110) mechanically coupled face-to-face to an integrated device (116) in which substrate has been removed. For example, the integrated circuit includes an optical waveguide (136) that conveys an optical signal, which is fabricated on a silicon-on-insulator (SOI) wafer in which the back-side silicon substrate or handler has been completely removed. An optical device (134) is disposed on the bottom surface (130) of an oxide layer (126) (such as a buried-oxide layer) in the integrated device, and the geometry and materials in the integrated device (116) are selected and/or defined so that the optical signal is evanescently coupled between the optical waveguide (136) and the optical device (134).