Optical Through-Via Waveguide Layout for 3DIC Signal Transfer
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Solution Overview
Problem
Isolating photonic components onto a single side of a substrate or interposer limits the ability to use photonics in three-dimensional integrated circuit (3DIC) structures, increasing production cost and device size due to the conversion and re-conversion of optical signals through conductive through substrate vias (TSVs).
Innovation Solution
Implementing optical through vias (OTVs) with reflective elements on opposite sides of the substrate or interposer to change the direction of optical signal propagation, using tunable reflectors controlled by conductive elements or doped regions to direct signals without the need for additional conversions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If photonic components are isolated on a single side of the substrate, then device structure is simplified, but optical signal transfer efficiency deteriorates requiring conversion to electrical signals
Solution Approach 1:
The patent transitions from planar 2D photonic component arrangement to 3D vertical arrangement by extending waveguides through the substrate thickness, enabling optical signals to propagate in the vertical dimension and directly connect components on opposite sides without electrical conversion
Solution Approach 2:
The patent introduces an optical through via (OTV) as an intermediary structure that enables direct optical coupling between waveguides on opposite sides of the substrate, replacing the need for electrical signal conversion and re-conversion while maintaining optical signal integrity
2Reliability
If optical signals are converted to electrical signals and back, then signal transfer between opposite sides is enabled, but production cost increases
Solution Approach 1:
The patent extracts and removes the electrical signal conversion components (photodetectors, lasers, electrical interconnects) from the signal path by implementing direct optical coupling through the substrate, eliminating the need for optical-to-electrical and electrical-to-optical conversion stages
Solution Approach 2:
The patent creates an optical copy pathway through the substrate using the OTV structure, allowing optical signals to be transmitted directly without being converted to electrical signals, thereby preserving signal integrity and reducing manufacturing complexity
3Reliability
If optical signals are converted to electrical signals, then signal transfer across substrate is achieved, but device size increases
Solution Approach 1:
The patent merges the optical waveguide structures from opposite sides of the substrate into a unified continuous optical pathway through the OTV, eliminating the need for separate electrical conversion components and reducing overall device volume
Solution Approach 2:
The patent utilizes the vertical dimension through the substrate to create a direct optical pathway, avoiding the need for lateral expansion that would be required for electrical conversion components, thus maintaining compact device footprint
4Reliability
If optical signals are converted to electrical signals, then signal transfer is enabled, but signal transfer accuracy deteriorates due to conversion errors
Solution Approach 1:
The patent introduces the OTV as an optical intermediary that maintains signal integrity by keeping the signal in the optical domain throughout transmission, eliminating conversion errors that would occur at optical-to-electrical and electrical-to-optical interfaces
Solution Approach 2:
The patent ensures continuous optical signal propagation through the substrate without interruption or conversion to electrical signals, maintaining uninterrupted optical signal integrity and eliminating errors introduced by discrete conversion stages
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 production costs and device size by directly transferring optical signals between layers in 3DICs, minimizing signal transfer errors and component complexity.
Implementation Method 1
The implementation of an optical through via (OTV) that uses reflective elements on opposite sides of the substrate to change the direction of optical signals within waveguides
Implementation Method 2
depositing a core material into the core opening, wherein the core material has a second refractive index different from the first refractive index, and the core material is optically transparent
Implementation Method 3
The optical signals propagate along the optical waveguide
Data Source
AI summary
A method of making a semiconductor device includes defining an opening extending from a first side of a substrate to a second side of the substrate, wherein the first side of the substrate is opposite the second side of the substrate. The method further includes depositing a dielectric material into the opening, wherein the dielectric material has a first refractive index. The method further includes etching the dielectric material to define a core opening extending from the first side of the substrate to the second side of the substrate. The method further includes depositing a core material into the core opening, wherein the core material has a second refractive index different from the first refractive index, and the core material is optically transparent. The method further includes removing excess core material from a surface of the substrate.