MicroLED Optical Interconnect Layout for Dense 3D IC Routing
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Solution Overview
Problem
Existing IC packaging and interconnect technologies, such as PCBs and silicon interposers, limit IC and interconnect density, impose significant power constraints, and restrict connections to nearest-neighbor ICs due to ohmic losses and planar substrate limitations.
Innovation Solution
Implementing an optically-interconnected IC architecture using microLEDs and optical waveguides, which allow for higher IC and interconnect densities, reduced power consumption, and three-dimensional connectivity through the use of microLEDs, photodetectors, input and output waveguides, and various coupling techniques.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If PCB traces are used for IC interconnection, then manufacturing is simple, but IC and interconnect density is limited
Solution Approach 1:
The patent replaces electrical interconnection (PCB traces, wire bonds) with optical interconnection using microLEDs and optical waveguides. This substitution enables higher interconnect density by eliminating the physical constraints of electrical traces while maintaining manufacturability through integrated optical components.
Solution Approach 2:
The patent transitions from planar 2D PCB traces to three-dimensional optical waveguide structures. This dimensional change allows vertical stacking and spatial routing of connections, dramatically increasing interconnect density without proportionally increasing footprint area.
2Quantity of substance
If silicon interposers with thin electrical lines are used, then IC density increases, but power consumption increases and heat dissipation becomes difficult
Solution Approach 1:
The patent replaces electrical signal transmission through thin metal lines with optical signal transmission through waveguides. Optical transmission has lower resistive heating and lower power consumption, enabling high-density IC interconnection without the power dissipation problems of electrical interposers.
Solution Approach 2:
The patent changes the fundamental transmission medium parameter from electrical signals to optical signals. This parameter change fundamentally alters the power consumption characteristics, reducing ohmic losses and enabling higher IC densities without proportional power consumption increases.
3Device complexity
If electrical interconnects are used, then nearest-neighbor connections are simple, but connections to non-nearest-neighbor ICs require complex routing and suffer from ohmic losses
Solution Approach 1:
The patent replaces electrical interconnection with optical interconnection, eliminating ohmic losses entirely. Optical waveguides can route signals between any ICs in the array regardless of distance, with only minimal attenuation, enabling non-nearest-neighbor connections without the energy losses that plague electrical routing.
Solution Approach 2:
The patent segments the interconnect system into discrete optical components (microLEDs, waveguides, photodetectors) that can be independently positioned and routed. This segmentation allows flexible routing to any IC without the constraints of continuous electrical trace routing, reducing overall system complexity despite enabling longer-range connections.
4Ease of manufacture
If planar substrate interconnection is used, then manufacturing is straightforward, but three-dimensional connectivity and fan-out/fan-in capabilities are limited
Solution Approach 1:
The patent embeds optical waveguides within three-dimensional spaces, enabling vertical stacking and multi-level routing. This 3D connectivity allows fan-out and fan-in configurations where a single IC can connect to multiple other ICs in different planes, achieving topological flexibility while maintaining manufacturability through integrated fabrication processes.
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
Enables higher IC and interconnect densities, reduced power consumption, and complex connection topologies by utilizing microLEDs and optical waveguides, overcoming limitations of traditional electrical connections.
Implementation Method 1
a first plurality of microLEDs, each of the plurality of microLEDs being associated with and configured to be driven with signals from a corresponding one of the first plurality of ICs
Implementation Method 2
a second plurality of photodetectors, each set of the plurality of photodetectors being associated with and configured for provision of signals to a corresponding one of the second plurality of ICs
Implementation Method 3
a plurality of sets of input waveguides, each set of the input waveguides being associated with and positioned to receive optical signals from microLEDs of corresponding ones of the first plurality of ICs and to provide optical signals to different fan-in regions
Data Source
AI summary
Optical interconnect topologies may be provided using microLEDs. The topologies may interconnect ICs. The optical interconnect topologies may be used in some instances in place of electrical busses.