MicroLED Optical Interconnects for Low-Power Chip-to-Chip Links
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Solution Overview
Problem
Current electrical interconnects at short distances face limitations due to RC time constants, power consumption, and 2D confinement, which hinder high-speed computation and memory access in integrated circuits.
Innovation Solution
The use of microLEDs for inter-chip optical communication, coupled with waveguides, enables fast, low-power, and low-cost data connections between semiconductor chips, breaking the barriers of traditional electrical interconnects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If electrical interconnects are used for short-distance connections, then the connection is simple and established, but power consumption increases and signal loss occurs due to RC time constants
Solution Approach 1:
The patent replaces electrical interconnects with optical interconnects using microLEDs as light sources and photodetectors as receivers. This substitution eliminates the RC time constant limitations and parasitic effects inherent in electrical connections, achieving lower power consumption and better signal integrity for short-distance communications within and between chips.
Solution Approach 2:
The patent introduces optical waves as an intermediary medium for data transmission. Instead of direct electrical signal transmission through metal interconnects, electrical signals are converted to optical signals via microLEDs, transmitted through optical waveguides or free space, and converted back to electrical signals via photodetectors, thereby avoiding the limitations of electrical interconnects.
2Productivity
If electrical interconnects are used on chip surface, then the connection is straightforward, but the interconnects are confined to 2D plane limiting bandwidth
Solution Approach 1:
The patent transitions from 2D planar electrical interconnects to 3D optical interconnects. Optical signals can propagate in three-dimensional space including through vertical waveguides, enabling stacked chip architectures and significantly increasing bandwidth without proportionally increasing interconnect complexity.
3Speed
If optical components are deployed for high-speed links, then bandwidth increases, but cost increases due to manufacturing infrastructure requirements
Solution Approach 1:
The patent changes the scale parameter of LEDs from conventional sizes to micro-scale dimensions. This miniaturization enables higher integration densities and allows the use of standard semiconductor manufacturing processes, thereby reducing the cost of optical interconnect deployment while maintaining high data transfer rates.
4Loss of time
If more cache is integrated into the chip, then memory access speed increases, but chip area increases
Solution Approach 1:
The patent enables vertical stacking of memory chips using 3D optical interconnects through waveguides. This allows cache and memory to be positioned in three-dimensional space above the processor chip, increasing memory capacity and reducing access latency without increasing the footprint of the processor chip itself.
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 solution allows for synchronized clock signals, efficient data transfer across chips, and connectivity to memory and peripherals, thereby overcoming the limitations of electrical interconnects and enhancing high-speed computation.
Implementation Method 1
a first microLED coupled to the first semiconductor chip within the semiconductor package; circuitry within the semiconductor package for driving the first microLED based on signals of the logic circuitry of the first semiconductor chip
Implementation Method 2
at least one waveguide; and a first photodetector within the semiconductor package optically coupled to the first microLED by the at least one waveguide
Implementation Method 3
a first photodetector within the semiconductor package optically coupled to the first microLED by the at least one waveguide, the first photodetector electrically coupled to the logic circuitry of the second semiconductor chip
Data Source
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AI summary
In package intra-chip and/or inter-chip optical communications are provided using microLEDs and photodetectors mounted to integrated circuit (IC) chips and/or to transceiver dies associated with the IC chips. Light from the LEDs may pass through waveguides on or in a substrate to which the IC chips are mounted or which couple the IC chips.