Backside Micro-LED Assembly for Low-Loss Die-to-Die Optical Links
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Copper traces experience significant loss for high-frequency signals in communication between dies on the same circuit board, limiting bandwidth efficiency.
Innovation Solution
Implementing a micro-LED assembly mounted on the back side of a semiconductor die connected via through-silicon vias to circuitry on the front side, with optical cables for signal transmission, allowing high-frequency signals to be converted to optical signals with low loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If copper traces are used to carry high-frequency signals between dies, then electrical connection is achieved, but signal loss increases significantly
Solution Approach 1:
The patent replaces the electrical conduction mechanism (copper traces) with an optical transmission mechanism (micro-LED assembly). High-frequency electrical signals are converted to optical signals that travel through optical cables, eliminating the resistive losses and electromagnetic interference inherent in copper trace transmission. This substitution enables low-loss signal transmission while maintaining high bandwidth efficiency.
Solution Approach 2:
The micro-LED assembly mounted on the back side of the die serves as an intermediary device. It receives electrical signals from through-silicon vias, converts them to optical signals, and transmits them via optical cables. This intermediary conversion process resolves the contradiction by transforming the signal carrier from electrical (lossy at high frequencies) to optical (low loss), thereby improving both signal loss characteristics and bandwidth efficiency.
2Loss of energy
If copper traces are used for short-distance communication between dies, then electrical connection is established, but signal loss becomes significant even for adjacent dies
Solution Approach 1:
The patent substitutes electrical signal transmission through copper traces with optical signal transmission through optical cables. This substitution enables signal transmission over much longer distances (up to 1,000 meters as stated in the patent) while maintaining low signal loss, overcoming the distance limitation of copper trace-based electrical communication.
3Loss of energy
If micro-LED assembly is mounted on back side of die, then optical signal transmission is enabled, but device complexity increases
Solution Approach 1:
The patent moves the micro-LED assembly from the front side to the back side of the die, utilizing the third dimension (vertical stacking) to resolve the contradiction. This spatial reconfiguration allows optical transmission capabilities to be added without interfering with the front-side circuitry, thereby enabling low-loss optical communication while managing device complexity through three-dimensional integration rather than planar expansion.
Solution Approach 2:
The patent segments the communication function into separate modules: through-silicon vias for electrical connection, micro-LED assembly for signal conversion, and optical cables for transmission. This segmentation allows each component to be optimized independently and facilitates modular integration, reducing overall system complexity despite adding optical capabilities.
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 high-bandwidth signal transmission with low loss between IC dies, supporting distances up to 1,000 meters with frequencies up to 32 gigahertz.
Implementation Method 1
a micro-light-emitting diode (micro-LED) assembly comprising one or more micro-LEDs
Implementation Method 2
micro-LED assembly mounted on the back side of the integrated circuit die... allowing high-frequency signals to be converted to optical signals
Data Source
AI summary
Technologies for back side micro-LED assemblies are disclosed. In an illustrative embodiment, a micro-LED assembly includes several micro-LEDs and several photodiodes mounted on a base die. The base die is mounted on an integrated circuit (IC) die, such as a processor die. Through-silicon vias are defined in the IC die to carry electrical signals between the micro-LED assembly and transistors and other components near or at the front side of the IC die. An optical plug with an optical cable is positioned above the micro-LED assembly to couple light to and from the micro-LEDs and photodiodes. The short distance between the transistors on the front side of the IC die and the micro-LED assembly allows for high-bandwidth signals to be converted to optical signals with little loss. The optical cable can connect IC dies on the same circuit board, in the same housing, in the same rack, etc.