Multi-Chip Device Optical Signal Transmission
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Solution Overview
Problem
Existing multi-chip devices face signal delays and increased manufacturing costs due to wire bonding limitations and parasitic capacitance, which restrict the number of chips that can be bonded together effectively.
Innovation Solution
A multi-chip device and manufacturing method utilizing LED sensors and LEDs for signal transmission through light, with a driving circuit and insulating film, and trenches in the film to expose LEDs, allowing for efficient light-based signal transfer between chips.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If wire bonding is used to connect chips, then electrical connections are established, but signal delays increase and the number of bondable chips is limited
Solution Approach 1:
The patent replaces the mechanical wire bonding system with an optical system using LEDs and photodetectors. Light signals transmit data between chips through optical paths, eliminating the need for physical wire connections and reducing signal delay associated with long wire lengths.
Solution Approach 2:
The patent introduces optical intermediaries (LEDs and photodetectors) to facilitate communication between chips. These components convert electrical signals to optical signals and back, enabling faster transmission compared to direct electrical wire connections.
2Adaptability or versatility
If the number of chips bonded together is increased, then more functionality is achieved, but wire bonding limitations and parasitic capacitance increase
Solution Approach 1:
The patent replaces the complex wire bonding process with a simpler optical connection system. LEDs and photodetectors can be directly integrated into chip structures, eliminating the need for post-fabrication wire bonding operations and reducing manufacturing complexity.
Solution Approach 2:
The optical communication components (LEDs and photodetectors) serve multiple functions: they enable inter-chip communication, can be integrated into standard semiconductor fabrication processes, and provide a scalable solution for increasing the number of chips without proportionally increasing manufacturing complexity.
3Loss of time
If through-hole electrodes are formed to reduce signal delay, then connection paths are shortened, but manufacturing complexity increases
Solution Approach 1:
The patent replaces the need for through-hole electrodes by using optical signals that can transmit through the substrate or along the surface without requiring physical penetration holes. This maintains short effective signal paths while avoiding the complex through-hole formation and metal coating processes.
4Reliability
If repeaters are inserted to reduce line delay, then signal transmission is improved, but leakage current and power consumption increase
Solution Approach 1:
The patent replaces electrical signal repeaters with optical signal transmission. Optical signals can travel longer distances without degradation and do not require active repeater components that consume power, thereby reducing overall device power consumption while maintaining signal quality.
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 approach reduces design and manufacturing costs while minimizing signal delays by enabling efficient light-based communication between chips, overcoming the limitations of traditional wire bonding and parasitic capacitance issues.
Implementation Method 1
LEDs for emitting light formed over the wafer respectively corresponding to the LED sensors
Implementation Method 2
LED sensors for sensing light formed separated by a predetermined interval in a wafer
Data Source
AI summary
A multi-chip device includes LED sensors for sensing light separated by a predetermined interval in a wafer, LEDs for emitting light formed over the wafer respectively corresponding to the LED sensors, a driving circuit formed between the LEDs over the wafer, an insulating film over the wafer, and trenches in the insulating film exposing the LEDs.