Optical Interconnects for Stacked Semiconductor Dies
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Solution Overview
Problem
Conventional die-stacking techniques in integrated circuits face challenges with long electrical pathways leading to high inductance and low electrical performance, as well as limitations in heat sink mounting and flexibility in chip arrangement.
Innovation Solution
Implementing optical signal transmission and reception means between semiconductor dies, utilizing optical transmitters and receivers to enable fast and reliable data transfer, thereby reducing electrical pathways and enhancing signaling speed and standardization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If bonding wires are used to establish electrical conductivity between stacked dies, then electrical connectivity is achieved, but inductance increases and electrical performance deteriorates
Solution Approach 1:
The patent replaces electrical signal transmission through bonding wires with optical signal transmission through optical fibers. Optical signals travel through dielectric material rather than conductive paths, eliminating the inductance problem inherent in electrical connections while maintaining reliable connectivity between stacked dies
Solution Approach 2:
The patent introduces optical fibers as an intermediary medium between stacked dies. These optical fibers act as a bridge that converts electrical signals to optical signals for transmission, then converts them back, providing a high-speed communication channel that avoids the inductance issues of direct electrical bonding wire connections
2Loss of information
If conventional electrical interconnects are used between stacked dies, then data transmission is achieved, but parasitic capacitances increase and signaling speed decreases
Solution Approach 1:
The patent substitutes electrical interconnects with optical interconnects. By using optical fibers and light-based transmission, the system eliminates parasitic capacitances inherent in electrical interconnect structures, enabling faster signaling speeds and reducing time delays in data transmission between stacked dies
3Reliability
If bulk semiconductor side is used for die stacking, then electrical connectivity is established, but heat sink mounting becomes unavailable
Solution Approach 1:
The patent enables the bulk semiconductor side to serve dual functions: maintaining electrical connectivity through optical interconnects while simultaneously providing a mounting surface for heat sinks. The optical fiber integration allows the rear side of the substrate to be used for both signal transmission and thermal management purposes
4Ease of operation
If long electrical pathways are used for signal transfer, then connectivity between distant points is achieved, but inductance increases and performance slows
Solution Approach 1:
The patent replaces long electrical pathways with optical fiber pathways. Optical signals can travel through dielectric material over longer distances without suffering from the inductance accumulation that plagues electrical signals, maintaining connectivity while preserving signal integrity and speed over extended path lengths
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 allows for high-speed, high-bandwidth data transmission and improved data rates in a standardized manner, reducing parasitic capacitances and enabling efficient heat management.
Implementation Method 1
A first optical transmitter and a first optical receiver are provided in the first semiconductor die, a second optical transmitter is provided in the second semiconductor die
Implementation Method 2
a first optical transmitter and a first optical receiver are provided in the first semiconductor die, a second optical transmitter is provided in the second semiconductor die, and a second optical receiver is provided in the third semiconductor die
Data Source
AI summary
A method includes forming a stack of semiconductor die. The stack includes a first semiconductor die, a second semiconductor die and a third semiconductor die. The first semiconductor die is stacked above the second semiconductor die and the third semiconductor die is stacked above the first semiconductor die. A first optical transmitter and a first optical receiver are provided in the first semiconductor die, a second optical transmitter is provided in the second semiconductor die, and a second optical receiver is provided in the third semiconductor die. A first optical signal is transmitted from the first optical transmitter in the first semiconductor die to the second optical receiver in the third semiconductor die. A second optical signal is transmitted from the second optical transmitter in the second semiconductor die to the first optical receiver in the first semiconductor die.