Thermal Substrate Contacts for SOI Chip Heat Dissipation
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Solution Overview
Problem
Integrated circuits with oxide layers between transistors and substrates face challenges in heat dissipation due to the oxide layer's poor thermal conductivity, leading to reduced operating lifetimes and increased risk of logic errors, especially when overclocked, as heat generated by transistors is poorly transferred through the substrate.
Innovation Solution
The implementation of thermal substrate contacts that pass through the oxide layer and directly contact the substrate, enhancing both downward and upward thermal conduction to increase cooling efficiency and reduce peak temperatures, thereby extending the operational lifespan of integrated circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an oxide layer is used between transistors and substrate to reduce leakage current, then electrical insulation is improved, but heat dissipation deteriorates
Solution Approach 1:
The oxide layer is segmented by creating openings (contact holes) through it, allowing thermal conduction paths to be established in specific locations while maintaining electrical insulation in other areas. This segmentation enables selective thermal management without compromising the overall electrical isolation function of the oxide layer.
Solution Approach 2:
Thermal conduction structures (such as metal fills or conductive materials) are introduced as intermediary elements between the oxide layer and substrate. These intermediaries provide efficient thermal pathways while the oxide layer continues to provide electrical insulation, thus mediating between the conflicting requirements of thermal conduction and electrical insulation.
2Temperature
If thermal substrate contacts are added to improve heat dissipation, then cooling efficiency is improved, but device complexity increases
Solution Approach 1:
The thermal substrate contacts are designed to serve multiple functions: they provide thermal conduction from the transistor to the substrate, and can also serve as electrical connection points or be integrated with existing interconnection structures. This multi-functionality reduces the need for separate dedicated thermal management structures, thereby limiting the increase in device complexity.
Solution Approach 2:
The thermal conduction function is merged with existing device structures such as interconnection vias or contact holes. By combining thermal management functionality with already-present structural elements, the patent avoids adding completely separate components, thus improving cooling efficiency while minimizing the increase in overall device complexity.
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 effectively increases the cooling rate of integrated circuits, reducing the negative consequences of overclocking and extending the operational time before active cooling systems are needed, thus protecting the circuits from high temperature conditions.
Implementation Method 1
thermal substrate contact extending through the layer of semiconductor material and the oxide layer, and against a top surface of the substrate... enhancing both downward and upward thermal conduction
Implementation Method 2
The oxide layer acts as a thermal insulator, reducing the heat diffusion away from the generation locations, e.g., the transistors, of the integrated circuit
Data Source
AI summary
An integrated circuit includes an oxide layer over a substrate; a layer of semiconductor material over the oxide layer and which includes a P-well, an N-well, and a channel of a transistor; and a thermal substrate contact extending through the layer of semiconductor material and the oxide layer, and against a top surface of the substrate. A thermal substrate contact increases the ability to remove heat produced from the integrated circuit transistors out of the integrated circuit. A thermal substrate contact which traverses the oxide layer over a substrate provides a secondary path for heat out of an integrated circuit (or, alternatively, out of a substrate through the integrated circuit) to cool the integrated circuit.