Thermal Substrate Contacts Through Oxide Isolation in ICs
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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 increased temperatures and reduced lifespan, especially when overclocked, as heat generated by transistors is poorly conducted away from 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 life 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 performance is improved, but heat dissipation capability 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 preserving the electrical insulation function in other areas. The oxide layer remains intact in most regions for leakage prevention, but is locally removed to enable heat dissipation.
Solution Approach 2:
Different regions of the oxide layer have different properties: most areas maintain full oxide coverage for electrical insulation, while specific contact regions have the oxide removed or thinned to create thermal conduction paths. This local differentiation allows simultaneous achievement of electrical performance and thermal management.
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 serve multiple functions: they provide thermal conduction paths for heat dissipation, act as electrical connections to substrate contacts, and can be integrated with existing interconnection structures. This multi-functionality reduces the need for separate dedicated thermal management components.
Solution Approach 2:
The thermal management function is merged with the existing electrical interconnection structure. Thermal substrate contacts are combined with electrical substrate contacts, and thermal conduction paths are integrated with metal interconnection layers, eliminating the need for separate thermal management infrastructure.
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 effects of overclocking and extending the operational time before active cooling systems are needed, thus protecting the circuits from high temperature conditions.
Implementation Method 1
enhancing both downward and upward thermal conduction to increase cooling efficiency
Implementation Method 2
The oxide layer acts as a thermal insulator, reducing the heat diffusion away from the generation locations
Data Source
AI summary
An integrated circuit includes a substrate and a semiconductor material layer over the substrate. The integrated circuit includes a first source structure in the semiconductor material layer. The first source structure includes a first doped well. The integrated circuit includes a drain structure in the semiconductor material layer. The drain structure includes a second doped well. The integrated circuit includes a second source structure in the semiconductor material layer. The second source structure includes a third doped well. The drain structure is between the first source structure and the second source structure. The integrated circuit includes a first deep trench isolation (DTI) extending through the first doped well; and a first thermal contact extending through the first DTI. The thermal contact is in direct contact with the substrate. The first DTI is between the thermal contact and the first doped well.