3D Semiconductor Device Thermal Protection via Heat Spreading
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Solution Overview
Problem
In 3D stacked integrated circuits, the degradation of wire performance due to scaling and the challenge of heat removal from high power density layers, which can damage underlying metal interconnects and device layers, necessitates innovative solutions for maintaining performance and functionality while managing thermal issues.
Innovation Solution
The incorporation of a heat spreading or reflecting material layer between sensitive metal interconnects and the annealing process, using optical annealing techniques such as laser-spike anneal, and the implementation of thermal protective structures to prevent damage from high-temperature processing, allowing for defect repair and dopant activation without harming underlying layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If high-temperature annealing is used to repair crystal lattice damage and activate dopants, then defect-free crystalline semiconductor layers are achieved, but underlying metal interconnects and device layers are damaged
Solution Approach 1:
The patent segments the thermal processing function by introducing a heat spreading layer that separates the heat source (laser) from the underlying sensitive layers. This allows localized high-temperature annealing of the semiconductor layer without damaging the metal interconnects below, resolving the contradiction between achieving defect-free crystals and protecting underlying structures from thermal damage
Solution Approach 2:
The heat spreading layer acts as an intermediary between the laser annealing process and the underlying metal interconnects. This intermediate structure absorbs and redistributes the thermal energy, enabling the semiconductor layer to receive sufficient heat for defect repair while preventing excessive heat from reaching and damaging the sensitive metal layers below
2Speed
If 3D stacking is implemented to reduce wire lengths, then wiring delay is reduced, but heat removal becomes more difficult
Solution Approach 1:
The patent applies local quality by implementing heat spreading layers at specific locations within the 3D stack, particularly between layers and at critical hot spots. This localized thermal management approach allows the 3D structure to maintain its compact signal paths while providing targeted heat dissipation where needed, balancing speed improvement with thermal control
Solution Approach 2:
The patent addresses heat removal challenges by adding thermal management structures in the vertical dimension of the 3D stack. Heat spreading layers are inserted between horizontal layers, creating additional thermal pathways in the vertical direction while maintaining the horizontal compactness needed for fast signal transmission
3Object-affected harmful factors
If heat spreading material is added between metal interconnects, then underlying layers are protected from heat damage, but device complexity increases
Solution Approach 1:
The heat spreading layer is designed to perform multiple functions simultaneously: it spreads thermal energy to protect underlying layers, serves as part of the annealing process for the semiconductor layer, and can be integrated with existing device structures. This multi-functionality reduces the net increase in device complexity while achieving thermal protection
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 enables the construction of defect-free crystalline semiconductor layers at lower temperatures, improving transistor performance and reducing thermal resistance, thus enhancing the reliability and efficiency of 3D ICs by protecting sensitive components from heat-related damage.
Implementation Method 1
annealing process, using optical annealing techniques such as laser-spike anneal
Implementation Method 2
incorporation of a heat spreading or reflecting material layer between sensitive metal interconnects
Implementation Method 3
incorporation of a heat spreading or reflecting material layer between sensitive metal interconnects
Data Source
AI summary
A 3D semiconductor device, the device comprising: a first level, wherein said first level comprises a first layer, said first layer comprising first transistors, and wherein said first level comprises a second layer comprising first interconnections; a second level overlaying said first level, wherein said second level comprises a third layer, said third layer comprising second transistors, and wherein said second level comprises a fourth layer comprising second interconnections; and a plurality of connection paths, wherein said plurality of connection paths provides connections from a plurality of said first transistors to a plurality of said second transistors, wherein said second level is bonded to said first level, wherein said bonded comprises oxide to oxide bond regions and metal to metal bond regions, wherein said second level comprises at least one memory array, wherein said third layer comprises crystalline silicon, and wherein said second level comprises at least one SerDes circuit.