3D Semiconductor Device Thermal Shielding
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Solution Overview
Problem
In 3D stacked integrated circuits, the degradation of wire performance with scaling and the challenge of heat removal due to increased power density and thermal resistance hinder the efficiency and reliability of the devices.
Innovation Solution
The implementation of a 3D semiconductor device structure with a heat spreading and conducting shield layer between sensitive metal interconnects and the annealing region, utilizing optical annealing techniques to repair crystal lattice damage without damaging underlying metal layers, and an optimized power distribution network to enhance heat removal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If optical annealing is used to repair crystal lattice damage, then defect-free crystalline semiconductor layers are achieved, but high temperature may damage underlying metal interconnects
Solution Approach 1:
A shield layer is introduced as an intermediary component between the semiconductor layer being annealed and the metal interconnects below. This shield layer absorbs or blocks the thermal energy from the optical annealing process, preventing it from reaching and damaging the metal interconnects while allowing the semiconductor layer to be properly annealed to achieve defect-free crystalline structure
Solution Approach 2:
The patent applies selective shielding where the shield layer is positioned only in specific regions where metal interconnects are present and vulnerable to thermal damage. This allows optical annealing to proceed in areas where it is needed while protecting only the specific locations where metal layers exist, maintaining local thermal protection without compromising overall annealing effectiveness
2Speed
If 3D stacking is implemented to reduce wire lengths, then wiring delay is reduced, but heat removal becomes more difficult due to increased power density and thermal resistance
Solution Approach 1:
The patent extracts the heat management function from the standard interconnect structure by introducing dedicated heat spreader layers and thermal vias. These specialized thermal pathways are separated from the electrical interconnect function, allowing heat to be actively removed from the dense 3D stack through dedicated thermal management structures rather than relying on the metal interconnects alone
Solution Approach 2:
The patent employs composite interconnect structures that combine materials with different thermal and electrical properties. For example, using tungsten for via structures provides both electrical connectivity and superior thermal conductivity compared to traditional copper, creating a composite system that simultaneously addresses both electrical performance and heat removal requirements in the 3D stacked architecture
3Ease of manufacture
If hydrogen ion implantation is used to form detaching layer, then layer transfer is enabled, but crystal lattice structure is damaged requiring high temperature thermal treatment
Solution Approach 1:
The patent introduces a dedicated detaching layer as an intermediary between the donor and acceptor wafers during layer transfer. This detaching layer is specifically designed to be implanted with hydrogen ions to create a weak bonding plane that allows for clean separation. The detaching layer absorbs the damage from ion implantation, protecting the crystal lattice structures of the semiconductor layers being transferred while still enabling effective layer separation
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 defect-free crystalline semiconductor layers at low temperatures, improves heat dissipation, and maintains the integrity of metal interconnects, thereby enhancing the performance and reliability of 3D ICs.
Implementation Method 1
heat spreading and conducting shield layer
Implementation Method 2
heat spreading and conducting shield layer
Implementation Method 3
utilizing optical annealing techniques to repair crystal lattice damage
Implementation Method 4
utilizing optical annealing techniques
Implementation Method 5
optimized power distribution network to enhance heat removal
Data Source
AI summary
A 3D semiconductor device, the device including: a first single crystal layer including a plurality of first transistors; at least one first metal layer interconnecting the plurality of first transistors, where the interconnecting includes forming a plurality of logic gates; a plurality of second transistors overlaying the first single crystal layer; a second metal layer overlaying the plurality of second transistors; a plurality of third transistors overlaying the second transistors; a third metal layer overlaying the plurality of third transistors; and a connective metal path between the third metal layer and at least one of the first transistors, where at least one of the plurality of third transistors is aligned to at least one of the plurality of first transistors with less than 40 nm alignment error, where the first metal layer is powered by a first voltage and the second metal layer is powered by a second voltage.