3D Logic-Memory Stack With Thermal Isolation and Hybrid Bonding
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Solution Overview
Problem
The performance and functionality of Integrated Circuits (ICs) are hindered by degrading wire performance due to scaling, which affects power consumption and efficiency, and existing 3D stacking techniques face challenges in layer transfer and thermal isolation, limiting the integration of diverse semiconductor devices.
Innovation Solution
The development of 3D semiconductor devices with layer transfer technologies that enable the reuse of donor wafers and the integration of single crystal silicon layers with thermal isolation, allowing for the bonding of logic and memory circuits with oxide-to-oxide and metal-to-metal bonds, and the use of SiGe as a sacrificial layer for epitaxial-based layer transfer, facilitating heterogeneous integration and reduced thermal budgets.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If scaling is applied to reduce component sizes, then transistor performance and density improve, but wire performance degrades
Solution Approach 1:
The patent transitions from 2D planar integration to 3D vertical stacking, arranging transistors and interconnects in multiple layers. This dimensional change allows transistors to be placed closer together vertically, improving density without further lateral scaling, while interconnects are organized in a hierarchical 3D network that reduces wire lengths and improves signal integrity.
2Speed
If 3D stacking is implemented to reduce wire lengths, then wiring delay decreases, but layer transfer and thermal isolation challenges arise
Solution Approach 1:
The patent segments the 3D integrated circuit into multiple independent layers or stacks, each containing specific functional blocks. These segmented layers can be fabricated separately using standard CMOS processes, then transferred and stacked using TSV technology. This segmentation reduces the complexity of monolithic 3D fabrication while enabling independent optimization of each layer.
Solution Approach 2:
The patent introduces through-silicon vias (TSVs) as intermediary structures that penetrate through substrate layers to establish vertical interconnections. TSVs serve as the mediator that enables layer transfer and stacking by providing mechanical support and electrical connectivity between otherwise independent layers, simplifying the overall layer integration process.
3Adaptability or versatility
If multiple layers are stacked to integrate diverse devices, then functionality increases, but thermal management becomes difficult
Solution Approach 1:
The patent implements localized thermal management strategies by integrating heat sinks, thermal vias, and cooling channels at specific hot spots within the 3D structure. Different regions of the device receive customized thermal treatment based on their power density requirements, allowing effective heat dissipation in high-power areas while maintaining overall device functionality.
Solution Approach 2:
The patent employs composite material structures combining different thermal conductivity materials in the 3D stack. High-thermal-conductivity materials are used in heat dissipation paths and thermal interface layers, while low-thermal-conductivity materials provide thermal isolation between sensitive layers. This composite approach enables simultaneous heat removal from hot spots and thermal protection of temperature-sensitive components.
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 enhances the performance and efficiency of ICs by reducing wire lengths, improving thermal management, and enabling the integration of diverse semiconductor devices without process temperature restrictions, leading to increased yield and reduced development costs.
Implementation Method 1
the single crystal silicon includes an area, and where the area is greater than 1,000 mm2
Data Source
AI summary
A 3D semiconductor device comprising: a first level; and a second level, wherein said first level comprises single crystal silicon and a plurality of logic circuits, wherein said plurality of logic circuits each comprise first transistors, wherein said second level is disposed above said first level and comprises a plurality of arrays of memory cells, said second level comprises a plurality of second transistors, wherein each of said memory cells comprises at least one of said second transistors, wherein said first level is bonded to said second level, wherein said bonded comprises regions of oxide to oxide bonds, wherein said bonded comprises regions of metal to metal bonds; and a thermal isolation layer disposed between said first level and said second level, wherein said thermal isolation layer provides a greater than 20° C. differential temperature between said first level and said second level during nominal operation of said device.