3D Power Distribution Grid Layout for Better Heat Removal
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Solution Overview
Problem
Three-dimensional integrated circuits (3D-ICs) face significant challenges in heat removal due to increased power density and high thermal resistance, particularly in stacked configurations where heat transfer from semiconductor layers to heat sinks is inefficient, often relying on non-conductive materials like insulators that hinder effective heat spreading.
Innovation Solution
The implementation of thermally conductive materials and structures, such as heat spreaders, thermally conductive shallow trench isolation, pre-metal dielectric regions, and etch stop layers, along with thermal contacts and vias, to enhance heat transfer pathways and reduce thermal resistance within the 3D-IC architecture.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple layers of transistors are stacked in 3D configuration, then transistor density and performance are improved, but heat removal becomes significantly more difficult due to increased power density and thermal resistance
Solution Approach 1:
The patent introduces vertical thermal conduction paths through the stacked layers by integrating thermally conductive materials in the interlayer dielectric regions and via structures. This transforms the heat removal problem from a 2D surface issue to a 3D volumetric solution, allowing heat to be conducted vertically from upper transistor layers to lower heat sink structures, thereby resolving the thermal management challenge in 3D stacked configurations
Solution Approach 2:
The patent employs composite material structures combining thermally conductive fillers (such as metal particles or nanotubes) embedded in dielectric matrices within the interlayer regions. These composite materials provide both electrical insulation and enhanced thermal conduction pathways, enabling effective heat transfer through the stacked layers while maintaining the functional integrity of the transistor structure
2Reliability
If non-conductive insulator materials are used for isolation, then electrical insulation is achieved, but heat spreading is hindered due to low thermal conductivity
Solution Approach 1:
The patent uses composite dielectric materials consisting of thermally conductive fillers dispersed in electrically insulating matrices within the interlayer dielectric regions. These composites simultaneously provide electrical insulation to prevent current leakage between layers and thermal conduction to facilitate heat spreading, thereby resolving the contradiction between electrical isolation and thermal management
Solution Approach 2:
The patent applies different material properties to different regions: the bulk dielectric material provides electrical insulation, while localized regions containing thermally conductive via structures and filler-rich zones provide enhanced heat conduction pathways. This spatial differentiation of material properties allows simultaneous achievement of electrical isolation and thermal management in the same structure
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
These measures significantly improve heat removal efficiency by creating effective thermal conduction paths and reducing thermal resistance, allowing for better management of heat buildup in 3D-ICs, maintaining desirable temperature levels across the circuitry.
Implementation Method 1
The implementation of thermally conductive materials and structures, such as heat spreaders, thermally conductive shallow trench isolation, pre-metal dielectric regions, and etch stop layers, along with thermal contacts and vias, to enhance heat transfer pathways and reduce thermal resistance within the 3D-IC architecture
Data Source
AI summary
A 3D device includes a first level including a first single crystal layer with control circuitry, where the control circuitry includes first single crystal transistors; a first metal layer atop first single crystal layer; a second metal layer atop the first metal layer; a third metal layer atop the second metal layer; second level (includes a plurality of second transistors) atop the third metal layer; a fourth metal layer disposed above the one second level; a fifth metal layer atop the fourth metal layer, where the second level includes at least one first oxide layer overlaid by a transistor layer and then overlaid by a second oxide layer; a global power distribution grid, which includes the fifth metal layer; a local power distribution grid including at least one second transistor, the thickness of the fifth metal layer is at least 50% greater than the thickness of the second metal layer.