On-Chip Embedded Thermal Antenna for Semiconductor Cooling
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Solution Overview
Problem
Low dielectric constant materials in semiconductor chips hinder heat transfer from active devices to heat sinks, exacerbated by stacked chip designs and joule heating of interconnect wires, necessitating an efficient cooling solution that balances thermal conductivity and area penalties.
Innovation Solution
The method involves forming a multilayer semiconductor chip with active structures and thermally conductive inactive structures aligned to create a continuous thermal path, using electrically isolated and thermally conductive materials to enhance heat dissipation without significant area increases, allowing for the integration of additional stacked chips with aligned thermal conductors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If low dielectric constant materials are used in multilevel VLSI circuits, then signal integrity and electrical isolation are improved, but heat transfer capability deteriorates
Solution Approach 1:
The patent divides the interconnect structure into multiple layers with alternating low-k dielectric layers and high-thermal-conductivity filler layers. Each layer is segmented into regions with different material properties - standard low-k regions for signal routing and filler regions for thermal management. This segmentation allows simultaneous achievement of electrical isolation and heat dissipation by assigning different functional priorities to different spatial segments.
Solution Approach 2:
The patent implements local quality by creating regions with high thermal conductivity fillers (such as diamond, carbon nanotubes, or metal particles) embedded in the low-k dielectric material at specific locations where heat generation is highest. These localized high-conductivity regions are positioned near active devices and interconnect hotspots, while other regions maintain standard low-k properties for optimal electrical performance. This spatial variation in material quality enables targeted thermal management without compromising overall signal integrity.
2Productivity
If stacked chip design is implemented, then device density and integration are improved, but thermal management complexity increases
Solution Approach 1:
The patent merges thermal management functionality directly into the interconnect structure by integrating high-thermal-conductivity fillers within the low-k dielectric layers. This combination eliminates the need for separate thermal management components or additional processing steps, as the interconnect layers themselves serve dual purposes: electrical signal transmission and heat dissipation. The merged structure reduces overall system complexity while enabling stacked chip designs.
Solution Approach 2:
The patent addresses thermal management in stacked chip designs by extending the thermal conduction pathways into the vertical dimension. High-thermal-conductivity fillers are arranged in columns or arrays that span multiple interconnect layers, creating three-dimensional thermal highways that conduct heat away from active devices through the vertical stack. This dimensional approach to thermal management efficiently handles heat dissipation in high-density stacked configurations without increasing lateral footprint.
3Temperature
If thermally conductive inactive structures are added to create thermal paths, then heat dissipation is improved, but manufacturing complexity increases
Solution Approach 1:
The patent makes the inactive filler structures serve multiple functions simultaneously. These structures provide thermal conduction, electrical isolation, mechanical support, and stress distribution. By designing the filler geometry and material composition to fulfill multiple roles, the patent eliminates the need for separate components for each function, thereby simplifying the overall manufacturing process despite the enhanced thermal management capabilities.
Solution Approach 2:
The patent incorporates high-thermal-conductivity fillers during the dielectric layer formation process itself, before subsequent interconnect fabrication steps. The fillers are embedded in the low-k material during the same deposition or infiltration step used to create the dielectric layers, rather than requiring separate post-processing steps. This preliminary integration of thermal management features into the base fabrication flow minimizes additional manufacturing complexity.
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 maximizes thermal conductivity while minimizing electrical noise and crosstalk, enabling effective heat transfer through the chip layers and across stacked chips without requiring extensive metal fill or hot spot analysis, thus improving thermal performance and maintaining manufacturing and operational balance.
Implementation Method 1
The first inactive structures and the second inactive structures form a continuous thermally conductive path through the semiconductor chip
Implementation Method 2
The joule heating of interconnect wires and vias can also be a major thermal source that needs to be addressed
Data Source
AI summary
An apparatus comprises a first layer within a semiconductor chip having active structures electrically connected to other active structures and having electrically isolated first inactive structures. A second layer within the semiconductor chip is physically connected to the first layer. The second layer comprises an insulator and has second inactive structures. The first inactive structures are physically aligned with the second inactive structures.