Protruding TSV Tips for IC Heat Dissipation
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Solution Overview
Problem
Conventional heat dissipation methods for integrated circuits (ICs) are inefficient as they require heat to be channeled through the full thickness of the substrate from the frontside, where hotspots are located, to the bottomside for dissipation, leading to thermal resistance and uneven temperature distribution across the die.
Innovation Solution
The use of through-silicon vias (TSVs) with a plurality of dummy TSVs that extend from the topside semiconductor surface to the bottomside, providing a higher thermal conductivity path and increased surface area for radiative heat transfer, utilizing metals like copper for improved heat transfer and dissipation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If heat is channeled through the full thickness of the substrate from the frontside to the bottomside for dissipation, then heat dissipation is achieved, but thermal resistance increases and temperature distribution becomes uneven
Solution Approach 1:
The patent extends heat dissipation from a two-dimensional path (frontside to bottomside through substrate thickness) to a three-dimensional structure by adding protruding TSV tips that extend into the packaging material below the die. This creates additional thermal pathways in the vertical dimension, reducing thermal resistance and improving temperature distribution uniformity across the die.
Solution Approach 2:
The heat dissipation function is segmented into multiple independent TSV structures rather than relying on a single substrate path. Each TSV acts as an independent thermal conduit, and the collective array of TSVs provides distributed heat removal, reducing hotspots and improving overall thermal management effectiveness.
2Loss of energy
If conventional heat spreaders and heat sinks are used, then heat dissipation is enhanced, but the frontside of the die must be used for wiring and heat must be channeled through the full substrate thickness, reducing efficiency
Solution Approach 1:
Instead of channeling heat from the frontside through the substrate to the bottomside, the patent inverts the approach by creating heat dissipation structures (protruding TSV tips) that extend from the bottomside into the packaging material. This allows heat to be conducted directly down through the TSVs without requiring long thermal paths through the substrate, significantly improving heat dissipation efficiency.
Solution Approach 2:
The TSVs with protruding tips act as intermediary thermal conduits between the die and the packaging material. These metal-filled vias provide a high thermal conductivity path that bridges the thermal gap, enabling efficient heat transfer from the die to the surrounding packaging material without requiring the heat to traverse the full substrate thickness.
3Productivity
If more functional blocks are integrated in a single die for system-on-chip designs, then integration density increases, but hotspots are created leading to temperature differences of 5°C to 30°C across the die
Solution Approach 1:
The patent implements localized heat dissipation by positioning TSVs strategically throughout the die, with higher TSV density in regions with high power dissipation (hotspots). This local quality approach allows each region to be cooled according to its specific thermal load, reducing temperature differences across the die while maintaining high integration density.
Solution Approach 2:
The patent changes the thermal parameters of the die structure by introducing metal-filled TSVs with protruding tips that have higher thermal conductivity than the substrate material. This parameter change in thermal conductivity creates efficient heat sinking paths that reduce the temperature rise caused by high-power functional blocks, enabling higher integration density without excessive temperature differences.
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 reduces thermal resistance and enhances heat dissipation by creating a more efficient thermal path and increased surface area for heat transfer, effectively managing temperature variations across the IC die and maintaining reliable operation.
Implementation Method 1
The inner metal core of the TSVs provide reduced thermal resistance for heat transfer from the topside semiconductor surface and the bottomside surface because metals such as copper have a thermal conductivity that is higher as compared to most substrate materials
Implementation Method 2
The protruding TSV tips significantly increase the surface area on the bottomside of the TSV die that significantly improves radiative heat transfer and thus heat dissipation
Data Source
AI summary
An integrated circuit (IC) device includes a substrate having a top surface including substrate pads, and a through substrate via (TSV) die including a semiconductor substrate including a topside semiconductor surface having active circuitry and a bottomside surface. The topside semiconductor surface includes bonding connectors that are coupled to the substrate pads on the top surface of the substrate. A plurality of TSVs include an inner metal core that extends from the topside semiconductor surface to protruding TSV tips which extend out from the bottomside surface. At least one of the plurality of TSVs are dummy TSVs that have their protruding TSV tips exclusive of any electrically connection thereto that provide additional surface area that enhances heat dissipation from the bottomside of the TSV die.