Stacked Semiconductor Assembly With Lateral Heat-Spreading Layers
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Solution Overview
Problem
Semiconductor device assemblies face thermal management challenges due to heat generated by power-intensive logic dies, which can exceed the operating temperature tolerance of adjacent memory dies, leading to unreliable operation.
Innovation Solution
Incorporating layers of thermally conductive material with high conductivity in the x-y plane and low conductivity in the z-plane between semiconductor dies to laterally conduct heat away from the stack, thereby isolating temperature-sensitive dies from heat-generating dies while effectively extracting heat.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If heat dissipating structures such as lids or heat sinks are provided over semiconductor dies, then heat exchange between package and environment is improved, but device complexity increases
Solution Approach 1:
A thermally conductive underfill material is introduced as an intermediary substance between the logic die and memory dies. This underfill material has high thermal conductivity to facilitate lateral heat transfer away from the memory dies, effectively managing thermal conditions without requiring additional external heat dissipation structures
Solution Approach 2:
The underfill material is applied specifically in the region between the logic die and memory dies where thermal management is critical. The material exhibits directionally selective thermal conductivity with higher conductivity in the lateral direction (parallel to die surface) than in the vertical direction, creating localized thermal pathways that redirect heat away from temperature-sensitive components
2Productivity
If power density of semiconductor devices is increased, then productivity is improved, but thermal management becomes more difficult
Solution Approach 1:
The thermal management approach transitions from one-dimensional vertical heat flow (through heat sinks from top surface) to two-dimensional lateral heat flow within the package plane. The underfill material creates thermal pathways that conduct heat laterally from the memory dies toward the logic die or package edges, enabling heat dissipation through additional spatial dimensions
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 thermal performance and reliability by preventing vertical heat transfer, allowing for increased power density without compromising the operation of temperature-sensitive dies.
Implementation Method 1
a layer of thermally conductive material can be disposed between a first semiconductor die and a lowermost one of the second semiconductor dies. The thermally conductive material can be configured to conduct heat generated by one or more of the semiconductor dies laterally outward
Data Source
AI summary
Semiconductor device assemblies are provided with one or more layers of thermally conductive material disposed between adjacent semiconductor dies in a vertical stack. The thermally conductive material can be configured to conduct heat generated by one or more of the semiconductor dies in laterally outward towards an outer edge of the assembly. The layer of thermally conductive material can comprise one or more allotropes of carbon, such as diamond, graphene, graphite, carbon nanotubes, or a combination thereof. The layer of thermally conductive material can be provided via deposition (e.g., sputtering, PVD, CVD, or ALD), or via adhering a film comprising the layer of thermally conductive material to one or more of the semiconductor dies.