Base Die TSV Heat Path for Stacked Die Thermal Isolation
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Solution Overview
Problem
Legacy stacked die architectures face significant thermal performance issues due to die-to-die heating, where thermal energy generated by a base die is propagated to top dies, leading to diminished thermal performance and operational constraints, and the polymer overmold used for cooling lacks effective thermal conductivity, causing warping and inefficient heat dissipation.
Innovation Solution
Incorporating thermally conductive features such as through silicon vias (TSVs) filled with high thermal conductivity materials like copper, silver, or gold, and using dummy dies with TSVs to route thermal energy away from top dies, either within passive areas of base dies or as separate dummy dies, to create a lower thermal resistance path for heat dissipation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If thermal energy is routed through top dies in legacy stacked die architectures, then die-to-die heating occurs, but thermal performance diminishes and operational constraints increase
Solution Approach 1:
The patent segments the thermal conduction path by introducing dedicated thermal conduction channels (through-silicon vias filled with thermally conductive material) that are spatially separated from the electrical interconnect paths. This segmentation allows thermal energy to be conducted independently through specific regions of the base die without requiring heat to propagate through the top dies, thereby maintaining thermal performance while eliminating operational constraints associated with die-to-die heating.
Solution Approach 2:
The patent introduces an intermediary thermal conduction structure consisting of through-silicon vias filled with high thermal conductivity material (such as copper or diamond-like carbon). These intermediary channels act as dedicated heat sinks that intercept thermal energy at the base die level and conduct it directly to the substrate, preventing heat propagation to top dies and resolving the contradiction between thermal performance and operational reliability.
2Temperature
If polymer overmold is used for cooling, then structural coverage is provided, but thermal conductivity is insufficient causing warping and inefficient heat dissipation
Solution Approach 1:
The patent fundamentally changes the thermal conduction parameter by replacing the polymer overmold material with metal-based thermal conduction channels (such as copper-filled through-silicon vias). This parameter change increases thermal conductivity by several orders of magnitude, enabling efficient heat dissipation while the metallic structure's dimensional stability prevents warping issues associated with polymer materials.
Solution Approach 2:
The patent employs composite material structures where through-silicon vias are filled with high thermal conductivity materials (copper, diamond-like carbon) within the silicon substrate. This composite approach combines the structural integrity of silicon with the superior thermal conductivity of metal fillers, creating a thermal management solution that achieves both efficient heat dissipation and dimensional stability without warping.
3Temperature
If TSVs are used to route thermal energy away from top dies, then thermal resistance is reduced, but manufacturing complexity increases
Solution Approach 1:
The patent applies multi-functionality to the through-silicon via structure, which serves both electrical interconnection and thermal conduction functions. By designing TSVs that can simultaneously carry electrical signals and conduct thermal energy (when filled with thermally conductive material), the patent reduces the need for separate dedicated thermal pathways, thereby lowering manufacturing complexity while achieving reduced thermal resistance.
Solution Approach 2:
The patent incorporates thermal conduction features into the base die during the initial die fabrication process, before packaging and assembly. The through-silicon vias are formed and filled with thermally conductive material as part of the standard semiconductor manufacturing flow, allowing thermal management features to be integrated preliminarily without requiring additional complex post-processing steps, thus minimizing manufacturing complexity increases.
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 overall thermal resistance, enhances cooling routes for base dies, allows for higher power operation without reaching maximum chip temperatures, and decreases the power required for cooling, thereby improving the operational quality and thermal performance of stacked die packages.
Implementation Method 1
TSVs in passive areas of a base die route thermal energy away from top dies thermally coupled with the base die
Implementation Method 2
a thermal block with one or more thermal conductivity features that thermally couple the first side of the first die to the first side of the thermal block
Data Source
AI summary
Embodiments of the present disclosure may generally relate to systems, apparatuses, techniques, and/or processes directed to packages that include stacked dies that use thermal conductivity features including thermally conductive through silicon vias (TSVs) filled with thermally conductive material located in passive areas of a first die to route heat from a first die away from a second die that is coupled with the first die. In embodiments, the first die may be referred to as a base die. Embodiments may include thermal blocks in the form of dummy dies that include TSVs at least partially filled with thermal energy conducting material such as copper, solder, or other alloy.