Base Die Thermal TSV Layout for Stacked Die Heat Isolation

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Solution Overview

Problem

Legacy stacked die architectures face significant thermal constraints 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 issues, 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 thermally coupled with base dies to route thermal energy away from top dies, either through the TSVs or passive areas of the base die, to reduce thermal resistance and enhance cooling efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If legacy stacked die architectures are used with polymer overmold for cooling, then device integration is achieved, but thermal conductivity is insufficient causing warping and inefficient heat dissipation

Engineering Contradiction:

Improveheat dissipation efficiencyVSAvoidwarping and thermal performance

Core Design Contradiction:

TemperatureVSReliability

Solution Approach 1:

The patent changes the thermal conductivity parameter of the overmold material by replacing polymer with thermally conductive materials such as metal-filled epoxies, ceramics, or metal matrices. This parameter change enables efficient heat dissipation while maintaining structural integrity and preventing warping, directly resolving the thermal management contradiction in stacked die architectures.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent employs composite materials by combining thermally conductive fillers (such as metal particles, ceramic beads, or graphite flakes) with epoxy resins or polymer matrices. This creates a composite overmold material that achieves both the mechanical properties needed for packaging and the high thermal conductivity required for efficient heat dissipation, eliminating the warping and thermal performance issues.

Inventive Principle:

Principle #40Composite materials

2Strength

If thermal energy is routed through top dies in legacy architectures, then die-to-die coupling is maintained, but thermal constraints diminish operational performance

Engineering Contradiction:

Improvedie-to-die thermal couplingVSAvoidoperational performance

Core Design Contradiction:

StrengthVSProductivity

Solution Approach 1:

The patent extracts the thermal management function from the top dies by introducing dedicated thermal management structures (such as thermal vias, heat spreaders, or thermally conductive underfills) that route heat away from the top dies through separate pathways. This extraction allows the top dies to maintain their computational function without being constrained by thermal accumulation, thereby improving operational performance while preserving necessary thermal coupling through controlled interfaces.

Inventive Principle:

Principle #2Taking out (Extraction)

3Volume of moving object

If reduced-size system-in-package components are used, then end product size is reduced, but thermal management becomes more challenging

Engineering Contradiction:

Improvepackage sizeVSAvoidthermal density

Core Design Contradiction:

Volume of moving objectVSTemperature

Solution Approach 1:

The patent implements nested thermal management structures where thermally conductive materials are embedded within the package layers (such as metal-filled epoxies between dies, thermal vias through substrate layers, or heat spreaders integrated into existing package structures). This nesting approach provides effective thermal management pathways within the compact package volume, enabling heat dissipation without increasing overall package size.

Inventive Principle:

Principle #7Nested doll (Nesting)

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, allows stacked die architectures to operate at higher power levels without reaching maximum chip temperatures, and decreases the power required for cooling, thereby improving the operational quality and reliability of the package.

Implementation Method 1

TSVs that are at least partially filled with thermally conductive material to route thermal energy away from a top die

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

route thermal energy away from a top die thermally coupled with the base die to a surface of the dummy die opposite the base die

Methodology Applied

Scientific EffectThermal energy transfer: Conduction (thermal)

Data Source

PatentUS11854935B2Enhanced base die heat path using through-silicon vias

Publication Date: 2023.12.26 INTEL CORP

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.