Heat Spreading Layer in Composite IC Die Structure

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Solution Overview

Problem

In microelectronic packages, especially those with vertically integrated IC dies, heat spreading and dissipation are limited due to the use of silica-filled organics with low thermal conductivity and design constraints of metallization layers, leading to thermal challenges as die size shrinks and power density increases.

Innovation Solution

A heat spreading material is integrated at or near the bond interface between IC dies in a composite IC die structure, specifically designed to enhance lateral and vertical thermal spreading by using materials with higher thermal conductivity, such as graphene or carbon nanotubes, and patterned to direct heat dissipation pathways.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If microbumps are added between die to promote thermal spreading, then thermal spreading is improved, but the spreading is limited to the area of the smallest component and minimum assembly pitch

Engineering Contradiction:

Improvethermal spreadingVSAvoidspreading area

Core Design Contradiction:

TemperatureVSArea of stationary object

Solution Approach 1:

The patent transitions from lateral thermal spreading (2D plane) to vertical thermal spreading (3D dimension) by implementing heat spreading layers between stacked IC dies. This allows heat to spread in the vertical dimension through the stack, bypassing the area limitations of lateral spreading approaches.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The heat spreading layers are integrated within the existing IC die stack structure, nesting the thermal management function between the IC dies. The heat spreading layers are positioned within the bond interfaces of the die stack, utilizing the existing vertical arrangement to achieve thermal spreading without adding lateral space requirements.

Inventive Principle:

Principle #7Nested doll (Nesting)

2Temperature

If BEOL metal layers are designed to improve heat flow, then thermal spreading is improved, but the patterns are limited by design rules for metallization layers

Engineering Contradiction:

Improveheat flowVSAvoidpattern design flexibility

Core Design Contradiction:

TemperatureVSAdaptability or versatility

Solution Approach 1:

The thermal management function is segmented from the electrical interconnect function. Instead of using BEOL metal layers that must satisfy both electrical and thermal requirements with limited pattern flexibility, the patent introduces dedicated heat spreading layers that can be independently optimized for thermal performance without being constrained by electrical design rules.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The heat spreading layers act as intermediary thermal management components between the IC dies and the external thermal management structure. These layers provide a dedicated thermal conduction path that is independent of the electrical interconnect structure, allowing thermal and electrical designs to be optimized separately.

Inventive Principle:

Principle #24Intermediary (Mediator)

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 solution improves thermal spreading beyond conventional limits, effectively managing heat generated in high-density devices by directing it through predetermined pathways, enhancing the performance and reliability of microelectronic devices.

Implementation Method 1

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentUS11581238B2Heat spreading layer integrated within a composite IC die structure and methods of forming the same

Publication Date: 2023.02.14 INTEL CORP

AI summary

A heat spreading material is integrated into a composite die structure including a first IC die having a first dielectric material and a first electrical interconnect structure, and a second IC die having a second dielectric material and a second electrical interconnect structure. The composite die structure may include a composite electrical interconnect structure comprising the first interconnect structure in direct contact with the second interconnect structure at a bond interface. The heat spreading material may be within at least a portion of a dielectric area through which the bond interface extends. The heat spreading material may be located within one or more dielectric materials surrounding the composite interconnect structure, and direct a flow of heat generated by one or more of the first and second IC dies.