Heat Spreader Structure With Variable BLT for IC Hot Spots

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Solution Overview

Problem

Current semiconductor packaging technologies face challenges in thermal management, including maintaining operating temperature within specified ranges, efficient heat transfer, and preventing delamination due to thermos-mechanical stress and environmental factors, which affects the reliability and longevity of integrated circuits.

Innovation Solution

The semiconductor device incorporates a heat spreader structure with strategically adjusted bond line thickness (BLT) between the integrated circuit and cooling components, utilizing thermal interface materials (TIM) to optimize heat transfer and minimize delamination risks, featuring a protrusion design that enhances thermal conductivity and mechanical support.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If conventional packaging structures are used, then manufacturing is simpler, but thermal resistance increases and heat transfer efficiency decreases

Engineering Contradiction:
Improvethermal resistanceVSAvoidpackaging structure complexity
Core Design Contradiction:
TemperatureVSDevice complexity

Solution Approach 1:

The patent applies local quality by varying the bond line thickness of the thermal interface material in different regions. The BLT is reduced in areas with high heat flux (hot spots) to minimize thermal resistance where it is most critical, while maintaining adequate BLT in other areas for mechanical stability. This localized optimization allows the packaging structure to achieve superior thermal performance without requiring complete redesign of the entire package.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent segments the thermal management system into multiple functional layers including the semiconductor die, thermal interface material with variable BLT, heat spreader, and heat sink. This segmentation allows each layer to be optimized independently for its specific function while working together as an integrated thermal management system, resolving the contradiction between thermal performance and structural complexity.

Inventive Principle:
Principle #1Segmentation

2Temperature

If thin bond line thickness is used to reduce thermal resistance, then heat transfer improves, but mechanical stability and delamination resistance worsen

Engineering Contradiction:
Improvethermal resistanceVSAvoiddelamination resistance
Core Design Contradiction:
TemperatureVSReliability

Solution Approach 1:

The patent resolves this contradiction by applying local quality through spatially variable bond line thickness. Thin BLT is applied only in regions where heat flux is highest and thermal resistance is most critical, while thicker BLT is maintained in regions requiring mechanical stability and delamination resistance. This localized approach allows the system to achieve low thermal resistance without sacrificing overall mechanical reliability.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent changes the parameter of bond line thickness from a uniform value to a variable value that changes according to the local thermal and mechanical requirements. By adjusting the BLT parameter across different regions of the packaging structure, the system simultaneously optimizes for both heat transfer efficiency and mechanical stability, resolving the contradiction between these two opposing requirements.

Inventive Principle:
Principle #35Parameter changes

3Temperature

If uniform bond line thickness is used, then manufacturing is easier, but thermal performance at hot spots is insufficient

Engineering Contradiction:
Improveheat transfer efficiencyVSAvoidbond line thickness control
Core Design Contradiction:
TemperatureVSEase of manufacture

Solution Approach 1:

The patent implements local quality by specifying different bond line thickness values for different regions of the packaging structure. Areas with high heat flux densities have reduced BLT to maximize heat transfer, while other areas maintain adequate BLT for mechanical support. This regional optimization improves thermal performance at hot spots while the patent acknowledges the increased manufacturing complexity required to achieve the variable thickness profile.

Inventive Principle:
Principle #3Local quality

4Reliability

If thick bond line thickness is used, then mechanical stability improves, but thermal resistance increases and heat dissipation worsens

Engineering Contradiction:
Improvemechanical stabilityVSAvoidthermal resistance
Core Design Contradiction:
ReliabilityVSTemperature

Solution Approach 1:

The patent resolves this contradiction by applying thick BLT only in regions where mechanical stability is the primary concern and heat flux is lower, while using thin BLT in regions where heat dissipation is critical. This spatial differentiation allows the system to maintain mechanical integrity through adequate thickness in support areas while achieving low thermal resistance through reduced thickness in heat transfer areas.

Inventive Principle:
Principle #3Local quality

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 effectively reduces thermal resistance, minimizes the risk of overheating and delamination, and enhances the reliability and longevity of semiconductor devices by optimizing heat transfer and mechanical stability.

Implementation Method 1

utilizing thermal interface materials (TIM) to optimize heat transfer

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

heat spreader structure with strategically adjusted bond line thickness (BLT) between the integrated circuit and cooling components

Methodology Applied
Scientific EffectThermal radiation: Thermal Radiation

Implementation Method 3

efficient heat transfer from the IC to the package, which in turn needs to be dissipated to the environment

Methodology Applied
Scientific EffectConvection: Convection

Data Source

PatentEP4456128A1Thermal management systems and methods for semiconductor devices
Publication Date: 2024.10.30 AVAGO TECHNOLOGIES INTERNATIONAL SALES PTE LTD
  • EP4456128A1 patent drawingFigure 1A~1B
  • EP4456128A1 patent drawingFigure 2
  • EP4456128A1 patent drawingFigure 3

AI summary

The present invention is directed to semiconductor devices and integrated circuit packaging. In a specific embodiment, a semiconductor device with a heat spreader structure is provided. The heat spreader is configured to couple to a second layer to establish an effective thermal dissipation path for heat generated from a hot spot of a circuit. The second layer comprises a first portion and a second portion. The first portion is coupled to the hot spot. The heat spreader comprises a third portion and a fourth portion. The third portion comprises a protrusion coupled to the first portion via a first side surface. There are other embodiments as well.