Semiconductor Packaging Nano-Structure Layer Thermal Stress

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Solution Overview

Problem

Semiconductor devices face thermal stress and heat radiation issues due to thermal deformation differences between materials, which can lead to reliability deterioration and increased temperature rises with higher packaging densities.

Innovation Solution

A semiconductor packaging structure that incorporates a nano-structure layer with densely arranged spring-shaped nanostructures between the semiconductor chip and conductive members, absorbing thermal deformation and reducing thermal resistance through deformation of these nanostructures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional packaging structures are used with thick joining layers or resin sealing, then thermal stress is reduced, but device complexity and manufacturing complexity increase

Engineering Contradiction:
Improvethermal stress resistanceVSAvoidpackaging structure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent employs a thin film structure consisting of alternating layers of first and second materials with different thermal expansion coefficients. This thin film acts as a flexible buffer that absorbs thermal stress through differential expansion and contraction, eliminating the need for thick joining layers or resin sealing while maintaining stress resistance.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The patent uses a composite structure with multiple layers of different materials (first material and second material) having distinct thermal properties. The composite nature allows the structure to accommodate thermal deformation through the coordinated expansion and contraction of different material layers, providing stress absorption without increased complexity.

Inventive Principle:
Principle #40Composite materials

2Productivity

If packaging density is increased, then productivity improves, but thermal stress increases due to heat generation

Engineering Contradiction:
Improvepackaging densityVSAvoidthermal stress resistance
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The thin film structure with alternating material layers provides a flexible thermal management solution that can be integrated into high-density packaging. The differential thermal expansion of the layered structure absorbs stress generated by increased packaging density, allowing higher productivity without compromising reliability.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The patent changes the thermal parameters of the packaging structure by using materials with different thermal expansion coefficients in alternating layers. This parameter variation enables the structure to adapt to thermal stress conditions arising from high packaging density, maintaining reliability while improving productivity.

Inventive Principle:
Principle #35Parameter changes

3Device complexity

If joining layers are made thinner to reduce device complexity, then manufacturing precision must increase to ensure adequate stress absorption

Engineering Contradiction:
Improvejoining layer thicknessVSAvoidlayer thickness control
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The thin film structure is specifically designed to provide adequate stress absorption functionality at reduced thickness. The alternating layer configuration optimizes the stress management efficiency, allowing thinner overall structure while maintaining or improving stress absorption capability, thus reducing the stringency of manufacturing precision requirements.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The composite layered structure enhances the stress absorption efficiency per unit thickness. By carefully selecting materials with complementary thermal properties, the structure achieves superior stress management in a thinner configuration, reducing the need for extremely precise thickness control during manufacturing.

Inventive Principle:
Principle #40Composite materials

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 effectively decreases thermal stress and improves heat radiation by absorbing thermal deformation and reducing thermal resistance, enhancing the reliability and efficiency of semiconductor devices without the need for thick joining layers or resin sealing.

Implementation Method 1

a plurality of spring-shaped nanostructures which are two-dimensionally arranged in the nano-structure layer

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

thermal stress due to a thermal deformation difference of each member by a temperature change

Methodology Applied
Scientific EffectThermal expansion: Thermal Expansion

Implementation Method 3

heat radiation by absorbing thermal deformation and reducing thermal resistance

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentEP2775511B1Semiconductor device
Publication Date: 2020.12.09 HITACHI LTD
  • EP2775511B1 patent drawingFigure 1(a)~1(b)
  • EP2775511B1 patent drawingFigure 2(a)~2(b)
  • EP2775511B1 patent drawingFigure 3(a)~3(e)

AI summary

A semiconductor device has a packaging structure in which a top surface of a semiconductor chip 1 is electrically connected to a conductive member 4 through a deformation absorption layer 2a and a joining layer 3a and a bottom surface thereof is electrically connected to a conductive member 5 through a deformation absorption layer 2b and a joining layer 3b. Each of the deformation absorption layers 2a and 2b includes a nano-structure layer 7 arranged at a center of a thickness direction and plate layers 6 and 8 of two layers with the nano-structure layer 7 therebetween. The nano-structure layer 7 has a structure in which a plurality of nano-structures 9 having a size of 1 µm or less are two-dimensionally arranged and thermal stress due to a thermal deformation difference of each member forming the semiconductor device is absorbed by deformation of the nano-structures 9.