Composite Stiffener Structure for Semiconductor Package Warpage

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Solution Overview

Problem

Semiconductor packaging faces challenges with warpage due to differences in coefficients of thermal expansion between substrates and semiconductor chips, which affects reliability and heat dissipation.

Innovation Solution

A semiconductor package design incorporating a stiffener with a body portion and a porous thermally conductive portion, where the body portion has a lower coefficient of thermal expansion and higher tensile strength, and the thermally conductive portion has a higher coefficient of thermal expansion and thermal conductivity, to compensate for thermal expansion differences and enhance heat dissipation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a stiffener with a single material is used, then the structural strength is sufficient, but the thermal expansion difference causes warpage

Engineering Contradiction:

Improvestiffener strengthVSAvoidwarpage control

Core Design Contradiction:

StrengthVSReliability

Solution Approach 1:

The stiffener is constructed as a composite structure with a body portion made of a first material and a porous portion made of a second material. The first material provides structural strength while the second material has a higher coefficient of thermal expansion to compensate for the difference between the substrate and semiconductor chip, thereby reducing warpage through the synergistic combination of materials with different thermal expansion properties.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

Different portions of the stiffener are assigned different materials with specific properties: the body portion uses a material optimized for strength, while the porous portion uses a material optimized for thermal expansion compensation. This local differentiation of material properties allows each region to fulfill its specific function while collectively solving the warpage problem.

Inventive Principle:

Principle #3Local quality

2Strength

If a dense solid structure is used, then the mechanical strength is high, but the thermal conductivity is insufficient for heat dissipation

Engineering Contradiction:

Improvestiffener strengthVSAvoidheat dissipation

Core Design Contradiction:

StrengthVSTemperature

Solution Approach 1:

The porous portion of the stiffener is constructed with a porous structure that provides enhanced thermal conductivity for heat dissipation while maintaining adequate mechanical strength. The porous structure allows for better thermal management by facilitating heat transfer, addressing the heat dissipation issue without completely sacrificing structural integrity.

Inventive Principle:

Principle #31Porous materials

3Reliability

If materials with matching thermal expansion coefficients are used, then warpage is reduced, but heat dissipation capability is compromised

Engineering Contradiction:

Improvewarpage controlVSAvoidheat dissipation

Core Design Contradiction:

ReliabilityVSTemperature

Solution Approach 1:

The composite stiffener structure combines materials with different thermal expansion coefficients, where the second material has a higher coefficient to compensate for warpage. Simultaneously, the porous structure of the second material provides enhanced thermal conductivity for heat dissipation, thus achieving both warpage control and improved thermal management through the synergistic composite design.

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

The design effectively controls warpage, improves heat dissipation, and increases the reliability of the semiconductor package by matching thermal expansion coefficients and optimizing material properties.

Implementation Method 1

a porous thermally conductive portion within the cavity... A thermal conductivity of the porous thermally conductive portion may be greater than a thermal conductivity of the body portion

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

The body portion may include a first material having a first coefficient of thermal expansion. The porous thermally conductive portion may include a second material having a second coefficient of thermal expansion, greater than the first coefficient of thermal expansion

Methodology Applied

Scientific EffectThermal expansion: Thermal Expansion

Data Source

PatentUS20250022811A1Semiconductor package

Publication Date: 2025.01.16 SAMSUNG ELECTRONICS CO LTD

AI summary

A semiconductor package includes a substrate including a first interconnection, an interposer disposed on the substrate, the interposer including a second interconnection electrically connected to the first interconnection, first and second semiconductor chips disposed on the interposer, the first and second semiconductor chips electrically connected to each other through the second interconnection, and a stiffener disposed on the substrate to be spaced apart from the interposer, the stiffener including a body portion having a cavity, and a porous thermally conductive portion within the cavity. The body portion includes a first material having a first coefficient of thermal expansion. The porous thermally conductive portion includes a second material having a second coefficient of thermal expansion, greater than the first coefficient of thermal expansion.