PCB Semiconductor Package Interconnect for CTE-Matched Reliability

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Solution Overview

Problem

Existing semiconductor package structures face challenges in achieving high reliability due to thermal expansion coefficient mismatches between components, leading to potential cracks and reduced joint reliability, as well as inefficient heat dissipation.

Innovation Solution

A semiconductor package structure with a connection structure having a coefficient of thermal expansion similar to the circuit board, featuring a central pad surrounded by inner and outer leads, and a semiconductor package with solder balls connecting the package substrate to the inner leads, allowing for reduced expansion differences and improved heat dissipation without direct contact between the package and the circuit board.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a direct connection structure is used between the semiconductor package and the circuit board, then the structural complexity is reduced, but the joint reliability deteriorates due to thermal expansion coefficient mismatches causing cracks

Engineering Contradiction:

Improvestructural complexityVSAvoidjoint reliability

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The patent introduces an intermediate connection structure consisting of a first connection structure with outer leads contacting the circuit board and inner leads contacting the package substrate, and a second connection structure with leads contacting both the first connection structure and the package substrate. This intermediary structure acts as a buffer to accommodate thermal expansion differences between the circuit board and package substrate, preventing cracks while maintaining electrical connectivity.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Temperature

If the semiconductor package is placed in direct contact with the circuit board, then the heat dissipation path is shortened, but the thermal expansion coefficient mismatch causes cracks and reduces reliability

Engineering Contradiction:

Improveheat dissipation efficiencyVSAvoidjoint reliability

Core Design Contradiction:

TemperatureVSReliability

Solution Approach 1:

The intermediate connection structures serve as thermal conduits while accommodating thermal expansion mismatches. The multi-layer connection architecture provides continuous thermal pathways from the package substrate through the connection structures to the circuit board, enabling effective heat dissipation without requiring direct contact that would cause cracking due to CTE differences.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Ease of manufacture

If a simplified single-layer connection structure is used, then the manufacturing process is simplified, but the ability to accommodate thermal expansion differences is reduced

Engineering Contradiction:

Improvemanufacturing process simplicityVSAvoidthermal expansion compatibility

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The connection structure is segmented into multiple functional layers: a first connection structure with outer leads for circuit board contact and inner leads for package contact, and a second connection structure with leads contacting both the first connection structure and the package substrate. This segmentation allows each layer to be optimized for specific functions (electrical connectivity, thermal management, mechanical compliance) while maintaining manufacturability through standardized assembly processes.

Inventive Principle:

Principle #1Segmentation

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 configuration enhances joint reliability by minimizing thermal expansion-induced cracks and facilitates effective heat dissipation from the semiconductor package, thereby improving the overall performance and reliability of the semiconductor module.

Implementation Method 1

A difference between thermal expansion coefficients of the connection structure and the circuit board may be less than a difference between thermal expansion coefficients of the circuit board and the first package substrate

Methodology Applied

Scientific EffectThermal expansion coefficient matching: Thermal Expansion

Implementation Method 2

The inner leads may be in contact with the solder balls

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentUS11848255B2Semiconductor package structure on a PCB and semiconductor module including the same

Publication Date: 2023.12.19 SAMSUNG ELECTRONICS CO LTD

AI summary

Disclosed are semiconductor package structure and semiconductor modules including the same. The semiconductor module includes a circuit board, a first semiconductor package over the circuit board, and a connection structure on the circuit board and connecting the circuit board and the first semiconductor package. The first semiconductor package includes a first package substrate. A difference in coefficient of thermal expansion between the connection structure and the circuit board may be less than a difference in coefficient of thermal expansion between the circuit board and the first package substrate.