Segmented Lid Structure for PoP Warpage and Underfill Delamination

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Solution Overview

Problem

Existing semiconductor package structures face challenges with thermal expansion mismatch and warpage issues due to mismatched coefficients of thermal expansion (CTE) among different elements, which can lead to underfill delamination and reliability problems in Package-on-Package (PoP) technology.

Innovation Solution

A lid structure with multiple separate sections is designed to cover integrated circuit dies and expose the underfill, addressing the CTE mismatch by providing a buffer and reducing warpage, while also protecting electronic components.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If a traditional solid lid structure is used to cover integrated circuit dies, then component protection is improved, but thermal expansion mismatch causes warpage and underfill delamination

Engineering Contradiction:

Improveprotection of integrated circuit diesVSAvoidunderfill delamination and warpage

Core Design Contradiction:

Object-affected harmful factorsVSReliability

Solution Approach 1:

The lid structure is divided into multiple separate sections instead of a single solid piece. Each section can independently accommodate thermal expansion and contraction, reducing stress on the underfill and preventing delamination while still protecting the integrated circuit dies.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the lid structure have different properties - the lid sections provide protection and thermal management where needed, while gaps between sections allow for thermal expansion accommodation. This localized differentiation resolves the contradiction between protection and thermal stress management.

Inventive Principle:

Principle #3Local quality

2Adaptability or versatility

If materials with different coefficients of thermal expansion are used in PoP structure, then functional integration is improved, but thermal mismatch causes stress and reliability issues

Engineering Contradiction:

Improvefunctional integration of PoP deviceVSAvoidstructural stability under thermal stress

Core Design Contradiction:

Adaptability or versatilityVSStability of the object's composition

Solution Approach 1:

The lid is segmented into multiple sections that can independently respond to thermal expansion and contraction. This segmentation allows the structure to accommodate the thermal mismatch between different materials (substrate, underfill, lid) while maintaining overall structural stability and functional integration.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The gaps between lid sections act as intermediaries that absorb thermal stress. These gaps provide a buffer zone that mediates the thermal expansion differences between materials with mismatched CTE values, preventing stress concentration and maintaining structural stability.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Ease of manufacture

If a continuous lid structure is used, then manufacturing simplicity is improved, but warpage control and delamination prevention become difficult

Engineering Contradiction:

Improvelid structure fabricationVSAvoidwarpage control and alignment

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

Rather than attempting to manufacture a large continuous lid with precise warpage control, the lid is divided into smaller sections that are easier to manufacture with tight tolerances. Each section can be independently fabricated and assembled, improving manufacturing precision while reducing overall warpage issues.

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

The solution effectively reduces underfill delamination and enhances the reliability of the package structure by managing thermal expansion and protecting components, thereby improving the structural integrity and performance of PoP devices.

Implementation Method 1

the coefficients of thermal expansion (CTE) are mismatched among different elements

Methodology Applied

Scientific EffectThermal expansion: Thermal Expansion

Data Source

PatentUS12183714B2Package structures and method for forming the same

Publication Date: 2024.12.31 TAIWAN SEMICONDUCTOR MANUFACTURING CO LTD

AI summary

A package structure is provided. The package structure includes a first package component, a second package component, and a lid structure. The first package component includes a plurality of integrated circuit dies and an underfill formed between the integrated circuit dies. The second package component includes a substrate, and the first package component is mounted on the substrate. The lid structure is disposed on the second package component and around the first package component, and the lid structure covers the integrated circuit dies and exposes the underfill.