Molding Underfill for Semiconductor Package Reinforcement

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Solution Overview

Problem

Semiconductor packages, such as quad flat pack, pin grid array, ball grid array, flip chips, 3D ICs, wafer level packages, and package on package devices, are vulnerable to stresses and strains that can degrade electrical connections, leading to potential failures in connectivity and reliability.

Innovation Solution

The implementation of a molding underfill (MUF) between the package component and the device, which encapsulates electrical connections and provides reinforcement support against stress and strain, using materials like epoxy, deformable gel, or thermal plastic polymer, extending along the package component's sides to varying heights to minimize damage from thermal fluctuations and physical manipulation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If molding underfill is applied to encapsulate electrical connections, then reliability and durability of electrical connections are enhanced, but device complexity and manufacturing process steps increase

Engineering Contradiction:

Improvereliability of electrical connectionsVSAvoidcomplexity of packaging structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The molding underfill acts as an intermediary material between the package component and the device, providing mechanical reinforcement and stress distribution to the electrical connections (solder balls, bumps, or wire bonds) without requiring fundamental changes to the existing packaging architecture

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent utilizes changes in the physical parameters of the underfill material, specifically its viscosity, to enable self-leveling and automatic filling of gaps between electrical connections during the molding process, eliminating the need for additional alignment or filling steps

Inventive Principle:

Principle #35Parameter changes

2Strength

If molding underfill is used to provide reinforcement support, then resistance to stress and strain increases, but manufacturing time and process steps increase

Engineering Contradiction:

Improveresistance to stress and strainVSAvoidmanufacturing time

Core Design Contradiction:

StrengthVSLoss of time

Solution Approach 1:

The patent combines the underfill application step with the existing molding compound encapsulation process, where the underfill is applied and cured simultaneously with or before the molding compound is applied, thereby integrating reinforcement into the standard packaging workflow without adding significant time

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The underfill is applied in advance of final device assembly and testing, allowing early reinforcement of electrical connections before they are subjected to stress during subsequent manufacturing and usage phases

Inventive Principle:

Principle #10Preliminary action

3Object-affected harmful factors

If molding underfill encapsulates electrical connections, then protection against breaking and cracking is improved, but material cost and processing complexity increase

Engineering Contradiction:

Improveprotection against breaking and crackingVSAvoidcomplexity of material application

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The molding underfill serves as a protective intermediary layer that distributes mechanical stresses away from vulnerable electrical connections, preventing breaking and cracking without requiring complex protective structures or additional shielding components

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The underfill material provides homogeneous encapsulation around electrical connections, creating uniform stress distribution and protection against various failure modes including breaking, cracking, and shearing across different connection types

Inventive Principle:

Principle #33Homogeneity

Data Source

PatentUS9287143B2Apparatus for package reinforcement using molding underfill

Publication Date: 2016.03.15 TAIWAN SEMICONDUCTOR MANUFACTURING CO LTD

AI summary

A method and apparatus for a reinforced package are provided. A package component may be electrically coupled to a device through a plurality of electrical connections. A molding underfill may be interposed between the package component and the device and may encapsulate the plurality of electrical connections or a subset of the plurality of electrical connections between the package component and the device. The package component may also include a molding compound. The plurality of the electrical connections may extend through the molding compound with the molding underfill interposed between the molding compound and the device to encapsulate the plurality of electrical connections or a subset of the plurality of electrical connections between the package component and the device. The molding underfill may extend up one or more sides of the package component.