Underfill Confinement Structure for Signal-Safe Chip Packaging

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Solution Overview

Problem

Existing underfill processes result in uncontrollable areas of the underfill layer, leading to material waste and issues like capacitance/inductance/electromagnetic interference due to the free-flowing nature of the underfill layer on the substrate.

Innovation Solution

Incorporating a protective structure adjacent to the underfill layer to define a confinement region, limiting the area and shape of the underfill layer, thereby controlling its amount and consistency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the underfill layer is applied using jetting or dispensing process to cover pads and solder balls, then the bonding between electronic element and substrate is improved, but the area of the underfill layer cannot be controlled, resulting in material waste and electromagnetic interference

Engineering Contradiction:

Improvebonding reliabilityVSAvoidunderfill material waste

Core Design Contradiction:

ReliabilityVSLoss of substance

Solution Approach 1:

The patent applies a preliminary action by forming a hydrophobic protective structure on the substrate before applying the underfill layer. This protective structure pre-defines the confinement region where the underfill layer will be contained, preventing uncontrolled spreading and material waste while ensuring proper coverage of pads and solder balls for reliable bonding

Inventive Principle:

Principle #10Preliminary action

2Reliability

Engineering Contradiction:

Improvebonding reliabilityVSAvoidelectromagnetic interference

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The hydrophobic protective structure is formed in advance to establish clear boundaries for the underfill layer. This preliminary confinement structure prevents the underfill material from spreading beyond the intended area, thereby eliminating uncontrolled capacitance and inductance effects that would interfere with signal integrity

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent applies local quality by creating a hydrophobic region with distinct properties compared to the surrounding hydrophilic substrate. This local differentiation in surface properties ensures that the underfill layer remains confined to specific areas where it is needed for bonding, while preventing electromagnetic interference in other regions

Inventive Principle:

Principle #3Local quality

3Ease of manufacture

If the underfill layer is allowed to flow freely on the substrate, then the underfill process is simple, but the area and shape of the underfill layer are inconsistent, leading to quality control issues

Engineering Contradiction:

Improveunderfill process simplicityVSAvoidunderfill layer area consistency

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The hydrophobic protective structure serves as an intermediary element between the substrate and the underfill layer. It mediates the interaction by providing a clear boundary that guides the underfill material flow, ensuring consistent area and shape without complicating the overall underfill process or requiring complex dispensing control systems

Inventive Principle:

Principle #24Intermediary (Mediator)

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 protective structure effectively controls the area of the underfill layer, ensuring consistent material usage and reducing signal loss and interference in high-frequency applications.

Implementation Method 1

an underfill process is performed, so as to allow an underfill layer to enter the gap between the electronic element and the substrate via the siphon phenomenon

Methodology Applied

Scientific EffectCapillary action: Capillary Action

Data Source

PatentUS12610842B2Electronic device including an underfill layer and a protective structure adjacent to the underfill layer

Publication Date: 2026.04.21 INNOLUX CORP

AI summary

The disclosure provides an electronic device and a manufacturing method thereof. The electronic device includes a substrate, an electronic element, an underfill layer, and a protective structure. The electronic element is disposed on the substrate. At least a portion of the underfill layer is disposed between the substrate and the electronic element. A thickness of the underfill layer is not greater than a height from a surface of the substrate to an upper surface of the electronic element. The protective structure is disposed on the substrate and adjacent to the underfill layer. The electronic device and the manufacturing method thereof of the disclosure may effectively control an area of the underfill layer.