Charge-Induced Underfill Repulsion for Microelectronic Interconnect Reliability

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Solution Overview

Problem

The microelectronic industry faces challenges in packaging smaller devices due to filler particles from underfill materials getting trapped between interconnection structures and substrate bond lands, leading to reliability issues and reduced current carrying capacity.

Innovation Solution

Inducing a charge on the interconnection structures or filler particles to repel them away from the connection areas before attaching the microelectronic device to the substrate, using techniques such as x-ray radiation or electrical bias between plates, to create a 'filler free' region.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If underfill material is disposed between microelectronic device and substrate using standard techniques, then mechanical reinforcement is improved, but filler particles get trapped between interconnection structures and bond lands causing reliability issues

Engineering Contradiction:

Improvemechanical reinforcementVSAvoidconnection reliability

Core Design Contradiction:

StrengthVSReliability

Solution Approach 1:

The patent applies preliminary action by disposing the underfill material on the microelectronic device before the attachment process, and inducing a charge on the interconnection structures before filler particles can become trapped. This advance preparation prevents the harmful effect of filler entrapment during the subsequent attachment operation.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent replaces the purely mechanical underfilling process with an electrostatic-based approach. By inducing a charge on the interconnection structures, the system uses electrical forces to repel filler particles away from the bond lands, substituting mechanical placement with electrostatic control to prevent filler entrapment.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Ease of manufacture

If wafer level attachment techniques are used to dispose underfill material on active surface, then underfilling process is simplified, but filler particles still get trapped between interconnection structures and bond lands

Engineering Contradiction:

Improveunderfilling process easeVSAvoidconnection reliability

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The patent replaces the mechanical placement problem with an electrostatic solution. While maintaining the simplified wafer level attachment process, it introduces charge induction on interconnection structures to electrostatically repel filler particles, thereby preserving manufacturing ease while eliminating reliability issues.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The induced charge on the interconnection structures acts as an intermediary force field between the underfill material and the bond lands. This electrostatic intermediary repels filler particles away from the critical bonding area, allowing the underfill material to be disposed easily while preventing filler entrapment.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Volume of moving object

If interconnection structure pitch is reduced to achieve smaller devices, then device size is reduced, but filler particle entrapment becomes more likely

Engineering Contradiction:

Improvedevice sizeVSAvoidconnection reliability

Core Design Contradiction:

Volume of moving objectVSReliability

Solution Approach 1:

The patent replaces mechanical spacing requirements with electrostatic control. By using charge induction to repel filler particles, the system no longer depends on large pitch dimensions to prevent filler entrapment, enabling reduced interconnection structure pitch while maintaining reliability.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 method enhances the reliability of the connection by preventing filler particle entrapment, thereby improving the mechanical reinforcement and current carrying capacity of the microelectronic device-substrate interface.

Implementation Method 1

The underfill material is drawn between the microelectronic device and the microelectronic substrate by capillary action

Methodology Applied

Scientific EffectCapillary action: Capillary Action

Implementation Method 2

using techniques such as x-ray radiation or electrical bias between plates, to create a 'filler free' region

Methodology Applied

Scientific EffectX-ray radiation: X-Ray

Implementation Method 3

using techniques such as x-ray radiation or electrical bias between plates, to create a 'filler free' region

Methodology Applied

Scientific EffectElectrical bias: Electric Field

Data Source

PatentUS8999765B2Methods to prevent filler entrapment in microelectronic device to microelectronic substrate interconnection structures

Publication Date: 2015.04.07 INTEL CORP

AI summary

Embodiments of the present description include methods for attaching a microelectronic device to a microelectronic substrate with interconnection structures after disposing of an underfill material on the microelectronic device, wherein filler particles within the underfill material may be repelled away from the interconnection structures prior to connecting the microelectronic device to the microelectronic structure. These methods may include inducing a charge on the interconnection structures and may include placing the interconnection structures between opposing plates and producing a bias between the opposing plates after depositing the underfill material on the interconnection structures.