Fluxless Thermocompression Bonding With Plasma Oxide Removal

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Solution Overview

Problem

Existing thermocompression bonding processes face challenges in effectively removing both metal oxides and organic contaminants from electronic components and substrates, leading to performance degradation and increased costs due to the use of liquid flux and subsequent deflux processes, which are not suitable for removing organic contaminants and can generate new metal oxides.

Innovation Solution

A fluxless thermocompression bonding system utilizing a first and second plasma cleaning device within an inert gas environment to simultaneously remove organic contaminants and metal oxides from electronic components and substrates before bonding, preventing the formation of new metal oxides during the bonding process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If liquid flux is applied to remove metal oxides before bonding, then metal oxide removal is improved, but process cost increases and organic contaminants remain

Engineering Contradiction:

Improvemetal oxide removalVSAvoidprocess cost

Core Design Contradiction:

Object-affected harmful factorsVSEase of manufacture

Solution Approach 1:

The patent uses a plasma cleaning device that operates in an inert gas environment (nitrogen or argon atmosphere) to remove metal oxides from bonding surfaces. The inert atmosphere prevents re-oxidation during the bonding process, eliminating the need for liquid flux while maintaining effective oxide removal and reducing process costs.

Inventive Principle:

Principle #39Inert atmosphere (Inert environment)

Solution Approach 2:

The patent replaces the chemical mechanism of liquid flux with a plasma-based cleaning mechanism. The plasma cleaning device uses ionized gas to physically and chemically remove metal oxides through sputtering and oxidation reactions, substituting the liquid chemical application process with a controlled plasma environment.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Object-affected harmful factors

If flux and deflux processes are used, then metal oxide removal is improved, but bonding process cost increases significantly

Engineering Contradiction:

Improvemetal oxide removalVSAvoidbonding process cost

Core Design Contradiction:

Object-affected harmful factorsVSEase of manufacture

Solution Approach 1:

The patent extracts and eliminates the deflux process from the traditional bonding sequence by using plasma cleaning instead of liquid flux. This removal of the deflux step significantly reduces process complexity and cost, as the plasma cleaning leaves no residue requiring removal, thereby eliminating an entire process stage.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces expensive liquid flux materials with a plasma cleaning process that uses inert gas, which is consumed but leaves no residue. The plasma treatment is a one-time process that eliminates the need for costly flux materials and the additional deflux processing steps, reducing overall material and process costs.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

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 approach ensures a high-quality joint between electronic components and substrates by effectively removing impurities, reducing costs, and preventing performance degradation caused by residual impurities, thereby enhancing the reliability of the bonded package.

Implementation Method 1

a first plasma cleaning device operative to clean the electronic component and/or the base member by removing metal oxides therefrom

Methodology Applied

Scientific EffectPlasma cleaning: Plasma

Implementation Method 2

a second plasma cleaning device operative to clean the electronic component by removing organic contaminants therefrom

Methodology Applied

Scientific EffectPlasma cleaning: Plasma

Implementation Method 3

metal oxides will not form on the electronic component and base member after the second cleaning process and during the subsequent bonding process in the first container

Methodology Applied

Scientific EffectOxidation prevention: Oxidation

Data Source

PatentUS20240339430A1System and method for fluxless thermocompression bonding

Publication Date: 2024.10.10 ASMPT SINGAPORE PTE LTD

AI summary

A bonding system for bonding an electronic component to a base member includes a first container for forming a first inert environment where the base member is locatable during bonding of the electronic component. A first plasma cleaning device is located in the first container to clean the electronic component and/or the base member by removing metal oxides therefrom. A second plasma cleaning device is also provided to clean the electronic component by removing organic contaminants therefrom before the electronic component is conveyed into the first container. A bond head is movably installed in the first container to bond the electronic component to the base member after the electronic component and/or the base member have been cleaned by the first plasma cleaning device.