Solder Bump Reflow Chamber Cover for Flux-Free Oxide Reduction

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Solution Overview

Problem

The process of forming solder bumps using solder paste with flux requires subsequent washing to remove flux residue and oxide film reduction, which can lead to adhesion of evaporated substances on the substrate, increasing processing time and complexity.

Innovation Solution

A soldered product manufacturing device and method that utilize a cover to minimize substrate contact with evaporated substances, supply reducing gas like formic acid to react with oxide films quickly, and control heat radiation, allowing for efficient oxide reduction without flux, thus eliminating the need for washing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If formic acid is used to reduce oxide film instead of flux, then washing process can be eliminated, but evaporated substances adhere to the substrate

Engineering Contradiction:
Improveprocess simplificationVSAvoidadhesion of evaporated substances
Core Design Contradiction:
Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

A cover is introduced as an intermediary component between the heating zone and the substrate. This cover prevents evaporated substances from directly contacting and adhering to the substrate, while still allowing the formic acid reduction process to proceed effectively on the oxide film.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The harmful effect of evaporated substance adhesion is extracted and isolated from the substrate by introducing a cover. This separates the substrate from the harmful evaporated substances while maintaining the beneficial oxide reduction effect of formic acid.

Inventive Principle:
Principle #2Taking out (Extraction)

2Speed

If heating temperature is increased to accelerate oxide reduction, then reduction speed increases, but more substances evaporate and adhere to substrate

Engineering Contradiction:
Improveoxide reduction speedVSAvoidevaporated substance adhesion
Core Design Contradiction:
SpeedVSObject-affected harmful factors

Solution Approach 1:

The cover acts as a protective intermediary that allows high-temperature heating to proceed at full speed for accelerated oxide reduction, while simultaneously blocking the harmful evaporated substances from reaching and adhering to the substrate.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If processing time is extended to ensure complete oxide reduction, then reduction completeness improves, but productivity decreases

Engineering Contradiction:
Improveoxide reduction completenessVSAvoidmanufacturing speed
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The cover enables the system to maintain high processing speeds without compromising oxide reduction completeness. By protecting the substrate from evaporated substances, the cover allows faster processing times while still achieving thorough oxide film reduction.

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

This approach enhances the speed of oxide reduction, suppresses adhesion of unnecessary substances to the substrate, and simplifies the manufacturing process by eliminating the need for flux washing, improving productivity.

Implementation Method 1

a reduction process in which hydrogen gas at the temperature of the melting point or higher of solder is blown to the soldering part for a short time and of a process in which the solder is heated and melted in the atmosphere of hydrogen after the hydrogen gas has been blown. When the hydrogen gas at the melting point or higher of the solder is blown to the soldering part for a short time, an oxide film on the surface of the soldering part is reduced and removed.

Methodology Applied
Scientific EffectOxide reduction: Reduction

Implementation Method 2

a heating portion configured to heat the substrate placed on the stage

Methodology Applied
Scientific EffectHeating: Heating

Implementation Method 3

heating and melting the mixture to form solder bumps

Methodology Applied
Scientific EffectMelting: Melting

Implementation Method 4

components of the solder and/or the substrate and/or the formic acid are occasionally evaporated when the solder and the substrate are heated

Methodology Applied
Scientific EffectEvaporation: Evaporation

Implementation Method 5

the evaporated components (substances) are diffused and deposited on the inner walls and the like of a chamber

Methodology Applied
Scientific EffectCondensation: Condensation

Data Source

PatentEP4006959B1Solder-attached product manufacturing device, and solder-attached product manufacturing method
Publication Date: 2023.11.01 ORIGIN CO LTD(JP)
  • EP4006959B1 patent drawingFigure 1
  • EP4006959B1 patent drawingFigure 2
  • EP4006959B1 patent drawingFigure 3

AI summary

A solder-attached product manufacturing device 1 is provided with: a stage 13 on which a substrate W having an array of solder is placed; a cover 16 which covers at least an upper portion of the substrate W placed on the stage 13 with a predetermined distance therebetween; a chamber 11 in which the stage 13 and the cover 16 are accommodated; a heating unit 15 which heats the substrate W on the stage 13; and a reducing gas supply device 19 which supplies a reducing gas F. A solder-attached product manufacturing method comprises: placing a substrate W on a stage 13 using the solder-attached product manufacturing device 1; covering the substrate W placed on the stage 13 with a cover 16; heating the substrate W; and supplying a reducing gas F into a chamber 11.