Airflow Control Cover for Vapor Reflow Solder Ball Alignment
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Solution Overview
Problem
The vapor phase soldering method often results in solder ball mounting defects due to misalignment caused by airflow or heat transfer fluid movement during the reflow process, especially with smaller solder balls on printed circuit boards.
Innovation Solution
A solder reflow apparatus with an airflow control cover featuring vapor passage holes is used to direct heated heat transfer fluid towards the solder balls, generating a drag force that fixes their position without direct contact, preventing misalignment during the reflow process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If vapor phase soldering method is used to reflow solder balls, then soldering can be performed, but airflow or heat transfer fluid movement may move the solder balls causing mounting defects
Solution Approach 1:
A support structure with support holes is introduced as an intermediary between the heat transfer fluid and the solder balls. The support structure allows controlled flow of heat transfer fluid through its support holes while physically restraining the solder balls, preventing them from being moved by uncontrolled airflow during the vapor phase soldering process.
Solution Approach 2:
The patent utilizes controlled fluid flow through the support structure to achieve both heating and positioning functions. The support structure is designed to allow heat transfer fluid to pass through while maintaining precise control over the fluid flow path, ensuring solder balls remain stationary during the soldering process.
2Temperature
If heat transfer fluid is supplied to solder balls during reflow, then soldering is enabled, but solder balls may be displaced by the fluid flow
Solution Approach 1:
The support structure acts as a mediator that separates the thermal function from the positioning function. It allows heat transfer fluid to pass through support holes for heating while simultaneously serving as a physical barrier that prevents solder ball displacement, thus enabling temperature control without compromising alignment precision.
Solution Approach 2:
The support structure provides localized support at specific support holes positioned around the solder balls. This localized approach allows heat transfer fluid to be supplied precisely where needed for heating while maintaining solder ball position control only in the critical areas where balls are placed.
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 solution effectively prevents solder ball mounting defects by maintaining the position of solder balls during reflow, ensuring accurate alignment and reliable soldering in the vapor phase soldering method.
Implementation Method 1
soldering the solder members by supplying the heat transfer fluid in the vapor state to surfaces of the solder members through the plurality of the vapor passage holes
Implementation Method 2
generating a drag force that fixes their position without direct contact
Data Source
AI summary
In a method of manufacturing an electronic device, a substrate including a plurality of bonding pads on a first surface thereof is provided. Solder members are attached on the plurality of bonding pads respectively. An airflow control cover is positioned on the first surface of the substrate above the solder members, the airflow control cover including a plurality of vapor passage holes that allows air to flow toward the solder members. The substrate on which the airflow control cover is positioned is loaded into a vapor generating chamber that accommodates a heat transfer fluid therein. The heat transfer fluid is heated to place the heat transfer fluid in a vapor state within the chamber. The solder members are soldered by supplying the heat transfer fluid in the vapor state to surfaces of the solder members through the vapor passage holes of the airflow control cover.