Circuit Substrate Mounting Land Protrusions for Solder Void Reduction
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Solution Overview
Problem
In surface-mounting of electronic components on circuit substrates, the formation of solder voids due to vaporized flux gas leads to unsatisfactory joint strength and reliability issues, especially with large soldering areas, as existing techniques like using solder resist to divide electrode lands result in uneven solder distribution and reduced joint strength.
Innovation Solution
The use of a circuit substrate with a mounting land featuring protruding insulating portions that prevent division into multiple areas, allowing for even solder distribution and gas escape routes, thereby reducing solder voids and enhancing joint strength and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the mounting land is divided into multiple areas by solder resist, then gas escape routes are created and solder voids are reduced, but the amount of solder becomes uneven and joint strength decreases
Solution Approach 1:
The mounting land is divided into multiple areas by protruding portions of solder resist, creating gaps that serve as gas escape routes during soldering. This segmentation allows trapped gas to escape, reducing solder void formation while maintaining adequate solder distribution across the mounting land.
Solution Approach 2:
The protruding portions of solder resist are strategically positioned to create local gaps at specific areas of the mounting land. These localized gaps provide gas escape routes without significantly reducing the overall solder amount, ensuring that solder distribution remains relatively uniform and joint strength is maintained.
2Area of stationary object
If the soldering area is increased, then the electrical connection area is improved, but gas becomes trapped and solder voids increase
Solution Approach 1:
By dividing the large mounting land into multiple areas using protruding solder resist portions, the invention creates internal gas escape routes within the large soldering area. This allows the benefits of a large soldering area (improved electrical connection) to be maintained while preventing gas entrapment through the segmented structure.
Solution Approach 2:
The protruding portions of solder resist act as intermediary structures that facilitate gas escape from the interior of the large mounting land. These protrusions create gaps that serve as channels for gas to escape, mediating between the large soldering area and the external environment to prevent void formation.
3Object-affected harmful factors
If the mounting land is divided into multiple areas, then gas can escape more easily, but solder distribution becomes uneven
Solution Approach 1:
The protruding portions of solder resist are designed with specific dimensions and positioning to create localized gaps that are sufficient for gas escape but do not significantly disrupt overall solder distribution. The local modifications are optimized to maintain uniform solder flow while providing adequate gas escape paths.
Solution Approach 2:
The invention uses partial division of the mounting land rather than complete segmentation. The protruding portions create sufficient gaps for gas escape without excessively dividing the mounting land into small isolated areas, thereby maintaining relatively uniform solder distribution while achieving the gas escape function.
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 even solder distribution and reduces the formation of solder voids, resulting in improved mechanical and electrical connection reliability, even for components with large soldering areas, by providing a continuous mounting land area and gas escape paths.
Implementation Method 1
when solder is heated with a reflow furnace printed on a circuit substrate, a flux component contained in the solder vaporizes to generate gas in the solder
Implementation Method 2
After the melted solder flows into a space between the mounting land and the mounting terminal
Data Source
AI summary
A circuit substrate which is capable of decreasing the possibility that the amount of solder in the overall mounting land is uneven and reducing formation of a solder void even when a mounting terminal has a large soldering area. An electronic component having the mounting terminal is mounted on the circuit substrate. A mounting land is connected to the mounting terminal of the electronic component by soldering, and the mounting land has a protruding portion of an insulating material formed so as to protrude from an outer side of the mounting land toward an inner side of the mounting land, and the protruding portion does not divide the mounting land into a plurality of areas.