What are the causes and effects of Solder Dewetting? How to prevent it?
Editorial Team - PCB Directory
May 2, 2023
Proper soldering techniques are essential to creating electronic devices that function properly. In the electronics industry when a PCB is manufactured, the immediate next step is to solder all the electrical components like resistors, capacitors, and many other components to the PCB traces. However, sometimes the process doesn’t go as planned and which eventually leads to soldering issues and poor electrical joints.
This is a comprehensive article that discusses the causes of Solder Dewetting, and problems that arise due to this phenomenon. The article also contains information on how you can prevent a Solder Dewetting situation by being cautious, and well-prepared.
A representation of a very basic solder dewetting
What is Solder Dewetting?
Solder dewetting is a surface phenomenon that occurs due to the reduction of surface energy between the solder and the substrate. It is a process where the solder material loses its wetting ability and adhesion to the underlying substrate.
In the context of printed circuit boards (PCBs), solder dewetting is a process where the solder material on the PCB surface loses its adhesion to the metal pad, resulting in the formation of small spherical balls or irregular-shaped regions of the bare copper surface.
During the dewetting process, the surface energy of the solder and the substrate material becomes imbalanced, leading to the formation of surface tension gradients that drive the solder to retract from the substrate surface. This results in the formation of isolated regions of the bare substrate surface, which can compromise the mechanical stability and electrical connectivity of the solder joint.
Causes of Solder Dewetting in PCBs
Solder Dewetting is a defect that can hinder the reliability and efficiency of a PCB. Here are some of the possible causes of the same:
There are several factors that can cause solder dewetting in PCBs. PCB assemblers should take appropriate steps to minimize these factors to ensure that high-quality solder joints are achieved.
Effects of Solder Dewetting on PCBs
The effects of solder dewetting on PCBs can be significant and detrimental to the performance and reliability of the circuit. Here are some of the effects:
In conclusion, solder dewetting is a critical issue that can significantly impact the reliability and performance of PCBs.
How to Prevent Solder Dewetting?
We have clearly seen the effects of Solder Dewetting and how harmful can it be for electronic devices and electrical components connected to a PCB. Let’s have a look at some of the ways we can prevent Solder Dewetting:
The image shows a clear distinction between a proper and improper soldering
In conclusion, solder dewetting is a surface phenomenon that occurs due to the reduction of surface energy between the solder and the substrate, which can cause significant damage to the reliability and performance of printed circuit boards (PCBs). Contamination, oxidation, solderability issues, and poor design practices are some of the possible causes of solder dewetting in PCBs. The effects of solder dewetting can lead to reduced electrical conductivity, increased mechanical stress, decreased reliability, poor thermal performance, and difficulty in repair.
To prevent solder dewetting, PCB designers should ensure proper design practices, while PCB assemblers should take appropriate steps to minimize factors that lead to contamination, oxidation, and solderability issues. Proper cleaning and handling of solder paste, and the proper storage of PCBs can also prevent solder dewetting. Ultimately, proper soldering techniques and precautions are crucial to ensure high-quality and reliable solder joints in electronic devices.
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