If your business involves the manufacturing of electronic products, you probably understand the value of electroplating in the production process. Electroplating can serve many different purposes. For instance, copper plating can increase the ability of semiconductors and circuits to conduct electricity, and gold plating is often used to provide low and stable contact resistance, make the part less susceptible to corrosion, and increase aesthetics.
An important factor in the success of any electronic component plating or other metal finishing process is proper surface preparation. The presence of ionic residue can hinder the ability of the component to conduct electricity and prevent the finished product from performing at maximum efficiency.
The Evolution of Surface Preparation Procedures
For years, the traditional method of cleaning and removing both ionic and non-ionic residues had been to apply an organic solvent. However, environmental considerations gradually led to a shift in focus. Many individuals were concerned that the chemicals found in these solvents were contributing to the depletion of the ozone layer. The industry attempted to combat this issue by developing “no clean” fluxes in the early 1990s. Another innovation was the water-soluble flux that could be cleaned with water instead of chemicals.
As cleaning, performance and environmental standards continued to evolve — along with the demand for more dependable long-term performance in high quality electronic products — acceptable surface preparation procedures have changed accordingly. Upgrades in solders and various electronic assemblies have now made appropriate surface cleaning and preparation more essential than ever.
One example is the requirement that solders are free of lead. Lead-free solders make ionic flux residue more adherent and more difficult to remove. The common practice is to use high-pressure hot-water systems to remove residue.
Removing Ionic and Non-Ionic Residue
The prevailing conventional wisdom these days is that the surface preparation process should focus on the removal of non-ionic and ionic residue. The problem is that current electronic industry testing standards are designed to detect the presence of only ionic residue. This can have undesirable consequences from an electroplating perspective. After all, failure to remove non-ionic contaminants can prevent uniform adhesion of the metal coating.
There’s also the mistaken belief that plating actually prevents the need for cleaning. In reality, the opposite is true. The failure to remove contaminants prior to coating application can actually result in residue becoming trapped, which creates areas where adhesion doesn’t occur. This can significantly limit electroplating effectiveness and lead to premature part or component failure.
Contact Sharretts Plating Company to learn more about the relationship between electronic component surface preparation and the electroplating process.