Tin Plating Problems

Tin plating is an essential process in making semiconductors that can present many common problems.

While semiconductor manufacturers and other engineers who conduct tin plating may encounter a variety of problems, most of them are due to the same small handful of causes. The vast majority of problems encountered with tin plating are due to an insufficient amount of some ingredient or element, improper cleaning and filtering or excessive power.

Unwanted Formations

Dendrites form due to insufficient additives, brightener, replenishment chemicals or acid (sulfuric acid). Nodules form in the presence of solids in the bath to filter out. Brittle deposits develop from organic contamination, which carbon treatment remedies.

Abnormalities

Graininess and pitting result from insufficient metal (stannous sulfate) or additive chemical replenishment. Blistering indicates poor or inadequate cleaning.

Power Issues

Burning and anode polarization results from too high a plating current. Gassing indicates either the plating current or voltage is too high. Fix reduced throwing power by adding more acid, metal or additive chemical replenishment.

References

• siliconfareast.com: Lead Finish Guides - Page 1 of 2 - Tin Plating Troubleshooting
• Finishing.com: Tin Plating Problems