Views: 18 Author: Site Editor Publish Time: 2023-06-07 Origin: Site
The overall functionality of a PCB board depends upon the conductivity of copper tracks. These tracks tend to oxidize when exposed to the atmosphere, and creates problems when soldering during component placement. OSP or Organic Solderability Preservative does two things: temporarily protect exposed copper from being oxidized and improves solderability before component fixation (assembly).
OSP creates a very thin (100-4000 Angstroms) organic coating on the PCB board, which is a water-based chemical compound of ‘Azole family’ such as benzotriazoles, imidazoles, and benzimidazoles. This compound gets absorbed by the exposed copper and generates a protected film to prevent oxidization.
HASL (Hot Air Solder Leveling) is a metallic surface finishing technique, which is performed on the outermost layer of the PCB board to protect the exposed copper surfaces like tracks until the component placement and soldering is completed.
The HASL coating is composed of Solder with 63% Tin and 37% Lead, and during the assembly process, this coating gets dissolved with the soldering material.