Surface Finish Guide
PCB surface finish guide for assembly and reliability.
Surface finish protects exposed copper and affects solderability, pad flatness, storage and assembly compatibility.
HASL, ENIG, OSP and immersion finishes
HASL and Lead Free HASL are common for many general PCB applications. ENIG provides a flat pad surface for fine pitch assembly. OSP is a simple organic copper protection option. Immersion Silver and related finishes may be reviewed when the application requires them.
How to choose a finish
Selection should consider component pitch, soldering method, storage requirements, pad flatness, product environment and compliance needs.
Finish review
Surface finish should be confirmed with assembly and reliability requirements.
| Finish | Typical advantage | Engineering note |
|---|---|---|
| HASL | Common solderable finish | Review pad flatness for fine pitch parts. |
| Lead Free HASL | Lead-free assembly compatibility | Common for compliant products. |
| ENIG | Flat surface and good solderability | Often used for fine pitch and gold contact needs. |
| OSP | Organic copper protection | Review storage and assembly timing. |
| Immersion Silver | Flat finish option | Confirm handling and product environment. |
Surface finish FAQ
What surface finishes are available?
HASL, Lead Free HASL, ENIG, OSP and Immersion Silver can be reviewed by PCB application requirements.
Which finish is suitable for fine pitch assembly?
ENIG is often selected when pad flatness and fine pitch assembly are important.
What materials are available?
FR-4, High Tg FR-4, Halogen Free, Metal Core and flexible materials can be reviewed with finish selection.
Related engineering pages
Review surface finish requirements with engineering.
Send assembly notes, pad requirements and product environment details.