By MultPCB – Your Global PCB Manufacturing Partner
When it comes to PCB manufacturing, one of the most critical decisions—often overlooked by engineers and buyers—is choosing the right surface finish. The surface finish, also known as surface treatment, directly impacts solderability, shelf life, cost, and reliability of the PCB.
At MultPCB, we offer a wide range of surface finishes tailored to different applications, from prototype runs to mass production, consumer electronics to aerospace-grade builds.
Let’s break down the most common PCB surface treatments and help you understand which one fits your needs.
What is PCB Surface Finish?
A surface finish (also called surface treatment or coating) is applied to the exposed copper pads of a PCB to:
- Protect copper from oxidation
- Enable soldering during assembly
- Maintain long-term reliability
🛠️ Common PCB Surface Finishes Offered by MultPCB
✅ 1. HASL (Hot Air Solder Leveling)
| Feature | Details |
|---|---|
| Appearance | Uneven, glossy |
| Solderability | Good |
| RoHS Compliance | Only lead-free HASL |
| Best For | General, through-hole, and wave solder |
| Not Ideal For | BGA or fine-pitch |
✅ 2. ENIG (Electroless Nickel Immersion Gold)
| Feature | Details |
|---|---|
| Appearance | Smooth, flat, gold-colored |
| Solderability | Excellent |
| Shelf Life | 12+ months |
| Best For | Fine-pitch, BGA, and high-reliability |
| RoHS Compliance | Yes |
✅ 3. OSP (Organic Solderability Preservative)
| Feature | Details |
|---|---|
| Appearance | Matte copper |
| Solderability | Good (initial) |
| Shelf Life | 3–6 months |
| Best For | SMT, short-life products |
| Limitations | No multi-reflow |
✅ 4. Immersion Silver
| Feature | Details |
|---|---|
| Appearance | Silver-white, flat |
| Solderability | Excellent |
| Shelf Life | ~6–12 months |
| Best For | High-speed & RF circuits |
| Limitations | Sensitive to environment handling |
✅ 5. Immersion Tin
| Feature | Details |
|---|---|
| Appearance | Matte white |
| Solderability | Very good |
| Best For | Fine-pitch SMT |
| Limitations | Tin whiskers if not stored properly |
✅ 6. Hard Gold (Electrolytic Gold)
| Feature | Details |
|---|---|
| Appearance | Bright gold |
| Use Case | Edge connectors, wear-resistant pads |
| Not Ideal For | General soldering |
| Durability | Excellent mechanical wear resistance |
✅ 7. ENEPIG (Electroless Nickel Electroless Palladium Immersion Gold)
Also known as “universal finish” or “nickel-palladium-gold”
| Feature | Details |
|---|---|
| Appearance | Smooth, gold-colored |
| Layers | Nickel (barrier) + Palladium (anti-diffusion) + Gold (solderable) |
| Solderability | Excellent – works with soldering & wire bonding |
| Wire Bonding | Compatible with aluminum & gold wire |
| Shelf Life | >12 months |
| Cost | Higher than ENIG but more versatile |
| Best For | IC packaging, ENIG+BGA+wire bond compatibility, high-reliability PCBs |
| RoHS Compliance | Yes |
MultPCB Note: ENEPIG is often selected for advanced electronics, where BGA, fine-pitch soldering, and gold wire bonding must all work on the same board.
Choosing the Right Surface Finish – MultPCB Tips
| Application | Recommended Finish |
|---|---|
| Prototypes or low-cost production | HASL (lead-free) |
| BGA, fine-pitch, or HDI boards | ENIG or ENEPIG |
| High-speed digital or RF | Immersion Silver |
| Edge connectors or gold fingers | Hard Gold |
| Green manufacturing/short lifecycle | OSP |
| Complex PCBA + wire bonding | ENEPIG |
Still unsure? Our engineers at MultPCB can recommend the ideal finish based on your application and BOM.
Quality Control at MultPCB
All PCBs undergo strict surface finish validation:
- Visual & microscopic inspection
- Thickness verification (XRF)
- Solderability tests
- IPC Class 2 / Class 3 compliance as needed
Every PCB is only as reliable as its surface finish. At MultPCB, we provide the widest range of finishes, backed by experience, engineering support, and global delivery to ensure your product performs exactly as it should—from first prototype to mass production.
📩 Need help selecting the right finish?
Email: info@multpcb.com
🌐 Website: www.multpcb.com
