A UV melamine backup board is an HDF core with a UV-cured melamine surface that seals out moisture, the main cause of exit-burr drift in humid plants, and adds a harder (75-80 HD) face. It is the popular choice for 6-24 layer multilayer and 1-2 step HDI, bridging economical HDF and premium phenolic.
Key Takeaways
- UV-cured melamine face seals the board against moisture — stable in humid seasons and climates.
- Three grades: UV Melamine 840 (75 HD, moisture-sealed), UV Melamine 880 (80 HD, HDI & back-drill main grade) and UV Melamine 950 (80 HD, high-density microvia grade).
- Lower smear than bare HDF on 6–24 layer boards — cleaner hole walls, better plating quality.
What Is a UV Melamine Backup Board?
A UV melamine backup board is an HDF core with a UV-cured melamine-resin surface layer. The sealed face prevents moisture absorption — the leading cause of exit burr drift in humid factories — while the harder surface (75–80 HD) reduces resin smear on the hole wall.
This is the most popular backup board category for 6–24 layer multilayer PCB and 1–2 step HDI microvia drilling, bridging the gap between economical HDF and premium phenolic. For applications requiring an elastic core — such as FPC and rigid-flex — YUESHAN also offers Melamine Laminate Backup, a hot-pressed melamine paper laminate with a wood-fibre core.
Grade Options: UV Melamine 840 · 880 · 950
UV Melamine 840 — Moisture-Sealed Surface
80±5 HD · for humid lines & FPC
| Property | Spec |
|---|---|
| Base | 840 HDF |
| Surface | Melamine face, UV-sealed |
| Hardness | 80±5 HD |
| Thickness | 2.0 / 2.5 mm |
- Melamine face sealed against moisture — stable exit burr across humid seasons.
- Lower smear than bare HDF on 6–16 layer boards.
- Good drill-life balance for flex-rigid and FPC runs.
UV Melamine 880 — HDI & Back-Drill Main Grade
80±3 HD · UV melamine face · for 12–24 L & HDI
| Property | Spec |
|---|---|
| Base | 880 HDF |
| Surface | UV-cured melamine, coated |
| Hardness | 80±3 HD |
| Thickness | 2.0 / 2.5 mm |
| Density | 880±30 kg/m³ |
- Default grade for HDI microvia and multilayer 6–24 L.
- UV-cured melamine face — low smear, high location accuracy.
- Pairs with thermoset-coated aluminum and back-drill sheets.
UV Melamine 950 — HDI Microvia Grade
83±3 HD · 950 HDF core · dense HDI panels & tighter tolerances
| Property | Spec |
|---|---|
| Base | 950 HDF |
| Surface | UV-cured melamine, coated |
| Hardness | 83±3 HD |
| Density | 980±30 kg/m³ |
| Thickness | 2.5 mm |
| Flatness | ≤0.10 mm |
| Exit burr | ≤0.05 mm (typical) |
- Highest-density UV melamine grade (950 kg/m³) — resists compression better than 880 for tight-tolerance HDI microvia.
- UV-cured melamine coating prevents humidity absorption during storage.
- Ultra-low smear for sub-Ø0.15 mm vias on 1–2 step HDI.
- Pairs with coated lubricant aluminum for best microvia accuracy.
Sizes & Packaging
| Size (mm) | Thickness | Sheets / pallet | MOQ |
|---|---|---|---|
| 940 × 1245 | 2.5 mm | 300 | 100 sheets |
| 520 × 620 | 2.5 mm | 800 | 200 sheets |
Sizes & Packaging
| Size (mm) | Thickness | Sheets / pallet | MOQ |
|---|---|---|---|
| 940 × 1245 | 2.0 / 2.5 mm | 300 | 100 sheets |
| 520 × 620 | 2.0 / 2.5 mm | 800 | 200 sheets |
Technical Highlights
- UV-cured melamine barrier — prevents moisture ingress that causes burr drift in humid climates (Southeast Asia, India, coastal factories).
- Low smear — the melamine face reduces resin transfer to the hole wall, improving plating adhesion and reducing desmear load.
- Harder surface than HDF — 75–80 HD vs 70 HD means better location accuracy and cleaner hole exits.
- Three grades to choose from — UV Melamine 840 for moisture-sealed standard drilling, UV Melamine 880 for HDI & back-drill, and UV Melamine 950 for tight-tolerance microvia.
- Pair with coated entry — UV melamine reaches its full potential when paired with lubricant aluminum for HDI lines.
Melamine vs HDF vs Phenolic
| Factor | UV Melamine | HDF | Phenolic PHE |
|---|---|---|---|
| Hardness | 75–80 HD | 70 HD | 90±5 HD |
| Moisture resistance | Sealed surface | Standard | Waterproof |
| Smear level | Low | Moderate | Very low |
| Best layer range | 6–24 L | 2–12 L | HDI / IC substrate |
| Cost | Medium | Low | Premium |
For standard 2–12 layer boards with cost priority, use HDF. For IC substrate below Ø0.10 mm, use Phenolic PHE. For FPC and rigid-flex applications requiring an elastic core, see Melamine Laminate Backup. For a full breakdown of all grades, see the backup board selection guide.
Applications
Microvia 1–2 step
UV Melamine 880 with coated aluminum entry for sub-Ø0.15 mm vias.
See HDI Solution →6–24 L standard boards
UV Melamine 840 for reliable drilling in all climates.
See 5G / Server →Controlled-depth stub
Melamine 880 paired with back-drill aluminum for 5G lines.
See Back-drill Alu →Flexible PCB drilling
Thin 2.0 mm Melamine 840 with 0.15 mm entry for flex lines.
See Medical →Recommended Pairing
FAQ
What is a UV melamine backup board?
A UV melamine backup board is an HDF core with a UV-cured melamine-resin surface that seals against moisture and provides a harder (75–80 HD) drilling surface than standard HDF.
What's the difference between Melamine 840 and 880?
Melamine 840 (75 HD) is moisture-sealed for 6–16 layer boards and humid environments. Melamine 880 (80 HD) is harder with UV-cured face, designed for HDI microvia and 12–24 layer boards with tighter accuracy requirements.
Can UV melamine be used in humid factories?
Yes — the UV-cured melamine face is specifically designed to prevent moisture absorption that causes exit burr in humid conditions. This makes it the preferred choice for factories in Southeast Asia, India and coastal regions.
How does it compare to HDF on smear?
UV melamine produces significantly less resin smear than bare HDF, resulting in cleaner hole walls and better plating quality. This is especially important for high-layer-count boards where smear removal is difficult.
Can I get a free sample?
Yes — free samples and full TDS/MSDS are shipped worldwide within 5–7 days. Contact Mr. Lucky Xu to request a side-by-side comparison.