How Drill Bit Coating Technology Enables Stable Mass Production of Advanced PCBs
As AI server computing power surges, PCB (Printed Circuit Board) manufacturing is facing new challenges. Long regarded as a “mature” technology, PCB production now demands higher precision, especially in microvia drilling. In this environment, coated drill bits have become a critical enabler for stable, high-yield production of high-density PCBs (HDI PCBs).
At SIMVACO, we combine advanced coating technology, process control, and equipment capability to help PCB manufacturers meet the demands of next-generation AI servers.
1. AI Servers Are Driving Higher PCB Requirements
Modern AI servers impose stringent requirements on PCBs:
- High-speed signals: Differential rates moving from 56 Gb/s to 112 Gb/s and beyond, requiring impedance control within ±5 %.
- Multi-layer complexity: 20–30+ layers with build-up structures are now standard.
- Microvias: φ0.10–0.25 mm vias are widely used in HDI boards.
- Thermal & power density: High-density devices require advanced thermal management, signal integrity (SI), and electromagnetic compatibility (EMC).
These factors make via drilling quality, via wall plating, and copper uniformity the most critical indicators of PCB performance.
2. Why Drill Stability Becomes a Bottleneck
High-speed, high-density PCBs create specific challenges:
- High aspect ratios: Microvias φ0.10–0.20 mm can reach aspect ratios of 6–8:1. Conventional drills struggle to maintain stability.
- Composite wear: High-fiberglass boards accelerate wear and cause resin adhesion, leading to heat buildup.
- High-speed spindle operation: PCB drills often run at 150,000–300,000 RPM, increasing thermal stress.
The tip condition and consistency of the drill bit directly influence via quality and production yield.
3. Why Coated Drill Bits Are Essential
Uncoated carbide drills face:
- Rapid wear and reduced life
- Rough via walls
- Higher risk of breakage and misalignment
- Microstructural defects after plating
Coated drill bits are no longer optional—they are a must for stable, consistent HDI PCB production. Choosing the right coating technology for your PCB conditions is critical.
4. Comparing Drill Bit Coating Technologies
PVD Nitride Coatings (TiN / TiAlN / AlTiN)
| Feature | Value / Benefit |
|---|---|
| Thickness | 0.4–1.2 μm |
| Hardness (HV) | 2300–3200 |
| Friction | 0.30–0.45 |
| Suitable via | ≥0.25 mm |
Best for: Medium-diameter vias and thick boards
Pros: High wear resistance, mature process
Cons: Higher friction → heat in microvias, limited resin adhesion suppression
DLC (Diamond-Like Carbon) Coatings
| Feature | Value / Benefit |
|---|---|
| Thickness | 0.2–0.8 μm |
| Hardness (HV) | 2500–4000 |
| Friction | 0.05–0.15 |
| Suitable via | ≤0.25 mm |
Best for: High-density HDI boards, φ0.10–0.20 mm microvias
Pros: Ultra-low friction, prevents resin adhesion, reduces heat
Cons: Requires precise equipment and process control
TAC / TiAlC Carbon-Doped Coatings
| Feature | Value / Benefit |
|---|---|
| Thickness | 0.3–0.9 μm |
| Hardness (HV) | 2800–3500 |
| Friction | 0.20–0.35 |
| Suitable via | 0.15–0.35 mm |
Best for: Medium-diameter vias, high-fiberglass materials, high-volume production
Pros: Balanced hardness and friction, better process control, tolerant of internal stress
Key Comparison
| Coating | Hardness | Friction | Microvia Suitability | Process Control | Suitable Diameter |
|---|---|---|---|---|---|
| PVD Nitride | High | Medium | ⚠️ | High | ≥0.25 mm |
| DLC | High | Ultra-low | ✅ | Medium–Difficult | ≤0.25 mm |
| TAC/TiAlC | High | Low–Medium | ⚠️ | High | 0.15–0.35 mm |
5. Process Controllability Matters More Than Material
- Coating thickness precision: Microvia drill tips are extremely thin; ±0.1 μm variation changes cutting mechanics.
- Internal stress: High-stress coatings can crack at high speeds.
- Batch consistency: Single excellent drills do not guarantee stable mass production.
At SIMVACO, we focus on systematic process control, ensuring every drill performs consistently on the production line.
6. Trends: From Material Optimization to Integrated Manufacturing Systems
- Zoned coating strategies: Low-friction coatings for microvias, wear-resistant coatings for thick boards
- In-house coating capabilities: Improve yield, process stability, and production control
- Vacuum coating as a core competency: Stable coating directly impacts production yield and via consistency
7. SIMVACO’s Solution: Engineering-Driven Coating for High-Density PCB
SIMVACO provides:
- Controlled ultra-thin film deposition for microvia drills
- Low-stress, stable coating processes
- Batch consistency inspection and feedback systems
- Differentiated coating strategies to match industrial PCB requirements
Our approach combines material selection, deposition equipment, process control, and batch quality management, enabling high-yield, reliable HDI PCB mass production.
8. Conclusion: Precision Manufacturing for the AI Era
AI servers demand more than computing power—they drive precision, engineering rigor, and system integration in PCB manufacturing.
Microvias are the smallest geometric unit of a PCB, and coated drill bits are the key link between process stability and mass production reliability.
By integrating advanced coating technology, equipment capability, and process control, manufacturers can achieve consistent, high-quality HDI PCB production, meeting the next generation of AI server demands.
🔹 Why SIMVACO?
SIMVACO’s drill bit coating solutions help PCB manufacturers:
- Improve yield in high-density HDI PCBs
- Reduce microvia defects and breakage
- Maintain consistent production across large batches
- Integrate coating into the manufacturing system for full process control
Contact us today to learn how SIMVACO can support your next-generation PCB manufacturing.
Website: https://simvaco.com
WhatsApp: +86-15958205967