In modern electronics manufacturing, PCB holes play a critical role in both electrical connectivity and mechanical assembly. Whether used for mounting components or connecting internal layers in multilayer circuit boards, holes are fundamental to the performance and reliability of a Printed Circuit Board (PCB).
From traditional through-holes used in component mounting to advanced laser-drilled microvias in HDI PCBs, the evolution of PCB hole technology has enabled the miniaturization and high-density integration required by industries such as telecommunications, automotive electronics, medical devices, and consumer electronics.
This guide explains everything engineers and buyers need to know about PCB hole types, PCB hole sizes, drilling technologies, and PCB hole manufacturing processes, while also exploring real PCB drilling costs in 2026 and practical design considerations for high-reliability circuit boards.
1. What Are PCB Holes?
A PCB hole is a drilled opening in a printed circuit board used for electrical connections, component mounting, or mechanical positioning.
PCB holes are typically categorized into two primary functions:
Electrical Interconnection
Holes plated with copper allow signals and power to pass between layers in multilayer PCBs.
Mechanical Mounting
Non-plated holes provide structural support for components, connectors, or enclosure mounting.
Common uses include:
- Connecting internal layers in multilayer PCBs
- Mounting through-hole components
- Heat dissipation and grounding
- Mechanical alignment during PCB assembly
Because of these roles, the precision and quality of PCB drilling and plating processes directly affect board reliability.
2. The Role of PCB Holes in Circuit Board Design
PCB holes influence multiple aspects of circuit board performance.
Electrical Connectivity
Plated holes enable vertical electrical interconnection between layers in multilayer PCBs.
Component Installation
Traditional components such as capacitors, resistors, connectors, and transformers often require through-hole mounting.
Signal Integrity
Proper via and hole design helps maintain signal integrity, especially in high-speed digital and RF circuits.
Thermal Management
Some holes are used as thermal vias to dissipate heat from high-power components.
Designers must carefully balance hole size, annular ring, and spacing to meet manufacturing tolerances.
3. Main Types of PCB Holes
Modern PCBs use several types of holes depending on design complexity and performance requirements.
3.1 Through-Holes
A through-hole PCB hole passes completely through the circuit board from the top layer to the bottom layer.
Key characteristics:
- Mechanically drilled
- Copper plated
- Used for component mounting or signal connections
Advantages:
- Strong mechanical support
- Reliable electrical connection
- Suitable for power components
Limitations:
- Occupies more PCB space than microvias
3.2 Blind Vias
A blind via connects an outer layer to one or more inner layers but does not pass through the entire board.
Benefits:
- Saves PCB routing space
- Supports high-density PCB layouts
Blind vias are widely used in HDI PCB designs.
3.3 Buried Vias
A buried via connects only internal layers and is invisible from the outer surfaces of the PCB.
Applications:
- High-layer count PCBs
- Compact electronic devices
They are manufactured during multilayer lamination.
3.4 Microvias
A microvia is a very small via created using laser drilling technology.
Typical microvia characteristics:
- Diameter: 50–150 µm
- Used in HDI PCB technology
- Enables ultra-compact designs
Industries using microvias include:
- Smartphones
- wearable devices
- high-speed networking equipment
4. Plated vs Non-Plated PCB Holes
PCB holes can be divided into plated and non-plated holes.
Plated Through Holes (PTH)
These holes have a copper layer deposited on the internal wall.
Functions:
- Electrical signal transmission
- Layer interconnection
Typical plating thickness: 20–25 µm copper
Non-Plated Through Holes (NPTH)
NPTH holes do not contain copper plating.
Uses include:
- Mechanical mounting
- Heat sinks
- Alignment holes
Understanding the difference between PTH vs NPTH is important during PCB design and fabrication.
5. PCB Hole Size and Design Considerations
Selecting the correct PCB hole size is essential for manufacturability and reliability.
Typical PCB Drill Sizes
Common drill sizes range from: 0.15 mm – 6.5 mm
Example applications:
| Hole Size | Application |
| 0.15–0.30 mm | Microvias |
| 0.30–0.50 mm | Standard vias |
| 0.60–1.00 mm | Component leads |
| >1.00 mm | Mounting holes |
Annular Ring Requirements
The annular ring is the copper pad surrounding a hole.
Typical minimum: 0.10 mm – 0.15 mm
PCB Hole Tolerance
Standard tolerance: ±0.05 mm – ±0.075 mm
Precision drilling is essential to avoid:
- misalignment
- weak solder joints
- signal reliability issues
6. PCB Hole Drilling Technologies
The PCB drilling process determines the accuracy and reliability of hole formation.
Mechanical Drilling
The most common drilling method.
Features:
- CNC drilling machines
- Suitable for most PCB holes
- High productivity
Laser Drilling
Laser drilling is used to create microvias in HDI PCBs.
Advantages:
- Extremely small hole sizes
- High precision
- ideal for high-density PCB fabrication
7. PCB Hole Plating Process
After drilling, plated holes undergo a copper plating process.
Steps include:
- Hole cleaning
- Electroless copper deposition
- Electroplating
- Surface finishing
The copper layer ensures reliable electrical conductivity between PCB layers.
Quality inspections typically check:
- plating thickness
- hole wall integrity
- void defects
8. PCB Hole Design Guidelines for Engineers
Engineers should follow several PCB hole design rules.
Recommended Best Practices
- Maintain adequate annular ring width
- Avoid extremely high aspect ratios
- Ensure proper hole-to-hole spacing
- Use via-in-pad technology carefully
Typical aspect ratio limits: 8:1 to 10:1
Higher ratios may cause plating defects.
9. Applications of Different PCB Hole Types
PCB holes are used across many industries.
Consumer Electronics
Smartphones and laptops use microvias and HDI vias.
Automotive Electronics
Automotive control modules rely on reliable plated through holes.
Telecommunications
High-frequency networking equipment uses precision via structures.
Medical Devices
Medical electronics require high-reliability PCB drilling and plating processes.
10. Common PCB Hole Manufacturing Challenges
PCB hole production can encounter several challenges.
Drill Wander
Small deviations in drilling position.
Hole Wall Roughness
May reduce plating adhesion.
Plating Voids
Caused by poor chemical processing.
Layer Misalignment
Affects multilayer connectivity.
Experienced PCB manufacturers use advanced drilling equipment and inspection systems to minimize these issues.
11. PCB Drilling Cost in 2026
PCB drilling is a significant factor in PCB manufacturing cost, especially for boards with thousands of holes.
Typical PCB drilling cost range in 2026:
| Hole Type | Cost Range |
| Standard mechanical drilling | $0.0008 – $0.003 per hole |
| Small vias (<0.3 mm) | $0.002 – $0.006 per hole |
| Laser microvias | $0.01 – $0.05 per hole |
Cost factors include:
- number of holes
- hole size
- board thickness
- microvia technology
- production volume
For complex HDI PCBs with microvias, drilling costs may represent 15–30% of total PCB fabrication cost.
12. Advanced PCB Hole Manufacturing Capabilities
Leading PCB manufacturers continuously improve their drilling and via technologies.
For example, manufacturers like KingsunPCB provide advanced capabilities including:
- laser microvia drilling for HDI PCBs
- minimum drill size down to 0.15 mm
- high-precision CNC drilling
- multilayer PCB via structures
- strict IPC quality standards
These capabilities help OEM companies produce high-reliability multilayer circuit boards for demanding industries such as telecommunications, industrial automation, and medical electronics.
Reliable PCB suppliers also provide DFM support, helping engineers optimize hole design to reduce manufacturing cost and improve product reliability.
13. Future Trends in PCB Hole Technology
The electronics industry continues to push PCB hole technology forward.
Key trends include:
Ultra-Small Microvias
Used in advanced HDI PCBs.
Sequential Lamination
Enables complex buried via structures.
Laser Drilling Improvements
Higher accuracy and faster production.
AI-Driven Manufacturing
Automated inspection for drilling defects.
These technologies will support next-generation electronics such as AI hardware, 5G infrastructure, and high-performance computing.
14. FAQ About PCB Holes
Q1: What is the smallest PCB hole size?
In modern HDI PCB manufacturing, the smallest hole size can reach 0.10 mm to 0.15 mm using laser drilling technology.
Q2: What is the difference between a PCB via and a PCB hole?
A via is a type of plated hole used specifically to connect different PCB layers electrically, while a PCB hole may also serve mechanical purposes such as component mounting.
Q3: Are all PCB holes plated?
No. PCB holes can be either:
- Plated Through Holes (PTH) for electrical connections
- Non-Plated Through Holes (NPTH) for mechanical mounting
Q4: Why are microvias used in HDI PCBs?
Microvias allow high-density routing and are essential for compact electronic devices such as smartphones and wearable technology.
Q5: How many holes can a PCB contain?
A typical PCB may contain hundreds to tens of thousands of holes, depending on design complexity and board size.
15. Conclusion
PCB holes are fundamental elements of printed circuit board design and manufacturing. From traditional through-hole structures to advanced laser-drilled microvias, the evolution of hole technology has enabled modern electronics to become smaller, faster, and more reliable.
Understanding PCB hole types, drilling processes, design rules, and manufacturing costs helps engineers design more efficient circuit boards while allowing buyers to choose the right PCB manufacturing partner.
As PCB technology continues to evolve, innovations in HDI structures, microvia drilling, and advanced fabrication processes will further expand the possibilities of electronic product design.