How To Make PCB

by Topfast | Wednesday May 28 2025

PCB (Printed Circuit Board) is the core component of modern electronic devices. Understanding its manufacturing process is crucial for both electronics enthusiasts and professionals. This article adopts a Q&A format to detail the complete PCB fabrication process, covering every step from design to finished product while maintaining both professionalism and accessibility.

Basic Concepts of PCB Manufacturing

What is a PCB, and why is it so important?

A PCB (Printed Circuit Board) is a substrate used to support and connect electronic components, achieving electrical connections between components through copper traces. It serves as the backbone of all electronic devices, from smartphones to spacecraft.

The importance of PCBs manifests in three aspects:

Reliability: Replaces hand-soldered flying wires, reducing connection errors
Standardization: Enables mass production and automation of electronic devices
High Density: Modern multilayer PCBs can implement complex circuits in limited space

What are the main methods for making PCBs?

Depending on the production environment and requirements, there are several primary PCB fabrication methods:

Professional Factory Production:

Suitable for: Mass production, high-precision requirements
Processes: Photochemical methods, electroplating processes
Layers: Can produce single-sided, double-sided, and multilayer boards (4-layer, 6-layer or more)

DIY Handmade Methods:

Suitable for: Prototyping, simple circuits
Common methods:
Heat Transfer Method: Uses a heat press machine to transfer printed circuit patterns from special paper to copper-clad boards
Photosensitive Board Method: Uses photosensitive copper-clad boards with exposure and development processes
Hand Drawing Method: Uses special oil-based pens to draw circuits directly on copper-clad boards

PCB Design Phase

How to begin designing a PCB?

PCB design is the first and most critical step in the manufacturing process:

Circuit Design:

Use EDA software (like Altium Designer, Eagle, KiCad) to draw schematics
Determine component parameters and connection relationships

PCB Layout:

Convert schematics to actual PCB layouts
Consider component placement, trace routing, and interlayer connections

Design Verification:

Electrical Rule Check (ERC)
Design Rule Check (DRC)
Signal Integrity Analysis (for high-frequency circuits)

What professional PCB design software is recommended?

Depending on needs and skill level, consider these options:

Software	Target Users	Features	Price
Altium Designer	Professional Engineers	Comprehensive features, industry standard	High
Eagle	Small-Medium Businesses	Rich component libraries, Autodesk product	Medium
KiCad	Hobbyists/Students	Open source, powerful features	Free
Proteus	Education Sector	Combining simulation with PCB design	Medium

Professional PCB Factory Manufacturing Process

What does the professional PCB factory manufacturing process look like?

Professional PCB factory processes are complex and precise. Taking a 4-layer board as an example:

Inner Layer Production:

Core board cleaning → Photoresist coating → Exposure → Development → Etching → Stripping

Lamination:

Stack core boards with prepreg (pre-impregnated materials)
High temperature and pressure bonding

Drilling:

Mechanical drilling or laser drilling
Creates through-holes, blind vias or buried vias

Hole Metallization:

Electroless copper deposition → Electroplating thickening
Makes the walls conductive for interlayer connections

Outer Layer Production:

Similar photolithography process as inner layers
Pattern plating to increase copper thickness

Solder Mask & Silkscreen:

Apply solder resist ink (typically green)
Print component identifiers and reference designators

Surface Finish:

Options like HASL, ENIG, OSP
Protects pads and improves solderability

Routing & Testing:

Milling or V-cut scoring
Electrical testing (flying probe or test fixture)

Why do multilayer PCBs require such complex processes?

The complexity of multilayer PCBs (like 4-layer or 6-layer boards) stems from:

Layer Alignment: Each layer's circuits must align precisely (typically <50μm tolerance)
Interlayer Insulation: Must maintain insulation between signal layers
Reliable Interconnects: Plated through-holes ensure layer connections with conductive continuity
Signal Integrity: High-frequency signals require impedance control and crosstalk consideration

These requirements make multilayer PCB manufacturing a precision process combining electronics, chemical engineering, and mechanical technologies.

DIY PCB Fabrication Methods

How to make simple PCBs at home?

For electronics hobbyists, the heat transfer method is commonly used:

Materials Needed:

Copper-clad board (single or double-sided)
Laser printer
Heat transfer paper
Etching solution (ferric chloride or hydrochloric acid + hydrogen peroxide)
Drilling tools (small electric drill)

Steps:

Design & Print:

Complete layout using PCB design software
Print the mirror image on heat transfer paper

Pattern Transfer:

Press the printed side onto the cleaned copper-clad board
Apply heat using an iron or a heat press machine (160-200°C)

Etching:

Submerge in the etching solution to remove exposed copper
Monitor the process to avoid over-etching

Cleaning & Drilling:

Remove the transfer toner with solvent
Drill holes according to component lead sizes

Solder Preparation:

Apply rosin flux solution to prevent oxidation
Verify circuit connectivity

What precautions should be taken for DIY PCB fabrication?

Safety First:

Etching solutions are corrosive—wear gloves and goggles
Work in well-ventilated areas

Precision Control:

Recommended minimum trace width: 0.3mm
Recommended minimum clearance: 0.2mm

Troubleshooting:

Incomplete transfer: Touch up with an oil-based pen
Incomplete etching: Check solution concentration and temperature
Drilling misalignment: Use a center punch first

Environmental Considerations:

Collect and properly dispose of waste etching solution
Never pour down drains

Advanced PCB Knowledge

How to choose appropriate PCB materials?

PCB material selection considers these factors:

Base Material Types:

FR-4: Most common, fiberglass epoxy, cost-effective
High-Frequency Materials: Like Rogers, for RF/microwave circuits
Flexible Materials: Polyimide, for flex circuits

Key Parameters:

Tg (Glass Transition Temperature): ~130-140°C for standard FR-4
Dielectric Constant: Affects signal propagation speed
Loss Tangent: Critical for high-frequency applications

Copper Weight Selection:

Standard: 1oz (35μm)
High Current: 2oz or thicker
Precision Signals: 0.5oz allows finer traces

What are the PCB surface finish options and their characteristics?

Comparison of common PCB surface finishes:

Finish Type	Advantages	Disadvantages	Typical Applications
HASL	Low cost, good solderability	Uneven surface, not for fine pitch	Consumer electronics
ENIG	Flat surface, oxidation resistant	Higher cost, black pad risk	HDI boards, contact points
OSP	Low cost, simple process	Short shelf life, limited rework	Short-life consumer products
Immersion Silver	Good solderability, high-frequency suitable	Prone to oxidation, special packaging needed	RF circuits, automotive
Electrolytic Gold	Low contact resistance, wear-resistant	Highest cost	Connectors, high-reliability

PCB Quality Control and Testing

How to ensure PCB manufacturing quality?

PCB quality control spans the entire production process:

Raw Material Inspection:

Copper-clad board thickness and quality
Prepreg resin content and flow characteristics

Process Control:

Trace width/space measurement (typically optical equipment)
Hole wall quality inspection (cross-section analysis)
Layer-to-layer alignment verification

Final Testing:

Electrical testing (opens/shorts)
Impedance testing (for high-speed designs)
Solderability testing

Reliability Testing (as needed):

Thermal stress testing (e.g., 288°C solder float)
Humidity aging tests
Mechanical strength tests

What are common PCB defects and how can we prevent them?

Common defects and preventive measures:

Opens/Shorts:

Cause: Incomplete etching or over-etching
Prevention: Optimize etch parameters, increase inspection frequency

Hole Wall Separation:

Cause: Poor drilling quality or electroless copper issues
Prevention: Improve drilling parameters, enhance hole cleaning

Pad Lifting:

Cause: Excessive thermal stress or poor adhesion
Prevention: Optimize soldering profile, select high-Tg materials

Impedance Deviation:

Cause: Inconsistent dielectric thickness or trace width
Prevention: Tight dimensional control, precision processing equipment

PCB Manufacturing FAQ

How long does PCB manufacturing take?

Production time depends on process complexity and factory schedule:

Standard Processes:

Single-sided: 1-2 days
Double-sided: 2-3 days
4-layer: 3-5 days

Special Processes:

Impedance-controlled: Add 1-2 days
Heavy copper (≥3oz): Add 2-3 days
Blind/buried vias: Add 3-5 days

Note: Above are production times, excluding logistics. Rush services typically reduce time by 30-50% at a higher cost.

What factors determine PCB manufacturing costs?

Primary cost factors:

Material Costs (~20-30% of total):

Base material type (FR-4 vs high-frequency)
Board thickness and copper weight
Special materials (e.g., metal core)

Process Costs (~40-50% of total):

Layer count (each additional layer increases cost 30-50%)
Hole size and quantity (small holes <0.3mm increase cost)
Surface finish type

Design Complexity Costs:

Trace width/space (finer features increase cost)
Special requirements (impedance control, blind vias)

Order Quantity:

Small batches (<5m²) have higher unit cost
Large volumes significantly reduce per-unit cost

Future Trends in PCB Technology

What are emerging directions in PCB technology?

PCB technology continues evolving with key trends including:

High Density Interconnect (HDI):

Finer traces/spaces (down to 50μm/50μm)
More microvias (laser drilling technology)

Flexible/Rigid-Flex Boards:

Adaptable for wearables and foldable devices
Enables 3D assembly, saves space

Embedded Components:

Bury passive components within the PCB
Increases integration, improves electrical performance

Green Manufacturing:

Lead-free, halogen-free materials
New processes reducing chemical waste

Smart PCBs:

Integrated sensors and data processing
Enables self-monitoring and diagnostics

Through this detailed guide, you should now have a comprehensive understanding of the complete PCB fabrication process. Whether choosing professional manufacturing or DIY approaches, grasping these principles and techniques will help you obtain better PCB products. As technology advances, PCB manufacturing processes continue innovating, providing the foundation for electronic device miniaturization and high-performance applications.