The Printed Circuit Board (PCB) is the heart of all modern electronics. From the smartphone in your hand to complex aerospace systems, their reliability begins with a precise and strictly controlled manufacturing process. How is a high-quality PCB board created from raw materials?
Phase 1: Inner Layer Preparation & Imaging

◆ Cutting

Large CCL (Copper Clad Laminate) or PP (Prepreg) are cut into production-sized panels to facilitate subsequent processes.

◆ Inner Layer Imaging

The inner layer circuitry is imaged and etched to form circuit patterns, providing the electrical structure for multilayer boards.

◆ AOI (Automatic Optical Inspection)

Automatic Optical Inspection is performed to detect defects such as shorts, opens, or residual copper on the inner layers. This is a critical quality control check to ensure the integrity of the internal circuitry. 

Phase 2: Lamination, Drilling & Plating

◆ Lamination

Inner cores, PP, and copper foils are stacked and bonded together under high temperature and pressure to form a multilayer board.

◆ Drilling

Through holes (PTH), blind vias, or buried vias are drilled to create interlayer electrical connections. These holes are the pathways that connect the different layers of the PCB.

◆ Electroless Copper Deposition

A thin layer of copper is chemically deposited on the non-conductive hole walls to form a conductive base layer for subsequent electroplating.

Phase 3: Outer Layer & Protective Coatings

◆ Plating

Copper thickness is increased on hole walls and traces through electrolytic plating to improve conductivity and mechanical strength.

◆ Outer Layer Imaging

The final outer layer circuitry is imaged, plated, and etched to define the board’s external circuit pattern. This step creates the surface traces you see on a finished board.

◆ Solder Mask

A green (or other color) solder resist layer is applied to protect copper traces, prevent solder bridging during assembly, and improve electrical insulation.

◆ Silkscreen Printing

Component reference designators, markings, and company logos are printed on the board surface for identification and assembly guidance.

Phase 4: Surface Finish, Profiling & Final Testing

◆ Surface Finish

A protective and solderable surface coating is applied to the exposed pads (where components will be soldered) to prevent copper oxidation and ensure solderability. Common finishes include OSP, ENIG, or HASL.

◆ Profile

Boards are cut, routed, or V-scored to the required mechanical outline per product specifications. This step separates the individual boards from the production panel.

◆ Electrical Testing

Continuity and isolation tests are performed to verify the electrical integrity of the circuits, ensuring all nets are correctly connected or isolated. This is a 100% check to guarantee functionality.

◆ Final Inspection and Packaging

Final inspection checks appearance, dimensions, flatness, and solder mask quality. This is the last quality gate before packaging.Qualified boards are vacuum-packed or moisture-protected for shipment.

From a simple copper-clad laminate to a complex component-ready circuit board, the PCB manufacturing process is a sophisticated blend of chemistry, physics, and precision engineering. Every step must be meticulously controlled to ensure the high reliability of the final product.

Operations Center

Add: Bldg D,Liantangkeng Industrial Area,Qianjin Road,Xixiang Street,Bao'an Dist.,Shenzhen City,Guangdong Province,518102,China.

Tel: +86 755 2794 4155

Fax: +86 755 2794 4159

E-mail: sales@knownpcb.com