Förklaring av kopparpläteringsprocessen vid PCB-tillverkning

Copper plating is a critical step that turns drilled holes into reliable electrical connections.
No matter how well a PCB is designed, poor copper plating can lead to:

• Intermittent connections
• Via cracking
• Premature product failure

From a manufacturer’s perspective, copper plating is not just a chemical process—it is a reliability gate.

This article explains how copper plating works in PCB manufacturing, the different plating stages, and how manufacturers like TOPFAST control plating quality to ensure long-term performance.

What Is Copper Plating in PCB Manufacturing?

Copper plating is the process of depositing copper onto PCB surfaces and inside drilled holes to create electrical connections between layers.

Plating serves two main purposes:

• Enable electrical continuity through vias
• Achieve the required copper thickness for current and reliability

Types of Copper Plating in PCB Manufacturing

Electroless Copper Plating

Electroless copper plating deposits a thin, uniform copper layer without using electrical current.

Syfte

• Create an initial conductive layer inside drilled holes
• Prepare the PCB for electroplating

Typical thickness:

• ~1–3 microns

This step is essential for making vias electrically functional.

Electrolytic Copper Plating

Electroplating uses electrical current to build up copper thickness.

Syfte

• Strengthen via walls
• Increase surface copper thickness
• Meet design copper specifications

Electroplating determines:

• Via reliability
• Current-carrying capacity
• Mekanisk styrka

Step-by-Step Copper Plating Process

Step 1 – Hole Wall Preparation

After drilling, the hole walls must be:

• Cleaned
• Desmeared
• Activated for copper deposition

Poor preparation leads to weak copper adhesion.

Step 2 – Electroless Copper Deposition

A thin copper layer is deposited chemically, ensuring:

• Uniform coverage
• Electrical continuity

This layer is the foundation for all subsequent plating.

Step 3 – Electroplating Thickness Build-Up

Copper thickness is increased through controlled electroplating.

Key parameters include:

• Current density
• Bath chemistry
• Temperatur
• Plating time

Consistency here is crucial for reliability.

Plating Thickness and Why It Matters

Via Wall Thickness

Via reliability depends heavily on:

• Minimum copper thickness
• Uniform distribution

Insufficient copper can cause:

• Cracks during thermal cycling
• Open circuits

Surface Copper Thickness

Surface copper affects:

• Trace current capacity
• Etching performance
• Impedansreglering

At TOPFAST, plating thickness is carefully matched to design requirements to avoid over- or under-plating.

Common Copper Plating Defects

H3: Thin Plating

Orsakad av:

• Insufficient plating time
• Poor current distribution

Results in reduced reliability.

Void Formation

Voids inside vias can occur due to:

• Poor hole cleaning
• Incomplete electroless coverage

Voids are a major reliability risk.

Uneven Plating

Uneven copper distribution leads to:

• Weak via walls
• Impedance variation
• Yield loss

How Copper Plating Affects PCB Reliability

Copper plating quality directly impacts:

• Thermal cycling performance
• Mechanical stress resistance
• Long-term electrical stability

In high-reliability applications, plating quality often matters more than board appearance.

Design Factors That Influence Plating Quality

From a manufacturing perspective, plating becomes more challenging when:

• The aspect ratio is too high
• The hole size is too small
• Copper distribution is uneven
• Heavy copper designs are used

Early DFM review helps identify plating risks before production.

Manufacturer’s Perspective: How TOPFAST Controls Plating Quality

At TOPFAST, copper plating quality is ensured through:

• Controlled chemical bath management
• Real-time thickness monitoring
• Regular cross-section analysis
• IPC-aligned acceptance standards
• DFM-driven design feedback

The focus is on stable yield and long-term reliability, not just meeting minimum specifications.

Cost Considerations of Copper Plating

Copper plating cost increases with:

• Heavy copper requirements
• Vior med högt aspektförhållande
• Tight thickness tolerances
• Advanced reliability specifications

Optimising plating requirements can significantly reduce PCB cost without compromising performance.

Slutsats

Copper plating is one of the most critical processes in PCB manufacturing.
It transforms drilled holes into durable electrical connections and defines PCB reliability.

By understanding how copper plating works and what affects its quality, designers and buyers can make smarter decisions that balance cost, performance, and reliability.

With controlled processes and manufacturing expertise, TOPFAST ensures copper plating quality that supports reliable PCB performance throughout the product lifecycle.

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