4-Layer PCB with 4oz Copper and Dual Aluminum Heat Sink Stack-up

4-layer PCBs are common printed circuit board options for industrial controls and mid- to high-end consumer electronics. 4oz-copper PCBs belong to thick-copper PCBs and are used for high-power applications such as automotive, industrial controls, aerospace, and medical electronics.

Have you ever designed a 4-layer PCB with 4oz copper thickness? PCBONLINE, a one-stop PCB manufacturing and assembly manufacturer, provides 4-layer PCBs with copper thicknesses up to 14oz.

In this article, we will showcase a 4-layer PCB with a layer stackup of 4oz copper (Cu) – prepreg (PP) – aluminum (Al) – PP – 4oz Cu – FR4 – 4oz Cu – PP – Al – PP – 4oz Cu. For easier understanding, it is a 4-layer PCB with 4oz copper and dual aluminum heat sink stackup.

Stackup of This 4-Layer 4oz Copper PCB

Our 4-layer 4oz copper PCB with a dual aluminum heat sink stack-up essentially consists of a standard 4-layer FR4 PCB laminated between two outer aluminum layers for enhanced heat dissipation.

From top to bottom, this 4-layer 4oz copper PCB with dual aluminum heat sink stackup consists of:

• Top copper layer (signal or power)
• Prepreg (dielectric bonding layer)
• Aluminum plate (top heat spreader)
• Prepreg (insulation layer between Al and inner copper)
• Inner copper layer 1
• FR4 core (main dielectric and mechanical support)
• Inner copper layer 2
• Prepreg
• Aluminum plate (bottom heat spreader)
• Prepreg
• Bottom copper layer

In the 4-layer PCB with dual aluminum heat sinks, the outer aluminum layers act as heat spreaders, not electrical layers. Its insulating prepregs between copper and aluminum are used for dielectric isolation.

This thermal-enhanced aluminum sandwich stack-up PCB is used where high heat dissipation is critical, such as power modules, LED drivers, and motor controllers. If you need OEM PCB manufacturing for industrial control and power devices, consider ordering such cool and interesting thermal-enhanced PCBs from PCBONLINE!

More of 4-Layer and Thick-Copper PCBs

The 4-layer 4oz copper PCB in this article is a showcase of what thick-copper and multilayer PCBs PCBONLINE can make. In fact, this is a special thermal-enhanced structure, not a common 4-layer stack-up. It is more costly than standard multilayer PCBs.

For reference, the following are the more common 4-layer PCB stack-ups used in most designs.

Standard FR4 4-layer stack-up

• Top Cu (Signal) - thickness 1oz or 2oz
• Prepreg - thickness about 0.1 mm
• Inner Cu 1 (Ground Plane)
• Core (FR4) - thickness about 0.8mm
• Inner Cu 2 (Power Plane)
• Prepreg
• Bottom Cu (Signal)

A standard FR4 4-layer PCBs have a total thickness of about 1.6 mm. It is used for general digital circuits, analog circuit boards, and low-power devices.

High-current/heavy copper stack-up

• Top Cu - thickness 2oz to 10oz
• Prepreg
• Inner Cu 1
• Core (FR4)
• Inner Cu 2
• Prepreg
• Bottom Cu

At PCBONLINE, we can make the copper thickness up to 14oz. However, it is common to see heavy copper requirements of 10oz and below. Sometimes, our clients require PCBs reinforced with thermal vias or PCB busbars.

These heavy-copper PCBs are used for power converters, automotive electronics, motor drives, and industrial controls.

Hybrid or high-frequency stack-up

• Cu
• Prepreg (Rogers 4350B)
• Core (high-performance FR4)
• Cu
• Prepreg (high-performance FR4)
• Cu
• Prepreg (high-performance FR4)
• Cu
• Prepreg (Rogers 4350B)
• Cu

A Rogers FR4 hybrid 4-layer stackup is used for RF or high-frequency PCBs, where Rogers + FR4 hybrid lamination controls impedance and loss.

Partner with PCBONLINE for 4-Layer and 4oz Copper PCBs

If you need one-stop heavy-copper and multilayer PCB manufacturing and assembly, you can partner with PCBONLINE. PCBONLINE is an OEM PCB manufacturer that provides standard multilayer FR4 PCBs, Rogers FR4 PCBs, heavy-copper PCBs, and thermal-enhanced 4-layer 4oz copper PCBs showcased in this article.

Founded in 2005, PCBONLINE has two large advanced PCB manufacturing bases, one PCB assembly factory, stable supply chains, and an R&D team for one-stop PCBA manufacturing.

No matter what power applications of your PCB are, like automotive, aerospace, medical devices, industrial controls, and mid- to high-end consumer electronics, PCBONLINE can produce and assemble PCBs that meet the highest performance and reliability standards. To get a quote for your PCB project, contact info@pcbonline.com.

Conclusion

This article showcases a special 4-layer 4oz copper PCB with dual aluminum heat sinks. It is essentially a 4-layer FR4 PCB laminated between two outer aluminum layers for enhanced power density and heat dissipation. If you're designing a thick-copper and multilayer PCB, PCBONLINE can provide one-stop PCB manufacturing for you.