How Thick Is A 6 Layer PCB Stackup?

In general, a six-layer PCB consists of two additional signal layers inserted between the planes on a four-layer PCB. Four routing layers two outer and two inner as well as two internal planes one for ground and the additional one for power are part of the traditional six-layer PCB stackup. By providing two surface layers for low-speed signal routing and two subsurface layers for high-speed signal routing, this significantly improves the EMI. The neighbouring planes should not have access to the signal layers.

Tutorial and Design Software for Layer PCB Design

The design of the 6-layer board of electronics will be greatly impacted by the creation of an appropriate stack structure. Fortunately, PCB design software is getting more and more effective these days, and you may use it to fully finish the laminated design you require.

The design above is the standard 6 layer pcb stackup. But it is not suitable for every design. For example, systems that require minimal electromagnetic emissions could need to include extra ground planes for shielding, while high speed designs will usually always keep both power and ground aircraft on adjacent levels for decoupling. 

A 6-layer PCB stackup’s thickness might vary based on a number of variables, such as the materials utilized, the design requirements, and the manufacturer’s capabilities. I can offer a basic recommendation, though, regarding the usual thickness of a normal 6-layer PCB stackup:

Core Thickness: 

In a six-layer PCB, the core layer is often the thickest layer. Although the thickness might vary, a typical core thickness is approximately 0.062 inches (1.57 mm). Usually, a substrate made of a non-conductive product, like FR-4 (a kind of fiberglass-reinforced epoxy laminate), makes up this core layer.

Prepreg Thickness: 

The inner layers and the core are joined together with Prepreg, a fiberglass substance soaked with resin. Although the prepreg layers’ thickness varies, they typically range from 0.002 to 0.005 inches (0.05 to 0.13 mm) each. Multiple prepreg layers are possible in a PCB stackup.

Copper Thickness: 

The total PCB thickness is also influenced by the degree of thickness that is applied to the copper foil used in the inner layers. One ounce (about 1.4 mils or 0.035 mm) or two ounces (about 2.8 mils or 0.071 mm) of copper per square foot are common choices for thickness. 

Why Use 6 Layers?

Before starting a board, I think it’s important to consider the reasons one might want to use a pcbasic 6-layer PCB. More than just increasing the number of signal routes, there are other factors. The simplest 6-layer stackup will use the same methodology as a SIG/PWR/GND/SIG stackup in a 4-layer board and simply place signal on two extra layers in the stackup’s center. 

I would choose a 6-layer board versus a 4-layer board for a number of reasons, including:

In your 4-layer SIG+PWR/GND/GND/SIG+PWR stackup, there should have been more space for components on the surface layer. More separation with a PWR/GND plane pair is achieved by placing PWR and SIG in the inner layers.

2. An additional internal layer will be present for slower digital routing on mixed signal boards, and the entire surface layer can be devoted to the analog interfaces.

3. Using a high-speed board with a high I/O count, you need to find a reliable method for dividing signals into various board layers. You can use the same plan of action as in point #1.

Instead of adding two extra signal layers, you’re only adding one in each of these combinations. A GND plane, voltage rails, or a whole power plane occupy the other tier. Along with layout and routing strategy, your stackup will be the primary predictor of EMC and integrity of signals in your board.