FS Technology's introduction to the layers of the PCB.

Electronic Design Automation (EDA). It is a software used to design PCB and likewise confirm integrated circuits (ICs). There are different kinds available in PCB single ,double sided, High layer Count(multilayer), control impedance, Aluminum backed PCB and many more. This picture shows a single sided PCB which has four-layer basic layer.  

4-layer base layer single-sided PCB

PCB is based in separate layers, joined organized with the help of heat and adhesive. That makes many different layers into one single object.  More layers complex the design and it develops difficult route for your connections. A multilayer board have metallic linking with holes that attach to each other with suitable route. FS PCB will explain each layer of the printed circuit board in detail in the following content.

Silkscreen layer

The silk screen layer is the text layer, which can be dyed or painted on the board. It contains labels to aids in joining component to the circuit and adds letters, numbers and many signs to make it easier to comprehend. Silkscreen has no restrictions, it can be red, green or black or even none. The designer of FS Technology once saw such a post in a PCB manufacturing forum: “Why do Chinese manufacturers like to mark some messy symbols on the silk screen layer of the circuit board.” If you object to this practice, you can communicate with our sales.

PCB silk screen layer

Solder mask

Solder mask is a thin layer that is applied on copper layer on PCB. This is the upper layer which is overhead the copper foil. It is used to evade conduction in case of direct touch of any metal or solder. It is usually in green and black but make sure that it can be in any color. Solder mask plays an important role in the reflow process, and designers can prevent solder defects by reducing the spacing around the pads.

PCB Solder Mask

Rigid Copper Clad Laminate (copper Layer)

This is a slim layer on PCB of copper foil. It is coated on PCB board with adhesive and heat. Normally, both sideways of substrate are coated with copper apart from single-sided PCB. When we say different layers of PCB that where we count how many numbers of coper layer PCB has. The copper clad laminates are connected to each other through holes, and we can place different types of objects on it, such as:

  • Tracks
  • Individual pads
  • Vias 

PCB tracks or trace

Tracks are sometimes stated as PCB trace. It is used to join two points in the PCB, conduct. It spread signals and power to each other. Tracks can be very in thickness and resistance. The bigger the track, the more current it conveys. And if the track is stripper than it would be easy to fit more tracks. 

Pads

PCB pads are commonly exposed area of metal that allows soldering the component to the board. They can be in rectangle, ovel or round shape. A circuit is occupied with many holes if it is a multilayer layer PCB. Pads should be minimum of 0.25mm.

Vias

Vias in PCB used to connect different track. It is plated hole that allows the current to pass over the board. The tracks and pads that fits to the lowest layer are visually dimmed so one can distinguish.

Fills

In PCB fills provides shielding in divergent parts and likewise protect the tracks that carries a lot of current. 

FR4 Substrate Layers

Substrate use in PCB is the material which hold the components and trace. Printed circuit board composed of fiber glass that part is recognized as substrate.

FR means Flame Retardant and 4 represents epoxy resin. There are many glass epoxy laminates likeFR-5, FR-6, G-10 G-11. But FR-4 epoxy resin is used mostly.  The FR4 fiber glass in now commonly used in todays PCB. It is durable and available in different types of thickness.

Properties of FR4 substrate

  • Fine Electrical retardant 
  • Flame retardant
  • Low Moisture captivation 

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