Introduction: Printed Circuit Boards Layers
This article will show some basics information should be known about PCBs!
At the beginning, what is PCB???
PCB is a “Printed circuit board” which contains of electrical circuit whose components and conductors are contained within a mechanical structure.
Conductive features include copper traces, pads, heat sinks, or conductive planes. The mechanical structure is made with insulating material laminated between layers of conductive material. The overall structure is plated and covered with non-conductive solder mask and silk screen to legend electronic component location.
Step 1: Types of PCBs
There are many types of PCBs like :
Single-Sided PCBs
Double-Sided PCBs
Multilayer PCBs
Rigid PCBs
Flex PCBs
Rigid-Flex PCBs
in this article, we will talk about the layers of single and doubled sided PCBs.
Step 2: The Substrate Layer (FR4).
The base material, or substrate, is usually fiberglass. Historically, the most common designator for this fiberglass is "FR4". This solid core gives the PCB its rigidity and thickness. There are also flexible PCBs built on flexible high-temperature plastic (Kapton or the equivalent).
Step 3: The Copper Layer.
it is a thin copper foil, which is laminated to the board with heat and adhesive. On common, double sided PCBs, copper is applied to both sides of the substrate. In lower cost electronic gadgets, the PCB may have copper on only one side. When we refer to a double sided or 2-layer board we are referring to the number of copper layers (2).
Step 4: the Soldermask Layer.
The layeron top of the copper foil is called the soldermask layer. This layer gives the PCB its green color. It is overlaid onto the copper layer to insulate the copper traces from accidental contact with other metal, solder, or conductive bits. This layer helps the user to solder to the correct places and prevent solder jumpers.
Soldermask is most commonly green in color but nearly any color is possible.
Step 5: The Silk Screen Layer.
The white silkscreen layer is applied on top of the soldermask layer. The silkscreen adds letters, numbers, and symbols to the PCB that allow for easier assembly and indicators for humans to better understand the board. We often use silkscreen labels to indicate what the function of each pin or LED.
