Right PCB Thickness
Designing a PCB is not just about converting a schematic into a physical form, it's also about PCB thickness. PCB thickness is equally important to ensure its proper and long-lasting function, which determined PCB layers. A single PCB layer consists of layers of different materials laminated together by heat. The following layers of PCB can be fabricated in many different thicknesses.
1.Copper layer: Both sides of FR4 is covered with copper foil. It can be used as a laminator for PCBs and thermal adhesives. The thickness of the copper foil is different. PCBs for high-power applications use 3 to 4 ounces of copper per square foot. On a single-layer PCB, the copper layer only exists on one side, but as the number of PCB layers increases, the number of layers can increase to 18 layers or more.
2.Fiberglass: Also known as FR4, is the substrate which gives PCB its thickness and makes it rigid. The most common thickness using a weak quality of FR4 is commonly found in protoboard like Varo board. They are cheap but can not tolerate too much soldering heat due to the low thermal decomposition temperature. Otherwise, the PCB will get delaminate, burn and emit an awful smell. Therefore, the durability of the FR4 is determined by the assembly time needed for the components and its application.
3.Silkscreen: This layer is usually white and adds reference marks, symbols, numbers, and other information that indicate the function of the PCB like its individual pins. This allows users to assemble PCBs easily, and helps technicians and non-technicians to understand the purpose of PCBs.
4.Solder mask: It can offer PCB various colors like green, purple, red, etc. It covers over the copper layer except for SMD pads and solver rings for through-hole component footprints. Solder mask insulates copper traces to avoid any contact of solder or metal with the copper layer. It also makes the soldering user friendly and gives assembled components a finishing touch.
The above four points determine the PCB thickness. Therefore, before sending to the manufacturer, make sure to specify the number of layers and the finished PCB thickness in the Gerber file.