A PCB is called Multilayer PCB, if it has 3 or more layers(sheets) of copper foil, insulated from each other(by lamination or coating) and joined together to form a single piece. Pcbcircuit is the best multilayer PCB manufacturer In India.
A Multilayer PCB has an Inner Layer Core present at the center of all the layers and coated with a Copper layer from both sides, while layers of prepreg(woven glass cloth with epoxy resin) are used for insulation.
More Powerful :
Multilayer PCBs are extremely high-density assemblies, incorporating multiple layers into one PCB.
Lightweight Construction :
With smaller PCBs comes less weight, especially because the multiple connectors required to interlink separate single and double-layered PCBs are eliminated in favor of a multilayered design.
Increased Durability :
Multilayer PCBs tend to be durable by their nature. Not only do these multilayer PCBs need to withstand their own weight, but they need to even be able to handle the warmth and pressure want to bind them together.
Small Size :
One of the foremost prominent and lauded benefits of using multilayer PCBs lies in their size. Due to their layered design, multilayer PCBs are inherently smaller than other PCBs with similar functionality.
Enhanced Flexibility :
Though this doesn’t apply to all or any multilayer PCB assemblies, some do use flexible construction techniques, leading to a versatile multilayer PCB. A multi-color PCB (Printed Circuit Board) refers to a circuit board designed with multiple colors of solder mask and possibly different colored substrates.
Multilayer PCB Manufacturing Process :
The process starts with designing Layout of the PCB using any PCB designing software / CAD Tool (Proteus, Eagle, OrCAD).
Next step is to create the Inner Layer Core. Laminate of desired thickness is treated with copper foil, dry film resists and UV light to create the inner layer core.
Next step is lamination. This process include: Inner layer core, prepeg sheets and copper foil sheets. The sheets of fabric are staked on one another and holes are wont to align them as they’re stacked up.
For a 4 layer board, Staking of layers is as follows: Bottom Layer of Copper Foil – Prepeg Sheets – The Inner Layer Core – More Prepeg Sheets – Finally Copper Foil Sheet on Top.
Next step is to use pressure, heat and vacuum employing a heated mechanical press. Vacuum is vital to create sure there’s no air trapped between the layers. This process ends over 2 hours betting on the number of layers.
Once cured, resins from the prepegs join the sheets, core, and foil together forming a multilayer PCB.
