Multi-layer PCBs are printed circuit boards with more than two layers of copper, such as 4-layer, 6-layer, 8-layer, 10-layer, 12-layer, and so on. With advancements in technology, it is now possible to manufacture PCBs with 20 to 32 layers of copper.

This structure allows engineers to allocate different layers for various functions, such as power distribution, signal transmission, EMI shielding, and component mounting. To manage the complexity and avoid excessive layering, buried vias and blind vias are often incorporated into multi-layer PCBs. For boards with more than 8 layers, high Tg FR4 material is preferred over standard Tg FR4 due to its enhanced thermal properties.

The manufacturing process becomes more complex and costly as the number of layers increases. Consequently, the lead time for multi-layer PCBs is typically longer compared to standard PCBs. For precise lead time, please contact us directly.

A multi-layer PCB is a complex and sophisticated printed circuit board that consists of multiple layers of conductive copper and insulating material. Here’s a detailed breakdown of its structure:

• Core Material
  FR4 Core: The central layer is typically made of FR4, a fiberglass-reinforced epoxy laminate that provides structural integrity and insulation. This core material can also be a pre-preg (a composite material made of fiber reinforcements pre-impregnated with a resin matrix).
• Copper Layers
  Inner Layers: Multiple inner layers of copper foil are laminated onto the core material. These layers are used for routing electrical signals, power distribution, and grounding.
  Outer Layers: The top and bottom layers are also copper foils, which can be used for component mounting and additional routing.
• Pre-preg (Pre-impregnated Composite Fibers)
  Insulating Layers: Between each copper layer, there are layers of pre-preg. This material acts as an insulating barrier and provides mechanical strength to the PCB. The pre-preg layers are cured and bonded under heat and pressure during the lamination process.
• Vias
  Through-Hole Vias: These vias pass through the entire PCB, connecting all layers.
  Blind Vias: These vias connect outer layers to one or more inner layers but do not go through the entire board.
  Bured Vias: These vias connect only the inner layers and are not visible from the outer layers of the board.
• Solder Mask
  Protective Coating: A layer of solder mask is applied to the outer surfaces of the PCB. This layer protects the copper traces from oxidation and prevents solder bridges during component soldering.
• Silkscreen
  Identification Markings: The silkscreen layer is applied on top of the solder mask. It includes printed information such as component labels, logos, and other identifiers.