Inner Layers are also know as the internal layers of a multilayer PCB.
The laminate and dielectric thicknesses as well as the copper weights of inner layers are predefined for our Standard Constructions.
By selecting non-standard construction on the order form and uploading your desired material stack up, the thickness and copper weight of these inner layers can be customized to meet your needs. The minimum manufacturable trace widths and spacing are based on the copper weight of the layer.
Inner layers sometimes employ a "copper pour" technique. Copper pour is commonly used to create a power plane or a ground plane. Another benefit of using a copper pour is to reduce the amount of chemistry (etchant) used during manufacturing (which is better for the environment) as well as helping the layer to layer bonding process.
Inner layers may be transmitted for fabrication with either a positive polarity or a negative polarity. It is important that the polarity of the layer be noted during the ordering process in the absence of a polarity distinguishable feature (i.e. thermal connection).
NOTE: For plated internal layers (buried vias) or other non-traditional internal layer processing, please use Sunstone Custom Quote.