What is Inner Layer
Inner layer is is the copper layers positioned between the outer layers of a multilayer circuit board. These inner layers are typically made up of laminates and copper of varying thicknesses, depending on the desired build-up of the board.
The inner layers can contain conductive patterns or ground planes, which contribute to the PCB’s overall electrical connectivity and performance. These patterns and planes allow for the routing of traces, components, and connections, enabling more complex circuit designs and higher component density.
Vias are used to ensure proper connectivity between the inner and outer layers. Vias are small holes that are drilled through the layers and filled with conductive material, allowing for electrical connections. Depending on whether the vias exclusively connect the inner layers or extend to the outer layers, they can be classified as blind vias or buried vias.