Vias are used to connect different conductor plate layer. Inside vias typically connected by solder, pins for component insertion.
Vias are divided into three kinds: direct pass from the top to the bottom of vias called Thnchole Vias (transmission through the hole); merely pass from one layer to the top of the inner layer, and did not penetrate all the layers, or from the inner layer penetrate out into the bottom of the vias called blind Vias (blind vias); vias connected to each other only two years between the inner layer without penetrating the bottom or the top level is called Buried Vias (hidden vias ).
Vias generally circular shape. There are two through-hole sizes, i.e., Hole Size (hole diameter) and drilling with the total pad Diameter (through-hole diameter), as shown in the shape and size of the vias.
