US Patent 7745933 Circuit structure and process thereof

A circuit structure has a first dielectric layer, a first circuit pattern embedded in the first dielectric layer and having a first via pad, a first conductive via passing through the first dielectric layer and connecting to the first via pad, and an independent via pad disposed on a surface of the first dielectric layer away from the first via pad and connecting to one end of the first conductive via. The circuit structure further has a second dielectric layer disposed over the surface of the first dielectric layer where the independent via pad is disposed, a second conductive via passing through the second dielectric layer and connecting to the independent via pad, and a second circuit pattern embedded in the second dielectric layer, located at a surface thereof away from the independent via pad, and having a second via pad connected to the second conductive via.