A device includes a substrate, a first conductive layer on the substrate, a first conductive via, and further conductive layers and conductive vias between the first conductive via and the substrate. The first conductive via is between the substrate and the first conductive layer, and is electrically connected to the first conductive layer. The first conductive via extends through at least two dielectric layers, and has thickness greater than about 8 kilo-Angstroms. An inductor having high quality factor is formed in the first conductive layer and also includes the first conductive via.