A method includes encapsulating a device die in an encapsulating material, planarizing the device die and the encapsulating material, and forming a first plurality of conductive features electrically coupling to the device die. The step of forming the first plurality of conductive features includes a deposition-and-etching process, which includes depositing a blanket copper-containing layer, forming a patterned photo resist over the blanket copper-containing layer, and etching the blanket copper-containing layer to transfer patterns of the patterned photo resist into the blanket copper-containing layer.