A method of forming a semiconductor structure includes forming a first redistribution structure including a first conductive pattern. The method further includes placing a die over the first redistribution structure. The method further includes disposing a molding material over the first redistribution structure to surround the die. The method further includes removing a portion of the molding material to form an opening. The method further includes disposing a dielectric material into the opening to form a dielectric member. The method further includes forming a second redistribution structure over the molding material and the dielectric member, wherein the second redistribution structure includes an antenna structure over the dielectric member and electrically connected to the die.