A method includes encapsulating a first device die and a second device die in an encapsulating material, forming redistribution lines over and electrically coupling to the first device die and the second device die, and bonding a bridge die over the redistribution lines to form a package, with the package including the first device die, the second device die, and the bridge die. The bridge die electrically inter-couples the first device die and the second device die. The first device die, the second device die, and the bridge die are supported with a dummy support die.