A solid state drive (SSD) device, including a substrate; a first buffer chip disposed on the substrate; a second buffer chip disposed on the first buffer chip; a plurality of first nonvolatile memory chips connected to the second buffer chip through wire bonding; a controller configured to transmit a control signal to the plurality of first nonvolatile memory chips through a first channel; and a first redistribution layer disposed in the substrate and configured to electrically connect the first channel to the first buffer chip, wherein the first buffer chip is connected to the first redistribution layer through flip chip bonding, and the second buffer chip is connected to the first redistribution layer through a first wire.