US Patent 11417672 Semiconductor memory device and manufacturing method thereof

There are provided a semiconductor memory device and a manufacturing method thereof. The manufacturing method of the semiconductor memory device includes: forming a preliminary memory cell array that includes a gate stack structure and a channel structure, wherein the gate stack structure includes interlayer insulating layers and conductive patterns, alternately stacked on a first substrate, and wherein the channel structure has a first end portion that penetrates the gate stack structure and extends into the first substrate; forming a common source line to be in contact with a second end portion of the channel structure, the common source line formed on a first surface of the gate stack structure; removing the first substrate; and forming a bit line connected to the first end portion of the channel structure on a second surface of the gate stack structure that is opposite of the first surface of the gate stack structure.