Semiconductor storage device and manufacturing method thereof

The invention discloses a semiconductor storage device and a manufacturing method thereof. The manufacturing method comprises the steps of forming a plurality of bit line structures and a plurality ofstorage node contacts on a semiconductor substrate; forming a first clearance wall on the side wall of each bit line structure; forming a conductive layer to cover the bit line structures, the firstclearance walls and the storage node contacts; performing a first patterning manufacturing process on the conductive layer so as to form a plurality of strip-shaped contact structures, wherein the strip-shaped contact structures extend along a first direction and correspond to the plurality of storage node contacts respectively, the first clearance wall at a first side of each bit line structure in a second direction is exposed by the first patterning manufacturing process, and the first clearance wall at a second side of each bit line structure in the second direction is covered by the strip-shaped contact structure; and removing the first clearance walls exposed by the first patterning manufacturing process to form a plurality of first air clearance walls.