SEMICONDUCTOR MEMORY DEVICE AND MANUFACTURING METHOD THEREOF

A semiconductor memory device may include a substrate including an active region defined by an element isolation layer on the substrate; a word line crossing the active region and extending in a first direction; a bit line crossing the active region on the substrate and extending in a second direction; and a bit line contact directly connected to the bit line and the active region. A bit line contact may be between the substrate and the bit line. The bit line contact may include a lower bit line contact directly connected to the active region and an upper bit line contact on and in contact with the lower bit line contact. A width of an upper surface of the lower bit line contact in the second direction may be greater than a width of a lower surface of the upper bit line contact in the second direction. 一种半导体存储器件可以包括：衬底，包括衬底上由元件隔离层限定的有源区；字线，与有源区交叉并沿第一方向延伸；位线，在衬底上与有源区交叉并沿第二方向延伸；以及位线接触部，直接连接到位线和有源区。位线接触部可以在衬底与位线之间。位线接触部可以包括下位线接触部和上位线接触部，下位线接触部直接连接到有源区，上位线接触部在下位线接触部上并与下位线接触部接触。下位线接触部的上表面在第二方向上的宽度可以大于上位线接触部的下表面在第二