Manufacturing method of a semiconductor memory device

A method of manufacturing a semiconductor memory device, the method comprising:

• processing a first substrate, wherein processing the first substrate comprises:
• disposing a peripheral circuit and a first conductive contact pattern coupled to the peripheral circuit over a first region of the first substrate;
• embedding a sacrificial material in a second region of the first substrate;
• and
• disposing a first align mark over the sacrificial material;
• processing a second substrate, wherein processing the second substrate comprises disposing a second align mark, a memory cell array, and a second conductive contact pattern coupled to the memory cell array over the second substrate;
• orientating the first substrate and the second substrate such that the first conductive contact pattern and the second conductive contact pattern face each other;
• and
• coupling the first conductive contact pattern to the second conductive contact pattern by checking alignment of the first align mark with the second align mark.