Memory device and method for forming the same

A method, comprising:

• forming a semiconductor strip protruding over a substrate;
• forming an isolation structure over the substrate and adjacent to the semiconductor strip;
• etching the isolation structure to form a trench;
• depositing a liner in the trench;
• depositing a conductive material in the trench and over the liner;
• etching back the conductive material;
• depositing a dielectric material over the conductive material;
• and
• forming a semiconductor device over the semiconductor strip and electrically connected to the conductive material.

A method, comprising:

• forming a first metal line and a second metal line over a substrate and at a first level;
• forming a first transistor and a second transistor over the substrate and at a second level higher than the first level, wherein the first metal line is electrically connected to the first transistor, and the second metal line is electrically connected to the second transistor;
• forming a third transistor over the substrate and at a third level higher than the second level, wherein the third transistor is electrically connected to the first transistor and the second transistor, and
• forming a third metal line over the substrate and at a fourth level higher than the third level, wherein the third metal line is electrically connected to the second transistor wherein the first metal line serves as a power line, the second metal line serves as a bit line, and the third metal line serves as a word line.