Method for forming storage node contact plug of DRAM (dynamic random access memory)

A method for fabricating a semiconductor device comprising:

• forming first, second, third, and fourth insulating layers on an overall surface of a semiconductor substrate having a plurality of buried contact plugs;
• etching the fourth, third, second, and first insulating layers down to a top surface of the buried contact plugs to form first contact openings on the buried contact plugs;
• forming a photoresist pattern on the fourth insulating layer and the first contact openings;
• etching the fourth and third insulating layers by using the photoresist pattern as a mask, to form second contact openings;
• and
• filling the first and second contact openings with a conductive material.

A method for fabricating a semiconductor device comprising:

• forming one or more insulating layers on a semiconductor substrate having a buried contact plug;
• forming a photoresist pattern on a top surface of the insulating layers;
• etching the insulating layers, using the photoresist pattern as a mask, to form a first contact opening;
• etching the insulating layers down to the buried contact plug to form a second contact opening on the buried contact plug;
• and
• filling the first and second contact openings with a conductive material.

A semiconductor device comprising:

• a semiconductor substrate comprising a buried contact plug and having one or more insulating layers formed thereon;
• a conductive plug formed in a first contact opening in the insulating layers, the conductive plug and the first contact opening extending down to the buried contact plug, the conductive plug containing a first conductive material;
• and
• a bit line portion formed in a second contact opening in the insulating layers, the bit line portion and the second contact opening extending partially into the insulating layers, the bit line portion containing the first conductive material.