Miniaturized contact in semiconductor substrate and method for forming the same

A method for forming a miniaturized contact in a semiconductor substrate, said substrate including:

• a diffused layer formed at a surface of said semiconductor substrate;
• an interlayer film disposed on said semiconductor substrate for covering said diffused layer;
• a plurality of lower interconnections buried within said interlayer film;
• and
• an upper interconnection disposed on said interlayer film,
• wherein said method comprising the steps of:
• opening a contact hole passing through said interlayer film for connecting said diffused layer with said upper interconnection, said contact hole having an aperture diameter equivalent to a space interval between said lower interconnections;
• forming a first conductor for covering said interlayer film, said first conductor filling said contact hole;
• etchback said first conductor for remaining a part of said first conductor only from the bottom of said contact hole to a height lower than that of said lower interconnections, said part of said first conductor forming a first buried conductor;
• forming a side-wall insulator on a side-wall of said contact hole above said first buried conductor after forming said first buried conductor;
• forming a second conductor for covering said interlayer film, said second conductor contacting with said first buried conductor;
• etchback said second conductor for remaining a part of said second conductor only within said contact hole, said part of said second conductor forming a second buried conductor;
• and
• forming an upper interconnection for connecting with said second buried conductor.