METHOD OF FORMING METAL CONTACT OPENING

摘要

The width of a metal contact opening is formed to be smaller than the minimum feature size of a photolithographically-defined opening. The method forms the metal contact opening by first etching the fourth layer of a multilayered hard mask structure to have a number of trenches that expose the third layer of the multilayered hard mask structure. Following this, the third, second, and first layers of the multilayered hard mask structure are selectively etched to expose uncovered regions on the top surface of an isolation layer that touches and lies over a source region and a drain region. The uncovered regions on the top surface of the isolation layer are then etched to form the metal contact openings.