Method of fabricating a metal contact structure

A method of fabricating a contact structure of semiconductor devices, comprising the steps of:

• preparing a first conducting layer on a substrate;
• forming a first insulating layer on said substrate and said first conducting layer;
• forming a first vertical contact opening exposing a specific region of said first conducting layer, using a first mask, wherein a width of an under portion of said first vertical contact opening is the same as that of the lower portion thereof:
• depositing a dummy conducting layer on an upper surface of said first insulating layer and on the sidewalls of said first insulating layer within said first vertical contact opening, to electrically contact said dummy conducting layer with said first conducting layer;
• patterning said dummy conducting layer to form a patterned dummy conducting layer, wherein said patterned dummy conducting layer has an extending part positioned on a top surface of said first insulating layer and covers said first vertical contact opening;
• forming a second insulating layer on a top surface of said first insulating layer and on said patterned dummy conducting layer;
• etching said second insulating layer to form a second vertical contact opening, using a second mask, wherein said second mask is the same as said first mask, and further wherein a width of an upper portion of said second vertical contact opening is the same as that of the lower portion thereof;
• and
• depositing a second conducting layer on an upper surface of said second insulating layer and on the sidewalls of said second insulating layer, and on said extending part of said patterned dummy conducting layer, to form a metal contact.