A method to form a vertical interconnect advantageous for high-density
semiconductor devices. A conductive etch stop layer, preferably of cobalt
silicide, is formed. The etch stop layer may be in the form of patterned
lines or wires. A layer of contact material is formed on and in contact
with the etch stop layer. The layer of contact material is patterned to
form posts. Dielectric is deposited over and between the posts, then the
dielectric planarized to expose the tops of the posts. The posts can
serve as vertical interconnects which electrically connect a next
conductive layer formed on and in contact with the vertical interconnects
with the underlying etch stop layer. The patterned dimension of vertical
interconnects formed according to the present invention can be
substantially the same as the minimum feature size, even at very small
minimum feature size.