Patent ID: 8264086

Claim:
A semiconductor device comprising: a first conductor having a top surface and a via recess extending from the top surface into the first conductor to form a recess of a predetermined depth, wherein the first conductor is a metal line; a dielectric layer over the first conductor; a via structure comprising a via opening filled with a conductor and having a top end and a bottom end, wherein the via opening has a tapered profile with a width of the via opening gradually increasing substantially throughout the bottom end to the top end, and wherein the via structure includes the conductor that extends into the via recess; and an additional metal line adjoining the via structure, wherein the additional metal line has a substantially flat horizontal bottom surface, wherein a sidewall of the via opening increases in height monotonically and smoothly from a bottom of the via opening to a top of the via opening, with a rounded interface region connecting the sidewall at the top of the via opening to the substantially flat horizontal bottom surface of the additional metal line.