Methods of forming integrated circuit chips having vertically extended through-substrate vias therein and chips formed thereby
Methods of forming an integrated circuit device include forming an interlayer dielectric layer on a first surface of a semiconductor substrate and then forming an interconnect hole that extends through the interlayer dielectric layer and into the semiconductor substrate. A first sidewall spacer layer is formed on a sidewall of the interconnect hole. The semiconductor substrate at a bottom of the interconnect hole is isotropically etched to define an undercut recess in the semiconductor substrate. This etching step is performed using the first sidewall spacer layer as an etching mask. The interconnect hole and the uncut recess are then filled with a through-via electrode. A second surface of the semiconductor substrate is removed for a sufficient duration to expose the uncut recess containing the through-via electrode.
1. A method of forming an integrated circuit device, comprising:
forming an interlayer dielectric layer on a first surface of a semiconductor substrate;
forming an interconnect hole that extends through the interlayer dielectric layer and into the semiconductor substrate;
forming a first sidewall spacer layer on a sidewall of the interconnect hole;
etching the semiconductor substrate at a bottom of the interconnect hole to thereby define an undercut recess in the semiconductor substrate;
filling the interconnect hole and the undercut recess with a through-via electrode after removing the first sidewall spacer layer from a sidewall of the interconnect hole; and
removing a second surface of the semiconductor substrate to expose the through-via electrode.
2. The method claim 1 , wherein said etching comprises isotropically etching the semiconductor substrate at a bottom of the interconnect hole using the first sidewall spacer layer as an etching mask.
3. The method claim 1 , wherein said removing the first sidewall spacer layer is followed by a step of lining a sidewall of the interconnect hole and the undercut recess with a second sidewall spacer layer.
4. The method claim 1 , wherein said removing comprises removing the second surface of the semiconductor substrate and the second sidewall spacer layer to expose the through-via electrode.
5. The method claim 1 , wherein filling the interconnect hole and the undercut recess with a through-via electrode is followed by forming an intermetal dielectric layer on an upper surface of said interlayer dielectric layer, said intermetal dielectric layer having a multi-level metal interconnect therein that contacts the through-via electrode.