Method and device for a FinFET
A method of forming a semiconductor device includes providing a semiconductor substrate. The semiconductor substrate includes a plurality of fins formed thereon, a stress layer formed on the top surface of each of the fins, and a plurality of strip-shaped gate structures formed above the stress layers. The method further includes forming a contact hole etch stop layer. The method further includes forming a first interlayer dielectric layer to fill the gaps between adjacent fins. The first interlayer dielectric layer includes filling voids formed therein. The method further includes back etching the first interlayer dielectric layer to cause the top surface of the first interlayer dielectric layer to be just above the filling voids. The method further includes forming a barrier liner layer over the first interlayer dielectric layer, and forming a second interlayer dielectric layer over the barrier liner layer and the contact hole etch stop layer.
1. A method of forming a semiconductor device, the method comprising:
providing a semiconductor substrate, the semiconductor substrate including a plurality of fins formed thereon, each of the fins having a stress layer formed on a top surface thereof, and a plurality of strip-shaped gate structures formed above the stress layer of each of the fins, each gate structure extending in a direction substantially perpendicular to a direction of the fins;
forming a contact hole etch stop layer covering a surface of the semiconductor substrate, sidewalls of the fins, and a top surface and sidewalls of the stress layer of each of the fins;
forming a first interlayer dielectric layer filling gaps between adjacent fins, a top surface of the first interlayer dielectric layer being above the top surface of the stress layer of each of the fins, the first interlayer dielectric layer including filling voids formed therein;
back etching the first interlayer dielectric layer causing a top surface of a remaining first interlayer dielectric layer to be below the top surface of the stress layer of each of the fins but above the filling voids;
forming a barrier liner layer on the top surface of the remaining first interlayer dielectric layer; and
forming a second interlayer dielectric layer on the barrier liner layer and the contact hole etch stop layer.
2. The method of claim 1 , wherein the stress layer comprises SiGe or SiC.
3. The method of claim 1 , further comprising, before forming the first interlayer dielectric layer, forming a high aspect ratio pad (HARP) layer over the contact hole etch stop layer.
4. The method of claim 3 , wherein the HARP layer comprises an oxide layer formed by chemical vapor deposition or atomic layer deposition.
5. The method of claim 3 , further comprising, before forming the first interlayer dielectric layer, back etching the HARP layer using SiCoNi dry etching, or treating the first interlayer dielectric layer using ozone.
6. The method of claim 1 , wherein the barrier liner layer comprises oxide or nitride.
7. The method of claim 1 , wherein the barrier liner layer has a thickness ranging from about 2 nm to about 15 nm.
8. The method of claim 1 , wherein forming the first interlayer dielectric layer or the second interlayer dielectric layer comprises:
depositing a flowable dielectric material;
curing the flowable dielectric material; and
annealing the flowable dielectric material.
9. The method of claim 8 , wherein the curing is performed using deionized water and ozone.
10. The method of claim 8 , wherein the annealing comprises vapor annealing or dry annealing, or a combination thereof.