Trench formation for dielectric filled cut region
A method for forming a gate cut region includes forming a tapered profile gate line trench through a hard mask, a dummy layer and a dummy dielectric formed on a substrate, forming a dummy gate dielectric and a dummy gate conductor in the trench and planarizing a top surface to reach the hard mask. The dummy gate conductor is patterned to form a cut trench in a cut region. The dummy gate conductor is recessed, and the cut trench is filled with a first dielectric material. The dummy layer is removed and spacers are formed. A gate line is opened up and the dummy gate conductor is removed from the gate line trench. A gate dielectric and conductor are deposited, and a gate cap layer provides a second dielectric that is coupled to the first dielectric material in the cut trench to form a cut last structure.
1. A device having a gate cut region, comprising:
a tapered profile gate line formed on a substrate, the tapered profile gate line including a gate dielectric and a gate metal formed within the tapered profile and spacers formed on sidewalls of the tapered profile gate line;
source and drain regions formed adjacent to the spacers; and
a cut last structure formed in a mid-portion along the tapered profile gate line in a cut region, the cut region including a first dielectric material formed on a shallow trench isolation region in the substrate and a second dielectric material forming a gate cap layer and forming vertical interface regions between the gate cap layer and the first dielectric material.
2. The device as recited in claim 1 , wherein the tapered profile gate line includes a gradual tapered profile formed by using a lithography, etch, lithography, etch (LELE) process.
3. The device as recited in claim 1 , wherein the first dielectric and the second dielectric include silicon nitride.
4. The device as recited in claim 1 , further comprising an interlevel dielectric layer (ILD) formed over the cap layer, and opened up to form contacts therein.
5. The device as recited in claim 4 , wherein the contacts are formed over the vertical interface regions between the gate cap layer and the first dielectric material.
6. The device as recited in claim 1 , wherein the tapered profile gate line prevents pinch-off for metal layers deposited therein.
7. The device as recited in claim 1 , wherein the tapered profile includes a larger taper dimension as distance increases from the substrate.