Source/drain contact at tight cell boundary
Embodiments of present invention provide a semiconductor structure. The semiconductor structure includes a semiconductor wafer having a first transistor and a second transistor; a first source/drain (S/D) contact of the first transistor; a second S/D contact of the second transistor; and a cut region between the first S/D contact and the second S/D contact, wherein the cut region includes a liner of a first dielectric material and a filler of a second dielectric material that is different from the first dielectric material, the liner lining at least a part of the first S/D contact and a part of the second S/D contact, and the filler being directly adjacent to the liner and between the first S/D contact and the second S/D contact. A method of manufacturing the semiconductor structure is also provided.
1 . A semiconductor structure comprising:
a semiconductor wafer having a first transistor and a second transistor;
a first source/drain (S/D) contact of the first transistor;
a second S/D contact of the second transistor; and
a cut region between the first S/D contact and the second S/D contact,
wherein the cut region includes a liner of a first dielectric material and a filler of a second dielectric material that is different from the first dielectric material, the liner lining at least a part of the first S/D contact and a part of the second S/D contact, the filler being in a solid state and directly adjacent to the liner and between the first S/D contact and the second S/D contact.
2 . The semiconductor structure of claim 1 , wherein the first S/D contact connects a first S/D region of the first transistor to a back-end-of-line (BEOL) interconnect at a frontside of the semiconductor wafer through a via contact.
3 . The semiconductor structure of claim 1 , wherein the second S/D contact connects a second S/D region of the second transistor to a backside power distribution network (BSPDN) through a via to backside-power-rail (VBPR), the VBPR extending through a shallow trench isolation (STI) layer.
4 . The semiconductor structure of claim 2 , wherein the via contact connects to the first S/D contact of the first transistor through a metal extension, the metal extension being at an edge of the first S/D contact and covering partially both a top and a sidewall of the first S/D contact.
5 . The semiconductor structure of claim 4 , wherein a vertical portion of the metal extension is directly between the first S/D contact and the filler.
6 . The semiconductor structure of claim 1 , wherein the cut region is a first cut region, further comprising a second cut region, the second cut region being between a second S/D contact of the first transistor and a first S/D contact of the second transistor, wherein the first cut region and the second cut region are not aligned in a straight line.
7 . A method of forming a semiconductor structure comprising:
forming an initial source/drain (S/D) contact connecting to both a first S/D region of a first transistor and a second S/D region of a second transistor;
creating a cut region, the cut region cutting the initial S/D contact into a first S/D contact connecting to the first S/D region of the first transistor and a second S/D contact connecting to the second S/D region of the second transistor;
lining the cut region with a liner of a first dielectric material;
filling the cut region with a filler of a second dielectric material, the filler being in a solid state and directly adjacent to the liner;
removing a portion of the liner of the first dielectric material, selective to the filler of the second dielectric material, at an edge of the first S/D contact;
forming a metal extension at the edge of the first S/D contact; and
forming a via contact connecting to the metal extension.
8 . The method of claim 7 , wherein removing the portion of the liner of the first dielectric material creates an opening that exposes partially a top and a sidewall of the first S/D contact at the edge thereof.
9 . The method of claim 8 , wherein forming the metal extension comprises filling the opening with a conductive material to cover partially the top and the sidewall of the first S/D contact.
10 . The method of claim 7 , wherein the initial S/D contact connects to a via to backside-power-rail (VBPR) between the first transistor and the second transistor, and wherein creating the cut region creates the first S/D contact that is isolated from the VBPR and the second S/D contact that is connected to the VBPR.
11 . The method of claim 10 , further comprising forming a backside power distribution network (BSPDN) connecting to the VBPR that is connected to the second S/D contact of the second transistor.
12 . The method of claim 7 , further comprising forming an interconnect of a back-end-of-line (BEOL) connecting to the via contact that is connected to the first S/D contact, through the metal extension, of the first transistor.
13 . The method of claim 7 , wherein the cut region extends to an area between a second S/D contact of the first transistor and a first S/D contact of the second transistor in a non-straight manner.
14 . A semiconductor structure comprising:
a semiconductor wafer having a first transistor and a second transistor;
a first and a second source/drain (S/D) contact of the first transistor;
a first and a second S/D contact of the second transistor;
a first cut region between the first S/D contact of the first transistor and the second S/D contact of the second transistor; and
a second cut region between the second S/D contact of the first transistor and the first S/D contact of the second transistor,
wherein the second cut region is parallel to the first cut region but not in a straight extension of the first cut region.
15 . The semiconductor structure of claim 14 , wherein the first cut region includes a liner of a first dielectric material and a filler of a second dielectric material, the second dielectric material being different from the first dielectric material, the liner lining at least a part of the first S/D contact of the first transistor and a part of the second S/D contact of the second transistor, the filler being directly adjacent to the liner and between the first S/D contact of the first transistor and the second S/D contact of the second transistor.
16 . The semiconductor structure of claim 15 , wherein the first S/D contact of the first transistor connects a first S/D region of the first transistor to a back-end-of-line (BEOL) interconnect at a frontside of the semiconductor wafer through a via contact.
17 . The semiconductor structure of claim 16 , wherein the via contact connects to the first S/D contact of the first transistor through a metal extension, the metal extension being at an edge of the first S/D contact of the first transistor and covering partially a top and a sidewall of the first S/D contact of the first transistor.
18 . The semiconductor structure of claim 17 , wherein a vertical portion of the metal extension is directly between the first S/D contact of the first transistor and the filler.
19 . The semiconductor structure of claim 14 , wherein the second S/D contact of the second transistor connects a second S/D region of the second transistor to a backside power distribution network (BSPDN) through a via to backside-power-rail (VBPR), the VBPR extending through a shallow trench isolation (STI) layer.
20 . The semiconductor structure of claim 14 , wherein the first cut region and the second cut region are connected by a third cut region in a non-straight manner.