Semiconductor structure having air gap dielectric and method of preparing the same
The present disclosure provides a semiconductor structure including a base layer, a first conductive line disposed on the base layer, a first dielectric pillar disposed on the base layer, a second dielectric pillar disposed on the base layer, a first liner, and a second liner. The first conductive line is disposed between the first dielectric pillar and the second dielectric pillar. The first liner encloses a first air gap, and is disposed between the first dielectric pillar and the first conductive line. The second liner encloses a second air gap, and is disposed between the second dielectric pillar and the first conductive line.
1 . A semiconductor structure, comprising:
a base layer;
a first conductive line disposed on the base layer;
a first dielectric pillar disposed on the base layer;
a second dielectric pillar disposed on the base layer, wherein the first conductive line is disposed between the first dielectric pillar and the second dielectric pillar;
a first liner, enclosing a first air gap, disposed between the first dielectric pillar and the first conductive line; and
a second liner, enclosing a second air gap, disposed between the second dielectric pillar and the first conductive line, wherein each of the first and second liner is a monolithic structure and has a uniform thickness.
2 . The semiconductor structure of claim 1 , further comprising:
a sealing layer disposed over and in contact with the first conductive line, the first dielectric pillar, the second dielectric pillar, the first liner, and the second liner.
3 . The semiconductor structure of claim 1 , wherein the first liner comprises:
a horizontal portion in contact with the base layer;
a vertical portion in contact with the first conductive line; and
an arced portion in contact with the first dielectric pillar, wherein the arced portion connects the horizontal portion and the vertical portion.
4 . The semiconductor structure of claim 1 , wherein the first liner is made by an energy removable material.
5 . The semiconductor structure of claim 1 , wherein the first liner has a uniform thickness.
6 . The semiconductor structure of claim 1 , wherein a top corner of the first air gap is lower than a top end of the first dielectric pillar.
7 . The semiconductor structure of claim 1 , wherein a top corner of the first air gap is higher than a top end of the first dielectric pillar.
8 . The semiconductor structure of claim 1 , wherein a top corner of the first air gap is leveled with a top end of the first dielectric pillar.
9 . The semiconductor structure of claim 1 , wherein the first liner and the second liner are mirror symmetric.
10 . The semiconductor structure of claim 1 , wherein the first air gap has a rectangular contour.
11 . The semiconductor structure of claim 1 , wherein the first air gap has a triangular contour.
12 . The semiconductor structure of claim 1 , wherein a top width of the second dielectric pillar is greater than a bottom width of the second dielectric pillar.
13 . The semiconductor structure of claim 12 , wherein a top width of the first dielectric pillar is greater than the top width of the second dielectric pillar.
14 . The semiconductor structure of claim 1 , wherein a bottom width of the first liner is greater than a top width of the first liner.
15 . The semiconductor structure of claim 1 , further comprising:
a first plug disposed in the base layer, wherein the first plug is in contact with the first conductive line.
16 . The semiconductor structure of claim 15 , wherein a width of the first plug is less than a width of the first conductive line.
17 . The semiconductor structure of claim 1 , further comprising:
a second conductive line disposed on the base layer;
a third dielectric pillar disposed on the base layer;
a third line, enclosing a third air gap, disposed between the second dielectric pillar and the second conductive line; and
a fourth line, enclosing a fourth air gap, disposed between the third dielectric pillar and the second conductive line.
18 . The semiconductor structure of claim 17 , further comprising:
a second plug disposed in the base layer, wherein the second plug is in contact with the second conductive line.
19 . The semiconductor structure of claim 17 , wherein a top width of the third dielectric pillar is greater than a top width of the second dielectric pillar.