Semiconductor structure and fabrication method thereof
A semiconductor structure includes a substrate; a first dielectric layer on the substrate; an etch stop layer on the first dielectric layer; a second dielectric layer on the etch stop layer; a first conductor and a second conductor in the second dielectric layer, an air gap in the second dielectric layer and between the first conductor and the second conductor; and a low-polarity dielectric layer on a sidewall surface of the second dielectric layer within the air gap.
1 . A semiconductor structure, comprising:
a substrate;
a first dielectric layer on the substrate;
an etch stop layer on the first dielectric layer;
a second dielectric layer on the etch stop layer;
a first conductor and a second conductor in the second dielectric layer;
an air gap in the second dielectric layer and between the first conductor and the second conductor;
a first low-polarity dielectric layer on a sidewall surface of the second dielectric layer within the air gap;
a second low-polarity dielectric layer disposed around the first conductor; and
a third low-polarity dielectric layer disposed around the second conductor.
2 . The semiconductor structure according to claim 1 , wherein the first dielectric layer is a silicon oxide layer and the second dielectric layer is a low-dielectric constant (low-k) material layer.
3 . The semiconductor structure according to claim 2 , wherein the low-k material layer comprises organo-silicate glass (OSG) based low-k dielectric layer.
4 . The semiconductor structure according to claim 1 , wherein the first low-polarity dielectric layer is a silylated surface layer.
5 . The semiconductor structure according to claim 1 , wherein the second and third low-polarity dielectric layers are silylated surface layers.
6 . The semiconductor structure according to claim 1 , wherein the second low-polarity dielectric layer is in direct contact with the first conductor, and the third low-polarity dielectric layer is in direct contact with the second conductor.
7 . The semiconductor structure according to claim 1 , wherein the first conductor and the second conductor comprise copper.
8 . The semiconductor structure according to claim 1 , wherein the air gap extends into the etch stop layer and the first dielectric layer.
9 . The semiconductor structure according to claim 8 further comprising:
a silylated oxide surface layer on a sidewall surface of the first dielectric layer.