Conductive structure in semiconductor structure and method for forming the same

1 . A semiconductor structure, comprising:

an aluminum-containing layer;

an etch stop layer formed over the aluminum-containing layer;

a carbon-containing dielectric layer formed over the etch stop layer, wherein an atomic concentration of carbon in the carbon-containing dielectric layer is in a range from about 15% to about 35%;

a metal line formed in an upper portion of the carbon-containing dielectric layer, wherein the metal line has a top surface and a first sidewall connected to the top surface;

a conductive via formed in a lower portion of the carbon-containing dielectric layer and through the etch stop layer and the aluminum-containing layer, wherein the conductive via has a second sidewall adjoining the first sidewall of the metal line; and

a barrier layer interposing the first sidewall of the metal line and carbon-containing dielectric layer and interposing the second sidewall of the conductive via and the carbon-containing dielectric layer,

wherein the metal line, the conductive via, and the barrier layer comprise a same dopant.

2 . The semiconductor structure as claimed in claim 1 , wherein a hardness of the carbon-containing dielectric layer is in a range from about 2 Gpa to about 3 Gpa.

3 . The semiconductor structure as claimed in claim 1 , wherein a top surface of the carbon-containing dielectric layer is substantially level with the top surface of the metal line.

4 . The semiconductor structure as claimed in claim 3 , wherein a bottom surface of the aluminum-containing layer is substantially level with a bottom surface of the barrier layer.

5 . The semiconductor structure as claimed in claim 1 , wherein the dopant is Mn.

6 . A semiconductor structure, comprising:

a first aluminum-containing layer, a first etch stop layer, and a first carbon-containing dielectric layer sequentially stacked in a first direction over a substrate;

a first metal line formed through an upper portion of the first carbon-containing dielectric layer and longitudinally oriented in a second direction that is different from the first direction, wherein the first metal line comprises a periphery region and a middle region surrounded by the periphery region, an atomic concentration of first dopants in the periphery region is greater than an atomic concentration of the first dopants in the middle region;

a first conductive via formed through a lower portion of the first carbon-containing dielectric layer, the first etch stop layer, and the first aluminum-containing layer; and

a first barrier layer covering a slope sidewall of the first carbon-containing dielectric layer in a cross-sectional view along a third direction that is different from the first direction and the second direction.

7 . The semiconductor structure as claimed in claim 6 , further comprising:

a second aluminum-containing layer formed over the first metal line,

wherein a first end of the first barrier layer adjoins a bottom surface of the second aluminum-containing layer and a second end of the first barrier layer is substantially level with a bottom surface of the first aluminum-containing layer in the cross-sectional view along the third direction.

8 . The semiconductor structure as claimed in claim 7 , further comprising:

a second etch stop layer and a second carbon-containing dielectric layer formed over the second aluminum-containing layer;

a second metal line formed through an upper portion of the second carbon-containing dielectric layer;

a second conductive via formed through a lower portion of the second carbon-containing dielectric layer, the second etch stop layer, and the second aluminum-containing layer; and

a second barrier layer surrounding the second metal line and the second conductive via,

wherein the second barrier layer is in contact with the periphery region of the first metal line.

9 . The semiconductor structure as claimed in claim 6 , wherein the first conductive via has a first dimension in the second direction, and the first metal line has a second dimension in the second direction that is greater than the first dimension.

10 . The semiconductor structure as claimed in claim 6 , wherein the first carbon-containing dielectric layer has a third dimension in the first direction, the first etch stop layer has a fourth dimension in the first direction, the first aluminum-containing layer has a fifth dimension in the first direction, the third dimension is greater than the fourth dimension, and the fourth dimension is greater than the fifth dimension.

11 . The semiconductor structure as claimed in claim 10 , wherein a sum of the third dimension, the fourth dimension, and the fifth dimension is substantially equal to a distance between a top surface of the first metal line to a bottom surface of the first barrier layer in the first direction.

12 . The semiconductor structure as claimed in claim 7 , wherein a top portion of the periphery region of the first metal line is attached to the bottom surface of the second aluminum-containing layer.

13 . A method for manufacturing a semiconductor structure, comprising:

forming an aluminum-containing layer;

forming an etch stop layer over the aluminum-containing layer;

forming a carbon-containing dielectric layer over the etch stop layer, wherein an atomic concentration of carbon in the carbon-containing dielectric layer is greater than 15%;

forming a via opening and a line trench in the carbon-containing dielectric layer, wherein the via opening passes through the etch stop layer and partially extends into the aluminum-containing layer, so that a bottom surface of the via opening is lower than a top surface of the aluminum-containing layer while is higher than a bottom surface of the aluminum-containing layer;

etching through the aluminum-containing layer so that the via opening extends through the aluminum-containing layer; and

forming a conductive structure in the via opening and the line trench.

14 . The method for manufacturing the semiconductor structure as claimed in claim 13 , wherein forming the conductive structure in the via opening and the line trench comprises:

forming a first barrier layer over sidewalls of the via opening and the line trench by performing an atomic layer deposition process;

forming a second barrier layer over the first barrier layer by performing a physical vapor deposition process;

forming a conductive layer over the second barrier layer, wherein the conductive layer is doped with dopants; and

polishing the first barrier layer, the second barrier layer, and the conductive layer to form the conductive structure.

15 . The method for manufacturing the semiconductor structure as claimed in claim 14 , wherein forming the conductive structure in the via opening and the line trench comprises:

diffusing the dopants so that a concentration of the dopants in a first region of the conductive structure is greater than a concentration of the dopants in a second region of the conductive structure.

16 . The method for manufacturing the semiconductor structure as claimed in claim 13 , further comprising:

forming a mask structure over the carbon-containing dielectric layer;

forming a first opening in the mask structure and longitudinally oriented in a first direction, wherein the first opening has a first dimension in the first direction;

forming a second opening in the carbon-containing dielectric layer overlapping the first opening after forming the first opening, wherein the second opening has a second dimension in the first direction that is smaller than the first dimension; and

etching the carbon-containing dielectric layer through the first opening and the second opening to form the line trench and the via opening.

17 . The method for manufacturing the semiconductor structure as claimed in claim 13 , further comprising

forming the via opening through the carbon-containing dielectric layer, wherein the via opening has a first dimension in a first direction;

forming a blocking structure in a bottom portion of the via opening;

etching the carbon-containing dielectric layer to form the line trench in the carbon-containing dielectric layer after forming the blocking structure, wherein the line trench has a second dimension in the first direction that is greater than the first dimension; and

removing the blocking structure.

18 . The method for manufacturing the semiconductor structure as claimed in claim 17 , wherein the blocking structure is partially etched when etching the carbon-containing dielectric layer to form the line trench.

19 . The method for manufacturing the semiconductor structure as claimed in claim 15 , wherein the second region of the conductive structure is surrounded by the first region of the conductive structure.

20 . The method for manufacturing the semiconductor structure as claimed in claim 15 , wherein the conductive structure is doped with Mn.