Interconnect structure having subtractive etch feature and damascene feature
View Patent ↗Methods of forming an interconnect structure include depositing a first conductive material on a substrate. Aspects include subtractively etching the conductive material to form a patterned first conductive layer, and depositing a dielectric layer on interconnect structure. Aspects also include depositing a second conductive material on the dielectric layer and removing the second conductive material through the top of the second metal liner.
1. A method of forming an interconnect structure, the method comprising:
depositing a first conductive material on a substrate;
subtractively etching the first conductive material to form a subtractive etch feature having a first subtractive etch vertical wall, a second subtractive etch vertical wall, and an angle between a first vertical wall and a horizontal plane that is less than 90 degrees;
depositing a dielectric layer on a patterned first conductive layer of the interconnect structure;
patterning a trench in the dielectric layer;
depositing a second conductive material on the patterned dielectric layer; and
removing the second conductive material to the top of a second metal liner so as to form a damascene feature having a first damascene vertical wall, a second damascene vertical wall, and an angle between the first damascene vertical wall and the horizontal plane that is greater than 90 degrees.
2. The method according to claim 1 , wherein removing the second conductive material comprises polishing the interconnect structure by CMP.
3. The method according to claim 1 , wherein the first conductive material comprises a first conductive material selected from the group consisting of tungsten, copper, gold, silver, molybdenum, cobalt, aluminum, and alloys thereof.
4. The method according to claim 1 , wherein the dielectric layer comprises a dielectric material with a dielectric constant less than 4.
5. The method according to claim 1 , the method further comprising depositing a metal liner on the patterned first conductive layer.
6. The method according to claim 1 , the method further comprising depositing a second metal liner on the dielectric layer.
7. An interconnect structure comprising:
a subtractive etch feature comprising a first conductive material, the subtractive etch feature having a first subtractive etch vertical wall, a second subtractive etch vertical wall, and an angle between a first vertical wall and a horizontal plane that is less than 90 degrees;
a damascene feature comprising a second conductive material, the damascene feature having a first damascene vertical wall, a second damascene vertical wall, and an angle between the first damascene vertical wall and the horizontal plane that is greater than 90 degrees; and
a conductive via comprising the subtractive etch feature, and wherein the conductive via extends from a first interconnect layer to a second interconnect layer.
8. The interconnect structure according to claim 7 , wherein the conductive via is separated from a dielectric layer by a metal liner.
9. The interconnect structure according to claim 7 , wherein the first conductive material comprises a first conductive material selected from the group consisting of tungsten, copper, gold, silver, cobalt, aluminum, and alloys thereof.
10. The interconnect structure according to claim 7 , wherein the second conductive material comprises the first conductive material selected from the group consisting of tungsten, copper, gold, silver, cobalt, aluminum, and alloys thereof.
11. The interconnect structure according to claim 7 , wherein the first conductive material and the second conductive material are formed of the same material.
12. The interconnect structure according to claim 7 , wherein the first conductive material forms a first conductive wire having a trapezoidal shape when viewed in cross section.
13. The interconnect structure according to claim 7 , wherein the second conductive material forms a second conductive wire having a trapezoidal shape when viewed in cross section.
14. The interconnect structure according to claim 7 further comprising a dielectric layer comprising a silicon dioxide layer or a carbon containing silicon oxide layer.
15. An interconnect structure comprising:
a subtractive etch feature comprising a first conductive material, the subtractive etch feature having a first subtractive etch vertical wall, a second subtractive etch vertical wall, and an angle between a first vertical wall and a horizontal plane that is less than 90 degrees;
a damascene feature comprising a second conductive material, the damascene feature having a first damascene vertical wall, a second damascene vertical wall, and an angle between the first damascene vertical wall and the horizontal plane that is greater than 90 degrees; and
comprising a conductive via comprising the damascene feature, and wherein the conductive via extends from a first interconnect layer to a second interconnect layer.
16. The interconnect structure of claim 15 , wherein the conductive via is separated from a dielectric layer by a metal liner.