Low-K dielectric interconnect systems
View Patent ↗A method of fabricating a semiconductor device includes forming a low-k dielectric layer over a substrate and depositing a cap layer over the low-k dielectric layer. A treatment process is performed to the cap layer. After the treatment process to the cap layer is performed, the low-k dielectric layer is etched to form a plurality of trenches using the cap layer as an etching mask.
1. A method of fabricating a semiconductor device, comprising:
forming a low-k dielectric layer;
depositing a cap layer over the low-k dielectric layer, the depositing the cap layer includes:
forming a bottom cap layer over the low-k dielectric layer; and
forming a top cap layer of the cap layer over the bottom cap layer, wherein the top cap layer includes a metal;
etching the low-k dielectric layer to form a first trench and a second trench using the cap layer as an etching mask.
2. The method of claim 1 , wherein the bottom cap layer includes silicon oxycarbide.
3. The method of claim 1 , further comprising:
prior to the etching the low-k dielectric layer, performing a treatment process to the cap layer.
4. The method of claim 1 , further comprising:
prior to the etching the low-k dielectric layer, performing a treatment process to the cap layer;
wherein the cap layer induces a first stress on the low-k dielectric layer prior to the performing the treatment process,
wherein the cap layer induces a second stress different from the first stress on the low-k dielectric layer after the performing the treatment process, and
wherein an absolute value of the second stress is less than about 50% of an absolute value of the first stress.
5. The method of claim 4 , further comprising:
prior to the performing the depositing the cap layer, performing a second treatment process to the low-k dielectric layer to change a dielectric constant of the low-k dielectric layer.
6. The method of claim 5 , wherein during the performing the treatment process, the dielectric constant of the low-k dielectric layer remains substantially the same.
7. The method of claim 6 , further comprising:
after the etching the low-k dielectric layer to form the first and second trenches, irradiating sidewalls and bottoms of the first and second trenches with a third radiation to change the dielectric constant of the low-k dielectric layer.
8. A method, comprising:
providing a layout of a connective layer including a first pattern having a first width in a first direction and a second pattern disposed at a distance from the first pattern in the first direction;
forming a low-k dielectric layer having a height over a substrate;
depositing a cap layer over the low-k dielectric layer;
irradiating a top surface of the cap layer with a first radiation;
patterning the cap layer to form a first opening associated with the first pattern and a second opening associated with the second pattern; and
performing an etching process to transfer the first opening to a first trench in the low-k dielectric layer and transfer the second opening to a second trench in the low-k dielectric layer.
9. The method of claim 8 ,
wherein a ratio between the height and the distance is greater than a pre-defined height-to-width aspect ratio threshold; and
wherein the pre-defined height-to-width aspect ratio threshold is greater than about 5:1.
10. The method of claim 9 , wherein after the performing the etching process, the first trench has a second width at a top surface of the low-k dielectric layer, and
wherein the first width and the second width are substantially the same.
11. The method of claim 10 , wherein a difference between the first width and the second width is less than about 10% of the first width.
12. The method of claim 11 , further comprising:
prior to the depositing the cap layer, irradiating the low-k dielectric layer with a second radiation.
13. The method of claim 12 , wherein the second radiation has a second wavelength different from a first wavelength of the first radiation.
14. The method of claim 13 , further comprising:
after the etching the low-k dielectric layer to form the first trench and the second trench, irradiating sidewalls and bottoms of the first trench and the second trench with a third radiation to change a dielectric constant of the low-k dielectric layer.
15. The method of claim 14 , wherein the third radiation has a third wavelength different from the first wavelength of the first radiation.
16. A method, comprising:
forming a low-k dielectric layer over a substrate;
forming a lower cap layer over the low-k dielectric layer;
forming an upper cap layer over the lower cap layer; and
performing a first treatment process to the cap layer,
wherein the lower cap layer has a first hardness prior to the first treatment process and a second hardness greater than the first hardness after the first treatment process; and
wherein during the first treatment process, a dielectric constant of the low-k dielectric layer remains substantially the same; and
etching the low-k dielectric layer to form a plurality of trenches using the cap layer as an etching mask.
17. The method of claim 16 , further comprising:
prior to the performing the depositing the cap layer, performing a second treatment process to the low-k dielectric layer to change the dielectric constant of the low-k dielectric layer.
18. The method of claim 16 , wherein the performing the first treatment process includes:
irradiating an ultraviolet (UV) radiation on the cap layer.
19. The method of claim 16 , wherein the lower cap layer includes silicon oxycarbide.
20. The method of claim 16 , wherein the upper cap layer includes a metal.