Process to pattern thick TiW metal layers using uniform and selective etching
View Patent ↗A method processes a thick TiW metal layer ( 12 ) on a dielectric layer ( 15 ), where the dielectric layer ( 15 ) has been deposited on a substrate ( 14 ), such as a silicon substrate. The method deposits the TiW metal layer ( 12 ) onto the dielectric layer ( 15 ), such as silicon dioxide or silicon nitride, and then deposits a photoresist ( 10 ) over the TiW metal layer ( 12 ). The method removes substantially all of the TiW metal layer ( 12 ) not in contact with the photoresist ( 10 ) with a uniform etch, such as not more than 80% to 90% of the deposited TiW metal layer. Then, the TiW metal layer ( 12 ) is selectively etched to the dielectric layer ( 15 ), to remove the TiW metal layer ( 12 ) faster than the dielectric layer ( 15 ), such as 2.7 times faster.
1. Method comprising:
providing a substrate;
depositing a dielectric layer on the substrate;
depositing an at least 2000 angstrom thick TiW metal layer onto the dielectric layer;
depositing a photoresist over the at least 2000 angstrom thick TiW metal layer;
uniformly etching the at least 2000 angstrom thick TiW metal layer to form an etched TiW metal layer portion; and
selectively etching the etched TiW metal layer portion faster than the dielectric layer creating a uniformly patterned TiW metal layer.
2. The method of claim 1 with providing the substrate comprising providing the substrate in the form of a semiconductor substrate.
3. The method of claim 1 with uniformly etching comprising uniformly etching the at least 2000 angstrom thick TiW metal layer to form the etched TiW metal layer portion that is at least 200 angstroms thick.
4. The method of claim 3 with selectively etching comprising selectively etching the etched TiW metal layer portion at least 2.7 times faster than the dielectric layer.
5. The method of claim 3 with selectively etching comprising selectively etching the etched TiW metal layer portion to remove the etched TiW metal layer portion.
6. The method of claim 3 with selectively etching comprising selectively overetching the etched TiW metal layer portion to remove the etched TiW metal layer portion.
7. The method of claim 1 with uniformly etching comprising uniformly etching no more than 80% to 90% of the at least 2000 angstrom thick TiW metal layer to form the etched TiW metal layer portion.
8. The method of claim 7 with selectively etching comprising selectively etching the etched TiW metal layer portion at least 2.7 times faster than the dielectric layer.
9. The method of claim 7 with selectively etching comprising selectively etching the etched TiW metal layer portion to remove the etched TiW metal layer portion.
10. The method of claim 7 with selectively etching comprising selectively overetching the etched TiW metal layer portion to remove the etched TiW metal layer portion.
11. The method of claim 1 with uniformly etching comprising uniformly etching the at least 2000 angstrom thick TiW metal layer by processing in a Lam 9606 reactor with the following process settings:
Top Power = 350 Watts
Bottom Power = 93 Watts
Pressure = 7 mT
(milliTorricelli)
Ar = 32 sccm
(standard cubic centimeters/per minute)
BCl3 = 24 sccm
(standard cubic centimeters/per minute)
SF6 = 24 sccm
(standard cubic centimeters/per minute)
Total flow = 80 sccm
(standard cubic centimeters/per minute)
Gap = 3
(centimeter)
Clamp pressure = 5 T
(Torricelli)
Electrode temperature = 60° C.
12. The method of claim 1 with selectively etching comprising selectively etching the etched TiW metal layer portion at least 2.7 times faster than the dielectric layer.
13. The method of claim 1 with selectively etching comprising selectively etching the etched TiW metal layer portion to remove the etched TiW metal layer portion.
14. The method of claim 1 with selectively etching comprising selectively overetching the etched TiW metal layer portion to remove the etched TiW metal layer portion.
15. The method of claim 1 with selectively etching comprising selectively etching the etched TiW metal layer portion by processing in a Lam 9606 reactor with the following process settings:
Top Power = 600 Watts
Bottom Power = 70 Watts
Pressure = 10 mT
(milliTorricelli)
Ar = 0 sccm
(standard cubic centimeters per minute)
BCl3 = 80 sccm
(standard cubic centimeters per minute)
SF6 = 10 sccm
(standard cubic centimeters per minute)
Total flow = 90 sccm
(standard cubic centimeters per minute)
Gap = 3 cm
(centimeter)
Clamp pressure = 5 T
(Torricelli)
Electrode temperature = 60° C.
16. The method of claim 1 with depositing an at least 2000 angstrom thick TiW metal layer onto the dielectric layer comprising depositing an at least 2000 angstrom thick TiW metal film.
17. The method of claim 1 with depositing an at least 2000 angstrom thick TiW metal layer onto the dielectric layer comprising depositing an at least 3000 angstrom thick TiW metal film.
18. The method of claim 1 with depositing an at least 2000 angstrom thick TiW metal layer onto the dielectric layer comprising depositing an at least 3000 angstrom thick TiW metal film.
19. The method of claim 1 with depositing a dielectric layer comprising depositing a dielectric layer of silicon nitride on the substrate.
20. The method of claim 1 with depositing a dielectric layer comprising depositing a dielectric layer of silicon dioxide on the substrate.