Simplified pitch doubling process flow
A method for fabricating a semiconductor device comprises patterning a layer of photoresist material to form a plurality of mandrels in a device array region. The method further comprises depositing an oxide material over the plurality of mandrels and over a device peripheral region. The method further comprises forming a pattern of photoresist material over the oxide material in the device peripheral region. The method further comprises anisotropically etching the oxide material from exposed horizontal surfaces in the device array region. The method further comprises selectively etching photoresist material from the device array region and from the device peripheral region.
1. A method for fabricating a semiconductor device, the method comprising:
patterning a layer of photoresist material to form a plurality of mandrels formed of photoresist in a device array region;
depositing an oxide material on the plurality of mandrels and over a device peripheral region at a deposition temperature of about 200° C. or less;
forming a pattern of photoresist material over the oxide material in the device peripheral region;
anisotropically etching the oxide material from exposed horizontal surfaces in the device array region, thereby forming spacers from the oxide material, wherein the pattern of the photoresist material extends over the ends of the spacers;
transferring a pattern defined by the spacers to an underlying material, wherein the pattern of the photoresist material blocks transfer of the ends of the spacers to the underlying material; and
selectively etching photoresist material from the device array region and from the device peripheral region.
2. The method of claim 1 , further comprising isotropically etching the plurality of mandrels to form a plurality of modified mandrels before depositing the oxide material.
3. The method of claim 2 , wherein isotropically etching the plurality of mandrels comprises using an oxygen-containing plasma selected from the group consisting of a SO 2 /O 2 /N 2 /Ar plasma, a Cl 2 /O 2 /He plasma, and a HBr/O 2 /N 2 plasma.
4. The method of claim 1 , further comprising anisotropically etching the oxide material from exposed horizontal surfaces in the device peripheral region.
5. The method of claim 1 , wherein patterning the layer of photoresist comprises using light having a wavelength selected from the group consisting of 157 nm, 193 nm, 248 nm, and 365 nm.
6. The method of claim 1 , wherein patterning the layer of photoresist comprises using nano-imprint lithography.
7. The method of claim 1 , wherein the layer of photoresist material patterned in the device array region and the pattern of photoresist material formed in the device peripheral region comprise the same material.
8. The method of claim 1 , wherein anisotropically etching the oxide material comprises using a HBr/Cl 2 -containing plasma.
9. The method of claim 1 , wherein the modified mandrels have a width between about 35 nm and about 70 nm.
10. The method of claim 1 , wherein the modified mandrels have a width between about 40 nm and about 50 nm.
11. The method of claim 1 , wherein the oxide material is deposited using an atomic layer deposition technique.
12. The method of claim 1 , wherein the oxide material is deposited at a temperature less than about 150° C.
13. The method of claim 1 , wherein the oxide material is deposited at a temperature less than about 125° C.
14. The method of claim 1 , wherein the pattern of photoresist material in the device peripheral region forms a feature selected from the group consisting of a landing pad, a transistor, and an interconnect.
15. The method of claim 1 , wherein the layer of photoresist material is patterned over a hard mask layer.
16. The method of claim 1 , wherein the layer of photoresist material is patterned over a silicon oxynitride layer that is positioned over a carbon layer.
17. The method of claim 1 , wherein the plurality of mandrels have a height between about 50 nm and about 300 nm.
18. The method of claim 1 , wherein the mandrels have a width between about 80 nm and about 120 nm.
19. The method of claim 1 , wherein the layer of photoresist material comprises a material selected from the group consisting of amorphous carbon, argon fluoride photoresist, and krypton fluoride photoresist.