Nitrogen-free dielectric anti-reflective coating and hardmask
Methods are provided for depositing a dielectric material. The dielectric material may be used for an anti-reflective coating or as a hardmask. In one aspect, a method is provided for processing a substrate including introducing a processing gas comprising a silane-based compound and an oxygen and carbon containing compound to the processing chamber and reacting the processing gas to deposit a nitrogen-free dielectric material on the substrate. The dielectric material comprises silicon and oxygen. In another aspect, the dielectric material forms one or both layers in a dual layer anti-reflective coating.
1. A method for processing a substrate, comprising:
depositing a first anti-reflective layer; and
depositing a second anti-reflective layer on the first anti-reflective layer by a process comprising:
introducing a processing gas comprising a compound comprising an oxygen-free silane-based compound and an oxygen and carbon containing compound to the processing chamber; and
reacting the processing gas to deposit a nitrogen-free dielectric material on the substrate, wherein the nitrogen-free dielectric material comprises at least silicon and oxygen.
2. The method of claim 1 , wherein the oxygen-free silane-based compound comprises one or more compounds having the formula Si X H 2X+2 , Si X H Y Cl Z , (R) Z Si X H Y , or combinations thereof, wherein X is 1 to 4, Y is 0 to 2X+1, Z is 2X+2, and R is an organic group.
3. The method of claim 1 , wherein the oxygen and carbon containing compound is an organosilicon selected from the group of tetraethoxysilane (TEOS), triethoxyfluorosilane (TEFS), 1,3,5,7-tetramethylcyclotetrasiloxane (TMCTS), dimethyldiethoxysilane, and combinations thereof.
4. The method of claim 3 , wherein the ratio of the oxygen-free silane-based compound to the oxygen-containing organosilicon compound is between about 1 sccm:20 mgm and about 6 sccm:5 mgm.
5. The method of claim 1 , wherein the second anti-reflective layer comprises silicon, oxygen, and carbon, and has an oxygen content between about 15 atomic percentage and about 50 atomic percentage of oxygen.
6. The method of claim 1 , wherein the processing gas further comprises an inert gas selected from the group of argon, helium, neon, xenon, or krypton, and combinations thereof.
7. The method of claim 1 , wherein the reacting the processing gas comprises generating a plasma at a RF power level between about 50 watts and about 10,000 watts at a pressure between about 1 Torr and about 50 Torr and a substrate temperature between about 100° C. and about 1000° C.
8. The method of claim 1 , wherein the first anti-reflective layer is depositing by introducing a second processing gas comprising a compound comprising an oxygen-free silane-based compound and an oxygen and carbon containing compound to the processing chamber and reacting the second processing gas to deposit a nitrogen-free dielectric material on the substrate comprising at least silicon and oxygen.
9. The method of claim 1 , further comprising an oxide capping layer disposed on the second anti-reflective coating.
10. The method of claim 1 , further comprising exposing the second anti-reflective coating to a nitrogen-free oxidizing plasma.
11. The method of claim 1 , wherein the first anti-reflective coating and the second anti-reflective coating have a combined reflectivity below 1 percentage.
12. The method of claim 1 , further comprising:
depositing a photoresist material on the anti-reflective coating; and
patterning the photoresist layer.
13. The method of claim 12 , further comprising:
etching the second anti-reflective coating and any underlying dielectric material to define an interconnect opening therethrough; and
depositing one or more conductive materials to fill the interconnect opening.
14. The method of claim 1 , wherein the oxygen and carbon containing compound is carbon dioxide.
15. The method of claim 1 , wherein the first antireflective coating has an extinction coefficient that is higher than the extinction coefficient for the second antireflective coating.
16. The method of claim 1 , wherein the processing gas further comprises an inert gas selected from the group of argon, helium, neon, xenon, or krypton, and combinations thereof.
17. The method of claim 1 , wherein the deposited nitrogen-free dielectric material has an index of refraction between about 1.5 and about 2.2.
18. The method of claim 1 , wherein the deposited nitrogen-free dielectric material has an extinction coefficient of between about 0 and about 2.
19. The method of claim 7 , wherein the reacting the processing gas comprises generating a plasma at a RF power level between about 50 watts and about 10,000 watts at a pressure between about 1 Torr and about 50 Torr and a substrate temperature between about 100° C. and about 1000° C.
20. The method of claim 1 , wherein the first anti-reflective coating and the second anti-reflective coating have an etch selectivity of oxide to anti-reflective coating of about 4:1 or greater.