Method and system for forming patterned structures including silicon nitride

1. A method of forming patterned structures on a surface of a substrate, the method comprising the steps of:

providing a substrate comprising sacrificial features formed thereon within a reaction chamber; and

using a cyclical plasma process, depositing a layer comprising silicon nitride overlying the sacrificial features, the step of depositing the layer comprising silicon nitride comprising:

providing a silicon precursor to the reaction chamber for a silicon precursor pulse period;

providing a nitrogen reactant to the reaction chamber;

providing a hydrogen reactant to the reaction; and

providing a plasma power to form a plasma within the reaction chamber for a plasma pulse period,

wherein, during the step of depositing, a portion of the sacrificial features is isotropically removed.

2. The method of claim 1 , wherein the nitrogen reactant is selected from the group consisting of N 2 O and NO.

3. The method of claim 1 , wherein the hydrogen reactant comprises NH 3 or N 2 H 2 .

4. The method of claim 1 , wherein a volumetric percent of hydrogen reactant in gas provided to the reaction chamber during the step of providing a plasma power is between about 0.02% and about 0.07%.

5. The method of claim 1 , wherein the cyclical plasma process comprises a plasma-enhanced atomic layer deposition process.

6. The method of claim 1 , wherein a frequency of power used during the cyclical plasma process is between about 26 MHz and about 28 MHz.

7. The method of claim 1 , wherein a plasma power during the plasma pulse period is greater than zero and less than 1500 W.

8. The method of claim 1 , wherein the silicon precursor pulse period, providing the nitrogen reactant, and providing the hydrogen reactant overlap.

9. The method of claim 1 , wherein the plasma pulse period, providing the nitrogen reactant, and providing the hydrogen reactant overlap.

10. The method of claim 1 , wherein the nitrogen reactant is continuously supplied to the reaction chamber during the cyclical plasma process.

11. The method of claim 1 , wherein the hydrogen reactant is continuously supplied to the reaction chamber during the cyclical plasma process.

12. The method of claim 1 , further comprising a step of using reactive ion etching to remove a portion of the layer comprising silicon nitride.

13. The method of claim 1 , further comprising a step of controlling an etch profile of the sacrificial features during the cyclical plasma process by manipulating one or more of a flowrate of the hydrogen reactant, a pressure within the reaction chamber, a plasma power, a substrate temperature, and a plasma power pulse time.

14. The method of claim 1 , further comprising a step of controlling an etch profile of the sacrificial features during the cyclical plasma process by manipulating one or more of a flow ratio of the hydrogen reactant, a pressure within the reaction chamber, a plasma power, a substrate temperature, and a plasma power pulse time.

15. The method of claim 1 , wherein the sacrificial features comprise one or more of photoresist, spin on carbon, carbon hard mask, and spin on hard mask.

16. The method of claim 1 , wherein a substrate temperature during the step of depositing the layer comprising silicon nitride is between about 250° C. and about 300° C. or about 75° C. and about 350° C.

17. The method of claim 1 , wherein a pressure within the reaction chamber during the step of depositing the layer comprising silicon nitride is between about 1600 Pa and about 2400 Pa.

18. The method of claim 1 , further comprising a step of removing remaining portions of the sacrificial features to thereby form the patterned structures.

19. The method of claim 18 , further comprising a step of etching a portion of the substrate using the patterned structures.