Oxygen-containing ceramic hard masks and associated wet-cleans

1. A method of forming a hard mask film on a semiconductor substrate, the method comprising:

receiving a semiconductor substrate in a plasma-enhanced chemical vapor deposition (PECVD) process chamber; and

forming by PEVCD on the substrate an oxygen-containing ceramic hard mask film, the film being etch selective to copper, resistant to plasma dry-etch and removable by wet-etch;

wherein the film formation comprises,

flowing a process gas consisting essentially of He, C 2 H 2 , CO 2 and B 2 H 6 , and a carrier gas into the process chamber; and

forming plasma to deposit the oxygen-containing ceramic hard mask film consisting essentially of the elements C, H, B and at least 5% O on the substrate.

2. The method of claim 1 , wherein the percentage of precursors relative to total process gas flow is about He 80-83%/C 2 H 2 10-11%/CO 2 5-8%/B 2 H 6 2-3%.

3. The method of claim 2 , wherein the percentage of precursors relative to total process gas flow is about He 82%/C 2 H 2 10.5%/CO 2 5%/B 2 H 6 2.5%.

4. The method of claim 2 , wherein the percentage of precursors relative to total process gas flow is about He 80%/C 2 H 2 10%/CO 2 7.5%/B 2 H 6 2.5%.

5. The method of claim 1 , wherein the total flow of precursor process gas is about 10000 sccm.

6. The method of claim 1 , further comprising removing the oxygen-containing ceramic hard mask film from the substrate with a wet etch.

7. The method of claim 6 , where in the wet etch chemistry comprises an oxidant and a strong acid or base compound.

8. The method of claim 7 , wherein the wet etch chemistry further comprises a metal corrosion inhibitor.

9. The method of claim 6 , where in the wet etch chemistry comprises water.

10. The method of claim 9 , wherein the wet etch chemistry further comprises a metal corrosion inhibitor.

11. The method of claim 1 , wherein the formed hard mask layer is deposited over a layer of dielectric having a dielectric constant of less than about 2.8, and wherein the formed hard mask film has an etch selectivity of at least about 8:1 versus the dielectric in a dry plasma etch.

12. The method of claim 1 , wherein the formed hard mask layer is deposited over a layer of polysilicon.

13. The method of claim 1 , wherein the wet etch chemistry comprises 1:1 96% H 2 SO 4 :30% H 2 O 2 .

14. An apparatus for processing a hard mask film on a semiconductor substrate, the apparatus comprising:

a plasma-enhanced chemical vapor deposition (PECVD) process chamber;

a support in the process chamber for a semiconductor wafer substrate for holding the wafer substrate in position during hard mask deposition; and

a controller comprising program instructions for a process of:

receiving a semiconductor wafer substrate in a plasma-enhanced chemical vapor deposition (PECVD) process chamber; and

forming by PEVCD on the substrate an oxygen-containing ceramic hard mask film, the film being etch selective to copper, resistant to plasma dry-etch and removable by wet-etch, and wherein the film formation comprises,

flowing a process gas consisting essentially of He, C 2 H 2 , CO 2 and B 2 H 6 , and a carrier gas into the process chamber; and

forming plasma to deposit the oxygen-containing ceramic hard mask film consisting essentially of the elements C, H, B and at least 5% O on the substrate.

15. The apparatus of claim 14 , further comprising:

a wet etch process chamber; and

a controller comprising program instructions for a process of:

receiving the semiconductor wafer substrate with the oxygen-containing ceramic hard mask film formed thereon; and

removing the oxygen-containing ceramic hard mask film from the substrate with a wet etch.

16. The apparatus of claim 14 , wherein the wet etch chemistry comprises 1:1 96% H 2 SO 4 : 30% H 2 O 2 .