Specific Process Knowledge/Etch/ICP Metal Etcher/Sinano1: Difference between revisions
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1) to reduce the coil power to 700W so that the dc bias of the etch increases & you sputter more of the polymer off. | 1) to reduce the coil power to 700W so that the dc bias of the etch increases & you sputter more of the polymer off. | ||
2) increase the platen temperature to 40 C so as to reduce polymer condensation on the wafer. | 2) increase the platen temperature to 40 C so as to reduce polymer condensation on the wafer. | ||
3) substitute Cl2 for some of the HBr - try a 50: 50 mix of Cl2 / HBr for the main etch with the same total gas flow. | 3) substitute Cl2 for some of the HBr - try a 50: 50 mix of Cl2 / HBr for the main etch with the same total gas flow. | ||
This will reduce the amount of polymerising species in the plasma & therefore help reduce the amount of sidewall deposition. | |||
I would try these separately. | |||
Just as a sanity check, have you got any pre-etch SEM images of the ZEP? There's a contradiction in the SEM images - in that you are seeing what looks to be undercut, whilst the trenches are also closing up. One effect is consistent with too little polymerisation whilst the other is caused by too much. The breakthrough step is actually quite a physical & directional etch, which usually doesn't cause an undercut. What exposed area do you have on the samples? | Just as a sanity check, have you got any pre-etch SEM images of the ZEP? There's a contradiction in the SEM images - in that you are seeing what looks to be undercut, whilst the trenches are also closing up. One effect is consistent with too little polymerisation whilst the other is caused by too much. The breakthrough step is actually quite a physical & directional etch, which usually doesn't cause an undercut. What exposed area do you have on the samples? | ||
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