Specific Process Knowledge/Etch/DRIE-Pegasus/Pegasus-3/SiO2 etch: Difference between revisions
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! Wafer number !! C4F8 !! SF6 flow !! Ar !! Platen power !! Pressure || Uniformity results || Center Etch rate | ! Wafer number !! C4F8 !! SF6 flow !! Ar !! Platen power !! Pressure || Uniformity results || Center Etch rate | ||
|- | |- | ||
| Y34 || 50 sccm|| 50 sccm|| 0 sccm|| 100 W || 80 mTorr || ±23.3% || 36.0 nm/min | | Y34 || 50 sccm|| 50 sccm|| 0 sccm|| 100 W || 80 mTorr || ±23.3% || 36.0 nm/min (highest) | ||
|- | |- | ||
| Y35 || 25 sccm|| 75 sccm|| 0 sccm|| 100 W || 80 mTorr || ±20.8% || 41.3 nm/min | | Y35 || 25 sccm|| 75 sccm|| 0 sccm|| 100 W || 80 mTorr || ±20.8% || 41.3 nm/min (highest) | ||
|- | |- | ||
| Y36 || 25 sccm|| 75 sccm|| 0 sccm|| 100 W || 10 mTorr || ±22.1% || 36.2 nm/min | | Y36 || 25 sccm|| 75 sccm|| 0 sccm|| 100 W || 10 mTorr || ±22.1% || 36.2 nm/min (lowest) | ||
|- | |- | ||
| Y37 ||25 sccm|| 75 sccm|| 0 sccm|| 100 W || 40 mTorr || ±24.6% || 24.4 nm/min | | Y37 ||25 sccm|| 75 sccm|| 0 sccm|| 100 W || 40 mTorr || ±24.6% || 24.4 nm/min (lowest) | ||
|- | |- | ||
| Y38 || 25 sccm|| 75 sccm|| 0 sccm|| 100 W || 60 mTorr || ± 8.1% || 34.0 nm/min | | Y38 || 25 sccm|| 75 sccm|| 0 sccm|| 100 W || 60 mTorr || ± 8.1% || 34.0 nm/min (highest in center and at edge) | ||
|- | |- | ||
| Y39 || 50 sccm|| 150 sccm|| 0 sccm|| 100 W || 10 mTorr || ±25.0% || 34.8 nm/min | | Y39 || 50 sccm|| 150 sccm|| 0 sccm|| 100 W || 10 mTorr || ±25.0% || 34.8 nm/min (lowest) | ||
|- | |- | ||
| Y40 || 8.33 sccm|| 50 sccm|| 100 sccm|| 100 W || 10 mTorr || ±15.1% || 35.8 n/min | | Y40 || 8.33 sccm|| 50 sccm|| 100 sccm|| 100 W || 10 mTorr || ±15.1% || 35.8 n/min (lowest) | ||
|} | |} | ||
[[File:Peg3 SiO2 uniformity Y34 to Y40.jpg|400px]] | [[File:Peg3 SiO2 uniformity Y34 to Y40.jpg|400px]] | ||
[[File:Peg3 SiO2 uniformity normalized Y34 to Y40.jpg|400px]] | [[File:Peg3 SiO2 uniformity normalized Y34 to Y40.jpg|400px]] | ||
Revision as of 14:16, 25 January 2024
Etching of very thin layer of SiO2
Pegasus 3 is not meant to be used as an SiO2 etcher. Please do not develop SiO2 recipes on this machine. Often SiO2 etch recipes are very polymerizing and that can disturb the chamber conditions for the silicon etching recipes.
The recipe developed here is only for etching through a very thin SiO2 layer and does not have a high selectivity to silicon to avoid the recipe to become too polymerizing. It is also not very uniform over the wafer, so when it is used for etching down to silicon it will also etch a lot in the silicon and in areas more than other.
Test work done
Unless otherwise stated, all content in this section was done by Berit Herstrøm, DTU Nanolab
The tests were done on 6" wafers. Silicon wafers with 1µm thermal SiO2 and mask less. Measurements were done on the ellipsometer before at after the etch to map the etch rate.
| Wafer number | C4F8 | SF6 flow | Ar | Platen power | Pressure | Uniformity results | Center Etch rate |
|---|---|---|---|---|---|---|---|
| Y34 | 50 sccm | 50 sccm | 0 sccm | 100 W | 80 mTorr | ±23.3% | 36.0 nm/min (highest) |
| Y35 | 25 sccm | 75 sccm | 0 sccm | 100 W | 80 mTorr | ±20.8% | 41.3 nm/min (highest) |
| Y36 | 25 sccm | 75 sccm | 0 sccm | 100 W | 10 mTorr | ±22.1% | 36.2 nm/min (lowest) |
| Y37 | 25 sccm | 75 sccm | 0 sccm | 100 W | 40 mTorr | ±24.6% | 24.4 nm/min (lowest) |
| Y38 | 25 sccm | 75 sccm | 0 sccm | 100 W | 60 mTorr | ± 8.1% | 34.0 nm/min (highest in center and at edge) |
| Y39 | 50 sccm | 150 sccm | 0 sccm | 100 W | 10 mTorr | ±25.0% | 34.8 nm/min (lowest) |
| Y40 | 8.33 sccm | 50 sccm | 100 sccm | 100 W | 10 mTorr | ±15.1% | 35.8 n/min (lowest) |
