Specific Process Knowledge/Etch/ICP Metal Etcher
The ICP Metal Etcher in short
Despite its name the metal etcher doesn't etch metals in general. Currently, the list of metals that you can etch is quite short:
- aluminium
- titanium
- chromium
Over time it is our intention to add other materials to the list such as molybdenum, tungsten, titaniumtungsten, titaniumoxides or piezo-materials such as ZnO. However, currently you are not even allowed to expose other metals to the plasma.
Aluminium etch
The aluminium etch has two steps:
- Breakthrough
- The breakthrough step is designed to break through the native aluminium oxide layer that is present on all aluminium surfaces. The duration of this step should remain fixed.
- Main
- The main step etches bulk aluminium.
| Parameter | Process step | |
|---|---|---|
| width="225" Breakthrough | width="225" Main | |
| Time (secs) | 20 | 40 (variable) |
| HBr (sccm) | - | 15 |
| Cl2 (sccm) | 20 | 25 |
| Pressure (mTorr) | 4, Strike 3 secs @ 15 mTorr??? | 1 |
| Coil power (W) | 600 | 500 |
| Platen power (W) | 125 | 100 |
| Temperature (oC) | 20 | 20 |
| Spacers (mm) | 30 | 30 |
Etching of nanostructures in silicon using the ICP Metal Etcher or DRIE Pegasus
- The 180 nm zep resist profiles (Wafer WF_2B1_feb06_2011)
- The 340 nm zep resist profiles (Wafer WF_2C1_feb2011)
- The 211 nm zep resist profiles (Wafer WF_2E02_mar23_2011)
| Recipe Sinano | 3.0 | 3.1 | 3.2 | 3.3 | 3.4 | 4.0 | 3.5 | 3.6 | 3.3 | 3.7 | 3.31 | 3.31 | 3.32 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Cl2 (sccm) | 0 | 0 | 0 | 0 | 0 | 20 | 15 | 15 | 0 | 0 | 0 | 0 | 0 |
| BCl3 (sccm) | 5 | 3 | 5 | 5 | 5 | 0 | 5 | 5 | 5 | 5 | 5 | 5 | 5 |
| HBr (sccm) | 15 | 17 | 15 | 15 | 15 | 0 | 0 | 0 | 15 | 15 | 15 | 15 | 15 |
| Coil power (W) | 900 L | 900 F | 900 F | 900 F | 900 F | 900 L | 900 L | 900 F | 900 F | 900 L | 900 F | 900 F | 900 F |
| Platen power (W) | 50 | 50 | 60 | 75 | 90 | 60 | 60 | 60 | 75 | 60 | 75 | 75 | 30 |
| Pressure (mtorr) | 2 | 2 | 2 | 2 | 2 | 2 | 5 | 10 | 2 | 10 | 2 | 2 | 2 |
| Temperature (oC) | 20 | 20 | 20 | 20 | 20 | 20 | 20 | 20 | 20 | 50 | 50 | 50 | 50 |
| Spacers (mm) | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 30 | 100 |
| Process time (s) | 150 | 180 | 120 | 180 | 120 | 90 | 120 | 180 | 300 | 180 | 180 | 180 | 180 |
| Etch rates (nm/min) | |||||||||||||
| Averages | 311 | 104 | 92 | 105 | 116 | 169 | 108 | 79 | 101 | 66 | 91 | 98 | 59 |
| Std. Dev | 44 | 15 | 15 | 21 | 22 | 9 | 11 | 31 | 29 | 4 | 28 | 18 | 12 |
| Zep etch rate (nm/min) | |||||||||||||
| 30 | 40 | 51 | 67 | 45 | 59 | 53 | 36 | 19 | |||||
| Sidewall angle (degrees) | |||||||||||||
| Averages | 82 | 82 | 82 | 82 | 82 | 84 | 81 | 83 | 83 | 85 | 80 | 83 | 79 |
| Std. Dev | 2 | 2 | 1 | 1 | 1 | 1 | 1 | 2 | 2 | 1 | 3 | 2 | 2 |
| CD loss (nm pr edge) | |||||||||||||
| Averages | 65 | -11 | -15 | -2 | -11 | 67 | 63 | -29 | -5 | -29 | 10 | -14 | -17 |
| Std. Dev | 30 | 5 | 2 | 4 | 3 | 29 | 27 | 6 | 5 | 8 | 7 | 8 | 10 |
| Bowing (nm) | |||||||||||||
| Averages | 31 | 31 | 15 | 6 | 5 | 22 | 12 | 15 | 28 | 13 | 25 | 1 | -2 |
| Std. Dev | 6 | 7 | 3 | 6 | 4 | 5 | 2 | 6 | 9 | 7 | 5 | 2 | 2 |
| Botton curvature | |||||||||||||
| Averages | -9 | -6 | -9 | -11 | -9 | 9 | -4 | -8 | -24 | -2 | -9 | -13 | -10 |
| Std. Dev | 22 | 19 | 19 | 11 | 7 | 17 | 15 | 15 | 12 | 15 | 13 | 17 | 18 |