Specific Process Knowledge/Thin film deposition/Deposition of Aluminium
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Deposition of Aluminium
Aluminium can be deposited by e-beam evaporation, by sputtering and by thermal evaporation. In the chart below you can compare the different methods on the different deposition equipment.
Sputtering of Aluminium
Aluminium may be sputter deposited in either Wordentec or the Lesker sputter system.
E-beam evaporation of Aluminium
Aluminium can be deposited be e-beam assisted evaporation in wordentec, Physimeca and Temescal
Thermal deposition of Aluminium
In the Wordentec and the Thermal evaporator aluminium can be deposited by Thermal deposition
| E-beam evaporation (Temescal) | E-beam evaporation (Physimeca) | E-beam evaporation (Wordentec) | Sputter deposition (Wordentec) | Thermal evaporation (Wordentec) | Thermal evaporation (Thermal Evaporator) | |
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| General description |
E-beam deposition of Aluminium |
E-beam deposition of Aluminium |
E-beam deposition of Aluminium |
Sputter deposition of Aluminium |
Aluminum deposition onto unexposed e-beam resist |
Aluminum deposition onto unexposed e-beam resist |
| Pre-clean | Ar ion etch | None | RF Ar clean | RF Ar clean | RF Ar clean | None |
| Layer thickness | 10Å to 1 µm* | 10Å to 0.5 µm ** | 10Å to 1 µm* | 10Å to ~0.5µm (very time consuming ) | 10Å to 0.2 µm*** (this uses all Al in the boat) | 10Å to 1 µm** |
| Deposition rate | 0.5Å/s to 15Å/s | 0.5Å/s to 15Å/s | 10Å/s to 15Å/s | Depending on process parameters, up to ~2.5 Å/s | ~1.5Å/s to 2Å/s | 1 Å/s |
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| Pumping time from wafer load |
Approx. 20 min |
Approx. 10 min |
Approx. 1 hour |
Approx. 1 hour |
Approx. 1 hour |
Approx. 15 min |
| Allowed substrates |
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| Allowed materials |
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| Comment | * Thickness above 600 nm: ask for permission
It is possible to tilt the substrate. Pumpdown approx. 20 min. |
** Thickness above 200 nm: ask for permission. | * Thickness above 600 nm: ask for permission.
Pumpdown approx. 1 hour. |
Pumpdown approx. 1 hour. | ***Thickness above 120 nm: ask for permission
Pumpdown approx. 1 hour. |
**Thickness above 200 nm: ask for permission.
Pumpdown approx. 10 min. |
* For thicknesses above 600 nm please get permission from ThinFilm group by writing to metal@danchip.dtu.dk
** For thicknesses above 200 nm please get permission from ThinFilm group by writing to metal@danchip.dtu.dk
*** For thicknesses above 120 nm please get permission from ThinFilm group by writing to thinfilm@danchip.dtu.dk
Aluminium deposition on ZEP520A for lift-off - comparison of thermal and e-beam evaporation
This is a small study of which aluminium deposition that is best for aluminium lift-off on ZEP520A resist and a very thin layer of aluminium (~20nm). The grain size is compared for the different methods.
The conclusion was that e-beam evaporation of aluminium in the Alcatel at 15Å/s gave the best result.
See details of the study here.
Aluminium deposition on AZ5214 for lift-off
Negative photolithographi process is recomended.
Positive photolithographi process from 1,5µ is possible especially for thin layers of metal.
The more pattern the easyer lift.
It was tried(jan09) to lift 2,5µ Al on 4,2µ negative resist on top of 11µ Apox SiO2 in acetone sonic-bath.
This process was done in steps evaporating 5000Å a time with 5min pause and pressure down to at least 2E-6.
Roughness of thermally evaporated aluminium
A study by AFM was performed to examine Al films deposited with thermal evaporation in the Wordentec. See details here. here.