Specific Process Knowledge/Thin film deposition/thermalevaporator

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Thermal evaporator- A system for deposition of metals

Positioned in cleanroom A-1.

The main purpose of the thermal evaporator is to deposit Al for removing charging of the resist when doing EBL on isolating substrate.

It is not only usable for Al deposition. The thermal evaporator has room for two evaporation sources and thereby the possibility to make thin films of two different metals. At the moment not that many metals have been tested, so right now only Al and Ag can be evaporated. We have attempted to evaporate Au and Zn but these are not standard processes. If you would like to deposit these or other metals, please talk to the Thin Film group.

Compared to the Wordentec, the thermal evaporator is quicker to use if you only need to deposit on one wafer or on small samples, as it only takes about 15 minutes to pump down the chamber. You can also deposit thicker layers because the throw distance from source to sample is shorter, so the material use is more efficient: In the thermal evaporator, you get about 40-50 nm per metal pellet, whereas in the Wordentec you get about 15 nm per pellet.

The user manual, APV, technical information and contact information can be found in LabManager:

Thermal Evaporator in LabManager

Process information

Materials for thermal evaporation

• Aluminium
• Silver

Equipment performance and process related parameters

Purpose	Deposition of metals	Thermal evaporation of metals
Performance	Film thickness	10Å - 1µm
	Deposition rate	0.5-2 Å/s (Al), 5 Å/s (Ag) In general, 0.5-10 Å/s is possible We need to develop a new process for each rate
	Thickness uniformity	<5 % variation across a 4" wafer with 100 nm Al <10 % variation across a 4" wafer with 100 nm Ag
	Pumpdown time	about 15 min
Process parameter range	Process Temperature	Approximately room temperature
	Process pressure	Below 4*10-6 mbar
Substrates	Batch size	Up to 8" wafer Or several smaller pieces Deposition on one side of the substrate
	Substrate material allowed	Silicon wafers Quartz wafers Pyrex wafers
	Material allowed on the substrate	Silicon oxide Silicon (oxy)nitride Photoresist PMMA Mylar Metals