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 can also be used for Cr evaporation for the same purpose, and for evaporation of Ag, Au, Cu, and Ge. We have also attempted to evaporate Zn, but this resulted in heavy contamination of the chamber that required a lot of effort to clean and the process was not stable. If you would like to deposit other metals you are welcome to ask.

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

Thermal Evaporator in LabManager

Process information

Materials evaporated in the Lesker Thermal Evaporator

Aluminium
Silver
Chromium
Germanium
Gold
Copper
(Zinc - we don't like to evaporate this material)

We can also evaporate gold in this evaporator and can develop processes for other materials if requested.

Equipment performance and process related parameters

Purpose	Deposition of metals	Thermal evaporation of metals
Performance	Film thickness	10Å - 1µm (Al and Ag) up to 80 nm (Cr)
	Deposition rate	0.5-2 Å/s (Al), 5 Å/s (Ag), 1 Å/s (Cr) In general, 0.5-10 Å/s is possible We need to develop a new process for each rate
	Thickness uniformity	approx. 13 % variation on a 4" wafer with 100 nm Al * approx. 23 % variation on a 4" wafer with 100 nm Ag * approx. 10 % variation on a 6" wafer with 100 nm Cr *
	Pumpdown time	about 15 min
Process parameter range	Process Temperature	Approximately room temperature
Process parameter range	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

* The variation is defined as (Max-Min)/Average for the various points measured on the wafer. The max. point was around the center and the min. somewhere along the edge. The exact location of the maximum thickness depends how the sample is placed relative to the point of maximum material flux. Measurement by Rebecca Ettlinger, Nov. 2018.