Specific Process Knowledge/Thin film deposition/Temescal

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E Beam Evaporator (Temescal)

The Temescal is a system for depositing metals by electron-beam evaporation. In e-beam evaporation, the deposition is line-of-sight directed from the source, which means it will coat only the surface of the sample facing directly towards the source. This makes it very useful for example for metals for lift-off. The system also has an ion source for in-situ Argon sputtering that can be used either for cleaning samples prior to deposition or to modify the film during deposition.

Wafers are loaded into the top of the chamber, which acts as a loadlock as it can be separated from the rest of the chamber by a large gate valve. Deposition will happen on all samples that are loaded together. You can load up to four 6" wafers or three 8" wafers for deposition on surfaces facing the evaporation source, or on up to one 6" wafer for tilted deposition (smaller samples may be tilted more). By using different sample holder inserts, you can deposit metals on samples of different sizes and shapes. Only one metal can be deposited at a time, but you can deposit many layers of different metals one after the other. The system contains 6 metals at a time and the metals are exchanged based on user requests, so please request the metals you wish well in advance.

The Temescal E-beam evaporator in cleanroom A-5

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

E Beam Evaporator (Temescal) in LabManager

Process information

• Acceptance Test

Materials for e-beam evaporation

• Aluminium (Al)
• Chromium (Cr)
• Copper (Cu)
• Gold (Au)
• Molybdenum (Mo)
• Nickel (Ni)
• Palladium (Pd)
• Platinum (Pt)
• Silver (Ag)
• Tantalum (Ta)
• Tin (Sn)
• Titanium (Ti)
• Tungsten (W) - thinner layers

Note that to date (July 2018) we have processes available for deposition of Al, Cr, Au, Ni, Pd, Ag, Ti, and W as well as Ru. More will be available as they are requested, e.g., Nb is expected in the early fall of 2018.

Equipment performance and process related parameters for the Temescal E-beam evaporator

Purpose	Deposition of metals	E-beam evaporation of metals Line-of-sight deposition Possible to tilt sample Possible to ion clean samples Possible to modify deposition by Ar ion bombardment
Performance	Film thickness	10Å - 1µm* (for some materials)
	Deposition rate	0.5Å/s - 10Å/s
	Thickness uniformity	up to 3 % Wafer-in-Wafer variation ** up to 2 % Wafer-to-Wafer and Batch-to-Batch variation **
	Thickness accuracy	May vary by up to about +/- 10 % Less accurate for films below 20 nm
Process parameter range	Process Temperature	Approximately room temperature
	Process pressure	Below 1*10-6 mbar before deposition starts Below 5*10-6 mbar during deposition
	Source-substrate distance	69.85 cm
Substrates	Batch size	Up to four 6" wafers per standard run Or up to three 8" wafers Up to one 6" wafer with tilt Deposition on one side of the substrate
	Substrate material allowed	Silicon wafers Quartz wafers Pyrex wafers See also the cross-contamination sheet
	Material allowed on the substrate	Silicon oxide Silicon (oxy)nitride Photoresist PMMA Mylar Metals See also the cross-contamination sheet

* For thicknesses above 600 nm please request permission so we can ensure that enough material will be present.

** Defined as the ratio of the standard deviation to the average of the measurement made using the DektakXT

Quality control (QC) for the Temescal

We are still developing the QC procedure for the Temescal (July 2018).

Other stuff to add

• How e-beam evaporation works (is it elsewhere?) and why you need to be aware that the e-beam hits the metal and not the crucible
• How the machine measures the thickness (QCM, why tooling factor may depend on deposition rate, why is stress and delamination an issue)
• Line-of-sight deposition
• Results from Acceptance test including SEM images and stuff about ion etch rate
• Stuff that we say in the manual that you can see on Labadvisor
• Stuff about the Hula
• Stuff about heating during deposition and water cooling and cooling times