Specific Process Knowledge/Thin film deposition/Wordentec

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Wordentec QCL 800

Wordentec: positioned in cleanroom D-2 in the Wordentec room

The Wordentec is a machine for:

• Deposition of metal through E-beam deposition
• Deposition of metal through thermal evaporation
• Deposition of materials through DC sputtering
• Cleaning of samples before deposition through Argon RF sputter clean

The Wordentec is designed to deposit on 1-6 samples in sequence, samples of a size up to 6" in diameter. Adaptors exist for deposition on 2", 4" and 6" wafers, but deposition is possible on samples of almost any size and shape, as long as they do not exceed the size of a 6" substrate. The Wordentec supports either single sample deposition on each sample or batch deposition on six wafers in sequence. It is possible to freely combine processes from the machines different sources.

The user manual, quality control procedure and results, user APV, technical information and contact information can be found in LabManager:

Wordentec in LabManager

Process information

The metals available for E-beam evaporation and their standard deposition rates are:

Metal	Deposition rate [Å/s]
Titanium (Ti)	10
Chromium (Cr)	10
Aluminium (Al)	10
Nickel (Ni)	10
Platinum (Pt)	10
Gold (Au)	10

Temperature and roughness studies of Au deposition processes in the Wordentec

E-beam evaporation of some materials like Au and Al can affect the underlying layers and thin resists such as E-beam sensitive resists can get exposed or their topography may change. Cases of releasing bubbles of the solvent will create a crater-like surface on some materials. In most cases this only affects the areas containing resist, hence liftoff is often easier and the areas without resist will have good adhesion.

Delaminating Au film on thin E-beam resist

Thermal evaporation materials

We currently have Aluminium, Silver and Germanium available to deposit through thermal evaporation.

Sputter materials

It is possible to sputter deposit almost any material, provided that it is possible to deposit with DC sputtering. The materials available currently are:

• TiW alloy (10%/90% by weight)
• Aluminium (Al)
• Chromium (Cr)
• Silver (Ag)
• Titanium (Ti)
• Silicon (Si)
• NiV alloy

More information about deposition rates and surface roughness can be found by clicking on the different elements.

Equipment performance and process related parameters Wordentec

Purpose	Deposition of metals	E-beam evaporation Sputtering Thermal evaporation
Performance	Film thickness	~10Å - 1µm*
	Deposition rate	~2.5Å/s - 15Å/s
	Thickness uniformity	~6 % variation across a 4" wafer for thermal evaporation of 100 nm Al ** ~9 % variation across a 4" wafer for e-beam evaporation of 100 nm Ni ** ~6 % variation across a 4" wafer for e-beam evaporation of 10 nm Ti + 90 nm Au **
Process parameter range	Process Temperature	Less than 80 oC
	Process pressure	~3x10-7 - 4x10-6 mbar
Substrates	Batch size	24x2" wafers or 6x4" wafers or 6x6" wafers 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 SU-8 Metals

* For e-beam evaporation and sputtering, permission is required for thicknesses above 600 nm. For thermal evaporation, permission is required for thicknesses above 120 nm. This is to ensure that there will be enough material present. Contact metal@danchip.dtu.dk or thinfilm@danchip.dtu.dk

** % variation calculated as (Max-Min)/Average. Note that for thermally evaporated Al, the max was on one side of the wafer and the minimum directly opposite.

Quality control (QC) for Wordentec

Quality control (QC) for Wordentec

QC procedure for Wordentec The newest QC data for Wordentec QC Recipe: Au Ni Deposition rate 10 Å/s 10 Å/s Thickness 1000 Å 1000 Å Pressure Below 2*10-6 mbar Below 2*10-6 mbar QC limits Wordentec Measured average thickness (Å) 900-1100 Å Lowest accepted deposition rate (Å/s) 6 Å/s Thicknesses are measured in 5 points with one of the Dektak instruments.