Specific Process Knowledge/Thin film deposition/Deposition of Silver/Deposition of Silver

Feedback to this page: click here

All contents by Nanolab staff.

Thermal deposition of Silver

Silver can be thermally evaporated in the Wordentec and the Thermal Evaporator. The process in the Thermal Evaporator (Lesker) is described here.

Using the Wordentec

The Wordentec is useful if you need to deposit a thin layer on more than three wafers: You can load up to six 6" wafers at a time, but you can only add 8 pellets at a time, which in the Wordentec gives a total of approx. 160 nm (or 20 nm per wafer on six wafers). The uniformity for a 6" wafer will also be better in the Wordentec, while in the Thermal Evaporator it is easier to deposit thicker layers. Note that the pumping time for the Wordentec is at least 1 hour, which means that this is much slower than the Thermal Evaporator unless you are depositing thin layers on many wafers.

Use process number 22 in the process list.

Only the thickness needs to be changed. The deposition rate is set to 2.5 Å/s (contact responsible Nanolab personnel if you like to run with a different rate).

Additional information - process parameters that do NOT need to be changed

Here below are the process parameters of the Ag program in Wordentec. These are already in the program and do not need to be changed- this is written as a back-up to have a list with all process parameters.

(These parameters are listed in material 13 Ag the material section: - please contact the process specialist if you are not familiar with this.) For thermal Ag deposition use:

Max power: 6.7 % (With a higher max power, the deposition rate will have large fluctuations).

Soak power 1: 4 %

Soak power 2: 6.6 %

Soak time 2: 1 min

This gives a depositon rate of about 2.5 Å/s (to be set in the process parameters).

To get the right thickness measurement of the quartz crystals, use the prameters

Density: 10.5 (thermal evap. of Al 2.7)

Z-ratio: 0.529 (thermal evap. of Al 1.08)

Master Tooling should be set to: 120% (to get the requested layer thickness on the wafer). (Master tooling for Al = 167%).