Simple Rate Characterization Process

A lithography-free method for determining deposition rates for non-standard processes via the use of a witness sample. Use cases include new materials, custom deposition parameters, deposition of material from a new cathode, co-sputtering deposition rates, and many more. The process is also useful for the measurement of deposition thickness when direct measurement is not possible on the working sample.

Method

Sample Prep

Prepare a small (~1cm square) piece of bare Si. Using a Sharpie, draw over a portion of the piece on the polished side. Place the drawn piece into the process chamber/sample holder using mounting methods as necessary, ensuring that the interface between the Si and marker regions is exposed. If you wish to average the deposition rate over a large area, repeat the prep for multiple samples and place them accordingly throughout the chamber/holder.

Deposition

Run the deposition process for which you wish to characterize and record all parameters. When developing a new sputtering recipe, remember to always stay below the maximum allowed power per target. If you are creating a process for a new material, consult with the tool owner or staff for suggestions on process parameters.

"Lift off"

When the deposition is complete, you may lift off the marker ink by rinsing it with acetone or agitating in a shallow acetone solution. Clean and dry pieces and dispose of any solutions as per standard solvent bench practices.

Measure Step Height

Using an appropriate metrology tool, determine the step height between the area of bare Si after lift-off and the area of deposited material. For transparent materials such as oxides, stylus profilometers such as the KLA Tencor P7 2D profilometer (MET-01) must be used. For opaque reflective materials such as metals and their alloys, tools such as the Filmetrics Profilm3D (MET-05) reflectometer can be used in addition to any stylus profilometer.