Hello,

I am planning to work with acidic piranha solution made from sulphuric acid 98% and hydrogen peroxide 30% (volumetric ratio 3:7).

I worked with this solution before, but this time I want to use it for cleaning of photolithographic masks (soda-lime glass with chrome layer), which is a standard oparation in photomask cleaning.

Standard usage on piranha etch comprise teflon holder to hold/support mask/wafer/sample. But in some applications tweezers could also be desirable (single wafers instead of batches, small volumes of piranha solution).

My question is: which type of tweezers should I choose for this job (what material), especially for operating large surfaces like wafers or lithographic masks? I did not find consistient and comprehensive info about it.

Teflon tweezers seems sturdy and uneasy to use (manipulating glass mask).

Stainless steel could be susceptible for corrosion. Has anyone had experience with it?

Stainless steel coated with PTFE seems viable, but what about scratching PTFE and exposing stainless steel to corrosion?

Maybe some other materials could be used for the job?

I will appreciate any feedback.

Sincerely,

Grzegorz