Nina Feldhofer

I guess there is no easy answer as it depends on how often you are using them, what processes you are performing and the sensitivity of the process.

I often used larger carrier wafers to carry smaller dies or smaller wafers around. Furthermore, for many of my prototype devices I would ensure that there was a blank border or a corner available to access to hold with tweezers.

There are other things you can do such as having a process flow that minimises the number of times you need to pick up samples (e.g., move samples directly from spin coater to hot plate for soft bake), although this can require careful timing control.

Also interested to hear what other RG members recommend.

I am asking because we use vacuum and manual tweezers and just discovered that the vacumm tweezers are leaving particle/dirty prints on the back of the wafer.

really depend on applications and tweezer type.

for microfabrication, usually during the cleaning steps of your devices, you clean the tweezer as well. If it really is some touchy step, then I rinse it with IPA.

When I use my biology tweezers, I always use 70% EtOH, more common for sterilization purpose .

Thank you I will try it with IPA.