What kind of material for suction cup is less ESD risk?

Technical Questions
#1

Hi ESD experts,

Good day! Thanks for all the sharing in this group. It all helps lot!

I am writing to ask a question regarding suction pad material, which usually used in ATE(Auto Testing Equipment).

Remark: In ATE, ICs are placed by suction cap during movement(pick and place).

In general, we all know that all the material including suction cap, which contact to IC should use ESD dissipative type.

But in reality, I noticed that this kind of material(ESD dissipative) will also generate static charge on IC’s surface.

I know material of IC (called compound)maybe different from place to place(semiconductor assembly). It’s hard to control compound material.

Therefore, back to suction cup, i am trying to figure out what kind of material for suction cup is less ESD risk?

Kindly advise, thank you.

Bruce

#2

Hi Bruce,
As you stated the tribocharge left on the component varies depending on material make-up and surface texture. Ideally the best suction cup material would be a material that closely resembles the make-up of the component compound minimizing electron transfer during the process. This is most likely not an option.
There are many factors that affect the amount of charge seen on the component at pick-and-place, humidity, pick-and-place speed, material texture, force, resistance of component compound, resistance of suction cup material, etc. As such this is a very difficult question to answer.
In my experience, a more conductive suction cup (~10E5) leaves less charge on the component package than a suction cup at (~10E9). I would suggest completing some experiments with different suction cup resistances, and material make-up to find a cup that meets all your companies requirements.

#3

Hi ChuckM,

Thanks for your detailed suggestion and experience. I need time to verify which material is suitable for us.

Bruce