Dear Adnan,

The exposure of e-beam onto insulating substrate such as quartz will build up surface charging. A conductive layer is required to supress the charging by conducting the charge to the ground. Gold is a good conductive material but depositing gold layer directly onto quartz surface will be problematic. You may need adhesion enhancement material such as NiCr to be deposited onto quartz prior to gold layer. I don't see gold thickness issue here but grounding the gold layer is very important.

Thank you.

rgds,

Khairudin

Hello Adnan,

Could you try a very thin anti-charging layer on top of the PMMA? For instance a

Dear Khairudin -

Thank you very much for your detailed input. I have mentioned, in order to avoide charging I will coat a conductive polymer on top of the PMMA. My main concern is to know whether 100nm Au layer will act as a high back scatterer medium for incoming e-beam during the exposure?

Thank you for the tip regardinig the adhesion, I will probably use Ti as an adhesion layer.

Best regards,

Adnan

Dear Jules,

Thanks you for your input. I have tried "Al" as an anti-charging layer in the past But now I am using a conductive polymer (from All-Resist) as an alternate. As it is much easier to just spin coat rather than thermally depositing Al.

I think there is a confusion in my question.

The pruprpose of depositing Gold layer is not to use it as anti-charging layer but it is actually a need of the required study. So my substrate would be "100nm Au coated Quartz", and hence I am worried that weather gold layer will contribute in huge backscattering while EBL patterning?

Best Regards, Adnan

Dear Adnan,

You could use Monte Carlo simulation by CASINO software to assess the electrons trajectories and backscaterring.

rgds,

Khairudin

Dear Khairudin,

Thanks for your suggestion. I do not have resources for that and this is why I was expecting some experimental input from community. Thank you again.

Best,

Adnan

Hi.

I guess you can use low voltage setting in the e-beam writer to reduce back scattering mechanism. However, the 100nm gold layer seems a little thicker and may add to back scattering. For the conductive layer coating, I have seen recommendations of ~20nm of Au coating (on top of PMMA) as a grounding layer for insulating substrate.

Dear M. Wahiduzzaman,

Thank you very much for your input. I think using lower value of accelerating voltage might be a good choice.

Best regards,

Adnan