Hi David,

what is "Trilogy etch"?

Thanks for suggestion, I will try to use an evaporated cr-mask.

Best regards,
Andrea


> Hi Andrea,
>
> I am not sure if I understand your problem completely, but when using BHF
> it may be best to use a hard mask. Depending upon the thickness of your
> silicon nitride that you would like to etch, you may want to use Trilogy
> etch or a mixture of 80ml 10%HF to 120ml 85% Nitric acid. Obviously both
> of these etchants are serious stuff, but I have had good experience
> etching sputtered Si3N4 using the HF-Nitric etchant and photoresist.
> Remember, trilogy etch also creates HF from NH4F from dissolution in
> water, so treat it the same way that you would treat HF.
>
> Sincerely,
> David Casale