[labnetwork] Deep anisotropic etching of SiO2

[Michael Huff]

It can be done, but it is an expensive process and requires a thick nickel hard mask.

See attached paper:



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> On Jan 18, 2023, at 4:23 PM, Ningzhi Xie <nzxie at uw.edu> wrote:
> 
>  Dear college,
> 
> We want to perform a highly anisotropic, very deep (~500um) etching of SiO2 with a vertical side wall. On top of the SiO2 is nanostructures protected by photoresist. The etch depth needs to be controlled with a precision of 20% (we are thinking of using another  material as the substrate underneath the SiO2 layer, which acts as an etch-stopper). The structure and dimensions are shown in the attached image. It would be very helpful if anyone has any idea of this kind of etching (either dry and wet chemical etch is fine).
> 
> Thank you very much.
> 
> Best regards,
> Ningzhi Xie
> Department of Electrical and Computer Engineering
> University of Washington
> <SiO_etch.png>_______________________________________________
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