The discussion centers on the optimal choice of metal masks for BOE (Buffered Oxide Etch) and HF (Hydrofluoric Acid) etching processes. Participants highlight the use of metals such as Chromium/Gold (Cr/Au), Aluminum (Al), and Nickel (Ni) as potential candidates. The primary concern is the peeling of traditional photoresist due to underetching, which is exacerbated by the isotropic nature of HF etching. A referenced document from MicroChemicals provides additional insights into HF etching techniques.
PREREQUISITESEngineers and technicians involved in semiconductor fabrication, particularly those focused on etching processes and mask design. This discussion is also beneficial for researchers exploring advanced etching techniques.
what about using photoresist?Yinxiao Li said:I am thinking about using a metal mask for BOE or HF etching because I realize that for normal photoresist, it will gradually peel off and affect my results. I don't know which metal is the best--so far, I see people use Cr/Au, Al, and Ni. Anybody knows which metal will give the best result?
Thanks. I am still looking for the best mask that prevents this underetching...leright said:I think the reason it peels is because of underetching (the HF etches underneath the resist as well, since it is an isotropic etchant). See this document for tips.
http://www.microchemicals.com/technical_information/hf_etching.pdf