Specific Process Knowledge/Etch/Wet Silicon Oxide Etch (BHF): Difference between revisions

[[Category: Equipment|Etch Wet Silicon Oxide]]

[[Category: Etch (Wet) bath|Silicon Oxide]]

==Wet Silicon Oxide Etch (BHF, HF and BOE 7:1 Etchant VLSI with Surfactant (wetting agent))==

Silicon oxide can be etched using HF. At DTU Nanolab it is mainly used in a buffered version BHF (premixed). You can find safety datasheets on Kemibrug [http://kemibrug.dk here] The BHF has a more stable etch rate and is more gentle to photoresist due to an almost pH neutral solution which makes photoresist a good masking material for the oxide etch.  

BOE 7:1 Etchant VLSI with Surfactant (BHF with wetting agent) can also be used for etching silicon oxide. This is mainly for etching small holes. If you have wetting problems in BHF try the BOE 7:1 Etchant VLSI with Surfactant. It is also a good idea to wet the sample in water for a few minutes before etching.

Wafers with metals or other materials, not allowed in the dedicated oxide etch baths, can be etched using a '''plastic''' in Fume hood 01 or 02 (Acids/bases) in D-3. Samples with III-V materials (e.g. InP and GaAs) must be etched in Fume hood 07: III-V Avids/bases in D-3.

*Photoresist

*Photoresist  

! 1% HF PP-bath

|2"- 4" wafers or any that fits in a dedicated holder

==Comparing different 40% HF baths==

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! 40% HF PP-bath

! 40% HF Plastic beaker