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NanoFab Tool: SPTS microEtch Hydrofluoric Acid Vapor Etcher

Photograph of the SPTS Etch hydrofluoric acid vapor etcher
Photograph of the SPTS Etch hydrofluoric acid vapor etcher

The SPTS µEtch is a single wafer hydrofluoric acid vapor etcher used to release silicon microstructures in microelectromechanical systems (MEMS) devices. It uses a combination of liquid hydrofluoric acid and alcohol to create a vapor that isotropically etches silicon dioxide without etching silicon and without damaging fragile suspended structures. The tool is capable of creating microscale and nanoscale silicon structures that are freely suspended by etching a sacrificial layer of silicon dioxide underneath the silicon device layer on substrates from small pieces up to 200 mm wafers.


  • Programmable logic controller (PLC) recipe system for precise control of etch parameters.
  • Isotropic etching of silicon dioxide without etching silicon.

Usage Information

Supported Sample Sizes

  • Maximum wafer diameter: 200 mm (8 in).
  • Small pieces supported: Yes.

Typical Applications

  • Microelectromechanical systems (MEMS).
  • Nanoelectromechanical systems (NEMS).
  • Accelerometers.
  • Inkjet heads.
  • Pressure sensors.
  • Releasing fragile structures such as membranes and cantilevers.
Created June 22, 2014, Updated February 24, 2023