Process Hierarchy

  Anisotropic wet etch
Process characteristics:
Aspect ratio
Specify preferred aspect ratio (if known) of etch process. Aspect ratio is defined as (etch depth)/(undercut).
Aspect ratio
Specify preferred aspect ratio (if known) of etch process. Aspect ratio is defined as (etch depth)/(undercut).
unconstrained
Depth
Depth to etch in material.
Depth
Depth to etch in material.
unconstrained
Etchant
Specify wet etchant (if known).
Etchant
Specify wet etchant (if known).
Material
Material to be etched.
Material
Material to be etched.
Minimum feature size (masked)
The dimension of the smallest masked feature to be protected during the etch.
Minimum feature size (masked)
The dimension of the smallest masked feature to be protected during the etch.
unconstrained
Minimum feature size (open)
The dimension of the smallest unmasked (open) feature to be etched.
Minimum feature size (open)
The dimension of the smallest unmasked (open) feature to be etched.
unconstrained
Sides processed both
Equipment
Comments:
  • This process exploits the fact that certain chemical solutions (e.g., KOH) exhibit anisotropic etch rates in single crystals (e.g., silicon). It is a useful process to make structures with well-controlled undercutting, and is also well suited for etching completely through substrates. Both sides of the substrate are typically exposed to the etchant.