Process Hierarchy

If you are interested in this process, either by itself or as part of a longer processing sequence, please send us email at engineering@mems-exchange.org or call us at (703) 262-5368
  KOH Silicon Etch I
Process characteristics:
Depth
Depth of material removed by etch process
Depth*
Depth of material removed by etch process, must be 0 .. 1000 µm
0 .. 1000 µm
Batch size 25
Etch rate 20 µm/hour
Etchant
Solutions and their concentrations.
 KOH
Material silicon
Selectivity
Primary material removal rate divided by removal rates of secondary materials (i.e., factors by which primary material is removed faster than secondary materials)
 silicon dioxide: 600, silicon nitride: 10000, silicon: 1
Sides processed both
Temperature 60 °C
Wafer size
Wafer size
Equipment Constant temperature bath
Equipment characteristics:
Wafer geometry
Types of wafers this equipment can accept
 1-flat, 2-flat, notched, no-flat
Wafer holder
Device that holds the wafers during processing.
 teflon cassette
Wafer materials
List of wafer materials this tool can accept (not list of all materials, just the wafer itself).
 silicon
Wafer thickness
List or range of wafer thicknesses the tool can accept
 200 .. 1000 µm
Comments:
  • Wafers should not have any organic material (such as photoresist) on them.
  • KOH etch is a bulk silicon etch whose etch rate is very dependent on the orientation of the silicon's crystal planes. This makes it possible to create specific geometries difficult to produce with other micromachining techniques (for example V-grooves).
  • Silicon dioxide or silicon nitride are the preferred masking materials for this etch.
  • Slow etch rate recipe used to maximize silicon to silicon dioxide selectivity.
  • KOH etch is a bulk silicon etch whose etch rate is very dependent on the orientation of the silicon's crystal planes. This makes it possible to create specific geometries difficult to produce with other micromachining techniques (for example V-grooves).
  • Gold will work as a mask for this etch, other metals may work just as well.