Process Hierarchy

  Chromium wet etch
Process characteristics:
Depth
Depth of material removed by etch process
Depth*
Depth of material removed by etch process, must be 0 .. 1 µm
0 .. 1 µm
Batch size 1
Etchant
Solutions and their concentrations.
Cyantek CR-14 (acetic acid/ceric ammonium nitrate [8%:22%])
Mask materials
Materials that can be used to mask etching.
photoresist (G-line), photoresist (I-line) (category)
Material chromium
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)
chromium: 1
Sides processed both
Temperature 25 °C
Wafer size
Wafer size
Equipment Wet etch bench
Equipment characteristics:
Piece dimension
Range of wafer piece dimensions the equipment can accept
1 .. 150 mm
Piece geometry
Geometry of wafer pieces the equipment can accept
rectangular
Piece thickness
Range of wafer piece thickness the equipment can accept
200 .. 1000 µm
Wafer geometry
Types of wafers this equipment can accept
1-flat, 2-flat
Wafer holder
Device that holds the wafers during processing.
teflon boat, teflon carrier
Wafer materials
List of wafer materials this tool can accept (not list of all materials, just the wafer itself).
quartz (fused silica), Pyrex (Corning 7740), silicon on insulator, silicon, ceramic
Wafer thickness
List or range of wafer thicknesses the tool can accept
200 .. 1000 µm