Specific Process Knowledge/Etch/ICP Metal Etcher

Etching of nanostructures in silicon using the ICP Metal Etcher

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Two recipes have been optimized for the ASE. Their specification is on a 10 % etch load wafer with trenches.

• Shallolr: The shallow etch process will etch a 2 $\mu$m opening down to make a 20 $\mu$m trench.
• Deepetch: The deep etch process will etch a 50 $\mu$m opening down to make a 300 $\mu$m trench.

The standardization procedure on the ASE covers these two etches.

Recipes on the ASE

Shallolr

The shallolr recipe is designed to etch features (with sizes above 1 $\mu$m) in silicon down to a depth that ranges from a few microns to some 50 microns. (If you need to etch deeper use Deepetch or more shallow, see Nanoetches.) It is specified to etch a 2 $\mu$m wide trench down to a depth of 20 $\mu$m on a wafer that has a global/local etch opening density of 10%.

The recipe is given below.

The starting point

Break	Gas	Cl2 20 sccm
	Pressure	2 mTorr, Strike 3 secs @ 5 mTorr
	Power	600 W CP, 200 W PP
	Temperature	20 degs
	Hardware	100 mm Spacers
	Time	15 secs
Main	Gas	Cl2 20 sccm
	Pressure	2 mTorr, Strike 3 secs @ 5 mTorr
	Power	600 W CP, 200 W PP
	Temperature	20 degs
	Hardware	100 mm Spacers
	Time	15 secs

The process runs for 31 cycles (5:56 mins). The fact that it's Bosch process is clear from the scallops on the sidewalls - one should be able to count 31 of them.

• Standardization images of the shallolr recipe
• 
  The profile of a 2 $\mu$m trench
• 
  The profile of a 50 $\mu$m trench