Specific Process Knowledge/Etch/ICP Metal Etcher

Etching of nanostructures in silicon using the ICP Metal Etcher

s

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 Failed to parse (SVG (MathML can be enabled via browser plugin): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle \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