Specific Process Knowledge/Etch/DRIE-Pegasus/nanoetch/nano10

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The nano1.0 recipe

Recipe nano1.0

Recipe	Gas	C4F8 38 sccm, SF6 52 sccm
	Pressure	4 mTorr, Strike 3 secs @ 15 mTorr
	Power	800 W CP, 50 W PP
	Temperature	10 degs
	Hardware	100 mm Spacers
	Time	120 secs
Conditions	Run ID	1801
	Conditioning	Sequence: Oxygen clean, MU tests, processes, no oxygen between runs
	Mask	1dfhj10 nm zep etched down to 6dgh4 nm

• The results of the nano1.0 recipe
• 
  The 30 nm trenches
• 
  The 60 nm trenches
• 
  The 90 nm trenches
• 
  The 120 nm trenches
• 
  The 150 nm trenches
• File:C4F8 52 sccm, SF6 38 sccm, 4 mTorr, Strike 3 secs @ 15 mTorr, 800 W CP, 50 W PP, 10 degs, 120 secs

Nominal trench line width	'	30	60	90	120	150	Avg	Std
Etch rates	nm/min	239	281	306	320	328	295	36
Sidewall angle	degs	93	94	93	92	93	93	1
CD loss	nm/edge	-1	-5	-11	-9	-32	-11	12
CD loss foot	nm/edge	-1	-5	-11	-9	-2	-5	5
Bowing		41	33	29	30	22	31	7
Curvature		-51	-50	-43	-39	-42	-45	5
zep	nm/min						46

Comments

The process looks to be too etch aggressive, not enough passivation. Consider any or all of the following:

• Decreasing the wafer temperature (make more passivant)
• Increasing C4F8 flow (make more passivant)
• Increasing platen power (make more directional)
• Decreasing coil power (make less etch-aggressive and more directional.

Also, if the tool has Short Funnel and 5mm spacers fitted, it may be too close to the plasma - previous good nano-scale etch result was achieved with Long Funnel and 100mm spacers.

The conditions are similar to the nano-etch conditions for acceptance process C:

	Etch
Gas Flow (sccm)	SF6 38 + C4F8 70
Pressure (mT)	4
APC angle (%)	33.2
Coil power (W)	450
Matching (Forward/ Load)	L/ 33 & T/ 43
HF Platen power (W)	100
Matching (Forward/ Load)	L/ 49 & T/ 53
Time	01:30
Hardware configuration	150mm Long funnel, with baffle & 100mm spacers
APC Gain	7.5 (default)
Platen Temperature	10°C

The highlighted sections are the main differences between the Process C conditions Vs new Imprint Trenches conditions: all of the changes would push the process to be more passivant, less etch aggressive and more directional.

Is there any reason why these conditions are not suitable for the Imprint Trenches etch?