Specific Process Knowledge/Etch/DRIE-Pegasus/processC

The 100 mm wafers had an Al mask made by lift-off:

1. 80 nm of spin coated ZEP520A E-beam resist
2. Patterned by E-beam lithograph
3. 20 nm Al deposited and patterned by lift-off
4. ~ 99 % etch load

Process A specifications

Parameter	Specification	Average result
Etch rate (µm/min)	Not specified
Etched depth (µm)	300
Scallop size (nm)	< 30
Profile (degs)	85 +/- 5
Selectivity to resist	Not speicified
Undercut (nm)	< 30
Uniformity (%)	< 3.5
Repeatability (%)	<4

Process A recipe

	Step 1		Step 2
Parameter	Etch	Dep	Etch	Dep
Gas flow (sccm)	SF6 350 (1.5 s) 550	C4F8 200	SF6 350 (1.5 s) 550	C4F8 200
Cycle time (secs)	7.0	4.0	7.0	4.0
Pressure (mtorr)	25 (1.5 s) 90 >> 150	25	25 (1.5 s) 150	25
Coil power (W)	2800	2000	2800	2000
Platen power (W)	120 >> 140 (1.5) 45	0	140 (1.5) 45	0
Cycles	11 (keep fixed)		44 (vary this)
Common	Temperature 20 degs, HBC 10 torr, Short funnel, with baffle & 5mm spacers