Specific Process Knowledge/Etch/DRIE-Pegasus/Notation

How to read the SPTS notation on process recipes

To understand the SPTS short hand notation on process recipes look at two examples from the etch cycle of Step1 of the Process A shown in bold below:

1. The Platen power has the setting 120 >> 140 (1.5s) 45 - it is to be interpreted as:
   1. In the first 1.5 seconds of the every cycle the platen power has a value that is ramped (indicated by >>) from 120 W initially to 150 W in the end
   2. During the remainder of the cycle the platen power is kept constant at 45 W.
2. The Pressure has the setting 25 (1.5 s) 90 >> 150 - it is to be interpreted as:
   1. In the first 1.5 seconds the pressure is constant at 25 mtorr.
   2. During the remainder of the cycle the pressure has i higher value that is ramped from 90 initially to 150 mtorr in the last etch cycle.

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