Run Card for FlexFET process

Step 20b. Ti etch on Silicided S/D wafers

Steps

Notes

Date

Operator

20b.1

Silicided S/D wafers only:

F# 2, 5, 6, 9, 10, 12.

Photoresist removal in PRS-3000 in order to prevent exposed Ti oxidation in O2 plasma.

Resist completely removed in 10 hours.

04/02/04

Horvath

20b.2

Wet etch in Sink7:

- Etchant: Sulphuric acid at 95C.

- Pre-measured etch rate: approx. 600-700Ǻ/min on

patterned Ti wafer.

- Etch time chart:

Wafer (SOI type)	Etch time (sec)		Etch time (sec)	Over etch time (sec)*
F#2 (Thick)	15	Rinse + dry	12	15
F#5 (thin)	15	Rinse + dry	14	15
F#6 (thin)	15	Rinse + dry	14	15+10+ 25 sec in NH4OH:H2O2:H2O = 1 : 1 : 5 solution
F#9 (Thick)	15	Rinse + dry	13	15
F#10 (Thick)	15	Rinse + dry	27	-
F#12 (thin)	15	Rinse + dry	13	10+15+20+ 10 @ 105C + EKC270 20 min @ 75C

* After the second etch time all the wafers cleared visually. However residues could be seen under SEM on some regions. The third (over)etch time was given to remove those residues. Unfortunately no progress was observed on the wafers.

W#10 looks entirely clean; on other wafers the residue is concentrated mostly on the center and flat parts.

04/05-14/04

Horvath