Run Card for FlexFET process

Step 19a Nitride pad etch on implanted S/D wafers

Steps

Notes

Date

Operator

19a.1

Implanted S/D wafers only:

F# 1, 3, 7, 8, 11, 13, 14.

Lam4, recipe 6200 (SF6 and He):

- Measure etch rate: 1170Å/min – 1390Å/min with 17% un-uniformity

- Etch all wafers and manually endpoint when signal drops (leave ~4 sec over etch time)

Profilometer measurements (trenches WITH resist)

	T	C	F	L	R
F#1	8360	8510	8370	8250	8390
F#13	8130	8110	8130	8110	8350

**** See notes below.

12/19/03

Horvath

19a.2

Continue nitride etch in Applied Centura:

Recipe MXP_NITR_ME, 15 sec etch time (targeting ~900A leftover nitride removal)

Etch rate for nitride is ~3800Å/min

Etch rate for Si is ~1200Å/min

Measurements after the etching:

a) ASIQ profilometer trench depth:

F#3: 8510Å (with resist),

2260Å (after removing resist from one die)

F#13: 8210 Å (with resist)

2210Å (after removing resist from one die)

b) Nanospec (program 116: Si on 1510Å oxide) remaining Si thickness:

	T	C	F
F#1	1130	1196	1148	Thin SOI
F#3	989	1025	986	Thin SOI
F#7	1490	1557	1517	Thick SOI
F#11	1050	1104	1063	Thin SOI
F#13	1508	1528	1528	Thick SOI
F#14	1510	1570	1541	Thick SOI

02/04/04

Horvath

**** Notes: Further experiment results showed serious etching un-uniformities between

small and large geometries during Lam4 etching.

According to these results we estimated ~ 900Å and ~250Å leftover nitride

in 0.35um and 1um trenches.

On F#8 we tried to remove the pad nitride in hot phosphoric acid, but the acid

also etched trenches into the exposed Si region

(~250 - 450Å trenches in different dopant regions)

The wafer is no longer available for further processing.