Issm 2010-po-o-102 ppt-for_cdrom_final_revised
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G-NumberISSM 2010 1
NiPt SALICIDE Process Optimization for
28nm CMOS Manufacturing
James M.M. Chu (Speaker)Application Dept. ManagerSE Asia/Greater China RegionFSI International
M 2
01
0
G-NumberISSM 2010 2
Si
NiPt Silicide for CMOS
GateStack
NiSiNiSi
STI STIC
on
tact
ele
ctr
od
e
Co
nta
ct e
lec
tro
de NiSi
Source DrainGate
NiSi
NiSi
Scaling
NiSi
65nm
45nm
28nm
G-NumberISSM 2010 3
NiSi Encroachment Defects
65nm node and beyond : Ni(Pt 5-10%) replace Ni for defect control.But … residual surface Pt removal become a challenge !!!
Spiking
Piping
G-NumberISSM 2010 4
MotivationsTo stay with current material (NiPt) and
chemistry (SPM) for SALICIDE formation
To scale NiSi into 28nm CMOS device
To optimize wet selective etch process– Support the residual NiPt removal on the film
thickness and Pt% proposed– Reduce the process cycle time
G-NumberISSM 2010 5
NiPt Salicide ProcessProcess Flow (Fig.1)
Surface preparation: wet + dry in-situ
Metal Dep.: Ni(Pt) + TiN cap main focus of this presentation
1st Anneal (RTP-1): 200-300C range
Selective wet etching main focus of this presentation
2nd Anneal (RTP-2): > 500C
Defect inspection: SEM e-beam BVC inspection
WAT Measurement: Sheet Resistance / Uniformity
G-NumberISSM 2010 6
Pt Reaction ModelCommon Pt reaction model
- Aqua regia base :
Pt + 4NO3- + 8H + Pt(4+) + NO2 + 4H2O
Pt(4+) + 6Cl - + 2H + H2PtCl6
- Hydrochloric acid base :
Pt + 2H2O2 + 4H + Pt(4+) + 4H2O
Pt(4+) + 6Cl - + 2H + H2PtCl6
Sulfuric Acid Peroxide Pt reaction model- Sulfuric acid base (main focus of this presentation)
Pt + H2SO4 + H2O2 Pt(OH)2++ + PtO++ + H2SO3
SilicideAttacked !
Take placeOn
high temperature
G-NumberISSM 2010 7
Batch/SWProcessor Comparison
HT SPM
wafers wafers
Fig.2(a) Batch wafer type
Closed chamber
HT SPM
wafer
Fig.2(b) Single wafer type
Closed chamber
G-NumberISSM 2010 8
A B C
NiPt Thickness
BV
C C
ou
nt
(a.u
.)
NiPt film thickness (same Pt%)
Pt% / NiPt Film Optimization on Rs/BVC
5% Pt 10% PtNiPt Film
BV
C C
ou
nt
(a.u
.)
x15
Low Pt %
Same NiPt film thickness
High Pt %
Fig.3(a) Pt additive on BVC performance Fig. 3(b) NiPt thickness vs. BVC
increasing film thickness
G-NumberISSM 2010 9
NiPt film thickness (same Pt%)
A B C
NiPt Thickness
BV
C C
ou
nt
(a.u
.)
Sh
ee
t R
es
ista
nc
e (
a.u
.)
Linear Program for NiPt film thickness / Pt%
Pt% / NiPt Film Optimization on Rs/BVC
Fig.3(c) Ni thickness vs. Rs Fig.3(d) Linear program for Pt Additiveto NiPt film thickness for BVC and Rs
BVC - - - Rs - - -
G-NumberISSM 2010 10
Process Window - Cycle Time
Low Pt% High Pt%
Batch type HT SPM Baseline
Pt-free
Batch type HT SPMBaseline
Dual CyclesPt-free
Single wafer type
HT SPM
Pt-free Pt-free
NiPt Thickness B
Pro
ces
s t
ime
(a.u
.)Fig. 4 (a) Process time comparison of batch type to single wafer type wet chemical etch processor
Fig.4 (b) Process cycle time improvement
G-NumberISSM 2010 11
Process Window – SW Time
SPM Process time (s)
90 120 150 180 210
A Pt-free Pt-free Pt-free - -
B - Pt-free Pt-free Pt-free -
C - - Pt-free Pt-free Pt-free
High Pt%NiPt Thickness
(Å)
Table 1 Process window of single wafer wet etch processor over various Pt additive and NiPt film thickness
G-NumberISSM 2010 12
a
Process Time
N_Diff
NU variation range 0.45%
b
Process Time
P_Diff
NU variation range 0.35%
d
Process Time
P_Poly
NU variation range 0.35%
c
Process Time
N_Poly
NU variation range 0.49%
Process SelectivityRs Uniformity Variation Range
Fig. 5 Rs Uniformity variation range by different wet etch process times
G-NumberISSM 2010 13
Summary
• Satisfactory Rs/ Rs uniformity performance
• 15x Improvement on NiSi encroachment through BVC count
• 15x Improvement in cycle time with single wafer system
28nm NiPt Salicide process with co-optimization of NiPt film thickness, Pt additive and the complementary wet selective etch processor
Results