Most Expected Presenter Final Report Of Wafer Cleaning Seminar 2007

The Final Report of Wafer Cleaning Seminar 2007

Time: August 9, 2007 (Thursday)
Venue: River Front Business Hotel
Address:3000 Long Dong Ave. Zhang Jiang, Shanghai, China

Sponsor

Tea-Break Sponsor

Special Speaker

Mainly came from SMIC (SH), GMSC, HHNEC, BCD, ASMC, HEJIAN and Shanghai Beiling, 165

qualified fabs’ engineers of totaled 194 participants joined in the 4th Wafer Cleaning Seminar on

August 9th 2007 in Shanghai--the center of China semiconductor manufacturing industry. As the

result of 139 received questionnaires, we work out their preference and favorites on wafer cleaning

technologies as well as speeches at this seminar.

Who is most expected to present in next year’s Wafer Cleaning Seminar?

18.00%
16.00%
16.00%

14.00%

12.00%

10.00% 9.33%
8.00% 8.00% 8.00%
8.00% 6.67%
6.00% 5.33% 5.33% 5.33%
4.00% 4.00% 4.00% 4.00% 4.00%
4.00% 2.67% 2.67%
2.00% 1.33% 1.33% 1.33% 1.33% 1.33% 1.33%

0.00%

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ZETA® Spray Cleaning System

Extendable, Multi-use Batch Spray Platform

Used By 4 of 5 largest IC Manufacturers

Shanghai - Aug 9, 2007
• All-wetPR strip,
• Post Ash Cleans
• Co, Ni, NiPt Salicide

Copyright © 2007 | FSI International | All Rights Reserved
always thinking // better ®

ZETA® System Installation Base

• FSI is market leader in batch spray processing
• Over 1000 FSI Spray Systems in fabs worldwide
• ZETA® system is the 6th generation spray processor

US, 28%
BEOL, 31%
Asia, 40%

FEOL, 51%

Other, 7% Japan, 12%

Salicide, Europe,
12% 20%

105 ZETA® Systems - Worldwide

ZETA® Chemical Delivery
Variable flow mixing manifold
1. Flexibility of chemistries and
application 8 flow
2. Recipe optimize (flow, concentration, control valves.
temp.) Flow ranges from
3cc – 5000cc/min
3. Precise, reliable flow/ concentration
4. Sequence flexibility

Chemical Blending Capability
dHF 10:1~ 1000:1
SC1 5:1:1~ 300:1:1
SC2 3.2:1:1 ~ 2666:8:1
H2O:H2O2 3.2:1 ~ 320:1
H2O:HCl 26:1 ~ 2666:1
H2O2:H2SO4 1:4 ~ 1:8
H2SO4:HF 500:1 ~ 5000:1


Thermodynamic Considerations
Species Electro-Chemical Reactive with Bulk Reactive with
Potential (eV) Resist (aromatic) Carbonized Resist
CH2 (aliphatic)
Need radicals to attack
highly cross-linked resist
-C-C-
OH
O• (only exist in ----- Y Y
asher)
OH• 2.80 Y Y

HSO4• 2.60 Y Y

O3 2.08 Y N

H2O2 1.78 N N

H2SO5 1.44 Y N

O2 1.23 N N
H2SO5 is more effective than H2O2 because sulfuric acid can both dehydrate and
dissolve short chain polymer fragments


SPM Piranha Chemistry
• SPM H2SO4 + H2O2 + H2O

• “Caro’s Acid,” if formed
H2SO4 + H2O2 H2SO5 + H2O

H2SO4 + H2O2  H2SO5 + H2O  HSO4• + OH－

• “Radicals”, are formed in solution
H2SO5 HSO4 + OH ● ●


Why Higher Temperature is a Key Factor

Higher on-wafer chemical temperature will lead to
more radical formation and higher reactivity
towards the amorphous carbon layer
500

400 New
wet strip
300 process
reaction rate
(arb. units)
200
Standard
100 wet strip
processes
0
100 120 140 160 180 200 220
temperature (°C)

(assumes 205 kJ/mol activation energy for radical formation)

ViPR™ Spray Strip Process
Wafer Temperature of ~200 °C
Catalyst

Temperature indicating labels
protected by 0.7 mm glass wafer
with high temperature epoxy.
(>204 °C on-wafer indicated)


Keys To Increasing Reactivity

• Higher Sulfuric Acid (Caro’s Acid) Concentration
– higher mixing ratio (>4:1) is desired – least water
dilution, but must maintain H2O2 concentration
• Higher Temperature to create more radicals
– Pre-heat sulfuric acid to achieve higher POU mixing
temperature (do not pre-heat H2O2 to avoid premature
H2O2 degradation)
• Increased Reactivity
– Addition of catalysts significantly increase reactivity


Comparison: ZETA® System vs. Wet Bench
55keV, 1E15 As Implant
Immersion ZETA® System
170°C for 30 min ViPR™ Process 13.5 min

Blank coated wafer

Patterned wafer

• Residue remains • All PR removed
• Process is not • Direct comparison
feasible in a wet shows ViPR™ process
bench is more effective


Cycle Time Reduction:
• 105 min (ash+standard wet bench) – 25 min (ViPR™ Process) = 80 min (savings)
• 80 min/(1.2 days x 24 hrs/day x 60 min/hr)
~5 % reduction
in mask layer
manufacturing
cycle time

ViPR™ Process Summary

• All-wet strip is a trend driven by technology which
also provides productivity benefits
• FSI has a production-proven process for all-wet strip
• Benefits:
– Reduce resist removal cycle time from 1.5–3hrs to 0.5hrs.
– Improve overall fab cycle time per mask layer by 3 to 5%
– Eliminate asher induced damage
– Reduce overall material consumption up to 50%
– Lower capital investment by 15 to 33%


Production Performance
4 ZETA® Systems in Logic Production running ViPR™ Processes
customer targeted oxide loss = 2.5Å
60 4
particle delta >65nm

thermal oxide loss (Å)
40
3
20
0 2
-20
1
-40
-60 0
5 5 5 6 6 6 7 7 7 8 8 8 5 5 6 6 7 7 7 8 8 8
tool number tool number

tool #5: ViPR-95 process (5-6 min.) + APM (2min, 70 °C, 1:4:20 )
tools #6-8: ViPR-120 process (5 min.) + APM (2min, 70 °C, 1:4:20)

** FSI BKM APM step will remove 1.5Å less thermal oxide


ViPR™ Process Particle Performance
Delta (>65nm)

60
40
20
0
Delta
-20
-40
-60
M ay20

M ay21

M ay23
M ay24

M ay26

Jun3
Jun3
Jun5

June
J u l1 8

J u l3 1

Aug23
HS02 HS03 HS04 HS05
SPC monitor data from production installation
ViPR 95


ZETA® System Flexibility

ZETA® System

For Silicide Applications


Contact Technology Evolution
As IC design rules shrink:
Junction depth decreases, allowable silicon
consumption decreases, resistivity becomes a
problem
(0.8µm ~ 0.5µm ~ 0.25µm ~ 65µm)
Silicide evolution: WSiX TiSi2 CoSi2 Ni(Pt)Si
- Co gives lower resistivity than Ti
- Ni consumes less Si than Co TiN cap
spacer Co/CoSi2
or Ni/NiSi
gate
n+ poly oxide p+ poly
TiN/TiSi2 TiN Fox
Oxide spacer n+ n+ p+ p+
p-doping STI n-doping


Co Reduction on SiN
1,0E+13
Cobalt residue on Si3N4 (at/cm^2)

Typical
range
for WB
1,04E+12 POR
1,0E+12

2,80E+11

ZETA®
System
1,0E+11 ACP

1,95E+10

1,0E+10
Zeta Std Zeta ACP2 Zeta ACP1

Note: CoSi2 Sheet Resistance was not increased at all.


BKM Chemical Sequences
Metal Strip for Salicide Formation

• Ti / Ni / NiSi SPM(5 min) – (APM, 3 min)

• Ti / Ni(Pt) / Ni(Pt)Si SPM – HPM – SPM – APM

Removes TiN cap Removes Best particle
and unreacted Ni unreacted Pt performance
(patent pending)
No Pt Residues
• Ni(Pt) > 1000Å/min
• Silicon Oxide < 2Å/min
• Silicon Nitride < 2Å/min
• Poly Silicon < 1Å/min

SPM = H2SO4/H2O2 = “piranha;”
APM = NH4OH/H2O2/H2O = “SC1”
HPM = HCl/H2O2

PlatNiStrip™ Process for NiPt film

PlatNiStrip™

Typical nickel strip process will PlatNiStrip™ process in ZETA®
leave Pt residue eliminates Pt stringer residue


Cross Contamination Analysis
(Ti-coated wafers)

average values: 3 wafers per condition, 5 measurements per wafer (n.d.=0 for calc. of average)

K Ca Ti Cr Mn Fe Co Ni Cu Zn
1st run Pre 0.02 0.01 0.03
Post 0.01 0.04 0.01 0.02 0.01
2nd run Pre 0.02 0.01 0.04
Post 0.02 0.05 0.01 0.01 0.02 0.01
3rd run Pre 0.05 0.02 0.02 0.1
Post 0.03 0.02
4th run Pre 0.11 0.08 0.01 0.02 0.07 0.02
Post 0.07 0.01

1st run: 3 monitoring wafers + 22 Ti (1000A)
2nd, 3rd, 4th run: 3monitoring wafers + 22 dummy Si
TXRF (Technos) - x1010 atoms-cm-2 (detection limit ~0.1 depending on species)
(no entry = not detected)


Multiple process flexibility for IC fabrication
• FEOL
– All-Wet Photoresist Strip (ViPR™) Closed Chamber
– Metal Strip for Salicide Formation
(PlatNiStrip™ )
– Contact Clean

• BEOL
– Cu/low-k Post-Ash Clean
– Al/Cu Post Ash Clean (DSP)

• Back End Process
• Wafer Bumping
– Photoresist Strip
– Flux / Oxide Removal

• General
x8 Chemical
– Wafer Reclaim
In one tool
Fresh chemical
By POU mixing

Summary
• ZETA® system's ViPR™ technology for all wet photoresist
removal has been proven in a manufacturing environment.
• ZETA® system is also the most cost effective and lowest
contamination salicide wet processing tool
(metal strip & contact clean)
• The ZETA® system has been shown to be capable of many
FEOL and BEOL of line processes.
• Superior performance is enabled by the use of single pass
chemistry in the batch spray tool
• CoO is low due to efficient use of chemicals and high
throughput


Most Expected Presenter Final Report Of Wafer Cleaning Seminar 2007

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