UNIFORM FINE
PARTICLES
2. Mechanisms of Formation and
applications
Egon Matijević
Mechanisms of Formation
1. Chemical Aspects
2. Physical Aspects
Mechanisms of Formation
1. Chemical Aspects
2. Physical Aspects
IONS
Complexation
PARTICLE FORMING SOLUTES
Reversible Clustering
EMBRYOS
Irreversible Clustering
NUCLEI
Diffusional Growth
NANOSIZE PRIMARY PARTICLES
Coagulation
Diffusional Growth
AMORPHOUS OR
CRYSTALLINE COLLOIDS
MONODISPERSED
COLLOIDS
Aging, Recrystallization
AGGREGATED
COLLOIDS
Formation of
Monodispersed Colloids
by Aggregation of
Nanosize Precursors
CdS
ZnS
SnO2
0.1 µm
CuO
CeO2
0.05 µm
2.0 µm
2.0 µm
Fe3O4
IONS
Complexation
PARTICLE FORMING SOLUTES
Reversible Clustering
EMBRYOS
Irreversible Clustering
NUCLEI
Diffusional Growth
NANOSIZE PRIMARY PARTICLES
Coagulation
Diffusional Growth
AMORPHOUS OR
CRYSTALLINE COLLOIDS
MONODISPERSED
COLLOIDS
Aging, Recrystallization
AGGREGATED
COLLOIDS
Au
1.0 µm
0.1 µm
Concentration
500 sec
700 sec
0.2
0.4
0.6
//
1.2
1200 sec
1.4
Radius, μm
//
1.9
2.0
2.1
Aragonites
CuO
CuO
AlOOH
Applications
The essence of knowledge is,
once you’ve got it, apply it.
Confucius
APPLICATIONS
• Catalysts
• Ceramics
• Pigments
• Medical Diagnostics
• Chemical Mechanical
Polishing
APPLICATIONS
• Catalysts
• Ceramics
• Pigments
• Medical Diagnostics
• Chemical Mechanical
Polishing
APPLICATIONS
• Catalysts
• Ceramics
• Pigments
• Medical Diagnostics
• Chemical Mechanical
Polishing
APPLICATIONS
• Catalysts
• Ceramics
• Pigments
• Medical Diagnostics
• Chemical Mechanical
Polishing
2.0 µm
APPLICATIONS
• Catalysts
• Ceramics
• Pigments
• Medical Diagnostics
• Chemical Mechanical
Polishing
(A)
Barrier Layer. (Ta/TaN)
Dielectric film
Silicon substrate
(B)
(C)
(D)
Dishing
Erosion of ILD
CMP Evaluation of Colloidal Silica at the
Same Particle Number
Polish
raterate
(nm/min)
Polish
(nm/min)
500
5 wt% H2O2 and 1 wt% glycine at pH 4
400
300
200
1
No silica
502
3
100
Particle diameter (nm)
4
200
Polish rate (nm/min)
CMP Evaluation of Colloidal Silica at the
Same Solid Content
700
3 wt% particle loading
600
pH = 4
500
400
300
Cu wafer, 5 wt% H2O2 + 1 wt% glycine
Cu wafer, 5 wt% H2O2 + 1 wt% glycine + 0.125 wt% Cu(NO3)2
Cu disc, 5 wt% H2O2 + 1 wt% glycine
200
100
0
50
100
150
200
250
300
Diameter of silica particles (nm)
350
400
CMP Evaluation of Colloidal Silica at the
Same Solid Content
Polish rate (nm/min)
25
Ta discs
20
3 wt% particle loading
pH= 4
15
10
5
0
0
100
200
300
Particle diameter (nm)
400
CMP Evaluation of Colloidal Silica at the
Same Specific Surface Area
Polish Rate (nm/min)
700
600
500
400
Specific surface area: 1.8 m2/g
300
pH = 4
200
Cu wafer, 5 wt% H2O2 + 1 wt% glycine
Cu disc, 5 wt% H2O2 + 1 wt% glycine
100
0
0
50
100
150
200
Particle Diameter (nm)
250
300
350
CMP Evaluation of Colloidal Silica at the
Same Solid Content
Particle diameter (nm)
Polish rate (nm/min)
480
200
300
50
100
750
600
PH = 4
450
300
Cu wafer, 5 wt% H2O2 + 1 wt% glycine
Cu disc, 5 wt% H2O2 + 1 wt% glycine
Cu wafer, 5 wt% H2O2 + 1 wt% glycine + 0.125 wt% Cu(NO3)2
150
0
30
40
50
60
70
C1/3·d-1/3 (m-1/3)
80
90
Colloidal Particles
Cubic
hematite
(650 nm)
Ellipsoidal
hematite
(450 nm)
Cubic
hematite
coated
with silica
(700 nm)
Ellipsoidal
hematite
coated
with silica
(400 nm)
Silica Particles Coated with Ceria
Si
Ce
SEM and EDX spectra of ceria coated silica particles
Colloidal Particles Coated with Ceria
Nanosized
Ceria
(20 nm)
Cubic
hematite
as core
material
(700 nm)
Spherical
silica as
core
material
(400 nm)
Ellipsoidal
hematite as
core
material
(400 nm)
CMP with Mixed Abrasives on Oxide
Films
Slurry
Appearance
Polish rate (nm/min)
1.5 wt% ceria (Nyacol) at pH 4
~0
3 wt% cubic hematite (700 nm) at
pH 4
17 ± 0
3 wt% silica (400 nm) + 1.5 wt%
ceria at pH 10
22 ± 2
3 wt% ellipsoidal hematite (450 nm)
+ 1.5 wt% ceria (Nyacol) at pH 4
67 ± 2
3 wt% cubic hematite (700nm) +
1.5 wt% ceria (Nyacol) at pH 4
96 ± 19
CMP with Coated Abrasives on Oxide
Films
Slurry
3 wt% colloidal silica (400 nm)
coated with ceria at pH 4
3 wt% silica encased ellipsoidal
hematite (400 nm) coated with
ceria at pH 4
3 wt% silica encased cubic
hematite (700 nm) coated with
ceria at pH 4
Appearance
Aging condition
Polish rate
(nm/min)
Room
temperature
34 ± 3
83 oC
36 ± 4
Room
temperature
120 ± 12
83 oC
119 ± 7
Room
temperature
121 ± 3
83 oC
112 ± 8
Contact Modes for Mixed Abrasives
wafer
Magnified Image of a Fixed Abrasive Pad
Oxide Removal Rates
Modifying the Pad to Increase the Contact
Area of Ceria with the Wafer
Oxide Wafer
Polishing
pad
Cylindrical structures
on the pad
Supplied Ceria
abrasive
particles
ENERGY
1
WAVE LENGTH
108 nm
ENERGY
Surface Free Energy For Constant Volume
102
1
nanoparticles
104
colloids
RADIUS
106
macrosystems
108 nm
ENERGY
107
CELL SI
1 nm
ZE