AND
AND
FOR A RESEARCH BASED IC FABRICATION FACILITY
FOR A RESEARCH BASED IC FABRICATION FACILITY
SAMI UR REHMAN
SAMI UR REHMAN
1
1
S A M I U R R E H M A N ( s a m i r e h m a n . b l o g s p o t . c o m )Difference between Si wafer processing
and compound (III/V) wafer processing
Oxidation
Oxidation
Silicon has a
Silicon has a natural ox
natural oxide while
ide while compound semiconductors
compound semiconductors
do not (deposition
do not (deposition required). Compound semiconductor
required). Compound semiconductor
requires epitaxial deposition techniques which are quiet
requires epitaxial deposition techniques which are quiet
expensive!
expensive!
Stability
Stability
Most of these
Most of these compound semiconductors are not stable at
compound semiconductors are not stable at
high temperatures unlike Si. For Si,
high temperatures unlike Si. For Si, one would
one would therefor
therefore make
e make
MOSFET kind of structures.
MOSFET kind of structures.
2
2
S A M I U R R E H M A N ( s a m i r e h m a n . b l o g s p o t . c o m )
Lattice Constants
Lattice Constants
The first and principal
The first and principal diff
difference between a Si
erence between a Si
and a GaAs substrate is the respective lattice
and a GaAs substrate is the respective lattice
const
constants. Crystalline materials (thin
ants. Crystalline materials (thin films) which
films) which
will be deposited on top of such substrates will
will be deposited on top of such substrates will
have to take this into account.
have to take this into account.
Etching
Etching
Compound semiconductors like GaAs also
Compound semiconductors like GaAs also
requires a complex Chlorine based etch process
requires a complex Chlorine based etch process
unlik
unlike Si
e Si (F based
(F based etch).
etch).
Difference between Si wafer processing
and compound (III/V) wafer processing
3
3
S A M I U R R E H M A N ( s a m i r e h m a n . b l o g s p o t . c o m )WHA
WHAT IS
T IS A CL
A CLEAN ROOM?
EAN ROOM?
•
A clean-room or clean room is an environment, typically
A clean-room or clean room is an environment, typically
used in manufacturing and scientific research, that has a low
used in manufacturing and scientific research, that has a low
level of environmental pollutants such as dust,
level of environmental pollutants such as dust,
airborne microbes, aerosol particles and chemical vapors
airborne microbes, aerosol particles and chemical vapors
(Wikipedia)
(Wikipedia)
•
What matters is
What matters is
Particle size
Particle size
and
and
particle number
particle number
•The standard is called: FED-STD-209 E
The standard is called: FED-STD-209 E
•
This standard was cancelled on Nov 2
This standard was cancelled on Nov 2011
011
•Standardizing
Standardizing Agency:
Agency: U.S.
U.S. General
General Services
Services
Administration (GSA)
Administration (GSA)
•
Replaced by ISO 14644-1
Replaced by ISO 14644-1
4
4
S A M I U R R E H M A N ( s a m i r e h m a n . b l o g s p o t . c o m )CLEAN ROOM
CLEAN ROOM
CLEAN ROOM STANDARDS
CLEAN ROOM STANDARDS
Particle Counters
Particle Counters
are used to determine the air quality by counting and sizing the
are used to determine the air quality by counting and sizing the
number of particles in the air.
number of particles in the air.
This information is useful in determining the amount of particles inside a
This information is useful in determining the amount of particles inside a building or
building or
in the ambient air
in the ambient air
It also
It also is useful in
is useful in understa
understanding the cleanliness level in a controlled environmen
nding the cleanliness level in a controlled environmentt
..
5
5
S A M I U R R E H M A N ( s a m i r e h m a n . b l o g s p o t . c o m )Cost Analysis
Cost Analysis
•
Quotations have been sent
Quotations have been sent
•SANCO
SANCO
•
Rough estimat
Rough estimates of the
es of the equipment have been obtained from:
equipment have been obtained from:
6
6
S A M I U R R E H M A N ( s a m i r e h m a n . b l o g s p o t . c o m )CLEAN ROOM
CLEAN ROOM
P
PARTICLE
ARTICLE COUNTE
COUNTERS
RS
Manufacturer
Manufacturer
Capovani Brothers Inc
Capovani Brothers Inc
Model
Model
P
PARTICLE
ARTICLE MEASURMENT
MEASURMENT SYSTEMS
SYSTEMS LPS
LPS A-310
A-310
Price
Price
$
$ 7,350.00
7,350.00 (each)
(each)
Year of
Year of
Manufacture
Manufacture
2001
2001
Dimensions
Dimensions
Width8.750
Width8.750 in
in (22.2
eight7.000 in (17.8 cm)
eight7.000 in (17.8 cm)
(22.2 cm)
cm) Depth18.000
Depth18.000 in
in (45.7
(45.7 cm)
cm) H
H
Weigh
Weight
t
30
30 lb
lb (14
(14 kg)
kg)
Accessories/Othe
Accessories/Othe
r Information
r Information
Maximum Number of Channels =4
Maximum Number of Channels =4
Channel Siz
Channel Sizes= 0.3,
es= 0.3, 0.5, 1.0, 5.0
0.5, 1.0, 5.0 µm
µm
Light Source=HeNe Multimode, Passive Cavity
Light Source=HeNe Multimode, Passive Cavity
$7,350
$7,350
7
7
S A M I U R R E H M A N ( s a m i r e h m a n . b l o g s p o t . c o m )CLEAN ROOM
CLEAN ROOM
P
PARTICLE
ARTICLE COUNTE
COUNTERS
RS
Manufacturer
Manufacturer
Pacific
Pacific Scientific
Scientific
Model
Model
MET
MET ONE
ONE
Price
Price
$
$ 4,250.00
4,250.00
Year of
Year of
Manufacture
Manufacture
2001
2001
Dimensions
Dimensions
Width13.000
Width13.000 in
in (33.0
(33.0 cm)
cm) Depth12.000
Depth12.000 in
in (30.5
(30.5 cm)
cm) Heig
Heig
ht7.000 in (17.8 cm)
ht7.000 in (17.8 cm)
Weight
Weight
30
30 lb
lb (14
(14 kg)
kg)
Accessories/Other
Accessories/Other
Information
Information
Part no.: 331-3-1-AL
Part no.: 331-3-1-AL
Particle size: 0.3 to 10 Micron
Particle size: 0.3 to 10 Micron
$4,250
$4,250
8
8
S A M I U R R E H M A N ( s a m i r e h m a n . b l o g s p o t . c o m )CLEAN ROOM
CLEAN ROOM
A
AIIR
R C
CO
ON
ND
DIIT
TIIO
ON
NE
ER
R/
/A
AIIR
R F
FL
LO
OW
W C
CO
ON
NT
TR
RO
OL
LLE
LER
R
Manufacturer
Manufacturer
Air
Air Control
Control Inc.
Inc.
Model
Model
VLF
VLF CART
CART
Price
Price
$
$ 3,250.00
3,250.00
Y
Year
ear of
of Manufacture
Manufacture
1998
1998
Dimensions
Dimensions
Width
Width
74.000
74.000 in
in (188.0
(188.0 cm)
cm)
Depth
Depth
21.000
21.000 in
in (53.3
(53.3 cm)
cm)
Height
Height 74.000
74.000 in
in (188.0
(188.0 cm)
cm)
Weight
Weight
5,459
5,459 lb
lb (2,476
(2,476 kg)
kg)
Accessories/Other
Accessories/Other
Information
Information
Unit contains a 9W X
Unit contains a 9W X 10H array of
10H array of
stainless steel cubicles (6.25"W x 4"H
stainless steel cubicles (6.25"W x 4"H
x 11"D)
x 11"D)
Blower: (2) EBM's STD
Blower: (2) EBM's STD
Prefilter #: (2) 16 x 20 x 1
Prefilter #: (2) 16 x 20 x 1
Hepa Filter #: (1) 18 x 48 x 3
Hepa Filter #: (1) 18 x 48 x 3
$3,250
$3,250
9
9
S A M I U R R E H M A N ( s a m i r e h m a n . b l o g s p o t . c o m )CLEAN ROOM
CLEAN ROOM
A
AIIR
R C
CO
ON
ND
DIIT
TIIO
ON
NE
ER
R/
/A
AIIR
R F
FL
LO
OW
W C
CO
ON
NT
TR
RO
OL
LLE
LER
R
Manufacturer
Manufacturer
Air
Air Control
Control Inc.
Inc.
Model
Model
AirPod
AirPod
Price
Price
Year of Manufacture
Year of Manufacture
Dimensions
Dimensions
Width:
Width:
AirPod
AirPod I: 62.50”,AirPod II:
AirPod II:
80.50”, AirPod
AirPod III: 104.50”
Height:
Height:
31.00”
Depth:
Depth:
31.00”
Weight
Weight
Weight
Weight (lbs):
(lbs):
AirPod I: 312, AirPod II:
AirPod I: 312, AirPod II:
394, AirPod III: 455
394, AirPod III: 455
Accessories/Other
Accessories/Other
Information
Information
Nominal Air flow: 2500 CFM (3/4 HP), 5000 CFM (3HP),
Nominal Air flow: 2500 CFM (3/4 HP), 5000 CFM (3HP),
4000 CFM (3HP with
4000 CFM (3HP with AD after-filter).
AD after-filter).
Blower Pkg (HP): AirPod I: 2-speed forward curve,
Blower Pkg (HP): AirPod I: 2-speed forward curve,
direct drive; AirPod II & III: Dynamically balanced,
direct drive; AirPod II & III: Dynamically balanced,
non-sparking, motor/blowers. (Optional 2-speed
sparking, motor/blowers. (Optional 2-speed
motor/blower available for AirPod II.)
motor/blower available for AirPod II.)
Electrical: AirP
Electrical: AirPod I, standard: 115/1/60,
od I, standard: 115/1/60, 11.4 amps, 3/4
11.4 amps, 3/4
HP; AirPod II & III, standard: 208-230/460/3/60,
HP; AirPod II & III, standard: 208-230/460/3/60,
7.8-7.2/4 amps, 3 HP; op
7.2/4 amps, 3 HP; optional: 230/1/60 11.7 amps,
tional: 230/1/60 11.7 amps, 3 HP
3 HP..
$3,000
$3,000
10
10
S A M I U R R E H M A N ( s a m i r e h m a n . b l o g s p o t . c o m )IC FABRICATION PHILOSOPHY!
IC FABRICATION PHILOSOPHY!
Deposition
Deposition
Adding layer onto
Adding layer onto waf
wafer!
er!
Adding impurities in
Adding impurities in
wafer!
wafer!
Implantation
Implantation
Removing an added layer!
Removing an added layer!
Etching
Etching
Photolithography
Photolithography
11
11
S A M I U R R E H M A N ( s a m i r e h m a n . b l o g s p o t . c o m )III/V Group ingot production
Similar to the silicon ingot growth process, elemental
Similar to the silicon ingot growth process, elemental
forms of III and V group elements, plus
forms of III and V group elements, plus small quantities
small quantities
of dopant
of dopant material-silic
material-silicon,
on,
tellurium or zinc-are
tellurium or zinc-are reacted at
reacted at
elevated temperatures to
elevated temperatures to
form ingots of doped
form ingots of doped
single-crystal III/V material like GaAs.
crystal III/V material like GaAs.
Quartz Tube
Quartz Tube
Rotating Chuck
Rotating Chuck
Seed Crystal
Seed Crystal
Growing Crystal
Growing Crystal
(boule)
(boule)
RF or Resistance
RF or Resistance
Heating Coils
Heating Coils
Molten Silicon
Molten Silicon
(Melt)
(Melt)
Crucible
Crucible
12
12
S A M I U R R E H M A N ( s a m i r e h m a n . b l o g s p o t . c o m )Photomask Creation
•
The photomask is a copy of the circuit pattern,
drawn on a glass plate coated with a metallic film.
•
The glass plate lets light pass, but the metallic film
does not.
•
Due to increasingly high integration and
miniaturization of the pattern, the size of the
photomask is usually magnified four to ten times
the actual size.
13
13
S A M I U R R E H M A N ( s a m i r e h m a n . b l o g s p o t . c o m )PHOTOLITHOGRAPHY
PHOTOLITHOGRAPHY
Wafer processing consists of a sequence of
additive
additive
and
subtractive
subtractive
steps with
patterning
patterning
!!!!!
oxidation
oxidation
deposition
deposition
ion implantation
ion implantation
etching
lithography
etching
lithography
Lithography
Lithography
refers to the process of transferring a circuit pattern,
refers to the process of transferring a circuit pattern,
embedded on a
embedded on a mask,
mask, to the
to the surface of the
surface of the wafer
wafer
Equipment, materials, and processes needed
Equipment, materials, and processes needed
::
•
A mask (for each
A mask (for each layer to be patterned) with the
layer to be patterned) with the desired pattern
desired pattern
•
A light-sensitive material (called
A light-sensitive material (called
photoresist
photoresist
) covering the wafer so as to receive
) covering the wafer so as to receive
the pattern
the pattern
•
A light source and method of projecting the image
A light source and method of projecting the image of the mask onto the
of the mask onto the
photoresist
photoresist
(“
printer
” or “
projection stepper
” or “
projection scanner
”)
•
A method of “developing” the
photor
photoresist, that is sele
esist, that is selectively removing it from the
ctively removing it from the
regions where it was exposed
regions where it was exposed
Photolithogr
Photolithography is a
aphy is a process analogous to developing film in
process analogous to developing film in a darkroom
a darkroom
14
14
S A M I U R R E H M A N ( s a m i r e h m a n . b l o g s p o t . c o m )PHOTOLITHOGRAPHY STEPS
PHOTOLITHOGRAPHY STEPS
•
1 # PRE BAKE
1 # PRE BAKE THE W
THE WAFER
AFER
Wa
Wafer is preheate
fer is preheated to about 200
d to about 200 - 250 degrees C in
- 250 degrees C in a
a
bake
bake
oven
oven
. The purpose o
. The purpose of this step is to ensure that the
f this step is to ensure that the waf
wafer is
er is
completely dry. Any moisture on the wafer surface would
completely dry. Any moisture on the wafer surface would
interf
interfere with the
ere with the photolithograph
photolithography process, causing it to
y process, causing it to yield
yield
poor results.
poor results.
15
15
S A M I U R R E H M A N ( s a m i r e h m a n . b l o g s p o t . c o m )PHOTOLITHOGRAPHY STEPS
PHOTOLITHOGRAPHY STEPS
•
2 # PHOTORESIST APPLICATION AND SPINNING
2 # PHOTORESIST APPLICATION AND SPINNING
•
The wafer is placed on the wafer chuck in the center of the
The wafer is placed on the wafer chuck in the center of the
Photoresist Spinner
Photoresist Spinner
. After properly adjusting the
. After properly adjusting the waf
wafer on t
er on the
he
spinner
spinner, photo
, photo resist material is applied
resist material is applied onto the surface of
onto the surface of
the wafer and is spun so that photo resist evenly distributes
the wafer and is spun so that photo resist evenly distributes
on the wafer
on the wafer
•
Using the Nitrogen Gun,
Using the Nitrogen Gun,
now the wafer surface is
now the wafer surface is
Blown to remove any dust
Blown to remove any dust
particles.
particles.
16
16
S A M I U R R E H M A N ( s a m i r e h m a n . b l o g s p o t . c o m )PHOTOLITHOGRAPHY STEPS
PHOTOLITHOGRAPHY STEPS
Photoresist Raw Materials
Photoresist Raw Materials
http://www
http://www.mitsuichemicals.com/photoresist.htm
.mitsuichemicals.com/photoresist.htm
17
17
S A M I U R R E H M A N ( s a m i r e h m a n . b l o g s p o t . c o m )PHOT
PHOTOLITHOGRAPHY
OLITHOGRAPHY
STEPS
STEPS
Photo resist properties
Photo resist properties
http://www.cleanroom.byu.edu/photoresists.phtml
http://www.cleanroom.byu.edu/photoresists.phtml
18
18
S A M I U R R E H M A N ( s a m i r e h m a n . b l o g s p o t . c o m )Photoresist Spin Coater
Vacuum
Vacuum
PR
PR
EBR
EBR
Wafer
Wafer
Chuck
Chuck
Water
Water
Sleeve
Sleeve
Drain
Drain
Exhaust
Exhaust
19
19
S A M I U R R E H M A N ( s a m i r e h m a n . b l o g s p o t . c o m )Photoresist Applying
Spindle
Spindle
PR dispenser
PR dispenser
nozzle
nozzle
Chuck
Chuck
Wafer
Wafer
To vacuum pump
To vacuum pump
20
20
S A M I U R R E H M A N ( s a m i r e h m a n . b l o g s p o t . c o m )Photoresist Suck Back
Spindle
Spindle
To vacuum pump
To vacuum pump
PR dispenser nozzle
PR dispenser nozzle
Chuck
Chuck
PR suck back
PR suck back
Wafer
Wafer
21
21
S A M I U R R E H M A N ( s a m i r e h m a n . b l o g s p o t . c o m )Photoresist Spin Coating
Spindle
Spindle
To vacuum pump
To vacuum pump
PR dispenser nozzle
PR dispenser nozzle
Chuck
Chuck
PR suck back
PR suck back
Wafer
Wafer
22
22
S A M I U R R E H M A N ( s a m i r e h m a n . b l o g s p o t . c o m )Photoresist Spin Coating
Spindle
Spindle
To vacuum pump
To vacuum pump
PR dispenser nozzle
PR dispenser nozzle
Chuck
Chuck
PR suck back
PR suck back
Wafer
Wafer
23
23
S A M I U R R E H M A N ( s a m i r e h m a n . b l o g s p o t . c o m )Photoresist Spin Coating
Spindle
Spindle
To vacuum pump
To vacuum pump
PR dispenser nozzle
PR dispenser nozzle
Chuck
Chuck
PR suck back
PR suck back
Wafer
Wafer
24
24
S A M I U R R E H M A N ( s a m i r e h m a n . b l o g s p o t . c o m )Photoresist Spin Coating
Spindle
Spindle
To vacuum pump
To vacuum pump
PR dispenser nozzle
PR dispenser nozzle
Chuck
Chuck
PR suck back
PR suck back
Wafer
Wafer
25
25
S A M I U R R E H M A N ( s a m i r e h m a n . b l o g s p o t . c o m )Photoresist Spin Coating
Spindle
Spindle
To vacuum pump
To vacuum pump
PR dispenser nozzle
PR dispenser nozzle
Chuck
Chuck
PR suck back
PR suck back
Wafer
Wafer
26
26
S A M I U R R E H M A N ( s a m i r e h m a n . b l o g s p o t . c o m )Photoresist Spin Coating
Spindle
Spindle
To vacuum pump
To vacuum pump
PR dispenser nozzle
PR dispenser nozzle
Chuck
Chuck
PR suck back
PR suck back
Wafer
Wafer
27
27
S A M I U R R E H M A N ( s a m i r e h m a n . b l o g s p o t . c o m )Photoresist Spin Coating
Spindle
Spindle
To vacuum pump
To vacuum pump
PR dispenser nozzle
PR dispenser nozzle
Chuck
Chuck
PR suck back
PR suck back
Wafer
Wafer
28
28
S A M I U R R E H M A N ( s a m i r e h m a n . b l o g s p o t . c o m )Photoresist Spin Coating
Spindle
Spindle
To vacuum pump
To vacuum pump
PR dispenser nozzle
PR dispenser nozzle
Chuck
Chuck
PR suck back
PR suck back
Wafer
Wafer
29
29
S A M I U R R E H M A N ( s a m i r e h m a n . b l o g s p o t . c o m )Photoresist Spin Coating
Spindle
Spindle
To vacuum pump
To vacuum pump
PR dispenser nozzle
PR dispenser nozzle
Chuck
Chuck
PR suck back
PR suck back
Wafer
Wafer
30
30
S A M I U R R E H M A N ( s a m i r e h m a n . b l o g s p o t . c o m )Edge Bead Removal
Spindle
Spindle
To vacuum pump
To vacuum pump
Chuck
Chuck
Wafer
Wafer
Solvent
Solvent
31
31
S A M I U R R E H M A N ( s a m i r e h m a n . b l o g s p o t . c o m )Edge Bead Removal
Spindle
Spindle
To vacuum pump
To vacuum pump
Chuck
Chuck
Wafer
Wafer
Solvent
Solvent
32
32
S A M I U R R E H M A N ( s a m i r e h m a n . b l o g s p o t . c o m )Optical Edge Bead Removal
Exposure
Spindle
Spindle
Chuck
Chuck
Wafer
Wafer
Photoresist
Photoresist
Light source
Light source
Light beam
Light beam
Exposed
Exposed
Photoresist
Photoresist
33
33
S A M I U R R E H M A N ( s a m i r e h m a n . b l o g s p o t . c o m )PHOTOLITHOGRAPHY STEPS
PHOTOLITHOGRAPHY STEPS
•
3 # SOFT BAKE
3 # SOFT BAKE
•
The wafer is placed into the
The wafer is placed into the
Soft-Bake Oven
Soft-Bake Oven
for 30 minutes.
for 30 minutes.
•The purpose of
The purpose of the soft bake is to semi-harden
the soft bake is to semi-harden
the
the photoresis
photoresistt
34
34
S A M I U R R E H M A N ( s a m i r e h m a n . b l o g s p o t . c o m )Methods of Soft Bake
•
Hot plates
Hot plates
•
Convection oven
Convection oven
•Infrared oven
Infrared oven
•Microwave oven
Microwave oven
35
35
S A M I U R R E H M A N ( s a m i r e h m a n . b l o g s p o t . c o m )Baking Systems
Heater
Heater
Vacuum
Vacuum
Wafer
Wafer
Heater
Heater
Heated N
Heated N
2
2
Wafers
Wafers
MW Source
MW Source
Vacuum
Vacuum
Wafer
Wafer
Photoresist
Photoresist
Chuck
Chuck
Hot
Hot plate
plate
Convection
Convection oven
oven
Microwa
Microwave
ve oven
oven
36
36
S A M I U R R E H M A N ( s a m i r e h m a n . b l o g s p o t . c o m )Hot Plates
•
Widely used in the industry
Widely used in the industry
•Back side heating, no surface
Back side heating, no surface
“crust”
•
In-line track system
In-line track system
Heater
Heater
Wafer
Wafer
37
37
S A M I U R R E H M A N ( s a m i r e h m a n . b l o g s p o t . c o m )PHOTOLITHOGRAPHY STEPS
•
4 # EXPOSE TO UV LIGHT
4 # EXPOSE TO UV LIGHT
•
carefully place the wafer on the wafer chuck of the Aligner
carefully place the wafer on the wafer chuck of the Aligner
•When the wafer has been
When the wafer has been properly aligned to the mask,
properly aligned to the mask,
expose it to UV light
expose it to UV light
•
the exposure time should be
the exposure time should be set according to the particular
set according to the particular
type of photo resist and wattage of the bulb being used
type of photo resist and wattage of the bulb being used..
38
38
S A M I U R R E H M A N ( s a m i r e h m a n . b l o g s p o t . c o m )Alignment
P-Well
P-Well
n+
n+
n+
n+
Polysilicon
Polysilicon
Photoresist
Photoresist
Gate Mask
Gate Mask
39
39
S A M I U R R E H M A N ( s a m i r e h m a n . b l o g s p o t . c o m )Exposure
Gate Mask
Gate Mask
P-Well
P-Well
n+
n+
n+
n+
Polysilicon
Polysilicon
Photoresist
Photoresist
40
40
S A M I U R R E H M A N ( s a m i r e h m a n . b l o g s p o t . c o m )Ready for Post Exposure Bake
P-Well
P-Well
n+
n+
n+
n+
Polysilicon
Polysilicon
Photoresist
Photoresist
41
41
S A M I U R R E H M A N ( s a m i r e h m a n . b l o g s p o t . c o m )PHOTOLITHOGRAPHY STEPS
PHOTOLITHOGRAPHY STEPS
•
5 # DEVELOPMENT
5 # DEVELOPMENT
•
The type of developer solution used is determined by the
The type of developer solution used is determined by the
type of photoresist chosen.
type of photoresist chosen.
•
Then we check the developer for the recommended
Then we check the developer for the recommended
development time. Typically
development time. Typically, this
, this will be
will be around 30 seconds
around 30 seconds
•Then the wafer is immersed in the developer and
Then the wafer is immersed in the developer and agitate
agitate
mildly until the time has expired.
mildly until the time has expired.
•
Finally the wafer is rinsed with io
Finally the wafer is rinsed with ionized wate
nized waterr
42
42
S A M I U R R E H M A N ( s a m i r e h m a n . b l o g s p o t . c o m )Schematic of a Spin Developer
Schematic of a Spin Developer
Vacuum
Vacuum
Developer
Developer
Wafer
Wafer
Chuck
Chuck
Water
Water
sleeve
sleeve
Drain
Drain
DI water
DI water
43
43
S A M I U R R E H M A N ( s a m i r e h m a n . b l o g s p o t . c o m )Applying Development
Solution
Spindle
Spindle
Chuck
Chuck
Wafer
Wafer
Exposed
Exposed
Photoresist
Photoresist
Development solution
Development solution
dispenser nozzle
dispenser nozzle
To vacuum pump
To vacuum pump
44
44
S A M I U R R E H M A N ( s a m i r e h m a n . b l o g s p o t . c o m )Applying Development
Solution
Spindle
Spindle
To vacuum pump
To vacuum pump
Chuck
Chuck
Wafer
Wafer
Exposed
Exposed
Photoresist
Photoresist
45
45
S A M I U R R E H M A N ( s a m i r e h m a n . b l o g s p o t . c o m )Spindle
Spindle
To vacuum
To vacuum
pump
pump
Chuck
Chuck
Wafer
Wafer
Patterned
Patterned
photoresist
photoresist
Developer Spin Off
Developer Spin Off
Edge PR removed
Edge PR removed
46
46
S A M I U R R E H M A N ( s a m i r e h m a n . b l o g s p o t . c o m )DI Water Rinse
Spindle
Spindle
To vacuum
To vacuum
pump
pump
Chuck
Chuck
Wafer
Wafer
DI water
DI water
dispenser
dispenser
nozzle
nozzle
47
47
S A M I U R R E H M A N ( s a m i r e h m a n . b l o g s p o t . c o m )Spin Dry
Spindle
Spindle
To vacuum pump
To vacuum pump
Chuck
Chuck
Wafer
Wafer
48
48
S A M I U R R E H M A N ( s a m i r e h m a n . b l o g s p o t . c o m )Ready For Hard Bake
Spindle
Spindle
Chuck
Chuck
Wafer
Wafer
49
49
S A M I U R R E H M A N ( s a m i r e h m a n . b l o g s p o t . c o m )Development Profiles
PR
PR
PR
PR
Substrate
Substrate
Substrate
Substrate
PR
PR
Substrate
Substrate
PR
PR
Substrate
Substrate
Normal Development
Normal Development
Under
Under Development
Development
Over
Over Development
Development
Incomplete Development
Incomplete Development
50
50
S A M I U R R E H M A N ( s a m i r e h m a n . b l o g s p o t . c o m )Developer Solution
•
+PR normally uses weak base
+PR normally uses weak base
solution
solution
•
The most commonly used one is
The most commonly used one is
the tetramethyl ammonium
the tetramethyl ammonium
hy
hydride, or TMAH
dride, or TMAH ((CH
((CH
3
3
))
4
4
NOH).
NOH).
51
51
S A M I U R R E H M A N ( s a m i r e h m a n . b l o g s p o t . c o m )Developer Solutions
Positive
Positive PR
PR
Negative
Negative PR
PR
Developer
Developer
TMAH
TMAH
Xylene
Xylene
Rinse
Rinse
DI
DI W
Water
ater
n-Butylacetate
n-Butylacetate
52
52
S A M I U R R E H M A N ( s a m i r e h m a n . b l o g s p o t . c o m )PHOTOLITHOGRAPHY STEPS
PHOTOLITHOGRAPHY STEPS
•
6 # HARD BAKE THE WAFER
6 # HARD BAKE THE WAFER
•
The wafer is placed into
The wafer is placed into the Hard Bake oven now which
the Hard Bake oven now which
should be preheated to between 120-130 degrees C.
should be preheated to between 120-130 degrees C.
•The wafers should remain in the hard bake oven for 30
The wafers should remain in the hard bake oven for 30
minutes. This prepares the wafer for the next processing step.
minutes. This prepares the wafer for the next processing step.
53
53
S A M I U R R E H M A N ( s a m i r e h m a n . b l o g s p o t . c o m )T
Types
ypes of Ph
of Photoresist
otoresist
Negative Photoresist
Negative Photoresist
•
Becomes insoluble
Becomes insoluble
after exposure
after exposure
•
When developed,
When developed,
the unexposed
the unexposed
parts dissolved.
parts dissolved.
•
Cheaper
Cheaper
Positive
Positive Photoresis
Photoresistt
•
Becomes soluble
Becomes soluble
after exposure
after exposure
•
When developed,
When developed,
the exposed parts
the exposed parts
dissolved
dissolved
•
Better resolution
Better resolution
54
54
S A M I U R R E H M A N ( s a m i r e h m a n . b l o g s p o t . c o m )Mask/reticle
Mask/reticle
Exposure
Exposure
After
After
Development
Development
Negative
Negative
Photoresist
Photoresist
UV light
UV light
Positive
Positive
Photoresist
Photoresist
Substrate
Substrate
Substrate
Substrate
Substrate
Substrate
Photoresist
Photoresist
Negative and Positive Photoresists
Negative and Positive Photoresists
Substrate
Substrate
Photoresist
Photoresist
55
55
S A M I U R R E H M A N ( s a m i r e h m a n . b l o g s p o t . c o m )Comparison of Photoresists
-PR
PR
Film
Film
+ PR
+ PR
Film
Film
Substrate
Substrate
Substrate
Substrate
56
56
S A M I U R R E H M A N ( s a m i r e h m a n . b l o g s p o t . c o m )Wafer In
Hot Plate
Hot Plate
Developer
Developer
dispenser
dispenser
Track
Track
Hot Plate
Hot Plate
Spin Station
Spin Station
Stepper
Stepper
Track Robot
Track Robot
57
57
S A M I U R R E H M A N ( s a m i r e h m a n . b l o g s p o t . c o m )Pre-bake and Primer Vapor
Coating
Hot Plate
Hot Plate
Developer
Developer
dispenser
dispenser
Track
Track
Hot Plate
Hot Plate
Spin Station
Spin Station
Stepper
Stepper
Track Robot
Track Robot
58
58
S A M I U R R E H M A N ( s a m i r e h m a n . b l o g s p o t . c o m )Photoresist Spin Coating
Hot Plate
Hot Plate
Developer
Developer
dispenser
dispenser
Track
Track
Hot Plate
Hot Plate
Spin Station
Spin Station
Stepper
Stepper
Track Robot
Track Robot
59
59
S A M I U R R E H M A N ( s a m i r e h m a n . b l o g s p o t . c o m )Soft Bake
Hot Plate
Hot Plate
Developer
Developer
dispenser
dispenser
Track
Track
Hot Plate
Hot Plate
Spin Station
Spin Station
Stepper
Stepper
Track Robot
Track Robot
60
60
S A M I U R R E H M A N ( s a m i r e h m a n . b l o g s p o t . c o m )Alignment and Exposure
Hot Plate
Hot Plate
Developer
Developer
dispenser
dispenser
Track
Track
Hot Plate
Hot Plate
Spin Station
Spin Station
Stepper
Stepper
Track Robot
Track Robot
61
61
S A M I U R R E H M A N ( s a m i r e h m a n . b l o g s p o t . c o m )Post Exposure Bake (PEB)
Hot Plate
Hot Plate
Developer
Developer
dispenser
dispenser
Track
Track
Hot Plate
Hot Plate
Spin Station
Spin Station
Stepper
Stepper
Track Robot
Track Robot
62
62
S A M I U R R E H M A N ( s a m i r e h m a n . b l o g s p o t . c o m )Development
Hot Plate
Hot Plate
Developer
Developer
dispenser
dispenser
Track
Track
Hot Plate
Hot Plate
Spin Station
Spin Station
Stepper
Stepper
Track Robot
Track Robot
63
63
S A M I U R R E H M A N ( s a m i r e h m a n . b l o g s p o t . c o m )Hard Bake
Hot Plate
Hot Plate
Developer
Developer
dispenser
dispenser
Track
Track
Hot Plate
Hot Plate
Spin Station
Spin Station
Stepper
Stepper
Track Robot
Track Robot
64
64
S A M I U R R E H M A N ( s a m i r e h m a n . b l o g s p o t . c o m )Wafer out
Hot Plate
Hot Plate
Developer
Developer
dispenser
dispenser
Track
Track
Hot Plate
Hot Plate
Spin Station
Spin Station
Stepper
Stepper
Track Robot
Track Robot
65
65
S A M I U R R E H M A N ( s a m i r e h m a n . b l o g s p o t . c o m )Resolution
•
The achievable, repeatable
The achievable, repeatable
minimum feature size
minimum feature size
•
Determined by the wavelength of
Determined by the wavelength of
the light and the numerical
the light and the numerical
aperture of the system. The
aperture of the system. The
resolution can be expressed as
resolution can be expressed as
66
66
S A M I U R R E H M A N ( s a m i r e h m a n . b l o g s p o t . c o m )Resolution
NA
NA
K
K
R
R
1
• K
1
1
is the
is the syst
system constant
em constant
is the wavelength of the light
is the wavelength of the light
NA
= 2
= 2
r
o
/D
, is the numerical aperture
, is the numerical aperture
67
67
S A M I U R R E H M A N ( s a m i r e h m a n . b l o g s p o t . c o m )Numerical Aperture
• NA
is the ability of a lens to collect diffracted
is the ability of a lens to collect diffracted
light
light
•
NA = 2 r
0
/ D
– r
0
: radius of the lens
: radius of the lens
–
D
= the distance of the object from the lens
= the distance of the object from the lens
•
Lens with larger
Lens with larger
NA
can capture higher order
can capture higher order
of diffracted light and generate sharper image.
of diffracted light and generate sharper image.
68
68
S A M I U R R E H M A N ( s a m i r e h m a n . b l o g s p o t . c o m )To Improve Resolution
•
Increase NA
Increase NA
•
Larger lens, could be
Larger lens, could be too expensiv
too expensive and
e and unpractic
unpractical
al
•Reduce DOF and
Reduce DOF and cause fabrication difficulties
cause fabrication difficulties
•
Reduce wavelength
Reduce wavelength
•
Need develop light source, PR and equipment
Need develop light source, PR and equipment
•Limitation for reducing wavelength
Limitation for reducing wavelength
•
UV to DUV, to EUV, and to X-Ray
UV to DUV, to EUV, and to X-Ray
69
69
S A M I U R R E H M A N ( s a m i r e h m a n . b l o g s p o t . c o m )Depth of focus
•
The range that light is
The range that light is in focus and can achieve good resolution of
in focus and can achieve good resolution of
projected image
projected image
•
Depth of focus can be expressed as:
Depth of focus can be expressed as:
2
2
)
(
2
NA
NA
K
K
D
DO
OF
F
70
70
S A M I U R R E H M A N ( s a m i r e h m a n . b l o g s p o t . c o m )Depth of Focus
•
Smaller numerical aperture, larger DOF
Smaller numerical aperture, larger DOF
•
Disposable cameras with very small lenses
Disposable cameras with very small lenses
•Almost everything is in focus
Almost everything is in focus
•
Bad resolution
Bad resolution
•
Prefer reduce wavelength than increase
Prefer reduce wavelength than increase
NA
to improve
to improve
resolution
resolution
•
High resolution, small DOF
High resolution, small DOF
•Focus at the middle of
Focus at the middle of PR layer
PR layer
71
71
S A M I U R R E H M A N ( s a m i r e h m a n . b l o g s p o t . c o m )Photolithography
MASK ALLIGNER
MASK ALLIGNER
Karl Suss MA-6 Mask Aligner
Description
Description
Can handle Si and Compound
semiconductor wafers
Up to 6"in size
240 nm to 365 nm wavelength
.
1:1 exposure system
Maximum wafer thickness:
4.3mm
Alignment accuracy of +-0.5um
$69,000
$69,000
72
72
S A M I U R R E H M A N ( s a m i r e h m a n . b l o g s p o t . c o m )Photolithography
MASK ALLIGNER
MASK ALLIGNER
Mask-aligner EV-420
Mask-aligner EV-420
Description
Description
Contact mask-aligner for
Contact mask-aligner for
optical lithography
optical lithography
Double side exposure
Double side exposure
Lamp power
Lamp power
: 350 W
: 350 W
Illumination spectrum: no
Illumination spectrum: no
filters
filters
73
73
S A M I U R R E H M A N ( s a m i r e h m a n . b l o g s p o t . c o m )Photolithography
MASK ALLIGNER
MASK ALLIGNER
Manufacturer
SussMicrotec
Manufacturer
SussMicrotec
Model
Model
BLE
BLE RESPECT
RESPECT 600
600
Weig
Weight
ht
880
880 lb
lb (399
(399 kg)
kg)
Accessories/ Other Specifications
Accessories/ Other Specifications
400 V 16 A 50 Hz
400 V 16 A 50 Hz
System features
Programmable controller
Programmable controller
PC with windows NT4SP6 and
PC with windows NT4SP6 and
applications program Respect
applications program Respect
1.0b0087/1.1b0002
1.0b0087/1.1b0002
Touch screen
Touch screen
RS 232 Interface
RS 232 Interface
Vacuum monitoring
Vacuum monitoring
External cabinet exhaust
External cabinet exhaust
connection
connection
Automatic exhaust control
Automatic exhaust control
Media control panel
Media control panel
Silicon and compound
Silicon and compound
semiconductor wafers
semiconductor wafers
74
74
S A M I U R R E H M A N ( s a m i r e h m a n . b l o g s p o t . c o m )Photolithography
SPINNERS
SPINNERS
Solitec 5100 LVT
Solitec 5100 LVT
•
Provides spin processing of
Provides spin processing of single wafers/substrates
single wafers/substrates
of up to 22
of up to 225mm diagonal
5mm diagonal
•
Tools for loading and centering for:
Tools for loading and centering for:
4 inch (100 mm) substrate
4 inch (100 mm) substrate
2 inch (50 mm) substrate
2 inch (50 mm) substrate
Solitic is the main manufacturer of this equipment, Various models from the
Solitic is the main
manufacturer of this equipment, Various models from the
same Company shown below
same Company shown below
$30,000
$30,000
75
75
S A M I U R R E H M A N ( s a m i r e h m a n . b l o g s p o t . c o m )Photolithography
BAKE OVENS
BAKE OVENS
Yes 450pb oven
Yes 450pb oven
Description:
Description:
The 450PB is a high temperature vacuum oven using a programmable temperature
The 450PB is a high temperature vacuum oven using a programmable temperature
controller and programmed vacuum and nitrogen flow cycles for curing of polyimide films.
controller and programmed vacuum and nitrogen flow cycles for curing of polyimide films.
The unit features filtered heated nitrogen purging from the entire surface of the roof
The unit features filtered heated nitrogen purging from the entire surface of the roof
through the floor of the chamber. This flow acts to clean the wafers during the process.
through the floor of the chamber. This flow acts to clean the wafers during the process.
Specs
Specs
Capacity: Up to two boats of 6
Capacity: Up to two boats of 6
inch wafers
inch wafers
Ramp: 8°C/min
Ramp: 8°C/min
Cool-down: 1-2°C/min
Cool-down: 1-2°C/min
Max Temperature: 400°C
Max Temperature: 400°C
Idle Temperature: 50°C
Idle Temperature: 50°C
$22,500
$22,500
76
76
S A M I U R R E H M A N ( s a m i r e h m a n . b l o g s p o t . c o m )WAFER PROCESSING
WAFER PROCESSING
Deposition
Deposition
Etching
Etching
Ion
Ion
implantation
implantation
•
CVD
CVD
•
PECVD
PECVD
•
PVD
PVD
•
SPUTTERING
SPUTTERING
•
EVAPORATION
EVAPORATION
•
MBE
MBE
•
DRY ETCHING
DRY ETCHING
•
WET ETCHING
WET ETCHING
•
DIFFUSION
DIFFUSION
•
ANNEALING
ANNEALING
77
77
S A M I U R R E H M A N ( s a m i r e h m a n . b l o g s p o t . c o m )CHEMIC
CHEMICAL V
AL VAPOR DES
APOR DESPOSITION
POSITION
Chemical Vapor Deposition is the formation of a
non-volatile solid film on a
substrate
by the reaction
of vapor phase chemicals (reactants) that contain the
required constituents.
78
78
S A M I U R R E H M A N ( s a m i r e h m a n . b l o g s p o t . c o m )CHEMIC
CHEMICAL V
AL VAPOR DES
APOR DESPOSITION
POSITION
•
Gases to be reacted are entered into the CVD
Gases to be reacted are entered into the CVD
chamber and react to produce the
chamber and react to produce the desired
desired
material to be deposited on the wafer under
material to be deposited on the wafer under
extremely high temperature.
extremely high temperature.
•
W
Wafer temp is cooler than the
afer temp is cooler than the furnace
furnace
•
Changing the reacting gases we can produce
Changing the reacting gases we can produce any
any
material to be
material to be deposited
deposited
79
79
S A M I U R R E H M A N ( s a m i r e h m a n . b l o g s p o t . c o m )PECVD
PECVD
•
PECVD uses two electrodes one of which
PECVD uses two electrodes one of which
contains the wafer
contains the wafer
•
A strong electric field b/w the e
A strong electric field b/w the electrodes ignites
lectrodes ignites
the plasma which
the plasma which decomposes the reactant
decomposes the reactant
gases into the material to be deposited on
gases into the material to be deposited on the
the
wafer substrate.
wafer substrate.
80
80
S A M I U R R E H M A N ( s a m i r e h m a n . b l o g s p o t . c o m )SPUTTERING
SPUTTERING
•
High energy plasma
High energy plasma knocks metal atoms out of
knocks metal atoms out of
its crystalline struct
its crystalline structure and are deposited on
ure and are deposited on the
the
wafer substrate!
wafer substrate!
•
Mainly used for
Mainly used for
creating metal
creating metal
cont
contacts
acts (Aluminum,
(Aluminum,
Titanium etc)
Titanium etc)
81
81
S A M I U R R E H M A N ( s a m i r e h m a n . b l o g s p o t . c o m )SPUTTERING
SPUTTERING
PVD75 RF Sputterer
PVD75 RF Sputterer
Description
Description
•
The RF sputterer can be used to deposit many dielectrics.
The RF sputterer can be used to deposit many dielectrics.
•
Sputter two or more dissimilar materials simultaneously
Sputter two or more dissimilar materials simultaneously
•
for complete control of film
for complete control of film stoichiometry (co-deposition)
stoichiometry (co-deposition)
•
Integrated touch screen control
Integrated touch screen control
•
Single substrate up to 12" diameter
Single substrate up to 12" diameter
•
Multiple substrate up to 4"
Multiple substrate up to 4" diameter
diameter
•
Substrate fixture rotation up to 20rpm
Substrate fixture rotation up to 20rpm
$60,000
$60,000
82
82
S A M I U R R E H M A N ( s a m i r e h m a n . b l o g s p o t . c o m )SPUTTERING
SPUTTERING
A
AR
RC
C--1
12
2M
M ssp
put
uttte
er
riing
ng ssy
ysstte
em
m
Gases available: Ar, O2 & N2
Gases available: Ar, O2 & N2
- DC sputtering power source: 2 x
- DC sputtering power source: 2 x
250W
250W
- RF sputtering power source: 600W
- RF sputtering power source: 600W at
at
13.56MHz
13.56MHz
- Chamber pressure: 5x10
- Chamber pressure: 5x10
-6
-6
torr
torr
--
Substrate si
Substrate size: 2”
ze: 2”, 4”
, 4”
wafer or square
wafer or square
glass, or specimen
glass, or specimen
- Targets available: Ag, Al, Al/Si (1%), Au,
- Targets available: Ag, Al, Al/Si (1%), Au,
Cu, Cr, Hf, Mo, Pt, SnO2, SiN, Ti, TiW
Cu, Cr, Hf, Mo, Pt, SnO2, SiN, Ti, TiW
http://www.mff.ust.hk/Eq_Sputter.htm
http://www.mff.ust.hk/Eq_Sputter.htm
$55,000
$55,000
83
83
S A M I U R R E H M A N ( s a m i r e h m a n . b l o g s p o t . c o m )SPUTTERING
SPUTTERING
CVC DC Sputterer
Description
Description
The DC sputterer is used to coat samples with metals. Metal coatings
The DC sputterer is used to coat samples with metals. Metal coatings
are usually performed with this sputterer or with the CVC E-Beam
are usually performed with this sputterer or with the CVC E-Beam
evaporator. -Process wafers/substrates up to 6" -Computer-controlled
evaporator. -Process wafers/substrates up to 6" -Computer-controlled
planetary system for uniform deposition -Two 3" and two 8" sputter
planetary system for uniform deposition -Two 3" and two 8" sputter
guns
guns
Capabilities
Capabilities
Deposition - Metal Deposition - Aluminum
Deposition - Metal Deposition - Aluminum
Chromium
Chromium
- Copper
- Copper
Gold
Gold
Iron
Iron
Nickel
Nickel
Palladium
Palladium
Platinum
Platinum
Ruthenium
Ruthenium
$55,000 to
$55,000 to
110,000
110,000
84
84
S A M I U R R E H M A N ( s a m i r e h m a n . b l o g s p o t . c o m )EVAPORATION
EVAPORATION
•
Metal atom to be deposited are held in a
Metal atom to be deposited are held in a
tungst
tungsten coil
en coil which carries huge
which carries huge currents
currents
•
