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BIPOLAR
TECHNOLOGY
The Bipolar Integrated Circuits Principles and Manufacturing
version 2.2 En
VPS
This presentation was prepared for the needs of the company ON Semiconductor with the aim
to approximate the production principle of bipolar integrated circuits especially to those who
have never met this topic.
The author, VPS s.r.o. thanks to TESLA SEZAM, a.s., TEROSIL, a.s. and SCG Czech Design
Center s.r.o. based in Roznov pod Radhostem, Czech Republic for their friendly help in
compiling the presentation and for the chance to shoot the video clips in the production rooms.
In our effort to continuously improve our products we thank you in advance for your comments,
which will help us in the production of further versions..
Piestany, June 2001
VPS s.r.o., P.O. Box B-11, Partizanska 31, 921 01 Piestany 1, Slovak Republic
tel., fax.: +421 838 7730151, email: [email protected]
Bipolar Technology 2.2 En
2
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Clicking the left mouse on the running video
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function, it means one step backward. Press
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transition to the slide Contents
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transition to a slide with relevant information
next slide
Bipolar Technology 2.2 En
end of presentation
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3
Contents
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Introduction
Voltage Regulator
Where Else it can be Used?
What is Inside an Integrated Circuit?
Semiconductor
Silicon - the Structure
Silicon - Inside the Single Crystal
Silicon - Conductivity Type
Silicon - PN Junction - Bipolar Technology
Diode Function
Transistor Function (NPN)
Silicon Wafer
Why is it “integrated”?
Surface of a Chip
Is the Whole Thickness of a Chip Utilized?
What is Under the Surface?
Cross Section
How it Originates?
Buried Layer
Collector
Second Part of Insulation and the Base
Emitter
Contacts and Metallization
Passivation
Final Wafer Treatment
Testing
Assembly
Bipolar Technology 2.2 En
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the Controlling the Presentation slide
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Thermal Oxidation
Oxidation (diffusion) Furnace
Oxidation Furnace - Gas System
Diffusion
Diffusion Furnace - Gas System
Photolithography and Etching
Plasma Etching
Ion Implantation
Ion Implanter
Epitaxy
Epitaxial Reactor
Sputtering
Contamination
Silicon Fragment
Clean Rooms
Semiconductor Hygiene and Wafer Handling
Process Control
Materials for the Semiconductor Technology
Reverse Osmosis
Diffusion - the Principle
Gas Flow Measurement
Anisotropic and Isotropic Etching
Names of the Layers
Some Physical Units
4
Introduction
The Roznov pod Radhostem, Czech Republic
manufacturing location is a significant
European source of semiconductor devices.
Voltage regulators, operational amplifiers and
various control circuits are designed and
manufactured there in the high tech clean
rooms.
The voltage regulator MC 7812 in TO220 case
is a typical product from Roznov.
It was used as an example
of bipolar analog integrated circuits.
Bipolar Technology 2.2 En
5
Voltage Regulator
There
The
To
have
course
is aa stable
well-known
of an supply
unstable
variant
(insupply
order
of the
the
voltage
stabilized
light is
bulb
represented
does
voltage
notsupply
blink),
onon
the
a voltage
the
diagram
left bottom
stabilizer,
- the picture.
light
e.g.
bulb
theis
blinking. The
integrated
circuit
mostMC
of 7812,
electrical
hasappliances
to be used.could
not work reliably powered like this.
16
14
Voltage [V]
12
10
8
6
4
2
0
Time
MC 7812
Bipolar Technology 2.2 En
6
Where Else it can be Used?
The voltage
Wherever
This
is the amotherboard
stable
regulators
supply
are
with
isnot
necessary.
a only
microprocessor.
in the
Oncentral
the
picture
The
power
microprocessor,
supply
we canbut,
seeaccording
a just
personal
as many
tocomputer
theother
requirements,
parts,
wellknown
needs
also
at ato
different
stable
everybody.
supply
places
There
voltage
of particular
arefor
several
itsboards.
functioning.
boards
with many parts inside the computer.
Bipolar Technology 2.2 En
7
What is Inside an Integrated Circuit?
The
If
This
webasic
small
remove
material
piece
the of
black
of
matter
a material
chip
is is
called
a from
chip.
the
semiconductor
- silicon.
package,
After
an enlargement
we can
see we
the can
leads
see
leading
its
up
to a small piece of matter inside which the
structure.
whole function of a regulator proceeds.
Bipolar Technology 2.2 En
8
Semiconductor
Electrically Nonconductive Materials
- insulators glass
china
plastics
.
.
.
Conductivity
From
Nonconductive
Conductive
Finally
the
there
view
materials
of
are
of
the
materials
semiconductors,
electric
semiconductors
- conductors
conductivity
- insulators
having
- can
especially
-the
e.g.
be
their
materials
glass,
can beplastic,
china,
metals,
electrical
influenced
divided
but
conductivity
by
also
temperature,
wood,
asgraphite
follows:
etc.
between
Their
and
electric
some
"nonconductivity"
that field
of
others.
anand
insulator
Their can
be influenced
conductivity
and
especially
conductor.
bycan
avery
tiny
This
beslightly
amount
partially
can beonly.
substantially
of
influenced,
foreign materials.
mainly
influenced
by
These
admixtures
calledgermanium
dopants, could
temperature.
in
a wide
range. Silicon,
and be
galliumarsenide
chemical
elements
arelike
theboron,
well-known
phosphorus,
semiconductors,
arsenic
silicon
or
antimony...
is the most commonly used one.
Electrically Conductive Materials
- conductors silver
copper
gold
.
aluminum
iron
.
graphite
Semiconductors
Influenced by temperature, electric field or by an impurity
of foreign material the semiconductor can behave once as
an insulator yet as a conductor.
Bipolar Technology 2.2 En
silicon
germanium
galliumarsenide
9
Silicon - the Structure
It is
The
If
Each
wenecessary
basic
basis
move
silicon
material
of
aatom
acopy
silicon
to add
has
of this
a
crystallographic
that
four
voltage
structure
silicon
neighbors,
regulator
has
by 1/4
structure
which
chip
of the
itis
silicon.
is
internal
forms
appropriate
a face
aSilicon
diagonal,
bond
centered
properties
with.
is aboth
cubic
chemical
for
the
structure
semiconductor
original
element
-and
a from
cube
thechips
the
with
groupwhen
atoms
shifted
only
IV
in
atoms
its
inthe
the
vertices
form
atoms
Periodic
aand
diamond
in the
table.
in the
whole
type
wallvolume
of
centers.
the of the
structure,
chip
are arranged
which is exactly
the silicon
according
structure
to as
thiswell.
structure. Such and arrangement is called
single crystal. A view of a fictitious observer
inside the silicon single crystal looks like the
following picture.
28,0885
Si
14
2,33 g/cm3
Silicon
Bipolar Technology 2.2 En
10
Silicon - Inside the Single Crystal
Bipolar Technology 2.2 En
11
Silicon - Conductivity Type
Ontechnology,
An
Physically,
Only
Such
In
admixture
the
aa very
pictures,
slight
the
tiny
amount
of
we
boron
amount
some
the
usually
P-type
admixture
ischemical
difficult
ofknow
asilicon
dopant
a
to
causes
elements
low
formulate
will
isdoped
be
sufficient
a represented
different
- dopants,
in
silicon
grams,
formechanism
-doping
can
up
by
therefore
to,
a silicon.
shade
say,of1018
the
of
substantially
electric
For
unit
atoms
blue,
example,
ofthe
acurrent
of
dopant
N-type
dopant/cm3
influence
1 transfer
gram
concentration
silicon
of
and
the
by
in
phosphorus
silicon
asilicon
a heavy
shade
used
than
electric
doped
ofin
(on
red.
phosphorus
thethe
conductivity.
silicon
semiconductor
Deeper
pan -ofwith
shades
or
scales)
arsenic.
Boron,
higher
technology
will
is Silicon
phosphorus
doped
sufficient
is
concentration
represent
the number
with
to
a boron
change
higher
and
of a
arsenic
dopant
isdopant.
concentration
1000
called
atoms
are
tons
the
This
especially
P-type
of
per
heavy
silicon
ofunit
a dopant.
silicon
doped
used
volume,
(a fullwhile
for
silicon
train)
usually
this
silicon
into
is
purpose.
called
given
the
doped
N-type
P+
in with
or
3 or
phosphorus
one.
#atoms/cm
N+
type silicon.
of silicon.
arsenic The
is called
concentration
the N-typeofone.
1g phosphorus per 1000
tones of silicon is 45000000000000 atoms/cm3 of silicon.
1 gram of phosphorus in 1000 tons of silicon
=
45 000 000 000 000
phosphorus atoms
in
1 cubic centimeter of silicon
conductivity
conductivity
P
N
(4,5 . 1013 cm-3)
10,81
heavy doped silicon
tens - hundreds kg / 1000 tons
5B
(1018 to 1021 cm-3)
Boron
P+ , N+
Bipolar Technology 2.2 En
(Positive)
(Negative)
30,97376
15
P
74,9216
Phosphorus
33
As
Arsenic
12
Silicon - PN Junction - Bipolar Technology
A two-layer
The
interface
diode
between
and three-layer
P-type andtransistor
N-type layers
are the
of silicon,
bestcalled
PN devices.
junction,
an exceptional
knownthe
bipolar
Thehas
bipolar
transistors physical
are classified
behavior.
as
either NPN
Semiconductor
or PNP according
devicestowhich
the arrangement
function is based
of the
on PN junction
interfacing
semiconductor
are bipolar layers.
devices and their manufacturing
technology is called bipolar technology.
P
PN Junction
Transistor PNP
N
P
N
P
N
P
Diode
Transistor NPN
Anode
Collector
Base
N
P
N
Cathode
Emitter
Bipolar Technology 2.2 En
13
Diode Function
Now, we
Diode
is aconnect
simple the
PN cathode
junction. to
Onthe
thebattery
picture,
negative
the
diodeand
pole
is connected
the anode to
through
a circuit
thewith
bulb
a light
to thebulb
positive
and
battery.
one.
TheWhen
diodethe
conducts
P layerelectric
- anodecurrent
- is connected
and the bulb
through The
shines.
the light
diodebulb
conducts
to the battery
electric negative
current only
pole,
if the
there is negative
battery
no electric
pole
current
is connected
flowing through
to the N-layer,
the circuit.
The bulb does not shine.
cathode.
IA = 2
0A
Anode
P
Cathode
N
+
Keyboard
P
Bipolar Technology 2.2 En
N
14
Transistor Function (NPN)
Transistor,
On
There
Now,
Let´s
the
we
move
ispicture,
are
still
connect
different
inano
his
sleeve
the
current
principle,
a kinds
transistor
small
on flowing
the
of
watch
isdiodes
resistor
created
is into
connected
battery
and
the
now.
bybase.
transistors.
to
three
The
the
to aIn
base
layers.
circuit
the
There
with
collector
circuit.
resistance
From
athe
battery
isThere
acircuit,
big
thin
is reduced
ones
is
and
(1-3
athere
small,
aused
mm)
bulb.
and
islayer
say,
to
no
The
the
control
current
10
of
base
bulb
mA
a P-type
engines
is
current
as
current
connected
well.
base
to
doubles.
flowing
The
thebulb
to a
between
collector
does
into
A
ones
response
the
notbase.
we
can
-two
shine.
it in
isfind
N-type
Physical
the
inIfcollector
on
we
collector
layers.
the
compare
processes
voltage
circuit.
circuit
Thethe
N-type
regulator
Amakes
in
transistor
resistor
semiconductor
layers
the
chip.
isto
bulb
are
a
called fully.
connected
water
layers
shine
tap,
the
cause
emitter
this
to
Similar
athe
situation
much
base.
and
to an
bigger
the
represents
open
collector,
current
valve.athe
flow
By
closed
P-type
aalso
transistor
valve.
inlayer
the
is called
collector
we
can regulate
the
circuit.
base.
In
bigThe
comparison
changes
arrangement
oftocollector
theinwater
this
current
way
main,
isby
the
the
NPN transistor.
valve
means
isof
half-opened.
small changes of the base current.
Transistor works as an amplifier.
ICK = 2
0A
1
R = 40
80 W
IB = 20
0 mA
10
mA
N
P
N
+
Base thickness 1-3 µm
Keyboard
P
Bipolar Technology 2.2 En
N
15
Silicon Wafer
Secondary Flat
VIDEO 320 x 240
P <100>
<100>
Primary Flat
diameter: 100 mm, thickness: 525 µm
<111>
On integrated
An
For
The
the
that
silicon
crystallographic
conductivity
wafers
video,
reason,
wafer
arecircuit
there
fabricated
many
(P
is or
round-shaped.
are
chip
orientation,
N)
chips
some
is
type
byvery
are
cutting
scenes
and
small,
processed
in aThe
respect
from
silicon
from
just
diameters
athe
to
awafer
few
the
square
together
of
crystallographic
monocrystalline
silicon
100,wafers
wafer
millimeters.
125,
in one
150
surface,
manufacturing
slice
orientation
silicon
mm
Itof
or
would
iscylinder
semiconductor
important
more
are
be
line.
are
difficult,
encoded
pulled
commonly
for the
from
-ifsilicon
in
final
not
amolten
used.
even
impossible,
wafer.
A
electrical
relative
silicon
100 mm
At
inposition
special
the
properties.
wafer
toend
produce
of
equipment.
is
ofprimary
about
the
In each
practice,
process
half
and
The
chip
ofsecondary
millimeter
the
melting
individually.
wafer
orientations
point
is
flat
thick.
cut
on
ofup
into individual
Already
according
each
silicon
wafer.
isthe
1415
towafer
The
the
chips.
°Ctop
pictures
(in
material
side
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of
are
issilicon
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then.
as <111>
withor660
<100>.
°C).
Bipolar Technology 2.2 En
16
Why is it “integrated”?
All the
The
voltage
components
regulator
of is
a an
regulator
electronic
are circuit
the blueprint
matched
- integrated
of which-we
intocan
onesee
chip.
in the
This is
background.
why
the final On
device
the is
chip,
called
we can identify
integrated
circuit.
particular terminals
as well as various
devices - transistor, resistor, capacitor ...
Bipolar Technology 2.2 En
17
In our conception
Details
According
of atochip
the structure
blueprint,
the transistor
cannot
we can
consists
be
identify
seenofwith
a3
the naked
collector,
silicon
layers
an
eye.
emitter
and
Wewe
need
and
canaahardly
base
microscope
on
findthe
such
witha at
least tenfold
microphotograph.
structure
on the
magnification.
picture.
The Q8
Therefore
transistors
When looking
it iscovers
at
the area
necessary
chip surface,
of to
145
analyze
x only
80 µm.
the
some
under
complex
surface
of lanes
space.
can be seen. The whole secret of the circuit
function is deeper in its structure. According to
the blueprint, there should be many various
components there, especially transistors. Let´s
choose the, say, Q8 transistor and let´s
investigate its structure.
Collector
Emitter
Base
Collector
N
P
N
Emitter
Base
80 µm
Surface of a Chip
Q8
145 µm
Where this structure is?
Bipolar Technology 2.2 En
18
Is the Whole Thickness of a Chip Utilized?
vertical : horizontal 1 : 1
20 µm
80 µm
340 µm
vertical : horizontal 5 : 1
Because
The
Q8 transistor
layer
of
with
thisalldimensional
the
covers
integrated
an area
disproportion
circuit
of 145 x 80
in
µm. The thickness
components
horizontal
(145
reaches
x 80ofµm)
finalized
justand
20 µm
vertical
chip
under
is (5
340
the
toµm.
20
(Let´s
surface.
µm)
directions
remind
Moreover,
that
the the
structure
many
silicon
details
cross
wafer
are
sections
thickness
in the
is 525
upper
are
represented
5µm.
µmThe
only.wafer
in theisway
finished
of thebyquintuple
grinding
at the of
scale
end
theofvertical
a manufacturing
dimensionprocess.)
in comparison
to the horizontal one.
145 µm
Bipolar Technology 2.2 En
19
What is Under the Surface?
In order
Now,
To
The
On
this
improve
the
this
integrated
transistor
buried
NPN
P-type
last
we
layer
PN
surface,
picture,
to
layer
can
transistor
image
interface,
layer
the
region
there
see
of
structure
circuit
collector
the
there
the
prevents
inward
the
are
isstructure
consists
transistor
close
there
structure
consists
P+
are
ischaracteristics,
the
type
metal
built
the
under
is of
cell
is
atransistor
walls
is
of
in
relatively
3imaged
connections
the
with
many
layers:
the
a better
dividing
emitter.
surface
N-type
the
at
from
the
N-type
thick
whole
way,
thechip
the
in
a
components.
silicon
chip
we
transistor
N+
mutual
collector,
surface
forming
order
same
will
type
into
to
scale
layer
use
influencing
is
the
enable
region
the
P-type
structure.
connected
atransistor
both
(the
cells
bigger
Informing
the
order
base
red
infor
by
horizontal
transistor
We
enlargement
layer)
particular
to
"leakage"
base.
not
and
the
the
can
toN-type
on
cell
buried
see
be
to
and
the
components
bottom.
the
of
"communicate"
the
and
emitter.
P-type
vertical
electric
layer
components
insulation
we
Since
by
silicon
will
Here,
an
ofitNundesirably
substrate
integrated
make
reaching
is
current
the
type
with
directions
incollector
depth,
other
column.
the
under
down
silicon
(the
and
components
circuit.
itinfluenced
isisthe
blue
itformed
to
called
represents
layers
These
the
insulation.
layer).
P-type
the
by
one
on
transparent.
walls
the
buried
the
another,
the
silicon
N-type
chip.
are
real
layer.
called
substrate.
proportion
there
siliconmustof
be some
insulation.
limited
Q8
transistor.
byindependent
the insulation
areas
fromon
sides
the and
chip,bya the
kind
of cells.layer
buried
Let´sfrom
have
bottom.
a look at the cell of "our" Q8
transistor.
Emitter
Base
Collector
N
P
N
N-type
layer
Collector
N
P-type pad
Emitter
P
Base
Bipolar Technology 2.2 En
20
Cross Section
passivation
field oxide
Actually
Technological
We
The
have
shades
right
transistor
silicon
already
structure
ofprocesses
structure
blue
is named
not
isrepresent
atransparent,
bit
described
some
do
different
not
the
layers.
make
P-type
therefore
so
from
far
itHere
possible
the
is
silicon
created
itleft
are
is
possible
to
the
while
picture
in
aproduce
names
very
the
ofto
complicated
N-type
the
of
squared
study
Q8
thesilicon
transistor
the
next
shapes
vertical
way,
ones.
is red.
in
profile.
like
structure
dozens
Inon
reality,
The
theofjust
right
Q8
thein
isactual
cross
sections.can
picture.
profiles
relatively
technological
Functionally
small
Letbe
us
steps.
visualized
and
remind
itThe
the
is difficult,
that
squared
following
too,
the
although
vertical
if“sharp”
not
animation
impossible,
not
scale
shapes
sois
fivehitnot
are
colorfully.
to
represents
times
it by
suitable
On
bigger
the
thethe
grinding
chain
as
than
right,
well.
ofthe
of
there
production
On
cross
horizontal
the
is asection.
left steps.
picture,
one.Thethere
right
is a more
microphotography
picture
comes
realistic
fromface
ofthe
a of
real
biggest
the
structure
actual
transistor
profile.
profile
on the
visualized by selective etching.
chip.
emitter
base
collector
metallization
epitaxial layer
Emitter
Base
Collector
N
P
N
insulation
substrate
buried layer
buried layer interconnection
Bipolar Technology 2.2 En
21
How it Originates?
Thus how it originated?
Here in few seconds. Actually it takes hundreds of
hours and the real structure is even more complicated.
The next slides provide a detailed walk-over trough a
semiconductor chip manufacturing process.
Keyboard
P
Bipolar Technology 2.2 En
N
22
Buried Layer
epitaxial layer
The basic material is the P-type silicon wafer with the
<100> orientation. On this substrate, the buried layer,
the first part of an insulation and an epitaxial layer will
be build up.
Epitaxy
Thermal Oxidation
Names of the Layers
Photolitography and Etching
Ion Implantation
first part of insulation
Diffusion
buried layer
Epitaxy
Oxide Etching
Boron Annealing
Ion Implantation (boron)
Photo and Etching (insulation)
Arsenic Annealing
Ion Implantation (arsenic)
Photo and Etching (buried layer)
Oxidation
Bipolar Technology 2.2 En
23
Collector
Now, an interconnection of the buried layer and chip
surface will be created. This is also the place for future
contact to the collector.
Names of the Layers
Thermal Oxidation
Photolitography and Etching
Diffusion
buried layer interconnection and collector contact
Oxidation and Phosphorus Annealing
Oxide Etching
Diffusion (phosphorus)
Photo and Etching (collector)
Oxidation
Bipolar Technology 2.2 En
24
Second Part of Insulation and the Base
At this stage, the second part of insulation and the
base layer will be created. Notice that the second part
of insulation goes downward to the first part until join it.
Names of the Layers
Photolitography and Etching
Diffusion
Ion Implantation
second part of insulation
base
Thermal Oxidation
Oxidation
Boron Annealing
Ion Implantation (boron)
Photo and Etching (base)
Boron Annealing
Vacuum Diffusion (boron)
Photo and Etching (insulation)
Bipolar Technology 2.2 En
25
Emitter
The emitter layer will be created now. This operation is
concurrently used for collector contact characteristics
improvement.
emitter
Cross section
Photolitography and Etching
Names of the Layers
Diffusion
Thermal Oxidation
diffusion for contact improvement
Diffusion (phosphorus) and Oxidation
Photo and Etching (emitter)
Bipolar Technology 2.2 En
26
Contacts and Metallization
The contacts to the particular chip components are
created at this step. The components will be
interconnected by metal strips - metallization. This is
made of alluminium with the admixture of small amount
of copper and silicon.
Names of the Layers
Photolitography and Etching
Sputtering
metallization
Photo and Etching (metallization)
AlCuSi Sputtering
Photo and Etching (contacts 2)
LPCVD Oxide
Photo and Etching (contacts 1)
Bipolar Technology 2.2 En
27
Passivation
Finally, the last layer on the chip is created passivation. It is made of silicon nitride at the
temperature of 400 °C and protects the chip from
external contamination. In this layer, contact windows
for the leads will be created consecutively.
Photolitography and Etching
Names of the Layers
passivation
Photo and Etching (passivation)
Plasma Nitride Deposition
Bipolar Technology 2.2 En
28
Final Wafer Treatment
Silicon Wafer
Chip
20 mm (structure)
525mm
340 mm
VIDEO 320 x 240
During
The
silicon
the manufacturing,
wafer thicknessvarious
is 525 micrometers.
undesirable It is
necessary
layers
occur
because
on the back
of a mechanical
surface. These
strength
layers
during
will
theremoved
be
manufacturing
by wafer
- simply
back side
in order
grinding
not toand
break
thethe
wafers.
final
thickness
This thickness
will be adapted
is unnecessary
to 340 micrometers.
and even
inappropriate
On
the video, for
we the
canfinalized
see a working
chip. cycle of a
grinding machine.
Bipolar Technology 2.2 En
29
Testing
Onthe
After
If
the
the
probe
enclosed
technological
structure
videoelectric
process
clip, there
parameters
is are
finished,
some
fulfill
electrical
shots
the
parameters
requirements,
from
a test site.
of the functionality
characteristicofcomponents
each chip onare
wafer
measured
is
tested. Aon
test
probe
equipment
structures
- tester
made
is connected
for this reason
to the
on each
chip
by means
silicon of
wafer.
metalThe
pins
probe
and tests
structures
its electrical
are
measured onAseveral
parameters.
rejectedchosen
chip iswafers
colored.
from each
manufacturing lot.
VIDEO 320 x 240
REJECT
OK
Probe structures
Bipolar Technology 2.2 En
30
Assembly
On the
The
Afterwards,
silicon
functional
video
wafer
the
clip,
chips
copper
with
there
are
chips
base
are
soldered
some
iswith
sawn
bonded
or
shots
up
glued
with
from
chip
on
aan
aand
diamond
copper
wires
assembly
isbase
molded
saw
line.
with
into
into
leads.
individual
a molding
Thechips.
leads
compound
are connected
similarly
with
to
thethe
picture.
chip contacts
After theby
final
a thin
treatment
copper,and
goldtests,
or
alluminium
the
integrated
wirecircuit
(0,1 mm).
is completed.
VIDEO 320 x 240
Bipolar Technology 2.2 En
31
1000
During
Silicon
For
If
But
On
The
Now,
the
the
the
chips,
source
oxidation
at
there
silicon
dioxide,
oxidation,
right
native
higher
itis
for
is
diagram,
wafer
the
speed
is
oxide
prepared
temperature
oxide
or
also
profile
oxide
more
surface
protects
depends
accelerated
creation
there
grows
familiarly
in
created
the
isis
the
absolutely
the
is
the
quickly
on
form
oxidation
silicon
by
access
the
by
oxide,
dependence
aofthe
temperature
photolitographic
in
afrom
clean,
thin
the
is
presence
ofcontinues.
aother
place
the
layer
very
the
ofwafer
the
by
and
of
important
growing
reaction
molecules
With
on
the
oxide
dopant
process
where
one
kind
growing
film
silicon
hand
(boron
directly
of
onmaterial
thickness
of
oxidizing
silicon
the
and
oxygen
is
the
or
right
exposed
on
phosphorus)
thickness
ambient
atoms
for
the
on
material.
bottom
tothe
wafer
oxidation
the
with
and
semiconductor
oxygen
of
silicon
picture.
surface
itoxygen
The
oxide
intakes
silicon.
time.
on
higher
atoms
film,
What
away
the
or
by
Notice
airborne
It
thermal
itother
technology.
temperature
and
profile
is
isitsstill
the
44%
hand.
willof
It is
oxidation.
water
oxidation
more
During
is
differences
represented
occur
silicon.
the
not
difficult
faster
after
vapor
the
In
only
at
the
The
oxidation
the
between
room
the
occurs
at
afor
place
great
SiO
oxidation
the
oxidation.
oxygen
temperature
already
where
layer
material
the bottom
amount
temperatures
or
ofgrows
The
oxide
water
this
at(in
astops.
oxidation
structure?
picture,
room
the
at
already
ofvapor
asilicon
form
high
At
temperature.
1000
notice
to
ain
exists,
of
temperature
higher
decreases
get
water
quartz)
°Cto
the
and
the
theA
2right
for fusing
by
very
temperature
silicon
then.
vapor
1100
final
oxidation
various
profile
thin
°C
Resulting,
isinterface
3-4
and
oxide
is
the
tools
after
slower
times
(800-1200
between
Ofilm
the
and
atoms
oxidation.
faster
and
(1-2
oxide
the
equipment
the
the
with
°C),
nm)
process
than
dry
film
amount
silicon
however,
grows
oxidation
in
is construction
dry
divided
of or
-of
oxidation
oxygen
so
by
silicon
the
and
called
in
reaction
oxygen
the
oxidation
because
parts,
isnative
wayof
2 and
butwater-saturated
water
oxide.
molecules
slowing
that
hydrogen
in
decreases
itapproximately
isvapor
also
down.
accelerates
are
more
with
irreplaceable
able
slowly.
silicon.
oxygen.
44%
to pass
the
Itofresults
oxygen
inits
through
athickness
chip.
into
transport
the
thealready
isprofile
under
to thethe
createdon
original
silicon
drawn
interface.
silicon
oxide
the following
film
surface
up toand
picture.
the 56%
silicon
above
interface
it. by
diffusion.
O
Si
O
water
oxygen
Si
O
300
O
Si
O
O
Si O O
O
Si OOO
Time [min]
600
O
O
Si O O
O
Si
Si
O
Si
Si
O
Si
Si
O
Si
Si
Si
Si
Si
Si
Si
Si
Si
Si
Si
Si
Si
Si
Si
Si
Si
Si
Si
Si
Si
Si
Bipolar Technology 2.2 En
500
1000°C
O
O
1100°C
1000°C
H
O
H
O
O
O
Thickness [nm]
Thermal Oxidation
SiO2
56%
original surface
44%
Si
Oxidation Furnace
Diffusion - the Principle
32
Oxidation (diffusion) Furnace
During
The
After
equipment
thermal
furnace
process
the
the
temperature
process
oxidation
oxidation
temperature
starts
forisoxidation
with
finished,
oris
as
diffusion
loading
stabilized,
well
(400
or
the
as
to
diffusion
the
the
wafers
diffusion
1200°C)
the
wafers
silicon
process
are
processes
require
is,
into
wafers
unloaded
after
the
starts.
asetup,
are
furnace.
is
high
an
out
The
placed
temperature,
oxidation
controlled
from
gas
They
into
system
theare
afurnace.
quartz
(diffusion)
therefore
automatically
or
inserted
develops
In
some
siliconslowly
processes
carbide
an
the
furnace.
appropriate
quartz
accurate
notcarrier
to
the
The
tube
deform
to
temperature
process
-ambient
is
±1°C
a placed
boat.
the
orproceeds
wafers
for
Several
better.
into
isthe
lowered
aby
heated
heating
boats
in
fast
a before
quartz
heating.
are
wafers
element.
putit.
orinside
on
In
silicon
To
the
most
reach
the
loader
carbide
cases,
tube.
arm.
the
tube.
appropriate
In
wafers
theOn
furnace,
are
the
loaded
temperature
backside
there
into
can
of
thestability
the
betube
up
tube,
to
atlengthways,
several
lower
there temperature
ishundreds
a thin
thegas
heating
silicon
and
inlet element
the
tube
wafers
process
connected
consists
at the to
a gas
of
same
temperature
three
time.
system.
zones.
ramps-up
The
Each
gases
zone
after
blowing
has
thean
insertion.
from
individual
the front
power
aresupply
exhausted
and control.
to a
The
sanitation device.
temperature
is controlled by thermocouples (thin blue wires).
gas inlet
gas exhaust
gas exhaust
gas exhaust
Bipolar Technology 2.2 En
Oxidation
Oxidation Furnace - Gas System
Diffusion
Diffusion Furnace - Gas System
33
Oxidation Furnace - Gas System
Oxidation
Oxidation Furnace
Gas Flow Measurement
O2
H2
H2O
O2
combustion chamber
flowmeters
control valves
N2
Bipolar Technology 2.2 En
H2
O2
flowmeters
valves
N2
O2
quartz tube
The gas
task system
of the gas
for system
the "wet"
oxidation
is oxidation
to make
in pure
an
is oxygen
equipped
or
appropriate
in
with
a mixture
a combustion
oxidative
of oxygen
chamber,
environment
and nitrogen
inside inside
which
is simple.
the
hydrogen
quartz
tube. Itin
There
burns
iscan
oxygen
justbe
oxygen
pure
at the
oxygen,
orend
oxygen
ofaamixture
and
nozzle.
an of
appropriate
Hydrogen
oxygen
and nitrogen
proportion
burns
with of
a nearly
or
nitrogen
water-saturated
invisible
flowingblue
through
oxygen.
flame.
flow
The
The gas
flow is measured
controllers
hydrogen
combustion
into theand
tube.
controlled
produces water
by mass
vapor
flowthat
controllers.
enters
together
On the
withscheme
the residual
thereoxygen
are rotameters
the quartz
for simplification.
tube.
34
Diffusion
On the
Phosphorus
Diffusion
The
phosphorus
operation
silicon
is aatoms
forms
process
wafer,
temperature,
the
atoms
structure
gothere
by
through
are
which
ismoved
the
represented
the
the
the
operation
oxide
diffusion
by
dopant
the
layer
on
diffusion
time
atoms
mechanism
with
theand
right
the
penetrate
"windows"
from
picture.
mechanism
chemical
environment
N-type
structure
under
ininplaces
silicon
islets
the
to
ofsilicon
where
the
(red)
even
environment
oxide
are
ifthe
wafer
there
formed
on
doped
surface
silicon
is
can
no
regions
ininfluence
diffusion
P-type
wafer
in selected
should
and
silicon
the
from
in
regions.
be.
places
(blue)
environment.
depth
The
of
innot
wafer
The
thecovered
regions
diffused
physical
Ifprepared
the structure
by
not
layer
effect
oxide
like
protected
and
-this
penetrate
on
diffusion
dopant
the
is by
placed
picture
oxide
-surface
into
is into
applied
the
is
(green).
kept
silicon.
here.
at
Let´soxide
environment
This
The
high
concentration.
temperature,
ishave
the on
way
a where
look
the
The
how
silicon
at
the
dopant
the
the
islets
phosphorus
regions
phosphorus
wafer
concentration
formed
surface
doped
by
atoms
diffusion
must
diffusion
with
decreases
(can
phosphorus
be(chemical
thick
(or
be ion
also
symbol
in
(N-type)
enough
implantation)
downward
compounds,
P)
(about
are
into
from
formed
will
the
500
e.g.
the
deepen
P-type
nm
P
surface
under
silicon
more)
are
the
- the
become
at
silicon
a
so
wafer.
concentration
high
that
surface.
larger.
temperature
phosphorus
This
profile
of
2Oor
5)and
about
atoms
process
is
an additional
1000
doisnot
also
°C.
penetrate
process
known as
it.
characteristics.
"drive in". The boron
diffusion proceeds in a similar way.
Diffusion Furnace
Diffusion - the Principle
P
P
P
P
P
P
P
P
P
P
P
P
P
P
P
P
P
P
P
P
PP
Dopant
P
P
P
P
P
P
Ion Implantation
P
P
P
P
P P P
P
P
P P
P P
P
P
1000°C
Bipolar Technology 2.2 En
35
Diffusion Furnace - Gas System
Onthe
The
In
Oxygen
Phosphine
During
the
task
case
diffusion
a
enclosed
oxidizes
vacuum
of PH
of
thediffusion
can
from
video,
the
diffusion,
also
silicon
planar
from
we
furnace
becan
awafer
asources,
apowder
phosphorus
liquid
see
gas
surface
the
source,
system
of
a dopant
sealing
doped
as
source.
nitrogen
is
well.
silicon
is
to
ofextricated
create
the
That
The
bubbles
is
vacuum
chemical
is
the
an
thesource
from
way
3 diffusion
environment
through
how
mechanisms
planar
of
diffusion
a dopant.
silicon
ceramics
the
ampoule.
oxide
liquid
The
saturated
inside
plates
powder
saturated
and
theitwith
saturated
quartz
sweeps
together
with
dopant
tube
phosphorus
liquid
with
with
atoms
areavapor
silicon
similar
dopant
or along
its
oxide
wafers
tooxide
compounds
the
into
occurs
is
ones
placed
the
sealed
on
with
quartz
inside
the
into
-3valves
the
tube.
wafer
POCl
between
a
quartz
quartz
surface.
. ampoule
silicon
the
tube.
picture
The
wafers.
The
exhausted
saturated
itgas
isThe
POCl
flowgas
to
oxide
is
the
controlled
system
is,
vacuum
in supplies
the
bylevel
end,
oxychloride)
regulator
of
the10quartz
source
Pa
for(100
tube
ofor
3On
3 (phosphorus
electronic
phosphorus
with
000
000
nitrogen
times
flow
diffusion.
atoms
orlower
control
nitrogen
forthan
Also
meters.
thewith
the
diffusion
oxygen
aatmospheric
small
flows
into
amount
silicon.
into
pressure).
the
of oxygen
quartz
The
tube
optionally.
whole
of the
diffusion furnace,
ampoule
is placedreacts
into the
with
quartz
POCltube
ofhigh
the diffusion
temperature
furnace
and
3 at a
phosphorus oxide occurs finally.
then.
Diffusion Furnace
Gas Flow Measurement
quartz tube
doped silicon powder
vacuum
silicon wafers
POCl3
seal
N2 + POCl3 vapor
Diffusion from
Planar Source
planar diffusion source
Vacuum Diffusion
flowmeters
VIDEO 320 x 240
control valves
N2
N2
Bipolar Technology 2.2 En
O2
PH
N23
O2
silicon wafers placed front side
toward the diffusion source
36
Photolithography and Etching
UV light source
(dischange lamp)
VIDEO 320 x 240
photolithographic
mask
projection system
rinser
developer
negative photoresist
oxide
Oxidation
Bipolar Technology 2.2 En
Anisotropic and Isotropic Etching
Subsequent
Photolithography
A
The
Immersing
projection
wafer is
developer
the
system
immersing
covered
whole
removes
andprojects
wafer
with
etching
the
the
awafer
into
light
non-illuminated
aispicture
an
the
sensitive
into
etchant
part
aof of
the
technology
matter
photolithographic
photoresist
causes
mixture
-the
of
photoresist.
sulfuric
making
etching
from the
mask
acid
possible
ofwafer
During
uncovered
and
on and
the
hydrogen
the
to wafer
form
the
covering
oxide
wafer
the
- itinisthe
isa
patterns
fast
pattern
rinsed
photoresist
peroxide
rotation
- of
this
on
will
the
windows
the
is
of
remove
future
the
the
silicon
process
wafer
structure
up
the
wafer
toguarantees
photoresist.
the
ofsurface.
development.
-silicon
the wafer
asurface
On the
is
left
uniform
exposed
-The
enclosed
wet
picture,
pattern
etching.
photoresist
to
video,
UV
there
ofThe
mask
light.
there
ispolymerized
the
thickness
details
The
are
silicon
illuminated
particular
is all
copied
wafer
photoresist
over
phases
with
regions
in
thethe
the
is
oxide
wafer
photoresist
etching-resistant.
of
photoresist
the
layer.
surface.
photolithographic
layer.
polymerizeprocess.
and they become
insoluble by a developer.
37
Plasma Etching
gas manifold
Plasma
In
The
plasma
inserting
described
etching
etching
ofbatch
is
of
theused
equipment,
nitride
boat
system
for
and
utilizes
the
proceeded
pumping
the
silicon
high
plasma
reactivity
nitride
out
several
isofobtained
films
theofsilicon
etching
fluorine
by
and
atoms
a
chamber
wafers
gas
inhigh-frequency
particular
that
at is
the
occurs
followed
same
cases
during
time.
by
discharge
for
several
For
the
photoresist
decay
thepreparatory
atplasma
the
of removal.
freon
pressure
etching,
steps
CF4Plasma
ofalike
about
etching
molecules
100
heating
single
Pa.
wafer
can
up
The
at
and
be
equipment
equipment
a very
adapted
final high
cleaning
is
consists
totemperature
also
be of
close
used.
the
of awafers.
toThe
quartz
or
anisotropic
atadvantage
an
The
vacuum
electric
nitride
of
etching,
discharge
chamber,
etching
single
wafer
itself
therefore
a- such
vacuum
system
proceeds
aitstate
is
pump
is used
the
inoffreon
more
and
gas
for a
very
plasma
isuniform
high
called
precise
frequency
with
plasma.
etching.
the
patterns
oxygen
power
etching.unit.During
supply
admixture.
A gas flow
the process,
control unit
thetakes
gas composition
care for
accurate
inside
thepressure
chamberand
is changing
a gas composition
which can in
bethe
observed
chamber.
as
a color change of the discharge from the orange
through the blue up to a steel blue.
Gas Flow Measurement
Single Wafer System
N2
O2
CF4
working chamber
Anisotropic and Isotropic Etching
100 Pa
gas exhaust
cover
high-frequency power supply
Bipolar Technology 2.2 En
loaded boat
vacuum pump
38
Ion Implantation
During
Ion
Phosphorus
In
Annealing
the
implantation
places
the of
annealing,
ions
the
where
is
implanted
accelerated
a the
process
the
oxide
diffusion
wafer
when
by
layer
the
atof
the
is
aelectric
the
thick
high
dopant
phosphorus
temperature
enough,
field
atoms
andthe
are
atoms
"shoot" under
directed
phosphorus
activates
proceeds
tothe
asthe
ions
well,
phosphorus
the
wafer
get
silicon
which
stuck
surface
results
wafer
atoms
in penetrate
it surface.
and
in- they
an
they
enlargement
can
into
Let´s
do participate
not
a have
certain
reach
of
a look
depth
the
the
in at
the phosphorus
under
silicon.
electrical
implanted
theconductivity.
silicon
regions.
implantation
surface
TheThe
result
(gray)
conductivity
into
is in
represented
the
theP-type
regions
also depends,
silicon
on
uncovered
the wafer.
structure
of by
oxide layer
course,
profile
on
onthe
the
(green).
right
amount
bottom
Theofdepth
phosphorus
picture.
of penetration
If a (dopant).
sufficient
depends
dose
This was
on
the speedcalled
amount,
implanted,
(energy)
the N-type
dose,
ofisislets
ions
an another
and
(red)
it is
occur
important
an important
insidecharacteristic.
the P-type
implantation
silicon
on places
characteristic.
not protected
Theby
ions
oxide
speed
layer.
is in order of
hundreds kilometers per second.
Ion Implanter
Dopant
Diffusion
P
P
P
P P
P
1000°C
P
P
P
Bipolar Technology 2.2 En
P P
P
P
P P
P
39
Ion Implanter
Onreach
Ion
Vapors
Under
Positively
The
For
To
the
implanter
example,
process
requested
ions
the
enclosed
ofpassing
aphosphorus
charged
influence
uniform
proceeds
is
inphosphorus
an
the
video,
the
ions
equipment
distribution
voltage
ofgap
chloride
ainget
there
hot
high
are
off
ions
of
filament
is
accelerated
vacuum.
used
100
the
over
(PCl
aare
line
source
kV
the
directed
)inside
are
of
the
the
whole
ion
brought
and
phosphorus
by
ion
the
to
electric
enter
silicon
theinto
3for
implantation.
a
source
the
separator
field
ions
wafer,
implanters.
source
magnetic
in
speed
the
an
ofof
ions
gap
accelerator.
beam
is
You
ions.
We
field
about
by
phosphorus
can
of
have
proper
ofions
500
see
anThere
used
ion
is,
kilometers
the
setting
by
chloride
separator.
loading
the
ismeans
the
of
process
the
voltage
per
molecules
ofofThe
magnetic
silicon
second.
aofdeflection
magnetic
of 50
wafers
fall
field.
tointo
phosphorus
atoms
field
200
system,
into
the
thousand
bends
ormagazine,
scanning
atomic
the
implantation
volts
path
clusters
all
abetween
of
over
part
ions
with
into
of
the
so
the
the
the
surface.
electric
that
vacuum
accelerator
silicon
lighter
charge
wafer
system
ions- to
ions.
are
and a
describe
more
electrodes.
control
diffracted
system.
theThe
principle
than
ion flow
the
of or
the
heavier
beam
implanter.
ones.
produced in this
way hits the silicon wafer surface.
VIDEO 320 x 240
accelerator
vacuum
Cl
PCl
heavy ions Cl
50 - 200
kilovolt
+
deflection
system
-
P
P
magnet
P
P
PCl
P
P
Cl
P
P
P
P
P
P
P
P
P
40 kilovolt
-
+
light ions
Cl
ClCl
ClPP Cl
ClCl
ions source
P
Cl
Cl P
Cl
phosphorus chloride molecule
silicon wafer
PCl Cl phosphorus and chlorine positive ions
phosphorus (P)
PCl3
Ion Implantation
Bipolar Technology 2.2 En
P
gap
phosphorus doped silicon is N-type
40
Epitaxy
Epitaxy
The
After
If
there
process
result
theare
issurface
the
ofany
proceeds
the
growth
phosphine
process
etching
ofatthe
is
high
is(PH
finished,
silicon
from
temperature
molecules
layer
few
thetoon
silicon
tens
about
the
present,
silicon
1200
3) a
wafer
°C.
chloride
the
micrometers
phosphorus
Hydrogen
surface.
(SiClthick
)The
vapors
atoms
epitaxial
layer
past
dope
are
has
theintroduced.
layer.
the
incandescent
the growing
same SiCl
epitaxial
silicon
4flows
4 reacts
crystallographic
wafers.
with
layer.
On
the
present
Boron
enclosed
When
compounds
hydrogen
hydrogen
properties
video,atthere
chloride
can
a as
high
be
are
thetemperature.
used
is
the
substrate,
added,
shots
for doping
itofbut
starts
The
theitascan
have aofloading
reacting
result
well.
wafers
different
with
this reaction
silicon
on
dopant
a and
susceptor
areconcentration
itfree
etches
silicon
andthe
their
atoms
wafer
or unloading.
even
surface
that
different
settle
dopant.
away.
on
You
the
can
Itsilicon
is
also
important
see
wafer
thesurface
tocontrol
remove
following
board
all the
of its
an
contaminants
crystal
epitaxial
lattice
or
surface defects of the silicon structure.
structure.
reactor.
H
H Cl
Cl H
H
Cl
Si
Cl
H
H
Cl
H
H Cl
H
P H
H
H Cl
H
H
Cl
Cl Si Cl
Cl
VIDEO 320 x 240
Si
Si
Si P
Si
Cl
Cl Si Cl
Cl
H
H
Si
H Cl
Epitaxial Reactor
Silicon - the Structure
Dopant
Bipolar Technology 2.2 En
41
Epitaxial Reactor
Epitaxy
Gas Flow Measurement
N2
H2
HCl
SiCl4
PH3
At this extremely
Epitaxial
During
the
reactor
process,
ishigh
an
the
equipment
temperature,
chamber for
with
the
the
the
process
growth
wafersofis
the epitaxial
flushed
proceeds
with
in the
nitrogen
layer.
way
Silicon
described
and hydrogen.
wafers
onare
theIn
loaded
slide
the Epitaxy.
on a
graphite
hydrogen
The
susceptor
block
environment
-with
susceptor.
wafers
the is
susceptor
The
cooled
susceptor
down
with is
wafers
then
placed
and
is
insidenitrogen
warmed
after
a quartz
up byflushing
the
glass
induction
bell-shaped
it is taken
heating
out
chamber.
at
from
thethe
Around
the chamber,ofthere
temperature
chamber.
about
is 1200°C.
an induction heating coil.
B2H6
gas exhaust
Bipolar Technology 2.2 En
42
Sputtering
It is possible
The
Fast
Against
following
argon
the atoms
target,
toanimation
sputter
bombarding
therealso
represents
is aother
holder
thematerials.
target
the
withprinciple
the
areThe
silicon
obtained
of
by
sputtering.
an
wafers.
composition
electric
Thedischarge
An
sputtered
ofargon
the sputtered
(Ar)
inalluminium
argon
atom
film
between
strikes
isfrom
theagainst
the
same
the target
target
as
anthe
settles
and an
alluminium
auxiliary
on
target
the composition.
wafers
electrode
plate
(and
surface
at
also
Inathe
low
on
insemiconductor
pressure
the
a high
other
speed
(0,1-1
parts(tens
industry,
of
Pa).
equipment)
km/sec)
The
the
target
and
films
itofforms
disperses
isalluminium,
connected
a sputtered
several
to
silver,
thealluminium
film
negative
gold,
of alluminium.
titanium,
terminal
atoms.
nickel
Magnetic
Ifofthe
aorhigh
alloys
field
alluminium
voltage
of
a magnet
alluminium
source
plate
placed
with
and
- the
copper
the
behind
target
auxiliary
and
the
- issilicon
target
strongly
electrode,
are
increases
bombarded
often
anode,
sputtered.
theto by
the
argon atoms,
positive
efficiency
one.
of the
The
theprocess
sputtered
ionizedand
argon
alluminium
it protects
atoms are
settle
thedirected
silicon
on thewafers
to the
surrounding
target.
from
the influence
subjects.
of the electric discharge.
VIDEO 320 x 240
Al
high voltage
supply
1000 V
Al
Al
Al
Al
Al
Al
Al
Al
Al
Al
Al
Ar
Al
Al
Al
Al
Al
Al
Al
Al
silicon
Al Al wafers
Al Al Al Al Al Al Al Al Al Al Al Al Al Al
Argon
Al
Al
Al
Al
Al
Al
Al
Al
Al
Al
Al
Al
Al
Al
Al
Al
Al
Al
Al
Al
Al
Al
Al
Al
Al
Al
Al
Al
Al
Al
Al
Al
Al
Al
Al
Al
Al
Al
Al
Al
Al plate - target
magnet
pump
Bipolar Technology 2.2 En
Al
anode
43
Contamination
Boron,
The
smallest
source
danger
phosphorus
of
ofchip
contamination
contamination
structure
or arsenic
iscan
is5are
not
µm
be
intentionally
only
width.
airborne
in The
thedust,
added
to silicon.of
diameter
fragments
impossibility
Other
ofhuman
of
various
early
elements,
hair
detection
materials,
is about
suchwhich
contaminated
as
50 gold,
µm.
usually
As
copper
we can
or
sodium
see
chemicals
becomes
on the
can
evident
as
microphotography,
badly
well during
as
influence
a human
testing
thethe
being
silicon
only
hair
or,
- perspiration,
properties,
caught
what isoneven
the
evensurface
chip
hair,
worse,
skin-particles
inas
anan
imponderable
can
unreliable
absolutely
or make-up.
product
amount
damage
On
by- this
a
the
the
customer.
next
ischip.
called
slide
On the
contamination.
video,
picture,
there
thereare
isThe
asunflower
photo
silicon
of pollen
contamination
a silicon
grains
fragment
caught
is caused
taken
on
thescanning
by
achip
diffusion
surface.
electron
of undesirable
microscope.
admixtures from impure
surface or environment.
VIDEO 320 x 240
196,9665
79
63,546
Au
Cu
29
Gold 22,98977
Copper
11
Testing
Bipolar Technology 2.2 En
Na
Sodium
44
Silicon Fragment
Bipolar Technology 2.2 En
45
Clean Rooms
1 000 000 dust particles
per cubic foot (approx. 30 l)
Anfan
In
Therefore
A
The
People
standard
imponderable
air
sufficiency
forces
working
in the
special
environment,
air
clean
of
above
inamount
clean
oxygen
the
rooms
clean
the
rooms
there
of
and
filters,
has
rooms
anaare
10
are
admixture
compensation
the
to
built
need
about
10
air for
000
gets
sufficiency
1can
000
dust
of000
considerably
airborne
semiconductor
through
particles
of
the
oxygen.
air loss
the
particles
in Wall
one
are
filters
influence
devices
provided
cubic
leakage
in
into
one
foot
the
the
manufacturing.
and
cubic
byaccording
room
silicon
continuous
the
foot
and
technological
properties.
ofittoair
isa
These
fresh
exhausted
(30
degree
l).
air
are
The
of
Details
manufacturing
the
through
filtration
exhaustion
induction
rooms
dimensions
the
and
and
with
cause
perforated
itconditioning
has
of
a raised
semiconductor
the
controlled
onloss
the
floor.
perforated
chip
of
(about
After
atemperature
part
are
chips
20%).
afloor
comparable
of
temperature
conditioned
would
and
and
abe
dual
to
the size
problematic
ceiling
and
humidity.
air.
humidity
provided
of airborne
inconditioning,
such
withparticles.
an
airenvironment.
filters.
the air is forced above
the filters again.
fresh air
induction
exhaust
vent
CEILING FILTERS
flow rate
0,5 m/s
temperature
and
humidity
control
over pressure
10-15 Pa
1 000
leakage
perforated floor
Bipolar Technology 2.2 En
46
Semiconductor Hygiene and Wafer Handling
Semiconductor
People
air-conditioning
working
hygiene
in
the
clean
means
with
behavior
air
wear
filtration
special
rules
create
for
clothes
an
On
Silicon
It
The
is the
not
wafers
wafers
enclosed
allowed
areare
must
processed
atvideo,
be
fragile
alltogether
thoroughly
to
there
touch
material,
onrooms
is
athe
cleaned
the
large
silicon
which
handling
scale,
before
influences
wafer
inprocess
batches.
with
every
the
appropriate
people
made
ofhandling
working
awafers
material
environment
in
the
that
does
forfrom
rooms
the
not
release
and
for
dust
handling
particles.
with
way
one´s
During
high-temperature
from
of
the
hand.
low
temperature
There
unloading
with
operation.
is
them.
aclean
special
operations,
This
vacuum
asemiconductor
is
cleaning
done
there
wand
in
are
machine
anused
25
wafers
for
up
technology
A
hood,
silicon
a face
wafers
inside
mask
and
the
clean
other
rooms,
clean
room
materials.
but
shoes
it would
are
not
the be
the
in
equipment
to
athe
handling.
teflon
placing
or
similar
polypropylene
The
them
wafer
toon
aand
washing
the
isclean
sucked
oxidation
cassettes.
machine.
by
furnace
means
For
Only
high
loader.
of the
the
possible
parts
ofsimilarly
the
to maintain
clothes.
They
the clean
wear
gloves
without
on
their
any
hands.
other
wand,
temperature
washing
powder
processes,
toisareplaced
vacuum
the
wafers
cleaner.
byrooms
sulfuric
are
Nevertheless,
acid,
fixed
in
various
precautions.
automatic
quartz,
hydrochloric
graphite
devices
acid,
orhydrogen
are
silicon
always
carbide
peroxide
preferred
fixtures.
and
forammonium
the handling.
hydroxide. Then the wafers are properly rinsed in
deionized water and dried in a spin-drier.
Bipolar Technology 2.2 En
VIDEO 320 x 240
47
Process Control
Thevideo
Perhaps
On
one
technological
silicon
the
clip,simplest
there
wafer,
process
isthere
as
a procedure
well
consists
are
ashundreds
thefrom
of
most
tens
oxide
to
often
of
operations.measurement
inspection
thousands
thickness
is
chips
Achieving
an inspection
and thousands
of up
theof
to
specified
dust
a record
silicon
particles
parameters
of
wafers
the
on are
the
in one operation
silicon
processed
results
wafer
into every
the
before
control
is
day.
aand
condition
Therefore
chart.
after an
forthe
operation.
starting
operation
the
An
subsequent
operator
results
are
check
statistically
operation.
the wafer
processed
Therefore
surface every
in
and
a flow
the
operation
of
ends withlight.
intensive
operations
an
areinspection
Even
controlled
a very
orby
asmall
statistical
measurement.
particles
methods
cause- a
visible
by
means
lightofscattering.
control charts
This -inspection
through computers.
can be often
seen on the enclosed video clips.
Bipolar Technology 2.2 En
VIDEO 320 x 240
48
Materials for the Semiconductor Technology
The water
semiconductor
purity must
technology
be on therequires
silicon purity
extremely
level,clean
so this is
environment
the
question of
and
units
materials.
to tens Water
gramsisofone
impurities
of the most
in thousand
often
used(million
tons
materialliters)
during
of the
water.
technological
A similar purity
process.
mustHighly
also be
clean
in
water chemicals
other
is preparedlike
byacids,
the reverse
solvents
osmosis
and photoresist.
and the final
cleaning processes in ion exchangers. It is called deionized
water, or simply DI water.
Contamination
Photolitography and Etching
Reverse Osmosis
Bipolar Technology 2.2 En
49