Transcript Document 354825

Slovak University of Technology
Faculty of Material Science and Technology in Trnava
Machine Tools And
Devices For Special
Technologies
Semiconductive component manufacturing
Semiconductive component
manufacturing
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Semiconductors are matters, those electric resistance
is manifold greater as is electric resistance of metals
and at the same time their resistance be of the essence
smaller as is a resistance of insulating materials.
semiconductive materials are silicon, intermetallic
allied substances AsGa, InP...
Basic raw material to semiconductive component
manufacturing is slice cutted from monocrystal,
which is wrought that its surface does not contain any
crystallographic defect
Semiconductive part production
sequence
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Initial cleaning – zone melting
Monocrystal drawing
Mechanical treatment
Epitaxy
Lithographic techniques
Diffusion
Ion implantation
Contacting
Encasing
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Cooling
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Initial cleaning – zone melting
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it needs enough purify base material  purity of base material
must be very high  suitable is using of zone melting
High-frequency heating is realising by inductance. This way
heating is very advantageous, because heat rise in entire
section of ingot.
Scheme of zone melting
Monocrystal drawing
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ingot is compound from aggregate of chaotically placing
crystals this is component manufacturing unusable, be needed
the monocrystal with proper orientation of crystal grid - called
monocrystal drawing by CZOCHRANSKI method.
Monocrystal drawing
Mechanical treatment
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With respect of alloys concentration the monocrystal is cutting
by diamond saw to slices by thickness 0,1 till 2 mm - called
WAFERs
Slice surface is after mechanical machining damaged to depths
this is a reason for finally etched and glazed into high gloss
Monocrystal splitting to wafers
Epitaxy
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On the surface of slices material are allow accrue the
additional silicon layer with the accurately defined
concentration of additive material  this process of
thin layer accretion is called epitaxy.
Epitaxy
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from gas phase
from liquid phase
from organo - metallic phase
Lithographic techniques
Chosen slice surface parts were treat by doping
process, we must at the slice surface to every
doping process create a mask.
 Advantages of the mask:
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Very thin layer,
Homogeneous,
Without poorness,
All right adhere to base.
Lithographic techniques
Masking layer is embossed by photolithography.
On the base slice with layer of the SiO2 is
accrued the thin layer of photoresist. Rest of
the photoresist is removed from the surface
and the slice is prepared for next processing.
Diffusion
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Penetration of the concrete material atoms into
solid phase of semiconductive materials.
According to diffusion alloys generated:
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Areas P
Areas N
Both with suitable electrical properties.
In some cases the gold is used for diffusion.
Ion implantation
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the process, by which donation run over at low
temperature (ideal is temperature around 20°C)
To doping is used ions of atom of doping matters
Ionic implantator is a vacuum device
Ions forced in semiconductor slice are not integrated
in crystal grid, hence it needs semiconductor slice
normalize yet
Contacting
Cross interconnection within circuit is
realising by conductive linkage networks
 On circuit terminals from encasement is made
the contact plate from Al  connecting
between contact plate and output with wire
attached with thermocompress welding.
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Encasing
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This is an important operation, important is suitable
encasement selection, because mostly is the
encasement the most expensive part of entire
integrated circuit.
Case must satisfy entire row requirement:
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Protect integrated circuit before environment,
Dissipate heat from IC into environment,
Allow manipulation with IC (soldering, assembly...),
Must be probably the cheeps.
Encasing
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Used cases:
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Metal
 Ceramics
 Plastic
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Dimension and shape of casing are
standardised.
Cooling
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Casing consist thermal outlet where is
connect external cooler.