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4_Semiconductor Manufacturing Technologies - Coggle Diagram
4_Semiconductor Manufacturing Technologies
1 Wafer preparation
sottofasifasi
Polysilicon Refining
otteniamo: Mettallurgic grade silicon
Crystal Pulling (Czochralski process)
silicon purification and deposition and milling
Wafer Slicing & Polishing (tagliato e lucidato)
Epitaxial Silicon Deposition (Additive micro fabrication processes)
Materials
Polysilicon
semiconductor
isotropic material
Silicon dioxide
excellent thermal and electrical insulator
Single crystal silicon
semiconductor, optimal heat conductor
anysotropic crystal
Silicon nitride
excellent electrical insulator
Aluminium
Metal – excellent thermal and electrical conductor
4 Design
Establish Design Rules
Circuit Element Design
Interconnect Routing
Device Simulation
Pattern Preparation
3 Front end process
Deposizione di nitruro di silicio (LPCVD)
Deposizione di polisilicio (LPCVD)
Ossidazione termica
Ricottura (Modifying micro fabrication processes)
5 Photolithography
Processi
di esposizione
rivestimento fotoresistenti
mezzo ottico per trasferire i motivi su un substrato.
7 Etching
Sutractive microfabrication process
ETCH BACK
DEPOSIT THIN FIL OF DESIRED MATERIAL
coat and pattern PR
etch film using photoresist as mask
remove PR
LIFT OFF
coat and pattern PR
add deposit thin film of desired material
swell photoresist with a solvent
remove pr and thin film above it
9 Cleaning
2 Thin films
2 tipi
Chemical Vapor Deposition (CVD)
– Reactive gases interact with substrate
• Atmospheric pressure – APCVD
• Low pressure – LPCVD
• Plasma enhanced – PECVD
• High density plasma - HDPCVD
– Used to deposit Si and dielectrics
– Good film quality
– Good step coverage
STEPS
Transport reactants via forced convection to reaction region
Transport reactants via diffusion to wafer surface
Adsorb reactants on surface
Surface processes: chemical decomposition, surface migration, site incorporation, etc.
Desorption from surface
Transport by products through boundary layer
Transport by products away from deposition region
Physical Vapor Deposition (PVD)
– Used to deposit metals
– Line of sight
– Dielectric
– High purity
TIPI
Sputtering
Evaporation
Vantaggi
Versatile – deposits almost any material
Very few chemical reactions, Little wafer damage
Limiti
Line-of-sight
Shadowing
Thickness uniformity
Difficult to evaporate materials with low vapor pressures
7 Ion Implantation
i droganti (ioni) vengono impiantati nel substrato come "proiettili" ad alta energia.
vantaggi
il profilo di concentrazione nel substrato può essere controllato
trattamento a temperatura intermedia
Fasi
Well Implants
Channel Implants
Source/Drain Implants
8 Planarization
(a) Oxide formation
(c) Deposition of dopant atoms
(d) Diffusion of dopant atoms in the exposed regions
(b) Oxide removal
10 test and assembly
Electrical Test Probe
Die Cut and Assembly
Final Test
Die Attach and Wire Bonding