Semiconductors Material, Components, and Manufacture

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SemiconductorsMaterial, Components, and
Manufacture

• Joseph Stith
• February 2007

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Outline

• Atom Electron Energy Levels
• Electrical properties of materials
• Doping
• Diodes
• Capacitors
• Transistors
• High-K dielectric / Metal Gate
• Flash Transistor
• Manufacturing Process
• Semiconductor Mfg History
• Possible Futures
• Intel Arizona Fabs

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Electron Energy Levels

• Electrons collect in various regions, often
  referred to as Energy Levels, shells, orbitals,
  etc. Drawn representatively as circles.
• Atoms seek stability Full energy Levels 2, 8,
  8,
• How many electrons does this Silicon atom seek?
• 4
• Where does it get the additional electrons?
• Sharing outer shell electrons with other atoms
  that also want additional electrons, creating a
  bond.

H20 NaCl SiO2
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Electrical Properties

• Insulator
• No free electrons
• Conductor
• free electrons
• Semi-Conductor
• No free electrons
• Insulator
• But

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Doping

• Increases conductivity
• N-Type (5 outer electrons)
• Phosphorus or Arsenic
• P-Type (3 outer electrons)
• Boron

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Diode

• P-Doped and N-Doped Regions
• Both regions are conductors
• Junction may not be a conductor

Holes Electrons flowing Depletion
Region Positively Biased
Stable Covalent Electrons Depletion
Region Negatively Biased
Holes
Electrons
Electrons
Holes
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Capacitor
-

• Two conductors separated by an insulator
• Plates charge, but no current flows through the
  capacitor.
• Once charged, there is an electrical field
  between the plates.
• Discharging one plate (e.g., attaching to ground)
  will still leave an electrical field.
• Electrical field will attract opposite particles
  in other plate.

-

-
-
-

-

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Transistor
N P N

• With no gate charge, no current.
• Two reversed diodes
• One capacitor
• With a positive gate charge, a channel of
  negative ions form at the top of the P region,
  allowing current to flow.

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High-k Metal Gate
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Flash Transistor

• Flash memory still uses MOS Transistors for
  control functions.
• Uses Flash transistors to store data
• Floating Gate surrounded by insulator

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Manufacturing Process

• Fab
• Add material
• Implant
• Diffusion/Anneal
• Heat raises energy of atoms to allow them to
  settle to a more stable location.
• Thin Films
• Sputter, Oxidation, Chemical Vapor Deposition
• Remove material
• Etch (chemical acids) Wet (undercuts), Plasma
  (straight).
• Planar (mechanical)
• Determining the pattern/Lithography
• Spin on a layer of Resist
• Expose to light through pattern (negative)
• Wash off the unexposed resist
• Add material (below)
• Wash off the exposed resist
• Metrology (lot OOC, Tool OOC, Trending to OOC)
• C4
• Sort

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Manufacturing a Transistor
1. Layer SiO2 2. Apply Resist 3. Expose Resist 4.
Remove unexposed 5. Etch SiO2 5. Remove
exposed 6. Layer Polysilicon gate 7. Apply
Resist 8. Expose Resist 9. Remove unexposed 10.
Etch Polysilicon 11. Remove exposed 12. Dope
Silicon 13. Add SiO2 14. Apply Resist 15. Expose
Resist 16. Remove unexposed 17. Etch SiO2 18.
Remove exposed 19. Layer Aluminum 20. Apply
Resist 21. Expose Resist 22. Remove unexposed 23.
Etch Aluminum 24. Remove exposed
Gate Contact
METROLOGY
Source Contact
Drain Contact

• http//micro.magnet.fsu.edu/electromag/java/transi
  stor/index.html
• http//www.tel.com/eng/product/spe/spe.htm

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History
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Possible Futures
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Possible Futures
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Future Multi-Core - Polaris

• http//blogs.zdnet.com/OverTheHorizon/?p12

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Intel Arizona

• Chandler Blvd
• Offices
• Assembly Test development area
• Ocotillo
• F22 8 Fab - Closing Q1 2008, F32 will grow
  into the floorspace as it transitions to 32nm
• F12 12 Fab Running 65nm Converted from
  200mm - Converting to chipset fab.
• F32 12 Fab Startup 45nm - 3B - 184,000
  square feet of clean room space

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Questions?
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Backup
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Further Info

• http//micro.magnet.fsu.edu/electromag/java/silico
  ncreature/sailboat.html
• http//micro.magnet.fsu.edu/electromag/java/transi
  stor/index.html
• http//nobelprize.org/educational_games/physics/tr
  ansistor/function/index.html

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Contamination

• Class 1 clean room
• 10,000 times cleaner than an operating room.
• 1 particle (gt .5 micron) per cubic foot of air.
• FOUPs
• Allow for dirtier fabs
• Environment
• 72 degrees Fahrenheit
• 40 humidity
• Positive air pressure
• Assembly/Test less strict

Not Allowed Gum, perfume, makeup, pencils,
standard paper
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Electrons
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• http//winter.group.shef.ac.uk/orbitron/AOs/3d/ind
  ex.html

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• http//www.webelements.com/webelements/elements/te
  xt/Si/econ.html

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References

• http//computer.howstuffworks.com
• http//www.chemguide.co.uk/atoms/properties/atomor
  bs.htmltop
• http//www.chemguide.co.uk/index.htmltop
• www.webelements.com
• http//www.chemguide.co.uk/atoms/bonding/covalent.
  html
• www.sela.com/cmossem.htm
• http//cache-www.intel.com/cd/00/00/33/04/330432_3
  30432.pdf
• http//en.wikipedia.org/wiki/High-k_Dielectric