Microelectronic Fabrication

Introduction to Microelectronic Fabrication

Lecture 1

January 11th, 2006

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Brief overview of microelectronic fabrication •Dominant material: Silicon •Technology size •MOSFET fabrication •Safety

Dominant material: Silicon

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Obtaining ultrapure Si (other technology)

Robert F. Pierret, Semiconductor Device Fundamentals, p.17

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Single-crystal formation

• Bridgmann method • Czochralski method

USNA (lecture notes), http://www.usna.edu/EE/ee452/LectureNotes/05-Processing_Technology/15, 10/03/04

Dominant material: Silicon

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Advantages of Si in fabrication

• Easily oxidized to form SiO2 • SiO2 acts as a “good” barrier layer • Other barrier materials: Si3N4, photoresist, metals, etc

Technology size

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Wafer size increases

• Wafer must be thicker • Diminish the production cost • Yield is higher

Richard C. Jaeger, Introduction to Microelectronic Fabrication, p.3

Technology roadmap

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Reduce the size of devices

• Increase the number of devices per wafer

UMC, http://www.umc.com.tw/english/process/a.asp

MOSFET fabrication

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Metal-oxide-semiconductor field-effect transistor (MOSFET) Technology size: Distance between drain & source

Robert F. Pierret, Field Effect Devices, p.72

MOSFET fabrication

http://www.ecse.rpi.edu/~schubert/Course-ECSE-6290%20SDM-2/1%20MOSFET-2%20Fabrication.pdf

Top view

Field oxide

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Channel length

Source

Drain

Safety

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Safety Issues

• Variety of acids and bases used for cleaning and etching

Can burn skin  Fumes can irritate eye

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• Toxic or explosive gases

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Ion implantation, LPCVD and epitaxial growth

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Understand toxicity & safe handling practices

Remarks

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Device physics: ECSE-432 ECSE-533

Thermal Oxidation of Silicon

http://www.ecse.rpi.edu/~schubert/Course-ECSE-6290%20SDM-2/1%20MOSFET-2%20Fabrication.pdf

Discussed Topics

The Oxidation Process  Modeling Oxidation  Factors Influencing Oxidation Rate  Dopant...