EE 330 Lect 10 Fall 2011

EE 330 Lect 10 Fall 2011 - EE 330 Lecture 10 IC Fabrication...

Info iconThis preview shows pages 1–10. Sign up to view the full content.

View Full Document Right Arrow Icon
EE 330 Lecture 10 IC Fabrication Technology Part III - Epitaxy - Polysilicon - Interconnects - Back-end Processes
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
IC Fabrication Technology Crystal Preparation Masking Photolithographic Process Deposition Implantation Etching Diffusion Oxidation Epitaxy Polysilicon Contacts, Interconnect and Metalization Planarization Review from Last Time
Background image of page 2
Etching Selective Removal of Unwanted Materials • Wet Etch – Inexpensive but under-cutting a problem • Dry Etch – Often termed ion etch or plasma etch Review from Last Time
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Diffusion Controlled Migration of Impurities Time and Temperature Dependent Both vertical and lateral diffusion occurs Crystal orientation affects diffusion rates in lateral and vertical dimensions Materials Dependent Subsequent Movement Electrical Properties Highly Dependent upon Number and Distribution of Impurities Diffusion at 800 o C to 1200 o C Source of Impurities Deposition Ion Implantation Only a few A o deep More accurate control of doping levels Fractures silicon crystaline structure during implant Annealing occurs during diffusion Review from Last Time
Background image of page 4
Oxidation SiO 2 is widely used as an insulator Excellent insulator properties Used for gate dielectric Gate oxide layers very thin Used to separate devices by raising threshold voltage termed field oxide field oxide layers very thick Methods of Oxidation Thermal Growth (LOCOS) Consumes host silicon x units of SiO 2 consumes .47x units of Si Undercutting of photoresist Compromises planar surface for thick layers Excellent quality Chemical Vapor Deposition Needed to put SiO 2 on materials other than Si Review from Last Time
Background image of page 5

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Oxidation SiO 2 Thermally Grown SiO 2 - desired growth Photoresist Patterned Edges X 0.47 X p - Silicon Review from Last Time
Background image of page 6
Oxidation SiO 2 Thermally Grown SiO 2 - actual growth Photoresist Patterned Edges Bird’s Beaking p - Silicon Review from Last Time
Background image of page 7

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Oxidation Thermally Grown SiO 2 - actual growth Patterned Edges Nonplanar Surface p - Silicon Review from Last Time
Background image of page 8
Shallow Trench Isolation (STI) p - Silicon Photoresist Pad Oxide Silicon Nitride
Background image of page 9

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 10
This is the end of the preview. Sign up to access the rest of the document.

This document was uploaded on 01/31/2012.

Page1 / 51

EE 330 Lect 10 Fall 2011 - EE 330 Lecture 10 IC Fabrication...

This preview shows document pages 1 - 10. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online