zsc

778 views

Published on

Published in: Business, Technology
0 Comments
0 Likes
Statistics
Notes
  • Be the first to comment

  • Be the first to like this

No Downloads
Views
Total views
778
On SlideShare
0
From Embeds
0
Number of Embeds
2
Actions
Shares
0
Downloads
9
Comments
0
Likes
0
Embeds 0
No embeds

No notes for slide

zsc

  1. 1. Processing and Layout <ul><li>Clean Room Requirements </li></ul>
  2. 2. Processing and Layout <ul><li>Silicon Start Material - epitaxy (on-arrangement) </li></ul><ul><ul><li>Czochralski Method </li></ul></ul><ul><ul><li>Bridgeman Method </li></ul></ul><ul><ul><li>Current state of the art is 8” wafer dia. </li></ul></ul>
  3. 3. Processing and Layout
  4. 4. Processing and Layout <ul><li>Thermal Oxidation </li></ul><ul><ul><li>Si + O 2 --> SiO 2 </li></ul></ul><ul><ul><li>Si + 2H 2 O --> SiO 2 + 2H 2 </li></ul></ul><ul><ul><li>Gate Oxidation </li></ul></ul><ul><ul><ul><li>as thin as 40Å for a L=0.18µm CMOS Technology </li></ul></ul></ul><ul><ul><li>Field Oxidation </li></ul></ul><ul><ul><ul><li>thick 0.5µm to 1.5µm </li></ul></ul></ul>
  5. 5. Processing and Layout <ul><li>PhotoLithography </li></ul><ul><ul><li>Photoresist: optically sensitive polymer which when exposed to UV light changes its solubility in specific chemicals </li></ul></ul>
  6. 6. Processing and Layout <ul><li>Photo Mask Generation </li></ul>
  7. 7. Processing and Layout <ul><li>Etching </li></ul><ul><ul><li>Wet etching (isotropic) </li></ul></ul><ul><ul><ul><li>Use chemicals which react with underlying material but does not react with photoresist </li></ul></ul></ul><ul><ul><li>Dry Etching (anisotropic or isotropic) </li></ul></ul><ul><ul><ul><li>Use ionized gases and which react with underlying material but does not react with photoresist </li></ul></ul></ul>
  8. 8. Processing and Layout <ul><li>Doping Techniques - Diffusion </li></ul><ul><ul><li>Wafers placed in a heated quartz tube (800°C to 1150°C) </li></ul></ul><ul><ul><li>Thermal energy results in dopant species to diffuse in the silicon lattice </li></ul></ul>
  9. 9. Processing and Layout <ul><li>Doping Techniques - Ion Implantation </li></ul><ul><ul><li>Energetic Ions are bombarded onto the silicon wafer </li></ul></ul><ul><ul><li>The depth and shape of the profile after implant can be modelled and depends on the energy and dose of the implant species </li></ul></ul>
  10. 10. Processing and Layout <ul><li>Chemical Vapor Deposition </li></ul><ul><ul><li>Silicon Nitride (Si 3 N 4 ) </li></ul></ul><ul><ul><ul><li>3SiH 4 + 4NH 3 ------> Si 3 N 4 +12H 2 </li></ul></ul></ul><ul><ul><ul><li>resistant to oxidation </li></ul></ul></ul><ul><ul><li>Poly-Silicon </li></ul></ul><ul><ul><ul><li>SiH 4 -----> Si + 2H 2 </li></ul></ul></ul><ul><ul><li>Oxide </li></ul></ul><ul><ul><ul><li>SiH 4 +O 2 -----> SiO 2 + 2H 2 </li></ul></ul></ul>
  11. 11. Processing and Layout <ul><li>Device Isolation </li></ul><ul><ul><li>LOCOS (Local Oxidation of Silicon) </li></ul></ul><ul><ul><li>Use Nitride as a mask during oxidation </li></ul></ul>

×