Welcome to the Vacuum Technology Module

The purpose of this module is to help the student understand how vacuum pumps and technology make it possible to achieve low pressures as needed for many semiconductor manufacturing processes. Accordingly, a reaction chamber - to be used as a process reactor - will be evacuated from atmospheric pressure (1 atm, or 760 torr) down to a tiny fraction of this pressure, typically 1 millitorr or less (10^-3 torr, or often 10^-6 torr or less). With this capability, reactant gases can be admitted into the chamber to a controlled pressure and used to process semiconductor wafers. The exercises provided will demonstrate:

• The use of mechanical pumps and turbo pumps to achieve various low pressures
  
• The relation of pump speed and chamber volume to the time required for pumpdown
  
• The venting of the chamber back to elevated or atmospheric pressure
  
• The combining of mechanical and turbo pump characteristics into a two-stage pumping system
  
• The mechanisms for controlling rate of pumpdown using bypass lines, as needed for particulate control
  
• The use of a turbo pump system in combination with bypass pumping for semiconductor processing