Patent Number: 6,168,085

Title: System and method for cascade control of temperature and humidity for semi-conductor manufacturing environments

Abstract: A system and method are provided for controlling temperature and humidity of an environment for a process chamber for semiconductor manufacturing materials. A supply of filtered, temperature and humidity controlled gaseous working fluid is provided to a process chamber, and is controlled by cascade control based upon sensing of environmental parameters to be controlled both upstream and downstream of a chemical filter, which can be a charcoal filter. A controller determines a first control error output by comparing a desired process parameter set point for the controlled environmental parameter of the gaseous working fluid with the first sensed value, determines a second set point from the first control error, and controls the supply of the temperature and humidity controlled gaseous working fluid based upon the second set point.

Inventors: Garcia; Kenneth P. (Salinas, CA)

Assignee: Semifab Incorporated

International Classification: G05D 27/00 (20060101); G05D 27/02 (20060101); G05P 022/00 ()

Expiration Date: 01/02/2018