Control system for environmental chamber of semiconductor lithography machine utilized in semiconductor industry, has heat exchanger connected to controller, where actual measured variable is produced to control exchanger

摘要

#CMT# #/CMT# The system has a temperature measuring device measuring temperature difference of medium streams (M1, M2) e.g. air. A heat exchanger (3) is connected to a controller (5) that obtains a measured variable representing actual temperature difference of the medium streams and a reference value (6) as an input signal. Thermoelectric voltage (Ut) is generated in presence of the temperature difference of medium streams, where the temperature difference is determined from the voltage, and an actual measured variable is produced to control the heat exchanger. #CMT#USE : #/CMT# Control system for an environmental chamber of semiconductor lithography machine that is utilized in a semiconductor industry. #CMT#ADVANTAGE : #/CMT# The system precludes uncontrolled drift of a temperature measurement chain and associated control loops in a reliable and simple manner while avoiding influence or realizing only negligible influence of drift behavior of the temperature measurement chain. #CMT#DESCRIPTION OF DRAWINGS : #/CMT# The drawing shows a schematic view of a measuring device for medium streams using a measuring element. M1, M2 : Medium streams Ut : Thermoelectric voltage 3 : Heat exchanger 5 : Controller 6 : Reference value.