Continuous monitoring and mini-environments: closing the environmental-control loop

A photolithography process has been designed for use at IBM´s semiconductor manufacturing facility, in Essex Junction, Vermont that incorporates the use of mini-environments with continuous, real-time environmental monitoring and control. The goals for this system were to significantly reduce human contact with the process and product, isolate the tool environment, and continuously monitor all relevant environmental parameters, including airborne particle contamination, ambient air temperature, and relative humidity. Implementing this system has provided a new level of isolation between product and the operator. With this isolation and tight environmental control, an improvement in cleanliness of two orders of magnitude relative to the, clean room aisle has been achieved. Continuous monitoring of environmental parameters adds a means of maintaining and optimizing the systems performance. Investigations made into the correlations between a variety of environmental factors and process performance are discussed