Abstract
Cleanrooms of varying class categories are used to solve different problems
requiring different levels of air purity. There is not a simple correlation
between cleanroom Class and feature size being processed. While it is obvious
from cleanroom classifications that Class 1 will be required for sub 0.25
micron IC production, the use of minienvironments, particularly in 300mm fabs,
can dictate the use of a higher Class cleanroom, as shown in Figure 1.1. With
a 200mm fab, automation and SMIF are options. With a 300mm fab, automation is
required and SMIF technology is incorporated with FOUPs, and every 300mm tool
has a FOUP interface
The quality of chemicals and materials entering the fab area should be one of
the most important concern of personnel in a semiconductor manufacturing
facility. In order to undertake proper evaluation of chemicals and their
suppliers, a total awareness program must be initiated in the facility. To
achieve this goal, the primary requirement must be a commitment by management
that personnel and monetary resources are dedicated to the purity issue
regardless of cost.
This report addresses the issues of contamination of Si and GaAs wafers from
liquid and gaseous chemicals, de-ionized water, and ambient air. The latest
developments in the identification, monitoring, and removal of these
contaminants are described, together with the trends in usage.
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