Is there an existing study or detailed recommendation on what cleanroom classification is desirable or sufficient for a specific field of application? We're a semiconductor test facility. We test IC's (electrical and mechanical) of various package configurations, we also test wafers. Our wafer test facility is currently an ISO class 7 (10k) cleanroom. Our Test facility for packaged IC's is ISO Class 8(100K). This is the way it is since 10 years ago (though previously, classification was of FED 209). I am looking for specific risks to product quality or process operation should my facility cleanliness go beyond classification limits. Wouldn't ISO class 8 be sufficient for wafer testing? or ISO Class 9 for packaged IC testing?