The Identification and Elimination of Human Contamination in the Manufacture of IC´s

The semiconductor industry has come a long way in the campaign to eliminate the major failure mechanisms from its product. The battles against moisture, sodium, migration, purple plague, pin holes, and oxide breakdown have been largely won. Current mature product reliability has reached the 100 FIT level and there is every reason to take satisfaction in this achievement. Recently, there have been several costly systems failures that have been traced to random contamination originating from the human body. Thus circuits which have achieved an enviable generic reliability track record may also experience a small number of random failures. Since these random failures can cause complete system failure in automobiles as well as spacecraft, it is now appropriate to take a close look at the source of contamination, the way in which it reaches the circuit, and the methods to eliminate it. In this paper, the human sources of contamination were examined in detail. The chemical nature of skin, hair, sweat, spittle and mucus was documented. The method of transmission such as talking and coughing will be graphically demonstrated in a movie utilizing dark field techniques to illustrate the not so obvious extent of human contamination projection during talking. Next the SEM and EDAX were used to identify the contamination once it was deposited on the wafer or chip. Spittle was identified by the characteristically round spots containing a large amount of potassium chloride as the main constituent.