Abstract
Some analytical procedures were studied for the determination of ultratrace concentra-tions of Na, K and Fe in photoresist used ULSI by GFAAS. These procedures were as follows: 1) acid decomposition (HNO3+HClO4); 2) tetramethylammonium hydroxide (TMAH) digestion; 3) dilution by acetone; 4) extraction with HC-4-methyl-2-pentanone (MIBK) for Fe; and 5) extraction with hot water for Na and K. The results of this analysis showed the observed values by these procedures were in good agreement with each other. The detection limits were Na, K: 0.01 ppb, Fe: 0.1 ppb respectively.
