Sulfuric Acid → Sulfuric acid, hafnium(4+) salt (2:1)

Participants

Reaction Steps

After the unwanted hafnium oxide remaining in the bottoms of grooves 56a in the high dielectric film 52 on the wafer W reacts with the sulfuric acid to form hafnium sulfate, the wafer W is withdrawn from the hot concentrated sulfuric acid 62 in the treating tub 61. As shown in FIG. 7B, the wafer W is loaded into a cleaning tub 63 storing deionized water 64. The wafer W is immersed in the deionized water 64 in the cleaning tub 63. Though not shown, deionized water is continuously supplied to the cleaning tub 63 through an inlet port formed in a bottom thereof, and is overflowing an upper portion of the cleaning tub 63. By immersing the wafer W in the deionized water 64, the hafnium sulfate on the wafer W dissolves into the deionized water 64 to be removed from the wafer W.

Provenance & Evidence