High controllability and low cost APM process by one-bath type wet-bench for multi gate oxide pre-cleaning

We propose a sufficiently effective APM process by one-bath type wet-bench to the multi oxide gate precleaning from the viewpoint of the high controllable thermal oxide etching rate and the high performance pre-cleaning for ultra-thin gate oxide. In the one-bath type wet-bench, cleaning solution is freshly changed per batch. Therefore, we estimated the ability of the cost reduction of the APM process. As the result, it was clarified that the composition of 0.1:0.1:5 (NH/sub 4/OH:H/sub 2/O/sub 2/:H/sub 2/O) in the one-bath type wet-bench is almost equivalent cost level to the conventional multi-bath type wet-bench and can realize the high controllability and performance for the pre-cleaning of multi gate oxide.