Selectivity between thermally grown oxide and LPCVD nitride during hot phosphoric process is a well known key point of shallow trench isolation (STI) module integration. The main challenges are to control the step height and the pad oxide remaining thickness. Actually, following the technology shrinks from 120 nm to 65 nm, these parameters become critical for the lithography steps sensitivity regarding previous patterning and for the Sac On Pad integration. The process robustness is improved by saturating the initial chemical and by refreshing the phosphoric acid during the bath lifetime. The highlights are a process stability improvement, a H/sub 3/PO/sub 4/ filter lifetime increase and an overall better tool availability.

Today, batch processes are widely used in the industry for all surface preparation applications. This batch strategy, which is also used in the thermal treatment area (furnaces), is one of the main detractors for cycle time and fab flexibility in ASIC world. This statement combined with the footprint, the price and the very high DIW consumption of the 300mm conventional wet benches (WB), has been the main driver for the introduction of single wafer cleaning tool in the Crolles 2 facility.