Evaluation of ULPA/prefilter media for the reduction of airborne boron contamination

摘要

An investigation was conducted to evaluate various combinations of filter media to minimize boron contamination in clean room environments. Three $mu@PVC fan/blower test chamber modules were constructed, each with a different filter media and placed in a clean room environment. The various media tested included a standard Ultra Low Penetration Air (ULPA), an expanded polytetrafluoroethylene (PTFE) ULPA, and a combination of PTFE with a chemically active prefilter (carbon based). An encapsulation procedure was used to trap airborne contamination on the exposed area of a wafer and sandwich contaminants. The sandwiched contaminants at these controlled interfaces are tested for boron contamination levels. Secondary Ion Mass Spectroscopy (SIMS) was used to determine boron contamination levels at each controlled interface. Results from these experiments were used to quantify the effectiveness of different types of ULPA filters on airborne boron contaminants.