A methodology has been developed for preparing wafers for use in tests measuring the particle removal efficiency of various wafer-cleaning techniques. In addition to yielding a uniform deposition of particles of known size and composition, the method incorporates chemical cleaning of the wafers prior to particle deposition to ensure that wafer surface chemistry is also controlled. In this study, the methodology was used to compare the particle removal efficiency of four chemical cleaning methods: two modified RCA procedures, megasonic cleaning, and a combination of the two types of processes. All of the methods were found to be very efficient in removing PSL particles, with removal efficiencies >97% for particles ≥ 0.3-μm diam. The combined cleaning technique achieved the best removal efficiency. In general, particle removal efficiencies decreased with decreasing particle size. Future work is planned to investigate the techniques' efficiency in removing silica particles and particles of other compositions.
|Original language||English (US)|
|Pages (from-to)||37-40, 98|
|State||Published - May 1 1990|