CMP slurry particle size spectrometer

The particle size distribution in Chemical Mechanical Planarization (CMP) slurries is critical to the proper performance of the CMP Planarization process. Instrumentation in the past has been developed to measure the average particle size. However, just knowing the average particle size of the slurry will not prevent damaging scratches from occurring on high value planarized wafers. Fundamental physical properties and behaviours of slurries are strongly affected by both particle size and particle size distribution. This paper describes the application of a new instrument designed specifically for the measurement of particle size distribution in CMP slurries, with polishing particles that can range in size from 30 nanometers to 1100 nanometers. This new instrument, called the SPS-100, can resolve sub-populations with size differences as little as 10% in diameter. Slurries that have suffered change in critical polish particle size due to motion or temperature caused agglomeration in transit can be quickly identified. Slurries that tend to settle during shipment can be quickly certified for use through the use of this new instrument, after the slurry is remixed. This paper presents data from the slurry particle size spectrometer for various slurries used in CMP.