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This paper focuses on the introduction and qualification of the in situ particle monitor so called High Yield Technology (HYT) sensor on an Axcelis NV-GSD/E 200mm high current batch implanter to detect particles in real time during the implantation process. The particles on the wafer surface were measured with Surfscan and their composition was determined by means of Energy Dispersive X-ray (EDX) analysis. A good correlation between the HYT particle counts and surface particles on dummy wafers as well as defect densities measured on wafers structured with photo resist was found. Moreover, there is a well defined linear correlation of the HYT particle counts to the yield loss. To reduce the level of particle contamination, preventive maintenance procedures were optimized and the hardware in the beam line was modified. In order to minimize structural damage from high velocity particles, the disk drive was upgraded from a belt drive to a direct drive which offers the possibility to decrease the spin speed, thus to reduce the kinetic energy of the particles. Furthermore, measures to repair the already broken structures and to reduce the impact of particles on the products were taken. Depending on the values of the HYT in situ particle monitor, rework steps on various products were introduced. The results of these actions are discussed in combination with the costs. © 2006 American Institute of Physics [ABSTRACT FROM AUTHOR]